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A random access scheme for the collision channel without feedback is proposed. The scheme is based on erasure correcting codes for the recovery of packet segments that are lost in collisions, and on successive interference cancellation for resolving collisions. The proposed protocol achieves reliable communication in the asymptotic setting and attains capacities close to 1 [packets/slot]. A capacity...
In the digital communication systems, due to the random interference from the outside, digital code may be distorted during the transmission, so the receiver can't judge correctly, it makes the communication systems' BER increases greatly and affects the quality of communication. The target of this thesis is to design the encoding and decoding of Hamming code by VHDL language to elaborate how hamming...
Soft based linear block codes combined with linear modulation cannot obtain the coding gains by increasing iterations. In this paper, we propose rate-compatible turbo product codes with extended BCH codes by zero padding and shortening the row and/or column to adapt next generation (NG) DVB-RCS system. And also, in order to make various coding rates required on standard, we used different coding rates...
In this paper, we derive few new quasi-orthogonal space-time block codes for four transmit antennas. These codes differ from each other and existing codes in character matrices and/or correlated values in character matrices. These codes can be constructed using elementary sub-matrices. We also derive corresponding maximum-likelihood decoders for the proposed codes. We observe that decoding complexity...
In this work, network coding is employed to obtain maximum diversity order in a network where the users have independent information to transmit to a common base station. We elaborate on the recently proposed generalized dynamic network codes (GDNC), which can only achieve part of the maximum diversity order when the inter-user channels are subject to outages. In particular, by allowing the users...
Turbo product codes (TPC) are very suitable for applications requiring a large code length, a high code-rate, and good error performance. In the Chase decoding algorithm, normally a few least reliable positions are selected and the test sequences are generated from these positions. This paper proposes two methods to lower the complexity of the Chase-Pyndiah decoding algorithm. The first scheme reduces...
Channel coding has been studied for over 60 years while complex network has not been intensively investigated until recently. In this review paper, we aim to establish a linkage between channel coding and complex networks -- two seemingly unrelated topics. We show by two examples how the characteristics of complex networks can inspire new ways of designing channel codes. Finally, we give some future...
A sequential code such as an arithmetic code is a code that determines a prefix of the codeword from a prefix of the source sequence. The reciprocal of the time period in which the transmitter can send a single code symbol is called the transmission velocity. Since, at every moment, the restored length cannot be longer than the source length, the decoding rate is one at most. In this manuscript, we...
Design of a new Run Length Limited (RLL) code is presented. The new coding scheme has coding rate of R=2/5, with the minimum runlength between two successive transitions equal to 4. This RLL (4, ∞) code uses channel capacity extremely efficiently, 98.7% and consequently it achieves density rate of DR=2.0. It has better efficiency than many other currently used codes for high density optical recording,...
Non-full spreading space-time block code(NFS-STBC) means the time period of one block is less than the number of transmit antennas($s<n_t$). NFS-STBC, compared with the conventional full spreading STBC(FS-STBC), have higher transmission rate but usually lower diversity order. In this paper, by considering the combination of STBC with bit- interleaved coded QAM modulations(BICM) systems, we propose...
Turbo product codes (TPCs) have been studied since 1994. However, existing decoding algorithms for TPCs are generally based on the algorithm presented by Pyndiah [1], which adopts the idea of MAX-Log-MAP algorithm and neglects the channel side information (CSI). In this paper, we present and investigate the "M-Log-MAP" decoding algorithm that considers multiple codewords in calculating the...
Special cases of the belief propagation algorithm are commonly used to decode various linear error correcting codes. We show that the belief propagation algorithm can also be applied to the decoding problem for nonlinear error correcting codes by considering a modified set of update rules. We demonstrate the modified belief propagation algorithm by applying it to the well-known Nordstrom-Robinson...
It is usually assumed that for implementing the maximum a posteriori (MAP) decoding algorithm, saving all the state metrics is required. This memory requirement makes the MAP an impractical decoding algorithm especially for the non-binary block codes. In this paper, we present a modification of the MAP algorithm, in order to make it a more feasible algorithm. The computational complexity analysis...
Forward Error Correction (FEC) is also named as "Forward Error Correcting Code" or “Channel Coding” which is a method used to increase the reliability of data communication. It is in the whole transmission process that encoding methods are performed at the transmitting end while decoding at the receiving end. This paper will show you the principle of FECs at first, including how they work...
Motivated by live streaming applications using peer assistance, we study burst erasure correction codes with optimal decoding delay for parallel-link networks. We consider a new model for network error correction, where each source symbol is decoded at the sink on-the-fly with a strict decoding deadline. We distinguish two types of errors which have very different implications on the code design --...
Hsiao and extended Hamming parity-check matrices can be used to define systematic linear block codes for Single Error Correction-Double Error Detection (SEC-DED). Their fixed code word parity enables the construction of low density parity-check matrices and fast hardware implementations. Fixed code word parity is enabled by an all-one row in extended Hamming parity-check matrices or by the constraint...
A sender and receiver are connected by two links, which both pass through a burst erasure channel. The channel induces an erasure burst of length B onto both links, but the bursts are separated by d time units. Source packets arrive at the sender, and are encoded with a streaming code such that the receiver can decode with a delay T. If source packet s[t] arrives at the sender at time t, then the...
Global Navigation Satellite Systems (GNSS), presently a USD 20 billion industry, has steadily growing applications in all possible spheres with some new high precision applications like indoor navigation etc. are at the cutting edge of the technology, thus requiring sophisticated FECs. In lieu of these facts and more, in this paper we undertake thorough analysis and comparison of Advanced FEC (such...
The main concern in slow fading channels is that the coded symbols can not be sent over multiple fades of the channel, because when they are transmitted across all strong and weak subchannels of a multiple-input multiple-output (MIMO) channel, the weak subchannels play the major role in the degradation of the total performance of the channel. In this paper, we propose a 2-dimensional transmit beamforming...
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