Temporary Identities in LTE/SAE - 1

An MS may be allocated three TMSIs, one for services provided through the MSC (TMSI), one for services provided through the SGSN (P-TMSI for short) and one for the services provided via the MME (M-TMSI part GUTI for short).

The purpose of the GUTI is to provide an unambiguous identification of the UE that does not reveal the UE or the user's permanent identity in the Evolved Packet System (EPS). It also allows the identification of the MME and network. It can be used by the network and the UE to establish the UE's identity during signalling between them in the EPS.

The GUTI has two main components:

• one that uniquely identifies the MME which allocated the GUTI; and
• one that uniquely identifies the UE within the MME that allocated the GUTI.

Within the MME, the mobile shall be identified by the M-TMSI.

The Globally Unique MME Identifier (GUMMEI) shall be constructed from the MCC, MNC and MME Identifier (MMEI).

The MMEI shall be constructed from an MME Group ID (MMEGI) and an MME Code (MMEC).

The GUTI shall be constructed from the GUMMEI and the M-TMSI.

For paging purposes, the mobile is paged with the S-TMSI. The S-TMSI shall be constructed from the MMEC and the M-TMSI.
S-TMSI = MMEC + M-TMSI

The operator shall need to ensure that the MMEC is unique within the MME pool area and, if overlapping pool areas are in use, unique within the area of overlapping MME pools.

The GUTI shall be used to support subscriber identity confidentiality, and, in the shortened S-TMSI form, to enable more efficient radio signalling procedures (e.g. paging and Service Request).


The format and size of the GUTI is therefore the following:
GUTI = GUMMEI + M-TMSI, where
GUMMEI = MCC + MNC + MME Identifier and
MME Identifier = MME Group ID + MME Code
MCC and MNC shall have the same field size as in earlier 3GPP systems.
M-TMSI shall be of 32 bits length.
MME Group ID shall be of 16 bits length.
MME Code shall be of 8 bits length.

During Handover to GERAN/UTRAN
RAI = MCC + MNC + LAC + RAC
E UTRAN "MCC" maps to GERAN/UTRAN "MCC"
E UTRAN "MNC" maps to GERAN/UTRAN "MNC"
E UTRAN "MME Group ID" maps to GERAN/UTRAN "LAC"
E UTRAN "MME Code" maps to GERAN/UTRAN "RAC" and is also copied into the 8 most significant bits of the NRI field within the P TMSI;

"P-TMSI" includes the mapped NRI
P TMSI shall be of 32 bits length where the two topmost bits are reserved and always set to 11.

E UTRAN "M-TMSI" maps as follows:
6 bits of the E UTRAN "M-TMSI" starting at bit 29 and down to bit 24 are mapped into bit 29 and down to bit 24 of the GERAN/UTRAN "P TMSI";
16 bits of the E UTRAN "M-TMSI" starting at bit 15 and down to bit 0 are mapped into bit 15 and down to bit 0 of the GERAN/UTRAN "P TMSI";
and the remaining 8 bits of the E UTRAN "M-TMSI" are mapped into the 8 MBS bits of the "P-TMSI signature" field.

Abbreviations Summary:
GUTI - Globally Unique Temporary UE Identity
GUMMEI - Globally Unique MME Identifier
MMEGI - MME Group ID
MMEC - MME Code
S-TMSI = SAE Temporary Mobile Subscriber Identity
M-TMSI = MME Temporary Mobile Subscriber Identity

Reference: 3GPP TS 23.003: Technical Specification Group Core Network and Terminals; Numbering, addressing and identification (Release 8) - Section 2.8

LTE device specs now made available by Verizon

Verizon is moving aggressively towards its plans for LTE and in this process the company released its initial set of technical specs for devices that will run on its Long Term Evolution (LTE) network, which Verizon will launch next year on a commercial basis.

The new specifications are designed to offer guidelines for both access and data transport for LTE devices and will serve as a roadmap for developers who choose to develop devices for submission to the LTE certification process.

The specifications can be downloaded from this link.

When you go on the link above you can see an invitation from that Verizon to join their LTE specification web Conference on May 13th for additional details and an opportunity to ask questions. The primary objective of this conference is to encourage developers to design devices that can take advantage of 4G network speeds and capabilities.

My Doggie Ring Ring

An employee of Japanese mobile phone carrier KDDI poses as she displays the company's new polka dot pattern mobile phone and dog-shaped phone holder designed by Japanese artist Yayoi Kusama in Tokyo.

The product named My Doggie Ring-Ring is priced at 1 million yen ($10,008) and will go on sale in Japan this summer for a limited edition of 100 sets.

Sci-Fi tech that we are still waiting for

Back in 1986, I used to subscribe to a magazine called '2001' which discussed about technologies of the future. One of the things I remember reading is that by 2001 we would have cars that would run on water and prototype of cars that would be able to fly. We are just starting to see cars that would work on hydrogen and emit water vapour. But its far from car that would work on water. We are still I would say long way away from prototype of flying cars.

IT PRO has an article on top 10 technologies we have been wishing for but not too close to reality yet. Have a look here.

Rough time for telcomm vendors but sees light ahead

There have been many reports over the past year about the recession and hence the effects on the telecomm companies.

The verdict was already out that the telecom equipment vendors are bracing for what is expected to be a fairly rough round of first-quarter earnings, with the global economic recession cutting into demand from both consumers and carriers alike, according to a report in the Wall Street Journal

The report also forecasted that some of the world's biggest European equipment vendors, found that while some would fare better than others, 2009 will generally be more difficult than 2008 for the companies.

Amid all these developments came the report yesterday when Nokia reported a worse-than-expected 90 per cent slump in first quarter profits.

This is Finnish mobile group's worst results since 2001 and rightly so, blamed on to the global economic downturn which has hit phone sales.

Mobile phone companies have been hit hard by a sharp drop in consumer spending. Nokia said it sold 93.2 million handsets during the first quarter, down 19 per cent from a year earlier and down 18 per cent from the fourth quarter.

Sony Ericsson, which has its headquarters in London, has also announced today that it’ll be slashing another 2,000 jobs around the world. The latest cost-cutting drive comes as the company posted a €293m (£258m) net loss for the first three months of the year.

However Nokia still maintained its market share which remained steady at 37 percent. The company also calmed jittery investors by reaffirming its prediction that the mobile market would shrink by 10 per cent this year, and the decline would level out in the second half of the year. It retained its operating margin forecast for its devices and services business.

Although the above news looks to be shocking but it didn’t stop the company’s shares to rise 9.5 per cent to €11.05 on the Helsinki stock exchange. The primary reason for the rise is that the investors were cheered by the company holding steady on its outlook after a grim quarter.
Similar to Nokia, Sony Ericsson too has vowed to return to profitability as quickly as possible thus calming the investors.

Like many other analysts especially in the financial world, telecom vendors like Nokia and Sony Ericsson too believe that there are nascent signs of relative stability going into the second quarter.

I still believe it’s a little bit too early to call a bottom on demand in the mobile devices business.

However most of the analysts expect that companies to return to profitability in the second half of 2010 thus showing a light at the end of the tunnel.

Black-listed and White-listed cells in E-UTRAN

One interesting thing done in LTE is that when System Information is transmitted, there is a list of cells known as ‘blacklisted’ cells. These black-listed cells can be Intra-frequency, Inter-frequency or Inter-RAT cells. These are the cells that UE should not consider while doing measurements, handovers or cell-reselections. The other list that the UE should consider is referred to as the white-list.

The black-listing is provided in the SystemInformationBlockType4 and SystemInformationBlockType5 that is transmitted by RRC in E-UTRAN.

By providing a black-list of the cells, the UE can avoid wasting time performing measurements on that frequency and then reading the System Information only to find out that there was no point of doing this operation. At the same time the neighbour list can be reduced and the amount of cells the UE reports in measurements can be reduced. The UE can also re-select to a new cell faster because the neighbour cell list size is reduced.

The possible reasons for black listing could be that a cell is reserved for operator then the UE's should not be able to use them. Similarly if the cell is reserved for future use or reserved for private use (Femtocells?) or in a scenario where it wont be possible for the UE to reselect it (Examples are cells that are separated by a river and micro cells that are in two different skyscrapers, etc).

I havent gone through the specifications in detail yet but it may be possible to use this information in case of Femtocells. The neighbouring Femto's can be included as black-listed cells so that the UE dont try to camp on them.

M is for Manga - Comics on the Mobile

The Independent newspaper has an interesting photo gallery on the Japanese Comics, better known as Manga. Check it out here.

LTE design requirements

There have been many discussions and articles written about LTE in the past one year or so. As LTE is pushing forward so is the design and implementation phase for different companies involved in LTE development. Following are the requirements for LTE which engineers should take into account while designing the LTE system.

Capabilities:
The targets for downlink and uplink peak data-rate requirements are 100 Mbit/s and 50 Mbit/s, respectively, when operating in 20 MHz spectrum allocation. For narrower spectrum allocations, the peak data rates are scaled accordingly. Thus, the requirements can be expressed as 5 bit/s/Hz for the downlink and 2.5 bit/s/Hz for the uplink. Obviously, for the case of TDD, uplink and downlink transmission cannot, by definition, occur simultaneously. Thus the peak data rate requirement cannot be met simultaneously. For FDD, on the other hand, the LTE specifications should allow for simultaneous reception and transmission at the peak data rates specified above. LTE should support at least 200 mobile terminals in the active state when operating in 5 MHz. In wider allocations than 5 MHz, at least 400 terminals should be supported.

System performance:
The LTE system performance design targets address user throughput, spectrum efficiency, mobility, coverage, and further enhanced MBMS.

The LTE user throughput requirement is specified at two points: at the average and at the fifth percentile of the user distribution (where 95 percent of the users have better performance). A spectrum efficiency target has also been specified, where in this context, spectrum efficiency is defined as the system throughput per cell in bit/s/ MHz /cell.

In terms of mobility LTE should be able to provide good rates even when the user is moving at 500km/h

Deployment-related aspects:
The deployment-related requirements include deployment scenarios, spectrum flexibility, spectrum deployment, and coexistence and interworking with other 3GPP radio access technologies such as GSM and WCDMA /HSPA.

The requirement on the deployment scenario includes both the case when the LTE system is deployed as a stand-alone system and the case when it is deployed together with WCDMA/HSPA and/or GSM. Thus, this requirement is not in practice limiting the design criteria.

The coexistence and interworking with other 3GPP systems and their respective requirements set the requirement on mobility between LTE and GSM, and between LTE and WCDMA/HSPA for mobile terminals supporting those technologies. Table below lists the interruption requirements, that is, longest acceptable interruption in the radio link when moving between the different radio-access.

Spectrum flexibility and deployment:
The basis for the requirements on spectrum flexibility is the requirement for LTE to be deployed in existing IMT-2000 frequency bands, which implies coexistence with the systems that are already deployed in those bands, including WCDMA/HSPA and GSM. A related part of the LTE requirements in terms of spectrum flexibility is the possibility to deploy LTE -based radio access in both paired and unpaired spectrum allocations that is LTE should support both Frequency Division Duplex (FDD), and Time Division Duplex (TDD).

Architecture and migration:
A few guiding principles for the LTE RAN architecture design as stated by 3GPP are:
A single LTE RAN architecture should be agreed.

The LTE RAN architecture should be packet based, although real-time and conversational class traffic should be supported.

The LTE RAN architecture should minimize the presence of ‘single points of failure’ without additional cost for backhaul.

The LTE RAN architecture should simplify and minimize the introduced number of interfaces.
Radio Network Layer (RNL) and Transport Network Layer (TNL) interaction should not be precluded if in the interest of improved system performance.

The LTE RAN architecture should support an end-to-end QoS. The TNL should provide the appropriate QoS requested by the RNL.

QoS mechanism(s) should take into account the various types of traffic that exists to provide efficient bandwidth utilization: Control-Plane traffic, User-Plane traffic, O & M traffic, etc.
The LTE RAN should be designed in such a way to minimize the delay variation (jitter) for traffic needing low jitter, for example, TCP/IP.

Radio resource management:
The radio resource management requirements are divided into enhanced support for end-to-end QoS, efficient support for transmission of higher layers, and support of load sharing and policy management across different radio access technologies.

The enhanced support for end-to-end QoS requires an ‘improved matching of service, application and protocol requirements (including higher layer signalling) to RAN resources and radio characteristics. ’ The efficient support for transmission of higher layers requires that the LTE RAN should ‘provide mechanisms to support efficient transmission and operation of higher layer protocols over the radio interface, such as IP header compression.’ The support of load sharing and policy management across different radio access technologies requires consideration of reselection mechanisms to direct mobile terminals toward appropriate radio access technologies in all types of states as well as that support for end-to-end QoS during handover between radio access technologies.

Complexity:
The LTE complexity requirements address the complexity of the overall system as well as the complexity of the mobile terminal. Essentially, these requirements imply that the number of options should be minimized with no redundant mandatory features. This also leads to a minimized number of necessary test cases.

General aspects:
The section covering general requirements on LTE address the cost-and service related aspects. Obviously, it is desirable to minimize the cost while maintaining the desired performance for all envisioned services. Specific to the cost, the backhaul and operation and maintenance is addressed.

QR Codes in Newspaper Ads to redirect mobiles to web content

Canada's National Post newspaper began using two-dimensional (2D) bar codes this week to link newspaper articles to video and other content.

The link from paper to the Web is made possible through a free downloadable mobile app for smartphones from Scanbuy, N.Y. Directions on nationalpost.com point visitors to getscanlife.com. When the camera on the phone takes a picture of the bar code, the application reads the embedded information in the code and triggers a Web browser to open, which searches the Internet for the URL and serves up the page on the phone.

National Post hopes to offer advertisers a print ad service that gives consumers options to discover more information about products and services on the Web, according to Scanbuy CEO Jonathan Bulkeley. He noted that Canwest Publishing is the largest media company in Canada.
The deal adds to the hundreds of thousands of people that have already downloaded software from Scanbuy's Web site during the last six months. "We're supporting hundreds of scans per day in the United States," Bulkeley said, suggesting that people can go to the site, create a 2D bar code and download it for free. "The codes are put on t-shirts and other marketing items to promote brands."

In the past few months, Scanbuy has signed deals with telecom carriers such as Alltel, before being acquired by Verizon, and Sprint, which will soon begin to ship handsets with the 2D bar code readers preloaded on phones. Today, the software is available to download on 45 phones. Nike ran a soccer promotion in Mexico, as did Fanta in Denmark and Scandinavia using 2D codes, Bulkeley said.

Bulkeley said he has been considering getting a 2D bar code tattoo to have something readily available that can demonstrate the technology. "You could have one code and continually change the link behind it to pull down different content," he said. "It's like redirecting a URL."

Watch the Video here:

Via: Daily Wireless

New Blogs on the Block

There are couple of blogs which I found useful and have been started this year.

3GPP Wireless Technology Demystified
This is by my colleague Venu Panchamukhi and its a very technical blog covering HSPA, HSPA+ (Release 7) and hopefully HSPA Evolution (Release 8) soon.

Wired n Wireless
This is another technical blog with focus on LTE with a mix of some other news.

If you are a new blogger and would like everyone to know about your blog then please feel free to add your blog in the comments. No Spam please as I am going to check each of the links before approving it. Also note that the blog should be related to telecoms, wireless, 3G, 4G, etc.