WirelessMoves

Some people would probably still say today that they don't need or want Internet access when going on vacation on a cruise ship or to a remote island. But I suppose their number is on a steep decline and cruise ship operators are investing in Wi-Fi Internet access on their ships not only in special areas but in cabins as well. According to this article (in German) the pleasure costs between 25 euros per week for "social media" access to 99 euros for 3 GB of data for a week on a ship of one of the major cruise lines.

The article doesn't mention what kind of backhaul is used but it's likely to be satellite. There's different kinds of technologies and (one of?) the latest and greatest seems to be from O3b, a company about which I wrote a post in 2008. It looks like in the meantime their medium earth orbit satellites (at an altitude of 8.062 km) are up and running and their public list of customers includes a cruise ship operator (though not the one mentioned in the first post linked to above) and remote islands. The specs advertised on their web page is a top speed of a single transponder of 1.6 Gbit/s and round trip times of around 150 ms. Each satellite has many independent transponders that can direct their beam to a specific area which hints at the capacity and user experience that can be achieved even if several hundred people on a ship need access simultaneously. Here's a video that demonstrates how the system works with two antennas that track the satellites.

And a final thought: I wonder if the uplink/downlink ratio on a cruise ship with lots of people posting their pictures and videos to social media websites is significantly different from the "land" average!? So apart from pleasing customers, a cruise line you probably can't get any better advertising than people posting their pictures in real time to Facebook…

Some heart warming nostalgia today: For some time now, the GSM logo initially designed at the end of the 1980s and used on a lot of GSM related products in the decades afterwards is rarely to be seen these days anymore. But there are some who still use it on new products. Have a look at the new 2015 Telecom Italia SIM card I've recently been given. It's not big and prominent anymore but still there. I wonder what the intention was to put it there. Perhaps by someone with nostalgia in his or her heart? We'll probably never find out but it made me smile nevertheless. And just in case you wonder what the meaning is behind the for dots in the logo, have a look here.

For about half a year I ran a somewhat outdated version of Selfoss on my server at home for RSS feed reading for a simple reason: At the time a change was proposed to integrate marking all displayed entries as "read" into the scrolling mechanism. I much preferred this over the solution that made it into the following release with which you had to disable scrolling to get a new button to mark entries as read. As other changes were minor I decided to remain on the old version and keep the suggested patch running on my system. Github makes it possible.

Over the weekend, however, I updated to the latest version once more despite the feature not being integrated because of two very interesting new features: There's a new feature to read full posts for those RSS feeds that only show the first part of the original entry. For a previous version I came up with dedicated code for a specific web site. Now, however, someone seems to have cracked the nut of how parsing a full web page and stripping out the text and pictures in a more generalized way. I gave it a try with one of my feeds and it worked perfectly. Enough a reason to switch and great to have a choice 🙂

Once per year I review which software I've used most and to which projects I'd like to donate some money to in return. After all, free software is not "free as in beer" but "free as in freedom". This time around I donated to six projects which had the most impact on my daily use of computers and smartphones.

As I use Ubuntu on countless devices including several servers my first donation went to them this year. Also, I think their push for a single OS and user interface for all devices from smartphone to TV is an important project that should be funded and supported.

Firefox and Thunderbird are my web browser, email client and calendar of choice and Mozilla is far too much dependent on donations from the advertising industry. My donation will change little in that regard but every penny counts.

Without Libreoffice, Linux on the desktop is hardly imaginable and so I decided to donate something to the TDF (The Document Foundation) as well. Great job done guys, thanks very much!

A website I visit several times a day is Wikipedia so I decided to donate to the Wikimedia foundation as well.

Again, my world without that project would be quite different. Another big thanks goes to Openstreetmap. In addition to regularly updating and contributing to the database I felt it would be a good thing to donate some money for to keep their infrastructure running.

And finally I made small donation to the KeypassX project as I rely on their software to keep my passwords save day in and day out.

Thanks to all people working on these projects, paid or volunteering, the computing world would be not as great as it is today without you!

Telegeography reports that Telenor Norway's CTO Magnus Zetterberg has recently said during the company's analyst and investor day that they intend to switch-off their UMTS network in 2020 and their GSM network in 2025. While others such as AT&T have already stated their GSM exit in 2017, the rest of the world will likely follow Telenor's example as there is too much embedded infrastructure around that still uses GSM.

Anyway, this is the first announcement of a network operator I have seen concerning the switch-off of a 3G UMTS network in the not too distant future. If you know of any others please leave a comment, I'd be interested. From my point of view that makes a lot of sense. In Germany, and I suppose in many other countries as well, there are few phones sold these days in network operator stores that are not LTE capable. That means that in 5 years from a large majority of smartphones and other end user devices used in the network will be LTE capable.

In 2011 I wrote a post on what I saw as the preconditions for switching off UMTS in the future. Apart from a critical LTE device mass my other two points I raised at the time, LTE coverage and Voice on LTE, seem quite achievable in 5 years time. Already today, LTE coverage is quite impressive in Germany and elsewhere, and is, due to the use of the 800 MHz band, already better than 3G coverage. And as far as voice over LTE is concerned that is likely to happen in the next 5 years as well. Quite a number of network operators have launched VoLTE in recent months and in 5 years time either nobody will talk about VoLTE anymore or most network operators will have launched it. In either case that's not going to be a showstopper for shutting down 3G networks anymore, either.

Couple the 3G switch-off with a base station equipment refresh that happens every few years anyway and the freed-up spectrum can immediately be used for LTE. So while in 2011 a UMTS switch-off was still rather theoretical, a switch-off in 2020 looks quite practical and realistic from a 2015 perspective.

Compared to other countries in Europe, prices for mobile data services in Germany are still pretty high. A gigabyte of mobile data can be had for around 10 euros if you look around a bit (but still quite a difference for the unlimited amount of data you get for 18 Euros in Austria, for example). Anyway, how long does it take to use up this gigabyte?

In Germany, LTE is available at speeds up to 300 Mbit/s now when allowed by the contract and when being close to the center of a cell that has carrier aggregation with 2×20 MHz activated. If all those conditions are met, 1 GB of data can be downloaded in  in less than 30 seconds. But let's make a more realistic example, let's say I get 50 Mbit/s out of the link, which is not so unusual in many places. At that speed it takes around 3 minutes to use up my data bucket for the whole month if I really wanted to.

Now let's do an interesting thought experiment with that number: How many users could do that in one month with one base station site? A month with 30 days has 43.200 minutes. Divided by 3 gives you 14.400 users who could run that exercise sequentially. On the other hand, most cells have 3 sectors, each with an independent data stream so if those users are neatly distributed around the base station site that number goes up again. And now multiply that number by the average 1 GB data bucket price.

Of course networks are not fully loaded and due to interference from neighboring cells and distance from the base station not all users get 50 Mbit/s out of an unloaded cell. But even if the number is an order of a magnitude lower it is still impressive.

A couple of days ago a reader left a comment to a previous post on LTE 900 MHz in the Netherlands that an LTE network now also went live in the 450 MHz range in Finland. Thanks for that! I was intrigued so I had a closer look. The network seems to address mostly businesses and moving vehicles at first and private summer house owners in Finland a bit later.

What's The Deal For Today's Users?

I tried to find out which band is used for that network but couldn't find a definite source. So I assume it's FDD band 31. If that is indeed the case then it's at 5 MHz carrier at most (for which I don't have a confirmation either so it's a guess, too), compared to 10 MHz used in the 800 MHz band and 15 to 20 MHz carriers used in band 3. In other words capacity and top speeds are quite limited. So from that point of view nothing to write home about. On the other hand a 5 MHz LTE carrier in a summer house far off the beaten path is better than nothing at all, at least today. With rising bandwidth demands, however, a 5 MHz carrier won't cut it for long even in far away places…

The historical perspective

Oh yes, why only 5 MHz? It looks like this is a spot left over from old analog networks (e.g. the C-Netz in Germany, which used 451,30–455,74 MHz and 461,30–465,74 MHz according to Wikipedia. This range is not fully overlapping with LTE FDD band 31 but that's not very surprising because in the 1980's, there was no common European, let alone, worldwide standard. But from a historical perspective the 5 MHz bandwidth is interestig because I always imagined that more bandwidth was used for these networks. And then GSM comes along for which 25 MHz of bandwidth was reserved for each direction, i.e. 5 times as much as for the networks that were in use at that time. Quite a bold move for the time I would say.

Half a decade ago, network operators in Europe have started to use UMTS not only in the 2100 MHz band but also in the 900 MHz band that was, up until then, only used for GSM services. A good example is France with rural coverage and big cities in the UK. Now it seem seems LTE is also getting some traction in what is called LTE band 8. According to a report by Telegeography, T-Mobile Netherlands has started using LTE in the 900 MHz band in Amsterdam. An interesting move, just makes me wonder how much spectrum they have available. On the device side LTE band 8 is already supported by a number of devices, for example by the current generation of Apple devices. In other words there will be immediate use of the extra resources.

When I recently had problems keeping a UDP session alive over a NAT router I found out that my Raspberry Pi acting as the NAT router only keeps port mapping for the UDP session for 3 minutes. If there is no traffic during that time the mapping is discarded and all incoming packets afterward will no longer be delivered. While that's probably o.k. for most applications it didn't work for me. Fortunately it can be easily changed.

The following commands shows the current UDP session timers variables and their values:

sudo ls -l /proc/sys/net/ipv4/netfilter/ip_conntrack_udp_*

sudo cat /proc/sys/net/ipv4/netfilter/ip_conntrack_udp_*

On my Rasperry Pi I get 30 seconds for the initial timeout and and 180 seconds once the stream is established. The following command changes the timeout for new streams to 20 minutes:

sudo sysctl -w net.ipv4.netfilter.ip_conntrack_udp_timeout_stream=1200

And to find out which TCP and UDP streams are currently in the NAT translation table the following command can be used:

sudo cat  /proc/net/ip_conntrack

The second value in each line is the number of seconds remaining before the entry is removed if no further packets arrive that are part of the stream.

And for more details have a look here.