LTE, HSDPA, DC-HSDPA: Explain this alphbet soup of “4G” to me

Note : with the release of the new iPhone 5, this post has gotten a lot of attention again. Pretty much all the concepts in this are good still. So if your looking for an explanation of that all this abc terms are, then it’s still good. Some of the specific facts, however aren’t true any more (network speeds change as more people are on it, there is a world band LTE chip now, etc.)

With the iPad (sorry, “the new iPad”) coming out this Friday, there’s a lot of talk if people have 4G in their area. But with LTE, LTE Advanced, HSDPA, HSPA+, DC-HSDPA… It’s easy to get confused as to what is and is not faster, what carriers support what technologies, and if these labels even mean anything to anyone. The big announcement is that the new iPad supports LTE and for many that means Internet that’s faster than what they get over their home’s land Internet lines. But what does all this “4G” actually mean anyway?

To start out, there is technically no such thing as “4G” in the United States. That’s why I keep using quotes when talking about it. 4G refers to the fourth generation of phone data service, a digital standard with a peak speed above 1Gbps (Gigabit per second) download according to the ITU-R organization (international data group). While LTE Advance does support this, no carriers actually use it. LTE that everyone is using refers to as “4G” is technically classified as 3.9G and is the required stepping stone to get to the mythical 4G networks.

So that’s all well and good, but does that mean anything to the average user? No. And nor should it really. All your average consumer will want to know is: “Is this faster than what I have now?” and that answer is going to be yes. So for all the market speak… “4G = Faster than 3G”. In fact not only is LTE faster than what people currently are using on their phones, but in some situations faster than they are using in their own homes.

Just a warning…. some of the stuff is a bit geeky but you can just skim it and pay attention to the charts I made. They tell the overall story pretty well, if you don’t’ care about the details. Peak speeds refer to what the network is marketed as, but users rarely get. Real world speeds are typically the fastest a user will get, and therefore what you’d probably want to measure the networks really on.

The common 3G standards and home use
To understand what these new “4G” networks offer in terms of speed, first its a good idea to figure out what people currently have. Also since the iPad supports all current 3G, and not everywhere has LTE service it’s a good idea to get a grasp on what 3G networks and your own home internet allows for.

2G is the first real use of data in cell use. Unfortunately this isn’t a 3G standard, and isn’t supported by the new iPad. But for educational reasons here’s the baseline of what we started with in most cell phones.

EDGE stands for “Enhanced Data rates for GSM Evolution” (or Enhanced Data GSM Environment), a 2.5G enhancement for GSM with a theoretical top speed of 200Kbps, although real-world speeds will be closer to 90Kbps.

  • Peak Speed – 200Kbps (0.195Mbps)
  • Real-World Speeds – 90Kbps (0.087Mbps)
  • Which US networks have it – AT&T & T-Mobile (in fact that’s most of T-Mobile has for data, although they are now rolling out HSPA+ in some areas)

That brings us to actual 3G data services.

EVDO Also known as Evolution, Data-Only, this runs on CDMA networks.

  • Peak Speed – 2.4Mbps
  • Real-World Speeds – 450Kbps (0438Mbps)
  • Which US networks have it – Verizon and Sprint

HSPA/HSDPA is a range of connections all that use the same standards. HSPA was adopted by most countries as it allowed for more flexibility and a better roadmap to be faster in the future.


  • Peak Speed – 3.6Mbps
  • Real-World Speeds – 1.727Mbps
  • Which US networks have it – AT&T


  • Peak Speed – 7.2Mbps
  • Real-World Speeds – 3.2Mbps
  • Which US networks have it – AT&T
HSDPA (International)
  • Peak Speed – 14.4Mbps
  • Real-World Speeds – 6Mbps
So in chart form, 2G and 3G networks looks something like this:

Home Data speeds vary quite a bit depending who you have an where you live. I’m paying for a 5Mbps connection (actually right now receiving speeds around 5.347Mbps) from AT&T Uverse which is a fiber optic connection. This apparently isn’t all that far off from your national average for an US household. In 2011, Akamai released its worldwide Broadband results, with the U.S. ranked twelfth in terms of average country speed at 5.8 Mbps. If we add the average US household Internet speed you will notice that on average it’s about what the peak speeds for 3G networks are in the US. Still faster than the typical user experience of 3.2Mbps most people will get out of 3G networks (and that’s not even assuming poor signal and other cellular issues).

The common “4G” standards and what they mean
So now we have our base line. We already know “4G” is a marketing term, but it’s what we need to deal with. Pretty much all these technologies are technically part of the “3G transitional” standard or sometimes refered to as 3.5G, 3.75G, or 3.9G, not actually 4G themselves.  However they all are the foundation to get to true 4G speeds, and in some cases (specifically wiMax and LTE) can actually become true 4G networks. Here’s what is commonly referred to “4G” and what they actually mean to you.

HSPA+ An advancement of the HSPA technology (version 7), this is something that is available in most of the world’s markets. It used to be classified by carriers as 3G. AT&T and others didn’t refer to this network as “4G” but after Verizon and Sprint started using setting up their LTE networks and touting speeds of up to 14.4, AT&T started to sat that their HSPA+ networks also “4G” as peak service of the network matched those speeds. Although the LTE networks have gotten faster, typically, at least in marketing terms, any network that uses the HSPA+ standard is still labeled “4G” to their customers.

  • Peak Speed – 21Mbps
  • Real-World Speeds – 6Mbps
  • Which US networks have it – AT&T

WiMAX or Worldwide Interoperability for Microwave Access, is a technology Sprint put themselves behind back in 2005 hoping this would become the next big cellular technology. In 2011 the technology advanced to truly be able to be called 4G because it reached peak speed of 1Gbps. However issues coming from having to share this bandwidth among handsets (resulting in drastically slower speeds for each user) and LTE adoption by the rest of the market ended with WiMAX not being the “4G” future and they’ve slowly been abandoning this for the LTE networks. Sprint, as far as I can find, never was implement this new technology as they had already decided to move to LTE. I’m adding it here for those that care, but as it’s being abandoned I won’t include it in the charts to avoid confusion.

  • Peak Speed – 1Gbps
  • Real-World Speeds – 6Mbps
  • Which US networks have it – Sprint (although they are ending this technology in phones and tablets)

DC-HSDPA also known as Dual-Carrier HSPA or Dual-Cell HSPA this technology is more common in the rest of the world, compared to the US. This is another advancement of the HSPA standard that allows for much faster transmission of data.

  • Peak Speed – 42Mbps
  • Real-World Speeds – 12Mbps

LTE is the current integration of the “4G” market speak, and a main showcase of the new iPad. The speeds vary greatly depending on where you are but many are getting around 20MBps. The downside is the implementation of LTE. It’s still in few cities, and each carrier has its own frequency. There isn’t yet a chip that handles all the different spectrums of LTE and as such, you must by the LTE model specifically for that network. iPads currently only work with the North American implication, with no other LTE chips as of yet announced for other countries.

  • Peak Speed – 73Mbps
  • Real-World Speeds – 20Mbps
  • Which US networks have it – AT&T and Verizon

How does this compare to your current cellular data speed?

You can see why “4G networks is a big deal. But with all technologies, it doesn’t end there. LTE is the stepping stone require to get the networks to LTE-Advanced, which when it comes out, is a true 4G network with speeds over 1Gbps (1024Mbps). It’s going to put what you think internet speeds for mobile devices on a whole different level. ANd perhaps for those that have it in their area, more reliable and faster than what you will be able to get in a land line.

Granted there are always those data caps to worry about on cell plans… but that’s a different story.

Categories: Tech with TaselTags: , , , , , , , , , , , , , , , , , , , , , , ,


  1. It is still confusing from an ordinary persons point of view.
    I comparative chart , links to why big diff in marketing and real output , links to which networks and countries support such networks would have just been great .

    Just my opinion.

    • I was trying to keep it simple (well simpler), and there was already tons of information to cover. There’s lots of reason why a technology has a marketed speed and a “realistic” speed. In fact many of the LTE speeds have gotten slower now that they’re much more saturation out there. Short version is that the more devices are using the tower’s bandwidth, the slower everyone’s speed get.

      Creating a post on which system works best in which countries could be good, but not sure I have enough data to really give good suggestions outside of the US/Canada.

      • ok…not techy at all.
        i currently use a prepaid service which offers the HSPA+ network for my current phone
        (samasung infuse/unlocked)

        i just purchased an unlocked LG Optimus G E973, which the specs read:
        Network Technology EDGE, GPRS, GSM, HSDPA, HSUPA, LTE
        Band GSM 850/900/1800/1900 (Quadband)

        3G NETWORK HSDPA 850/1700/1900/2100

        i just want to make sure that i understand you when you say that the HSPA+ is the same as HSDPA/HSUPA?

        pls email back a reply because i probably wont find this page again (even bookmarked)
        thank you,

  2. I am just trying to find out if a LTE phone will work on AT&T’a “4g” network. I have also seen backhaul mentioned. I have a LTE phone and the only time I can get data is in a WIFI environment. I’m wondering, is that is good as it’s going to be for a while?
    Why is it that 4g falls back on 3g and LTE don’t fall back on “4g”. I don’t know if that is possible, I just thought that I’d ask that one.
    I have been told so many stories, my head is spinning.
    Thank you!!

    • Well the technology can only work if your in an area that supports it. So if currently your LTE phone doesn’t allow you on any LTE networks, then in your area you might not have any available. So given your example, if you are on 4g (assuming you mean HSPA+) it then falls back to 3G when you get out of a 4g srea, since the 3g is pretty much everywhere these days. Many areas that have LTE ussually have a bigger area of HSPA+ around them (which is why AT&T claims a “bigger” 4G network) and as such you will drop back to whatever network is available. If that is a 3G network, then that is what it will drop back to.

      Now for your first comment… Some phones that have LTE can’t do both phone and data on LTE (in the us it’s sprint and Verizon) without the help of a second LTE antenna. Seem phones have this antenna, some don’t (the new iPhone 5 for instance doesn’t have a second LTE attenna). So currently if you have one of these phones, in theory whatever is using the LTE first will get that and the other will be forced to whatever secondary connection it has. In the future this will no longer be a problem as “real” LTE can do both. Unfortunate sprint and Verizon’s pre LTE networks weren’t designed the same way. It will, it will just take a bit of time to update it.

      I hope this made things a little less confusing.

      (FYI I’m not per say pro AT&T with the LTE debate, but LTE is actuslly an extension of the gsm network technology, and as such AT&T just has a leg up with that, whereas Verizon and Springt are coming from CDMA networks and have a bit more catching up to make their LTE in line with the technology behind AT&T’s networks)

      • I need to correct some misinformation that is out there about why some phones can’t do voice and data at the same time on the Sprint and Verizon networks. The current state of LTE technology allows data transfer only, meaning no voice calls can be made on the current LTE networks. Voice calls will be allowed in the future, just not yet. CDMA on the other hand has the opposite limitation. It can make calls but no data transfers. Sprint and Verizon both use CDMA to make voice calls while just about everybody else uses GSM which can make both voice and data calls. What this means is that to do a voice
        call while transfering data requires two radios (in technobabble they are called transceivers) one to do the LTE data transfer and the other to do the CDMA voice call. By the way, to meet the radio receiver sensitivity requirements of the LTE standard every LTE enabled phone has two antennas. The extra CDMA radio would use a third if it were present. I presume the reason the iphone doesn’t support simultaneous voice and data on CDMA networks is to reduce complexity and also reduce power consumption.

  3. ITALY: Considering your article and the specs of dc-hsdpa you put into it, i think in Italy we are starting dc-hsdpa (as i saw the faster data key specs equals to 42.2 Mbps that as usual i think deals with the peak speed and not the real world one). It will be good that different Countries guys post comment like mine to understand the world diffusion of these standards :). Very good article thanks a lot!!!

  4. This is a very good post. I like the bar charts. T-Mobile advertises that its 4G network is faster than AT&T, but in small print they clarify that comparison does not include LTE! So a lot of misleading info out there.

  5. from what I understand HSPA+42 and DC-HSDPA is one and the same (a faster,updated 3G technology).
    Can you please confirm my theory, because 3network is releasing DC-HSDPA in 2013 and I’m buying HSPA+42 device from the US and would like to know whether I’ll be able to use DC-HSDPA speeds???

    • From what i’ve found, they are the same in terms of most aspects, but DC-HSPA allows for dual channel connection (aka 2 sets of signal to the cell tower) which allow for a faster connection. So a phone that supports HSPA+ (which I’m assuming the branding of HSPA+42 is just a variant or marketing branding of) could run on DC-HSPA networks, but wouldn’t get the full power of the connection as it would only be sending a signal signal instead of 2. It’s possible that HSPA+42 is t-mobiles marketing term for a DC-HSPA here in the usa (since we are used to the phrase HSPA, and DC-HSPA might confuse people), but I haven’t found anything that can confirm that.
      I’ve have updated the article to reflect that information that i was able to confirm though.

  6. The 3UK Network here in England already has HSPA+ up and running as of 2011. They are now rolling out DC-HSDPA and are hoping to have 50% of the UK done by the end of 2012. Then in 2013 they aim to finish and will also begin [after the Auction of the new available spectrum] start installing LTE.

    Here is a link to their blog with the details

  7. Tasel, great article and description of the networks. I have a question about the iPhone 5, they say it’s an LTE phone, but when the real true 4G LTE is offered by carriers will the iPhone 5 be compatible with this new speed or will it require a new device to handle true 4G LTE? For example people using factory unlocked iPhone 5’s with tmobile, if tmobile releases true 4G LTE (assuming the can jump over today’s “4G”). Thanks.

    • Everything I’ve seen points to the fact that LTE Advanced will be using a different antenna architecture (or at the very least different packet usage) and wider spectrum range from LTE Lite.

      One of the ways that companies are rolling out the 10th version of LTE (to get “advanced”) is to bond two LTE antennas together, much the same way DC-HSPA does. This gives more bandwidth, and therefore faster speeds. Another problem is that LTE Advanced uses more spectrum to push the data. It takes a large chunk of spectrum and combines it to create a large channel the phone and cell tower can use. Current technologies use much smaller slices of the spectrum. So between these two hurdles, unless Apple has built functionality into the iPhone 5 that they haven’t announced/people haven’t found, It’s unlikely that it will be able to take advantage of this.

  8. you forgot UMTS. i think:

    GPRS – G on phone’s icon
    Edge – E on phone’s icon
    UMTS – 3G on phone’s icon
    HSDPA – H on phone’s icon
    HSPA+ – H+ on phone’s icon

    dont know the rest since i havent seen it yet.

  9. Hi Tasel,

    I find your post very clear and informative. I’ve run into a problem lately since I bought my AT&T iPad 4. I am spending my next year in the UK and South Korea, where LTE-speed network (or whatever it’s called) is available. And as far as I know different carriers in the world operate on different frequencies, so I’m not sure if my AT&T iPad will be able to take full advantage of LTE networks in those countries. When I check iPad 4’s tech specs on Apple website it looks like only Verizon iPad will work with more overseas carriers while AT&T iPad will not. I travel a lot so this is a big concern for me could you give me some insights into this?

  10. would you please tell me that at which location these tests were conducted?

    • The information I gathered came form both my own tests (in the NYC area) as well as sourced speeds form CNET, PC Mag and other online sources (that ran their test around the US) that I averaged together to try to find what “most people” would be expecting. For HSDPA I got test that had been run primarily in Australia and Germany if i’m remembering right. Granted this post is now over a year old and both bandwidth on the many of the network, as well as the traffic on them have changed since this posting.

  11. Muy buena su información aunque todavía me cuesta entender mejor esos conceptos. Pienso comprarme un iPad 128 4G , qué opina del mismo?

  12. Now you can see to what cellular radio network the iphone is connected to:

  13. Well I am in Malaysia and I am accessing the internet over DC-HSPA via one of them telcos ere. It sure it usable for browsing even tho streaming videos can be a bit lagging at times but that doesnt bother me much because i seldom stream videos due to quite high charges imposed on data around ere.

  14. Excelent post… the only thing I have to say here is that 1 Gbps is not 1024 Mbps.. It’s actually 1000 Mbps (International Unit System).

    1Gb = 1000 Mbps

    When we speak about sizes (probably reffering to binary files), we should use the term gibibit, which in that case is 1024 Mebibits..

    1Gib = 1024 Mibits

    Anyway.. Thank you for the information.

    • It actually depends on who is speaking about the speed… most software vendors define 1Gibit = 1024 Mibits due to it being based on a binary system. However, most hardware manufactures define 1Gbit = 1000Mbit.. ussulay there’s no sign which measurement is being used since they just use Mb and Gb.

      So for example your hard drives are actually measured in a decimal format, while your software reports it’s storage actually as a binary system. Which is part of the reason why there’s usually a discrepancy between what you buy and what you get. So when you buy a 100GB Hard drive, you often end up with instead only 95GB available due to the difference. The other part has to do with directories and such but that usually is fairly a small amount.

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