(Redirected from HSDPA)
'High-Speed Downlink Packet Access' ('HSDPA', also known as 'High-Speed Downlink Protocol Access') is a
3G (third generation)
mobile telephony communications protocol in the
High-Speed Packet Access (HSPA) family, which allows networks based on
Universal Mobile Telecommunications System (UMTS) to have higher data transfer speeds and capacity. Current HSDPA deployments support down-link speeds of 1.8, 3.6, 7.2 and 14.4 Mbit/s, and can provide each customer with 30 gigabytes of data per month.
[How to realise the benefits of mobile broadband today Global System for Mobile Communications (GSMA) publication. 2007] Further speed increases are planned for the near future. The networks are then to be upgraded to
Evolved HSPA, which provides speeds of 42 Mbit downlink in its first release.
Technology
The High-Speed Downlink Shared Channel (HS-DSCH) lacks two basic features of other W-CDMA channels — variable spreading factor and fast power control. Instead, it delivers the improved downlink performance using
adaptive modulation and coding (AMC), fast packet scheduling at the base station, and fast retransmissions from the base station, known as hybrid automatic repeat-request (HARQ).
Hybrid automatic repeat-request (HARQ)
HARQ uses incremental redundancy, where user data is transmitted multiple times using different codings. When a corrupted packet is received, the user device saves it and later combines it with the retransmissions, to recover the error-free packet as efficiently as possible. Even if the retransmitted packets are corrupted, their combination can yield an error-free packet.
Fast packet scheduling
The HS-DSCH downlink channel is shared between users using channel-dependent scheduling to make the best use of available radio conditions. Each user device periodically transmits an indication of the downlink signal quality, as often as 500 times per second. Using this information from all devices, the base station decides which users will be sent data on the next 2 ms frame and how much data should be sent for each user. More data can be sent to users which report high downlink signal quality.
The amount of the channelisation code tree, and thus network bandwidth, allocated to HSDPA users is determined by the network. The allocation is "semi-static" in that it can be modified while the network is operating, but not on a frame-by-frame basis. This allocation represents a trade-off between bandwidth allocated for HSDPA users, versus that for voice and non-HSDPA data users. The allocation is in units of channelisation codes for Spreading Factor 16, of which 16 exist and up to 15 can be allocated to HSDPA.
When the base station decides which users will receive data on the next frame, it also decides which channelisation codes will be used for each user. This information is sent to the user devices over one or more HSDPA "scheduling channels"; these channels are not part of the HSDPA allocation previously mentioned, but are allocated separately. Thus, for a given 2 ms frame, data may be sent to a number of users simultaneously, using different channelisation codes. The maximum number of users to receive data on a given 2 ms frame is determined by the number of allocated channelisation codes. By contrast, in CDMA2000 1xEV-DO, data is sent to only one user at a time.
Adaptive modulation and coding
The modulation scheme and coding is changed on a per-user basis depending on signal quality and cell usage. The initial scheme is Quadrature phase-shift keying (QPSK), but in good radio conditions 16QAM modulation almost doubles data throughput rates. With 5 Code allocation, QPSK typically offers up to 1.8 Mbit/s peak data rates, while 16QAM up to 3.6. Additional codes (e.g. 10, 15) can also be used to improve these data rates or extend the network capacity throughput significantly. Theoretically, HSDPA can give throughput up to 10.8 Mbit/s.
Other improvements
HSDPA is part of the UMTS standards since release 5, which also accompanies an improvement on the uplink providing a new bearer of 384 kbit/s. The previous maximum bearer was 128 kbit/s.
As well as improving data rates, HSDPA also reduces latency and so the round trip time for applications.
Along with the HS-DSCH channel, three new physical channels are also introduced: HS-SCCH, HS-DPCCH and HS-PDSCH. The High Speed-Shared Control Channel (HS-SCCH) informs the user that data will be sent on the HS-DSCH 2 slots ahead. The Uplink High Speed-Dedicated Physical Control Channel (HS-DPCCH) carries acknowledgment information and current channel quality indicator (CQI) of the user. This value is then used by the base station to calculate how much data to send to the user devices on the next transmission. The High Speed-Physical Downlink Shared Channel (HS-PDSCH) is the channel mapped to the above HS-DSCH transport channel that carries actual user data.
HSDPA UE categories
HSDPA comprises various versions with different data speeds.
:| Category | Max. number of
HS-DSCH codes | Modulation | Max. data rate
[Mbit/s] |
|---|
| 1 | 5 | QPSK and 16-QAM | 1.2 |
| 2 | 5 | QPSK and 16-QAM | 1.2 |
| 3 | 5 | QPSK and 16-QAM | 1.8 |
| 4 | 5 | QPSK and 16-QAM | 1.8 |
| 5 | 5 | QPSK and 16-QAM | 3.6 |
| 6 | 5 | QPSK and 16-QAM | 3.6 |
| 7 | 10 | QPSK and 16-QAM | 7.3 |
| 8 | 10 | QPSK and 16-QAM | 7.3 |
| 9 | 15 | QPSK and 16-QAM | 10.2 |
| 10 | 15 | QPSK and 16-QAM | 14.4 |
| 11 | 5 | QPSK only | 0.9 |
| 12 | 5 | QPSK only | 1.8 |
Roadmap
The first phase of HSDPA has been specified in the 3rd Generation Partnership Project (3GPP) release 5. Phase one introduces new basic functions and is aimed to achieve peak data rates of 14.4 Mbit/s (see above). Newly introduced are the High Speed Downlink Shared Channels (HS-DSCH), the adaptive modulation QPSK and 16QAM and the High Speed Medium Access protocol (MAC-hs) in base station.
The second phase of HSDPA is specified in the upcoming 3GPP release 7 and has been named HSPA Evolved. It can achieve data rates of up to 42 Mbit/s.[ It will introduce antenna array technologies such as beamforming and Multiple-input multiple-output communications (MIMO). Beam forming focuses the transmitted power of an antenna in a beam towards the user’s direction. MIMO uses multiple antennas at the sending and receiving side. Deployments are scheduled to begin in the second half of 2008.]
After HSDPA the roadmap leads to HSOPA, a technology under development for specification in 3GPP Release 8. This project is called the Long Term Evolution initiative. It aims to achieve data rates of up 200 Mbit/s for downlink and 100 Mbit/s for uplink using OFDMA modulation.
For details, see [HSPA mobile broadband today]
Adoption
: ''See also: List of Deployed HSDPA networks (not updated)''
As of May 25 2007, 102 HSDPA networks have commercially launched mobile broadband services in 55 countries. Nearly 40 HSDPA networks support 3.6 Mbit/s peak downlink data throughput. A growing number are delivering 7.2 Mbit/s peak data downlink, leveraging new higher-speed devices coming into the market. One network has been declared as “14.4 Mbit/s (peak) ready” and several others will have this capability by end 2007. The first commercial HSUPA uplink network is launched, with several more set to follow in 2007.
This protocol is a relatively simple upgrade where UMTS is already deployed.[.]
Code division multiple access-Evolution-Data Optimized (CDMA-EVDO) networks had the early lead on performance, and Japanese providers were highly successful benchmarks for it. But lately this seems to be changing in favour of HSDPA as an increasing number of providers worldwide are adopting it. In Australia, Telstra announced that its CDMA-EVDO network would be replaced with a HSDPA network. Rogers Wireless deployed HSDPA system 850/1900 in Canada on April 1, 2007.
So far, 171 device models from 47 suppliers have been launched, comprising: 53 handsets, 35 notebooks, 30 datacards, 19 wireless routers, 15 modems, 11 embedded module, 2 wireless modules, 1 wireless residential gateway, 1 media player, 1 camera, 1 GPS handset, 1 convergence platform & 1 baseband processor. For details, see www.gsmworld.com/HSPA.
Handsets
★ Motorola has released two HSDPA phones: the RIZR Z8 in May 2007 (a class 10 EDGE phone), and the RAZR² V9 in July 2007 (a class 12 EDGE phone).
★ Telstra and Samsung in late 2006 released the A501 and A701 Telstra Branded HSDPA mobile devices for Telstra's nextG network. These devices are capable of traditional mobile phone functions, web browsing, as a modem for another device and for viewing online video such as Foxtel on Mobile. Also the Z720 and U700 handsets
★ Sony Ericsson released the Z750, an HSDPA Quad-EDGE enabled phone in the first quarter of 2007. In June it also announced the K850i and W910i which is a category 6 device supporting up to 3.6 Mbit downlink speeds.
★ Palm, Inc. released the Treo 750, which does UMTS today and HSDPA via a firmware upgrade in 2007 for Cingular.
★ Nokia released its first HSDPA device, the N95, in late March 2007.[Nokia's N95 smartphone goes legit][It's what computers have become - the new Nokia N95 September 26, 2006] This is a category 6 device meaning up to 3.6 Mbit downlink speeds. Nokia E90, Nokia 6120 classic and Nokia 6110 Navigator are to be released with HSDPA.
★ Vodafone New Zealand and Vodafone Ireland recently released its HSDPA mobile broadband device the ''Vodem''. This device is designed for use with notebook or desktop computers and is in fact a re-badged Huawei Technologies E220 USB Modem.
★ Vodafone Australia currently sell re-badged HSDPA enabled Huawei Technologies E220 (USB) and E620 (PCMCIA) cards that provide downlink speeds of up to 3.6 Mbit/s. The network was initially rolled out only in Sydney and Melbourne CBDs but has recently been upgraded to include other metropolitan areas in Canberra, Perth, Adelaide, Brisbane, the Sunshine Coast and the Gold Coast.[[1]] Vodafone Australia's HSDPA network currently runs on top of the UMTS 2100 MHz network therefore making most HSDPA enabled handsets from Telstra and Vodafone/Optus unable to use the service (there are a number of exceptions to this rule; for example the Dopod 838Pro is a Quad-Band GSM (850/900/1800/1900 MHz), Tri-Band 3G/HSDPA (850/1900/2100 MHz) enabled handset.)
★ ZTE released its first HSDPA device in Australia, re-badged as the Telstra 252.
★ Motorola released three HSDPA handsets called ''RAZR maxx V6'', ''RAZR V3xx'', and ''KRZR K3''; and the Q 9h and MOTORIZR™ Z8 is expected to be available in Q2 of 2007 [2].
★ BenQ released its first HSDPA mobile phone, the EF91, in July 2006. But since BenQ-Siemens mobile filed for bankruptcy in Q3/2006, the future of BenQ mobile phones is unclear.
★ High Tech Computer Corporation released the TYTN handset/smartphone (branded as the MDA Vario II on T-Mobile, X01HT in Japan, Qtek 1605 on Vodafone, the SPV M3100 on Orange, the Dopod 838Pro and the I-Mate JasJam on Cellcom and Telstra NextG Network and the Cingular 8525 on Cingular) which supports HSDPA. Now the HTC P3600 / Trinity (Orange M700 or Dopod D810) is available and also supports HSDPA. The new HTC X7500/Advantage (T-Mobile Ameo, Dopod U1000) also supports HSDPA, currently limited by 1.8 Mbit/s downlink speeds by T-Mobile UK, although T-Mobile plans to upgrade its network yearly.
★ NEC released the N902iX High Speed along with NTT Docomo's HSDPA network launch on Aug 31 2006. It is the first handset capable of 3.6 Mbit/s to go into commercial service.
★ LG Electronics released the LG Chocolate (U830) in late 2006, supporting 3.6 Mbit/s HSDPA. The LG CU500 handset also supports HSDPA, up to 1.8 Mbit/s.
Notebooks
★ Fujitsu Siemens Computers was the second notebook supplier to integrate a UMTS Module in some of its notebooks. The Lifebook Q2010 supports not only data, it can also function as a telephone. The following notebooks from Fujitsu Siemens can be ordered with UMTS: LIFEBOOK P1610, T4215, E8210, AMILO Pro 3525, 3545 and AMILO Si 1848.
★ Acer integrate an HSDPA module in some laptops.
★ Dell began releasing, in December 2005, laptops with in-built HSDPA chips from Vodafone, enabling the laptops to be continuously connected to the internet via Vodafone's 3.5G network in the UK and several other countries. The Dell laptop models currently with this capability are the Latitude D420, D430, D620, D630, D631, D820, D830, D831, and XPS M1210, M1330, M1770, M2010, M4300 and M6300 models.[Dell (UK)] As mentioned above, the D620, D820, and XPS M1210 models are also sold in the United States with HSDPA service from AT&T Wireless.
★ High Tech Computer Corporation - HTC P3600, HTC Advantage X7500, HTC Shift (Ultra-Mobile PC).
★ HP UK announced that it will begin integrating Vodafone's 3.5G HSDPA technology into its laptops[zdnet news]
★ Intel was to integrate HSDPA wireless technology (supplied by Nokia) into its next generation of Centrino chipset for laptops known as Santa Rosa, but this was scrapped when both Nokia and Intel decided there was not enough of a business case.[Forbes] The new chipset was due to be available in laptops world wide in the first half of 2007[news.com] and would have therefore eliminated the need for laptop owners to buy separate HSDPA cards as the technology would have already been integrated in the laptop.
★ Lenovo has been shipping Vodafone's high speed HSDPA mobile data connectivity technology in various models of their Lenovo and IBM branded ThinkPad notebooks since mid-2006.[ThinkPad notebooks IBM]
★ Panasonic supports EDGE and embedded HSDPA integrated inside several of their Toughbook models.
★ Option sells HSDPA enabled PCMCIA data cards. It also offers embedded wireless modules to laptop manufacturers.
★ Flybook[Flybook] released their V33i model with HSDPA in October 2006; and V5 and VM with HSDPA module in second half of 2007.
Cellular routers
★ Cellular router
★ WAAV, Inc. manufactures EVDO and HSDPA routers. WAAV's AirBox X2 can connect to both networks at once.
Marketing as Mobile Broadband
During 2007, an increasing number of telcos worldwide began selling HSDPA USB Modems as mobile broadband connections. In addition, the popularity of HSDPA landline replacement boxes grew - providing HSDPA for data via Ethernet and WiFi, and ports for connecting traditional landline telephones. Marketed with connection speeds of "up to 3.6Mbs", which is only attained under ideal conditions. As a result these services can be slower than expected, especially when in fringe coverage indoors.
See also
★ 3GPP
★ 3GPP Long Term Evolution
★ Cellular router
★ Evolved HSPA
★ High-Speed Uplink Packet Access
★ High-Speed OFDM Packet Access
★ List of device bandwidths
★ Mobile Internet access worldwide
★ Quad band
★ Tri band
★ UMTS
★ UMTS frequency bands
References
★ Martin Sauter: ''Communication Systems for the Mobile Information Society'', John Wiley, September 2006, ISBN 0-470-02676-6
External links
★ Official HSPA Website
★ Broadcom: First HSDPA 'Smartphone-on-a-Chip'
★ Understand HSDPA's implementation challenges
★ Deployment List
★ Qualcomm: HSDPA for Improved Downlink Data Transfer White Paper
★ HSDPA Test Solutions from Anritsu
★ List of HSDPA compatible cell phones
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