Mobile phone GPRS Technology |The General Packet Radio Service
The General Packet Radio Service (GPRS) is a new non-voice value added service that allows information to be sent and received across a mobile telephone network. It supplements today's Circuit Switched Data and Short Message Service. It is a step ahead to provide a massive boost to mobile data usage and usefulness. Payments are made as per data volume, instead of per minute pulse rate. You need to pay a fixed rent around Rs. 750 per month, after which you can surf for unlimited hours. Except for one thing, as a developing technology, the net connection is a slow process.
Surfing the net; emailing; all through the mobile.
Fast transmission of text documents, spreadsheets, photographs and illustrations; mobile chatting and on-line games.
A round the clock net connection, even when you are on the move.
A GPRS can achieve speeds up to 171.2 kilobits per second (kbps) using all eight timeslots at the same time. This is thrice as fast as current data transmission systems.
GPRS facilitates instant connections whereby information can be sent or received immediately as the need arises, subject to radio coverage. No dial-up modem connection is necessary.
NEW APPLICATIONS, BETTER APPLICATIONS
GPRS facilitates several new applications that have not previously been available over GSM networks due to the limitations in speed of Circuit Switched Data (9.6 kbps) and message length of the Short Message Service (160 characters). GPRS will fully enable the Internet applications you are used to on your desktop from web browsing to chat over the mobile network.
WHAT DO YOU NEED FOR A GPRS ?
To begin with, a mobile phone or terminal that supports GPRS.
A subscription to a mobile telephone network that supports GPRS. § Knowledge of how to send and/ or receive GPRS information using their specific model of mobile phone, including software and hardware configuration.
A destination to send or receive information through GPRS. Whereas with SMS this was often another mobile phone, in the case of GPRS, it is likely to be an Internet address, since GPRS is designed to make the Internet fully available to mobile users for the first time.
KEY NETWORK FEATURES OF GPRS
PACKET SWITCHING GPRS
involves overlaying a packet based air interface on the existing circuit switched GSM network. This gives the user an option to use a packet-based data service. With GPRS, the information is split into separate but related "packets" before being transmitted and reassembled at the receiving end.
Efficient use of scarce radio resources means that large numbers of GPRS users can potentially share the same bandwidth and be served from a single cell. The actual number of users supported depends on the application being used and how much data is being transferred. Because of the spectrum efficiency of GPRS, there is less need to build in idle capacity that is only used in peak hours. GPRS therefore lets network operators maximise the use of their network resources in a dynamic and flexible way, along with user access to resources and revenues.
GPRS fully enables Mobile Internet functionality by allowing inter-working between the existing Internet and the new GPRS network.
LIMITATIONS OF GPRS
LIMITED CELL CAPACITY FOR ALL USERS
There are only limited radio resources that can be deployed for different uses- use for one purpose precludes simultaneous use for another. For example, voice and GPRS calls both use the same network resources. The extent of the impact depends upon the number of timeslots, if any, that are reserved for exclusive use of GPRS.
SPEEDS MUCH LOWER IN REALITY
Achieving the theoretical maximum GPRS data transmission speed of 171.2 kbps would require a single user taking over all eight timeslots without any error protection. Additionally, the initial GPRS terminals are expected to be severely limited- supporting only one, two or three timeslots. The bandwidth available to a GPRS user will therefore be severely limited.
APPLICATIONS OF GPRS
A wide range of corporate and consumer applications are enabled by nonvoice mobile services such as SMS and GPRS.
Because of its synergy with the Internet, GPRS would allow mobile users to participate fully in existing Internet chat groups rather than needing to set up their own groups that are dedicated to mobile users. Since the number of participants is an important factor determining the value of participation in the newsgroup, the use of GPRS here would be advantageous.
TEXTUAL AND VISUAL INFORMATION
You can receive information, which is in the form of not only text, but maps, graphs or other visuals.
Still images such as photographs, pictures, postcards, greeting cards and presentations, static web pages can be sent and received over the mobile network as they are across fixed telephone networks. It will be possible with GPRS to post images from a digital camera connected to a GPRS radio device directly to an Internet site, allowing near real-time desktop publishing.
You will also be able to receive moving images and receive transmission from anywhere.
You will also be able to use the GPRS for browsing the net. DOCUMENT SHARING/ COLLABORATIVE WORKING
Mobile data facilitates document sharing and remote collaborative working. This lets different people in different places work on the same document at the same time.
Dictating to a mobile phone, would simply not give sufficient voice quality to allow transmission to be broadcast or analyzed for the purposes of background noise analysis or voice printing. Since even short voice clips occupy large file sizes, GPRS or other high speed mobile data services are needed.
Non-voice mobile services can be used to assign and communicate new jobs from office-based staff to mobile field staff. Customers typically telephone a call center whose staff take the call and categorize it. Those calls requiring a visit by field sales or service representative can then be escalated to those mobile workers.
With up to half of employees typically away from their desks at any one time, it is important for them to keep in touch with the office by extending the use of corporate email systems beyond an employee's office PC. Since GPRS capable devices will be more widespread in corporations than amongst the general mobile phone user community, there are likely to be more corporate email applications using GPRS than Internet email ones whose target market is more general.
Internet email services come in the form of a gateway service where the messages are not stored, or mailbox services in which messages are stored. In the case of gateway services, the wireless email platform simply translates the message from SMTP, the Internet email protocol, into SMS and sends to the SMS Center. In the case of mailbox email services, the emails are actually stored and the user gets a notification on their mobile phone and can then retrieve the full email by dialing in to collect it, forward it and so on.
By linking Internet email with an alert mechanism such as SMS or GPRS, users can be notified when a new email is received.
REMOTE LAN ACCESS
Remote LAN applications encompasses access to any applications that an employee would use when sitting at their desk, such as access to the intranet, their corporate email services such as Microsoft Exchange or Lotus Notes and to database applications running on Oracle or Sybase or whatever. The mobile terminal such as handheld or laptop computer has the same software programs as the desktop on it, or cut down client versions of the applications accessible through the corporate LAN. This application area is therefore likely to be a conglomeration of remote access to several different information types- email, intranet, databases. This information may all be accessible through web browsing tools, or require proprietary software applications on the mobile device. The ideal bearer for Remote LAN Access depends on the amount of data being transmitted, but the speed and latency of GPRS make it ideal.
You may download sizeable data across the mobile network. This data could be a presentation document for a traveling salesperson, an appliance manual for a service engineer or a software application such as Adobe Acrobat Reader to read documents. The source of this information could be one of the Internet communication methods such as FTP (File Transfer Protocol), telnet, http or Java- or from a proprietary database or legacy platform. Irrespective of source and type of file being transferred, this kind of application tends to be bandwidth intensive. It therefore requires a high-speed mobile data service such as GPRS, EDGE or 3GSM to run satisfactorily across a mobile network.
Home automation applications combine remote security with remote control. Basically, you can monitor your home from wherever you are- on the road, on holiday, or at the office. If your burglar alarm goes off, not only do you get alerted, but you get to go live and see who are perpetrators are and perhaps even lock them in. You can program your video, switch your oven on so that the preheating is complete by the time you arrive home and so on. Your GPRS capable mobile phone really does become like the remote control devices we use today for our television, video, hi-fi and so on. As the Internet Protocol (IP) will soon be everywhere- not just in mobile phones because of GPRS but all manner of household appliances and in every machine- these devices can be addressed and instructed. A key enabler for home automation applications will be Bluetooth, which allows disparate devices to inter work.
WHAT IS BLUETOOTH TECHNOLOGY ?
Bluetooth, named after the renowned Danish King, Harold Bluetooth, is a short-range wireless connectivity standard.
Bluetooth is capturing the minds of the present day technologists, as a technology enabler for the wireless unification of a wide variety of portable devices like mobile PCs, mobile phones and the like. It does away with the cables and enables voice and data transfer between the devices through wireless networks called piconets.
The primary segments identified for Bluetooth application are: Cellular & PCS Mobile Phones, Digital Cordless Phones, Data Access Points, PC Cards and Adapters , Notebook & Desktop PCs, Handheld PCs & Palm Companions / PDA s, Digital Still Cameras, Output Equipment, Automotive and Industrial & Medical applications.
The technology behind it:
Bluetooth is a Radio Frequency (RF) specification for short-range, point-to-multi-point voice and data transfer. An advantage of Bluetooth is it's similarity to many other specifications already deployed and it's borrowing of many a feature from these specifications. The 2.4GHz band is used by IEEE 802.11 to enable wireless LAN connectivity. Bluetooth borrows specifications to enable file sharing and data transfers between devices from IrDA (a wireless specification that uses InfraRed light to connect devices). HomeRF SWAP, a specification aimed at small network of devices for the home environment, is another source for Bluetooth.
It is omni-directional and has a present nominal link range of 10cm to 10m, which can be extended to 100m, with increased transmitting power. Bluetooth operates in the 2.4GHz Industrial-Scientific-Medical (ISM) Band and uses a Frequency Hop (FH) spread spectrum technology in which packets are transmitted in defined time slots on defined frequencies. A full duplex information interchange rate of upto 1Mbps may be achieved in which a Time-Division Duplex (TDD) scheme is used.
A Bluetooth System:
A Radio Unit - consisting of a radio transceiver, which provides the radio, link between the Bluetooth devices.
A Baseband Unit - a hardware consisting of flash memory and a CPU. This interfaces with the radio unit and the host device electronics.
Link Management Software - a driver software or firmware which enables the application software to interface with the baseband unit.
An Application Software - this implements the user interface and is the application that can run on wireless.
BLUE TOOTH USAGE MODELS
The usage model being presented below are those which have been identified by the Bluetooth SIG's marketing group and helps us to get a peep into the vast areas of application of this wonderful standard.
The three-in-one phone: It can work as cordless phones connecting to the public switched telephone network at home and office and thus incurring the fixed line charge. It could function as a walkie-talkie with other telephones in the same office or building, without incurring any charge. This telephone can also connect to the cellular infrastructure and function as a cellular phone, incurring cellular charges. At home, your phone functions as a portable phone (fixed line charge). When you're on the move, it functions as a mobile phone (cellular charge). And when your phone comes within range of another mobile phone with built-in Bluetooth wireless technology, it functions as a walkie-talkie (no telephony charge).
The Internet Bridge: In this usage model, mobile phone or cordless modem functions as a modem to the PC, providing dial-up networking and fax capabilities without a need for physical connection to the PC. Use your mobile computer to surf the Internet wherever you are, and regardless of whether you're cordlessly connected through a mobile phone (cellular) or through a wire-bound connection (e.g. PSTN, ISDN, LAN, xDSL).
The Interactive Conference: Here, multiple data terminals, use a Local Access Network (LAN) access point as a wireless connection to a LAN. Once connected, the data terminals operate as if they were connected to the LAN via dialup networking. The terminals can access all of the services provided by the LAN. In meetings and conferences you can transfer selected documents instantly with selected participants, and exchange electronic business cards automatically, without any wired connections.
The file transfer usage model offers the ability to transfer data objects from one device to another. Object types include, among others, ***.xls,***.ppt,***.wav,***.jpg,***.doc files or entire folders, directories or streaming data formats. Also, this offers a possibility to browse the contents of the folders on a remote device.
The Ultimate Headset: The Headset, can be wirelessly connected for the purpose of acting as a remote device's audio input and output interface .The headset increases the freedom of movement while maintaining privacy. The headset can be typically used with a cellular headset, cordless handset or personal computer for audio input and output. This headset will also have the ability to answer incoming calls and then terminate them without physically manipulating the telephone handset.
Connect your wireless headset to your mobile phone, mobile computer or any wired connection to keep your hands free for more important tasks when you're at the office or in your car.
The Automatic Synchronizer: This provides a device-to-device synchronization of the personal information management (PIM) information. Synchronization requires business card, calendar and task information to be transferred and processed by computers, cellular phones and PDA s, utilizing a common protocol and format. This involves, automatic synchronization of your desktop, mobile computer, notebook (PC-PDA and PC-HPC) and your mobile phone. For instance, as soon as you enter your office, the address list and calendar in your notebook will automatically be updated to agree with the one in your desktop, or vice versa.
IrDA AND BLUETOOTH
IrDA-Data (IrDA -> Infra-red Data Association) is another short-range wireless connectivity standard with an installed base of 50 million units, by now. IrDA is a point-to-point, narrow angle (30 degree cone), ad-hoc transmission standard designed to operate over a distance of 0 to 1 meter and at speeds of 9.6kbps to 4Mbps, which is expected to increase to 16Mbps.
While the application areas of Bluetooth and IrDA overlap, they are not competitive standards, necessarily. The short range, narrow angle of IrDA allows the user to aim, in point-and-shoot style at a targeted recipient, for example in a conference hall. Close proximity to the other person is natural in a business card exchange situation and the short range is an advantage of IrDA for such applications.
The directional nature of IR enables a low level security because of direct line-of-sight nature; but it provides for, no security at the link level. There are security loopholes as it is possible to eavesdrop on a conversation by detecting reflected light and filtering out the surrounding ambient noise.
In contrast, Bluetooth addresses the security concerns by providing authentication and encryption in its baseband protocol. Authentication relies on a challenge-response protocol utilizing a secret key, personal identification number or PIN. Bluetooth devices talking to one another should have the same PIN. The protocol allows each device to authenticate the other. After the devices are authenticated it is possible to encrypt the transmission for added security.
Thus, it is expected that while in some devices both IR and Bluetooth may co-exist, for the other applications, the choice of Bluetooth and IR will be based on the applications and required usage models.
Mind-boggling technology like the Bluetooth and GPRS, is on its way to make communications in the future, a completely different ball game. A ball game with a win-win situation. Pave way for the future with these technologies then