High-rate coded modulation schemes for 16 kbps speech in wireless systems

Author(s):  
E.A. Gelblum ◽  
N. Seshadri
2008 ◽  
Vol 2008 ◽  
pp. 1-4
Author(s):  
Luca Barletta ◽  
Arnaldo Spalvieri

This work focuses on high-rate () moderate-length () low-density parity-check codes. High-rate codes allow to maintain good quality of the preliminary decisions that are used in carrier recovery, while a moderate code length allows to keep the latency low. The interleaver of the LDPC matrix that we consider is inspired to the DVB-S2 standard one. A novel approach for avoiding short cycles is analyzed. A modified BP decoding algorithm is applied in order to deal with longer cycles. Simulations and results for the AWGN channel are presented, both for BPSK signalling and for coded modulation based on the partition .


2015 ◽  
Vol 4 (3) ◽  
pp. 249-252 ◽  
Author(s):  
Weichen Xiang ◽  
Stephane Le Goff ◽  
Martin Johnston ◽  
Kanapathippillai Cumanan

2012 ◽  
Vol 198-199 ◽  
pp. 1408-1412
Author(s):  
Lin Bo Su ◽  
Jian Hua Chen ◽  
Ying Peng Hu

Continuous Phase Modulation (CPM) schemes belong to a class of constant-envelope digital modulation schemes, the constant-envelope nature of the CPM signals makes them robust for the nonlinear and fading channels, and very useful for the satellite and/or the mobile radio channels. Comparing to PSK modulation, CPM modulation can not only provide spectral economy, but also exhibit a “coding gain”. CPM can be decomposed into a Continuous Phase Encoder (CPE) followed by a Memoryless Modulator (MM), this allows many new coded modulation schemes of combination of convolutional encoder and CPM modulator to be possible, such as serially-concatenated CPM (SC-CPM), SC-CPM with Convolutional Codes over Rings, pragmatic CPM (P-CPM), Concatenation of convolutional endocder and extended CE(CCEC), etc. Some simulations show that these new CPM schemes can offer superior performance.


The objective in this paper is to analyze the structural complexity of the non-binary coded modulation schemes for transmission over the digital communication channels which are band-limited and subjected to Intersymbol Interference (ISI). The design of reduced complexity M-QAM Coded Modulation schemes are analyzed algebraically. The performance is demonstrated through simulation.


2012 ◽  
Vol 20 (4) ◽  
pp. 243-248
Author(s):  
Weichen Xiang ◽  
Stéphane Le Goff ◽  
Zhiguo Ding

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