scholarly journals A Soft-Output STBC Decoder for Aeronautical Telemetry

2020 ◽  
Vol 1 ◽  
pp. 13-20
Author(s):  
Yves Louet ◽  
Rami Othman ◽  
Alexandre Skrzypczak
Keyword(s):  
Fading Channels ◽  
Rayleigh Fading ◽  
Viterbi Algorithm ◽  
Pulse Amplitude ◽  
Signal Quality ◽  
Phase Shift Keying ◽  
Time Block ◽  
Trellis Coded ◽  
Quadrature Phase ◽  
Shift Keying

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

scholarly journals Research on single carrier frequency domain equalization system based on FQPSK modulation

2018 ◽  
Vol 17 ◽  
pp. 03012
Author(s):  
Meng Zhang ◽  
Zhisong Bie
Keyword(s):  
Frequency Domain ◽  
Carrier Frequency ◽  
Viterbi Algorithm ◽  
Cyclic Prefix ◽  
Phase Shift Keying ◽  
Frequency Domain Equalization ◽  
Single Carrier ◽  
High Power Amplifier ◽  
Quadrature Phase ◽  
Shift Keying

Feher-patented quadrature phase shift keying (fqpsk) modulation is proposed for single-carrier frequency domain equalization (sc-fde). this paper puts forward a new method modulation called cc-bcd-fqpsk. the fqpsk signal is oversampled to make that the discrete fourier transform (dft)/ inverse dft (idft) processing of it can be applied for sc-fde. the methodology for maintaining waveform continuity with a cyclic prefix (cp) is presented. wrap-around viterbi algorithm (wava) is suggested for demodulation after equalization at the receiver. simulation results show that sc-fde system based on cc-bcd-fqpsk modulation has higher spectral efficiency than linear modulation qpsk and is an effective approach for eliminating isi and using nonlinear high power amplifier.

scholarly journals Comparison of Bit Error Rate Performance of Various Digital Modulation Schemes over AWGN and Rayleigh Fading Channels using Simulink

2021 ◽  
Vol 9 (2) ◽  
pp. 7-16
Author(s):  
Md. Firoz Ahmed ◽  
Md. Faysal Ahmed ◽  
Abu Zafor Md. Touhidul Islam
Keyword(s):  
Fading Channels ◽  
Bit Error Rate ◽  
Rayleigh Fading ◽  
Rayleigh Fading Channels ◽  
Rate Performance ◽  
Phase Shift Keying ◽  
Digital Modulation ◽  
Modulation Techniques ◽  
Shift Keying ◽  
Modulation Schemes

Digital modulation increases information capacity, data security, and system availability while maintaining high communication quality. As a result, digital modulation techniques are in higher demand than analog modulation techniques due to their ability to transmit larger amounts of data. Amplitude Shift Keying (ASK), Frequency Shift Keying (FSK), Phase Shift Keying (PSK), Differential Phase Shift Keying (DPSK), and Quadrature Amplitude Modulation (QAM) are critical components of current communications systems development, particularly for broadband wireless communications. In this paper, the comparison of bit error rate performance of different modulation schemes (BPSK, QPSK, and16-QAM) and various equalization techniques such as constant modulus algorithm (CMA) and maximum likelihood sequence estimate (MLSE) for the AWGN and Rayleigh fading channels is analyzed using Simulink. BPSK outperforms QPSK and 16-QAM when compared to the other two digital modulation schemes. Among the three digital modulation schemes, BPSK is showing better performance as compared to QPSK and 16-QAM.

scholarly journals Multiple-Symbol Detection Scheme for IEEE 802.15.4c MPSK Receivers over Slow Rayleigh Fading Channels

2021 ◽  
Vol 2021 ◽  
pp. 1-19
Author(s):  
Gaoyuan Zhang ◽  
Haiqiong Li ◽  
Congzheng Han ◽  
Congyu Shi ◽  
Hong Wen ◽  
...  
Keyword(s):  
Fading Channels ◽  
Rayleigh Fading ◽  
Packet Error Rate ◽  
Phase Shift Keying ◽  
Observation Window ◽  
Detection Scheme ◽  
Second Best ◽  
Multiple Phase ◽  
Symbol Detection ◽  
Shift Keying

Although the full multiple-symbol detection (MSD) for IEEE 802.15.4c multiple phase shift keying (MPSK) receivers gives much better performance than the symbol-by-symbol detection (SBSD), its implementation complexity is extremely heavy. We propose a simple MSD scheme based on two implementation-friendly but powerful strategies. First, we find the best and second-best decisions in each symbol position with the standard SBSD procedure, and the global best decision is frozen. Second, for the remaining symbol positions, only the best and second-best symbol decisions, not all the candidates, are jointly searched by the standard MSD procedure. The simulation results indicate that the packet error rate (PER) performance of the simplified MSD scheme is almost the same as that of the full scheme. In particular, at PER of 1 × 10 − 3 , no more than 0.2 dB performance gap is observed if we just increase the observation window length N to 2. However, the number of decision metrics needed to be calculated is reduced from 256 to 2. Thus, much balance gain between implementation complexity and detection performance is achieved.

Packet Error Probability for Diversity Systems in Slow Rayleigh Fading and Gaussian Noise

1986 ◽  
Vol 23 (3) ◽  
pp. 239-244
Author(s):  
Matthew L. Luhanga
Keyword(s):  
Fading Channels ◽  
Gaussian Noise ◽  
Error Probability ◽  
Rayleigh Fading ◽  
Maximal Ratio Combining ◽  
Selection Combining ◽  
Phase Shift Keying ◽  
Differential Phase Shift ◽  
Differential Phase Shift Keying ◽  
Shift Keying

Analytical results on packet error probability for noncoherent frequency-shift-keying (NCFSK) and differential phase-shift-keying (DPSK) systems with diversity reception operating over slow Rayleigh fading channels with Gaussian noise are derived. Expressions obtained are applicable to two linear combining schemes: selection combining and maximal-ratio combining.

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