GPRS Roaming eXchange (GRX) for LTE/EPS Networks

The GSM Association (GSMA) has came to the realization that GPRS roaming based on bilateral relationships between individual GPRS operators is incredibly complex and expensive to maintain, in particular if the number of roaming partners is high. In fact, each operator will have to have N(N - 1) dedicated links to other operators (given that N is the global numbers of operators for which roaming should be supported). The GSMA has therefore recommended the use of a GPRS Roaming eXchange (GRX) for the Inter-PLMN GPRS roaming scenario.

The GRX is built on a private or public IP backbone and transports GPRS roaming traffic via the GTP between the visited and the home PLMN (Figure above). A GRX service provider has a network consisting of a set of routers and the links connecting to the GPRS networks. Moreover, the GRX network will have links connecting to other GRX nodes to support GRX peering between networks.

The GRX service provider acts as a hub, therefore allowing a GPRS operator to interconnect with each roaming partner without the need for any dedicated connections. This allows faster implementation of new roaming relations, faster time to market for new operators, and better scalability since an operator can start with low-capacity connections to the GRX and upgrade them depending on the bandwidth and quality requirements of the traffic. Other benefits of GRX are as follows:

Support of QoS: This aspect that will be very important for the GPRS services and, in particular, for the transition to 3G systems.

Security: The interconnection between the home operator and the visited operator uses the private GRX networks, hence does not require the overhead of maintaining expensive IPSEC tunnels over the public Internet.

DNS support: Through GRX it is possible to support a worldwide ".gprs" DNS root, where the various GRX operators will collaborate in managing the root and each operator's DNS servers will be connected to such roots to provide translation of DNS names specific to one operator.

In conclusion, GRX is introduced for GPRS roaming to facilitate the network operators for the interconnection between networks to support roaming and will play a very important role for the transition to third-generation systems.

In the LTE World Summit, Alex Sinclair, Chief Technology Officer, GSMA mentioned about the important role GRX will play in the LTE networks. The figure below are his views on GRX.

Diagram and Initial text Reference: IP in Wireless Networks By Basavaraj Patil, et al.

More information on GRX is available in GSM Association IR.34 document.

LTE uniting the cellular world technologies

Nice picture from a presentation by Alex Sinclair, Chief Technology Officer, GSMA in LTE World Summit

The fastest and most powerful iPhone is here

Though Steve Jobs was not there, the new iPhone 3G (S) went on display at the Apple's World Wide Developers Conference in San Francisco on June 8. The 'S' stands for speed.

The new improved iPhone 3G (S) helps you download Web pages in a fraction of the time, and you can view email attachments faster.

Improved performance and updated 3D graphics deliver an incredible gaming experience, too.
The new phone can also capture video and boasts an improved capability for taking still pictures.
The iPhone 3G S will hit the market on June 19.

After a string of successes with the iPod and iPhone, Apple is hoping it can keep wowing shoppers with this latest version of its popular mobile handset. The iPhone 3GS will sport a number of upgrades from its predecessors – including a doubled capacity of 32GB; a digital compass; and the ability to record videos.

The larger memory will allow iPhone owners to store up to 7,000 songs or 40 hours of video on their handsets, which they can now download directly from the iTunes store.
Below is the summary of some of the features of this latest iPhone.

Video and 3-Megapixel camera:

You can shoot video, edit it, and share it - all on your iPhone 3G S. Shoot high-quality VGA video in portrait or landscape. Trim your footage by adjusting start and end points. Then share your video in an email.

The new 3-megapixel camera takes great still photos, too, thanks to built-in auto focus and a handy new feature that lets you tap the display to focus on anything (or anyone) you want.

Voice Control:

Voice Control recognises the names in your 'contacts' and knows the music on your iPod. So if you want to place a call or play a song, all you have to do is ask.

Compass:

With a built-in digital compass, iPhone 3G S can point the way. Use the new Compass app, or watch as it automatically reorients maps to match the direction you're facing.

Landscape keyboard, Cut, copy and past:

Cut, copy, and paste words and photos, even between applications. Copy and paste images and content from the Web, too.

Want more room to type on the intelligent software keyboard? Rotate iPhone to landscape to use a larger keyboard in mail, messages and notes.

Messages:

Send messages with text, video, photos, audio, locations, and contact information. You can even forward one or more messages to others.

Search:
Find what you're looking for across your iPhone, all from one convenient place. Spotlight searches all your contacts, email, calendars, and notes, as well as everything in your iPod.

Accessibility:
iPhone 3G S offers accessibility features to assist users who are visually or hearing impaired.
These features include the VoiceOver screen reader, a Zoom feature, White on Black display options, Mono Audio, and more.

Internet tethering:
Surf the web from practically anywhere. Now you can share the 3G connection on your iPhone with your Mac notebook or PC laptop.

Voice memos:Capture and share a thought, a memo, a meeting, or any audio recording on the go with the new voice memos application

Nike + iPod:

iPhone includes built-in Nike + iPod support. Just slip the Nike + iPod Sensor (available separately) into your Nike+ shoe and start your workout.

Stocks:

Stocks on iPhone shows you charts, financial details, and headline news for any stock you choose. Rotate iPhone to see even more detailed information.

YouTube:

Watch YouTube videos wherever you are. Log in to your YouTube account to save and sync bookmarks and rate your favourites.

VoLGA: Bringing Voice to LTE

Voice is becoming an Important issue for seamless introduction of LTE services. Even though most people think that LTE will start with the Broadband Dongles, it is important to resolve the issue sooner rather than later.



VoLGA Forum is one such body proposing a solution and its backed by quite a few well known industry players.



In the LTE World Summit, Franz Seiser of T-Mobile Germany spoke about VoLGA. Here is a summary from his presentation:

In order to ensure LTE will be used as much as possible, voice-and messaging services need to be supported on LTE networks in high quality asearly as possible.

The main Drivers being:

• Ensure acceptance of LTE as an possible next generation PLMN
• Shift traffic to new network as fast as possible
• Avoid price competition with DSL
  

The industry needs a stable, scalable voice and SMS solution forLTE:

• delivering a seamless user experience (voice hand-over to existing 2G/3G networks)
• with proven, commercial quality
• availability in 2010 (SMS) /2011 (voice) latest

In a post earlier, I discussed about the possible voice options for LTE and that generated quite a discussion relating to GAN. Recently Dean Bubley and Martin Sauter have covered this VoLGA issue and in general Voice over LTE in far more detail than I have earlier or even in this post. Please see the links at the bottom to read their post details.

Specified 3GPP solutions for Voice/SMS in LTE do not meet all requirements because:

CS Fallback ruled out due to customer experience and non-LTE usage

• issues with customer experience (call set-up time increase >1.5sec., no parallel voice/data if legacy network is 2G w/o DTM)
• not using LTE radio for voice
• requires changes to Rel-4 architecture MSC-Servers
• has much more impacts than originally envisaged

IMS based solution has very high complexity; availability and stability notfeasible in time, roaming eco-system is not yet existent

• solution would consist of IMS platform, various application servers and a major upgrade/change to Rel-4 architecture MSC-Servers
• no eco-system in place yet for IMS voice/SMS roaming and interconnect (only GPRS data or CS eco-systems are available today)
• solution requires updates/changes to quite many IT systems and processes as well

Key Objectives for Voice/SMS over LTE Solution is to Re-use as much as possible of existing systems, mechanism and eco-system while avoiding proprietary extensions to 3GPP nodes

• build upon existing Rel-4 CS network and investments
• “do not touch the MSC”
• build upon fully 3GPP compliant Rel-8 EPC/LTE network
• re-use existing CS roaming/inter-connect regime
• minimise impact on UE, especially on user-interface

As a result, the simplest solution is “Voice over LTE Generic Access” or VoLGA

What is VoLGA?

• A technological approach for delivering voice and SMS services over LTE access networks
• Leverages a mobile operator’s existing core voice network
• Derived from the existing 3GPP GAN standard

What is the VoLGA Forum?

A group of companies working to…

• Leverage collective technical skills to define VoLGA specifications
• Publish proposed specifications via the VoLGA Forum web site (coming soon)
• Facilitate the easy adoption of VoLGA technology by other vendors and operators

The group is open to interested parties in the mobile community

• See http://www.volga-forum.com/ for more information about joining

The main Highlights of VoLGA are:

• Full service transparency

Supports all circuit services over LTE

Supports IMS RCS and combinational services (CS+IMS) over LTE

Supports handover of active calls between LTE and GSM/UMTS

Supports expected LTE femtocell deployments

• Low risk, low investment

• Based on well proven 3GPP GAN standard

  Requires no change to existing MSCs and operational systems

  Conserves existing, extensive voice interconnection regime

To keep things simple, VoLGA is the best option available at the moment.

Further Reading:

• VoLGA Forum
• VoLGA Specifications
• Voice - Bearer Aware, Bearer Adaptive or Bearer Agnostic?
• The Volga-Forum: Taking the Quest For Voice over LTE out of 3GPP
• VoLGA - reinventing UMA for Voice-over-LTE
• LTE, mobile broadband & SMS - VoLGA vs. IMS

You can search multiple blogs (including mine) in a single search via the 3G4G search here. (Search at the bottom of the page).

NGMN put into our context

Here is a slide from Klaus-Jurgen Krath of T-Mobile Germany, which simplifies NGMN for us. NGMN or the Next Generation Mobile Networks intends to complement and support the work within standardisation bodies by providing a coherent view of what the operator community is going to require in the decade beyond 2010.

You can read more about NGMN here.

An old whitepaper titled "Next Generation Mobile Networks Beyond HSPA & EVDO" gives much more insight into NGMN vision, mission and details some of their recommendations. Its available to download here.

Cell Radius on Different LTE Frequencies

I mentioned earlier about the cell radius being 300 metres at 2.6GHz. Here is a diagram showing that.

The Case for Early LTE in the USA

Doug Wolff,Vice President , End-to-end LTE product management, Alcatel-Lucent spoke about "The Case for Early LTE in the USA" in the LTE World Summit. Here are the main highlights from his presentation:

Overview of US Wireless Market:

• With the penetration rate approaching 90% and the economy decreasing, customer and revenue growth are both slowing
• Data is becoming increasingly important to operators’revenue growth –driven by flat rate data plans and the iPhone
• Operators are developing new revenue models, including M2M and mobile advertising
• Consolidation continues --the top four operators have recently purchased: Alltel, Rural Cellular, Dobson and SunComWireless
• LTE deployments are scheduled to begin in 2009, using the already auctioned 700 MHz and AWS spectrum bands
• Increase in availability and demand for smartphonesand multi-featured devices
• Verizon & AT&T, with 60% of the market, focus on network quality and coverage –smaller operators jockey for position with pricing
• Operators have increased their focus on OPEX cost savings related to network spending

The US Wireless Users of Future will demand and consume more data. According to a survey done by Alcatel-Lucent, Consumers are more likely to be interested in video, image, location and Business in collaboration, video conference, data transfer. There is a very high likelihood of people signing up for 4G [sic] when it is available.

The US lags in broadband adoption. It ranked 21st in world in 2008 vs. 6th in 2001. Rural broadband lags urban/suburban areas. 21% of US (nearly 60M people) live in rural areas.

To encourage Broadband rollout especially in rural areas, Broadband Stimulus Bill has been proposed. The Bill highlights can be seen from the picture:


LTE can be an ideal candidate as it leverages wireline/wireless assets for rural access in the USA

• Digital dividend band (700/800 MHz) offers ideal radio environment for rural access
• Best available backhaul using microwave, GPON and optical aggregation
• Common aggregation and service routing offers converged access solution
  

Along with the technology, focus is also on services, etc. Verizon has recently Wireless LTE Innovation Center to foster the development of new devices and applications for its upcoming fourth generation, long-term evolution (LTE) network (see presentation). The main aim being:

• Accelerate innovative services
• Enable new business models
• Attract open innovation
• Enable multi-screen experience
  

Along with this there is n.g connect program that will help various players in the ecosystem to come together.

There is also a Verizon Open device/development initiative and they recently released its initial set of technical specifications for devices that will run on its Long Term Evolution (LTE) fourth generation (4G) wireless network. The specifications are available for download at www.verizonwireless-opendevelopment.com.

So in conclusion, the case for early LTE in the USA driven by End-user demand for enriched QoE and New market opportunities (M2M, rural zone, M-advertising, 700MHz spectrum..). This is being helped by Network & Ecosystem initiatives led by Verizon & Alcatel-Lucent for successful early LTE launch in the USA. Drivers & Enablers of early LTE in the USA are highly relevant in European & Asian Mature markets. An early rollout in USA will encourage early rollout in other markets.

Samsung unviels first 12 mega pixel camera phone

Samsung will release what it said is the world's first 12-megapixel camera phone this month, beating rival handset maker Sony Ericsson to market and jumping ahead in the megapixel race.
Samsung reinforced its leadership in the high megapixel cameraphone market by unveiling Samsung Pixon12 (M8910).Samsung will launch the Pixon12, which has a full-touch 3.1-inch AMOLED display, later this month in Europe and in other regions of the world in August.
Samsung is launching this camera phone with three keywords in mind i.e. Instant shoot, Instant see and Instant share which they think will provide incredible user experience.

Instant Shoot:
The Samsung Pixon12 enables users to take perfect pictures quickly and easily, thanks to a Dedicated Camera Power Key which gives users fast one-touch access to the camera function. Once the camera is turned on, users can aim and snap, capturing images as fast as today's advanced digital camera. Samsung Pixon12 also features fast image saving for next shot, so users can move to next shot within around 2 seconds. The phone provides the best photo quality by adopting innovative camera features. With Touch Auto-Focus (AF) tracking, users can simply select focus point with the touch of a finger, after which the AF function will automatically follow the object, keeping it in focus even as it moves across the screen. Moreover, Smart Auto feature allows users to capture the perfect images as the camera automatically changes the scene and mode based on its object, background and lighting. Images taken on the Pixon12 are worth showing off to friends and loved ones as they boast digital camera quality thanks to the phone camera's superb lens and Xenon flash. The 28mm wide angle lens also allows a better perspective and more full capture of a scene for consumers.

Instant See:
After they are done snapping, users can re-live and enjoy the pictures on the Pixon12's brilliant 3.1" AMOLED screen. The screen boasts a contrast ratio of 10,000:1 while providing power-saving features which increase battery life. Finally, the Pixon12 enables users to easily organize and manage photos with multiple ways of sorting - by tags, file names, ratings, and time. In addition, the multi-selection feature enables users to pull up images in groups rather than one by one, making viewing and editing photos much easier.


Instant Share:
With Samsung Share Pix, the Pixon12 lets users easily upload images and videos to popular social networking sites such as Facebook, Picasa, Flickr, MySpace, Photobucket, Friendster - a breeze. Add to that, the phone's high-connectivity functions including Wi-Fi and HSUPA capabilities mean that user's photos can be shared to their friends in no time. The Samsung Pixon12 will be available from end of June in European countries and it will be expanded to other regions in August.The announcement of the Pixon12 is a blow to Sony Ericsson, which has touted its Satio phone, previously named the Idou, as having a 12-megapixel camera. The Satio will be available in the fourth quarter.

Signaling latency in UMTS/HSPA and LTE

I think this is a very good self explanatory picture from a presentation by Qasara.

Do check out the 3G4G page for up to date presentations, whitepapers, etc. on LTE/SAE.

Nokia’s Ovi store launch didn’t go well

Nokia has desperately waited for the day when it can launch its Ovi store thus envisaging that it would provide a direct competition to the apples App store.

Rather what I have found out is that Nokia's worldwide launch of its much touted Ovi Store proved to be an utter disaster and didn’t go as planned.

For those of you whoc don’t know, the Ovi Store is Nokia's direct response to Apple's App Store, serving as a central content store for applications that can run on Nokia phones.

This was supposed to be a glorious day for mobile phone giant Nokia . The Finnish company got out-innovated by Apple a couple of years ago with the introduction and subsequent success of the iPhone and the iTunes App Store, and has been desperately trying to catch up with Cupertino’s disruptive initiatives ever since by launching a couple of new devices on one hand, and consolidating its software & services business on the other hand.

While users who entered through the Ovi Store device client encountered no issues, it appears that web users were experiencing a intermittent or extremely slow response.

I too went to Nokia Ovi Store website and have been trying to browse the selection of apps to select 10 that users should download to start off. I found that the store was down most of the time I was trying to snoop around, pages often didn’t load, and if they did they nearly always did extremely slowly. Despite the fact that I constantly needed to refresh and hope for pages to load, I figured that the service must be getting pounded from all the press it’s getting and was willing to forgive the slowness and regular downtime for the time being. But this has been going on for hours on end now, and there’s no sign of improvement.

To add insult to injury, i hear people with an Ovi account are unable to use their credentials for logging on to the new service, but that they are being told that there’s already a profile with their username when they attempt to register for a new account. That means Nokia is basically blocking registered users from using its new service at this point.

It seems that a large spike in traffic resulted in performance issues. An apology posted to the company's Ovi Blog confirmed the situation: "We apologize for any inconvenience this may have caused Ovi Store users." According to Nokia, it was able to make "intermittent performance improvements" by adding extra servers. Hopefully, everything will run smoothly in the next few days.