Kasami Code-Shift-Keying Modulation for Ultra Wideband Communication Systems

Ultra wideband (UWB) communication systems are generally applied to short-range wireless communications. In order to achieve higher rates or to support multiple access capabilities, direct sequence spread spectrum (DSSS) techniques have been introduced to UWB systems. Furthermore, the concept of M-ary code shift keying (M-CSK) was introduced into DSSS systems to achieve higher rates. In this work, we propose an M-CSK modulation technique based on the large set of Kasami sequences since it possesses good code properties. The modulation and demodulation schemes are developed and the system performance is well investigated. It is found that the Kasami M-CSK modulation outperforms other M-CSK modulation techniques or some UWB systems. Furthermore, based on our demodulation scheme, the hardware complexity of receivers can be greatly reduced to O(M^1/3) and the implementation for a large M becomes feasible