O. M. Collins and M. Hizlan, "Determinate state convolutional codes," IEEE Trans. Commun., vol. 41, pp. 1785--1794, Dec. 1993.  Home/Search   Document Not in Database   Summary   Related Articles   Check

....of the determinate bits increases. For example, when the determinate bit rate is 1 5, after five iterations, the error bit rate reduction is more than two orders of magnitude. Note that the improvement was obtained without modifying the two MAP decoders while in determinate convolutional codes [2], the convolutional decoding procedure takes into account the determinate states. It is expected that if the two MAP decoders are also modified, as is done in [2] to incorporate the knowledge of some bits in the bitstream, more improvement in error correction can be achieved. 2) Modification of ....

....of magnitude. Note that the improvement was obtained without modifying the two MAP decoders while in determinate convolutional codes [2] the convolutional decoding procedure takes into account the determinate states. It is expected that if the two MAP decoders are also modified, as is done in [2], to incorporate the knowledge of some bits in the bitstream, more improvement in error correction can be achieved. 2) Modification of Extrinsic Information Error Detected Source Information Feedback (EDSIF) A variation of the modification of Turbo decoding is designed to use different a ....

O. M. Collins and M. Hizlan, "Determinate state convolutional codes," IEEE Trans. Commun., vol. 41, pp. 1785--1794, Dec. 1993.

....In [11,19] a soft output Viterbi decoder is presented which provides reliability information to an outer RS decoder. The same structure could be applied to the concatenated scheme presented in this chapter. The soft decisions would further improve the performance. 5.3. 4 Variable rate RS codes [6, 10] describe another way of a concatenating RS and convolutional codes. This technique is also applicable to the cascade of Turbo RS code. With the help of iterative decoding between the two codes one can perhaps move the slope closer to 42 capacity. A Turbo Code block is again a multiple of a ....

O. M. Collins and M. Hizlan, "Determinate State Convolutional Codes," IEEE Transactions on Communications, vol. 41, pp. 1785--1794, Dec. 1993.

....compressed images. At the receiver, there is feedback from the postprocessing unit to the channel decoder, and decoding proceeds iteratively. During the first iteration, the decoder uses standard Viterbi decoding. The second and third iterations are based on the pinned state Viterbi algorithm [3]. For the fourth iteration, a listbased trellis decoder accepts feedback from the postprocessor and reconsiders the possible channel error locations until the post processor is satisfied with the decompressed image. In this paper, we remove the convolutional code and the feedback and substitute a ....

....algorithm [8] Then the image is decompressed and sent to the post processor. The post processor reduces the quantization noise and can also be used as a stopping criterion for the iterative MAP decoder, thereby reducing the average number of decoding iterations. Collins and Hizlan [3] have described a way of iteratively concatenating RS and convolutional codes. This technique is also applicable to the concatenation of RS and Turbo codes. With the help of iterative decoding between the two codes, we can obtain better performance with the same number of Turbo decoding iterations ....

O. Collins and M. Hizlan, "Determinate state convolutional codes", IEEE Trans. on Comm., vol. COM41, pp. 1785--1794, Dec. 1993.

....the concatenated coded systems for deep space communications. In the decoding process of a concatenated code, if the inner Viterbi decoder knows some information bits to be zero or one, we can improve the overall decoding performance by utilizing this information. For example, Collins and Hizlan[2] showed the decoding performance of determinate state convolutional code , which is superior to that of conventional one. One of the most important applications of such kinds of decoding is an iterative decoding for a generalizedconcatenatedconvolutional code (GCCC) The GCCC is a generalization ....

....information bit x i if c i = 1, which is called a known bit. Similarly, the bit x j corresponding to c j =0is called an unknown bit. Due to the information on the known bits, the Viterbi decoder needs to searches the maximum likelihood path only in a subset of all the codewords. As discussed in [2], the BER obtained from the decoding is smaller than that from the conventional Viterbi algorithm. The known bit flag c ff is determined in the following way: An interleaver INT I (1) of length L is a mapping from F L to itself, where F L is the set of all the binary L tuple. The ....

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O. M. Collins and M. Hizlan: "Determinate state convolutional codes", IEEE Trans. Comm., COM-41, pp. 1785-- 1794 (1993).

....decoder, the codeword segments that are practically known to be error free can be fed back to the convolutional decoder and used to pin certain trellis states for a second round of improved decoding. By using this approach, substantial coding gains have been reported by Lee [17] Collins [18], and Hagenauer et al. 19] Our application of pinning , which we call earlydetection , is meant to decrease decoding complexity, but not improve BER performance or improve coding gain. For example, turbocodes do not have component decoders with large minimum distance, so there is no way to ....

O. M. Collins, "Determinate state convolutional codes," IEEE Transactions on Communications, vol. 41, no. 12, pp. 1785--1794, December 1993.

....of the RTS performance. A further improvement could be made by taking advantage of the correct decoding of each RS codeword. The corrected symbols would be then used in a determinate state convolutional decoder which forces particular state transitions in a conventional convolutional decoder [76]. However, this path decision forcing algorithm is not currently available in commercial Viterbi decoders. 7.5 Conclusions The RTS algorithm is a simple method to lower the E b N 0 needed to achieve the desired BER for a standard concatenated scheme. For the particular case presented in this ....

O. M. Collins, "Determinate state convolutional codes," IEEE Transactions on Information Theory, vol. IT--41, pp. 1785--1794, Dec. 1993.

....standard determines the value of many bits in the header and allows detection of incorrect header information. The known bits reduce the number of paths through the trellis and decrease the probability of decoding an incorrect path. This is very similar to the pinned state decoder described in [5]. The third iteration considers the header to be known correctly and redecodes sections of the trellis corresponding to entropy coded image data which have been signaled by the post processor as possible sites for error events. The Source Image Output Image PostProcessing Source Coder Source ....

O. Collins and M. Hizlan, "Determinate State Convolutional Codes," IEEE Trans. on Communications, vol. 41, pp. 1785-1794, Dec. 1993.

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