Blockage:

There are two types of blockage

1) Set up channel blockage-

• Information regarding Set up channel blockage cannot be obtained for cell site because the mobile unit will be searching for the busy/idle bit of a forward set up channel in order to set up its call.

• If busy bit does not change after 10 call attempts in 1s,a busy tone is generated, and no mobile transmit can take place.

• In another case the mobile transmit take place as soon as the idle bit is shown. The set up channel blockage should be at least less than half of the specified blockage (usually 0.02) in the mobile cellular system.

2) Voice channel blockage -

• Voice channel blockage can be evaluated at the cell site. When all call come in, some are refused for service because there are no available voice channels.

Call drops (Dropped Call rate)-

• Call drops are defined as call drop for any reason after the voice channel has been assigned. Sometimes call drops due to weak signals are called lost calls.

• The drop call rate is partially based on the handoff-traffic model and partially based on signal coverage.