A pilot based dynamic channel assignment scheme for wireless access TDMA/FDMA systems

Abstract

The authors propose control architecture for implementing a dynamic channel assignment (DCA) algorithm which optimizes two-way channel quality in a TDMA portable radio system. A common control frequency, which is frame-synchronized among base stations, provides (1) beacons for portables to locate base-stations and obtain DCA information, (2) broadcast channels for system and alerting information, and (3) pilot signals to permit portables to evaluate downlink interference. This allows low-complexity radio ports and portables to simultaneously select channels to avoid interference and avoid creating excessive interference. Only local measurements are needed for this autonomous DCA scheme, thus avoiding processing by a centralized controller or communications among distributed controllers. A superframe structure on the control frequency provides redundant information for the beacon and pilot signals to avoid the blind-slot problems which cause significant difficulty in other systems for the link transfer (hand off) process. Results from computer simulations demonstrate the good spectrum efficiency of this method. They also show that power control further improves the performance significantly. This work is targeted towards understanding the implications to local exchange networks of wireless system alternatives that could provide access to those networks.