Mirror mirror on the ceiling

Abstract

Modern data centers are massive, and support a range of distributed applications across potentially hundreds of server racks. As their utilization and bandwidth needs continue to grow, traditional methods of augmenting bandwidth have proven complex and costly in time and resources. Recent measurements show that data center traffic is often limited by congestion loss caused by short traffic bursts. Thus an attractive alternative to adding physical bandwidth is to augment wired links with wireless links in the 60 GHz band.We address two limitations with current 60 GHz wireless proposals. First, 60 GHz wireless links are limited by line-of-sight, and can be blocked by even small obstacles. Second, even beamforming links leak power, and potential interference will severely limit concurrent transmissions in dense data centers. We propose and evaluate a new wireless primitive for data centers, 3D beamforming, where 60 GHz signals bounce off data center ceilings, thus establishing indirect line-of-sight between any two racks in a data center. We build a small 3D beamforming testbed to demonstrate its ability to address both link blockage and link interference, thus improving link range and number of concurrent transmissions in the data center. In addition, we propose a simple link scheduler and use traffic simulations to show that these 3D links significantly expand wireless capacity compared to their 2D counterparts.

Laser Based Energy Distribution Architecture for Decoupling Energy and Sensing Planes in WSN

“…We believe that adding a third node-type, having mirrors, in our architecture can allow a power beam to route around obstacles. We see this achievable with previous work for outdoor settings on reflecting sunlight [8, 16] and indoors using mirrors on the ceiling as used for a non-LoS 60 Ghz wireless communication in data-center networks [40].…”

60 GHz wireless data center networks: A survey

“…Although 802.15.3c standard is the subject of some papers like [27], most of the studies in literature are based on 802.11ad standard [28][29][30]. Popularity of 802.11ad versus other 60 GHz wireless standards can also be seen from the results of Google Trends data taken between December 2014 and December 2017 [31].…”

“…Like [28,40] proposes a 3D beamforming technique named Graphite to eliminate transmission blocking problems caused by antennas placed at the same-height. However, they did not place reflectors on the ceiling as done in [28]. Instead they suggest using rotatable and liftable crank arms as seen in Fig.…”

An Efficient Wireless Control Plane for Software Defined Networking in Data Center Networks

“…The authors suggested that by using 60 GHz directional links, concurrent multi-Gbps data rates can be achieved. In a similar work [9], the authors also used 60 GHz link with 3D beam forming to reduce interference. In this work, the authors focused on link blockage and link interference problems to increase overall link range and number of concurrent transmissions.…”