Qualcomm and LeTV demonstrated 4K video streaming from a LeTV smartphone to an Ultra HDTV.
Last month, I mentioned several of the more intriguing products and technology demonstrations I saw at the 2016 International CES in January. One of those was the long-awaited emergence of 60GHz wireless connectivity, something I’ve been waiting for since SiBEAM was experimenting with wireless HDMI connections almost a decade ago.
“Going wireless” is definitely one of the space shots of the AV industry. We’ve been using it since the halcyon days of VHF wireless microphones, but there’s always a stumbling block: Limited bandwidth, in-band and adjacent channel interference, intermodulation distortion, and multipath and signal cancellation plagued those early wireless mic systems.
Later on, we migrated to the UHF television band, and diversity reception was invented. That solved a multitude of problems, but it still wasn’t practical to stream anything other than narrow-band FM audio; video just took up too much spectrum.
As 802.11 WiFi rolled out, we saw crude attempts to send still JPEG images from laptops to projectors. These systems worked most of the time, but had too much latency and often dropped connections. Attempts were made to stream SD and then HD video over the 2.4GHz 802.11a/n band, first using component video and then HDMI connections. These products also worked on a hit or miss basis…okay for consumer use, but not suited to more critical AV applications.
Several years ago, the first 5GHz wireless video links (Wireless High Definition Interface, WHDI) were shown at CES. This technology met with much more success and, in fact, I used it to demonstrate wireless 1080p HD streaming from a Nook tablet for a few years during my InfoComm classes. The inventor of the WHDI system, Amimon Semiconductor, has now shifted its focus to wireless high-bandwidth camera links for drones, although you can still buy WHDI transmitter-receiver kits from several manufacturers.
Although 2.4 and 5GHz wireless products showed promise, the 60GHz prototypes I tested were much more enigmatic. Unlike 2.4 and 5GHz signals, 60GHz radio waves are largely obstructed by any kind of solid object, from walls and furniture to the human body. Their wavelength is tiny (about .05 inch), which makes it possible to design and fab a complete transmitter with antennas onto a tiny chip.
The receiver can also be fabbed onto a chip along with multiple, steerable arrays of antennas to compensate for signal reflections and out-of-phase echo cancellation. Some early wireless HDMI connectivity kits using the SiBEAM technology worked very well in that regard (you could establish a link between a Blu-ray player and a TV, and walk in front of the TV, blocking the signal) only to have the TX/RX link immediately switch to a “bounced” signal off the ceiling or wall.
SiBEAM, which almost went bankrupt, was acquired by Silicon Image (SI) in 2011. And SI was, in turn, acquired by Lattice Semiconductor a year ago. The name has been revived, and SiBEAM showed demonstrations of UHD (4K) wireless streaming at CES, along with its SNAP close-proximity air gap wireless link that, when connected, provides 6Gb/s upstream and 6Gb/s downstream links for streaming data, video and audio from smartphones and tablets.
There’s another player at 60GHz. A few years back, the Wireless Gigabit (WiGig) Alliance came into existence to promote a new IEEE wireless standard: 802.11ad. This standard uses the same channels as SiBEAM’s products, starting at 57GHz and stopping at 65GHz. There are four channels, each 2GHz wide, that are allocated for unlicensed operation in this band with a maximum power of +30dBi.
Qualcomm demonstrated a number of prototype tri-band modems.
Not much was heard from WiGig until this year, when Qualcomm showed a table full of tri-band modems, supporting 2.4, 5 and 60GHz operation. In addition, Qualcomm partnered with Chinese manufacturer LeTV to demonstrate 4K video streaming from a LeTV smartphone to an Ultra HDTV, using no forward error correction or real-time protocols. It worked, but the video frequently stuttered and dropped frames.
Qualcomm also showed file uploads and downloads to that same LeTV phone at rates as high as 2.2Gb/s! That’s fast enough for me to download an HD movie to my Samsung Galaxy Tab in about four seconds. In theory, it should be possible to hit speeds as high as 3Gb/s with 802.11ad wireless links.
Over at the Westgate Hotel in Vegas, Peraso showed prototype USB-connectible 60GHz link dongles that could be used for everything from swapping and downloading files to streaming 4K video and audio. Only in their case, there were no dropouts, even though no forward error correction and streaming protocols were used. Peraso thinks there will be a big market for 60GHz connectivity with existing laptops and desktops; hence, the “chip in a plug” design I saw in their suite.
The fact that 60GHz links are so directional and limited to in-room operation makes them very appealing to security-minded folks. Think of connecting your laptop, tablet or smartphone to one of the new collaboration products that have become so popular these days; most of them use 2.4GHz WiFi adapters. But that’s a very crowded part of the spectrum, and 2.4GHz signals can pass through non-metallic walls and surfaces.
Even 5GHz signals can penetrate walls. I’m writing this column on a computer sitting two floors above my 5GHz wireless modem, and there’s plenty of signal available to establish a working link. At 60GHz, I wouldn’t see the signal at all. In a medium-sized conference room, the signals would largely fade out after about 30 feet.
Another property of 60GHz waves is their highly directional characteristic, thanks to beam-steering technology. At 600MHz, the isolation between a horizontally polarized signal and a vertically polarized one can be as much as 20dB. At 60GHz? You could have two signals operating on the same frequency and even crossing paths, and they’d never see each other.
For someone trying to “snoop” a 60GHz signal, the task would be quite difficult because you’d have to stand directly in the path of the transmitter link with an appropriate antenna. You’d also need some knowledge of the security keys used to protect the link, and that could be something as robust as 128-bit AES encryption, which even the NSA hasn’t cracked.
I suspect that there are few manufacturers in our industry who are aware of these new wireless products or their potential as secure, high-bandwidth video streaming links. As I mentioned earlier, there have been some attempts at selling wireless HDMI kits, but their prices have been too high to be practical; it was cheaper to just buy longer HDMI cables.
But the advent of Display Stream Compression (DSC), channel-bonding protocols like 802.11ac, and the higher bandwidths offered by 60GHz operation, will inevitably converge, giving a long awaited (and well deserved) farewell to many of the cables we now use in our AV installations. It won’t happen overnight, but it will happen….