The shape-shifting future of the mobile phone

SS7, IMS, SIP and Diamater

Going through my pile of 1 million things to read before I die, I came across this presentation by Tekelec with regards to why Diamater and SIP would be used instead of SS7 in LTE and IMS. The slide in the picture above shows the comparison of SS7 and Diamater.

More and more operators are asking for replacement of SS7 with the Diamater interface. The main reason being that it has been adopted by 3GPP and when we move to an all IP network as in case of LTE it makes sense to have Diamater instead of SS7. There is a good description of Diameter on Wikipedia (cant guarantee the accuracy though) here.

You can read more about SIP at the Tekelec blog here.

There is also an interesting Radvision presentation on Slideshare that I have embedded below:

Cell search and cell selection in UMTS LTE

Cell search and cell selection in UMTS LTE

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A normal day in 2014

Against the Limited "Unlimited" data plans

Once upon a time the Mobile Operators had loads of bandwidth and not enough data users. So they decided to lure the poor users into buying the 'unlimited' data plans. They were sure that the devices are quite rubbish and no one can use enough data. Just for the precaution some clever operators added a small print where unlimited meant 1 or 2GB. The operators thought that the users will never reach this amount.

Then came the iPhone and changed the whole world. People actually started using the data on their devices. The operators started panicking. Android just compunded this problem. So the operators now have started advocating against these unlimited plans.



The CEO of Vodafone , Vittorio Colao , has told attendees at this year's Nokia World 2010 event that he welcomes the end of "unlimited" Mobile Broadband data plans. Colao also warned consumers that "data pricing has to adjust", thus signalling a greater focus on tiered pricing models.

He added: "The principle here must be that, a bit like motorways or hotels, every class of service needs to have its own price and customers must be able to pay for the level of service [they want]. Pricing should be adjusted to reflect the usage and load. We are approaching the end of the free era."

The cowboy salesmen are still fooling the average Joe when it comes to unlimited plans. People sue the operators but dont succeed.

We are begging to see the return of those bad old days when WiFi was the only option in conferences, etc and they were really expensive. Now instead of WiFi we have got our dongles that may not work well anyway inside the conferences or hotels due to the structure or location but when they do, you again have to think about the costs.

In Korea, KT Telecom had to introduce unlimited plans because the other rival introduced one. This is probably because they still have spare bandwith available. Once that gets used up then they will either be running for caps or advocating against the unlimited plans.

I have been against the unlimited plans from the beginning but I advocate that the operators become a bit wise in the way they charge us, the end users.

If I have 4 devices I dont want limited data on all devices because I dont want to keep track of which devices use how much data or have an allowance. Maybe what I need is a data bundle that I can use across devices and maybe share with my family members. Wallmart has recently come up with something similar in US. Wallmart is a MVNO using T-Mobile network. Though their data plans are expensive compared to T-Mobiles plans just because they allow data sharing and rollover, people may go for them.

Rollovers are available on Pay as you go plans but not on Pay monthly which makes the pay monthly (generally on contract) people seem stupid. Operators should encourage this, maybe keep a maximum that can be rolled over.

Finally, there is this net neutrality and QoS discussions are going on. Eventually some kind of QoS or destination based speeds, etc will come but for the end user they will go where they will get what they want. The operators should remember this.

Femtocell Interference Management in real life

Couple of years back we blogged about the Femtocell Inteference in Macro network. Since then things have moved on a long way. There are commercial rollouts happening with Vodafone leading the way. Yesterday, I was reading Prof. Simon Saunders article on Femtocell and the following struck me.

A major technical challenge that femtocell designers initially faced was the need to manage potential interference. It takes up to two years to install conventional base stations, during which time radio engineers meticulously plan a station’s position and radio characteristics to avoid interference. However, such an approach is not viable in the case of femtocells, deployed potentially in their millions at random. Automating a process conducted by radio engineers was no mean feat and simply would not have been possible a few years ago.

Fortunately, the fact that the walls of buildings keep 3G signals out and keep the femtocell’s signals in provides strong inherent interference mitigation for indoor femtocells. Extensive studies have shown that proper implementation of a few key techniques to reduce interference can take advantage of this attenuation in an intelligent manner. Such techniques include frequent monitoring of the cell’s surrounding radio environment combined with adaptive power control. Indoor users gain faster data rates, as do outdoor users who now operate on less congested cells, while it costs less for operators to deliver higher overall network capacity. Large-scale, real-world deployments are demonstrating that these techniques work in practice and even allow new approaches, such as operating 3G networks in the same spectrum as 2G networks.

AT&T has deployed femtocells on the same frequencies as both the hopping channels for GSM macrocells and with UMTS macrocells. They have tested thousands of femtocells, and found that the mitigation techniques implemented successfully minimise and avoid interference. The more femtocells are deployed, the more uplink interference is reduced.

It is very interesting to see that the interference is not causing any problems in real life.


Back in Feb, Femto Forum released a new report on "Interference Management in UMTS Femtocells". A similar report was released in Dec. 08. Then in March they released a similar report for OFDMA (covering both LTE and WiMAX) femtocells. They are interesting reading for those who are interested in this area.


European Union is having a similar program called FREEDOM (Femtocell-based network enhancement by interference management and coordination of information for seamless connectivity ). FREEDOM focuses on:

• Advanced interference-aware cooperative PHY techniques,
• Improvement of the control plane procedures for seamless connectivity, and
• System-level evaluation and hardware demonstrator of the proposed femto-based network architecture.

More info on their website (http://www.ict-freedom.eu/). You can see their scenario document that shows different interference scenarios and also compares different approaches including those of Femto Forum, 3GPP and WiMAX.

Selected IP Traffic Offload (SIPTO)

The industry is developing a new standard called Selected IP Traffic Offload (SIPTO). SIPTO allows internet traffic to flow from the femtocell directly to the internet, bypassing the operator’s core network, as shown in Figure 8 below.

More information on LIPA and SIPTO can be obtained from:

1. 3GPP TR 23.829: Local IP Access and Selected IP Traffic Offload (http://www.3gpp1.eu/ftp/Specs/archive/23_series/23.829/)

2. Femtocells – Natural Solution for Offload (http://www.3gamericas.org/documents/016+Femtocells+Natural+Solution+for+Offload%5B1%5D.pdf)

Local IP Access (LIPA) for Femtocells

I blogged about data offload earlier, for Femtocells. This traffic offload can be done via a feature called Local IP Access (LIPA). If you have LIPA support in your Home NodeB (HNB) or Home eNodeB (HeNB) then once you have camped on your Femtocell then you can access your local network as well as the network's IP network.

This would mean that you can directly print from your mobile to the local printer or access other PC's on your LAN. Note that I am also referring to access via Dongle as Mobile access though in practice I dont see much point of people just using dongles when they are in their Home Zone. Every laptop/notebook/netbook is now Wifi enabled so this situation doesnt benefit much for the dongle access.

I am sure there are quite a few unresolved issues with regards to the Security of the data, the IP address allocation, QoS, etc.

Continuous computing have a white paper on LIPA available that can be obtained by registering here. Anyway, enough information is available even without getting the PDF.

There is also a small presentation here that gives a bit of idea on LIPA.

As usual any comments, insights and references welcome.

Japan M-Commerce Morgan Stanley report

Interesting reading.Japan M-Commerce Morgan Stanley report

View more presentations from Zahid Ghadialy.

Cell Phone and Driving Funny and Seriously...

Cell Phone and Driving Funny and Seriously

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