It has been shown that an inverter-fed power line is a feasible medium for the transmission of modulated information. The communication channel includes the feeder cable terminated by two loads: the motor and the inverter. This link is a suitable alternative for the sensor cabling between motors and inverters in motor control and diagnostic applications. The use of the motor power cable in the speed feedback induction motor control application and the modelling of the formed communication channel are presented and discussed in this paper. 相似文献
This paper deals with the performance of a compact dual diversity receiver. For this study we assume that the channel is characterized by a flat Rayleigh fading and that the incoming waves can be described by a Gaussian angular power distribution. The performance of a maximal-ratio-combiner in a correlated Rayleigh fading is given. These expressions are simplified and studied for the case of a dual diversity receiver. The influence of the mutual coupling between the sensors is taken into account using a simplified model. The results are compared with results obtained from realistic antenna simulations. 相似文献
A multisensor decision feedback equaliser based on the minimum mean squared error (MMSE) criterion is studied. The superiority of the performance of the multisensor equaliser is shown by simulation of a whole communication system in which the adaptive equaliser is incorporated. The recursive least squares (RLS) algorithm is used to update the coefficients. From the results obtained for a time-varying urban terrain channel model, the extremely interesting tracking capability of the multisensor equaliser is shown 相似文献
This paper describes a digital receiver for radiomobile communications. The adaptive filter is a purely spatial filter. The used criterion is the minimisation of a mean square error between the array output signal and a reference signal. The reference signal is generated using the demodulator results. No learning sequence is required. The algorithm is digitally implemented and it uses a direct matrix inversion algorithm. The performance study, using simulation and experimental results, shows tracking properties, jammers cancelling and multivath correction. 相似文献
Binary offset carrier modulation is applied in several signals of the global navigation satellite system (GNSS). It enhanced the robustness of GNSS against the impact of multipath and make the compatibility of GNSS better. However, it has the main drawback of potentially giving biased measurements in acquisition and tracking. The technique we proposed is based on linear fitting with multi-correlator to accomplish unambiguous tracking. The coefficient of each correlator was deduced in this paper. The theoretical analysis and simulation results indicate that the proposed method can performs well on multipath and thermal noise. 相似文献
Time synchronization is crucial for the implementation of cooperative communication in wireless sensor networks. In this paper,
we explore the effect of synchronization error on cooperative communication utilizing distributed Alamouti code. The analysis
and simulation results show that small synchronization error has negligible effect on bit error rate (BER) performance. In
order to synchronize the distributed sensor nodes within an acceptable error, we propose a physical layer synchronization
scheme. This scheme consists of an initial synchronization of the cooperative transmitters, synchronization error estimation
at the cooperative receiver and finally a feedback phase. A maximum likelihood method is proposed to make the synchronization
error estimation. It achieves better performance than the matched filter method at the price of moderate increase in computational
complexity and memory space. Two strategies after synchronization error estimation have been analyzed. They provide better
BER performance in the existence of initial synchronization error. They are practical to be implemented in the sensor nodes
before the Alamouti decoding. 相似文献
Presently employed underwater communication systems suffer from issues such as low data rates and short communication ranges. In this paper, a novel hybrid underwater intelligent communication system is proposed and modeled to address both issues. The proposed system provides higher data rate, longer communication range and secure data transmission by employing optical fiber, underwater free space optics (UFSO) and free space optics (FSO). An intelligent routing mechanism governed by Tabu search (TS) algorithm is used for optical path selection based on data traffic, data rate and communication length to maintain a desired quality of service (QoS) while ensuring security of data transmission. For, modeling, optical fiber channel, priority aware (PA) scheduling algorithm for packet-switched optical network (PSON) for data transmission is used whereas for the FSO channel modeling, orthogonal frequency division multiplexing (OFDM) and On–Off Keying (OOK) are used.To simulate underwater turbulent conditions for UFSO channel, scintillation model with gamma-gamma distribution (GGD) is applied. A data rate of 10 Gbps with BER of 10–9 has been achieved for communication ranges of 140 and 200 m for the cases of turbulent and non-turbulent water conditions. In each of the cases, QoS meeting IEEE standards is ensured.
This paper investigates the performance of a compact space-time diversity receiver for mobile communication systems. Expressions for the bit error rate and outage meanSnr are derived as a function of the channel covariance matrix. These results define the sensitivity of the performance of such a receiver to the environment (fading characteristics and angular spread) and the antenna array (geometry and coupling). Furthermore, these results are validated for a practical antenna system. 相似文献
This paper analyzes the performance of systems with dual-polarized antennas in correlated Nakagami-m fading channels as a function of envelope correlation and cross-polarization discrimination by means of the characteristic function of the instantaneous post-maximal ratio combining (MRC) signal-to-noise ratio (SNR). Systems of interest include systems with receive polarization diversity and systems with transmit and receive polarization diversity employing Alamouti space-time code. The expressions for the average symbol error probability as a function of SNR assuming no power control, and the expressions for the average required transmit power to achieve the constant desired post-MRC SNR assuming perfect fast power control, are derived. Finally, a comparison between analytical and simulation results is used to validate the analysis. 相似文献