Category: Uncategorized

It’s good to see Nokia presenting two new Nseries models yesterday. While I leave it to others to report on all the multimedia details, I was intrigued that both devices support several UMTS frequency bands, a first for Nseries devices.

The N85 has the most wide ranging UMTS band support. According to the datasheet, there will be two versions: The first one supports UMTS in the 900/1900/2100 MHz and is thus clearly targeted at Europe and the starting deployments of UMTS in the 900 MHz band in addition to the 2100 MHz band. The 1900 MHz band is at least partly usable in the US, where AT&T has deployed UMTS in some cities. The second version supports 850/1900/2100 and is probably mainly targeted at the US since AT&T uses both frequencies. Too bad it doesn’t support all four bands, it would make a great world band phone that way.

But despite the support of three UMTS bands there are some combinations which don’t work so well: For Australia, both models are needed since Telstra uses the 850 MHz band for 3G and Optus deploys 3G in the 900 and 2100 MHz bands. So should both operators sell the phone in the future they will each sell a different version.

Some people in Europe might actaully prefer the US version of the phone as there are only few places where 3G is deployed in the 900 MHz band yet and they might thus benefit more from the 850 MHz band when roaming in the US (e.g. with an AT&T prepaid card for Internet access). Bizare… Also interesting is that T-Mobile US won’t be able to sell the phone since it doesn’t support the AWS 1700/2100 MHz band.

The N79 seems to support 900/2100 MHz for now, so clearly targeted at Euope and potentially Optus in Australia. I wouldn’t be surprised though to see a 850/2100 MHz version soon.

Well done, Nokia, it was really time to add multi band 3G suport to Nseries, especially for roamers like me!

The Carnival of the Mobilists is back for a week where it all started, at Russel Buckley's and Carlo Longino's MobHappy. It seems a lot of people have come back home from vacation as this weeks Carnival is filled even more than usual with lots of great links to wireless insight. So don't hesitate, head over and enjoy!

Teltarif reported recently that O2 Germany have now configured their packet core to accept any kind of Access Point Name (APN) configuration of the mobile to activate a default Internet connection. According to O2 this will make it easier for customers to use the mobile Internet as configuring the mobile is simplified.

However, the article also mentions the bad side of this move: In the past, a non- or wrongly configured APN prevented accidental use. Now if the user forgets to lock his mobile before tugging it away in his pocket and that "@" key gets pressed, O2 happily starts charging. It already happened to me a couple of times under different circumstances. Especially nice when you are abroad…

So despite their probably good intentions I am a bit sceptical that this is a good move for consumers. From my point of view it's not the APN configuration that keeps people from trying the mobile Internet but the inadequate standard pricing many operators still have in place.

This week, the Carnival of the Mobilists is hosted by Debi Jones over at mobilejones. A post not to miss since Debi does a great job of covering all the latest news, thoughts and ideas around mobile and the Internet of the past week. So, head over and enjoy!

In a recent press conference, Vodafone UK gave some numbers concerning the use of their 3G network. According to them, 50% of the data traffic is handled by only 10% of the cells. As I don't know what was said around that statement I wonder if they see this as good or bad!?

I can see several conclusions to draw from this statement:

I guess mobile operators would prefer a uniform traffic distribution in their network, both in space and time. But it doesn't even happen for voice calls as traffic is much higher in cities compared to the countryside and highly varies throughout the day. That's why operators use high capacity cells and increase base station density in cities.

So if most of the traffic is occuring in only few cells it could be good for Vodafone because they only need to upgrade those cells for higher data capacity on the air interface and the backhaul while while leaving the rest of their network as it is. And if that is not enough in high use areas additional base stations could be put in place, but again only in certain areas.That is simpler and maybe also cheapter than to densify the network throughout the country because traffic distribution is uniform.

On the negative side it could of course also mean that they can't keep up in the future adding capacity fast enough. For the moment, I hear that Vodafone's network is still doing fine, even in densly populated areas.

So if you are reading this and have some more background information or want to share your own thoughts around this statement, please consider leaving a comment.

Another week, another Carnival! This week, the Carnival of the Mobilists is hosted by AllAboutIphone.net by Matt Radford. As always, a great compilation of what happened in the mobile blog sphere in the previous 7 days. So don't wait, head over and enjoy!

Do you know Ajit Jaokar and Michael Mace? If not I suggest to head over and check out their blogs (here and here) for great insight into the mobile domain. Or, even better, use the opportunity to meet them in person on the 8th of September at the University of Berkeley, California at the Mobile Web Megatrends Conference on September 8th, 2008. Topics of the conference range from mobile browser evolution, browser offline capabilites, advertising models, the iPhone (of course…), mass market impact with Nokia's S40 6th edition, cloud computing, etc. etc.

Lots of other great speakers, I let the conference's web site speak for itself.

Definitely a conference not to miss if you can make it. Unfortunately my calender is already booked for that date so I won't be able to make it. But good for you since I have one free ticket to give away! First come first served.

In the fixed line world, the basic Session Initiation Protocol (SIP) has become quite popular for offering voice telephony service. Lots of companies such as Vonage, Siptel and DSL providers are making use of it today. So why are we not using SIP in 3.5G and 4G networks as well? I guess there are both policital and technical answers to this question. From a technical point of view there are a few features missing that are essential in wireless networks:

– Voice codecs: Current SIP implementations usually use G.711 voice encoding which produces a 64 kbit/s data stream. Transported over IP the total bandwith requirement per direction is 80 kbit/s. Compared to the effient codecs used in wireless networks today such as 12.2 kbit/s AMR with a similar voice quality this is quite a lot and significantly reduces the number of simultaneous voice calls per cell. The current voice architecture uses a transcoder between the radio network and the core network to restore G.711 compatability. So from a capacity point of view, using G.711 in the radio network is probably not a good idea and would meet the resentment of most operators. So from my point of view we need AMR capable mobile SIP clients and transcoders in the network to reach non AMR capabale (fixed) SIP clients and circuit switched networks. Note that such transcoders are already present in the SIP networks today, usually as media gateways between the SIP world and the classic circuit switched world to which most people are still connected to with their fixed line and mobile phones.

– We need to get rid of NAT and STUN: Most mobile operators use private IP addresses for their customers. This requires Network Address Translation (NAT) which in turn unfortunately requires frequent polling packets to the SIP and STUN (Simple Traversal of UDP through NAT) server. These packets keep the connection to the network open continuously but drain the battery of a mobile device very quickly. The solution to this issue is to use public IP addresses and to ensure that keep alive messages are removed from the SIP implementation as much as possible. With the lack of sufficient public IPv4 addresses this will require IPv6 at some point.

– End to End – Encryption: All SIP clients I use today do not encrypt signalling or the voice call itself. With freely available tools such as Wireshark, calls can easily be traced and recorded. While circuit switched networks are reasonably secured it is difficult to ensure there are no unwanted listeners in the route in public IP networks.

– The missing link: Handover to 2G circuit switched connections when running out of coverage. This one is very difficult to do. Sure there is VCC (Voice Call Countinuity) for IMS but the complexity both in the network and the mobile device is significant. I have to admit I have no easy solution for that.

Are there other essential SIP extensions that you, fellow readers, can think of to enable SIP for mobile networks without going to a full blown IMS implementation?

Good news on the Wi-Fi front: Linksys has launched the WRT610N access point, which simultaneously operates in the 2.4 GHz band for current 802.11b/g devices and in the 5 GHz band for new 802.11n devices that support the so far little used frequency band. Should make the transition to the new frequency band much easier, especially if more vendors do the same in the future and integrate it with DSL modems!

From a technical point of view it's interesting to note that the data sheet says each band has it's own set of three antennas (I guess to support MIMO).

In a report I read today I learnt that WIPI (Wireless Internet Platform for Interoperability), a mobile device runtime environment for applications similar to BREW and JAVA, is mandated by the Korean government to be included on any mobile phone sold in Korea that allows Internet access.

An interesting way to prevent companies such as Nokia, SE, Apple and others to sell their devices in Korea. In the past there were only CDMA based 3G networks available in Korea so this technology dispute was mainly between Korea and the US (hello Qualcomm…). As some Korean operators have now transitioned from CDMA to UMTS the issue now gains a more global dimension.

While these UMTS networks now theoretically enable Nokia, Sony Ericsson, Apple and others to sell their devices in Korea, the WIPI ruling prevents that from happening. But it looks like some operators have become rather unhappy and are asking for lifting the WIPI ruling. Lots of questions poping up here:

• I wonder if there is a black market in Korea for such phones today?
• Not sure if such phones would even be desired at the moment due to the probably missing Korean language integration and also due to the sophistication of LG/Samsung phones.
• Also, I wonder how widely WIPI is used at the moment, is it seen as an integral part by a large user base?
• In case the application environment is very popular I wonder if lifting the WIPI ruling would have an immediate effect if people would not buy devices without it.

Fellow readers in Korea, what do you think?