Filter structures for equalization and diversity combining in wireless communications

One of the major problems in the implementation of high bit rate services which incorporate transport of voice, video and data over future indoor wireless communication systems is the severe channel characteristics which give rise to multipath fading and intersymbol interference. These problems can be overcome by using a suitable filter structure that performs equalization and space diversity combining. Filter structures are divided into three classes depending on the sequence in which equalization and diversity combining are performed. In this paper, computer simulations are used to compare the average bit error rate (BER) performance of various filter structures. Various issues such as the effect of channel delay spread, tracking capability at different values of Doppler frequency and filter complexity are considered. New filter structures are proposed that are more suitable than existing ones in terms of computational complexity or/and performance. Substantial improvements in BER performance is shown with virtually no increase in computational complexity