Connectivity Explained
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Vodafone has announced it will launch HSDPA services during summer 2006. Vodafone released their HSDPA laptop data card on 22 June 2006. The card comes in two versions; tri-band and quad band and will work with Vodafone's 3G/HSDPA network in several other countries including Austria, France, Germany, Portugal, Spain and Hong Kong.
O2 will launch their HSDPA services across the UK in the third quarter of 2006. O2 expects initial download speeds to be 3.6 Mbit/s at launch, increasing to 7.3 Mbit/s by early 2008, and reaching 10.2 Mbit/s by late 2009.
Orange UK has announced they will be rolling out their HSDPA service in the second half of 2006.
T-Mobile UK has announced that their HSDPA network will go live across the UK on 1 August 2006. Initial download speeds were announced to be 1.8Mbps, rising to 3.6Mbps in 2007, 7.2Mbps in 2008, 10Mbps in 2009 and 20Mbps by 2011.
General Packet Radio Service (GPRS) is a mobile data service available to users of GSM mobile phones. It is often described as "2.5G", that is, a technology between the second (2G) and third (3G) generations of mobile telephony. It provides moderate speed data transfer, by using unused TDMA channels in the GSM network. Originally there were plans to extend GPRS to cover other standards, but instead those networks are being converted to use the GSM standard so that is the only kind of network where GPRS is in use. GPRS is integrated into GSM standards releases starting with Release 97 and onwards.
Packet-switched data under GPRS is achieved by allocating unused cell bandwidth to transmit data. As dedicated voice (or data) channels are setup by phones, the bandwidth available for packet switched data shrinks. A consequence of this is that packet switched data has a poor bit rate in busy cells. The theoretical limit for packet switched data is approx. 160.0 kbit/s (using 8 time slots and CS-4). A realistic bit rate is 30–80 kbit/s, because it is possible to use max 4 time slots for downlink. A change to the radio part of GPRS called EDGE (sometimes called EGPRS or Enhanced GPRS however it actually stands for Enhanced Data rates for GSM Evolution) allows higher bit rates of between 160 and 236.8 kbit/s. The maximum data rates are achieved only by allocation of more than one time slot in the TDMA frame. Also, the higher the data rate, the lower the error correction capability. Generally, the connection speed drops logarithmically with distance from the base station. This is not an issue in heavily populated areas with high cell density, but may become an issue in sparsely populated/rural areas.
Enhanced Data rates for GSM Evolution, or EDGE, is a digital mobile phone technology which acts as a bolt-on enhancement to 2G and 2.5G General Packet Radio Service (GPRS) networks. This technology works in GSM networks. EDGE (also known as EGPRS) is a superset to GPRS and can function on any network with GPRS deployed on it, provided the carrier implements the necessary upgrades.
EDGE provides Enhanced GPRS (EGPRS), which can be used for any packet switched applications such as an Internet connection. High-speed data applications such as video services and other multimedia benefit from EGPRS' increased data capacity. EDGE Circuit Switched is a possible future development.
EDGE can carry data speeds up to 236.8 kbit/s for 4 timeslots (theoretical maximum is 473.6 kbit/s for 8 timeslots) in packet mode and will therefore meet the International Telecommunications Union's requirement for a 3G network, and has been accepted by the ITU as part of the IMT-2000 family of 3G standards. It also enhances the circuit data mode called HSCSD, increasing the data rate of this service. EDGE has been introduced into GSM networks around the world since 2003.
High-Speed Downlink Packet Access (HSDPA) is a new mobile telephony protocol and is sometimes referred to as a 3.5G (or "3½G") technology. In this respect it extends WCDMA in the same way that EV-DO extends CDMA2000. HSDPA provides a smooth evolutionary path for Universal Mobile Telecommunications System (UMTS) networks allowing for higher data capacity (up to 14.4 Mbit/s in the downlink). It is an evolution of the W-CDMA standard, designed to increase the available data rate by a factor of 5 or more. HSDPA defines a new W-CDMA channel, the high-speed downlink shared channel (HS-DSCH) that operates in a different way from existing W-CDMA channels, but is only used for downlink communication to the mobile.
Plans for HSDPA deployment:
