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This paper reports low bit-error-rate (BER) polar codes concatenated low density parity check (LDPC) codes for wireless communication systems. The LDPC code has been validated on the error correction capable to approaching the theoretical value. However, the BER performance of this code is still limited because of the effect of the error floor. Therefore, a concatenated coding scheme based on polar...
Sparse code multiple access (SCMA) is a nonorthogonal multiple access scheme based on a multi-dimensional codebook with sparse codewords. The sparsity property of SCMA allows the receiver to take advantage of low-complexity message passing algorithm (MPA) detector with maximum likelihood (ML)-like performance. The use of multiple antennas at the SCMA receiver will improve the detection performance...
Progressive edge-growth (PEG) algorithm was proven to be a simple and effective approach to design good LDPC codes. However, the low-density parity-check (LDPC) constructed by PEG algorithm is of a single code rate. In this paper, we propose a modified PEG algorithm to construct multiple-rate LDPC codes, which is referred to as the multiple-rate PEG (MR-PEG) algorithm. The obtained LDPC codes with...
New Raptor codes, based on low rate low-density parity-check (LDPC) codes, are proposed for short message length over various channels. The proposed Raptor codes are obtained by pre-coding the information bits by low rate LDPC codes and utilizing a low constant average degree distribution with high intermediate symbol recovery rate (ISRR). Simulation results demonstrate that the proposed Raptor codes...
In the paper, we will discuss the powerfull class of channel codes referred to as turbo codes. We commence with a brief discussion for MAP and log-MAP decoding algorithms. Then we work with proposed turbo decoding method, which is called as PL-log-MAP. Some numerical results and research experiments, such as simulation for bit error rate estimation and images transmission have been presented. It is...
This paper presents channel model and error correction coding for correlated insertion/deletion errors in high-density magnetic recording media. Simulation results show that the bit error rate can be lowered by the presented coding.
To estimate the degradation in transmission quality of communication system under pulse burst disturbance, we introduce statistical parameters of noise to the research, and establish a quantitative relationship between bit error rate (BER) and statistical parameters, such as amplitude probability distribution (APD) and pulse duration distribution (PDD). There has been a method to evaluate BER with...
In this letter, a new early termination method is proposed for Luby transform (LT) belief propagation (BP) decoder. The proposed method is decided whether BP decoder output converges to original data bits by observing only sign alterations of log-likelihood ratio (LLR) messages in BP decoder structure. Simulation results and complexity analyzes show that proposed method has low computational complexity...
In this paper, we compare the performance of the generalized belief propagation detector and the layered generalized belief propagation detector with a Log-MAP algorithm and max algorithm for the message passing on the factor graph. Which message-passing sequential of the LGBP detector is used to update the nodes sequentially instead of simultaneously in the factor graph. The simulation results show...
Braided convolutional codes (BCCs) are a class of spatially coupled turbo-like codes (SC-TCs) with excellent belief propagation (BP) thresholds. In this paper we analyze the performance of BCCs in the finite block-length regime. We derive the average weight enumerator function (WEF) and compute the union bound on the performance for the uncoupled BCC ensemble. Our results suggest that the union bound...
Bit error rate(BER) analysis of an L antenna equal gain combiner (EGC) in correlated composite fading channels and in independent and identically distributed (i.i.d) non-homogenous fading channels is evaluated in the presence of co-channel interference(CCI) and imperfect estimation of carrier phase. The nth moment of the combiner output signal to interference plus noise ratio(SINR) is derived individually...
In order to overcome the major implementation problem of long delay line requirement in the conventional transmitted reference (TR) signaling, transmitted reference pulse cluster (TRPC) structure was proposed and further developed for noncoherent ultra-wideband (UWB) systems. In this paper, weighted autocorrelation receiver (WAcR) is introduced for the TRPC system with hybrid binary phase shift keying...
This paper investigates the capabilities of Hierarchical Quadrature Amplitude Modulation (HQAM) to provide Unequal Error Protection (UEP) to H.264/AVC encoded video bitstream. The UEP is based on the asymmetrical error sensitivity of the coded bitstream and exploits data partitioning mode of H.264/AVC to provide protection to their sensitivity to channel errors. The more important bits called High...
Transform domain communication system (TDCS) is a potential candidate for cognitive radio (CR). It is immune to the interception and has the characteristics of high spectral utilization. Nevertheless, large peak-to-average power ratio (PAPR) of the time domain signal inherently makes TDCS particularly sensitive to nonlinear distortion caused by the high power amplifier (HPA). In this paper, we analyze...
This paper proposes a novel uncoded digital modulation scheme with high spectral and power efficiency, denominated 32P-3D. This scheme has a symbol constellation that consists of 32 points symmetrically distributed in a threedimensional space. The theoretical analysis and the simulations show a considerably high performance against the noise in comparison to 16-ary Quadrature Amplitude Modulation...
Free space optical communication (FSO) has a long history, which communicates directly through the atmosphere, in a line of sight transmission by a set of transmission and receiver at both ends. Nowadays FSO is used as a fast and easy way of implementing solution for broadband communication. But there are factors including weather and distance that have an adverse effect on the transmission quality...
Transform domain communication system (TDCS) has been proposed to support multiuser communications through spectrum bin nulling and frequency domain spreading for overlay cognitive radio networks. In TDCS systems, specific pseudorandom spreading sequences are assigned to different users for the purpose of multiple access. However, due to the non-zero cross-correlations between any pair of TDCS signals,...
The Free Space Optics (FSO) proves to be a very effective and efficient technology for wireless communication. This emerging field basically uses invisible beams of light such as ultraviolet, infrared, etc. in order to provide optical bandwidth connections providing a high data rate than other technologies. This work exclusively deals with the designing of FSO systems using the simulation software...
Researchers in the field of computer networking often relies on appropriate simulators to diagnose network and to analyze the impact of various parameters on the network performance. There now exists several simulators (in the areas of wireless ad-hoc network) that offer various features to measure network performance. One such simulator that recently gained high popularity among researchers in the...
In this paper an enhanced version of DCSK (Differential Chaos Shift Keying) and HE-DCSK (High Efficiency Differential Chaos Shift Keying) named Very High Efficiency Differential Chaos Shift Keying system-Walsh Hadamard (VHE-DCSK-WH) is proposed. In this new system, we use N Walsh Hadamard (WH) codes to multiplex N different data bits. A single chaotic code is also used to ensure data spreading. As...
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