Stage 2 Specification For Voice Over LTE from VOLGA Forum now available

From our friend Martin Sauter's blog:

Regular readers of this blog probably remember that I'm a fan of Voice over LTE via GAN (VOLGA). For those who don't, have a look here on more details on why I think it has a good chance of becoming THE voice solution for LTE. It's amazing how fast the Volga-Forum is pushing out the specifications. In May, they published the stage 1 specification document, which contains a high level architecture and the requirements. Now only a month later, a first version of the stage 2 specification is available. Stage 2 specifications as per 3GPP contain a detailed architecture description and all procedures required from connecting to the network, originating and terminating calls, doing handovers, etc.

While their speed is incredible, maybe it should not be that surprising, because VOLGA is based on the already existing 3GPP GAN (Generic Access Network, i.e. GSM over Wi-Fi) specification. That's a good thing because that means that VOLGA could thus be developed quite quickly as it's likely that existing products can be modified instead of being designed from scratch. In addition, this should also mean that the first version of the standard is already quite mature as many areas were already verified during implementation and rollout of GAN in current networks.

I did a quick comparison between the two stage 2 specs and as I expected, many parts are very similar. While the GAN stage 2 specification has 126 pages, the current VOLGA stage 2 specification has 87 pages. This is probably because VOLGA is simpler than GAN. There are fewer handover procedures and most of the handover details are part of the 3GPP Single Radio Voice Call Continuity (SR-VCC) specification (for IMS) so they don't have to be included in the VOLGA spec. In addition to fewer handover scenarios, handovers are a bit more simple with LTE from a VOLGA perspective, as the network takes care of it unlike with GAN, where the mobile has to force the network into a handover. Also, there's no need to support the packet switched part of the network which also significantly lowers the complexity.

Well done, I am looking forward to the stage 3 specification which will contain the details on all messages and information elements used.

I blogged about VoLGA last month here.

LTE and 4G IPR

The other day I heard from Alex GeunHo Lee about his new blog related to 4G technologies IPR. Alex has got extensive experience in IPR and patent related issues and I am sure his blog will be very useful for everyone.

Couple of Alex's presentations are embedded below which I am sure many would find interesting.

LTE Essential Patents Landscape 2009 2Q

4G Key Technologies Patent Landscape 2Q 2009

You know you're Mobsessed when...

Tomi and friends are having fun on Twitter under #mobsessed. They are challenging everyone to complete the sentence "You know you are mobsessed if..". Here are few funny ones:

You know you're #mobsessed when you think text'n'drive is for amateurs. You google and drive.

You know you are #mobsessed if while on vacation,you value a place because it's 3G network coverage

you are #mobsessed if you and your wife squabble over the phone chargers (even though you have one in every room of your house)

You are #mobsessed when you think in sentences of 140 characters or less.

You know you are #mobsessed if you wake up your children in the morning by sending them SMS text messages,

You're #mobsessed when you go to toilet just so you can #tweet legally without being seen as #twitterholic in office

You know you're #mobsessed when you can't download new apps to your iPhone without deleting old ones.

You know you are #mobsessed when dropping your phone causes a near death experience. And you can't help singing when the phone still works.

If u carry 2 phones and are considering 3rd, u are #mobsessed

Check the search results on Twitter.

LTE UE Initial Signalling example

I have added initial signaling MSC for an LTE UE at the 3G4G website here. I havent yet managed to expand on the signalling details yet but it should be a good starting point for most people.

Santosh on his Wired n Wireless site has details on LTE Attach procedure which you may find interesting here. See here.

UK: Ofcom releases 3G coverage maps

Ofcom has just released (or as The Register puts it; found under the sofa) 3G coverage maps for UK. Its useful for people who dont live in big towns but planning to take out contracts on dongles/data services. They can now quickly check which operator to go for.

These 3G coverage maps by mobile operator were prepared in January 2009. They represent the area where we have assessed the mobile operators met a minimum coverage threshold set by Ofcom (see technical notes below). The shaded areas on the maps indicate areas where customers have the possibility of making and receiving a call outside over a 3G network (but with no guarantee of being able to do so). They do not indicate areas where customers are able to access higher data rate services.

All operators produce their own coverage indicators on their websites which are likely to provide more reliable guidance to network availability in any given area. The accuracy and detail of the maps are not to the same level as the mobile operators publish. These maps show UK-wide general coverage and are not suitable for zooming in to see specific locations i.e. a particular house or street. Also they are not suitable for assessing the quality or depth of coverage within the indicated areas (e.g. different operators may be able to offer better or worse data rate services or support a smaller or greater number of users).

You can see the PDF of the coverage maps here.

Wireless Cellular Security

Arvind, an old colleague recently spoke in ACM, Bangalore on the topic of Security. Here is his presentation:

Securing Wireless Cellular Systems

View more documents from ACMBangalore.

There are lots of interesting Questions and Answers. One interesting one is:

Does number portability mean that data within an AuC is compromised?

Not really. Number portability does not mean sensitive data from old AuC are transferred to the new AuC. The new operator will issue a new USIM which will have a new IMSI. Number portability only means that MSISDN is kept the same for others to call the mobile. The translation between MSISDN and IMSI is done at a national level register. Such a translation will identify the Home PLMN and the HLR that’s needs to be contacted for an incoming call.
That’s the theory and that’s how it should be done. It will be interesting to know how operators in India do this.

You can read all Q&A's here.

I wrote a tutorial on UMTS security many years back. Its available here.

Smart Grids: New Wireless Revolution

In the past two years, M2M (machine-to-machine) applications have become one of the most talked-about topics in the wireless industry. While M2M apps can be used for many purposes (such as smart homes, smart metering/electricity meter reading, fleet management, mobile workforce, automobile insurance and vending machines) and in many sectors (such as healthcare, agriculture, commercial, industrial, retail and utility), smart metering applications--also known as smart grids--present the biggest growth potential in the M2M market today. With many leading wireless service providers and utility companies jumping on the bandwagon and the growing support from states like Texas and California, M2M applications are set to become very successful in the coming years.


AT&T in March announced a new alternative for electric utility companies looking to provide the benefits of smart grid technology to the residential sector. AT&T and SmartSynch are for the first time providing utilities with a cost-effective solution by combining a new suite of service plans from AT&T designed specifically for machine to machine (M2M) communications with SmartSynch's smart grid solutions already deployed at more than 100 utilities throughout North America.

With this new solution from AT&T and SmartSynch, electric utility companies will now be able to concentrate on efficient electricity delivery rather than being distracted by building, maintaining, expanding and upgrading a communications network. This new solution offers a cost-effective point-to-point configuration model in which each meter communicates directly with the utility over the AT&T wireless network.

Smart grids combine "smart meters", wireless technology, sensors and software so customers and utilities can closely monitor energy use and cut back when the availability of electricity is stretched to its limit. The IP-based smart grid model ultimately helps consumers understand the economics of their consumption patterns so they can make intelligent decisions about their power consumption. The smart grid technology will also help to enhance reliability and energy efficiency, lower power-line losses and provide utilities with the ability to remotely automate service, providing cost-savings for consumers.

Key benefits of the point to point smart meter solution to utility companies include:

• improved speed of deployment over traditional meshed networks
• the simplicity of an open standard, IP-based network
• the ability to communicate directly with each meter.

How can T-Mobile, the fourth-largest cell phone carrier in the U.S., generate business in the face of dropping net additional subscribers and competition from low-cost cell phone companies? Get into the smart grid. Like AT&T and Verizon, T-Mobile is hoping to leverage its already built-out wireless networks to tap into the coming smart grid boom spurred by the stimulus package. On Thursday, T-Mobile plans to announce that it’s developing a durable SIM card that can be embedded in smart meters (as well as used for other industrial processes), and a new partnership with smart meter technology maker Echelon.

Mobile’s national director of Machine-to-Machine services, John Horn, told us that T-Mobile has been playing in the connected electric meter space for several years, including working with smart meter maker SmartSynch (AT&T has a deal with them, too), and he says the carrier has several utility pilot projects under way in the Pacific, Southwest and Midatlantic regions with an aggregate of “tens of millions” of smart meters. In some of those trials T-Mobile has been testing out its new smart meter SIM card, which is like the SIM card in your regular cell phone, but smaller — 5 by 6 millimeters — more durable and made of silicon, not plastic. Horn says the SIM, which can be connected to any of T-Mobile’s wireless networks, including 3G, can withstand the heat and environmental conditions of being outdoors in a smart meter much better than a standard SIM card.

One of the first smart meter makers to embed the new SIM is Echelon, which is also working with T-Mobile on a smart meter service that will run over T-Mobile’s wireless networks and, according to the companies, is significantly cheaper for utility customers. T-Mobile is just the latest phone company to drop its prices to attract utilities. AT&T and SmartSynch announced a similar deal last week. Horn said of T-Mobile’s smart grid price move: “We’ve broken historical pricing models.”

Network technologies including LTE, mobile WiMAX, WiFi and ZigBee potentially could be used for future smart grid applications. While it is still too soon to tell which technology is likely to become the big winner in this market, mobile WiMAX appears to have an edge over LTE due to mobile WiMAX's time-to-market advantage. Mobile WiMAX also has the advantage of being more reliable and secure than "pure" unlicensed technologies like WiFi. WiMAX can also count on support from leading companies like GE, Intel, Sprint Nextel, Clearwire, Motorola, Samsung and Google, among others.

Most importantly, WiMAX will enable carriers, utility companies and other key players to build open-standards based smart meters. Ultimately, through WiMAX, third parties will be able to develop many applications and devices, helping to reduce cost. With WiMAX chipsets currently running about $36, some observers believe that the cost could become as low as $8 or $6 in the next 18 months.

In the meantime, WiMAX-based smart meters are already available in the U.S. For instance, GE, in association with Intel and Grid Net software, has built one of the first WiMAX-based smart meters. Intel Capital and GE both invested in Grid Net in 2006. Companies competing with GE include companies like Trilliant, Itron, Silver Spring Networks (also one of GE's partners) and Landis & Gyr.

However, over time, LTE could become a valuable option for many companies involved in this space as LTE becomes widely adopted and prices associated with it start to come down. LTE's larger coverage capacity and ability to support a higher number of points should play a key role here. In our opinion, it will also become critical for LTE carriers to offer a decent revenue share with utility companies and other key players.

Although being a short-range technology, ZigBee could also have a role to play in the M2M apps space as several companies have expressed some interest in the technology. In fact, U.S.-based startup Tendril Networks is well positioned to become a pioneer in this space; the company, which teamed up with Itron and Landis & Gyr, has already developed a product called Tendril Residential Energy Ecosystem (TREE), compatible with various ZigBee-based devices to be used for smart grid apps inside homes.

Lastly, if fully secured, WiFi could also become a disruptor. WiFi-based smart grid apps appear to be gaining traction in the U.S. and Europe. For instance, the city of San Jose, in association with Echelon, is currently testing a whole smart streetlight network using WiFi-based smart grids set to be launched this summer. The system may receive federal stimulus money, and if it does the city plans to revamp the entire 65,000-light network, which would help reduce energy costs by 40 percent. That figure is consistent with the performance of two European cities: Milton Keynes in the United Kingdom and Olso in Norway, which have been implemented by Echelon.

From Ajit Jaokar's Open Gardens Blog:

While Telcos have historically rebelled against 'opening up', the US administration's emphasis on Open is creating huge opportunities for Telecoms and the Cloud

Broadband stimulus grants are tied to net neutrality rules, which means networks have to allow users to connect any device to the network

But this also leads to a huge opportunity because now Telecoms can extend their reach into the Smart Grid through MTM (machine to machine) applications which will generate a much higher number of network connections. These may have less ARPU (i.e. average revenue per user) but a greater number of actual connections with no need to subsidise devices. Hence, they could be profitable.

A smart grid starts with a 'smart meter' which is capable of two way communications and lets the user and provider manage electricity consumption in a more granular way. If the customer's power consumption can be captured in a granular manner, the provider can offer specials/ discounts to the customer. The added potential of smart grids arises from knowing data trends and also extend power management to other devices. These synergies fit well into LTE and home gateways and this explains with LTE and also explains Verizon's emphasis on Ipv6
The Verizon Itron partnership is an example of such a service and this service will be a part of Verizon's LTE deployment in the 700 MHz band for M2M apps.

The Zigbe alliance is also gaining traction as a result of this move by building wireless intelligence and capabilities into everyday devices and all this will lead to the 50 billion devices mark which suddenly does not sound so far away

On the services side, initiatives like Microsoft Hohm are being deployed and even if a utility isn't a part of Hohm, users can enter data directly which means that they can get more benefits the more they contribute to it.Google power meter is a similar initiative from Google.

The wider potential of this trend is discussed in an excellent article from Andrew GesmerEnergy Conservation From Zero to Sixty

Thus, Smart grids, LTE and the Cloud are a huge opportunity for the industry - but the privacy concerns with sensor networks and the Cloud will play an important part here.

Companies are building out the smart grid with various broadband technologies — cellular, WiFi, WiMAX — so why not good ol’ DSL? Smart grid sensor and software maker Current is touting a new smart grid partnership with DSL provider Qwest.

Current largely provides the sensors that monitor different conditions on the electrical network, like voltage and current, as well as the software that processes the sensor information for the utility customer. While Current is mostly focused on the distribution portion of the grid, it can also provide communication gear and sensors for smart meters and in-home gateways, which it is doing for Colorado utility Xcel Energy for its SmartGridCity rollout. Because Current needs to get its information back to the utility, it works with a number of companies that provide that network connection. The latest is Qwest, which Current started partnering with, and is currently working with, for Xcel Energy’s SmartGridCity plan (Qwest provides phone and broadband service in Colorado). The buildout of SmartGridCity is supposed to be completed soon, followed by an assessment of the network’s benefits.

What are the benefits of using DSL? Current’s senior vice president of business solutions, Mae Squier-Dow, says that because DSL is already widely available, using it speeds up the ability to deploy smart grid technology. And because the networks have already been built, she says, the option is more affordable for a utility than building out its own communications network. (Other companies argue that in the long run it’s cheaper to build and own the network). Since DSL is a proven technology, it can help smart grid projects gain access to stimulus funds meant for “shovel-ready” projects, Squier-Dow says.

DSL is also high-speed, so if utilities want to use the networks for more bandwidth-intensive services, they can. And DSL is based on Internet Protocol, so it can more easily connect with other IP-based networks and systems, which are ubiquitous. Ultimately DSL is a standard that’s been used for years, so utilities can be rest assured that the technology is highly reliable.

LTE activity gathering pace

Wireless internet access is going to be a better, richer experience than fixed link access Professor Michael Walker, group R&D director at Vodafone told Wireless 2.0 conference in Bristol, organised by Silicon South-West.

“People think wireless can’t compete with fixed link, but it can”, said Walker, pointing out that the 100Mbit/s of FTTH is the same as the theoretical maximum throughput of LTE.

“LTE capacity on 20MHz is an order of magnitude higher than HSPA,” said Walker. He said that, “in the first real field trials,” average downlink speeds of 15Mbit/s, with 4.5 spectral efficiency, were achieved. “Wimax takes three times more spectrum”, he said.

“We decided with LTE that we would make sure the technology works before we buy spectrum,” said Walker.

To that end, Vodafone has been working with China Mobile and Verizon to make sure LTE has compatible standards.

Walker regards talk of a killer app as silly for LTE as it was for 3G. “LTE is just about access,” he said.

He predicted the gradual relative demise of the person-to-person phone calls, referencing data that showed 11 times more wireless traffic is being generated by community chatting than by person-to-person calls.

Ericsson, one of the world’s leading suppliers of mobile phones and related network solutions, has warned that it could be 2012 before the first true next generation Mobile Broadband networks gain a good foothold in the UK. The deployment of Long Term Evolution (LTE) technology (aka - 4G), which could deliver download speeds of 150 to 1000Mbps, is being hampered by problems with releasing the needed 900Mhz spectrum.

Presently both O2 and Vodafone own some of the older 2G (900MHz) spectrum, which Ofcom is seeking to have redistributed to rival operators ( Orange , T-Mobile and Three (3) ). This could then be converted for use by 3G/4G voice and Mobile Broadband technologies, such as HSPA and LTE .

Nokia Siemens Networks (NSN), although providing WiMAX solutions for Taiwan operators, plans to launch commercialized LTE (Long Term Evolution) solutions in 2010, Mike Wang, NSN's general manager for Taiwan, Hong Kong and Macau.

NSN has already received LTE solution orders from Japan-based NTT DoCoMo, which is expected to start offering LTE-based services in 2010, Wang stated.

In addition, NSN has also landed orders for the installment of LTE trial networks for T-Mobile and Singapore-based service provider Mobile One, he added.

LTE-enabled chipsets are expected to hit the market starting in the second half of 2009, followed by LTE USB modems and network cards in 2010 and other LTE CPE such as handsets, PDAs, tablet PCs in 2012, Wang predicted.

Japan's DoCoMo is reported to be planning an investment of ¥ 343 billion (US$3.4 billion) for the investment, while KDDI and Softbank Mobile have budgeted ¥ 515 billion and ¥207.3 billion, respectively. According to the Nikkei newspaper, among the four, LTE services are forecast to attract around 36 million subscribers, with DoCoMo projecting 17.74 million LTE customers.

The total investment will top ¥1 trillion (US$10 billion)

DoCoMo, KDDI and Softbank Mobile expect roughly 30% of their existing customers to switch to 3.9G services. DoCoMo is also reported to be expecting to upgrade or deploy some 20,000 LTE enabled base stations by 2014. The network should cover 50% of the population and commercial services will start in 2010.

LTE provides downlink peak rates of at least 100Mbit/s, 50 Mbit/s in the uplink and RAN round-trip times of less than 10ms. Fujitsu recently announced that, in collaboration with NTT DoCoMo, they had successfully completed field testing for LTE, using 4x4 MIMO technology, which resulted in data transmission speeds in the range of 120 Mbps (using 10 MHz bandwidth) in Sapporo's urban environment.

NTT DOCOMO has selected Alcatel-Lucent' Ethernet transmission solution to provide the backhaul network of its Long Term Evolution (LTE) service. Financial terms were not disclosed.

Alcatel-Lucent said its packet optical gear will provide NTT DOCOMO with cost-effective and flexible Ethernet-based aggregation and transport from the base stations to the core network. Specifically, the Alcatel-Lucent solution, based on the 1850 Transport Service Switch (TSS) and its universal switching technology, will provide multipoint Ethernet connections between cell sites supported by strong operations, administration and maintenance capabilities, as well as carrier-class protection and network management.

China Mobile Ltd., recognizing that future growth of its 3G services is not yet certain, is looking to secure its future with a nearly parallel development of Long Term Evolution (LTE) capabilities, according to its annual report filed with the Securities and Exchange Commission (SEC) recently.

High on the list of limitations TD-SCDMA imposes are the availability, functionality, and price of terminals, and the support for international roaming. The latter particularly impacts China Mobile's high-end and business customers.

China Mobile remains committed to TD-SCDMA, but at the same time it's going all out to develop converged time division duplex (TDD) and frequency division duplex (FDD) products for LTE, the proto-4G wireless technology set to be deployed by mobile operators worldwide.
Developing a simultaneous LTE strategy will enable China Mobile to limit the time it is dependent on TD-SCDMA, and also help it counter the constraints it's currently experiencing as a result of the TD-SCDMA sector's limited ecosystem.

The Chinese vendors have labored too long under the market perception that they deliver low cost equipment, but can't do cutting edge. To fight this image and enhance their position among tier one carriers, Huawei and ZTE are throwing everything - including their huge credit lines for vendor financing - at gaining early LTE trials, which puts them in the spotlight even if commercial roll-outs are often two years or more away. The latest points go to ZTE, which has won field trial contracts with Telefónica in Spain and CSL in Hong Kong.

This comes shortly after Huawei highlighted its LTE deal with Netcom of Norway, and the Chinese duo are, early market estimates indicate, coming close to Ericsson in terms of their penetration of stage one LTE trials - and ahead of Alcatel-Lucent and Nokia Siemens.

Telefónica confirmed reports by Light Reading that ZTE's trial will take place in the third quarter. While success at the Spanish firm may not translate into meaningful revenue any time soon (and Ericsson has already conducted LTE trials with Telefónica too), it will still be a major boost for the vendor. It has not been as successful in getting tier one western carrier deals as its compatriot - although its overall wireless equipment market share grew at a similar rate to that of Huawei in the past 12 months, its base is far more concentrated on the lower margin developing markets.

By contrast with Telefónica, CSL is already a major customer for ZTE and one of the first commercial users of its software defined base station platform, which it is currently rolling out in an IP-based HSPA+ network across Hong Kong. In a recent interview with Telecoms.com, Tarek Robbiati, CEO of the Telstra subsidiary, said: "Further consolidation will come in the next three to five years. In the end there will be only three [infrastructure vendors] left, and two of them will be Chinese. The European vendors are just too slow."

With LTE firmly at the top of the hype curve in 2009, WiMAX is somewhat overshadowed in the headlines, but did make a strong impression at last week's CommunicAsia show in Singapore, highlighting how the technology has gained a higher profile in Asia than in Europe - because of the importance of the Taiwanese ODMs and vendors like Samsung, as well as a large number of deployments in countries like Japan, Vietnam, Korea and Taiwan.

Create your own LTE tests in 15 minutes with Anritsu’s RTD

Today we take an exclusive look in this blog inside Anritsu’s Rapid Test Designer (a.k.a. RTD) tool. RTD is a very powerful tool that can be used to design LTE tests for R&D purpose. RTD works in conjunction with Anritsu’s MD8430A. MD8430A has not very long back won the CTIA Emerging technology award.

For WCDMA/HSPA testing, Anritsu offered Protocol Test System (PTS) for R&D purpose. For LTE the basic tool is the RTD. The advantage of RTD as opposed to earlier generation PTS is that RTD is GUI based development environment that can speed up development and very little knowledge of test script development environment like TTCN-2 and TTCN-3 is required.

The RTD is a software tool that sits on top of a control PC. It controls the Signalling Tester (hardware) MD8430A. The diagram above shows the setup and connections of different components. The hardware (MD8430A) simulates Layer 1 (PHY), MAC, RLC and PDCP. The software (RTD) is used to simulate RRC and NAS.

When the tool starts up you are offered typical options as in case of any software. Once you have clicked on new test and provided it with a name, you are up and creating your own scenario.

The simple procedures already have a name defined but you can start giving meaningful names to complex procedures. Each name signifies the action it will be performing. For example Cell Configuration will be used initially to configure the parameters of the cell.

Clicking on the Cell Configuration will provide you with the possible options that can be used to configure the cells like the SFN Offsets, etc. All the channels that are necessary for a cell can be configured here.

Here is my attempt to randomly create something :)

And try sending some message like RRC Connection release. Didn’t quite work because it’s not in the right sequence but just shows the ease with which things can be done.

This is run time result of one of the test cases.

It may take few hours to get the hang of RTD, but once you understand how it works, you can start creating your own tests and scenarios at full speed. There are also example procedures available to get you started ;)

"The MD8430A is being used by LTE chipset manufacturers to ensure the quality of their products, speed time to market, and reduce design and production test costs." - Wade Hulon, Vice President and General Manager of Anritsu Company, Americas Sales Region.

You can learn more about MD8430A and RTD by following the links below:

• http://www.us.anritsu.com/downloads/files/MD8430A_EL1101.pdf
• http://www.eu.anritsu.com/files/MD8430A_LTE_E2101.pdf

Note: All the information mentioned in this post is my personal view and does not represent Anritsu's official views. Also if you manage to take few more minutes to create your own test then please do not blame me ;)

R&S bidding for LTE leadership

Free online LTE Tutorial is available at IEEE Communications Society Website, courtesy of Rohde & Schwarz. You can view the tutorial here.

Not long back, I saw R&S demo of CMW-500 with the LG UE at the LTE World Summit. R&S has also verified ETSI 3GPP LTE TTCN-3 test cases with Qasara and has shown successful interoperability testing between Qasara’s Virtual UE and Rohde & Schwarz's 3GPP LTE Virtual Tester.

There is also a LTE TDD Technology Overview available to download from their website here.