Research On The Key Wireless Transmission Technologies Based On Interleave Division Multiplexing

Interleave division multiplexing (IDM) relies on interleavers as the only means todistinguish different data streams, and adopts a low-complexity iterative detectionstrategy at the receiver, which has the advantages of high spectral efficiency, beneficialperformance and low detection complexity. Due to the special features, IDM can beused in the multiple access technologies and modulation technologies of future wirelesscommunications. Therefore, this dissertation focuses on some IDM-aided wirelesstransmission technologies in interleave division multiple access (IDMA) andsuperposition coded modulation (SCM) systems.The first chapter of this dissertation introduces the research background and thestatus of the IDM aided multiple access and modulation technologies, and then pointsout the research contents and contributions of this dissertation. Finally, the mainstructure of this dissertation is outlined.In chapter2, the basic transceiver’ structures of IDMA systems are first introduced,and the corresponding iterative detection algorithms in different conditions are derived.Then low density parity check (LDPC) code is adopted in IDMA systems to improvethe attainable system performance. In addition, for reducing its detection complexity, asimplified receiver is proposed, which is capable of achieving a flexible trade-offbetween computational complexity and system performance. In the end, the functionand disadvantages of interleaver in IDMA systems are analyzed, and an interleaverdesign method is proposed based on random sequences, which significantly reduces thecomplexity while maintaining the system performance.According to the results of chapter2, the carrier frequency offset (CFO)compensation and two-dimension signal detection of orthogonal frequency divisionmultiplexing-interleave division multiple access (OFDM-IDMA) systems areresearched in chapter3. Firstly, the basic transceiver’ structures of OFDM-IDMAsystems are introduced. Secondly, CFO compensation problem is investigated and twoCFO compensation algorithms are proposed for OFDM-IDMA uplink. After analyzingthe impact of multiple CFOs in the detection of OFDM-IDMA systems, a new detectionscheme is proposed for CFO compensation. In addition, an improved CFOcompensation algorithm is proposed for reducing the complexity. Because the effects of the residual CFOs from other users are considered, the proposed algorithms caneffectively improve the performance of OFDM-IDMA systems. Finally, OFDM-IDMAsignals are spreaded in the time-and frequency-domain, and then a detection algorithmis proposed for two-dimension signals. The low-complexity interleavers and flexibletransmission rates can be obtained in the two-dimension OFDM-IDMA systems.In chapter4, the CFO estimation, the peak to average power ratio (PAPR)compensation and the channel estimation of SCM systems are researched. Firstly, thebasic transceiver’ structures of SCM-OFDM systems are introduced. After the analysisof the impact of CFO at the SCM-OFDM receiver, two blind CFO estimationalgorithms based on signal detection are proposed, which can significantly improvedspectral efficiency and power efficiency. In the end, the selective mapping (SLM)technology and the Kalman channel estimation algorithm are adopted in SCM-OFDMsystems. Simulation results show that SLM technology can effectively compensatePAPR and keep the system performance, while the Kalman channel estimation cansignificantly improve the estimation performance and obtain BER performance withperfect channel estimation.Signal detection and interference cancellation are investigated for OFDM-IDMAand SCM-OFDM systems in high speed channels in chapter5. Firstly, the impact ofhigh speed channels for OFDM-IDMA and SCM-OFDM systems is analysised. It isfound that the time variation of high speed channels will induce serious inter-carrierinterference (ICI). For OFDM-IDMA systems, three kinds of signal detectionalgorithms are proposed in high speed channels. The conventional algorithm for thequasi-static channels can not be readily used for canceling ICI from high speed channels,which will result in performance degradation. And a novel iterative detection algorithmis developed based on an integrated interference canceller, which can iterativelyestimate and mitigate the ICI as well as multiple access interference (MAI)simultaneously. In addition, an improved detection algorithm is derived for reducing thecomplexity using an approximation of the mean and variance of the interference. ForSCM-OFDM systems, an interference estimation and cancellation algorithm is proposedin high speed channels, which can mitigate the multi-layer interference (MLI), and theICI result from the time variation of high speed channels. Simulation results show thatthe conventional algorithm can be used only in quasi-static channels and the proposedalgorithm can significantly improve the system performance in high speed channels. In chapter6, the contributions of this dissertation and the suggeations for futureresearches are summarized.