Research Article BandEst: Measurement-Based Available Bandwidth Estimation and Flow Admission Control Algorithm for Ad Hoc IEEE 802.15.4-Based Wireless Multimedia Networks Muhammad Omer Farooq 1 and Thomas Kunz 2 1 Institute of Telematics, University of L¨ ubeck, Building 64, 2nd and 3rd Floor, Ratzerburger Allee 160, 23562 L¨ ubeck, Germany 2 Systems and Computer Engineering, Carleton University, 1125 Colonel By Drive, Ottawa, ON, Canada K1S 5B6 Correspondence should be addressed to Muhammad Omer Farooq; farooq@itm.uni-luebeck.de Received 25 June 2014; Revised 5 September 2014; Accepted 19 September 2014 Academic Editor: Chi Zhang Copyright © 2015 M. O. Farooq and T. Kunz. Tis is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. We highlight diferent important factors that must be considered for an efective available-bandwidth-based fow admission control algorithm in ad hoc wireless networks. Moreover, we present BandEst; it is a combination of a measurement-based available bandwidth estimation technique and a fow admission control algorithm for ad hoc IEEE 802.15.4-based ad hoc networks that considers the identifed factors. Extensive simulations are performed to compare BandEst with the state-of-the-art available- bandwidth-based fow admission control algorithms for ad hoc wireless networks. Our simulation results demonstrate that BandEst signifcantly outperforms the state-of-the-art available-bandwidth-based fow admission control algorithms for ad hoc wireless networks. 1. Introduction IEEE 802.15.4-based ad hoc wireless multimedia sensor networks (WMSNs) are starting to emerge [1]. Typically, these networks are deployed for visual surveillance [2] and assisted living [3]. Te bandwidth supported by the IEEE 802.15.4 standard is limited and shared. Limited and shared bandwidth imply that an IEEE 802.15.4-based ad hoc WMSN can only accommodate a few fows inside the network. A large number of fows inside the network (w.r.t. the available resources, e.g., the available bandwidth) can cause congestion. Terefore, a fow admission control algorithm is required that limits the amount of data inside the network. In ad hoc IEEE 802.15.4-based wireless networks, band- width is a shared resource. Te common assumption is that the bandwidth available to a node is shared within the interference range of the node, and nodes within two hops distance can cause interference [4]. We also hold this assumption throughout the paper. Te shared nature of the bandwidth in wireless networks results in the following phenomenon: the data generation rate of nodes within the interference range of a node inside a network afects (i) the available bandwidth [5] and (ii) intra-fow and inter-fow contention [5]. Furthermore, a MAC layer protocol dictates the sharing of a communication medium; hence it limits the amount of bandwidth available to a node, for example, in a carrier sense multiple access collision avoidance (CSMA- CA) MAC layer protocol a node can not transmit in a back- of mode. Terefore, an efective available-bandwidth-based fow admission control algorithm must take into account the identifed factors. Tis paper identifes the following: (i) the contention count on a node which is not along the data forwarding path, but is within the interference range of transmitters along the data forwarding path, is a function of the number of transmitters (along the data forwarding path) within the interference range of the node, (ii) the maximum intra-fow contention count on a node along the data forwarding path is 5 times the fow’s required bandwidth, (iii) increased data trafc inside a network increases the CSMA-CA-based MAC layer overhead, that is, mean back-of interval, mean number of retransmissions, mean ACK waiting time, mean number Hindawi Publishing Corporation International Journal of Distributed Sensor Networks Volume 2015, Article ID 539048, 15 pages http://dx.doi.org/10.1155/2015/539048