Capacity gains from multipoint single frequency transmission in HSPA+

High Speed-Single Frequency Network (HS-SFN) is one of the possible multipoint transmission techniques proposed in the 3GPP standard for High Speed Downlink Packet Access (HSDPA) in order to improve network performance, especially at the cell edge. It allows neighboring cells to transmit simultaneously the same data stream to a User Equipment (UE) in the Handover region (HO). In order to evaluate the user-level performance of this technique, we develop a method based on network simulation coupled with Markov chain analysis. It shows that when the HS-SFN technique is performed in the HO region between adjacent cells, the user data rates increase significantly. However, this is true only when involved cells are partially loaded, which is not always the case. We thus propose an optimized approach that adapts the coordination area based on the average offered traffic observed in the network. Network performance is then improved at any load.