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The National Broadband Network (NBN), announced by then Labour Prime Minister,--Kevin Rudd, in April 2009, promised a new national fibre-to-the-premises network, designed within eight years to connect 90% of Australian [...]

Information about the solution developed by the End-to-End Efficiency research project is provided. The focus is on automated network self-management, which is based on cognition, self-organization, and self-reconfiguration. The two main challenges for mobile communication systems are also discussed.

A study was conducted to propose a Celnet Xplorer-based self-optimizing network (SON) architecture that enables detailed analysis of network performance. The use of highly efficient, autonomic self-optimization and configuration processes is needed in order to meet performance objectives in Long Term Evolution (LTE) networks.

We present a robust approach to multiple-vehicle tracking, which combines deterministic and probabilistic methods. The observation model is built with an improved color correlogram, which is a feature vector with a compact correlogram using overlapping fragmentation to make the ideal form to measure similarity with a Bhattacharyya coefficient. The observation and state model of multiple vehicles is given under a CamShiff framework. To overcome the disadvantage of particle impoverishment, a layered particle filter architecture embedding Camshift is proposed, which considers both the concentration and the diversity of the particles, and the particle set can better represent the posterior probability density. We also present experiments using a real video sequence to verify the proposed method. OCIS codes: 100.4993, 100.4999, 100.5010.

The P300 component of Event Related Brain Potentials (ERP) is commonly used in Brain Computer Interfaces (BCI) to translate the intentions of an individual into commands for external devices. The P300 response, however, resides in a signal environment of high background noise. Consequently, the main problem in developing a P300-based BCI lies in identifying the P300 response in the presence of this noise. Traditionally, attenuating the background activity of P300 data is done by averaging multiple trials of recorded signals. This method, though effective, suffers two drawbacks. First, collecting multiple trials of data is time consuming and delays the BCI response. Second, latency distortions may appear in the averaged result due to variable time-locking of the P300 in the individual trials. Problem statement: The use of single-trial P300 data overcomes both these shortcomings. However, single-trial data must be properly denoised to allow for reliable BCI operation. Single-trial P300-based BCIs have been implemented using a variety of signal processing techniques and classification methodologies. However, comparing the accuracies of these systems to other multi-trial systems is likely to include the comparison of more than just the trial format (single-trial/multi-trial) as the data quality and recording circumstances are likely to be dissimilar. Approach: This issue was directly addressed by comparing the performance comparison of three different preprocessing agents and three classification methodologies on the same data set over both the single-trial and multi-trial settings. The P300 data set of BCI Competition II was used to facilitate this comparison. Results: The LDA classifier exhibited the best performance in classifying unseen P300 spatiotemporal features in both the single-trial (74.19%) and multi-trial format (100%). It is also very efficient in terms of computational and memory requirements. Conclusion: This study can serve as a general guide for practitioners developing single-trial and multi-trial P300-based BCI systems, particularly for selecting appropriate pre-processing agents and classification methodologies for inclusion. The possibilities for future study include the investigation of double-trial and triple-trial P300 system based on the LDA classifier. The time savings of such approaches will still be significant. It is very likely that such systems would benefit from accuracies higher than the one obtained in this study for single-trial LDA (74.19%). Key words: Electroencephalography, P300, principal component analysis, genetic algorithm, linear discriminant analysis, INTRODUCTION A Brain Computer Interface (BCI) is a system that permits users to control external devices using only their inherent brain activity. Device control is achieved by performing a cognitive [...]

Wireless mesh networks extend the connectivity range of mobile devices by using multiple access points, some of them connected to the Internet, to create a mesh topology and forward packets over multiple wireless hops. However, the quality of service provided by the mesh is impaired by the delays and disconnections caused by handoffs, as clients move within the area covered by multiple access points. We present the architecture and protocols of SMesh, the first transparent wireless mesh system that offers seamless, fast handoff, supporting real-time applications such as interactive VoIP. The handoff and routing logic is done solely by the access points, and therefore connectivity is attainable by any 802.11 device. In SMesh, the entire mesh network is seen by the mobile clients as a single, omnipresent access point, giving the mobile clients the illusion that they are stationary. We use multicast for access points coordination and, during handoff transitions, we use more than one access point to handle the moving client. SMesh provides a hybrid routing protocol that optimizes routes over wireless and wired links in a multihomed environment. Experimental results on a fully deployed mesh network demonstrate the effectiveness of the SMesh architecture and its intra-domain and inter-domain handoff protocols. Categories and Subject Descriptors: C.2.1 [Computer-Communication Networks]: Network Architecture and Design--Wireless communication General Terms: Design, Experimentation Additional Key Words and Phrases: Wireless mesh networks, fast handoff, intra-domain, interdomain, micromobility ACM Reference Format: Amir, Y., Danilov, C., Musaloiu-Elefteri, R., and Rivera, N. 2010. The SMesh wireless mesh network. ACM Trans. Comput. Syst. 28, 3, Article 6 (September 2010), 49 pages. DOI = 10.1145/1841313.1841314 http://doi.acm.org/10.1145/1841313.1841314

Mobile wireless networks, such as mobile ad hoc networks (MANETs), are vulnerable to passive attacks that threaten the privacy of communications. Moreover, threats can now be launched from mobile platforms and with new techniques for eavesdropping, locating, and fingerprinting wireless transmissions. Recently, many wireless anonymous schemes have been studied, and mobility often plays an important role with regard to the effectiveness of wireless anonymity. In this paper, we focus on the impact of node motion behaviors. We first illustrate the emerging anonymity threat of venue privacy attacks (VPAs) to trace mobile wireless nodes. We then propose 'motion-MIX' as the countermeasure to defend against the threat. Motion-MIX calls for protection at all the layers of the protocol stack. We further use a new asymptotic security model to verify motion-MIX's effectiveness against VPAs. In a scalable ad hoc network, we prove that the probability of security breach is negligible with respect to the number of network nodes. Index Terms--Anonymity, mobile ad hoc network (MANET), mobile tracing, motion MIX.

Energy minimization is an important design goal in wireless video transmission. We examine how the RF energy and the analog circuit energy, which account for a large part of the energy consumption for wireless video transmission, can be controlled with physical-layer parameters (e.g., modulation level, bit rate, bit error rate, and multiple access interference) and link-layer specifications (e.g., the buffer status, idle time, and active time). Building on these insights, we develop three energy-efficient video transmission schemes for the single-user system, i.e., frame-by-frame transmission, group of pictures (GOP)-by-GOP transmission, and client-buffer-related energy-efficient video transmission (CBEVT). Our simulations indicate that energy savings of up to 85% is achievable in the radio frequency (RF) front end using the CBEVT algorithm. We also present an energy-efficient optimal smoothing algorithm for reducing the RF front-end energy consumption and the peak data rate. For CDMA-based multiuser systems, we propose an RF front-end energy model that assumes perfect power control. We find the signal-to-interference-noise ratio (SINR) for the entire system that minimizes the total energy consumption. We propose the multiuser-based energy-efficient video transmission (MBEVT) algorithm, which can achieve energy savings of up to 38% for a six-user CDMA system with an independent 16-MB buffer for every uplink. Index Terms--Energy efficiency, radio frequency (RF) front end, wireless video.

This tutorial presents enhancements to an open-source wireless network discussed in the June 2007 issue of ITAL that should reduce its administrative burden. In addition, it will demonstrate an open-source […]

The application of the Lagrange relaxation theory to perform integer programming, during the design of wireless telecommunications networks for capacity expansion of broadband wireless access, is described.

A method for deciding when to invest in wireless networks capacity management, using real options, is presented.

Abstract: In order to disperse the load on a Web server, generally the server cluster is configured to distribute access requests, or mirror servers are distributed geographically on different networks. [...]

Abstract: The recent advances in wireless communication technology and the unprecedented growth of the Internet have paved the way for wireless networking and IP mobility. Mobile Internet protocol has been [...]

This letter proposes a very low-complexity maximum-likelihood (ML) detection algorithm based on QR decomposition for the quasi-orthogonal space-time block code (QSTBC) with four transmit antennas, called the LC-ML decoder. The proposed algorithm enables the QSTBC to achieve ML performance with significant reduction in computational load for any high-level modulation scheme. Index Terms--Diversity, maximum-likelihood (ML) detection, multiple-input multiple-output (MIMO), space-time coding, wireless communication.

In the present paper, a call admission control scheme that can learn from the network environment and user behavior is developed for code division multiple access (CDMA) cellular networks that handle both voice and data services. The idea is built upon a novel learning control architecture with only a single module instead of two or three modules in adaptive critic designs (ACDs). The use of adaptive critic approach for call admission control in wireless cellular networks is new. The call admission controller can perform learning in real-time as well as in offline environments and the controller improves its performance as it gains more experience. Another important contribution in the present work is the choice of utility function for the present self-learning control approach which makes the present learning process much more efficient than existing learning control methods. The performance of our algorithm will be shown through computer simulation and compared with existing algorithms. Index Terms--Adaptive critic designs (ACDs), approximate dynamic programming, call admission control, code division multiple access (CDMA), cellular networks, neural dynamic programming, wireless networks.

Controlling transmitted power in a wireless network is critical for maintaining quality of service, maximizing channel utilization and minimizing near-far effect for suboptimal receivers. In this paper, a general proportional-integral-derivative (PID) type algorithm for controlling transmitted powers in wireless networks is studied and a systematic way to adapt or tune the parameters of the controller in a distributed fashion is suggested. The proposed algorithm utilizes multiple candidate PID gains. Depending on the prevailing channel conditions, it selects an optimal PID gain from the candidate gain set at each instant and places it in the feedback loop. The algorithm is data driven and can distinguish between stabilizing and destabilizing controller gains as well as rank the stabilizing controllers based on their performance. Simulation results indicate that the proposed scheme performs better than several candidate controllers, including a well known distributed power control (DPC) algorithm. Index Terms--multiple controller adaptive control (MCAC), proportional-integral-derivative (PID) tuning and adaptation, power control, switched system, unfalsified control, wireless cellular system.

Designers face many system optimization problems when building distributed systems. Traditionally, designers have relied on optimization techniques that require either prior knowledge or centrally managed runtime knowledge of the system's environment, but such techniques are not viable in dynamic networks where topology, resource, and node availability are subject to frequent and unpredictable change. To address this problem, we propose collaborative reinforcement learning (CRL) as a technique that enables groups of reinforcement learning agents to solve system optimization problems online in dynamic, decentralized networks. We evaluate an implementation of CRL in a routing protocol for mobile ad hoc networks, called SAMPLE. Simulation results show how feedback in the selection of links by routing agents enables SAMPLE to adapt and optimize its routing behavior to varying network conditions and properties, resulting in optimization of network throughput. In the experiments, SAMPLE displays emergent properties such as traffic flows that exploit stable routes and reroute around areas of wireless interference or congestion. SAMPLE is an example of a complex adaptive distributed system. Index Terms--Feedback, learning systems, mobile ad hoc network routing.

The cumulative distribution function (Cdf) of the failure recovery time for client-server applications in mobile wireless environments characterized by logging and mobility handoff strategies is analyzed. The largest cost investment returns in terms of improved failure recoverability are obtained with the application of eager mobility handoff strategy instead of the lazy mobility handoff strategy.

A technique employing the use of parallel feeds is applied to the recently proposed L-probe coupled patch antenna design. By employing only two L-probes, with proper separation, for feeding one single patch, a twin-L-probe coupled patch antenna is designed with both high-gain (10 dBi) and wide-band [25%, standing wave radio (SWR) [less than or equal to] 1.5] characteristics. In addition, the 1-dB-gain bandwidth is around 26%, which covers the impedance bandwidth. Furthermore, a noticeable suppression of cross-polarization radiation is observed. Simulation results are in good agreement with those noteworthy characteristics obtained from experiments. The proposed antenna is suitable for modern mobile communication applications. Index Terms--High-gain antenna, L-probe, low cross-polarization, wide-band antenna.