Soft handover refers to that a MS begins to connect with a new BS (Base Station), the communication between the mobile station and the former base station is still on. Soft handover is only applying to the CDMA cells with the same frequency.
Features of soft handover
- Seamless handover with no disconnection of the radio access bearer.
- To enable a sufficient reception level for maintaining communications by combining the received signal at symbol level from multiple cells in case the UE moves to the cell boundary areas.
- The macro diversity gain achieved by combining the received signal in the NODEB (softer handover) or in the RNC (SHO) improves the uplink signal quality and thus decrease the required transmission power of the UE.
The difference between soft handover and softer handover is, softer handover is performed in the same NodeB where the maximum gain ratio combination of diversity signals are implemented, while soft handover is performed between two NodeBs, diversity signals selective combination in RNC.