S60, Python, a GPS receiver, and Google Earth

Now that most work for the book is done, I have some time to experiment. I recently started to take a closer look at Python for the S60 mobile phone OS and what you can do with it. As I am pretty much into wireless networks, I wanted to have an application that tracks the network coverage where I go for later analysis. I am also quite interested in location based services and a firm believer that these services will only really take off once the GPS receiver is built into the phone. Combining these two interests with a little bit of programming and a recently bought Nokia LD-3W Bluetooth GPS receiver resulted in the following little quality time project:

The Python script I am currently working on queries the GPS receiver, measures the network signal quality and outputs the information in Google Earth format for visualization on the PC. The script is not quite finished yet but the  basic functionality of logging location and signal quality and visualize the data in Google Earth already works. The picture on the left (click to enlarge) shows a result of a 20 minutes test drive. While the line is green, network reception is good. Blue indicates average and red symbolizes a weak signal. Should you be one of the five people on this planet who does similar things and are interested in the source, let me know.

Mobile Monday Paris May 2006 – Pictures and Thoughts

Another Mobile Monday Paris took place last night at the Zen Factory in Paris close to the Place de la République. Again a fabulous event, lots of good discussions with people coming to the event and very interesting presentations. For pictures of the event, see my Flickr picture set of the evening.

First speaker of the evening was Stephane Delbecque of Yahoo France presenting Yahoo’s Connected Life vision. Focus of the presentation was Yahoo’s partnering with the Fifa to bring the football world championship to mobile phones all around the world.

Next, Didier Lesteven of Medialive presented their product which protects digital content on the way from the content provider to the consumer. This is done by their product by stripping out 1% of a media flow which is then protected and sent to the consumer in a secure way.

Afterward Philippe Coup-Jambet of Mobitype gave an overview of their moblogging platform that lets you create your own blog from your mobile phone and also acts as a mobile RSS aggregator. The product is currently in a first trial phase with the public launch expected this summer. The service will be free and is funded by ads which are put into the generated pages. I specifically liked the options of having the top 24h hour posts in one menu as that is missing in my current mobile RSS software.

Presentation number four was by Vincent Berge of the PACA Mobile Center, a new parisian institution in Marseilles that offers a platform for Java developers to test their products on a multitude of different phones.

And finally, Catherine Ramus made sure the evening was not only about technology in itself but also about combining technology with art and her presentation was about how to use 2D bar codes in a museum to get video stream art right on your mobile phone.

Great presentations, thanks very much to the presenters, I really enjoyed the evening! The presentations might end up on the official Mobile Monday France website in a couple of days and you can check them out here.

The Mobile Internet’s 5th birthday

T39j Only 5 years ago, the Internet started to get mobile for me with the launch of the first GPRS networks in Germany and the advent of the first GPRS capable phones. What a different world it was compared to today.

I must have been one of the first GPRS users of the network because at this time and phones and networks were in a shaky beta phase at best. The Ericsson T-39 (first picture on the left) was my first GPRS phone. Equipped with a tiny monochrome display, it could bundle two timeslots to give me a blazing download speed of 25 kbit/s. For web browsing I used a Palm III, also with a monochrome display and one of the first embedded web browsers available at the time. Again, pretty much a beta experience but I loved it.

Yesterday, 5 years later, I was sitting in one of Paris’ best cafés, enjoying good company, an ice cream and discussing mobile lifestyle: Instead of bringing a magazine with me to browse through, my Nokia N70 is always with me ready to take pictures, videos and to connect me to people and the Internet. Here I was, reading the latest news using the Opera browser on the phone, when my eMail client informs me of a new eMail of my publisher in which he informs me that the shipping date for my next book will be July 14th. Great! A little while later, I uploaded some pictures in the background to Flickr which I took in the afternoon while reading some interesting blog entries in the mobile RSS reader at the same time. On the network side, UMTS is much more stable than GPRS was only 5 years ago and data rates have improved from the 25 kbit/s of 5 years ago to 384 kbit/s today.

So what are we in for in 5 years from now? Network speeds will certainly be beyond 8 MBit/s in downlink and 2-3 MBit/s in uplink direction. Prices for mobile data will (hopefully) be at a level to attract the general audience and in combination with the increased bandwidth and services such as video up- and download, LDA applications using the Internet connection and built in GPS receivers will make the application landscape even richer.

The football worldcup – coming to a mobile near you

Not that I am the greatest football fan of all times but a recent entry in Christian’s blog has caught my interest: Yahoo has launched a mobile version of their football world cup coverage site and seems to be the official partner of the Fifa. Check it out at the Fifa web page. There’s a link leading to information how to access the mobile site in the middle of their home page. For those of you not living in one of the countries where they offer a free SMS with the link, point your mobile browser to http://www.fifa.com/e/wc.

There’s lots of content on the mobile site already and you can register for sweets like free SMS alerts on goals when your favourite team is playing. Looks like Yahoo sees this as a good opportunity to get people interested in the mobile web and of course what Yahoo is doing in this domain. With all the media hype around the world cup and people being so excited I tend to agree.

I haven’t seen too many mobile offerings for the last Winter Olympics (but I have to admit I didn’t really look for them). So is this the first time such a world wide event also get’s some world wide and free (to what an extend we will see) coverage on the mobile web? I wished there was a similar offer to keep track of what’s going on in Formula 1.

So here we are right in the battle between content providers such as Yahoo and mobile operators to get the attention of mobile users. Let’s see who does a better job. I’ve quickly checked if my home operator (Vodafone Germany) is offering anything similar and how it compares. Looks like they also offer free Goal alerts via SMS but beyond that I didn’t see much. Let’s see how it develops.

Global GSM and European UMTS Rollout Progress

While having visited a colleague in his office yesterday I saw an interesting global map on the wall showing the current global GSM rollout status. The map was different from all other maps I’ve previously seen as countries which adopted GSM technology were not completely filled with a color marking them as "covered". Instead, the map showed the detailed coverage status in each country. The map together with even more detailed continental maps can be found at www.coveragemaps.com.

Here are some of my personal observations which quite surprised me:

The U.S.: When I last checked two or three years ago, GSM coverage in the U.S. was patchy at best. I still remember checking on Texas and finding an almost empty map. Quite a different picture now.

South America: Except for the rain forests, the continent is well covered with GSM now.

3G Rollout in Europe: The map gives quite a mixed picture varying from country to country. While the UMTS rollout seems to be quite advanced in some countries, there are lots of ‘GSM’ only areas in other countries:

Germany, U.K., Ireland, Sweden, Austria: These countries seem to be pretty well covered with 3G already. I can confirm this for Germany at least where Vodafone has dedicated coverage even in small villages (<5000 people). Nevertheless, it’s still patchy on the countryside. Same goes for Austria.

France: Quite disappointing, the green "GSM only" areas are still substantial. The map seems to be quite accurate as it compares quite well to the official map of Orange, France that can be found here.

Italy: This one is strange, only a couple of yellow "UMTS" patches here and there. But I don’t think the data is up to date in this case as Italy was one of the first countries deploying UMTS and the current Wikipedia entry on Vodafone Italy says that 70% of the population are now covered by UMTS. I tried to find coverage maps on tim.it and vodafone.it but it didn’t find any. Is my Italian so bad? If somebody sees maps, please tell me. The only info I found was on tim.it. On this page you can select you city and a database lookup reveals if there is coverage or not. No maps though… However, many cities I tried which were not covered on the map came back as UMTS covered.

Finland: Another strange case. The land of Nokia, the land of mobile phones and almost no UMTS areas on the map!? Can this really be!? Some of my Finnish readers, please check and comment. A link to a coverage map of a Finnish operator would also be nice…

Offshore: Also take a closer look at the GSM coverage spots in the North sea. They seem to be drilling platforms! Cool!

How the Nokia N80 handles WLAN

Up until now not much is known about how applications on the N80 will be able to use the built in wireless LAN capabilities. When checking the Nokia website today, I saw that the N80 manual can now be downloaded from this link. So I rushed to take a closer look to see if it sheds some light on this topic. And indeed it does!

Basically, the manual says that the use of WLAN is transparent for an application on the phone. Just like for a data connection via GPRS and UMTS, a new access point profile can be created to enter the settings of how to communicate via a WLAN network. Several profiles can be created if different WLAN networks are used, e.g. at home, at work and in public. In an application, a WLAN profile is selected from the already known list of access points that pops up when an application wants to access the network and no default access point has been configured in the application. Instead of only GPRS and UMTS connections the list can now also contain WLAN connections. Quite elegant, it’s completely transparent!

The manual also says that one access point profile can be used by several applications simultaneously. Again, this already works today for GPRS and UMTS connections when two programs such as the browser and the eMail program are used to communicate with the network at the same time.

And here comes the most important part concerning the simultaneous use of the phone in the GSM/UMTS network and WLAN. I quote from the manual on page 14: "You can use wireless LAN during a voice call or when packet data is active". That’s really great news and means that while at home, for example, the phone can be used for incoming (and outgoing) cellular calls simultaneously with an activated VoIP client (SIP, Skype…) via wireless lan.

It looks like my dream of a unified phone at home is close to becoming a reality! I can hardly wait using the Skype client on the phone to call friends while lying on the couch while not missing incoming cellular calls. Hurry up, Skype! Oh, and by the way, don’t forget to support the built in camera 🙂

SIP Update 1: Jukka left a comment that there’s already a built in SIP client in the N80. I completely missed that when browsing for the wireless LAN details in the manual. Indeed, the manual shortly describes that there’s a new menu where to enter the settings for the SIP client and that SIP addresses can now be part of a phone book entry. Would be interesting what can be configured but the manual doesn’t say. So Skype’s got another reason for hurrying up, the competition is already there!

SIP Update 2: The topic keeps developing: Too bad I don’t have an N80 yet so I have to rely on the sparse technical information in the manual. After some more digging I found out that the included SIP client seems to be closely tied into the standard voice call feature. The SIP functionality can be used during a standard voice call to establish a video sharing session via SIP in a packet bearer. While the feature is quite nice it’s not yet what I need to call someboday via VoIP over the WLAN functionality while being at home.

SIP Update 3: A reader has noticed that Nokia is about to release a major software update for the N80 called the N80i, or Internet Edition, whith some additional VoIP capabilities: From the press release: "The VoIP framework (based on the SIP protocol) is integrated into the
Nokia user interface, and the Nokia N80 Internet Edition is allows for
downloading compatible third party internet call applications.". One step closer but we still need a 3rd party client.

Communication Systems for the Mobile Information Society: It’s Almost Ready

I am always amazed of how much fine tuning goes into the production of a book. I delivered the manuscript at the end of January and since then it has been proof-read, the layout has been done and I’ve received the page proofs for final verification. Almost ready for production now. This weekend I’ve sent the final corrections of the page proofs back to the company that does the layout. For those of you who are curious, the book is already listed at Amazon and the listing contains the back cover text which gives some details about the content. Their publishing date of September is a little bit conservative… It should be out much sooner. I’ll keep you posted.

Vodafone 3G Rollout Progress


It’s interesting to see how Vodafone in Germany continues with their 3G rollout. Last year in May I went to their website and took a snapshot of their coverage map of south western Germany. As you can see on picture one, most areas are blue (GSM coverage) with some areas red (UMTS coverage). One year later (April 2006) I’ve taken another snapshot of their coverage map which is shown in the second picture. The red areas representing UMTS coverage have increased by quite a bit. Even small towns with less than 2000 people are now very well covered. Let’s see how it looks like in a year from now.

Bluetooth Q&A

All answers have been held as short as possible and require an understanding and study of the corresponding chapter of the book.

Answer 1:
Bluetooth transfer speeds depend on how many users exchange data in a Piconet, how much data is exchanged by the individual users at a certain time and what kind of multislot packets are used. In the ideal scenario with only two devices in which only one device has a lot of data to send, a peak data rate of 723 kbit/s can be achieved for one of the two devices.

Answer 2:
FHSS (Frequency Hopping Spread Spectrum) sends each packet on a different channel (frequency). This avoids using the same channel for a prolonged amount of time which might already be in use by another network such as a Wireless LAN. FHSS also simplifies device configuration as no channel number has to be selected by the user in the Bluetooth settings. Bluetooth 1.2 introduces adaptive frequency hopping which avoids channels with high error rates caused by parallel transmissions from other networks. This reduces transmission errors and the influence on other networks in the same area while at the same time increasing the overall transmission speed.

Answer 3:
The Inquiry procedure is invoked to search for unknown Bluetooth devices in the area. If a Bluetooth device is visible to other devices it responds to an inquiry packet it detects by sending its device ID. A paging on the other hand is used to directly establish contact with a Bluetooth device which is already known. If a Bluetooth device only wants to be accessible for devices with which it has previously communicated with, it only responds to paging messages and never to inquiries.

Answer 4:
Bluetooth offers a number of power saving mechanisms and states: Connection hold: A device deactivates its transceiver for a certain time. Connection sniff: A device deactivates its transceiver for a certain time but checks at predefined times if the master device wants to resume communication. If not, the device automatically returns to the power save state. Connection park: The devices releases its device address and uses a very long timeout value before checking again if the master device would like to reestablish contact.

Answer 5:
The link manager has the following tasks: Establishment of an ACL, SCO or eSCO connection, configuration of the connection, activation of the enhanced data rate mode, execution of a master-slave roll change procedure, pairing, authentication and ciphering management, adaptive frequency hopping management, and activation of different power save modes when appropriate.

Answer 6:
The L2CAP layer’s protocol service multiplexer is used during connection establishment to select to which of several higher protocol layers to connect to. In addition, an individual connection ID is used on the L2CAP layer for each connection to identify packets. This allows two devices to establish several simultaneous connections between each other for different higher layer applications.

Answer 7:
The service discovery database contains information about all services offered by a Bluetooth device. Other devices can query this database during connection establishment to detect which services are offered and how certain parameters have to be set in order to access them.

Answer 8:
Each Bluetooth profile using the RFCOMM layer has to register with the Service Discovery database. If a remote device wants to use the service offered by the profile it has to query the database in order to retrieve the RFCOMM channel number which has been assigned to this profile. As the number is dynamically allocated the database has to be queried for every new connection.

Answer 9:
Authentication: Two Bluetooth devices are able to authenticate each other if they have previously been paired.
Authorization: This is a security mechanism on the application level and allows to restrict access to applications to certain remote devices. This way it can be ensured that only some of the previously authenticated devices can access certain services. It might be desirable for example that only the notebook of a user can use the dial up connection profile of a phone. Other devices are barred from this profile but are allowed to transfer files from and to the mobile phone.

Answer 10:
Bluetooth is a very versatile communication technology that can be used for a wide variety of different services. This ranges from services like exchange of electronic business cards and images to connecting headsets, mice and keyboards to PCs and tablets. The Bluetooth standard defines a number of profiles to ensure interoperability on the application level. A profile specifies how a service is supposed to work and in which way remote devices can communicate with it.

Answer 11:
The object exchange (OBEX) profile has been designed for a fast and simple transmission of files and objects between two Bluetooth devices. The OBEX profile is the basis for the file transfer profile, the object push profile and the synchronization profile.

Answer 12:
When using the hands-free profile, the hands-free set is only seen as a microphone and loudspeaker extension of the mobile phone. The connection to the network continues to be established by the mobile phone. The SIM access profile does just the opposite. With this profile, the mobile station is only used as a SIM card reader. All other functionalities including the GSM/UMTS transceiver are deactivated. The hands free set then uses the Bluetooth connection to access the SIM card and can perform all transactions between itself and the SIM card just as if the SIM card was directly inserted into the hands free-set. Such hands-free sets are more expensive than those just using the hands-free profile, as they have to contain a complete mobile phone unit including the GSM/UMTS module. This has the advantage, however, that an external antenna can be used. Furthermore, the mobile phone can be configured for the use of both the SIM access profile and the headset profile. While the mobile phone is used in the car, the hands-free set takes over. Once the user leaves the car and takes the mobile phone with him, incoming calls can automatically be redirected to the Bluetooth headset once again. This can not be done as easily with a hands free set in the car supporting the hands-free profile as the phone is unable to decide for incoming calls to which device to establish contact.

Answer 13 (2nd edition):
Removed, no longer relevant.

Answer 13 (3nd edition):
There are significant differences of classic Bluetooth and BLE on the air interface. While BT uses fast frequency hopping and 1 Mhz channels, BLE splits the 2.4 GHz ISM band into 40 channels of 2 MHz each and uses very slow frequency hopping. BLE only uses GFSK modulation and the datarate is not variable but fixed at 1 Mbit/s over a channel. This reduces the datarate to a few tens of kilobytes per second but in return significantly reduces power consumption.

Answer 14:
The aim in BLE is not to establish a transparent channel between two devices but to transfer small amounts of data as power efficiently as possible. Therefore data is transmitted in a way that could be compared to reading and writing variables on a remote system.