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A Decoder working on the logic of LDPC is designed for a 8 bit Logical ALU. The Simulation has been done to minimize the Voltage Leakage and Maximum throughput.
In this paper, we propose a new space-time block coding scheme to mitigate the effect of pilot contamination in multi-cell, massive Multiple-Input Multiple-Output (MIMO) systems. We derive the code design criterion and give some code design examples. Moreover, we present a new decoding method based on an oblique projection, which has a low decoding complexity. Simulation results show that our coding...
We consider an asynchronous two-way relay network, in which two double-antenna relays assist in the communication between two single-antenna terminals through analog network coding. The asynchronous transmission between relays and terminals causes symbol misalignments and results in diversity loss in space-time block code (STBC). We propose a zero-padded time-reversal quasi-orthogonal STBC that can...
In this paper, a fast sub-optimal decoding method is proposed for quasi-orthogonal space-time block codes (QOSTBCs) with four transmit antennas. The proposed method focuses on the phases of received vector to select an origin and create a limited region among proper candidates. The limited region and proper candidates are selected from some sorted lookup tables by utilizing the phases of received...
In this paper, decoding metrics are designed for statistical fingerprint-based content identification. A fairly general class of structured codes is considered, and a statistical model for the resulting fingerprints and their degraded versions (following miscellaneous content distortions) is proposed and validated. The Maximum-Likelihood fingerprint decoder derived from this model is shown to considerably...
We propose a half-duplex cooperative scheme for a discrete memoryless channel (DMC) consisting of two users communicating with one destination. The half-duplex constraint is satisfied by performing the communication over 3 time slots with variable durations in each code block. Each user alternatively transmits and receives during the first 2 time slots, then both of them transmit during the last one...
Imperfect channel estimation results in the introduction of symbols coupling for system with space time codes encoding when decoded by the mismatched filter. The bootstrap algorithm was suggested to be used as a signal separator at the output of the mismatched filter. In this work, this solution is studied in details for the Alamouti's code. An inherent problem of the bootstrap's weights control process...
Firstly, this paper gives a simple introduction of the encoding/decoding theory of LDPC and Space-time coding. And it carries out a detailed research and analysis on LDPC coding system and the space-time block coding system. Then, LDPC and space-time coding are combined. The performance of LDPC-STBC under AWGN channel is given through computer simulation. The simulation results show that this method...
Turbo codes play an important role in making communications systems more efficient and reliable. This paper provides a description of two turbo codes algorithms. Soft-output Viterbi algorithm and logarithmic-maximum a posteriori turbo decoding algorithms are the two candidates for decoding turbo codes. Soft-input soft-output (SISO) turbo decoder based on soft-output Viterbi algorithm (SOVA) and the...
In Brain Machine Interface (BMI), movement direction can be decoded using intra-cortical recordings such as Local Field Potentials (LFP). Due to the natural instability and non-stationarity of these recordings, it is difficult to develop decoders that remain consistent over time and are not affected by learning. This paper uses qualitative information based on the temporal and spatial distribution...
A modified sphere decoding (SD) scheme is proposed for multiple-input multiple-output (MIMO) communication systems in this paper. The conventional SD goes from the lower dimension to the higher dimension to examine whether a lattice point lies inside the sphere of some radius, which remains fixed for all dimensions. Since the sphere radius directly affects the search range and thus the complexity,...
Modern codes are often designed to attain the minimum possible error probability under a blocklength constraint. For instance, sparse-graph codes are often designed aiming for large girth in order to reduce the error-probability. In this paper, we show that such an improved performance comes at a fundamental cost: longer interconnects (wires) in the decoding circuit. Recent empirical results show...
This paper presents an efficient algorithm for the partial interference cancellation (PIC) group decoding. Partial interference cancellation is a linear operation that cancels interferences among symbol groups. The basic algorithm for the PIC operation requires a lot of matrix multiplications and inversions. Even though these matrix operations can be done in an efficient way by taking advantage of...
In this paper, the performance evaluation of an asymmetric turbo code for different codec parameters have been done. The asymmetric turbo codes performances are compared with symmetric counter part of the turbo code. With proper selection of weight configuration, the turbo code can show better results in both water fall region as well as error floor region simultaneously. So, in some cases asymmetric...
The convolution turbo code (CTC) has large memory power consumption. To reduce the power consumption of the state metrics cache (SMC), low-power memory-reduced trace back maximum a posteriori algorithm (MAP) decoding is proposed. Instead of storing all state metrics, the trace back MAP decoding reduces the size of the SMC by accessing difference metrics. The proposed trace back computation requires...
This paper considers random-coding bounds to the decoding error probability with maximum-metric mismatched decoders. Their error exponents are determined and the saddle-point approximation to the corresponding probability is derived. This approximation is accurate and allows for simple numerical evaluation, as verified for several channels of interest.
We consider a discrete memoryless channel between two users and a destination in half-duplex mode implemented by time division. Each transmission block of length n is divided into 3 time slots with variable durations. During the first two time slots, each user alternatively transmits and receives, while during the last time slot, they both transmit to the destination. Even though within each time...
After the initial interest caused by appearance of turbo-codes in 1993, special attention to the hardware implementation has led to many different modified algorithms for MAP decoders. The original MAP algorithm suffers from serious drawbacks in its hardware implementation. To overcome this disadvantage, Max-Log-MAP and Log-MAP algorithms have been proposed to reduce the complexity. Recently an improved...
We design a family of fast-decodable, rate-unbalanced space-time block codes (STBCs) for 4 × 2 multiple-input multiple-output (MIMO) transmission. These codes are generated by combining Alamouti and Silver codes into two layers. Their low-complexity decoder does MMSE successive interference cancellation (SIC) and sphere decoding. As shown by computer simulation, the proposed codes exhibit a better...
We propose a physical layer approach to detect the relay node that injects false data or adds channel errors into the network encoder in multiple access relay networks. The misbehaving relay is detected by using the maximum a posteriori (MAP) detection rule which is optimal in the sense of minimizing the probability of incorrect decision (false alarm and miss detection). The proposed scheme does not...
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