EnergyEfficient Decentralized Cooperative Routing in Wireless Networks
(2009) 45th Annual Allerton Conference on Communication, Control and Computing In Ieee Transactions On Automatic Control 54(3). p.512527 Abstract
 Wireless adhoc networks transmit information from a source to a destination via multiple hops in order to save energy and, thus, increase the lifetime of batteryoperated nodes. The energy savings can be especially significant in cooperative transmission schemes, where several nodes cooperate during one hop to forward the information to the next node along a route to the destination. Finding the best multihop transmission policy in such a network which determines nodes that are involved in each hop, is a very important problem, but also a very difficult one especially when the physical wireless channel behavior is to be accounted for and exploited. We model the above optimization problem for randomly fading channels as a decentralized... (More)
 Wireless adhoc networks transmit information from a source to a destination via multiple hops in order to save energy and, thus, increase the lifetime of batteryoperated nodes. The energy savings can be especially significant in cooperative transmission schemes, where several nodes cooperate during one hop to forward the information to the next node along a route to the destination. Finding the best multihop transmission policy in such a network which determines nodes that are involved in each hop, is a very important problem, but also a very difficult one especially when the physical wireless channel behavior is to be accounted for and exploited. We model the above optimization problem for randomly fading channels as a decentralized control problem  the channel observations available at each node define the information structure, while the control policy is defined by the power and phase of the signal transmitted by each node. In particular, we consider the problem of computing an energyoptimal cooperative transmission scheme in a wireless network for two different channel fading models: (i) slow fading channels, where the channel gains of the links remain the same for a large number of transmissions, and (ii) fast fading channels, where the channel gains of the links change quickly from one transmission to another. For slow fading, we consider a factored class of policies (corresponding to local cooperation between nodes), and show that the computation of an optimal policy in this class is equivalent to a shortest path computation on an induced graph, whose edge costs can be computed in a decentralized manner using only locally available channel state information (CSI). For fast fading, both CSI acquisition and data transmission consume energy. Hence, we need to jointly optimize over both these; we cast this optimization problem as a large stochastic optimization problem. We then jointly optimize over a set of CSI functions of the local channel states, and a corresponding factored class of control policies corresponding to local cooperation between nodes with a local outage constraint. The resulting optimal scheme in this class can again be computed efficiently in a decentralized manner. We demonstrate significant energy savings for both slow and fast fading channels through numerical simulations of randomly distributed networks. (Less)
Please use this url to cite or link to this publication:
http://lup.lub.lu.se/record/1401851
 author
 Madan, Ritesh; Mehta, Neelesh B.; Molisch, Andreas ^{LU} and Zhang, Jin
 organization
 publishing date
 2009
 type
 Chapter in Book/Report/Conference proceeding
 publication status
 published
 subject
 keywords
 multiple output (MIMO) systems, multiple input, Ad hoc networks, channel state information (CSI)
 in
 Ieee Transactions On Automatic Control
 volume
 54
 issue
 3
 pages
 512  527
 publisher
 IEEEInstitute of Electrical and Electronics Engineers Inc.
 conference name
 45th Annual Allerton Conference on Communication, Control and Computing
 external identifiers

 wos:000264397200008
 scopus:63449103477
 ISSN
 00189286
 DOI
 10.1109/TAC.2009.2012979
 language
 English
 LU publication?
 yes
 id
 4264a745116d49c0bf3713df6490bb1a (old id 1401851)
 date added to LUP
 20090615 09:42:53
 date last changed
 20171001 04:30:41
@inproceedings{4264a745116d49c0bf3713df6490bb1a, abstract = {Wireless adhoc networks transmit information from a source to a destination via multiple hops in order to save energy and, thus, increase the lifetime of batteryoperated nodes. The energy savings can be especially significant in cooperative transmission schemes, where several nodes cooperate during one hop to forward the information to the next node along a route to the destination. Finding the best multihop transmission policy in such a network which determines nodes that are involved in each hop, is a very important problem, but also a very difficult one especially when the physical wireless channel behavior is to be accounted for and exploited. We model the above optimization problem for randomly fading channels as a decentralized control problem  the channel observations available at each node define the information structure, while the control policy is defined by the power and phase of the signal transmitted by each node. In particular, we consider the problem of computing an energyoptimal cooperative transmission scheme in a wireless network for two different channel fading models: (i) slow fading channels, where the channel gains of the links remain the same for a large number of transmissions, and (ii) fast fading channels, where the channel gains of the links change quickly from one transmission to another. For slow fading, we consider a factored class of policies (corresponding to local cooperation between nodes), and show that the computation of an optimal policy in this class is equivalent to a shortest path computation on an induced graph, whose edge costs can be computed in a decentralized manner using only locally available channel state information (CSI). For fast fading, both CSI acquisition and data transmission consume energy. Hence, we need to jointly optimize over both these; we cast this optimization problem as a large stochastic optimization problem. We then jointly optimize over a set of CSI functions of the local channel states, and a corresponding factored class of control policies corresponding to local cooperation between nodes with a local outage constraint. The resulting optimal scheme in this class can again be computed efficiently in a decentralized manner. We demonstrate significant energy savings for both slow and fast fading channels through numerical simulations of randomly distributed networks.}, author = {Madan, Ritesh and Mehta, Neelesh B. and Molisch, Andreas and Zhang, Jin}, booktitle = {Ieee Transactions On Automatic Control}, issn = {00189286}, keyword = {multiple output (MIMO) systems,multiple input,Ad hoc networks,channel state information (CSI)}, language = {eng}, number = {3}, pages = {512527}, publisher = {IEEEInstitute of Electrical and Electronics Engineers Inc.}, title = {EnergyEfficient Decentralized Cooperative Routing in Wireless Networks}, url = {http://dx.doi.org/10.1109/TAC.2009.2012979}, volume = {54}, year = {2009}, }