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Next Tuesday, December 12th 2006, the bidding for WiMAX licenses in Germany will finally commence. Updates throughout the bidding process will be published life on the Internet at the Website of the Bundesnetzagentur. Here are some facts behind the auction:

Technology Neutrality

The licenses being auctioned are not reserved for a special technology. Thus, the title of this entry is not quite correct. However, it is expected that WiMAX will be the technology used by companies interested in this spectrum to provide broadband wireless access.

Bidders

It’s not quite clear yet who is going to bid for the licenses, it seems to be a well kept secret by the Bundesnetzagentur until Tuesday morning. The Deutsche Breitband Dienste GmbH, also known as DSLonAir, has publicly stated that they will participate, so at least one contender is known. They’ve also publicly stated that they are interested in getting a nationwide license.

Regional Licenses and Coverage Commitments

In total, four licenses will be auctioned for 28 regions. In order to provide nationwide service a company needs to get a license in all regions. The starting price for a region depends on the population density and prices vary from 300.000 euros to about 1.8 million euros per region. To get a license for all regions the starting price of the auction is about 16 million euros. As there are four licenses per region, the minimal revenue for the state, should all licenses in all regions be taken, is 64 million euros. Licensees are required to cover at least 15% of the towns in each region by the end of 2009 and 25% of the towns at the end of 2012.

Frequency Bands Being Auctioned

Each license covers a paired 21 MHz channel, i.e. two 21 MHz channels with a duplex distance of 100 MHz between 3410 – 3494 MHz and 3510 – 3594 MHz. It is left to the digression of the company using the frequencies to use frequency division duplexing (FDD) systems which requires paired spectrum or if time division duplexing (TDD) is used which does not require paired channels. According to a recent Intel Whitepaper (page 8), WiMAX 802.16e will use TDD in this frequency band. The white paper also states that in this frequency band channel bandwidths of 5 and 10 MHz are specified. This means that a licensee can operate four independent channels with one license.

Auction Result Depends on Competition

As except for one company the names of the bidders are not yet known it remains to be seen how many of the interested parties will go for a full nationwide coverage and which are only interested to cover certain regions. As there are four licenses per region at least five of the six companies would have to bid in each region in order to significantly increase the minimal price. So what would be a price for the licenses which would still be realistic? Well, let’s make a quick and dirty calculation here: Let’s assume all four licenses are awarded in all regions and the companies are able to get 10% of the population of Germany, which would be 8 million people, to subscribe to services over a period of 15 years. Let’s further say that licenses should cost no more than 1 euro per subscriber per month. Let’s also leave all other complicated stuff like interest, network ramp up, etc. out of the equation for the moment. Thus, the maximum sum bidders would be prepared to pay equals 8 million subscribers * 1 euro * 12 months * 15 years = 1.4 billion euros. This would be 360 million euros per licensee. Sounds like a huge sum, but compared to the 50 billion euros spent for UMTS licenses it would still be a bargain.

Of course the three big unknowns in the equation are if there is enough competition to get such a sum, if companies are willing to shed such a lot of money up front and of course if WiMAX networks will be attractive enough to get a penetration of 10% of the population. Much depends on how these networks will offer their services. For more on this, take a look on my entry on "WiMAX Culture: Hotspot or 3G".

Quite a number of 3G UMTS networks have been upgraded over the past year to HSDPA (High Speed Downlink Packet Access) which boosts data transmission rates from about 384 kbit/s to over 1 MBit/s in a first step. The second step of HSDPA, with data rates of over 3 MBit/s, has also gone life in some of networks already. So far, there were only PC data cards which were HSDPA capable. But now it looks like the first HSDPA handsets are close to market readiness.

In Europe and Asia, the Nokia N95 for example will surely take full advantage of HSDPA with it’s built in multimedia and Internet applications. For the US, where different frequencies are used, it looks like Samsung will take the lead with a new HSDPA smartphone called "Blackjack" which will be available from Cingular. The video below from Mobilytsite compares download speeds of HSDPA (Cingular), EVDO (Sprint) and EDGE (Cingular).

As you can see in the video, the download speed is faster than what I can get over my 1 MBit/s ADSL line at home. Amazing! The other plus of the device is the built in EDGE (Enhanced Data Rates for GSM Evolution) support so the smartphone is also usable in areas with no 3.5G coverage without being crippled by low GPRS speeds. With these and other phones surely in the pipeline of Samsung and other companies, it looks like we could soon see some real traffic in the UMTS networks in the US which so far have not been used much due to a lack of market adapted handsets. Great! Now let’s work on dual frequency UMTS handsets for international roaming!

Background for the story via the 3G Portal, Moveable Beast and Mobilitysite

It was back in February this year when I first met Stuart Mudie, co-author together with Derek Torres of  The Unofficial Guide to Windows Vista in Barcelona during the 3GSMWorldCongress. Since then, we’ve met a couple of times again in Paris and it was quite interesting to exchange thoughts on how our book projects were advancing. So it looks like his book will be available shortly and I have gladly agreed to host the Unofficial Guide to Windows Vista blog tour for an entry on Vista’s Wifi capabilities. Over to Derek:

First, I’d like to thank Martin for being a gracious host  and letting me spend some time discussing Wi-Fi capabilities in the new Windows Vista. Let’s take a look at the basics!
   

It’s easy to make the case that Windows Vista is all about  wireless. Instead of having to waste time with Network Connections like in  Windows XP, you can handle most of your Wi-Fi configuration through the new Network Center in Windows Vista.

Let’s be honest; during the Beta phase of Windows Vista,  Wi-Fi was absolutely atrocious. Neither Stuart or I were able to connect over a  wireless connection and were confined to the length of our network cables. That’s  not totally unexpected, after all, this was Beta. By the later stages of Vista  development, Microsoft was on the right path.   Using a USB wireless adapter (Netgear WG111T), Windows Vista immediately  recognized the software and installed all the necessary drivers without me  having to insert an installation CD. I was online in a matter of minutes.

What’s particularly interesting about Wi-Fi in Windows Vista is that it goes well beyond using your computer around the house or in the garden;  in fact, what’s most interesting about Wi-Fi is not how your computer can use  it, but what other components can use it!

If you’ve got an Xbox 360 or a digital media receiver, you can use those with Windows Vista over a wireless (or wired if need be)  connection. Instead of enjoying your laptop anywhere in your house, you can use  your Xbox 360 to broadcast media – including music, movies, and pictures – from  your computer to another room in the house. You can also use it to enjoy  digital music across the house using Windows Vista’s Wi-Fi capabilities.

Windows Vista certainly helped up the ante in terms of Wi-Fi  capabilities; not only is Wi-Fi more and more exciting, but it’s definitely more useful!

Derek Torres, co-author of the Unofficial Guide  to Windows Vista
   

 

One of the many new things I relish about the Nokia N93 is that it let’s me download podcasts with the podcast catcher application directly to the phone via Wifi. Previously I had to download podcasts to the PC first and then had to sideload them to the phone either via the USB cable or by putting the phone’s memory card into the card reader on my PC.

Things are much simpler now: New podcast feeds can be discovered in the application via the search function, no PC needed. Should you stumble over a good podcast feed on the PC, you can also type in the feed’s URL in the unlikely case the search on the phone doesn’t find it. With a push of a button the application updates all bookmarked feeds and new podcasts can be selected and downloaded afterwards. I’ve got a 1 MBit/s DSL line at home and I was quite astonished that the phone is easily able to fully use the bandwidth.

While I’ve set applications like the web browser to always ask which network connection to use, I’ve set the podcast catcher to always use the Wireless LAN connection without asking. Downloading a 50 MB video podcast via 3G is of course possible, but somewhat expensive.

Here is my current list of podcasts I’ve subscribed to:

• The All About Symbian Podcast
• The All About Symbian Video Podcast
• The Smartphone Show
• Computer Club 2 (A German tech magazine!)
• The Voice of S60
• The French Pod Class (vraiment encroyable…)

Know of similar ones? Please let me know!

P.S.: Steven Stewart, product manager for the application recently gave an
interview to Phil of the Voice of S60. Here’s the link to the
podcast. Very insightful.

The recent Nokia World had a couple of very interesting keynote speeches which Jyri Engeström has summarized very nicely on his blog. Videos of the keynotes can be found here and the Nokia World blog can be found here.

Nokia’s Anssi Vanjoki has always interesting stories to tell. Some might think he’s talking about tomorrow when describing mobile usage scenarios. But in fact, it’s all possible today. Take my day as an example:

I got up, updated my private eMails on my N93 over Wifi at home, downloaded some podcasts to the phone to have something to listen to while on the way to the airport in the afternoon, side loaded some mobile transcoded TV shows I like from the PC to the phone to additionally have something to watch. Finally before leaving the house I updated my weather forecast widget and my blog roll on the phone over Wifi and my DSL line. On the way I "consumed" most of the content while sitting in a train and also jumped right into very interesting articles in my blogroll while listening to some music from my collection on the phone. Every now and then, I followed a link in one of the blog entries with the phones web browser over the 3G network to get some background information on a topic. While waiting at the airport I also checked some news web sites to see what’s going on outside the cyber space. After so much consumption it’s good to be a bit productive as well and so I answered some of those eMails which have accumulated over the week. A foldable keyboard for quick typing is a real helper for this. Arriving in Paris I checked my eMails again over the wireless network while sitting in the suburban train and arriving at my destination I downloaded the latest news videocast of my favourite TV station over Wifi to the phone to watch the news while having dinner.

And then there’s the new bed I ordered online at Ikea tonight. But I have to admit that I didn’t do that on the phone but used the PC for a change…

P.S.: And yes, I made two phone calls with the phone multimedia computer while traveling. When arriving at my destination in Paris I used a dedicated wireless VoIP SIP phone to call back to Germany. The N93 has a SIP stack but as of yet no SIP client that makes use of it. Hello Nokia, here’s your chance to complete my experience.

And here’s a flash message on very short notice: It looks like December 4th will see the first Mobile Monday in Germany. The inaugural session will take place in Düsseldorf. One of the founders seems to be Russell Buckley who writes over at Mobhappy. Strange, I read nothing about it on his blog or elsewhere until I stumbled over it today. They’ve got a very interesting speaker lineup for the first session including Russell and Ajit Jaokar, fellow book author and blogger over at the OpenGardens blog. So spread the word and go if you can still do it on such short notice, it is going to be great! Unfortunately for me, I’ll be in Paris on Monday and won’t be able to come.

Got an N93 or other N-series phone and like to convert your videos and TV recordings for mobile viewing? It seems it is simpler than I initially thought. Take a look at the free MediaCoder for Windows which converts just about any video format into what’s required for mobile. Converting a file is as simple as selecting the input file and hitting the start button in the application.

Converting videos for the N93 works just perfectly with the default settings in the program for the iPod video format. The N70 has it’s own setting as it doesn’t seem to support the 25 frames per second and high encoding rate of the N93 and iPod.

I made a first test by converting a WMV coded one hour TV show I recorded via an online video recorder into mpeg4. Input file size: 387MB. Output file size: about 200MB. Good that I’ve got that 2GB flash card in my phone… Video quality on the N93 is excellent, even the smallest details and texts can still be read on the screen. Conversion time for the one hour show was about thirty minutes on my 1.9 GHz Centrino notebook. Final test step: I’ve played the recording on the N93 and detected no problems, no glitches, no crashed. Excellent!

Several years after the start of 3G and some operators still
struggle with their 3G network engineering. Unbelievable but true.

Latest
example: Wind in Milano, Italy. I’ve been using the Wind network already last
year in Roma for several weeks and enjoyed great 3G coverage and performance. A year
later, I am in Milano, a city in Northern Italy, and the situation is
completely different. Last week when I was here the 3G network was completely
unusable, due to packet drop rates of 30% or more. This week the situation has
improved but it still is nowhere where it should be.

Over the weekend I had some time to take a closer look what was
going on. While at first I suspected that they had some timer and threshold
problems that makes the connection switch between dedicated and common
channels, I quickly saw that this was not the case. Instead, there is frequent
measurement control messaging, traffic channel reconfiguration and active
setup updates. Every time the channel is reconfigured, packets are either lost
or delayed for a second or two which slows down the connection considerably.
After a while this starts a chain reaction as sometimes web page downloads
become so slow that the network decides to switch the connection onto a common
channel. This again provokes packet delays. It doesn’t seem to be a single
mobile issue as it happens with three different phones. Very strange as I am in
a place with excellent network coverage. So Wind, please get out there and fix
this!

But then, Wind’s also got EDGE coverage in Milano, which
works very well… Shame I have to fall back on 2.5G because their 3G network
engineering is flawed…

Let’s timewarp to 2012. I am in a small foreign town somewhere out in the countryside. I want to check my eMails and browse the net a bit. What kind of wireless access will I find in that place five years from now? 3G? Hopefully. Wifi? Well could also be, but at what price? Or even WiMAX? Why not with Intel pushing the technology and promising to get chipsets out the door soon which can do both Wifi and Wimax (Rosedale 2?). Let’s stay with WiMAX for a second. How will my experience look like? I can imagine several scenarios:

The 3G-like scenario: I open my notebook and I detect a local WiMAX network. Unfortunately, just like most 3G networks today, access is restricted to users with a valid SIM card. No other way to access the network. Too bad for me, as I can’t use the network and too bad for the network operator as he is missing out on potential revenue.

The Hotspot-like scenario: Again, I open my notebook and detect a local WiMAX network. Local users have a SIM card just like with 3G and access is seamless. However,the network is clever and sees that I am a roamer without a SIM and permanent subscription. Thus, it allows me restricted access and guides me to a web page where I can buy some volume or time credit. Prices are moderate and I am only billed for the time or volume I really use. Excellent. Maybe the network is even clever enough to detect my device whenever I log on again afterwards. Instead of having to type in my credentials again, I am just shown a page which welcomes me and tells me that network access for the prices as agreed last time has been granted again without further ado.

But maybe 3G operators have learnt their lesson in the meantime and are now offering affordable roaming prices to access the Internet. No need for the WiMAX network then. I wonder if the WiMAX competition has helped in this change of mind or if new EU regulation gave the gentle push!?

The Smartphone Scenario: So will my smartphone in 5 years from now support 3G with fallback to GPRS/EDGE for the really remote parts of this world, Wifi for home, and WiMAX (because 3G operators still won’t allow me to roam abroad and connect to the Internet at a reasonable price)?

I think we won’t see a several network technology everywhere world by 2012 so I hope WiMAX networks will be as open and reasonably priced as possible and devices to have enough wireless technologies built in to allow true roaming worldwide.

As bizare as it sounds but I think only a healty competition of different wireless technologies and mindsets will ensure the best possible network coverage for each technology.

Other Ideas? Anyone?

I was not sure if I should post my “TFO and
TrFO introduction” here as there are probably only a handful of people on the
globe who are interested in this topic. Also, some prior knowledge is
required on how GSM and UMTS networks handle circuit switched calls and how
things change with the introduction of 3GPP Release 4 BICN functionality. A
good intro on this topic can for example be found in my book (take a look on
the left). Most of my blog entries require no such in-depth prior knowledge but
this one definitely does. I decided to do it anyway as I didn’t find any other
usable overview on the web.

Tandem Free Operation (TFO) and Transcoding
Free Operation (TrFO) Overview

Voice calls from mobile phones today always involve several voice transcoding steps
in GSM and UMTS Release 99 networks. This is done mainly to transport a voice
call, which uses sophisticated compression in the radio network, through the
core network with the standard G.711 PCM (Pulse Code Modulated) codec over 64
kbit/s circuit switched links. Furthermore, transcoding a voice data stream to the
64 kbit/s G.711 PCM codec is necessary in order to call fixed line phones.
Another advantage of voice transcoding in the network is to be able to process
the voice data stream and to compensate for unwanted effects such as echo in
the speech path.

With the introduction
of the Bearer Independent Core Network functionality in the 3GPP Release 4
standards, core network connections are based on high bandwidth ATM or IP links
rather than on 64 kbit/s TDM links. In such networks it is therefore possible
to transmit a voice data stream in the core network with other codecs than 64 kbit/s G.711. This
also has the additional benefit of removing transcoders from the speech path which
reduces speech path delay and improves speech quality to some degree as the
speech signal is no longer degraded by the transcoding process. Furthermore,
not having to convert to the narrow voice band G.711 codec allows the use of
AMR Wideband (AMR-WB) codecs. These codecs are not backwards compatible to
G.711 without loosing their much better audio quality which they achieve by
encoding twice the frequency range as previous Full Rate, Enhanced Full Rate,
AMR and G.711 codecs. A general downside of not using a transcoder in the
network is that it is no longer possible to process the voice data stream to
remove effects such as echo.

Transcoder Free Operation (TrFO)

In UMTS
Bearer Independent Core Networks (BICN), PCM links which require the use of the
G.711 codec are no longer used. Instead, connections to RNCs in the radio
network and connections to other Media Gateways are based on ATM and IP.
Therefore, the MSC servers involved in a call can establish a bearer path
without activating voice transcoders in the media gateways between two mobile phones. For a mobile to landline call the connection remains transcoder free up to
the media gateway which connects the wireless network to the fixed network.
Here, the transcoder is used to convert the compressed audio signal to G.711.

In mobile
to mobile calls, both handsets report their codec capabilities to the MSC
servers involved in the call as part of the signaling before the bearer path is
established. Thus, an AMR-WB codec is automatically used if supported by both
terminals. This greatly improves the voice quality of the call. If not
supported on both ends, a standard narrow band AMR codec will be used for the
connection instead. This is called Transcoder Free Operation (TrFO) and the out
of band transcoder control performed by MSC servers is described in 3GPP TS
23.153.

While TrFO
works well while both ends of the connection remain in the UMTS network, it has
to be deactivated if one of the two parties is handed over to a GSM network
during the connection. This happens, for example, if the subscriber roams out
of the UMTS coverage area or in case the UMTS coverage is temporarily weakened
by obstacles while GSM network coverage remains acceptable. This can happen for
a number of reasons like because of different locations of the UMTS and GSM
base station sites or due to better GSM in-house coverage. If AMR-WB was used for the call, deactivating TrFO
also requires a fallback to AMR which results in an abrupt voice quality
degradation of the call in case the GSM network does not support Tandem Free
Operation which is described next (see also 3GPP 23.153, chapter 6.5).

To
communicate with services in the networks such as a voice mail system, or a
prepaid top up voice server, DTMF (Dual Tone Multiple Frequency) tones are used
to send passwords and commands to the system. If a call is established from a
UMTS terminal, DTMF tones are sent as out of band signaling messages to the MSC
Server. The MSC Server is then responsible to forward the message. If the
service platform which analyzes the DTMF tones is BICN compatible, the tone
is delivered as a message. If the service platform is still using PCM links and
the G.711 codec, the DTMF tone is inserted into the voice connection at the Media
Gateway at border to the PCM network. If a call is established from an external
PCM network to a service in BICN network, DTMF tones are not sent as messages
but inside the voice bearer. In this case, 3GPP 23.153, 5.9 requires the
gateway at the border of the BICN network to discover the inband DTMF tone,
remove it from the voice stream and send a DTMF signaling message to its MSC
Server which then forwards the DTMF message out of the voice band to the
destination.

Tandem Free Operation (TFO)

For GSM
networks, TrFO can not be used even if the core network uses BICN media
gateways and MSC-servers. This is because the A-Interface, which connects the media
gateway to the BSC/transcoding unit is based on PCM. Thus, voice calls from GSM
radio networks always arrive at the media gateway as a PCM G.711 64 kbit/s
circuit switched stream. Unlike in UMTS, where the transcoding is a
functionality of the media gateway, GSM uses a dedicated transcoding unit
between the BSC and the media gateway. This is necessary in order not to change
the radio network architecture when the core network is upgraded to BICN. As a
consequence, a mobile to mobile GSM call will always have two PCM links in the
connection, one to and from each transcoder and thus a GSM call is always
established using the G.711 codec. The two transcoders of the connection are
also called a tandem. In order to remove the transcoder tandem from such a connection,
in band codec negotiation between the two transcoders can be attempted once the
call is established. Instead of sending signaling messages via the MSC-servers
through the network, the two transcoder units send their information embedded
in the G.711 link. This is done by using a special bit pattern as part of the
voice stream which is recognized by the other end as a transcoding control message
and not as a part of the voice signal. If both transcoder units support at
least a single common codec like AMR 12.2 or an AMR-WB codec, the 64 kbit/s
G.711 connection is used to tunnel the compressed and encoded voice stream. As
the audio stream is compressed most of the bits of the transparent 64 kbit/s
stream are not used. This effectively removes the transcoder tandem from the
voice connection and is thus called Tandem Free Operation (see 3GPP TS 23.053
and 3GPP TS 28.062). While audio quality and delay times can be improved this
way, no bandwidth savings can be achieved in the core network unlike with TrFO.

Some events
in the network can temporarily interrupt TFO and the speech path in the core
network automatically falls back to standard G.711 encoding. This is the case
for handovers for example in which the call is handed over to a cell which is
controlled by a different TRAU. This is the case for an inter-BSC handover for
example. Once the handover is complete, TFO has to be negotiated again between
the two TRAUs (see 3GPP TS 23.053, 6.5.7). TFO is also temporarily interrupted
when the MSC inserts DTMF tones or announcements. As the MSC is not aware of
TFO it overwrites the compressed speech information in the circuit connection.
This is detected by the terminating transcoder and transcoding elements are
automatically reinserted into the speech path. Especially for AMR-WB, TFO has
to be started again as soon as possible in order to avoid speech quality
degradation.

Conference
bridges are another network feature which automatically disable TFO. This is
because standard conference bridges mix G.711 voice signals from several
parties to produce a combined signal which also overwrites the TFO data stream.
This again forces the TRAUs to introduce a transcoder in the speech path again.
While this has little impact on narrow band speech calls from a voice quality
perspective, it is not possible to use AMR-WB when a conference bridge is
inserted unless the conference bridge also supports TFO and the AMR-WB codec.

There we go, if you have made it up to here, please consider leaving a comment 🙂