Overview
3.5G technology or HSPA technology is a collection of HSUPA (High-Speed Uplink Packet Access) and HSDPA (High-Speed Downlink Packet Access) mobile telephony protocols that improves and extends the current UMTS (Universal Mobile Telecommunications System) and WCDMA (Wideband Code Multiple Division Access) protocols performance. It promises the streaming of live television and music videos, plus fast wireless access to the Internet through mobile handsets.
3.5G technology has been commercially set up in over 80 countries by more than 200 operators. It supports increased data transfer rates of 5.8 Mbps (Megabits per second) in the uplink and 14 Mbps (Megabits per second) in the downlink. HSPA increases capacity and peak data transfer rates in many ways –
• It uses shared and multi-code channel transmission for better use of power resources and available code in WCDMA.
• It uses a shorter TTI (Transmission Time Interval) to reduce round trip time.
• It uses link adaption for maximizing channel usage.
• It uses soft-combining and fast retransmission to increase the capacity.
HSUPA or High-Speed Uplink Packet Access
It is an uplink evolution technology in WCDMA / UMTS networks. The specification of HSUPA is included in release 6 by 3GPP. The HSUPA technology is directly linked to HSDPA technology, and the two are flattering to one another. It appears that HSDPA technology is more advanced than the HSUPA technology, but they can be used alongside which will result in higher data transfer speed for receiving or sending the data. It increases the capacity and data rate to 5.8 Mbps, and also decrease latency. It creates many opportunities (like uploading pictures and videos) for new applications (including Voice over IP).
HSDPA or High-Speed Downlink Packet Access
HSDPA provides a smooth evolutionary path for UMTS / WCDMA networks in achieving the high-speed and higher data capacity. In the release 5, 3GPP (3rd Generation Partnership Project) defined the first phase of HSDPA. It is intended to achieve the data transfer rates of 14 Mbps (Megabits per second).
Current HSDPA deployments support downlink speeds of 1.8, 3.6, 7.2 and 14 Mbps with considerably reduced latency. Its main features are multi-code and shared channel transmission, short TTI, fast scheduling, higher-order modulation and fast link adaption. Approximately, 90 percent of the WCDMA/UMTS networks have been upgraded to HSDPA technology.
DC-HSDPA (Dual-Cell HSDPA) and DC-HSUPA (Dual-Cell HSUPA)
DC-HSUPA and DC-HSDPA is defined in release 8 and 9 by 3GPP, are natural evolutions of HSPA technology by implying carrier aggregation in the uplink and downlink. HSPA+ supports single 5 MHz carrier, but DC-HSDPA and DC-HSUPA doubles the bandwidth from 5MHz to 10 MHz.
HSPA+
In the release 7 and 8, 3GPP defined the Evolved High-Speed Packet Access (also referred as I-HSPA (Internet HSPA), HSPA Evolution, HSPA+). It is a forthcoming wireless network standard, which provides data transfer rates up to 11 Mbps in the uplink and 42 Mbps in the downlink with a single 5 MHz carrier. It also supports higher order modulation and MIMO (multiple inputs, multiple outputs) technologies.