Research Of The Beamforming Technology In The TD-LTE System

Beamforming is a kind of appling in small space of the antenna array transmissiontechnology. Beamforming technology using strong correlation of spatial channel andwave interferometric principle has strong directional orientation image, making themain lobe of orientation image adaptive toward wave direction of the user, so as toimprove the signal-to-noise ratio, and improve the system capacity or coverage.This paper makes a study of single-stream beamforming technology anddual-stream beamforming technology in the LTE system. Through the simulation ofdifferent beamforming weights method, the paper get a superior single-streambeamforming algorithm and dual-stream beamforming algorithm; The paper researchand analysis the influence of the particle degree weights, an antenna form, UE speedparameters of the single-stream beamforming and dual-stream beamforming. Theresearch found the eigenvalue algorithm is the best in the single-stream beamformingalgorithm. Results show that under the same conditions, the smaller the particle degreeof weights, the better the performance is; But the smaller of particle degree of weight,the higher complexity of the system is, accordingly in practical application, it is shouldtake a compromise between the system complexity and performance. It usually take12subordinate carrier as particle degree of weight; The better the correlation betweenantennas, the better the performance is. In the dual-stream beamforming algorithm, theeigenvalue decomposition algorithm performance is the best; The ideal channelestimation refers to the known accurate channel value, and the performance of the idealchannel estimation is better than not ideal channel estimation; In LTE system, channelmodel EPA is corresponding to low speed (0-10km/h), EVA is corresponding tomedium speed (10-120km/h), ETU is corresponding to high speed (120-350km/h).Different UE movement speed and the right channel model is associated.The paper research the dual-stream beamforming algorithm based on HARQ, andcomparison and analysis of the three kinds of algorithm. The results show that BLERperformance of algorithm3is the best. This is because the algorithm3onlytransmission the data which is wrong again, fully utilize the system resources, andgreatly improved the efficiency of the system, the other two algorithms not make fulluse of the resources, lead to low efficiency.