O. Joressen and H. Meyr. Terminating the trellis of turbo-codes. Electronics Letters, pages 1285--1286, 1994.  Home/Search   Document Not in Database   Summary   Related Articles   Check

....i.e. higher rates, and two differing component scramblers. Moreover, we will always assume that both component scramblers are terminated (i.e. in the zero state) after the input of u (1) and u (2) respectively. This can be accomplished in the Turbo encoder by the method described in [2]. Fig. 2: Example of a component scrambler with feed back polynomial 7 and feed forward polynomial 5 In order to explain our interleaver analysis method, we need to introduce the following term. An error pattern is a scrambler input sequence that at first drives the associated scrambler out of ....

O. Joressen and H. Meyr. Terminating the trellis of turbo-codes. Electronics Letters, pages 1285--1286, 1994.

....assumed in the remainder of the paper that the first encoder is forced to return to the all zero state and that the final state of the second encoder is unknown. Special interleaver structures that result in both encoders returning to the all zero state are discussed in [31] 32] 34] 35] and [36]. 2.1 Performance Bounds In order to make clear the distinction between Turbo codes and convolutional codes, it is useful to consider these codes as block codes. To this end, the input sequences are restricted to length N , where N corresponds to the size of the interleaver in the Turbo encoder. ....

O. Joerssen and H. Meyr, "Terminating the trellis of turbo-codes", Electronics Letters, Vol. 30, No. 16, pp. 1285--1286, August 4, 1994.

....in the remainder of the paper that the first encoder is forced to return to the all zero state and that the final state of the second encoder is unknown. Special interleaver structures that result in both encoders returning to the all zero state are discussed in [31] 32] 34] 35] and [36]. 2.1 Performance Bounds In order to make clear the distinction between Turbo codes and convolutional codes, it is useful to consider these codes as block codes. To this end, the input sequences are restricted to length N , where N corresponds to the size of the interleaver in the Turbo encoder. ....

O. Joerssen and H. Meyr, "Terminating the trellis of turbo-codes", Electronics Letters, Vol. 30, No. 16, pp. 1285--1286, August 4, 1994.

....that there is no simple solution to terminate both encoders at the same time in the same state using only # bits where # is the encoder memory size of the convolutional code. To achieve this, a complicated method based on inserting certain bits in pre determined positions was presented in [47]. We explain in this section a simple interleaver design for rate half turbo codes which allows both encoders of a turbo encoder to end in the same state [48] This method is more bandwidth efficient and will improve the performance of turbo codes when the MAP decoding algorithm is used. Until ....

O. Joerssen and H. Meyr, "Terminating the trellis of turbo--codes," Electron. Lett., vol. 30, No. 16, pp. 1285--1286, Aug. 1994.

....encoders begin and end in a known state. This can be obtained by constraining some input symbols, in some fixed positions of u, to be linearly dependent on the others. The number of termination symbols and their positions depend on the method used for termination and on the encoders memory (see [5], 6] and references therein) In the case of termination, turbo codes are binary linear systematic block codes. Otherwise they are cyclostationary convolutional codes, whose trellis is periodic of period k. However, they can still be decoded on a block by block basis, with a slight performance ....

O. Joersson, H. Meyr, "Terminating the trellis of turbo-codes," Electronic Letters, Vol. 30, No. 16, August 1994, pp. 1285-1286.

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