The ultimate goal of virtual reality (VR) is to create an experience indistinguishable from actual reality. To provide such a "life-like" experience, (i) the VR headset (VRH) should be wireless so that the user can move around freely, and (ii) the wireless link, connecting the VRH to a high-performance renderer, should support high data rates (tens to hundreds of Gbps). Industry is already pushing towards such wireless VRHs; however, these wireless links can only support a few Gbps rates. In general, current radio-frequency (RF) links (including mmWave) are not able to provide desired data rates. In this paper, we build a system, we call Cyclops, which uses free-space optical (FSO) technology to create a high-bandwidth VR wireless link. FSO links are capable of very high data rates (up to Tbps) due to the high frequencies of light waves and narrow beams. The main challenges in developing an effective FSO link are: (i) designing a link with sufficient movement tolerance, and (ii) developing a viable tracking and pointing (TP) mechanism which maintains the link while the VRH moves. As traditional TP approaches seem infeasible in our context, we develop a novel TP approach based on learning techniques, leveraging the VRH's inbuilt tracking system. We build robust 10 Gbps and 25Gbps link prototypes from commodity components, demonstrate their viability for expected movement speeds of a VRH, and show that, with certain custom-built components, we can support much higher movement speeds and bandwidths.

Expected increase in cellular demand has pushed recent interest in picocell networks which have reduced cell sizes (100-200m or less). For ease of deployment of such networks, a wireless backhaul network is highly desired. Since RF-based technologies are unlikely to provide the desired multi-gigabit data rates, we motivate and explore use of free space optics (FSO) for picocell backhaul. In particular, we present a novel network architecture based on steerable links and sufficiently many robust short-range links, to help circumvent the key challenge of outdoor effects in reliable operation of outdoor FSO links. Our architecture is motivated by the fact that, due to the high density of picocells, many short-range links will occur naturally in a picocell backhaul. Moreover, use of steerable FSO links facilitates networks with sufficient redundancy while using only a small number of interfaces per node. We address the key problems that arise in the context of such a backhaul architecture, viz., an FSO link design with desired characteristics, and related network design and management problems. We develop and evaluate a robust 100m FSO link prototype, and simulate the proposed architecture in many metro US cities while show its viability via evaluation of key performance metrics.

Conventional static datacenter (DC) network designs offer extreme cost vs. performance tradeoffs---simple leaf-spine networks are cost-effective but oversubscribed, while "fat tree"-like solutions offer good worst-case performance but are expensive. Recent results make a promising case for augmenting an oversubscribed network with reconfigurable inter-rack wireless or optical links. Inspired by the promise of reconfigurability, this paper presents FireFly, an inter-rack network solution that pushes DC network design to the extreme on three key fronts: (1) all links are reconfigurable; (2) all links are wireless; and (3) non top-of-rack switches are eliminated altogether. This vision, if realized, can offer significant benefits in terms of increased flexibility, reduced equipment cost, and minimal cabling complexity. In order to achieve this vision, we need to look beyond traditional RF wireless solutions due to their interference footprint which limits range and data rates. Thus, we make the case for using free-space optics (FSO). We demonstrate the viability of this architecture by (a) building a proof-of-concept prototype of a steerable small form factor FSO device using commodity components and (b) developing practical heuristics to address algorithmic and system-level challenges in network design and management.