M. Sangeetha

Performance Analysis of Downlink W-CDMA Systems in Weibull and Lognormal Fading Channels Using Chaotic Codes

In this paper, a subspace based blind channel estimation scheme for downlink W-CDMA systems using chaotic codes under Weibull and Lognormal fading channel conditions is proposed and compared with W-CDMA system using PN codes. The algorithm provides estimates of multiuser channels by exploiting the structural information of the data output. The subspace of the (data + noise) matrix contains sufficient information for unique determination of channels and, hence, the signature waveforms and signal constellations. The proposed channel estimation algorithm is also implemented for multiuser—orthogonal frequency division multiplexing (OFDM) system. Performance measures like bit error rate (BER) and root mean square error (RMSE) are plotted for Weibull and Lognormal fading channels. Signal constellations under Weibull and Lognormal channels are also plotted. Analytical and Simulation results for BER and RMSE are compared for W-CDMA system using PN codes and chaotic codes. Simulation results show that, chaos-based W-CDMA outperforms the PN-based W-CDMA in terms BER and RMSE. Simulation results of multiuser-OFDM system shows that performance is further improved when compared to the W-CDMA system.

Performance Analysis of Subspace Based Downlink Channel Estimation for W-CDMA Systems Using Chaotic Codes

This paper presents blind channel estimation for downlink W-CDMA system that employs chaotic codes and Walsh codes for spreading information bits of the multiple users. In a W-CDMA system, while transmitting over multipath channels, both intersymbol interference (ISI) as a result of Inter Chip Interference and multiple access interference (MAI) cannot be easily eliminated. Although it is possible to design multiuser detectors that suppress MAI and ISI, these detectors often require explicit knowledge of at least the desired users’ signature waveform. Earlier work focused on a subspace based channel estimation algorithm for asynchronous CDMA systems to estimate the multiple users’ symbols, where only AWGN channel was considered. In our work, we study a similar subspace-based signature waveform estimation algorithm for downlink W-CDMA systems, which use chaotic codes instead of pseudo random codes, that provide estimates of the multiuser channel by exploiting structural information of the data output at the base station. In particular, we show that the subspace of the (data+noise) matrix contains sufficient information for unique determination of channels, and hence, the signature waveforms and signal constellation. We consider Rayleigh and Rician fading channel model to quantify the multipath channel effects. Performance measures like bit error rate and root mean square error are plotted for both chaotic codes and Walsh codes under Rayleigh and Rician fading channels.

BER Performance Analysis of Short Reference Differential Chaos Shift Keying Scheme Using Various Maps Over Different Channel Conditions

In this paper, design and development of chaos-based radio system are realized using short reference differential shift keying. In this communication system, the length of chaos reference sequence is reduced to R so that the message signal frame duration reduces as compared to former DCSK scheme. The proposed system is implemented on AWR-Virtual System Simulator (VSS) tool. VSS software is a comprehensive environment for the end-to-end design and system-level simulation of the communication system. With MATLAB co-simulation, we can readily import MATLAB code into VSS for enhanced system capability. The proposed system will be studied to deduce analytical BER expression under fading channel conditions and validated with simulated and experimental results.

NR-DCSK Based Chaotic Communications in MIMO Multipath Channels

In this paper, digital chaotic communications in multiple-input–multiple-output (MIMO) wireless multipath fading channels is considered. A noise reduction-differential chaos shift keying (NR-DCSK) scheme is employed to modulate data symbols at each transmit antenna which transmits signals omni-directionally. In the transmitter side, we use β/P chaotic samples as reference sequences which is then repeated P times to generate the required reference sequence of length β. At the receiver side, a moving average filter of size P is used to reduce the noise variance of the received signal so as to enhance the system performance. The resulting filtered signal is then correlated and combined using diversity combining techniques to yield the transmitted symbol. It is shown that with spatial diversity gains, the enhancement in bit error rates (BER) of the proposed system is much better than the conventional M-DCSK based MIMO Chaotic Communication systems. Moreover, a closed-form expression for BER of the proposed system is derived over AWGN and Rayleigh fading channel conditions. Comparison of simulation results with theoretical BER expressions of additive white Gaussian noise (AWGN) and Rayleigh fading channels for various system parameters like signal to noise ratio, Spatial diversity orders, combining techniques have been carried out to test the performance enhancement of the proposed NR-DCSK based MIMO system.

Smart supply chain management using internet of things

Supply chain management (SCM) records the information about the movement of raw materials. Radio frequency identification (RFID) is the technology considered as the next promising technology in serving the positioning purpose. This paper proposes a SCM simulation platform that deals with the tracking of goods or raw materials at both indoor and outdoor environment and also to monitor the goods using IoT anywhere and also at any time. Indoor tracking of the good is accomplished through RFID tags and outdoor tracking is done through global positioning systems (GPS). XAMPP control panel is the server used here which is used to determine the location of goods and information updates on server.

Design and Development of Cost Effective Wearable Glove for Automotive Industry

In an automotive production unit considerable amount of time is spent on testing and observation. Therefore a need arises to address this issue with the help of any automation technique. In this paper, a cost effective wearable glove for monitoring automotive parameters such as temperature, flaw detection, Electro Motive Force (EMF) leakage and Direct Current (DC) measurement etc. To perform these measurements, various sensor units like temperature sensor for monitoring temperature, ultrasonic sensor for flaw detection are interfaced with the Arduino board and the monitored parameters are displayed in a graphical Liquid Crystal Display (LCD). The proposed design for wearable glove using Arduino Board enables time efficient continual monitoring of the parameters.

PN codes Vs chaotic sequences: BER comparison perspective

In this paper, we consider the BER performance of chaotic modulation schemes in Single-Input-Multiple-Output (SIMO) Nakagami fading channels. In particular, we focus on a system that employs Differential chaos Shift keying (DCSK). We consider transceiver scheme which require no channel state information at either the transmitter or the receiver. A distinct chaotic sequence is used at the transmit antenna to spread the data symbols and transmits omni directionally. At each receive antenna, the corresponding differential detection statistics is performed and these statistics are combined with maximum ratio combining for symbol detection. Simulation results show that the proposed schemes can effectively exploit spatial diversity of the underlying SIMO system. The performance of the system is evaluated for both chaotic sequence and PN sequence in terms of Bit Error Rate (BER) for various space diversity levels and average SNRs. Also, the BER performance of these systems is evaluated for various spreading code lengths.