Hindawi Publishing Corporation EURASIP Journal on Wireless Communications and Networking Volume 2007, Article ID 63708, 1 page doi:10.1155/2007/63708 Editorial Wireless Mobile Ad Hoc Networks Hamid R. Sadjadpour, 1 Robert Ulman, 2 Ananthram Swami, 3 and Anthony Ephremides 4 1 School of Engineering, University of California, Santa Cruz, CA 95064, USA 2 Army Research Office, Research Triangle Park, NC 27709, USA 3 Army Research Laboratory, Adelphia, MD 20783, USA 4 Department of Elect rical Engineering, University of Maryland at College Park, MD 20742, USA Received 4 June 2007; Accepted 4 June 2007 Copyright © 2007 Hamid R. Sadjadpour et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, dist ribution, and reproduction in any medium, provided the original work is properly cited. Wireless mobile ad hoc networks (MANETs), due to their dynamic nature and due to the unreliability of the wireless medium, pose unique challenges that are significantly more complex than those that arise in traditional wired or even cellular wireless networks. MANETs must self organize into a multihop peer-to-peer network without centralized con- trol and without the help of base stations. Their topologies are unpredictable due to mobility and due to fading, shad- owing, and other wireless channel impair ments. The num- ber and distr ibution of active n odes in the network are con- stantly changing, thereby creating additional variability in the network connectivity. Power and energy constraints, in- terference, and the shared nature of the wireless medium re- quire adaptive relaying mechanisms and channel access. In such a harsh environment, robustness and quality of service (QoS) are essential. MANETs usually consist of a heteroge- neous mixture of nodes with a variety of traffictypesand different QoS requirements. Scaling laws for these networks are not fully understood. Diverse tr adeoff studies related to capacity, delay, bandwidth, and energy consumption are cur- rently under intense investigation. This special issue, which adds one more collection of contributions to the vibrant field of ad hoc networking, includes 6 papers that address some of these issues. The first paper by S. Xu et al. investigates the reliability of communications paths in mobile ad hoc networks. They demonstrate an analysis framework for some mobility met- rics such as link persistence, link duration, link availability, link residual time, and so forth. The second paper by D. Noh and H. Shin introduces an efficient way to handle service advertisement and discovery in MANETs so as to avoid re- dundant flooding and to lower overhead. The third paper by M. D. Colagrosso investigates the use of machine learn- ing to facilitate adaptive intelligent broadcasting protocols in MANETs. The forth paper by C. Comaniciu and H. V. Poor introduces a cross-layer design that increases energy ef- ficiency in MANETs through joint optimization of transmit power and routing selection. The fifth paper by L. Qian et al. develops a joint power control and routing algorithm for CDMA in wireless ad hoc networks. The sixth and last pa- per by E. Perevelov et al. studies scaling laws for ad hoc net- works taking into account the overhead in route discovery algorithm. ACKNOWLEDGEMENTS We would like to thank the authors for their contributions and the reviewers for their thorough reviews. Hamid R. Sadjadpour Robert Ulman Ananthram Swami Anthony Ephremides . Corporation EURASIP Journal on Wireless Communications and Networking Volume 2007, Article ID 63708, 1 page doi:10.1155/2007/63708 Editorial Wireless Mobile Ad Hoc Networks Hamid R. Sadjadpour, 1 Robert Ulman, 2 Ananthram. vibrant field of ad hoc networking, includes 6 papers that address some of these issues. The first paper by S. Xu et al. investigates the reliability of communications paths in mobile ad hoc networks algorithm for CDMA in wireless ad hoc networks. The sixth and last pa- per by E. Perevelov et al. studies scaling laws for ad hoc net- works taking into account the overhead in route discovery algorithm. ACKNOWLEDGEMENTS We