UMTS is an umbrella term for the third generation radio technologies developed by the 3GPP. UMTS specifies a complete network system, for which the radio access component, known as UTRAN, uses WCDMA technology to offer greater spectral efficiency and bandwidth to mobile network operators. The system also includes the Core Network; the entity that interfaces to external networks including the public phone network and other cellular telecommunications networks.
Packet Data Protocols
Since UMTS was introduced in 3GPP R99 the need for improved support for downlink data services has increased. High Speed Packet data Access (HSPA) has been an upgrade to WCDMA networks (FDD and TDD) used to increase packet data performance. The introduction was done in steps; High Speed Down Link (DL) Packet data Access (HSDPA), was introduced in 3GPP Release 5, and Enhanced Up Link (UL), also referred to as High Speed UL Packet data Access (HSUPA), came in Release 6.
The combination of HSDPA and HSUPA is referred to as HSPA. HSPA evolution known as HSPA+ came in Release 7 with further improvements in later releases.
Dual-Carrier HSPA+ capability was introduced by 3GPP in the Release 8 specifications, and enables a theoretical peak downlink data throughput capability of 42 Mbps. DC-HSPA+ systems combine 64QAM modulation and double the bandwidth by using dual carriers (2 x 5 MHz = 10 MHz). To improve uplink data rates, the implementation of 16QAM over QPSK modulation made it possible to double peak data rates to 11.5 Mbps. Dual-Carrier technology further extended uplink performance to 23 Mbps.