3G Connection Sharing – Part 3: The D100

D100
While the software on the Fritzbox for 3G connection sharing over Wi-Fi is still an early beta, I have recently also tested the Huawei D100, a box dedicated for 3G connection sharing. So far, I've seen it advertised by 3 in the UK (with contract only) or by 3 in Austria, here unlocked for 99 euros. Needless to say I preferred the Austrian variant and went into a shop while in Austria recently to buy one. I have now used it for several days with a E220 3G USB stick in the Mobilkom A1network and I have to say I am very impressed by stability of both the Wi-Fi and the 3G connection and the ease of use of the box.

Once power is switched on and the power on button has been pressed, the box automatically attaches to the 3G network and establishes an Internet connection. What I've found a bit odd is that the power button has to be pressed for the box to start. This is a bit inconvenient after a power outage for example. Should the 3G connection drop while being online, the box is smart enough to figure out something is wrong and automatically re-establishes the connection within a couple of seconds. It happened two or three times in the course of a couple of days but it's hard to say if that was due to the D100, the 3G stick or the network.

The Austrian D100 comes preconfigured for all Austrian networks, but it's also possible to add configurations for SIM cards of other operators and countries. The page for this is a bit hidden but one found, it's pretty much straight forward.

While most people will probably use it for Internet connection sharing, Dean Bubley recently had a number of other interesting ideas of how to use what he calls 'the dongle dock'. Have a look here, especially the last paragraph. Now I need to get a femto to test his idea 🙂

HSPA State Change Measurements

A1-state-changes Last week I did some measurements to get an idea of the time required when switching between different HSPA air interface states. While data is transferred, the mobile is usually in Cell-DCH state on a High Speed Shared Channel. When only little or no data is transferred, the connection transferred to the Forward Access Channel, which is slow but has little overhead for both the network and the mobile device in terms of control measurements and power adjustments commands. If no data is transmitted for a longer duration (e.g. 30 seconds) the connection is put into Idle state. While the IP address is retained, the physical connection between the mobile and the network is severed.

As can be seen in the picture on the left, the round trip time to the first hop in the network of a ping packet is around 100 to 120 milliseconds while the mobile is using a high speed shared channel. While on the slower forward access channel, round trip time increases to 240 to 260 milliseconds. Moving from the high speed shared channel to the forward access channel is relatively quick, it takes around 550 to 600 ms (minus the actual round trip time of the packet itself). Going back to the high speed shared channel takes a little bit more time, around 1000 to 1500 milliseconds.

When using a 3G dongle with a notebook, a connection is rarely set into idle state as there is always one program or another such as an instant messenger, VoIP client, etc., that feels it needs to send a keep alive message to a server in the network before the idle time can expire. Therefore I haven't measured it this time. In the past, I've seen values around 2500 to 2800 milliseconds.

Some say that the effect of this state switching is that web browsing feels a bit more sluggish over HSPA than over a DSL line, which always offers Internet connectivity at full speed without the need of state switching. I use 3G connectivity a lot and quite frankly, while I can feel a difference, it's absolutely no problem to work and live with it.

And here's a quick overview of the test setup: Mobilkom Austria 3.5G HSPA network, a notebook connected via Wi-Fi to a D100 Wi-Fi/3G gateway, connected to a Huawei E220 3G USB stick, HSDPA category 6, no HSUPA.

Europe-wide Prepaid Data Roaming

Here's news on an interesting offer recently started by German MVNOs using the e-Plus network (Simyo, Blau, Alditalk): Since October 1st, their prepaid SIM cards are now activated for data roaming in the EU and a number of other countries. Price per 100kb block is 0.19 euros. While not exactly cheap, it's a 10th of their previous price and a 10th of the price of most other operators around Europe.

I wouldn't use it with a notebook but for small screen web browsing and mobile e-mail reception it sound quite affordable. In the countries they support data roaming outside the EU (btw. Switzerland is part of that list…) the price per 100 kb block is 49 cents. For details, see the Prepaid Wireless Internet Access Wiki.

Recently, I tried the offer with my Alditalk prepaid SIM while in France. The first time I tried, right after the start of their offer, 49 cents per 100 kb block were charged. I sent an eMail to their hotline, asking what was going on and they admited that they have a problem with their billing system and returned the money that they overchaged. When I tried again last week, the billing system was fixed and the proper amount was charged.

Uplink Downlink Ratios Revisited

Ul-dl-ratio
I've been traveling for two weeks now in Austria and Italy and have been online throughout that time 'only' via 3G to do my daily business thanks to prepaid 3G Internet access. Wherever I went, 3G HSPA access has been available so using the Internet with a 2 MBit/s downlink on average didn't feel much different from using DSL at home. I've reset the data counters on my N95, which I used as my 3G modem during the trip, to get an idea on how much data I exchanged. In the past seven days, I used about 750 MB in total for e-mail, web browsing, company Intranet access, VoIP, IM, etc.

As can be seen on the picture on the left, my uplink to downlink ratio is around 1:2 and not 1:10 as I observed during a previous trip. That's probably got something to do with the fact that this time, I received and sent many e-mails with massive file attachments (those 5 MB PDF or PPT files everybody likes…) and have been using VoIP extensively for lengthy conference calls. With VoIP, the uplink / downlink ratio is 1:1 and generates around 20 MB per hour in each direction.

From a network point of view a 1:2 ratio means that I used about as much resources in the uplink as I did in downlink, since uplink transmissions are less efficient than those in downlink due to the smaller antenna and little transmission power compared to a base station. While in most situations, I could get uplink speeds of around 400 kbit/s, which is almost as fast as the uplink of my DSL line at home, I nevertheless wished I would have had a High-Speed Uplink Packet Access (HSUPA) capable device and network. Those 5 MB Power Point presentations do take quite a while to get transmitted.

Yes, one can never have enough bandwidth 🙂

3G Connection Sharing – Part 2: My Fritzbox DSL/Wi-Fi box speaks 3G now!

Fritzbox 3G
Recently, AVM, manufacturer of the 'famous' Fritzbox ADSL2+/Draft-N Wifi router, released a beta software that adds Internet connectivity via 3G USB keys to their router software. I really like this box as it's crammed full of features such as a DECT base station, SIP capabilities, meaningful status reports, Wi-Fi interference monitor, DSL line visualization, etc., and now also 3G capabilities with an external 3G modem.

While it wouldn't work with a Huawei E160 3G USB stick, I managed to get it working with a somewhat older E220. The software is still quite an early beta and the GSM/UMTS configuration page in the router is not updated correctly once the connection is established as it remains in the "trying state". Nevertheless the connection is established and the main configuration screen properly shows the IP address and connectivity state. The throughput is the same as if the stick was connected directly to the PC.

Kind of an inverse 3G femto cell and great for traveling when more than one person or device needs Internet access or in areas without DSL coverage. For traveling, however, a somewhat smaller configuration, e.g. a 3G stick in combination with a D100 is probably preferable. For most users, such a setup is probably a lot more practical than the 3G Internet connection sharing via a PC, as I described a long time ago in this post.

Polish 3G operator Play targeting Roamers for Mobile Broadband

Play-poland
It's fascinating to see how new ideas are emerging in different countries to market prepaid SIMs for Mobile Broadband Internet access. The latest and greatest I've seen to date comes from Polish operator Plus. Not only do they offer prepaid mobile Internet access, they even have English instructions on the sales package to make it easy for inbound roamers to use their service. I haven't seen that anywhere else yet. Details can be found here. Thanks to Chris_M for putting the information into the Wiki!

The Book Cover is Ready

Book-for-blog
Good news from the book writing project! After I delivered the manuscript to the publisher back in September, it has now been typeset, i.e. put in form and shape as it will appear in the finished book. Also, the front and back cover are ready now and the picture on the left shows how the front cover will look like. I have to say that I am very happy with it, in my opinion the colors and the images have been very well selected and integrated.

Only little work remains to be done now and then it will finally go to the print shop.

Here's the text from the back cover:

"Beyond 3G: Bringing Networks, Terminals and the Web Together"

Giving a sound technical introduction to 3GPP LTE and SAE, this book explains the decisions taken during standardization while also examining the likely competition for LTE such as HSPA+ and WiMAX. As well as looking at next generation network technologies, Beyond 3G – Bringing Networks, Terminals and the Web Together describes the latest mobile device developments, voice and multimedia services and the mobile web 2.0. It considers not only how the systems, devices and software work but also the reasons behind why they are designed in this particular way. How these elements strongly influence each other is discussed as well as how network capabilities, available bandwidth, mobile device capabilities and new application concepts will shape the way we communicate in the future.

  • Examines current and next-generation network technologies such as UMTS, HSPA+, WiMAX, LTE and Wifi
  • Analyses and explains performance and capacity in practice as well as future capacity requirements and how they can be fulfilled.
  • Introduces the reader to the current cellular telephony architecture and to voice over IP architectures such as SIP, IMS and TISPAN
  • Looks at mobile device hardware and mobile operating system evolution
  • Encompasses all major global wireless standards for application development and the latest state of the mobile web 2.0

If you would like to be informed when the book becomes available and haven't already done so, please send your e-mail address to gsmumts at gmx.de and I'll be happy to keep you up to date.

You can now also pre-order it at Amazon if you live in the U.S., UK, or Germany.


Asynchronous Communication – Why I like Instant Messaging

Despite having been quite a skeptic a couple of years ago when it came to Instant Messaging (IM), I have realized these days that I have fully integrated IM into my working and private life and today I wouldn't want back. In fact, if somebody calls me on Skype these days without sending an IM first to ask if I am available or to let me know what it is about, it feels a bit strange, almost like an intrusion.

Communicating with IM people

I usually don't call people on the phone that regularly use IM. In most cases the questions I have can be answered in a few words. No need to call and 'hard interrupt' the other person or myself. To me, IM seems more like a 'soft interrupt' with the option to ignore for a little while to finish something else first. I can even continue my work and once I have the answer I can quickly go back and fill in the gaps, if the task at hand permits.

While the amount of incoming and outgoing messages remain reasonable, I can get answers and answer questions myself pretty much on the fly without fully interrupting the main task I am doing at the moment. Much more efficient than making a phone call for both parties involved.

I can also see right away when somebody is busy or not available. So instead of calling and leaving a voice mail, I can set a 'notification event' in my messenger so I don't have to guess when the other person might come back or waste time in trying to call.

Communicating with Non-IM people

Seeing people being present gives me a sense of connectedness and the reassurance that I can quickly get help or advice when necessary. With people that are not connected, however, my business practice is quite different. Here, the only way to contact them is by phone or e-mail. While e-mail is definitely less intrusive than IM, you never know when the other person reads it or when he will answer it. And making a phone call will definitely interrupt whatever the other person is doing or I might not be able to reach him at all. It feels a bit like walking in the dark or playing the lottery.

No mobile-IM yet

What I haven't come around to using yet is IM on my mobile phone. Not that it's a technical issue, there are enough mobile IM clients available. Maybe that's because I also don't read my business e-mails on a mobile device since my questions and answers I get/send by e-mails are usually longer than what small keyboards, screens and not being able to look up things in documents, support. Or maybe I just don't want to be bothered while in transition!?

Interesting though how many of my friends, co-workers and customers are using mobile-IM these days, even those that generally questioned the usefulness of Internet access from mobile devices a couple of years ago.

So my question to you is: How do you feel about / use IM today?

P.S.: Have you noticed that almost everyone now uses an avatar (picture) in their IM program. I wonder how that happened!?

Bye Bye ATM

While ATM is used as a transport technology in backhaul and core networks for UMTS and ADSL today it looks like the technology is pretty much on the way out in next generation networks. In LTE for example, ATM no longer plays a role, everything is specified only down to the IP layer. The technology used below is up to the network operator. In many cases this will be Ethernet over copper (e.g. VDSL), fiber or Ethernet microwave.

Another example is the VDSL deployment of Deutsche Telekom (DT) in Germany. According to heise magazine 22/08, DT uses Ethernet over a Gigabit fibre (802.3ah) to their outdoor VDSL DSLAMs. Ethernet is also used over the last few meters of copper cable to the customer instead of ATM. While the VDSL modems can still do ATM, DT has decided to use Ethernet in combination with VLAN (Virtual LAN) encapsulation (802.1q). At the moment, only VLAN-ID 7 is used for all kinds of data, but there are rumors that DT plans to use several VLAN-IDs to separate IPTV from normal Internet access in the future with their IADs (Integrated Access Devices) that support Internet access, IPTV and (SIP) telephony.

IMS Service Discovery and Sharing

Recently, while in the dentist’s waiting room I had a bit of time to read another article from the always very interesting Ericsson Review Magazine. In the 2/2008 issue there are lots of articles on IMS. In the article on delivering the optimal end-user experience, the authors describe that their IMS application environment allows to share with other users which IMS applications one is using. This way, one can not only see if it is possible to use a specific application to communicate with someone but it’s also possible to see which applications others are using and thus to discover new services. Kind of a viral marketing approach.

I haven’t read about this in any IMS articles so far and it strikes me as a good idea, not only for the IMS domain. From the article, it’s not quite clear if this is something proprietary of the Ericsson IMS client environment or something that was standardized in 3GPP or OMA. If this is part of an IMS standard and you know where to find it, please leave a note in the comment section.