What do professional hockey and microelectronics have in common? A lot if you’re talking about enhanced goal-vetting capabilities.
VubIQ—a millimeter wave technology company—recently equipped 30 National Hockey League (NHL) venues throughout the U.S. and Canada with GoalCam systems for highly reliable goal adjudication. These systems, comprised of a GoalCam unit (HD camera and 60 GHz transmitter) and a 60 GHz receiver unit, are the result of a rigorous series of prototype testing and field trials with Palomar Technologies Assembly ServicesTM. Here is a deeper look into the completed project.
60 GHz Frequency Band
A solution for the NHL using wireless 60 GHz transmissions is ideal. Clearly, it would be infeasible to develop a cabled solution (using fiber or coax), as there would be no practical way to connect the GoalCam to outside of the rink. Additionally, other wireless frequencies come up short for two major reasons. First, lower frequency solutions like Wi-Fi do not have the bandwidth to transport uncompressed HD video, and would therefore need to compress the video at its source, transmit it across wirelessly, and then un-compress the video at the receive end. This would both add latency and, much more importantly, reduce video quality, which is critical. Second, these lower frequency solutions in unlicensed bands are subject to a great deal of interference, which can adversely affect, and even shut down, a wireless video stream. This would clearly be unacceptable to the NHL, and because of its unlicensed status, anyone with a Wi-Fi transmitter could, accidentally or maliciously, interfere with these transmissions.
While 60 GHz is also an unlicensed band, it differs from the lower unlicensed frequencies in two significant ways. The first is in terms of sheer bandwidth. While Wi- Fi spectrum allocation at 2.4 GHz is roughly 85 MHz wide, the unlicensed bandwidth allocated to 60 GHz is seven GHz wide – covering the entire band from 57-64 GHz in the US (and is the same or similar worldwide). This massive increase in bandwidth translates into much higher capacity channels that allow for the transmission of fully uncompressed high definition video at the standard rate of 1.485 Gbps. Therefore, there is no need to impact video quality or system latency by compressing the video stream. The other major difference from lower unlicensed frequencies is the directionality and very high spectral reuse capabilities at 60 GHz. As this implementation utilizes focused point-to-point antennas, it is nearly impossible to interfere with the signal, even in the highly unlikely case of someone at the arena actually having a functioning 60 GHz transmitter. This interfering signal would have to be in the direct path between the GoalCam transmitter and the overhead receiver, which for all practical purposes would be impossible.
GoalCam Unit
The GoalCam unit is a cylinder with shatterproof Lexan domes on either end for protection. Mounted in the upper back center of the goal inside the net, the unit is positioned vertically, slightly angled so that the bottom of the unit is pointed directly at the goal line. Inside the unit on the bottom end is a high definition video camera, statically focused on the goal line in 720p HD-SDI format. On the other end of the cylindrical unit is a 60 GHz transmitter and antenna, which are pointed up towards the rafters of the venue, where the receiver is located. The uncompressed HD video stream from the camera is modulated and transmitted at 60 GHz up to the receiver utilizing VubIQ’s patented techniques, at a range of up to 50 meters. The GoalCam unit has an internal rechargeable battery, capable of powering the unit for over 5 hours, as well as a port for connection to an external battery. Additionally, the unit can be Wi-Fi enabled, allowing for remote wireless adjustment of seven different functions, which include:
- Camera pan
- Camera tilt
- RF antenna pan
- RF antenna tilt
- HD camera focus
- HD camera iris
- HD camera zoom
A laser, aligned with the direction of the antenna, has also been built into the system, allowing for fast and easy alignment with the overhead receiver. The overall weight of the GoalCam unit is 4.5 pounds, which includes the 1.5 lb. battery.
60 GHz Receiver Unit
VubIQ’s 60 GHz receiver is an 8”x8”x9” box containing a fixed 34 dBi lensed horn antenna and all radio components required to receive incoming 60 GHz transmissions and convert them into a full rate (1.485 Gbps) uncompressed HD-SDI video stream for cabled transmission to the broadcast booth. The receiver is installed high above the rink, up to a range of 50 meters, with a line-of-sight connection to the GoalCam transmitter. Due to the proprietary and patented design of the baseband using discrete components, the latency of the signal from the antenna through the receiver and out the BNC connector is roughly 10 nanoseconds – essentially instantaneous. Alignment of the RF signal with the GoalCam is straightforward, with indicator lights on the front and back of the unit showing video lock and SMPTE error rate.
Once the 60 GHz transmission stream is received and down converted into HD-SDI format, the signal is ported out of the BNC connector at the back of the unit, and transmitted over coax cable to the booth, where it can be put to multiple uses, including:
- Local judging, using instant replay, back and forth slow motion, etc.
- Transmission to a remote judging location in Canada
- Local telecast to audience on large screens at arena
- Inclusion into broadcast stream for television audience
- Recording
Broadcast Booth
The broadcast booth is where the signal generated by the GoalCam is first viewed, either on a dedicated monitor, or in split screen with other video feeds. At this point the routing of the signal is like that of any other incoming video.
Graphical User Interface (GUI)
VubIQ’s simple and easy-to-use GUI allows for intuitive control over seven GoalCam functions. With the click of a mouse, installers or technicians can remotely adjust the camera, camera lens, and RF antenna from their laptops to optimize the system.
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Palomar Technologies would like to thank the VubIQ, Inc. team for guest blogging this week. Together, Palomar and VubIQ have enabled the most advanced approach to HD goal-capturing video for the NHL.
For more information about VubIQ, visit http://www.vubiq.com.