1. PREPARED BY: MUHAMMAD TALHA ISLAM SECTION C 2010-TE-054 TELECOMMUNICATION ENGINEERING DEPARTMENT

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4. Sectoring cell splitting keeps D / R unchanged (same cluster size and CCI) but increases frequency reuse/area alternate way to ↑ capacity is to _____ CCI (increase S / I ratio) 4

5. replace omni-directional antennas at base station with several directional antennas 3 sectors → 3 120° antennas 6 sectors → 6 60° antennas 5

6. cell channels broken down into sectored groups CCI reduced because only some of neighboring co- channel cells radiate energy in direction of main cell center cell labeled "5" has all co-channel cells illustrated only 2 co-channel cells will interfere if all are using 120° sectoring only 1 co-channel cell would interfere when using 60° sectoring If the S/I was 17 dB for N = 7 and n = 4, what is the S / I now with 120° sectoring? 24.2 dB 6

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8. How is capacity increased? sectoring only improves S/I which increases voice quality, beyond what is really necessary by reducing CCI, the cell system designer can choose smaller cluster size (N ↓ ) for acceptable voice quality smaller N → greater frequency reuse → larger system capacity What would the system capacity, C new, now be when 120° using sectoring, as compared to the old capacity, C old ? 8

9. Example 9

10. SOLUTION 10

11. PROS AND CONS much less costly than cell splitting only require more antennas @ base station vs. multiple new base stations for cell splitting primary disadvantage is that the available channels in a cell are subdivided into sectored groups trunked channel pool ↓, therefore trunking efficiency ↓ There are more channels per cell, because of smaller cluster sizes, but those channels are broken into sectors. 11

12. other disadvantages: must design network coverage with sectoring decided in advance can’t effectively use sectoring to increase capacity after setting cluster size N can’t be used to gradually expand capacity as traffic ↑ like cell splitting More Handoffs More antenna, more cost 12

13. JAZAKALLAH