Performance of UWB Receiver with Cognitive Channel Allocation and Rake Optimization

The design of a UWB receiver for increasing data rate applications has created challenging interest in the research community. Code Division Multiple Access (CDMA) is used as a multiple access technique in our UWB receiver architecture based on the assignment of different spreading codes to a singe user. Since UWB signals are multipath rich, we have used Orthogonal frequency division multiplexing (OFDM)-UWB. OFDM provides better multipath resolution than the single carrier UWB. The addition of iterative Turbo decoding further improves the performance of the receiver in such scenario. Our research work is focused on the performance evaluation of UWB receivers. Thus, rake filtering is also included for optimal multipath diversity which improves the overall performance. Cognitive Radio (CR) plays a vital role in our cross-layer UWB receiver architecture where it exchanges information with the physical layer for probable channel conditions before allocating links dynamically for its data transmission. The receiver performance is evaluated in terms of bit error rate (BER) in severe multipath faded channels with exponential power delay profile. The joint optimization of a strategic selection of propagation paths for the Rake receiver is analyzed using mixed integer programming and simulated using the GLPK tool.