Low-complexity rake reception and equalization for MBOK DS-UWB systems

This paper describes low-complexity rake reception and Viterbi equalization techniques for M-ary bi-orthogonal keying direct sequence UWB (MBOK DS-UWB) systems, which have been considered a type of PHY suitable for high-speed WPANs in IEEE802.15.3a. In MBOK DS-UWB systems, rake reception and equalization are essential to compensate interpulse interference generated by multipath fading. For rake reception, we derive a novel technique to reduce its implementation complexity by setting a limit on the number of delay devices. For Viterbi equalization, we provide a reduced-state sequence estimation algorithm that reduces the computation complexity for MBOK DS-UWB systems. By employing the proposed rake reception and Viterbi equalization techniques, the complexity can be reduced to less than half of ordinary rake and equalization techniques. Simulation results show that our rake reception and Viterbi equalization techniques enable almost the same performance as existing techniques despite the lower complexity.