Two VoLTE Deployment Case Studies

Back in 2011, I was right in predicting that we will not see VoLTE as early as everyone had predicted. Looking through my twitter archive, I would say I was about right.

As I said earlier, CSFB for now and VoLTE around 2014 - RT @mitchellkp: LTE won't find voice anytime soon http://t.co/mn0EwAw

— Zahid Ghadialy (@zahidtg) September 7, 2011

Soon = before 2015. Ideally, if its working then never, until forced - RT @Gabeuk: I suspect VoLTE adoption will pick-up briskly in 2013.

— Zahid Ghadialy (@zahidtg) July 13, 2011

The big issue with VoLTE has always been the complexity. In a post last year I provided a quote from China Mobile group vice-president Mr.Liu Aili, "VoLTE network deployment is the one of the most difficult project ever, the implementation complexity and workload is unparalleled in history".

From a recent information published by IHS, there will only be 310 million subscribers by end of 2016 and 2020 is when 1 billion subscribers can make use of VoLTE. I think the number will probably be much higher as we will have VoLTE by stealth.

Below are couple of case studies, one from SK Telecom, presented by Chloe(Go-Eun) Lee and other from Henry Wong, CTO Mobile Engineering, Hong Kong Telecom (HKT). Hope you find them informative and useful.

Feasibility Study on New Services and Markets Technology Enablers for 5G

3GPP SA1 (see tutorial about 3GPP if you dont know) recently released four new Technical Reports outlining the New Services and Markets Technology Enablers (SMARTER) for next generation mobile telecommunications.

3GPP TR 22.891 has already identified over 70 different which are into different groups as can be seen in the picture above. These groups are massive Internet of Things (MTC), Critical Communications, enhanced Mobile Broadband, Network Operation and Enhancement of Vehicle-to-Everything (eV2X).

The first 4 items have their own technical reports (see below) but work on the last item has only recently started and does not yet have a TR to show to the outside world. It is foreseen that when there are results from the eV2X study these will be taken on board in the Smarter work. (thanks to Toon Norp for this info)

The four Technical Reports (TR) are:

• TR 22.861, FS_SMARTER – massive Internet of Things (MTC): Massive Internet of Things focuses on use cases with massive number of devices (e.g., sensors and wearables). This group of use cases is particularly relevant to the new vertical services, such as smart home and city, smart utilities, e-Health, and smart wearables.
• TR 22.862, FS_SMARTER – Critical Communications: The main areas where improvements are needed for Critical Communications are latency, reliability, and availability to enable, for example, industrial control applications and tactile Internet. These requirements can be met with an improved radio interface, optimized architecture, and dedicated core and radio resources.
• TR 22.863, FS_SMARTER – enhanced Mobile Broadband: Enhanced Mobile Broadband includes a number of different use case families related to higher data rates, higher density, deployment and coverage, higher user mobility, devices with highly variable user data rates, fixed mobile convergence, and small-cell deployments.
• TR 22.864, FS_SMARTER – Network Operation: The use case group Network Operation addresses the functional system requirements, including aspects such as: flexible functions and capabilities, new value creation, migration and interworking, optimizations and enhancements, and security.

Embedded below is 3GPP TR 22.891 which has a lot of interesting use cases and makes a useful reading.

EE's vision of Ultra-Reliable Emergency Network

Many of my readers would be aware that UK is probably the first country to have decided to move its emergency services network from an existing TETRA network to a commercial LTE network operated by EE.

While some people have hailed this as a very bold move in the right direction, there is no shortage of critics. Around 300,000 emergency services users will share the same infrastructure used by over 30 million general users.

The following is from an article in Wireless Magazine:

Steve Whatson, deputy director Delivery, Emergency Services Mobile Communications Programme (ESMCP) – the organisation within the UK Home Office procuring ESN – assured delegates that ESN will match the existing dedicated Airwave emergency services communication network in terms of coverage for roads, outdoor hand portable devices and marine coverage. Air to ground (A2G) will extend its reach from 6,000ft to 12,000ft.

Whatson also pointed out that coverage is not one single piece, but will comprise a number of different elements, which all need to mesh into one seamless network run by the ESN Lot 3 Mobile Services (main 4G network) provider – EE.

This includes: EE’s main commercial 4G network; Extended Area Services (hard-to-reach areas of the UK where new passive sites are to be built under a separate contract and then equipped with EE base stations); air-to-ground; London Underground; Crossrail; marine coverage (to 12 nautical miles); and special coverage solutions.

EE is currently rolling out new 4G sites – it will eventually have some 19,500 sites – and is upgrading others with 800MHz spectrum, which propagates over longer distances and is better at penetrating buildings than its other 4G spectrum holdings. Crucially for ESN, it is also switching on a Voice over LTE (VoLTE) capability, starting with the UK’s main cities.
...
Mission critical networks must be always available and have levels of resilience far in excess of commercial networks. Speaking exclusively to Wireless in early May, Tom Bennett, group director Technology Services, Architecture & Devices at EE, said: ‘We already achieve a very high availability level, but what the Home Office was asking for effectively was about a 0.3% increase against our existing commercial availability levels.

‘Now for every 0.1% increase in availability there is a significant investment because you are at the extreme top end of the curve where it is harder and harder to make a noticeable difference.’

There are very specific requirements for coverage and availability of the ESN network for the UK road system. Bennett says: ‘Mobile is based on a probability of service. No more than 1% of any constabulary’s roads are allowed to be below 75% availability, and on major roads it is 96% availability. A coverage gap in this context is no more than 1km.’

The current Airwave network has approximately 4,000 sites, many with back-up generators on site with fuel for seven days of autonomous running if the main power is cut, along with a range of resilient backhaul solutions.

Bennett says that out of EE’s 18,500 sites it has about the same number of unique coverage sites (ie. no overlapping coverage) – around 4,000. ‘As part of our investment programme, those unique coverage sites will need a significant investment in the causes of unavailability – ie. resilient backhaul and back-up batteries.’

He explains that EE has undertaken a lot of analysis of what causes outages on its network, and it has combined that data with the Home Office’s data on where the natural disasters in the UK have occurred over the past 10 years.

From this, EE is able to make a reasonable assessment of which sites are likely to be out of action due to flooding or other disasters for more than three or four days. ‘For those sites – and it is less than 4,000 – you need generators too, because you may not be able to physically access the sites for some days,’ says Bennett.

For obvious reasons, the unique coverage sites are mostly in rural areas. But as Bennett points out, the majority of cases where the emergency services are involved is where people are – suburban and urban areas.

‘In these areas EE has overlapping coverage from multiple sites to meet the capacity requirements, so if a site goes down, in the majority of cases we have compensation coverage. A device can often see up to five tower sites in London, for example,’ he says.

Having adequate backhaul capacity – and resilient backhaul at that – is vital in any network. Bennett says EE is installing extra backhaul, largely microwave and fibre, but other solutions will also be used including satellite and LTE relay from base station to base station – daisy chaining. On 9 May 2016, EE announced a deal with satellite provider Avanti to provide satellite backhaul in some areas of the UK.

Additional coverage and resilience will be offered by RRVs (rapid response vehicles), which EE already has in its commercial network today, for example, to provide extra capacity in Ascot during the racing season.

‘We would use similar, although not exactly the same technology for disaster recovery and site/service recovery, but with all the backhaul solutions,’ says Bennett. ‘Let’s say we planned some maintenance or upgrade work that involved taking the base station out for a while.

‘We’d talk to the chief inspector before the work commences. If he says, there’s no chance of doing that tonight, we can put the RRV there, and provided we maintain coverage, we can carry out the work. RRVs are a very good tool for doing a lot of things.’

At the British APCO event, Mansoor Hanif, director of Radio Access Networks at EE said it was looking at the possibility of using ‘airmasts’ to provide additional coverage. Meshed small cells, network in a box and repeater solutions are becoming available for these ‘airmasts’, which will provide coverage from balloons, or UAVs – tethered drones with power cables and optical fibre connected to them.

Mansoor Hanif, Director of RAN at EE gave a presentation on this at Critical Communications World 2016 and has also given an interview. Both are embedded below.

Ultra-Reliable Networks – A Mobile Operator Perspective from 3G4G

Feel free to let me know if you believe this will work or not and why.

Three Presentations on 5G Security

Here are three presentations from the 5G Huddle in April, looking at 5G security aspects. As I have repeatedly mentioned, 5G is in process of being defined so these presentations are just presenting the view from what we know about 5G today.

History: 30 years of the mobile phone in the UK

In January 1985 the UK launched its first mobile networks. Now, thirty years on, many people and companies in the UK have been celebrating this enormous achievements and advances that have been made since then and which have seen the mobile evolve from a humble telephone into the multimedia pocket computer which has become such an essential part of modern life. It was simply not possible in 1985 to envisage a country that would be able to boast more active mobile phones than people or to have along the way clocked up several world firsts, and be now leading on the deployment of 4G and shaping the future 5G technologies.

Below is a series of talks in an event organised by University of Salford,



The following talks are part of playlist:

1. Launch of Vodafone – Nigel Linge, on behalf of Vodafone
2. Launch of Cellnet - Mike Short, O2
3. The emergence of GSM - Stephen Temple, 5GIC
4. The launch of Mercury one2one and Orange - Graham Fisher, Bathcube Telecoms
5. From voice to data - Stuart Newstead, Ellare
6. Telepoint - Professor Nigel Linge, University of Salford
7. 3G - Erol Hepsaydir, 3 UK
8. Handset evolution and usage patterns - Julian Divett, EE
9. 4G and onwards to 5G – Professor Andy Sutton, EE  and University of Salford.

For anyone interested in reading about the history of mobile phones in UK, read this book below with more facts and figures

If you have any facts to share, please feel free to add in the comments below.

AT&T's 5G Trials

There was a news recently that "AT&T 5G trials expand, break 10 Gbps throughput". The article said:

Austin, Texas, where RCR Wireless News and Industrial IoT 5G Insights is headquartered, is where AT&T worked with the Federal Communications Commission to get an experimental license to conduct 5G technology trials using spectrum in the 3.4-3.6 GHz, 3.7-4.2 GHz, 14.5-15.35 GHz and 27.5-28.5 GHz bands. The carrier said the testing would be used for “experimental equipment” in support of “potential (5G) multi-gigabyte per second applications for fixed and mobile wireless communication networks at higher transmission rates and lower latency than is currently available,” and supporting voice, video and data.
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“We’ve seen great results in our 5G lab trials, including reaching speeds above 10 gigabits per second in early tests with Ericsson,” said Tom Keathley, SVP of wireless network architecture and design at AT&T. “Nokia is joining to help us test millimeter wave, which we expect to play a key role in 5G development and deployment. The work coming out of AT&T Labs will pave the way toward future international 5G standards and allow us to deliver these fast 5G speeds and network performance across the U.S.”

While I have seen speed records being set, this will not be of much help in the final standards. Some of you may remember my earlier post where Huawei achieved over 100Gbps in their labs. See here.

A video from recent AT&T mmWave trials is below:

5G and Future Technologies from Johannesberg Summit

Johannesberg Summit is an annual forum to discuss how Wireless ICT is transforming business and society.  Interesting talks from industry leaders and leading academics are mixed with panel discussions with a broad perspective on technologies, services, business and policy models that may have an impact in the long-range evolution of society and various industries. Topics have over the years included future user behavior and requirements, novel services and applications, new business models as well as policy and regulation. These more general topics have been matched with visions on how wireless technologies and architectures can handle these needs.

The 2016 summit had 4 key topic areas:

• The transformation of the transport industry
• The transformation of the manufacturing industry (“Industry 4.0”)
• Future key technologies
• Update on 5G year

The best things is that they make all the presentations available online. Initially in the video form and later on the PDF's as well. I am embedding playlist of all video talks below but have a look at the program here.

You can also look at the 2015 program here that includes videos and PDFs of the presentations from last year.

5G & 802.11ax

Samsung is one of the 5G pioneers who has been active in this area for quite a while, working in different technology areas but also making results and details available for others to appreciate and get an idea on what 5G is all about. 

I published a post back in 2014 from their trials going on then. Since then they have been improving on these results. They recently also published the 5G vision paper which is available here and here.

Lots of interesting technical details on 5G trials by @RajGawera, @SamsungUK #5GHuddle pic.twitter.com/BLXPFV9EjY

— Zahid Ghadialy (@zahidtg) April 26, 2016

In the recent 5G Huddle, Raj Gawera from Samsung gave an excellent presentation (below) on the topic of "The future connected world". 

What we really liked is how closely 5G and 802.11ax can be considered aligned, not only in terms of requirements but also the roadmap.

Fascinating talk from @RajGawera concludes with a review of the 5G & 802.11ax roadmaps #5GHuddle pic.twitter.com/P5sbvkc0jB

— Andy Sutton (@960sutton) April 26, 2016

Anyway, here is the presentation embedded below. Let me know what you think in the comments below.

QCI Enhancements For Mission Critical Communications

Its been quite a while since I posted about QCI and end-to-end bearer QoS in EPC. In LTE Release-12 some new QCI values were added to handle mission critical communications.

This picture is taken from a new blog called Public Safety LTE. I have discussed about the Default and Dedicated bearers in an earlier post here (see comments in that post too). You will notice in the picture above that new QCI values 65, 66, 69 & 70 have been added. For mission critical group communications new default bearer 69 would be used for signalling and dedicated bearer 65 will be used for data. Mission critical data would also benefit by using QCI 70.

LTE for Public Safety that was published last year provides a good insight on this topic as follows:

The EPS provides IP connectivity between a UE and a packet data network external to the PLMN. This is referred to as PDN connectivity service. An EPS bearer uniquely identifies traffic flows that receive a common QoS treatment. It is the level of granularity for bearer level QoS control in the EPC/E-UTRAN. All traffic mapped to the same EPS bearer receives the same bearer level packet forwarding treatment. Providing different bearer level packet forwarding treatment requires separate EPS bearers.

An EPS bearer is referred to as a GBR bearer, if dedicated network resources related to a Guaranteed Bit Rate (GBR) are permanently allocated once the bearer is established or modified. Otherwise, an EPS bearer is referred to as a non-GBR bearer.

Each EPS bearer is associated with a QoS profile including the following data:
• QoS Class Identifier (QCI): A scalar pointing in the P-GW and eNodeB to node-specific parameters that control the bearer level packet forwarding treatment in this node.
• Allocation and Retention Priority (ARP): Contains information about the priority level, the pre-emption capability, and the pre-emption vulnerability. The primary purpose of the ARP is to decide whether a bearer establishment or modification request can be accepted or needs to be rejected due to resource limitations.
• GBR: The bit rate that can be expected to be provided by a GBR bearer.
• Maximum Bit Rate (MBR): Limits the bit rate that can be expected to be provided by a GBR bearer.

Following QoS parameters are applied to an aggregated set of EPS bearers and are part of user’s subscription data:
• APN Aggregate Maximum Bit Rate (APN-AMBR): Limits the aggregate bit rate that can be expected to be provided across all non-GBR bearers and across all PDN connections associated with the APN.
• UE Aggregate Maximum Bit Rate (UE-AMBR): Limits the aggregate bit rate that can be expected to be provided across all non-GBR bearers of a UE. The UE routes uplink packets to the different EPS bearers based on uplink packet filters assigned to the bearers while the P-GW routes downlink packets to the different EPS bearers based on downlink packet filters assigned to the bearers in the PDN connection.

Figure 1.5 above shows the nodes where QoS parameters are enforced in the EPS system.

Related links:

• LTE QoS and prioritization for mission critical communication
• LTE QCI and End-to-end bearer QoS in EPC
• VoLTE Bearers
• New book by Nokia experts on LTE for Public Safety a must read

4G / LTE by stealth

In the good old days when people used to have 2G phones, they were expensive but all people cared about is Voice & SMS.

The initial 3G phones were bulky/heavy with small battery life, not many apps and expensive. There was not much temptation to go and buy one of these, unless it was heavily subsidised by someone. Naturally it took a while before 3G adoption became common. In the meantime, people had to go out of their way to get a 3G phone.

With 4G, it was a different story. Once LTE was ready, the high end phones started adding 4G in their phones by default. What it meant was that if the operator enabled them to use 4G, these devices started using 4G rather than 3G. Other lower end devices soon followed suit. Nowadays, unless you are looking for a real cheap smartphone, your device will have basic LTE support, maybe not advanced featured like carrier aggregation.

The tweets below do not surprise me at all:

Another data point for Turkey #4.5G: There were 5 million new LTE subscriber additions on the first *day* of launch. (no 4G before)

— Dimitris Mavrakis (@dmavrakis) May 10, 2016

With Huawei in Istanbul for a 4.5G event. Apparently there are 40 million 4G subscribers 1 month after LTE launch (by all 3 MNOs).

— Dimitris Mavrakis (@dmavrakis) May 10, 2016

This is what I refer to as 4G or LTE by stealth.

Occasionally people show charts like these (just using this as a reference but not pin pointing anyone) to justify the 5G growth trajectory with 4G in mind. It will all depend on what 5G will mean, how the devices look like, what data models are on offer, what the device prices are like, etc.

I think its just too early to predict if there will be a 5G by stealth.