The availability of spectrum resources has not kept pace with wireless network popularity. As a result, data transfer performance is often limited by the number of devices interfering on the same frequency channel within an area. In this paper, we introduce a protocol that manages the transmission power and CCA threshold of 802.11 devices to maximize network performance. The protocol is based on the observation that for a pair of interfering wireless links, it is possible to calculate the ratio of the transmit power of the two senders that maximizes overall network capacity.
We first present an algorithm that extends this result for dense clusters of nodes and then describe a distributed protocol that implements the transmission power setting algorithm and CCA tuning mechanism.
Finally, we describe an implementation of the project in Linux. It uses commercial 802.11 cards and addressed several practical challenges such as protocol stability and calibration. Our experimental evaluation using an 8 node testbed shows that our protocol works well in practice and can improve the performance over default configurations by more than 200%. We also use OPNET simulations to evaluate larger topologies with different node densities.