Optimal Bit Loading Algorithm for Power-Line Communication Systems subject to Individual Channel Power Constraints

Multichannel modulation technique has been successfully applied to power-line communication networks because of its elegant water-filling algorithm for optimal bit-loading. This algorithm maximizes the total channel capacity of the communication system by appropriately matching the signal power to the channel noise level. This paper extends such an algorithm to the case where transmission power at different channels are constrained individually. Such constraints arise naturally in power-line communication systems. An algorithm is carefully developed for such a unfriendly communication environment. This algorithm is an iterative water-filling algorithm in nature, so that the simple and intuitive feature of the well- known water-filling algorithm can be preserved. The individual channel constraints are met using an iterative procedure, which guarantees the optimal solution can be reached within finite iterations. An illustrative system is simulated to demonstrate the efficiency of the proposed algorithm. Furthermore, the proposed algorithm is also well justified using theoretical results.