Enhancing the Performance of Wireless Ad Hoc Networks Using Spreading Codes

Power conservation for maximizing the lifetime of the limited battery powered ad hoc networks are one of the most important factors in a network design. Transmitting at high power may assure network connectivity but sacrifice network lifetime and increases the interference as well. Meanwhile transmitting at lower power reduces the interference on the expense on network robustness. We investigate the minimum transmit power to optimize those goals taking into consideration the effect of several network design parameters such as the data rate, node spatial density and traffic load. This was done considering a cross layer design optimization between the parameters of physical (PHY) and Medium Access Control (MAC) layers to show how they are related considering the route QoS in terms of a given threshold for the probability of error at the end of a multi-hop route. We motivate the use of spreading codes in the physical layer in wireless ad hoc networks. We show that the use of spreading codes together with spatial reuse can achieve a flexible achievement tradeoff among different parameter metrics.