Sundar Subramanian

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Recent deployments of data-rich smart phones has provided a fresh impetus for designing, deploying and understanding the performance of wide area ad-hoc networks. The most popular medium access mechanism for such ad hoc networks is CSMA/CA with RTS/CTS. In this paper, using tools from stochastic geometry, we study and optimize the throughput performance of(More)
Geographic forwarding has been widely studied as a routing strategy for large wireless networks, mainly due to the low complexity of the routing algorithm, scalability of the routing information with network size and fast convergence times of routes. On a planar network with no holes, Gupta and Kumar (2000) have shown that a uniform traffic demand of(More)
Geographic routing with greedy relaying strategies have been widely studied as a routing scheme in sensor networks. These schemes assume that the nodes have perfect information about the location of the destination. When the distance between the source and destination is normalized to unity, the asymptotic routing delays in these schemes are(More)
We consider the problem of throughput-optimal routing over large-scale wireless ad-hoc networks. Gupta and Kumar (2000) showed that a throughput capacity (a uniform rate over all source-destination pairs) of thetas( 1/radicn log n ) is achievable in random planar networks, and the capacity is achieved by straight-line routes. In reality, both the network(More)
The IEEE 802.11p standard specifies the PHY and MAC layer operations for transmitting and receiving periodic broadcast messages for vehicular safety. Many studies have identified issues with the CSMA based IEEE 802.11p MAC at high densities of devices, mainly reflected by low packet reception rate. In this paper, we make an interesting observation that with(More)
Millimeter-wave (mmW) multi-input multi-output (MIMO) systems have gained increasing traction toward the goal of meeting the high data-rate requirements in next-generation wireless systems. The focus of this work is on low-complexity beamforming approaches for initial user equipment (UE) discovery in such systems. Toward this goal, we first note the(More)
Interference alignment is known to be degrees of freedom optimal for the K-user interference channel. As a result, many alignment-based schemes have been developed in literature. However, most schemes are not easy to implement due to the requirements for a large number of dimensions and an extensive exchange of channel state information. This paper(More)
The focus of this paper is on beamforming in a millimeter-wave (mmW) multi-input multi-output (MIMO) setup that has gained increasing traction in meeting the high data-rate requirements of next-generation wireless systems. For a given MIMO channel matrix, the optimality of beamforming with the dominant right-singular vector (RSV) at the transmit end and(More)