In this paper, we present the performance of a parallel interference cancellation (PIC) scheme in Code division multiple access with cyclic prefix (CP-CDMA) systems and proposed a new model for cyclic prefix code division multiple access with less complexity and good resistance to near-far effect. This method is mostly used for broadband wireless communication in the uplink. Parallel interferen...

Abstract: In this paper, we mainly study the theory of linear codes over the ring R = Z4 + uZ4 + vZ4 + uvZ4. By the Chinese Remainder Theorem, we have R is isomorphic to the direct sum of four rings Z4. We define a Gray map Φ from R n to Z 4 , which is a distance preserving map. The Gray image of a cyclic code over R is a linear code over Z4. Furthermore, we study the MacWilliams identities of ...

In the theory of cyclic codes, it is common practice to require that (n,q)= 1, where n is the word length and Fq is the alphabet. This ensures that the generator g ( x ) of the cyclic code has no multiple zeros ( = repeated mots). Furthermore it makes it possible to use an idempotent element as generator. However, much of the theory also goes through without the restriction on n and q. Recently...

A general decoding method for cyclic codes is presented which gives promise of substantially reducing the complexity of decoders at the cost of a modest increase in decoding time (or delay). Significant reductions in decoder complexity for binary cyclic finite-geometry codes are demonstrated, and two decoding options for the Golay code are presented.

In this paper we show that the graph of k-ary trees, connected by rotations, contains a Hamilton cycle. Our proof is constructive and thus provides a cyclic Gray code for k-ary trees. Furthermore, we identify a basic building block of this graph as the 1-skeleton of the polytopal complex dual to the lower faces of a certain cyclic polytope.

Six new quasi-cyclic codes are presented, which improve the lower bounds on the minimum distance for a binary code. A local exhaustive search is used to find these codes and many other quasi-cyclic codes which attain the lower bounds.

In this paper we obtain a number of [70,35,12] singly even self-dual codes as a quasi-cyclic codes with m=2 (tailbitting convolutional codes). One of them is the first known code with parameters Beta=140 Gamma=0. All codes are not pure double circulant i.e. could not be represented in systematic form. Keywords—convolutional encoding, quasi-cyclic codes weight enumeratorg, double circulant

New mathematical techniques for analysis of raw dumps of NAND flash memory were developed. These techniques are aimed at detecting, by analysis of the raw NAND flash dump only, the use of LFSR-based scrambling and the use of a binary cyclic code for errorcorrection. If detected, parameter values for both LFSR and cyclic error-correcting code are determined simultaneously. These can subsequently...