WirelessMoves

Here's an interesting piece of technical insight I gained this week when going through 3GPP TS 23.401 concerning tracking area updates that I haven't seen when I went through the spec for my SAE review posts back in February (part 1, part 2 and part 3):

In UMTS, location area and routing area udpates are only done when the mobile is in idle state, i.e. no physical link is established on the high speed shared-, dedicated- or forward access channel. This makes sense as in these states the RNC in the access network is aware of the location anyway and can report location changes to the core network when necessary. Only once the mobile goes to idle state and the mobile makes the decision to go to another cell on its own without reporting back, routing and location area updates come into play if the new cell is outside the current area.

In LTE, the corresponding procedure is called a tracking area update. The first difference to the LAU and RAU of UMTS is that the mobile can have a list of several valid tracking areas and an update only has to be made if the new cell is in a tracking area that is not part of that list. So far so good. TS 23.401 chapter 5.3.3.0 says, however, that a tracking area update is made in both idle and connected state. Quite a surprise to me so I wondered why an update is necessary in the connected state!?

The answer to that question can be found in the message sequence charts for handovers. For example: during an X2 handover, which is directly negotiated between two base stations, the Mobility Management Entity (MME) in core network is only informed of the handover after it has taken place. Also, there's no direct communication between the MME and the mobile device during the handover procedure. That means that in case the new cell is in a new tracking area, the mobile has to update its tracking area list as that information was not contained in the handover messaging.

From a logical point of view that also makes sense. Traking areas are administered by the core network (by the Non Access Stratum) while handovers are performed by the access network. Also, the signaling does not interrupt the user data transfer so there are no side effects of performing this procedure in connected mode and while transferring data.

More LTE technical tidbits this week also over at Wired n' Wireless.

I know I won't get a real good answer for this one but I was just wondering of how much in the current set of 3GPP specs is no longer used at all anymore and, even more interesting, how many features and options specified over many years never made it to real networks!? With tons of features specified in each new release and only a few really used, I assume it should be a sizable percentage.

Why I care? Well, when reading the specs it's often not only difficult to interpret what is written but also if what you are just trying to figure out already is or will be used on day. Is this the price to pay for having one system to which (almost) everyone contributes to? What do you think?

I've recently had a chat with a friend on different 3G price models and I thought I'd write down a little overview to document the diversity of the tariff landscape in Europe today:

Let's start with examples from Germany: Here, a popular post-paid model is a fair use all you can eat plan with a volume cap, for example 5 GB, after which the bandwidth is throttled down to 64 kbit/s for the rest of the month. While staying within the bucket, speed is only limited by the device, network capability and radio conditions. Prices for such plans range between €30 and €40. Other volume caps also exist.

In the pre-paid sector, there are many offers for small screen devices billed per MB. Prices range between 20 to 40 euro cents per MB. Great for low to medium use with OperaMini and e-mail without attachment download. Some operators are also offering prepaid plans for notebooks with volume caps of a couple of hundred MB to a couple of GB for prices anywhere between €20 and €40. Vodafone and others have offers based on time, for example 24h access for €5 and a week for €10 with a volume cap at 1GB. If you dig a bit deeper the weekly package can also be had from a reseller for €6.99.

Finland: Here, Saunalathi Saunalahti offers unlimited bundles and charges based on maximum throughput. Prices range from €9.80 with a speed cap of 384 kbit/s up to €34.90 for a throughput of up to 5 MBit/s Gbit/s.

Austria: The el dorado land when it comes to mobile. Drei (Hutchison 3) sells 15 gigabytes a month for €15on a postpaid contract. Prepaid contracts are available as well, like for example those of Mobilkom and One, where €20 buy one gigabyte that can be used over 12 months. Maybe not very attractive from a price per GB point of view but for occasional users it's an unbeatable monthly price.

France: Here, clocks are still ticking differently compared to pretty much the rest of Europe. Orange for example offers 1 GB of traffic on a post-paid basis for €39.90 after which the bandwidth is throttled. 4 GB are offered for €79.90. Prepaid packages are only available on a time basis. 20 minutes go away for €3, an hour can be had for €8, six hours cost €25 and if you want to be connected for 12 hours over the duration of one month, you have to invest a staggering €35. Nothing really for always on connectivity fans.

Feel free to add to the list if you know of yet another variation.

Here's an innovative mobile service from the German Postal Service (Deutsche Post, DHL) I think I will use more often from now on: My big problem when getting things via mail is that I am usually not at home when the parcels are delivered. That leaves me with guessing when the parcels arrive, go home early to pick up the delivery failure notice and then drop by the post office before it closes in the evening. But now there's a better solution for it: Close to my office there's a so called "Packstation" to which my parcel can be delivered. Once it's there I automatically get an e-mail or SMS to inform me that I can pick it up. Great, I just have to walk over, insert my customer card, type in the PIN and the parcel is mine. Great mobile service, that's how I like it!

This September the EU mandated a maximum price wireless network operators could charge each other for GPRS and UMTS data roaming. The cap imposed was one euro per megabyte and the hope was that as a result, end user prices would fall as well. So has it happened yet?

Taking my German prepaid SIM from MVNO Congstar to France recently, I was greeted with an SMS message informing me that data roaming charges were 99 cents per 50 kb and in addition a daily service charge of 49 cents would apply. That's a whoppin 20 euros per megabyte! Orange France is not much cheaper. Their prepaid roaming charges for data in Belgium is 9 cents per 10 kb or 9 euros per megabyte.

Well, Ms. Redding, I guess the plan hasn't quite worked so far and I still have to rely on local SIM cards.