Page 1. IEEE/ACM TRANSACTIONS ON NETWORKING, VOL. 18, NO. 3, JUNE 2010 973 Fast Algorithms for Re... more Page 1. IEEE/ACM TRANSACTIONS ON NETWORKING, VOL. 18, NO. 3, JUNE 2010 973 Fast Algorithms for Resource Allocation in Wireless Cellular Networks Ritesh Madan, Stephen P. Boyd, Fellow, IEEE, and Sanjay Lall, Senior Member, IEEE ...
Abstract— We consider sensor networks where,energy is a limited resource so that energy consumpti... more Abstract— We consider sensor networks where,energy is a limited resource so that energy consumption must be minimized while satisfying given throughput requirements. Moreover, energy consumption must take into account both the transmission energy and the circuit processing energy for short-range communications. In this context, we analyze energy-efficient joint routing, scheduling, and link adaptation strategies that maximize the network lifetime. We emphasize that the energy efficiency must be supported across all layers of the protocol stack through a cross-layer design. We start with the joint MAC and link layer optimization, and then extend the model to include routing optimization. The joint optimization minimizes the total energy consumption including both the transmission energy and the circuit processing energy across the network. We propose variable-length TDMA schemes where the slot length is optimally assigned according to the routing requirement while minimizing the energy consumption across the network. We show that the optimization problems can be transformed into or approximated by convex problems that can be efficiently solved using known techniques. The results show that multihop routing schemes are usually more energy-efficient when only transmission energy is considered, but single-hop transmission may be more efficient when,the circuit processing energy is also taken into account. The delay performance of the optimal TDMA scheme is analyzed and an algorithm for minimum-delay scheduling is proposed. The delay analysis result can be applied to general networks based on TDMA transmissions. Index Terms— Energy efficiency, Joint Routing and Schedul-
We consider sensor networks where energy is a limited resource so that energy consumption must be... more We consider sensor networks where energy is a limited resource so that energy consumption must be minimized while satisfying given throughput requirements. Moreover, energy consumption must take into account both the transmission energy and the circuit processing energy for short-range communications. In this context, we analyze the energy-efficient joint routing, scheduling, and link ad aptation strategies that maximize the network lifetime and we emphasize that the energy efficiency must be supported across all layers of the protocol stack through a cross-layer design. We start with the joint MAC and link layer optimization, and then extend the model to include routing optimization. The joint optimization minimizes the total energy consumption including both the transmission energy and the circuit processing energy across the network. We propose variable-length TDMA schemes where the slot length is optimally assigned according to the routing r equirement while keeping the total energy consumption minimized. We show that the optimization problems can be transformed into or approximated by convex problems that can be efficiently solved using known techniques. The re sults show that multihop routing schemes are more energy-efficient when only transmission energy is concerne d, but single-hop transmissions may be more efficient when the circuit processing energy is considered. Index Terms Energy efficiency, Joint Routing and Scheduling, Link Adapt ation, Cross-layer. I. I NTRODUCTION
We consider sensor networks in which individual nodes with on-board sensing and low-power transmi... more We consider sensor networks in which individual nodes with on-board sensing and low-power transmitters and receivers establish connections with neighboring nodes. The overall objective is to enable energy-efficient data communication, relayed between arbitrary nodes on the network. We develop a distributed algorithm which minimizes the power required for neighbor discovery. Initially nodes do not have deterministic knowledge of the location of their neighbors, and we model the distribution of the nodes as a two-dimensional Poisson process with known intensity. This corresponds to a situation in which a large number of nodes are randomly distributed over a given area. The process of neighbor discovery is modeled as a Markov decision process, and the resulting control policy is a finite automaton, driven by the underlying probability distribution, that minimizes the average power consumed. This policy can be computed offline and stored in each node with very low requirements for online memory and processor capability.
We consider the problem of finding an optimal feedback controller for a network of interconnected... more We consider the problem of finding an optimal feedback controller for a network of interconnected subsystems, each of which is a Markov decision process. Each subsys-tem is coupled to its neighbors via communication links by which signals are delayed but are otherwise transmit-ted ...
IEEE Transactions on Wireless Communications, 2006
Abstract A sensor network of nodes with wireless trans-ceiver capabilities and limited energy is... more Abstract A sensor network of nodes with wireless trans-ceiver capabilities and limited energy is considered. We propose distributed algorithms to compute an optimal routing scheme that maximizes the time at which the first node in the network drains out of energy. The ...
Abstract A sensor network of nodes with wireless trans-ceiver capabilities and limited energy is... more Abstract A sensor network of nodes with wireless trans-ceiver capabilities and limited energy is considered. We propose distributed algorithms to compute an optimal routing scheme that maximizes the time at which the first node in the network drains out of energy. The ...
We consider a broad class of interference coordination and resource allocation problems for wirel... more We consider a broad class of interference coordination and resource allocation problems for wireless links where the goal is to maximize the sum of functions of individual link rates. Such problems arise in the context of, for example, fractional frequency reuse (FFR) for macro-cellular networks and dynamic interference management in femtocells. The resulting optimization problems are typically hard to solve optimally even using centralized algorithms but are an essential computational step in implementing rate-fair and queue stabilizing scheduling policies in wireless networks. We consider a belief propagation framework to solve such problems approximately. In particular, we construct approximations to the belief propagation iterations to obtain computationally simple and distributed algorithms with low communication overhead. Notably, our methods are very general and apply to, for example, the optimization of transmit powers, transmit beamforming vectors, and sub-band allocation to maximize the above objective. Numerical results for femtocell deployments demonstrate that such algorithms compute a very good operating point in typically just a couple of iterations.
IEEE Journal on Selected Areas in Communications, 2010
Embedding pico/femto base-stations and relay nodes in a macro-cellular network is a promising met... more Embedding pico/femto base-stations and relay nodes in a macro-cellular network is a promising method for achieving substantial gains in coverage and capacity compared to macro-only networks. These new types of base-stations can operate on the same wireless channel as the macro-cellular network, providing higher spatial reuse via cell splitting. However, these base-stations are deployed in an unplanned manner, can have very different transmit powers, and may not have traffic aggregation among many users. This could potentially result in much higher interference magnitude and variability. Hence, such deployments require the use of innovative cell association and inter-cell interference coordination techniques in order to realize the promised capacity and coverage gains. In this paper, we describe new paradigms for design and operation of such heterogeneous cellular networks. Specifically, we focus on cell splitting, range expansion, semi-static resource negotiation on third-party backhaul connections, and fast dynamic interference management for QoS via over-the-air signaling. Notably, our methodologies and algorithms are simple, lightweight, and incur extremely low overhead. Numerical studies show that they provide large gains over currently used methods for cellular networks.
Page 1. IEEE/ACM TRANSACTIONS ON NETWORKING, VOL. 18, NO. 3, JUNE 2010 973 Fast Algorithms for Re... more Page 1. IEEE/ACM TRANSACTIONS ON NETWORKING, VOL. 18, NO. 3, JUNE 2010 973 Fast Algorithms for Resource Allocation in Wireless Cellular Networks Ritesh Madan, Stephen P. Boyd, Fellow, IEEE, and Sanjay Lall, Senior Member, IEEE ...
Abstract— We consider sensor networks where,energy is a limited resource so that energy consumpti... more Abstract— We consider sensor networks where,energy is a limited resource so that energy consumption must be minimized while satisfying given throughput requirements. Moreover, energy consumption must take into account both the transmission energy and the circuit processing energy for short-range communications. In this context, we analyze energy-efficient joint routing, scheduling, and link adaptation strategies that maximize the network lifetime. We emphasize that the energy efficiency must be supported across all layers of the protocol stack through a cross-layer design. We start with the joint MAC and link layer optimization, and then extend the model to include routing optimization. The joint optimization minimizes the total energy consumption including both the transmission energy and the circuit processing energy across the network. We propose variable-length TDMA schemes where the slot length is optimally assigned according to the routing requirement while minimizing the energy consumption across the network. We show that the optimization problems can be transformed into or approximated by convex problems that can be efficiently solved using known techniques. The results show that multihop routing schemes are usually more energy-efficient when only transmission energy is considered, but single-hop transmission may be more efficient when,the circuit processing energy is also taken into account. The delay performance of the optimal TDMA scheme is analyzed and an algorithm for minimum-delay scheduling is proposed. The delay analysis result can be applied to general networks based on TDMA transmissions. Index Terms— Energy efficiency, Joint Routing and Schedul-
We consider sensor networks where energy is a limited resource so that energy consumption must be... more We consider sensor networks where energy is a limited resource so that energy consumption must be minimized while satisfying given throughput requirements. Moreover, energy consumption must take into account both the transmission energy and the circuit processing energy for short-range communications. In this context, we analyze the energy-efficient joint routing, scheduling, and link ad aptation strategies that maximize the network lifetime and we emphasize that the energy efficiency must be supported across all layers of the protocol stack through a cross-layer design. We start with the joint MAC and link layer optimization, and then extend the model to include routing optimization. The joint optimization minimizes the total energy consumption including both the transmission energy and the circuit processing energy across the network. We propose variable-length TDMA schemes where the slot length is optimally assigned according to the routing r equirement while keeping the total energy consumption minimized. We show that the optimization problems can be transformed into or approximated by convex problems that can be efficiently solved using known techniques. The re sults show that multihop routing schemes are more energy-efficient when only transmission energy is concerne d, but single-hop transmissions may be more efficient when the circuit processing energy is considered. Index Terms Energy efficiency, Joint Routing and Scheduling, Link Adapt ation, Cross-layer. I. I NTRODUCTION
We consider sensor networks in which individual nodes with on-board sensing and low-power transmi... more We consider sensor networks in which individual nodes with on-board sensing and low-power transmitters and receivers establish connections with neighboring nodes. The overall objective is to enable energy-efficient data communication, relayed between arbitrary nodes on the network. We develop a distributed algorithm which minimizes the power required for neighbor discovery. Initially nodes do not have deterministic knowledge of the location of their neighbors, and we model the distribution of the nodes as a two-dimensional Poisson process with known intensity. This corresponds to a situation in which a large number of nodes are randomly distributed over a given area. The process of neighbor discovery is modeled as a Markov decision process, and the resulting control policy is a finite automaton, driven by the underlying probability distribution, that minimizes the average power consumed. This policy can be computed offline and stored in each node with very low requirements for online memory and processor capability.
We consider the problem of finding an optimal feedback controller for a network of interconnected... more We consider the problem of finding an optimal feedback controller for a network of interconnected subsystems, each of which is a Markov decision process. Each subsys-tem is coupled to its neighbors via communication links by which signals are delayed but are otherwise transmit-ted ...
IEEE Transactions on Wireless Communications, 2006
Abstract A sensor network of nodes with wireless trans-ceiver capabilities and limited energy is... more Abstract A sensor network of nodes with wireless trans-ceiver capabilities and limited energy is considered. We propose distributed algorithms to compute an optimal routing scheme that maximizes the time at which the first node in the network drains out of energy. The ...
Abstract A sensor network of nodes with wireless trans-ceiver capabilities and limited energy is... more Abstract A sensor network of nodes with wireless trans-ceiver capabilities and limited energy is considered. We propose distributed algorithms to compute an optimal routing scheme that maximizes the time at which the first node in the network drains out of energy. The ...
We consider a broad class of interference coordination and resource allocation problems for wirel... more We consider a broad class of interference coordination and resource allocation problems for wireless links where the goal is to maximize the sum of functions of individual link rates. Such problems arise in the context of, for example, fractional frequency reuse (FFR) for macro-cellular networks and dynamic interference management in femtocells. The resulting optimization problems are typically hard to solve optimally even using centralized algorithms but are an essential computational step in implementing rate-fair and queue stabilizing scheduling policies in wireless networks. We consider a belief propagation framework to solve such problems approximately. In particular, we construct approximations to the belief propagation iterations to obtain computationally simple and distributed algorithms with low communication overhead. Notably, our methods are very general and apply to, for example, the optimization of transmit powers, transmit beamforming vectors, and sub-band allocation to maximize the above objective. Numerical results for femtocell deployments demonstrate that such algorithms compute a very good operating point in typically just a couple of iterations.
IEEE Journal on Selected Areas in Communications, 2010
Embedding pico/femto base-stations and relay nodes in a macro-cellular network is a promising met... more Embedding pico/femto base-stations and relay nodes in a macro-cellular network is a promising method for achieving substantial gains in coverage and capacity compared to macro-only networks. These new types of base-stations can operate on the same wireless channel as the macro-cellular network, providing higher spatial reuse via cell splitting. However, these base-stations are deployed in an unplanned manner, can have very different transmit powers, and may not have traffic aggregation among many users. This could potentially result in much higher interference magnitude and variability. Hence, such deployments require the use of innovative cell association and inter-cell interference coordination techniques in order to realize the promised capacity and coverage gains. In this paper, we describe new paradigms for design and operation of such heterogeneous cellular networks. Specifically, we focus on cell splitting, range expansion, semi-static resource negotiation on third-party backhaul connections, and fast dynamic interference management for QoS via over-the-air signaling. Notably, our methodologies and algorithms are simple, lightweight, and incur extremely low overhead. Numerical studies show that they provide large gains over currently used methods for cellular networks.
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