Research On Low Complexity Non-coherent Unitary Space Time Modulation

Space time coding,an effective technology in MIMO （Multi-inputMulti-output）,includes coherent space time code and noncoherent space time code. Whenthe channel state information(CSI) is unknown, it is called coherent space time code,otherwise, it is called noncoherent space time code. This paper studies the modulation anddemodulation systems made up of noncoherent unitary space time code and proposed alow complexity unitary space time code—SC-USTM. Construct coding-modulationsystem and its corresponding dual demodulator after combining LDPC code withSC-USTM. Finally, design the noncoherent space time code based on training symbolswith information.First, non-coherent unitary space time matrix SC-USTM based on trigonometricfunction is proposed as well as its angel demodulator. According to the design criterion thepaper designs the structural unitary space time constellation called SC-USTM. Then basedon the ML algorithm the corresponding angel demodulator is deduced, whose complexityhas nothing with L and linear with MN.Second, the system combining channel coding–LDPC code in the IEEE802.16e andunitary space time modulation—SC-USTM is studied. The MAP algorithm suitable forSC-USTM is deduced. Then the paper proposes a novel dual demodulator based on theangel demodulator. Finally, the iterative feedback system and its advanced method isproposed. The LDPC coded SC-USTM modulated system can reach the balance betweenperformance and complexity.Finally, this paper proposes the practical non-coherent space-time codes system basedon training symbols. The SC-USTM rather than the identity matrix is transmitted as thetraining symbol while the Golden code and Alamouti space time codes with the bestperformance at present as the data symbols, both of which carry data information. Themodel has a high rate,good performance and low complexity.