Study Of The Key Technologies In Coordinated Multi-Piont Transmission And Reception

The frequency reuse factor of LTE-A system is one, which can effectively improve the spectrum efficiency. However, this will increase the system interference, thus will damage the performance of cell edge users. CoMP (Coordinated Multi-Point Transmission and Reception) can suppress the interference and even turn the interference into useful signal through the sharing of channel state information and/or user data information among multiple cells, thus can effectively deal with the interference problem in cellular network, which is one of the key technologies in LTE-A system.This paper mainly studied the network architecture supporting this CoMP technology and the influence on CoMP performance caused by delay.The implementation of CoMP technology needs to be based on certain network architecture. This paper analyzed three synchronization requirements on CoMP network architecture, including the clock synchronization, the MAC layer synchronization and the data synchronization. Then two kinds of network architecture were described. They were centralized CoMP in which information is centralized controlled and distributed CoMP in which information is shared via the interaction between coordinated nodes. A modified distributed CoMP was proposed based on the above two forms to simplify the cooperation procedure. Finally, the impress of CoMP on cell selection process and data transmission were analyzed.In practical CoMP scenario, the performance of the backhaul link is non-ideal, so the information interaction between COMP node will inevitably bring delay, which will reduce the performance gain brought by CoMP technique. This paper analyzed the factors that affect delay, including X2interface performance, CoMP mode, CoMP backhaul network topology and media, method of user data pre-coding and acquisition. By building corresponding system model, this paper analyzed the performance degradation caused by the aging channel state information based on the non-ideal backhaul link from the point of theory. The simulation test was done by adding the delay module on the basis of the LTE system level simulation platform provided by Vienna University, as well as some modification in schedule module and channel module. This paper then pointed out the drawbacks of the traditional centralized CoMP scheme like the heavy load on Central Unit and the indiscrimination between CoMP users and non-CoMP users when scheduling and then proposed a modified scheme. The following simulation results proved that the proposed scheme had some improvement on delay and system performance.