Conference Paper

On Spatial Reuse and Capture in Ad Hoc Networks

Univ. of South Carolina, Columbia
DOI: 10.1109/WCNC.2008.291 Conference: Wireless Communications and Networking Conference, 2008. WCNC 2008. IEEE
Source: IEEE Xplore

ABSTRACT Neighbors of both the transmitter and the receiver must keep quiet in a 802.11 wireless network as it requires bidirectional exchange, i.e., nodes reverse their roles as transmitters and receivers, for transmitting a single DATA frame. To reduce role reversals and to improve spatial reuse, a piggybacked acknowledgment based approach has been proposed to enable concurrent transmissions. Recent findings on physical layer capture show that it is possible to capture a frame of interest in the presence of concurrent interference and that the SINR threshold is dependent on the relative order in which the frame and the interference arrive at the receiver. In this paper, we show that it is possible to exploit capture and increase concurrent transmissions in wireless adhoc networks. We develop a distributed channel access scheme and demonstrate that it offers significant throughput gain particularly at lower data rates.

  • [Show abstract] [Hide abstract]
    ABSTRACT: With a view to conserve energy, a basic power control (BPC) scheme was suggested in distributed control IEEE 802.11 wireless ad hoc networks, where a data frame is sent at the lowest permitted power. Past research showed that BPC works inefficiently in terms of throughput as well as energy consumption. In this paper we revisit the effects of BPC on the network performance with the nodes having frame arrival order dependent signal capture (ODC) capability. We first analyze the reasons for poor performance of basic power control without ODC. We then investigate the effect of ODC on system throughput as well as energy efficiency. Via intuitive arguments and network simulations we demonstrate that, in presence of ODC capability of the receivers, BPC can be highly effective in terms of throughput as well as energy efficiency.
    Communications (NCC), 2013 National Conference on; 01/2013
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Numerous studies have shown that concurrent transmissions can help to boost wireless network performance despite the possibility of packet collisions. However, while these works provide empirical evidence that concurrent transmissions may be received reliably, existing signal capture models only partially explain the root causes of this phenomenon. We present a comprehensive mathematical model for MSK-modulated signals that makes the reasons explicit and thus provides fundamental insights on the key parameters governing the successful reception of colliding transmissions. A major contribution is the closed-form derivation of the receiver bit decision variable for an arbitrary number of colliding signals and constellations of power ratios, time offsets, and carrier phase offsets. We systematically explore the factors for successful packet delivery under concurrent transmissions across the whole parameter space of the model. We confirm the capture threshold behavior observed in previous studies but also reveal new insights relevant to the design of optimal protocols: We identify capture zones depending not only on the signal power ratio but also on time and phase offsets.
    IEEE Transactions on Wireless Communications 08/2014; · 2.42 Impact Factor
  • Source
    Proceedings of the 2014 ACM Conference on Security and Privacy in Wireless & Mobile Networks, Oxford, United Kingdom; 01/2014


Available from