Performance Analysis Of Resource Allocation In Network MIMO Systems

Network MIMO transmission technology plays an important role in making full use of spatial resources and increasing system performance, it can help to effectively improve the signal to noise ratio of the cell edge users. However, in practical applications, network MIMO still faces many problems and challenges. The main work of this paper is based on the resource allocation problems in practical network MIMO systems.Firstly, the LTE network MIMO system resource allocation and interference cancellation techniques are studied. Resource allocation solutions in LTE downlink environment are discussed, such as beamforming. To study the performance of those resource allocation solutions, a LTE downlink simulation platform were built according to 36.101 standard, and beamforming solution were simulated on this platform. To cancellate the inter-channel interference, interference cancellation techniques in receiver were discussed, including interference rejection combining (IRC) and interference whitening. To improve the robustness of the interference whitening algorithm and reduce the performance loss that interference whitening algorithm brings to systems without interference, this paper proposed an improved scheme that making unit correction for the interference autocorrelation matrix. Through this approach, the performance loss can be reduced or even eliminated.Secondly, to increase indoor network performance,802.11 networks and the resource allocation methods in 802.11 WLAN were discussed, the resource allocation methods discussed were mainly about load balancing and access control. In terms of load balancing, several load balancing approaches were introduced, and simulated in a 802.11 simulation platform. To make better resource allocation in a overloaded AP, a new TDMA access control mechanism was proposed. In TDMA access control mechanism, if AP was overloaded, each user can occupy the channel in its own time slot. The simulation result showed this mechanism can significantly improve the system throughput.In the end, in order to verify the actual performance of TDMA approach, this mechanism was implemented in router hardware platform by modifying.OpenWRT software. The driver and Linux kernel were modified in order to implement this mechanism. The OpenWRT drive boot process and the process of sending and receiving data were discussed. Besides, the way of slot division, modification method of Beacon frame, STA information recording method were proposed. Based on that, this paper proposed two TDMA implementing solutions, and analysed them through hardware test.