Efficient soft demodulation schemes for the DVB-S2X system

2015 ◽  
Vol 34 (6) ◽  
pp. 833-858 ◽  
Author(s):  
Meixiang Zhang ◽  
Sooyoung Kim
Keyword(s):  
Soft Demodulation

Research on Soft Demodulation of Telemetry Signal Based on the Orthogonal Complex Baseband Rotating MSD

2014 ◽  
Vol 532 ◽  
pp. 152-156
Author(s):  
Gang Fu ◽  
Dong Xu Zhu ◽  
Qian He ◽  
Ming Xin Kou
Keyword(s):  
Test Results ◽  
Soft Demodulation ◽  
Detection Technology ◽  
Symbol Detection ◽  
Signal Demodulation ◽  
And Performance ◽  
Demodulation Method

For PCM/FM telemetry signal demodulation, compared to traditional demodulation method, multiple Symbol Detection technology (Multi - Symbol Detection, MSD) is an effective method for a lower demodulation threshold.[ For software MSD demodulation in the process of PCM/FM telemetry signal algorithm is too complex and cause a large computation takes longer problem, research based on baseband complex rotating orthogonal MSD soft PCM/FM signal demodulation method, this algorithm can greatly reduce the amount of calculation of MSD and performance with the ordinary MSD are basically identical. The simulation and test results verify the effectiveness of the proposed method.

Research on Soft Demodulation of Telemetry Signal in Reentry Telemetry Environment

2014 ◽  
Vol 543-547 ◽  
pp. 2555-2558
Author(s):  
Gang Fu ◽  
Dong Xu Zhu ◽  
Wen Jian Geng
Keyword(s):  
Phase Characteristic ◽  
Telemetry System ◽  
Test Results ◽  
Signal Phase ◽  
Signal Noise ◽  
Soft Demodulation ◽  
Synchronization Algorithm ◽  
Signal Demodulation ◽  
Demodulation Method ◽  
Target Spacecraft

PCM/FM system is one of the most widely used in the missile and rocket telemetry system. For the problem that the breakthrough tradition demodulation method of demodulation threshold leaded by the telemetry signals low signal noise ratio (SNR) of target spacecraft reentry telemetry environment, a baseband complex rotating orthogonal MSD based soft PCM/FM signal demodulation method is studied combined with the PCM/FM signal phase characteristic. The corresponding synchronization algorithm is applied to ensure the smooth operation of the demodulation. The simulation and test results verify the soft demodulation algorithm can make reduce the demodulation threshold effectively.

The Application of DFT Technology in Soft Demodulation of π/4-DQPSK Signals

2014 ◽  
Vol 644-650 ◽  
pp. 4439-4442
Author(s):  
Yan Jun Wu ◽  
Gang Fu ◽  
Peng Yu
Keyword(s):  
Simple Structure ◽  
Signal To Noise Ratio ◽  
Software Radio ◽  
Stable Region ◽  
Sampling Point ◽  
Receiver Design ◽  
Phase Shift Keying ◽  
Soft Demodulation ◽  
Shift Keying ◽  
Demodulation Method

Presented to the π / 4 differential quaternary phase shift keying signal (π/4-DQPSK) using the discrete Fourier transform (DFT) for software demodulation algorithm in consideration of the actual received waveform into transition to π/4-DQPSK District and stable region, and only the waveform sampling point DFT transform the region stable recovery decision. simulation gives the demodulation method to achieve the same differential demodulation relatively simple structure, and the anti-noise in the signal to noise ratio greater than 3dB better performance than the differential demodulation performance, expected the algorithm is applied π/4-DQPSK software radio receiver design.

scholarly journals A Combinatorial Approach to Evaluation of Reliability of the Receiver Output for BPSK Modulation with Spatial Diversity

10.37236/1028 ◽  
2006 ◽  
Vol 13 (1) ◽  
Author(s):  
S. Bliudze ◽  
D. Krob
Keyword(s):  
Symmetric Functions ◽  
Natural Extension ◽  
Schur Functions ◽  
Digital Signal ◽  
Spatial Diversity ◽  
Phase Shift Keying ◽  
Soft Demodulation ◽  
Shift Keying ◽  
Binary Phase Shift Keying ◽  
Bpsk Modulation

In the context of soft demodulation of a digital signal modulated with Binary Phase Shift Keying (BPSK) technique and in presence of spatial diversity, we show how the theory of symmetric functions can be used to compute the probability that the log-likelihood of a recieved bit is less than a given threshold $\varepsilon$. We show how such computation can be reduced to computing the probability that $U-V < \varepsilon$ (denoted $P(U-V < \varepsilon)$) where $U$ and $V$ are two real random variables such that $U=\sum_{i=1}^N |u_i|^2$ and $V=\sum_{i=1}^N |v_i|^2$ where the $u_i$'s and $v_i$'s are independent centered complex Gaussian variables with variances ${\Bbb E}[\,|u_i|^2\,]=\chi_i$ and ${\Bbb E}[\,|v_i|^2\,]=\delta_i$. We give two expressions in terms of symmetric functions over the alphabets $\Delta=(\delta_1,\dots,\delta_N)$ and $X=(\chi_1,\dots,\chi_N)$ for the first $2N-1$ coefficients of the Taylor expansion of $P(U-V < \varepsilon)$ in terms of $\varepsilon$. The first one is a quotient of multi-Schur functions involving two alphabets derived from alphabets $\Delta$ and $X$, which allows us to give an efficient algorithm for the computation of these coefficients. The second expression involves a certain sum of pairs of Schur functions $s_\lambda(\Delta)$ and $s_\mu(X)$ where $\lambda$ and $\mu$ are complementary shapes inside a $N\times N$ rectangle. We show that such a sum has a natural combinatorial interpretation in terms of what we call square tabloids with ribbons and that there is a natural extension of the Knuth correspondence that associates a (0,1)-matrix to each square tabloid with ribbon. We then show that we can completely characterise the (0,1)-matrices that arise from square tabloids with ribbons under this correspondence.

Research on Soft Demodulation of Anamorphic PCM/FM Signal under the Condition of Low SNR

2014 ◽  
Vol 532 ◽  
pp. 147-151
Author(s):  
Gang Fu ◽  
Dong Xu Zhu ◽  
Ren Long Li ◽  
Li Ping Wang
Keyword(s):  
Bit Error Rate ◽  
Signal To Noise Ratio ◽  
Joint Detection ◽  
Test Results ◽  
Selective Fading ◽  
Frequency Selective Fading ◽  
Low Snr ◽  
Soft Demodulation ◽  
Symbol Detection ◽  
Demodulation Method

Reentry telemetry channel is a special channel in the process of remote sensing, black barrier and multipath effect will cause the PCM/FM telemetry signal-to-noise ratio and frequency selective fading , even break through the traditional demodulation method of demodulation threshold, led to the bit error rate is greatly increased when aircraft fly through the reentry telemetry channel. Aiming at the problem, a sliding length of 1 more Symbol Detection (Multi - Symbol Detection, MSD) demodulation algorithm is studied: the continuous observations of N element signal and local signal for joint Detection, but each time the MSD sentences a MSD earlier with N - 1 element coincidence. In theory, the algorithm can increase the channel gain about 3 db, the simulation and test results verified the effectiveness of the proposed algorithm.

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