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A FAST ACSU ARCHITECTURE FOR VITERBI DECODER USING T-ALGORITHM PDF

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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Viterbi Convolutional Encoding and Viterbi Decoding.

Low power Viterbi decoder for Trellis coded

Therefore, a straight forward implementation of T- Algorithm will dramatically reduce architecrure decoding speed. Suppose that we have labeled the states from 0 to This architecture has been optimized to meet the iteration bound [9].

It is worth to mention that the conventional T -algorithm VD takes slightly more hardware than the proposed architecture, which is counterintuitive.

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Compared with the SEPC-T algorithm, however, the critical path of the 1-sept pre-computation scheme is still long[12]. Now, we further analyze the precomputation algorithm.

This is because the former decoder has a much longer critical path usig the synthesis tool took extra measures to improve the clock speed. This information allows us to obtain the 2-step pre-computation data path. The output of the priority encoder would dexoder the unpurged state with the lowest index. Later in the next section we will report ASIC implementation results that have not been obtained earlier.

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Viterbi decoder Viterbi algorithm Convolutional code Clock rate Computation.

Low power Viterbi decoder for Trellis coded Modulation using T-algorithm

Section III presents the precomputation architecture with T-algorithm. First, we expand Ps at the current time slot n Ps n as a function of Ps n-1 to form a look-ahead computation of the optimal P-Popt n.

Also, we assume that each remaining metric would cause a computational overhead of one addition operation. This paper has 27 citations. Com-pared with the conventional T-algorithm, the computational overhead of this architecture is 12 addition operations and a comparison, which is slightly more than the number obtained from the evaluation in 5.

Viterbi decoder Search for additional papers on this topic. X 1 0 ………………………. Therefore, it is worth to discuss the optimal number of precomputation steps. The functional block diagram of viterbi decoder with two step precomputation T-algorithm is shown in fig.

Abstract The viterbi decoder which is low power with convolution encoder is show in this paper. The minimum Architscture becomes:. Implementing the 4-to-2 priority encoder is much simpler than implementing the to-6 priority encoder. The synthesis targets to achieve the maximum clock speed for each case and the results are shown in Table III. Typically a TCM system employs a high rate convolutional code, which leads to high complexity of viterbi decoder for the TCM decoder, when the constraint length of Convolutional code is also normal.

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In most cases, one or two-step precomputation is a good choice.

When applied to high rate convolutional codes, the relaxed adaptive VD suffers a severe degradation of bit- error-rate BER performance due to the inherent drifting error between the estimated optimal path metric and the accurate one[9]. 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.

Basically M-Algorithm requires a sorting process in a feedback loop where as T— Algorithm only searches for the optimal path metric [P] that is the maximum value or the minimum value of Ps. Showing of 20 extracted citations.

If the target throughput is moderately high, virerbi proposed architecture can operate at a lower supply voltage, which will lead to quadratic power reduction compared to the conventional scheme. The trellis butterflies for a VD usually have a symmetric structure. Each PM in all VDs is quantized as 12 bits.