#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.

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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

View more presentations from Zahid Ghadialy

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.