37results about How to "Good cross-correlation" patented technology

An improved generation and use of Positioning Reference Signals (PRS) are disclosed. The method generates PRS to be used in a wireless Orthogonal Frequency Division Multiplexing (OFDM) communication system. According to the invention, the method includes the steps of : - determining a time-frequency pattern of Resource Elements (REs) to be used for transmitting the PRS, wherein the time- frequency pattern includes at least two OFDM symbols, and - assigning, for each one of the at least two OFDM symbols, respectively, a value to each one of a number of the REs being within that OFDM symbol, wherein - the values being assigned to the number of REs correspond to elements in a modulation sequence having a length being equal to the number of REs, and are to be used for modulating OFDM subcarriers corresponding to the REs within that OFDM symbol.

The present invention provides a synchronization sequence transmission method, synchronization detection method and device. The transmission method includes: setting a target synchronization sequence with good autocorrelation characteristics; wherein, intercepting in the time domain or frequency domain of the target synchronization sequence The obtained at least one sequence is a sub-synchronization sequence, the sub-synchronization sequence has good autocorrelation characteristics and the sub-synchronization sequences have good cross-correlation characteristics; the target synchronization sequence is sent to the terminal; the embodiment of the present invention For terminals with different bandwidths or different carrier intervals, after the base station sends the same target synchronization sequence, the terminal can intercept the corresponding sub-synchronization sequence according to its own needs for synchronization detection, which not only ensures the accuracy of synchronization detection, but also improves the target Scope of application of the synchronization sequence.

The invention provides an underwater acoustic communication synchronization method based on a Zadoff-Chu sequence and an OFDM technology. The method comprises the following steps of: generating to-be-transmitted signals through the OFDM technology, setting a length N of the Zadoff-Chu sequence to be the number of subchannels of OFDM; generating two segments of identical Zadoff-Chu sequences ZC-sq1 and ZC-sq2 with the length N by the same root sequence, adding the two segments of sequences to the front end of an OFDM signal, and adding one segment of protective interval with the length Ng between the two segments of sequences; respectively capturing the signal through two time windows of which the length is N, and judging whether a peak value greater than a threshold value Delta exists in correlation operation result; respectively locating the peak values greater than the threshold value Delta in the correlation operation result, taking a peak value position of which the peak value is greatest as the peak value position searched this time, respectively recording as N1 and N2; judging whether the distance between the N1 and the N2 is approximate to N+Ng; acquiring signals again and taking N2+Ng as a starting point of an OFDM signal data segment, and thereby completing synchronization. The underwater acoustic communication synchronization method provided by the invention improves precision, reliability and accuracy of synchronization.

The invention discloses a controllable test vector generator based on a linear feedback shift register (LFSR). The controllable test vector generator comprises three sections: 1, a control code sequence generation section comprising a counter and a memory; 2, a sequence pseudo random test vector sequence generation section comprising a inscribe LFSR; 3, a feedback network section formed by n-1 bit input or a non-gate NOR and an exclusive-OR gate XORfb. Depending on the test vectors required to be generated, the control code sequence is acquired, wherein the control code sequence is stored in the memory and is provided for controlling a run of the inscribe LFSR, such that the sequence or jump output pseudo random sequence of the inscribe LFSR is adopted as the test vector. With the present invention, only the control code memory, the counter, the feedback network section formed by the n-1 bit input or the non-gate NOR and the exclusive-OR gate XORfb, and a control exclusive-OR gate XORCTRL are added on the base of the inscribe LFSR, such that hardware expense is few, and test cost is low.

The invention discloses a pseudo random sequence generation method for wireless sensor network nodes and an application method thereof, wherein the pseudo random sequence generation method for the wireless sensor network nodes comprises the following steps: step S101: inputting any prime number p and cardinal number R; step S102: setting an initial value of x to be the cardinal number R, initializing i to be 1, and initializing a random sequence S; step S103: setting an intermediate variable t, wherein t is equal to mod(x, p); step S104: assigning S(i), wherein S(i) is equal to floor(x / p); step S105: amending the value of x, wherein x is equal to t*R+S(i), amending the value of i, i is equal to i+1; step S106: judging whether the length of the random sequence S is equal to the length of the random sequence C, if so, carrying out the next step; if not, returning to the step S103: step S107: outputting the random sequence, S is equal to {S(1), S(2),..., S(i)}. New D-sequence generated by the method changes the limited cycle period of original (1 / p)RD-sequence so as to enlarge the sequence length; the method is more sensitive for disturbance, and has extremely good autocorrelation, cross correction and probability distribution characteristic.

An orthogonal narrow-band waveform design method oriented to cooperative spectrum sensing, and the invention relates to an orthogonal narrow-band waveform design method oriented to cooperative spectrum sensing. The purpose of the invention is to solve the problems that the existing waveform design method has no limitation on side lobe, low power utilization rate and poor waveform orthogonality. Realized by the following technical solutions: Step 1, select chirp base signal x(t); Step 2, use x(t) to carry out translation and superposition, respectively by two different superposition coefficient sets h1(l) and h2 whose length is 27 (l) Generate s1(t) and s2(t); step 3, define the power spectrum constraint function, convert the design problem of s1(t) into a mathematical optimization problem, and use the CVX toolkit to solve the best stacking coefficient set to obtain step 4 : define the threshold value of cross-correlation of orthogonal signals, convert the design problem of s2(t) into a mathematical optimization problem, and use the CVX toolkit to solve the best stacking coefficient set to obtain the present invention and apply it to the field of spectrum sensing.