Called 'Mc-Do' in Paris, I have to admit that I am not really a frequent customer and so I've never considered using their free Wi-Fi so far. However, last week I had a bit of time so I thought I'd give it a try. I didn't know what to expect so I didn't really expect much. The more was I surprised that access is granted without any kind of verification if you bought something or not, e.g. via a code on the receipt. The positive surprise didn't stop there as I got a downlink throughput of 5 MBit/s and even my PPTP VPN client could connect to my home network and ensured an encrypted connection via the unsecured hotspot. And I was not the only customer with a notebook / netbook in the restaurant I might add. By the way, the others had some food and drink on their table as well so it wasn't a free lunch, eh, Wi-Fi.
I've been wondering for a long time when 3GPP would finally define the band for the European digital dividend, i.e. spectrum between 790 and 862 MHz. Looks like they've finally done it: With v9.2.0 of TS 36.301, released at the End of December 2009, Band 20 with 791 - 821 MHz in downlink and 832 to 862 MHz in uplink now covers that area.
Interesting detail: The downlink is in the lower range. I assume that was done to keep the UEs uplink transmissions as far away as possible from the spectrum still used by TV. Anyone got more inside on this?
One of the good things about LTE is that especially in the radio network, it represents a fresh start so a lot of "optionality" that tends to bloat a specification over time is avoided in the general baseline. To see what I mean, let's compare the Radio Resource Control (RRC) specification of UMTS with LTE:
The original Release 99 UMTS RRC specification (3GPP TS 25.331 v 3.1.0) is about 865 pages long. In Release 8, the same specification document (v 8.1.0) now contains 1435 pages.
The RRC specification for LTE can be found in 3GPP TS 36.331. The December 2009 version (v.8.8.0) contains 208 pages. That's only a fraction of even only the R99 UMTS specification.
I am a bit surprised the volume difference is this big. I compared chapter headings to see if there are things that the UMTS RRC spec contains which are not in the LTE RRC. However, it all looks pretty similar.
For all of you interested in the past and future of wireless, here's a link to a video interview with Martin Cooper, who created the first portable wireless phone back in the 1970's at Motorola. Great insights into how everything started and great ideas on what will happen next and what shouldn't. Enough said, if you have 32 minutes to spare, head over and enjoy. And if you have the time later, bookmark this and return later :-)
Back in 2007 I wrote three posts about Continuous Packet Connectivity (CPC), a bundle of 3GPP features aimed at improving network interactions for applications on 3G HSPA devices that only require a low bitrate or only poll the network periodically (e.g. once every few minutes).For details see here, here and here. All these features were part of 3GPP Release 7. One important feature was missing though, and that was to improve uplink speeds and reaction time in more power efficient states. This feature was added in 3GPP Release 8 in the "Enhanced Uplink for CELL_FACH State" Work Item. For details see RP-070677.
And here is what the feature actually does:
Today, when a HSPA mobile device is not in the Cell-DCH state, i.e. it is not observing and receiving data over the High Speed Shared Channels, but is instead in the less power consuming Cell-FACH, Cell-PCH or URA-PCH states, uplink packets are sent over the Random Access Channel (RACH). While this works quite o.k. there are several shortcomings:
The capacity of the RACH is very limited. Hence, when the network detects that a device uses this channel for more than just a small IP packet or two, the connection is immediately transferred to the fully active state (Cell-DCH). That requires a lot of signaling and in case the mobile ceases transmission again afterward, e.g. because it only wanted to send a keep-alive or poll message, it wastes capacity in the cell.
State transitions from Cell-FACH to Cell-DCH take some time, in the order of hundreds of milliseconds, so it has a negative impact on user experience.
As capacity on the RACH is very limited, only few users can use it at a time.
Round trip delay times due to the use of the RACH are in the order of 250 to 300 ms compared to far less than 80 ms in fully active state.
Only very small data packets can be transferred in on RACH slot. The document linked above contains an analysis that comes to the conclusion that an IP packet with 500 bytes requires over 10 RACH transmissions.
O.k., so what is the solution!? Instead of the RACH, Release 8 has specified how to use a fast Enhanced Uplink Channel (E-DCH) that was originally specified for HSUPA. This E-DCH is configured with default values, i.e. a modulation and coding scheme that is conservative enough so even devices at the edge of a cell can use it. No power control and channel quality feedback is necessary. Access to the channel is controlled by the network with the Acquisition Indication Channel (AICH) as before.
Looks like a very worthwhile feature to me, let's see when it appears in practice.
I really really really like my netbook, it is so convenient, especially when traveling and not having a lot of space. But one of the things that is missing is screen real estate, especially on the vertical. My Ubuntu and the Gnome GUI make good use of what's available as the icons and window frames are smaller than on MS Windows. But even with MS Windows, working with a netbook should be o.k. But what about Microsoft Office that uses a ribbon interface instead of the traditional menu / icons on top of the window? The height of the ribbons costs precious vertical space and as far as I know there's no way to change that!? So I wonder if Microsoft at some point will come with a netbook / small screen optimized UI for its Office suite!?
What about you, how do you feel about 'ribbons' on smaller screens?
I've done a couple of looking back a bit into the past posts recently so it's time again to look a bit into the future. Today we are at 3GPP Release 10 in standardization and when I look back to Release 99 or even further, we've come a long way. So, will I or 3GPP still be around for 3GPP Release 20? With a release cycle of about 18 months, that should be in 15 years from now. I wonder how wireless networks will look then!? Will there be a similar difference compared to Release 10 to GSM Release 97? That's difficult to imagine. But then, who back then working on Release 97 could have imagined HSPA+ or LTE?
With the digital dividend band in Germany about the be auctioned in April this year, it's interesting to see under which conditions spectrum spectrum will be sold to the highest bidders. As the 800 MHz band is ideal to bring high speed Internet to undeserved rural areas, the auction conditions set by the "Bundesnetzagentur" contains the following conditions:
By 2016, 90% of the population of cities and areas selected by regional governments (Bundesländer) must be either served by high speed wireless or wireline Internet access. Small villages will get precedence over larger towns by grouping them into 4 priorities:
Priority 1: Areas and villages with a population less than 5.000 inhabitants
Priority 2: Towns and areas with a population up to 20.000 inhabitants
Priority 3: Cities up to 50.000 inhabitants (are there any such cities in Germany left that don't have 3G or DSL coverage yet???)
Priority 4: Beyond that, anything goes
Priority 2 towns can only be served once at least 90% of the priority 1 areas are covered, and so on.
For more details, click on the link above for 181 pages of nitty gritty details.
And another interesting chart from Telecom Austria's recent annual financial report. Page 31 shows how over the past years, fixed an mobile network operators in Europe have started to re-integrate again to leverage their fixed and mobile assets for combined offers to customers and to benefit from a common network. One of the few places where the trend has not stuck is the UK. Bad luck for BT in my eyes who was just a bit too quick to sell off their mobile business at the time.
It's still early days though and I haven't seen a lot of products coming out of such re-integrations yet. But let's see, maybe in two or three years there will be a chart that shows in which countries combined offers beyond a single invoice are on the market.
France is one of the countries in Europe where the 900 MHz band has been opened up for technologies other than GSM and where a 3G network operator has started deploying UMTS 900. Some UMTS 900 / 2100 MHz USB sticks have been available for a while and especially Nokia puts UMTS 900 MHz into a number of its higher end devices in addition to the standard 2100 MHz band support. Here's a link to the coverage map of Orange France that shows which areas are covered with the standard 2100 MHz UMTS band and which are covered with UMTS 900.
It's interesting to compare those maps with satellite maps to see what kind of areas are covered with UMTS 900. It's very rural areas indeed so it looks like Orange sees a business case for covering such sparsely populated areas with a frequency band on which the signal can travel much farther than on 2.1 GHz. Also, it proves my assumption that especially in rural areas, there is enough bandwidth available to run both GSM and UMTS alongside each other, have enough bandwidth for GSM voice and data and still enough space between the technologies to keep the interference between the technologies on the air interface in check.