Issue 1 • Date First Quarter 2011
Editorial for First Quarter 2011 IEEE Communications Surveys & TutorialsPage(s): 1 - 2| | PDF (82 KB)
This survey guides the reader through the extensive open literature that is covering the family of low-density parity-check LDPC codes and their rateless relatives. In doing so, we will identify the most important milestones that have occurred since their conception until the current era and elucidate the related design problems and their respective solutions. View full abstract»
The present article carries out a review of MIMO-based techniques that have been recently proposed for satellite communications. Due to the plethora of MIMO interpretations in terrestrial systems and the particularities of satellite communications, this review is built on two pillars, namely fixed satellite and mobile satellite. Special attention is given to the characteristics of the satellite channel, which will ultimately determine the viability of MIMO over satellite. Finally, some future research directions are identified. View full abstract»
Recently, IEEE started a task group to investigate adding wireless mesh capabilities to its ubiquitous IEEE 802.11 wireless local area networks standard. The proposal is specified as the IEEE 802.11s amendment. Although the IEEE802.11s amendment is still a draft, some implementations based on it may already be found. The first and most widespread of these implementations is the one developed by One Laptop per Child (OLPC) for its educational laptop - the XO. One notable feature of IEEE 802.11s is the fact that the mesh network is implemented at the link layer, relying on MAC addresses rather than IP addresses for its mechanisms. This feature enables the design and development of new CPU-free network devices that provide layer-2 multihop communication. This tutorial describes the main characteristics of the IEEE 802.11s proposal illustrating the advantages and disadvantages of the MAC layer approach in comparison to the traditional layer three paradigm to multihop wireless networks. To achieve this, this work provides a detailed analysis of 802.11s traffic captured in a real testbed, with special attention to the path discovery mechanism. The step by step explanation of the mesh mechanisms highlights how some of the design choices may impact on the scalability and reliability of such networks. View full abstract»
Wireless sensor networks (WSNs) are networks of distributed autonomous devices that can sense or monitor physical or environmental conditions cooperatively. WSNs face many challenges, mainly caused by communication failures, storage and computational constraints and limited power supply. Paradigms of computational intelligence (CI) have been successfully used in recent years to address various challenges such as data aggregation and fusion, energy aware routing, task scheduling, security, optimal deployment and localization. CI provides adaptive mechanisms that exhibit intelligent behavior in complex and dynamic environments like WSNs. CI brings about flexibility, autonomous behavior, and robustness against topology changes, communication failures and scenario changes. However, WSN developers are usually not or not completely aware of the potential CI algorithms offer. On the other side, CI researchers are not familiar with all real problems and subtle requirements of WSNs. This mismatch makes collaboration and development difficult. This paper intends to close this gap and foster collaboration by offering a detailed introduction to WSNs and their properties. An extensive survey of CI applications to various problems in WSNs from various research areas and publication venues is presented in the paper. Besides, a discussion on advantages and disadvantages of CI algorithms over traditional WSN solutions is offered. In addition, a general evaluation of CI algorithms is presented, which will serve as a guide for using CI algorithms for WSNs. View full abstract»
The rapid increase of the number of mobile subscribers as well as the deployment of 3G technologies are putting strain on mobile backhaul operational expenditures (OPEX) which amount to 20-40% of total mobile operator's OPEX due to their reliance on T1/E1 copper lines. For these reasons, the current backhaul systems, a term commonly used to describe connectivity between base stations and radio controllers, are increasingly integrating more cost-effective, packet switched technologies, especially Ethernet/Internet technologies. In addition, Wi-Fi and WiMAX are emerging as promising backhaul solutions and initial findings have demonstrated their feasibility. However, the notion of network migration unavoidably raises new technical challenges relevant to aspects of TDM and packet network timing synchronization, QoS, and packet efficiency. This survey aims to provide a comprehensive study of state-of-the-art circuit switched and emerging packet switched backhaul technologies based on research articles and standard documents. For packet switched backhaul, we focus on the practically important Pseudowire approaches which are used to transport TDM services over packet switched networks. We also discuss the features and research findings on the use of Wi-Fi and WiMAX technologies which illustrate their potential for rapid and cost-efficient backhaul deployment. Finally, we highlight some open issues relevant to timing synchronization in wireless mesh backhaul and femtocells deployments, which offer a rich ground for further research. View full abstract»
Optical layer monitoring and fault localization serves as a critical functional module in the control and management of optical networks. An efficient monitoring scheme aims at minimizing not only the hardware cost required for 100% link failure localization, but also the number of redundant alarms and monitors such that the network fault management can be simplified as well. In recent years, several optical layer monitoring schemes were reported for fast and efficient link failure localization, including simple, non-simple monitoring cycle (m-cycle) and monitoring trail (m-trail). Optimal ILP (Integer Linear Program) models and heuristics were also proposed with smart design philosophy on flexibly trading off different objectives. This article summarizes those innovative ideas and methodologies with in-depth analysis on their pros and cons. We also provide insights on future research topics in this area, as well as possible ways for extending the new failure localization approaches to other network applications. View full abstract»
The expansion of new technologies is expected to offer economic growth in the wired and wireless technological networking environment, while at the same time, it will offer a wide variety of services and give the possibility for utilizing technologies for the benefit of many subscribers. The Pricing Schemes are designed to offer profitable business to the Wireless Service Providers (WSPs), as well as, to create favorable services for the mobile subscribers and eventually to get charged according to their services usage. In this paper, the Pricing Schemes are classified, based on their ability to adapt to the needs of the WSPs and their subscribers during the entire service period, into Static-based Pricing and Dynamic-based Pricing Schemes. The Pricing Schemes are also analyzed in detail and are further classified according to the factors involved in the price calculation of a service, i.e. the Service Level Agreement (SLA), the subscription type, the negotiation capabilities between WSPs and their subscribers, the network capacity, the available bandwidth and frequency spectrum, the network hops, and the Base Stations (BSs). The affected elements by the pricing network are also discussed, together with the performance evaluation of the presented pricing schemes. View full abstract»
2010 IEEE Communications Surveys and Tutorials ReviewersPage(s): 146 - 147| | PDF (47 KB)
Aims & Scope
IEEE Communications Surveys & Tutorials is an online journal published by the IEEE Communications Society for tutorials and surveys covering all aspects of the communications field. Telecommunications technology is progressing at a rapid pace, and the IEEE Communications Society is committed to providing researchers and other professionals the information and tools to stay abreast.
Meet Our Editors
Ekram Hossain, Ph.D., P.Eng.
University of Manitoba