Cross-Layer Optimization for Wireless Mesh Networks with Multi-Antenna Beam-Forming

In this work a cross-layer optimization in centralized Wireless Mesh Networks equipped with multiple antennas is introduced. A scenario has been considered in which multiple antennas at each node are employed to suppress the interference through beam-forming. By integrating different constraints from MAC and Network layers, a mathematical LP formulation is presented to minimize the system activation time. Since the optimization problem is a complex combinatorial one, the optimal solution is approached by a Column Generation decomposition method. Numerical results indicating the theoretical capacity limit of the network are provided for different node densities, transmission ranges and number of antennas. It is shown that interference suppression increases the spectrum spatial reuse and enhances the throughput of the network by minimizing the operation time duration of the system. Moreover, depending on the density of the interference and traffic sessions, there is a saturation threshold on the number of antenna elements; beyond that, more antennas do not necessarily result in smaller system activation time. Furthermore, increasing the transmission range leads to decrease the system activation time of such networks.