Abstract:

The symmetric capacity of slowly fading channels with quantized channel side information (CSI) is investigated. Optimal quantization schemes under different power constraints are derived. Without any power adaptation, the problem becomes a typical one dimension maximum problem. With power control, the optimal power control is pulse like and the optimal solution can be achieved by an iterative fashion. Numerical results show that the 4bits optimal quantization can achieve most of the symmetric capacity with perfect CSI. Besides, different from the Gaussian input results, the symmetric capacity gains of power adaptation are also obvious. For example, with the same quantization level, power adaptation brings about 10% capacity improvements.

Key words: symmetric capacity, channel state information, quantization