C. Microcell zone concept:

• The increased number of hand off, increase load on the switching and control link because of sectoring. A solution to this problem is given by microcell zone concept
• Large control base station is replaced by several lower power transmitters on the age of cell.
• The mobile retains the same channel and the base station simply switches the channel to a different zone site and the mobile moves from zone to zone.
• Since a given channel is active only in a particular zone in which mobile is travelling, base station radiation is localized and interference is reduced.
• The advantage of zone cell technique is that while the cell maintains a particular coverage radius, co-channel interference in the cellular system is reduced. As the large central base station is replaced by several lower power transmitters on ages of cell. Decreased co-channel interference improves signal quality leads to increase in capacity without degradation in trunking efficiency caused by sectoring.

1. Advantages:

   • Decrease co-channel interference which leads to an improvement in signal quality and also leads to an increase in capacity. No degradation of trunking efficiency.

2. Disadvantages:

   • More antennas are required.

   • Base station need to be more sophisticated to handle transfer of call from one zone to another zone within the cell.