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Sunday, 27 July 2008

Adaptive Antenna System

Whenever we talk about the evolution of new technology in telecoms world one thing which always occupy the prominent position is the spectral efficiency. The success and efficiency of any wireless system depends on the spectral efficiency.

What is spectral efficiency though?

Spectral efficiency can be defined as bits/seconds/Hz/cell. It measures how well a wireless network utilizes radio spectrum and also determines the total throughput each base station (cell) can support in a network in a given amount of spectrum.

There is no doubt that if a new air interface is to be build it should be built from the ground up to be optimized for spatial processing. Spectral efficiency directly affects an operator’s cost structure. For a given service and grade of service, it determines the following:
  • Required amount of spectrum (CapEx),
  • Required number of base stations (CapEx, OpEx),
  • Required number of sites and associated site maintenance (OpEx), and,
  • Ultimately, consumer pricing and affordability

Spectral efficiency will become even more important as subscriber penetration increases, per-user data rates increase and the as quality of service (esp. data) requirements increase.

There are so many elements for design to achieve high spectral efficiency. Adaptive Antenna System (AAS) is one of the methods to achieve high spectral efficiency.

Adaptive Antenna System (AAS) provides gain and interference mitigation leading to improved signal quality and spectral efficiency.

The use of adaptive antenna systems enables the network operators to increase the wireless network capacity, where such networks are expected to experience an enormous increase in the traffic. This is due to the increased number of users as well as the high data rate service and applications. In addition, adaptive antenna systems offer the potential of increased spectrum efficiency, extended range of coverage and higher rate of frequency reuse.

Adaptive antenna systems consist of multiple antenna elements at the transmitting and/or receiving side of the communication link, whose signals are processed adaptively in order to exploit the spatial dimension of the mobile radio channel. Depending on whether the processing is performed at the transmitter, receiver, or both ends of the communication link, the adaptive antenna technique is defined as multiple-input single-output (MISO), single-input multiple-output (SIMO), or multiple-input multiple-output (MIMO).

Multipath propagation, defined as the creation of multipath signal paths between the transmitter and the receiver due to the reflection of the transmitted signal by physical obstacles, is one of the major problems of mobile communications. It is well known that the delay spread and resulting inter symbol interference (ISI) due to multiple signal paths arriving at the receiver at different times have a critical impact on communication link quality. On the other hand, co-channel interference is the major limiting factor on the capacity of wireless communication systems, resulting from the reuse of the available network resources (e.g., frequency and time) by a number of users.

Adaptive antenna systems can improve link quality by combining the effects of multipath propagation or constructively exploiting the different data streams from different antennas. More specifically, the benefits of adaptive antennas can be summarized as follows:

  • Increased range/coverage: the array or beam forming gain is the average increase in signal power at the receiver due to a coherent combination of the signal received at all antenna elements. The adaptive antenna gain compared to a single element antenna can be increased by an amount equal to the number of array elements, e.g., an eight element array can provide a gain of eight (9 dB).
  • Increased Capacity: One of the main reasons of the growing interest of adaptive antennas is the capacity increase. In densely populated areas, mobile systems are normally interference-limited; meaning that interference from other users is the main source of noise in the system. This means that the signal to interference ratio (SIR) is much larger than the signal to thermal noise ratio (SNR). Adaptive antennas will on average, increase the SIR. Experimental results report up to 10 dB increase in average SIR in urban areas. For UMTS networks, a fivefold capacity gain has been reported for CDMA.
  • Lower power requirements and/or cost reduction: Optimizing transmission toward the wanted user achieves lower power consumption and amplifier costs.
  • Improved link quality/reliability: Diversity gain is obtained by receiving independent replicas of the signal through independently fading signal components. Based on the fact that one or more of these signal components will not be in a deep fade, the availability of multiple independent dimensions reduces the effective fluctuations of the signal.
  • Increased spectral efficiency: Spectral efficiency is a measure of the amount of information –billable services- that carried by the wireless system per unit of spectrum. It is measured in bits/second/Hertz/cell, thus it includes the effect of multiple access methods, modulation methods, channel organization and resource reuse (e.g., code, timeslot, carrier). Spectral efficiency plays an important role since it directly affects the operator cost structure. Moreover, for a given service and QoS, it determines the required amount of spectrum, the required number of base stations, the required number of sites –and associated site maintenance-, and ultimately, consumer pricing and affordability. Equation (1) shows a simplified formula to estimate the required number of cells per square kilometer. (the offered load is in bits/seconds/km2).
  • Security: It is more difficult to tap a connation, since the intruder has to be position himself in the same direction of arrival as the user.
  • Reduction of handoff: there is no need for splitting the cells for the sake of capacity increase, and in consequence less amount of handoff.
  • Spatial information: the spatial information about the user would be available at any given time, which enables the introduction of Location Based Services.

In addition to the above-mentioned benefits and liken any other systems AAS has got it’s own drawbacks as well. One must point out the following drawbacks (or costs) of the adaptive antennas:

  • Transceiver Complexity: It is obvious that the adaptive antenna transceiver is much more complex than the conventional one. This comes from the fact that the adaptive antenna transceiver will need separate transceiver chains for each of the array elements and accurate real-time calibration of each of them.
  • Resource Management: Adaptive antennas are mainly a radio technology, but they will also put new demands on network functions such as resource and mobility management. When a new connection is to be set up or the existing connection is to be handed over to a new base station, no angular information is available to the new base station and some means to “find” the mobile station is necessary.
  • Physical Size: For the adaptive antenna to obtain a reasonable gain, an array antenna with several elements is necessary. Typically arrays are consisting of six to ten horizontally separated elements have been suggested for outdoor mobile environments. The necessary element spacing is 0.4-0.5 wavelengths. This means that an eight-element antenna would be approximately 1.2 meters wide at 900 MHz and 60 cm at 2 GHz. With a growing public demand for less visible base stations, this size, although not excessive, could provide a problem.

An Adaptive Antenna System (AAS) can focus its transmit energy to the direction of a receiver. While receiving, it can focus to the direction of the transmitting device. The technique used in AAS is known as beamforming or beamsteering or beamshaping. It works by adjusting the width and the angle of the antenna radiation pattern (a.k.a. the beam). Combined with multiple antennas in the Base Station (BS), AAS can be used to serve multiple Subscriber Stations (SSs) with higher throughput. A technique known as SDMA (Space Division Multiple Access) is employed here where multiple SSs that are separated (in space) can transmit and receive at the same time over the same sub-channel.

AAS also eliminates interference to and from other SSs and other sources by steering the nulls to the direction of interferers.AAS is feature suits very well for LTE and it is an optional feature in WiMAX as it yet to be included in WiMAX certification. But due to its effectiveness in improving performance and coverage especially in Mobile WiMAX case, many vendors integrate AAS capability into their products.

Saturday, 26 July 2008

USSD: Old is Gold

Even though there are so many new technologies available for creating mobile applications, there is still a market for the old fashioned USSD applications.

USSD or Unstructured Supplementary Service Data is a capability of all GSM phones. It is generally associated with real-time or instant messaging type phone services. There is no store-and-forward capability that is typical of 'normal' short messages (in other words, an SMSC is not present in the processing path). Response times for interactive USSD-based services are generally quicker than those used for SMS.

A sample USSD service is the bill status service accessed by dialing *141# or similar numbers in between * and #. USSD applications can be thought of as an IVRS (Interactive Voice Response System) with out voice.

Some of the USSD applications that we use regularly are:
  • Alerts About special offers, services and news
  • Balance enquiry
  • Changing tariff plan and subscribing to various VAS services.
  • Recharging using prepaid vouchers

Other than these many interesting services can be given using the USSD platform. One such service is the “call back” service. The user will use USSD to send a USSD message to his friend asking him to call back. This is done by pressing the USSD service number and the number to which the alert needs to be send. Assume 14 is the service number and you want me to call you back. Press this on your mobile and press dial.

*14*9846831128#

I will receive a message, “XXXXXXXXXX wants you to call him back” where XXXXXXXXXX will be your number.

Barclays has started a Hello Money service in India. This is a USSD based service and quick demo can be viewed here.

A similar service is being tested in Kenya called Commerce 360. Commerce 360 will link banks, utility services and other companies with the mobile phone owners. Other than Kenya, Cellulant which is one and half year old has subsidiaries in Uganda, Tanzania and Nigeria in which it intends take the Commerce 360 mobile banking solution if it succeeds in the Kenyan market.

Finally if interested here is a youtube video from late early 2000's showing USSD in practice.


Friday, 25 July 2008

Spying: Bluetooth style

According to a security expert, writing in Cnet:

Bluetooth headset users are at risk because of a security hole in the technology and default PINs that don't get changed, he said. Exploiting vulnerabilities someone can break in and steal data from the phones, make calls without the cell phone owner knowing, listen in on and break into conversations, and even spy on people by turning the device into a bug. He advises that people change the default password, disable the Bluetooth on the phones, turn off the headsets when not in use, and limit access to the data and features when communicating with other Bluetooth devices.

There may be more reasons to switch Bluetooth off.

According to an article in Guardian:

Tens of thousands of Britons are being covertly tracked without their consent in a technology experiment which has installed scanners at secret locations in offices, campuses, streets and pubs to pinpoint people's whereabouts.

The scanners, the first 10 of which were installed in Bath three years ago, are capturing Bluetooth radio signals transmitted from devices such as mobile phones, laptops and digital cameras, and using the data to follow unwitting targets without their permission.

The data is being used in a project called Cityware to study how people move around cities. But pedestrians are not being told that the devices they carry around in their pockets and handbags could be providing a permanent record of their journeys, which is then stored on a central database.

The Bath University researchers behind the project claim their scanners do not have access to the identity of the people tracked.

Although initially confined to Bath, Cityware has spread across the planet after the software was made freely available on the internet sites Facebook and Second Life. Thousands of people downloaded the software to equip their home and office computers with Cityware scanners.

More than 1,000 scanners across the world at any time detect passing Bluetooth signals and send the data to Cityware's central database. Those with access to the database admit they do not know precisely how many scanners have been created, but there are known to be scanners in San Diego, Hong Kong, Australia, Singapore, Toronto and Berlin.

In Bath alone scanners are tracking as many as 3,000 Bluetooth devices every weekend. One recent study used the scanners to monitor the movements of 10,000 people in the city.
About 250,000 owners of Bluetooth devices, mostly mobile phones, have been spotted by Cityware scanners worldwide.

Bluetooth tracking technology is already being used to aim advertisements at people, for example as they walk past shops or billboards.

Bluetoothtracking.org, a website based in the Netherlands, is using the same technology to publish live data about people's movements across the town of Apeldoorn. The facility allows people to search the whereabouts of friends and associates without them knowing about it.

Some scientists using the technology describe a future scenario in which homes and cars adapt services to suit their owners, automatically dimming lights, preparing food and selecting preferred television channels.

I like Bluetooth as it makes my life convinient and also because one of our initial projects has been developing of complete Bluetooth marketing solution for a media company. So yes, maybe the next time you go to a shopping mall and get some advertised pumped on your handset using bluetooth then you can blame my company.

Ps: There is another article on Guardian by Dr Vassilis Kostakos from Bath University, defending his team. See here.

Monday, 21 July 2008

SDWN: Beyond Femtocells

Missed this one earlier from Fierce Broadband Wireless:

Femtocells have little ability to become self-organized or perform network management functions. WiMAX and LTE, on the other hand, are based on highly adaptive OFDMA air interfaces and IP communications that enable architecting of self-configured and distributed networks. They become part of the broader unified communications industry movement toward smart, distributed networking that is augmented by distributed storage and application servers. The largest opportunities for WiMAX are Smart Distributed WBB Networks, SDWN, and Purpose Use of Multiple Spectrum bands (PUMS).

The SDWN wireless interface layer is based on scalable OFDMA, adaptive modulation and power control methods that enable the network to adapt to a variety of channel bandwidths, range, multi-path environments, and attenuating signal conditions and usage.

The same factors that are now driving intelligent wired networks are amplified by the nature of wireless: limited available spectrum. MIMO- beam forming, smart antenna and smart power regulation built into remote and mobile stations can achieve very high localized performance while working as an adaptive layer within the managed network.

The term ‘WiMAXmesh' is used by some companies to describe SDWN functionality for multi-hop relay network capabilities now being implemented into WiMAX integrated circuits and network devices. Currently, WiMAXmesh can include on-board or local memory and storage, support for multiple external network interfaces and optimized network routing capabilities.

SDWN is highly motivated by the need to deliver cost effective networks able to respond to high bandwidth demands from both enterprise and consumer markets. The need to be integrated as part of enterprise level networks compels development of self-configuring, self-organizing WBB networks. The growing demand for personal broadband, including social networking and video media, will propel the pace of SDWN developments.

We believe that SDWN will develop over the next 10 years to become two to four times larger than the conventional centralized wireless broadband network market.

Key stake holders in SDWN development include most major companies involved in WiMAX and 3G-LTE including:

  • Alcatel-Lucent: A leading developer of co-MIMO, MU-MIMO technologies
  • Alvarion: An early implementer of distributed network capabilities
  • Cisco: We think that Cisco intends to become the leader in SDWN for both WiMAX and LTE. Products may not appear for up to two years.
  • Intel: Offers distributed processor architectures and enabling IP.
  • Nortel: An early leader in MIMO-OFDM and is continuing development toward SDWN
  • Motorola: The company is not as visible but has developed corresponding IP
  • Ericsson: Has recently entered submittals to 802.16 that correspond to work in LTE.
  • Huawei: A rising developer in SDWN technologies.
  • Numerous efforts are underway among WiMAX, LTE and multi-mode chip and smaller equipment suppliers. picoChip and DesignArt are noticeable examples.

Keywords:

  • WBB - Wireless Broadband
  • WBBN - WBB Networks
  • SDWN - Smart Distributed WBB Networks
  • PUMS - Purpose Use of Multiple Spectrum bands

Sunday, 20 July 2008

We are becoming a bunch of 'Techno Time-wasters'

This one is in todays Observer:

Time-wasting is not just an irritating habit. It is an affliction that ruins millions of lives and often requires therapy and other treatment for sufferers, psychologists have warned. According to new research, one person in five now suffers from the problem so badly that their careers, relationships and health are threatened. Many researchers blame computers and mobile phones for providing too many distractions for people.

'The subject is seen as joke,' said Professor Joseph Ferrari of DePaul University in Chicago. 'But the social and economic implications are huge. These people need therapy. They need to change the way they act and think.' Ferrari says that chronic procrastination is now so serious a condition it needs to be recognised by clinicians. In a study to be published later this year, he estimates that 15 to 20 per cent of people are chronic procrastinators
He has devised a questionnaire to help diagnose the condition, which he says is 'much more common than depression or common phobias'. Procrastination also has knock-on effects - it encourages depression, lowers self-esteem, causes insomnia, and indirectly affects health by discouraging visits to the dentist or doctor. Sufferers are also more likely to have accidents at home involving unmended appliances.

Cognitive psychologist Professor John Maule, of Leeds University's business school, agreed that a significant proportion of the population were prone to procrastination, and argued that mood changes - particularly depression - might be to blame.

Research by Professor Piers Steel from Calgary University indicates that the incidence of chronic procrastination has risen dramatically in recent decades, from one person in 20 to one in four, as new technology has come to dominate our lives. Even the beeps notifying the arrival of email are said to be causing a 0.5 per cent drop in gross domestic product in the United States, costing the economy $70bn a year.

Ferrari, however, is less convinced that new technology is to blame for time-wasting. 'People have wasted time for centuries,' he said. 'Lots of people, particularly people who often have to work under time constraints, put work off because they kid themselves that they work best when under pressure, when there's a deadline.

'Studies have shown this isn't true. They're conveniently forgetting the times when it all went horribly wrong - and selectively remembering the odd occasion when things went well under severe time pressure.'

Once, humans probably did have stronger excuses for delaying chores that didn't need immediate attention, say brain scientists such as Alan Sanfey at Arizona University, whose work has shed light on the evolutionary origins of procrastination.

It appears that the brain is divided into two parts. One triggers 'automatic responses' which take precedence over everything else - such as fleeing sabre-toothed tigers. The other governs 'deliberate responses' - writing that report due next week or booking a visit to the optician. Evolution has dictated that the former take precedence. Today there aren't any sabre-toothed tigers, but we still put things off.

Saturday, 19 July 2008

LTE and WiMax Harmonization

Everytime I decide to move away with the LTE and WiMax subject I just find something new to tell you guys. Recently I have found that some more debate is emerging from the LTE and WiMax camps regarding the harmonization between them.
As I said from the very beginning, in my opinion the harmonization of WiMAX and LTE makes good sense for the development of the industry. There is enough evidence that the two camps are interestedand participants from both the WiMAX and LTE camp and IEEE and ETSI 3GPP standards organizations have recognized the need to collaborate on development of communications.
You might remember from my previous blogs that outgoing CEO of Vodafone, Arun Sarin was one of the first to raise the issue openly of the two camps having a future together. Vodafone is among operators that have called for the merging of WiMAX and LTE because this will reduce conflicts and costs for the industry. The long-term trends in technology, regulation, ecosystem consolidation and globalization contribute to the rationale that wireless systems should strive to achieve common air interfaces where feasible. The primary obstacle to achieving harmonization of WiMAX and LTE is simply the commercial self-interests that prevent a common push forward.
Intel CEO Paul Otellini and Sean Maloney, head of Intel's sales and marketing, have called for harmonization between WiMAX and LTE, pointing out the goals of unified broadband communications and common use of technologies. But everything which is coming out of Intel in terms of two technologies, it clearly suggests that Intel will eventually provide combined support regardless of whether the standards groups achieve official harmonization or not. I am sure that Intel will provide a multi-mode WiMAX plus LTE chipset. Maloney came close to saying this but he preferred to say this
"We don't have any plans to do that yet; it would certainly be a nice long term goal."
I have no doubt that harmonization has become a hot topic because of heightened competition between WiMAX and LTE for a role in molding development of the next generation of wireless, 4G. While I do not think the current stage of development of WiMAX or LTE qualifies as 4G, both systems are frameworks for evolution to 4G.
There are several factors within wireless developments to compel harmonization. Following are some of them
-Pursuit of IMT-Advanced as the path to 4G
-Both existing 3G, ‘fixed' and new spectrum will be consolidated
-Multiple scale and application support
-Common SDR (Software Defined Radio) base stations
-Common Integrated Circuits
-Use of 80 percent to 90 percent common technologies
-Globalization of R&D
-Need for reduced cost for embedded applications & digital divide
-Harmonization of wireless standards is a stated goal of 3GPP
-Common ‘modular concept' for harmonization across systems

If we take a ‘30,000 foot perspective' at the evolution of communications, it becomes clear that arriving at common air interfaces is now not only feasible but also a desirable result. Leading wireless suppliers have consolidated in order to leverage content, services and applications across networks. Technology used in WiMAX and LTE are converging because both camps have come to similar conclusions on the technologies needed to form the next-generation evolutionary framework. In brief, the framework includes OFDMA, MIMO and Adaptive Antenna Systems (AAS) smart antenna technologies, and IP-based adaptive network architecture. The few significant differences between WiMAX and LTE are surmountable and can fit within the capabilities of increasingly adaptive radio techniques and smart IP-based network developments.
Further, societal demands for digital inclusion, a growing need for education, enterprise and government communications, harnessing of communications as an alternative to travel, and better use of spectrum resources compels a unified approach to wireless.
While all these talks of harmonization continue there are still some in the industry who favors one over another. This was evident when recently Sprint announced that it’s withdrawing from the Next Generation Mobile Networks (NGMN) Alliance, a group of global mobile operators that banded together last year to push for a common vision for networks and technologies beyond 3G. The operator was a founding member of the NGMN. Sprint said it ended its relationship with the NGMN Alliance after the group chose to endorse LTE (Long Term Evolution) for 4G. Sprint spokesman John Polivka said the NGMN was supposed to endorse the co-existence of various technologies without favoring one over another. In fact, he said, technology neutrality was a key tenet of the NGMN to make sure it didn't duplicate the work being done in existing standards bodies.
"Sprint was disappointed that NGMN shifted from its original technology-neutral stance. We respectfully withdrew our membership from the organization due to the change in direction," he said. "We are enthusiastically continuing with our plans to work with our burgeoning ecosystem and launch a WiMAX network in select U.S. cities beginning in the third quarter with expansion throughout 2009 and beyond."
Founding members of the NGMN Alliance include China Mobile, NTT DoCoMo, Vodafone, Orange, KPN and T-Mobile, all of whom back LTE. A quick look at the list of the 18 operator members on the NGMN Alliance website shows the majority of the operators come from the WCDMA community, whose 4G path is LTE.
Another evidence of favoring one over the other occurred when in-flight communications provider Aircell announced that the future of its mobile broadband network will be based on LTE (Long Term Evolution).
Today, the company's Gogo service uses CDMA 1xEV-DO Rev. A technology, which enables the company to offer its air-to-ground data service at a data rate of more than 12 Mbps peak to Gogo-equipped aircraft. By the end of 2009, further advances to EV-DO will enable Aircell to deliver a raw data rate of up to 22.7 Mbps to aircraft. And by the start of 2011, Aircell expects to deploy its 4G LTE network, which will enable a throughput of up to 300 Mbps to aircraft.
The company says LTE will enable in-flight services such as hi-definition and interactive television as well as multi-player gaming. Aircell said it also chose LTE as a way to future-proof its air-to-ground technology. Airlines will also benefit from LTE because the technology will allow them to enhance their operations by offering applications such as high-resolution weather to the cockpit, the company said.
The company's customers so far include Virgin America and American Airlines

Ron Resnick, president of the WiMAX Forum, has said that the harmonization between WiMAX and LTE is "really up to the operators if that's what they want to do." That is the deciding factor that will determine to what extent WiMAX and LTE harmonize within the standards groups. Make no mistake, the technologies, ICs, devices, and systems are in the process of converging. Whether this occurs harmoniously or with excess rancor is up to the industry.

Thursday, 17 July 2008

HSUPA is here

T-Mobile recently launched HSUPA network here in UK:

T-Mobile said, in certain areas, upload speeds will be five times faster than previously. It claims upload speeds of up to 1.4 Mbps. T-Mobile UK chief executive Jim Hyde said: "Mobile broadband has come of age. Today, 25 per cent of new contract customers are signing up and we expect to quadruple our user base in 2008.

"We knew mobile broadband would burst on to the scene and our continued investment in new technology is paying dividends for customers seeking a fast, consistent service which offers great value."

T-Mobile has also upgraded its HSDPA network, it said. It now boasts download speeds of up to 7.2Mbps within the M25.

Meanwhile, T-Mobile Germany has annoucned the completion of the HSPA upgrade to it's 3G network, meaning that customers can now download (HSDPA) at 7.2Mbps. The plan is that the upload speed (HSUPA) will be boosted to 2Mbps by the end of the year.

In other news, AT&T in USA plans for 2008 include the completion of the nation's first High Speed Uplink Packet Access (HSUPA)-enabled network by the middle of the year. The AT&T 3G network now delivers typical downlink speeds ranging between 700 Kbps (kilobits per second) and 1.7 Mbps (megabits per second), and it will now offer faster uplink speeds ranging between 500 Kbps and 1.2 Mbps. The faster uplink speeds allow AT&T's HSUPA-enabled laptop users to quickly send large files and take full advantage of the latest Internet and business applications.

An article in TelecomTV claims that Mobile Social Networking may be the killer application for the promised HSUPA:

This is the year for HSUPA, or High-Speed Uplink Packet Access, according to leading provider of the enabling technology, Qualcomm. HSUPA is the companion standard to HSDPA (the high speed downlink standard) and enables 3G users to upload large files - especially still photos or videos - in seconds rather than minutes.

Qualcomm says that while HSUPA used to be allocated only to the high end chipsets (for use on high end phones) it's now being included as standard for chipsets aimed at 'mid range' devices and by the end of the year will appear as standard on low end phones as well.
Why the adoption spurt? Mobile social networking and user generated contents are the main reason. Where many traditional data applications, such as receiving email, web browsing, and music and video downloading are overwhelmingly asymmetric (far more data coming down than going up) the coming mobile social networking wave looks likely to demand huge amounts of uplink capacity as users begin to use the features of their new upscale phones in earnest. High resolution multi-megapixel cameras mean big, chunky picture files; easy video capture means even larger video files; and new applications involving pictures and location, via GPS, require high quality, reliable connectivity back to the controlling server.


According to Qualcomm, mobile social networking will finally and resoundingly answer the question: Why do we need 3G?

We'll need it because the evidence shows that users are interested in taking social networking out of the confines of the tethered PC, and putting it on the road via their mobiles where it can blend with and enhance real, physical, non-virtual social networking: the sort which involves real people moving about and doing things in real places.

So users are fast moving beyond SMS and towards applications and services which will enable them to really share their activities at, say, live events.

So let HSUPA roll and let the fun begin.

Wednesday, 16 July 2008

Free TD-SCDMA phones with Mobile TV


China Mobile, the nation's largest mobile carrier, is to purchase around 40,000 TD-SCDMA mobile television phones tailored for China Mobile Multimedia Broadcasting (CMMB), Chinese telecoms equipment provider ZTE Corporation disclosed on July 8.

A handful of telecoms terminal providers including ZTE and Qualcomm Incorporated are preparing for the purchase. These mobile phones are scheduled to be offered to friendly users during the 2008 Beijing Olympic Games in August. Their wider usage is expected to come after the Olympics.
The Chinese telecoms authority has approved the market access of CMMB mobile television phones in the country. In fact, China Mobile is busying itself in furthering the mobile television phone technology - TD-Multimedia Broadcast Multicast Service (MBMS), and it plans to widely promote TD-MBMS mobile television phones after CMMB ones.

The State Administration of Radio Film and Television of China (SARFT) is designed to start commercial CMMB service in 37 capital cities across the country before the Olympics. So far, close to 30 cities have finished building the networks.


See Also:

Momentum Building for UMTS 900MHz


According to a recent paper published by GSA, momentum is building for introducing UMTS 900 i.e. WCDMA-HSPA systems in 900 MHz band, used today by GSM/EDGE networks, to help operators to extend voice, data and mobile broadband services coverage by leveraging the advantages of lower frequencies. UMTS 900 is on the roadmap of several manufacturers. Three
commercial UMTS 900 systems have launched, and 20 user devices have been announced by 6 manufacturers.

I have blogged on 900Mhz band in past. Technical specifications for WCDMA-HSDPA in the 900 MHz band (UMTS 900) were completed by 3GPP in December 2005. The 900 MHz band, denoted as Band Class VIII, is defined as paired bands in the range 880 to 915 MHz (uplink), and 925 to 960 MHz (downlink).

A Manx Telecom trial confirmed 30% improved inbuilding penetration compared to 2100 MHz, and 40% in deep indoor penetration. With HSDPA, throughput could increase by 10%, raising overall network capacity 5%. A key finding was the ability to hand over calls between base stations operating at different frequencies. The trial confirmed a GSM 900 operator could re-use sites for UMTS without having to redesign and re-deploy the network, thus significantly reducing operational costs.

Saturday, 12 July 2008

Will WiMax and LTE find happiness together?

So till now most of you must be coming slowly to the terms that there might be a possibility of LTE and WiMax working together. In the past blogs I stressed this point and also tried to convey some of the common grounds emerging for LTE and WiMax to work together. There is no doubt that the two technologies still struggle to find happiness together on a common platform.

From a software-defined radio (SDR) perspective, the opportunity for LTE and WiMax to seek a settlement is even more enticing. Flexibility, gate reuse and programmability seem to be the answers to the WiMax-LTE multimode challenge--and that might spell SDR

In todays advanced technology there are many multimode solution for SDR.

So will WiMax and LTE find happiness in Multimode SDR?

While it is true that Multimode solution via SDR has a well-deserved reputation for being expensive and overhyped, it is just as true that telecom chip designers are already adopting SDR techniques. They need to, simply to accommodate changes to ever-evolving standards.
The classic definition of SDR is having arrays of general-purpose processors running virtually all functions in software. But to achieve this is very time consuming and expensive as well. The approach of running all the functions of processor in a software can be expensive and may not be able to hit the price/performance targets of high-data-rate technologies such as WiMax and LTE.

Bit then we knows that the chip technology has never been any better than what it is today. Today’s innovative approaches for significant high standard of hardware architecture can make things simpler and can pave a path for SDR.

Such architectures are very oftern presented in the telecoms world on a regular basis and one such early entry is from Wavesat, which has a long history of designing OFDMA chips. The company has inked agreements with Compal Communications, a mobile-products ODM, to develop mobile WiMax products, and with Willcom, a Japanese telecom company, to develop XG-PHS broadband wireless products using Wavesat's Odyssey 8500 chip set. (http://www.eetimes.com/news/latest/showArticle.jhtml?articleID=208403496&pgno=3)

Wavesat presented the above chipset to both the LTE and WiMax camps. According to WaveSat the chip set is, in reality, a 4G platform that can implement any OFDM-based technology and thus can carry both WiMax and LTE together on it’s shoulders. Odyssey 8500 based on eight DSP cores is one such chipset.

But Wavesat is not the only company in the race of taking efforts towards SDR and hence finding a common solution for LTE and WiMax. Coresonic AB also has a multimode platform based on a new architecture: single instruction stream, multiple tasks. According the Coresonic AB CEO Rich Clucas SIMT can achieve the performance of very long instruction word architecture, but with lower control overhead and much lower program and memory usage.

Most of the big guns in the industry ahs acknowledged that Multimode baseband solutions for LTE and WiMax are challenging, but designing the front-end chip is truly daunting for several reasons, not the least of which is the wide spectrum covered by the two standards--about 4 GHz. LTE would likely support the 900-MHz to 1,900-MHz bands. WiMax has had to scramble to find available spectrum and, depending on region, may operate from 2.3 GHz to 3.5 GHz.
BitWave Semiconductor's programmable RF transceiver promises a way through the multimode thicket. Prototypes of BitWave's Softransceiver RFIC are already in the hands of selected ODMs Handsets and femtocells that incorporate the technology should launch next year. BitWave's technology digitally tunes passive circuit elements to make the analog functions such as LNAs, filters and mixers programmable.

With these new technologies in play, a little harmonization will go a long way. Everybody in the industry knows one thing very well that LTE is still very much in its development stage, Nor is WiMax standing still. Meanwhile the 802.16m task group is working to complete improvements that will make it look a lot like cellular, with such things as hand-offs. So even though there is air of some peace and vibes of togetherness between the two camps they are still looking to outdo the each other. Both LTE and WiMax camps are burning the midnight oil to achieve the perfect solution and if possible go alone.
WiMax camp knows very well that their technology is a proven one and is at a very advanced stage. They know very well that they can go places in the two to three years, the time it will take to even bring the LTE standard to commercial viability.
There is no doubt that LTE camp is worried that WiMax might chew up traditional cell market share by the time LTE becomes available commercially. In my view there is no doubt LTE and WiMax will merge down the road, but I think it will be the LTE folks doing the adapting. WiMax is here and will dominate. It is already dominating despite the puff fantasies of media reports to the contrary.

Advanced 3GPP Interference Aware Receivers

Receiver structures in UEs and Node-Bs are constantly being improved as products evolve and more complex features are added to HSPA. The result is improved system performance and higher user data bit rates. This trend is reflected in constantly changing UE receiver requirements in 3GPP. In 2006, 3GPP has studied further improved minimum performance requirements for UMTS/HSDPA UEs. These enhanced performance requirements are release-independent (i.e. apply also to a Rel-6 terminal with advanced receivers).


Interference aware receivers, referred to as type 2i and type 3i, were defined as extensions of the existing type 2 and type 3 receivers, respectively. The basic receiver structure is that of an LMMSE sub-chip level equalizer which takes into account not only the channel response matrix of the serving cell, but also the channel response matrices of the most significant interfering cells. HSDPA throughput estimates were developed using link level simulations, which include the other-cell interference model plus Orthogonal Carrier Noise Simulator (OCNS) models for the serving and interfering cells based on the two network scenarios considered.

This type of receiver attempts to cancel the interference that arises from users operating outside the serving cell, which is also referred to as other-cell interference. Interference models/profiles were developed for this other-cell interference in terms of the number of interfering Node Bs to consider, and their powers relative to the total other cell interference power, the latter ratios referred to as Dominant Interferer Proportion (DIP) ratios. For the purposes of this study item it was determined that five interfering Node Bs should be taken into account in the interference models. DIP ratios were defined based on three criteria: median values of the corresponding cumulative density functions, weighted average throughput gain, and field data. Of these criteria, the one based on the ‘weighted average’ was felt to offer a compromise between the conservative, median value criteria and the more optimistic field data criteria. In addition, two network scenarios were defined, one based solely on HSDPA traffic (HSDPA-only), and the other based on a mixture of HSDPA and Rel-99 voice traffic (HSDPA+R99).

HSDPA throughput estimates were then developed using link level simulations, which included the othercell interference models plus OCNS models for the serving and interfering cells based on the two network scenarios considered. The two-branch reference receiver, referred to as a type 3i receiver, was found to offer significant gains in throughput primarily at or near the cell edge. Link level results were developed for a wide range of operating conditions including such factors as transport format, network scenario, modulation, and channel model. For example, the gains for the DIP ratios based on the weighted average ranged from a factor of 1.2 to 2.05 for QPSK H-SET6 PB3, and from 1.2 to 3.02 for VA30 for network geometries of -3 and 0 dB. This complements the performance of existing two-branch equalizers (type 3), which typically provide gain at high geometries, and thus, the combination of the two will lead to a much better user experience over the entire cell.

In addition, a system level study was conducted that indicated that a type 3i receiver provided gains in coverage ranging from 20-55% for mildly dispersive channels, and 25-35% for heavily dispersive channels, the exact value of which depends upon user location. A second system level study divided the users into two different groups depending on their DCH handover states, where the first group collected users in soft handover (between cells), and the second group collected users in softer handover (between sectors of the same cell). The results of this second study indicate that the Type 3i receiver will provide benefits for users in these two groups, increasing their throughput by slightly over 20%. With regards to implementation issues, it was felt that the type 3i receiver is based upon known and mature signal processing techniques, and thus, the complexity is minimized. With two-branch, equalizer-based receivers already available in today’s marketplace, it appears quite doable to develop a two-branch equalizer with interference cancellation/mitigation capabilities. Given all of the above, 3GPP concluded that two-branch interference cancellation receivers are feasible for HSDPA, and a work item has been created to standardize the performance requirements with type 3i receiver.

More on this topic is available in the following:
  • 3GPP TR 25.963 V7.0.0: Feasibility study on interference cancellation for UTRA FDD User Equipment (UE)
  • Signal Processing for Wireless Communications By Joseph Boccuzzi
  • Simulation results can also be obtained from reports here.

Qualcomm to make Femto-Intelligent Handsets

The last time I read about Qualcomm bying stake in Femtocell maker Ip.Access, I overlooked it but now the rumors are that they want to be the leaders in Femto-Intelligent handsets. This fits well with Femto-optimised handsets plan that I blogged about.

Ovum had interesting analysis on the original news:

It's easy to see, though, how femtocells fit into Qualcomm's vision of the future of the wireless world. It's not too much of an exaggeration to say the company believes that the WCDMA radio technology is so good that no other is needed; curiously, ip.access's other industry investors, including Cisco and Motorola, are much more closely associated with the opposite position. Some years ago Qualcomm engaged in a sustained rubbishing of WiFi as a public access technology, and more recently it has given WiMAX the same treatment. Femtocells could be a route towards using WCDMA in home and other internal networking.

The reality may be more prosaic. According to Qualcomm Ventures' self-description, its “aim is to support Qualcomm's mission of enabling and fostering 3G (WCDMA) and wireless Internet markets through strategic investments in privately owned startup ventures.” With femtocells at least a plausible runner in the medium term in the future development of public mobile networks, not investing anywhere in the technology might almost be deemed remiss. In Qualcomm's own words, both it and ip.access “have developed key intellectual property for femtocells, share the same vision for femtocells, and can work together to make the most effective use of these ideas for the benefit of the whole femtocell industry.”

From ip.access's perspective, the deal is somewhat more straightforward. It believes that Qualcomm is buying in because of its technological excellence and 'traction' with operators - it claims involvement in a number of femtocell trials with major MNOs, though none of these has been publicly disclosed.

For ip.access, the money Qualcomm is bringing is less interesting than the relationships and influence - especially with standards organisations - that it adds. Privately held, the company already lists Cisco, Intel Capital, ADC and Motorola Ventures among its owners. Neither party is disclosing the extent of Qualcomm's investment, or whether it will have any significant impact on the balance of shareholdings.

We are still mildly sceptical about the femtocell business case; even though ip.access provides some interesting data on the impact that domestic femtocells can have on the capacity requirements for the macro network. But it's clear that Qualcomm's decision to buy into ip.access makes the proposition rather more credible.

Wednesday, 9 July 2008

Updated Paper on 3GPP Rel 7 and Rel 8 from 3G Americas

3G Americas, a wireless industry group supporting the GSM family of technologies in the Americas, has provided updates to its popular white paper titled UMTS Evolution from 3GPP Release 7 to Release 8: HSPA and SAE/LTE that explains the leading evolutionary roadmap for the GSM family of technologies to 3G and beyond. Globally, the demand for wireless data services is driving the growth of 3G UMTS/HSPA technology with more than 200 commercial HSDPA networks today and subscriptions to UMTS/HSPA estimated at over 236 million by Informa Telecoms and Media. With more than 3.1 billion subscriptions for the GSM family of technologies worldwide today, the potential for third generation HSPA technology is forecast to reach 1.39 billion subscriptions by year end 2012 and 1.8 billion by year end 2013 according to Informa.

UMTS Evolution from 3GPP Release 7 to Release 8: HSPA and SAE/LTE offers a further review of 3GPP Release-7 (Rel-7) upon its completion in the technology standardization process and an introduction to the improved features of 3GPP Release 8 (Rel-8). The paper explores the growing demands for wireless data and successes for a variety of wireless applications, the increasing Average Revenue per User (ARPU) for wireless services by operators worldwide, recent developments in 3GPP technologies by several leading manufacturers, and 3GPP technology benefits and technical features.


Upon the finalization of the Rel-8 standard later this year, 3G Americas will publish a new white paper on the 3GPP standards that will include the completion of Rel-7 HSPA+ features, voice over HSPA, SAE/EPC (Evolved Packet Core) specification and Common IMS among other new developments and features. Since HSPA+ enhancements are fully backwards compatible with Rel-99/Rel-5/Rel-6, the upgrade to HSPA+ has been made smooth and evolutionary for GSM operators. Additionally, Rel-7 standardizes Evolved EDGE with continuing development in Rel-8 which will improve the user experience across all wireless data services by reducing latency and increasing data throughput and capacity. Finalization of the Rel-8 standard by the end of this year will further progress market interest in commercial deployment of LTE. Leading operators worldwide are announcing their plans to deploy LTE as early as 2010 with trials already occurring today.

The popular white paper UMTS Evolution from 3GPP Release 7 to Release 8: HSPA and SAE/LTE was written collaboratively by members of 3G Americas and is available for free download here.

Sunday, 6 July 2008

The case for Femto-optimised handsets

Dean Bubley from Disruptive wireless has come out with a report arguing for the need of Femto-aware handsets. The following is an extract from the report summary:

Already, femto proponents are talking up massmarket business models that go beyond simple indoor coverage and macro-network offload. They are talking about 10’s of millions of subscribers, and new “in-home” services for users, that exploit fast and cheap local mobile connectivity.

But this is based on the notion that people will use their cellphones differently when in range of femtos. There will be different applications and behaviour when people are at home – perhaps content backups, podcasts or even advertiser-sponsored TV programming. The mobile phone may need to linked to TV, PC, HiFi or other items of domestic technology.

This report argues that if the phone will be used differently, it needs to be designed differently as well. Standard phones can work with femtocells, but they are not optimised. The phone needs to be “aware” of the femtocell, ideally both in the radio and the application platform.

The report looks at all the various "layers" of a typical phone, and examines how the advent of femtocells will drive changes and optimisations:
  • Physical design & form-factor of the handset
  • Radio layer & protocol stack
  • Internal hardware - memory, power management etc
  • Handset operating system & connection manager
  • New femtocell-related applications & capabilities

The study includes forecasts for the overall femtocell market, and scenarios examining how the evolution of femto-cell aware handsets may evolve. It examines the value chain of the phone design & manufacturing industry, and discusses the role of component suppliers, OS specialists and industry bodies.

More Info here.

The following is from an article in Tech World:

The devices could do useful jobs such as handling large media files on phones, but these applications won't work well unless the phone has a reliable way of knowing whether it is on the femto or the "macro" network, said Dean Bubley of Disruptive Analysis. Unfortunately, vendors' efforts to make femtocells work seamlessly with all existing phones has resulted in a definition which makes the femto look exactly like a macrocell, to the handset.

"If femtos change user behavior you will need to change the handsets," said Bubley of Disruptive Analysis, who warns in a report that femto-aware handsets will be required.

Femto-aware handsets will be important after 2010, said Vedat Eyuboglu, chief technology officer at femto maker Airvana, which supplies silicon modules to Thomson, a maker of home gateways including BT's Home Hub.

However, Bubley warned that the actual phones might get forgotten, or take too long to develop: "The debate around femto-aware phones may get mired in discussions about interference management and 3GPP R8 tweaks to the interfaces involved," he said. "It takes two years to alter protocol stacks and hardware - we won't have femto-optimized phones until at least the end of 2010."

The handset issue could be addressed by industry body the Femto Forum, said Forum chair Simon Saunders, announcing the Forum's new relationship with the Next Generation Mobile Network Alliance (NGMNA), a body helping specify requirements for WiMax and LTE systems.

"As well as phones, femtocells will be used by devices including dongles and ultra-mobile PCs," said Saunders. "They do not have such long development cycles as mobile phones."

The NGMNA is developing recommendations for a cost-optimized indoor node, and for self-organizing networks, both of which can be met by femtocell designs that the Femto Forum will help develop. The two bodies will promote joint solutions and submit them to standards bodies.

Saturday, 5 July 2008

Mobile TV! Still no joy

Mobile TV is floundering in one of its bastion (Korea ... other one being Japan). The following is from a report in telecoms.com:

With mobile TV services in the flagship market of South Korea floundering and with few signs that operators anywhere else have found a successful formula for launching such services, most operator and vendor delegates at the recent CommunicAsia Summit in Singapore struggled to find enthusiasm for the fledgling industry.

Some operators and vendors say that mobile TV should be subscription-based, to offer a reliable revenue stream; others say an ad-supported model is the most viable option; and still others argue that a combined pay/advertising approach is the way forward.

Figures from South Korea seem to suggest that both pay-based and ad-supported models have critical weaknesses, which would also apply in other markets in the region. A lot more experimentation and creativity from operators might be required to find the right model.
Those promoting the idea of a pay-based service say that only by charging for content can a business model work. They say operators must team up with content firms to acquire premium content - most particularly sports - that people will be willing to pay a monthly fee to view or even pay for on a per-view basis.


But this line of thinking seems flawed, given that there is a limited amount of blue-chip content for which people will be prepared to pay, most notably live sports events - such as English Premier League soccer games - or highlights of them.

The problem is, of course, that content-rights holders have become adept at exacting a premium price for key sports rights, meaning that mobile TV operators would have to recoup their heavy capital investment by charging high subscription fees.

This is a problem, since the high churn rate experienced by TU Media in South Korea seems to suggest that mobile TV subscribers are extremely price-sensitive.

TU Media subscribers pay just KRW13,000 ($12.60) a month for the service but have been leaving in droves after their initial one-year contracts finish, forcing the firm to offer significantly reduced subscription rates to keep subscribers from deserting the service.

TU Media's experience suggests that mobile TV subscribers will be willing to pay only so much for services and that although blue-chip sports content has a crucial role to play, operators must find a way to acquire the content without paying excessive prices.

On the advertising side of the debate, many delegates at CommunicAsia argued that an ad-based strategy would work best for mobile TV platforms but that operators would have to be extremely creative in their approach.

There is no magic bullet that will provide a successful business model, but there seems to be a reasonable possibility that an attractive model can be built if operators can match the largely young and technology-friendly subscribers viewing mobile TV on their handsets with advertisers desperate to reach such a market.

Intriguingly, conference delegates also discussed the possibility that broadcast-type mobile TV services might never fully take off in the region and that Multimedia Broadcast Multicast Service (MBMS) video streaming over high-speed HSPA and future LTE networks would dominate the market.

The debate has strong proponents on both sides. Many vendors back an MBMS approach, saying that experience shows that broadcast-style services are not what users are demanding and that the more-narrowly targeted VOD-style content being offered on HSPA networks is already proving hugely popular.

The pro-MBMS argument also runs that with HSPA/LTE networks already in place and offering voice, data and video services, why go to the expense of deploying a terrestrial or satellite-based mobile TV network, especially with the expense involved in creating high-quality in-building reception?

Although this is a persuasive argument, it has shortfalls, most notably the fact that even LTE networks will still be point-to-point networks and will be unequipped to operate as point-to-multipoint services, which a full broadcast mobile TV service would require.
The broadcast-mobile-TV lobby argues strongly that the core strengths of broadcast-based networks cannot be replicated by even high-speed mobile networks, which would not be able to support the huge demand that's sure to arise for broadcasts of live sports and important news events.


In reality, the MBMS-vs.-broadcast-mobile-TV debate is spurious, given that both technologies are going to be on the market, and it will be users who determine which is the more successful.
At this early stage, it looks likely that subscribers and operators will use high-speed, quality video streaming for VOD-based "snacking" on content and that full broadcast mobile TV will be used for some live events, for which only a broadcast-style service can supply the quality of service required.


Korean Insight has an interesting section on Mobile TV (but no blogs on this topic for some time). A blog on this topic last year says a lot:

As TU Media started operations in mid 2005 it tried to acquire simultaneous re-transmission rights from broadcasters. This means that S-DMB viewers would be able to watch popular dramas and shows simultaneously with fixed TV. These contents are considered the most popular on both fixed and mobile TV. However, previously have broadcasters been reluctant to share these contents because they wanted to use it for their own T-DMB service. This is why S-DMB had to focus on other contents like sports and news. But the lack of “killer” contents from fixed TV hindered S-DMB development (as shown in the graphic above). Until today it had been able to acquire approximately 1.26 million subscribers. But according to TU Media they need approximately 2.5 million subscribers to be profitable.

But also T-DMB is struggling to build a profitable business. Despite more than seven million T-DMB devices in Korea the advertising revenues are marginal. Which partially is the result of very restrictive legislation on advertising but also broadcasters have failed to develop an attractive mobile advertising value proposition to make this channel more attractive for advertisers.

Consumers have embraced this new medium and it is very likely that broadcasters will take mobile TV more serious and endeavor to make mobile TV advertising more attractive for broadcasters. Until 2012 more than 20 million T-DMB devices are expected, so mobile TV has a future in Korea.

LTE And WiMax Together?

In my last blog I talked about LTE and WiMax finally finding a peace in each other and the early signs of the two having a future together. As I said before I have always believed that the two technologies as a basic are not very much different. I certainly support the notion that the industry can benefit a lot from the two working side by side.

But as always when I was discussing this with some of my friends in the industry they questioned about the similarity between the two technologies.

So how much similar or different they are?

Whenever the similarity between LTE and WiMax is discussed we conclude that the single most important similarity between LTE and WiMax is orthogonal frequency division multiplex (OFDM) signalling. Both technologies also employ Viterbi and turbo accelerators for forward error correction. From a chip designer's perspective, that makes the extensive reuse of gates highly likely if one had to support both schemes in the same chip or chip set. From a software-defined radio (SDR) perspective, the opportunity is even more enticing. Flexibility, gate reuse and programmability seem to be the answers to the WiMax-LTE multimode challenge and that might spell SDR.

So to start with I just concentrated on OFDMA and did some research to find out how much similar the two technologies are in terms of OFDMA or are they?

Most of the articles and discussion shows that LTE and WiMax may be two peas in an OFDM pod, but they are not twins. Here are three significant differences:

1. Both use orthogonal frequency division multiple access (OFDMA) in the downlink. But WiMax optimizes for maximum channel usage by processing all the information in a wide channel. LTE, on the other hand, organizes the available spectrum into smaller chunks.
WiMax pays a price for high channel utilization, however, because processing that much information might require a 1,000-point fast Fourier transform. LTE can get by with a 16-point FFT. This translates into higher power consumption, because it's difficult to design fixed-function WiMax hardware that is also efficient in LTE designs. An architecture that exploits the principles of SDR, however, could reconfigure its FFT function for better power efficiency.
2. LTE uses single-carrier frequency division multiple access (SC-FDMA) for uplink signaling, while WiMax sticks with OFDMA. A major problem with OFDM-based systems is their high peak-to-average power ratios. The average power spec cited in marketing presentations does not show the whole picture. Unfortunately, the system's power amplifier has to be designed to handle peak power--and the PA is the single-largest power consumer in a handset.
LTE opted for the SC-FDMA specifically to boost PA efficiency. "If you can improve the efficiency from 5 percent up to 50 percent simply by changing modulation schemes, then you save a lot of battery time," said Anders Nilsson, principal system architect at multimode specialist Coresonic AB. WiMax's OFDMA has a peak-average ratio of about 10 dB, while LTE's SC-FDMA's peak-average ratio is about 5 dB.
The difference also affects the baseband chip, Nilsson added, because of the need to support two modulation schemes in the uplink. Programmable solutions are flexible enough to reuse gates and keep power low in LTE mode.

Regarding the PAPR issue (Peak to Average Power Ratio), I found the following tutorial interesting
http://to.swang.googlepages.com/peaktoaveragepowerratioreduction

3. Although both the IEEE 802.13e standard and the evolving LTE standard support frequency division duplexing (FDD) and time division duplexing (TDD), WiMax implementations are predominantly TDD. LTE seems to be heading in the FDD direction because it is true full-duplex operation: Adjacent channels are used for uplink and downlink. LTE can therefore quote a better spec for downlink data rates, albeit at a cost of placing very severe latency requirements for forward error correction. The bottom line is that the WiMax radio is much simpler
These differences make designing a chip or chip set to support both standards more difficult, but they also have network infrastructure consequences that might be more easily resolved by harmonization instead of competition. Certainly, from the handset designer's perspective, there is no clear winner.
The battery life and power efficiency of the chip or chip set are critical to market success, said Fannie Mlinarsky, an independent consultant specializing in wireless testing and design. Power is a big issue for WiMax and LTE because megabit-per-second capability means running the DSP hard and making the chips more power hungry.

Thursday, 3 July 2008

Rumors: Femtocells being rolled out from this month

Sprint's indoor coverage-extending femtocell device, Airave, will be rolled out nationwide on July 15 (USA) according to early reports. Airave is a device which connects to any cable modem or DSL router with an open port, and generates a signal to which mobile phones can connect. Airave allows up to three simultaneous voice connections to be made within a 5,000 square foot coverage area.

Additionally, Airave comes with a 20-foot long antenna (cant be right) that must be stationed near a window so its onboard GPS receiver can connect. This is necessary for the device to function because the GPS determines if it is stationed within Sprint-licensed territory. If this device is used in an area that does not offer some degree of native Sprint coverage, it will not function.

This is a bold move from Sprint considering this another story from Unstrung titled, "Operators Feel Femto Frustration":

A lack of standards, unresolved technical issues, and unclear business cases are conspiring to push operator plans for commercial femtocell launches into next year. That’s the message from major mobile operators at the recent Femtocell Europe 2008 conference. While operators are still enticed by the potential for cost savings, capacity increases, and new service revenues that the mini home base stations promise, they gave a realistic account of their own plans for femtocells here, and they said they anticipate commercial deployments in the market some time in 2009 .

The lack of a definitive standard for femtocells is a sticking point for operators and has even caused some to postpone their vendor selections. SFR , for one, has delayed its femtocell RFQ (request for quotation) because the standards are not yet defined.

While equipment suppliers have taken a big step recently to agree on a framework for defining a femtocell standard -- thanks to vendor compromises and the Femto Forum Ltd. facilitating a consensus -- the hard work to hash out a standard at the 3GPP is just beginning.
T-Mobile International AG ’s head of RAN strategy, Zhongrong Liu, said the femtocell standardization process was hampered by “lack of resource or focus from big vendors,” and he urged them to send more delegates to the 3GPP working groups.

O2 (UK) Ltd. has found in recent femtocell tests that the devices were not hitting HSDPA data speeds. Chris Fenton, director of convergence policy at O2, said that the femtocells the operator tested recently got to just 700 kbit/s on the downlink. “There is some work to do to get us to the 3.6 Mbit/s and 7.2 Mbit/s” he said. “We’re testing early boxes, though -- I think it’s really close, so that’s OK.”

Operators admit that they are not yet certain of what the service proposition for home base stations should be or how they’ll make money from the devices. Some look to femtocells simply to improve indoor coverage, which could have a big effect on churn. AT&T’s Gordon Mansfield, director of radio access network planning, said that poor coverage is the number one cause of churn. “In the U.S. market, we’ve got these challenges,” he said.

Mansfield said that early femto deployments would be aimed at improving indoor coverage and that future deployments could be aimed at “integrating three screens in the home,” or, in other words, tying the mobile phone into consumers’ home networks.

Another article in Unstrung last month had an interview with Vodafone visionary on how Vodafone dreams of Metro Femto:

Femtocells could one day proliferate in metropolitan areas at bus stops, on lamp posts, or on buildings, if Vodafone Group plc's vision for a hotspot deployment of femto access points becomes reality. The giant mobile operator's head of new technologies and innovation, Kenny Graham, proposed taking the mini home base stations out of the home/office and onto the streets at the Femtocells Europe 2008 conference in London Wednesday morning. Graham (a.k.a. the Vodafone Visionary) reckons the same attributes that make femtocells ideal for deployment in homes and offices -– localized coverage, improved performance, self-configuration, self-optimization, and low cost -– can be of use outside, too. He dubbed this kind of deployment a “metrozone.”

Meanwhile operators are working hard to make sure the cost of Femtocell hits rock bottom:

Telecoms operators are pushing to get the cost of a 3G femtocell in the home down to €40 – well below the current $99 (€63) target. "For the femtocell to be economically viable compared with the macrocells, it has to be less than €40 in the total cost of ownership per access point," said Thierry Berthouloux, head of network evolution at French mobile phone operator SFR, speaking at the European Femtocell conference. "It is not €100, that is far to expensive, and that is really the challenge," said Berthouloux.

Tuesday, 1 July 2008

NFC: Near-Field Communication


Saw this posted on Forum Oxford. Very good introductory article on NFC:

Near-field Communication (NFC) is characterized as a very short-range radio communication technology with a lot of potential, especially when applied to mobile handsets. Imagine yourself using your cellphone to interact with posters, magazines, and even with products while at the store, and with such interaction initiating a request or search for related information in real-time. Other usages of NFC include the electronic wallet to make payments using your handset, the same way you do with your credit card. With NFC all this is possible. But NFC is still a young technology. That said, NFC-enabled handsets are being introduced into the market, and deployments and pilots around the world are occurring.

Near-field Communication or NFC is a standard defined by the NFC Forum, a global consortium of hardware, software/application, credit card companies, banking, network-providers, and others who are interested in the advancement and standardization of this promising technology.

NFC is a short-range radio technology that operates on the 13.56 MHz frequency, with data transfers of up to 424 kilobits per second. NFC communication is triggered when two NFC-compatible devices are brought within close proximity, around four centimeters. Because the transmission range is so short, NFC-based transactions are inherently secure; more on this shortly.

When compared to the other short-range radio technologies, NFC is extremely short ranged and what I call people-centric. Some of the other short-range communication technologies have similar characteristics, for example RFID, while others are completely different yet complimentary to NFC; for example Bluetooth and Infrared. A good scenario of such compliment is the combination of NFC and Bluetooth, where NFC is used for pairing (authenticating) a Bluetooth session used for the transfer of data.

Complete Article at Sun Developer Network.
More about NFC at NFC Forum homepage.