Virtual Reality

 

VRProj: Delivering 360-degree Video With Viewport-Adaptive Truncation [WPMC 2022]

[Webpage] [paper]

Delivering Virtual Reality (VR) content wirelessly involves projecting a 360-video into a 2D format and then encoding it to satisfy the wireless bitrate requirements. However, the popular equirectangular and cubemap projections offer little flexibility to adapt to changing bitrates and headset motion. In this work, we show that the truncated square pyramid projection offers high flexibility for network and headset motion adaptation. We adapt by tuning a truncation parameter that controls the video quality for different spatial regions in the 360-video. Depending on the video, our scheme improves average video quality by up to 1.1dB in PSNR and up to 4.6 in VMAF score compared to a non-adaptive baseline.

Tian Qiu, Ish Kumar Jain, Raini Wu, Dinesh Bharadia, Pamela Cosman

ULoc: a cm-accurate, low-latency and power-efficient UWB tag localization system [IMWUT 2021]

[ULoc-Webpage] [paper]

A myriad of IoT applications demand centimeter-accurate localization that is robust to blockages from hands, furniture, or other occlusions in the environment. To address these needs, we developed ULoc, a scalable, low-power, and cm-accurate UWB localization and tracking system. ULoc’s builds a multi-antenna UWB anchor and develops a novel 3D tracking algorithm to deliver a stationary localization accuracy of less than 5 cm and a tracking accuracy of 10 cm in mobile conditions.

Minghui Zhao, Tyler Chang, Aditya Arun, Roshan Ayyalasomayajula, Chi Zhang, Dinesh Bharadia

Enabling high-quality untethered virtual reality [NSDI 2017]

Today’s virtual reality (VR) headsets require a cable connection to a PC or game console. This cable significantly limits the player’s mobility and, hence, her VR experience. The high data rate requirement of this link (multiple Gbps) precludes its replacement by WiFi. Thus, in this paper, we focus on using mmWave technology to deliver multi-Gbps wireless communication between VR headsets and their game consoles. We address the two key problems that prevent existing mmWave links from being used in VR systems. First, mmWave signals suffer from a blockage problem, i.e., they operate mainly in line-of-sight and can be blocked by simple obstacles such as the player lifting her hand in front of the headset. Second, mmWave radios use highly directional antennas with very narrow beams; they work only when the transmitter’s beam is aligned with the receiver’s beam. Any small movement of the headset can break the alignment and stall the data stream. We present MoVR, a novel system that allows mmWave links to sustain high data rates even in the presence of a blockage and mobility. MoVR does this by introducing a smart mmWave mirror and leveraging VR headset tracking information. We implement MoVR and empirically demonstrate its performance using an HTC VR headset.

Omid Abari, Dinesh Bharadia, Austin Duffield, Dina Katabi

Cutting the cord in virtual reality [HotNets 2016]

Today’s virtual reality (VR) headsets require a cable connection to a PC or game console. This cable significantly limits the player’s mobility and hence her VR experience. The high data rate requirement of this link (multiple Gbps) precludes its replacement by WiFi. In this paper, we focus on using mmWave technology to deliver multi Gbps wireless communication between VR headsets and their game consoles. The challenge, however, is that mmWave signals can be easily blocked by the player’s hand or head motion. We describe a novel system design and algorithms that allow mmWave links to sustain high data rates even in the presence of blockage, enabling a high-quality untethered VR experience

Omid Abari, Dinesh Bharadia, Austin Duffield, Dina Katabi