#LTEWS: Highlights and Pictures of Signalling day from 8th LTE World Summit

I got a chance to attend the 'Handling the Surge in Signalling Traffic Focus day' at the LTE World Summit. In fact I got this opportunity through Diametriq, who were the sponsors of this event and were kind enough to provide me a free pass :) As a result, they get a little plug below.

We got off to a flying start with an Introduction to the need of Signaling followed by a brilliant presentation by Martin Pineiro from Telecom Personal, Argentina.

This was the only presentation that looked at the Access Network Signalling. All other presentations focussed on Diameter signaling. Telecom Personal have 4 carriers, 1 is used for 3G and other 3 for GSM.

Above is their revenue share for different services. The data services really took off for them when they offered a flat rate if 1 peso per day for unlimited data.

Their average dongle data consumption is 2GB/month and average smartphone is 200MB/month.

They do have a simple definition of Smartphone, which is a device that produces 10+ packet connections per day. The device that is most popular in their network is Motorola and Apple devices produce highest data load but their comparison of devices from different manufacturers showed they all produced similar signalling traffic. 

One final point highlighted was that OS & Apps are not part of test and certification so we should get better understanding of that to help avoid signalling overload in future.

Ron de Lange from Tekelec was up next:

Interesting to hear that they are 40 year old company with 300+ customers in 100+ countries.

There is a shift coming in the usage plans with multi access roaming. Some sessions will go over WiFi and some over the mobile network. Plans with OTT allowance are already here and will be more common. There may be opportunity for end users to earn allowance as part of loyalty scheme. The main thing for operator to think is how to get a revenue share from advertisement.

Diameter 2.0 is coming. The signalling storms, if not handled properly can cause disruption (congestion) internationally, if the interconnect is not handled properly.

Next up was Ben Volkow, F5 Traffix:

Today we use Diameter 1.0, tomorrow it would be Diameter 2.0. Diamater 2.0 us "nervous system" approach.

Diamater is much less predictable than SS7 but this could be because of Immaturity of Diameter.

Real networks like the one above is out in the field. An example of n/w is one with 140 point to point connections.

DRA (Diameter Routing Agent) is a new topology introduced by 3GPP and DEA (Diameter Edge Agent) was introduced by GSMA.

The network does not want to spend million of dollars in one go so they start by deploying individual components first and then depending on the use cases this scales up as they add more components.

Next up was the Panel Discussion:

Key points:

• Diameter is first protocol that has dedicated vendors offering monetisation of protocol as well
• Early operators would have deployed Diameter 1.0 so they can evolve by putting DRA for one use case and so on.
• When operators want to monetise using diameter, the signalling problems may become worse
• Adding VoLTE may increase Diameter Signalling by 3 times
• What is meant by monetisation of Diamater is that in SS7, the focus was on reliability, etc. but in Diameter, the operators can leverage PCRF and as a result monetisation. A new use case can also be a OTT proxy that can leverage advertisement revenue. 
• The forecast for Diameter is couple of 100 million for this year and growing. There are many components including Router, Roaming, Charging, Security, Interconnect capability, Aggregating relationships with small carriers and OTT service providers, etc.

Next up was Marjan Mursec of Telecom Slovenia: 

Some interesting facts from them is that they have a public WLAN n/w, GSM with EDGE as fallback and have rolled out HD voice. Their Data usage surpasses voice and Voice and SMS is still growing as can be seen below.

Above shows the data usage increase after they rolled out all you can eat package. They were then forced to introduce fair usage policy.

Their upgrade paths include RAN, Core, Backhaul.

They think they have a big signalling challenge over S1-MME interface. One wrong configured user is sending 4 requests/second. 12,500 users can be enough to reach congestion (ZG: Maybe they should look at PDP Context Parking). Over the S1-U interface, Narrowband users can send 50 packets/sec. 40,000 users at 13.6kbps can saturate the network and the routers will be overloaded.

Next up was Ajay Joseph from iBasis:

Interesting to see that GRX is a service in IPX above.

I think the main point of above is that Diameter by itself is not enough and a mechanism like IPX is required for roaming scenario.

For LTE a new service called LTE Signalling exchange (LSX) can be created within IPX. iBasis has just launched Sandbox for testing Roaming, Charging, Interoperability, etc.

Will LSX bring the roaming costs down? Its operators call but it does provide a foundation and in the next 2-3 years, data roaming costs should come down dramatically.

It should be noted that GRX is an IP network without QoS. Its a service within IPX. Security is also a service within IPX and GSMA based compliance should be there for proper and secure interoperability.

Voice over IPX is not of much interest, especially because there is no return of investment and HD voice cant be send over IP.

Next up was Douglas Ranalli from NetNumber:

His slides are self explanatory

One question during Q&A was, why not put this functionality in the cloud and avoid complexity of having another physical box in the system. The answer was that CDRB is implemented to be compliant with cloud deployment but operators have not yet taken this step. The customers are deploying physical boxes but shared infrastructure would be much more efficient.

Next up was Doug Alston from Sprint:

Next up was Anjan Ghosal from Diametriq:

Everyone is talking about LTE-LTE roaming but there is a need for LTE-3G and LTE-2G so some translation may be required between Diameter and SS7.

Diametriq provides a single platform for signalling between any service (2G/3G/4G) and possibility to enhance.

Next up was another Panel Discussion:

One observation is made is that as compared to the ITM Optimisation event, where the operators were more worried about the OTT players eroding revenues, the focus here was that how Diameter can help monetise the OTT services,

Next up was Edward Gubbins from Current Analysis:

The Final presentation was from Julius Mueller from Fraunhofer FOKUS:

As usual, Dimitris Mavrakis was up to the mark and chaired the whole day very well.

To end an enjoyable day even better, iBasis invited the attendees for drinks on the Hilton Terrace, which is next to CCIB and complemented the drinks with some delicious Tapas as can be seen below :)

E&OE. In case if have misheard, misquoted, etc. please feel free to correct me via comments in this post.

For all the action from LTE World Summit for the next 2 days, please follow twitter #LTEWS.

Please let me know by using the voting buttons below if you found it useful or not.

Enhanced Uplink SC-FDMA: PUSCH+PUCCH Simultaneous Transmission

RoHC & RoHCv2

Its been a while since I blogged about Robust Header Compression (RoHC). You can see the old posts here and here. Here is an example message showing the header compression information.

RoHCv2 is also available as specified in RFC 5225.

Fourth proposal for the nano-SIM Card (4FF)

I blogged about the nano-SIM card earlier and the 3 proposals that are causing the deadlock. Here is a new fourth proposal that has been submitted by RIM that is a compromise between the Apple and Nokia designs (see pic here). Proposal as seen below:

According to The Register:


At issue is the shape and size of the standard next-generation SIM: Apple and a band of network operators want a tray-requiring shape and contacts that would permit a convertor for backwards compatibility with chunkier old SIMs. Nokia, Motorola and RIM have pushed for a new contact pattern and a notched SIM for clunk-click, and tray-less, insertion.


The new proposal, apparently put forward by RIM and Motorola, is a compromise but it hasn't secured backing from either of the most-belligerent parties - yet. Copies of the design, as well as Moto's presentation in March that compared the competing interfaces, have been seen by the chaps at The Verge.


What all parties agree on is that a smaller SIM is needed: the first SIMs were the same size as credit cards (conforming to ISO7816), while the second form factor (2FF) is the SIM with which most of us are familiar (conforming to GSM 11.11). Next was the microSIM (3FF), popularised by Apple's adoption in the iPhone; the 3FF just trims off the excess plastic while maintaining the contact pattern.


The undecided 4FF standard (dubbed the nanoSIM) will be thinner as well as smaller, and almost certainly feature a different contact pattern to make that practical, although how different is part of the ongoing debate.


The Apple-backed 4FF proposal was for a contact-compatible SIM with smooth sides necessitating an insertion tray, while Nokia wanted the contacts shifted to the far end and a notch along the side for easy push-to-lock fitting. The new RIM-Moto proposal, if genuine, places the contacts in compatible locations while maintaining the Nokia notch, appeasing both parties or perhaps annoying them both equally.


There have been claims that Nokia is just trying to protect its patent income, fanned by Apple's offer to waive its own IP fees if its proposal were adopted. That's something of a red herring as Apple's hasn't much IP in this area and Nokia's patents cover much more than the physical shape of the SIM so its revenue is pretty much assured.


Not that Nokia has helped itself by threatening to deny patent licences if its own proposal isn't adopted, claiming that Apple's divergence from rules laid down by telecoms standards body ETSI relives Nokia of its FRAND commitment to licence its technology on a fair and reasonable basis.

A slidepack by RIM on the 4FF UICC is embedded below and available to download from slideshare:

4FF: The next generation UICC

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Backhauling the Telefonica O2 London LTE Trial

Interesting Video and Presentation about backhaul in the London Trial of LTE deployment by O2.


Presentation:

Efficient mobile backhaul

View more PowerPoint from Cambridge Broadband Networks Limited

We have an event in October in Cambridge Wireless that will look at the backhaul and deployments a bit more in detail. Details here.

SPS and TTI Bundling Example

I have blogged about Semi-Persistent Scheduling (SPS) and Transmit Time Interval (TTI) Bundling feature before. They are both very important for VoIP and VoLTE to reduce the signalling overhead.

It should be noted that as per RRC Specs, SPS and TTI Bundling is mutually exclusive. The following from RRC specs:

TTI bundling can be enabled for FDD and for TDD only for configurations 0, 1 and 6. For TDD, E-UTRAN does not simultaneously enable TTI bundling and semi-persistent scheduling in this release of specification. Furthermore, E-UTRAN does not simultaneously configure TTI bundling and SCells with configured uplink.

The Voice Evolution: VoLTE, VoHSPA+, WCDMA+ and Quality Evolution

Circuit switched-fallback-the-first-phase-of-voice-evolution-for-mobile-lte-devices from Prashant Sengar

-x-o-x-o-x- Edited 20/05/2012 -x-o-x-o-x-

I found a related presentation and webinar video on this topic so adding that below:

WCDMA+ Makes Voice More Efficient to Support More Data from Qualcomm Wireless Evolution

Traffic Flow Template (TFT), GBR and QoS

Location Services in LTE Networks

Recently made a combined architecture of LTE with LCS and MBMS and posted it here. This document from MSF below looks at the LoCation Services (LCS) in detail.

MSF Whitepaper on Location Services in LTE Networks

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A Twitter discussion on 'Data Tsunami' myth

Participants:


@disruptivedean - Dean Bubley
@StevenJCrowley - Steve Crowley
@WhatTheBit - Stefan Constantine
@labboudles - Leila Abboud
@twehmeier - Thomas Wehmeier
@jamncl4 - Jonathan Morgan
@wifidave - Dave Wright

@disruptivedean: Data tsunami myth washing further out to sea: Telefonica mobile data grew 35% YoY to Q1, vs. data rev growth of 28%. http://www.telefonica.com/en/shareholders_investors/html/financyreg/resultados2012.shtml


@disruptivedean: Increasingly convinced that some cellular data growth numbers & forecasts are over-inflated - mainly to sway regulators on spectrum policy

@StevenJCrowley: Wonder how much of Telefonica lower data growth is from Spain's unusually bad economy versus normal "S curve"

@twehmeier: Did you see that shockingly unbalanced story on data traffic in FT? Pure spin. Telefonica is v representative of Euro ops. The other factor is vendors perpetuating the myth to sell their products and services

@WhatTheBit: you should do some research into operator spectrum holdings versus actual utilization, I'm sure the results would B shocking

@twehmeier: The other factor is vendors perpetuating the myth to sell their products and services

@disruptivedean: Don't think Spanish economy that much an issue. Growth been flattening in UK & Germany for a while - http://disruptivewireless.blogspot.co.uk/2011/11/smoking-gun-i-think-o2-uk-has-falling.html


@disruptivedean: The contrast in attitude between TF corporate vs. TF Digital is striking sometimes.

@labboudles: that's interesting, is it typical of others ops numbers, ie data makes them money so stop whining abt capex/google?

@disruptivedean: It's certainly true for VF in Europe - they have faster data rev growth than traffic growth. Caps/tiers fixed the problem


@disruptivedean: Basic pricing tiers/caps + user-controlled WiFi have "fixed" the problem. Has undermined need for more complex solutions & tech

@twehmeier: Indeed. amazes me how little emphasis placed on imprtnce of pricing. Next prob will be working out how to bring traffic back

@disruptivedean: Yes, especially with LTE - in some places/networks we're heading for overcapacity. Not quite as bad as fibre in 2001, but scary

@twehmeier: And that will likely lead to more naive pricing models that only serve to accelerate self-commoditisation of value of data!


@twehmeier: Telenor firsy reported faster data revenue growth versus traffic back in 2010. And that's in some of the world's most advanced smartphone and MBB markets...

@labboudles: thought so since that was case in France, but admit had not looked at all ops trends

@disruptivedean: Also beware that some operators (eg AT&T) have started adding in WiFi hotspot traffic to bump up the numbers

@twehmeier: Shameless lobbying....

@labboudles: where is there overcapacity?! Places where LTE has been built and already used?

@twehmeier: imagine a market where Wi-Fi is ubiquitous and all operators deploy LTE on top of pre-existing HSPA/HSPA+. And remember average utilisation of European 3G networks is typically only in the 35-40% range and pretty steady

@labboudles: that's a ways off in real world though


@labboudles: ok that I just don't understand, then why is my user experience of mobile Internet so crap n London, Paris ?

@disruptivedean: Depends how you calculate it. Bear in mind many MNOs don't "light up" all spectrum initially, but add extra capacity


@disruptivedean: Plenty of other bottlenecks - most notable is poor coverage, could be backhaul, stuff in core network, even DNS etc


@disruptivedean: Congestion often caused by too much signalling (setting up/tearing down IP conxns), not sheer data "tonnage"

@jamncl4: Actually I think we are also seeing the impact of the shift from laptops to tablets and smartphones


@jamncl4: People can't afford multiple data plans so they shift from laptop to Smartphones which inherently use less data

@wifidave: How did you arrive at 35%/28%? I found 15.4% YoY in "mobile data revenue", and couldn't find traffic figures.

@jamncl4: Same with tablets which also pull usage away from laptop except most tablets are wifi only


@jamncl4: WiFi is in enough places that I can't justify two data plans so I stick to wifi tablet and data pla smartphone

@disruptivedean: It's on page 6 of the results presentation, showing rapid convergence of traffic & revenue growth

@jamncl4: The smartphone will take a few years to catch up to laptops in terms of data requirements thus "slowdown" growth

@disruptivedean: Bear in mind rising % of people don't have "plans" but use PAYG for data. But yes, dongle traffic falling, phone rising

@jamncl4: But Smartphone require higher signaling than laptops due to apps & power saving techniques;massive signal growth

@disruptivedean: Tablet/laptop substitution (or not) largely irrelevant as both are generally WiFi-only & will most likely stay that way

@jamncl4: Multi device plans could be interesting moving forward and there impact on this


@jamncl4: I disagree. Majority of traffic has come from laptops in past so more wifi & tablets reduces the traffic

@wifidave: @disruptivedean OK, I see. The 27% is a subset of the 15.4%.

@jamncl4: I think the real issue is that people don't want to pay for 2 plans & the 1 plan in general is Smartphone for now. Multidevice PAYG plans will be interesting on their impact.

@wifidave: Ponder this > Assuming TF #s are cell data, they represent a mobile data Traffic/Rev YoY growth ratio of 1.29:1 . The same ratio for #ChinaMobile in Q4'11 was 1.28:1 . For #ChinaMobile, cell data grew at 56.1% traffic and 43.5% revenues.


@wifidave: ATT says that "wireless data traffic" doubled in 2011 from 2010. (http://www.attinnovationspace.com/innovation/story/a7781181). but elsewhere report that their Wi-Fi traffic increased 550% in Q4'11. (http://www.vision2mobile.com/news/2012/01/wif.aspx). all while wireless data revenues only grew 19.4% YoY in Q4'11 (http://www.att.com/gen/press-room?pid=22304&cdvn=news&newsarticleid=33762)


@wifidave: The real growth (337% and 550% for CM and ATT) is in Wi-Fi as Dean said. Not adding much to rev yet.

@disruptivedean: Absolutely agree more WiFi = less "big device mobile data traffic". Unconvinced it matters if big device = laptop/tablet


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Updated LTE Architecture with LCS and MBMS entities

Here is an attempt to update the LTE Architecture with MBMS and Location Services (LCS) entities included

You can also refer to the following old posts:

• Simplifying LTE/SAE Interfaces
• 3GPP Official 'MBMS support in E-UTRAN' - Mar 2011
• MBMS in LTE Release-9

Mobile Banking and Payments in Emerging Markets

Post PC Era: Mobile Banking and Payments in Emerging Markets

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MIM: Machine Identity Module - M2M SIM

WiFi: Standards, Spectrum and Deployment

Yesterday, IEEE published its fourth revision to 802.11. The updates include faster throughput, improved cellular hand-offs, and better communication between vehicles in addition to other improvements.The following from IEEE website:

The new IEEE 802.11-2012 revision¹ has been expanded significantly by supporting devices and networks that are faster, more secure, while offering improved Quality of Service and, improved cellular network hand-off. IEEE 802.11 standards, often referred to as “Wi-Fi®,” already underpin wireless networking applications around the world, such as wireless access to the Internet from offices, homes, airports, hotels, restaurants, trains and aircraft around the world. The standard’s relevance continues to expand with the emergence of new applications, such as the smart grid, which augments the facility for electricity generation, distribution, delivery and consumption with a two-way, end-to-end network for communications and control.

IEEE 802.11 defines one MAC and several PHY specifications for wireless connectivity for fixed, portable and mobile stations. IEEE 802.11-2012 is the fourth revision of the standard to be released since its initial publication in 1997. In addition to incorporating various technical updates and enhancements, IEEE 802.11-2012 consolidates 10 amendments to the base standard that were approved since IEEE 802.11’s last full revision, in 2007. IEEE 802.11n™, for example, defined MAC and PHY modifications to enable much higher throughputs, with a maximum of 600Mb/s; other amendments that have been incorporated into IEEE 802.11-2012 addressed direct-link setup, “fast roam,” radio resource measurement, operation in the 3650-3700MHz band, vehicular environments, mesh networking, security, broadcast/multicast and unicast data delivery, interworking with external networks and network management.

“The new IEEE 802.11 release is the product of an evolutionary process that has played out over five years and drawn on the expertise and efforts of hundreds of participants worldwide. More than 300 voters from a sweeping cross-section of global industry contributed to the new standard, which has roughly doubled in size since its last published revision,” said Bruce Kraemer, chair of the IEEE 802.11 working group. “Every day, about two million products that contain IEEE 802.11-based technology for wireless communications are shipped around the world. Continuous enhancement of the standard has helped drive technical innovation and global market growth. And work on the next generation of IEEE 802.11 already has commenced with a variety of project goals including extensions that will increase the data rate by a factor of 10, improve audio/video delivery, increase range and decrease power consumption.”

¹ IEEE 802.11™-2012 “Standard for Information technology--Telecommunications and information exchange between systems Local and metropolitan area networks--Specific requirements Part 11: Wireless LAN Medium Access Control (MAC) and Physical Layer (PHY) Specifications”

The following is from a presentation by Agilent in LTE World Summit last year. It summarises the 802.11 standards, the Spectrum available and deployment use cases.

LTE deployment and optimisation challenges

Presented in the 3G, HSPA, LTE Optimisation conference, April 2012 by Ljupco Jorguseski. The ICIC presentation referred to in this presentation is available in an earlier post here.

LTE deployment and optimisation challenges

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Telefonica UK London Small Cells (Wi-Fi, 3G, 4G)

From a presentation by Robert Joyce, Chief Radio Engineer, Telefonica UK in the 3G, HSPA, LTE Optimisation conference.

LTE 'Antenna Ports' and their Physical mapping

People who work with LTE Physical layer and maybe higher layers would be aware of this term called 'Antenna Ports'. I have always wondered how these antenna ports are mapped to physical antennas.

The following is from R&S whitepaper:

The 3GPP TS 36.211 LTE standard defines antenna ports for the downlink. An antenna port is generally used as a generic term for signal transmission under identical channel conditions. For each LTE operating mode in the downlink direction for which an independent channel is assumed (e.g. SISO vs. MIMO), a separate logical antenna port is defined. LTE symbols that are transmitted via identical antenna ports are subject to the same channel conditions. In order to determine the characteristic channel for an antenna port, a UE must carry out a separate channel estimation for each antenna port. Separate reference signals (pilot signals) that are suitable for estimating the respective channel are defined in the LTE standard for each antenna port. 

Here is my table that I have adapted from the whitepaper and expanded. 

The way in which these logical antenna ports are assigned to the physical transmit antennas of a base station is up to the base station, and can vary between base stations of the same type (because of different operating conditions) and also between base stations from different manufacturers. The base station does not explicitly notify the UE of the mapping that has been carried out, rather the UE must take this into account automatically during demodulation (FIG 2).

If there is another way to show this physical mappings, please feel free to let me know.

The R&S Whitepaper is available here if interested.

'License-exempt' bands in the UK

10 Times Beyond LTE-A (5G maybe?)

Recently when I added a presentation by NSN on whats coming after IMT-Advanced, it was very well received and has already had over 8000 views. There seems to be definitely an appetite for the future networks. Here is another such presentation.

10 Times Beyond LTE-A

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There is also a video of the presentation if you have the patience to sit, watch and learn.

3 Stages for Seamless Mobility between 3G and WLAN

Evolution of Machine Type Communications (MTC)

RAN Release 11 Priorities

Signalling Load per device and OS

From the presentation by Martin Prosek, Telefonica, Czech Republic in 3G Optimization Conference 2012, Prague.

Signalling can cause many issues:

In the mobile device, Frequent PDP-context establishment is known to drain the battery. Battery life can be improved by supporting fast dormancy in network.

In the network, Signalling flood can create situations reminding DoS attacks. Increased signalling in RAN can cause impacts in core network:

• Radius/Diameter interface overload of AAA servers
• DHCP IP address pools exhaustion

New Spectrum for LTE-Advanced Carrier Aggregation

LTE and IPv6

A discussion on Linkedin prompted me to add some relevant documents relating to LTE and IPv6. Interesting presentation below by Cisco:

Designing LTE with IPv6

View more presentations from Zahid Ghadialy. Available to download from slideshare here.

There are some other interesting presentations on slideshare you may want to look at:

• Embracing IPv6 - part of the Joint GSMA/NGMN Conference Stream “Technology Evolution”
• Advances in IPv6 Mobile Access - John Loughney,Nokia
• IEEE Globecom 2010: Mobile Communication and IPv6 - John Loughney,Nokia
• T-Mobile USA IPv6 Deployment

3GPP System Building on Releases

ICIC: Status, performance impact and automation

Inter-Cell Interference Coordination (ICIC)

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