The frequency band is used to evaluate the interference of idle time slots. The base station measures the level value of the interference signal on the idle channel to determine the priority of time slot allocation. * * It is divided into five levels (1-5), and the signal level is divided into 63 levels from-1 10dBm to -47dBm. There are four parameters in idle channel measurement, the limit is 65438. LIMIT 1 is the most important parameter. This parameter divides the idle channel into two main parts. One is the idle channel with interference level of 1, which will be put in the first place in channel allocation; Some are idle channels with interference levels of 2 to 5. If there is no free channel in the interference level 1, it is allocated to the free channels with interference level 2 and above.