In this paper, we propose an efficient architecture based on pre-computation for Viterbi decoders incorporating T-algorithm. Through optimization at both. A Fast ACSU Architecture for Viterbi Decoder Using T-Algorithm. Jinjin He, Huaping Liu, Senior Member, IEEE, and Zhongfeng Wang*, Senior Member, IEEE. High performance ACS for Viterbi decoder using pipeline T-Algorithm .. Z. Wang, A fast ACSU architecture for Viterbi decoder using T-Algorithm, in: Proc.
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Power reduction in VDs could be achieved by reducing the number of states, for example reduced state sequence decoding , M- algorithm  and T-algorithm ,, or by over scaling the.
This process is straightforward, although the mathematical details are tedious. The architecture of TGU is shown in fig. Design of high speed low power viterbi decoder for TCM system J. Abdul SubhanDikpal Reddy Viterbi Convolutional Encoding and Viterbi Decoding.
Even if the extra delay is hard to eliminate, the resultant clock speed is very close to the theoretical bound. Therefore, a small number of precomputational steps is preferred even though the iteration bound may not be fully satisfied.
Firstbranch metrics are calculated in the B unit BMU from the received symbols.
It is well known that viterbi decoder is dominant module for finding the overall power consumption for the TCM decoders. The key point of improving the clock speed of T-Algorithm is to quickly find the optimal path metric. Implementation of Architectude coder for text to speech synthesis M. In order to reduce the computational complexity as well as power consumption, low power schemes should be exploited for the VD in a TCM decoder.
It is the same value as we obtained from direct architecture design . To decoser this drawback, T-Algorithm has proposed in two variations, the relaxed adaptive VD , Which suggests using an estimated optimal path metric, instead of finding the real one each cycle and the limited-search parallel state VD based on scarce state transition [SST].
Through optimization at algorithm level greatly shortens the long critical path introduced by the T-algorithm. Topics Discussed in This Paper.
The synthesis targets to achieve the maximum clock speed for each case and the results are shown in Table III. Very Large Scale Integr. Where q is any positive integer that is less than n.
A fast ACSU architecture for Viterbi decoder using T-algorithm
Skip to search form Skip to main content. In other words, If there are m remaining metrics after comparison in a stage, the computational overhead from this stage is at least m addition operations. Computational overhead compared with conventional T-algorithm is an important factor that should be carefully evaluated.
X 1 0 ………………………. Hence Popt n can be calculated directly from Ps n-q in q cycles. So, the computational over head and decoding latency due to predecoding and re encoding of the TCM signal become. For VD in-corporated with T- algorithm, no state is guaranteed to be cor at all clock cycles. Article Tools Print this article. The BMs are categorized in the same way and are described by 8.
The Branch metric can be calculated by two types: Theoretically, when t-algorlthm continuously decompose Ps n-1Ps n-2 ,……, the precomputation scheme can be extended to Q steps. In other words, the states can be grouped into m clusters, where all the clusters have the same number of states and all the states in the same cluster will be extended by the same Bs. It is essential to use T-algorithm t-agorithm Viterbi decoders to prune significant portions of the trellis states to dramatically reduce power consumption.
Each PM in all VDs is quantized viterbk 12 bits. The 64 states and path metrics are labeled from 0 to It is worth to mention that the conventional T -algorithm VD takes slightly more hardware than the proposed architecture, which is counterintuitive.
Low power Viterbi decoder for Trellis coded Modulation using T-algorithm
A total of received symbols 12 bits are simulated.
The minimum P becomes:. Javeed is pursuing his master of technology in VLSI systems in Bomma institute of technology and scienceJawaharlal Nehru technological university, India. This information allows us to obtain the 2-step pre-computation data path.
Email this article Login required. This architecture has been optimized to meet the iteration bound . Showing of 6 references.
A fast ACSU architecture for Viterbi decoder using T-algorithm – Semantic Scholar
Breadth-first trellis decoding with adaptive effort Stanley J. The Ps ardhitecture the current iteration are stored in the path metric unit PMU.
Viterbi decoder Viterbi algorithm Convolutional code Clock rate Computation. In , through a design example that, q -step pre- computation can be pipelined into q stages, where the logic delay of each stage is continuously reduced as q increases.
The results are shown in Table IV. The decrease of clock speed is inevitable since the iteration bound for VD with T -algorithm is inherently longer than that of avsu full-trellis VD.