Results 1 - 10
of
88
Span: An energy-efficient coordination algorithm for topology maintenance in ad hoc wireless networks
- ACM Wireless Networks Journal
, 2001
"... ..."
(Show Context)
Power-Aware Routing in Mobile Ad Hoc Networks
, 1998
"... In this paper we present a case for using new power-aware metrics for determining routes in wireless ad hoc networks. We present five different metrics based on battery power consumption at nodes. We show that using these metrics in a shortest-cost routing algorithm reduces the cost/packet of rout ..."
Abstract
-
Cited by 775 (5 self)
- Add to MetaCart
In this paper we present a case for using new power-aware metrics for determining routes in wireless ad hoc networks. We present five different metrics based on battery power consumption at nodes. We show that using these metrics in a shortest-cost routing algorithm reduces the cost/packet of routing packets by 5-30% over shortest-hop routing (this cost reduction is on top of a 40-70% reduction in energy consumption obtained by using PAMAS, our MAC layer protocol). Furthermore, using these new metrics ensures that the mean time to node failure is increased significantly. An interesting property of using shortest-cost routing is that packet delays do not increase. Finally, we note that our new metrics can be used in most traditional routing protocols for ad hoc networks. 1
PAMAS -- Power Aware Multi-Access protocol with Signalling for Ad Hoc Networks
, 1998
"... In this paper we develop a new multiaccess protocol for ad hoc radio networks. The protocol is based on the original MACA protocol with the adition of a separate signalling channel. The unique feature of our protocol is that it conserves battery power at nodes by intelligently powering off nodes t ..."
Abstract
-
Cited by 467 (8 self)
- Add to MetaCart
(Show Context)
In this paper we develop a new multiaccess protocol for ad hoc radio networks. The protocol is based on the original MACA protocol with the adition of a separate signalling channel. The unique feature of our protocol is that it conserves battery power at nodes by intelligently powering off nodes that are not actively transmitting or receiving packets. The manner in which nodes power themselves off does not influence the delay or throughput characteristics of our protocol. We illustrate the power conserving behavior of PAMAS via extensive simulations performed over ad hoc networks containing 10-20 nodes. Our results indicate that power savings of between 10 % and 70 % are attainable in most systems. Finally, we discuss how the idea of power awareness can be built into other multiaccess protocols as well.
Vertical Handoffs in Wireless Overlay Networks
, 1996
"... We present extensions to a traditional cellular [Ses95] handoff system to handle the simultaneous operation of multiple wireless network interfaces. This new system allows mobile users to roam in a "Wireless Overlay Network" structure consisting of room-size, building-size, and wide-area d ..."
Abstract
-
Cited by 252 (4 self)
- Add to MetaCart
(Show Context)
We present extensions to a traditional cellular [Ses95] handoff system to handle the simultaneous operation of multiple wireless network interfaces. This new system allows mobile users to roam in a "Wireless Overlay Network" structure consisting of room-size, building-size, and wide-area data networks. In this structure, the user can connect to the wired network through multiple wireless subnets, and offers the best possible connectivity given the user's geographic location and local wireless connectivity. We present the basic handoff system and show that the handoff latency is bounded by the amount of time that the mobile host takes to discover that it has moved in or out of a new wireless overlay. To efficiently support applications that can not tolerate these disruptions, we present optimizations to this basic scheme that assume no knowledge about specific channel characteristics. For handoffs between room-size and building-size overlays, these optimizations lead to a handoff latenc...
Power Management Techniques for Mobile Communication
, 1998
"... In mobile computing, power is a limited resource. Like other devices, communication devices need to be properly managed to conserve energy. In this paper, we present the design and implementation of an innovative transport level protocol capable of significantly reduc- ing the power usage of the com ..."
Abstract
-
Cited by 156 (3 self)
- Add to MetaCart
In mobile computing, power is a limited resource. Like other devices, communication devices need to be properly managed to conserve energy. In this paper, we present the design and implementation of an innovative transport level protocol capable of significantly reduc- ing the power usage of the communication device. The protocol achieves power savings by selectively choosing short periods of time to suspend communications and shut down the communication device. It manages the important task of queuing data for future delivery during periods of communication suspension, and decides when to restart communication. We also address the tradeoff between reducing power consumption and reducing delay for incoming data.
On-demand Power Management for Ad Hoc Networks
, 2003
"... Battery power is an important resource in ad hoc networks. It has been observed that in ad hoc networks, energy consumption does not reflect the communication activities in the network. Many existing energy conservation protocols based on electing a routing backbone for global connectivity are obliv ..."
Abstract
-
Cited by 154 (7 self)
- Add to MetaCart
Battery power is an important resource in ad hoc networks. It has been observed that in ad hoc networks, energy consumption does not reflect the communication activities in the network. Many existing energy conservation protocols based on electing a routing backbone for global connectivity are oblivious to traffic characteristics. In this paper, we propose an extensible on-demand power management framework for ad hoc networks that adapts to traffic load. Nodes maintain soft-state timers that determine power management transitions. By monitoring routing control messages and data transmission, these timers are set and refreshed on-demand. Nodes that are not involved in data delivery may go to sleep as supported by the MAC protocol. This soft state is aggregated across multiple flows and its maintenance requires no additional out-of-band messages. We implement a prototype of our framework in the ns-2 simulator that uses the IEEE 802.11 MAC protocol. Simulation studies using our scheme with the Dynamic Source Routing protocol show a reduction in energy consumption near 50% when compared to a network without power management under both long-lived CBR traffic and on-off traffic loads, with comparable throughput and latency. Preliminary results also show that it outperforms existing routing backbone election approaches.
Application-Driven Power Management for Mobile Communication
, 2000
"... this paper, we present the design and implementation of an innovative transport level protocol capable of significantly reducing the power usage of the communication device. The protocol achieves power savings by selectively choosing short periods of time to suspend communications and shut down th ..."
Abstract
-
Cited by 146 (4 self)
- Add to MetaCart
(Show Context)
this paper, we present the design and implementation of an innovative transport level protocol capable of significantly reducing the power usage of the communication device. The protocol achieves power savings by selectively choosing short periods of time to suspend communications and shut down the communication device. It manages the important task of queuing data for future delivery during periods of communication suspension, and decides when to restart communication. We also address the tradeoff between reducing power consumption and reducing delay for incoming data. We present results from experiments using our implementation of the protocol. These experiments measure the energy consumption for three simulated communication patterns as well as three trace-based communication patterns and compare the effects of different suspension strategies. Our results show up to 83% savings in the energy consumed by the communication. For a high-end laptop, this can translate to 6--9% sav
Data Gathering in Sensor Networks using the Energy*Delay Metric
, 2001
"... In this paper we consider the problem of data collection from a sensor web consisting of N nodes, where nodes have packets of data in each round of communication that need to be gathered and fused with other nodes' packets into one packet and transmitted to a distant base station. Nodes have po ..."
Abstract
-
Cited by 134 (0 self)
- Add to MetaCart
(Show Context)
In this paper we consider the problem of data collection from a sensor web consisting of N nodes, where nodes have packets of data in each round of communication that need to be gathered and fused with other nodes' packets into one packet and transmitted to a distant base station. Nodes have power control in their wireless communications and can transmit directly to any node in the network or to the base station. With unit delay cost for each packet transmission, if all nodes transmit data directly to the base station, then both high energy and high delay per round will occur. In our prior work [6], we developed an algorithm to minimize the energy cost per round, where a linear chain of all the nodes are formed to gather data, and nodes took turns to transmit to the base station. If the goal is to minimize the delay cost, then a binary combining scheme can be used to accomplish this task in about log N units of delay with parallel communications and incurring a slight increase in energy cost. The goal is to find data gathering schemes that balance the energy and delay cost, as measured by energy*delay. We conducted extensive simulation experiments with a number of schemes for this problem with 100 nodes in playing fields of 50m x 50m and 100m x 100m and the base station located at least 100 meters and 200 meters, respectively, from any node. With CDMA capable sensor nodes, a chain-based binary scheme performs best in terms of energy*delay. If the sensor nodes are not CDMA capable, then parallel communications are possible only among spatially separated nodes, and a chain-based 3 level hierarchy scheme performs well. These schemes perform 60 to 100 times better than direct scheme and also outperform a cluster based scheme, called LEACH [3].
MiSer: An Optimal Low-Energy Transmission Strategy for IEEE 802.11 a/h.
, 2003
"... Abstract Reducing the energy consumption by wireless communication devices is perhaps the most important issue in the widely-deployed and exponentially-growing IEEE 802.11 Wireless LANs (WLANs). TPC (Transmit Power Control) and PHY (physical layer) rate adaptation have been recognized as two most e ..."
Abstract
-
Cited by 99 (5 self)
- Add to MetaCart
(Show Context)
Abstract Reducing the energy consumption by wireless communication devices is perhaps the most important issue in the widely-deployed and exponentially-growing IEEE 802.11 Wireless LANs (WLANs). TPC (Transmit Power Control) and PHY (physical layer) rate adaptation have been recognized as two most effective ways to achieve this goal. The emerging 802.11h standard, which is an extension to the current 802.11 MAC and the high-speed 802.11a PHY, will provide a structured means to support intelligent TPC. In this paper, we propose a novel scheme, called MiSer, that minimizes the communication energy consumption in 802.11a/h systems by combining TPC with PHY rate adaptation. The key idea is to compute offline an optimal rate-power combination table, and then at runtime, a wireless station determines the most energyefficient transmission strategy for each data frame by a simple table lookup. Another key contribution of this paper is to provide a rigorous analysis of the relation among different radio ranges and TPC's effect on the interference in 802.11a/h systems, which justifies MiSer's approach to ameliorating the TPC-caused interference by transmitting the CTS frames at a stronger power level. Our simulation results show that MiSer delivers about 20% more data per unit of energy consumption than the PHY rate adaptation scheme without TPC, while outperforming single-rate TPC schemes significantly thanks to the excellent energy-saving capability of PHY rate adaptation.
