OCDM: a new multicode CDM radio transmission system based on cyclic modified M-sequences-performance evaluation using prototype

This paper presents the system configuration and the transmission performance of a new multicode CDM (code division multiplex) based high speed radio transmission prototype which can transmit 4.608 Mbps under AWGN and Rayleigh fading environment. The proposed multicode CDM transmission is based on a already proposed parallel transmission scheme using cyclic modified M-sequence CDM named as OCDM (orthogonal code division multiplex) and consists of a general-purpose RF unit, IF unit and baseband DSP (digital signal processing) unit. All the specified algorithm which realize the proposed transmitter and receiver is only programmed m the baseband unit. Moreover, the programmed algorithm consists of only a feedforward DSP configuration, and adopts a new code synchronization method and RAKE diversity technique. In this paper, moreover, the performance of the proposed system, in terms of the acquisition time and bit error rate (BER) has been evaluated under additive white Gaussian noise (AWGN), non-selective one path Rayleigh and double-spike Rayleigh fading channel by experimental measurement.