Multiple-Stream Code-Multiplexed Transmitted-Reference Ultra-Wideband Systems

In a code-multiplexed transmitted-reference (CM-TR) ultra-wideband (UWB) system [8], the reference pulse trains are made orthogonal to the information-bearing signal by code-shifting. The receiver is simple because it avoids the use of an analog delay line. Moreover, the CM-TR UWB system outperforms the original TR-UWB system in terms of error rates. In this paper, we extend the CM-TR concept to transmit multiple bit streams, forming the multiple-stream code-multiplexed (MSCM) TR scheme. The proposed scheme consists of a code-multiplexed reference signal and several information-bearing signals. Moreover, the data transmission rate of the MSCM-TR scheme is several times that of the CM-TR scheme with the same symbol period. Compared with the CM-TR scheme, the new scheme requires a transceiver with a slightly more complicated baseband processing unit. Theoretical and simulated results show that the error performance of MSCM-TR scheme is comparable with that of the CM-TR scheme when the peak power is not limited. We also analyze the tradeoff between the data rate and the number of frames under a peak-power constraint.