  Wireless Virtual Reality (VR) and Augmented Reality (AR) will contribute to
people increasingly working and socializing remotely. However, the VR/AR
experience is very susceptible to various delays and timing discrepancies,
which can lead to motion sickness and discomfort. This paper models and
exploits the existence of multiple paths and redundancy to improve the timing
performance of wireless VR communications. We consider Multiple Description
Coding (MDC), a scheme where the video stream is encoded in Q streams (Q = 2 in
this paper) known as descriptors and delivered independently over multiple
paths. We also consider an alternating scheme, that simply switches between the
paths. We analyze the full distribution of two relevant metrics: the packet
delay and the Peak Age of Information (PAoI), which measures the freshness of
the information at the receiver. The results show interesting trade-offs
between picture quality, frame rate, and latency: full duplication results in
fewer lost frames, but a higher latency than schemes with less redundancy. Even
the simple alternating scheme can outperform duplication in terms of PAoI, but
MDC can exploit the independent decodability of the descriptors to deliver a
basic version of the frames faster, while still getting the full-quality frames
with a slightly higher delay.
