Throtteling at the Base Station

Most "all you can eat" wireless Internet access offer these days do come with a traffic limit per month after which the connection is either cut, the speed is decreased or further charges apply. The aim of these measures is to ensure that a few users do not disproportionally use the network. Especially in wireless networks, where air interface capacity is the limiting factor, network operators try to bring some fairness into the game. However, the throttling is not happening at the air interface but in the core network. For the sake of fairness, however, I wonder if that is the right place to do the throttling!?

Wouldn't it be better to to have a sort of a soft limit and control it via the base station traffic scheduler? Here, the scheduler could take into account how much data each user has already transmitted in the past hour or day and thus give the packets to or from this user a higher or lower priority. Doing this at the base station would have the advantage that while the cell is not loaded, even heavy users get the full bandwidth while under heavier load, users that only browse the web get a higher priority and are thus not significantly slowed down by streaming or downloading activities of other users.

The scheme doesn't work for moving users but I assume that most power users with a notebook use bandwidth hungry applications in a stationary mode. I am also aware that taking the user identity and past use into account at the base station scheduler is not standardized in 3GPP and I am not sure if the base station scheduler can keep track of a users identity over state changes (i.e. from Cell-DCH to Cell-FACH to Idle and back). Nevertheless, an interesting "Gedankenexperiment".

Oh yes, and by the way, this kind of soft-priorization is not new, it's done for satellite Internet connections already.

4 thoughts on “Throtteling at the Base Station”

  1. Hi Martin, Ericsson has talked about a roughly similar idea at their Capital Markets day for analysts earlier this year. I don’t know exactly how it works, how much it has been deployed or whether others also do it, but here’s a nice slide about it. For (very little) more info, see the Speed of Change presentation at that capital markets day (Ericsson investor website for webcast) and also try googling “Ericsson traffic handling priority”.

    On a related topic, I have recently thought of a curious thing you might want to think about regarding AT&T’s 7.2Mbps network upgrade: many people are surprised that they are not going for 21Mbps HSPA+… However, there is a third option nobody is mentioning!

    When Signals Research used Telstra’s network to test USB devices, they suddenly managed to achieve 8Mbps aggregate throughput with 7.2Mbps devices on a single sector if a single-channel network cell. Apparently, the cell had already been upgraded to, iirc, 10.2Mbps and the devices could share the wider channel!

    Is it possible that AT&T will do the same thing, hiding the fact that some cells are 14.4Mbps-capable (per channel, so some might even be 28.8Mbps total, multiplied by 3 sectors!) – this only makes sense with high-backhaul cells of course (i.e. Fiber). Given the near-zero benefits of 64QAM/MIMO in bad conditions (where users are most likely to complain) or on 7.2 devices (aka every current and planned iPhone), and the necessity to keep user expectations relatively low, it’d seem like a good plan to me.

    What do you think? Do you believe as I do that it’s both technically possible and relatively easy to do on new equipment? Am I right in assuming it’d noticeably increase spectrum efficiency?

  2. Hi Martin

    Interesting article. I have been thinking the same for quite some time. In India 3G hasnt rolled out yet, but as of now service providers offer EDGE and they give away unlimited data connections on mobile phones. But there are few service providers who have their 3G network ready and have rolled out USB sticks over the same. They are offering 3Mbps speed with a data limit of Max 15 GB and this restriction is coming from government.

    I am really curious to see how service providers will bring out the data services on mobile when 3G comes out. If they give away unlimited data connections over mobile and restrict data over 3G stick, then people will start using their mobiles as 3G modems and probably choke up the network. On the other hand if the data is limited on mobile phone then all the blackberry users in my office will be unhappy. Any thoughts?


  3. Hi Santosh,

    yes, I wonder how they want to distinguish between the two different usages. From a connection point of view they can’t. They could restrict the use of browsers to identifiy mobile vs. PC use but that can also be easily circumvented by savy users. Also, with devices like the iPhone etc. that load full pages rather than mobile or compressed pages, from a volume perspective there’s really no difference anymore to a full PC connected to the Internet (though I much prefer Opera Mini for speed, availability, etc.).

    Martin wrote:

  4. Martin, I live in Brazil and we have a huge problem concerning broadband here. Unfortunately, ADSL and cable reaches a small part of the country, and 3G is being used as main connection for a great number of brazilian citizens.

    As carriers are worried about 3G traffic limit, on the other hand we see a great solution for digital and social inclusion. And carriers themselves are selling so much 3G modems that they haven’t seen a slight sign of crises around here.

    That’s the rub…

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