An Efficient Fixed Rate Transmission Scheme Over Delay-Constrained Wireless Fading Channels

Abstract

Abstract-In this paper, we study the scheduler design over delay-constrained wireless communication links. Following a cross-layer design approach, the wireless system is modeled as a joint link-PHY layer architecture with a finite-length buffer and continuous-state fading links. A heuristic and efficient fixed rate transmission scheduler (FRT) scheme is proposed. We formulate and analyze the performance of the FRT scheme in terms of power efficiency and packet drop rate. Compared with variable rate schemes, the FRT scheme can considerably simplify the hardware implementation of the transmitter. In addition, the optimization of the FRT scheme can be conducted with significantly reduced computational cost by utilizing the sparse feature of the transition probability matrix. Moreover, the simulation results show that, the optimized average transmit power of the FRT scheme is only 0.5 dB higher than the known optimal variable rate scheme at the packet drop rate of 10 −3 , indicating that the FRT scheme is quite power efficient as well. Therefore, we conclude that the FRT scheme is more feasible than variable rate schemes in practical delay-constrained wireless systems with regard to both hardware cost and power efficiency.