scholarly journals On the Error Performance of Coding and Equalization in Low-Complexity Ultra-Wideband Communication Systems

2017 ◽  
Vol 2 (3) ◽  
pp. 245
Author(s):  
Robert H. Morelos-Zaragoza

In this paper, the performance of various channel coding schemes is investigated in pulse-based ultra-wideband(UWB) communication systems for applications in short-range indoor environments. Pulse-based binary (BPSK) modulation and decision-feedback equalization (DFE) is considered. Concatenated adaptive equalization and coding is explored as an alternative to the more complex and often impractical joint coding and equalization. A block length of approximately 1000 bits is considered in this paper as it results in a static channel with minimal latency while still yielding relatively good error performance. The error performance of a previously proposed turbo product code (TPC), based on two identical Hamming (31,26) codes, is simulated and compared with that of otherchannel coding schemes of similar rate and code length. These include a regular LDPC (1057,813) code, a memory-6 rate-3/4 punctured convolutional code, a Reed-Solomon (127,89) code and a concatenated (off-the-shelf) code with a Reed-Solomon (255,239) outer code and a memory-6 rate-3/4 punctured convolutional inner code. The inclusion of the concatenated Reed-Solomon scheme serves as a reference, as this is an off-the-shelf classical and still popular solution. The simulation results show that, among the coding schemes considered, the LDPC code offers the best error performance.

2021 ◽  
Vol 4 (2) ◽  
pp. 1-8
Author(s):  
Shurooq M. Abdulkhudhur ◽  
Abdulkareem A. Kadhim

Huge data rates have been provided by 5G wireless communication systems using millimeter wave (mmWave) band that have frequencies ranging from 30 to 300 GHz.  mmWave provides much wider bandwidth than the existing 4G band.  The 5G network deals with massive number of devices.  This presents many challenges including capacity, end to end delay, data rate, and very large number of connections.  In this paper, the main task is to apply network coding to 5G mmWave communication system to increase the throughput of the communication links.  Simple packet-based network coding schemes using butterfly network topology are simulated.  The two network coding schemes considered here are Physical Layer Network Coding (PLNC) and Network Layer Network Coding (NLNC).   Models of Additive White Gaussian Noise (AWGN) and mmWave indoor fading channels are considered in the work using Quadrature Phase Shift Keying (QPSK) modulation. The results of the tests showed that the use of both NLNC and PLNC improved throughput in comparison to uncoded system.  Using PLNC increased the Bit Error Rate (BER) and the Packet Error Rate (PER), while NLNC scheme showed almost identical error performance to uncoded system over mmWave fading channel.  The results show that network coding improved throughput when compared.


2013 ◽  
Vol 11 ◽  
pp. 87-93 ◽  
Author(s):  
T. Arafa ◽  
W. Sauer-Greff ◽  
R. Urbansky

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.


2012 ◽  
Vol 15 (3) ◽  
pp. 17-26
Author(s):  
Nhan Chi Nguyen ◽  
Nghia Hoai Duong ◽  
Anh Van Dinh

Accurately modeling the channel is extremely important for the design of communication systems. Knowledge of the key features of the channel provides the designers with the ability to predict performance of the system for specific modulation, channel coding, and signal processing. In this paper, we will present the analysis of physical properties of the UWB channel model and propose an UWB channel model for short distance wireless communications (with a comparison to the IEEE 802.15.3a channel model). Through the analysis and design, conclusions related to the UWB channel model were drawn as follows: there are reflection, diffraction, multipath transmission, and signal attenuation with distance and frequency but there is no pulse distortion.


2018 ◽  
Vol 4 (2) ◽  
pp. 42-48
Author(s):  
Shamsuddeen Hassan Muhammad ◽  
Abdulrasheed Mustapha

Viterbi algorithm is a maximum likelihood decoding algorithm. It is used to decode convolutional code in several wireless communication systems, including Wi-Fi. The standard Viterbi algorithm gives just one decoded output, which may be correct or incorrect. Incorrect packets are normally discarded thereby necessitating retransmission and hence resulting in considerable energy loss and delay. Some real-time applications such as Voice over Internet Protocol (VoIP) telephony do not tolerate excessive delay. This makes the conventional Viterbi decoding strategy sub-optimal. In this regard, a modified approach, which involves a form of List Viterbi for decoding the convolutional code is investigated. The technique employed combines the bit-error correction capabilities of both the Viterbi algorithm and the Cyclic Redundancy Check (CRC) procedures. It first uses a form of ‘List Viterbi Algorithm’ (LVA), which generates a list of possible decoded output candidates after the trellis search. The CRC check is then used to determine the presence of correct outcome. Results of experiments conducted using simulation shows considerable improvement in bit-error performance when compared to classical approach.


Author(s):  
Salima Belhadj ◽  
Abdelmounaim Moulay Lakhdar ◽  
Ridha Ilyas Bendjillali

<p><span>Channel coding for the fifth generation (5G) mobile communication is currently facing new challenges as it needs to uphold diverse emerging applications and scenarios. Massive machine-type communication (mMTC) constitute one of the main usage scenarios in 5G systems, which promise to provide low data rate services to a large number of low power and low complexity devices. Research on efficient coding schemes for such use case is still ongoing and no decision has been made yet. Therefore, This paper compares the performance of different coding schemes, namely: tail-biting convolutional code (TBCC), low density parity check codes (LDPC), Turbo code and Polar codes, in order to select the appropriate channel coding technique for 5G-mMTC scenario. The considered codes are evaluated in terms of bit error rate (BER) and block error rate (BLER) for short information block lengths (K ≤ 256). We further investigate their Algorithmic complexity in terms of the number of basic operations. The Simulation results indicate that polar code with CRC-aided successive cancelation list decoder has better performance compared with other coding schemes for 5G-mMTC scenario.</span></p>


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