Tim Holliday

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This paper presents new distributed power and admission control algorithms for ad-hoc wireless networks in random channel environments. Previous work in this area has focused on distributed control for ad-hoc networks with fixed channels. We show that the algorithms resulting from such formulations do not accurately capture the dynamics of a time-varying(More)
This paper presents a new distributed power control algorithm for ad-hoc wireless networks in random channel environments. Previous work in this area has focused on distributed power control for ad-hoc networks with fixed channels. We show that the algorithms resulting from such formulations do not accurately capture the dynamics of a time-varying channel.(More)
A novel dynamic programming formulation is proposed for computing optimal power control, source coding, and channel coding policies when the source traffic has tight delay constraints. Our solution minimizes power consumption subject to constraints on delay for all channel gains. This provides a much tighter delay bound than an average delay constraint,(More)
The finite-state Markov channel (FSMC) is a time-varying channel having states that are characterized by a finite-state Markov chain. These channels have infinite memory, which complicates their capacity analysis. We develop a new method to characterize the capacity of these channels based on Lyapunov exponents. Specifically, we show that the input, output,(More)
A significant amount of recent research has focused on characterizing the diversity-multiplexing tradeoff region in multiple antenna wireless systems. In this paper we focus on finding the point on this diversity-multiplexing region that minimizes an end-to-end distortion measure. Our goal is to find the optimal balance between the increased data rate(More)
A framework is developed for optimizing the tradeoff between diversity, multiplexing, and delay in multiple-input multiple-output (MIMO) systems to minimize end-to-end distortion. The goal is to find the optimal balance between the increased data rate provided by antenna multiplexing, the reduction in transmission errors provided by antenna diversity and(More)
We present an optimal power and rate control policy for delay constrained traffic in next generation TDMA wireless systems. Our solution minimizes average transmit power while satisfying a constraint on the distribution of packets lost to deadline expiration. We also provide a means to account for erroneous and delayed channel estimates. Our results show(More)
A substantial amount of research has focused on analyzing and achieving the diversity-multiplexing tradeoff in multiple antenna (MIMO) wireless communications. Recently, ARQ protocols have been added to these formulations and shown to perform as a type of diversity. Our goal in this paper is to find the optimal operating point in the(More)
We develop a general framework for optimizing link adaptation for multiuser CDMA systems in the wideband limit. The framework is then used to solve for the optimal power control policy that minimizes average transmit power while satisfying a constraint on the per-user probability of packet loss due to deadline expiration. The optimal link adaptation is(More)