Generalized code-multiplexing transmissions for UWB systems

Traditional transmitted reference (TR) systems for Ultra-Wideband (UWB) communications separate the reference and data-modulated signals in the time domain, thus requiring at the receiver a delay component which is difficult to implement. To circumvent this drawback, frequency-shifted reference (FSR-TR) systems employ an analog carrier to make the reference and data-modulated signals orthogonal with each other. Recently, code-multiplexing TR (CM-TR) and code-shifted reference (CSR) schemes have drawn attention because of their simple hardware structure without delay component or analog carrier, and higher bit error rate (BER) performance over the FSR-TR. In this paper, we illustrate a generalized code-multiplexing (GCM) system based on the formulation of a proper constrained optimization problem, which extends the concept of CM-TR and CSR while retaining their original simple structure. Numerical simulations performed over demanding wireless environments validate the effectiveness of the proposed approach.