Short-Range Wireless Connectivity: A Complementary Comparison (cont.)

by Puneet Gupta

HomeRF

HomeRF is a subset of the International Telecommunication Union (ITU) and primarily works on the development of a standard for inexpensive RF voice and data communication.

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 an 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

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