Optimizing Throughput of UWB Networks with AMC, DRP, and Dly-ACK

In wireless networks, the physical layer adaptive modulation and coding (AMC) scheme has been proposed to improve bandwidth efficiency over the time-varying channel. In this paper, we study the performance of ultra-wideband (UWB) based wireless personal area network where AMC is coupled with the distributed reservation protocol (DRP) and the delayed- acknowledgement (Dly-ACK) schemes at the link layer. Considering the channel variation caused by the people shadowing effect, we first propose an analytical model using an embedded Markov chain to investigate the queuing behavior at sender's buffer. Second, the throughput optimization problem is formulated and the optimal transmission mode and payload length are obtained. Simulation results are given to validate the analysis. By jointly considering channel characteristics, physical layer and link layer transmission schemes, the analytical results of the paper can provide useful guidelines for cross-layer optimization, which is essential to ensure quality of services in UWB networks.