Dielectric-loaded waveguides and resonators operating in microwave frequency bands have been successfully used for measuring displacement in structures, detecting gaps between concrete and metal surfaces, and monitoring cracks. This paper presents a novel dielectric resonator antenna (DRA) that operates in the X-band (8.2 – 12.4 GHz) that can be used for structural health monitoring applications. The proposed DRA is initially designed and optimized to operate in free space, and then embedded in a concrete block and its performance is analyzed. The simulated and measured magnitude of reflection coefficient, $S_{11}$, are in good agreement. The modeled DRA has the potential to be used for structural health monitoring applications.

In this paper, we study the compatibility of operating multiple Long Term Evolution (LTE) mobile handheld devices in the digital dividend spectrum identified in Australia. European studies provide some valuable insights on the operation of mobile services in the digital dividend, the results however do not provide a direct comparison due to difference in the DVB-T transmission band plan, the DVB-T channel bandwidth and the preferred duplexing arrangement. The European studies also only take into consideration compatibility of operating single LTE handheld devices in adjacent bands. Thus our study is into the impact of multiple LTE transmission on the DVB-T reception in the boundary of the Australian digital dividend using Monte Carlo simulations.

This paper presents an improved wireless MAC protocol that enables IEEE 802.15.4 based WSNs to provide an energy-efficient, reliable, and delay-limited data transmission for hybrid monitoring applications. The proposed protocol is implemented in ns-2, and its performance is evaluated in terms of energy consumption, delay, and reliability in data transmission. Extensive simulations verify the improved performance of the proposed protocol in hybrid monitoring applications.

The power allocation problem in a two-hop OFDM amplify-and-forward (AF) relay link is studied when the available channel state information (CSI) is an outdated, but correlated version of the actual instantaneous CSI. We propose a power loading scheme to maximize the outage rate. The outage rate achieved by the proposed approach is compared with uniform power allocation and instantaneous rate maximization to study the effectiveness of adaptive power loading when the available CSI is outdated. Results confirm that the proposed method achieves higher outage rate than the other two methods.

A fast simulation method is proposed for accurate performance evaluation of error control coded systems. The proposed method, iterative flat histogram two-phase algorithm (IFH-TPA), addresses the issue of long simulation times required by Monte Carlo (MC) simulations to estimate very low error probabilities. IFH-TPA employs Wang-Landau (WL) flat histogram Monte Carlo method for efficient sampling of rare events that lead to bit errors in decoded sequences. A Viterbi decoder simulation scenario validates that IFH-TPA can provide sample size reductions in the order of 1000 in estimating error rates as low as 10-9for a rate 1/2 convolutional code of constraint length 7 in AWGN channels. Further, IFH-TPA estimations agree well with MC estimations and the union bound of the code.

This study presents the importance sampling (IS) analysis for the efficient simulation of orthogonal frequency division multiplexing (OFDM) systems. Importance sampling is an efficient rare-event simulation technique that aims at reducing the simulation runtime by reducing the variance of the estimator. The efficiency of IS highly relies on the proper selection of the biased simulation density function. This paper considers the problem of biasing the simulation density function of OFDM systems for achieving higher variance reduction gains and computational efficiencies. In particular, the authors show how to bias the time domain noise density function and how to correct the biased error count at the receiver in the frequency domain of an OFDM system operating over multipath fading channels with minimum mean square error equalisation. Further, the authors obtain the optimum biasing parameters for variance scaling method and mean translation method applied to bias the noise density function. The presented results can easily be generalised to OFDM systems operating over additive white Gaussian noise (AWGN) channels. The simulation results demonstrate that extensive gains in estimator variance reduction can be achieved through the proposed analysis rather than by using conventional Monte-Carlo simulations.

Communication over Multiple-Input Multiple-Output (MIMO) fading channels is of much interest in the current telecommunication context. Estimation of very small outage probabilities in such channels is an important, yet time consuming task, owing to the lengthy run-time requirements of traditional Monte Carlo (MC) simulations. Hence, fast and accurate methods for estimating outage capacities are of necessity. Importance sampling (IS) has been the most widely used efficient simulation tool for telecommunication networks in the past. However, IS requires an in-depth knowledge of the system to explore the optimal biasing distribution. The method described in this paper uses the concept of Multicanonical Monte Carlo (MMC) for the quick simulation of outage probabilities in MIMO channels. MMC can be considered an adaptive IS technique which employs a blind adaptation algorithm to converge to the optimal biasing distribution. Here, we elaborate the use of MMC and present an algorithm for efficient simulation of outage probabilities of Rayleigh fading MIMO channels. This method can easily be extended to other fading models of interest. Numerical results, which extend the known results in literature, of the MMC simulations in comparison with that of the MC simulations are presented.

In a paper by Rimoldi (see ibid., vol.39, no.9, p.1280, 1991) the closed-form expression for the minimum squared Euclidean distance of continuous-phase frequency-shift-keyed (CPFSK) signals with modulation index h/spl les/1/2 was derived. The authors extend the result derived by Rimoldi to include any rational modulation index.>