The patent outlines a system that would reduce the likelihood of someone walking into furniture. Microsoft's system has special markers that would allow a VR headset to recognize the size of the play space on a mat and adjust the play area accordingly. The assumption is if your mat is a 6x12 space on the living room floor, that will be the limit of the play area in the VR game.
The patent says that the VR mat may include a "plurality" of spatially distributed pressure sensors integrated into it. The pressure sensors integrated into the mat could determine where the player is standing without requiring the position to be detected with an optical sensor. The mat may also provide haptic feedback with one or more vibration devices integrated into the floor mat.
One possible scenario for the mat outlined in the patent application uses interlocking tiles. Tiles of that sort would allow the user to define the size of their play space to fit their needs. Interestingly the patent mentions the Xbox One console as a possible device to drive the head-mounted display required in VR. Microsoft has backed away from the promise of VR on the Xbox and has positioned a PC as the driver for VR. As with all patents, there is no guarantee that this tech will ever come to market. Full PS4 cross-play capability is available for the Xbox allowing players on each console to compete against each other.