1. Define a cell.

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In mobile communication, the coverage area is divided into smaller areas which are each served by it’s own base station. These smaller areas are called cells.

2. What is frequency reuse?

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Spatially reusing the available spectrum so that the same spectrum can support multiple users separated by a distance is known as frequency reuse.

3.What is adjacent channel interference?

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Interference resulting from signals which are adjacent in frequency to the desired signal is called adjacent channel interference.

4.What is a gyroscope?

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• A cluster(N) is a group of cells in which each frequency channel is unique.
• In other words, the N cells which collectively use the complete set of available frequencies is called a cluster.

5.Describe Handoff in brief.

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• Handoff is the process of transferring a call from one base station to another when a user's radio signal becomes weaker at the first and stronger at the second base station.
• "Weaker" and "stronger" is quantified by a signal threshold level, which is above the minimum signal level for acceptable voice communications.
• Selecting this threshold level is critical to
1) ensure unnecessary handoffs do not occur;
2) call dropping does not occur.

6.What is co-channel interference?

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Interference between signals from co channels are termed as co channel interference

7. Define Trunking theory

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Trunking theory states that “To accommodate large no. of users in a limited radio spectrum.”

8. What is Cell splitting ?

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• Cell splitting involves subdividing a congested cell into smaller cells.,each with its own base station and thus reduction in antenna and transmitter power.
• Here , more the number of cells , more is the clusters and thus higher is the capacity.

9. State advantages of cell sectoring. State the advantage of umbrella cell approach.

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• Sectoring improves capacity by using sectorized antennas (120 degrees, 60 degrees) that reduce the co-channel interference.
• Reduction in co-channel interference means that the cluster size can be reduced which in turn leads to more channels per cell.
• The advantage of umbrella cell approach is that it provides large area coverage to high speed users while providing small area coverage to users traveling at low speeds.