High-Speed Packet Access
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Categories: Articles lacking sources from January 2008 | All articles lacking sources | Mobile phone standards | High-Speed Packet Access | Universal Mobile Telecommunications System
vi:Tiêu bản:Chuẩn điện thoại di động High-Speed Packet Access (HSPA) is a collection of mobile telephony protocols that extend and improve the performance of existing UMTS protocols. Two standards, HSDPA and HSUPA, have been established and a further standard, HSOPA, is being proposed.
OverviewThe two existing standards (HSDPA and HSUPA) in the family provide increased performance by using improved modulation schemes and by refining the protocols by which handsets and base stations communicate. These improvements lead to a better utilization of the existing radio bandwidth provided by UMTS. The number of commercial 3.5G networks--also known as High-Speed Downlink Packet Access, or HSDPA, networks--launched worldwide grew by 69 percent in 2007. There are now 174 commercial HSDPA networks in 76 countries. An additional 38 networks are committed to rollouts, which will bump the total to 211 HSDPA networks in 90 countries. Commercial HSDPA networks are widely available in Western Europe (61 networks), Southeast Asia (35), Eastern Europe (34), the Middle East and Africa (20), and the Americas and the Caribbean (16). Almost two-thirds (62 percent) of existing commercial HSDPA networks support downlink speeds of 3.6Mbps or more, while more than a fifth (21 percent) support the peak downlink speed of 7.2Mbps.[1] Many HSPA rollouts can be achieved by a software upgrade to existing 3G networks, giving 3.5G a headstart over WiMax, which requires dedicated network infrastructure. Rising sales of HSPA-enabled mobiles--aided by more-generous-than-expected operator subsidies of the hardware--are helping to drive the 3.5G market.[2] High Speed Downlink Packet Access (HSDPA)HSDPA provides improved theoretical down-link performance of up to 14.4 Mbit/s. Existing deployments provide up to 7.2 Mbit/s in down-link. Up-link performance is a maximum of 384 kbit/s. For operational reasons, service providers may cap this rate to lower rates than the maximum 3.6 Mbit/s that most HSDPA handsets can transfer at. Voice calls are usually prioritized over data transfer. The Croatian VIPnet network supports the speed of 7.2 Mbit/s in down-link. In South Korea, a nationwide 7.2Mbit/s coverage is now established by SK Telecom and KTF. In Hong Kong, PCCW also provide 7.6Mbit/s coverage. High Speed Uplink Packet Access (HSUPA)HSUPA provides improved up-link performance of up to 5.76 Mbit/s theoretically. In Singapore, Starhub announced a 1.9 Mbit/s HSUPA Service as part of its new MaxMobile plan in 1 Aug 2007 [1]. In Finland, Elisa announced on 30.8.2007 1.4 Mbit/s HSUPA to most large cities with plans to add the service to its whole 3G network within months [2]. Evolved High Speed Packet Access (Evolved HSPA, HSPA Evolved, HSPA+, I-HSPA,...)Evolved HSPA is defined in 3GPP release 7 (expected in 2007). It introduces simpler IP centric architecture for the mobile network bypassing most of the legacy equipment and enhances radio data rates. High Speed OFDM Packet Access (HSOPA)HSOPA is currently under development, aiming for maximum transfer rates of 100 Mbit/s for down-link and 50 Mbit/s for up-link. References
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