Edition 25/2008 of the C't, a renowned German computer magazine, contains a number of interesting articles around mobile Internet access. In one of them, 3G USB dongles have been tested and those capable of 7.2 MBit/s in downlink (HSDPA category 7/8) have reached a maximum speed of 5.76 MBit/s. Impressive, that's even higher than what I experienced myself. The test were performed on the Hanover exibition ground, where both T-Mobile and Vodafone have upgraded their 3G network and their base station backhaul to support these speeds. I assume the tests were done while no exhibition was in progress, i.e. no traffic in the cell and also no or only little traffic in other cells in the neighborhood, which means only little inter-cell interference. They also tested HSUPA and achieved uplink data rates of around 1.8 MBit/s. Again, very impressive for a live network setup.
Author: Martin
GAN for LTE: A shot accross the bow for 3GPP?
LTE is a great technology but it has one Achilles heel: No built in telephony solution that will work when network are first rolled out. I've blogged before about the different alternatives for voice over LTE before, such as IMS, Voice Call Continuity, CS Fallback and a Study Item how to connect a circuit switched MSC to the LTE radio access network. While the last one is only a study item and not standardized yet, the first three are standardized but either complicated or, in the case of CS fallback, not a long term solution.
Looks like some operators are not very happy with the state of affairs and have looked elsewhere for help. At the recent LTE World Summit in London, Motorola and China Mobile have both said that they are considering GAN over LTE as a further alternative. GAN is used today in some 2G/Wi-Fi phones for Voice over Wifi at home. What it basically does is it establishes an encrypted IP tunnel between the mobile and the GAN controller at the border of the operators core network, and then tunnels both signaling and speech data to the MSC. Furthermore, the mobile and GANC are able to perform handovers between the Wi-Fi connection and GSM for ongoing calls. In effect, GAN hides the access network (Wi-Fi in this case) from the operators circuit switched core network.
The solution proposed by Motorola at the conference, GAN would do the same for LTE. After all, an IP connection is an IP connection, the core functionality of the GANC does not care if the interface to the user is Wi-Fi or LTE.
On his blog, Zahid has a slide of the Motorola presentation that shows how the network setup could look like. The figure shows an interface between the Mobility Management Entitiy (MME) and the GANC which I think is probably for handover co-ordination. When the MME detects that a handover is necessary to UMTS or GSM, it informs the GANC which can then ensure that an ongoing voice call survives the handover.
The advantage of this approach over the evolved MSC approach, which only exists as a 3GPP study item so far, is that the current circuit switched network infrastructure does not have to be changed. Even though the changes required for the eMSC are minor in comparison to IMS and VCC, they still need to be standardized and implemented by the major infrastructure manufacturers. The GAN approach on the other hand requires some modifications in the mobile and the GANC only, which could well be made without waiting for 3GPP.
>From a design point of view I think the eMSC would be a much more elegant and native approach to the issue. But in practice, elegance does not always win if it is more complex, or as in this case, meets reluctance in the standards bodies.
So, let's see if this 'dear 3GPP, we either do it with you or without you' announcement will change the attitude of some players.
Thanks to Zahid Ghadialy for his coverage of the LTE World Summit
My Take-Aways from Nokia World 2008
Once a year, Nokia hosts a 2 day conference to demo to the world what's in store from Nokia for the next 12 months. This year, Nokia World takes/took place in Barcelona this Tuesday and Wednesday. I haven't been there in person, but Nokia and WomWorld have made sure that those not on site could also watch the keynote speeches and product introductions via the web. Well done, Nokia, not a single glitch, no capacity issues, the live-streams performed flawlessly at 800 kbit/s.
You've probably already heard or seen about the new Nokia N97 introduced there so I'll just link to the keynote video where Anssi Vanjoki introduced it and a link to YouTube with first impressions of the look and feel as well as how the OS looks like and behaves for a general overview. Very insightful and I guess that's going to be my next device, if I can wait until it is released. Forecast 2H09. A long wait…
Here are the bits an pieces of hardware and software enhancements that I think will make a difference:
- Form factor: I like the idea of a small QWERTY keyboard hiding under the screen as well as the 3.5" 16:9 touch sensitive display. Thinner than my current N95 and not as wide as the iPhone makes it perfect from a handling point for both one hand and two hand operation. It's still more of a bar than a PDA shape.
- I expect it will still work with my Bluetooth keyboard for real fast typing which now gives three input methods, i.e. touchscreen, mini keyboard, and full bluetooth keyboard. The right input method for every location.
- 5 megapixel camera and flash. O.k. nothing really new here, the N95 has got that, too for two years now but it's still miles ahead of the 'toy cameras', as Anssi calls them, in competing products.
- A-GPS and electronic compass. While A-GPS gives you the location it can't tell the phone in which direction the user is looking while he stands still. That's an issue for street navigation, especially when you've marked the place you want to go beforehand, leave the metro station for example, your location is shown on the map but you have no idea in which direction to walk at first. It happens to me often enough. The compass should help with that. I'd be interested how that compass works from a practical point of view. Does anyone know?
- Also, the compass will be great to get more information about things you see together with Nokia maps. Though I think not yet in the product, Nokia is thinking in the right direction here, to send the location and orientation to a sever in the network, which then return information about what you are seeing like Wikipedia entries, map overlays, etc. So far I always assumed that such services would require the user to take a picture of what he sees which is uploaded to a server and then analyzed. With A-GPS and compass, things are much simpler, no need to analyze a picture.
- Nokia Maps enhancements: Quite a lot of announcements of what will happen here over the next year. Route overview for navigation will be included, something I am really missing today, terrain mode looks very nice, and 3D representation of sights. Also, Nokia has promised to include user generated content in Nokia maps, something I've been waiting every since I first used GPS and Nokia maps. Also, they are planning to include the location of other users in Nokia Maps so you can see where your friends are, if they wish so. And finally, synchronization between Maps on Ovi and Maps on the phone for planing trips on the PC and then downloading locations etc. you have marked to the phone automatically.
- Active idle screen enhancements: Widgets on the idle screen, customizable by the user to see his latest e-mails, what's going on on facebook, weather forecast, RSS stream, contacts, meetings, etc.
Nothing announced today is a revolution, but, I think these things are a powerful evolution over the current already great N-series devices and will definitely keep the competition going in the smartphone sector. Now, Nokia, let's just get this device and the new software out there as soon as possible. I can hardly wait.
The Second Wave of Mobile Web Users is Coming
When you sit in a restaurant and see how non-geeks at the next table check their Facebook accounts on their smartphones before the food arrives; if your colleagues to whom you have preached for years about the benefits of mobile e-mail and mobile web browsing without much success suddenly ask you which phone they should buy for that; when your friends proudly show you how cool opera mini is without being asked; when at meetings half the people attending now have a 3G dongle attached to their notebook; then I think the mobile web and mobile Internet are really about that have a big breakthrough in the mass market. Well, all of these things have happened to me recently so we must be close. I call it the second wave because the first wave were the geeks, the minority, and they have used it for some time now. The second wave however, are the 'normal' people, the majority. Finally…
3GPP Work Item: Multi Standard Radio (MSR)
Just a few days ago, I've speculated about GSM 'virtually' surviving for quite some time in base stations which have radio and digital modules capable of handling several air interface technologies at the same time. Looks like Ericsson has also been thinking in this direction and has recently started a Work Item in 3GPP to explore Multi Standard Radios (MSR).
The main topic of this work item is to define physical layer characteristics when one transmitter sends out several carriers. So far, all characteristics like neighbor interference and blocking where defined around a single carrier. For Multi Standard Radios, the same definitions now have to be applied around all the carriers of one base station transmitter.
Good places to look for further info are GP-081607 which contains a nice figure on how a single radio module could handle GSM, UMTS and LTE together. GP-081608 is also quite interesting, again some figures and a list of frequency bands for which MSR should be explored first. As per this paper, Ericsson would like to explore Multi Standard Radios for UMTS and LTE for the 2.1 and 2.5 GHz band (band 1 and 7), and GSM, UMTS and LTE combined radios for the 850 MHz band (US, Canada) and 900 MHz (Europe, Asia) (band 5 and 8).
The Work Item description (RP-080758) lists Alcatel-Lucent, Huawei, Nokia Siemens Networks, NTT DoCoMo, TeliaSonera and T-Mobile as supporter, so E/// is far from alone.
Vodafone Germany Interested in Cable Company
Today, I noticed a report on Teltarif that Vodafone Germany is looking into buying Kable Deutschland, one of the big German cable Internet (and TV) providers. It is speculated that the price would be around 2.5 billion euros. Quite a bit of money and yet another impressive indication that mobile only networks are a thing of the past. Both Vodafone and Telefonica O2 are already offering DSL services in Germany today but I guess those activities would pale against buying a cable operator. In my opinion, having strong fixed and wireless assets is a must to offer an all in one communication solution to private customers for both home and while they are away. And I guess femtocells / home gateways with 3G and Wifi built-in together with local IP access from 3G mobile phones would be an important part of such a strategy.
Sorry for not linking to the original article, I posted this entry from my mobile phone.
Femtospots
These days I was wondering if in the mid-term, femtocells might replace public Wi-Fi hotspots!?
With the rise of 3G USB keys and notebooks with built in 3G connectivity, the popularity of Wi-Fi hotspots, especially paid ones, is likely to degrade over time. Once people have a 3G card anyway and have instantaneous connectivity anywhere, people just won't bother anymore to search for a public Wi-Fi hotspot and go through the manual login process. In addition, femtos remove another shortcoming of public Wi-Fi, the missing air interface encryption which today leaves the door wide open for all kinds of attacks.
With rising demand for Internet access in hotspot areas such as hotels, airports, train stations, etc., HSPA or LTE femtocells might be the ideal replacement for aging Wi-Fi access points which at some point have to be replaced by new equipment anyway. So mobile operators such as T-Mobile, Orange and others, who have a dual 3G / Wi-Fi strategy today could at some point just make such a move if they see that use of their Wi-Fi systems is decreasing and use of their 3G/4G macro base stations in the neighborhoods of their Wi-Fi installations is significantly increasing.
Some 'dual-mode' operators might even have a database with the geographical location of their base stations and their Wi-Fi installations. Together with traffic statistics of both systems an automated system could document changes over time and could be used to help predict when and if a replacement of the Wi-Fi access points for femto cells might make financial sense. After all, femto cells are just as easily connected to a DSL line than a Wi-Fi installation.
Maybe some femto manufacturers even come up with integrated Wi-Fi/Femto boxes for public installations with the Wi-Fi being used to create a wireless mesh between several nodes in locations with only a single backhaul line and for access for those people not yet having 3G connectivity. Agreed, femto vendors today mainly position themselves around the femto base station for home networks but public femtos might be an interesting opportunity as well.
Space Invaders and 2D Barcodes
Do you know Space Invaders and the artist that puts them on walls in many different cities? If not you might want to have a look here. So what does this have to do with mobile and wireless? Looks like somebody has now started to add another dimension to this with 2D barcodes. If you have a mobile phone with a 2D barcode scanner, take a look at this picture, click on "full screen resolution'" to increase the size of the 2D barcode and point your mobile towards the screen for the application to decode the barcode. Very interesting result… 🙂
Found via the Paris picture stream in Jaiku. Social networking at its best!
What happened to Low-Power and High Speed Bluetooth?
It has been very quiet at the Bluetooth front for over a year now. The last time I heard of Bluetooth in the press was when version 2.1 of the standard was released in summer 2007 which promises simpler pairing procedures and updated security protocols and procedures. I haven't seen much of this in practice yet, however. Also, there have been announcements on an ultra low power implementation for very small devices such as sensors and watches by including Nokia's Wibree developments and very fast transmission rates by porting the upper layers of the Bluetooth stack over to Wi-Fi. Both announcements were also made back in the middle of 2007. Since then, no word. Anyone's got an update?
WPA Insecurities
Before Wired Equivalent Pricacy (WEP) encryption mechanism of Wi-Fi was fully broken, the industry acted quickly and pushed out a new Wi-Fi encryption scheme to the market called Wi-Fi Protected Access (WPA) Temporal Key Integrity Protocol (TKIP). WPA had a number of security improvements over WEP and so far was considered to be fully secure. Looks like this is no longer quite the case as Martin Beck and Eric Tews have recently published a paper on how they have partly cracked WPA encryption.
Partly in this case means that under a number of circumstances, all not unrealistic, it is possible to recover the encryption key for the data stream the key STREAM for ONE very short and specific type of packet from the access point to a client device within about 12 minutes plus the key used for generating the message integrity code (MIC). The attack can't recover the key for the reverse direction so the attack can not be used so far to gain full access to the network. The attack is limited to ARP (address resolution protocol) management packets for which most of the content is known in advance.
In practice this means that the attacker can then send up to 7 freely constructed packets (each in one QoS chain) to a client device. It is NOT possible, however, to decrypt other packets with the knowledge gained. Things that could be done with this, however, is to trigger intrusion detection systems or to trick a client into some sort of action and reporting the result to the destination IP address given in the packet, which could be in the Internet. For details see their paper here.
Two remedies are suggested in the paper: One of the requirements for a successful attack is that the timer responsible to force a re-negotiation of the ciphering key is set to a value higher than 12 minutes, which is usually the case. Many access points, however, allow to set the timer to a lower value. Beck and Tews therefore suggest a timer value of 2 to 3 minutes.
Another way to prevent the attack is to use WPA2, which uses CCMP/AES (Advanced Encryption Standard). Most access points and devices sold in the past 12-24 months are capable of this 802.11i compliant authentication and encryption scheme. In my case, I had to update my Windows XP Service Pack 2 with this Microsoft Patch before I could activate WPA2.
Fortunately, most access points allow WPA/TKIP/RC4 and WPA2/CCMP/AES to run simultaneously. Thus, WPA and WPA2 capable devices can be used in the same network and a WPA device, while itself being vulnerable, does not compromise the security of WPA2 devices.
Since only the data flow from an access point to a device can be broken this way, Since only single ARP packets can be decrypted and only short packets can be injected the usefulnes of the attack is quite limited for the moment, unless, of course, somebody figures out how to open up the reverse direction. another loophole like triggering an IDS system or to exploit an OS vulnerability with the few short packets that can be sent without knowing the key.