High speed packet access (HSPA) was included in the Third Generation Partnership Project (3GPP) Releases 5 and 6 for downlink and for uplink. The 3GPP Releases 7, 8 and 9 have brought a number of HSPA enhancements providing major improvements to the end user performance and to network efficiency. The work continues further in Release 10. The HSPA evolution work has progressed in parallel to LTE work in 3GPP. Many of the technical solutions in HSPA evolution and LTE are also similar. The overview of the roles of the HSPA evolution and LTE is illustrated in Figure 15.1. HSPA evolution is optimized for co-existence with WCDMA/HSPA supporting legacy Release 99 UEs on the same carrier and designed for simple upgrade on top of HSPA. The HSPA evolution aims to improve the end user performance by lower latency, lower power consumption and higher data rates. HSPA evolution includes also interworking with LTE which enables both packet handovers and voice handovers from LTE voice-over IP (VoIP) to HSPA circuit switched (CS) voice.
The HSPA evolution features are introduced in this chapter. The HSPA evolution is also known as HSPA+. This chapter covers other parts of HSPA evolution except for Dual cell and multicarrier HSPA, covered in Chapter 16.
15.2 Discontinuous ...