scholarly journals Low complexity Turbo synchronization without initial carrier synchronization

2010 ◽  
Vol 8 ◽  
pp. 123-128 ◽  
Author(s):  
U. Wasenmüller ◽  
C. Gimmler ◽  
N. Wehn
Keyword(s):  
Turbo Codes ◽  
Channel Coding ◽  
Communication Systems ◽  
Low Complexity ◽  
Wireless Data ◽  
Carrier Synchronization ◽  
Wireless Data Transmission ◽  
Xilinx Fpga ◽  
Digital Communication Systems ◽  
Turbo Synchronization

Abstract. Wireless data transmission results in frequency and phase offsets of the signal in the receiver. In addition the received symbols are corrupted by noise. Therefore synchronization and channel coding are vital parts of each receiver in digital communication systems. By combining the phase and frequency synchronization with an advanced iterative channel decoder (inner loop) like turbo codes in an iterative way (outer loop), the communications performance can be increased. This principal is referred to as turbo synchronization. For turbo synchronization an initial estimate of phase and frequency offset is required. In this paper we study the case, where the initial carrier synchronization is omitted and an approach with trial frequencies is chosen. We present novel techniques to minimize the number of trial frequencies to be processed. The communications performance and effort of our method is demonstrated. Furthermore the implementation complexity of the whole system is shown on a Xilinx FPGA.

scholarly journals Analysis of iteration control for turbo decoders in turbo synchronization applications

2009 ◽  
Vol 7 ◽  
pp. 139-144
Author(s):  
T. Lehnigk-Emden ◽  
U. Wasenmüller ◽  
C. Gimmler ◽  
N. Wehn
Keyword(s):  
Turbo Codes ◽  
Channel Coding ◽  
Communication Systems ◽  
Wireless Data ◽  
Turbo Decoder ◽  
Wireless Data Transmission ◽  
Turbo Decoders ◽  
Xilinx Fpga ◽  
Digital Communication Systems ◽  
Turbo Synchronization

Abstract. Wireless data transmission results in frequency and phase offsets of the signal in the receiver. In addition, the received symbols are corrupted by noise. Therefore, synchronization and channel coding are vital parts of each receiver in digital communication systems. By combining the phase and frequency synchronization with an advanced iterative channel decoder (inner loop) e.g. turbo codes in an iterative way (outer loop), the communications performance can be further increased. This principle is referred to as turbo synchronization. The energy consumption and the peak throughput of the system depend on the number of iterations for both loops. An advanced iteration control can decrease the mean number of needed iterations by detecting correctly decoded blocks. This leads to a dramatic energy saving or to an increase of throughput. In this paper we present a new stopping criterion for decodable blocks for turbo decoding in interrelation with turbo synchronization. Furthermore the implementation complexity of the turbo decoder is shown on a Xilinx FPGA.

scholarly journals Performance analysis of highly improved hybrid turbo codes for 4G wireless networks

2019 ◽  
Vol 8 (4) ◽  
pp. 398
Author(s):  
M. Jose Raj ◽  
Dr. Sharmini Enoch
Keyword(s):  
Wireless Networks ◽  
Turbo Codes ◽  
Communication Systems ◽  
Turbo Code ◽  
Error Correcting Code ◽  
Low Complexity ◽  
Error Correcting Codes ◽  
4G Wireless ◽  
Low Complex ◽  
Digital Communication Systems

Efficient error correcting codes are essential in modern digital communication systems. Highly Improved Hybrid Turbo Code (HIHTC) is a low complex error and efficient error correcting code with excellentBit Error Rate (BER) which is comparable to Low Complexity Hybrid Turbo Codes (LCHTC), Improved Low Complexity Hybrid Turbo Codes (ILCHTC) and other Hybrid Turbo Codes. Rate 1/3 HIHTC shows a BER of 10-5 for E b/No of 1.7 dB which is closer to the E b/No of Improved Low Complexity Hybrid Turbo Codes. In this paper we analyze the performance of HIHTC in comparison with otherLow Complexity Hybrid Turbo Codes, for their performance in 4G and 5G wireless networks  

scholarly journals Introducing perforation when applying turbo codes

2021 ◽  
Vol 2094 (3) ◽  
pp. 032061
Author(s):  
A A Sidorenko
Keyword(s):  
Data Transmission ◽  
Turbo Codes ◽  
Communication Systems ◽  
Digital Communication ◽  
Turbo Code ◽  
Code Sequence ◽  
Transmission Channel ◽  
Comparison Results ◽  
Decoding Efficiency ◽  
Digital Communication Systems

Abstract The problem of adapting the degree of redundancy introduced in the process of error-correcting coding to the changing characteristics of the data transmission channel is urgent. Turbo codes, used in a variety of digital communication systems, are capable of correcting multiple errors occurring in the data transmission channel. The article compares the decoding efficiency for various options for introducing perforation into the code sequence generated by the turbo code encoder. Based on the comparison results, recommendations were made on the most appropriate option for the introduction of perforation.

scholarly journals Secure image transmission over wireless network

2018 ◽  
Vol 7 (4) ◽  
pp. 2758
Author(s):  
Salah A. Aliesawi ◽  
Dena S. Alani ◽  
Abdullah M. Awad
Keyword(s):  
Turbo Codes ◽  
Channel Coding ◽  
Communication Systems ◽  
Wireless Channels ◽  
Image Transmission ◽  
Signal Propagation ◽  
Data Encryption ◽  
Error Rates ◽  
Delay Spread ◽  
High Level

The advances recently seen in data compression, and communication systems, have made it viable to design wireless image transmission systems. For many applications such as confidential transmission, military and medical applications, data encryption techniques should be also used to protect the confidential data from intruders. For these applications, both encryption and compression need to be performed to transmit a message in a fast and secure way. Further, the wireless channels have fluctuating channel qualities and high bit error rates. In this paper, a new scheme based on encryption and channel coding has been proposed for secure image transmission over wireless channels. In the proposed scheme, the encryption process is based on keys generator and Chaotic Henon map. Turbo codes are utilized as channel coding to deal effectively with the channel errors, multipath signal propagation and delay spread. Simulation results show that the proposed system achieves a high level of robustness against wide different of attacks and channel impairments. Further, it improves image quality with acceptable data rates. 

scholarly journals Improving the performance of BICM-ID and MLC systems with different FEC codes

2013 ◽  
Vol 11 ◽  
pp. 87-93 ◽  
Author(s):  
T. Arafa ◽  
W. Sauer-Greff ◽  
R. Urbansky
Keyword(s):  
Turbo Codes ◽  
Channel Coding ◽  
Communication Systems ◽  
Forward Error Correction ◽  
Convolutional Codes ◽  
Coded Modulation ◽  
Modulation Formats ◽  
Coding Schemes ◽  
Multilevel Modulation ◽  
Exit Charts

Abstract. In bandwidth limited communication systems, the high data rate transmission with performance close to capacity limits is achieved by applying multilevel modulation schemes in association with powerful forward error correction (FEC) coding, i.e. coded modulation systems. The most important practical approaches to coded modulation systems are multilevel coding with multistage decoding (MLC/MSD) and bit interleaved coded modulation with iterative demapping and decoding (BICM-ID). Multilevel modulation formats such as M-QAM, which can be used as a part of coded modulation systems, have the capability of multilevel protection. Based on this fact, we investigate the methods to improve the performance of BICM-ID using multiple interleavers with different binary channel coding schemes such as convolutional codes, turbo codes and low-density parity-check (LDPC) codes. Moreover, an MLC system with parallel decoding on levels (PDL) at the receiver is considered. In our contribution, we propose to design the individual coding schemes using the extrinsic information transfer (EXIT) charts for individual bit levels in the constellation. Our simulation results show that the BICM-ID systems, taking into account different bit-level protections, can provide an improvement of 0.65 dB, 1.2 dB and 1.5 dB for 256-QAM with turbo, LDPC and convolutional codes, respectively. On the other hand, MLC systems with PDL designed using EXIT charts for individual bit levels can slightly improve the performance and eliminate the error floor compared to the systems with MSD.

scholarly journals Simulasi Sinkronisasi Carrier pada Modulasi Digital menggunakan Matlab

2014 ◽  
Vol 2 (2) ◽  
pp. 100
Author(s):  
DWI ARYANTA ◽  
ARSYAD RAMADHAN DARLIS ◽  
WIRDA SRI FARHANI
Keyword(s):  
Carrier Phase ◽  
Communication Systems ◽  
Digital Communication ◽  
Similar Data ◽  
Receiver Side ◽  
Carrier Synchronization ◽  
Phase Recovery ◽  
Recovery Method ◽  
Qam Modulation ◽  
Digital Communication Systems

ABSTRAKDalam sistem komunikasi digital, salah satu manfaat teknik pengkodean adalah sebagai efisiensi bandwidth. Pada kanal komunikasi, adanya noise akan mengganggu dan  menurunkan kinerja sistem komunikasi digital. Hal ini menyebabkan terjadinya kesalahan pendeteksian sinyal pembawa, yang mengakibatkan terjadi perubahan bit atau simbol pada sisi penerima. Untuk mengurangi kesalahan deteksi, maka dibutuhkan suatu mekanisme sinkronisasi carrier di sisi penerima untuk mendapatkan data yang serupa dengan data yang dikirim. Simulasi sinkronisasi carrier pada penelitian ini menggunakan metode carrier phase recovery pada modulasi digital M-PSK dan M-QAM dengan level modulasi 4 sampai dengan 32, menggunakan software Matlab versi 7.9. Hasil pengujian sistem yang telah dilakukan pada Eb/No dengan rentang 0 hingga 30 dB menunjukkan, adanya peningkatan kinerja sistem pada modulasi M-PSK dari 0,01352 sampai dengan 0,8546, dan pada modulasi M-QAM dari 0,0256  sampai dengan 0,7867.Kata Kunci: M-PSK, M-QAM, Kanal AWGN, BER, Eb/No, Phase RecoveryABSTRACTThe digital communication systems, one of the benefits coding techniques are as bandwidth efficiency. The communication channel, the presence of noise will disrupt and degrade the performance of digital communication systems. This leads to error detection of the carrier, resulting in a change of bits or symbols at the receiver side. To reduce the detection error, there is a need carrier synchronization at the receiver side to obtain similar data with the data sent. Simulation of carrier synchronization in this study using the carrier phase recovery method in digital modulation M-PSK and M-QAM modulation with levels 4 to 32, using Matlab software version 7.9. The results of system testing has been done on the Eb / No ranging from 0 to 30 dB shows, an increase in the performance of the system on the M-PSK modulation from 0.01352 to 0.8546, and the M-QAM modulation from 0.0256 to 0 , 7867. Keywords: M-PSK, M-QAM, AWGN Channel, BER, Eb/No, Phase Recovery

scholarly journals Low-Complexity Channel Codes for Reliable Molecular Communication via Diffusion

Sensors ◽  
2021 ◽  
Vol 22 (1) ◽  
pp. 41
Author(s):  
Sofia Figueiredo ◽  
Nuno Souto ◽  
Francisco Cercas
Keyword(s):  
Channel Coding ◽  
Communication Systems ◽  
Communication Channel ◽  
Low Complexity ◽  
Proof Of Concept ◽  
Test Bed ◽  
Experimental Proof ◽  
Channel Codes ◽  
Processing Power ◽  
Very High

It is envisioned that healthcare systems of the future will be revolutionized with the development and integration of body-centric networks into future generations of communication systems, giving rise to the so-called “Internet of Bio-nano things”. Molecular communications (MC) emerge as the most promising way of transmitting information for in-body communications. One of the biggest challenges is how to minimize the effects of environmental noise and reduce the inter-symbol interference (ISI) which in an MC via diffusion scenario can be very high. To address this problem, channel coding is one of the most promising techniques. In this paper, we study the effects of different channel codes integrated into MC systems. We provide a study of Tomlinson, Cercas, Hughes (TCH) codes as a new attractive approach for the MC environment due to the codeword properties which enable simplified detection. Simulation results show that TCH codes are more effective for these scenarios when compared to other existing alternatives, without introducing too much complexity or processing power into the system. Furthermore, an experimental proof-of-concept macroscale test bed is described, which uses pH as the information carrier, and which demonstrates that the proposed TCH codes can improve the reliability in this type of communication channel.

Vergleich von Hardware- und Software-Implementierungen in der digitalen Kommunikation am Beispiel der Kanalcodierung (Hardware-/Software Trade-Offs in Digital Communication Systems with Special Emphasis on Channel-Coding)

2003 ◽  
Vol 45 (6) ◽  
Author(s):  
Norbert Wehn
Keyword(s):  
Channel Coding ◽  
Communication Systems ◽  
Digital Communication ◽  
Trade Offs ◽  
Digital Communication Systems

ZusammenfassungUnsere heutige Informationsgesellschaft erfordert Datenzugriffe an jedem Ort und zu jeder Zeit. Bandbreite und Energie sind hierbei kritische Ressourcen. Deshalb benötigen drahtlose Kommunikationsstandards effiziente Fehlerkorrekturverfahren. In diesem Beitrag diskutieren wir den Entwurfsraum für fortgeschrittene Kanalcodierungsverfahren und präsentieren verschiedene Hardware- und Softwareimplementierungen.

scholarly journals Performance and Complexity Evaluation of Iterative Receiver for Coded MIMO-OFDM Systems

2016 ◽  
Vol 2016 ◽  
pp. 1-22 ◽  
Author(s):  
Rida El Chall ◽  
Fabienne Nouvel ◽  
Maryline Hélard ◽  
Ming Liu
Keyword(s):  
Channel Coding ◽  
Communication Systems ◽  
Forward Error Correction ◽  
Multiple Input Multiple Output ◽  
Low Complexity ◽  
Ofdm Systems ◽  
Mimo Detection ◽  
Iterative Receiver ◽  
Ldpc Decoder ◽  
Trade Offs

Multiple-input multiple-output (MIMO) technology in combination with channel coding technique is a promising solution for reliable high data rate transmission in future wireless communication systems. However, these technologies pose significant challenges for the design of an iterative receiver. In this paper, an efficient receiver combining soft-input soft-output (SISO) detection based on low-complexity K-Best (LC-K-Best) decoder with various forward error correction codes, namely, LTE turbo decoder and LDPC decoder, is investigated. We first investigate the convergence behaviors of the iterative MIMO receivers to determine the required inner and outer iterations. Consequently, the performance of LC-K-Best based receiver is evaluated in various LTE channel environments and compared with other MIMO detection schemes. Moreover, the computational complexity of the iterative receiver with different channel coding techniques is evaluated and compared with different modulation orders and coding rates. Simulation results show that LC-K-Best based receiver achieves satisfactory performance-complexity trade-offs.

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