This paper presents the performance of outer-loop control for selecting the best modulation and coding scheme (MCS) based on mutual information (MI) for orthogonal frequency division multiplexing (OFDM) multiple-input multiple-output (MIMO) spatial division multiplexing (SDM). We propose an outer-loop control scheme that updates the measured MI per information bit value for selecting the best MCS from a mapping table that associates the block error rate (BLER) and MI per bit instead of directly updating the MCS selection threshold so that the required BLER is satisfied. The proposed outer-loop control is applicable to continuous data transmission including intermittent transmission with a short blank period. Moreover, we compare the measured BLER and throughput performance for two types of outer-loop control methods: instantaneous block error detection and moving-average BLER detection. In the paper, we use maximum likelihood detection (MLD) for MIMO SDM. Computer simulation results optimize the step size for the respective outer-loop control schemes for selecting the best MCS that achieves the higher throughput and the target BLER simultaneously. Computer simulation results also show that by using the most appropriate step size, the outer-loop control method based on the instantaneous block error detection of each physical resource block is more appropriate than that based on the moving-average BLER detection from the viewpoints of achieving the target BLER more accurately and higher throughput.

Considering worse-case channel uncertainties, we investigate the robust energy efficient (EE) beamforming design problem in a K-user multiple-input-single-output (MISO) interference channel. Our objective is to maximize the worse-case sum EE under individual transmit power constraints. In general, this fractional programming problem is NP-hard for the optimal solution. To obtain an insight into the problem, we first transform the original problem into its lower bound problem with max-min and fractional form by exploiting the relationship between the user rate and the minimum mean square error (MMSE) and using the min-max inequality. To make it tractable, we transform the problem of fractional form into a subtractive form by using the Dinkelbach transformation, and then propose an iterative algorithm using Lagrangian duality, which leads to the locally optimal solution. Simulation results demonstrate that our proposed robust EE beamforming scheme outperforms the conventional algorithm.

Open-loop (OL) transmit diversity is more subject to the influence of channel estimation error than closed-loop (CL) transmit diversity, although it has the merit of providing better performance in fast Doppler frequency environments because it doesn't require a feedback signal. This paper proposes an OL transmit diversity scheme combined with intra-subframe frequency hopping (FH) and iterative decision-feedback channel estimation (DFCE) in a shared channel for discrete Fourier transform (DFT)-precoded orthogonal frequency division multiple access (OFDMA). We apply intra-subframe FH to OL transmit diversity to mitigate the reduction in the diversity gain under high fading correlation conditions among antennas and iterative DFCE to improve the channel estimation accuracy. Computer simulation results show that the required average received signal-to-noise power ratio at the average block error rate (BLER) of 10-2 of the space-time block code (STBC) with intra-subframe FH is reduced to within approximately 0.8dB compared to codebook-based CL transmit diversity when using iterative DFCE at the maximum Doppler frequency of fD =5.55Hz. Moreover, it is shown that STBC with intra-subframe FH and iterative DFCE achieves much better BLER performance compared to CL transmit diversity when fD is higher than approximately 30Hz since the tracking ability of the latter degrades due to the fast fading variation in its feedback loop.

Object extraction and tracking in a video image is basic technology for many applications, such as video surveillance and robot vision. Many moving object extraction and tracking methods have been proposed. However, they fail when the scenes include illumination change or light reflection. For tracking the moving object robustly, we should consider not only the RGB values of input images but also the shape information of the objects. If the objects' shapes do not change suddenly, matching positions on the cost matrix of exclusive block matching are located nearly on a line. We propose a method for obtaining the correspondence of feature points by imposing a matching position constraint induced by the shape constancy. We demonstrate experimentally that the proposed method achieves robust tracking in various environments.

In this paper, we present a new electro-optic (EO) probing system based on heterodyne detection. The use of a recirculating frequency shifter allows to expand the bandwidth of the system far beyond what is attainable with a conventional heterodyne EO set-up. The performance for the frequencies up to 50GHz is analysed to forecast the viability of the system up to the THz range.

Time redundancy is sometimes an only option for enhancing circuit reliability when the circuit area is severely restricted. In this paper, a time-redundant error-correction scheme, which is particularly suitable for coarse-grained reconfigurable arrays (CGRAs), is proposed. It judges the correctness of the executions by comparing the results of two identical runs. Once a mismatch is found, the second run is terminated immediately to start the third run, under the assumption that the errors tend to persist in many applications, for selecting the correct result in the three runs. The circuit area and reliability of the proposed method is compared with a straightforward implementation of time-redundancy and a selective triple modular redundancy (TMR). A case study on a CGRA revealed that the area of the proposed method is 1% larger than that of the implementation for the selective TMR. The study also shows the proposed scheme is up to 2.6x more reliable than the full-TMR when the persistent error is predominant.

The authors have been researching on reducing the power consumption of microprocessors, and developed a low-power processor called “Geyser” by applying power gating (PG) function to the individual functional units of the processor. PG function on Geyser reduces the power consumption of functional units by shutting off the power voltage of idle units. However, the energy overhead of switching the supply voltage for units on and off causes power increases. The amount of the energy overhead varies with the behavior of each functional unit which is influenced by running application, and also with the core temperature. It is therefore necessary to switch the PG function itself on or off according to the state of the processor at runtime to reduce power consumption more effectively. In this paper, the authors propose a PG control method to take the power overhead into account by the operating system (OS). In the proposed method, for achieving much power reduction, the OS calculates the power consumption of each functional unit periodically and inhibits the PG function of the unit whose energy overhead is judged too high. The method was implemented in the Linux process scheduler and evaluated. The results show that the average power consumption of the functional units is reduced by up to 17.2%.

In this paper the amplitude probability distribution (APD) measurement method is applied to evaluate noise coupling to an antenna on an evaluation board that uses mixed RF and digital signals of an IC. We analytically investigate noise coupling path to the antenna where the correlation coefficient matches the APD curve of the evaluation board. Moreover, in order to verify the analysis results, the noise coupling path in the board is evaluated by measurements involving In-phase/Quadrature (I/Q) signals as well as electromagnetic simulations. As a result, we demonstrate that APD method is effective in evaluating a degree of noise coupling from an IC to multiple antennas on the board, and confirm that the intensity of noise coupling to each antenna is affected greatly by the board layout patterns.

In wireless sensor networks, or WSNs, a malicious node is able to cover itself by switching between good and bad behaviors. Even when running under a reputation mechanism, such a node can still behave maliciously now and then so long as its reputation is within the acceptable level. To address this inconsistent behavior issue, a combined approach of statistic reputation and time series is proposed in this study, in which the negative binomial reputation is applied to rate the nodes' reputation and concept of time series is borrowed to analyze the reputation results. Simulations show that the proposed method can effectively counter inconsistent behavior nodes and thus improves the overall system performance.

A digital spatial modulation method has been demonstrated for a wireless power transmission system at 5.8 GHz. Interference of electromagnetic waves, which are radiated from the dual scatterers, successfully realizes the spatial modulation. The spatial modulation is performed with a digital modulation manner by controlling capacitances embedded in one of the dual scatterers so that the interference of the scattered waves is appropriately changed. Switch MMICs based on p-HEMT technology was newly developed for the spatial modulation. Measured insertion losses of the switch MMIC are 1.0 dB and 14 dB for on and off states at 5.8 GHz, respectively. The isolation is more than 20 dB. With the switch MMIC, digital spatial modulation characteristics were experimentally demonstrated at 5.8 GHz. One-bit amplitude shift keying (ASK) for 1 MHz signal was realized at 5.8 GHz, and two levels were clearly discriminated. The modulation factor is 36%. In addition, 2-bit ASK signal was detected at 7.1 GHz.

A miniaturized patch hybrid coupler with arbitrary power ratio and impedance transformation is proposed and designed by loading a pair of asymmetric cross slots on a squared patch resonator. To obtain the arbitrary power ratio and impedance transformation, the rectangular size of stepped slot ends should be well designed to be asymmetry and thus to obtain the different inductive loadings along two current paths. Theoretically, the equivalent transmission line model is first developed to understand the physical relationship between the patch and traditional branch-line hybrids. The matching/isolation and power ratio conditions are then derived at center frequency. By following a detailed design guideline, a prototype of the hybrid with 1:2 power ratio and 1:1.3 impedance transformation is designed and fabricated at 4.2 GHz. The measured results show a good agreement with simulated results, where the measured -10 dB impedance bandwidth achieves 18% and the bandwidth of 90°±6° phase difference is about 35% in a frequency range from 3.5 GHz to 5 GHz.

A power allocation to active and reactive power in stochastic resonance is discussed for energy harvesting from noise. It is confirmed that active power can be increased at stochastic resonance, in the same way of the relationship between energy and phase at an appropriate setting in resonance.

In this paper, for an odd prime p and i=0,1, we investigate the cross-correlation between two decimated sequences, s(2t+i) and s(dt), where s(t) is a p-ary m-sequence of period pn-1. Here we consider two cases of ${d}$, ${d=rac{(p^m +1)^2}{2} }$ with ${n=2m}$, ${p^m equiv 1 pmod{4}}$ and ${d=rac{(p^m +1)^2}{p^e + 1}}$ with n=2m and odd m/e. The value distribution of the cross-correlation function for each case is completely determined. Also, by using these decimated sequences, two new p-ary sequence families of period ${rac{p^n -1}{2}}$ with good correlation property are constructed.

We introduce a coding theoretic criterion for Yamamoto's strong security of the ramp secret sharing scheme. After that, by using it, we show the strong security of the strongly multiplicative ramp secret sharing proposed by Chen et al. in 2008.

In this paper, a design method for the infinite impulse response (IIR) filters using the particle swarm optimization (PSO) is developed. It is well-known that the updating in the PSO tends to stagnate around local minimums due to a strong search directivity. Recently, the asynchronous digenetic PSO with nonlinear dissipative term (N-AD-PSO) has been proposed as a purpose for a diverse search. Therefore, it can be expected that the stagnation can be avoided by the N-AD-PSO. However, there is no report that the N-AD-PSO has been applied to any realistic problems. In this paper, the N-AD-PSO is applied for the IIR filter design. Several examples are shown to clarify the effectiveness and the drawback of the proposed method.

We propose an inter-cell interference coordination (ICIC) method that employs inter-cell coordinated transmission power control (TPC) based on inter-cell interference power in addition to conventional received signal power-based TPC in the cellular uplink. We assume orthogonal multiple-access as is used in 3GPP LTE. In the proposed method, an ICIC effect similar to that for conventional fractional frequency reuse (FFR) is obtained. This is achieved by coordinating the allowable inter-cell interference power level at the appropriate frequency blocks within the system bandwidth among neighboring cells in a semi-static manner. Different from conventional FFR, since all users within a cell can access all the frequency blocks, the reduction in multiuser diversity gain is abated. Computer simulation results show that the proposed method enhances both the cell-edge and average user throughput simultaneously compared to conventional universal frequency reuse (UFR) and FFR.

In this letter, we study the R-D properties of independent sources based on MSE and SSIM, and compare the bit allocation performance under the MINAVE and MINMAX criteria in video encoding. The results show that MINMAX has similar results in terms of average distortion with MINAVE by using SSIM, which illustrates the consistency between these two criteria in independent perceptual video coding. Further more, MINMAX results in lower quality fluctuation, which shows its advantage for perceptual video coding.

New target specific absorption rate (SAR) values, calculated using a proposed reference dipole antenna and the reference flat phantom, are presented for an SAR validation test at 150MHz. The reference flat phantom recommended by the International Electrotechnical Commission (IEC) standard for 150MHz requires a significant amount of liquid owing to its large size. We conduct a numerical analysis in order to reduce the size of the flat phantom. The optimum size of the flat phantom is 780 (L1) × 540 (W) × 200 (H)mm3, which is approximately a 64% reduction in volume compared to the reference flat phantom. The length of the reference dipole antenna required for the optimized flat phantom (extrapolated from the reference values at 300MHz) becomes 760mm. The calculated and measured return losses (S11) of the antenna at 150MHz are 24.1dB and 22dB, respectively. The calculated and measured results for the return loss of the dipole antenna agree well and satisfy the IEC standard (> 20dB). The target SAR values derived from the numerical analysis are 1.08W/kg for 1g of tissue and 0.77W/kg for 10g of tissue for an SAR validation test at 150MHz.

With the rapid increase of various uses of wireless communications in modern life, the high microwave and millimeter wave frequency bands are attracting much attention. However, the existing databases on above 6GHz radio-frequency (RF) electromagnetic (EM) field exposure of biological bodies are obviously insufficient. An in-vivo research project on local and whole-body exposure of rats to RF-EM fields above 6GHz was started in Japan in 2013. This study aims to perform a dosimetric design for the whole-body-average specific absorption rates (WBA-SARs) of unconstrained rats exposed to 6GHz RF-EM fields in a reverberation chamber (RC). The required input power into the RC is clarified using a two-step evaluation method in order to achieve a target exposure level in rats. The two-step method, which incorporates the finite-difference time-domain (FDTD) numerical solutions with electric field measurements in an RC exposure system, is used as an evaluation method to determine the whole-body exposure level in the rats. In order to verify the validity of the two-step method, we use S-parameter measurements inside the RC to experimentally derive the WBA-SARs with rat-equivalent phantoms and then compare those with the FDTD-calculated ones. It was shown that the difference between the two-step method and the S-parameter measurements is within 1.63dB, which reveals the validity and usefulness of the two-step technique.

This paper shows that the induced peak voltage on the short monopole antenna by the EM field radiated from a small gap discharge when the gap width was experimentally changed from 10 to 360µm was not directly proportional to the discharge voltage between the gap. It was found that the 10mm short monopole antenna induced peak voltage had a peak value between 40 and 60µm gap width.