This paper analyzes the average bit error rate performance of reception diversity in fading channels. The analysis provides the upper bounds on the bit error rate probability for differentially coherent detection in correlated Nakagami-Rice fading channels and coherent detection with channel phase information in uncorrelated Nakagami-Rice fading channels. Both bounds are derived by developing the Chernoff bound for the pairwise error probabilities. Numerical examples compare the analysis bounds with the simulation results.

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This letter proposes an interference cancellation method for Multiple Input Multiple Output - Orthogonal Frequency Division Multiplexing (MIMO-OFDM) adaptive array, which utilizes periodical preamble signals. A short preamble signal of IEEE802.11 based OFDM signal are mapped in only twelve subcarriers in a frequency domain and the signal in a time domain is transformed by Inverse Fast Fourier Transform (IFFT) at the transmitter. At the receiver site, the subcarriers at which only interference arrive can be found by employing Fast Fourier Transform (FFT). The propose method utilize this feature and efficiently reduce the interference by utilizing the null subcarriers which is not mapped in the short preamble signal. By a computer simulation, it is shown that the proposed method with the smaller number of training signals can obtain same Bit Error Rate (BER) performance compared to the conventional Minimum Mean Square Error (MMSE) adaptive array.

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Radio frequency identification (RFID) system is developing quickly in recent years, and its industry including logistics management, automatic object identification, etc. Moreover, it is suggested to combine with in-body wireless communication to reduce medical error and receive the patients’ information without connecting cable lines in hospitals. In this paper, we proposed an implantable RFID antenna which is designed to operate at 2.4GHz (2.4-2.485GHz) and matched a IC chip with conjugate impedance of 9.3-j55.2Ω. The good impedance matching can be obtained by adding loop structure, and moreover, miniaturization of antenna is achieved by folded structure. Therefore, the whole size of proposed antenna with glass coating is only 9.3mm × 1.0mm × 1.0mm. The impedance characteristic of implantable RFID antenna is simulated by use of finite element method (FEM) and the experiment is implemented with three-layered phantom which represents human upper arm.

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This letter proposes two biological activity detection methods using MIMO system and compares them. These methods detect the biological activity of human by using the time-variant MIMO channel and improve the detection sensitivity by using the multi-antennas. Experiment and simulation results demonstrate the proposed method can improve the detection sensitivity than the detection method using SISO system.

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Lattice-reduction is an effective technique to improve the performance of MIMO data detection. This paper presents a quantization error reduction scheme for MIMO detection based on orthogonal lattices. The motivation of the proposed detection is to solve the problem of degrading the performance due to the rounding quantization error in the signal estimate stage. The simulation results exhibit that the proposed detection can achieve the near-ML performance with a little additional complexity in the high E_b/N₀ region. In addition, this quantization error reduction scheme is efficient even for the high modulation order.

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This paper describes a novel time synchronization algorithm for the WSN of bridge health diagnosis system. In previous work, we develop a time synchronization algorithm, named DMLTS [1], for this WSN. To reduce energy consumption, this time synchronization improves the time-synch phase of DMLTS and utilizes an improved energy feedback scheme to lengthen the lifetime of WSN and reduce synchronization error. Performance analyses, simulations and realization in node hardware of WSN are also presented. They proved that: this algorithm has a better synchronization error performance, can decrease overhead, consume less energy, and lengthen the lifetime of WSN.

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Currently, problem of battery life is restricting the development of almost all of the wireless sensor networks, especially in structural health monitoring. This paper proposes and proves the possibility of a continuous battery life solution for wireless sensor networks using wireless power transfer. Different from current mainstream methods using resonance coils, this research is using 950MHz electric waves for power transfer. Experiment results shows that this power transfer system is able to support sensor modules operation at 10m distance under current structure monitoring plan. Also, this system is able to recharge batteries at 16m distance maximum.

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This paper presents a directional base station antenna for a distributed transmitting antenna arrangement to enhance the channel capacity of multiple-input multiple-output (MIMO) communication system in the line-of-sight (LOS) environment. We verify our simulation results of a ray-tracing technique under indoor environment.

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This paper discusses optical diversity transmission through multi-core fiber and the use of maximum-ratio combined reception to mitigate fiber non-linear distortion. The maximum-ratio combining theory for microwave communication systems is extended to optical transmission. This scheme allows increases in the optical fiber launched power and thus enhances Q-factor by 2 and 4dB for two and four core diversity transmission, respectively.

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The Adaptive Modulation (AM) for Space-Time Block Code OFDM (STBC-OFDM) is addressed in this article as application for wireless systems. A new method was proposed, which is used the dispersion of Error Vector Magnitude (EVM) to represent the current channel condition in the following frames and to select the appropriate Modulation Scheme (MS) for the subsequent frame. In this method, the AM is not only compensated the channel variation, but also guaranteed the required Bit Error Rate (BER) performance and maximized the Spectral Efficiency (SE). The simulation shows that the proposed scheme outperforms in gaining performance the conventional scheme for all MS over a fading channel.

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A novel packet filter reconfiguration method was proposed by Hamed et al. We found that this method has the potential to cause a policy violation. We improve Hamed’s method without increasing the time complexity so as to maintain rule dependencies.

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