An Enhanced Coherent Joint Transmission Algorithm for Multi-Cell Downlink Transmission

Coherent joint transmission (CJT) algorithm has been extensively investigated in multi-cell cooperative downlink transmission due to its huge potential performance gains. Comparing with the existing CJT algorithm based on the multi-user eign-mode transmission, an enhanced CJT (eCJT) algorithm is proposed in this paper to further enhance the performance of cellular network in terms of spectral efficiency, especially for the cell edge users. Theoretical analysis show that utilizing successive transmit channel optimization and selection, eCJT outperforms traditional CJT in multi-cell coordinated joint transmission. System level simulation results demonstrate that eCJT algorithm outperforms traditional CJT algorithm in both cell average performance and cell edge performance. Taking the performance of traditional CJT algorithm as the baseline, eCJT algorithm can achieve over 30% spectral efficiency gain in cell edge under ITU UMi and 3GPP Case1-3D scenario, respectively.