Mitagation against MAI in a Space Time Spreading Software Defined Radio Test Bed

Abstract

A Software Defined Radio test bed using the Gnu Radio project was installed on Unix boxes and modified so that estimates of the channel state coefficients were taken for a Multiple Input Multiple output (MIMO) system to take advantage of space time transmission at a frequency of 2.4GHz. This system was modified to provide a Space Time Spreading test bed. The test bed was modified so that multiple access interference was experienced by offsetting different users data streams. The Walsh-Hadamard and Wysocki (low correlation) spreading sequences were deployed in the test bed to compare their Bit Error Rate performance. We confirmed that the low cross correlation spreading sequences experienced an improved Bit Error Rate compared to that obtained when using the Walsh-Hadamard Spreading sequence for high signal to noise ratios.