Transmit Power Control in Wireless Mesh Networks Considered Harmful

A wireless mesh network (WMN) serves to extend the coverage of access points (APs) by means of relay nodes (RNs) that forward data between mobile nodes (MNs) and an AP. This concept reduces deployment costs by exchanging the wires between APs by a wireless backbone. Unfortunately, this also reduces capacity, owing to multiple transmissions of the same data packet on its multi-hop route. Hence, different mechanisms to increase the capacity of WMNs are investigated, one of them being transmit power control. By limiting the transmission power, interference on other links is reduced. As a consequence, it should be possible for them to use more susceptible and thus higher- rate modulation- and coding schemes (MCSs), which improves the system capacity. Unfortunately, the reduction of the transmission power has also the effect that the received signal power is reduced, which then requires more robust (lower-rate) MCSs, reducing capacity. In this paper, we use an analytical framework to compute the upper capacity bound of wireless mesh networks (WMNs) with and without transmit power control. The comparison shows that the negative influence of the power control dominates the positive.