Voice over LTE - GSMA Presentation

Voice over LTE

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Interesting article on Voice options in LTE

Interesting article summarising the Voice issues in LTE from Total Telecom Magazine.

Voice Over LTE Network

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The complete issue of the magazine is available here.

Running live networks on Renewable Energy sources

We have been hearing for years that Solar energy could be used to run remote BTS/Node B so i was glad to see that they are deployed in practise and are working well. It was very interesting to see hear Pradeep de Almeida, Group Chief Technology Officer, Dialog Telekom Plc, Sri Lanka in the LTE World Summit.

The picture above lists the features from an ideal renewable energy powered BTS or Node B (or eNodeB for that matter). The picture below shows one of the real life deployments in Sri Lanka.

It was very interesting to hear that the power generated using the Solar and Wind approach is generally in surplus and this extra energy could be sold to the power companies or can be used to provide an outlet point where the people can come and charge their phones.

The return of investment (ROI) for these kind of deployments could be as low as 2 years and can be as high as 4 years. The time for ROI will be reduced for countries where diesel (used for generators) is expensive and will be increased when diesel is cheap. That is why we may not find environmently friendly approaches in Middle East for quite some time because of cheap oil.

You can read more about the Dialog Telekom green energy initiative here and here.

Your number’s up

In what sounds like the plot of a horror movie, a Bulgarian cellphone company has reportedly suspended the number 0888-888-888 after every single person who was assigned to it in the last 10 years died.

A spokesperson for Bulgarian firm MobilTel refused to comment, telling the Telegraphthat they don’t discuss individual numbers. But the newspaper tracked down the phone number’s eerie history and discovered that each owner had met an untimely end.

The first owner was the former MobilTel CEO, Vladimir Grashnov. In 2001, the 48-year-old died of cancer, although some speculated that he was radioactively poisoned by a business rival.

The number was then passed on to Konstantin Dimitrov, a Bulgarian mafia boss and owner of a $775-million drug smuggling empire. He was shot by a lone assassin in 2003 while eating out with a model in the Netherlands. He was 31.

The third and final owner was Konstantin Dishliev, a real-estate-agent-by-day and a drug-lord-by-night, who secretly ran a massive cocaine trafficking ring. In 2005, after police intercepted $200-million of the white stuff on its way in from Columbia, Mr. Dishliev was assassinated outside a restaurant in Bulgaria’s capital city.

After being temporarily suspended during the investigation into Mr. Dishliev’s death, the number is said to have been de-activated for good. Now anyone who calls is greeted with a recorded message saying the phone is “outside network coverage.”

So are the deaths merely coincidence or proof of a cell phone curse?

Whatever the case, MobilTel could stand to profit off the number by selling it to someone in China, where the number eight is considered lucky. In 2003, a Chinese airline paid 2.33-million yuan (US$280,723) for the phone number 8888-8888.

Quick preview of 3GPP Release-11 Features and Study items

Release 11 Features

Advanced IP Interconnection of Services

The objective is to specify the technical requirements for carrier grade inter-operator IP Interconnection of Services for the support of Multimedia services provided by IMS and for legacy voice PTSN/PLMN services transported over IP infrastructure (e.g. VoIP). These technical requirements should cover the new interconnect models developed by GSMA (i.e. the IPX interconnect model) and take into account interconnect models between national operators (including transit functionality) and peering based business trunking. Any new requirements identified should not overlap with requirements already defined by other bodies (e.g. GSMA, ETSI TISPAN). Specifically the work will cover:

• Service level aspects for direct IP inter-connection between Operators, service level aspects for national transit IP interconnect and service level aspects for next generation corporate network IP interconnect (peer-to-peer business trunking).

• Service layer aspects for interconnection of voice services (e.g. toll-free, premium rate and emergency calls).

• Service level aspects for IP Interconnection (service control and user plane aspects) between Operators and 3rd party Application Providers.

To ensure that requirements are identified for the Stage 2 & 3 work to identify relevant existing specifications, initiate enhancements and the development of the new specifications as necessary.


Release 11 Studies

Study on IMS based Peer-to-Peer Content Distribution Services

The objectives are to study IMS based content distribution services with the following aspects:

- Identifying the user cases to describe how users, operators and service providers will benefit by using/deploying IMS based content distribution services. such as with the improvement of Peer-to-Peer technology. The following shall be considered:

- Mobile access only (e.g. UTRAN, E-UTRAN, I-WLAN);

- Fixed access only (e.g. xDSL, LAN);- Fixed and mobile convergence scenarios;

- Identifying service aspects where IMS network improvements are needed to cater for content distributed services for above accesses;

- Evaluating possible impacts and improvements on network when IMS based content distribution services are deployed;

- Identifying QoS, mobility, charging and security related requirements in the case of content distribution services on IMS;

- Identifying potential copyright issues;

Study on Non Voice Emergency Services

The Non Voice Emergency Services could support the following examples of non-verbal communications to an emergency services network:

1. Text messages from citizen to emergency services

2. Session based and session-less instant messaging type sessions with emergency services

3. Multi-media (e.g., pictures, video clips) transfer to emergency services either during or after other communications with emergency services.

4. Real-time video session with emergency services

In addition to support the general public, this capability would facilitate emergency communications to emergency services by individuals with special needs (e.g., hearing impaired citizens).

The objectives of this study include the following questions for Non Voice Emergency Services with media other than or in addition to voice:

1. What are the requirements for Non Voice Emergency Services?

2. What are the security, reliability, and priority handling requirements for Non Voice Emergency Services?

3. How is the appropriate recipient emergency services system (e.g., PSAP) determined?

4. Are there any implications due to roaming?

5. Are there any implications to hand-over between access networks

6. Are there any implications due to the subscriber crossing a PSAP boundary during Non Voice Emergency Services communications (e.g., subsequent text messages should go to the same PSAP)?

7. Do multiple communication streams (e.g., voice, text, video emergency services) need to be associated together?

8. What types of “call-back” capabilities are required?9. Investigate the load impact of Non Voice Emergency Services in the case of a large scale emergency event or malicious use.

Non Voice Emergency Services will be applicable to GPRS (GERAN, UTRAN) and to EPS (GERAN, UTRAN, E-UTRAN and non-3GPP).

Study on UICC/USIM enhancements

The intent of this study item is to identify use cases and requirements enabling Mobile Network Operators to distribute new services based on the USIM, to improve the customer experience and ease the portability and customisation of operator-owned and customer-owned settings from one device to another (such as APN and other 3G Notebook settings, graphical user interface, MNO brand, Connection Manager settings,…), and help in reducing operation costs and radio resources usage.

Objectives of this study item are:

-To identify use cases and requirements for new USIM

-based services taking into account the GSMA Smart SIM deliverables;

- To identify use cases and requirements for the USIM used inside terminals with specialised functionalities (e.g. radio modems, 3G Notebook terminals) taking into account the GSMA 3GNBK deliverables;

- To identify use cases and requirements to drive the evolution from the traditional USAT to a multimedia USIM toolkit support, with a particular aim to the Smart Card Web Server;

Study on Alternatives to E.164 for Machine-Type Communications

M2M demand is forecast to grow from 50M connections to over 200M by 2013. A large number of these services are today deployed over circuit-switched GSM architectures and require E.164 MSISDNs although such services do not require "dialable" numbers, and generally do not communicate with each other by human interaction.

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:

- Effectively identify addressing method to be used for end point devices

- Effectively route messaging between those devices

- Support multiple methods for delivering messages, as defined by 22.368

- Support land-based and wireless connectivity

- Make use of IP-based network architectures

- Addressing/identifiers must support mobility and roaming- support on high speed packet

-switched networks when available and on circuit-switched networks

- Consider if there are security issues associated with any alternatives

ZTE shows off its green credentials

ZTE has long been focussing on green(er) network and recycling. They launched their new generation 'green base stations back in 2006. They have also been recently cited for their energy saving technology. They also have a solar powered phone which is unfortunately not available in UK. Their Omni-RAN network can help reduce the OPEX by two thirds. Their focus has not only been on Mobile phones and networks but on the fixed lines as well.

So it was not at all surprising to hear Xiaodong Zhu, CTO of ZTE European marketing in the LTE World Summit talking about the end to end green networks. Green technology is not only helpful to for the 'green credentials' but it can also help reduce Opex which can help recover any additional investments (if any).

More manufacturers will hopefully follow the lead.

LTE Femtocell Enhancements for Release-9

LTE Release 9 provides further functionality to support more efficiently HeNBs operation and to provide a better user experience. The key functionality added the Radio Access Network for HeNBs in Release 9 are:

• A novel Hybrid Cell concept

• Management of out-of-date CSG info

• Inbound Mobility (including proximity reports)

• Access Control

• Operation, Administration and Maintenance for HeNB

• Operator controlled CSG list

• RF Requirements for TDD and FDD HeNBs

Nomor Research have recently released a paper that covers all these issues and much more. Titled "LTE Home Node Bs and its enhancements in Release 9", its available to download here.

Using Femtocells abroad Illegaly

Back in 2008, I blogged about Femtocells and stealing of Spectrum. Since the rollout of Vodafone Suresignal, I am seeing people discuss it more and more about using the Femtocells abroad. I should say as I have in the past that this would be illegal and I wouldn't encourage anyone to do it but as couple of people have mentioned to me in private that they have managed to do it I would like to hear if someone else has managed this feat.

Since you need to have the IP address belonging to the country your femtocell is registered to, this means that you need to use a VPN along with the Femto to make sure that your IP packets look like they are coming from the country. At the same time your mobile should only be working with your Femto in a sheilded space (basement kind of location preferably to avoid any GPS chip picking up your location).

Another way you can give your game away to the operator is to handout from the mobile to a foreign network. It will definitely send some bells ringing.

ng-connect LTE car from ALU

Back in the LTE World Summit 2010 there was this ng-connect LTE car demo. I wasn't able to get a demo as there didnt seem to be anyone willing to be filmed for the blog. The first I heard about this ng.connect program was last year when I blogged about the case for early LTE in USA.

The ng connect program ecosystem brings together lots of companies that are collaborating from research to sales and marketing. If you click in the picture above you will be able to see the enlarged image and at the bottom you can see the names of these companies. The car is ofcourse Toyota but I wasnt able to see that in the list of companies.

The following Youtube clip gives an introduction to the connected car

The following is from the Demo from France. In January 2010, Alcatel-Lucent launched for the first time in Europe the ng Connect LTE Connected Car in its Velizy, France facility, showcasing the capabilities that Long Term Evolution (LTE), the next generation of mobile networks, will bring to automakers, service providers, application developers and end users. Also demo'd in Velizy was the live LTE drive tour in a van, testing mobile services on a campus-wide network, demonstrating a smooth transition between 3G/HSPA and LTE networks.

The final video is slightly longer clip which shows the thought process behind the connected car.

If you havent had enough already then I would also recommend this post.

UMTS/HSPA State Transition Problems to be solved with LTE

The way UMTS/HSPA is designed is that the Mobile (UE) is always in IDLE state. If there is some data that needs to be transferred then the UE moves to CELL_DCH. If the amount of data is very less then the UE could move to CELL_FACH state. The UE can also move to CELL_PCH and URA PCH if required but may not necessarily do so if the operator has not configured those states.

The problem in UMTS/HSPA is that these state transitions take quite some time (in mobile terms) and can slow down the browsing experience. Martin has blogged about the state transition problems because of the keep alive messages used by the Apps. These small data transfers dont let the UE go in the IDLE state. If they do then whole raft of signalling has to occur again for the UE to go to CELL_FACH or CELL_DCH. In another post Martin also pointed out the sluggishness caused by the UE in CELL_FACH state.


Mike Thelander of the Signals Research Group presented similar story in the recently concluded LTE World Summit. It can be seen from the figure above that moving from IDLE to CELL_DCH is 1-3secs whereas FACH to DCH is 500ms.

In case if some Apps are running in the background, they can be using these keep alive messages or background messages which may be very useful on the PC but for the Mobiles, these could cause unnecessary state transitions which means lots of signalling overhead.

The Apps creators have realised this problem and are working with the Phone manufacturers to optimise their messaging. For example in case of some Apps on mobiles the keep alive message has been changed from 20 seconds to 5 mins.

3GPP also realised this problem quite a while back and for this reason in Release-7 two new features were added in HSPA+. One was Continuous Packet Connectivity (CPC) and the other was Enhanced CELL_FACH. In Release-8 for HSPA+, these features were added in UL direction as well. The sole aim of these features were to reduce the time it would take to transit to CELL_DCH. Since CPC increases the cell capacity as well, more users can now be put in CELL_FACH instead of being sent to IDLE.

An interesting thing in case of LTE is that the RRC states have been simplified to just two states as shown here. The states are IDLE and CONNECTED. The intention for LTE is that all the users can be left in the CONNECTED state and so unnecessary signalling and time spent on transitioning can be reduced.

The preliminary results from the trials (as can also be seen from here) that were discussed in the LTE World Summit clearly show that LTE leads to a capacity increase by 4 times (in the same BW) and also allow very low latency. I am sure that enough tests with real life applications like Skype, Fring and Yahoo IM have not been done but I am hopeful of the positive outcome.