Thursday 30 April 2009

Speaking at the LTE World Summit 2009

I am going to be speaking in the LTE World Summit 2009 being held in Berlin, Germany from the 18th till the 20th May.

I am speaking at the Breakfast Briefing Session on the 20th morning at 8am. The topic of my speech is "Killer Devices or Killer Apps: Whats the key to success".

If you have any ideas or suggestions that you would like to share with me on the topic then I will be grateful. You can either email me directly (my first name dot my last name at yahoo dot com) or post in the comments section.

If you are coming to the event please feel free to drop an email. I have half a day on Sunday afternoon that I will probably spend looking around in Berlin. Any places in particular I should definitely see?

If you are interested in the details of the conference then you can check the brochure here.

Hoping to hear from many of you.

Wednesday 29 April 2009

Forum Oxford Conference 2009

The Forum Oxford Conference 2009 was held on 24th of April. Unfortunately I was unable to attend to report in detail what happened. This conference is close to my heart as its a hotbed for new and innovative ideas.

Here is a collection of blogs, etc. that cover this conference in detail. I will be adding more blogs when I find them:

Presentations from the conference:

Newspaper Articles:

Tuesday 28 April 2009

Simplified RRC in LTE as compared to UMTS

RRC states in LTE have been simplified. In case of UMTS there was a possibility of four states with complicated movements between them but in case of LTE, there is 'RRC Idle' and 'RRC Connected'.

Figure Source: Freescale White Paper

As in case of UMTS, in 'RRC_Idle' the main task of the RRC would be monitoring and cell/plmn selection. Everything else falls in 'RRC_Connected' state. The figure above shows RRC functions in both these states.

RRC Specs for LTE is 3GPP TS 36.331

Sunday 26 April 2009

SAE design targets

With SAE implementation in full swing around the world i thought it would be good idea to discuss some of the design targest for the SAE.

Following are the main targets for SAE design:

  • High-level user and operational aspects,
  • Basic capabilities,
  • Multi-access and seamless mobility,
  • Man–machine interface aspects,
  • Performance requirements for the evolved 3GPP system,
  • Security and privacy, and
  • Charging aspects.

Although the SAE requirements are many and split into the subgroups above, but as seen from the above points the SAE requirements are mainly non-radio access related.

The SAE system should be able to operate with more than the LTE radio access network and there should be mobility functions allowing a mobile terminal to move between the different radio-access systems. In fact, the requirements do not limit the mobility between radio access networks, but opens up for mobility to fixed-access network. The access networks need not to be developed by 3GPP, other non-3GPP access networks should also be considered. Thus the implementation for SAE should cover classes or functions for each handovers where the functions can be called as mobility functions.

The SAE requirements also list performance as an essential requirement but do not go into the same level of details as the LTE requirements. Different traffic scenarios and usage are envisioned, for example user to user and user to group communication. Furthermore, resource efficiency is required, especially radio resource efficiency (spectrum efficiency requirement for LTE). The SAE resource efficiency requirement is not as elaborated as the LTE requirement.
Thus it is the LTE requirement that is the design requirement.

Of course, the SAE requirements address the service aspects and require that the traditional services such as voice, video, messaging, and data file exchange should be supported, and in addition multicast and broadcast services. In fact, with the requirement to support IPv4 and IPv6 connectivity, including mobility between access networks supporting different IP versions as well as communication between terminals using different versions, any service based on IP will be supported

There is quality of service requirement of SAE is SAE system should for example, provide no perceptible deterioration of audio quality of a voice call during and following handover between dissimilar circuit switched and packet-switched access networks. Furthermore, the SAE should ensure that there is no loss of data as a result of a handover between dissimilar fixed and mobile access systems. A particular important requirement for the SAE QoS concept is that the SAE QoS concept should be backwards compatible with the pre- SAE QoS concepts of 3GPP. This is to ensure smooth mobility between different 3GPP accesses (LTE, WCDMA/HSPA and GSM).

The SAE system should provide advanced security mechanisms that are equivalent to or better than 3GPP security for WCDMA/HSPA and GSM. This means that protection against threats and attacks including those present on the Internet should be part of SAE. Furthermore, the SAE system should provide information authenticity between the mobile terminal and the network, but at the same time enable lawful interception of the traffic.

The SAE system has strong requirements on user privacy. Several levels of user privacy should be provided, for example communication confidentiality, location privacy, and identity protection. Thus, SAE -based systems will hide the identity of the users from unauthorized third parties, protect the content, origin and destination of a particular communication from unauthorized parties, and protect the location of the user from unauthorized parties. Authorized parties are normally government agencies, but the user may give certain parties the right to know about the location of the mobile terminal. One example hereof is fleet management for truck dispatchers.

Several charging models, including calling party pays, flat rate, and charging based on QoS is required to be supported in SAE. Charging aspects are sometimes visible in the radio access networks, especially those charging models that are based on delivered QoS or delivered data volumes. However, most charging schemes are only looking at information available in the core network.

Have phone, will talk!

Nice Collection of Photos on rediff with people on phones. Have a look here.

Saturday 25 April 2009

AT&T to do HSPA+ enhancement before adopting LTE

Before AT&T implements LTE, it plans another HSPA upgrade that will bring 3G capacity up to 7.2 Mb/s, says Telephony Magazine, using software enhancements to squeeze one last boost in bandwidth from its current high-speed packet access (HSPA) network. That will boost speeds from 3.6 megabits per second to 7.2 Mb/s, said Scott McElroy, AT&T Mobility vice president of technology.

In March AT&T announced plans to invest between US$17 billion and US$18 billion this year to, “extend and enhance wireless and wired broadband networks to provide more coverage, speed and capacity.”

AT&T currently has the enhanced networks running in two test markets but plans to extend those capabilities to its entire network, according to Telephony. Later this year, AT&T plans to start migrating its 3G networks to evolved-HSPA (or HSPA+), which would triple peak speeds.

AT&T, previously known as Cingular, launched its HSDPA network in 2005, supporting 1.8 Mb/s, but boosted that capacity to 3.6 Mb/s by 2008. Most of the laptop cards and smartphones AT&T sells, including the iPhone, have the silicon necessary to access that additional capacity. AT&T is now in the process of field certifying 7.2-Mb/s devices on its two test networks, McElroy said.

AT&T will most likely skip the final HSPA iteration of 14.4 Mbps, said McElroy, since HSPA+ is now ready for prime time. Evolved High-Speed Packet Access (also known as: HSPA Evolution, HSPA+, I-HSPA or Internet HSPA) is a wireless broadband standard defined in 3GPP release 7.

That could enable AT&T to go straight to 21 Mb/s. HSPA+ actually encompasses a bevy of upgrades, including evolving to a flat IP core and the introduction of smart antenna technology, but AT&T is focusing on upgrades to the baseband, which will dramatically increase capacity without having to fiddle with the elements on the tower or in the core.

Friday 24 April 2009

Innovative Designs and UI is the key to survival for Handset manufacturers

The smartphone segment of the market is poised for growth, just as a range of players are poised to release new smartphone devices in the months ahead. Among the most anticipated are new handsets based on Google's Android operating system, the next iteration of the iPhone, and the Palm Pre.

But as the number of smartphone makers proliferates, the need to create a differentiated product also increases. Much of that differentiation likely will come from the phone's user interface. Unfortunately for those in the market, it's difficult to deliver a phone with a compelling user interface that doesn't mimic all the other devices on the market.

The user interface has to be more than just a pretty face. It has to add value and ease of use for consumers. "It has to be a distinction that consumers value," said Avi Greengart, an analyst for Current Analysis. "Having a prettier set of animated weather cards isn't going to be enough."

Driving innovation may be too difficult a task for OEMs to accomplish in-house, according to John Jackson, vice president of research for CCS Insight. However, there are notable exceptions to this-HTC designed its TouchFlo3D UI in-house, and Samsung has latched onto its proprietary TouchWiz UI as the building block for its smartphones. Nevertheless, many handset makers are turning to outside firms to stay ahead of the innovation curve.

Companies such as TAT and Handmark have built their businesses around working with handset makers and operators on the user interface. TAT CEO Charlotta Falvin claims that her company's offerings sit on 10 percent of all mobile phones out on the market. Falvin said TAT's role in the design of UI is to bridge gaps between the desires and strategies of vendors and operators, a tricky proposition since operators, vendors and independent service providers all want a piece of real estate on the phone--and in consumers' minds.

"Nokia wants it to be a Nokia experience, Vodafone wants it to be a Vodafone experience and Facebook wants it to be a Facebook experience," she said. Success in creating a differentiated UI, however, will not be based around who is the first to market, or who makes the best partnerships, Falvin said, but on "who makes the best experience."

Handmark tries a similar approach. One of its main products is Pocket Express, a cross platform application that gives users access to news, sports, weather, stocks, travel and entertainment applications via a single interface. Wugofski said that the service has 2 million active users.

On the other hand, Daily Wireless argues that innovative designs and thinking out of the box may be key to success for the handsent manufacturers. There are lots of innovation happening around the 'fourth screen'.

OpenPeak has created a ‘fourth screen’ (after tv, computer and cell) for the home. It’s a hub that combines features of the telephone, TV, PC and cell phone into a compact, communications center.

The intuitive navigation menu on the 7? touchscreen makes it easy to make calls, play music, share photos, and organize your household. The device, powered by an Intel Atom processor, features 1GB of built-in storage, WiFi connectivity, an ethernet port, an audio out jack, and USB socket. It runs a cellular-branded version of the OpenFrame software, which appears to be based on Ubuntu linux. It is a wired device (no battery operation).

O2, a large cellular carrier in the UK is offering it to subscribers for £149.99 or free if taken instead of a handset when upgrading or signing a new 18 or 24 month contract. Its being marketed by the name Joggler.

The Verizon Hub is a home phone with an internet-connected base that offers users access to V Cast entertainment services, messaging, and email among other features. It will link up to an Application Store.

GiiNii plans to ship its Android-based portable media player and picture frame in October and January, respectively, according to a spokesperson. Archos announced an Android portable media player for mobile telephony.

Intel is now pushing Moblin V2 Core Alpha for Netbooks which should arrive in beta in May. It will now (apparently) take precedence over Moblin for MIDs, says Linux Devices, which is now postponed until 2010.

The UMPC Portal blog opines that MIDs based on Moblin 1.0, such as the BenQ S6 are being overwhelmed by the popularity of netbooks so abandoned MID developers might instead move to Android or even, gulp, Windows XP.

And ofcourse there are many other devices not mentioned here but please feel free to add them in the comments.

Thursday 23 April 2009

High speed Bluetooth officially announced

From its annual All Hands Meeting in Tokyo this week, the Bluetooth SIG formally adopted Bluetooth Core Specification Version 3.0 High Speed (HS), or Bluetooth 3.0. This latest iteration of the popular short-range wireless technology fulfills the consumers’ need for speed while providing the same wireless Bluetooth experience – faster. Manufacturers of consumer electronics and home entertainment devices can now build their products to send large amounts of video, music and photos between devices wirelessly at speeds consumers expect.

Bluetooth 3.0 gets its speed from the 802.11 radio protocol. The inclusion of the 802.11 Protocol Adaptation Layer (PAL) provides increased throughput of data transfers at the approximate rate of 24 Mbps. In addition, mobile devices including Bluetooth 3.0 will realize increased power savings due to enhanced power control built in.

On March 16, 2009, the WiMedia Alliance announced it is it will transfer all current and future specifications to Bluetooth, and the Wireless USB Forums. After completion of the technology transfer, the WiMedia Alliance will cease operations.

More than eight new Bluetooth enabled products are qualified every working day and more than 19 million Bluetooth units are shipping per week, says the Bluetooth SIG, with over two billion Bluetooth devices in the marketplace.

The Bluetooth SIG includes Promoter group companies Ericsson, Intel, Lenovo, Microsoft, Motorola, Nokia and Toshiba, along with over 11,000 Associate and Adopter member companies. The Bluetooth SIG, Inc. headquarters are located in Bellevue, Washington.

The next-generation Bluetooth is said to operate at similar distances (around 30 feet, best case) to today’s Bluetooth 2.0 but is a lot faster, capable of wireless transfers at a rate of 480Mbps. That’s the amazing 60MB per second, fast enough for high definition videoconferencing or moving files around at a fairly rapid clip.

That kind of speed blows the doors off Bluetooth 2.0, which pokes along at a mere 2.1 Mbps. The new Bluetooth gets its exponentially faster speed by teaming up with ultra wideband technology (UWB). But there are other contenders using similar tech such as Wireless USB (also 480Mbps), and it’s hard to tell how these various protocols will compete with each other, but for sure it is gonna be good for the consumers like us.


With the availability of Bluetooth version 3.0 HS, consumers can expect to move large data files of videos, music and photos between their own devices and the trusted devices of others, without the need for cables and wires. Some applications consumers will experience include:
  • Wirelessly bulk synchronize music libraries between PC and music player or phone
  • Bulk download photos to a printer or PC
  • Send video files from camera or phone to computer or television

Wednesday 22 April 2009

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.

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:
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
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
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

Tuesday 21 April 2009

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.

Monday 20 April 2009

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.

Sunday 19 April 2009

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.

Friday 17 April 2009

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.

Thursday 16 April 2009

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.

Wednesday 15 April 2009

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.

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.

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 point visitors to 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:

Tuesday 14 April 2009

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.

IMS Deployment and Future Strategy

A very interesting post by Christophe Gourraud in The IMS Lantern. If you are even remotely interested in IMS then you should read the post here.

Monday 13 April 2009

Qualcomm to put Femtocells in Mutant Animals ;)

In the latest breakthrough from its labs, Qualcomm has perfected a new version of its system-on-a-chip (SoC) technology that can be embedded into animals, turning them into living, breathing highly mobile femtocells. By creating biological femtocells, Qualcomm is allaying one of the critical weaknesses of the wireless network: while the devices on the network are mobile, the infrastructure of the network is static. By turning the family dog, for example, into a femtocell, the issues of dead zones and coverage gaps disappear as coverage moves with you wherever you—and your dog—go.

Research into these dynamic biological networks is still in its infancy, but Qualcomm has released a demo video on the technology, which you can view below. As part of that research, Qualcomm is trying to overcome what it sees as the inherent limitations of many species of animals. Pigeons, for instance, could be used to create a pervasive flying network in any heavily trafficked downtown area, but the pigeon isn’t the most long-lived of animals and it has several predators, thus requiring an operator to constantly reintroduce new pigeons into the network to maintain capacity levels.

Qualcomm has solved that problem through genetic engineering. It has crossbred a pigeon with a wolf, creating a hardier more aggressive femtocell that can defend itself from both predators and the elements. The only problem with this approach, though, is its high susceptibility to industrial espionage. A rival operator could introduce biological femtocell predators into a market, to attack, maim and possible even eat another operator’s femtocells. While bio-engineering femtocells such as the wolf-pigeon might seem a natural defense mechanism against tactics, the rival operator could always engineer a better femtocell. Qualcomm demonstrated how a shark crossbred with a hawk could effectively nullify a femtocell networks composed of wolf pigeons.

See the Video below:

By the way, I hope you have realised that it was an April Fools joke :)

Sunday 12 April 2009

Mobile Screensaver helps catch a burglar

This story can probably be nominated for the most stupid awards.

A bungling burglar was caught out after he left his mobile phone - with a picture of himself on the screen - in a house he had broken into, police said.

Richard Hannah was jailed for six years today after he was found guilty of burglary by a jury at Nottingham crown court.

Hannah, 30, was confronted by the owner of a house in Mansfield Woodhouse, Nottinghamshire, after he broke in at about 4am on 15 September last year.

After a scuffle between the pair, Hannah, from Poplar Street, Mansfield Woodhouse, left his mobile phone, with a screensaver photo of himself, at the house.

Hannah was found guilty today of burglary after a three-day trial, despite claiming the phone had been stolen and left by someone else.

He was jailed for six years under the government's "three strikes and you're out" crackdown, Nottinghamshire police said.

Saturday 11 April 2009

Future Phones will be able to understand your thoughts

Honda is working on a technology for Robots in Japan where they can understand the owners thoughts. Right now only four commands can be understood but the success rate is 90%. If this technology becomes successful it can probably be applied to phones as well.

I remember reading (cant find link, sorry) that NTT DoCoMo has already developed a prototype of phone in which you can speak without any sound and the person at the other end wont even notice. He will hear normal voice.

NTT DoCoMo launched Motion sensing phones couple of years back and the main idea was that the user can control things by motion of their hands. I havent dug into details but I can visualise myself in future working on my laptop and just by waving my hand ask my mobile to start composing a text message. I would be able to dictate the message and just with another wave of my hand, the message will be sent.

Japan has always been the leader of these kinds of technologies and companies out there are working hard innovating new technology. NTT DoCoMo (again) showed off last year a technology where the volume can be controlled just by rolling the eyes. At the moment all these things involve some kind of human attachment which makes them impractical for the time being. In future hopefully there will be better alternatives and more reliable technologies like these.

Anyway, we wont see any of the above technologies anytime soon. There is a funny video on Youtube that you will like about these future technologies that is available below:

Friday 10 April 2009

HSPA based Laptop Enabler/Disabler

Ericsson (NASDAQ:ERIC) today unveiled its most advanced mobile broadband module, uniquely designed with innovative features to provide a richer and cost-effective internet experience for all. The next-generation module marks the latest milestone for Ericsson, furthering the company's vision of an all-connected world.

Ericsson's F3607gw mobile-broadband module for HSPA/GPRS/EDGE networks, to be released in June, will provide enhanced functionality and convenience through its innovative features, reduced power consumption, prolonged battery life and an increased level of integration, reducing the number of necessary components and therefore cost. The new module will also provide built-in mobile broadband support for Microsoft Windows 7.

Mats Norin, Vice President of Ericsson Mobile Broadband Modules, says: "The combination of leading technology and innovative design in the next-generation module is key to delivering a superior user experience at an affordable price. This module release confirms Ericsson's commitment to making the benefits of connectivity available to everyone."

An important facet of the F3607gw is the unique wake-on wireless feature. By remaining connected while a notebook or netbook is in sleep mode, the module's wake-on wireless feature enables users to remotely wake up the device. This innovative technology will allow a new set of applications to be built into the computer to further enhance security and instant-on functionalities, such as the ability to disable the computer in case of theft, or instant distribution of important messages and security updates.

Operators can also combine the wake-on wireless feature and embedded GPS functionality to create a range of differentiating services for consumers and the enterprise market, including remote manageability, security updates, asset protection and tracking and geo-fencing. The module can also be used for content push services, such as podcasts, public warnings, traffic updates and database updates.

Specifically, the wake-on wireless feature supports security solutions based on Intel's Anti-Theft PC Protection Technology. An anti-theft management service in the network can send a message via SMS to the mobile-broadband module inside the notebook, which securely transfers the message to Intel's Anti-Theft function inside the processor platform. This takes appropriate actions, such as completely locking the computer and making it unusable. When the notebook is located and recovered, an unlock message can be sent to the notebook that makes the data accessible again.

Thursday 9 April 2009

Anritsu's LTE Tester MD8430A is a winner

Anritsu Company announces its MD8430A Signalling Tester was the only test instrument to win a prestigious CTIA Emerging Technology (E-Tech) Award, announced during the International CTIA WIRELESSS® 2009 show in Las Vegas. The MD8430A, the industry’s first LTE base station simulator, earned a second prize in the 4G - Service Creation & Development category of the E-Tech Awards, which recognize the finest wireless products and services.

“We are thrilled and honored to have won a CTIA E-Tech award because it signifies the best and brightest technologies in the wireless market. We would like to thank everyone who participated in the voting and supported the MD8430A,” said Wade Hulon, Vice President and General Manager of Anritsu Company, Americas Sales Region. “The MD8430A is being used by LTE chipset manufacturers to ensure the quality of their products, speed time to market, and reduce design and production test costs.”

Approximately 300 entries were received for this year’s E-Tech Awards. They were reviewed by a panel of 30 recognized members of the media, industry analysts and executives who selected finalists based on innovation, functionality, technological importance, implementation and overall “wow” factor. More than 40,000 wireless professionals voted on the finalists to determine the winners in 18 categories.

The MD8430A is a highly accurate cost-effective solution for manufacturers of LTE chipsets and mobile devices to evaluate their products and improve time to market. Developed in conjunction with leading chipset manufacturers, the MD8430A augments Anritsu’s broad 3GPP test suite, providing developers of wireless devices and systems with a single-source test solution company.

The MD8430A is designed with 4 RF units that enable 2x2 MIMO system handover tests in a simulated network environment. The base station simulator can conduct end-to-end testing at downlink speeds up to 150 Mbps and uplink speeds up to 50 Mbps. All critical 3GPP air-interface LTE protocol tests, including baseband coding/decoding processing tests; protocol sequence tests, such as position registration, origination, termination, handover, terminal and network disconnect tests; and application tests, are supported. Powerful L1/L2 cache analysis functions are provided as well.

Presentations on Mobile Apps

There are couple of interesting Mobile App related discussions in Forum Oxford recently, for anyone interested:

An interesting presentation on Application Stores and Mobile Social Media by Cedric Giorgi is available on SlideShare.

Another one titled, The App store and Future of Mobile Applications by William Volk is available on Slideshare as well.

William has also started an interesting discussion where he makes an interesting point:

In the case of the Android App Market, paid app sales are a fraction of what one would expect. The top paid apps have sold only a few 1000 copies, free apps have reached download numbers of over 250,000.

Why? Most users have not opted-in to Google Checkout, which is the billing system used.

Apple, of course, requires users to opt into iTunes, but iTunes already has widespread acceptance. 93% of iPhone users have purchased an app.

My understanding is that Google approached T-Mobile about this and the idea of adding carrier billing as an option was rejected.

So let me get this straight:
1. Apple cleverly cuts operators out of the app revenue stream.
2. Competing 'open' platform, Android appears.
3. Operators reject Google's offer to use their billing systems for app purchases.
4. Operators see no revenue from app sales on iTunes AND Android App Marketplace.
5. Android is a non-starter for app developers in business terms.
The question is, will users opt in for PayPal when the RIM App World turns on?

You can follow the discussion here.

Wednesday 8 April 2009

More than 1 Trillion messages were sent in 2008

CTIA -The Wireless Association® announced the findings of its semi-annual industry survey, which includes numerous positive metrics on the industry’s continued growth and popularity. In particular, wireless revenues showed impressive year-to year gains, as wireless data service revenues for the year 2008 rose to more than $32 billion. This represents a 39% increase over 2007, when data revenues totaled $23.2 billion. Wireless data revenues for 2008 amounted to nearly 22% of all wireless service revenues, and represent what consumers spend on non-voice services.

According to the survey, text messaging continues to be enormously popular, with more than one trillion text messages carried on carriers’ networks in 2008—breaking down to more than 3.5 billion messages per day. That’s almost triple the number from 2007, when 363 billion text messages were transmitted. Wireless subscribers are also sending more pictures and other multi-media messages with their mobile devices, with 15 billion MMS messages reported for 2008, up from 6 billion the year before.

According to the survey, text messaging continues to be enormously popular, with more than one trillion text messages carried on carriers’ networks in 2008—breaking down to more than 3.5 billion messages per day. That’s almost triple the number from 2007, when 363 billion text messages were transmitted. Wireless subscribers are also sending more pictures and other multi-media messages with their mobile devices, with 15 billion MMS messages reported for 2008, up from 6 billion the year before.

As of December 2008, the industry survey recorded more than 270 million wireless users. This represents a year-over-year increase of nearly 15 million subscribers. The industry’s 12-month record for subscriber growth was reached in 2005, when 25.7 million new users came online.
Other highlights of the survey include: wireless customers using more than 2.2 trillion minutes in 2008, an increase of 100 billion minutes from 2007, and record-breaking six-month wireless service revenues of more than $75 billion with annual service revenues reaching $148 billion by year-end 2008.

The CTIA Semi-Annual Wireless Industry Survey results were released on 1st April 2009 at International CTIA WIRELESS 2009®. Billed as the most important global technology event of the year, with more than 1,200 exhibiting companies and around 40,000 attendees from 125 countries, it took place April 1st -3rd at the Las Vegas Convention Center in Las Vegas, Nevada.

According to another survey in Canada, relationships often blossom thanks to technology. Two in five (42%) of Canadians aged 18-34 would send a flirtatious text to hint they have a crush. Youth are also significantly more inclined to flirt with their crush using Facebook wall posts or gifts (35%) and instant messaging (32%). On the other hand, just over one in ten Canadians aged 55+ would use Facebook (15%) and instant messaging (12%).

Results also show Canadians are doing everything from flirting to breaking up, all using technology. Surprisingly, a full 10 per cent of Canadians would give someone the hint that their relationship is over by changing their Facebook status. When it comes to breaking up the old fashioned way, 35 per cent of Canadians would choose to break up with someone over the phone or in person and only 10 per cent would opt not to use technology to get this message across.

Sunday 5 April 2009

Orthogonality and non orthogonality

Multiple access (MA) is a basic function in wireless cellular systems. Generally speaking, MA techniques can be classified into orthogonal and non-orthogonal approaches. In orthogonal approaches, signals from different users are orthogonal to each other, i.e., their cross correlation is zero, which can be achieved by time division multiple-access (TDMA), frequency-division multiple-access (FDMA) and orthogonal-frequency division multiple-access (OFDMA). Non-orthogonal schemes allow non-zero cross correlation among the signals from different users, such as in random waveform code-division multiple-access (CDMA), trellis-coded multiple-access (TCMA) and interleave-division multiple-access (IDMA).

First and second generation cellular systems are dominated by orthogonal MA approaches. The main advantage of these approaches is the avoidance of intra-cell interference. However, careful cell planning is necessary in these systems to curtail cross-cell interference. In particular, sufficient distance must exist between re-used channels, resulting in reduced cellular spectral efficiency.

Non-orthogonal CDMA techniques have been adopted in second and third generation cellular systems (e.g. CDMA2000 and uplink WCDMA). Compared with its orthogonal counterparts, CDMA is more robust against fading and cross-cell interference, but is prone to intracell interference. Due to its spread-spectrum nature, CDMA is inconvenient for data services (e.g., wireless local area networks (WLANs) and 3GPP high speed uplink/downlink packet access (HSUPA/HSDPA) standard) that require high single-user rates.

Communication services can be classified into delay sensitive and insensitive ones. A typical example of a delay-insensitive service is email. Typical examples of delay-sensitive services include speech and video applications. For delay insensitive services, rate constraints are relatively relaxed for individual users and maximizing the throughput by orthogonal methods is a common strategy. The maximum throughput can be achieved by a one-user transmission policy, where only the user with the largest channel gain is allowed to transmit. This implies time domain orthogonality as adopted in many WLANs. For delay-sensitive services, on the other hand, each user must transmit a certain amount of information within a certain period and maximizing the throughput is no longer an appropriate strategy. Rate constraints must be considered in this case.

CDMA is the most well known non-orthogonal technique. The main advantages of CDMA are its robustness against fading and cross-cell interference, and its flexibility in asynchronous transmission environments.
An uplink data transfer mechanism in the HSUPA is provided by physical HSUPA channels, such as an Enhanced Dedicated Physical Data Channel (E-DPDCH), implemented on top of Wideband Code Division Multiple Access (WCDMA) uplink physical data channels such as a Dedicated Physical Control Channel (DPCCH) and a Dedicated Physical Data Channel (DPDCH), thus sharing radio resources, such as power resources, with the WCDMA uplink physical data channels. The sharing of the radio resources results in inflexibility in radio resource allocation to the physical HSUPA channels and the WCDMA physical data channels. In CDMA, which is a non-orthogonal multiple access scheme, the signals from different users within the same cell interfere with one another. This type of interference is known as the intra-cell interference. In addition, the base station also receives the interference from the users transmitting in neighbouring cells. This is known as the inter-cell interference.

Uplink power control is typically intended to control the received signal power from the active user equipments (UEs) to the base as well as the rise-over-thermal (RoT), which is a measure of the total interference (intra- and inter-cell) relative to the thermal noise. In systems such as HSUPA, fast power control is required due to the fast fluctuation in multi-user (intra-cell) interference. This fast fluctuation will otherwise result in the well-known near-far problem. Moreover, as uplink transmission in an HSUPA system is not orthogonal, the signal from each transmitting UE is subject to interference from another transmitting UE. If the signal strength of UEs varies substantially, a stronger UE (for example, a UE in favourable channel conditions experiencing a power boost due to constructive short term channel fading such as Rayleigh fading) may completely overwhelm the signal of a weaker UE (with signal experiencing attenuation due to short term fading). To mitigate this problem, fast power control has been considered previously in the art where fast power control commands are transmitted from a base station to each UE to set the power of uplink transmission.

When an orthogonal multiple access scheme such as Single-Carrier Frequency Division Multiple Access (SC-FDMA), which includes interleaved and localized Frequency Division Multiple Access (FDMA) or Orthogonal Frequency Division Multiple Access (OFDMA), is used, multi-user interference is not present for low mobility and small for moderate mobility. This is the case for the next generation UMTS i.e. LTE system. LTE system employs SC-FDMA in uplink and OFDMA in downlink. As a result in the case of LTE, the fluctuation in the total interference only comes from inter-cell interference and thermal noise which tends to be slower. While fast power control can be utilized, it can be argued that its advantage is minimal. Hence, only slow power control is needed for orthogonal multiple access schemes.

Nokia's Point, Click, Find

Nokia launches beta of 'Point & Find' system for mobile phones, letting consumers scan images for search with their camera phone.

The service can currently be downloaded in the US and the UK, on selected handsets. The phones supported by the current beta are the Nokia N82, N95, E66, N81, N76, E51, 6290, 6124 Classic, 6121 Classic, 6110 Navigator, and the 5700 Xpress Music.

Nokia has launched a beta of its new Point & Find system, which lets mobile phone users search for information on an object by looking at it with their handset camera.

Philipp Schloter, Nokia’s general manager for Point & Find, explained: "Simply by pointing their camera phone at a poster for a new movie, people can watch the trailer, read reviews, and find the closest cinema where it is playing.”

Other uses suggested by Nokia include scanning barcodes for prices, looking at items for sale and being sent more details on where to shop or coupons, or eyeing objects in a museum and being sent multimedia information about it.

The open platform system uses the camera to look at images, GPS positioning to decide where it is, and the internet to search though a database of tagged objects. When an image is recognised, links to content – such as film times or prices – are sent back to the user.

Nokia doesn’t just want consumer feedback, but is looking to hear from businesses about their ideas for the tech – click here for the Point & Find business site. It’s already being used by the Body Worlds exhibition at the O2 in London, so pointing the camera of a Point & Find phone at related advertising should bring up data on the show.

Saturday 4 April 2009

Sonim XP1: The toughest phone

This is billed as the toughest phone ever built:
  • Water/Humidity: Impervious to the Wettest Weather
  • Temperature Range: Works Perfectly In Extreme Conditions (-20C to +60C )
  • Shock and Vibration: Drop It, Abuse It, Drive Over It – No Problem! The XP1 is Virtually Indestructible
  • Screen: Unique No-Glare Coating Resists Scratches and Smudges
  • Durable Case: Hardened Rubber Molding Cast Via Dual Injection
  • Durable Mechanics: Keypad Buttons Tested To 500,000 Pushes Dedicated PPT Buttons Tested To 200,000 Pushes
  • Dirt and Dust: Non-Porous Casing Blocks Entry of Micro-Particles
Comes with 3 years guarantee
Selling in UK for £249.00
Official website here.

Friday 3 April 2009

Nokia favours LTE by dismissing WiMax

In the past few days the argument between WiMax and LTE camp has intensified. Both the camps are grabbing every single opportunity to pass disparaging remarks over the other. Evidently both WiMax and LTE are trying to be 4G bearer and in order to do so they are just pushing things to the limit.

It’s very well known that Nokia although has chosen LTE as their 4G technology, are still part of WiMax forum.

However what is astonishing is that Nokia has now strongly come out openly to dismiss WiMax as a 4G technology. This latest development will no doubt will generate some intensifying and interesting comments from both the camps.

Nokia by dismissing WiMAX as a 4G technology standard seemed to have solidified its support for Long Term Evolution (LTE) technology while comparing WiMAX's future to that of Betamax, the video format that met its demise when VHS triumphed in the 1970s and 1980s. In a recent Nokia launch event in San Francisco Anssi Vanjoki, Nokia's head of sales and manufacturing said the following:
"I don't see that WiMAX is taking hold anywhere in a big way. I don't think the future is very promising for WiMAX. This is a classic example of industry standards clashing, and somebody comes out as the winner and somebody has to lose. Betamax was there for a long time, but VHS dominated the market. I see exactly the same thing happening here."

The words above are really strong as far as dismissing WiMax as a 4G technology is concerned.

Nokia has wavered in its support for WiMAX in the past, but this is by far the strongest condemnation the world's largest handset maker has made of the technology. Nokia quite rightly present WiMAX's lack of backwards compatibility as one of the reasons why they think LTE is the future and for that very reason call WiMAX a niche play.

However it still remains to be seen whether Nokia is completely abandoning WiMax as it is still involved in WiMAX business development efforts.

Albeit it is still an immense argument as what will be 4G. Clearly from the dominant mobility operator perspective the trend is towards LTE. Any technology that gets rolled out has to provide global backwards compatibility because networks don't appear overnight. The only technology that offers you backward compatibility to CDMA and TD-CDMA and wideband-CDMA is LTE. It makes a huge difference because you're not building greenfield networks; these are evolutions of existing networks and the user experience has to be maintained. From that perspective, WiMAX doesn't quite have the same capability.

I don’t want to sound too harsh on WiMax and I think there might be a place for WiMAX as a fourth generation niche technology but I believe over time, LTE will be the standard bearer for 4G globally. The (WiMAX) technology itself, there's nothing wrong with it; it's strong and it ultimately will work. The question is whether there will be a market.

More on ICE

Continuing from the earlier post on ICE, Martin Sauter has some more information on this topic:

During the Mobile World Congress in Barcelona this year, I heard from Adrian Scrase for the first time that 3GPP has specified how to put information on the SIM card for "In Case of Emergency" (ICE) events, i.e. to help first responders to identify someone and to contact their next of kin.

A great idea and now that it is specified it will hopefully become a worldwide accepted feature. It's not in current phones and SIM cards yet so it will take a couple of years for the feature to be added. Let's keep our fingers crossed a critical mass is reached so people actually enter information and first responders actually use the feature.

As somebody asked me over at Forum Oxford at how it will work in practice, I've had a look at the standards:
  • The user enters ICE information like names of persons, relation to these persons and phone numbers. For details see 3GPP TS 22.101, A28
  • During an emergency, the information can be retrieved by pressing '* * *'. That's specified in 3GPP TS 22.030, 6.8
  • The information is stored in a new file on the SIM card referred to as EF(ICE_DN) and the format is described in 3GPP TS 31.102

Thursday 2 April 2009

Fundamental difference between HSDPA and HSUPA

It has been long time since HSDPA and HSUPA came into existence. Untill now we have read and implemented many features related to HSDPA and HSUPA. However following are the basic difference between HSDPA and HSUPA:
  • In the downlink, the shared resource is transmission power and the code space, both of which are located in one central node, the NodeB. In the uplink, the shared resource is the amount of allowed uplink interference, which depends on the transmission power of multiple distributed nodes, the UEs.
  • The scheduler and the transmission buffers are located in the same node in the downlink, while in the uplink the scheduler is located in the NodeB while the data buffers are distributed in the UEs. Hence, the UEs need to signal buffer status information to the scheduler.
  • The WCDMA uplink, also with Enhanced Uplink, is inherently non-orthogonal, and subject to interference between uplink transmissions within the same cell. This is in contrast to the downlink, where different transmitted channels are orthogonal. Fast power control is therefore essential for the uplink to handle the near-far problem. The E-DCH is transmitted with a power offset relative to the power-controlled uplink control channel and by adjusting the maximum allowed power offset, the scheduler can control the E-DCH data rate. This is in contrast to HSDPA, where a (more or less) constant transmission power with rate adaptation is used.
  • Soft handover is supported by the E-DCH. Receiving data from a terminal in multiple cells is fundamentally beneficial as it provides diversity, while transmission from multiple cells in case of HSDPA is cumbersome and with questionable benefits as discussed in the previous chapter. Soft handover also implies power control by multiple cells, which is necessary to limit the amount of interference generated in neighbouring cells and to maintain backward compatibility and coexistence with UE not using the E-DCH for data transmission.
  • In the downlink, higher-order modulation, which trades power efficiency for bandwidth efficiency, is useful to provide high data rates in some situations, for example when the scheduler has assigned a small number of channelization codes for a transmission but the amount of available transmission power is relatively high. The situation in the uplink is different; there is no need to share channelization codes between users and the channel coding rates are therefore typically lower than for the downlink. Hence, unlike the downlink, higher order modulation is less useful in the uplink macro-cells and therefore not part of the first release of enhanced uplink.