tive delivery alternative to its predecessor, ATM. End-to-End (Quality of Service) (QoS) for PS Domain: 3GPP Rel-5 defines QoS in TS 23.207 which provides a framework for end-to-end Quality of Service. From the 3GPP perspective, the focus of end-to-end QoS is on the UMTS Bearer (packet data) service only. 3.2.4 Key Aspects of Rel-6 The Rel-6 enabled the counterpart of HSDPA that is, HSUPA, to support higher data rates in the uplink. A high level description of HSUPA (High Speed Packet Access) and other key features is as follows [5]: HSUPA: HSUPA will bring peak data rate of 5.76 Mbps in uplink to the family of UMTS. HSUPA is using an Enhanced Dedicated Channel (E-DCH) on which it employs 16-QAM and H-ARQ3 3 support higher data rates. 2 Tandem Free Operation is a configuration of a speech or multimedia call for which transcoders are not utilized but are present. Transcoder Free Operation is a configuration of a speech or multimedia call for which transcoders are not present in the communications path. 3 HARQ uses incremental redundancy, where user data is transmitted multiple times using different codings. When a corrupted packet is received, the user device saves it and later combines it with the retransmissions, to recover the 3GPP Evolved Packet System (EPS) Receive Diversity: Rel-6 enables receive diversity or multiple receive antennas for HSDPA terminals. The receive diversity improves the capacity of the UMTS networks. Support for MBMS: Another major enhancement is called Multimedia Broadcast and Multicast Service. MBMS is a broadcasting service and is a means of delivering Mobile TV to multiple viewers via UMTS networks. IMS Phase 2: The main developments for IMS include IP IMS messaging, interworking between IMS and circuit switched and non-IMS IP networks and IMS charging. 3.2.5 Key Aspects of Release 7 Release 7 introduces Evolved HSPA (HSPA+), enhancements to IMS, MBMS, and SO on. The details can be found in [6]. HSPA- Release 7 enables HSPA+ that supports peak data rates of 28 Mbps in the downlink and