Competing Technologies
(Major Portion of Content Provided by Puneet Gupta - a MobileInfo Technology Writer) 

Besides Bluetooth many other technologies exist like IrDA, Home RF (SWAP) that provide similar or related services. A quick glance into their scope and properties would help putting all of these into perspective. Lets look at the features of Bluetooth first (for the sake of comparison)

• Operates in the 2.56 GHZ ISM band which is globally available
• Uses FHSS
• Can support up to 8 devices in a piconet
• Omni-directional, non line of sight transmission through walls
• 10m to 100m range
• Low cost, $20
• 1mW power
• Extended range with external power amplifier (100 meters)

IrDA
IrDA is an international organization that creates and promotes interoperable, low-cost infrared data interconnection standards. IrDA has a set of protocols covering all layers of data transfer and in addition has some network management and interoperability designs. IrDA protocols have IrDA DATA as the vehicle for data delivery and IrDA CONTROL for sending the control information. [Feng99] [Williams00] IrDA DATA defines a standard for an interoperable universal two way cordless infrared light transmission data port. Adapters now include the traditional upgrades to serial and parallel ports

Features:

• Range: From contact to at least 1metre. Can be extended to 2 meters. A low power version relaxes the range objective for operation from contact through at least 20 cm between low power devices and 30 cm between low power and standard power devices. This implementation affords 10 times less power consumption. These parameters are termed the required maximum ranges by certain classes of IrDA featured devices and sets the end user expectation for discovery, recognition and performance.
• Bi-directional communication is the basis of all specifications
• Data transmission from 9600 b/s with primary speed/cost steps of 115 kb/s and maximum speed up to 4 Mb/s
• Data packets are protected using a CRC (CRC-16 for speeds up to 1.152Mb/s and CRC-32 at 4 Mb/s).

IrDA vs Bluetooth
If you examine the benefits of each technology, you can see that Bluetooth and IrDA are both critical to the marketplace. Each technology has advantages and drawbacks and neither can meet all users' needs. Bluetooth's ability to penetrate solid objects and its capability for maximum mobility within the piconet allows for data exchange applications that are very difficult or impossible with IrDA. For example, with Bluetooth a person could synchronize their phone with a PC without taking the phone out of their pocket or purse (this is not possible with IrDA). The omni-directional capability of Bluetooth allows synchronization to start when the phone is brought into range of the PC.

The Bluetooth standard defines the layers 1 and 2 of the OSI model. The application framework of Bluetooth is aimed to achieve interoperability with IrDA and WAP. In addition, a host of other applications will be able to use the Bluetooth technology and protocols.

Click here for a comparison of irDA and Bluetooth by Counterpoint division of Extended Systems.  Please note that Extended Systems has joined 3COM in developing Windows-based applications development tools for Bluetooth applications.

HOME RF
The HomeRF is a subset of the International Telecommunication Union (ITU) who is working on the development of a standard for inexpensive RF voice and data communication. Currently, the HomeRF Working Group specification provides for wireless Ethernet transmission.

• Range: Maximum 40 meters
• Data rates of 1.2Mbps

The HomeRF Working Group has also developed the Shared Wireless Access Protocol (SWAP). SWAP is a industry specification that permits PCs, peripherals, cordless telephones and other devices to communicate voice and data without the usage of cables. SWAP is similar to the CSMA/CA protocol of IEEE 802.11 but with an extension to voice traffic. The SWAP system can either operate as an adhoc network or as a infrastructure network under the control of a connection point. In an adhoc network, all stations are peers and control is distributed between the stations and supports only data. In an infrastructure network, a connection Point is required so as to coordinate the system and it provides the gateway to the PSTN (Public Switched Telephone Network). Walls and floors don't cause any problem in its functionality and some security is also provided through the use of unique network IDs. It is robust, reliable and minimizes the impact of radio interference.

Features:

• operates in the 2.45 GHz range of the unlicensed ISM band
• Range: upto 150 feet
• employs frequency hopping at 50 hops per second
• It supports both a TDMA service to provide delivery of interactive voice and CSMA/CA service for delivery of high speed data packets
• The network is capable of supporting upto 127 nodes
• Transmission Power : 100mW
• Data Rate : 1Mbps using 2FSK modulation and 2 Mbps using 4 FSK modulation
• Voice connections : upto 6 full duplex conversations
• Data Security : Blowfish encryption algorithm (over 1 trillion codes)
• Data Compression : LZRW3-A algorithm

SWAP vs Bluetooth
Currently SWAP has more installed base compared to Bluetooth but it is believed that Bluetooth is eventually going to prevail. Bluetooth is a technology to connect devices without cables. The intended use is to provide short-range connections between mobile devices and to the Internet via bridging devices to different networks (wired and wireless) that provide Internet capability. HomeRF SWAP is a wireless technology optimized for the home environment. Its primary use is to provide data networking and dial tones between devices such as PCs, cordless phones, Web Tablets and a broadband cable or DSL modem. Both technologies share the same frequency spectrum but do not interfere when operating in the same space. [Derfler00]

A quick glance comparison between these technologies is presented below.

More Information on Bluetooth

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