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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It is clear that the conventional T- algorithm is not suitable for high-speed applications. To overcome this drawback, T-Algorithm has proposed in two variations, the relaxed adaptive VD [7], 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][8]. References Publications referenced by this paper.

In addition, the computational overhead is a small. On the other hand, the VD with conventional T- algorithm cannot achieve half of the clock speed of the full trellis VD.

Convolutional encoding with viterbi decoding is a good forward error correction suitable fod channels affected by noise degradation. Showing of ddecoder extracted citations. Through optimization at algorithm level greatly shortens the long critical path introduced by the T-algorithm.

Breadth-first trellis decoding with adaptive effort Stanley J. In most cases, one or two-step precomputation is a good choice. Trellis coded modulation schemes are used in many bandwidth efficient systems.

A fast ACSU architecture for Viterbi decoder using T-algorithm – Semantic Scholar

Abstract The viterbi decoder which is low power with convolution encoder is show in this paper. The synthesis targets to achieve the maximum clock speed for usibg case and the results are shown in Table III. Showing of 6 references. How to cite item. Viterbi Convolutional Encoding and Viterbi Decoding. Now, we further analyze the precomputation algorithm.


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Implementing the 4-to-2 priority encoder is much simpler than implementing the to-6 priority encoder. Skip to search form Skip to main content.

In [9], through a design example that, q -step pre- computation t-alforithm be pipelined into q stages, where the logic arcchitecture of each stage is continuously reduced as q increases.

Also, we assume that each remaining metric would cause a computational overhead of one addition operation. In some cases, the number of remaining metrics may slightly expand during a certain pipeline stage after addition with Bs.

Also, architectre kinds of low-power scheme would introduce extra hardware like the purge unit shown in Fig. For clarity, we only provide the main conclusion here. This process is straightforward, although the mathematical details are tedious.

General solutions for low power viterbi decoder design will be studied in our implementation work. Hamming distance and Euclidean distance [10].

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RE scheme with survival length of 42 is used for SMU and the register arrays associated with the purged states are clock-gated to reduce the power consumption in SMU. Ganesh KumarA. Usually, the extra delay can be absorbed by an optimized architecture or t-alogrithm design.

Low power Viterbi decoder for Trellis coded

The soft inputs of all VDs are quantized with 7 bits. This algorithm is suitable for TCM systems which always employ high-rate convolutional codes. At the receiver, a soft input VD should be employed to guarantee a good coding gain.


Therefore, the hardware overhead of the proposed VD is expected. Computational overhead compared with conventional T-algorithm is an important factor that should be carefully evaluated.

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

uisng Article Tools Print this article. Implementation of such a table is not trivial. In the 1-step pre-computation architecture, we have archirecture out that for the particular code shown in Fig.

However, for TCM systems, where high-rate convolutional codes are always employed, Two steps of precomputation could achieve the iteration bound or make a big difference in terms of clock speed.

There are two different types of SMU in the literature: The output of the priority encoder would be the unpurged state with the lowest index. Since the performance is the same as that of the conventional T-algorithm. Furthermore, the even states all extend to states with higher indices the MSB in Fig.

We again need to analyze the trellis transition of the original code. Where q is any positive integer that is less than n. Its truth table is shown in Table II and the corresponding logics are shown in 10 and However, searching for the optimal path metric in the feedback loop still reduces the decoding speed.

Hence Popt n can be calculated directly from Ps n-q in q cycles.