High Speed Packet Access (hspa)




Дата канвертавання21.04.2016
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High Speed Packet Access

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, HSPA+, is soon to be released.

The number of commercial 3.5G networks--also known as High-Speed Downlink Packet Access, or HSDPA, networks-- Almost two-thirds (62 percent) of existing commercial HSDPA networks support downlink speeds of 3.6 Mbit/s or more, while more than a fifth (21 percent) support the peak downlink speed of 7.2 Mbit/s.

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.

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.

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. 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.

Evolved High Speed Packet Access (HSPA+)

HSPA+ is defined in 3GPP release 7 . It introduces simpler IP centric architecture for the mobile network bypassing most of the legacy equipment. HSPA+ boosts peak data rates to 42 Mbit/s on the downlink and 22 Mbit/s on the uplink.

W-CDMA (Wideband Code Division Multiple Access) is a type of 3G cellular network. W-CDMA is the higher speed transmission protocol used in the Japanese FOMA system and in the UMTS system, a third generation follow-on to the 2G GSM networks deployed worldwide.

More technically, W-CDMA is a wideband spread-spectrum mobile air interface that utilizes the direct-sequence spread spectrum method of asynchronous code division multiple access to achieve higher speeds and support more users compared to the implementation of time division multiplexing (TDMA) used by 2G GSM networks.

Technical features - Radio channels are 5MHz wide.

Chip rate of 3.84 Mcps.- Supports two basic modes of duplex: frequency division and time division. Current systems use frequency division, one frequency for uplink and one for downlink. For time division, FOMA uses sixteen slots per radio frame, whereas UMTS uses fifteen slots per radio frame. Employs coherent detection on both the uplink and downlink based on the use of pilot symbols and channels. Supports inter-cell asynchronous operation. Variable mission on a 10 ms frame basis. Multicode transmission. Adaptive power control based on SIR (Signal-to-Interference Ratio). Multiuser detection and smart antennas can be used to increase capacity and coverage. Multiple types of handoff (or handover) between different cells including soft handoff, softer handoff and hard handoff.

Development

W-CDMA was developed by NTT DoCoMo as the air interface for their 3G network FOMA. Later NTT DoCoMo submitted the specification to the International Telecommunication Union (ITU) as a candidate for the international 3G standard known as IMT-2000. The ITU eventually accepted W-CDMA as part of the IMT-2000 family of 3G standards, as an alternative to CDMA2000, EDGE, and the short range DECT system. Later, W-CDMA was selected as the air interface for UMTS, the 3G successor to GSM.

Code Division Multiple Access communication networks have been developed by a number of companies over the years, but development of cell-phone networks based on CDMA (prior to W-CDMA) was dominated by Qualcomm, the first company to succeed in developing a practical and cost-effective CDMA implementation for consumer cell phones, its early IS-95 air interface standard. IS-95 evolved into the current CDMA2000 (IS-856/IS-2000) standard.

In the late 1990s, NTT DoCoMo began work on a new wide-band CDMA air interface for their planned 3G network FOMA. FOMA's air interface, called W-CDMA, was selected as the air interface for UMTS, a newer W-CDMA based system designed to be an easier upgrade for European GSM networks compared to FOMA. FOMA and UMTS use essentially the same air interface, but are different in other ways; thus, handsets are not 100% compatible between FOMA and UMTS, but roaming is supported.



Qualcomm created an experimental wideband CDMA system called CDMA2000 3x which unified the W-CDMA (3GPP) and CDMA2000 (3GPP2) network technologies into a single design for a worldwide standard air interface. Compatibility with CDMA2000 would have beneficially enabled roaming on existing networks beyond Japan.



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