Video Streaming Over Wi-Fi
When you get home--with your high-def, 3D movie stored on a flash drive--you plug the drive into your laptop and transfer it to your network file server over a gigabit Wi-Fi connection. A couple of minutes later, the movie is ready to stream via a 60GHz wireless link from your networked entertainment center to your wall-mounted HDTV.
Wired ethernet has consistently achieved higher data speeds than Wi-Fi, but wireless standards groups are constantly trying to figure out ways to help Wi-Fi catch up. By 2012, two new protocols--802.11ac and 802.11ad--should be handling over-the-air data transmission at 1 gbps or faster.
As a result, future users can have multiple high-definition video streams and gaming streams active across a house and within a room. Central media servers, Blu-ray players, and other set-top boxes can sit anywhere in the home, streaming content to end devices in any location. For example, an HD video display, plugged in with just a power cord, can stand across the room from a Blu-ray player, satellite receiver, or computer--no need for expensive, unsightly cables.
The 802.11ac and 802.11ad standards should be well suited for home use, though their applications will certainly extend far beyond the home. The names reflect the internal method of numbering that the engineering group IEEE uses: 802 for networking, 11 for wireless, and one or more letters in sequence for specific task groups (that's how we got 802.11a, b, g, h, n, and others).
The 802.11ac standard will update 802.11n, the latest and greatest of a decade's worth of wireless local area networking (WLAN) technology that began with 802.11b. With 802.11ac, wireless networking performance will leap from a theoretical top speed of 600 mbps to a nominal maximum of more than 1 gbps. In practice, the net data carried by 802.11ac will be likely be between 300 mbps and 400 mbps--up from 160 mbps or so for a good real-world 802.11n setup, and more than enough capacity to carry multiple compressed video streams over a single channel simultaneously. Or users may assign individual streams running on unique frequencies to a number of separate channels. Like 802.11n, 802.11ac will use many antennas for receiving and sending data wirelessly.
The 802.11ac flavor still won't have the capacity to carry lossless high-definition video (video that retains the full fidelity and quality of the raw source), however. Today, lossless video is common over wired connections after decompression or decoding of a data stream from a satellite, cable, or disc. The right hardware will be able to take the 802.11ac compressed data stream and send it directly to a decoder in an HDTV set; some HD sets already have this capability today. But when uncompressed video has to stream at a rate faster than 1 gbps, a speedier format must be used.
That's where 802.11ad comes in. It abandons the 2.4GHz and 5GHz bands of the spectrum (where today's Wi-Fi works) to the newly available 60GHz spectrum. Because the 60GHz spectrum has an ocean of frequencies available in most countries--including in the United States--you'll be able to use multiple distinct channels to carry more than 1 gbps of uncompressed video each.
Unfortunately, the millimeter-long waves that make up 60GHz signals penetrate walls and furniture poorly, and oxygen readily absorbs the waves' energy. So 802.11ad is best suited for moving data across short distances between devices in the same room. Apart from supporting fast video transfers, 802.11ad will permit you to move files or sync data between devices at speeds approaching that of USB 3.0--and 1000 times faster than Bluetooth 2.
The 802.11ad spec is one of three competing ideas for using the 60GHz band of the spectrum. The Wireless HD trade group, a consortium of consumer electronics firms, is focusing on video use of the 60GHz band, while the Wireless Gigabit Alliance (WiGig) is looking at networking and consumer uses. Membership in the various groups overlaps, making an interoperable and perhaps unified spec possible. Though 802.11ad doesn't specifically address video, it will be a generic technology that can accommodate many kinds of data. At a minimum, each group will work to prevent interference with one another's purposes.
The combination of 802.11ac and 802.11ad, coupled with USB 3.0, will allow you to position clusters of computer equipment and entertainment hardware around your home. USB 3.0 and gigabit ethernet might connect devices located in a cabinet or on a desk; 802.11ac will link clusters across a home; and 802.11ad will carry data to mobile devices, displays, and other gear within a room.
Allen Huotari, the technical leader at Cisco Consumer Products (which now includes Linksys products and ships millions of Wi-Fi and ethernet devices each year) says that the change in home networks won't result from "any one single technology in the home, but rather a pairing of technologies or a trio of technologies--wired and/or wireless--for the backbone and the wireless on the edges."
This means fewer wires and cables, better speeds, and higher-quality video playback than anything possible today. By 2012, both specifications should be readily available.