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Hspa+ vs. LTE

Discussion in 'Off Topic' started by Socrats, Sep 20, 2011.

  1. Socrats

    Socrats Member
    Thread Starter

    I'm pretty confused. I'm wondering what's the difference between hspa+ and LTE? I know verizon currently has LTE and At&t has hspa+ but what is the difference between the 4g speeds , I mean 4g is supposed to be (100 mbps ) right? Also why does At&t call their 4g phones , "4g" when they are going to LTE for 4g speeds so doesn't that mean hspa+ phones are a ripoff, and you wasted you're money on a 4g paperweight?

  2. alostpacket

    alostpacket Over Macho Grande?

    Technically 4G is supposed to be like 1Gbps -- so none of those are "technically" 4G.

    4G is supposed to mean various other things too, such as less than 100ms of latency etc.

    But as for HSPA+ vs LTE, the reason ATT is switching is anyone's guess.

    HSPA+ max is 42mbps and (current) LTE is like 50?mbps.

    Real life speeds however for both are much slower

    HSPA+ are seeing like 5-20mbps and VZW LTE are seeing like 5-25mbps. WiMax is somewhere in the same area too.

    It's all marketing really. 4g isn't really a "mature tech" as of yet. They are all nicely faster than 3G, but none are technically 4G, and some of them are changing technologies/spectrum/etc.

    If you must have 4G, then VZW and Sprint are probably the most stable in terms of roll-out plans. But I think any phone you get with any carrier will have some nice speeds for the next year or two at least.
    Montoya, pham818 and Harry2 like this.
  3. vikingjunior

    vikingjunior Well-Known Member

    The reason for LTE is spectrum efficiency. It wouldn't get bogged down with so many users on it. Hence why now Verizon is throttling 3g users and LTE customers have unlimited data.

    In another word it's all about using one's spectrum wisely as there is only a certain amount to go around.
  4. Guamguy

    Guamguy Android Expert

    3G and 4G are classed by speeds. 4G is actually 100mbs, which none of the current technologies attain except LTE-Advanced.

    Yet what we call "4G" currently is because they're just faster than 3G (1-2Mbs), and so are really more like 3.75 to 3.9G. HSPA itself can be classed as 3.5G.

    If you look deeper however, they can also be classed in terms of technologies. The most important of which is Multiple Access. This is how a station can identify a single mobile from hundreds of others in the same area, read and send to it, while doing the same on hundreds of others.

    Classic 2G GSM techs are TDMA or Time Division Multiple Access. This means every terminal is given a tiny sliver of time to send and receive information. In other words, they take turns. This includes the data forms of GSM, which is GPRS and EDGE.

    CDMA means Code Division Multiple Access. It means every terminal has a special code and the station recognizes each terminal through this code. The coded transmission is expressed using spread spectrum techniques. Although we associate "CDMA" with CDMA, what we call 3G GSM, aka UMTS, and its related technologies, HSPA, HSDPA and HSPA+, all use W-CDMA or Wide Band CDMA as its air interface While it may use SIMs and GSM base stations, UMTS actually uses a transmission interface method akin to CDMA.

    3G "CDMA" as you know it from Verizon, Sprint, etc,. is also known as CDMA-2000. Again, the only thing is shares in name with UMTS is the similarity of the air transmission and multiple access technology, which is code division. This is where you see the 1X, 1XRTT or 1XEV-DO.

    LTE and WiMax evolves from CDMA type techs and uses a technique called OFMDA or Orthogonal Frequency Divide Multiple Access. This is a bit difficult to describe, so you can read it here. To make it short, the claimed benefit of OFDMA is higher spectral efficiency, speed and density over CDMA.

    Orthogonal frequency-division multiple access - Wikipedia, the free encyclopedia

    The second characteristic of 4G is the use of MIMO or Multiple Input Multiple Output antennas. MIMO also increases spectral efficiency and density over traditional antenna design. You would be familiar that some wireless routers, like the ones you see with three antennas sticking out, are using a simple MIMO design.

    MIMO - Wikipedia, the free encyclopedia

    So basically, both LTE and WiMax uses OFDMA with MIMO techniques.

    HSPA+ is basically HSPA added with MIMO.

    Some more references here.

    WiMAX - Wikipedia, the free encyclopedia
    Montoya, stpbby, dan330 and 1 other person like this.
  5. MyNamesTooLong

    MyNamesTooLong Android Expert

    Why worry about it? Your speeds wont match the speeds they say they are capable of and if they did it would be short lived thanks to them throttling the data...and now to be helpful. Yes "4G" is noticeably faster than 3g(I have t-mobile) So much so, I had to pick up a 4g back up phone because using the web on 3g after having 4g was unbearable(and I am absurdly impatient) So yes, the 4G is worth it
  6. ttriarsi5689

    ttriarsi5689 Lurker

    I have noticed, having used both LTE and HSPA+ phones, that the speed difference goes to LTE, but there seems to be more HSPA+ coverage, and HSPA+ seems to be more battery efficient, where when you have LTE on all day your battery will drain very fast.
    Crashdamage likes this.
  7. Demache

    Demache Android Expert

    Not sure about how LTE works on GSM phones, but on CDMA phones, the CDMA radio has to be on alongside the LTE radio (2G is still used for phone calls). So essentially your phone is maintaining two seperate signals which is naturally going to strain the phone a fair bit harder.

    Either way, unless I know I won't have access to a charger for a significant amount of time, I will take the speed boost of 4G LTE over 3G EVDO.
  8. BigCiX

    BigCiX Android Expert

    In my area I'm lucky to get 3 mbps on my 4G (hspa) device.

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