Journal articles: 'Shaped Offset Quadrature Phase Shift Keying'

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Zou, Ning, Benxiong Huang, and Zhengguang Xu. "Shaped offset quadrature phase shift keying (SOQPSK) modulation scheme and its application in optical wavelength-division multiplexed (DWDM) transmission." Optical Fiber Technology 19, no. 5 (October 2013): 400–404. http://dx.doi.org/10.1016/j.yofte.2013.05.002.

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Cai, Zhikuang, Mingmin Shi, Shanwen Hu, and Zixuan Wang. "A 2.4 GHz 2.9 mW Zigbee RF Receiver with Current-Reusing and Function-Reused Mixing Techniques." Electronics 9, no. 4 (April 24, 2020): 697. http://dx.doi.org/10.3390/electronics9040697.

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This study presents a low-power Zigbee receiver with a current-reusing structure and function-reused mixing techniques. To reduce the overall power consumption, a low noise amplifier (LNA) and a power amplifier (PA) share the biasing current with a voltage-controlled oscillator (VCO) in the receiving (RX) mode and transmitting (TX) mode, respectively. The function-reused mixer reuses the radio frequency trans-conductance (RF gm) stage to amplify the down-converted intermediate frequency (IF) signal, obtaining a free IF gain without extra power consumption. A peak detector circuit detects the receiving signal strength and auto-adjusts the biasing current to save power when a strong signal strength is detected. Meanwhile, the peak detector helps to provide a coarse gain control as part of the auto-gain-control function. As part of the IF gain range is shared by the multiple-feedback (MFB) low-pass filter, the number of programmable-gain IF amplifier stages can be reduced, which also means a decrease in power consumption. A prototype of this wireless sensor network (WSN) receiver was designed and fabricated using the TSMC 130 nm CMOS process under a supply voltage of 1 V. The entire receiver realizes a noise figure (NF) of 3.5 dB and a receiving sensitivity of −90 dBm for the 0.25 Mbps offset quadrature phase shift keying (O-QPSK) signal with a power consumption of 2.9 mW.

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Stanley, Alphyn, and R. K. Sharma. "Very Large Scale Integrated-Circuit Architecture for Offset Quadrature Phase Shift Keying Modulation Using Offset Generator." Sensor Letters 17, no. 11 (November 1, 2019): 884–87. http://dx.doi.org/10.1166/sl.2019.4142.

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This work presents an architecture for Offset Quadrature Phase Shift Keying (OQPSK) using an Offset generator. The Offset generator generates symbol patterns such that there is a maximum phase shift of ±90° only between the symbols, unlike the Quadrature Phase Shift Keying (QPSK) modulator which has a maximum of ±180° phase shift. Here the effort of designing an Offset generator, which can be embedded onto QPSK modulator to generate OQPSK with minimum combinational logic, has been discussed. Whenever the input symbols to the Offset generator varies in phase with a ±180° in constellation, it generates an intermediate symbol which differs only in ±90° with the previous one. Then it continues to give out the original symbol to be transmitted. This follows the exact OQPSK technology while it doesn't follow the conventional generation method of OQPSK modulation which provides an offset between the even and odd bit patterns of the symbols to be transmitted. The architecture is modelled using Verilog HDL and the functionality is validated from the simulation result.

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Zhang, Fangzheng, Jian Wu, Yan Li, and Jintong Lin. "Fiber nonlinear tolerance comparison between 112 Gb/s coherent transmission systems using quadrature-phase-shift-keying, offset quadrature-phase-shift-keying, and minimum-shift-keying formats." Optical Engineering 51, no. 10 (October 1, 2012): 105001–1. http://dx.doi.org/10.1117/1.oe.51.10.105001.

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Ge, Qian, Qian Wang, Xiao Yan, and Ling He. "Algorithms for Automatic Modulation Recognition in Wireless Monitoring Applications." Applied Mechanics and Materials 241-244 (December 2012): 1772–78. http://dx.doi.org/10.4028/www.scientific.net/amm.241-244.1772.

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The paper proposes an automatic modulation recognition scheme based on instantaneous features of intercepted signals. The modulation classifier can discriminate modulations such as Amplitude Modulation (AM), Double Side Band (DSB), Single Side Band (SSB), Frequency Modulation (FM), M-ary Amplitude Shift Keying (M-ASK), M-ary Frequency Shift Keying (M-FSK), M-ary Phase Shift Keying (M-PSK) and M-ary Quadrature Amplitude Modulation (M-QAM) without any prior information. The scheme is with simple structure, computationally simpler, and suitable for real-time processing. And the recognition parameters are anti-noise, and insensitive to frequency offset, phase offset and timing error. To evaluate the performance of the scheme, several experiments with signals in Additive White Gaussian Noise (AWGN) channel were carried out in the MATLAB by varying the values of both the main modulation parameters and the signal-to-noise ratios (SNRs). The results show that the approach can achieve high recognition accuracy even at low SNR.

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Al- Azzawi, Fatima faydhe, Faeza Abas Abid, and Zainab faydhe Al-Azzawi. "Performance Comparison between DPSK and OQPSK modulation approaches in multi environments channels with Matlab Simulink models." Wasit Journal of Engineering Sciences 7, no. 1 (April 15, 2019): 30–39. http://dx.doi.org/10.31185/ejuow.vol7.iss1.112.

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Phase shift keying modulation approaches are widely used in the communication industry. Differential phase shift keying (DPSK) and Offset Quadrature phase shift keying (OQPSK) schemes are chosen to be investigated is multi environment channels, where both systems are designed using MATLAB Simulink and tested. Cross talk and unity of signals generated from DPSK and OQPSK are examined using Cross-correlation and auto-correlation, respectively. In this research a proposed system included improvement in bit error rate (BER) of both systems in the additive white Gaussian Noise (AWGN) channel, by using the convolutional and block codes, by increasing the ratio of energy in the specular component to the energy in the diffuse component (k) and the diversity order BER in the fading channels will be improved in both systems.

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Shantha Selva Kumari, R., and K. Seyatha. "Performance evaluation of hybrid modulation techniques for high speed radio over fiber communication system." International Journal of Modern Physics C 30, no. 09 (September 2019): 1950070. http://dx.doi.org/10.1142/s0129183119500700.

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In Radio over Fiber (RoF) technology, the optical network capacity is integrated with the wireless network. The main objective of this work is to enhance the performance behavior of optical fiber communication system in terms of BER, Received Power and Q-Factor. The proposed combined modulation technologies, such as Pulse Amplitude Frequency Modulation (PAFM), Differential Phase Shift Keying Amplitude Modulation (DPSKA), Offset Quadrature Phase Shift Keying Amplitude Modulation (OQPSKA), Quadrature Amplitude Frequency Modulation (QAFM), Frequency Phase Modulation (FPM) and Pulse Amplitude Phase Modulation (PAPM), are used to meet this objective. The input data are used for modulating the electrical carrier signal with a frequency of 250 and 255[Formula: see text]GHz. This hybrid modulation technique obtained the minimum BER of about [Formula: see text] in FPM technique. The maximum Q-Factor of 33 is obtained in QAFM technique. The obtained maximum received power is 0.79[Formula: see text]mW in OQPSKA technique.

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Spalvieri, Arnaldo, and Maurizio Magarini. "Wiener's Loop Filter for PLL-Based Carrier Recovery of OQPSK and MSK-Type Modulations." Research Letters in Communications 2008 (2008): 1–4. http://dx.doi.org/10.1155/2008/235761.

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This letter considers carrier recovery for offset quadrature phase shift keying (OQPSK) and minimum shift keying-type (MSK-type) modulations based on phase-lock loop (PLL). The concern of the letter is the optimization of the loop filter of the PLL. The optimization is worked out in the light of Wiener's theory taking into account the phase noise affecting the incoming carrier, the additive white Gaussian noise that is present on the channel, and the self-noise produced by the phase detector. Delay in the loop, which may affect the numerical implementation of the PLL, is also considered. Closed-form expressions for the loop filter and for the mean-square error are given for the case where the phase noise is characterized as a first-order process.

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Li, Xueliang, Tianwen Geng, Yucong Gu, Ruotong Tian, and Shijie Gao. "Compensation for In-Phase/Quadrature Phase Mismatch in Coherent Free-Space Optical QPSK Communication Systems." Applied Sciences 11, no. 6 (March 12, 2021): 2543. http://dx.doi.org/10.3390/app11062543.

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The Gram–Schmidt orthogonalization procedure (GSOP) and Löwdin symmetric orthogonalization procedure (SYOP) are the two mainstream algorithms for the compensation of phase mismatch in an imperfect optical 90° hybrid. In this paper, we put forward an algorithm switching orthogonalization procedure (ASOP) according to the quality of in-phase and quadrature signals based on the Q value of the eye diagram with less computation. If the quality of the in-phase and quadrature signals has a significant difference, we use the GSOP and select the signal branch with better quality as the initial reference vector for orthogonalization. If they are of about the same quality, then we use the SYOP. We present computer simulations for a coherent free-space optical (FSO) quadrature phase-shift keying (QPSK) communication system and demonstrate the system improvement that can be achieved using the ASOP. Finally, we also show that the proposed ASOP scheme can contribute to the frequency offset and phase estimation of the FSO system in the environment of atmospheric turbulence.

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Yonis, A. Z. "Influence of low power consumption on IEEE 802.15.4 in wireless networks performance." Bulletin of Electrical Engineering and Informatics 9, no. 1 (February 1, 2020): 205–11. http://dx.doi.org/10.11591/eei.v9i1.1678.

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IEEE 802.15.4 standard defines both media access control (MAC) and physical (PHY) layer protocols for low power consumption, low peak data rate, and low cost applications. Nowadays the most important feature of IEEE 802.15.4 is maximizing battery life. This paper is focusing how to achieve low average power consumption through assuming that the amount of data transmitted is short and that it is transmitted infrequently so as to keep a low duty cycle. The outcomes demonstrate that the phase shift estimation of Offset quadrature phase-shift keying (OQPSK) modulation has no impact on bit error rate (BER) if it is identical in the transmitter as same as in the receiver.

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Kumar, Atul, Maurizio Magarini, Hem Dutt Joshi, and Rajiv Saxena. "Exact SER Analysis of DFrFT-Based QPSK OFDM System over Frequency Selective Rayleigh Fading Channel with CFO." Journal of Computer Networks and Communications 2016 (2016): 1–7. http://dx.doi.org/10.1155/2016/2804507.

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We present the exact symbol error rate (SER) expression for quadrature phase shift keying (QPSK) modulation in frequency selective Rayleigh fading channel for discrete fractional Fourier transform- (DFrFT-) based orthogonal frequency division multiplexing (OFDM) system in the presence of carrier frequency offset (CFO). The theoretical result is confirmed by means of Monte Carlo simulations. It is shown that the performance of the proposed system, at different values of the DFrFT angle parameter “α,” is better than that of OFDM based on discrete Fourier transform.

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Zhao, Na, Qing Chang, Hao Wang, and Zhibo Zhang. "An Unbalanced QPSK-Based Integrated Communication-Ranging System for Distributed Spacecraft Networking." Sensors 20, no. 20 (October 14, 2020): 5803. http://dx.doi.org/10.3390/s20205803.

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The spacecraft tracking telemetering and command (TT&C) system plays an essential role in celestial and terrestrial networks, requiring relative ranging and communication, particularly in satellite formation flying networks and distributed spacecraft networks. To achieve precious ranging and high-data-rate communication in a Master/Slave satellite architecture, an integrated communication-ranging system (ICRS) is introduced. ICRS is based on the inter-satellite spread spectrum ranging and spread/non-spread spectrum communication modulated by unbalanced quadrature phase shift keying (UQPSK). In both uplink and downlink, the in-phase (I) branches and the quadrature (Q) branches undertake the tasks of ranging and communication, respectively. In addition, a global navigation satellite system (GNSS) like signal is adopted in I branches for the sake of better ranging accuracy, and binary phase shift keying (BPSK) modulation is employed in Q branches for a higher data rate. Therefore, the key point of the ICRS design is the power resource allocation between two branches via the selection of a suitable power distribution factor (PWDF). Simulation results demonstrate the good performance of the proposed approach in ranging error and bit error rate (BER). In addition, a reasonable PWDF is recommended. Furthermore, the influence of clock offset is also taken into consideration.

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Jiang, Wen, Yanfu Yang, Qun Zhang, Yunxu Sun, Kangping Zhong, Xian Zhou, and Yong Yao. "Application of Kalman filter in frequency offset estimation for coherent optical quadrature phase-shift keying communication system." Optical Engineering 55, no. 9 (September 2, 2016): 096102. http://dx.doi.org/10.1117/1.oe.55.9.096102.

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Liu, Zilong, Kexian Gong, Peng Sun, Jicai Deng, Kunheng Zou, and Linlin Duan. "OQPSK Synchronization Parameter Estimation Based on Burst Signal Detection." Electronics 10, no. 1 (January 2, 2021): 69. http://dx.doi.org/10.3390/electronics10010069.

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The fast estimation of synchronization parameters plays an extremely important role in the demodulation of burst signals. In order to solve the problem of high computational complexity in the implementation of traditional algorithms, a synchronization parameter (frequency offset, phase offset, and timing error) estimation algorithm based on Offset Quadrature Phase Shift Keying (OQPSK) burst signal detection is proposed in this article. We first use the Data-Aided (DA) method to detect where the burst signal begins by taking the segment correlation between the receiving signals and the known local Unique Word (UW). In the sequel, the above results are adopted directly to estimate the synchronization parameters, which is obviously different from the conventional algorithms. In this way, the complexity of the proposed algorithm is greatly reduced, and it is more convenient for hardware implementation. The simulation results show that the proposed algorithm has high accuracy and can track the Modified Cramer–Rao Bound (MCRB) closely.

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Rondeau, Christopher M., J. Addison Betances, and Michael A. Temple. "Securing ZigBee Commercial Communications Using Constellation Based Distinct Native Attribute Fingerprinting." Security and Communication Networks 2018 (July 11, 2018): 1–14. http://dx.doi.org/10.1155/2018/1489347.

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This work provides development of Constellation Based DNA (CB-DNA) Fingerprinting for use in systems employing quadrature modulations and includes network protection demonstrations for ZigBee offset quadrature phase shift keying modulation. Results are based on 120 unique networks comprised of seven authorized ZigBee RZSUBSTICK devices, with three additional like-model devices serving as unauthorized rogue devices. Authorized network device fingerprints are used to train a Multiple Discriminant Analysis (MDA) classifier and Rogue Rejection Rate (RRR) estimated for 2520 attacks involving rogue devices presenting themselves as authorized devices. With MDA training thresholds set to achieve a True Verification Rate (TVR) of TVR = 95% for authorized network devices, the collective rogue device detection results for SNR ≥ 12 dB include average burst-by-burst RRR ≈ 94% across all 2520 attack scenarios with individual rogue device attack performance spanning 83.32% < RRR < 99.81%.

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Zhou, Xiao, Chengyou Wang, and Ruiguang Tang. "Channel Estimation Based on IOTA Filter in OFDM/OQPSK and OFDM/OQAM Systems." Applied Sciences 9, no. 7 (April 7, 2019): 1454. http://dx.doi.org/10.3390/app9071454.

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In this paper, we present a study of bit error rate (BER) for orthogonal frequency division multiplexing/offset quadrature phase shift keying (OFDM/OQPSK) and OFDM/offset quadrature amplitude modulation (OQAM) systems with an isotropic orthogonal transfer algorithm (IOTA) filter. The novel noise suppression method based on an IOTA filter is proposed to reduce the error of channel estimation caused by additive white Gaussian noise (AWGN). The OFDM/OQPSK and OFDM/OQAM systems do not insert the guard interval (GI) and pilots in the signal frames, thus they possess transmission efficiency. An analysis was carried out for convolutional coded OFDM/OQPSK and OFDM/OQAM systems in Rayleigh fading channels with generator polynomials and constraint lengths. Compared with conventional OFDM/QPSK and OFDM/QAM systems with the insertion of comb-type pilots, the proposed IOTA filter-based channel estimation method can provide significant energy per bit to time-varying noise power spectral density ratio gains over time and frequency-selective propagation Rayleigh fading channels in OFDM/OQPSK and OFDM/OQAM systems.

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Yang, Zhihua, Huiyuan Li, Qinyu Zhang, Jiao Qin, Yunhe Li, and Bin Cao. "Low-density parity-check-Feher quadrature phase shift keying signalling with frequency-offset compensated iterative demodulation and decoding algorithm." IET Communications 8, no. 13 (September 5, 2014): 2264–71. http://dx.doi.org/10.1049/iet-com.2013.0790.

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Makarov, Sergey B., Mingxin Liu, Anna S. Ovsyannikova, Sergey V. Zavjalov, ILya Lavrenyuk, Wei Xue, and Yidong Xu. "A Reduction of Peak-to-Average Power Ratio Based Faster-Than-Nyquist Quadrature Signals for Satellite Communication." Symmetry 13, no. 2 (February 20, 2021): 346. http://dx.doi.org/10.3390/sym13020346.

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The increase in the throughput of digital television and radio broadcasting (DVB) channels can be achieved due to application of signals with a compact spectrum and a relatively small peak-to-average power ratio (PAPR). The reason is the usage of traveling wave tubes (TWT) for amplifying and transmitting signals from a satellite repeater in DVB-S2X systems. At the same time, given that the bandwidth allocated for transmission should be used as efficiently as possible, a high reduction rate of out-of-band emissions level is required. The most effective solution in this direction is the transition to spectrum-economic signals, such as optimal Faster-Than-Nyquist (FTN) signals, which can provide a certain reduction rate of the out-of-band emissions level and minimum acceptable PAPR. This article proposes a method for obtaining optimal FTN pulses, which have symmetry in time domain, with specified PAPR and reduction rate of out-of-band emissions for the quadrature phase shift keying (QPSK) and offset quadrature phase shift keying (OQPSK). The possibility of synthesizing signals with OQPSK modulation is presented theoretically for the first time. Optimal FTN signals can provide PAPR reduction by at most 3 dB and outperform known root raised cosine (RRC) pulses. The simulation model adopts an architecture for quadrature generation of optimal FTN signals with OQPSK modulation with blocks for adjustable pre-amplification, clipping, and power amplification. The proposed signals can be used to increase the spectral and energy efficiencies of satellite broadcasting systems, such as DVB-S2/S2X, as well as low-rate return channels of interactive broadcasting systems with a frequency resource shortage.

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Kadhum, Ekhlas, and Russul Haitham. "Performance Analysis of IEEE 802.15.4 Transceiver System under Adaptive White Gaussian Channel." International Journal of Electrical and Computer Engineering (IJECE) 8, no. 6 (December 1, 2018): 4184. http://dx.doi.org/10.11591/ijece.v8i6.pp4184-4196.

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Zigbee technology has been developed for short range wireless sensor networks and it follows IEEE 802.15.4 standard. For such sensors, several considerations should be taken including; low data rate and less design complexity in order to achieve efficient performance considering to the transceiver systems. This research focuses on implementing a digital transceiver system for Zigbee sensor based on IEEE 802.15.4. The system is implemented using offset quadrature phase shift keying (OQPSK) modulation technique with half sine pulse-shaping method. Direct conversion scheme has been used in the design of Zigbee receiver in order to fulfill the requirements mentioned above. System performance is analyzed considering to BER when it encountered adaptive white Gaussian noise (AWGN), besides showing the effect of using direct sequence spread spectrum (DSSS) technique.

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Chen, Bo, Yangyu Fan, Zhou Tian, Wuying Wang, Bochao Kang, Wei Jiang, and Yongsheng Gao. "An Ultra-Wideband Microwave Photonic Channelized Receiver with Zero-IF Architecture." Applied Sciences 10, no. 1 (December 19, 2019): 30. http://dx.doi.org/10.3390/app10010030.

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A scheme for realizing a zero-intermediate frequency (IF) channelized receiver using a dual-polarization quadrature phase-shift keying (DP-QPSK) modulator and a narrow-band optical filter is proposed. The channelized system only requires one optical frequency comb to achieve zero-IF multi-channel reception of wideband signals, and the spacing of the optical frequency comb only needs to be equal to the sub-channel width, which is very easy to implement. It is found that using photonic IQ demodulation and balanced detection and reception technology can not only eliminate many disadvantages of the traditional zero-IF receiver, including local oscillator (LO) leakage, direct current (DC) offset, even-order distortion, and in-phase/quadrature (I/Q) imbalance, but also reduce the bandwidth and sample rate of the analog-to-digital converter (ADC). It is theoretically proven that the radio frequency (RF) signal with a bandwidth of 3 GHz can be divided into five sub-channels with a bandwidth of 600 MHz and finally demodulated to I/Q basebands, which are also verified with simulation.

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Louet, Yves, Rami Othman, and Alexandre Skrzypczak. "A Soft-Output STBC Decoder for Aeronautical Telemetry." Journal of Telecommunications and Information Technology 1 (March 31, 2020): 13–20. http://dx.doi.org/10.26636/jtit.2020.138319.

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Alamouti encoding is a well-known space time block encoding technique used to improve the received signal quality in Rayleigh fading channels. In aeronautical telemetry, this encoding technique is applied to shaped oﬀset quadrature phase shift keying tier generation (SOQPSK-TG) modulation in order to handle the two-antenna issue. It is provided for in telemetry-related IRIG standards. In this paper, we propose a unique decoding architecture for Alamouti-encoded SOQPSK-TG signals, taking advantage of pulse amplitude modulation decomposition with soft and hard outputs. We exploit this result to obtain a Viterbi algorithm (VA) for hard decoding and a soft output Viterbi algorithm (SOVA) for soft and hard decoding, with a twofold beneﬁt: operation using one trellis structure, unlike decoders that are based on the 8-waveforms cross-correlated trellis-coded quadrature modulation (XTCQM) approximation, and very attractive bit error rate performance, as well as a complexity trade-oﬀ

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Wang, Kaiyu, Zhiming Song, Xianwei Qi, Qingxin Yan, and Zhenan Tang. "FPGA-Based Implementation of All-Digital QPSK Carrier Recovery Loop Combining Costas Loop and Maximum Likelihood Frequency Estimator." International Journal of Reconfigurable Computing 2014 (2014): 1–15. http://dx.doi.org/10.1155/2014/502942.

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This paper presents an efficient all digital carrier recovery loop (ADCRL) for quadrature phase shift keying (QPSK). The ADCRL combines classic closed-loop carrier recovery circuit, all digital Costas loop (ADCOL), with frequency feedward loop, maximum likelihood frequency estimator (MLFE) so as to make the best use of the advantages of the two types of carrier recovery loops and obtain a more robust performance in the procedure of carrier recovery. Besides, considering that, for MLFE, the accurate estimation of frequency offset is associated with the linear characteristic of its frequency discriminator (FD), the Coordinate Rotation Digital Computer (CORDIC) algorithm is introduced into the FD based on MLFE to unwrap linearly phase difference. The frequency offset contained within the phase difference unwrapped is estimated by the MLFE implemented just using some shifter and multiply-accumulate units to assist the ADCOL to lock quickly and precisely. The joint simulation results of ModelSim and MATLAB show that the performances of the proposed ADCRL in locked-in time and range are superior to those of the ADCOL. On the other hand, a systematic design procedure based on FPGA for the proposed ADCRL is also presented.

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Hamza, Ekhlas K., and Russul H. Hadi. "Implementation of Transmitter Zigbee System based on Wireless Sensor Network of IEEE 802.15.4 Standard." Al-Khwarizmi Engineering Journal 13, no. 3 (September 30, 2017): 38–45. http://dx.doi.org/10.22153/kej.2017.03.002.

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Abstract Zigbee is considered to be one of the wireless sensor networks (WSNs) designed for short-range communications applications. It follows IEEE 802.15.4 specifications that aim to design networks with lowest cost and power consuming in addition to the minimum possible data rate. In this paper, a transmitter Zigbee system is designed based on PHY layer specifications of this standard. The modulation technique applied in this design is the offset quadrature phase shift keying (OQPSK) with half sine pulse-shaping for achieving a minimum possible amount of phase transitions. In addition, the applied spreading technique is direct sequence spread spectrum (DSSS) technique, which has the effect in getting better performance for the transmitter system in multipath environments. The system is developed through the use of MATLAB/Simulink to show the performance of the proposed system in response to the appliy modulation technique. Keywords: DSSS technique, IEEE 802.15.4, MSK, OQPSK, Zigbee.

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Muñoz, Jonathan, Tengfei Chang, Xavier Vilajosana, and Thomas Watteyne. "Evaluation of IEEE802.15.4g for Environmental Observations." Sensors 18, no. 10 (October 15, 2018): 3468. http://dx.doi.org/10.3390/s18103468.

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IEEE802.15.4g is a low-power wireless standard initially designed for Smart Utility Networks, i.e., for connecting smart meters. IEEE802.15.4g operates at sub-GHz frequencies to offer 2–3× longer communication range compared to its 2.4 GHz counterpart. Although the standard offers 3 PHYs (Frequncy Shift Keying, Orthogonal Frequency Division Multiplexing and Offset-Quadrature Phase Shift Keying) with numerous configurations, 2-FSK at 50 kbps is the mandatory and most prevalent radio setting used. This article looks at whether IEEE802.15.4g can be used to provide connectivity for outdoor deployments. We conduct range measurements using the totality of the standard (all modulations with all further parametrization) in the 863–870 MHz band, within four scenarios which we believe cover most low-power wireless outdoor applications: line of sight, smart agriculture, urban canyon, and smart metering. We show that there are radio settings that outperform the “2-FSK at 50 kbps” base setting in terms of range, throughput and reliability. Results show that highly reliable communications with data rates up to 800 kbps can be achieved in urban environments at 540 m between nodes, and the longest useful radio link is obtained at 779 m. We discuss how IEEE802.15.4g can be used for outdoor operation, and reduce the number of repeater nodes that need to be placed compared to a 2.4 GHz solution.

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Tuset-Peiró, Pere, Francisco Vázquez-Gallego, Jonathan Muñoz, Thomas Watteyne, Jesus Alonso-Zarate, and Xavier Vilajosana. "Experimental Interference Robustness Evaluation of IEEE 802.15.4-2015 OQPSK-DSSS and SUN-OFDM Physical Layers for Industrial Communications." Electronics 8, no. 9 (September 18, 2019): 1045. http://dx.doi.org/10.3390/electronics8091045.

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In this paper, we experimentally evaluate and compare the robustness against interference of the OQPSK-DSSS (Offset Quadrature Phase Shift Keying-Direct Sequence Spread Spectrum) and the SUN-OFDM (Smart Utility Network-Orthogonal Frequency Division Multiplexing) physical layers, as defined in the IEEE 802.15.4-2015 standard. The objective of this study is to provide a comprehensive analysis of the impact that different levels of interference produce on these modulations, in terms of the resulting PDR (Packet Delivery Ratio) and depending on the length of the packet being transmitted. The results show that the SUN-OFDM physical layer provides significant benefits compared to the ubiquitous OQPSK-DSSS in terms of interference robustness, regardless of the interference type and the packet length. Overall, this demonstrates the suitability of choosing the SUN-OFDM physical layer when deploying low-power wireless networks in industrial scenarios, especially taking into consideration the possibility of trading-off robustness and spectrum efficiency depending on the application requirements.

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Shi, Congyu, Gaoyuan Zhang, Haiqiong Li, Congzheng Han, Jie Tang, Hong Wen, Longye Wang, and Dan Wang. "Reduced-Complexity Multiple-Symbol Detection of O-QPSK Signals in Smart Metering Utility Networks." Electronics 9, no. 12 (December 2, 2020): 2049. http://dx.doi.org/10.3390/electronics9122049.

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In this work, an implementation-friendly multiple-symbol detection (MSD) scheme is proposed for the IEEE 802.15.4g offset quadrature phase shift keying (O-QPSK) receivers over the slow fading channel. The full MSD scheme presents better detection performance than the symbol-by-symbol detection (SBSD) scheme, yet its complexity increases exponentially as the observation window length increases. We introduce a simplified MSD scheme based on two powerful strategies. We first seek the optimal and suboptimal decisions in each symbol position with the standard SBSD procedure. Then, the aforementioned optimal and suboptimal decisions instead of all candidates are jointly searched with the standard MSD procedure. That is, only the most and second most reliable candidates in each symbol position are selected to participate in the final detection. The simulation results demonstrate that the new MSD scheme can achieve more encouraging energy gain than the SBSD scheme, while the high complexity of full MSD is also effectively reduced. A more legitimate compromise between detection performance and complexity is thus accomplished, which enables smart metering utility networks (SUN) nodes to achieve energy saving and maximum service life.

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Lin, Chin-Feng, Tsung-Jen Su, Hung-Kai Chang, Chun-Kang Lee, Shun-Hsyung Chang, Ivan A. Parinov, and Sergey Shevtsov. "Direct-Mapping-Based MIMO-FBMC Underwater Acoustic Communication Architecture for Multimedia Signals." Applied Sciences 10, no. 1 (December 27, 2019): 233. http://dx.doi.org/10.3390/app10010233.

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In this paper, a direct-mapping (DM)-based multi-input multi-output (MIMO) filter bank multi-carrier (FBMC) underwater acoustic multimedia communication architecture (UAMCA) is proposed. The proposed DM-based MIMO-FBMC UAMCA is rare and non-obvious in the underwater multimedia communication research topic. The following are integrated into the proposed UAMCA: A 2 × 2 DM transmission mechanism, a (2000, 1000) low-density parity-check code encoder, a power assignment mechanism, an object-composition petrinet mechanism, adaptive binary phase shift keying modulation and 4-offset quadrature amplitude modulation methods. The multimedia signals include voice, image, and data. The DM transmission mechanism in different spatial hardware devices transmits different multimedia packets. The proposed underwater multimedia transmission power allocation algorithm (UMTPAA) is simple, fast, and easy to implement, and the threshold transmission bit error rates (BERs) and real-time requirements for voice, image, and data signals can be achieved using the proposed UMTPAA. The BERs of the multimedia signals, data symbol error rates of the data signals, power saving ratios of the voice, image and data signals, mean square errors of the voice signals, and peak signal-to-noise ratios of the image signals, for the proposed UAMCA with a perfect channel estimation, and channel estimation errors of 5%, 10%, and 20%, respectively, were explored and demonstrated. Simulation results demonstrate that the proposed 2 × 2 DM-based MIMO-FBMC UAMCA is suitable for low power and high speed underwater multimedia sensor networks.

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Sharma, Neeraj, Sunil Agrawal, Vinod Kapoor, and Sumit Budhiraja. "Effects of Laser Linewidth on the Performance of DP-QPSK DWDM System." Journal of Optical Communications, November 9, 2019. http://dx.doi.org/10.1515/joc-2019-0182.

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AbstractThis paper analyzes the effects of laser linewidth on the performance of eight-channel dual-polarization quadrature phase-shift keying (DP-QPSK) dense wavelength division multiplexing (DWDM) transmission at 50 GHz channel spacing. The performance of differential encoding and Gray coding is compared with the system without any coding for the DP-QPSK DWDM system. It is shown that the differentially-encoded system performs better for lasers with linewidth (∆ν) greater than 0.04 MHz compared to the system with Gray coding and system without any coding. However, for lasers with linewidth lesser than 0.04 MHz, the three systems considered here perform equally and there is no need for differential or Gray coding in such a case. It is also shown that if we apply frequency offset estimation (FOE) before adaptive equalization (AE) in the digital coherent receiver then it further improve the performance of the differentially encoded system with lasers sources having linewidth even greater than 0.1 MHz.

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Journal articles on the topic 'Shaped Offset Quadrature Phase Shift Keying'

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