Mobile VoIP

There are several methodologies by which a mobile handset can be integrated into a VoIP network. One implementation turns the mobile device into a standard SIP client, which then uses a data network to send and receive SIP messaging, and to send and receive RTP for the voice path. This methodology of turning a mobile handset into a standard SIP client requires that the mobile handset support, at minimum, high speed IP communications. In this application, standard VoIP protocols (typically SIP) are used over any broadband IP-capable wireless network connection such as EVDO rev A (which is symmetrical high speed — both high speed up and down), HSDPA, WiFi or WiMAX.

Another implementation of mobile integration uses a softswitch like gateway to bridge SIP and RTP into the mobile network's SS7 infrastructure. In this implementation, the mobile handset continues to operate as it always has (as a GSM or CDMA based device), but now it can be controlled by a SIP application server which can now provide advanced SIP based services to it. Several vendors offer this kind of capability today.

Mobile VoIP will require a compromise between economy and mobility. For example, Voice over Wi-Fi offers potentially free service but is only available within the coverage area of a Wi-Fi Access Point. High speed services from mobile operators using EVDO rev A or HSDPA may have better audio quality and capabilities for metropolitan-wide coverage including fast handoffs among mobile base stations, yet it will cost more than the typical Wi-Fi-based VoIP service.

Mobile VoIP will become an important service in the coming years as device manufacturers exploit more powerful processors and less costly memory to meet user needs for ever-more 'power in their pocket'. Smartphones in mid-2006 are capable of sending and receiving email, browsing the web (albeit at low rates) and in some cases allowing a user to watch TV.

The challenge for the mobile operator industry is to deliver the benefits and innovations of IP without losing control of the network service. Users like the Internet to be free and high speed without extra charges for visiting specific sites. Such a service challenges the most valuable service in the telecommunications industry — voice — and threatens to change the nature of the global communications industry.

Comparison of mobile phone standards

Global System for Mobile Communications (AKA GSM, around 80–85 % market share) and IS-95 (AKA cdmaOne, around 10–15 % market share^[1]) are the two most prevalent mobile communication technologies. Both technologies have to solve the same problem: to divide the finite RF spectrum among multiple users.

TDMA (Time Division Multiple Access—underlying technology used in GSM's 2G) does it by chopping up the channel into sequential time slices. Each user of the channel takes turns to transmit and receive signals. In reality, only one person is actually using the channel at a specific moment. This is analogous to time-sharing on a large computer server.

CDMA (Code Division Multiple Access—underlying technology used in GSM's 3G and IS-95's 2G) on the other hand, uses a special type of digital modulation called spread spectrum which spreads the voice data over a very wide channel in pseudorandom fashion. The receiver undoes the randomization to collect the bits together and produce the sound.

For comparison, imagine a cocktail party, where couples are talking to each other in a single room. The room represents the available bandwidth. In GSM, a speaker takes turns talking to a listener. The speaker talks for a short time and then stops to let another pair talk. There is never more than one speaker talking in the room, no one has to worry about two conversations mixing. In CDMA, any speaker can talk at any time; however each uses a different language. Each listener can only understand the language of their partner. As more and more couples talk, the background noise (representing the noise floor) gets louder, but because of the difference in languages, conversations do not mix

History

The first smartphone was called Simon; it was designed by IBM in 1992 and shown as a concept product^[10] that year at COMDEX, the computer industry trade show held in Las Vegas, Nevada. It was released to the public in 1993 and sold by BellSouth. Besides being a mobile phone, it also contained a calendar, address book, world clock, calculator, note pad, e-mail, send and receive fax, and games. It had no physical buttons to dial with. Instead customers used a touch-screen to select phone numbers with a finger or create facsimiles and memos with an optional stylus. Text was entered with a unique on-screen "predictive" keyboard. By today's standards, the Simon would be a fairly low-end product, however its feature set at the time was incredibly advanced.

The Nokia Communicator line was the first of Nokia's smartphones starting with the Nokia 9000, released in 1996. This distinctive palmtop computer style smartphone was the result of a collaborative effort of an early successful and expensive PDA model by Hewlett Packard combined with Nokia's bestselling phone around that time and early prototype models had the two devices fixed via a hinge; the Nokia 9210 as the first color screen Communicator model which was the first true smartphone with an open operating system; the 9500 Communicator that was also Nokia's first cameraphone Communicator and Nokia's first WiFi phone; the 9300 Communicator was the third dimensional shift into a smaller form factor; and the latest E90 Communicator includes GPS. The Nokia Communicator model is remarkable also having been the most expensive phone model sold by a major brand for almost the full lifespan of the model series, easily 20% and sometimes 40% more expensive than the next most expensive smartphone by any major manufacturer.

The Ericsson R380 was sold as a 'smartphone' but could not run native third-party applications.^[11] Although the Nokia 9210 was arguably the first true smartphone with an open operating system, Nokia continued to refer to it as a Communicator.

In 2001 RIM released the first BlackBerry which was the first smartphone optimized for wireless email use and has achieved a total customer base of 8 million subscribers by June 2007, of which three quarters are in North America.

Although the Nokia 7650, announced in 2001, was referred to as a 'smart phone' in the media, and is now called a 'smartphone' on the Nokia support site, the press release referred to it as an 'imaging phone'.^[12][13][14] Handspring delivered the first widely popular smartphone devices in the US market by marrying its Palm OS based Visor PDA together with a piggybacked GSM phone module, the VisorPhone. By 2002, Handspring was marketing an integrated smartphone called the Treo; the company subsequently merged with Palm primarily because the PDA market was dying but the Treo smartphone was quickly becoming popular as a phone with extended PDA organizer features. That same year, Microsoft announced its Windows CE Pocket PC OS would be offered as "Microsoft Windows Powered Smartphone 2002".^[15] Microsoft originally defined its Windows Smartphone products as lacking a touchscreen and offering a lower screen resolution compared to its sibling Pocket PC devices. Palm has since largely abandoned its own Palm OS in favor of licensing Microsoft's WinCE-based operating system now referred to as Windows Mobile.

Smartphone

A smartphone is a mobile phone offering advanced capabilities, often with PC-like functionality. There is no industry standard definition of a smartphone.^[1][2] For some, a smartphone is a phone that runs complete operating system software providing a standardized interface and platform for application developers.^[3][4] For others, a smartphone is simply a phone with advanced features like e-mail, Internet and e-book reader capabilities, and/or a built-in full keyboard or external USB keyboard and VGA connector. In other words, it is a miniature computer that has phone capability.^[5][6] Growth in demand for smartphones - devices boasting powerful processors, abundant memories, large screens and open operating systems - has outpaced the rest of the mobile phone market for several years.

Slider Cell Phones

A slider phone is composed of usually two, but sometimes more segments that slide past each other on rails. Most slider phones have a display segment which houses the speaker used for calls and the phone's screen, while another segment contains the keypad or keyboard and slides out for use. The goal of using a sliding form factor is to allow the operator to take advantage of full physical keyboards or keypads, without sacrificing portability, by "retracting" them into the phone when these are not in use.

The Siemens SL55 was one of first sliding mobile phones. Some phones have an automatic slider built in which deploys the keypad. Many phones will "pop out" their keypad segments as soon as the user begins to slide the phone apart. The forthcoming Palm Pre smartphone is a slider, as is the HTC Dream/T-Mobile G1.

Rigid form factors

A bar (or slab, or most commonly in the U.S., candybar) phone is in the shape of a cuboid.^[1][2] It is named because of its resemblance to a candy bar in size and shape. This form factor is widely used by a variety of manufacturers, such as Nokia and Sony Ericsson. Bar-type mobile phones normally have the screen and keypad all on one face. Many touchscreen phones such as the iPhone are candybar phones, but do away with keypads, favoring a touchscreen that covers the entire face of the phone. The Samsung SPH-M620 is a unique take on the bar form factor, offering different devices on either side of the bar; a phone on one side, and a digital audio player on the other.

Flip Cell Phones

The flip or clamshell is an electronics form factor which is in two or more sections that fold via a hinge. Motorola used to have a trademark on the term "flip phone",^[1] but the term "flip phone" has become genericized to be used more frequently than "Clamshell" in colloquial speech.

This design is often used in technology, particularly portable devices such as mobile phones, laptop computers, subnotebooks, the Game Boy Advance SP and the Nintendo DS. When the clamshell is open, the device is ready for use. The interface components are kept inside the clamshell, which offers more surface area than when the device is closed. Interface components such as keys and display are protected when the clamshell is closed, and it is less long or wide, making the device easier to carry around.

Camera phone

The camera phone, like many complex systems, is the result of converging and enabling technologies. There are dozens of relevant patents dating back as far as the 1960s.^{[citation needed]} Compared to digital cameras of the 90s, a consumer-viable camera in a mobile phone would require far less power and a higher level of camera electronics integration to permit the miniaturization. The CMOS active pixel image sensor "camera-on-a-chip" developed by Dr. Eric Fossum and his team^{[citation needed]}in the early 1990s achieved the first step of realizing the modern camera phone as described in a March 1995 Business Week article.^{[citation needed]} While the first camera phones, as successfully marketed by J-Phone in Japan, used CCD sensors and not CMOS sensors, more than 90% of camera phones sold today use CMOS image sensor technology.^{[citation needed]}

The first wireless picturephone prototype known as intellect, developed in 1993 by inventor Daniel A. Henderson^[1], was received by the Smithsonian National Museum of American History in 2007^[2]. This pioneering system and device was designed to receive pictures and video data sent from a message originator to a message center for transmission and display on a wireless device such as a cellular telephone ^[3]. However, the integration of the cellular phone, the digital camera and a wireless internet infrastructure would take a few more years.