Home Radio Frequency (HomeRF)

The other localized 2.4 GHz radio technology is HomeRF, which has many similarities to the Bluetooth wireless technology alluded to in the previous section. HomeRF can operate ad hoc networks (data only) or be under the control of a connection point coordinating the system. The system also provides a gateway to the telephone network (data and voice). The technology uses frequency hopping. The hop cycle is 8 Hz, whereas a Bluetooth link hops at 1,600 Hz.

In the simplest terms, HomeRF is wireless home networking - a way to connect PCs, peripherals, cordless phones, and many other consumer electronic devices so they can communicate with each other, sharing resources and access to the Internet. Wireless home networking makes this possible without the expense and complexity associated with running wires. In more technical terms, HomeRF is an open industry specification that defines how devices share and communicate voice, data, and streaming media in and around the home. HomeRF-compliant products operate in the license-free 2.4 GHz frequency band and utilize frequency-hopping spread spectrum (FHSS) RF technology for secure and robust wireless communications. HomeRF blends technologies from several worldwide standards because none of them alone could meet the market requirements. Data-networking technologies based on carrier sense multiple access with collision avoidance (CSMA/CA) protocols (essentially wireless Ethernet) are derived from the OpenAir and IEEE 802.11 standards, and cordless phone technologies based on Time Division Multiple Access (TDMA) are adapted from Digital Enhanced Cordless Telecommunications (DECT).^[34] HomeRF extends beyond WLAN home support - with 10 Mbps performance, a cordless telephone can support up to eight lines and QoS can support media streaming including music and TV and standardized roaming. Table 1-4 provides a comparison between a number of PAN technologies.^[35] It appears, however, that IEEE 802.11b will be the technology of choice for home networking.

Table 1-4. GHz PAN radios

Parameter	Bluetooth	HomeRF	IEEE 802.11 WPAN
Distance	10 meters	50 meters	Not determined
Hop rate	1,600 hertz	50 hertz	2.5 hertz
Transmit power	1 milliwatt	100 milliwatts (North America)	< 1 watt (United States) 100 milliwatts (Europe and Japan)

HomeRF was developed by the HomeRF Working Group (WG), which initially included five leading computer companies, but has since expanded to over 50 companies made up of leaders across the PC, consumer electronics, networking, peripherals, communications, software, retail channel, home control, and semiconductor industries worldwide. This group was launched in 1998 to promote the mass deployment of interoperable consumer devices that share and communicate voice, data, and streaming media in and around the home without the complication and expense associated with running new wires. The HomeRF WG is dedicated to developing wireless home networking products that are simple, secure, reliable, and affordable to the consumer. At the beginning of 2001, it announced its interest in increased transmission speeds and support for additional device types, applications, and services. In fall 2001, it announced the formation of a HomeRF European WG to focus on the European marketplace.

HomeRF is a blend of wireless Ethernet, cordless telephony, and streaming media. Using only one Internet connection, whether it is dial up, Digital Subscriber Line (DSL), or cable, each member of the family can wirelessly access the Internet and PC resources simultaneously, using his or her different laptops, PCs, or Web-based devices. Because HomeRF is derived from a blend of DECT^[36] (for TDMA voice networking) and IEEE 802.11 (for CSMA/CA data networking) and uses the globally available 2.4 GHz frequency band, it is the logical evolution of DECT for high-speed home networking and will benefit from DECT's large market and mature technology. Over 50 million DECT devices were sold in 2000, and by 2002, the installed base was expected to be over 200 million. That is 10 times the size of the WLAN market. The DECT technology is very mature; semiconductors are in their fifth generation and chip sets are sold for well under $10.

HomeRF products first entered the market in 2000 and had 1.6 Mbps performance, which is a logical match for DSL and cable modems. Nearly all of the early products were PC related and supported data applications. HomeRF 2.0 (introduced in 2001) has 10 Mbps performance and supports more phone lines and new features for digital music and Internet-based TV. Products that could enter the market include the first HomeRF cordless phones, web tablets, music devices, and the increased use of HomeRF in home gateways. Because HomeRF 2.0 is compatible with first-generation HomeRF products, the roadmap is evolutionary. HomeRF 3.0, which has an even greater bandwidth of more than 25 Mbps, will support streaming video with DVD quality. By then, we could see broader use of HomeRF in TV set-top boxes, video tablets, and multimedia servers.

^[34]These notes on HomeRF are based directly on material from http://homerf.org/learning_center/faq.html.

^[35]T. G. Zimmerman, 'Wireless Networked Digital Devices: A New Paradigm for Computing and Communication,' IBM Systems Journal 38, no. 4 (1999).

^[36]DECT is a digital wireless telephone technology intended for cordless phones. Formerly, it was called the Digital European Cordless Telecommunications standard; it was developed by European companies. DECT uses TDMA to transmit radio signals to phones. DECT is designed especially for a smaller area with a large number of users, such as in cities and corporate complexes. As an example of an application mode, users can have telephones equipped for both GSM and DECT (known as a dual-mode phone) and have them operate seamlessly.