Abstract-The 60GHz spectrum gives us the opportunity to deliver gigabit rates to users in a WLAN (Wireless Local Area Network) setting. The constrained propagation of signals at this frequency band ensures limited coverage which in turn enables the construction of very efficient STDMA (Spatial Time Division Multiple Access) schedules. In this paper we study the achievable aggregate capacity in a room when using two types of smart antenna arrays -linear and circular. Using detailed Matlab simulations, we show that with just 400MHz of the spectrum, aggregate data rates of 9Gbps (4.5Gbps) can be achieved with linear (circular) arrays. We also study the energy efficiency of the communication and show that the energy/bit is as low as 0.2 × 10 −10 (0.2 × 10 −9 ) Joules/Bit by using variable transmit powers at different parts of the room. Finally, we study the problem of coverage due to blocking of the LOS (Line Of Sight) path. To mitigate this problem we study the use of static reflectors and show that coverage in the entire room can indeed be maintained.

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In typical enterprise networks, a large fraction of ports see utilization of less than 5% at peak times and close to zero utilization otherwise. Therefore, the normal architecture of one switch port per end-host is very wasteful because of the need for high port density switches to support numerous end users. In this paper we propose merging traffic from multiple end-hosts and feeding that to small port density switches that can replace the high port density switches. The energy savings from such a redesign are significant. The innovative part of this paper is the design of a low-power Merge network that is used to merge traffic from N incoming links to be fed to K switch ports and for sending traffic from the K-port switch to N links. Further, we present algorithms to enable network designers to re-architect their networks using the merge network, and a feasibility study using our College of Engineering network as a working example to illustrate how this approach would work and the resultant energy savings of almost 47%.

Abstract-60GHz is well-suited for device-to-device communication and for general in-home applications due to its huge available bandwidth. However, links at this frequency are easily degraded by environmental conditions. Indeed, the poor multipath makes it necessary to maintain good LoS (Line of Sight) paths between communicating pairs of nodes. In this paper we analyze the problem of link breakage and degradation in point-to-point 60GHz networks. We propose using repeaters to provide alternate paths between communicating nodes when the direct path degrades. The decision on which path to use is driven by the goal of maximizing data rate per connection as well as overall throughput in the network. Using extensive simulations we show that by carefully using repeaters, we can maintain Gbps rates for each pair of communicating nodes in indoor spaces. We develop an efficient distributed algorithm for allocating repeaters to links as needed and explicitly deal with the problem of interference caused by the repeaters themselves. Finally, we study the scalability of the solution with increasing numbers of communicating pairs and show that Gbps rates can be maintained even when there are as many as eight communicating pairs in a small 10mx10m room.

Abstract. Tracking the movement of people in indoor environments is useful for a variety of applications including elderly care, study of shopper behavior in shopping centers, security etc. There have been several previous efforts at solving this problem but with limited success. Our approach uses inexpensive pressure sensors, placed in a specific manner, that allows us to identify multiple people. Given this information, our algorithm can track multiple people across the floor even in the presence of large sensor error. The algorithm we develop is evaluated for a variety of different movement patterns that include turning and path crossing. The error in correct path detection is shown to be very small even in the most complex movement scenario. We note that our algorithm does not use any a priori information such as weight, rfid tags, knowledge of number of people, etc.