Research On Adaptive Coded Modulation Technology And Its Appliaction In HSDPA

Future mobile communications have to support the transmission of high rate data and multimedia applications in the radio spectrum, which is already extremely scarce. The basic idea of Adaptive Coded Modulation is to maintain a constant throughput by varying the transmitted power level, symbol transmission rate, constellation size, coding rate or any combination of these parameters. Thus, without sacrificing bit-error rate (BER), these schemes provide high average spectral efficiency by transmitting at high speeds under favorable channel conditions, and reducing throughput as the channel degrades.After a brief introduction of the fade of wireless channel and the technology of estimation of channel and SNR, the basic principles of the Adaptive Coded Modulation and an optimal design scheme of average spectral efficiency in adaptive coded modulation system are mainly investigated. Then, the application of Adaptive Coded Modulation in HSDPA is briefly discussed.According to the information that reflected the condition of channel, this thesis classified ACM into heuristic ACM and SNR-estimation ACM. The system that using the first one of ACM decide the scheme of modulation and coding according to the frame error ratio that reflected indirectly the condition of channel, while it using the another of ACM decide the scheme according to the SNR estimation. In this thesis, we compared the two ACM through simulation, and analyzed their merits and flaws. Then we present an optimal design scheme of average spectral efficiency in adaptive coded modulation system.HSDPA is a good improvement and evolvement in the wireless part of WCDMA. ACM is one of the key technologies in HSDPA, and H-ARQ is a recessive technology of ACM. In the end of this thesis, the basic principle of H-ARQ and its class are briefly discussed. Then we investigate the application of ACM in HSDPA and the complexity of the equipment using ACM in HSDPA.The simulation results show that adaptive coded modulation technique is an efficiency methods to provide a high spectral efficiency, combined with H-ARQ, it can maintain an acceptable transmission quality and make a good advantage of...