Author: Martin

I enjoy surfing the mobile web with my phone while traveling. While I’ve bookmarked an assorted number web pages to keep me entertained and informed on the go, I’d also like to read the latest entries of the blogs in my blogroll. Most of us read blogs using an RSS aggregator, as surfing from one blog to the next with a web browser is not convenient when monitoring more then just a few.  On the mobile phone it should basically be the same as the process is even more difficult due to the limited bandwidth, the processing power of the mobile, the small keyboard, and especially the small screen size.

While searching for the right solution for me, I’ve tried web based readers but found them too slow and too inflexible for my needs.  Then I’ve found Resco News, an RSS feed reader application for Symbian S60 phones such as my Nokia 6680. It works like a PC feed reader and it is possible to import an already existing blog roll from the PC as the program supports OPML file imports which many RSS readers can generate. New blog entries can be shown either by feed (which I prefer on the PC) or all feeds together in a time ordered list. I prefer this to the per feed view on the phone as it is much easier and faster to navigate through on a small device. As it downloads and stores the content of the xml files, I can even read the blogs while out of network coverage (yes, there are still many blind spots in the Paris metro…). I really like the program, and I am more than willing to pay the $12.- for the full version.

Of course, there is always room for improvement 🙂 I think that one of the shortcomings is the huge amount of data that is downloaded to the mobile during every update. I’ve chosen to synch about 35 blogs to the mobile phone which results in about 1 MB of data transfer for every synch. This is an issue both cost wise (if you don’t have a large data subscription) and time wise as well, as the update of all blogs takes around 5 to 6 minutes. This can surely be improved in a future version of the program by requesting several rss feeds at once instead of one after another. Another nice thing to have in the future would be a kind of rss proxy server that knows which parts of xml feeds have already been sent to the mobile device and only forwards those parts of the xml file which have not yet been received by the mobile phone. This would substantially reduce the amount of data to transfer. And then, a synchronization method with my PC RSS aggregator would be nice as well so I don’t see the same blogs as "unread" on the PC when I get home which I’ve already browsed through on the mobile.

If you know of other ways to read blogs on the mobile phone while on the go, let me know!

In part 2 on this topic, I’ll describe yet another blog reader application and discuss some more ideas on how to improve the experience further on the long term

Stuart Mudie is hosting this week’s Carnival of the Mobilists. If you are interested in the mobile Internet, it is the ressource to find out what people are thinking and in which direction the technology is moving. This week’s edition does not only contain a great summary of blogs written by mobilists in the past week but also some links to mobilist gatherings during the 3GSMWorldCongress in Barcelona next month.

The standard S60 notes program on my Nokia 6680 is just that, standard and just a little bit too basic for my needs. I don’t think the bar is set to high by wanting a notes application that lets me decide which name to give to a note, let me have more then a couple of hundred characters per note, have some basic cut/paste functionality and synch nicely to a PC.

I’ve surfed up and down the web to find a suitable program but came up pretty much empty handed. Sure, there is Quickoffice, which is just a little bit too much for what I need both in terms of functionality and price. The price would not even shy me away but the demo version refuses to run… SafeNote was another promising candidate. However, I haven’t been able to figure out how to copy the notes to my PC. Nice try.

Can it be that there is no notes application available that fulfills my three criteria above!? Comments welcome!

The multi media messaging service (MMS) is great to send pictures, videos and of course plain old text messages to other people. MMS is based on IP and the protocol is well standardized. If you ever wondered how MMS works or ever wanted to have your own MMS server at home (which puts your uploaded picture on a web page), here’s your chance:

http://heyman.info/

Jonatan Heyman has written an MMS PHP script during an internship at Ericsson which can be placed on any web server that supports PHP. Only a couple of configuration changes on the mobile phone are necessary and the MMS is sent to your own web server instead of to the MMS server of your operator:

• The URL of the MMS Server has to be changed to match the URL where the PHP script can be reached. The author has placed a demo script on his own website for those of you who are adventurous.  To upload a picture to his site, change your MMS Server URL to http://heyman.info/mms/get.php
• Most operators use different Access Point Names (APN) for MMS and transparent Internet access. To be able to reach the PHP script on the Internet, modify the APN settings in the phone to allow the MMS application transparent access to the Internet. The WAP or MMS APNs usually do not work as the network is usually configured to only allow access to certain services in the operator’s home network with them.

Further PHP scripts on the topic can also be found at http://www.hellkvist.org/software

While
checking out the eTel conference website to create a list for Debi (aka mobile
jones) of sessions that I am interested in, I’ve stumbled over an interesting
article of Matthew Gast analyzing just how many Voice over IP calls can be
squeezed through a Wireless Access Point. 22 to 23 is the answer 😉 In the
article, Matthew goes into the details of preambles, WLAN, IP, UDP and RTP
headers and shows how they influence the data rate and total number of
simultaneous calls. The article also
gives a brief overview of the voice codecs used by a number of voip systems
(including Skype!) and their required bandwidths.

I’ve subscribed to Audible a couple of months ago to download audio books instead of buying them from Amazon ,listening to them, and afterwards selling them on eBay. The only problem with their service is the DRM protection of the audio files. As there was no player available for Series 60 devices available that work with Audible, I had to burn the audio books on CD and  rip them from there into MP-3 format (I refuse to carry my 6680 and a MP-3 player!!!). Tiresome work, especially for 20 hour audio books which require 16 CDs. Nevertheless, I still prefer that to Amazon/eBay buying selling which also requires the MP3 ripping to put them on my mobile phone.

Now it seems Audible has recently launched ‘Audible Air‘ for Series 60 devices. Great application, it loads the audio books right over the network into the phone. However, you should have an unlimited data plan for this  (we are talking about 200 MB for a 20h audio book) whichi s unfortunately not yet offered for a reasonable price in Germany. So I was looking for a way to move the audio files from my PC to the phone and import it into the application as the link above mentions that this is possible. Zip, nada, nothing… The application just doesn’t want to recognize the files. On top, there is no manual for the application on Audible’s web site so I can’t even verify if I did something wrong.

So what’s the point in developing an S60 application that insists that it only wants to have the data over the air? It will be a nice feature in a year or two when unlimited data plans are a common thing… I am somewhat dissapointed.

Every now and then a ‘brilliant’ analyst claims that UMTS is just too slow and only a couple of users would be enough to fully load a cell. However, they usually never reveal how they come to this conclusion. So let’s set something straight here:

Data Rate

Only a few years ago, a per user bandwidth of 384 kbit/s over the air interface almost seemed like magic. Compared to DSL speeds today, it seems to be rather slow as entry level DSL usually starts at 1000 kbit/s today. For web surfing, the main application of most people today, there is only little difference between page download times of UMTS and DSL. For file downloads, a data rate of 40 kbytes/s can also not be called slow. Here, DSL undoubtedly has an advantage. Voice over IP (over UMTS) software such as Skype also works quite well. And, not to forget, networks are about to be upgraded to HSDPA which increases peak data rates to  2-3 MBit/s per user. Not quite here yet, but coming soon.

Users per Cell

The next myth often spread by analysts is the low number of subscribers that can be served by a cell. It is certainly true that only three users can be assigned a 384 kbit/s bearer simultaneously in order preserve some bandwidth for voice telephony and slower data connections.  If all three users would transfer a file simultaneously or stream a video, the cell would be fully loaded. However, not all users of a cell download data at the same time. Apart from “power users”, most subscribers use their Internet connection for web browsing and only seldom for downloading files or streaming audio or video content. This will surely change in the next couple of years, but the network continues to evolve as well with HSDPA and other future enhancements.

Voice over IP systems, such as Skype, will surely be used by more and more people in the future. However, the data rate generated by such applications is around 3 kByte/s in both uplink and downlink direction. This is much less than the 40 kBytes/s offered by UMTS today. Intelligent Radio Resource scheduling in the UMTS network can detect streaming at a lower rate than what is offered by the current channel, and can automatically reduce the amount of bandwidth dedicated to the user on the air interface. Thus, more bandwidth is available for other subscribers of the cell.

Let’s make a real life example

If I am working away from the office, I generate about 40 megabytes of traffic in about 10 hours. This includes eMail, web browsing, company database access and Voice over IP via Skype. 40 megabytes seems to be a huge number at first. The average data over time however is only 40.000 kbytes/s / 10h / 60 mintues / 60 seconds = 1.1 kbytes/s.  Compared to the theoretical bandwidth of a cell of about 1500 kbytes/s this is not a lot and about 1000 other subscribers with the same amount of traffic could use the same cell simultaneously. However, to go shopping with such a high number just as wrong as the claims by analysts that a cell is fully loaded with only 3 subscribers. So let’s refine the calculation by taking some real life factors into account:

Resource Handling: Once the network detects that a subscriber wants to transfer data, it usually assigns more bandwidth then required. During web browsing for example, the channel is seldom fully used. After the web page has been transferred, the network releases the resources on the air interface again after some time of inactivity. The channel is not released immediately to ensure a fast reaction to new data packets. This also wastes some capacity on the air interface, but is necessary to reduce delays. Let’s assume that these effects reduce the efficiency of the air interface by 2/3. This reduces the number of simultaneous users per cell from 1000 to about 333.

Busy Hour: In most networks, there are certain hours of the day during which users are more active then during others. Let’s assume that during busy hour, usage is 5 times higher. This reduces the number of users per cell down to 66.

On the other side, a single base station site is usually comprised of 3 cells, each covering a 120 degrees sector. Thus, the number of high speed Internet users per base station increases to about 200.

All right, let’s talk about money. Let’s assume that a high speed Internet user would pay around 30 Euros a month for anytime, anywhere Internet access. 200 subscribers/cell * 30 Euros * 12 months = 72.000 Euros. Accumulated over the lifetime of a base station which I assume to be 10 years, that’s 720.000 Euros. I am sure the cost of the base station and operational costs are surely lower. In addition, the base station is also used for voice telephony and other low volume Internet applications such as MMS, which generate a lot of additional revenue for an operator.

The bottom line: There is really no reason for mobile network operators to complain and keep prices at the current level except for their margin. Furthermore, HSDPA is already on the horizon which increases efficiency of the base stations and subscriber speeds.