Monday 18 April 2011
Multimedia Telephony (MMTel) in 3GPP Rel-7
Tuesday 1 March 2011
Rich Communication Suite (RCS)
Thursday 20 January 2011
eMPS: Enhanced Multimedia Priority Service in Release-10 and beyond
- Mechanisms to allocate resources for signaling and media with priority based on subscribed priority or based on priority indicated by service signaling.
- For a terminating IMS session over LTE, a mechanism for the network to detect priority of the session and treat it with priority.
- A mechanism to properly handle the priority terminating voice call and enable the target UE to establish the AS and NAS connection to fall-back to the GERAN/UTRAN/1xRTT.
Wednesday 22 December 2010
Voice over LTE – a step towards future telephony (Ericsson Whitepaper)
Saturday 4 December 2010
Role of ENUM in NGN Interconnect
Friday 3 December 2010
Presentation: IMS for 3G Voice Services and Migration Strategies
Thursday 2 December 2010
The 3GPP release 8 IMS Implementation, Deployment & Testing workshop
Monday 8 November 2010
Single Radio Voice Call Continuity (SR‐VCC)
Thursday 4 November 2010
Emergency Calls in LTE/SAE Release-9
Wednesday 22 September 2010
SS7, IMS, SIP and Diamater
Going through my pile of 1 million things to read before I die, I came across this presentation by Tekelec with regards to why Diamater and SIP would be used instead of SS7 in LTE and IMS. The slide in the picture above shows the comparison of SS7 and Diamater.
More and more operators are asking for replacement of SS7 with the Diamater interface. The main reason being that it has been adopted by 3GPP and when we move to an all IP network as in case of LTE it makes sense to have Diamater instead of SS7. There is a good description of Diameter on Wikipedia (cant guarantee the accuracy though) here.
You can read more about SIP at the Tekelec blog here.
There is also an interesting Radvision presentation on Slideshare that I have embedded below:
Thursday 2 September 2010
4G Mobile Network & Applications
Thursday 3 June 2010
Quick preview of 3GPP Release-11 Features and Study items
Advanced IP Interconnection of Services
Release 11 Studies
Study on IMS based Peer-to-Peer Content Distribution Services
Objectives of this study item are:
Without technical alternative to using public numbering resources as addresses, and considering the current forecasts and pending applications for numbers made to numbering plan administration agencies, there is a significant risk that some national numbering/dialling plans will run out of numbers in the near future, which would impact not only these M2M services but also the GSM/UMTS service providers in general.
The Objective is to determine an alternative to identify individual devices and route messages between those devices. Requirements for this alternative include:
Friday 6 November 2009
'One Voice Initiative': IMS Based approach adopted
AT&T*, Orange, Telefonica, TeliaSonera, Verizon, Vodafone, Alcatel-Lucent, Ericsson, Nokia Siemens Networks, Nokia, Samsung Electronics Co. Ltd., and Sony Ericsson have defined the preferred way to ensure the smooth introduction and delivery of voice and SMS services on Long Term Evolution (LTE) networks worldwide.
The above telecommunications industry leaders have jointly developed a technical profile for LTE voice and SMS services, also known as the One Voice initiative. The profile defines an optimal set of existing 3GPP-specified functionalities that all industry stakeholders, including network vendors, service providers and handset manufacturers, can use to offer compatible LTE voice solutions.
Open collaborative discussions have concluded that the IP Multimedia Subsystem (IMS) based solution, as defined by 3GPP, is the most applicable approach to meeting the consumers’ expectations for service quality, reliability and availability when moving from existing circuit switched telephony services to IP-based LTE services. This approach will also open the path to service convergence, as IMS is able to simultaneously serve broadband wireline and LTE wireless networks.
By following the jointly defined technical profile, the industry can help guarantee international roaming and interoperability for LTE voice and SMS services, ensuring subscribers continuity of these vital services – all while offering service providers a smooth and well-defined path to LTE.
The objective of the initiative is to ensure the widest possible ecosystem for LTE and to avoid fragmentation of technical solutions. LTE will, with this initiative, not only serve as a broadband access for increasing data traffic, but also for continuing voice and SMS services. Network operators will be able to more quickly develop their customized LTE ecosystem in collaboration with both network equipment vendors and device manufacturers. In addition, the reassurance of global interoperability in an LTE voice landscape and the ability to offer both broadband access and telephony services over LTE will create strong foundations for future business.
The profile for the initial solution has been finalized and is available through the companies associated with this press release. The objective is to hand over the profile and continuing work to existing industry forums.
To view the technical profile, please visit http://news.vzw.com/OneVoiceProfile.pdf.
From Rethink Wireless:
One of the trickiest issues for early LTE deployers is uncertainty over how voice and SMS services - still the key cash cows for most operators - can be supported. Eventually, all these services will be carried over IP, using the IMS (IP Multimedia Subsystem) standard, but only a few carriers, like Verizon Wireless, are looking to deploy all-IP from day one. However, there is pressure to accelerate the process and reduce the cost and risk of LTE/IMS for carriers, and this is the objective of the new One Voice initiative.
Some operators believe they will initially deploy LTE as a data-only network, but most want to support voice and, even more importantly, SMS (which underpins many cellco processes and customer communications). Faced with the risk that large players might delay their plans until they have a strong route to voice, One Voice has defined a profile based on existing 3GPP standards for IMS-enabled voice.
The work has initially emerged from Nokia Siemens, which was previously trying to get wide industry support for its own interim voice over LTE solution, VoLTE (which only worked with its own softswitches). The company's convergent core marketing manager, Sandro Tavares, said One Voice should ease fears over how voice will be deployed by resolving roaming and interworking issues at an early stage. It is not creating a new standard, but aims to ensure compatibility between networks and devices by creating a common profile, which defines an optimal set of existing 3GPP functionalities for use by vendors and operators. "There is no new standard," added Tavares. "It's just using what is there already."
NSN is already producing LTE equipment that complies with the new profile, and so has a headstart in offering an important feature to early triallists - which could boost its so-far low profile in LTE tests, dominated by Ericsson and Huawei. However, the vendor will now hand its work to the 3GPP and GSM Association so that other companies can work on and adopt the profile. So far, it has signed support from most of the key operators that tend to wield influence over cellular standards, apart from DoCoMo and China Mobile - AT&T, Orange, Telefonica, TeliaSonera, Verizon Wireless and Vodafone are there, plus a strong line-up of vendors. These are Alcatel-Lucent and Ericsson on the infrastructure side and Nokia, Samsung and Sony Ericsson for devices. The group needs to get the Chinese vendors on board to complete the set, as well as Motorola.
The supporters of the initiative say this is their "preferred path" for voice over LTE, though for carriers that do not want to move to IMS at an early stage, there are other options available - namely open web-based voice; the stopgap solution of Circuit Switch Fallback (also enshrined in 3GPP standards), where the handset is forced off the LTE network onto 2G or 3G for voice calls; and variations on the theme of using circuit switch over packet techniques. There are two main approaches to this - MSC Voice, which is tied to a switch, with NSN's VoLTE the most prominent example; and VoLGA, which is architecture independent, and uses the UMA/GAN (Unlicensed Mobile Access/Generic Access Network) protocol. This Kineto originated technology was originally adopted for Wi-Fi/3G fixed-mobile convergence and as such did find its way into the 3GPP. VoLGA does not require modifications in the LTE RAN or core, or the MSC, but uses a separate gateway controller.
Some of the One Voice supporters are already involved in VoLGA (though its major carrier T-Mobile has not yet joined the new group). Steve Shaw, who heads up corporate marketing for Kineto and VoLGA, believes that IMS is the way that, ultimately, voice will be handled, but it has a long way to go before it is usable, and so there will still be a role for several years for approaches like VoLGA.
T-Mobile will I assume soon have to follow suit and fall in line otherwise they may have limited devices that are available and there will also be inter-operability issues.
Last week I attended a presentation by IET Berkshire on Voice Services over LTE, presented by Iain Sharp from Nortel. Even though this announcement came yesterday, Iain did say that IMS is the way forward for Voice over LTE. If interested you can see the presentation here.
Tuesday 14 April 2009
IMS Deployment and Future Strategy
Sunday 23 November 2008
Solving the LTE voice dilemma
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.
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.
Tuesday 23 September 2008
NEC and Ubiquisys to help deploy first IMS based Femtocell Solution
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.
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.
Saturday 13 September 2008
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
Monday 1 September 2008
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.
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.
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 - 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
Tuesday 12 August 2008
IMS: Reality check
- 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:
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.
Saturday 2 August 2008
LTE, IMS and Voice calls!
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.
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.