Space-time precoded CDMA-OFDMA employing super-orthogonal complete complementary codes

Abstract

This paper addresses and illustrates, both analytically as well as by means of simulation, the equivalence of a cyclically rotated complete complementary coded (CRCCC) code division multiple access orthogonal frequency division multiplexed (CDMA-OFDM) BPSK/QPSK system and a narrowband uncoded BPSK/QPSK reference system. The equivalence can be attributed to the MUI-free characteristic performance of CRCCCs. It is demonstrated that when employed in a multiple-input multiple-output (MIMO) antenna configuration along with orthogonal space-time block codes (OSTBCs), the maximum theoretical diversity order of NTxNRx is achieved. Most significantly, simulations show that CDMA-OFDM using CRCCCs is capable of rendering additional multipath diversity gain at no additional processing cost. This signifies improved performance when compared with conventional ST-OFDM systems.