ransmission (JT) or dynamic point selection (DPS) which is also known as dynamic cell selection (DCS). DPS is a simple but effective downlink CoMP scheme that switches the serving transmission point to the UE based on the UE's channel estimate feedback and the cell loading conditions. The switching can be done very fast even on subframe-to-subframe basis without any handover signalling. It provides both macro diversity and fast load balancing gains. The macro diversity benefit is obtained by choosing the best serving transmission point according to the UE's current channel conditions. Fast load balancing gains are realized by transmitting to the UE from the less-loaded transmission point. The UE estimates the CSI from up to three cells. LTE Small Cell Optimization CoMP gains in downlink DPS in macro DPS in HetNet Cell edge gain % Avg gain % Figure 7.35 CoMP gains in downlink with dynamic point selection (DPS) Figure 7.35 shows the gains with DPS both in three-sector macro cell environment and in HetNet scenario, with ideal backhaul assumed between the baseband units. The cooperation cluster is assumed to include the immediate neighbours of each cell. The selected algorithm is described in more detail in [10]. The cell edge gain in the macro cell is 75% and in HetNet case about 50% which illustrates the power of DPS solution. There is even a small gain in the average data rate. These results assume a realistic handover margin of 2 dB, and DPS is able to fully overcome the negative effects of handover margin. The gains for the HetNet case are slightly smaller because the baseline with RE and eICIC mechanisms provides much of the load balancing gains. The CoMP performance factors are discussed in [11]. 3GPP CoMP simulations can be found from [12]. DPS solution can be implemented with reasonably low backhaul requirements - no need for centralized baseband. UE's RRC connection and the S1 connection stay at its anchor eNodeB while its serving transmission point can be switched rapidly within CoMP set. If the current se