The Research Of HARQ In TD-HSDPA

TD-HSDPA which stands for high speed downlink packet access in TD-SCDMA is an enhanced technique of the 3rd generation mobile communication standard. The purpose of introducing this technique is facing the increasing data communication service and strengthening the competition of the standard. For achieving high data rate communication, besides the improved architecture and techniques such as AMC and HARQ.Based on the discussion of the principle and backgrounds of HSDPA,the applications of HARQ in HSDPA for TD-SCDMA system are studied in this thesis.In the thesis, the key technologies of the HSDPA system are analyzed, and the similarities and differences of the TD-HSDPA and W-HSDPA are compared. Deducing the highest rate that could be achieved in multi-carrier TD-HSDPA, furthermore, it proves that TD-HSDPA is more advantage than W-HSDPA in the spectrum efficiency. Hybrid ARQ type, working mechanism, application etc are researched, an improved CA-HARQ program is put forward, which based on channel current situation determining the initial parity bit, meanwhile carrying out a simulation, which show that the new programs introduced can reduced retransmission number and data transmission delay with the throughput rate uncharged basically.The throughput of various modulation coding schemes at different types of HARQ is simulated through PA3 and VA30 channel, it could obtain that the optimal use range and optimal HARQ type around different modulation coding scheme. The simulation concludes that changing Node B side modulation coding scheme can improve system throughout with the change in signal to noise ratio; choosing an appropriate HARQ scheme may be able to further improve data transfer rate to a fixed modulation coding scheme.