A Solution to Improve Throughput in Wireless Mesh Networks by Using Superposition Coding

Multihop communication popularly exists in current ad-hoc networks, sensor networks, and also the emerging wireless mesh networks which are expected to provide integration of various current wireless networks, such as cellular networks, WiFi, WiMAX, sensor networks. However, low capacity efficiency is a crucial problem in these multihop wireless networks. Two factors pose adverse effects on the capacity of the multihop wireless links: the time-varying and error-prone wireless channels and the low-efficient medium access control (MAC) protocol based on the IEEE 802.11. Recent investigations have shown that in a 802.11 based multihop wireless network with N nodes, the throughput per node is inversely proportional to the square root of N. This factor is really an obstacle for providing high data rate services over multihop wireless networks.In this project, the researchers will make use of cooperative transmission provided by superposition coding to improve the throughput of multihop wireless networks. The researchers will develop an efficient MAC protocol to improve the throughput in the multihop wireless links. The proposed MAC protocol will take advantage of the superposition coding, which is deployed in the physical layer and supports simultaneous transmission of multiple packets, to improve the efficiency over multihop wireless links. In addition, they will introduce cross-layer combining of superposition coding with a truncated ARQ in the link layer to improve the reliability of the multihop wireless links.