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What is HSDPA?

Frank Sliden
Frank Sliden

HSDPA, short for High-Speed Downlink Packet Access, is a new protocol for mobile telephone data transmission. It is known as a 3.5G (G stands for generation) technology. Essentially, the standard will provide download speeds on a mobile phone equivalent to an ADSL (Asymmetric Digital Subscriber Line) line in a home, removing any limitations placed on the use of your phone by a slow connection. It is an evolution and improvement on W-CDMA, or Wideband Code Division Multiple Access, a 3G protocol. This protocol improves the data transfer rate by a factor of at least five over W-CDMA. HSDPA can achieve theoretical data transmission speeds of 8-10 Mbps (megabits per second). Though any data can be transmitted, applications with high data demands such as video and streaming music are the focus of HSDPA.

HSDPA improves on W-CDMA by using different techniques for modulation and coding. It creates a new channel within W-CDMA called HS-DSCH, or high-speed downlink shared channel. That channel performs differently than other channels and allows for faster downlink speeds. It is important to note that the channel is only used for downlink. That means that data is sent from the source to the phone. It isn't possible to send data from the phone to a source using HSDPA. The channel is shared between all users which lets the radio signals to be used most effectively for the fastest downloads.

A HSDPA modem and USB cord.
A HSDPA modem and USB cord.

The widespread availability of this protocol may take a while to be realized, or it may never be achieved. Most countries did not have a widespread 3G network in place as of the end of 2005. Many mobile telecommunications providers are working quickly to deploy 3G networks which can be upgraded to 3.5G when the market demand exists. Other providers tested HSDPA through 2005 and are rolling out the service in mid to late 2006. Early deployments of the service will be at speeds much lower than the theoretically possible rates. Early service will be at 1.8 Mbps, with upgrades to 3.6Mbps as devices are made available that can handle that increased speed.

HSDPA provides mobile devices with download speeds similar to those from an in-home connection.
HSDPA provides mobile devices with download speeds similar to those from an in-home connection.

The long-term acceptance and success of the protocol is unclear, because it is not the only alternative for high speed data transmission. Standards like CDMA2000 1xEV-DO and WiMax are other potential high speed standards. Since HSDPA is an extension of W-CDMA, it is unlikely to succeed in locations where W-CDMA has not been deployed. Therefore, the eventual success of the protocol as a 3.5G standard will first depend upon the success of W-CDMA as a 3G standard.

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Discussion Comments


In answer to the Nokia C3-01 query. I had same problem. If you put the network mode into GSM rather than dual mode then it should stop going into 3,5G. I had similar problem to you in that I couldn't make calls from abroad tho could receive calls and send sms - weird!


My phone keeps switching to 3.5G (HSDPA) network. It's a basic phone Nolia C3-01 and all I use it for is calls and text. But when it switches, I can't take calls (I can hear them they can't hear me, or it goes straight to voicemail even though I have signal bars showing). How can I stop this. I just want an ordinary O2 signal.


Can I use a CDMA sim card in a wcdma Dongle of D Link DWM-156?


i was using x10 but I can't use 3g properly and i can't access live tv.


How does the speed and quality of service of HSDPA compare to WiFi enabled phones such as the Nokia E65?


I am using huwaie e1750 7.2 usb modem of o2. i have been using this for the last two months and was getting the speed 400kb/sec on bsnl 2g but for 15 days just getting the speed of 40-45 kbps only.

Please help me. What is happening? I get the full network access of hsdpa, but the speed is just 45/kbps. help me.


Please help i upgraded my 3G card to HP 620 with microsoft office 7 installed, and when starting use it, it needs a product key. where can i get those keys because it was installed already? it has keys as it is a product or a software.


i have a dell laptop. in my laptop, a sim card feature is available but it requires an HSDPA sim card. how can i use my laptop with a sim card?


I received an upgrade via 3 for my dongle. I downloaded the software! since then it's almost impossible to download, avoid this upgrade if your original dongle software had previously a good signal strength. I contacted 3 and was told it will get better in the coming months.


Will a HSPA phone be able to function on a CDMA network?


Does this mean HSDPA is free internet for phones?


what are the technologies in 3g?


I am confused whether HSDPA and wifi will function the same? will i be able to connect to the internet with HSDPA if i have the router and will be able to surf the net, especially with the phone 6600i slide?


i wonder whether an HSDPA phone like the N95 with HSDPA + GSM (dual sim) can run on the Reliance network (CDMA) in India.


I'm tied into a 24 month Contract with 3 Mobile, and supposedly receive broadband speeds through a "dongle". At the best of times, speeds are mediocre, and when I'm informed that I'm getting HSPDA it's so slow as to make it not worth bothering! HSPDA from 3 is garbage. Don't go near it!


If there is an H or 3.5G or 3G+ showing at the top, then you have HSDPA, or mobile phone broadband reception, meaning your mobile internet will run really fast.


I reckon it will be 2012 before HSDPA covers the whole of Britain. Most areas only have 2.5G (Fast GSM), and some have only 2G (Ordinary GSM) and that is pitifully slow, much slower than even dial-up on a PC.


My phone - a Sony Ericsson V640i has HSDPA and it's top speed appears to be about 1.4Mbps, which is about 4x the standard 3G speed of about 0.36Mbps. That means it can download a 3MB music track in under 30 seconds. 3G takes over a minute and 2.5G seems to take forever. But Vodafone HSDPA on a laptop is about 5 times faster than on mobile phone. And it is also faster than home broadband, certainly where I live, 3 miles from Norwich City Centre.


When will the UK have complete HSDPA coverage?


Can HSDPA have a negative effect on your body?


What is the latest internet connection today?


I have a sony ericson T700 and part of its use is internet connection -- used as a modem so I can connect my laptop to the net.

I used to live in a bustling city where 3G and HSDPA are readily available. My internet connection works fine especially in the wee hours of the morning. I'm now in a remote place and GPRS is more available with occasional popping of "3G" and "H" symbols. The internet still works, my phone suite shows I am receiving up to 9.3MB, but it's slower now.

Just consult your cellular service provider if they support such before buying.


Yes the 5800 does have HSDPA google gsm arena


hi. does the new nokia 5800 have HSDPA?


I don't know squat about mobile phones, and I just bought a Sony Ericsson W980. There is an H on the top left corner of the display when the phone's in standby, and I read somewhere that it means HSDPA. Now, can anyone tell me, when this H is visible on the display, does that mean that my phone is connecting to the Internet, or what does it mean?


hi guys,

A lot of you asked the question whether HSDPA will be faster internet than Nokia E65 or Nokia N95 and so on. HSDPA is a network and the Nokia products are phones that use a network. HSDPA will be faster than any "mobile" internet on your phone (by "mobile", i mean anything but wi-fi).

You should be worried about whether your device will support HSDPA, not if HSDPA is faster internet than your phone...a phone is not internet :-). cheers...btw, N95 is a great phone.


I have a Raon Everun ultra mobile PC, which has a SIM card would the HSDPA work for this device, if I put the card in?


How does the speed and quality of service of HSDPA compare to WiFi enabled phones such as the Nokia E65?


What company or private entity created HSDPA technology?


zamano ? -- what do you think


Hi, subject to Indian service providers like Airtel, will they be able to provide a faster download speed if I buy a HSDPA enabled phone like nokia N95? Will the surfing be of higher speed as compared to surfing using the Nokia N72 or N70?


How does the speed and quality of service of HSDPA compare to WiFi enabled phones such as the Nokia E65?

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