m-Sequences have been used widely in many applications, but the corresponding computation of the correlation-detection is overwhelming N2 operations, where N is the length of the m-sequence, such that it is unpracti...m-Sequences have been used widely in many applications, but the corresponding computation of the correlation-detection is overwhelming N2 operations, where N is the length of the m-sequence, such that it is unpractical. In this paper, a transform from p-ary m-sequence matrices to generalized Hadamard matrices is developed; and then by the fast generalized Hadamard matrices transform, a fast p-ary m-sequence transform is developed. The results show that the computation can be dramatically reduced from N2 to Nlog pN operations, so the fast p-ary m-sequence transform could enable a rapid correlation-detection at the receiver.展开更多
For two odd integers m and s with 1≤s < m and gcd(m, s) = 1, let h satisfy h(2~s-1) ≡1(mod 2~m+ 1) and d =(h + 1)(2~m-1) + 1. The cross correlation function between a binary m-sequence of period 22~m-1 and its d-...For two odd integers m and s with 1≤s < m and gcd(m, s) = 1, let h satisfy h(2~s-1) ≡1(mod 2~m+ 1) and d =(h + 1)(2~m-1) + 1. The cross correlation function between a binary m-sequence of period 22~m-1 and its d-decimation sequence is proved to take four values, and the correlation distribution is completely determined. Let n be an even integer and k be an integer with 1≤k≤n/2. For an odd prime p and a p-ary m-sequence {s(t)} of period p^n-1, define u(t) =∑(p^k-1)/2 i=0 s(d_it), where d_i = ip^(n/2) + p^k-i and i = 0, 1,...,(p^k-1)/2. It is proved that the cross correlation function between {u(t)} and {s(t)} is three-valued or four-valued depending on whether k is equal to n/2 or not, and the distribution is also determined.展开更多
A sub-optimum m-sequence method for reducing PAR distribution inPTS-OFDM is proposed in the pa- per. In order to reduce thecalculation load introduced by optimum PTS method, m-sequence offinding the optimum side infor...A sub-optimum m-sequence method for reducing PAR distribution inPTS-OFDM is proposed in the pa- per. In order to reduce thecalculation load introduced by optimum PTS method, m-sequence offinding the optimum side information can be utilized, which will notbring very heavy burden to the OFDM system since the cal- culationcomplexity is determined mainly by the number of IDFT at the cost ofPAR distribution performance of OFDM system.展开更多
Multiple access interference (MAI) is the most serious interference in spectral phase encoding optical code division multiple access (SPE OCDMA) systems. This paper focuses on the behavior of MAI in SPE OCDMA systems ...Multiple access interference (MAI) is the most serious interference in spectral phase encoding optical code division multiple access (SPE OCDMA) systems. This paper focuses on the behavior of MAI in SPE OCDMA systems with pseudorandom coding. The statistical expectation of multi access interference (MAI) is derived and plotted. The results confirm that MAI can be suppressed effectively by pseudorandom coding with m sequences.展开更多
The sequences which consist of any segment of a chaos sequence are called asC-sequences. These sequences could be used as a kind of input signals to replace M-sequences in theprocess identification. This substitution ...The sequences which consist of any segment of a chaos sequence are called asC-sequences. These sequences could be used as a kind of input signals to replace M-sequences in theprocess identification. This substitution is theoretically proved to be feasible. InverseC-sequences are created in a way similar to inverse M-sequences to solve the problem thatC-sequences have non-ideal balance property, that is, the numbers of '0' and '1' are unequal.Besides its good pseudo-random property, the sequences have other advantages such as easy togenerate, varieties of the segment and adjustable cycle time.展开更多
In this article, a novel transmit-reference (TR) signaling scheme is proposed for ultra-wideband (UWB) system, where by invoking m-sequence codes the reference and data pulses can be transmitted side by side to in...In this article, a novel transmit-reference (TR) signaling scheme is proposed for ultra-wideband (UWB) system, where by invoking m-sequence codes the reference and data pulses can be transmitted side by side to increase the data rate. This structure enables demodulation with a simple and practical autocorrelation receiver despite existence of severe inter-pulse interference (IPI) To evaluate detection performance of the new designs, closed-form expression for bit error probability (BRP) is theoretically derived and simulation results confirm the analytical results. In addition, the proposed scheme can be extended to M-ary systems to further improve the data rate and power efficiency.展开更多
Functional magnetic resonance imaging(fMRI)is one of the leading brain mapping technologies for studying brain activity in response to mental stimuli.For neuroimaging studies utilizing this pioneering technology,there...Functional magnetic resonance imaging(fMRI)is one of the leading brain mapping technologies for studying brain activity in response to mental stimuli.For neuroimaging studies utilizing this pioneering technology,there is a great demand of high-quality experimental designs that help to collect informative data to make precise and valid inference about brain functions.This paper provides a survey on recent developments in experimental designs for fMRI studies.We briefly introduce some analytical and computational tools for obtaining good designs based on a specified design selection criterion.Research results about some commonly considered designs such as blocked designs,and m-sequences are also discussed.Moreover,we present a recently proposed new type of fMRI designs that can be constructed using a certain type of Hadamard matrices.Under certain assumptions,these designs can be shown to be statistically optimal.Some future research directions in design of fMRI experiments are also discussed.展开更多
The measurement of the far-field radiation pattern is an important factor in describing the character-istics of the antenna.The measurement process is time consuming and expensive.Therefore,this paper proposes a novel...The measurement of the far-field radiation pattern is an important factor in describing the character-istics of the antenna.The measurement process is time consuming and expensive.Therefore,this paper proposes a novel method to reduce the number of samples required for radiation pattern measurement by adopting com-pressed sensing theory.This method reconstructs the radiation pattern from data measured by a few sensors,and the positions of these sensors are generated via the m-sequence.Simulation results demonstrate that the proposed algorithm can effectively reconstruct the complete radiation pattern by using the 50%samples.展开更多
基金TheNationalScienceFoundationofChina (No .6 0 30 2 0 15 )andtheFoundamentalScienceFoun dationofSouthwestJiaotongUniversity (No .2 0 0 3B0 5 )
文摘m-Sequences have been used widely in many applications, but the corresponding computation of the correlation-detection is overwhelming N2 operations, where N is the length of the m-sequence, such that it is unpractical. In this paper, a transform from p-ary m-sequence matrices to generalized Hadamard matrices is developed; and then by the fast generalized Hadamard matrices transform, a fast p-ary m-sequence transform is developed. The results show that the computation can be dramatically reduced from N2 to Nlog pN operations, so the fast p-ary m-sequence transform could enable a rapid correlation-detection at the receiver.
基金supported by National Natural Science Foundation of China (Grant No. 61170257)
文摘For two odd integers m and s with 1≤s < m and gcd(m, s) = 1, let h satisfy h(2~s-1) ≡1(mod 2~m+ 1) and d =(h + 1)(2~m-1) + 1. The cross correlation function between a binary m-sequence of period 22~m-1 and its d-decimation sequence is proved to take four values, and the correlation distribution is completely determined. Let n be an even integer and k be an integer with 1≤k≤n/2. For an odd prime p and a p-ary m-sequence {s(t)} of period p^n-1, define u(t) =∑(p^k-1)/2 i=0 s(d_it), where d_i = ip^(n/2) + p^k-i and i = 0, 1,...,(p^k-1)/2. It is proved that the cross correlation function between {u(t)} and {s(t)} is three-valued or four-valued depending on whether k is equal to n/2 or not, and the distribution is also determined.
文摘A sub-optimum m-sequence method for reducing PAR distribution inPTS-OFDM is proposed in the pa- per. In order to reduce thecalculation load introduced by optimum PTS method, m-sequence offinding the optimum side information can be utilized, which will notbring very heavy burden to the OFDM system since the cal- culationcomplexity is determined mainly by the number of IDFT at the cost ofPAR distribution performance of OFDM system.
基金Fund of Science and Technology Develop-ment of Shanghai(No.0 0 JC14 0 5 4
文摘Multiple access interference (MAI) is the most serious interference in spectral phase encoding optical code division multiple access (SPE OCDMA) systems. This paper focuses on the behavior of MAI in SPE OCDMA systems with pseudorandom coding. The statistical expectation of multi access interference (MAI) is derived and plotted. The results confirm that MAI can be suppressed effectively by pseudorandom coding with m sequences.
基金This work was financially supported by the National Natural Science Foundation of China (No.70071047, No.10247005)the Postdoctoral Science Foundation of China (No.2002032129)
文摘The sequences which consist of any segment of a chaos sequence are called asC-sequences. These sequences could be used as a kind of input signals to replace M-sequences in theprocess identification. This substitution is theoretically proved to be feasible. InverseC-sequences are created in a way similar to inverse M-sequences to solve the problem thatC-sequences have non-ideal balance property, that is, the numbers of '0' and '1' are unequal.Besides its good pseudo-random property, the sequences have other advantages such as easy togenerate, varieties of the segment and adjustable cycle time.
基金supported by the National Natural Science Foundation of China (60572118)the Specialized Research Fund for the Doctoral Program of Higher Education (20070013018)Innovation Foundation of BUPT (200622)
文摘In this article, a novel transmit-reference (TR) signaling scheme is proposed for ultra-wideband (UWB) system, where by invoking m-sequence codes the reference and data pulses can be transmitted side by side to increase the data rate. This structure enables demodulation with a simple and practical autocorrelation receiver despite existence of severe inter-pulse interference (IPI) To evaluate detection performance of the new designs, closed-form expression for bit error probability (BRP) is theoretically derived and simulation results confirm the analytical results. In addition, the proposed scheme can be extended to M-ary systems to further improve the data rate and power efficiency.
文摘Functional magnetic resonance imaging(fMRI)is one of the leading brain mapping technologies for studying brain activity in response to mental stimuli.For neuroimaging studies utilizing this pioneering technology,there is a great demand of high-quality experimental designs that help to collect informative data to make precise and valid inference about brain functions.This paper provides a survey on recent developments in experimental designs for fMRI studies.We briefly introduce some analytical and computational tools for obtaining good designs based on a specified design selection criterion.Research results about some commonly considered designs such as blocked designs,and m-sequences are also discussed.Moreover,we present a recently proposed new type of fMRI designs that can be constructed using a certain type of Hadamard matrices.Under certain assumptions,these designs can be shown to be statistically optimal.Some future research directions in design of fMRI experiments are also discussed.
基金the National Natural Science Founda-tion of China(No.61571146)。
文摘The measurement of the far-field radiation pattern is an important factor in describing the character-istics of the antenna.The measurement process is time consuming and expensive.Therefore,this paper proposes a novel method to reduce the number of samples required for radiation pattern measurement by adopting com-pressed sensing theory.This method reconstructs the radiation pattern from data measured by a few sensors,and the positions of these sensors are generated via the m-sequence.Simulation results demonstrate that the proposed algorithm can effectively reconstruct the complete radiation pattern by using the 50%samples.