High-definition technology has revolutionized television with incredibly clear pictures, but it hasn’t addressed a nagging problem at the back of the set—that tangled bunch of cables. Those cords may soon be cut as the wireless communications juggernaut finally conquers the living room. While technology may clear out the mess behind the set, consumers, however, will still have to untangle the knots of unfamiliar jargon and acronyms used by competing companies, organizations and standards.
Over the years, wireless applications have evolved from voice to data to video, but high-definition has been a hurdle. The reason is because that, by definition, HD involves moving a lot of data very quickly from the set-top box or media player to the TV for a seamless picture. That’s why you need those HDMI cables that you had to buy to go with the new HDTV. Traditionally, wireless applications have used compression techniques to pare down the amount of video data transmitted. The data is compressed at one end, then decompressed at the other. That can lead to delays at the viewing end and also degrade the picture quality. HDMI cables transmit the video uncompressed, so there’s no change to picture quality and no delays, or “latency.”
The challenge with wireless HDTV then is to be able to transmit that video data fast enough to keep the show moving along without noticeable delays or other screen effects. Everyone is familiar with Internet videos that stop and stall or even Internet pictures that take a few seconds to load. No one wants to watch a movie that way if they don’t have to. Even with increased speed, though, regular home Wi-Fi networks can’t move video data fast enough. That’s where the new technology and the new acronyms come in, such as Wireless HD and WHDI.
Wireless HD and WHDI, or Wireless Home Digital Interface, work in two different bands of the wireless spectrum, but both send video wirelessly to the TV. Wireless HD uses the 60 gigahertz (GHz) band of spectrum in the extremely high-frequency radio portion of the spectrum. This band sends data at a few gigabits (billion bits) per second, compared to a few hundred megabits per second for the latest Wi-Fi standard and around 50 megabits for the widely used Wi-Fi “g” standard. This greater data capability is why you’ll be hearing more about 60 gigahertz Wi-Fi in the very near future.
Wireless HD offers speeds up to four gigabits per second, which is fast enough to carry uncompressed HDTV signals. The problem with the 60 Ghz band, however, is that it has an effective range of about 33 feet and it’s sensitive to obstructions, such as walls and people. That means it usually needs a clear line of sight, which is unlikely to be an issue if the signal is traveling from a shelf to the wall – unless you have a very big and crowded room. TV makers including Vizio, Toshiba and Panasonic are now building sets including Wireless HD chips from semiconductor company Sibeam. For existing sets, Wireless HD adapters are available to replace the HDMI cable, though they’re not cheap.
The WHDI standard transmits data at up to three gigabits per second and operates in the five GHz band of spectrum. The range extends beyond 100 feet and the signals can pass through walls. This enables TVs in the bedroom, for instance, to play video from the living room set-top box or a TV in the basement to play a video game from a game player in the den. The technology sends uncompressed video but works by expediting the most important visual bits and giving lower priority to the least important bits. While you could play a movie in the bedroom from the DVR in the den, you wouldn’t be able to watch different shows on different TVs at the same time from the same set-top box. Backing the WHDI standard are chipmaker Amimon and consumer electronics companies Hitachi, Motorola, Samsung, Sony and LG Electronics.
While those two standards may get rid of the video cable running between the set top box and the TV, that still leaves the power cord. Start-up company WiTricity seeks to commercialize “wireless” electricity based on technology developed by physicists at the Massachusetts institute of Technology. That technology transfers power to devices around the room using the magnetic field associated with electricity. With that in place, you could finally cut the final cord.