Enhanced multi-cell coordination in wireless communication system using beamforming methods

Abstract

A novel CoMP architecture design was proposed via the innovative division of an LTE cell into three spatial regions. The proposed technique is called Hybrid Cell Downlink Optimization (HCDO). This technique focuses on increasing the throughput and the capacity over the cell area. Moreover, the HCDO technique focuses on increasing the deployment coverage area based on the presence of transmission power while reducing the backhaul signaling overhead using the beamforming algorithm. The Minimum Variance Distortionless Response (MVDR) beamformer is the best known beamforming algorithm. Unfortunately, MVDR is very sensitive to steering vector errors, and in the event it occurs, the desired signal could be suppressed. Thus, two beamforming methods were proposed in this thesis for the purpose of modifying and enhancing the performance of the current MVDR beamforming algorithm. These proposed methods, namely, Modified MVDR (MMVDR) and Sub-Space Interference Cancelation MVDR (SSIC-MVDR), focus on increasing the rigidity of MVDR against steering vector errors caused by calibration or manufacturing errors. The performance evaluations, comparisons, and analysis showed that the MMVDR and SSIC-MVDR algorithms are less complex methods, which reduces the cost (number of antennas) by more than 61.5 % and reduce the processing time by reducing the number of snapshots to 99%. Also, the results showed that the incorporation of SSIC-MVDR into HCDO technique improved the transmission signal quality, where the average cell users’ signal modulated with QAM scheme, and improved the cell sector throughput by 136.99%. Moreover, the signaling overhead and response latency were reduced, since the CoMP base station became capable of generating the beamforming weight without help from CU.