IMS Deployment and Future Strategy

A very interesting post by Christophe Gourraud in The IMS Lantern. If you are even remotely interested in IMS then you should read the post here.

Solving the LTE voice dilemma

Continuing the discussion from LTE World Summit, this is something that has been discussed in the past by myself and other blogs as well. We know that there is no out of the box solution for voice calls in Release 8 but there are some solutions that are being standardised for this problem. Dr. Howard Benn, Director of Cellular Standards, Motorola Mobile Devices gave an interesting presentation on this topic titled, "Voice –how to talk over LTE". Here is the summary of his presentation along with some more information:
As we know, IMS was introduced in Rel 5 but even till today, there has been no major IMS rollouts. There are some operators working on deploying the IMS solution but in reality its not been as successful as it should have been. If IMS is available then the problem of voice call on LTE goes away. The problem can be solved using Voice Call Continuity or VCC. Infact there is a bunch of specifications on IMS Centralized Services (ICS) and network Centric VCC for solving this and other similar problems.

So with IMS not being available, the first alternative for this problem is Circuit Switched Fallack (CSFB). In this, as can be seen from the MSC above, the user is attached to an LTE network. MSC can send Paging to the UE and if the user accepts the voice call then he is handed over to 2G/3G network. The big problem with this approach is additional time required to establish the voice call and the PS services might get disrupted, depending on how its handled.

The second solution is to have a Generic Access Network (GAN... previously known as UMA) based solution. This is similar solution to the ones used by some Femtocells. This would mean that the UE's would require GAN chipsets and GAN is known to be power hungry so it can impact the battery life significantly.

China Mobile's, Bill Huang in a recent interview mentioned that “We could carry voice over UMA” and “We will have an LTE network that supports voice…”. He was referring to this approach mentioned above.

Finally there are always proprietary options like Skype that can be used along with the data services to solve the voice problem.

Infact a service like Vonage, modified for mobiles, can solve this problem easily. You can connect a VoIP client from your phone or device to Vonage and you are given a landline number that you can pass to others. When calls are received on this number, the client in the mobile rings and you answer the call normally.

Nick Yamasaki from KDDI mentioned that KDDI will roll out LTE with CS fallback option for voice initially but then SRVCC (Single Radio VCC) solution will be adopted in future.

NEC and Ubiquisys to help deploy first IMS based Femtocell Solution

Japanese operator SoftBank is to score a world first in January, when it becomes the first service provider to launch 3G femtocells in a commercial capacity.

SoftBank, Japan's third placed carrier behind NTT DoCoMo and KDDI, said it will offer 3G femtos from January 2009 using kit from UK-based Ubiquisys and a supporting IMS core from NEC.

According to Unstrung:

Japan's Softbank Mobile Corp. is still trying to get the national regulator to change a quirky policy that could thwart its plan for a large-scale femtocell deployment, according to an industry source. In Japan, only a qualified engineer can install a base station, and that rule applies to the small, low-power base stations, too.

Femtocells are supposed to be "zero touch" and easily installed by the users themselves. So, a regulation that mandates sending out an engineer to plug in each and every home access point would kill an operator's femto business case.

The Japanese policy is expected to be changed by the end of the year, which wouldn’t be too soon for Softbank. According to our source, the operator has already installed 20,000 devices, has chosen an NEC Corp. solution -- which uses Ubiquisys Ltd's femtocell -- and is also checking out equipment from Huawei Technologies Co. Ltd. Softbank isn't quite ready for a mass market deployment because there are still some technical issues, according to the industry source.

Meantime, NTT DoCoMo Inc. said last week that it was going to use the new HSPA version of Mitsubishi Corp. femtocell for its Home Area service.

There have been couple of so called Femtocell launches already namely T-Mobile Hotspot@ and Sprints CDMA Femtocell but they are not really Femtocells because they just provide an extension for voice services and no other type of services.

The Femtocells are called ZAPs (Zonegate Access Points) and Japanese customers will be able to get their hands on them from Jan 2009.

Next Generation All-IP Telecom Networks: Quality of Service Challenges and Is...

There is an Interesting tutorial on Next generation All IP Networks from Google on Youtube. Unfortunately they have not allowed sharing of that but you can see that on youtube:

http://www.youtube.com/watch?v=FC4E946i6aE

NRS, ENUM and NGN

The way most of mobile savvy people work is that they have bundles of free minutes on their mobile which they use for calling people locally/nationally and then they have VoIP based clients like Skype they use for calling people on similar services locally/nationally/internationally. There is a constant juggle between Mobile numbers and VoIP numbers. What if we were able to use our number with VoIP client so regardless of whom you are calling, if they have a similar VoIP service on their side, you get free call and if they dont have this VoIP client then you use your inclusive minutes or get charged. ENUM will be able to solve this.

According to a Yankee Group report titled "ENUM Will Be Reinvented as a Strategic NGN Element", In spite of its early struggles, ENUM, short for Electronic Numbering or Telephone Number Mapping, is well positioned to provide a fundamental underpinning of the Anywhere Network™ as it relates to the efficient routing of any IP-based service across operator domains. It is in this new role that ENUM evolves from its rather meager beginnings to a strategic role in the transition to IP.

I wrote about ENUM sometime back as that was mentioned as magical entity in one of the conferences. Since then I have managed to find the Nominet presentation which was discussed in the conference. Infact there was a conference in London on ENUM organised by Nominet. If you are not clear about ENUM from my earlier Blog then please check Technology Inside Blog here.

We can discuss again here, why ENUM is important:

Imagine the NHS has 500 telephone numbers that it operates as 0800 freephone numbers to allow customer (patients) to contact various local departments. The cost of each minute of every call is borne by the NHS so ultimately by the British taxpayer. Now the NHS also has VoIP connectivity and decides to advertise their 0800 numbers through DNS using ENUM. Subsequently, every time someone using VoIP decides to call any of those 0800 numbers their VoIP provider will find the 0800 number in the ENUM DNS listings for the NHS and will connect the caller to the medical department using VoIP alone - at no cost to either party (usually).

Siemens have a very good presentation that shows different uses of ENUM.

Clearly with this approach there is scope for financial savings. That said, there remains considerable work needed to achieve even this small goal, let alone the potential options further down the road.

In case you were wondering, ENUM is an international standard being implemented by individual countries separately through their respective Governments. The UK Government, through regulator OFCOM, has assigned the design, implementation and ongoing administration of the project to UKEC who, in turn, have contracted much of the work to Nominet. Nominet administer and maintain the .uk gTLD - when you buy any domain ending .uk it is ultimately sold by Nominet although almost always through a reseller (”registrar”) like GoDaddy.

GSMA and NeuStar have been working with leading operators to provide a standards-based solution to this problem. This solution is the Number Resolution Service, or NRS.

NRS is a GSMA Managed Service operated by NeuStar. The service facilitates IP interoperability by translating telephone numbers to IP-based addresses. Interoperability is particularly important in facilitating the uptake of emerging services such as MMS, IMS and Packet Voice.

Based on Carrier ENUM, NRS is available to mobile operators, fixed network operators, and related service providers. The service is currently being piloted with a number of operators, with commercial availability scheduled for the autumn of 2008.

As next generation IP-based services proliferate, operators can utilise NRS to position new services behind the telephone number already used by subscribers. Whenever a telephone number is used to identify an end user, the NRS service will facilitate the discovery of URI containing information specific to the service being provided.

NRS is provided as an off the shelf managed service, interoperable on a global basis, providing all the facilities and features necessary to implement an operator’s interconnect policies. Pricing is based on a cost effective “pay as you go” model with no up front capital investment required. NRS thus helps lower the entry barrier for new services and promotes innovation by simplifying the product development and implementation process.

ENUM is going to be hated by the CPs because it will lower their per minute revenue which they are getting at the moment but they it is definitely going to provide new opportunities (and competetion). At the same time the customers will love it because they will get loads of free calls and dont have to worry too much about installing different VoIP clients on their phones. At present it is still in the initial stages with everyone waiting for others to adopt it first but ENUM is here to stay.

Abbreviations:

• ENUM - tElephone NUmber Mapping (I have also seen Electronic NUMbering)
• CP - Communications Provider
• SBC - Session Border Controller
• NHS - National Health Service (in UK)
• NRS - Number Resolution Service
• GSMA - GSM Association

IMS: Reality check

IMS is another technology not doing too well at present. I came across this report by Yankee group, "IMS Market Update: The Honeymoon Is Over, Now What?" and it answers some of the questions why IMS is not as popular as people expected it to be 3-4 years back.

Some of the promises made by IMS were:

• New IMS based apps, hence increased ARPU
• Simplified network design, hence lower OPEX
• Platform for killer services
• Components interchangeable
• Plug and Play environment for access networks

But the reason IMS has not found success is because:

• IMS Standards are in flux
• Everything is quite complex and not very clear
• OSS/BSS integration is very complicated

An article in Cable 360 has some up to date market details:

Based on a report completed in January by ABI Research, Ericsson is market leader in providing IMS infrastructure followed by Alcatel-Lucent and Nokia Siemens. The other vendors in this ranking include Motorola (4), Huawei Technologies (5), Cisco Systems (6), Nortel Networks (7), Acme Packet (8), Thomson (9) and Tekelec (10).

Bundling is increasingly the way that IMS is sold. "Huawei combined a lot of their wireless offerings with IMS," ABI Senior Research Analyst, Nadine Manjaro said. "Whatever their contacts were, they had an IMS element."

"Previously (IMS) was more fixed," she said. "IMS is difficult to integrate. (So) one trend is combining IMS with infrastructure and 3G deployment and managed services," she said.
Increasingly critical to versions 6, 7 and 8 of the Third Generation Partnership Project (3GPP), IMS will become more tightly linked with mobile technologies, Manjaro predicted. The overall context remains telephony-focused.

"You see highly voice-over-IP related deployments of IMS globally," she said.

My understanding is that with the tight squeeze on financial market, everyone is trying to spend as less as they can. This means that end users are being shy of the extra features and services as long as it costs them and the operators are being shy of investing in new technologies or upgrading their infrastructure. Even though investment on IMS could be significant, it can provide long term benefits which may distinguish an operator from others and provide the cutting edge.

Another thing is that the IMS technologists (and why just them, others as well) should ensure that all the technical problems are ironed out and start promoting the technology to everyone. People ae already confused enough about HSDPA and 4G and we need to prepare them to look forward to IMS.

LTE, IMS and Voice calls!

Picked this up from Martin's Blog. One of the things that has been left undefined are the end user applications. Unlike GSM and 3G+ where AMR RAB's has been defined for CS voice calls, there is no provision in LTE. In fact we know that CS domain is completely absent and only IP based PS domain is present. It has been assumed that IMS will be de-facto present along with LTE and the architecture rightly defines so but there is nothing stopping LTE being deployed without IMS. The following is from Martin's Blog:

LTE requires the IP Multimedia Subsystem (IMS) for voice calls. So what will happen to LTE if IMS doesn't take off? I know, many in the industry believe even asking such a question is close to heresy but who can promisse today that IMS will be a success?

The trouble with IMS and to some extent with mobile VoIP is not that it's a young technology, standardization has been going on for many years and books about it are going into their third edition. However, there are still no IMS systems out there today that have come out of the trial phase, and I have yet to see a mobile device with an IMS client which is nicely integrated and simply works. Also, the IMS standard is getting more complicated by the day which doesn't make life easier. Another main issue with VoIP and consequently IMS is power consumption. I use VoIP over Wifi a lot on my Nokia N95 and can nicely observe how the phone slightly heats up during a long phone call. Also the non-IMS but SIP compliant Nokia VoIP client in the phone, which by the way is nicely integrated, sends keep alive messages to the SIP server in the network several times a minute. This is necessary mainly due to Network Address Translation (NAT). While this doesn't require a lot of power over Wifi, power consumption skyrockets as soon as I configure VoIP for use over 3G. I can almost watch the power level of the battery drop as the network now constantly keeps a communication channel open to the device. So there are two problems here: VoIP calls cause a much higher processor load during a call, i.e. the VoIP talk time is much shorter than the 2G or 3G talk time and the standby time is significantly reduced. Add to that the missing handover capability to 2G and 3G networks (yes, I know there is VCC in theory) and you have a prefect package for a very bad user experience.

So the big question is if all of these things can be fixed, say over the next 5 years!? I have my doubts... If not, then LTE has a big problem. Will network operators accept running GSM or HSPA alongside LTE until the problems are fixed? The choice is this and accepting that LTE is for Internet access and some niche VoIP applications on devices such as notebooks or to decide sticking to HSPA(+) until things are fixed.

In case LTE is deployed and LTE - IMS devices are not ready it's likely that a device can't be attached to several radio networks simultaneously. So how do you inform a device attached to LTE about an incoming voice call? It looks like the people in standards bodies are looking at different solutions:

• Send a paging message for an incoming circuit switched voice call via LTE to the device. You can do this on the IP layer or on the radio network signalling layer. The device them switches radio technologies and accepts the call.
• Some people have started thinking about extending LTE with a circuit switching emulation.

This could be handled on the lower layers of the protocol stack and the software on top would not notice if the call uses GSM, UMTS or LTE. This one is easier said than done because I don't think this concept will fly without a seamless handover to a 2G or 3G network. If such a solution ever gets into mobile phones, it would make life for IMS even harder. Who would need it then?

Are there any other initiatives I have missed so far to fix the LTE voice issue?

Dean Bubley in his Disruptive Wireless Blog has interesting analysis on this topic as well:

My view is that operators should either work with Skype, Truphone, fring et al – or compete head-to-head with them using their own pre-standard mobile VoIP implementations. I still believe this is a good route to VoIPo3G, especially for operators that are already moving to VoIP in their fixed networks, or which are early deployers of IMS or other IP-NGN architectures. Blocking VoIP it not a viable option in competitive markets - as evidenced by the increasing trend towards openness that's been seen in recent weeks.

But interestingly, another ‘flavour’ of mobile VoIPo3G is now emerging as an alternative for mobile operators – Circuit Switched Voice over HSPA, as an early specification within 3GPP’s Release 8 generation of standards. This was just starting to evolve seriously when I published the report in November, and is mentioned in the comments on this post of mine. And it now seems to be moving fast. In the last week, two of the largest ‘'movers and shakers' in mobile technology - from both handset and network sides - have talked up this approach to me unprompted. And I’m in agreement that it’s undoubtedly going to be important.

Basically, CS voice over HSPA takes the ordinary mobile circuit voice service, using ordinary diallers on the phone, and circuit core switches in the network... and tunnels it over an underlying IP bearer. So the application isn't VoIP, but ordinary circuit telephony, but the wireless transport (down in the guts of the phone) is IP.

In other words, it's "Mobile Circuit Telephony over IP"

In fact, we've all heard this concept before. It is an almost direct HSPA equivalent of UMA’s voice over WiFi. In both cases, there are benefits for operator voice calls, derived from the nature of the radio IP bearer: cost in WiFi’s case as it’s unlicenced spectrum, and the efficiencies of new packet transmission techniques in HSUPA and beyond. And in both cases, it’s not necessary for the operator to have already deployed IMS, VCC and so forth – they can reuse their existing core networks, and get away with less messing-around at the handset application layer. [I’m not sure yet whether the IP tunnel uses a similar IPsec approach to UMA, and could use a similar gateway, or if it’s entirely new]. The downside is that this isn’t a next-gen IP voice service in terms of application capability – it’s voice 1.0 transported over network 3.5.

There are also various reasons why I'm more positive on CS over HSPA than I am about WiFi-UMA.

It's a matter of semantics whether you treat CS Voice over HSPA and UMA as 'true' wireless VoIP. Both are using classic circuit signalling, rather than SIP or proprietary protocols like Skype. Neither are as easy to use as "full VoIP" as the basis of innovative applications like voice mashups.

The interesting thing to me is that the industry is starting to polarise into different points of view on this issue. Ericsson remains a staunch MMTel advocate, driven by its desire to push IMS as the main future application layer. But other major players seem to be edging towards a CS over HS worldview, albeit with a hedge around naked-SIP VoIP.

So… taken together, the various types of VoIPo3G are going to be:

• Over-the-top independent VoIP (Skype, Truphone, IP-PBX etc) with a dedicated client on the handset or PC
• CS voice over HSPA, using the ordinary circuit voice app plus some lower-level IP ‘plumbing’.
• IMS MMTel – needing a full IMS client on the device
• Other IMS or standards-based voice apps like PoC or perhaps a standalone SIP VoIP server plugged into the IMS application layer
• Standalone operator softswitch-based VoIP connecting to a (probably) SIP client on the handset.
• Partnerships or mashups of the above.

Messy and diverse, in other words. And all of these have different use cases, different pro’s and con’s, different requirements in terms of user behaviour, cost and so on.

But the bottom line is that with the addition of CS Voice over HSPA, my top-level VoIPo3G predictions are still looking feasible, although some of the fancier web- or application-based VoIP capabilities will be trickier to exploit by the operators choosing that approach.

I have to admit that I havent looked into this area at all and cannot comment on which direction things will move. One thing that I can definitely say from my experience is that the initial movers, if successful, will set the direction for others to follow and may be eventual winners.

IMS to succeed by serving LTE

IMS (IP Multimedia Subsystems) has been around for some time, and many infrastructure vendors have invested heavily in developing IMS capabilities, solutions and products. But market acceptance has been slower than expected. Now, with the 4G standards LTE (Long Term Evolution) and WiMAX taking shape, the IMS platform has been given a new role and a niche that will carry it a considerable distance into the future.

That is because some elements of IMS such as the Home Subscriber Server (HSS) and the Policy and Charging Rule Function (PCRF) are also key components in the LTE core architecture. Similar elements are also defined in WiMAX. These elements are required to enable the end-to-end QoS and dynamic charging capabilities required for the next generation of mobile data services.

“IMS, which enables the rapid creation and deployment of new services and applications, was rather slow to take off because operators weren’t quite sure how they were going to use it,” says ABI Research senior analyst Nadine Manjaro. “They struggled to find a business case for it. Now, the FCC in the United States has declared that winners of 700MHz spectrum must meet open application and device criteria. Verizon won most of that band in the recent auction, and will use it for LTE. Verizon launched its Open Development Initiative (ODI) based on IMS architecture called ‘Advance to IMS’ in March 2008. This interface for applications and devices will enable the openness that the FCC requires.”

Many operators and vendors are now moving to an open applications architecture: Sprint has mentioned it in reference to its application strategy and uses IMS as the base architecture for its High Performance Push to Talk (HPPTT) network scheduled to launch in June 2008. Nokia mentioned open devices and applications as a key initiative in its migration strategy. IMS will help to ease the transition to open development, and will be a fundamental part of future LTE and WiMAX networks.

More on this available available in this paper here.

Security Upgrade from Release 7

For those familiar with the 3G Security (Ciphering + Integrity) architecture will know this well that there is only one Integrity algorithm (UIA1) defined and it is mandatory. On the other hand there are two ciphering algorithms (UEA0 and UEA1) defined. UEA0 in reality means no Ciphering ;). UIA1 and UEA1 are both based on Kasumi algorithm. UEA1 is f8 and UIA1 is f9 algorithms of Kasumi. (Please feel free to correct my terminology if you think its wrong).

From Release 7 there are some additional provisions made for increasing the security.

First lets talk about GSM. Initially only a5_1 and a5_2 algorithms were defined for GSM. They have not been compromised till date and are still secure. Still some new algorithms have been defined to make sure there is a backup if they are ever compromised. a5_3, a5_5 and a5_8 have been defined for GSM/GPRS and GEA3 defined for EDGE.

For UMTS, UEA2 and UIA2 have been defined. They are based on 'Snow 3G' algorithm. Kasumi is a 'blockcipher' algorithm whereas Snow 3G is 'streamcipher'. The interesting thing as far as I understand is that even though this is defined and mandatory for UEs and N/w from Rel7, it wont be used but will only serve as backup. More on this topic can be learnt here.

More detailed information on UIA2 and UEA2 is available here.

There are some enhancements coming in the SIM as well. At present all the Keys are 128bits but there should be a provision that in future, 256 bits can be used.

There are some extensive overhauling of IMS security as well but I havent managed to get a good understanding of that yet.

All the reports from the 3rd ETSI Security Workshop held on Jan 15-16 2008 are available here.

Whats this ENUM business

In the recently concluded Unified Communications 08, one of the presentations was titled "The Magic of ENUM". I didnt get a chance to attend that but tried to dig out what this magical thing called ENUM is.

The following is from The IP Multimedia Subsystem by Travis Russel:

In the SIP domain, subscription addresses use the form of a Universal Resource Identifier (URI). This is analogous with the Universal Resource Locators (URLs) we use to reach Web sites on the Internet, but they are assigned to subscriptions for reaching individual subscribers. It is the concept of the URI that makes communications models in the IMS unique. The ability to reach a subscriber based on these very personal identities rather than numbers, and to apply these addresses to all forms of communications, is the purposeof the SIP protocol within the IMS.

A URI can take two forms. A SIP URI uses the same form as an e-mail address, consisting of username@domain. The first part of the address is typically the username of the subscriber, while the last part is the domain name of the network provider where the subscription resides. The last part of the domain name (.com, .org, etc.) defines the type of organization according to Internet rules. SIP also supports addresses in the form of telephone numbers, referred to as TEL URIs. A TEL URI uses the same form as a SIP URI, substituting the telephone number for the user name. These are used most commonly when a call is originated in a non-SIP domain, or when a call is being placed to a non-SIP network (such as a call from the IMS to a wireline subscriber in the PSTN). The TEL URI is a good example of interoperability between legacy PSTN and IMS.Since legacy networks will continue to support the use of telephone numbers for some time to come, there remains a need to translate these telephone numbers into public identities for use within the IMS.

The actual conversion process is provided through a function known as ENUM. This function translates an E.164 telephone number into a SIP or TEL URI. The ENUM function does not translate the identity into an IP address, however. This remains the function of the Domain Name Server (DNS). We will talk more about these functions later. Eventually, TEL URIs may disappear completely as we become more and more accustomed to using SIP URIs for all communications. This is still a long way off, however, and something we may not see for decades.



For more information see the following book:

You may also be interested in the following presentations:

• ENUM Variants by Jim McEachern, Nortel
• ENUM will it pay? by Richard Shockey
  

IMS rolling on! Quiet and Steady

IP Multimedia Subsystem (IMS) is expected to provide mobile telephone operators with a forecasted $300 billion in extra revenue over the next five years, according to a new study from ABI Research. Major operators such as Sprint, Verizon and British Telecom (BT) will increasingly deploy IMS across their networks in a quickening tempo starting this year.

“Until recently IMS was mainly the province of fixed-line operators,” says senior analyst Nadine Manjaro, “but now it is essential to the success of mobile and fixed operators who are losing revenue from traditional sources. IMS enables rapid development and deployment of new services.”

Some firms – notably Verizon and BT – are facilitating this process by offering an open IMS interface allowing third-party developers easy access, as a way of ensuring a flow of new applications. This means faster testing and deployment of services, which will be critical to their success.

“Operators are forced to look at IMS and similar solutions because they need to start generating more revenue,” notes Manjaro. “With recent moves by Sprint, Verizon and AT&T to offer less profitable flat rate services as a way to fight subscriber churn, that need becomes more acute.”

One impediment to IMS’s success in the past has been the difficulty of proving the business case for it. But Manjaro suggests that planners were incorrectly considering IMS as a service rather than a platform. In fact IMS supports multiple services, and it takes several of them to make a valid business case. To use the hackneyed phrase, there has been a paradigm shift in operators’ strategic thinking.

The major remaining challenge for operators is to integrate IMS without seriously disrupting existing services. That need is being met by the major infrastructure vendors such as Ericsson, Alcatel, and Nokia-Siemens, which have been packaging IMS (at additional cost) with the network upgrades they provide to operators. Manjaro points out that, “It’s easier to quantify the opportunity for operators because you can look at it in terms of potential revenue. It’s more difficult with regard to vendors, because they’ve been bundling it with the air interface, the base station, the architecture upgrade.”

In other new IMS pulse-taking – Forward Concepts’ ‘Femtocells: The Emerging Solution for Fixed Mobile Convergence’ report – it’s predicted that IMS-powered femtocells will capture the dominant fixed-mobile convergence (FMC) market share by 2010. The argument here is that Unlicensed Mobile Access (UMA) is a transitional technology and cellular carriers will ultimately transition to IMS-enabled femtocells. Forward Concepts calculates that global femtocell equipment revenues will grow at a CAGR of 126% from 2008 to hit US$4.9bn in 2012. Western Europe will be the largest market, driving 32% of the revenue, followed by North America with a 22% share.

Check my old blog on IMS and UMA.

The IMS (IP Multimedia Subsystem) and the NGN (Next Generation Networks) Forums announced recently the successful completion of interoperability testing at the IMS Forum Plugfest 4 and plans for the NGN Plugfest 5. Plugfest 5, scheduled for June 2008 at the University of New Hampshire InterOperability Lab (UNH-IOL), will test consumer and enterprise M-play interoperability.

The IMS and NGN Forums are dedicated to interoperability and certification of M-play, mobile multimedia services, and applications for wireless, wireline, and cable broadband over IP networks.

The IMS Forum's Plugfest 4, held at the UNH-IOL Feb 25 - 29, was the latest in a series of events designed to deliver IMS and NGN interoperability and certification. Participating companies tested a number of leading technologies and services for interoperability, including triple play, VoIP (voice over IP), fixed mobile convergence (FMC) from multiple vendors, test and measurement equipments, SIP (session initiation protocol), class-5 features (voicemail, etc), Diameter IMS stacks, and instant messaging with presence support. Plugfest 4 was the first successful IMS call between mobile UE (user equipment) devices and core network elements P-CSCF servers, S-CSCF, and HSS, all from separate vendors.

Plugfest 4 was expanded to include billing interfaces for charging for IMS services. Tests included an IMS-compliant charging/billing system working with multiple network configurations, as well as interoperability of operational support systems and business support systems (OSS/BSS). This is a major milestone since the charging/billing systems are a major component for network operators to deploy IMS.

More than 15 companies participated in IMS Plugfest 4, including Intel as a platinum sponsor, HP, Amdocs, Acision, Alpha Networks, Aricent, Data Connection Ltd., Empirix, Mavenir Systems, Mu Security, NextPoint Networks, Radvision, Shenick Network Systems, Sonus Networks, Starent Networks, Tekelec, and UNH-IOL. PulverMedia and IMS Magazine served as media sponsors.

Finally, Ericsson has announced an agreement with Beijing Netcom, a branch of China Netcom, to provide the company with a Command Supporting System based on Ericsson's IMS solution for the Beijing Olympic Games.

China Netcom is the official fixed-telecom service partner for the Beijing 2008 Olympic Games. Under the agreement, Ericsson will be the sole supplier and systems integrator for an IMS (IP Multimedia Subsystem) platform to enable personal multimedia communication.

Ericsson's IMS solution enables the convergence of data, speech and network technology over an IP-based infrastructure. It supports fast and efficient management and coordination of value-added services, including voice, text, pictures and video, providing end users with a personalized, richer communications experience.

Deployment and systems integration has started and is set to be completed by March 2008. It will span the six Olympic Games cities in China.

The agreement is an extension of a contract signed between Ericsson and Beijing Netcom in April 2007 to build the first commercial IMS network in China.

Beijing Netcom says: "As an official partner for the 2008 Beijing Olympics, this agreement emphasizes our commitment to providing telecom-quality IP multimedia services that combine voice, data, audio and video. This move will bring an enhanced communications experience to users in Beijing and across other Olympic cities."

Mats H. Olsson, President of Ericsson Greater China, says: "Ericsson is extremely proud to build on its longstanding relationship to provide Beijing Netcom with the first IMS-based multimedia service for the 2008 Olympic Games. This contract confirms that IMS has come of age, enabling volume deployment supporting multimedia capabilities within the fixed-network operator's service."

Ericsson is the world's leading provider of technology and services to telecom operators. The market leader in 2G and 3G mobile technologies, Ericsson supplies communications services and manages networks that serve more than 185 million subscribers. The company's portfolio comprises mobile and fixed network infrastructure, and broadband and multimedia solutions for operators, enterprises and developers. The Sony Ericsson joint venture provides consumers with feature-rich personal mobile devices.

IMS Service: An Insight

Brilliant article from 'The IMS Lantern':

An IMS service is a service that makes use of SIP and the IMS either centrally or marginally.

SIP itself and even more, the combination of SIP with other protocols can give birth to a flurry of new services, some of them implemented on IMS.

The ability of SIP to combine various existing services of different types (communication, data, content, applications) can give birth to a new user experience, which is by itself a new service. This is an important matter to consider when comparing SIP with more purpose-centric protocols.

These new services can reach a huge community covering all the continents, all types of access technologies and spreading between telco domains, other business domains, and the Internet, possibly redefining the definitions of these domains.

IMS and SOA (Service oriented Architecture) are not alternative architectures to deliver new services. They should rather be seen as building blocks permitting to create a new and more powerful service architecture called UOA (User Oriented Architecture).

This draws a potential future world, in which there might be a little bit of SIP everywhere, and consequently a a good potential for IMS to fit as a particular SIP service architecture deployed by telco operators.

However, history shows that the best technologies do not always prevail. In a possible future, the potential of SIP as a service control protocol used in different architectures including IMS, and/or IMS as a service architecture augmenting the intrinsic capabilities of SIP, might eventually fail. Conversely, would SIP and/or IMS be only used at a fraction of their potential (e.g. for VoIP and a limited set of additional services), they could still be a success.

CAMEL and IMS

Source: CAMEL: Intelligent Networks for the GSM, GPRS and UMTS Network

CAMEL is to CS domain what IMS is to IP domain. Since we are all moving towards IMS, eventually CAMEL would become obsolete. Another important thing with IMS is that it is access independent and defined for wireless as well as wireline technologies.

IMS will take some time to be implemented and in the meantime CAMEL and IMS will co-exist. In the meantime operators may use CAMEL to control IMS to take advantage of the technology they have heavily invested in and have tested for some years.

CAMEL control of IP multimedia calls forms a bridge between the CS mobile network and the IP multimedia network. The IMS is the IP-based communication system for mobile networks. Although IMS, which was introduced in 3GPP release Rel-5, is specified for the mobile network,
it may also be used for wireline networks. In fact, the nature of IMS facilitates arbitrary access methods to be used.

Some Useful Specs as follows:

• 22.228: Service requirements for the IMS
• 22.250: IP multimedia subsystem group management
• 22.340: IP multimedia subsystem messaging
• 23.228: IP multimedia subsystem
• 23.278: CAMEL – IP multimedia system interworking
• 24.228: Signalling flows for the IP multimedia call control based on session initiation protocol and session description protocol (discontinued after Rel-5)
• 24.229: Internet protocol multimedia call control protocol based on session initiation protocol and session description protocol
• 29.228: IP multimedia subsystem Cx and Dx interfaces; signalling flows and message contents
• 29.229: Cx and Dx interfaces based on the diameter protocol; protocol details
• 29.278: CAMEL application part specification for IP multimedia subsystems

Further Reading: CAMEL: Intelligent Networks for the GSM, GPRS and UMTS Network by Rogier Noldus

IMS client

This is a reponse to the question 'What exactly constitutes an IMS Client' that was posted by various people on ForumOxford.

The main components of an IMS client, consist of the following:

OS functions:

IMS specified protocols, such as SIP, SDP, XCAP, RTP etc. that are essential for IMS based services

IMS core functions, such as registration,session control, authentication , authorization, accounting, QoS etc.

IMS enablers for services, such as presence, IM, location, PoC etc.

API support:

IMS core APIs for the standard interfaces specified in the IMS framework

IMS enabler APIs for the standard enablers for services specified in the IMS framework

Application support:

IMS service enabler based applications, such as an IM client, presence client etc.

IMS core enabler based applications, where applications are not based on standard IMS service enablers

Applications that are hybrids consisting of customized combinations of IMS services enablers and IMS core enablers

The harmonization work in the IMS specifications is currently a work-in-progress with multiple standards development organizations on an industry-wide scale, and will have impacts on the evolution of the IMS client. Ericsson, PCTEL, and others have advertised various flavours of IMS clients. Overall both vendors and providers have a significant interest in the IMS framework, and the adoption timeframes are expected to be over the next few years, since it is a significant paradigm shift from the existing service delivery models.

Vendors with IMS clients include Ericsson Mobile Platforms, Movial, Ecrio, Comneon (part of Infineon) and a bunch of others. Nokia probably has its own one in development as part of a future version of S60.

Typically, the IMS software on a phone will consist of a 'framework' platform into which are plugged a bunch applications like PTT, IM, VCC, VoIP etc. The framework has a bunch of 'plumbing' protocols like the 3GPP flavour of SIP

Unfortunately, there are no standards for how the framework-application integration works. You can't put Movial application easily on top of an Ericsson framework. Until that's fixed, there will be very few IMS handsets, because developers will not want to have to port IMS apps to a dozen different IMS frameworks.

The OMTP has released some specifications about IMS phones which should help matters. There's also still a lot of questions about how the IMS part of the phone integrates with the non-IMS bits (SMS, browser, TV, IT applications , non-IMS SIP applications etc).

Given the current membership of companies in the OHA initiative, it is anticipated that the IMS client will be supported. The IMS framework is expected to be enhanced to support both SIP, and non-SIP based applications in the future. The browser enabler is a standardized service enabler specified by OMA, which leverages the underlying IMS framework, and can be integrated with an IMS client. (For instance, NetFront has a client that supports the OMA browsing enabler as well as IMS.)

The IMS framework provides a high-level of abstraction that enables applications to be developed and integrated without being impeded by the access technology specific nuances. SIP applications, or any other applications that are implemented without the IMS framework will be subject to both implementation and integration complexities, particularly in the mobile space, where the complexities of the RF link impact the implementation, integration, and the user-experience.

Note: the IMS framework has several aspects to it in terms of hooks into the various underlying access technologies, as well as a common layer of abstraction and information hiding, which is invaluable for widespread third-party application development, as well for a reduction of integration complexities. The bearer-level aspects are being addressed with respect to the various prominent access technologies such as LTE, UMB, WiMAX and Packet Cable.

According to Dean Bubley, entire Internet & IT community is negative towards IMS - Google, Microsoft, Yahoo, Skype et al.

IMS = walled-garden SIP, or perhaps more amusingly an "Internet Monetisation System".


The problem is that IMS views everything as a billable 'service' - it doesn't seem to accept that certain applications are based on the customer owning or operating their own software. In the real world, customers want certain capabilities delivered as ongoing sbillable ervices (opex) and certain things bought, owned & used outright (capex)


The current setup of the Internet is that centrally-controlled QoS and charging is anathema. IMS harks back to the legacy days of bundling access & service. That's fine for certain things, but totally inappropriate for the Internet, as that control adds latency & friction to development & innovation. I've heard IMS vendors talk about developers and "2 men & a dog in a garage", when what they actually meant was "2 men, a dog & a 30-person legal department".


As a simple example - could you imagine that anything as mindbogglingly useful as PDF would have evolved had the Internet been based on IMS principles? Download the client for free & then use it in perpetuity as a browser plug-in? No, we would all have been charged for a usage-based 'document viewing service', and it would never have got the traction.


The one thing that could change the situation is if one of the vendors - perhaps Cisco or Avaya - invented a private IMS architecture, that enterprises or large Internet firms could own. It would be deeply amusing if Merrill Lynch or GlaxoSmithKline deployed their own IMS's, and started charging interconnect fees to the telcos.

IMS Updates

Ericsson and Vodafone launched an IMS network in Czech republic this week. Under an agreement signed earlier this year, Ericsson was responsible for delivery and systems integration of its advanced IMS solution, along with project management, network design and implementation. With Ericsson's IMS solution, Vodafone Czech Republic can offer a wide range of next-generation IP telephony and multimedia services towards both fixed and mobile users. It said IMS is an important step towards fixed-mobile convergence. The international-standards-based technology is highly scalable, takes care of connection control, and ensures service quality as well as network and service security.

Aricent, a full-service, full-spectrum communications Software Company, announced this week that it has joined the IMS Forum, the industry's only forum dedicated to the acceleration of IP Multimedia Subsystem (IMS) application and service interoperability. Aricent has a dedicated IMS practice, with more than 800 person years of experience, offering an extensive portfolio of IMS software services and products. The services range from initial strategy and design, through software implementation to system integration and testing for the entire IMS architecture. These services accelerate time-to-revenue for Aricent clients and reduce their risks when deploying IMS-based solutions. With a comprehensive portfolio of IMS software services and products Aricent enables communications equipment manufacturers, device manufacturers and service providers to significantly reduce their time–to-market and mitigate the risks associated with IMS migration and roll-out.

Meanwhile, The IMS Forum, the industry's only Forum delivering IMS services interoperability verification and certification, announced recently that they have signed an MOU with the International Multimedia Telecommunications Consortium (IMTC), an international alliance of companies working together to improve the customer experience and accelerate market adoption of content delivery and unified communications solutions through interoperability of products and services based on open standards. The IMS Forum focuses on interoperability at the IMS Applications and Services Layer across mobile, fixed and cable broadband networks. The IMTC IMS Activity Group focuses on issues surrounding IMS Client interoperability, development and providing feedback to standards organizations.

Under the terms of the agreement, the IMS Forum and the IMTC will establish both a technical liaison between their Technical Working Groups and a marketing liaison. Through these liaisons the two groups will exchange technical information on IMS specifications, testing and interoperability, share interoperability testing best practices, collaborate on technical documents, and organize and participate in future joint testing events. The marketing liaison between the Marketing Working Groups will allow the organizations to share the results of their joint activities with the industry as well as promote this technology's adoption.

3GPP Release 8 = 3GPP IMS + ETSI TISPAN

Interesting development that happened last month at the 3GPP plenary meeting in Busan, Korea earlier this month, an agreement was reached on how to proceed with Common IMS to meet the needs of fixed, mobile, broadband and wireless users.

In cooperation with the European Telecommunications Standards Institute, the 3rd Generation Partnership Project (3GPP) has re-chartered a services group tasked with common ETSI-3GPP development of IP Multimedia Subsystem (IMS) Version 8.

Both standards bodies hailed the early June agreement, reached during a meeting in Busan, Korea, as an effective way to keep 3GPP IMS and ETSI Telecoms & Internet converged Services & Protocols for Advanced Networks (TISPAN) work.

Both IMS and TISPAN comprise next-generation network standards efforts designed to forge a higher signaling and control plane infrastructure layer to support delivery of content and applications to subscribers across any fixed or mobile network or device.

“ETSI TISPAN has taken the first steps in migrating fixed IMS requirements to 3GPP in a co-operation that will prevent fragmentation of IMS standards,” Dr. Walter Weigel, ETSI Director-General, said. “A Common IMS, developed in one place, is a big step forward and will bring enormous economies of scale and reductions in capital and operational costs.”

Common IMS developments will form part of 3GPP Release 8, which is expected to be functionally frozen by end 2007.

“Over the next few months we must stabilize the Release 8 requirements and absorb the incoming Common IMS work,” Stephen Hayes, Ericsson Inc., 3GPP TSG-SA Chair Stephen Hayes of Ericsson Inc., said. “3GPP has a history of successfully meeting challenges and I have no doubt we will meet these challenges as well.”

Voice call continuity (VCC)

Voice call continuity requires maintaining a voice call when a mobile terminal moves from one cell to another for second generation Global System for Mobile Communications (GSM) digital cellular communications systems. Operational for many years, this technique enables a conversation to continue when the Circuit-Switched (CS) call reroutes to use a new basestation as the mobile moves from one coverage area to another. The parties will perceive no break whatsoever.

Today, the scenario is rather more complicated, with calls being handed over not only from 2G to 2G cells and from 3G to 3G cells, but also between 2G GSM and 3G Universal Mobile Telecommunications System (UMTS) cells. This is relatively easy from an administrative point of view, given that generally the same cellular network is involved throughout.

Earlier work carried out within the 3rd Generation Partnership Project (3GPP) envisaged telephony using packet-switched connections – Voice over Internet Protocol (VoIP) – using either the 3GPP-defined IP Multimedia Subsystem (IMS) on the 3G Universal Terrestrial Access Network (UTRAN), or Wireless Local Area Network (WLAN) radio access technology based on IEEE 802.11, and other standards. This was covered by the WLAN interworking work items.

However, until now, handover between CS and IMS (packet-switched) calls was not addressed. 3GPP is now investigating the problem of handing over a voice (or potentially video or other multimedia conversational service) call between the cellular network and a WLAN, possibly operated by a completely different service provider. Again, for conversational service, the hand-over has to be seamless, with no break in service perceived by either party to the call. Until recently, such handover had only been considered for services that are not real-time, such as file-transfer, where short breaks during the handover process are acceptable and probably go unnoticed by the user.

The approach taken by 3GPP is to have the WLAN operator use the information registered by the home operator for the mobile terminal subscriber in this sequence:

1. Validate the eligibility of the handover to happen at all
2. Manage charging for the call that is effectively transferred from one network operator to another

It is generally, though not necessarily, the case that WLAN hotspots are also well covered by cellular service. Thus, such handover may take place when cellular coverage is reduced to an unacceptable level, yet an adequate WLAN hotspot service is available. The handover is more likely to occur when spare bandwidth exists on the WLAN but where excess demand for cellular channels exists.

The goal is to maintain the conversational service call, thus optimizing the service to the users, which in turn will maximize the revenue accruing to the operator(s). 3GPP embarked on the technical activity required to enable this service by approving a work item on Voice Call Continuity (VCC) in the June 2005 meeting of its Technical Specification Group System Aspects and Architecture (TSG SA). In order to be accepted onto the 3GPP work plan, any work item needs to have the support of at least four supporting member companies, and no sustained opposition. The VCC work item has no fewer than 16 supporters, and its progress
can be tracked on the 3GPP website, www.3gpp.org. It is intended that this work be achieved in the Release 7 time frame.



3GPP TR 23.806: Voice Call Continuity between CS and IMS Study (Release 7)
3GPP TS 23.206: Voice Call Continuity (VCC) between Circuit Switched (CS) and IP Multimedia Subsystem (IMS); Stage 2 (Release 7)
3GPP TS 24.206: Voice Call Continuity between the Circuit-Switched (CS) domain and the IP Multimedia Core Network (CN) (IMS) subsystem; Stage 3 (Release 7)
3GPP TS 24.216: Communication Continuity Management Object (MO) (Release 7)

http://www.compactpci-systems.com/columns/spec_corner/pdfs/2006,04.pdf
http://www.huawei.com/publications/viewRelated.do?id=1146&cid=1802
http://news.tmcnet.com/news/it/2006/06/02/1667856.htm
http://www.tmcnet.com/usubmit/-an-introduction-voice-call-continuity-vcc-/2007/05/02/2577864.htm
http://www.tmcnet.com/wifirevolution/articles/5861-voice-call-continuity-solution-dual-mode-wi-ficdma.htm

IMS strategies: Synopsis from IMS 2.0 world forum

From Ajit's Open Gardens Blog:

IMS 2.0 world forum is a must attend event .. I learnt a lot from it. Here is a brief synopsis of where I see IMS is heading to ..

Seek your thoughts and feedback especially you can identify other Operators with an interesting strategy and / or if you attended this event

As I could gather, there are six broad strategies:
a) Voice call continuity(VCC) / fixed to mobile convergence
b) Blended voice : voice tied contextually to messaging or rich media
c) SIP without IMS (Naked SIP)
d) Strategies from device manufacturers(especially Nokia and Motorola)
e) Real time IMS applications (multiplayer games and other such applications that need near real time blended media interaction within a session)
f) Abstraction of the core network

Most of the focus is around (a) Voice call continuity(VCC) / fixed to mobile convergence

This is a pity – but also understandable Operators are most familiar with voice
In its broadest sense, voice call continuity pertains to roaming within cellular and non cellular networks(such as roaming between cellular and wifi networks). A specific instance of this is Fixed to mobile convergence for instance BT fusion

My personal view is:

a) I don’t quite know if I would be interested in FMC as a customer ..
b) I think its being sold on cost – which is not a good idea
c) I think it fulfils an industry goal(fixed and mobile networks trying to get new subscribers from each other’s networks in mature markets)
d) In general, voice is becoming cheap .. so I am not sure that a pure voice play is a good idea

Blended voice(b) and real time applications(e) are interesting but need device support. Devices supporting IMS fully are conspicuous by their absence!

In contrast, devices supporting SIP(c) - but not IMS are very much here and so are applications – for instance movial

Abstracting the network layer through software APIs(f) – is the most interesting – but I felt very few Operators had the vision to embrace this strategy at the moment. The two big exceptions being TIM and Telia sonera - who are doing some very interesting work.

To recap, by abstracting the network layer, I mean : In an IP world, as the Mobile Internet mirrors the Internet, the Operator should focus on the core of the network and leave the edge of the network to third parties. Specifically, this means – identify the elements that can be performed ONLY in the core and then abstract them through APIs. This approach gets us away from the dichotomy of the ‘pipe’ vs. ‘no pipe’. It also means that the Operator retains control.

Finally, Operators in emerging markets like Globe telecom from Philippines were also impressive i.e. they understood the space, the issues specific to their market and how they could leverage IMS in their markets. Harvey G Libarnes, Head of innovation and incubations program , Globe Telecom, gave a very thorogh presentation

Finally, there are some interesting plays : such as Mobilkom with A1 over IP and France Telecom with IPTV strategy

To conclude:
a) At Operator level, IMS is still largely about voice and a defensive approach(such as FMC)
b) Lack of devices is the key question mark
c) Device manufacturers on the other hand have significant leverage(more on that soon)
d) Some operators are going to be very innovative – TIM and Teliasonera from amongst the attendees

Will WiMAX compete with 3G+

Various reports and discussions have started trying to compare WiMAX and HSPA/LTE and also justifying why WiMAX is better or vice versa. so will WiMAX compete with 3G+? To answer this problem lets go back to the beginning of 3G.

NTT DoComo launched the worlds first 3G system which it called as FOMA. Infact before FOMA it already had i-Mode available which was a revolutionary technology of its time. So instead of being so great and revolutionary, why was it not adopted by everyone. The answer is that it was a closed technology and not an open standard.

WiMAX is comparatively an open standard. Its Specifications are not available freely as is 3G. This gives 3G a definite advantage over WiMAX. Also 3G+ (which includes HSPA, HSPA+, LTE, MIMO, etc) has evolved from 3G which has in turn evolved from GSM. There is an inbuilt facility to move between 3G/GSM and perform Handovers, etc. This would be missing in WiMAX.

You may argue that once IMS is there, these problems wont be big as IMS would allow these handovers to take place. IMS is access agnostic. The problem is that it will take time for IMS to be adopted and for it to be completely functional. When this happens, by that time LTE would already be available. LTE uses the same Radio Technology as WiMAX and since it has evolved ffrom 3G/GSM, it would definitely be preferrred over WiMAX.

There was an article in Financial Express last week comparing WiMAX and 3G. Some important points from that:

But from what we do know, 3G/HSPA has several clear advantages vis-à-vis mobile WiMAX in terms of backward compatibility, standardisation, use of licensed spectrum and availability of infrastructure and terminals giving it an edge over WiMAX in terms of large scale economies leading to better affordability, availability, scalability and overall ruggedness of the 3G/HSPA standard. Further, the pace of adoption of HSPA has been remarkable. HSPA is already commercially available in Africa, America, Asia, Australia, the European Union and the Middle East. There is thus already a large ecosystem of global suppliers of components, subsystems, equipment and network design and implementation services in place for 3G/HSPA.

WiMAX on the other hand faces a number of challenges. Mobile WiMAX standards are still under evaluation. The capex for deploying WiMAX is upto 5-10 times higher than HSDPA because the size of mobile WiMax cells is upto 16 times smaller than the cells in an HSPA system, which would necessitate a larger number of base stations to cover the same geography.

Further, the prices of mobile WiMAX handsets as and when available, will be significantly higher than the cellular terminals, which are being developed in much higher volumes and offered at increasingly lower costs. Also WiMax has fragmented frequency bands. In Europe and the United States, WiMAX operates in 3.5GHz and 5.8GHz while in Asia Pacific it operates in 2.3, 2.5, 3.33 and 5.8GHz. This makes global or even pan-regional roaming rather difficult. Users visiting different countries will have to either hope that the visited country uses the same band or have their devices equipped with multiple modes to enable connectivity to other WiMAX based broadband networks. WiMAX systems also have a lower capacity for voice vis-à-vis 3G/HSPA networks, which will limit the potential market size that WiMAX can cater to.

Arthur D. Little and Altran Telecoms & Media have also produced a report for GSM Association comparing HSPA and Mobile WiMax for Mobile Broadband Wireless Access (MBWA). According to them:

HSPA is likely to account for the majority of investment in global mobile broadband networks over the next five years, finds a new study by Arthur D. Little. By comparison mobile WiMax will be a niche technology within the overall
global mobile broadband wireless access market, likely to account for at most 15% of this network equipment market and perhaps 10% of mobile broadband wireless subscribers by 2011-2012.

HSDPA (including HSUPA and HSPA+) is taking the lead as it is a natural migration path for a large number of GSM and UMTS operators already operating commercial networks in 3G spectrum. This will give rise to significant economies
of scale on handsets and user devices and a large ecosystem of global suppliers of components, subsystems, equipment and network design and implementation services. Hence this is the least risky and best understood route to offering broadband mobile services which can offer speeds comparable to first generation fixed DSL services.

According to a report in Broadband Wireless Exchange Magazine:

The results of Arthur D. Little's modeling work shows that WiMax systems are expected to achieve significantly greater theoretical peak data transfer rates when deployed than today's commercial HSPA networks deliver now, such as theoretical speeds of e.g. 16.8 Mbps in urban areas vs 2-3 Mbps for HSPA. However, the coverage a WiMax base station can achieve, is substantially lower than HSPA, hence HSPA operators will be able to deploy a smaller number of base stations and sites to cover the same geography. Indications are that radio access network capex for current WiMax technology can significantly exceed HSDPA capex.

Another consequence of this characteristic of these two technologies is that an HSPA operator will be able to match its growing investment more clearly to the development of demand than mobile WiMax operators who will have to install more cell sites at the beginning to ensure coverage.

Arthur D. Little acknowledges that in the longer term, well into the second decade of this century, mobile broadband wireless systems will be characterized by technologies such as OFDMA and MIMO. Development of these technologies is being pursued by the 3G/HSPA ecosystem within the framework of 3G LTE as well as by WiMax. The long term future relative roles of 3G LTE and mobile WiMax, both of which face major development hurdles before they achieve the full promise of new, so-called 4G systems, is uncertain and will be influenced by continuing expected shifts in the priorities and competitive alignments of major players in the wireless industry which has undergone a number of consolidations in recent months.

In contrast to many other reports on HSPA, mobile WiMax and other broadband wireless technologies, the Arthur D. Little study highlights and assesses all the factors - strategic, competitive, commercial, regulatory and political as well as technological that influence operators' choices of wireless network technology.

Evidence for the potential complementary nature of HSPA and WiMax can be seen in the increased interest in multi-mode user devices and roaming capabilities across the technologies. This development, which reflects the widespread anticipation of the central role of OFDMA and other technologies involved in WiMax and 3G LTE in all eventual future broadband wireless networks, is a welcome change from the provocative and misleading headlines that have appeared over the past two years which imply that mobile WiMax threatens the viability of today's HSPA and related technologies

With Intel promising WiMAX chips on all its laptops in future, only time will tell how far WiMAX will and if this comparison holds true.

MBMS Enhancements in Release 7

MBMS will be undergoing enhancements in Release 7 and this work item is seperate from E-MBMS or Enhanced MBMS which is part of 3GPP Long Term Evolution (LTE).

MBMS is being enhanced in Release 7 and IMS will be able to use MBMS transport. The advantage of this approach is:

• MBMS reception is possible over IP accesses (e.g. I-WLAN)


• Higher MBMS bit rate services possible (e.g. HDTV)


• Support for adaptation of MBMS to the QoS resources provided by the access network(s)


• MBMS services will be available regardless of access technologies and other services will be able to usse MBMS transport

This MBMS Enhancement is still under development and the following is being investigated:

• Radio Interface Physical Layer: Introduction of new transmission schemes and advanced multi-antenna technologies


• Layer 2 and 3: Signalling optimisations


• UTRAN Architecture: Identify the most optimum architecture and functional splits between RAN network nodes
  

3GPP website lists some of the aims and objectives of these MBMS enhancements but theey do not look correct. They are copied from the LTE requirements documents. I will be revisiting this topic when more information is available