90 research outputs found
Self-concatenated code design and its application in power-efficient cooperative communications
In this tutorial, we have focused on the design of binary self-concatenated coding schemes with the help of EXtrinsic Information Transfer (EXIT) charts and Union bound analysis. The design methodology of future iteratively decoded self-concatenated aided cooperative communication schemes is presented. In doing so, we will identify the most important milestones in the area of channel coding, concatenated coding schemes and cooperative communication systems till date and suggest future research directions
Turbo Decoding and Detection for Wireless Applications
A historical perspective of turbo coding and turbo transceivers inspired by the generic turbo principles is provided, as it evolved from Shannonâs visionary predictions. More specifically, we commence by discussing the turbo principles, which have been shown to be capable of performing close to Shannonâs capacity limit. We continue by reviewing the classic maximum a posteriori probability decoder. These discussions are followed by studying the effect of a range of system parameters in a systematic fashion, in order to gauge their performance ramifications. In the second part of this treatise, we focus our attention on the family of iterative receivers designed for wireless communication systems, which were partly inspired by the invention of turbo codes. More specifically, the family of iteratively detected joint coding and modulation schemes, turbo equalization, concatenated spacetime and channel coding arrangements, as well as multi-user detection and three-stage multimedia systems are highlighted
VLSI Architecture for Configurable and Low-Complexity Design of Hard-Decision Viterbi Decoding Algorithm
Convolutional encoding and data decoding are fundamental processes in convolutional error correction. One of the most popular error correction methods in decoding is the Viterbi algorithm. It is extensively implemented in many digital communication applications. Its VLSI design challenges are about area, speed, power, complexity and configurability. In this research, we specifically propose a VLSI architecture for a configurable and low-complexity design of a hard-decision Viterbi decoding algorithm. The configurable and low-complexity design is achieved by designing a generic VLSI architecture, optimizing each processing element (PE) at the logical operation level and designing a conditional adapter. The proposed design can be configured for any predefined number of trace-backs, only by changing the trace-back parameter value. Its computational process only needs NÂ +Â 2 clock cycles latency, with N is the number of trace-backs. Its configurability function has been proven for NÂ =Â 8, NÂ =Â 16, NÂ =Â 32 and NÂ =Â 64. Furthermore, the proposed design was synthesized and evaluated in Xilinx and Altera FPGA target boards for area consumption and speed performance
Further Specialization of Clustered VLIW Processors: A MAP Decoder for Software Defined Radio
Turbo codes are extensively used in current communications standards and have a promising outlook for future generations. The advantages of software defined radio, especially dynamic reconfiguration, make it very attractive in this multi-standard scenario. However, the complex and power consuming implementation of the maximum a posteriori (MAP) algorithm, employed by turbo decoders, sets hurdles to this goal. This work introduces an ASIP architecture for the MAP algorithm, based on a dual-clustered VLIW processor. It displays the good performance of application specific designs along with the versatility of processors, which makes it compliant with leading edge standards. The machine deals with multi-operand instructions in an innovative way, the fetching and assertion of data is serialized and the addressing is automatized and transparent for the programmer. The performance-area trade-off of the proposed architecture achieves a throughput of 8 cycles per symbol with very low power dissipation
Viterbi Accelerator for Embedded Processor Datapaths
We present a novel architecture for a lightweight Viterbi accelerator that can be tightly integrated inside an embedded processor. We investigate the acceleratorâs impact on processor performance by using the EEMBC Viterbi benchmark and the in-house Viterbi Branch Metric kernel. Our evaluation based on the EEMBC benchmark shows that an accelerated 65-nm 2.7-ns processor datapath is 20% larger but 90% more cycle efficient than a datapath lacking the Viterbi accelerator, leading to an 87% overall energy reduction and a data throughput of 3.52 Mbit/s
An Approach for Effective Design Space Exploration of Hard-Decision Viterbi Decoder: Algorithm and VLSI Implementation
Viterbi algorithmic rule is usually used as a cryptography technique for convolutional codes, bit detection technique, Trellis in storage devices. The design space for VLSI implementation of Viterbi decoders is massive, involving selections of turnout, latency, area and power. Even for a set of parameters like constraint length, encoder polynomials and trace-back depth, the task of de-signing a Viterbi decoder is kind of troublesome and needs important effort. Sometimes, as a result of incomplete style area exploration or incorrect analysis, a suboptimal style is chosen. This work analyzes the planning complexness by applying most of the identified VLSI implementation techniques for hard-decision Viterbi cryptography to a distinct set of code parameters. The conclusions square measure supported real styles that actual synthesis and layouts were obtained. In authorsâ read, as a result of the depth lined, it is the foremost comprehensive analysis of the subject revealed to this point
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