New Spec Supports Wireless Multimedia

Home and small-business users seeking to connect bandwidth-hungry audio and visual devices will appreciate a new standard for streaming multimedia data over high-speed wireless networks.

The new 802.15.3 standard for high-rate wireless personal area networks (WPANs) allows these networks to link as many as 245 wireless fixed and portable devices at data rates up to 55 megabits per second. It can support the signal at distances ranging from a few inches to 300 feet, according to the Institute of Electrical and Electronics Engineers (IEEE).

Range of Speeds

The standard, which substantially increases the initial 1-mbps speed of WPANs, comes in response to strong demand from users, the IEEE says. Users want to connect multiple portable devices at low cost, yet run high-bandwidth applications, such as multimedia, digital images, and high-quality video. The standard also addresses user priorities such as network economy, frequency performance, power consumption, and data-rate scalability, according to the IEEE.

To keep costs low, the IEEE limits the need for external components and allows the radio and protocol to appear on no more than two chips that fit within a CompactFlash card.

The new WPAN standard uses the 2.4 GHz unlicensed frequency band and specifies raw data rates of 11, 22, 33, 44, and 55 mbps.

Distance plays a role in transmission speed. The closer the device is to the access point, the higher the bandwidth. For instance, a device up to 165 feet away from an access point can transmit data at a speed of 55 mbps, while the transmission speed of a device 300 feet away drops to 22 mbps.

The highest rate, 55 mbps, is necessary for low-latency, multimedia connections and large-file transfers. The 11-mbps and 22-mbps rates are ideal for long-range connectivity for audio devices, the IEEE says.

Compatibility Promised

Moreover, 802.15.3 offers reliable quality of service, according to the IEEE. The technology uses time division multiple access (TDMA) to allocate channel time among devices to prevent conflicts and only provides new allocations for an application if enough bandwidth is available.

Fixed and portable devices in a WPAN connect in an ad hoc way and communicate by peer-to-peer networking, allowing them to connect without user intervention. The Advanced Encryption Standard (AES 128), approved by the U.S. government in 2001 to replace the older Data Encryption Standard (DES), ensures that data is protected in the network.

The 802.15.3 standard allows networks based on this specification to coexist with other 802.15 WPANs, such as Bluetooth systems, and with 802.11 WLANs, especially 802.11b and 802.11g, which also operate in the 2.4-GHz band.