Power-aware MAC for multihop wireless networks: A cross layer approach

This paper addresses the problem of designing a power-aware Multiple Access Control (MAC) protocol for Multihop Wireless Networks (MHWN) using slotted Aloha Code Division Multiple Access (CDMA) at the physical layer. The problem is formulated as one of a cross layer network utility maximization that considers the interaction of transport, MAC, and physical layers in the protocol stack. Assuming physical model for successful transmission, a tractable formula for link throughput as a function of link attempt rate and power vectors is derived. Considering the effect of self-interference in analysis, an algorithm for adjusting the sessions rate and links state, i.e., links attempt rate and power, is derived. Sessions rate and links state are coordinated by congestion signals feedback to sources and messages broadcasted by links respectively. Analysis and simulation results show that adjusting the link state can mitigate the interference and improve the utilization of network resources. Also, it is shown that for a given link at the equilibrium, the link state should be adjusted on the basis of the link location in the network. This result emphasizes that in MHWN, MAC should be designed by considering both time and space contentions between links, which in turn, are provided by adjusting the links attempt rate and power.