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High-Speed Downlink Packet Access

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High-Speed Downlink Packet Access (HSDPA) is a mobile telephony protocol, also referred to as 3.5G (or 3½G) technology, which provides a smooth evolutionary path for UMTS-based 3G networks allowing for higher data transfer speeds, up to 14.4 Mbit/s per cell in the downlink and 2 Mbit/s per cell in the uplink.

An evolution of the W-CDMA standard, HSDPA achieves the increase in the data transfer speeds by defining a new W-CDMA channel: a high-speed downlink shared channel (HS-DSCH) that operates in a different way from existing W-CDMA channels and is used for downlink communications to the mobile.

Technology

The HS-DSCH channel does away with two basic features of other WCDMA channels - the variable spreading factor and fast power control - and instead uses

  1. Adaptive Modulation and Coding (AMC),
  2. fast packet scheduling at the Node B (Base Station) and
  3. fast retransmissions from Node B (known as HARQ-Hybrid Automatic Repeat Request)

to deliver the improved downlink performance. The concept of "incremental redundancy" is used in HARQ, where retransmissions contain different codings of the user data, relative to the original transmission. When a corrupted packet is received, the user device saves it, and combines it with subsequent retransmissions, to formulate an error-free packet as quickly and efficiently as possible. Even if the retransmitted packet(s) is itself corrupted, the combination of the sum of the errored transmissions can yield an error-free packet.

Fast Packet Scheduling

The HS-DSCH downlink channel is shared between users using channel-dependent scheduling to take advantage of favourable channel conditions to make best use of available radio conditions. Each user device periodically transmits (as many as 500 times per second) an indication of the downlink signal quality. The Node B uses this information received from all user devices to decide which users will be sent data on the next 2 ms frame and, for each user, how much data should be attempted. 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 tradeoff 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 of which up to 15 can be allocated to HSDPA.

When the Node B decides which users will receive data on the next 2 ms frame, it also determines which channelisation code(s) will be employed for each user, and this information is sent to the user devices over one or more HSDPA "scheduling channels" (these scheduling 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 code. The maximum number of users to receive data on a given 2 ms frame is determined by the number of allocated channelisation codes. This differs from CDMA2000 1xEV-DO, where 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.

QPSK is the initial modulation scheme, however, in good radio conditions the introduction of 16QAM modulation will improve data throughput rates by approximately double that of QPSK. QPSK with 5 Code allocation will typically offer up to 1.8 Mbit/s peak data rates. 16QAM with 5 Codes will increase this to 3.6 Mbit/s. 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 release 5 UMTS networks, which also accompanies an improvement on the uplink providing a new bearer of 384 kbit/s (previous max bearer was 128 kbit/s).

As well as improved data rates that are associated with HSDPA one of the key benefits that are seen is the reduction on latency, improving the round trip time for applications.

Along with the HS-DSCH channel, two new physical channels are also introduced. One is Signaling Control Channel which informs the user that the data to be sent on HS-DSCH 2 slot ahead. The second one is a reverse channel, terminating at the Node B, which carries acknowledgement information and current channel quality of the user.

Roadmap

The First phase of HSDPA has been specified in 3GPP release 5. Phase one introduces new basic functions and is aimed to achieve peak data rates of 14.4 Mbps. 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 the Node-B.

The Second phase of HSDPA is currently being specified in 3GPP release 6 and is aimed to achieve data rates of up to 28.8 Mbps. It will introduce antenna array technologies such as beamforming and Multiple Input Multiple Output (MIMO). Beam forming can be described as focusing the transmitted power of an antenna in a beam towards the user’s direction. Knowing that the limiting resources are the transmission power of the base station sector, one can understand that beam forming is a means of increasing this power. MIMO uses multiple antennas at the sending and receiving side.

The Third phase of HSDPA which still is a long way down the road will concentrate on the air interface. It will introduce a new Air Interface with Orthogonal Frequency Division Multiple Access (OFDMA) and higher modulation schemes. Phase three of HSDPA aims at data rates of up to 50 Mbps or more.

Adoption

Although 3G is not available in most countries, this protocol does have a chance to become the follow up to 3G where WCDMA is deployed. Its success as a GSM-replacement, vis-à-vis other contenders like CDMA2000 1x or CDMA2000 1xEV-DO and cellular datacommunication standards like WiMAX (IEEE 802.16) is still unclear, especially considering that SK Telecom and KTF's CDMA2000 and CDMA2000 1xEV-DO is considered as successful introduction in South Korea and KDDI's CDMA2000 is generally considered as being much more successful and smooth than DoCoMo's and ex-Vodafone's (now: SoftBank's) UMTS/W-CDMA introduction in Japan, which are much slower than initially hoped, the Japanese networks are being upgraded with HSDPA technology though which gets them back into direct competition with CDMA2000, which also does not support video calling (as WCDMA does).

Lately the situations seems to be changing in favour of WCDMA as more and more providers worldwide are adopting it. KTF and SK Telecom are building a nationwide WCDMA network, with SK Telecom announcing that by first half of 2007 it will be selling SBSM (Single Band Single Mode) WCDMA handsets to its customers and that it will be cutting funding to its CDMA2000 network in favour of its newly deployed WCDMA network. It seems that the CDMA2000 networks in Korea are not going to be further developed after the networks have chosen the WCDMA technology.

Current Deployment

Australia:

  • Telstra announced plans on 15 November 2005 for the rollout of a new national 3G/WCDMA network with HSDPA which is expected to be operational by the end of 2006. In 2007 it is expected to reach 98% of the Australian population.
  • Vodafone Australia began trials in Sydney on 6 September 2006 and announced plans to roll out the network nationally in 2007.
  • Hutchison plans to roll out a 3.6mbps HSDPA network by March 2007.

Austria:

Bahrain

  • MTC-Vodafone introduced 3.5G in Bahrain in May 2006 as a trial service in a small area only (in Seef District) and announced that they are planning to make Bahrain the first country with 100% 3.5G coverage in the world. This is because Bahrain is a small country and doesn't need many upgrades since it already has 100% 3G coverage.

Belgium

Bulgaria

  • M-tel introduced HSDPA on March 6, 2006 with full coverage in the capital city Sofia and plans to cover other major cities by the end of the year.
  • Globul launched HSDPA on September 25, 2006 with full coverage in the capital city Sofia and 3 of the other major cities.

Canada:

Croatia:

Czech Republic:

Estonia:

  • Telecom operator EMT launched (24 April, 2006) second HSDPA network in the Nordic Countries and first in Estonia. The solution is provided by Ericsson, service is provided soon in whole EMT 3G network.

Finland:

  • Telecom operator Elisa Oyj launched (6 April, 2006) the first commercial HSDPA network in the Nordic Countries. The solution, provided by Nokia, is implemented in the whole of Elisa's 3G network in Finland and Estonia.

France:

Germany:

Greece:

Hong Kong:

  • SmarTone-Vodafone officially launches Hong Kong's first commercial HSDPA service on June 6, 2006. SmarTone-Vodafone’s HSDPA network provides a data speed of 3.6Mbps and flat-rate internet access services about 63 US Dollars.
  • CSL officially launched HSDPA service on September 19, 2006, together with Dopod 838pro, the first HSDPA compatible PDA based on Windows Mobile 5.0.

Hungary:

Iceland:

  • Novator will start deploying HSDPA trial in Iceland late 2006, according to the HSDPA convergence press release from Industria.

India:

  • The 3G spectrum will be available for commercial in India very soon. It is also expected to see the deployment of 3G in near future.

Ireland:

  • Vodafone will start deploying HSDPA in Dublin in October 2006 - two thirds of the country's population will have access to the HSDPA network by October 2007, according to Vodafone Ireland.
  • O2 will offer 3.5G using HSDPA nationwide beginning September 2006 with over 60% coverage by the end of 2006 and 80% by end of 2007, according to O2 Ireland.

Israel:

  • Partner has announced (March 8, 2006) deployment of 3.5G, and will offer phones and computers with built-in HSDPA capability.

Italy:

  • 3 launched nationwide HSDPA service (25 main cities) in March 2006, Vodafone (all the UMTS network, about 70% of population, converted to HSDPA) in June 2006, TIM (main cities) in July 2006 and WIND is expected in 2006.

Japan:

  • KDDI has been commercially deploying 3.5G services based on a nationwide 1xEV-DO network since June 2006.
  • DoCoMo has recently announced (2005) that it will introduce HSDPA from 2006. They will introduce Super 3G, an advanced version of HSDPA and HSUPA in 2009 [1].

Lithuania:

  • BITE has been commercially deploying 3.5G services based on a nationwide network since June 2006.

Malaysia:

  • MAXIS Communications Bhd (www.maxis.com.my) announced in April 2006 that it has fully integrated HSDPA into its 3G network and anticipates HSDPA services by September 2006. Maxis officially launches its HSDPA services on 26 September 2006, delivering broadband Internet access to residential customers in Kuala Lumpur. The service is delivered through a specially designed low-cost HSDPA modem, a world's first.
  • Celcom(Malaysia) Bhd (www.celcom.com.my) has integrated 3.5G into its current 3G network, and plans to fully cover peninsular malaysia with 3.5 G by the end of year 2007.

Netherlands:

  • T-Mobile has launched the HSDPA service half April 2006, covering 50% of the Dutch population.
  • Vodafone launched its HSDPA service October 2006, for now also only covering roughly 50% of the Dutch population.

New Zealand:

  • Vodafone launched a national 3G/WCDMA network in mid-2005. This was followed by a network upgrade to HSDPA which was launched on 12 September 2006. The HSDPA network however currently covers less than 40% of the population. Coverage of the original GMS/GPRS network covers some 96% of NZ's population.

Philippines:

  • Globe Telecom used its 3G and HSDPA facilities during the 23rd SEA Games in 2005. It is also the first telecom company in Asia-Pacific to commercially deploy HSDPA service and is among the first 20 worldwide on April 30, 2006.
  • Smart Communications is the first-HSDPA ready network in the country. It launched its commercial HSDPA-enabled 3G network on the 1st of May, 2006.

Portugal:

  • 3.5G has been available since 5 April 2006 on all three mobile Operators: TMN, Vodafone and Optimus.
  • The coverage is sometimes on main cities at speeds up to 3.6 Mbit/s, generally 1.8Mbit/s in most cities. Most of the Portuguese territory has only UMTS coverage, HSDPA is being used as a marketing strategy than real service upgrade.

Saudi Arabia:

  • AlJawal has announced that it will introduce its 3.5 G service by the summer 2006.
  • Mobily also announced that it will introduce its 3.5 G service by the summer 2006.

Singapore:

  • MobileOne has signed an agreement with Nokia for it to supply the first HSDPA network in Singapore. The network is expected to be ready in the fourth quarter of year 2006.

Slovakia:

  • Orange has launched HSDPA @ 3,6Mbps from UMTS at August 23, 2006. Only in this network all over the world is allowed to use HSDPA wherever is UMTS coverage. HSDPA Roaming is too allowed, but is expensive to use it, because 1MB full duplex data transfer abroad costs more than €10.
  • T-Mobile launched HSDPA at August 22, 2006 only in some city quarters of Bratislava.

Slovenia:

  • Mobitel has commercially launched HSDPA in October 2006 with speeds up to 3,6Mbps.

South Korea:

  • SK Telecom and KTF have been commercially deploying 3.5G services based on a nationwide 1xEV-DO network since later 2002.
  • SK Telecom launched commercial HSDPA service for phone by May 15, 2006 in 25 cities of South Korea, which expecting to be up to all 84 cities by end of year 2006, and it's the world first HSDPA service that using USIM card for mobile phone device, Samsung's SCH-W200 which support DBDM(Dual Band Dual Mode) that covers 2G,3G and 3.5G service.
  • KTF launched commercial HSDPA service for phone by June 30, 2006 in 40 cities of South Korea, which expecting to be up to all 84 cities by end of year 2006.

South Africa:

  • Both MTN and Vodacom, two of South Africa's leading GSM operators have already announced their deployment of the fast HSDPA service delivering theoretical downlink speeds of 1.8 Mbit/s after introducing UMTS 3G services more than 14 months ago. Vodacom was the first to deploy HSDPA commercially in South Africa becoming the 14th network world-wide to deploy HSDPA which created some kind of a battle between the two networks who have become renowned for their fierce competition in the mobile broadband space to be the first to launch new and innovative technologies and services.

Spain:

  • Amena (Orange) become the first spanish operator to offer HSDPA service in Spain. Starting in Madrid, Barcelona, Zaragoza, Burgos and Pamplona on 19 June 2006 (29% population). Starts offering 1.8 Mbit/s service. By November 2006 they want to have 41% population covered and 3.6 Mbit/s.
  • Movistar and Amena started tests at Barcelona in coincidence of the 3GSM World Congress, February 2006.
  • Movistar started to test HSDPA Service in April 2006.
  • Vodafone has started tests in the city of Salamanca in March, 2006.

Vodafone Spain is launching HSDPA in the following cities this week: Madrid, Barcelona, Seville, Valencia, Bilbao, Zaragoza, Málaga and Albacete. Link to news item (in Spanish): [2]

Sweden:

  • 3 will introduce HSDPA service in spring 2006.

Denmark:

  • 3 will start deploying HSDPA service in the biggest cities, in fall 2006.

Switzerland:

United Kingdom:

  • Vodafone has launched HSDPA services during the summer of 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.
  • 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.
  • 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 (peak) 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 released (on 9 May 2006) a quad band HSDPA data card for notebook computers to wirelessly access the internet through T-Mobile's HSDPA network. However, T-Mobile has come under intense criticism from potential customers due to their policy to ban the use of VoIP applications such as skype with the data card (a policy many believe is made to protect the revenues from their mobile phone business, although T-Mobile says it is because VoIP is not quality assured and might impact other network users).
  • 3 UK has announced they will begin HSDPA services in the second half of 2006.
  • Dell began releasing, in June 2006, 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, D620 and D820 models (see [3]).
  • BenQ will release its first HSDPA mobile phone, the EF91, in July 2006.
  • HTC have announced an HSDPA device running Windows Mobile 5.0 on 7 Sep 2006, which will ship as the P3600.
  • Motorola has announced 2 HSDPA handsets called the RAZR MAXX and RAZR XX, which are scheduled for release in Q4 2006 [4].
  • HP UK has announced that they will begin integrating Vodafone's 3.5G HSDPA technology into their laptops [5]
  • Lenovo has announced that they will begin to integrate Vodafone's high speed HSDPA mobile data connectivity technology into upcoming models of ThinkPad notebooks [6]

United States:

  • Cingular is operating a 3G/HSDPA network, called BroadbandConnect, currently in 16 U.S. markets covering 52 cities and is expected to be online in most major markets in the U.S. by the end of 2006. In the U.S., it provides average download speeds between 400-700 kilobits per second (kbit/s), with bursts to more than one megabit per second (Mbit/s).
  • Cingular faces competitive pressure from operators such as Verizon Wireless and Sprint who use a competing 3G technology, 1xEV-DO, and who have already deployed a similar high speed data service.
  • In April 2006, Dell released two notebooks, the Latitude D620 and D820, with onboard HSDPA wireless data capabilities from Cingular, enabling it to connect to Cingular's BroadbandConnect 3G/HSDPA service.

HSDPA Cellular Routers

  • Junxion, Inc. offers two flexible commercial-grade cellular routers (one with Wi-Fi LAN, one without)for large and/or sophisticated enterprise and government deployments. The two Junxion Box models use field-upgradeable PC Card modems, and always support the latest cellular network technologies through automated remote firmware updates(eg. drivers supported Cingular HSDPA modems prior to network launch, will support HSUPA). Junxion's cellular routers are the first in this category to be certified and promoted by two of the top three US wireless carriers: Cingular (learn more)and Sprint (learn more)for a wide range of applications, including: landline replacement, landline back-up, M2M/telemetry, mobile/vehicle, portable networks, remote security, and public/private transit. Large-scale and small deployments utilize Junxion's hosted Field Commanderremote management tool, which was co-developed with Cingular/Sprint personnel and enterprise customers.

See also

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