Analysis of a Spatial Modulation System over Time-varying Rician Fading Channel with a CSI Detector

International audienceSpatial Modulation (SM) is proposed in the literature as a new Multiple-Input Multiple-Output (MIMO) transmission scheme. The advantage of the SM consists in using only one RF (Radio Frequency) chain in the transmitting end which helps to increase the energy efficiency and the performance of the transmission. The related work in the literature is mostly based on the study of the SM transmission under the simple channel models. Moreover, it is assumed that the perfect Channel State Information (CSI) is known by the receiving end. This article discusses a CSI detector for the channel estimation and analyzes the performance of the proposed system over the time-varying Rician fading channel. The ADS-Matlab co-simulation results demonstrate that the bit error rate (BER) can be kept at an acceptable level with a realistic CSI detector, and in this case the system offers better performance with a small Rician factor

New Approaches For Augmented UHF RFID Textile Yarn

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Full Duplex Spatial Modulation System Performance Depending on Self-interference Cancellation Accuracy

International audienceSpatial modulation (SM) as a new Multiple-Input Multiple-Output (MIMO) technique is based on transmitting part of the information by activating different emitting antennas. SM increases spectral efficiency and uses only one radio frequency chain. For full-duplex (FD) communication systems, self-interference (SI) is always a central problem. Therefore, combining FD and SM can drastically reduce the difficulty of Self-interference Cancellation (SIC) because of the single SI chain. A Full Duplex Spatial Modulation (FDSM) system is proposed and an active analog SIC is highlighted in this paper. Moreover, the impact of SIC accuracy on the system performance is studied. The results demonstrate that the accuracy requirement will increase as the INR (Self-interference-to-noise Ratio) increases. The FDSM system is less sensitive than the FD system in presence of high estimated error value. Furthermore, an SI detector is presented to resolve the influence of the number of detect symbols

2.4 GHz antenna array using vector modulator based active phase shifters for beamforming

International audienceThis study presents the analysis and the experimental results of a 2.4 GHz antenna array using vector modulators working as active phase shifters for beamforming. With the use of such an active phase shifter, a continuously controlled 360° phase shifting range can be achieved leading to an efficient beamforming architecture. To show the robustness of this system, a theoretical analysis is first performed in order to quantify the impact of vector modulators I/Q mismatch on the obtained gains and phase shifts. In the same way, the impact of the vector modulators noisy command voltages is also quantified by system simulations. The experimental results of the 2.4 GHz vector modulators show a maximum relative gain error close to 2.5% and an absolute phase error less than 3°. The measured 1 dB output compression point is -6 dBm. Measurements of the prototype including an array of four 'patch' antennas controlled by the vector modulators were also performed in an anechoic chamber. The results show good agreement between measured and theoretical radiation patterns

Analyse comportementale d'un circuit récupérateur d'énergie en présence de signaux complexes

International audienceThis paper shows the incidence of the modulation scheme and of the input power on the RF to DC rectifier conversion efficiency. A commercial energy harvesting (EH) P21XXCSR-EVB evaluation board from Powercast Corporation is used as measurement target and several waveforms are employed to evaluate the rectification efficiency. With a continuous wave as reference, QPSK, QAM and OFDM waveforms usage demonstrates that digital modulated signals can lead to a better efficiency. Thus, by selecting a high peak to average power ratio (PAPR), and under certain conditions, the performances of the energy harvesting circuit are enhanced.Cet article montre l'incidence du choix de la modulation et de la puissance du signal d'entrée sur l'efficacité d'une conversion RF-DC d'un circuit récupérateur d'énergie. Un circuit commercial de la société Powercast, le convertisseur P21XXCSR-EVB, est utilisé comme système récupérateur d'énergie RF et plusieurs formes d'onde sont générées afin de tester l'efficacité du redresseur. Avec comme référence une onde sinusoïdale, l'utilisation des formes d'ondes de type QPSK, QAM et OFDM montrent qu'un signal modulé permet d'atteindre une meilleure efficacité. Ainsi, en choisissant un rapport PAPR élevé, et sous certaines conditions, les performances du redresseur sont améliorées

Driver's warning notifications by using FM RDS technology

International audienceIn this paper, the use of Software Defined Radio (SDR) transceivers for broadcasting drivers' warning notifications is tackled. More precisely, by employing the Radio Data System (RDS) protocol of a local Frequency Modulation (FM) transmission, road traffic's dangerous areas (rail crossing, unmarked crossroads, etc.) are announced. The code of a warning message is broadcasted in the close vicinity of the dangerous area and, at the receiver side, a corresponding image is displayed on the car's tablet PC. In order to study the coexistence of such kind of transmissions with the regional or national ones, the performance in terms of bit error rate (BER) with respect to the difference between the two received power levels is studied. Then, based on a simplified channel model, this paper gives a method to estimate the local FM transmission range, able to cover the dangerous area without transmission errors on the RDS part

A 2.4 GHz active phase shifter architecture for smart antennas control

International audienceThis paper aims at developing the bases of a smart radio-communication prototype, able to modify the radiation patterns, both on emission and reception, according to the needs of the communication. Smart antenna is a well-known concept, allowing to increase the quality of the transmission and spectral efficiency. To control the radiation patterns, algorithms used in smart antenna techniques require precise amplitudes and phases generation. In this paper, vector modulators working as active phase shifters will be used in order to synthesize such amplitudes and phases. A theoretical analysis will be performed in order to quantify the impact of vector modulators mismatches on the synthesized amplitudes and phases. Furthermore, measurements of radiation patterns generated by a prototype at 2.4 GHz will be presented

Theoretical BER Evaluation of Passive RFID Tag-To-Tag Communications

International audienceThe concept of UHF RFID passive tag-to-tag communication has been introduced and opens new promising perspectives in the field of Internet-of-Things. This concept enables two powerless tags to exchange information using an external source. Moreover, a simulation framework has been proposed as a tool allowing the performance evaluation of tag-to-tag radio links in terms of Bit Error Rate (BER). The aim of this paper is to provide a theoretical framework for BER estimation. The theoretical framework takes into account various parameters such as modulation rate, receivers topology and the electromagnetic coupling of the tags. Furthermore, in order to validate the obtained results, they are compared with the ones obtained by realistic simulations

Impact of Receiver Non-idealities on a Full Duplex Spatial Modulation System Performance

International audienceIn this paper, we analyze, for the first time, the performance of a full-duplex system combined with spatial modulation technique in presence of the receiver non-idealities. IQ imbalance and phase noise are the two radio front-end mismatch factors that have been considered. The impact of the IQ imbalance on the bit error rate (BER) performance of the full-duplex spatial modulation (FDSM) system under different noise levels is investigated. An estimator has also been proposed for the self-interference cancellation (SIC) after the imperfect receiver. The results show that IQ imbalance does not significantly reduce system BER performance at low signal-to-noise ratios. Moreover, it is shown that the proposed estimator is able to maintain the system at an acceptable BER

Full Duplex Spatial Modulation System in presence of IQ imbalance

International audienceThe combination of the spatial modulation (SM) and of the full duplex (FD) is a challenging research direction because it brings high spectral efficiency and even energy consumption reduction because of the use of a unique radio frequency (RF) receiving chain. This paper presents a full-duplex spatial modulation (FDSM) system over the Rician fading channel. A least-square self-interference (SI) esti-mator is implemented for the self-interference cancellation (SIC). Moreover, the impact of IQ imbalance on the bit error rate (BER) performance is analyzed. The obtained results show that the proposed estimator can reduce SI at a low level. The system is more sensitive to the IQ imbalance under low noise environment