Hans Dieterich

Generalized concatenation of convolutional codes

Generalized concatenation of inner and outer convolutional codes is studied. The essential problem is the partitioning of the inner code. A construction procedure to obtain a suitable equivalent description for a given code is derived, which gives the best possible distances in the partitioned subcodes. The construction rule is illustrated with two examples. A small code is studied to emphasize the ideas of the construction and a large code, namely the satellite standard code, demonstrates the considerable gains in decoding performance when using generalized concatenation. Furthermore, the possibilities for iterative decoding are pointed out.

Generalized concatenation of encoded tamed frequency modulation

A novel construction for encoded tamed frequency modulation (TFM) is introduced which is based on the principles of generalized concatenation. The inner TFM is partitioned into nested subsystems which increases the free Euclidean distances. In order to obtain a large distance among the nested TFM subsystems, the scrambler matrices have to be computed which transfer the original TFM into the equivalent TFM with better partitioning properties. Then outer convolutional codes with different error-correcting capabilities are used to protect the partitioning. The new concatenated and generalized concatenated constructions were simulated in an additive white Gaussian noise channel. A multistep decoding algorithm based on soft-output demodulation was used. We present various simulation results which show a significant coding gain in comparison with the best known trellis codes having the same trellis state complexity.

The construction and free distance estimation of generalized woven codes with outer warp

A new class of convolutional codes, namely generalized woven codes with outer warp is presented. The codes are based on nested classes of inner single convolutional code and many outer convolutional codes with different redundancies. We give a lower bound on the free distance for these codes.

Construction, analysis and performance of generalised woven codes

Generalised woven codes (WC) are constructed by combining the woven code structure with the idea of generalised concatenated codes, also known as multi-level codes. The required nested inner convolutional code is analysed. The encoder structure of this new class of codes is described and fundamental code parameters are derived. It is shown that generalised WC have a free distance which is superior to that of comparable WC. Several iterative and non-iterative decoding strategies are discussed. It is shown that the decoding complexity of the nested inner code is not larger than the decoding complexity of its mother code. Finally, bit error rates obtained from simulations are discussed and compared with other code structures like WC. Copyright

Generalized concatenated codes based on tamed frequency modulation

Using the principles of generalized concatenation we introduce a new design for encoded TFM. New constructions are based on inner nested (sub)systems of TFM signals and outer convolutional codes.