Optimal physical carrier sensing to defend against exposed terminal problem in wireless ad hoc networks

Physical carrier sensing (PCS) is an effective mechanism to reduce the collision and interference caused by hidden terminals in wireless ad hoc networks, which allows nodes to be separated by a silent margin. However, potential simultaneous transmissions may be suppressed in this silent margin due to exposed terminal problem. As a consequence, PCS mechanism affects the network performance in two opposite ways. In this paper, we present an analytical model for deriving the optimal carrier sensing threshold to make a tradeoff between hidden terminal and exposed terminal problems for given network topology. Our model takes into account the potential throughput loss of exposed terminals, which previous studies have ignored. Based on the model, an adaptive and iterative algorithm is proposed to obtain the optimal sensing threshold and dynamically adjust the physical carrier sensing threshold through periodic estimation of channel condition. Simulation results demonstrate that the proposed scheme outperforms IEEE 802.11 protocol in terms of average network throughput.

[1]  Fu-Yi Hung,et al.  Effectiveness of Physical and Virtual Carrier Sensing in IEEE 802.11 Wireless Ad Hoc Networks , 2007, 2007 IEEE Wireless Communications and Networking Conference.

[2]  Chun-cheng Chen,et al.  SELECT: Self-Learning Collision Avoidance for Wireless Networks , 2008, IEEE Transactions on Mobile Computing.

[3]  Sylvie Perreau,et al.  Hidden vs . Exposed Terminal Problem in Ad hoc Networks , .

[4]  Micah Z. Brodsky,et al.  In defense of wireless carrier sense , 2009, SIGCOMM '09.

[5]  Yong Yang,et al.  Modeling the Effect of Transmit Power and Physical Carrier Sense in Multi-Hop Wireless Networks , 2007, IEEE INFOCOM 2007 - 26th IEEE International Conference on Computer Communications.

[6]  A. Girotra,et al.  Performance Analysis of the IEEE 802 . 11 Distributed Coordination Function , 2005 .

[7]  Xinming Zhang,et al.  Coordinated dynamic physical carrier sensing based on local optimization in wireless ad hoc networks , 2013, 2013 IEEE Wireless Communications and Networking Conference (WCNC).

[8]  Jing Zhu,et al.  Adapting physical carrier sensing to maximize spatial reuse in 802.11 mesh networks , 2004, Wirel. Commun. Mob. Comput..

[9]  Jing Zhu,et al.  Optimizing 802.11 Wireless Mesh Networks Based on Physical Carrier Sensing , 2009, IEEE/ACM Transactions on Networking.

[10]  Chin-Tau A. Lea,et al.  Fairness Enhancement for 802.11 MAC , 2009, AccessNets.

[11]  Nitin H. Vaidya,et al.  On physical carrier sensing in wireless ad hoc networks , 2005, Proceedings IEEE 24th Annual Joint Conference of the IEEE Computer and Communications Societies..

[12]  Liqun Fu,et al.  Effective Carrier Sensing in CSMA Networks under Cumulative Interference , 2010, 2010 Proceedings IEEE INFOCOM.

[13]  Chadi Assi,et al.  A Spatiotemporal Contention Resolution for Enhancing Spatial Reuse in Wireless Networks , 2011, IEEE Transactions on Vehicular Technology.