Relay-aided failover in wireless networks using adaptive power and rate unicast scheduling

We present an adaptive power and rate TDMA scheduling algorithm for unicasting messages from base stations to their associated mobile clients in a cellular wireless network. To enhance network robustness, we consider a relay-aided system under which relay stations are placed in fixed locations in each cell area. Upon a base station failure, a relay station is capable of receiving unicast transmissions issued by a neighboring base station, or by a relay station placed in a neighboring cell. Our adaptive power and rate scheduling algorithm reacts to base station failures by reconfiguring the unicast schedule and packet distribution routes. The objective of this paper is to study the performance behavior attained for such a scheme under pre-failure and post-failure scenarios. We show that our failover scheduling algorithm is effective in adapting to base station failures, limiting the performance degradation incurred.