The Research Of Virtual Multiple-input Multiple-output For The Uplink Of LTE System

In wireless communication systems, Multiple-input-multiple-output (MIMO) technology can greatly increase the system capacity and spectral efficiency by the arrangement of multi-antenna in the transmiter and the receiver.MIMO technology can be broadly divided into two categories:transmit diversity and spatial multiplexing.In spatial multiplexing,independent data streams can be launched from each individual transmit antenna.The mixed signals can be distinguished at the receiving side,provided that the number of receive antennas is not less than of transmit antennas.The purpose of spatial multiplexing is to increase the system capacity and spectral efficiency.Based on the superior performance of the spatial Multiplexing MIMO systems, a number of virtual MIMO (VMIMO) theories have been proposed by researchers. Currently an idea called non-cooperation virtual MIMO being discussed by 3GPP LTE (3rd Generation Partnership Project Long Term Evolution). NVMIMO selects multiple UEs by the BS to enable them to share their channel information while the UEs in the system don't need to have the ability to communicate directly. The system capacity can be greatly improved due to the paired two UEs use the same radio resource in the uplink, although it is not fair for individual UE since it will increase the bit error rate (BER). Therefore, how to pair up multiuser properly is one of the major problems for NVMIMO pairing scheduling.In this paper, the algorithm of multiuser pairing-up for a LTE uplink in virtual MIMO system is studied. Based on analyzing the two SUP algorithms, named coorelative angle-based SUP (CA-SUP) and Frobenius norm-based SUP (FN-SUP) schemes, then combination of SC-FDMA and MIMO, The two algorithms in a simulation study in the case of a fixed power allocation and adaptive power allocation.And then on this basis, the improved CA-SUP algorithm based on the SINR threshold and integration of scheduling algorithms improve fairness and increase system capacity with a good performance.