原创 USB 3.0 makes itself comfortable at home

USB 2.0's first entry way to homes is computers and then televisions. Similarly, USB 3.0 entered homes on ultrabooks and laptops, and is now permeating consumers' digital homes through TVs, BluRay players, and WiFi routers.

Consumers are benefiting from the lower power consumption and higher data rates that USB 3.0 offers in many ways, such as connecting smart phones to TVs to share pictures with the family and adding a USB 3.0 hard drive to a WiFi router to make a family "cloud" for shared storage. There is a wide variety of digital home applications that will likely take off in 2013, and USB 3.0 systems on chip (SoCs) will be used in many of them.

First, a look back—CES 2011 was saturated with webcams running with TVs, both with the webcams mounted outside of the TV and connected via USB 2.0 ports. As shown in the figures below, Toshiba, Panasonic, Sony and other TV manufacturers showed off their products' integration with these external devices.

Samsung TV running Skype video conferencing with video camera mounted on top.

Toshiba TV running Skype.

Hisense TV with gesture control and USB video camera mounted underneath.

The Chinese company Hisense has four (four!) USB 2.0 ports integrated in a TV. With these ports, consumers can conveniently connect digital cameras and USB flash drives directly to the TV to share pictures and videos. And, of course, connect a web cam to the TV for video conferencing and even gesture control.

Faster transfer rates
TV chips in 2011 had USB 2.0 hosts fully integrated into the TV's SoC. This allowed TV makers to incorporate a single standard chip. Low-end TVs used the same chip, but did not provide the USB 2.0 ports on the outside of the TV. For the high-end TVs with USB ports, consumers could buy a USB video camera and mount it on their TV. Usually, the video camera was a specific model, sold only by the TV manufacturer. The same USB ports could be used to connect the TV to the internet with a WiFi USB dongle, or connect a digital camera or flash memory to view pictures or video. The Hisense TV allowed use of four applications at once.

More, faster data transfer requires USB 3.0
Fast forward to today. All major TV makers offer a built-in video camera for video conferencing. These systems use USB internally to connect the TV chip and the camera. For example, a Panasonic TV has three external USB ports.

Panasonic TV with three USB Ports as seen at CES 2013.
It is likely there is a 4th port used internally for a USB to WiFi connection. In at least one case, Samsung's Smart Interaction feature uses the camera for gesture control and face recognition, and its microphone for voice control.

While USB 2.0 throughput is sufficient for video conferencing, the higher demands of gesture control require USB 3.0. Why? Gesture control improves with higher resolution cameras, and at least two cameras. If you've seen a teardown of the Microsoft Kinect USB Video Camera, which is used for gesture control in video gaming, you'll see that it includes at least two imaging sensors. One camera captures a full-colour image of the action and displays the user on the screen. The second camera, which is infrared, coordinates with data from the video camera to map out the human body. The two data streams together make a 3D model of the body for fairly accurate mapping and fine gesture control.

However, gamers will tell you that this interface isn't sensitive enough. Improved sensor control requires more data from multiple angles. With more video data delivered at 1080p, 30 frames per second would need 1.7 Gigabits throughput per second. This is at least five times faster than the effective throughput of USB 2.0.

Trying to move this much video data through a USB 2.0 connection requires compression next to the image sensor, transmission over USB 2.0, and then decompression when it reaches the central processor. Compressing and decompressing the video produces unwanted delays due to the additional CPU cycles. For gamers, it means slower motion sensing and more lag—basically, slow response times between the gamer's motion and the TV/game's response.

Connections outside the TV
Moving forward, at least two USB 3.0 ports will be available on the outside of TVs, such as those found on the Panasonic Viera. Using these ports, consumers can connect a USB 3.0 hard drive to the TV for direct recording. Attaching USB 3.0 drives will allow recording of up to four high-definition (HD) channels at once. A 3 terabyte (TB) USB 3.0 hard drive will hold 300 hours and a 6 TB USB 3.0 hard drive can hold 600 hours of HD TV shows. The second port can be used for connecting to a USB 3.0 video camera for the transfer and display of HD or 4K videos.

USB 2.0 can't support recording multiple channels of HD, uncompressed, encrypted content, so USB 3.0 is required. While TVs can currently record four channels, future TVs will easily record more. Recording multiple HD channels requires high throughput. Compressed video might be handled with slower speeds, but minimising compression allows for faster display on the screen. Faster USB 3.0 throughput reduces lag and provides more reliable delivery of content to display and to storage. Faster delivery to storage also reduces the RAM required. If the TV has to wait to write data into storage (or hold data for display when reading from storage) then more RAM is required for buffering the video data. Reducing RAM has a direct impact on reducing the cost of a TV since RAM is not designed by the TV manufacturer—it is purchased from a third party. Removing a single bank of RAM can save more than $1USD per unit in the cutthroat TV market.

USB 3.0 in set-top boxes
Panasonic offers a BluRay player/DVR set-top box (BZT9300) with an included 3 TB hard drive and two USB 3.0 ports. Similar to a TV, users can connect two additional USB 3.0 hard drives to increase storage space.

Set-top boxes can also take advantage of USB 3.0 for WiFi applications. More importantly, USB 3.0 can be used internally on a set-top box hard drive. Using USB 3.0 inside the box allows the manufacturer to reduce costs by eliminating the need for a SATA host integrated into the main set-top box SoC. Instead of a SATA hard drive, designers can use a USB 3.0 hard drive for simplicity. USB 3.0 is needed outside the box for consumers' use, so adding an additional port directly on the SoC eliminates the need for another technology. The same USB drivers can be used both inside and outside the box, eliminating the need for SATA controllers, PHYs and software drivers.

Other home media systems allow consumers to watch media on TV using WiFi, USB 3.0, SD or HDMI sources. For example, the HiMedia 910A uses a Realtek SoC with a USB 3.0 host. The USB 3.0 ports can be used to plug in a digital camera, flash drive or hard drive to display pictures or video directly to a connected TV.

Connections inside the TV
Not all USB connections happen through external ports. Internally, USB is implemented on separate SoCs on the TVs' PCBs. Using a separate chip allows the TV manufacturer to postpone the decision of which USB peripheral to use.

USB 3.0 peripherals are plentiful in the PC market and prices are competitive. TV manufacturers can choose high quality or low cost components. Many TVs use Linux, and USB peripheral manufacturers often provide open source USB drivers to enable faster software development.

In the case of a video camera, TV manufacturers can choose a high-quality HD camera for high-end TVs with great optics and then swap it out for a low-cost HD camera with lower quality optics for mid- or low-end TVs. Again, the same USB chip can be used with either camera. Implementing USB 3.0 gives the TV manufacturer the flexibility to offer faster throughput for gesture sensing, when needed.

The higher throughput of USB 3.0 also makes it ideal for implementing WiFi in TVs. TV manufacturers can choose a cheaper, slower WiFi-N radio for mid-range TVs and a faster WiFi-AC radio for high-end TVs. If the WiFi technology advances during their product development cycle, they can choose the fastest, most advanced WiFi technology, like the upcoming WiFi-AC standard, for the highest performance TVs. Manufacturers can even choose other wireless radio standards such as WiGig, UWB or WirelessHD.

As we all continue to generate and transfer more data, USB 3.0 will be a differentiating feature in our personal electronics. USB 3.0 is the clear choice for both inside and outside digital home devices. Manufacturers can take advantage of the ubiquity of USB 3.0 products to drive down costs while leveraging USB 3.0's higher speed to deliver more performance with more recorded channels, more responsive gesture control, and smoother video display.

About the author
Eric Huang worked on USB at the beginning in 1995 with the world's first BIOS that supported USB keyboards and mice while at Award Software. After a departure into embedded systems software for real-time operating systems, Eric returned to USB cores and software at inSilicon, the leading supplier of USB IP in the world. inSilicon was acquired by Synopsys in 2002. Eric served as Chairman of the USB On-The-Go Working Group for the USB Implementers Forum from 2004-2006. Huang received an M.B.A. from Santa Clara University and an M.S. in Engineering from University of California Irvine, and a B.S. in Engineering from the University of Minnesota. He is a licensed Professional Engineer in Civil Engineering in the State of California.