This paper presents a novel scheme of high efficiency spreading spectrum modulation using double orthogonal complex sequences （DoCS）. In this scheme, input data bit-stream is split into many groups with length M. Ea...This paper presents a novel scheme of high efficiency spreading spectrum modulation using double orthogonal complex sequences （DoCS）. In this scheme, input data bit-stream is split into many groups with length M. Each group is then mapped into a word of width M and then utihzed to select one sequence from 2u-2 DoCS sequences each with length L. After that, the selected sequence is modulated on carrier in quadrature phase shift keying （QPSK） mode. In addition, a new method named forward phase correction （FPC） is put forward for carrier recovery. Theoretical analysis and bit-error-ratio（BER） experiment results indicate that the proposed scheme has better performance than the conventional direct sequence spread spectrum（DSSS） scheme both in bandwidth efficiency and processing gain of the receiver.展开更多
A decomposition of a graph H is a partition of the edge set of H into edge-disjoint subgraphs . If for all , then G is a decomposition of H by G. Two decompositions and of the complete bipartite graph are orthogonal i...A decomposition of a graph H is a partition of the edge set of H into edge-disjoint subgraphs . If for all , then G is a decomposition of H by G. Two decompositions and of the complete bipartite graph are orthogonal if, for all . A set of decompositions of is a set of k mutually orthogonal graph squares (MOGS) if and are orthogonal for all and . For any bipartite graph G with n edges, denotes the maximum number k in a largest possible set of MOGS of by G. Our objective in this paper is to compute where is a path of length d with d + 1 vertices (i.e. Every edge of this path is one-to-one corresponding to an isomorphic to a certain graph F).展开更多
基金Union Innovation Found of Jiangsu Province(No. BY2009149)
文摘This paper presents a novel scheme of high efficiency spreading spectrum modulation using double orthogonal complex sequences （DoCS）. In this scheme, input data bit-stream is split into many groups with length M. Each group is then mapped into a word of width M and then utihzed to select one sequence from 2u-2 DoCS sequences each with length L. After that, the selected sequence is modulated on carrier in quadrature phase shift keying （QPSK） mode. In addition, a new method named forward phase correction （FPC） is put forward for carrier recovery. Theoretical analysis and bit-error-ratio（BER） experiment results indicate that the proposed scheme has better performance than the conventional direct sequence spread spectrum（DSSS） scheme both in bandwidth efficiency and processing gain of the receiver.
文摘A decomposition of a graph H is a partition of the edge set of H into edge-disjoint subgraphs . If for all , then G is a decomposition of H by G. Two decompositions and of the complete bipartite graph are orthogonal if, for all . A set of decompositions of is a set of k mutually orthogonal graph squares (MOGS) if and are orthogonal for all and . For any bipartite graph G with n edges, denotes the maximum number k in a largest possible set of MOGS of by G. Our objective in this paper is to compute where is a path of length d with d + 1 vertices (i.e. Every edge of this path is one-to-one corresponding to an isomorphic to a certain graph F).
