Coordinated Multipoint Trials in the Downlink

Coordinated multi-point (CoMP) is a new class of transmission schemes for interference reduction in the next generation of mobile networks. We have implemented and tested a distributed CoMP transmission approach in the downlink of an LTE-Advanced trial system operating in real time over 20 MHz bandwidth. Enabling features such as network synchronization, cell- and user-specific pilots, feedback of multicell channel state information and synchronous data exchange between the base stations have been implemented. Interference-limited transmission experiments have been conducted using optimum combining with interference-aware link adaptation and cross-wise interference cancellation between the cells. The benefits of CoMP transmission have been studied over multi-cell channels recorded in an urban macro-cell scenario.