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Tuesday, October 14, 2008

Question: what happens if a PC has both WiMAX and 3G/LTE?

This post is a question, rather than an opinion.

There seem to be two clear trends:

- An increasing % of PCs will have 3G radios, either with internal modules or external dongles
- A small number of PCs now have integral WiMAX and there are also dongles emerging. This will also increase, although it's certainly a lagging trend at present.

We know that vendors like Ericsson, Qualcomm, Huawei and peers are continuing to be aggressive on both 3G module and dongle pricing, as are mobile operators.

And based on past history, we can be fairly confident that Intel is going to price its combined WiFi/WiMAX modules at a level to encourage uptake versus plain WiFi, especially when bundled with its processors. When Intel first launched Centrino in 2003, the extra cost of WiFi was $20 above the standalone processor price. Its initial WiMAX+WiFi modules are $24 more than standalone (802.11n) WiFi. WiMAX dongles will probably fall rapidly in cost too.

In other words, it's seems quite possible that we'll see PCs with WiFi, WiMAX, HSPA and (with Qualcomm Gobi) possibly EVDO as well.

At present, 3G and WiMAX operate in different bands - WiMAX at 2.5GHz (or occasionally 2.3GHz or 3.5GHz), with 3G at 850/900/1900/2100MHz.

At some point, we'll also see 2.5GHz bands for LTE and HSPA, and possibly also other mixed "technology neutral" bands thanks to various ongoing regulatory efforts by the likes of Ofcom and CEPT. But for now, I think we can be safe that we won't get dual radios in the same band.

What's really opaque to me are a few issues:

  • Will 2.5GHz TDD WiMAX and 2.1GHz FDD 3G interfere significantly if both radios are on simultaneously? (Possible with 2.4GHz WiFi and Bluetooth too).
  • Are there any connection managers that can handle all of these, or will such "dual WWAN" PCs end up with multiple bits of software? Early reports suggest the current software experience on Xohm is a bit clunky.
  • Are there any technical or commercial reasons (apart from outright cost) to stop OEMs putting both WiFi/WiMAX and 3G modules in the same notebook? Does it need more complex antennas?
  • What happens if you have an embedded-3G notebook with a WiMAX dongle, or vice versa?
  • Is it possible to create a combined HSPA/WiFi module which *doesn't* need a SIM card inserted for authenticating the WiFi?
(Before anyone else mentions it, yes I know that having 4 radios on simultaneously is a great way to kill the battery, irrespective of anything else).

If people are prepared to pay the extra $50-100 for a 3G module today... and if it's going to fall to $30 or more in a couple of years' time.... then presumably a fair proportion will then be willing to pay an extra $15 (say) to have WiMAX too, especially if they expect to travel to places where there are competing networks.

1 comment:

  1. Anonymous10:50 am

    Hi Dean,

    Here are my personal thoughts on the subject.

    Q1
    Will 2.5GHz TDD WiMAX and 2.1GHz FDD 3G interfere significantly if both radios are on simultaneously?

    A1: Interference is something that manufacturers deal with constantly.
    This was also the case with WiFi/3G datacards. I don't expect any major stumbling points or delays because of it.

    Q2.
    Are there any connection managers that can handle all of these, or will such "dual WWAN" PCs end up with multiple bits of software?

    A2.
    Yes, there are already Connection Managers in the market that address multiple bearers. Of course there are also some that don't. Whether you see "bits" or a "combined" offer will depend on the OEM and MNO choice. But there is not offer limitation.

    Q3.
    Are there any technical or commercial reasons (apart from outright cost) to stop OEMs putting both WiFi/WiMAX and 3G modules in the same notebook?

    A3. My personal fear is heating and "radiation". Just like I would not buy a house under huge powerlines, I would not want 6 different radio's "warming" my privates ;-)
    I also notice that this topic is not covered anywhere. But do we know the longterm affects of all this?

    Also, I am a big proponent of "crawl before you walk and run".
    In other words; we are just getting around to making embedded 3G a viable option, where the activation still needs sorting. Adding Wimax into the mix now, just slows this process. So no, i would not suggest embedding Wimax now. I think, short term, this should 3G or Wimax, not both (yet).

    Q4.
    What happens if you have an embedded-3G notebook with a WiMAX dongle, or vice versa?

    A4.
    Nothing. It will work fine. At the end of the day they all are basically USB type devices. So whether embedded or dongle it does not matter. Most embedded 3G modules are in fact renamed 3G datacards.

    Q5.
    Is it possible to create a combined HSPA/WiFi module which *doesn't* need a SIM card inserted for authenticating the WiFi?

    A5. in the case of EV-DO networks there is no SIM and there are already many cards in the market that do both cellular and WiFi.
    So this exists.

    But I suspect your question is whether you can do EAP-SIM without a SIM. First of all, I am not a big fan of EAP-SIM. Some OEM's like (SonyEricsson and Huawei) do not always expose a SIM reader in their cards (they do this to save cost). So there is already a reason to be against EAP-SIM as it is not standardized. Plus, the AT+CSIM command fallback for SIM authentication does not always work either. However, why would we want to do WLAN authentication via the SIM anyway? What does it add?
    In fact, it forces me to keep my 3G device powered on even if i just want WiFi access.

    Aren't we better of using a usernam and password via Wisp-R? Many OEM's offer a portal where people can login and buy stuff or manage their account. Why not use this account instead? Then you can use WiFi even without a 3G device.

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