| The IEEE 802.16 standard, also known as WiMAX, is an upcoming wireless standard that allows data rates of up to 1 Gb/s. WiMAX can provide last mile connectivity by replacing wired communication channels, without any reduction in data throughput compared to wireline networks. This high data rate requires large bandwidths, which can cause deterioration in the signal due to frequency and time selectivity. In order to overcome these problems, precoding is used in conjunction with OFDM and MIMO in order to overcome the signal deterioration that is caused by the wideband channel. Precoding techniques such as waterfilling allow for optimal power allocation, thereby improving the error performance of a fixed constellation system, at the cost of reduced utilization of available channels. This thesis presents a novel precoding technique that allows an improvement in the utilization of available channels, with minimal effect on the error performance of the system. A realistic channel that is correlated in time, frequency and across the spatial domain is used to evaluate the proposed algorithms. Finally, the effect of feedback reduction and user scheduling on existing and proposed algorithms is studied.;Keyword: Precoding, OFDM, MIMO, WiMAX, feedback reduction, user scheduling. |
