NEC develops wireless system for high-definition video

NEC has developed a wireless technology that could link uncompressed HD signals to devices within the living room.

NEC has developed a wireless system that can transmit uncompressed high-definition (HD) video signals and could eliminate the need for cables when connecting HD-capable products, the company said. Systems based on the technology could be available in 2007.

Over the next few years, more and more products using HD video will emerge, chief manager of NEC's System Devices Research Laboratories, Hidenori Shimawaki, said.

With the products will come a need to interconnect them with a system that doesn't degrade the HD picture.

At present, most systems compress the HD signal, which can be around 1Gbps in bandwidth, to a fraction of its size to allow for transmission between devices. However, with each compression and subsequent decompression of the signal, some data can be lost and the picture quality can be reduced slightly.

A new system called High-Definition Multimedia Interface (HDMI) can transfer uncompressed HD signals between devices via a cable. And while consumer electronics makers are beginning to offer HDMI-compatible equipment, there is not yet a suitable wireless technology that is capable of transmitting uncompressed HD signals, Shimawaki said.

Wireless LAN and similar technologies can suffer interference issues when several devices are connected and they do not have the bandwidth to carry the uncompressed HD signal. Ultra wideband (UWB) technology offers higher bandwidth and can transmit HD signals without compressing them but works over a relatively close range and is yet to be commercialised.

NEC's prototype transmitters and receivers have overcome such speed, range and interference hurdles, according to Shimawaki.

In the system, the HD signal is converted into a 1Gbps data stream, which is enough to carry the signal between devices without the need for compression and decompression. The technology works to a range of about 7 metres, which is enough to work well in most living rooms, Shimawaki said.

The signal uses the unlicensed 60GHz band, which is largely unused and has few interference issues, he said.

The transmitters and receivers developed by the company measure 70mm x 50 mm x 15mm. NEC plans to make these smaller and may offer the technology to other consumer electronics companies, according to Shimawaki.

"The technology could be embedded in other devices, or it could be sold as an optional unit," he said.