87 results about "Local spectrum" patented technology

The present invention increases the available spectrum in a wireless network by sharing existing allocated (and in-use) portions of the RF spectrum in a manner that will minimize the probability of interfering with existing legacy users. The invention provides interference temperature-adaptive waveforms, and a variety of physical and media access control protocols for generating waveforms based on measurement and characterization of the local spectrum. The invention measures the local spectrum at a receiving node, generates an optimal waveform profile specifying transmission parameters that will water-fill unused spectrum up to an interference limit without causing harmful interference to primary and legacy transmitters using the same frequency bands, and enables simultaneous transmit and receive modes at a multiplicity of transceivers in a wireless network. The invention also provides closed loop feedback control between nodes, co-site interference management, intersymbol interference mitigation, wide sense stationary baseband signaling and modulation, and power limited signaling for avoiding detection and interception.

Methods and systems for sharing white space with primary services and other emerging services are provided. Signal distribution within a specified location, such as a dwelling, is performed using a home gateway that identifies unused white space, reserves such white space spectrum, and delivers data to one or more devices at the respective location using the reserved spectrum. Signalling between the devices and the gateway is performed over a shared signalling channel, which enables the gateway to advise the devices from where and when to receive data. The gateway also uses a common spectrum reservation OFDM symbol to advise the neighbouring gateways of the local spectrum reservation.

The present invention increases the available spectrum in a wireless network by sharing existing allocated (and in-use) portions of the RF spectrum in a manner that will minimize the probability of interfering with existing legacy users. The invention provides interference temperature-adaptive waveforms, and a variety of physical and media access control protocols for generating waveforms based on measurement and characterization of the local spectrum. The invention measures the local spectrum at a receiving node, generates an optimal waveform profile specifying transmission parameters that will water-fill unused spectrum up to an interference limit without causing harmful interference to primary and legacy transmitters using the same frequency bands, and enables simultaneous transmit and receive modes at a multiplicity of transceivers in a wireless network. The invention also provides closed loop feedback control between nodes, co-site interference management, intersymbol interference mitigation, wide sense stationary baseband signaling and modulation, and power limited signaling for avoiding detection and interception.

The invention discloses a harmonic analysis method based on Kaiser self-convolution window dual-spectrum line interpolation FFT (Fast Fourier Transform) and a device thereof. The method comprises the following steps of sampling a signal: sampling a time-domain continuous signal, and discretizing to obtain an infinitely long discrete sequence; windowing a four-order Kaiser self-convolution window function: performing four-order Kaiser self-convolution window operation on the infinitely long discrete sequence; performing N-point FFT on a windowed and truncated signal to obtain the discrete spectrum of the signal; determining the peak parameter of the discrete spectrum: searching the local spectrum peak of each integer harmonic frequency around the integer harmonic frequency; and calculating a harmonic parameter: solving a coefficient alpha by adopting a discrete spectrum interpolation correction formula based on an LSM (Least Square Method), and calculating parameters such as a harmonic frequency, an amplitude, an initial phase angle and the like. Due to the adoption of the method, the fundamental and harmonic components of a tested signal can be detected rapidly and accurately, and accurate frequency measurement is realized; and the method is convenient for implementing an embedded system, and the tested signal can be detected continuously for a long time.

The invention relates to an improved double-threshold cooperative spectrum sensing method, which comprises the following steps that: a cognitive user in a cognitive radio system senses a local spectrum, compares and classifies sensed main user energy values, if the energy values are beyond two thresholds, can directly perform local judgment to obtain a hard judgment result whether a main user exists and send the result to a fusion center, if the energy values are between the two thresholds, the cognitive user needs to send the sensed main user energy values and signal to noise ratios to the fusion center, and the fusion center calculates a weight factor of each cognitive user according to the received signal to noise ratios and performs fusion judgment according to the received energy values to obtain a soft judgment result whether the main user exists; and the fusion center comprehensively processes the hard judgment result and the soft judgment result, and makes a final judgment whether the main user exists by using an 'or' rule. According to the method, the advantage of double-threshold cooperative spectrum sensing can be fully realized; and the spectrum sensing performance is improved.

Provided are a cognitive radio (CR) cooperative spectrum sensing method and a fusion center (FC) performing CR cooperative spectrum sensing. The CR cooperative spectrum sensing method includes receiving, at an FC, local spectrum sensing information about a predetermined frequency band from each of N secondary users (SUs) in a predetermined zone, determining, at the FC, the optimum number of SUs for determining whether the predetermined frequency band is being used by a primary user (PU) on the basis of the received local spectrum sensing information, and performing cooperative spectrum sensing on the basis of local spectrum sensing information received from the optimum number of SUs in the predetermined zone. The method is implemented by the FC. Accordingly, the method and FC find how many SUs are needed to determine that a frequency of a PU is being used in a corresponding-channel situation, thereby enabling efficient communication.

The invention discloses a communication key generation method and a secure channel selection method for a cognitive radio system, and belongs to the field of secure communication and information security in radio communication. A common available channel set is established according to a local spectrum pool of received and transmitted nodes, the quantity of channels of the channel set is at least equal to one, beacon signals with random initial phases are received and transmitted multiple times by the aid of channels which are sequentially selected from the available channel set, and phases of the received signals are detected and utilized for generating a random key element matrix according to reciprocity of wireless transmission characteristics of the same channels within a coherent time and differentiation of wireless transmission characteristics of different channels, and finally communication keys are acquired by fusion processing of the matrix. The communication keys are used for encrypting transmitted information and are also used as random seeds for selecting secure communication channels. The communication key generation method and the secure channel selection method have the advantages that interaction of the communication keys among the received and transmitted nodes through the channels is omitted, hidden dangers such as wiretapping, tampering and saturation attack from attackers can be eliminated, and commutation security of the cognitive radio system can be guaranteed.

The invention discloses a method and a device allocating distribution type spectrum resource, which relates to the technical field of radio. The invention aims to solve the problem that the distribution type network in the prior art can not realize dynamic allocation of discontinuous spectrum. The method for allocating distribution type spectrum resource comprises the following steps of: receiving request information, which carries a spectrum resource occupying condition list and parameters of the service to be transmitted at the sending end; acquiring an idle spectrum resource collection available for the service to be transmitted according to the received spectrum resource occupying condition list and the local spectrum resource occupying condition list, wherein the idle spectrum resource collection is the idle spectrum resource collection shared by the sending end and the transmitting end; and allocating at least one section of spectrum resource in the idle spectrum resource collection available for the service to be transmitted to the service to be transmitted according to the parameters of the service to be transmitted.

Apparatuses and methods for simultaneously operating as a wireless radio and monitoring the local frequency spectrum. For example, described herein are wireless radio devices that use a secondary receiver to monitor frequencies within the operating band and prevent or avoid interferers, including in particular half-IF interferers. The systems, devices, and methods described herein may adjust the intermediate frequency in a superheterodyne receiver to select an intermediate frequency that minimizes interference. In particular, described herein are apparatuses and methods that use a second receiver which is independent of the first receiver and may be connected to the same receiving antenna to monitor the geographically local frequency spectrum and may detect spurious interferers, allowing the primary receiver to adjust the intermediate frequency and avoid spurious interferes.

The invention relates to a cooperative spectrum sensing method capable of saving cost on network communication. The prior network communication has the defect of high cost. The method comprises the following steps: a cognitive radio user uses an energy detection technique to sense the spectrum of a target frequency range, thereby obtaining a local sensing result; a data fusion center collects andfuses the local sensing results of the cognitive radio users, and makes a judgment on the spectrum service conditions, thereby obtaining a cooperative sensing judgment result; and the data fusion center and the cognitive radio users communicate messages through a control channel, each cognitive radio user transmits the local spectrum sensing result, and the data fusion center transmits the cooperative sensing judgment result. On the premise of not reducing the cooperative sensing accuracy, the method of the invention reduces the cost on cognitive radio network communication. For the cognitiveradio users, the method reduces the transmission of unnecessary sensing results, saves the valuable energy and prolongs the service lives of batteries.

The invention relates to a reliability-based weighted collaboration spectrum detection method. The main steps are that each sensor node detects a local spectrum and gains respective local spectrum sensing reliability of the local spectrum sensing by making a comparison with an overall detection result. A threshold of the reliability can be calculated through a tail-cut average method by a fusion center which chooses a sensor node with the reliability greater than the threshold is chosen to participate in cooperation. The reliability of the sensor node is greater than the threshold. The reliability of the sensor node which is screened out is dealt in a normalization mode in order to gain a weighting coefficient of the sensor node in the cooperation. After the fusion center detects statistics and carried out weighting summation process on the node which participates in the cooperation, a result is compared with a judgment threshold of a system and judge whether a master user is occupying a frequency spectrum is occupied by a master user is judged. The reliability of the sensor node is updated after each detection process in order to prepare the next detection process. The method has the advantages of reducing effectively the complexity of the cooperation detection of a cognitive network, improving the performance of the spectrum detection and being equipped with a good robustness in a noise-fluctuation environment.

The invention discloses a selecting type cooperation spectrum sensing method based on double-threshold energy detection. The selecting type cooperation spectrum sensing method comprises the following steps: (1) in a master user signal detection stage, adopting a double-threshold energy detection method by various cognitive users in a cognitive radio system to carry out local spectrum sensing, if an energy value exceeds two thresholds, carrying out local judgment 'H0 or H1'by the cognitive users, and if the energy value is between the two thresholds, reserving the energy value as a primary energy detection value by the cognitive users; (2) in an initial detection result reporting stage, evenly distributing a master user frequency band by the cognitive users, adopting a selecting type strategy by the cognitive users to report initial detection results respectively to a fusion center, preventing cognitive detection results with unreliable parameters from being introduced, meanwhile, saving traditional exclusive control channel resources, adopting the equal gain criterion by the fusion center to carry out master user judgment on the received primary energy detection value, allowing the judgment result to be equivalent to a node strategy by the fusion center, and then adopting the 'or' criterion by the fusion center to make the final judgment whether a master user exists. The simulation results show that according to the selecting type cooperation spectrum sensing method based on the double-threshold energy detection, and on the premise that ROC properties are not lost, the exclusive control channel resources are effectively saved, and meanwhile higher detection efficiency can be obtained.

The invention discloses a novel rail train running part rolling bearing fault diagnosis method. Local spectrum feature extraction is realized by providing a sliding time window segmentation algorithm based on index smoothing prediction, and fault diagnosis of a rail transit train running part bogie rolling bearing is performed through combination of an improved Adaboost algorithm. With application of the technical scheme, the nonlinear and non-stationary real-time vibration data of the rail train running part can be effectively segmented and then a local spectrum diagram is constructed, and the intermediate point frequency of the local spectrum interval is selected to act as the feature vector of the sample so that the more accurate input is provided to a classifier, the method has high accuracy in the aspect of rolling bearing fault diagnosis, the accuracy of fault classification can be effectively guaranteed, and the problems of low accuracy and difficult fault classification of the existing method can be solved.

A system and method are provided for implementing a cloud based spectrum management scheme that enables Dynamic Spectrum Access (DSA) through rentals of available spectrum in a two-level analytics process for optimization. Primary spectrum holders as exclusive licensees of underused spectrum communicate with a global spectrum broker to place portions of their underused spectrum into an auction-based rental market on the condition that they can regain control of their spectrum when a need arises. Local spectrum brokers communicate with the global spectrum broker to bid for available spectrum to meet their temporary needs in time and place. The local spectrum brokers, in turn, administer local optimization schemes over their portion of the global region to ensure that an expected level of quality of service is provided to individual customers with whom the local spectrum brokers communicate. The disclosed brokering scheme, properly administered, provides an incremental step-wise approach to solving long-term spectrum shortage for wireless communications.

The invention relates to a cooperative frequency spectrum sensing method based on a fuzzy integral and optimization theory, which comprises the following steps of: respectively carrying out local frequency spectrum sensing by all sensing users and performing two assumptions according to the existence condition of a main user signal; respectively transmitting detecting statistical data to a fusing center; respectively setting two fuzzy integrators, four fuzzy measuring degrees and corresponding fuzzy evaluating methods for the two assumptions by the fusing center, respectively transmitting two different training sequences of the existence of the main user signal, obtaining an optimal numerical value of the four fuzzy measuring degrees by an optimization method and respectively calculating fuzzy integral values of all the sensing users in the two fuzzy integrators on the basis of the obtained optimal fuzzy measuring degree; and finally performing final judgment according to a preset judging policy. The invention leads a final judging result of the fusing center to fully consider the uncertainty of detecting results of all the sensing users by the fuzzy integral and optimization theory and greatly improves the detecting accuracy of the whole sensing radio system frequency spectrum.

Apparatuses and methods for simultaneously operating as a wireless radio and monitoring the local frequency spectrum. For example, described herein are wireless radio devices that use a secondary receiver to monitor frequencies within the operating band and prevent or avoid interferers, including in particular half-IF interferers. The systems, devices, and methods described herein may adjust the intermediate frequency in a superheterodyne receiver to select an intermediate frequency that minimizes interference. In particular, described herein are apparatuses and methods that use a second receiver which is independent of the first receiver and may be connected to the same receiving antenna to monitor the geographically local frequency spectrum and may detect spurious interferers, allowing the primary receiver to adjust the intermediate frequency and avoid spurious interferes.

The invention discloses a wireless multimedia sensing network video signal adaptive sampling and spectrum allocation method. The method comprises the following steps of: acquiring the video of a video signal source by use of a wireless network video camera or a video acquisition card; regarding the first acquired video frame as a reference frame; testing the sparsity of pixel blocks by use of compression sampling; performing compression sampling of the sparse blocks of all pixel blocks in continuous non-reference frames and spatially corresponding to the previous reference frame, and performing traditional sampling of the remaining part; performing independent local spectrum measurement by each cognitive radio apparatus; converting the obtained analogue signals into sparse sampling signals; adaptively changing the sparse sampling signals, and transmitting to a fusion center; estimating the joint power spectrum density through a joint reconfiguration algorithm; separately performing energy detection to obtain corresponding spectrum judging results; and fusing all individual judging results according to OR logic by the fusion center so as to judge whether a master user exists in the observed frequency band.

The invention discloses a carrier tracking method of a GNSS (Global Navigation Satellite System) receiver. The method comprises the following steps of: using two local intermediate frequency carriers with 9 degrees of phase difference to demodulate a received intermediate frequency signal; using a local spectrum spreading code to de-spread two baseband signals I and Q respectively; respectively multiplying the two de-spread baseband signals I1 and Q1 by a code count; obtaining two operation results I2 and Q2; calculating a product of the de-spread baseband signal I1 and the operation result Q2 and a difference between the de-spread baseband signal I2 and the operation result Q1; according to the difference, determining a frequency offset number; and adjusting the frequencies of the two local intermediate frequency carriers by using the frequency offset number. According to the carrier tracking method disclosed by the invention, only one set of intermediate frequency carriers is used, so that the circuit scale is reduced, and the circuit structure is simplified; an multiplying operation and an additive operation are only related in the carrier tracking process, therefore, the carrier tracking process can be completed through a basic multiplier and an adder, and the system cost is reduced.

The invention discloses a high-precision adaptive filtering FBG spectral rapid peak searching method. The method is characterized by according to an acquired central wavelength lambda0 of an FBG spectrum under an indoor environment, cutting FBG spectrum data to acquire an FBG spectrum data subset; carrying out energy maximum detection PMax on the FBG spectrum data subset and taking lambdaMax as a center and shifting 2.5nm to left and right sides respectively; selecting and constructing a spectrum energy array P[i] which participates in peak searching; carrying out adaptive zero phase filtering on the spectrum energy array P[i], calculating an optimal cutoff frequency, carrying out low pass filtering and acquiring a filtered array p<'>[i]; and using a Gauss fitting algorithm to carry out accurate peak searching on the filtered spectrum energy array p<'>[i] and acquiring an FBG spectrum accurate peak point. By using the method, the algorithm is simple and rapid, a participated peak searching data amount is less, the method is not influenced by a local spectrum noise and signal distortion, peak searching stability is good and precision is high. Under an extreme environment, FBG spectrum energy attenuation is intense so that a signal to noise ratio is low and peak searching can not be performed. By using the method, the above problem is solved. The method has positive practical significance for increasing measurement precision of a fiber grating sensor under a conventional usage environment and the extreme environment.

The invention discloses a cooperative spectrum detection method for cognitive radio based on a neural network, which comprises the following steps that: a cognitive user in a network unit has two states, namely a training period and a working period, and the cognitive user comprises a back propagation (BP) neural network module; the cognitive user in the training period carries out local spectrum detection, trains an own BP network by comparing detection results of a central node, predicts own correct detection probability, and does not participate in fusion; after the training period is over, the cognitive user enters the working period, uses the BP network to obtain a prediction value of the correct detection probability, carries out the local spectrum detection and participates in the fusion; the central node takes the prediction value of the correct detection probability of each cognitive user as reliability, and fuses each local detection result to obtain a final detection result; and the cognitive user in the working period judges whether the BP network is required to be corrected according to a particular case. In the method, factors of hidden terminal and instability of an electromagnetic environment are taken into full consideration in combination with the neural network and cooperative spectrum detection, so that the spectrum detection performance of a cognitive radio system is improved.

The present invention relates to a remote-sensing image fusion method based on image local spectral characteristics. Said method combines local correlation moment and local variance of remote-sensing image to make fusion, on the basis of making multispectral image undergo the process of IHS transformation makes I component obtained after transformation and high-spectral image undergo the process of histogram matching treatment, then makes the matched I component and high-spectral image respectively undergo the process of vavelet transformation. For low-frequency component obtained after wavelet decomposition said method adopts the fusion criterion based on local normalized correlation moment to make fusion, and for high-frequency component it adopts the fusion criterion based on variance to make fusion, then reconstructes all the wavelet components after fusion to obtain new I componnet, finally, uses new I component and original components of H and S to make IHS inverse transformation so as to obtain the fusion result.

The invention relates to a cooperation spectrum sensing method based on network encoding. The method comprises the following steps of: carrying out local spectrum sensing by a cognition user, and selecting a cognition node which is not sensed but has good receiving property as a relay node; carrying out interaction on the information of the cognition user by the cognition node used as the relay node through network encoding; transmitting the sensing information to an integration center by the cognition user through space time encoding after obtaining the sensing information of other users; and judging the integration by the integration center by using the results of network decoding and space time decoding. In the invention, the relay nodes with good property is selected, network encodingis used on the relay nodes, which enhances the probability of the interaction success of the cognition information; and the sensing information after interaction by the cognition user is sent throughthe space time encoding, thereby enhancing the reliability of the sensing information transmission, and furthermore enhancing the property of the cooperation spectrum sensing.

The invention discloses a method for identifying affiliations of spectrum lines of elements by laser-induced breakdown spectroscopy. Through selecting the size of a range of a spectrum band to be identified as the size of an analysis window, a local spectrum to be identified in the window is combined with a standard library of emitting spectrum lines of different elements, and the spectrum lines of the elements in the analysis window are accurately identified by local correlation analysis; and then through setting a movement step of the analysis window, the full-spectrum scanning analysis on a measuring spectrum is completed, and thus the affiliations of the spectrum lines of different elements in the measuring spectrum are identified. The method has the characteristics of high identification speed, high accuracy rate, high automation degree and the like, is completely realized in a computer system because of no artificial identification interference factors, and effectively solves the problems of speed and accuracy of identifying the affiliations of the spectrum lines of the elements when data of an existing laser-induced breakdown spectroscopy is processed, and automation degree of identifying the spectrum lines.

The invention discloses a polarization-state phase-adjustable wide-spectrum reflecting mirror. Three-dimensional integrated precise regulation and control of spectrum, polarization state and phase of the reflecting mirror is realized through optimal combination of a metal film material and various dielectric film materials. According to the reflecting mirror, high reflectivity in wide spectrum range is realized by the metal film material; enhancement of local spectrum reflectivity of the reflecting mirror and control of polarization sensitivity are realized by a periodic 1 / 4 full dielectric reflective film stack; precise regulation and control of the reflecting phase of the reflecting mirror is realized by multiple layers of irregular dielectric films. The reflecting mirror has the characteristics of wide reflecting spectrum range, precise and adjustable reflecting polarization state and phase, capability of enhancing local spectrum reflectivity and the like.

The invention belongs to the technical field of communications, and especially relates to a cooperative spectrum sensing implementation scheme based on a cognitive radio technology in a wireless communication system. The invention provides a perceptual information fusion method based on energy detection, wherein after local spectrum sensing based on energy detection of all cognitive nodes is completed, a fusion center and all users participating in spectrum sensing cognition adopt the perceptual information fusion method provided by the invention to realize fusion of perceptual information, therefore, the accuracy of a spectrum sensing result and the scope of spatial application can be improved, the time overhead of reporting a local perception judgment result to the fusion center by all cognitive nodes can be reduced and the cooperative sensing performance better than a traditional cooperative perception fusion rule can be obtained.

The invention discloses a soft-decision spectrum sensing method based on compression non-reconstruction. The method mainly comprises the steps that firstly, a sensing model is established, secondary users establish a local spectrum sensing model, a binary presumptive model is adopted, and the energy detecting method is adopted under the non-cooperative mode; secondly, compressed sampling is carried out, and the secondary users utilize a two-dimensional Gaussian measurement matrix to carry out compressed sampling on a receiving signal; thirdly, under the situation that the compressed sampling data are not reconstructed, the secondary users directly utilize the compressed sampling data to establish the test statistics amount based on energy, whether a primary user exists or not is not judged, and the test statistics amount is transmitted to a fusion center; fourthly, the soft decision of the fusion center is carried out, and after the fusion center collects the test statistics amount sent by all the secondary users, the unified test statistics amount is established and compared with the detecting threshold value, and a final decision result is given.

A method for spectrum sensing for cognitive radio includes performing a process of local spectrum sensing using receive beamforming and energy detection at each of a plurality of secondary users included in a cognitive radio network, wherein the process of local spectrum sensing decides between two hypotheses corresponding to absence and presence of a primary user, the two hypotheses being formulated using a primary user signal, a plurality of co-channel interferences, and sensing noise, the primary user signal, the plurality of co-channel interferences, and the sensing noise being received at each of the plurality of secondary users, and a set of beamforming weights of the receive beamforming is determined by optimizing a probability of detection and constraining a probability of false alarm.

The invention provides a handheld fluorescence microscope. A local spectrum light source, a first optical filter, a second optical filter and an image sensing circuit are disposed in a shell of the handheld fluorescence microscope. The local spectrum light source is used for generating first light. The first optical filter is used for filtering the first light to generate second light. The second optical filter is used for filtering fluorescence generated by a sample irradiated by the second light so as to generate fourth light. The image sensing circuit is used for receiving the fourth light to generate fluorescent images. A light mask is disposed at one end of the shell and used for enclosing the sample so as to decrease or prevent light from entering the image sensing circuit from outside of the light mask. The second light irradiates an optical path of the sample, the optical path does not overlap with an optical path of the fluorescence which enters the second optical filter from the sample, and no splitter is disposed on the optical path of the fluorescence entering the second optical filter or the optical path of the fourth light entering the image sensing circuit. The handheld fluorescence microscope is capable of normally detecting fluorescent images in general environments.

The invention discloses a clustering cooperative spectrum sensing hard fusion method for a cognitive wireless sensor network. All cognitive sensing nodes are clustered firstly, a cluster head of each cluster is selected, the cognitive sensing nodes achieve spectrum sensing according to the signal energy of a master user, local spectrum sensing information is acquired, then first-time fusion is carried out on all the local spectrum sensing information in the clusters through the cluster heads, the spectrum sensing information of the corresponding cluster is acquired, and finally fusion is carried out on the spectrum sensing information of all the clusters through a fusion center to obtain the final spectrum sensing information. Through cluster head screening and two times of fusion, the computation burden of the fusion center is reduced, and the effect of fast judging whether frequency spectrum is free or not and improving the correct probability of detection is achieved.