13.6 Downlink CoMP Gains
The gain from CoMP on downlink performance is mainly in three major ways:
The second way doesn't include precise spatial domain information; therefore it can provide moderate but robust gain and can work on ordinary infrastructure. CS/CB and DCS are mainly focusing on the second benefit while joint transmission is focusing on the first benefit. The third benefit can be significant at the cell edge (e.g. some implementations may operate with effective handover margins of 3–4 dB) but over time distributed solutions will also be optimized and will find ways to squeeze the effective handover margins. The CoMP gains mechanisms are shown in Table 13.6.
Figure 13.8 summarizes the observed CoMP gains over Release 8 2 × 2 SU-MIMO, where several downlink CoMP schemes were simulated ...