Research on Uplink User Performance of Virtual MIMO in WiMAX System
|School||Harbin Institute of Technology|
|Course||Information and Communication Engineering|
|Keywords||WiMAX system virtual MIMO MIMO channel estimation SIC decoding arithmetic Resouce-sharing Scheduling methods|
Future mobile service will be getting a increasing higher request of the quality of service and speed of transmission. We must use a kind of advanced technology to use the precious frequency resources effectively in order to satisfy the high speed and the large capacity service demands. Simultaneously overcomes the decline of high speed data under wireless channel’s multi-paths, the noise reduction and the multi-paths disturbance and achieves the target of system performance improvement. The MIMO-OFDM system has solved this difficult problem effectively. It not only raised the frequency spectrum using efficiency and the power efficiency, but also has used the multi-paths decline and the disturbance effectively. As the single antenna terminal device is unable to realize upward MIMO independently, we considered that let two or more terminal form a group, which uses the same time-frequency resources to carry on the upward transmission. The respective antenna is similar to the identical terminal with many antennas, thus we can realized upward MIMO. This method is called virtual MIMO.This paper’s main researching content is how to enhance the virtual MIMO performance based on WiMAX system. During the researching process a lot of domestic and foreign technology literature about MIMO and OFDM has been referred to as well as the virtual MIMO and two aspects has been emphasized on. On one hand is physics level channel estimate and the decoding algorithm research of the virtual MIMO system, which proposed several commonly used channel estimate method and receiving decoding algorithm which is carried on in the virtual MIMO system as the application. Through the simulation of SNR-BER curve an algorithm called SIC with lower complexity and better performance finally is applied in the virtual MIMO system. The research on the other hand was aims at the MAC level scheduling plan of virtual MIMO. First introduced several virtual MIMO pairing methods, the different method has the different suitable environment. Afterward a scheduling flow for virtual MIMO system was given as a flow chart. This scheduling plan’s core thought is the resource sharing which enhanced the upward throughout of virtual MIMO system greatly under the premise that other performance are not changed.