Optimal control of transmission power management in wireless backbone mesh networks

Abstract

This chapter proposes a scalable singularly perturbed weakly-coupled TPM which is supported at the LL of the network protocol stack. Firstly, the WMN is divided into sets of unified channel graphs (UCGs). A UCG consists of multiple radios, interconnected to each other via a common wireless medium. A unique frequency channel is then assigned to each UCG. A multi-radio multi-channel (MRMC) node possesses network interface cards (NICs), each tuned to a single UCG during the network operation. Secondly, the TPM problems are modelled as a singular-perturbation of both energy and packet evolutions at the queue system as well as a weak-coupling problem, owing to the interference across adjacent multiple channels. Based on these models, an optimal control problem is formulated for each wireless connection. Thirdly, differential Nash strategies are invoked to solve such a formulation. The optimization operation is implemented by means of an energy-efficient power selection MRMC unification protocol (PMMUP) maintained at the LL. The LL handles packet synchronization, flow control and adaptive channel coding (Iqbal & Khayam, 2009). In addition to these roles, the LL protocol effectively preserves the modularity of cross-layers and provides desirable WMN scalability (Iqbal & Khayam, 2009). Scalable solutions managed by the LL ensure that the network capacity does not degrade with an increase in the number of hops or nodes between the traffic source and destination. This is because the LL is strategically located just right on top of the medium access control (MAC) and just below the network layer. Message interactions across layers do not incur excessive overheads. As a result, dynamic transmission power executions per packet basis are expected to yield optimal power signals. Furthermore, if each node is configured with multiple MACs and radios, then the LL may function as a virtual MAC that hides the complexity of multiple lower layers from unified upper layers (Adya et al., 2004). Finally, analytical results indicate that the optimal TPM resolves WMN capacity problems. Several simulation results demonstrate the efficacy of the proposed solution compared to those of recently studied techniques (Olwal et al., 2010b). The work in (Olwal et al., 2010b), furnishes an extensive review of the TPM schemes. In this chapter, however, only key contributions related to the MRMC LL schemes are outlined.