cell splitting and sectoring
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This power point presentation discusses cell splitting and sectoring techniques used to increase channel capacity in cellular networks. It explains that a large cellular area is divided into smaller hexagonal cells, each with its own base station and frequency set. To further increase capacity, cells can be split into smaller cells served by additional base stations. Alternatively, directional antennas can be used to sector each cell into three segments to reduce interference and allow frequency reuse over smaller areas. Both techniques aim to add channels by subdividing congested cells.
cell splitting and sectoring
- 1. Power point presentation on cell splitting and sectoring MADE BY: : SHWETANSHU GUPTA MIET (342/08)
- 2. CELL? LARGER AREA DIVIDED INTO SMALL NO. OF AREAS SHAPE IS HEXAGONAL EACH WITH ITS OWN BASE STATION AND SET OF FREQUENCIES.
- 3. Why hexagonal cell ? square circular hexagonal
- 4. FREQUENCY REUSE 6 5 Each cell is assigned a part of the available frequency spectrum. 7 1 4 3 6 5 4 2 6 5 1 7 1 4 3 2 3 same part of the frequency spectrum more than once. This is called frequency reuse.
- 5. Reuse Distance For hexagonal cells reuse distance--D= R.√3N Reuse factor--D/R= √3N
- 6. Channel capacity? C = MKN = MS C= capacity M= number of clusters K= allotted channel to a cell N= no of cells in a cluster.
- 7. Why cell splitting and sectoring? As users increases channel capacity decreases. Techniques are needed to provide extra channels. cell splitting and sectoring increases capacity.
- 8. Cell splitting The process of subdividing a congested cell into smaller cell. Each with its own base station and a corresponding reduction in antenna height. leads to increase in capacity
- 9. Limitations: Handoffs are more frequent. Channel assignments become difficult. All cells are not split simultaneously so special care have to be taken for proper allocation of problem.
- 10. Umbrella approach: Handoff issues must be addressed so that high speed and low speed traffic can be accommodated simultaneously.
- 11. Cell sectoring: To overcome some limitations like cochannel interference, cell sectoring is done. Involves replacing an omni- directional antenna at the base station by several directional antennas,
- 13. Advantages: It improves S/I ratio. It reduces interference which increases capacity. It enables to reduce the cluster size and provides an additional freedom in assigning channels.
- 15. Limitations: Increased number of antennas at each base station. Decrease in trunk efficiency. Loss of traffic. Since sectoring reduces the coverage area of a particular group of channels, the number of handoffs increases as well.