Approximate Optimal Power Allocation Scheme for Wireless Ad hoe Networks in Rayleigh Fading Channels

In this paper, a distributed power allocation scheme for mobile ad hoc networks in Rayleigh fast fading environments is proposed. With fluctuated SINR, outage probability is introduced as a QoS parameter. An optimization model is formulated to minimize total transmit powers with constraint conditions that outage probability of each link should be satisfied. A closedform near optimal solution to the model is presented based on the exploration of power ratio factor at the boundary of system capacity. The solution is implemented in the networks by a distributed power allocation scheme. In terms of the scheme, each link can determine its power ratio factor independently. The inequity problem of the power allocation algorithms in incremental fashion is avoided. Meanwhile the scheme is more timesaving than those schemes in iterative manner. By performance evaluation, we verify our analysis on the optimization model and validate a better result of our scheme in comparison with the counterpart. That is, a larger system capacity is admissible by our method.