The Research Of HARQ Base On HSDPA System

In order to improve the ability of high-speed of data transmission and enhance the competitiveness of mobile communications of the third generation mobile communication system (TD-SCDMA), the 3GPP proposed high-speed downlink packet access (HSDPA) technology in Release5. The aim of the High Speed Downlink Packet Access is to meet the demand of up/down asymmetry of the data services, in the same time, it can greatly improve the downlink capacity of the entire system and data services transmission rates. In order to achieve high-speed data transportation ability,3G communication adopts the techniques such as adaptive modulation and coding,hybrid automatic repeat request,fast cell selection,packet scheduling techniques in the HSDPA system. This paper introduced determinedly the key techniques of the HSDPA system—HARQ, which are used in the TD-SCDMA mobile communication system based on the principle of HSDPA and the research of background technology。This paper described the Protocol Structure of the HSDPA system and the key technology, and also analyzed the advantages of TD-SCDMA. The maximum theoretical data rate realized by the TDD mode adopted by the Multi-carrier TD-SCDMA HSDPA system proved further that the TD-SCDMA HSDPA spectrum is higher. This paper mainly analyzed deeply the three basic types and retransmission of the mixed automatic retransmission request, and the application in the physical and function realization in HSDPA system etc, and based on this, put forward an improved CQI assisting HARQ scheme strategies and did simulation and analysis. The simulation results showed that improved CQI assisting HARQ scheme has greatly improved the Throughput and data retransmission, and also can reduce the data transmission delay and improve the capacity of the system. This paper simulated and analyzed different HARQ scheme under the conditions of walk and vehicle channel, and got the best HARQ scheme in different environment and conditions, so it not only can improve data transportation rate,increase throughput,reduce delay, but also can improve the capacity of the whole system。...