Monday, May 21, 2012

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.

Sunday, May 20, 2012

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:


Saturday, May 19, 2012

Backhauling the Telefonica O2 London LTE Trial

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


Presentation:
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.

Monday, May 14, 2012

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.

Saturday, May 12, 2012

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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Friday, May 11, 2012