Difference (if any) between EV-DO and HSDPA

[gator]

I don't know much about these new standards for broadband wireless WAN - what are the salient features EVDO and HSDPA? First, are these same/similar or completely different technologies? How do these compare to todays WLAN a/b/g/n speeds? I know they are lower, but are these seeing more development? Do you think they will become mainstream someday and replace wireless a/b/g/n/whatever?

I did see the wikipedia sections about these two technologies, but I was unable to find east-to-understand information. I am sure that with digging for data I'll eventually get somewhere to understand what I am asking for, but can someone here who knows about these post some answers (or some links where I can read further)?

Mods, if this is not in the correct discussin area, please move it to the right location.

[tvsjr]

Totally different technologies.

802.11a/b/g/n are short-range (~500ft.) technologies operating at either 2.4GHz or 5.8GHz to provide high data rate (11, 54, 200Mbps) connections to local users.

EVDO and HSDPA are 3G mobile technologies designed for wide-range wireless deployment. Other competitors include 802.16 WiMAX. These technologies provide a few megabits of coverage (EVDO Rev B provides a theoretical 4.9Mbps max... HSDPA provides 14.4Mbps max... but, at this point, no US carrier has big enough pipes installed to their sites to provide such bandwidth) over a wider coverage area.

EVDO/HSDPA/WiMAX will likely not replace 802.11a/b/g/n, as they are complimentary technologies, not competing. Similarly, 802.11 hasn't replaced Bluetooth, even though both provide similar data rates (though Bluetooth's range is significantly more limited).

If you're considering purchasing a WWAN solution (card or built-in), you need to consider what provider you're going with. Sprint, Verizon, and Alltel are building out EVDO... Cingular is the HSDPA/UMTS carrier. However, HSDPA is more common worldwide.

[GomJabbar]

Currently both Verizon and Sprint support EVDO. Currently Cingular supports HSDPA. They are roughly equivalent speed-wise. EVDO currently has more coverage area. Cingular also uses EDGE which does cover a broad area, but it is slow compared to HSDPA.. T-Mobile only supports EDGE at this time. Pricing is simular. Verizon has been reported putting a 5 GB cap on their "unlimited" plan. They have terminated users that go over this cap. This was last summer. I have not heard if their policy has changed or not.

[bill bolton]

Difference (if any) between EV-DO and HSDPA

HSDPA has the ability to go to much higher channel bandwidths than EVDO. The Telstra national NextG 850 MHz HSDPA network in Australia is currently running 7.2 Mbps and will be offering 14.4 Mpbs by mid year.

The biggest operational difference is that there can be multiple lower bandwidth channels in an HSDPA cell, plus access to those channels can be time sliced on a much more deterministic basis than EVDO access, so allowing much better sharing of available cell bandwidth.

Projections are for 3G HSDPA capacity to increase significantly with newer technologies for 3G starting to emerge now.

There is also WiMax technology (sometimes claimed to be 4G) which is still in the emerging stage. There are some very interesting claims being made for it but there are not large scale commercial deployments as yet, so its still somewhat pie in the sky.

[tomh009]

If you're considering purchasing a WWAN solution (card or built-in), you need to consider what provider you're going with. Sprint, Verizon, and Alltel are building out EVDO... Cingular is the HSDPA/UMTS carrier. However, HSDPA is more common worldwide.

This is indeed the key point; EV-DO is available with CDMA operators, primarily in US and Canada (Sprint, Verizon, Bell, Telus). If this is your preferred operator, EV-DO is probably what you should go with. Peak speeds with EV-DO are in in the 3 Mb/s range, but more typical real-world speeds are probably on either side of 500 Kb/s. Note that some CDMA operators will only have support for the older 1xRTT technology, which peaks out at 144 Kb/s, and realistically provides roughly similar performance to a conventional analog modem.

HSDPA is the path for the GSM operators (AT&T/Cingular, T-Mobile, Rogers in US & Canada) and this is the dominant technology worldwide. As GomJabbar noted, not all GSM operators have HSDPA support; depending on the country you may get only EDGE or GPRS. For example, T-Mobile USA does not have HSDPA yet (though they have announced deployments starting in mid-2007), only EDGE. EDGE theoretically maxes out at 384 Kb/s but practical speeds are probably around 100-200 Kb/s, while the older GPRS standard (as often used by devices such as Blackberries) is designed to provide 80 Kb/s but in the real world will be well slower than an analog modem.

All that said ... if you want WWAN access, and would like to stay with the same company you already use, there is your first choice. If not, check the data plans and geographical coverage with other providers to identify your best choice.

If you do a lot of international travel, a HSDPA/UMTS modem is probably your best choice as this is well supported in Europe, North America, Asia Pacific and South Africa. A note of caution is to verify the WWAN card's frequency band support as much of the world uses 1900/2100 MHz while some of the North American operators use different frequences due to spectrum inavailability in the 1900 and 2100 MHz bands.

[gator]

Fantastic info guys. Many thanks to all who replied here, esp tomh009 - I was looking for something just like this.

I don't plan to get any of these, just was curious to learn about new technology. One of you guys should post this in the wikipedia ... with all the crazy acronyms coming out today, it is sometimes difficult to know the basic differences (like what tomh009 posted i.e. EV-DO is for CDMA, HSDPA is for GSM). I am a recent electrical engineering graduate (and doing a PhD now, related to VLSI/Devices) and an avid follower of technical stuff; still I found it a bit difficult to find a reference for this topic.

Thanks once again - if someone knows anything in more detail, please do post here.

[tomh009]

You can find some more info in the Wikipedia:
http://en.wikipedia.org/wiki/Comparison ... _standards

Some good info there, though that entry doesn't really talk as much about the practical tie-in between the voice (GSM, CDMA) and data technologies. But if you spend a few hours surfing the links from that page I expect you will know a lot more than I do in the end.