Power controlled random access

The lack of an established infrastructure, and the vagaries of the wireless channel make the design of ad-hoc networks a challenging task. Cross-layer design for ad hoc networks has been widely advocated, because it helps overcome several suboptimalities which are introduced by designing each layer in isolation. A cross-layer design encompassing all layers of the protocol stack is hard to achieve, and hence research often looks at pairwise optimizations. One such design methodology for joint link scheduling and power control, which optimizes over the physical and MAC layer is considered here, for a cellular network scenario. By using a heuristic relaxation, the NP-hard problem of joint power control and scheduling is transformed into one of power controlled random access, which can be cast as a convex optimization problem. A physical interpretation is provided for this relaxation. An outage analysis and a Markov chain based end-to-end delay distribution analysis is presented for the proposed scheme, and the efficacy of the scheme is also studied through simulations.