Wednesday, 27 June 2007

LDPC Codes History

The history of coding starts with the seminal work of Claude Shannon on the mathematical theory of communication in 1948. He demonstrated that errors induced by a noisy channel can be reduced to any desired level as long as the information rate is less than the capacity of the channel. The theoretical maximum information transfer rate is called Shannon limit.

In 1962, Gallager proposed a low-density parity-check code in his doctoral dissertation. LDPC codes are defined by a sparse parity-check matrix. They provided near-capacity performance but difficult implementation. Also, the concatenated RS and convolutional codes were considered perfectly suitable for error control coding. Thus, his remarkable thesis was forgotten by coding researchers for almost 20 years. In 1981, Tanner generalized LDPC codes and created a bipartite graph used to represent those codes. However, it was still ignored by coding theorists.

LDPC codes were noticed again by some researchers in the mid-1990’s. They began to investigate codes on graph and iterative decoding. Markey and other researchers discovered the advantage between linear block codes which generated by sparse matrix and iterative decoding based on belief propagation. And by that time the decoding complexity looked achievable. Since that time, a lot of papers have been published and LDPC has become popular so far.

Monday, 25 June 2007

WiMax to rack up '54 million subscribers by 2012'

[Quote from]

WiMax is set to rack up 54 million subscribers worldwide within five years - but only if it can capitalise on emerging markets.

A report from consultancy Senza Fili Consulting - WiMax: Ambitions and Reality - predicts the combined total of fixed, mobile and fixed, and mobile WiMax will amount to 54 million users by 2012.

According to the consultancy the best prospects for the tech are tied to the rollout of mobile services - and it predicts that by 2012 61 per cent of subscribers will use WiMax for mobile access.

Monica Paolini, author of the report, said the recent inclusion of WiMax as an IMT-2000 (International Mobile Telecommunications 2000) technology will enable mobile operators to deploy it more widely.

But the mobile market will take longer than fixed to grow because most mobile operators do not yet need a data-only wireless network to complement their 3G networks.

While 3G and wi-fi have managed to co-exist up to now the future impact of WiMax on mobile operators' 3G networks is uncertain.

But according to the report in the next five years WiMax will become a mature technology for mobile broadband access.

Thursday, 7 June 2007

10 things your phone will do in 10 years

Hi, Rick, Goker, Jerry, Carl, I am so feeling a little embarrassed for being so long in the member list but never willing to post or even comment on a posted article. No excuse, my bad..

As I am now working in the Mobile Device Software Dept. in a mobile phone manufacturing company, I got some deeper experience and thinking about this industry. I received a really good article from company internal spread mail, titled as "10 things your phone will do in 10 years", I would like to share it with all of you.

The cell phone used to be mainly about making phone calls, but those days are long gone.

The past decade has seen the device evolve into the Swiss Army Knife of consumer electronics. Not only can you take pictures and video with your phone, you can use it to send e-mails, chat on instant messengers, listen to music, get directions, and even watch television.
The technology has come a long way since the days of brick-shaped analog phones that barely fit in a purse, let alone a pocket. Two years ago, experts predicted that there would be 3 billion cell phone subscribers worldwide by 2010. Now it looks as if we'll pass the 3 billion mark by the end of this year.
As wireless-service operators continue to deploy third-generation, or 3G, networks, which support high-bandwidth applications such as video and Internet access, this phenomenal growth is likely to continue. But a big question for consumers is: what will these phones do? CNET talked to industry experts and executives and spent some time gazing into a crystal ball to come up with the following list of 10 things the average cell phone user will be doing with his or her phone in the not-too-distant future.

1. No wallet? No problem
A new technology standard called "near-field communications," or NFC, will turn cell phones into credit or debit cards. A chip is embedded in a phone that allows you to make a payment by using a touch-sensitive interface or by bringing the phone within a few centimeters of an NFC reader. Your credit card account or bank account is charged accordingly.
Unlike RFID (radio frequency identification) technology, which also can be used to make wireless payments, NFC technology allows for two-way communication, making it more secure. For example, an NFC-enabled handset could demand that a password or personal identification number be entered to complete the transaction.
The NFC mobile-payment application is currently in trials in the United States, Germany, Finland, the Netherlands, and a few other countries. The technology is widely used in Japan, where people use their phones to pay for everything from sodas dispensed in vending machines to subway cards. Nokia announced the first fully integrated NFC phone, the Nokia 6131 NFC, at the Consumer Electronics Show in Las Vegas in January, and the company is currently testing the 6131 with AT&T's Cingular Wireless in New York City.
Experts also note that NFC technology can be used for more than just retail transactions. It can be used to get data from an NFC-equipped business card, or to download tickets or other data from an NFC-equipped kiosk or poster.

2. The World Wide Web in your pocket
The promise of the mobile Internet has yet to live up to its hype. Users have had disappointing experiences with HTML Web sites that render poorly on handsets, or they've been forced to use stripped-down wireless application protocol, or WAP, sites that don't provide the same richness that they have come to expect on the wired Web. But as more phones come equipped with full HTML browsers, cell phones will truly become just another device used to access the Internet.
Today many smart phones already provide full HTML browsers. Nokia's latest N-series and E-series phones, which run Opera browsers for the Symbian operating system, are among the most advanced.
In the future, these mobile HTML browsers will make their way onto even the most basic phones. Motorola recently announced it is adding an HTML browser to its popular Razr phones.
So what will full Internet browsing mean for users? For one thing, it could accelerate the growth of mobile social networking. In the last couple of years, social-networking sites such as MySpace and YouTube have become hits. Now people are extending those social networks to their cell phones. In December, ABI Research said that almost 50 million people used social-networking sites on their mobile phones. That number is expected to grow to 174 million by 2011.
Mobile operators such as AT&T and Helio have a special deal with MySpace, and Verizon Wireless has a special deal with YouTube. Mobile phones could allow people to more seamlessly connect their virtual presence with their physical presence. But Charles Golvin, an analyst with Forrester Research, predicts that this fact alone could mean that people will form smaller, more-private social networks with their mobile phones instead of simply using the phones as extensions of the social networks they created using their PCs on sites like MySpace.
"Do you really want everyone on MySpace to be able to track where you are?" he says. "Cell phones are such personal devices, and they go with us everywhere. I think people will be more inclined to communicate among smaller groups who they already know and socialize with."

3. Location, location, location
Due to a Federal Communications Commission mandate that requires operators to locate people when they dial 911 in an emergency, a large number of mobile phones sold in the United States already have integrated GPS (global positioning system) chips. While these chips are used by some mobile operators to pinpoint users' locations when they're in danger, they can also be used to support a variety of location-related services.
The most obvious service is turn-by-turn navigation, which provides directions simply by allowing users to type in a destination. Satellites then locate the GPS-enabled device and map the device's location to the destination. A map can then be generated on the user's screen, along with text-based directions. Some devices will also "read" the directions to the user.
Verizon Wireless and Sprint Nextel already offer navigation services. Verizon charges $9.99 a month for the service and Sprint is offering the service for free when customers buy certain data packages. Handset makers Nokia and Motorola also plan to offer navigation map services. In February at the 3GSM Wireless trade show in Barcelona, Nokia introduced the 6110 Navigator, the company's first navigation-enabled handset designed for the mass market.
But location services will soon go far beyond navigation. GPS technology will also be used to enhance local search engines, so that when you type in the word "pizza" you get a list of local pizza parlors, rather than a list of pizza-related Web sites.
Media conglomerate IAC/InterActiveCorp, which owns more than 60 Internet brands, said recently it will use GPS-enabled search on its mobile Web site to help consumers find friends, shops, and services based on their locations. The application will be available on Sprint's network. IAC plans to add the feature later to some of its other Web sites, such as Ticketmaster and
Mobile virtual network operators Boost, Helio, and Disney Mobile are already offering tracking services that allow people to keep tabs on their kids or find their friends. Many of these services are beginning to come to market now, but by 2010 they should offer better accuracy and will also reach more mainstream users.

4. Search goes mobile
Mobile search will become a standard feature on all handsets over the next three years. Most phones will likely have search built into their main screens, with a search icon prominently featured next to the time and the icons depicting battery and signal strength. Some phones will actually have a search button on the keypad or protruding from the case. In April, Alltel Wireless announced that it would preinstall JumpTap's mobile search button on LG Electronics' LGVX8600 devices.
Helio's new smart phone, the Ocean, has a search feature that allows you to slide out the keyboard, type a keyword, hit Enter and immediately get results from Google, Yahoo, and Wikipedia.
While the big guys--Google and Yahoo--will certainly have a presence on mobile devices, "white label" services, such as one available from JumpTap, will also be popular because they allow carriers to brand the service as their own.

5. TV on the go-go
Mobile TV in all its forms is expected to explode in the next few years. IMS Research forecasts that by 2011 there will be more than 30 million mobile TV subscribers in the United States. The firm also predicts that almost 70 million handsets capable of receiving mobile TV will be shipped in the U.S. in 2011.
Consumers will have access to a wide range of TV possibilities on their phones, from original and professionally produced content to repurposed clips to live broadcasts and user-generated clips.
The mobile handset will become an extension of TV and computer screens at home, allowing consumers to time- and place-shift viewing. Sling Media already offers mobile users the option of viewing programming available on their home TVs on their Windows Mobile devices using a wireless data connection.
Four major cable operators working with Sprint Nextel--Comcast, Time Warner, Cox Communications, and Advance/Newhouse Communications--are also expected to expand some video programming to cell phones. Today they offer features such as remote programming for DVRs.
Over the next three years, broadcast TV networks designed to provide service for mobile devices will also emerge on the scene. Qualcomm's MediaFlo has already signed deals with Verizon Wireless and AT&T, which will use MediaFlo broadcast technology to distribute live TV programming to mobile subscribers. Another broadcast technology, known as DVB-H, will likely find a strong following in Europe.
Experts believe there will be a spike in mobile TV usage in 2008 when the Summer Olympics in Beijing are scheduled to take place. Many operators around the world expect to have their mobile video services up and running to air the games.

6. Simplifed surfing
Ever notice how many clicks it takes to find the one thing you're looking for on your phone? It's worse than counting how many licks it takes to get to the center of a Tootsie Roll Pop. But handset makers and mobile operators are hard at work trying to make phones easier to navigate and simpler to use.
The upcoming iPhone from Apple is a perfect example of how user interfaces will be improved. Apple fans are confident that the company has come up with another slick and intuitive design, just as it did for the iPod.
One aspect of the iPhone's interface that has been publicized is its use of sensory technology to detect when the device is rotated. This allows the phone to automatically render pictures on the screen in portrait (vertical) or landscape (horizontal) format. That allows the user to determine which format is best for viewing whatever is on the screen, be it a Web page, video, or photo.
In the future, motion-sensing technology, similar to that used in the Nintendo Wii game console, will also allow people to navigate their cell phone menus or the mobile Internet with a flick of their wrists.
But motion sensing is just one piece of the puzzle. Operators such as Verizon Wireless are redesigning their content menus to reduce the number of clicks users must endure to find what they want. Ryan Hughes, vice president of digital media programming for Verizon Wireless, said he believes that user interfaces will be customizable so that users can decide for themselves which applications will be displayed on their phones most prominently.
Motorola is already offering a customizable interface on the Razr 2, which the company claims will make searching for contacts, accessing applications, and messaging much easier.

7. Brainier radios
Many phones today are equipped with dual radios that let subscribers roam on differently configured cellular networks throughout the world, but in the next few years handset makers will also embed Wi-Fi technology into phones, allowing customers to use the devices in any Wi-Fi network hot spot.
T-Mobile USA has been experimenting with such a service for the past several months in its hometown of Seattle. The HotSpot @Home service, which is expected to launch across the country this summer, uses UMA (unlicensed mobile access) technology to allow phones to seamlessly switch calls between a Wi-Fi connection and a cellular connection, depending on which is available and most cost-effective at any particular moment.
T-Mobile HotSpot @Home costs $20 a month on top of a regular cell phone plan, and it delivers unlimited "voice over Wi-Fi" calls from T-Mobile's more than 8,000 hot spots and through any Wi-Fi access point in a home that is connected to a broadband Internet service.
These dual-mode Wi-Fi and cellular phones will also make it possible for users to use voice over Internet Protocol services like Skype to avoid roaming charges when they are traveling internationally, for example. Skype is already available on PocketPCs and Windows Mobile smart phones.

8. Your very own cell tower
Does your cell phone get bad reception inside your house, but works just fine when you stand on your porch? Mobile operators may soon ask you to help them improve cellular coverage in your home or office with small Wi-Fi-like routers that boost cellular signals.
These routers create what are called femto cells, or small personal cellular sites. And they could help solve a major problem for cellular operators who have trouble covering less-populated regions or have difficulty reaching users indoors.
The femto cell router has a cellular antenna to boost the available cellular signals in a small area. The device is then attached to a broadband connection, and uses voice over IP technology to connect cellular phone calls to the mobile operator's network.
Because cell phones use licensed spectrum, the devices would be tied to a particular carrier's network just like a handset. If a consumer wanted to switch carriers, he'd have to get a new femto cell router.
While no carriers in the U.S. have said they plan to use femto cell technology, several companies are already developing products for it. 3Way Networks, based in the U.K., and Ericsson, based in Sweden, each introduced femto cell devices in February.

9. Picture perfect
One of the most dramatic changes in cell phone technology over the past decade has been the emergence of the camera phone. Today roughly 41 percent of American households own a camera phone. In fact, you'd be hard-pressed to buy a phone today that doesn't have a camera.
By 2010 more than 1 billion mobile phones in the world will ship with an embedded camera, up from the 589 million camera phones that are expected to be sold in 2007, according to market research firm Gartner.
There's little doubt that the technology will improve, with high-end phones easily supporting 8-megapixel cameras. The Nokia N95 already offers a 5-megapixel camera. William Plummer, Nokia's North America vice president of sales and channel management for multimedia, says that in a few years users will likely be able to manipulate their images directly on their handsets, just as they would on a high-end digital camera or PC.
Some camera phones will also let users stream live video to friends, family, co-workers, or anyone else with a video-capable phone. Motorola's Razr 2, due out this summer, will support this feature. And AT&T will offer two-way video sharing as a service later this summer using devices made by LG Electronics.
Phones of the future will also come with multiple cameras that will provide additional functionality, Forrester's Golvin predicts. While one camera may provide high-end imaging for sharing pictures and video, a second, lower-end camera could be used for things like capturing two-dimensional bar codes known as QR codes.
QR code-reading software on camera phones eliminates the need to type in contacts or URLs. In Japan, they're already widely used to store addresses and URLs on the pages of magazines, with the codes pegged to both editorial content and advertisements. The addition of QR codes to business cards is also becoming common, greatly simplifying the task of entering contact information into mobile-phone address books.

10. Mad for mobile music
There's no question that mobile music is hot and will continue to grow in popularity. Mobile phone users around the globe are expected to spend $32.2 billion on music for their handsets by 2010, up from $13.7 billion in 2007, according to Gartner.
This content category includes everything from basic ringtones, "real tones" (uncompressed, digital representations of analog signals), and ring-back tones to more sophisticated full-track downloads. Music in all its incarnations is the second-most popular mobile data service, behind short message service (SMS), in terms of use and revenue.
Over the next couple of years, full-song downloads will drive growth in this category. The entrance of big brands like Apple into the mobile phone market will likely push mobile music to the forefront.
Apple's iPhone, announced in January, has created a kind of hysteria that has not been seen before in the consumer electronics market. The device, which combines Apple's popular iPod music player with a mobile smart phone, will go on sale in late June and will be available exclusively on AT&T's network. Even though critics have already noted some downsides to the iPhone--namely that it will not be 3G capable--it has still managed to raise the bar in terms of what's expected from a music playing phone.
All the major handset manufacturers are poised to offer iPhone competitors. Sony Ericsson has the Walkman series. Motorola has its Rokr, Z8, and MotoQ phones. And Research In Motion, best known for phones that cater to business users, has the new BlackBerry 8300 Curve, which comes with stereo Bluetooth, a true 3.5mm headphone jack, and a microSD expansion slot. All of these phones could be strong competitors, if not iPhone killers.
So what will be new in mobile music by 2010?
Most likely it will be more of the same. The line between phones and music players will increasingly blur. And if network operators, device makers and music studios are smart, there will be easier and more cost-effective ways for people to download their favorite tunes onto their phones.
Verizon Wireless, Helio, and Sprint Nextel already offer over-the-air downloads. But many experts believe that, in order to compete, all major operators will have to offer this convenience. And issues surrounding digital rights management--the use of software that limits the use and transfer of copyright material, including music and video files--will also likely be worked out in the next few years to allow users an easy and legal way to port songs from one device to another.

Tuesday, 5 June 2007


Jajah is a VoIP (Voice over IP) provider, founded by Austrians Roman Scharf and Daniel Mattes in 2005.[1] The Jajah headquarters are located in Mountain View, CA, USA, and Luxembourg. Jajah maintains a development centre in Israel.
Jajah's primary service, Jajah Web, takes an approach called web-activated
telephony, using VoIP to connect traditional phones (landline or mobile). Calls are made without download or user-installed software, and in most cases at rates lower than those of traditional phone companies or even free of charge.

Jajah Web connects existing traditional
landline or mobile phones with calls that are set up via Jajah's Web site. Callers type in their own number and their desired destination number in a Web form. The Jajah service first rings the caller. After the caller picks up the phone the destination number is then dialled and the connection is established.
Jajah claims that their service works with any standard
web browser. It does not require a broadband connection, nor is it necessary to be online when using the service, but it is necessary to have internet access to originate the call.
Dial-up internet users without a second phone line must schedule their call to be placed a few minutes in the future in order to allow for the time required to disconnect from their ISP and free up the phone line.

Jajah Free Global Calling
Jajah launched a service offering free calls globally on
28th June 2006. The service is limited to specified geographic areas, and Jajah has also adopted a Fair Use Policy which limit the amount of free Jajah calls.
Calls between registered Jajah users are free of charge for landline and mobile calls within the USA, Canada, China, Singapore, Hong Kong, Thailand and apply also for landline calls to and within most European countries as well as Argentina, Australia, Israel, Japan, Malaysia, Mexico, New Zealand, Venezuela and Zambia.
A further limitation is that scheduled calls and conference calls cannot be free.
(From Wikipedia)

Friday, 1 June 2007

PAL region

The PAL region is a video game publication territory which covers Australia, New Zealand, and varying European countries. The majority of games designated as part of the region will not play on NTSC-U/C or NTSC-J region consoles because of regional lockout. While this is the most common occurrence, some Xbox and Xbox 360 games are region-free encoded, since Microsoft's policy is for publishers to decide. Nintendo handhelds are region-free, but their consoles are not.

Games ported to PAL have historically been known for having game speed and framerates inferior to their NTSC counterparts. Since the NTSC standard is 60 frames per second but PAL is 50 frames per second, games were typically slowed down by approximately 17.5% in order to avoid timing problems or unfeasible code changes. In addition to this, PAL's increased resolution was not utilized during conversion, creating a pseudo letterbox effect with borders top and bottom, leaving the graphics with a slightly squashed look due to an incorrect aspect ratio caused by the borders. This was especially prevalent during previous generations when 2D graphics were used almost exclusively. The gameplay of many games with an emphasis on speed, such as the original Sonic The Hedgehog for the Sega Mega Drive, suffered in their PAL incarnations.
Despite the possibility and popularity of 60Hz PAL games, many high profile games, particularly for the
PS2 console, were released in 50Hz-only versions. Square Enix have long been criticized by PAL gamers for their poor PAL conversions. Final Fantasy X runs in 50Hz mode only, and 17.5% slower and bordered that while prevalent in previous generations was considered inexcusable at the time of release. In stark contrast, the Xbox featured a system-wide PAL60 option in the Dashboard and the overwhelming majority of PAL games offered 50 and 60Hz modes with no slowdown. Current generation PAL consoles such as the Xbox 360 and Wii also feature system-wide 60Hz support.
Nintendo's Wii Virtual Console service has been criticised due to PAL games running in 50Hz only, despite the ability to run in 60Hz mode.
In recent times, several PAL releases have lacked the standard PAL mode and offered 60Hz only, including
Metroid Prime 2 for the Nintendo Gamecube and Dead or Alive 4 for the Xbox 360.

From Wikipedia, the free encyclopedia