Working of Smartphones

How Smartphones Work

Smartphones blur the line between cell phones and PDAs.

Think of a daily task, any daily task, and it's likely there's a specialized, pocket-sized device designed to help you accomplish it. You can get a separate, tiny and powerful machine to make phone calls, keep your calendar and address book, entertain you, play your music, give directions, take pictures, check your e-mail, and do countless other things. But how many pockets do you have? Handheld devices become as clunky as a room-sized supercomputer when you have to carry four of them around with you every day.

A smartphone is one device that can take care of all of your handheld computing and communication needs in a single, small package. It's not so much a distinct class of products as it is a different set of standards for cell phones to live up to. This article explores what makes a cell phone a smartphone, how the idea came about and what you can do with it.

­ Unlike many traditional cell phones, smartphones allow individual users to install, configure and run applications of their choosing. A smartphone offers the ability to conform the device to your particular way of doing things. Most standard cell-phone software offers only limited choices for re-configuration, forcing you to adapt to the way it's set up. On a standard phone, whether or not you like the built-in calendar application, you are stuck with it except for a few minor tweaks. If that phone were a smartphone, you could install any compatible calendar application you like.

Since cell phones and PDAs are the most common handheld devices today, a smartphone is usually either a phone with added PDA capabilities or a PDA with added phone capabilities. Here's a list of some of the things smartphones can do:

• Send and receive mobile phone calls – some smartphones are also WiFi capable
• Personal Information Management (PIM) including notes, calendar and to-do list
• Communication with laptop or desktop computers
• Data synchronization with applications like Microsoft Outlook and Apple's iCal calendar programs
• E-mail
• Instant messaging
  
• Applications such as word processing programs or video games
• Play audio and video files in some standard formats

­ Future applications promise to be even more impressive. For example, the Nokia 6131 is a phone utilizing near field communication (NFC) to allow the phone to act as a wireless credit card. The phone uses a two-way communication system to transfer payment information to pads at certain retail stores. Currently, it’s still in the trial phase of development.

The Layers of a Smartphone

The Hardware
Today's smartphones run on processors with clock speeds ranging from 100 – 624 MHz (with a 1 GHz processor looming on the horizon), which would be mind-numbingly slow if they were used to run today's desktop computers. Many smartphones use power-efficient ARM processors, which are also found in routers, printers, and other embedded devices like Smart Watches and MP3 players. They have a certain amount of on-board memory in the tens of megabytes, and many have slots for removable memory formats like SD and MMC cards as well.

Chips used in smartphones

Along with processors, smartphones also have computer chips that provide functionality. Phones with cameras have high-resolution image sensors, just like digital cameras. Other chips support complex functions such as real-time web browsing, sharing multimedia files or playing music without placing too great a demand on the phone’s battery. Some manufacturers develop chips that integrate multiple functions to help reduce the overall cost (fewer chips produced per phone help offset production costs).

The Innovations of Apple Apple’s iPhone has several hardware elements that are sure to become industry standards. The iPhone has an accelerometer that allows you to change the view from portrait to landscape layout by simply turning the phone 90 degrees. There are no dial buttons on the iPhone; all calls are made by using the touchscreen. In order to prevent you from accidentally dialing Peru when you talk on the phone, Apple has included proximity sensors to turn off the display when you lift the phone to your ear. There are also ambient light sensors that help the iPhone save power by adjusting the brightness of the display based on how much ambient light is present.

The Software
Software for smartphones can be visualized as a software stack. The stack consists of the following layers:

• kernel - management systems for processes and drivers for hardware
• middleware - software libraries that enable smartphone applications (such as security, web browsing, messaging, etc.)
• application execution environment (AEE) - application programming interfaces, which allow developers to create their own programs
• user interface framework - the graphics and layouts seen on the screen
• application suite - the basic applications users access regularly such as menu screens, calendars and message inboxes

Special Considerations Although cell phones share similarities with laptop computers, pagers and other devices, they have some peculiarities that make their development needs unique. For example: When you're making a call on a cell phone, you want to have access to other features (like an address book and calendar) at the same time. Cell phones need to be "always on" like a standard landline phone, but efficient enough to run on a battery charge for as long as possible. They need to be as functional as possible whether or not they are connected to voice and data networks at a given moment. While a computer has pretty standard input methods -- almost all of them start with a keyboard and mouse by default -- a phone may have a number pad, a modified keyboard, a touch screen or some combination thereof.

Smartphone Operating Systems

The most important software in any smartphone is its operating system (OS). An operating system manages the hardware and software resources of smartphones. Some OS platforms cover the entire range of the software stack. Others may only include the lower levels (typically the kernel and middleware layers) and rely on additional software platforms to provide a user interface framework, or AEE. The smartphone operating systems are:

A Nokia N92 with Symbian OS

Symbian
Symbian OS is the operating system for more than 100 different models of phones. The operating system consists of the kernel and middleware components of the software stack. The upper layers are supplied by application platforms like S60, UIQ, and MOAP. Though it's dominant in the market right now, with an estimated market share of 51 percent [Source: LinuxDevices.com],the research firm, The Diffusion Group, estimates that Linux and Microsoft will hold more of the market share than Symbian by 2010.

Linux

The Linux Smartphone

Linux is unique among the other operating systems in that its development is driven by a community of developers rather than by a central company. According to ARCchart, the Linux OS supports more processors than any other operating system on the market, though the most popular phone models still use the Symbian OS. There are some drawbacks to the system, however. Since Linux is an organic OS, with developers constantly changing and updating it even at the kernel level, platforms based on Linux code can be very different from one another. Some smartphone companies find the risk too great to invest in Linux. Six telecommunications companies are responding to this by forming the LiMo foundation, an organization that is attempting to create a standardized Linux platform.

Windows Mobile

The T-Mobile SDA Windows Mobile Smartphone

The Windows Mobile OS encompasses the entire software stack from the kernel to the application interface. The OS is based off of Window CE.NET. On February 12, 2007, Microsoft unveiled Windows Mobile 6, the latest version of the software platform. Much of the strength of this OS lies in the compatibility with the Microsoft Office suite of programs.

Java
Some smartphones have operating systems based on the Java programming language. The SavaJe OS is a Java-based system that includes everything from the kernel to the user interface framework and application suite. By using the Java language, the OS allows manufacturers or users to customize the interface as much as they like. Java-based phones have not made a huge impact in the marketplace so far, but some analysts think the operating system could gain ground while the big boys battle for the lion’s share of the market.

Garnet OS
Formerly known as Palm OS, this operating system combines a Linux-based foundation with applications written for the old Palm OS. The Palm OS was mainly used in PDAs, though the Treo line of smartphones used it as well. Phones using the Garnet OS should become available in late 2007.

Unique Operating Systems
Apple’s iPhone uses a variation of the Mac OS, known as OS X. The RIM BlackBerry has its own proprietary OS as well.

Network Protocols

Smartphones use cell-phone network technology to send and receive data (such as phone calls, web browsing, file transfers, etc.). Developers classify this technology into generations. The first generation includes analog cell phone technology. Digital cell phones require more advanced protocols, which constitute the second generation. Between generation two and three, network engineers created protocols that are more advanced than generation two’s digital technology but not so innovative that they are a truly new generation. Developers refer to these protocols as generation 2.5. This generation includes several early smartphone protocols, some of which are still used today.

Treo 700w: Palm's First Windows Mobile Smartphone

General Packet Radio Services (GPRS) is a wireless, packet-based communication service and until recently was the standard 2.5G protocol used in most smartphones. Unlike a circuit-switched voice connection, this is a packet-switched, "always on" connection that remains active as long as the phone is within range of the service. It allows smartphones to do things like run applications remotely over a network, interface with the Internet, participate in instant messenger sessions, act as a wireless modem for a computer and transmit and receive e-mails. GPRS can send and receive data at a rate of 114 kilobytes per second. Some smartphones in the United States still use this protocol, though newer, faster protocols are available.

One protocol that is faster than GPRS used in the U.S. market is Enhanced Data GSM Environment (EDGE). EDGE can transmit data at more than three times the rate of GPRS (384 Kbps). Many smartphones in the United States are now using EDGE protocol [Source: Whatis.com]. Still, these protocols are only generation 2.5. Generation three (3G) is the latest in network communication technology. Protocols in 3G transmit data in terms of megabytes per second rather than kilobytes (some as fast as 10 Mbps). While some U.S. carriers support 3G protocols, many still rely on 2.5G technology. Europe and Asia have much stronger 3G integration in their respective cell phone networks. Some 3G protocols are:

• Universal Mobile Telecommunication Service (UMTS)
• Wideband Code-Division Multiple Access (WCDMA)
• High-Speed Downlink Packet Access (HSDPA)
• Evolution Data Maximized (EVDO)

Talkin’ ‘bout my generation Even as smartphone owners in the United States begin to enjoy the benefits of 3G technology, the reality of a fourth generation of protocols may soon be upon us. On February 9, 2007, telecommunications company NTT DoCoMo Inc. revealed the results of a preliminary 4G experiment. Engineers also managed to achieve a 5Gbps (gigabyte per second) transmission rate [Source: NTT DoCoMo inc.]. That’s 500 times faster than 3G protocols!

You can read more about network technologies and protocols in the article How Cell Phones Work.

Flexible Interfaces

The core services on smartphones all tie in to the idea of a multi-purpose device that can effectively multitask. A user can watch a video clip, field a phone call, then return to the video clip after the call, all without closing each application. Or he or she can flip through the digital calendar and to-do list applications without interrupting the voice call. All of the data stored on the phone can be synchronized with outside applications or manipulated by third-party phone applications in any number of ways. Systems supported by smartphones include:

Bluetooth
A short-range, wireless radio service that allows phones to wirelessly link up with each other and with other nearby devices that support it. This includes things like printers, scanners, input devices , computers and headsets.

Some varieties of Bluetooth only allow communication with one device at a time, but others allow simultaneous connection with multiple devices. To learn more, check out How Bluetooth Works.

Data Synchronization
A phone that keeps track of your personal information, like appointments, to-do lists, addresses, and phone numbers, needs to be able to communicate with all of the other devices you use to keep track of those things. There are hundreds of possible platforms and applications you might use for this in the course of a day. If you want to keep all of this data in synchronization with what's on your phone, then you generally have to look for a cell phone that speaks the languages of all of the devices and applications you use. Or you can go out and buy new applications that speak the language of your cell phone.

Smartphone E-mail Application

The Open Mobile Alliance (OMA) is a collaborative organization with the mission to “facilitate global user adoption of mobile data services by specifying market driven mobile service enablers that ensure service interoperability across devices, geographies, service providers, operators, and networks, while allowing businesses to compete through innovation and differentiation” [Source: Open Mobile Alliance]. The OMA formed a Data Synchronization Working Group, which is continuing the work begun by the SyncML Initiative. SyncML is an open-standards project designed to eliminate the trouble of worrying about whether your PIM devices sync up with your phone and vice-versa. The project is designed so that any kind of data can be synchronized with any application on any piece of hardware, through any network, provided that they are all programmed to OMA standards. This includes synchronization over the Web, Bluetooth, mail protocols and TCP/IP networks.

SyncML allows data to be synchronized from a phone to PalmOS, Windows, Mac and Linux applications using Bluetooth, infrared, HTTP or a USB cable. The OMA's SyncML site keeps a list of devices that are compliant with the standard.

Java
A smartphone that is compatible with the Java programming language allows the user to load and run Java applications and MIDlets. MIDlets are applications that use a subset of Java and are specifically programmed to run on wireless devices. Java MIDlets include add-ons, games, applications and utilities.

Since there are millions of Java developers worldwide, and the Java development tools are freely accessible, smartphone users can install thousands of third-party applications on their phones. Because of the way the OS architecture of most phones is built, these applications can access and use all of the data on the user's phone. For example, if you don't like the photo caller ID that comes bundled with Symbian Series 60 OS, you can just find one that you like better.

The Future of Smartphones

Honey, can you get the door? A Dutch wireless company named Waleli has recently developed a way for you to answer your front door, even if you aren’t in the same country as your house. The doorbell and intercom system sends a message to your phone when activated. After you enter your PIN correctly, you can talk to your guest over the intercom, or even unlock your door to let them in.

Smartphones are getting thinner and cheaper, and as a result are entering the consumer market. For the past few years smartphones have been aimed at prosumers, or “professional consumers” (prosumers can also refer to “production consumers”, or consumers who drive the design, production and alteration of a product). Prosumers are generally early adopters of products. They have disposable income and great enthusiasm for particular products or technologies. Smartphone developers find prosumers very useful when designing applications and hardware. As prosumers pick and choose the phones that offer the applications they want, developers can tweak designs and move towards mass production. Analysts predict that one billion smartphone handsets will be sold by 2011 [Source: eCommerce Times].

While input methods will vary, the research firm, ARCchart, forecasts that 38 percent of all mobile phones will use touchscreens or touchpanels by 2012 [Source: LinuxDevices.com]. The iPhone uses an advanced touchscreen, for example, and can even detect multiple points of contact simultaneously.

Security
Perhaps the most challenging consideration for the future is security. Smartphones and PDAs are already popular among many corporate executives, who often use their phones to transmit confidential information. Smartphones may be vulnerable to security breaches such as an Evil Twin attack. In an evil twin attack, a hacker sets a server’s service identifier to that of a legitimate hotspot or network while simultaneously blocking traffic to the real server. When a user connects with the hacker’s server, information can be intercepted and security is compromised.

One downside to the openness and configurability of smartphones is that it also makes them susceptible to viruses. Hackers have written viruses that attack SymbianOS phones. The viruses can do things like turning off anti-virus software, locking the phone completely or deleting all applications stored on the phone.

On the other side, some critics argue that anti-virus software manufacturers greatly exaggerate the risks, harms and scope of phone viruses in order to help sell their software. Read more in the article How Cell Phone Viruses Work.

Symbian Skull Virus: Skulls will continuously display a flashing skull animation in the background regardless of what application the user is using.

The incredible diversity in smartphone hardware, software and network protocols inhibit practical, broad security measures. Most security considerations either focus on particular operating systems or have more to do with user behavior than network security.

With data transmission rates reaching blistering speeds and the incorporation of WiFi technology, the sky is the limit on what smartphones can do. Possibly the most exciting thing about smartphone technology is that the field is still wide open. It's an idea that probably hasn't found its perfect, real-world implementation yet. Every crop of phones brings new designs and new interface ideas. No one developer or manufacturer has come up with the perfect shape, size or input method yet. The next "killer app" smartphone could look like a flip phone, a tablet PC, a candy bar or something no one has conceived of yet.