Embedded HSDPA

Other Unique Engineering Ideas

HSDPA brings high-speed downlink data capabilities to WCDMA (UMTS) networks and allows wireless users to stream high-quality video and audio, quickly browse graphics-heavy websites, and run other advanced applications on mobile handsets. HSDPA is an evolution of existing WCDMA networks that provides a powerful boost in data rates and an increase in overall network capacity.

1. Description

2. Why

3. How

4. Future Trends

5. Related Links

 Useful Links WCDMA (UMTS)

Description

HSDPA the acronym stands for High-Speed Downlink Packet Access. Essentially, it is an upgrade to existing 3G networks that were originally built out in Europe based on the UMTS (Universal Mobile Telecommunications System) standard.HSDPA also significantly reduces network latency, the delay associated with response to network requests, which further boosts the performance of "chatty" applications such as Web browsing over HTTP. Together with better in-building coverage and improved quality of service management, the end result should be a dramatically enhanced user experience, and a network that is able to tolerate high network loads at busy times much more effectively.

Why

Internet connectivity is a mixed blessing for the users indeed its much inconvenient because of these reasons:

  • Having to search for Wi-Fi hotspots and/or LAN ports when you only have ten precious minutes before rushing to your next meeting.

  • Need for having cables

  • Additional drivers or

  • Portable modems sticking out of your notebook PCs and adding to your burden

3G networks upgraded to HSDPA are anticipated to deliver three to four times the data capacity and three to four times the data access rates of UMTS. Further imagine wireless connection on a stylishly- and intelligently-designed notebook PC anytime and anywhere you may need. All you need to do is to subscribe to the service provided by your local Telco and slot in a SIM card into the notebook PC. This is as close as anyone can possibly and realistically get to the widely hyped adage of true mobile freedom.

How

The modules installed by Dell will support UMTS and GPRS (2.5G) as well as HSDPA. They may therefore be used to connect via the commonly available cellular data standards today, while being ready to take advantage of HSDPA as coverage increases to useful levels, as it undoubtedly will during the lifetime of a new PC bought this year. In physical terms, the UMTS/HSDPA module will be fitted internally with the antenna integrated into the notebook lid, and will generally co-exist alongside a WiFi module.

  • Each user device periodically transmits an indication of the downlink signal quality, as often as 500 times per second.

  • 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.

  • 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 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 16 QAM modulation almost doubles data throughput rates. HSDPA can give throughput up to 14.4 Mbit/s.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.

Future Trends

HSDPA rollout is set to gain momentum as we go through the second half of the year, though timescales vary between operators and indications are that it will take some time before 3G networks are fully upgraded. From that point onwards, new cell sites commissioned as the physical 3G networks continue to expand will be HSDPA enabled. In terms of HSDPA coverage, we can expect the kind of rollout schedule we have seen before with 3G - specific cities and major conurbations first, with wider coverage following.The first phase of HSDPA has been specified in the 3rd Generation Partnership Project (3GPP) release. 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.

Keywords

High-Speed Downlink Packet Access, Cellular router, High-Speed OFDM Packet Access, 3GPP Long Term Evolution.

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