A low complexity scheme for realistic multi-cell downlink coherent joint transmission

As one of the key LTE-A technologies, coordinated multi-point transmission (CoMP) has been extensively investigated. Among various CoMP schemes, coherent joint transmission scheme (CJT) shows the largest CoMP gains in both cell average performance and cell edge performance. However, for pursuit of the upper bound of CoMP gains, centralized scheduling was adopted in those proposed CJT schemes. With CoMP cluster size increasing, those proposed CoMP schemes face multiple severe challenges, such as the unacceptable computational complexity and more strict latency requirements. In this paper, a novel CJT scheme is proposed, which is based on distributed scheduling and joint transmit precoder design. The complexity of the new CJT scheme is theoretically analyzed and compared with that of centralized scheduling CJT schemes. Moreover, comprehensive performance evaluations of the new CJT scheme are performed by system level simulations in various transmission scenarios. Taking the performance of non-CoMP scheme as baseline, the new CJT scheme can achieve over 35% cell average gain and over 32% cell edge gain, although there is around 10% cell edge CoMP gain loss than that of centralized scheduling CJT scheme.