Joint power and bandwidth allocation for discrete-rate multi-user link adaptation with imperfect channel state information

In practical wireless networks, the available transmission power and bandwidth are limited resources. Therefore, joint bandwidth and power allocation for wireless multi-user networks is essential in order to improve the network performance. Most of the research has focused on continuous rate, power, and bandwidth allocations in the presence of perfect channel knowledge. However, this is not the case with practical systems. In this paper, we therefore consider the issue of discrete power and bandwidth allocation for discrete-rate multi-user link adaptation with imperfect channel state information. To be more specific, we discuss how the system can be designed in such a scenario for i) sum rate maximization and ii) average power minimization in a multi-user setting. The results show that with only a few codes, we can approach the performance of systems that employ continuous (infinite) rates. We have also found that imperfect channel information at the base station affects the performance such that the sum rate is decreased and the average power consumption is increased.