Investigation Of User Pairing Algorithms In The Virtual MIMO System

With the development of mobile internet and multi-media service, the requirement of the wireless systems capacity increased rapidly, however, due to the already tight trapped time/frequency resource, how to improve the data transmission rate in a more efficient way has always been one of the most active subjects in the digital wireless communication systems researches.The scientific research has confirmed that:the communication systems capacity can be dramatically promoted by spatial multiplexing by MIMO. Hence, MIMO has been used in downlink transmission as a must-option in LTE system. Meanwhile, the researches of the Virtual MIMO system for uplink are also very hot. Among these, the studies focused on user pairing algorithm which is the key technology in Virtual MIMO system have achieved promising results in introducing new or improved algorithms.Virtual MIMO is such a technology that selects a group of UEs by a specific algorithm. And then let them to transmit data using the same time/frequency resource. Because the many antennas can transmit simultaneously, so the transmitting antenna array is formed just like MIMO in uplink. However when it is implemented, the UEs still only equip one antenna, the combining transmission is only conducted by a specific scheduling algorithm. Using this technology, the MIMO-like system can be formed in uplink without any expenditure either in UEs or wireless resources. Therefore, it has a positive improvement in resource efficiency and capacity increasing. This paper focused on the research of user pairing algorithm in Virtual MIMO. On the basis of the current studies, our aim is to analyze different algorithms'features and system performance by using theoretical analysis and simulation. The main work has achieved are listed as follow:1. Within the performance requirement of LTE system and the specific technical character of MIMO system, systematic study of theory and technical was carried about the Virtual MIMO system.2. Based on the results of domestic and international researches, primal analysis and research were focused on 4 user pairing algorithm in Virtual MIMO.3. By programming simulation platform, simulation results were gotten in systems average channel capacities, further comparison and analyses were carried out between different algorithms.4. Referring to the unpleasant performance of OPS, two modifications are proposed.With the above researches, besides the performance analysis between algorithms, two amendments of OPS were proposed and their efficiencies were also verified.