On adaptive transmission for energy efficiency in wireless data networks

This paper investigates the problem of energy-efficient transmission of data packets in a wireless network by jointly adapting to backlog and channel condition. Specifically, we consider minimum-energy scheduling problems over multiple-access channels, broadcast channels, and channels with fading, when packets of all users need to be transmitted before a deadline T. Earlier work has considered a similar setup and demonstrated significant transmission energy saving by adapting to backlog for channels that are time invariant and when transmission is restricted to time-division. For concreteness, throughout the paper, rates and powers corresponding to optimal coding over discrete-time additive white Gaussian noise (AWGN) channels are assumed. The results, however, hold for more general channels and coding schemes where the total transmitted power is convex in the transmission rates. The offline scheduling problems for all the channels considered are shown to reduce to convex optimization problems with linear constraints. An iterative algorithm, referred to as FlowRight, that finds optimal offline schedules is presented. A heuristic online algorithm that we call look-ahead water-filling, which jointly adapts to both channel fading state and backlog is described. By the use of a small buffer which introduces an almost fixed delay, this algorithm achieves a considerable reduction in energy relative to water filling solely on channel states.

[1]  Shlomo Shamai,et al.  Fading Channels: Information-Theoretic and Communication Aspects , 1998, IEEE Trans. Inf. Theory.

[2]  Rene L. Cruz,et al.  Transmission Policies for Time Varying Channels with Average Delay Constraints , 1999 .

[3]  Elif Uysal-Biyikoglu,et al.  Energy-efficient transmission over a wireless link via lazy packet scheduling , 2001, Proceedings IEEE INFOCOM 2001. Conference on Computer Communications. Twentieth Annual Joint Conference of the IEEE Computer and Communications Society (Cat. No.01CH37213).

[4]  Andrea Goldsmith,et al.  The capacity of downlink fading channels with variable rate and power , 1997 .

[5]  W. S. Yoon,et al.  Delay-optimal power control for wireless data users with average power constraints , 2002, Proceedings IEEE International Symposium on Information Theory,.

[6]  Kjell Jørgen Hole,et al.  Adaptive multidimensional coded modulation over flat fading channels , 2000, IEEE Journal on Selected Areas in Communications.

[7]  Andrea J. Goldsmith,et al.  Capacity of time-slotted ALOHA packetized multiple-access systems over the AWGN channel , 2004, IEEE Transactions on Wireless Communications.

[8]  E. Uysal-Biyikoglu,et al.  Energy-efficient packet transmission over a multiaccess channel , 2002, Proceedings IEEE International Symposium on Information Theory,.

[9]  Randall Berry,et al.  Power and delay trade-offs in fading channels , 2000 .

[10]  Andrea J. Goldsmith,et al.  Variable-rate variable-power MQAM for fading channels , 1997, IEEE Trans. Commun..

[11]  David Tse,et al.  Multiaccess Fading Channels-Part II: Delay-Limited Capacities , 1998, IEEE Trans. Inf. Theory.

[12]  Vikram Srinivasan,et al.  Delay constrained energy efficient transmission strategies for wireless devices , 2002, Proceedings.Twenty-First Annual Joint Conference of the IEEE Computer and Communications Societies.

[13]  Baris Ata,et al.  Dynamic Power Control in a Wireless Static Channel Subject to a Quality-of-Service Constraint , 2005, Oper. Res..

[14]  Dimitri P. Bertsekas,et al.  Nonlinear Programming , 1997 .

[15]  David Tse,et al.  Multiaccess Fading Channels-Part I: Polymatroid Structure, Optimal Resource Allocation and Throughput Capacities , 1998, IEEE Trans. Inf. Theory.

[16]  Elif Uysal-Biyikoglu,et al.  Energy-efficient scheduling of packet transmissions over wireless networks , 2002, Proceedings.Twenty-First Annual Joint Conference of the IEEE Computer and Communications Societies.

[17]  Elif Uysal-Biyikoglu,et al.  Energy-efficient packet transmission over a wireless link , 2002, TNET.

[18]  Axthonv G. Oettinger,et al.  IEEE Transactions on Information Theory , 1998 .

[19]  Thomas M. Cover,et al.  Elements of Information Theory , 2005 .

[20]  Raymond Knopp,et al.  Information capacity and power control in single-cell multiuser communications , 1995, Proceedings IEEE International Conference on Communications ICC '95.

[21]  Eytan Modiano,et al.  Optimal energy allocation and admission control for communications satellites , 2002, Proceedings.Twenty-First Annual Joint Conference of the IEEE Computer and Communications Societies.

[22]  Eytan Modiano,et al.  Power and server allocation in a multi-beam satellite with time varying channels , 2002, Proceedings.Twenty-First Annual Joint Conference of the IEEE Computer and Communications Societies.

[23]  Randall A. Berry,et al.  Buffer control for communication over fading channels , 2000, 2000 IEEE International Symposium on Information Theory (Cat. No.00CH37060).

[24]  Robert G. Gallager,et al.  Discrete Stochastic Processes , 1995 .