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.
In recent years the research effort devoted to multi-hop communications (or relaying) and multi-antenna transmissions has been constantly growing due to the potential increase in the spectral efficiency that these technologies could provide. In particular, these play a key role for the air interface being designed within the European IST-4-027756 Project WINNER II due to the tight efficiency requirements it poses. In this paper a strategy is proposed for the dynamic resource partitioning in relay enhanced cells (REC). It allows the exploitation of spatial resource sharing through a simple approach based on a logic beam concept. Two different resource partitioning algorithms are proposed and assessed, one aiming at maximize the cell throughput while the other also ensuring fairness between the users. A quite significant performance gain is shown with respect to conventional solutions based on fixed sectorization.
Berzelius failed to make use of Faraday's electrochemical laws in his laborious determination of equivalent weights.