Compare the omni cells and sectorized cells.

Comparison of Omni cells (Non sectorized Cells) and Sectorized Cells:

Omni cells:

If a K = 7 frequency-reuse pattern is used, the frequency sets assigned in each cell can be followed by the frequency-management chart. However, terrain is seldom flat; therefore, K = 12 is sometimes needed for reducing cochannel interference. For K = 12, the channel-reuse distance is D = 6R, or the cochannel reduction factor q = 6.

Sectorized Cells: There are three basic types.

1. The 120◦-sector cell is used for both transmitting and receiving sectorization. Each sector has an assigned a number of frequencies. Changing sectors during a call requires handoffs.

2. The 60◦-sector cell is used for both transmitting and receiving sectorization. Changing sectors during a call requires handoffs. More handoffs are expected for a 60◦ sector than a 120◦ sector in areas close to cell sites (close-in areas).

3. The 120◦ or 60◦-sector cell is used for receiving sectorization only. In this case, the transmitting antenna is omni directional. The number of channels in this cell is not sub- divided for each sector. Therefore, no handoffs are required when changing sectors. This receivingsectorization-only configuration does not decrease interference or increase the D/R ratio; it only allows for a more accurate decision regarding handing off the calls to neighboring cells.