110 results about "Zero correlation" patented technology

A method for uplink synchronization of a first transceiver and a second transceiver in a multi-user cellular communication system having communication resources divided into communication channels. The method includes the following steps. A first signature sequence is transmitted from the second transceiver to the first transceiver, where the signature sequence is selected from a first set of signature sequences. In the first transceiver, the received signal is correlated with at least one signature sequence from a second set of signature sequences to estimate the time of arrival of the signature sequence to synchronize transmission between the second transceiver and the first transceiver. In transmitting the first signature sequence from the second transceiver to the first transceiver, the first signature sequence constitutes at least part of a zero-correlation zone sequence.

A direct sequence spread spectrum system consisting of modulator and demodulator wherein the spreading sequence with zero correlation zone properties, and the despreading consists of multiplying the received signal with the same spreading sequence, followed by a low pass filter, decoder and deinterleaver. The bit rate of the spreading sequence for each user is normally much higher than the input encoded data bit rate, and therefore it spreads the system spectrum.

The embodiment of the invention discloses a method and a device for allocating Zadoff-Chu (ZC) root sequence indexes, which are used for solving the problem of difficulty in the allocation of the ZC root sequence indexes in each cell. The method comprises the followings steps of: acquiring parameters of cells to be allocated, wherein the parameters comprise cell leading format types (1, 2, 3 and 4), cell types and cell radius values, and the cell types comprise a high-speed cell type and a low-speed cell type; acquiring an Ncs value of a configuration zone of a ZC zero correlation zone according to the cell radius values; and allocating the ZC root sequence indexes of the cells to be allocated according to the cell leading format types, the cell types and the Ncs value until the number of the cells to be allocated is zero and/or all the available root sequence indexes are used completely. By the embodiment of the invention, the ZC root sequence indexes of the cells to be allocated are allocated according to the cell leading format types, the cell types and the Ncs value, so that the problem of difficulty in the allocation of the ZC root sequence indexes in each cell is solved.

Ternary spreading codes in which side lobes near a peak of auth-correlation and cross-correlation are zero for a duration equal to or less than (0.75N+1) chips for a N chip period code are generated. The ternary spreading codes of the present invention is generated by (a) generating ternary zero correlation duration preferred pair codes, in which the zero correlation duration of (0.75N+1) chips is retained, by expanding a N chip period of a code, N being a natural number; and (b) generating a plurality of ternary zero correlation duration code sets having zero correlation characteristic equal to or less than (0.75N+1) chips by shifting the generated ternary zero correlation duration preferred pair codes in chips.

The invention relates to a method for forming a two-dimensional optical orthogonal code with a zero correlation window, and the method comprises following steps of constructing a first sequence with the zero correlation window; constructing a second sequence; and mapping the first sequence and the second sequence to form the two-dimensional optical orthogonal code with the zero correlation window. The invention also relates to a device for realizing the method. The method and the device for forming the two-dimensional optical orthogonal code with the zero correlation window have following beneficial effects that the two-dimensional orthogonal code is completely orthogonal, i.e. the autocorrelation limit of the code is zero, cross-correlation limit of the code is also zero, and thus the multi-address interference and beat noise can be completely eliminated, the near-far effect of a two-dimensional optical code division multiple access (OCDMA) system also can be eliminated; therefore, the two-dimensional OCDMA system with large capacity can be realized, and the two-dimensional OCDMA system can be applied to an optical access network, an optical local area network, an optical code mark switching network, an optical fiber sensor network and the like.

The proposed invention relates to the interference-free Ultra-Wide Band (UWB) wireless communication system using spreading codes with low correlation duration or Zero Correlation Duration (ZCD) property, the communication processing technique of the system and the record media of the program through the computer.

The present invention discloses a method for generating a zero correlation zone code. The method comprises the following procedures: combining a linear feedback shift register sequence (m sequence) with initial maximum length with sequence (1) to basic code; and expanding the basic code to generate the zero correlation zone code. The invention additionally discloses a method for generating and transmitting the spectrum spreading code with the zero correlation zone code. The method comprises the following procedures: expanding the basic code generated with the initial m sequence and sequence (1) for generating the zero correlation zone code; and inserting a nonzero protecting interval in the zero correlation zone code, generating and transmitting the spectrum spreading code. The invention also discloses a method for generating and receiving the spectrum spreading code with the zero correlation zone code. The invention further respectively discloses a device for generating the zero correlation zone code, a device for transmitting the spectrum spreading code and a device for receiving the spectrum spreading code. The method of the invention can increase the number of the available code of the generated zero correlation zone code thereby increasing the number of the available code of the transmitting spectrum spreading code and receiving spectrum spreading code generated with the zero correlation zone code.

The invention discloses a confirming method of a synchronization sequence in a multipoint collaborative environment, comprising the following steps of: confirming the length L of a synchronization code sequence with the characteristics of a zero correlation window, a group number M and the length ZCZ of the zero correlation window, wherein the L, the M and the ZCZ satisfy the flowing relation: L=22*n+m+1, M=2*n+1, ZCZ=2*n+m+1, n is an integer not smaller than 0, and m is a positive integer; and periodically rearranging the synchronization code sequence in a time domain to acquire the synchronization sequence of the system. The invention also discloses a synchronizing method in the multipoint collaborative environment, comprising the following steps of: carrying out the delay-based autocorrelation synchronization of a received signal by a user terminal to confirm a signal segment bearing the synchronization sequence; and carrying out cross-correlation calculation of the signal segment bearing the synchronization sequence by utilizing the synchronization sequence stored in the user terminal, wherein an initial signal peak value confirmed by the cross-correlation calculation is the start position of the signal bearing the synchronization sequence. The invention also discloses a device of the method and improves the synchronization performance of UE (User Equipment) on the edge of a district.

The invention discloses a generating method of inter-orthogonal mutual-complemeting code and a multi-carrier DS-CDMA cellular mobile communication system which utilizes said method to spread the spectrum. The inter-orthogonal mutual-complementing code attained by original orthogonal mutual-complementing code and orthogonal matrix operation has ideal features of self-correlation and cross-correlation while the self-correlation function of each code and the cross-correlation function between any two codes of group both have the zero correlation window and the cross-correlation function is complete complementary. The invention reaches the application of inter-orthogonal mutual-complementing code in the multi-carrier DS-CDMA cellular mobile communication system, which can realize the non-multiple access disturbing and non-adjacent residential disturbing.

The invention discloses a method for generating an inter-group orthogonal complementary sequence set. In the method, the conventional complementary sequences are circularly shifted to obtain shift complementary sequences; and the shift complementary sequences are interleaved by using an orthogonal matrix to obtain the inter-group orthogonal complementary sequence set. The obtained complementary sequence set comprises a plurality of complementary sequence groups; the complementary sequences in each group have ideal autocorrelation and mutual correlation performance; and the complementary sequences between different groups are mutually orthogonal. Both the complementary sequence set and each complementary sequence group included in the complementary sequence set reach theoretical limits of sequence design; the problem of capacity constraint of a communication system based on the conventional complementary sequence set can be solved; and the method can be used for non-interference communication of a code division multiple access communication system, main synchronization and auxiliary synchronization of a mobile communication system, channel estimation of an MIMO (Multiple Input Multiple Output) system, construction of mutually orthogonal zero correlation zone sequence set and the like.

The invention discloses a signal generation method of a low-interference multispeed multi-cell quasi-synchronous code division multiple access (CDMA) communication system. The method comprises the steps: a spread spectrum sequence code group is an Hadamard matrix set with certain idealized characteristics formed by Bent functions and a Walsh-Hadamard orthogonal sequence set; a sequence set with the characteristic of a similar zero correlation zone (ZCZ) sequence is obtained by calculating with a pair of complementary sequence sets by utilizing the Hadamard matrix set; and a plurality groups of sequence sets with the similar ZCZ sequence characteristics are obtained by carrying out Cartesian convolution operation with the orthogonal sequence set by utilizing the similar ZCZ sequence set. When a system maximum synchronization error and a channel maximum multipath delay spread are in the stated range, the system interference can be reduced greatly. The parameters of the spread spectrum sequence code group and the system efficiency can be adjusted and flexibly selected according to the practical factors. Therefore, the requirements of power control and synchronization by the CDMA communication system are reduced, and the complexity of system realization is lowered.

The invention discloses a construction method of a mutual orthogonal zero correlation zone multiphase sequence set and belongs to the technical field of communication system signal design. Based on a traditional zero correlation zone sequence set as a core set, a perfect sequence of cyclic shift is used, and a zero correlation zone sequence set can be expanded into a new sequence set including a plurality of mutual orthogonal zero correlation zone sequence sub-sets. The sequence set can reach a theoretical boundary of sequence design, can provide a sequence with a good interference restraining characteristic for a high-capacity code division multiple access communication system, and simultaneously can be used as a synchronous training sequence and signal channel estimation reference signals and the like of a communication system of orthogonal frequency division multiplexing and the like.

The method for mitigating interference in Orthogonal Frequency Division Multiplexing (OFDM) communications systems uses comb-type pilot signals in a doubly selective channel where the pilot signals are calculated to have zero correlation sequences in order to maintain orthogonality where there is a high Doppler effect to mitigate intercarrier interference. The pilot signals may be precomputed, stored in a look-up table, and selected based upon total power constraints of the pilot signals. The steps of the method may be performed by a Finite Impulse Response (FIR) equalizer.

The invention provides a method for determining the length set of the zero correlation zone, which includes: determining the length of the root sequence; selecting a zero correlation zone length set, for any sub-district radius, the maximum number of the lead determined by one zero correlation zone length selected from the selected zero correlation zone length set is mostly adjacent to the maximum number of the lead determined by any one zero correlation zone length selected from the set of all integers, wherein the maximum number of the lead is determined by the length of the root sequence and the length of the selected zero correlation zone. The invention provides also an apparatus, base station and mobile communication system for determining the length set of the zero correlation zone. In the invention, the selected ZCZ length finite set should conform to a definite condition, thereby providing a technical scheme of selecting a comparatively good ZCZ length finite set, and decreasing the signaling spending.

The invention provides a method for determining a zero correlation zone (ZCZ) length set, which comprises the following steps: determining the length of a root sequence; and selecting a ZCZ length set which is characterized in that for any cell radius, the maximum leading quantity determined by one ZCZ length selected from the selected ZCZ length set is most approximate to the maximum leading quantity determined by any one ZCZ length selected from a set of all integers, wherein the maximum leading quantity is determined by the length of the root sequence and the selected ZCZ length. The invention also provides a device, a base station and a mobile communication system for determining the ZCZ length set. In the invention, the selected finite set of the ZCZ lengths needs to meet certain conditions, and a technical scheme for selecting a better finite set of the ZCZ lengths is provided, thereby reducing the cost of signaling.

The invention belongs to the technical field of communication systems, and particularly relates to a method and a device for generating aperiodic four-phase Z complementary sequence pair signals in acommunication system. The method comprises the following steps: inputting a group of aperiodic binary Z complementary sequence pairs (a, b) with the zero correlation zone width of Z into a serial-parallel converter; correspondingly outputting each sequence element subjected to serial-parallel conversion to a symbol converter; the symbol converter processes the input sequence elements and outputs the sequence elements to the multiplying circuit; the multiplying circuit generates three paths of output; the adder performs staggered superposition on the three paths of output data of each sequenceelement in the sequence a and the three paths of output data of each sequence element in the sequence b to generate each sequence element of the non-periodic four-phase Z complementary sequence pair;performing parallel-serial conversion on each sequence element of the non-periodic four-phase Z complementary sequence pair by adopting a parallel-serial converter so as to output the non-periodic four-phase Z complementary sequence pair; the method can be applied to signal processing, communication systems, large-scale integrated circuit testing and the like.

The invention discloses a method for generating a signal for an interference-free quasi-synchronous CDMA communication system. A spectrum spreading sequence encode block is a sequence with the zero correlation property generated by an optimal self-correlation sequence and a Hadamard matrix and is suitable for a quasi-synchronous CDMA communication system. When the maximum synchronous error of the system and the maximum multipath delay of the channel are extended within the regulated range, the interference-free transmission is realized. The parameter of the spectrum spreading sequence encode block and the efficiency of the system can be adjusted in real time according to practical factors and to select flexibly. The method lowers the requirement of the CDMA communication system on the power control and the synchronization, and reduces the complexity of realizing the system.

The invention discloses a method for estimating a Doppler spread factor of a MIMO-OFDM underwater acoustic communication system by using a zero correlation zone (ZCZ) sequence as a training sequence. The method comprises the following steps: inserting two segments of repeated ZCZ sequences in front of a data frame, carrying out delayed autocorrelation operation on received signals by a receiving end by adopting a plurality of parallel correlators, and estimating the Doppler spread factor according to the window length of the correlator having the maximum output result. Compared with the existing Doppler spread estimation algorithm, the method can significantly improve the Doppler spread estimation accuracy and has strong channel adaptability, when the signal to noise ratio is greater than -5dB, the estimation accuracy is always kept to be 10<-4> or below, and the requirements of underwater acoustic communication with a high data rate for the estimation accuracy of the Doppler spread factor are satisfied.

The invention discloses a continuous pilot processing method and a continuous pilot processing device for a digital wireless communication system. The method comprises the following steps of: determining the width of a pilot code block zero correlation window according to a minimum network topology structure and a target network topology structure of the digital wireless communication system; determining the length of a complete complementary orthogonal code pair according to the width of the pilot code block zero correlation window; comparing the number of pilots which can be provided by the digital wireless communication system with the number of the pilots to be transmitted, and determining a pilot periodical transmission structure according to a comparison result; and transmitting the pilots generated according to the complete complementary orthogonal code pair in the digital wireless communication system according to the determined periodical transmission structure. By the method and the system, the number of the pilots can be greatly reduced, system resource consumption is reduced, and interference among the pilots and between the pilots and service channels are completely eliminated.

The invention provides a zero correlation zone (ZCZ) sequence initial phase estimation method based on sliding window search. The method comprises the steps of determining a sliding range of a sliding window; determining a detecting threshold; finding the maximum amplitude values of sampling points in the current sliding window, moving the center position of the sliding window on the position of the maximum amplitude values; obtaining a checking threshold; judging whether only one peak exists in the sliding window and whether the peak is placed near the center of the sliding window, regarding the code phase in the ZCZ sequence corresponding to the relevant peak as an initial phase if the judging results are yes, and otherwise, carrying out searching. According to the method, zero correlation windows with certain lengths are matched, the unique relevant peak with the certain width in the window is combined, average synchronization time is effectively lowered, high detection efficiency is guaranteed, and false alarm probability is reduced.

The invention provides a method and system for constructing a no-hit-zone bipolar frequency hopping code. The method for constructing the no-hit-zone bipolar frequency hopping code includes the steps that first, a no-hit-zone frequency hopping sequence NHZ is constructed; second, a Walsh sequence is constructed; third, the no-hit-zone frequency hopping sequence NHZ and the Walsh sequence are combined to form the no-hit-zone bipolar frequency hopping code. The method and system for constructing the no-hit-zone bipolar frequency hopping code have the advantages that according to the constructed no-hit-zone bipolar frequency hopping code, all codons are totally orthogonal as long as the delay between users is within a zero correlation zone, so that multi-site interference and beat noise of a two-dimensional coherent OCDMA system will be completely eliminated, and the near-far effect of the two-dimensional coherent OCDMA system can also be eliminated. Therefore, by means of the no-hit-zone bipolar frequency hopping code constructed through the method and system, a high-capacity two-dimensional coherent OCDMA system can be achieved, and the no-hit-zone bipolar frequency hopping code can be applied to an optical access network, an optical local area network, an optical code label switching network, an optical fiber sensor network and the like.

The invention provides a constructing method and system for the two-dimensional bipolar code of a zero-correlation region in time/frequency domain. The constructing method comprises the steps that A a time domain zero-correlation region spread-spectrum sequence LA with the zero-correlation region is constructed; B a single coincidence sequence in frequency domain is constructed; C a Walsh sequence is constructed; D the time domain zero-correlation region spread-spectrum sequence of the zero-correlation region is combined with the single coincidence sequence in frequency domain are combined to form a time/frequency domain zero-correlation region two-dimensional optical orthogonal code; and E the time/frequency domain zero-correlation region two-dimensional optical orthogonal code is combined with the Walsh sequence to form the two-dimensional bipolar code of the zero-correlation region in time/frequency domain. The method and the system have the advantages that multi-site interference and beat noise of a two-dimensional coherent OCDMA system are completely eliminated; the near-far effect of the two-dimensional coherent OCDMA system can be eliminated; the large-capacity two-dimensional coherent OCDMA system can be realized; and the method and the system can be applied to an optical access network, an optical local area network, an optical code tag switching network, a fiber optic sensor network and the like.

The invention belongs to the technical field of communication systems, and particularly relates to a method and a device using a deletion technology to generate a type-2 binary aperiodic Z complementary sequence pair signal pair. The method comprise the following steps: randomly selecting a binary golay complementary sequence pair (a_, b_) with an even length of N' as a seed pair; randomly selecting s positive integers ri, wherein i is greater than or equal to 1 and less than or equal to s; randomly selecting s positive integers dj, wherein j is greater than or equal to 1 and less than or equal to s; deleting the ri-th code element of the sequence a_ to obtain a sequence of which the length is N = N-s as e_; and deleting the dj-th code element of the sequence b_ to obtain a sequence of which the length is N = N-s as w. The sequence length and the zero-correlation region width of the type-2 binary aperiodic Z complementary sequence pair (e_, w_) obtained in the invention are adjustable,and the odd-length type-2 binary aperiodic Z complementary sequence pair reaching the maximum zero-correlation region width can be generated. Further, an implementable device is provided. The methodand the device can be applied to signal processing, communication systems, large-scale integrated circuit testing and the like.