RP operating frequencies are assigned automatically and autonomously, eliminating the need for manual frequency planning. The automatic frequency assignment is called quasi- static autonomous frequency assignment (QSAFA). QSAFA is a self-regulating means of selecting individual RP frequency channel pairs that function without a centralized frequency coordination between different RPs. The QSAFA process is controlled by the RPCU for its associated RP transceivers. To start the procedure, the RPCU sends a message to a transceiver to turn off its transmitter. The transceiver is instructed to tune to the downlink frequency band and scan all possible downlink frequencies. Then the transceiver reports the signal power of the frequencies back to the RPCU and amplitude modulation (AM). The frequency with the lowest received signal power at the RP is selected. Finally, the RP transmitter turns to the selected frequency and turns on.

The frequency assignment procedure is repeated by all ports one at a time until no ports request a change in their assigned frequencies for two consecutive cycles. The procedure can be repeatetd until the algorithm converges or until a threshold number of iterations is reached. Because the downlink transmitter must be turned off briefly during the measurement, the measurement should be conducted during low-traffic hours. Simulation study indicated that for 256 ports using 16 frequency pairs, the assignments can always be stabilized within fewer than five iterations. QSAFA combines the principle advantage of dynamic channel allocation in that pre-engineering of a frequency plan is unnecessary with the performance advantages of a fixed frequency assignment; that is, elimination of blind time slots for channel assignment, elimination of call blocking due to resource blocking, and faster call setup and handoff times.

Dynamic channel allocation for TDMA systems is subject to blocking from two sources: interference blocking, whereby the desired channel is blocked due to interference; and resource blocking, whereby the desired channel is blocked because the same time slot (not the same channel) is already in use at the target RP. This resource blocking probability seems to be higher than Erlang-B blocking because of the blind time slot problem. There are two aspects to this problem. The obvious one is that SUs in handoff cannot see the time slot channels they are using or adjacent time slots. The second problem is that SUs attempting initial access or handoff may know the target or best RP, but they do not know the traffic pattern on that RP (i.e., which time slots may be in use on other frequencies). As a result these SUs attempt access to ports on time slots already in use, albeit on a different frequency, and the RP cannot hear them. This problem can be solved by the transmission of blind slot information from each RP on the control channel, at the cost of reducing alerting or system information capability.