Enhanced HSDPA Mobility Performance: Quality and Robustness for Voice Over HSPA Service
Legacy High Speed Downlink Shared Channel (HS-DSCH) Serving Cell Change (SCC) procedures in deployed HSPA networks (3GPP Release 5 and 6) may lead to unacceptably high call drop rates in realistic Urban Canyon conditions when Signaling Radio Bearers (SRBs) are mapped on the HS-DSCH. Mapping SRB on HS-DSCH is necessary to enable high capacity voice over HSPA (Circuit Switched Voice or VoIP over HSPA) since it eliminates the code limitation that arises when SRBs are mapped on DCH. To address the above robustness issue, Enhanced SCC (ESCC) was introduced in 3GPP Release 8. In this paper, the authors highlight the first ever implementation of the E-SCC algorithm in a HSPA prototype system.