As part of the survey, we asked respondents to indicate the importance of several wireless link attributes such as distance, latency or battery life. Each feature was given an importance score from 1 (completely unimportant) to 6 (very important). We then sorted the aggregate results by the average importance assigned to them by the users. Results were:
|Importance of various attributes of wireless video links for HMDs|
It seems that the highest priorities were assigned to these features that make the wireless link nearly transparent to the application: high refresh rate, low latency, closed-loop operation to include down link tracking and stereo operation. The combination of these features differentiate wireless video products designed for HMDs with those targeted towards in-home use primarily to extend the distance between the set top box and the HDTV. A 1/2 second video link latency, for instance, might be quite insignificant when watching a basketball game on TV, but is devastating to closed-loop virtual reality applications.
Another key difference between in-home HDMI extenders and professional HMD-driven wireless links is the transmission technology. In-home HDMI extenders typically use ultra-wide band or the new 60 GHz extremely high-frequency radio band. Both of these need line of sight between the wireless transmitter and the wireless receiver. However, imagine an HMD user wearing the receiver in a backpack and then turning around. The user's body can easily cut off the line of sight between transmitter and receiver. Thus, technologies such as Wireless N which are not sensitive to line of sight limitations are clearly preferable for wireless HMDs.
I believe that wireless video links will help unleash the true potential of the personal, portable HMD. The freedom of movement, multi-user interaction opportunities offered by wireless links are substantial and I'd expect many exciting applications to materialize in 2011.