In this paper, a method of constructing a sequenceset similar to Walsh Hadamard (WH) codes is described. In general, two complementary sequence set of length 2 is used as a basic kernel to construct WH codes. In this...
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In this paper, a method of constructing a sequenceset similar to Walsh Hadamard (WH) codes is described. In general, two complementary sequence set of length 2 is used as a basic kernel to construct WH codes. In this work, four complementary sequence set of length 3 is used as a basic kernel. The proposed code set have a nearly non linear phase sequences with a more evenly spread frequency spectrum when compared with WH codes. It is shown that the proposed spreading codes perform comparable to WH in a Direct sequence code division multiple access (DS-CDMA) system in an Additive White Gaussian Noise and Rayleigh channel at a reduced code length. In this work, bit error rate performance of the Underlay Cognitive Radio system implemented using DS-CDMA system is simulated. Primary and Secondary Users are distinguished by assigning spreading codes from different families and it is assumed that the channel information is known by both the Primary and Secondary User receivers. This new code set offers good performance in a Cognitive Radio Underlay system.
Based on an interleaving technique and quadriphase periodic complementarysequence (CS) mates, this paper presents a method for constructing a family of 16-quadrature amplitude-modulation (QAM) periodic CS mates. The ...
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Based on an interleaving technique and quadriphase periodic complementarysequence (CS) mates, this paper presents a method for constructing a family of 16-quadrature amplitude-modulation (QAM) periodic CS mates. The resulting mates arise from the conversion of quadriphase periodic CS mates, and the period of the former is twice as long as that of the latter. In addition, based on the existing binary periodic CS mates, a table on the existence of the proposed 16-QAM periodic CS mates is given. Furthermore, the proposed method can also transform a mutually orthogonal (MO) quadriphase CS set into an MO 16-QAM CS set. Finally, three examples are given to demonstrate the validity of the proposed method.
In contemporary communications, Golay, periodic and Z-complementary sequence sets play a very important role, since such sequencesets possess impulse-like or zero correlation zone (ZCZ) autocorrelation. On the other ...
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In contemporary communications, Golay, periodic and Z-complementary sequence sets play a very important role, since such sequencesets possess impulse-like or zero correlation zone (ZCZ) autocorrelation. On the other hand, the advantages of the signals over the quadrature amplitude modulation (QAM) constellation are more and more prominent. Hence, the design of such sequencesets over the QAM constellation has turned into one of the all-important issues in communications. Therefore, the construction methods of such sequencesets over the 16-QAM constellation are investigated, in this letter, and our goals are arrived at by the known quaternary Golay, periodic and Z-complementary sequence sets. Finally, many examples illuminate the validity of the proposed methods,
A communication system with a combination of high order modulation and complementarysequences has lots of better properties, such as higher transmission data rates and spectrum efficiency, immunities to multiple acce...
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ISBN:
(纸本)9781467358293;9781467358309
A communication system with a combination of high order modulation and complementarysequences has lots of better properties, such as higher transmission data rates and spectrum efficiency, immunities to multiple access interference (MAI) and multi-path interference (MPI) synchronously, and so on. To satisfy the requirements of such a communication system, a construction method for yielding a family of 16-QAM periodic complementarysequence mates is presented in this paper. The proposed method transforms the known quaternary periodic complementarysequence (PCS) mates into the required 16-QAM ones. Due to a large number of available quaternary PCS mates, the resultant 16-QAM PCS mates are fairly rich.
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