Throughput improvement of 802.11 networks via randomization of transmission power levels

Successive interference cancelation can resolve collisions involving multiple packets and, hence, improve the throughput of an 802.11 network. This technique, however, requires packets to be sent with different power levels. In this paper, we first develop a detailed analytical model to determine the throughput of 802.11 networks with this multiple-packet reception capability. We then study the problem of determining the optimal probability distribution associating with these power levels when the network is operated in infrastructure and ad hoc modes, respectively. In the infrastructure mode, the problem is formulated as an optimization problem with a solution to be broadcast to all the nodes by the access point. In the ad hoc mode, the same problem is formulated as a mixed-strategy game, where individual nodes strategically choose the probability distribution of the transmitting power levels to maximize its own throughput. We show that the Nash equilibrium of this game is Pareto optimal and fair. Furthermore, the resulting throughput of the distributed approach is close to the optimal performance of the infrastructure mode.