TY - JOUR
T1 - Distributed opportunistic scheduling for Ad Hoc networks with random access
T2 - An optimal stopping approach
AU - Zheng, Dong
AU - Ge, Weiyan
AU - Zhang, Junshan
N1 - Funding Information:
Manuscript received August 24, 2007; revised September 09, 2008. The material in this paper was presented in part at MobiHoc, Montréal, QC, Canada, September 2007. This work was supported in part by the U.S. Office of Naval Research under Grant N00014-05-1-0636 and by the National Science Foundation under Grants ANI-0238550 and CNS-0721820. D. Zheng is with the NextWireless, Inc., San Diego, CA 92130 USA. W. Ge is with Qualcomm, Inc., San Diego, CA 92121 USA. J. Zhang is with the Department of Electrical Engineering, Arizona State University, Tempe, AZ 85287 USA (e-mail: junshan.zhang@asu.edu). Color versions of Figures 4–7 and 9 in this paper are available online at http:// ieeexplore.ieee.org. Communicated by P. Viswanath, Associate Editor for Communications. Digital Object Identifier 10.1109/TIT.2008.2008137
PY - 2009
Y1 - 2009
N2 - In this paper, we study distributed opportunistic scheduling (DOS) in an ad hoc network, where many links contend for the same channel using random access. In such a network, DOS involves a process of joint channel probing and distributed scheduling. Due to channel fading, the link condition corresponding to a successful channel probing could be either good or poor. In the latter case, further channel probing, although at the cost of additional delay, may lead to better channel conditions and hence yield higher throughput. The desired tradeoff boils down to judiciously choosing the optimal stopping rule for channel probing and distributed scheduling. In this paper, we pursue a rigorous characterization of the optimal strategies from two perspectives, namely, a network-centric perspective and a user-centric perspective. We first consider DOS from a network-centric point of view, where links cooperate to maximize the overall network throughput. Using optimal stopping theory, we show that the optimal scheme for DOS turns out to be a pure threshold policy, where the rate threshold can be obtained by solving a fixed-point equation. We further devise iterative algorithms for computing the threshold. We also generalize the studies to take into account fairness requirements. Next, we explore DOS from a user-centric perspective, where each link seeks to maximize its own throughput. We treat the problem of threshold selection across different links as a noncooperative game. We explore the existence and uniqueness of the Nash equilibrium, and show that the Nash equilibrium can be approached by the best response strategy. Since the best response strategy requires message passing from neighboring nodes, we then develop an online stochastic iterative algorithm based on local observations only, and establish its convergence to the Nash equilibrium. Because there is an efficiency loss at the Nash equilibrium, we then study pricing-based mechanisms to mitigate the loss. Our results reveal that rich physical layer/MAC layer (PHY/MAC) diversities are available for exploitation in ad hoc networks. We believe that these initial steps open a new avenue for channel-aware distributed scheduling.
AB - In this paper, we study distributed opportunistic scheduling (DOS) in an ad hoc network, where many links contend for the same channel using random access. In such a network, DOS involves a process of joint channel probing and distributed scheduling. Due to channel fading, the link condition corresponding to a successful channel probing could be either good or poor. In the latter case, further channel probing, although at the cost of additional delay, may lead to better channel conditions and hence yield higher throughput. The desired tradeoff boils down to judiciously choosing the optimal stopping rule for channel probing and distributed scheduling. In this paper, we pursue a rigorous characterization of the optimal strategies from two perspectives, namely, a network-centric perspective and a user-centric perspective. We first consider DOS from a network-centric point of view, where links cooperate to maximize the overall network throughput. Using optimal stopping theory, we show that the optimal scheme for DOS turns out to be a pure threshold policy, where the rate threshold can be obtained by solving a fixed-point equation. We further devise iterative algorithms for computing the threshold. We also generalize the studies to take into account fairness requirements. Next, we explore DOS from a user-centric perspective, where each link seeks to maximize its own throughput. We treat the problem of threshold selection across different links as a noncooperative game. We explore the existence and uniqueness of the Nash equilibrium, and show that the Nash equilibrium can be approached by the best response strategy. Since the best response strategy requires message passing from neighboring nodes, we then develop an online stochastic iterative algorithm based on local observations only, and establish its convergence to the Nash equilibrium. Because there is an efficiency loss at the Nash equilibrium, we then study pricing-based mechanisms to mitigate the loss. Our results reveal that rich physical layer/MAC layer (PHY/MAC) diversities are available for exploitation in ad hoc networks. We believe that these initial steps open a new avenue for channel-aware distributed scheduling.
KW - Ad hoc networks
KW - Distributed opportunistic scheduling (DOS)
KW - Game theory
KW - Optimal stopping
KW - Threshold policy
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U2 - 10.1109/TIT.2008.2008137
DO - 10.1109/TIT.2008.2008137
M3 - Article
AN - SCOPUS:58249137672
SN - 0018-9448
VL - 55
SP - 205
EP - 222
JO - IEEE Transactions on Information Theory
JF - IEEE Transactions on Information Theory
IS - 1
ER -