Discuss the three different mechanisms to improve the cell capacity and coverage area in a cellular system.
When a cells capacity is no longer able to provide an acceptable QOS, several methods can be to increase system capacity.in areas where there is poor reception of radio signals, the use of repeaters can improve radio coverage
Methods to improve cell capacity and coverage area:
Cell Splitting: The Cell Splitting is the process where a large cell that can no longer provide acceptable service is divided it into smaller cells which are called microcells. These smaller cells are laid out to use the frequency reuse pattern already in the system. As the cells are smaller in size, system capacity increases and less power is used by mobiles and base stations. But because of cell splitting hand-offs become more common. As Many new base stations are needed, so also increases the system complexity and load of MSC.
Sectoring: It is the process of dividing the cells into sectors by using directional antennas. Common sectoring methods divide cells into 3 or six sectors. The S/I ratio increases because interference is received from only 1 direction rather than all directions. This makes it possible for cluster size to be reduced, allowing more channels to be allocated to each cell. But it does not work well in high density urban areas due to reflections. The complexity of the base stations also increases.
Microcell Zones: These are the zones that consists of a single base station with a distributed antenna system. Only one base station needed. Because the system is distributed, less power is needed per antenna, and cells can be closer together without increasing SIR. The cluster size can be reduced, making it possible to allocate more channels to each cell. Handoff between microcells within the cell is handled by the base station, reducing the load on the MSC. Base stations are more complex as they must coordinate multiple antennas.
Briefly describe the congestion control, slow start and fast retransmit mechanism.
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Write short notes on the following:
What is Resource management?
Briefly differentiate between CDMA and GSM technologies.
Write a C program to find a no. is PALINDROME or NOT.
