1. The mechanism behind electromagnetic wave propagation cannot be attributed to ___________
a) Reflection
b) Diffraction
c) Scattering
d) Sectoring
Answer: d
Explanation: The mechanisms behind electromagnetic wave propagation are diverse. They can be greatly attributed to reflection, diffraction and scattering. Due to multiple reflections from various objects, the electromagnetic waves travel along different paths of varying lengths.

2. The propagation model that estimates radio coverage of a transmitter is called ___________
a) Large scale propagation model
b) Small scale propagation model
c) Fading model
d) Okumura model
Answer: a
Explanation: Large scale propagation model are useful in estimating the radio coverage area of a transmitter. They can predict the mean signal strength for an arbitrary transmitter-receiver (T-R) separation distance. They characterize signal strength over large T-R separation distances.

3. Propagation model that characterize rapid fluctuation is called _________
a) Hata model
b) Fading model
c) Large scale propagation model
d) Okumura model
Answer: b
Explanation: Fading models characterize the rapid fluctuations of the received signal strength over very short travel distance (a few wavelengths) or shot time durations (on the order of seconds).

4. Small scale propagation model is also known as _________
a) Fading model
b) Micro scale propagation model
c) Okumura model
d) Hata model
Answer: a
Explanation: Small scale propagation model is also called fading model. Fading model characterize the rapid fluctuations of the received signal strength over very short distance of a few wavelengths or short time duration. The propagation models are used to estimate the performance of wireless channels.

5. Free space propagation model is to predict ______
a) Received signal strength
b) Transmitted power
c) Gain of transmitter
d) Gain of receiver
Answer: a
Explanation: Free space propagation model predicts the received signal strength when there is an unobstructed line of sight path between transmitter and receiver. It assumes the ideal propagation condition that the environment is empty between the transmitter and receiver.

6. Which of the following do not undergo free space propagation?
a) Satellite communication system
b) Microwave line of sight radio links
c) Wireless line of sight radio links
d) Wired telephone systems
Answer: d
Explanation: EM signals when traveling through wireless channels experience fading effects due to various effects. But in some cases the transmission is with no obstruction and direct line of sight such as in satellite communication, microwave and wireless line of sight radio links.

7. The free space model predicts that received signal decays as a function of _________
a) Gain of transmitter antenna
b) T-R separation
c) Power of transmitter antenna
d) Effective aperture of the antenna
Answer: b
Explanation: As with most large scale radio wave propagation models, the free space model predicts that received signal decays as a function of the T-R separation distance raised to some power. Often it is given as a function of negative square root of the distance.

8. Relation between gain and effective aperture is given by ______
a) G=(4πA_e)/λ²
b) G=(4π λ²)/A_e
c) G=4πA_e
d) G=A_e/λ²
Answer: a
Explanation: The gain of the antenna is proportional to effective aperture area. Therefore, antennas with large effective apertures are high gain antennas and have small angular beam widths. Most of their power is radiated in a narrow beam in one direction, and little in other directions.

9. Relation between wavelength and carrier frequency is _________
a) λ=c/f
b) λ=c*f
c) λ=f/c
d) λ=1/f
Answer: a
Explanation: Wavelength is inversely proportional to carrier frequency. For electromagnetic radiation in free space, wavelength is a ratio of speed of light (c) and carrier frequency (f). Speed of light is 3*10⁸ m/s. The unit for wavelength is meters.

10. Which of the following antenna radiates power with unit gain uniformly in all directions?
a) Directional antenna
b) Dipole antenna
c) Isotropic antenna
d) Loop antenna
Answer: c
Explanation: Isotropic antenna radiates the power with unit gain uniformly in all directions. It is an ideal antenna. From practical point of view, there is no actual isotropic antenna. But, an isotropic antenna is often used as a reference antenna for the antenna gain.

11. EIRP is abbreviated as __________
a) Effective isotropic radiated power
b) Effective isotropic radio power
c) Effective and immediate radiated power
d) Effective and immediate ratio of power
Answer: a
Explanation: EIRP stands for Effective Isotropic Radiated Power. It is the amount of power that a theoretical isotropic antenna would emit to produce the peak power density observed in the direction of maximum antenna gain. EIRP also takes into account the losses in transmission line and connectors and includes the gain of the antenna.

12. Path loss in free space model is defined as difference of ________
a) Effective transmitted power and gain
b) Effective received power and distance between T-R
c) Gain and received power
d) Effective transmitter power and receiver power
Answer: d
Explanation: I Path loss is defined as difference of effective transmitter power and receiver power. Free-space path loss is the loss in signal strength of an electromagnetic wave that would result from a line-of-sight path through free space, with no obstacles nearby to cause reflection or diffraction.

13. Far field region is also known as _________
a) Near field region
b) Fraunhofer region
c) Erlang region
d) Fresnel region
Answer: b
Explanation: The far field is the region far from the antenna. In this region, the radiation pattern does not change shape with distance. Also, this region is dominated by radiated fields, with the E- and H-fields orthogonal to each other and the direction of propagation as with plane waves.

14. Fraunhofer distance is given by _____
a) 2D2/λ
b) 2D/λ
c) D/λ
d) 2D/λ2
Answer: a
Explanation: Fraunhofer distance, also known as far field distance is inversely proportional to wavelength. It depends on the largest physical dimension of the antennal (D). This distance basically denotes the boundary between far field and near field region.

15. Which of the following is called an ideal antenna?
a) Dipole antenna
b) Directional antenna
c) Isotropic antenna
d) Loop antenna
Answer: c
Explanation: Isotropic antenna is an ideal antenna that directs the power uniformly in all directions. It is a theoretical point source of electromagnetic. It is practically not possible. It is mainly used as a hypothetical antenna to measure the gain.

16. Which of the following mechanism do not impact propagation in mobile communication system?
a) Reflection
b) Diffraction
c) Scattering
d) Refraction
Answer: d
Explanation: Reflection, diffraction and scattering are the three basic propagation mechanism which impact propagation in mobile communication system. Large scale propagation model and small scale fading and multipath propagation are described by the physics of reflection, diffraction and scattering.

17. What is the dimension of object as compared to wavelength of propagating wave when reflection occurs?
a) Large
b) Small
c) Same
d) Very small
Answer: a
Explanation: Reflection occurs when a propagating electromagnetic wave impinges upon an object which has very large dimensions when compared to the wavelength of the propagation wave. Reflection occurs from the surface of the Earth and from buildings and walls.

18. When does the wave propagating from one medium to another gets partially reflection and partially transmitted?
a) Both mediums have same electrical properties
b) Both mediums have different electrical properties
c) Both mediums have same magnetic properties
d) Both mediums have different magnetic properties
Answer: b
Explanation: When a radio wave propagating in one medium impinges upon another medium having different electrical properties. The wave is partially reflected and partially transmitted.

19. What is the case of reflection, in course of second medium being a perfect dielectric?
a) Loss of energy during absorption
b) Total energy reflected back to first medium
c) No loss of energy in absorption
d) Total energy transmitted into second medium
Answer: c
Explanation: If the plane wave is incident on a perfect dielectric, part of the energy is transmitted into the second medium and part of the energy is reflected back into the first medium. There is no loss of energy in absorption.

20. What is the case of reflection, in course of second medium being a perfect conductor?
a) Loss of energy during absorption
b) Total energy reflected back to first medium
c) Partly transmission and reflection
d) Total energy transmitted into second medium
Answer: b
Explanation: If the second medium is perfect conductor, then all incident energy is reflected back into the second medium. There is no loss of energy during absorption.

21. Which of the following relates the incident and reflected & transmitted wave?
a) Fresnel transmission coefficient
b) Scattering coefficient
c) Diffraction coefficients
d) Fresnel reflection coefficient
Answer: d
Explanation: The electric field intensity of the reflected and transmitted waves may be related to the incident waves in the medium of origin through the Fresnel reflection coefficient. It is equal to the ratio of the amplitude of the reflected wave to the incident wave, with each expressed as phasors.

22. Reflection coefficient is not a function of __________
a) Material property
b) Diffraction loss
c) Wave polarization
d) Angle of incidence
Answer: b
Explanation: The reflection coefficient is a function of the material properties, and generally depends upon the wave polarization, angle of incidence and frequency of propagating waves. It is a parameter that describes how much of an electromagnetic wave is reflected by an impedance discontinuity in the transmission medium.

23. Polarized wave can be mathematically represented as sum of ________
a) Four orthogonal components
b) Two spatially adjacent components
c) Two spatially orthogonal components
d) Six orthogonal components
Answer: c
Explanation: A polarized wave may be mathematically represented as sum of two spatially orthogonal components. For an arbitrary polarization, super position may be used to compute the reflected fields from a reflecting surface.

24. The plane of incidence contains only incident rays.
a) True
b) False
Answer: b
Explanation: The plane of incidence is defined as the plane containing the incident, reflected and transmitted waves. The incident light is polarized with its electric field perpendicular to the plane containing the incident, reflected, and refracted rays.

25. Permittivity and conductivity are insensitive to ______ for a good conductor.
a) Operating frequency
b) Polarization density
c) Electric field
d) Property of material
Answer: a
Explanation: The terms permittivity and conductivity are insensitive to operating frequency when the material is a good conductor. In the case of conductors, it is evident that electric field inside a conductor is zero. That is because free charges reside only on the surface of conductor and not inside.

26. Velocity of electromagnetic wave can be given by _______
a) 1/√(μ∈)
b) μ/∈
c) 1/(μ∈)
d) μ∈
Answer: a
Explanation: For a medium with permittivity, ∈ and permeability, μ the velocity of electromagnetic wave is given by 1/√(μ∈). It is also known as phase velocity. The velocity of light is given by 3*10⁸ m/s.

27. The boundary condition at the surface of incidence obeys ________
a) Kepler’s law
b) Gauss law
c) Faraday law
d) Snell’s law
Answer: d
Explanation: Snell’s law is also known as Snell–Descartes law or the law of refraction. It gives a formula to describe the relationship between the angles of incidence and refraction, when referring to light or other waves passing through a boundary between two different isotropic media, such as water, glass, or air.

28. The angle at which no reflection occurs in the medium of origin is called _________
a) Azimuth angle
b) Elevation angle
c) Brewster angle
d) Inclination angle
Answer: c
Explanation: The Brewster angle is the angle at which no reflection occurs in the medium of origin. It occurs when the incident angle is such that the reflection coefficient is equal to zero. The critical Brewster’s angles for diamond, glass and water are 67.5°, 57° and 53° respectively.

29. Diffraction occurs when radio path between Tx. And Rx. Is obstructed by ____________
a) Surface having sharp irregularities
b) Smooth irregularities
c) Rough surface
d) All types of surfaces
Answer: a
Explanation: Diffraction occurs when radio path between transmitter and receiver is obstructed by a surface that has sharp irregularities (edges). The secondary waves resulting from the obstructing surface are present throughout the space and even behind the obstacle.

30. At high frequencies, diffraction does not depends on ___________
a) Geometry of the object
b) Distance between Tx and Rx
c) Amplitude of incident wave
d) Polarization of incident wave
Answer: b
Explanation: At high frequency, diffraction depends on the geometry of the object, as well as the amplitude, phase, and polarization of the incident wave at the point of diffraction. It gives rise to a bending of waves even when line of sight does not exist between transmitter and receiver.

31. Diffraction allows radio signals to propagate around ________
a) Continuous surface
b) Smooth surface
c) Curved surface of Earth
d) Does not allow propagation
Answer: c
Explanation: Diffraction allows radio signals to propagate around the curved surface of the Earth. Signals can propagate beyond the horizon and to propagate behind obstruction. It is the slight bending of light as it passes around the edge of an object.

32. Which principle explains the phenomenon of diffraction?
a) Principle of Simultaneity
b) Pascal’s Principle
c) Archimedes’ Principle
d) Huygen’s principle
Answer: d
Explanation: The phenomenon of diffraction can be explained by Huygen’s principle. It states that all points on a wavefront can be considered as point sources for the production of secondary wavelets. And these wavelets combine to produce a new wavefront in direction of propagation.

33. Diffraction is caused by propagation of secondary wavelets into _______
a) Bright region
b) Shadowed region
c) Smooth region
d) Large region
Answer: b
Explanation: Diffraction is caused due to propagation of secondary wavelets into a shadowed region. The field strength in the shadowed region is the vector sum of the electric field components of all the secondary wavelets in the space around the obstacle.

34. Difference between the direct path and the diffracted path is called _______
a) Average length
b) Radio path length
c) Excess path length
d) Wavelength
Answer: c
Explanation: Excess path length denoted by ∆, is the difference between the direct path and the diffracted path. It is calculated with the help of Fresnel zone geometry.

35. The phase difference between a direct line of sight path and diffracted path is function of _______
a) Height and position of obstruction
b) Only height
c) Operating frequency
d) Polarization
Answer: a
Explanation: The phase difference between a direct line of sight path and diffracted path is a function of height and position of the diffraction. It is also a function of transmitter and receiver location.

36. Which of the following explains the concept of diffraction loss?
a) Principle of Simultaneity
b) Pascal’s Principle
c) Fresnel zone
d) Archimedes’ Principle
Answer: c
Explanation: The concept of diffraction loss is a function of the path difference around an obstruction. It can be explained by Fresnel zones. Fresnel zones represent successive regions where secondary waves have a path length from Tx to Rx which are nλ/2 greater than total path length.

37. In mobile communication system, diffraction loss occurs due to ______
a) Dielectric medium
b) Obstruction
c) Electric field
d) Operating frequency
Answer: b
Explanation: Diffraction loss occurs from the blockage of secondary waves such that only a portion of the energy is diffracted around an obstacle. An obstruction causes a blockage of energy from source some of the Fresnel zones, allowing only some of the transmitted energy to reach the receiver.

38. For predicting the field strength in a given service area, it is essential to estimate ______
a) Polarization
b) Magnetic field
c) Height of transmitter
d) Signal attenuation
Answer: d
Explanation: Estimating the signal attenuation caused by diffraction of radio waves over hills and buildings is essential in predicting the field strength in a given service area. In practice, prediction is a process of theoretical approximation modified by necessary empirical corrections.

39. Empirical approach is based on fitting curve or analytical expressions.
a) True
b) False
Answer: a
Explanation: The empirical approach is based on fitting curves or analytical expressions that recreate a set of measured data. This has the advantage of implicitly taking into account all propagation factors, both known and unknown through actual field measurements.

40. Which of the following is not a practical path loss estimation technique?
a) Log distance path loss model
b) Log normal shadowing
c) Determination of percentage of coverage area
d) Hata model
Answer: d
Explanation: Log normal shadowing, log distance path loss model and determination of percentage of coverage area are practical pat loss estimation techniques. Hata model is only valid for exterior environment.

41. Average received signal power decreases __________ with distance.
a) Exponentially
b) Logarithmically
c) Two times
d) Four times
Answer: b
Explanation: Both theoretical and measurement based propagation models indicate that average received signal power decreases logarithmically with distance. It is valid for both outdoor and indoor channels.

42. What does path loss exponent indicates?
a) Rate at which path loss decreases with distance
b) Rate at which path loss increases with distance
c) Rate at which path loss decreases with power density
d) Rate at which path loss increases with power density
Answer: b
Explanation: The average large scale path loss for an arbitrary T-R separation is expressed as a function of distance by using a path loss exponent, n. It indicates the rate at which the path loss increases with distance.

43. The reference distance should not be in the far field of the antenna.
a) True
b) False
Answer: b
Explanation: It is important to select a free space reference distance that is appropriate for the propagation environment. The reference distance should always be in the far field of the antenna so that near field effects do not alter the reference path loss.

44. Which distribution describes the shadowing effect?
a) Log normal distribution
b) Nakagami distribution
c) Cauchy distribution
d) Rayleigh distribution
Answer: a
Explanation: Log normal distribution describes the random shadowing effects. It occurs over a large number of measurement locations which have the same T-R separation, but have different clutter on the propagation path.

45. Log normal shadowing is a phenomenon that occurs with same T-R separation having same level clutter on the propagation path.
a) True
b) False
Answer: b
Explanation: Log normal shadowing occurs over a large number of measurement locations which have the same T-R separation, but have different levels of clutter on the propagation path. It follows log normal distribution.

46. Log normal shadowing implies that measured signal levels at specific T-R separation have ______ distribution when signal levels have values in dB units.
a) Rayleigh
b) Gamma
c) Gaussian
d) Nakagami
Answer: c
Explanation: Log normal shadowing implies that measured signal levels at a specific T-R separation have Gaussian (Normal) distribution. It is about the distance dependent mean of 4.68 where the signal levels have values in dB units.

47. A link budget is accounting of all __________
a) Gain and losses from the transmitter
b) Power transmitted by transmitter
c) Power received by receiver
d) Power transmitted and received
Answer: a
Explanation: A link budget is accounting of all of the gains and losses from the transmitter, through the medium (free space, cable, waveguide, etc.) to the receiver in a telecommunication system. It accounts for the attenuation of the transmitted signal due to propagation, as well as the antenna gains and miscellaneous losses.

48. Antenna’s efficiency is given by the ratio of __________
a) Losses
b) Physical aperture to effective aperture
c) Signal power to noise power
d) Effective aperture to physical aperture
Answer: d
Explanation: The larger the antenna aperture the larger is the resulting signal power density in the desired direction. The ratio of effective aperture to the physical aperture is the antenna’s efficiency.

49. Which of the following is not an outdoor propagation model?
a) Longley-Rice model
b) Ericson Multiple Breakpoint Model
c) Hata model
d) Okumura model
Answer: b
Explanation: Ericson multiple breakpoint model is an indoor propagation model. Longley-Rice, Hata and Okumura model are outdoor propagation models. Most of these models are based on a systematic interpretation of measurement data obtained in the service area.

50. Longley –Rice model is applicable to _________
a) Point to point communication
b) All to all communication
c) Point to multipoint communication
d) Multipoint microwave distribution sstem
Answer: a
Explanation: The Longley-Rice model is applicable to point-to-point communication systems in the frequency range from 40 MHz to 100 GHz. They are applicable for different kinds of terrain. Terrain profile may vary from a simple curved Earth profile to a highly mountainous profile.

51. Longley-Rice prediction model is also referred as _________
a) Okumura model
b) Hata model
c) ITS irregular terrain model
d) Bertoni model
Answer: c
Explanation: The Longley Rice prediction model is also referred to as ITS irregular terrain model. The model is based on electromagnetic theory and on statistical analyses of both terrain features and radio measurements. It predicts the median attenuation of a radio signal as a function of distance and the variability of the signal in time and in space.

52. The extra term for additional attenuation due to urban clutter near the receiving antenna is called __________
a) Power factor
b) Urban gain
c) Clutter factor
d) Urban factor
Answer: d
Explanation: The urban factor (UF) is derived by comparing the predictions by the original Longley –Rice model with those obtained by Okumura. It deals with radio propagation in urban areas and is relevant to mobile radio.

53. Longley Rice model’s merit is to provide corrections due to environmental factors.
a) True
b) False
Answer: b
Explanation: One shortcoming of the Longley –Rice model is that it does not provide a way of determining corrections due to environmental factors. It does not consider correction factors to account for the effects of buildings and foliage. Multipath is also not considered.

54. Which method is used by Edwards and Durkin algorithm to calculate the loss associated with diffraction edges?
a) Epstein and Peterson method
b) Interpolation method
c) Knife edge diffraction method
d) Fresnel- Kirchoff method
Answer: a
Explanation: The Edwards and Durkin algorithm uses Epstein and Peterson method to calculate the loss associated with two diffraction edges. It is the sum of two attenuations. First is loss at second diffraction edge caused by first diffraction edge. And second is the loss at receiver caused by second diffraction edge.

55. Durkin’s model can read digital elevation map.
a) True
b) False
Answer: a
Explanation: Durkin’s model is very attractive because it can read in a digital elevation map and perform a site specific propagation computation on the elevation data. It can produce a signal strength contour that is reported to be good within a few dB.

56. Which of the most widely used model for signal prediction in urban areas?
a) Ericsson Multiple Breakpoint Model
b) Log distance path loss model
c) Okumura model
d) Attenuation factor model
Answer: c
Explanation: Okumura’s model is one of the most widely used models for signal prediction in urban areas. This model is applicable for frequencies in the range 150 MHz to 1920 MHz (Extrapolated upto 3000 MHz).

57. Okumura model is applicable for distances of _________
a) 1 m to 10 m
b) 1 km to 100 km
c) 100 km to 1000 km
d) 10 km to 10000 km
Answer: b
Explanation: Okumura’s model is applicable for distances of 1 km to 100 km. It can be used for base station antenna heights ranging from 30 m to 1000 m. Okumura developed a set of curves giving the median attenuation relative to free space in an urban area.

58. Okumura model is considered to be complex in predicting path loss.
a) True
b) False
Answer: b
Explanation: Okumura’s model is considered to be among the simplest and best in terms of accuracy in path loss prediction for mature cellular and land mobile radio system. It is very practical and has become a standard for system planning in modern land mobile system in Japan.

59. Which of the following is the major disadvantage of the Okumura model?
a) Complex
b) Inaccurate
c) Not practical
d) Slow response to rapid change in terrain
Answer: d
Explanation: The major disadvantage with the model is its slow response to rapid changes in terrain. Therefore the model is fairly good in urban and suburban areas, but not as good in rural areas. Common standard deviations between predicted and measured path loss values are 10 dB to 14 dB.

60. The Hata model is empirical formulation of which model?
a) Okumura model
b) Longley- Rice model
c) Durkin’s model
d) Walfisch and Bertoni model
Answer: a
Explanation: The Hata model is an empirical formulation of the graphical path loss data provided by Okumura. It is valid from 150 MHz to 1500 MHz. Hata presented the urban area propagation loss as a standard formulation. It supplied correct Equations for application to other situations.

61. Hata model is well suited for _________
a) Personal communication system
b) Large cell mobile radio system
c) Small cell mobile radio system
d) Every mobile radio system
Answer: b
Explanation: Hata model is well suited for large cell mobile radio systems. But it is not well suited for personal communication system (PCS) which have cells on the order of 1 km radius. Hata model does not have any path specific corrections which are available in Okumura model.

62. Which of the following considers the impact of rooftops and building?
a) Okumura model
b) Hata model
c) Walfisch and Bertoni model
d) Longley- Rice model
Answer: c
Explanation: The impact of rooftops and building height is considered by Walfisch and Bertoni model. It uses diffraction to predict average signal strength at street level. It considers path loss to be a product of three factors.

63. Small scale fading describes the _________ fluctuations of the amplitude, phases of a signal.
a) Rapid
b) Slow
c) Instantaneous
d) Different
Answer: a
Explanation: Small scale fading or simply fading, is used to describe the rapid fluctuations of amplitudes, phases, or multipath delays of a radio signal over a short period of time or travel distance. It ignores the large scale path loss.

64. Fading is caused by interference.
a) True
b) False
Answer: a
Explanation: Fading is caused by interference. It is caused by interference between two or more versions of the transmitted signal which arrive at the receiver at slightly different times.

65. Which of the following is not an effect caused by multipath in radio channel?
a) Rapid changes in signal strength
b) Random frequency modulation
c) Power of base station
d) Time dispersion
Answer: c
Explanation: Rapid changes in signal strength over a small travel distance are caused due to multipath. It causes random frequency modulation due to varying Doppler shifts on different multipath signals. Time dispersion is also caused by multipath propagation delays.

66. In urban areas, fading occurs due to height of mobile antenna ________ than height of surrounding structure.
a) Same
b) Smaller
c) Greater
d) Very larger
Answer: b
Explanation: In urban areas, fading occurs because height of the mobile antenna is below the height of surrounding structures. Therefore, there is no single line of sight path to the base station.

67. Fading does not occur when mobile receiver is stationary.
a) True
b) False
Answer: b
Explanation: The received signal may fade even when the mobile receiver is stationary. It is due to the movement of surrounding objects in the radio channel. The multipath components combine vectorially at the receiver antenna and cause signal to distort or fade.

68. Apparent shift in frequency in multipath wave is caused due to relative motion between________
a) Base station and MSC
b) Mobile and surrounding objects
c) Mobile and MSC
d) Mobile and base station
Answer: d
Explanation: Due to relative motion between mobile and base station, each multipath wave experiences an apparent shift in frequency. This shift in received signal frequency due to motion called Doppler shift.

69. Doppler shift is directly proportional to __________
a) Velocity
b) Height of antenna
c) Power of receiving antenna
d) Power of transmitter
Answer: a
Explanation: The shift in received signal frequency due to motion is called Doppler shift. It is directly proportional to the velocity and direction of motion of mobile with respect to the direction of arrival of the received multipath wave.

70. Which of the following factor does not influence small scale fading?
a) Multipath propagation
b) Power density of base station
c) Speed of mobile
d) Speed of surrounding objects
Answer: b
Explanation: Many physical factors in radio channel influence small scale fading. Multipath propagation, speed of mobile, speed of surrounding objects, transmission bandwidth of the signal influences small scale fading in a large way.

71. Signal will distort if transmitted signal bandwidth is greater than bandwidth of __________
a) Receiver
b) Radio channel
c) Multipath channel
d) Transceiver
Answer: c
Explanation: Received signal will be distorted if transmitted signal bandwidth is greater than bandwidth of multipath channel. But received signal strength will not fade much over a local area.

72. What is a measure of the maximum frequency difference for which signals are strongly correlated in amplitude?
a) Coherence bandwidth
b) Narrow bandwidth
c) Incoherent bandwidth
d) Wide bandwidth
Answer: a
Explanation: The bandwidth of the channel can be quantified by the coherence bandwidth. It is related to the specific multipath structure of channel. It is a measure of maximum frequency difference for which signals are strongly correlated in amplitude.

73. The Doppler shift for mobile moving with constant velocity, v is given by _______
a) (v*cos θ)/λ
b) v/λ
c) v*cos θ
d) v*λ
Answer: a
Explanation: Doppler shift is given by (v*cos θ)/λ. This formula relates the Doppler shift to the mobile velocity and spatial angle between the direction of motion of mobile and the direction of arrival of the wave.

74. Doppler shift is positive if mobile is moving away from direction of arrival of the wave.
a) True
b) False
Answer: b
Explanation: Doppler shift is positive if the mobile is moving toward the direction of arrival of the wave, as the apparent received frequency is increased. And if the mobile is moving away from the direction of arrival of the wave, Doppler shift is negative.

75. Which of the following distribution is used for describing statistical time varying nature of received envelope of multipath component?
a) Log normal distribution
b) Levy distribution
c) Rayleigh distribution
d) Gaussian distribution
Answer: c
Explanation: Rayleigh distribution is the most common distribution for statistical modelling. It is used to describe the statistical time varying nature of the received envelope of a flat fading signal. It also describes the envelope of an individual multipath component.

76. Envelope of the sum of two quadrature Gaussian noise signal obeys _________ distribution.
a) Rayleigh
b) Inverse Gaussian
c) Nakagami
d) Gamma
Answer: a
Explanation: It is well known that the envelope of the sum of two quadrature Gaussian noise signal obeys Rayleigh distribution. This fading distribution could be applied to any scenario where there is no line of sight path between transmitter and receiver antennas.

77. For a Rayleigh fading signal, mean and median differ by _______
a) 2 dB
b) 10 dB
c) 0.55 dB
d) 100 dB
Answer: c
Explanation: The mean and median differ by only 0.55 dB in a Rayleigh fading signal. The differences between the rms values and the other two values are higher.

78. It is easy to compare different fading distributions using mean values instead of median values.
a) True
b) False
Answer: b
Explanation: By using median values instead of mean values, it is easy to compare different fading distributions which may have widely varying means. Median is used in practice since fading data is measured in the field and a particular distribution cannot be assumed.

79. For a nonfading signal component present, the small scale fading envelope distribution is ____________
a) Rayleigh
b) Gaussian
c) Log normal
d) Ricean
Answer: d
Explanation: The small scale fading envelope is Ricean when there is a dominant stationary (nonfading) signal component, such as line of sight propagation path. In such a situation, random multipath components arriving at different angles are superimposed on a stationary dominant signal.

80. Ricean distribution degenerates to ________ distribution when the dominant component fades away.
a) Log normal
b) Gamma
c) Rayleigh
d) Gaussian
Answer: c
Explanation: Ricean distribution degenerates to Rayleigh distribution when the dominant component fades away. As the dominant signal becomes weaker, the composite signal resembles a noise signal which has an envelope that is Rayleigh.

81. The envelope of a bandpass noise is __________
a) Uniformly distributed
b) Rayleigh
c) Ricean
d) Gaussian
Answer: b
Explanation: The envelope of only bandpass noise is Rayleigh distribution. Rayleigh distribution is a continuous probability density function for positive random variables.

82. The envelope of a sinusoid plus bandpass noise has __________
a) Uniformly distributed
b) Rayleigh
c) Ricean
d) Gaussian
Answer: c
Explanation: The envelope of a sinusoid plus bandpass noise has Ricean distribution. In probability theory, Ricean distribution is the probability distribution which has magnitude of a circular bivariate normal random variable with potentially non-zero mean.

83. What do you call an attenuation that occurs over many different wavelengths of the carrier?
a) Rayleigh fading
b) Ricean fading
c) Wavelength fading
d) Slow fading
Answer: d
Explanation: Slow fading does not vary quickly with the frequency. It originates due to effect of mobility. Slow fading is the result of signal path change due to shadowing and obstructions such as tree or buildings etc.

84. Which of the reception problems below that is not due to multipath?
a) Delayed spreading
b) Rayleigh fading
c) Random Doppler shift
d) Slow fading
Answer: d
Explanation: Slow fading arises when the coherence time of the channel is large relative to the delay requirement of the application. Slow fading is caused by events such as shadowing, where a large obstruction such as a hill or large building obscures the main signal path between the transmitter and the receiver.

1. Which of the following is the world’s first cellular system to specify digital modulation and network level architecture?
a) GSM
b) AMPS
c) CDMA
d) IS-54
Answer: a
Explanation: GSM was the world’s first cellular system to specify digital modulation and level architectures and services. It is the world’s most popular 2G technology. It was developed to solve the fragmentation problems of the first cellular systems in Europe.

2. Previously in 1980s, GSM stands for ____________
a) Global system for mobile
b) Groupe special mobile
c) Global special mobile
d) Groupe system mobile
Answer: b
Explanation: In the mid-1980s GSM was called by the name Groupe special mobile. In 1992, GSM changed its name to Global System for Mobile Communication for marketing reasons.

3. Who sets the standards of GSM?
a) ITU
b) AT & T
c) ETSI
d) USDC
Answer: c
Explanation: The setting of standards for GSM is under the aegis of the European Technical Standards Institute (ETSI). GSM task was to specify a common mobile communication system for Europe in the 900 MHZ band.

4. Which of the following does not come under the teleservices of GSM?
a) Standard mobile telephony
b) Mobile originated traffic
c) Base originated traffic
d) Packet switched traffic
Answer: d
Explanation: GSM services follow ISDN guidelines and are classified as either teleservices or data services. Teleservices include standard mobile telephony and mobile originated or base originated traffic.

5. Which of the following comes under supplementary ISDN services?
a) Emergency calling
b) Packet switched protocols
c) Call diversion
d) Standard mobile telephony
Answer: c
Explanation: Supplementary ISDN services are digital in nature. They include call diversion, closed user groups, and caller identification, and are not available in analog mobile networks. Supplementary services also include short messaging service (SMS).

6. Which of the following memory device stores information such as subscriber’s identification number in GSM?
a) Register
b) Flip flop
c) SIM
d) SMS
Answer: c
Explanation: SIM (subscriber identity module) is a memory device that stores information such as the subscriber’s identification number, the networks and countries where the subscriber is entitled to service, privacy keys, and other user specific information.

7. Which of the following feature makes impossible to eavesdrop on GSM radio transmission?
a) SIM
b) On the air privacy
c) SMS
d) Packet switched traffic
Answer: b
Explanation: The on the air privacy feature of GSM makes impossible to eavesdrop on a GSM radio transmission. The privacy is made possible by encrypting the digital bit stream sent by a GSM transmitter, according to a specific secret cryptographic key that is known only to the cellular carrier.

8. Which of the following does not come under subsystem of GSM architecture?
a) BSS
b) NSS
c) OSS
d) Channel
Answer: d
Explanation: The GSM architecture consists of three major interconnected subsystems that interact between themselves and with the users through certain network interfaces. The subsystems are BSS (Base Station Subsystem), NSS (Network and Switching Subsystem) and OSS (Operation Support Subsystem).

9. Which of the following subsystem provides radio transmission between mobile station and MSC?
a) BSS
b) NSS
c) OSS
d) BSC
Answer: a
Explanation: The BSS provides and manages radio transmission paths between the mobile stations and the Mobile Switching Center (MSC). It also manages the radio interface between the mobile stations and all other subsystems of GSM.

10. ___________ manages the switching function in GSM.
a) BSS
b) NSS
c) OSS
d) MSC
Answer: b
Explanation: NSS (Network and Switching Subsystem) manages the switching functions of the system. It allows the MSCs to communicate with other networks such as PSTN and ISDN.

11. __________ supports the operation and maintenance of GSM.
a) BSS
b) NSS
c) OSS
d) MSC
Answer: c
Explanation: The OSS (Operation Support Subsystem) supports the operation and maintenance of GSM. It allows system engineers to monitor, diagnose, and troubleshoot all aspects of GSM.

12. __________ carries digitally encoded user data.
a) Traffic channels
b) Control channels
c) Signalling channels
d) Forward channels
Answer: a
Explanation: Traffic channels carry digitally encoded user speech or user data. It has identical functions and formats on both the forward and reverse links.

13. ____________ carries signalling and synchronizing commands.
a) Traffic channels
b) Control channels
c) Signalling channels
d) Forward channels
Answer: b
Explanation: Control channels carry signalling and synchronizing commands between the base station and mobile station. Certain types of control channels are defined for just the forward or reverse link.

14. Which of the following is not a control channel of GSM?
a) BCH
b) CCCH
c) DCCH
d) TCH
Answer: d
Explanation: There are three main control channels in the GSM system. These are the broadcast channel (BCH), the common control channel (CCCH) and the dedicated control channel (DCCH). Each control channel consists of several logical channels.

15. Which of the following is the forward control channel that is used to broadcast information?
a) BCCH
b) CCCH
c) DCCH
d) TCH
Answer: a
Explanation: The broadcast control channel (BCCH) is a forward channel that is used to broadcast information such as cell and network identity, and operating characteristics of the cell.

16. Which of the following channel does not come under CCCH?
a) PCH
b) RACH
c) DCCH
d) AGCH
Answer: c
Explanation: CCCH consists of three different channels. They are paging channel (PCH), which is a forward link channel, the random access channel (RACH) which is a reverse link channel, and the access grant channel (AGCH) which is a forward link channel.

17. Which of the following channel provides paging signals from base station to all mobiles in the cell?
a) RACH
b) AGCH
c) DCCH
d) PCH
Answer: d
Explanation: The PCH provides paging signals from the base station to all mobiles in the cell. It notifies a specific mobile of an incoming call which originates from the PSTN.

18. ___________ is a reverse link channel used by a subscriber unit to acknowledge.
a) RACH
b) AGCH
c) DCCH
d) PCH
Answer: a
Explanation: The RACH (Random Access Channel) is a reverse link channel used by a subscriber unit to acknowledge a page from the PCH. It is also used by mobiles to originate a call.

19. Which of the following channel is used by base station to provide forward link communication to mobile?
a) RACH
b) AGCH
c) DCCH
d) PCH
Answer: b
Explanation: The AGCH (Access Grant Channel) is used by the base station to provide forward link communication to the mobile. It carries data which instructs the mobile to operate in a particular physical channel with particular dedicated control channel.

20. Which of the following burst is used to broadcast the frequency and time synchronization control messages?
a) FCCH and SCH
b) TCH and DCCH
c) RACH and TCH
d) FCCH and DCCH
Answer: a
Explanation: FCCH and SCH burst are used to broadcast the frequency and time synchronization control messages. They are used in TS0 of specific frames.

21. Which of the following burst is used to access service from any base station?
a) TCH
b) RACH
c) SCH
d) FCCH
Answer: b
Explanation: Each user transmits a burst of data during the time slot assigned to it. The RACH burst is used by all mobiles to access service from any base station, and dummy burst is used as filter information for unused timeslots on forward link.

22. Group of superframes in GSM is called multiframe.
a) True
b) False
Answer: b
Explanation: Each of the normal speech frames are grouped into larger structures called multiframes. These multiframes are grouped into superframes and hyperframes.

23. US digital cellular system based on CDMA was standardized as ________
a) IS-54
b) IS-136
c) IS-95
d) IS-76
Answer: c
Explanation: A US digital cellular system based on CDMA was standardized as Interim Standard 95 (IS-95). It was standardized by US Telecommunication Industry Association (TIA) and promised increased capacity.

24. IS-95 was not compatible with existing AMPS frequency band.
a) True
b) False
Answer: b
Explanation: Like IS-136, IS-95 system was designed to be compatible with the existing US analog cellular system (AMPS) frequency band. Hence, mobile and base stations can be economically produced for dual mode operation.

25. Which of the following is used by IS-95?
a) DSSS
b) FHSS
c) THSS
d) Hybrid
Answer: a
Explanation: IS-95 uses a direct sequence spread spectrum CDMA system. It allows each user within a cell to use the same radio channel, and users in adjacent cell also use the same radio channel.

26. Each IS-95 channel occupies ___________ of spectrum on each one way link.
a) 1.25 MHz
b) 1.25 kHz
c) 200 kHz
d) 125 kHz
Answer: a
Explanation: To facilitate graceful transition from AMPS to CDMA, each IS-95 channel occupies 1.25 MHz of spectrum on each one way link, or 10% of the available cellular spectrum for a US cellular provider.

27. IS-95 uses same modulation technique for forward and reverse channel.
a) True
b) False
Answer: b
Explanation: IS-95 uses different modulation and spreading technique for the forward and reverse links. On the forward link, the base station simultaneously transmits the user data for all mobiles in the cell by using different spreading sequence for each mobile.

28. IS-95 is specified for reverse link operation in _________ band.
a) 869-894 MHz
b) 849-894 MHz
c) 849-869 MHz
d) 824-849 MHz
Answer: d
Explanation: IS-95 is specified for reverse link operation in the 824-849 MHz band and 869-894 MHz for the forward link. The PCS version of IS-95 has also been designed for international use in the 1800-2000 MHz bands.

29. User data in IS-95 is spread to a channel chip rate of ________
a) 1.2288 Mchip/s
b) 9.6 Mchip/s
c) 12.288 Mchip/s
d) 0.96 Mchip/s
Answer: a
Explanation: User data is spread to a channel chip rate of 1.2288 Mchip/s (a total spreading factor of 128) using a combination of techniques. The spreading process is different for the forward and reverse links in the original CDMA specification.

30. __________ are used to resolve and combine multipath components.
a) Equalizer
b) Registers
c) RAKE receiver
d) Frequency divider
Answer: c
Explanation: At both the base station and the subscriber, RAKE receivers are used to resolve and combine multipath components, thereby reducing the degree of fading. A RAKE receiver exploits the multipath time delays in a channel and combines the delayed replicas of transmitted signal.

31. CT2 was the first generation of cordless telephones.
a) True
b) False
Answer: b
Explanation: CT2 was the second generation of cordless telephones introduced in Great Britain in 1989. It is used to provide telepoint services which allow a subscriber to use CT2 handsets at a public telepoint.

32. CT2 is analog version of first generation cordless telephones.
a) True
b) False
Answer: b
Explanation: CT2 is a digital version of the first generation, analog, cordless telephones. When compared with analog cordless phones, CT2 offers good speech quality and is more resistant to interference.

33) GPRS stands for?
A) General Packet Repair Service
B) General Packet Radio Service
C) Graphics Packet Radio Service
D) None
Answer: B

34) What is the data rate or speed offered by a GPRS connection?
A) 56-115kbps
B) 9-256kbps
C) 64-128kbps
D) None
Answer: A

35) GPRS services belong to which generation?
A) 1G
B) 2G
C) 3G
D) 4G
Answer: B

36) Choose a correct abbreviation below.
A) SGSN – Serving GPRS Support Node
B) GGSN – Gateway GPRS Support Node
C) IP – Internet Protocol
D) All
Answer: D

37) Choose a correct Abbreviation below.
A) PCU – Packet Control Unit
B) CG – Charging Gateway
C) BG – Border Gateway
D) All
Answer: D

38) Choose a correct Abbreviation below.
A) PCU – Packet Control Unit
B) CCU – Channel Codec Unit
C) GTP – GPRS Tunneling Protocol
D) All
Answer: D

39) GPRS is a Connection Oriented service. True/False?
A) False
B) True
C) –
D) –
Answer: A

40) GPRS is a Circuit Switched Data (CSD) service. True/False?
A) False
B) True
C) –
D) –
Answer: A

41) GPRS uses which unused channels for transportation of Data in general?
A) SDCCH
B) BCCH
C) TCH
D) SCH
Answer: C

42) Type-A Mobile Station supports ________.
A) Only Speech
B) Only Data
C) Speech and Data Simultaneously
D) Speech or Data one at a time.
Answer: C

43. GSM corresponds to which generation?
A) 1G
B) 1.5G
C) 2G
D) 3G
Answer(C)

44. What is the type signalling between Mobile Station and Base Transceiver Station in a 2G technology?
A) Analog
B) Digital
C) Discrete
D) Dampened
Answer(B)

45. GSM stands for?
A) Global System for Mobile Communication
B) Global Service for Mobile Communication
C) Geo Synchronous Mobile Communication
D) None of the above
Answer(A)

46. GSM technology was a standard developed by ?
A) United Kingdom
B) United States
C) Europe
D) Australia
Answer(C)

47. Who developed standards for GSM technology?
A) ANSI – American National Standards Institute
B) ETSI – European Telecommunications Standards Institute
C) IEEE – Institute of Electrical and Electronics Engineers
D) None of the above
Answer(B)

48. Data service started or offered by 2G GSM technology is?
A) GPRS
B) EDGE
C) H
D) A and B
Answer(D)

49. GPRS stands for ?
A) General Packet Radio Service
B) General Packet Radio Pilot
C) Generation Pilot Radio Service
D) None of the above
Answer(A)

50. EDGE stands for?
A) Enhanced Data Rate for GSM Evolution
B) Enhanced Data for GSM
C) Enhanced Data for GSM Enhanced
D) None of the above
Answer(A)

51. EDGE services are considered as _____ generation services.
A) 2G
B) 2.5G
C) 3G
D) None of the above
Answer(B)

52. Which country deployed the first GSM network?
A) USA
B) UK
C) France
D) Finland
Answer(D)

53. The type of switching used in a GSM network is _____?
A) Circuit Switching
B) Packet Switching
C) A and B
D) None
Answer(C)

54. Which is the non European country operator to deploy GSM services?
A) AT&T
B) NTT
C) Telecom Australia
D) Docomo
Answer(C)

55. The world’s first GSM call was made on?
A) 1990 July 1st
B) 1991 July 1st
C) 1992 July 1st
D) 1993 July 1st
Answer(B)

56. When did FAX, Data and SMS services in GSM network launch?
A) 1991
B) 1995
C) 1997
D) 2000
Answer(B)

57. Commercial GPRS enabled handsets or mobiles were launched in ______ year for the first time.
A) 1995
B) 1997
C) 2000
D) 2003
Answer(C)

58. Choose frequency band that was chosen to operate a GSM Network?
A) 900MHz
B) 1800MHz
C) 850, 1900MHz
D) All the above
Answer(D)

59. Which is first operator to shutdown 2G or GSM services completely?
A) AT&T
B) TELSTRA, Australia
C) NTT, Japan
D) Vodafone, UK
Answer(B)

60. Cryptographic algorithms used by GSM technology are ______?
A) A5/1
B) A5/2
C) A5/3
D) All the above
Answer(D)

61. GPRS Encryption algorithms are ______ ?
A) GEA/1
B) GEA/2
C) GEA/3
D) All the above
Answer(D)

62. Which frequency band supports more coverage area in a GSM or 2G network?
A) 1900MHz
B) 1800MHz
C) 900MHz
D) None of the above
Answer(C)

63. The 2G cellular network uses
a. TDMA/FDD
b. CDMA/ FDD
c. Digital modulation formats
d. All of the above
ANSWER: d

64. NADC is a 2G standard for
a. TDMA
b. CDMA
c. None of the above
ANSWER: a

65. 2G CDMA standard – cdmaone supports up to
a. 8 users
b. 64 users
c. 32 users
d. 116 users
ANSWER: b

66. 2G standards support
a. Limited internet browsing
b. Short messaging service
c. Both a) and b)
d. None of the above
ANSWER: c

67. The 2G GSM technology uses a carrier separation of
a. 1.25 MHz
b. 200 KHz
c. 30 KHz
d. 300 KHz
ANSWER: b

1. Which of the following is not a characteristic of 3G network?
a) Communication over VoIP
b) Unparalleled network capacity
c) Multi-megabit Internet access
d) LTE based network
Answer: d
Explanation: Multi-megabit Internet access, communication using Voice over internet Protocol (VoIP), voice activated calls, unparalleled network capacity are some of the characteristics of 3G network. 3G systems promise unparalleled wireless access which is not possible in 2G systems. LTE (Long term Evolution) is a standard of 4G systems.

2. What is the term used by ITU for a set of global standards of 3G systems?
a) IMT 2000
b) GSM
c) CDMA
d) EDGE
Answer: a
Explanation: International Telecommunications Union (ITU) used the term IMT-2000 in 1998. It is used for a set of global standards for third generation (3G) mobile telecoms services and equipment.

3. Which of the following leads to evolution of 3G networks in CDMA systems?
a) IS-95
b) IS-95B
c) CdmaOne
d) Cdma2000
Answer: d
Explanation: 3G evolution of CDMA system leads to cdma2000. It is based on the fundamentals of IS-95 and IS-95B. IS-95 is a 2G standard for CDMA systems. IS-95B is a CDMA system for 2.5G networks.

4. Which of the following leads to the 3G evolution of GSM, IS-136 and PDC systems?
a) W-CDMA
b) GPRS
c) EDGE
d) HSCSD
Answer: a
Explanation: The 3G evolution for GSM, IS-136 and PDC systems leads to W-CDMA (Wideband CDMA). It is based on the network fundamentals of GSM, as well as merged versions of GSM and IS-136 through EDGE. GPRS, EDGE and HSCSD are 2.5G networks.

5. What is 3GPP?
a) Project based on W-CDMA
b) Project based on cdma2000
c) Project based on 2G standards
d) Project based on 2.5G standards
Answer: a
Explanation: 3GPP is a 3G Partnership Project for Wideband CDMA standards based on backward compatibility with GSM and IS-136. The project was established in December 1998. Its initial scope was to make a globally applicable third generation mobile phone system.

6. What is 3GPP2?
a) Project based on W-CDMA
b) Project based on cdma2000
c) Project based on 2G standards
d) Project based on 2.5G standards
Answer: b
Explanation: 3GPP2 is a 3G Partnership Project for Cdma2000 standards based on backward compatibility with earlier CdmaOne 2G CDMA technology. It was initiated by IMT-2000 to cover high speed, broadband and Internet Protocol (IP) based mobile systems. It mainly focuses on North American and Asian regions.

7. Which of the following is not a standard of 3G?
a) UMTS
b) Cdma2000
c) TD-SCDMA
d) LTE
Answer: d
Explanation: UMTS (Universal Mobile Telecommunication System), TD-SCDMA (Time Division Synchronous Code Division Multiple Access), Cdma2000 are the standards defined for 3G networks. LTE (Long Term Evolution) is a 4G standard for high speed wireless communication.

8. Which of the following 3G standard is used in Japan?
a) Cdma2000
b) TD-SCDMA
c) UMTS
d) UTRA
Answer: c
Explanation: Japan uses UMTS (W-CDMA) standard for its 3G network. The standards used are UMTS 800, UMTS 900, UMTS 1500, UMTS 1700 and UMTS 2100. They are standardized by ARIB (Association of Radio industries and Business).

9. What does the number 2000 in IMT-2000 signifies?
a) Year
b) Number of subscribers per cell
c) Number of cells
d) Area (Km)
Answer: a
Explanation: The International Telecommunication Union (ITU) defined the third generation (3G) of mobile telephony standards, IMT-2000 to facilitate growth, increase bandwidth, and support more diverse applications. The number 2000 in IMT-2000 indicates the start of the system (year 2000) and the spectrum used (around 2000 MHz).

10. Which of the following is not an application of third generation network?
a) Global Positioning System (GPS)
b) Video conferencing
c) Mobile TV
d) Downloading rate upto 1 Gbps
Answer: d
Explanation: 3G applications include GPS (Global Positioning System), MMS (Multimedia Messaging System), video conferencing, location based services, video on demand, wireless voice telephony and high data rates with peak downloading rate of 100 Mbps. For 4G networks, the peak downloading rate is 1 Gbps.

11. What is the full form of UMTS?
a) Universal Mobile Telephone System
b) Ubiquitous Mobile Telephone System
c) Ubiquitous Mobile Telemetry System
d) Universal Machine Telemedicine System
Answer: a
Explanation: UMTS (Universal Mobile Telephone System) is a visionary air interface standard that was introduced in 1996. European carriers, manufacturers, and government regulators collectively developed the early version of UMTS as an open air interface standard for third generation wireless telecommunication.

12. UMTS use which multiple access technique?
a) CDMA
b) TDMA
c) FDMA
d) SDMA
Answer: a
Explanation: Although UMTS is designed to operate on evolved GSM core networks, it uses code division multiple access (CDMA) for its air interface. The majority of the 3G systems in operation employ CDMA, while the rest use TDMA. CDMA allows various users to share a channel at the same time, while TDMA allows users to share the same channel by chopping it into different time slots.

13. UMTS does not has backward compatibility with ____________
a) GSM
b) IS-136
c) IS-95
d) GPRS
Answer: c
Explanation: UMTS assures backward compatibility with the second generation GSM, IS-136 and PDC TDMA technologies. It is also compatible with all 2.5G TDMA techniques like GPRS and EDGE. But it does not provide compatibility to CDMA technologies of 2G and 2.5 G. IS-95 is a CDMA standard of 2G.

14. UMTS is also known as _____________
a) IS-95
b) GPRS
c) CdmaOne
d) W-CDMA
Answer: d
Explanation: UMTS uses Wideband CDMA (W-CDMA) to carry the radio transmissions. Therefore, it is also referred as W-CDMA. W-CDMA offers greater spectral efficiency and bandwidth to mobile network operators.

15. What is the chip rate of W-CDMA?
a) 1.2288 Mcps
b) 3.84 Mcps
c) 270.833 Ksps
d) 100 Mcps
Answer: b
Explanation: W-CDMA uses a chip rate of 3.84 Mcps. Chip rate is the product of symbol rate and spreading factor. If the symbol rate is 960 Kbps and spreading factor is 4 for W-CDMA, then the chip rate is 3.84 Mcps. The chip rate for Cdma2000 and GSM are 1.2288 Mcps and 27.0833 Ksps respectively.

16. W-CDMA works in FDD mode only.
a) True
b) False
Answer: b
Explanation: W-CDMA works in both FDD and TDD mode. W-CDMA developed for wide area cellular coverage uses FDD. And TDD is used by W-CDMA for indoor cordless type applications.

17. How much packet data rate per user is supported by W-CDMA if the user is stationary?
a) 2.048 Kbps
b) 100 Mbps
c) 2.048 Mbps
d) 1 Gbps
Answer: c
Explanation: If the user is stationary, W-CDMA supports packet data rates upto 2.048Mbps per user. Thus, it allows high quality data, multimedia, streaming audio video and broadcast type services to consumers. Future version of WCDMA will support stationary user data rates in excess of 8Mbps.

18. What is the minimum spectrum allocation required by W-CDMA?
a) 5 MHz
b) 20MHz
c) 1.25 MHz
d) 200 KHz
Answer: a
Explanation: W-CDMA/UMTS requires a minimum spectrum allocation of 5 MHz. Using this bandwidth, it has the capacity to carry over 100 simultaneous voice calls. It is able to carry data at speeds up to 2 Mbps in its original format. 20 MHz is the bandwidth defined for LTE. CdmaOne uses a bandwidth of 1.25 MHz. GSM’s bandwidth is 200 KHz.

19. W-CDMA requires a complete change of RF equipment at each base station.
a) True
b) False
Answer: a
Explanation: W-CDMA is designed to provide backward compatibility and interoperability for all GSM, IS-136/PDC, GPRS and EDGE equipment. But due to a wider air interface bandwidth of W-CDMA, it requires a complete change of RF-equipment at each base station.

20. How much increase in spectral efficiency is provided by W-CDMA in comparison to GSM?
a) Two times
b) Three times
c) No increase
d) Six times
Answer: d
Explanation: W-CDMA can provide at least six times an increase in spectral efficiency over GSM at system level. Such a wider bandwidth is chosen to higher data rates as low as 8 kbps to as high as 2 Mbps on a single 5 MHz W-CDMA radio channel.

21. Which of the following has no backward compatibility with 3G Cdma2000?
a) IS-95
b) GPRS
c) IS-95A
d) IS-95B
Answer: b
Explanation: 3G Cdma2000 is based on the original IS-95 and IS-95A CDMA standards, as well as the 2.5G IS-95B air interface. While upgrading, Cdma2000 maintains backward compatibility with existing IS-95, IS-95A and IS-95B equipments. Thus, Cdma2000 allow wireless carriers to introduce a family of new high data rate Internet access capabilities within existing systems.

22. 2G and 2.5G CDMA operators may selectively introduce 3G capabilities at each cell without changing entire base stations and reallocate spectrums.
a) True
b) False
Answer: a
Explanation: Cdma2000 does not require change in entire base station or additional RF equipment. All the changes are made in software or in baseband hardware.

23. Which of the following the first 3G CDMA air interface?
a) IS-95
b) IS-95B
c) Cdma2000 1xRTT
d) CdmaOne
Answer: c
Explanation: Cdma2000 1xRTT is the first 3G air interface. Here, RTT stands for Radio Transmission Technology and 1x indicates that the bandwidth is one times that of the original CdmaOne channel. It is modulated on a single carrier.

24. Within ITU IMT-2000 body, Cdma2000 1xRTT is also known as ____________
a) Cdma2000 1xEV-DO
b) Cdma2000 1xEV-DV
c) IS-95B
d) G3G-MC-CDMA-1X
Answer: d
Explanation: Cdma2000 1xRTT is also known as G3G-MC-CDMA-1X. The initials MC stand for multicarrier. RTT stand for Radio Transmission Technology, a language suggested by IMT-2000 body. Usually, MC and RTT are omitted for convenience.

25. How many users are supported by Cdma2000 1X in comparison to 2G CDMA standard?
a) Half
b) Twice
c) Six times
d) Ten times
Answer: b
Explanation: Cdma2000 support up to twice as many users as the 2G CDMA standard. It also provides the two times the standby time for longer lasting battery life.

26. Cdma2000 works in TDD mode only.
a) True
b) False
Answer: b
Explanation: Cdma2000 works in both FDD and TDD mode. Cdma2000 developed for wide area cellular coverage uses FDD. And TDD is used by Cdma2000 for indoor cordless type applications.

27. Which of the following is not a characteristic of Cdma2000?
a) Adaptable baseband signalling rates
b) Adaptable baseband chipping rates
c) Multicarrier technologies
d) OFDMA
Answer: d
Explanation: Cdma2000 does not use OFDMA technique. OFDMA is used by 4G networks. Cdma2000 uses rapidly adaptable baseband signalling rates and chipping rates for each user. It also provides multi-level keying within same framework.

28. Cdma2000 1xEV was developed by ________
a) Motorola
b) AT&T Laboratories
c) Qualcomm
d) NTT
Answer: c
Explanation: Cdma2000 is an evolutionary advancement for CDMA. It was developed by Qualcomm Inc. It is a proprietary high data rate (HDR) packet standard that can be overlaid upon existing IS-95, IS-95B and Cdma2000 networks.

29. How is bandwidth increased in Cdma2000?
a) Clubbing adjacent radio channels
b) Changing the hardware of base stations
c) Change of spectrum
d) Change of RF equipment
Answer: a
Explanation: The increase in the bandwidth is achieved through clubbing the adjacent radio channels of CdmaOne and using multicarrier technologies. For example, Cdma2000 3xRTT uses these technologies by combining three adjacent 1.25 MHz bandwidth of CdmaOne channels.

30. What are the two options provided by Cdma2000 1xEV?
a) Cdma2000 1xRTT. Cdma2000 3xRTT
b) Cdma2000 1xEV-DO, Cdma2000 1xEV-DV
c) Cdma2000 1xEV-DT, Cdma2000 1xEV-DO
d) Cdma2000 1xRTT, Cdma2000 1xEV-DV
Answer: b
Explanation: Cdma2000 1xEV is an evolutionary upgrade for Cdma2000. It provides two options, for accessing only data (Cdma2000 1xEV-DO) and for both data & voice (Cdma2000 1xEV-DV).

31. Which of the following is not backward compatible with Cdma2000?
a) Cdma2000 1xRTT
b) Cdma2000 3xRTT
c) Cdma2000 1xEV-DO
d) Cdma2000 1xEV-DT
Answer: c
Explanation: Cdma2000 1xEV-DO option provides data rates of about 2.4 Mbps and supports data traffic only. No voice communication is supported. It relaxes the minimum latency requirement. But this mode is not backward compatible with Cdma2000.

32) What is the minimum data speed offered by 3G mobile technology for a Stationary user?
A) 128kbps
B) 384 kbps
C) 2 mbps
D) 8 mbps
Answer:C

33) What is the minimum data speed offered by 3G mobile technology to a Slow Moving user?
A) 128 kbps
B) 384 kbps
C) 2 mbps
D) 8Mbps
Answer:B

34) What is the minimum speed offered by 3G mobile technology to a Fast moving user?
A) 128 Kbps
B) 384 Kbps
C) 2 Mbps
D) 8 Mbps
Answer:A

35) WCDMA stands for?
A) Wide array CDMA
B) Wide band CDMA
C) Wireless CDMA
D) Wifi CDMA
Answer:B

36) What is the Multiple Access technique used in a 3G mobile network.
A) Time Division
B) Frequency Division
C) Code Division
D) None
Answer:C

37) SIM in a 3G network is called _____?
A) Micro SIM
B) Nano SIM
C) USIM
D) RSIM
Answer:C

38) What are the parts of a 3G network architecture?
A) User Equipment (UE)
B) Radio Access Network (RAN)
C) Core Network
D) All the above. UE, RAN and Core network.
Answer:D

39) What is the name of a BTS in a 3G mobile network?
A) Structure
B) Node-B
C) Node-N
D) None
Answer:B

40) What is the name of BSC equivalent part in a 3G mobile network?
A) Controller
B) Radio Switch Controller
C) Radio Network Controller
D) Radio Command Center
Answer:C

41) What is the equivalent interface Um(Air interface) in a 3G network?
A) Un
B) Us
C) Uu
D) Uc
Answer:C

42) What is the interface between USIM and ME(Mobile Equipment)?
A) Cm
B) Cn
C) Cu
D) Cc
Answer:C

43) What is the interface between NodeB and RNC in a WCDMA network?
A) Lub
B) Luc
C) Lud
D) Lue
Answer:A

44) What is the interface between RNC and MGW (Media Gateway)?
A) Lc
B) Ln
C) Lu
D) None
Answer:C

45) What is the interface between RNC and SGSN?
A) Lu
B) Lc
C) Lm
D) None
Answer:A

46) What is the interface between MGW and EIR?
A) A interface
B) F interface
C) B interface
D) None
Answer:B

47) What is the interface between MGW and HLR?
A) A interface
B) B interface
C) D interface
D) F interface
Answer:C

48) A UMTS(Universal Mobile Telecommunication) network is a ___ network.
A) First Generation
B) Second Generation
C) Third Generation
D) Fourth Generation
Answer:C

49) Who developed standards for a UMTS network?
A) ANSI (American National Standards Institute)
B) 3GPP (3rd Generation Partnership Project)
C) ITU (International Telecommunication Union)
D) None
Answer:B

50) What is the maximum data rate supported by a 3G network or UMTS network?
A) 384 kbps
B) 2 Mbps
C) 32 Mbps
D) 42 Mbps
Answer:D

51) CDMA2000 technology is also a ___ network.
A) 2G
B) 3G
C) 4G
D) None
Answer:B

52) CDMA is a ___ generation technology.
A) 1st generation
B) 2nd generation
C) 3rd generation
D) 4th generation
Answer:B

53) What is the abbreviation of CDMA?
A) Code Digital Multiple Access
B) Code Duplex Multiple Access
C) Code Division Multiple Access
D) None
Answer:C

54) 2G CDMA is also called?
A) IS-95
B) CDMAOne
C) 1st Generation CDMA
D) All the above
Answer:D

55) A CDMA2000 is a ____ generation network.
A) First Generation
B) Second Generation
C) Third Generation
D) Fourth Generation
Answer:C

56) CDMA2000 uses ___ radio system.
A) Analog
B) Digital
C) Analog and Digital
D) None
Answer:B

57) What is another name for a CDMA2000 network?
A) IS-2000
B) C2K
C) IMT Multi-Carrier (IMT-MC)
D) All the above
Answer:D

58) Who developed standards for a CDMA2000 3G network system?
A) ANSI (Americal National Standards Institute)
B) 3GPP (Third Generation Partnership Projects)
C) 3GPP-2
D) GSM
Answer:C

59) What are the Evolution stages or versions of a CDMA2000 3G network?
A) CDMA2000 1xRTT
B) CDMA2000 1x Advanced
C) CDMA2000 1xEV-DO
D) All the above
Answer:D

60) The voice capacity of a CDMA2000 1xRTT over CDMAOne is ____.
A) The same
B) 2 times more
C) 4 times more
D) None
Answer:B

61) What are the advancements in the CDMA2000 over CDMAOne technology?
A) More Battery Life
B) Frequency Band Flexibility
C) Higher Capacity for Voice and Data
D) All
Answer:D

62) State TRUE or FALSE. An IS-95 compatible Handset works in IS-2000(CDMA2000) network without any problem.
A) False
B) True
Answer:B

63) What are the new features of CDMA2000 3G network?
A) Fast power control (saves battery and reduces delay)
B) Support for Radio Configurations(RC) from RC1 to RC9 in forward link and RC1 to RC6 in Reverse Link for flexible Rate, Spreading Rate, Channel Coding and Diversity.
C) Support for R-UIM (Removable SIM)
D) All
Answer:D

64) In a CDMA2000 network, support for EVDO indicates support for ____.
A) Voice
B) Data
C) A and B
D) None
Answer:B

65) CDMA2000 uses ___ Access technology.
A) Code Division
B) Time Division
C) Both Code Division and Time Division
D) None
Answer:C

66) Which is the 4G version of CDMA2000 technology?
A) LTE
B) UMB
C) EVDV
D) None
Answer:B

67) Which is the error correction code used in CDMA based networks?
A) Turbo Code
B) Convolution Code
C) Both Convolution Code and Turbo Code
D) None
Answer:C

68) Name the type of Spread Spectrum modulation technique?
A) Frequency Hopping SS
B) Direct Sequence SS
C) Time Hopping SS
D) All
Answer:D

69) What are the 4 parts of a CDMA architecture or structure?
A) Mobile Station (MS), Base Station Subsystem (BSS)
B) Mobile Switching Subsystem (MSS)
C) Operation and Maintenance Subsystem (OMM)
D) All
Answer:D

70) What are the systems present in a BSS?
A) One or more BTS (Base Transceiver Station)
B) One or More BSC (Base Station Controller)
C) A and B
D) None
Answer:C

71) What are the systems present in a MSS?
A) MSC (Mobile Switching Center)
B) VLR, HLR
C) EIR, AuC
D) All the above
Answer:D

1. Which type of cell provides the best level of service for average subscribers?
a) Acceptance cell
b) Barred cell
c) Reserved cell
d) Suitable cell
Answer: d
Explanation: A suitable cell is a cell on which the UE may camp on to obtain normal service. The UE shall have a valid USIM and such a cell shall fulfil all the following requirements. It provides the best level of service for average subscribers.

2. With the normal cyclic prefix, how many symbols are contained in 1 frame?
a) 7
b) 140
c) 12
d) 40
Answer: b
Explanation: There are two different type of Cyclic Prefix. One is normal Cyclic Prefix and the other is ‘Extended Cyclic Prefix’ which is longer than the Normal Cyclic Prefix. Normal cyclic prefix contains 140 symbols in 1 frame.

3. What is the PBCH scrambled with?
a) Current frame number
b) Physical cell ID
c) UE’s CRNTI
d) Not scrambled
Answer: b
Explanation: The PBCH is scrambled prior to modulation with a cell-specific sequence that depends on the cells’ identity. In contrast to the synchronization signals, the PBCH is transmitted on the 72 reserved subcarriers, which are QPSK-modulated.

4. What is the length of the shortest possible PDCCH in bits?
a) 144
b) 288
c) 72
d) 576
Answer: c
Explanation: PDCCH is a physical channel that carries downlink control information (DCI). Shortest possible PDCCH is 72 bits.

5. What is the average uploading speed of 4G LTE network?
a) 1-3 Gbps
b) 2-5 Gbps
c) 1-3 Mbps
d) 2-5 Mbps
Answer: d
Explanation: Verizon 4G LTE wireless broadband is 10 times faster than 3G able to handle download speeds between 5 and 12 Mbps (Megabits per second) and upload speeds between 2 and 5 Mbps.

6. Which of the following is not a part of the characteristic of 4G network?
a) Multirate management
b) Fully converged services
c) Software dependency
d) Diverse user devices
Answer: a
Explanation: 4G is the fourth generation of broadband cellular network technology, succeeding 3G. Its characteristics include fully converged services, software dependency and diverse user devices.

7. What does SGSN stands for?
a) Serving GPRS Support Node
b) Supporting GGSN Support Node
c) Supporting GPRS Support Node
d) Supporting Gateway Support Node
Answer: a
Explanation: The Serving GPRS Support Node (SGSN) is a main component of the GPRS network, which handles all packet switched data within the network, e.g. the mobility management and authentication of the users. The SGSN performs the same functions as the MSC for voice traffic.

8. What location management feature is supported by 4G?
a) Concatenated Location Registration
b) Concurrent Location Register
c) Concatenated Management
d) Collated Location Registration
Answer: a
Explanation: 4G supports concatenated location registration. Concatenated location registration reports to the network that they are concatenated to a common object.

9. In 2007 ____________ announced its plan to transmit its network to 4G standard LTE with joint efforts of Vodafone group.
a) Verizon Wireless
b) AirTouch
c) Netflix
d) V Cast
Answer: a
Explanation: In 2007, Verizon announced plans to develop and deploy its fourth generation mobile broadband network using LTE, the technology developed within the Third Generation Partnership Project (3GPP) standards organization.

10. Hybrid ARQ is part of the ____________ layer.
a) PDCP
b) RLC
c) MAC
d) PHY
Answer: c
Explanation: Hybrid automatic repeat request (hybrid ARQ or HARQ) is a combination of high-rate forward error-correcting coding and ARQ error-control. It is part of the MAC layer.

11.Which type of cell provides the best level of service for average subscribers?
A.Acceptable cell
B.Barred Cell
C.Reserved Cell
D.Suitable Cell
Answer: D

12.Which UE categories support 64QAM on the uplink?
A.Only category 5
B.Categories 3, 4 and 5
C.None of them
D.All of them
Answer: A

13.What types of handover are supported in LTE?
A.Hard handover only
B.Hard and soft handovers
C.Hard, soft and softer handovers
D.Handover is not supported
Answer: A

14.Why is a Cyclic Prefix required in OFDMA?
A.To ensure the symbol time is an integer number
B.To help overcome multipath and inter-symbol interference
C.To maintain orthogonality
D.To make OFDMA scalable
Answer: B

15.What does the DC subcarrier indicate?
A.The identity of the cell
B.The antenna configuration
C.The center of the OFDM channel
D.The format of the data channel
Answer: C

16.What processing step combines multiple OFDM subcarriers into a single signal for transmission?
A.FFT
B.IFFT
C.RF Combining
D.Channel Mapping
Answer: B

17.What is the minimum amount of RF spectrum needed for an FDD LTE radio channel?
A. 1.4 MHz
B. 2.8 MHz
C. 5 MHz
D. 20 MHz
Answer: B

18.In MIMO, which factor has the greatest influence on data rates?
A.The size of the antenna
B.The height of the antenna
C.The number of transmit antennas
D.The number of receive antennas
Answer: C

19.What organization is responsible for developing LTE standards?
A.UMTS
B.3GPP
C.3GPP2
D.ISO
Answer: B

20.Which channel indicates the number of symbols used by the PDCCH?
A.PHICH
B.PDCCH
C.PBCH
D.PCFICH
Answer: D

21.How often can resources be allocated to a UE?
A.Every symbol
B.Every slot
C.Every subframe
D.Every frame
Answer: C

22.What property of OFDMA systems allows adjacent subcarriers to be used without interference?
A.Orthogonality
B.Orthodoxy
C.Octagonality
D.Originality
Answer: A

23.With the normal Cyclic Prefix, how many symbols are contained in 1 frame?
A.7
B.12
C.20
D.140
Answer: D

24.What is the largest channel bandwidth a UE is required to support in LTE?
A. 20 MHz
B. 10 MHz
C. 5 MHz
D. 1.4 MHz
Answer: A

25.In OFDM, what is the relationship between the subcarrier spacing f and the symbol time t?
A.There is no fixed relation
B.f = t
C.f x t = 2048
D.f = 1/t
Answer: D

26.What is the PBCH scrambled with?
A.The physical cell ID
B.The current frame number
C.The UE’s C-RNTI
D.The PBCH is not scrambled
Answer: A

27.Why is the Cyclic Prefix a copy of the tail end of the symbol?
A.It ensures a continuous time domain signal
B.It maintains an integer number of cycles
C.It reduces the Peak-to-Average Power Ratio (PAPR)
D.It increases the useful symbol time
Answer: A

28.In LTE, what is the benefit of PAPR reduction in the uplink?
A.Improved uplink coverage
B.Lower UE power consumption
C.Reduced equalizer complexity
D.All of the above
Answer: D

29.Approximately what portion of a subframe in a 1.4 MHz channel is available for carrying the PDSCH?
A. 1/2
B. 1/4
C. 3/4
D. 1/6
Answer: A

30.If the UE detects primary synchronization sequence x and secondary synchronization sequence y, what is the physical cell ID?
A.The physical cell ID cannot be determined from the synchronization signals
B.x+y
C.3x+y
D.x+3y
Answer: D

31.Which RLC mode adds the least amount of delay to user traffic?
A.Acknowledged Mode (AM)
B.Unacknowledged Mode (UM)
C.Transparent Mode (TM)
D.Low Latency Mode (LM)
Answer: C

32.What coding scheme is used for the DL-SCH and UL-SCH?
A. 1/3 tail-biting convolutional code
B. 1/3 turbo code
C. Variable-rate block code
D. 1/3 repetition code
Answer: B

33.How much bandwidth is required to transmit the primary and secondary synchronization signals?
A. 1.4 MHz
B. 1.08 MHz
C. 930 kHz
D. up to 20 MHz
Answer: B

34.What is the length of the shortest possible PDCCH, in bits?
A. 72
B. 144
C. 288
D. 576
Answer: A

35.With PRACH configuration 14, what are the odds that two UE’s will collide during their random accesses?
A. 1 in 10
B. 1 in 64
C. 1 in 640
D. It is impossible to collide on the PRACH
Answer: C

1. MIMO stands for _______
a) Many input many output
b) Multiple input multiple output
c) Major input minor output
d) Minor input minor output
Answer: b
Explanation: MIMO stands for Multiple Input and Multiple Output. It refers to the technology where there are multiple antennas at the base station and multiple antennas at the mobile device.

2. In MIMO, which factor has the greatest influence on data rates?
a) The size of antenna
b) The height of the antenna
c) The number of transmit antennas
d) The area of receive antennas
Answer: c
Explanation: By increasing the number of receiving and transmitting antennas, it is possible to linearly increase the throughput of the channel with every pair of antennas added to the system.

3. MIMO was initially developed in the year __________
a) 1980
b) 1990
c) 1980
d) 1975
Answer: b
Explanation: Since the initial development in the year 1990, MIMO Wireless Communications have become integral part of the most forthcoming commercial and next generation wireless data communication systems.

4. MIMO is a smart antenna technology.
a) True
b) False
Answer: a
Explanation: MIMO is one of several forms of smart antenna technology, the others being MISO (multiple input, single output) and SIMO (single input, multiple output). It is an antenna technology for wireless communications in which multiple antennas are used at both the source and the destination.

5. MIMO technology makes advantage of a natural radio wave phenomenon called _________
a) Reflection
b) Multipath
c) Refraction
d) Diffraction
Answer: b
Explanation: MIMO technology makes use of multipath phenomenon to maximize transmission by receiving bounced signals from obstructions. Multipath is a phenomenon in wave propagation.

6. Which of the following technology does not use MIMO?
a) 4G
b) Wifi
c) WiMax
d) AMPS
Answer: d
Explanation: MIMO is used in mobile radio telephone standards such as recent 3GPP and 3GPP2. In 3GPP, High-Speed Packet Access plus (HSPA+) and Long Term Evolution (LTE) standards take MIMO into account. Moreover, MIMO is also used in Wifi and WiMax.

7. MIMO means both transmitter and receiver have multiple antennas.
a) True
b) False
Answer: a
Explanation: MIMO provides a way of utilising the multiple signal paths that exist between a transmitter and receiver to significantly improve the data throughput available on a given channel with its defined bandwidth. It uses multiple antennas at the transmitter and receiver along with some complex digital signal processing.

8. _______ is a technique of transmit diversity used in UMTSS third-generation cellular systems.
a) STTD
b) SM
c) Collaborative Uplink MIMO
d) MU-MIMO
Answer: a
Explanation: Space Time Transmit Diversity (STTD) is a technique of transmit diversity used in UMTSS third-generation cellular systems. Space Time Transmit Diversity is optional in the UTRANN air interface, but compulsory for user equipment.

9. _______ is a transmission method used in MIMO wireless communications to transmit encoded data signals independently.
a) STTD
b) SM
c) Collaborative Uplink MIMO
d) MU-MIMO
Answer: b
Explanation: Spatial multiplexing is a transmission method used in MIMO wireless communications to transmit encoded data signals independently and separately (so-called streams) from each of the multiple transmit antennas.

10. _______ is an additional open-loop MIMO technique considered by the WiMAX vendors.
a) STTD
b) SM
c) Collaborative Uplink MIMO
d) MU-MIMO
Answer: c
Explanation: Collaborative MIMO is an open-loop MIMO technique considered by the WiMAX vendors to surge the spectral efficiency and capacity of the uplink communications path. It is compared with the regular spatial multiplexing, wherein data streams are transmitted multiplying from multiple antennas on the same device.

11. Smart antenna integrates the contributions of _____ antenna elements.
a) band distributed
b) band centralized
c) spatially distributed
d) spatially centralized
Answer: c
Explanation: Smart antenna integrates the contributions of spatially centralized antenna elements. Frequency reuse and co-channel suppression characteristics of smart antenna provide wireless communication systems with large capacity and high quality links.

12. If a multibeam array has ____, it may not be feasible to assign a complete frequency-reuse plan to each beam.
a) a single beam
b) two beams
c) less than five beams
d) more than ten beams
Answer: d
Explanation: If a multibeam array has more than ten beams, it may not be feasible to assign a complete frequency-reuse plan to each beam. This is due to the interference with adjoining sectorized antennas.

13. Interference with adjoining sectorized antennas can be avoided by _____
a) frequency nulling
b) spatial nulling
c) spatial beam-forming
d) frequency beam-forming
Answer: b
Explanation: The interference with adjoining sectorized antenna can be avoided by the introduction of spatial nulls in the direction of nonsubscriber signal components. In high traffic intensity areas, nulls track subscribers that are on the same frequency and cancel their path movements.

14. Spatial nulling subsystem replaces three element sectors of conventional base station with ____ disposed antenna elements.
a) four spherically
b) eight spherically
c) four circularly
d) eight circularly
Answer: d
Explanation: Spatial nulling subsystem replaces three element sectors of conventional base station with eight circularly disposed antenna elements. The signal is then preamplified and converted to digital form using eight wideband ADCs.

15. In the context of smart antenna, SAT stands for _____
a) Scholastic Assessment Test
b) Site Acceptance Test
c) Saturation
d) Supervisory Audio Tones
Answer: d
Explanation: The out-of-band Supervisory Audio Tones generated by the basestation is relayed in the mobile. The base station can therefore differentiate its subscribers from cochannel interference based on SAT.

16. _____ process determines delay azimuth parameters.
a) Stationary
b) Auto correlation
c) Cross correlation
d) Convolution
Answer: c
Explanation: Cross correlation process determines delay azimuth parameters needed for the final beam forming-equalization stage. The resulting signal exhibits enhanced carrier to interference ratio.

17. Which of the following statements is false regarding the spatial distribution of a wavefront?
a) Multipath components are collinear with direct path
b) Multipath components have less signal strength than direct path
c) Multipath components are present
d) Multipath components exhibit time delay
Answer: a
Explanation: Multipath components exhibit delay with respect to main components. They are not collinear with direct path. They have less signal strength than direct path. When interference is present, it tends to mix with multipath components.

18. In space-time adaptive processing, _____ and equalization parameters are calculated _____
a) diversity, jointly
b) diversity, independently
c) beamforming, jointly
d) beamforming, independently
Answer: c
Explanation: Space-time adaptive processing involves two-dimensional filtering technique using a phased array antenna with multiple spatial channels. In space-time adaptive processing, beamforming and equalization parameters are calculated jointly.

19. In ____, the interference has difference placement on the long-code.
a) GSM
b) AMPS
c) CDMA
d) FDMA
Answer: c
Explanation: Cellular systems employ different techniques to differentiate subscriber signal from co-channel interference. In the case of CDMA, the interference has a different placement on the long-code. In the case of GSM, the burst has different header bits.

20. ____ is a method used for calculating beamforming weights.
a) Sample matrix inversion
b) Indirect matrix inversion
c) Convolution
d) Correlation
Answer: a
Explanation: Sample matrix inversion or direct matrix inversion is a method used for calculating beamforming weights based on a known training sequence of length L. Adaptive algorithms iterate the weights in accordance to the received training sequence. A final estimate is obtained at the end of the training sequence.

21. ____ technique exploits lack of coherence between desired signal and interference.
a) Multibeam arrays
b) Adaptive spatial nulling
c) Beamforming
d) Space-time adaptive processing
Answer: d
Explanation: Space-time adaptive processing technique exploits lack of coherence between desired signal and interference. It separated the signals in parameter space. It can be employed to reduce collinear interference.

22. In_____, the highest-power signal is demodulated to estimate its bitstream.
a) maximum likelihood
b) sequential interference cancellation
c) least mean square
d) recursive least square
Answer: b
Explanation: In sequential interference cancellation, the highest-power signal is demodulated to estimate its bitstream. By employing this technique, co-channel interference from strongest interferer can be reduced substantially.

23. Decoded Channel Bits Interface is defined between ____ functional block and ____ functional block.
a) antenna, RF/IF
b) RF/IF, modem
c) modem, INFOSEC
d) INFOSEC, bitstream
Answer: c
Explanation: The process of digital to analog conversion, filtering add noise to signals. To mitigate this condition, an interface is introduced between the smart antenna and the core base station. Decoded Channel Bits Interface is defined betweenmodem functional block and INFOSEC functional block.

24. Multibeam antenna technology is more complex than null-forming.
a) True
b) False
Answer: b
Explanation: Null forming is more complex than mutlibeam antenna technology. Multibeam antenna is used to enhance SNR. Null-forming is used to suppress interference in high density traffic.

25. Maximum likelihood techniques formulate the likelihood ratio for a sequence of channel symbols.
a) True
b) False
Answer: a
Explanation: Maximum likelihood techniques formulate the likelihood ratio for a sequence of channel symbols. The maximum likelihood ratio determines signal parameter estimate.

26. Which of the following statements is false regarding smart antenna for 802.11 applications?
a) Coverage area is increased
b) Signal paths are reduced
c) Probability of collisions is increased
d) Interference is reduced
Answer: c
Explanation: Smart antenna allows improved SNR so coverage area is also increased. The signal paths are reduced so the multi-path reduction, the transmitted RF energy is confined to a desired direction so interference is reduced. Probability of collisions is reduced and network capacity is increased.

27. Which of the following is not the advantage of smart antenna?
a) Range is increased
b) Secured transmission
c) Design of trans-receiver is simple
d) Probability of collisions is reduced
Answer: c
Explanation: The design of trans-receiver for a smart antennas is quite complex than a traditional base station trans-receiver. Secured transmission, increase in range, reduction in probability of collisions is benefits of smart antenna.

28. Which of the following is used to distinguish the selected signal and the multipath signal in smart antenna architecture?
a) DSP procedure
b) Switched beam array
c) Range gates
d) Delay Cancellers
Answer: a
Explanation: Adaptive array system change the sign patterns with respective to RF settings. DSP procedure is used to differentiate the selected signal from the multipath signals. Switched beam is used for forming multi rays in specific orders. Range gates and delay line cancellers find applications in MTI radars to get the accurate target information.

29. Which of the following is mostly used to generate multiple fixed beams by augmentation in specific orders?
a) Switched Beam array
b) Range gates
c) Conical Scanning
d) FMCW radar
Answer: a
Explanation: Switched beam is used for forming multi rays in specific orders. Range gates and delay line cancellers find applications in MTI radars to get the accurate target information. In conical scanning continuous scanning is performed by beam.

30. In which of the following type of smart antenna, the performance of the multi-channel fading is limited?
a) Diversity system
b) Omni-directional system
c) Sectored system
d) Directional system
Answer: a
Explanation: In Diversity system, multi-path fading, co-channel interference, delay spread impairments are greatly reduced in smart antennas. Directional system uses sectored antennas reference to provide the energy to intended direction.

31. Which of the following is not the benefit of smart antenna?
a) It increases the SIR
b) It decreases the SIR
c) It increases the SNR
d) Probability of collisions is reduced
Answer: b
Explanation: Probability of collisions is reduced so the inference is also reduced in smart antennas. Thus the Signal to interference (SIR) increases in this. The SNR is also high as the multipath fading is also reduced n diversity type system.

32. In Smart antennas, signal to interference ratio is low.
a) True
b) False
Answer: b
Explanation: Probability of collisions is reduced so the inference is also reduced in smart antennas. Thus the Signal to interference (SIR) increases in this by increasing the signal strength and reducing the interference.

33. Which of the following suffers the co-channel interference most?
a) Smart antennas
b) Sectored antennas
c) Omni-directional
d) Both Smart antenna and Omni-direction
Answer: c
Explanation: Omni-directional suffers more co-channel interference compared to the sectored and smart antennas. Probability of collisions is reduced so the inference is also reduced in smart antennas. Thus, the Signal to interference (SIR) increases.

34. Smart antennas can be used for location-specific service.
a) True
b) False
Answer: a
Explanation: The spatial detection nature of the smart antenna enables to locate humans in emergencies. It is used for location-specific services.

35. Which of the following is benefit of smart antenna?
a) It is easy to tap the connection by the intruder apart from the user
b) Co-Channel interference is less compared to the Omni-directional
c) Design of Trans-receiver is complex
d) It cannot be used for location-specific services
Answer: b
Explanation: The spatial detection nature of the smart antenna enables for location specific services. Probability of collisions is reduced so the inference is also reduced in smart antennas. Thus the Signal to interference (SIR) increases in this. Smart antennas provide security so it is difficult for the intruder to get the user connection.

36. Which of the following is the drawback of smart antenna?
a) Design of trans-receiver
b) Spacing between base stations
c) Probability of collisions being reduced
d) Focused to an intended direction
Answer: a
Explanation: Design of trans-receiver is a complex when compared to the traditional base station trans-receivers because separate trans-receiver chains are needed for each array elements. Probability of collision reduction, focusing on desired direction is the benefits of smart antenna.

37. Which of the following statement regarding smart antenna is false?
a) Design of transceiver is complex
b) Smart antennas is more directive
c) Smart antenna is more expensive
d) Numeric processors and control systems are not needed in smart antennas
Answer: d
Explanation: Compared to the traditional base station trans-receivers, design of trans-receiver is a complex because there is a need of separate trans-receiver chains for each array elements. Smart antennas are more directive and costly. The base stations need very powerful numeric processors and control systems.

38. ____ are used to interact with the environment.
a) Sensors
b) Actuators
c) Structure models
d) Memory
Answer: b
Explanation: A cognitive radio consists of sensors to collect information on the environment, actuators to interact with the environment, and a model of the environment with observed events stored in memory.

39. Cognitive radio requires ____ to lower the impact in case of malfunction.
a) diodes
b) regulators
c) PID controllers
d) bridges
Answer: b
Explanation: Cognitive radio requiresregulators to lower the impact in case of malfunction. The most popular regulator used to constraint a cognitive radio is a regulatory policy engine that has machine-readable and interpretable policies.

40. The ____ property allows elimination of a policy upon producing undesirable results.
a) evaluate
b) examine
c) try out
d) permanent
Answer: c
Explanation: Machine readable policy controlled radio allows a policy to be implemented on few radios to assess the impact of the policy. If the results are undesirable, then policy can simply be eliminated. This enables quick decision making.

41. _________ regulations can be made in policy driven approach.
a) Material variant
b) Size variant
c) Temperature variant
d) Spatially variant
Answer: d
Explanation: Policy driven approach allows temporal and spatially variant regulation. For example, a radio can automatically adapt to varying jurisdictions imposed by different countries by modifying or uploading a policy.

42. Which among the following allows quality of service measurement?
a) Software capable radio
b) Software programmable radio
c) Software defined radio
d) Aware radio
Answer: d
Explanation: An aware radio provides quality of service measurement and channel state information in addition to the services provided by software defined radio. However it cannot modify the radio parameters according to sensor input.

43. Which among the following is a quality not available in a software capable radio?
a) Frequency hopping
b) Networking capability
c) Link establishment
d) Programmable cryptography
Answer: b
Explanation: Frequency hopping, link establishment, and programmable cryptography are the features available in software capable radio. Each higher level radio possesses these basic capabilities with additional qualities. Networking capability and multi-waveform interoperability are additional features exhibited by software programmable radio.

44. Cognitive radio includes ____
a) heterogeneous infrastructure
b) asymmetrical infrastructure
c) equivalence infrastructure
d) symmetrical infrastructure
Answer: a
Explanation: Heterogeneous network have heterogeneous radio framework management. It is possible to allocate frequency bands to different radio access technologies. Thus combination of different technologies can be achieved by heterogeneous network.

45. Bands are allocated to radio access technology ____ in such a way that ____ is ____
a) dynamically, capacity, minimized
b) statically, interference, minimized
c) dynamically, capacity, maximized
d) statically, interference, maximized
Answer: c
Explanation: Bands can be allocated to radio access technology dynamically in such a way the capacity is maximized and interference is minimized. The network operator may employ different radio access technology in accordance to time, frequency, and location. It can be used to acquire or exchange spectrum user rights.

46. Which among the following is not listed under cognitive capability?
a) Knowledge on operational environment
b) Adjustment of operational parameters
c) Knowledge on geographical environment
d) Establishment of policies
Answer: b
Explanation: A cognitive radio has cognition, reconfiguration, and learning capability. The automatic and dynamic adjustment of operation parameters based on obtained knowledge to achieve set objective falls under reconfiguration capability.

47. Adaptive radio can experiment new settings.
a) True
b) False
Answer: b
Explanation: An adaptive radio can monitor itself and modify parameters according to sensor input. However learning from results of operations and experimenting with new data and policies is possible only in a cognitive radio.

48. Cognitive pilot channel is used ____
a) to obtain knowledge
b) for geo-location
c) for database access
d) for spectrum sensing
Answer: a
Explanation: Cognitive pilot channel, geo-location, database access, and spectrum sensing are means to gain knowledge. The automatic and dynamic adjustment of operation parameters is done based on obtained knowledge.

49. Heterogeneous cognitive radio is a ____ centric approach.
a) security
b) RF band
c) network
d) environment
Answer: c
Explanation: Heterogeneous cognitive radio has a network centric approach where one or more operators operate several radio access networks using the same or different radio access technologies. Frequency bands allocated to these radio access networks are fixed.

50. In ____, radio access technologies use the same frequency band.
a) network centric approach
b) spectrum sharing
c) spectrum sensing
d) RF band centric approach
Answer: b
Explanation: Spectrum sharing cognitive radio permits same or different radio access technologies to use same frequency band by using unoccupied sub-bands in an intelligent and coordinated way.

51. Global Positioning System uses ____ to determine geo-location of receiver.
a) time of arrival
b) time difference of arrival
c) time of arrival and angle of arrival
d) time difference of arrival and angle of arrival
Answer: b
Explanation: Global Positioning System is a satellite based radio navigation system. It offers a resolution of 100m and requires unobstructed line of sight from satellites. It uses time difference of arrival to determine geo-location of receiver.

52. GPS receivers include a signal that is ____ filtered when it reaches a radio from a satellite.
a) Gaussian
b) Blackman
c) Kalman
d) Sobel
Answer: c
Explanation: Kalman filter uses observed values and provides accurate estimates of unknown variables using joint probability distribution over the variables for each time frame. GPS receivers include a one pulse per second signal that is Kalman filtered.

53. Kalman filter estimates ____
a) time of arrival
b) time difference of arrival
c) propagation delay
d) location
Answer: c
Explanation: Kalman filter provides high resolution estimation of propagation delay from each satellite irrespective of their position. Kalman filter uses input from ground monitoring stations, space weather information, etc. The GPS receivers can estimate time with approximately 340 nanoseconds of jitter.

54. GPS requires at least ___ satellites in view of the receiver.
a) three
b) two
c) five
d) four
Answer: d
Explanation: GPS receiver monitors several satellites to precisely compute the location and clock deviation. It requires at least four satellites to be present in its field of view. Three position coordinates and clock deviation from satellite time are the unknown entities to be computed.

55. ____ aids in the exploitation of unused channels.
a) Spectrum awareness
b) Self awareness
c) Radio resource awareness
d) Location awareness
Answer: a
Explanation: A radio that is aware of spectrum occupancy can use this information to exploit open channels on a non-interference basis. This is the first step in efficient usage of available spectrum. It is done in such a way that primary user of the spectrum is unaffected.

56. ____ proposes the presence of secondary users for improved spectral efficiency.
a) Cognitive radio
b) Software defined radio
c) Software capable radio
d) Programmable digital radio
Answer: a
Explanation: Cognitive radio technologies support the presence of lower priority secondary users. This involves sensing the environment to find unused available spaces in the licensed spectrum for communication. It aims at effective usage of frequency, time and energy.

57. ____ gives available and unavailable spectrum frequency.
a) Unlicensed user pattern
b) Spectrum use pattern
c) Licensed space pattern
d) Licensed user pattern
Answer: b
Explanation: Spectrum use pattern gives the frequencies which are unavailable and unavailable in the band of interest at a particular time and location. It is also known as radio environment, or electromagnetic environment.

58. The secondary user intentionally senses surrounding environment in ____
a) policy approach
b) database approach
c) active awareness
d) passive awareness
Answer: c
Explanation: In active awareness, the secondary user actively senses surrounding environment and performs transmission based on the obtained information. In passive awareness, the radio environment information is obtained outside the secondary communication system.

59. ____ involve the measurement of distinctive features to label and describe individuals.
a) Electrical signals
b) Biometrics
c) Biostatistics
d) Physical signals
Answer: b
Explanation: Biometrics involves the measurement of distinctive features to label and describe individuals. These features are either physiological or behavioural. Different aspects of human physiology, chemistry, and behaviour can be used for biometric authentication.

60. Which among the following is not a behavioural biometric identifier?
a) Voice recognition
b) Gait
c) Fingerprint
d) Typing rhythm
Answer: c
Explanation: Behavioural biometrics is a subclass of biometrics involving the measurement of unique, distinctive and measurable pattern in individuals. Software is required for analysis. It is cost effective means to improve security.

61. Which among the following is not a characteristic of biometric?
a) Measurability
b) Shape
c) Universality
d) Permanence
Answer: b
Explanation: Universality indicates every individual should possess the trait. Permanence indicates the selected trait must remain invariant for longer period of time. Measurability indicates the means to obtain the biometric.

62. During ____, the biometric of an individual is captured and stored.
a) sampling
b) enrollment
c) admission
d) learning
Answer: b
Explanation: The first time an individual uses a biometric system is called as enrollment. During enrollment, the biometric of an individual is captured and stored. At any time, the biometric information is detected and compared with the information stored at the time of enrollment.

63. The first step in verification mode is to ____ users.
a) perform one to one comparison of
b) perform one to may comparison among
c) run recognition of
d) generate reference model for
Answer: d
Explanation: Verification mode involves three steps. The first step is to generate reference models for users. Then samples are matched with reference model to generate a threshold for recognition. The third step involves testing.

64. Triangulation may be used for geo-location.
a) True
b) False
Answer: a
Explanation: Triangulation is the process of determining the location of an unknown point by forming triangles to it from known points. In the absence of GPS, triangulation may be used for geo-location based on cooperative and non-cooperative sensing.

65. Spectrum awareness prevents hidden node problem.
a) True
b) False
Answer: b
Explanation: Spectrum awareness is affected by hidden node problem. A receiver might experience interference but may be incapable of informing the cognitive radio. A cooperative approach may be used to mitigate the problem but it is not a complete solution.