Rate and power control in a two-user multicarrier channel with no coordination: the optimal scheme versus a suboptimal method

Maximizing the total rate with no coordination is an attractive option to increase the throughput of existing multiuser communication systems. The paper compares a suboptimal method for rate and power allocation in a two-user multicarrier channel with the optimal method, subject to individual power constraints. The suboptimal method, iterative waterfilling (IW), closely approximates the performance of the optimal method when interference power is small. Moreover, IW is easy to deploy in existing systems in which different transmission paths may not be coordinated.