A channelized multicarrier interference avoidance frequency selection method

Abstract

The application discloses a kind of multi-carrier interference avoidance frequency selection methods based on channelization, belong to wireless communication technical field.The present application is based on the frequency domain characteristics of multi-carrier signal, using channelization method will be divided into multiple channels with the working frequency band, and combining zero intermediate frequency receiver, electromagnetic environment is sampled and analyzed, by determining each channel energy value, the minimum interference subcarrier frequency point is selected to communicate, when interference is encountered in communication process, according to the feedback of receiver dynamically adjusts frequency selection method.The present application can improve the anti-interference ability of communication system, and improve spectrum utilization efficiency and communication reliability by reducing the complexity of frequency switching and the iteration number of frequency selection.

Description

TECHNICAL FIELD

[0001] The application relates to a channel-based multi-carrier interference avoidance frequency selection method and belongs to the technical field of wireless communication. BACKGROUND

[0002] The rapid development of mobile communication technology and the popularity of intelligent terminals promote the wide application of multimedia devices, and the efficient use of spectrum resources becomes a key problem in the field of wireless communication. Multi-carrier communication technology occupies an important position in wireless communication systems due to its high spectrum efficiency, easy equalization and strong anti-multipath interference capability.

[0003] Multi-carrier signals occupy multiple frequency bands in the frequency domain and the adjacent frequency bands are separated by an integer multiple of the bandwidth value, and are more susceptible to interference. The interference of multi-carrier signals not only affects the communication quality, but also causes communication interruption and information loss. The traditional interference avoidance method has the problems of high complexity and large amount of calculation when applied in multi-carrier signals, and it is difficult to meet the actual application requirements. In order to improve the reliability and stability of the communication system, how to effectively avoid interference becomes a problem to be solved. SUMMARY

[0004] In order to solve the problems of the traditional interference avoidance method applied in multi-carrier signals, the purpose of the present application is to provide a channel-based multi-carrier interference avoidance frequency selection method. The working frequency band of the multi-carrier signal is processed by channelization, the entire frequency band is uniformly divided into several channels, the electromagnetic environment signal is sampled by a zero intermediate frequency receiver, the energy of each channel is calculated, the sub-carrier frequency point with the minimum interference is selected, and the optimal frequency point set is formed. The optimal sub-carrier frequency point is effectively selected in a complex electromagnetic environment, and the performance and reliability of the multi-carrier communication system are improved.

[0005] The purpose of the present application is realized by the following technical scheme:

[0006] A channel-based multi-carrier interference avoidance frequency selection method determines the working frequency band and the center frequency point of the multi-carrier signal, determines the number of channels required for channelization in combination with the sub-carrier bandwidth and the minimum adjacent sub-carrier spacing, samples the electromagnetic environment by a zero intermediate frequency receiver, uniformly divides the entire frequency band into multiple channels, selects the starting channel and step-determines the candidate sub-carrier frequency point, determines the channel energy occupied by the sub-carrier corresponding to the candidate sub-carrier frequency point by the receiver, obtains the optimal sub-carrier frequency point set, and adjusts the frequency selection strategy according to the feedback information of the receiver when interference occurs in the communication process. The transmitter selects the sub-carrier frequency point with the minimum interference for communication, and specifically includes the following steps:

[0007] Step 1: Determine the parameters of communication;

[0008] determining a working frequency band [f1, f2], a center frequency f0 of the working frequency band, a subcarrier bandwidth B, a minimum adjacent subcarrier spacing BI, and a channel number K;

[0009] A channel bandwidth RBW is shown in equation (1):

[0010] RBW = (f2 - f1) / K (1)

[0011] The channel number K satisfies that the subcarrier bandwidth B and the minimum adjacent subcarrier spacing BI are integer multiples of the channel bandwidth RBW, as shown in equations (2) and (3):

[0012] B = p · RBW (2)

[0013] BI = q · RBW (3)

[0014] wherein p is a ratio of the subcarrier bandwidth B to the channel bandwidth RBW, and q is a ratio of the minimum adjacent subcarrier spacing BI to the channel bandwidth RBW;

[0015] Step two: sampling the electromagnetic environment at zero intermediate frequency, and performing channelization processing on a spectrum of the sampled signal;

[0016] The electromagnetic environment is sampled by a zero intermediate frequency receiver, and channelization processing is performed on a spectrum of the sampled signal, so that the entire frequency band [f1, f2] is uniformly divided into K channels, and the channels are numbered from low frequency to high frequency as k, k = 0, 1,..., K-1; the initial channel number of the frequency selection channel is i = 0;

[0017] Step three: determining candidate subcarrier frequencies;

[0018] Extracting a power spectrum density feature of the power spectrum density data, and determining candidate subcarrier frequencies according to the extracted power spectrum density feature;

[0019] Taking the i-th channel as a starting channel, the i + p / 2 - 1-th channel as a first candidate subcarrier frequency, and taking q as a channel step to find the remaining available subcarrier frequencies, a total of mi, as shown in equation (4):

[0020]

[0021] Step four: determining a sum of channel energies occupied by subcarriers and a minimum sum of subcarrier channel energies;

[0022] Based on the candidate subcarrier frequencies determined in step three, a sum of channel energies occupied by subcarriers is determined;

[0023] Determine the channel energy occupied by the subcarriers corresponding to the mi frequency points, sort the channel energy of the mi candidate subcarriers in ascending order, and select the top N subcarrier frequency points of the sorted results. At this time, the sum Hi of the channel energy of the selected N subcarriers is the smallest, and the channel Ci corresponding to the N subcarrier frequency points at this time is obtained, as shown in Equation (5):

[0024] Ci={ki, 1, ki, 2,..., ki, N} (5)

[0025] Where N is the number of subcarriers in the multicarrier signal, and ki is the subcarrier frequency;

[0026] Step 5: Determine the minimum sum of subcarrier channel energies and the corresponding channel;

[0027] Iterate through all channels as the starting channel, determine the sum Hi of the corresponding subcarrier channel energies, find the minimum value in the set Hi, and the channel C corresponding to the N subcarrier frequency points at this time. final As shown in equation (6):

[0028] C final i = {k final i,1,k final i, 2, ..., k final i, N} (6)

[0029] Where, k final The subcarrier frequency corresponding to the minimum value of the Hi set;

[0030] Step Six: Determine the frequency selection for multi-carrier interference avoidance;

[0031] The subcarrier frequency point value is determined based on the channel corresponding to the subcarrier frequency point in step five, which is the channelization-based multi-carrier interference avoidance frequency selection;

[0032] It also includes step seven, in which the multi-carrier transmitter sends multi-carrier signals according to the corresponding frequency points based on the subcarrier frequency points obtained in step six. Under a given spectrum environment, it can avoid interference in the electromagnetic environment, reduce the impact of interference on communication, and improve the performance and reliability of the multi-carrier communication system.

[0033] Beneficial effects:

[0034] 1. The present invention provides a channelization-based multi-carrier interference avoidance frequency selection method, which divides the frequency band of multi-carrier signals using a channelization method, and combines a zero-IF receiver to sample the electromagnetic environment in real time. It achieves effective frequency selection with fewer iterations, solves the problems of low spectrum utilization and high implementation complexity in traditional multi-carrier interference avoidance strategies, and improves communication stability and spectrum utilization efficiency.

[0035] 2, the method selects the subcarrier frequency point with the minimum interference to communicate, and adjusts the frequency selection method in time when interference occurs, thereby reducing the complexity and time consumption of frequency switching, improving the anti-interference ability and overall performance of communication while maintaining the reliability of communication. BRIEF DESCRIPTION OF DRAWINGS

[0036] Figure 1 The flow chart of the method for selecting frequency based on channelization to avoid multi-carrier interference;

[0037] Figure 2 The spectrum sensing diagram based on channelization in the embodiment;

[0038] Figure 3 The frequency selection diagram based on channelization to avoid multi-carrier interference in the embodiment. DETAILED DESCRIPTION

[0039] In order to better illustrate the purposes and advantages of the present application, the content of the application will be further described below in combination with the drawings and examples.

[0040] Embodiment 1:

[0041] In the ground multi-carrier communication system, the transmitter adopts channelization for spectrum sensing to select a suitable subcarrier frequency point for transmitting multi-carrier signals, and the method for selecting frequency based on channelization to avoid multi-carrier interference is applied, as shown in Figure 1 The method comprises the following steps:

[0042] Step 1: Determine the parameters of communication;

[0043] Determine the working frequency band [f1, f2], the working frequency band center frequency f0, the subcarrier bandwidth B, the minimum adjacent subcarrier spacing BI, and the channel number K;

[0044] In the embodiment, the working frequency band is [f01, f02] = [1872 MHz, 2128 MHz], the working frequency band center frequency is f0 = 2 GHz, the subcarrier bandwidth B0 = 4 MHz, the minimum adjacent subcarrier spacing BI0 = 4 MHz, and the working frequency band [f01, f02] is divided into K = 8192 channels;

[0045] The channel bandwidth RBW is shown in formula (1):

[0046] RBW = (f2-f1) / K (1)

[0047] The channel number K satisfies that the subcarrier bandwidth B and the minimum adjacent subcarrier spacing BI are integer multiples of the channel bandwidth RBW, as shown in formula (2) and formula (3):

[0048] B = p RBW (2)

[0049] BI = q RBW (3)

[0050] wherein p is the ratio of the subcarrier bandwidth B to the channel bandwidth RBW, and q is the ratio of the minimum adjacent subcarrier spacing BI to the channel bandwidth RBW;

[0051] In the embodiment, the channel number K = 8192, the channel bandwidth RBW = 31.25 kHz, p = 128, and q = 128;

[0052] Step two: sampling the electromagnetic environment with zero intermediate frequency, and performing channelization processing on the sampled signal;

[0053] Collecting time domain data signals from sensors and data collection devices, the time domain data signals collected in the electromagnetic environment contain noise and interference, pre-processing the time domain data signals to remove direct current components, band-pass filtering to remove low frequency drift and high frequency noise, applying a window function to reduce spectral leakage, converting the time domain data signals to the frequency domain through fast Fourier transform, determining the power spectral density of the frequency domain data signals, and analyzing the frequency components and energy distribution of the frequency domain data signals;

[0054] Performing channelization processing on the sampled signal, dividing the entire frequency band [1872 MHz, 2128 MHz] into 8192 channels uniformly, the channels are numbered from low frequency to high frequency as k, k = 0, 1,..., K-1, let the initial channel number of the selected frequency channel i = 0;

[0055] The result of channelized spectrum sensing is shown in Figure 2 The yellow curve represents the spectrum result, and the Y axis represents the power, the higher the peak value represents the greater the interference;

[0056] Step three: determining the candidate subcarrier frequency point;

[0057] Extracting the power spectral density feature of the power spectral density data, and determining the candidate subcarrier frequency point according to the extracted power spectral density feature;

[0058] Taking the lth channel as the starting channel, the i+p / 2-1th channel as the first candidate subcarrier frequency point, and taking q as the channel step to find the remaining available subcarrier frequency points, a total of mi, as shown in equation (4):

[0059]

[0060] Step four: determining the channel energy occupied by the subcarrier and the sum of the channel energies of each subcarrier;

[0061] Based on the candidate subcarrier frequency points determined in step three, the sum of channel energy occupied by each subcarrier is determined;

[0062] The channel energy occupied by the mi frequency points corresponding to the subcarriers is determined, the mi candidate subcarrier channel energy is sorted in ascending order, and the first 8 subcarrier frequency points of the sorting result are selected. At this time, the sum of the channel energy of the 8 selected subcarriers Hi is the smallest, and the channel Ci corresponding to the 8 subcarrier frequency points at this time is obtained, as shown in formula (5):

[0063] Ci = {-64MHz, -60MHz, -56MHz, -52MHz, -48MHz, -44MHz, -40MHz, -36MHz} (5)

[0064] Step five: determine the minimum value of the sum of subcarrier channel energy and the corresponding channel;

[0065] All channels are traversed as starting channels, the corresponding subcarrier channel energy sum Hi is determined, the minimum value in the Hi set is found, and the channel C corresponding to the 8 subcarrier frequency points at this time final , as shown in formula (6):

[0066] C final = {-60MHz, -50MHz, -46MHz, -16MHz, -12MHz, 20MHz, 24MHz, 40MHz} (6)

[0067] Step six: determine the multi-carrier interference avoidance frequency selection;

[0068] According to the subcarrier frequency point value corresponding to the channel in step five, the multi-carrier interference avoidance frequency selection based on channelization is determined;

[0069] In the embodiment, the multi-carrier interference avoidance frequency selection result is as shown in Figure 3 , the red box represents the candidate frequency, the width of the red box represents the bandwidth of the signal, and the candidate frequency of the red box is offset from the interference frequency of the yellow box, which represents that the frequency selection result can avoid large interference in the signal;

[0070] It also includes step seven, according to the subcarrier frequency point value obtained in step six, the multi-carrier transmitter transmits multi-carrier signals according to the corresponding frequency points, which can avoid interference in the electromagnetic environment under the given spectrum environment, reduce the influence of interference on communication, and improve the performance and reliability of the multi-carrier communication system.

[0071] The embodiment applies a channel-based multi-carrier interference avoidance frequency selection method of the application, divides the frequency band of the multi-carrier signal into 8192 segments by using a channelization algorithm, combines the real-time sampling of the electromagnetic environment by the zero intermediate frequency receiver, realizes frequency selection through a small number of iteration times, reduces the time complexity of the system to O(n2), solves the problems of low spectrum utilization and high implementation complexity in the traditional multi-carrier interference avoidance strategy, and the selected C final ={-60MHz, -50MHz, -46MHz, -16MHz, -12MHz, 20MHz, 24MHz, 40MHz} frequency point can avoid the position of the transmission signal in the channel, effectively improves the stability and spectrum utilization efficiency of communication; by determining the energy values of each channel, selecting the sorted minimum energy value sequence H1={-42.45dBm, -43.15dBm, -48.56dBm, -47.12dBm, -44.54dBm, -43.11dBm, -42.29dBm, -49.77dBm}, and selecting the subcarrier frequency point with the minimum interference energy for communication, that is, selecting the frequency point C final ={-60MHz, -50MHz, -46MHz, -16MHz, -12MHz, 20MHz, 24MHz, 40MHz}, and adjusting the frequency selection method in time when interference occurs, while maintaining the reliability of communication, reducing the complexity and time consumption of frequency switching, making the system signal-to-noise ratio rollback less than 3dB, and improving the overall performance of system communication.

[0072] The above specific description further details the purpose, technical solution and beneficial effects of the application, and it should be understood that the above description is only a specific embodiment of the application and is not used to limit the protection scope of the application, and any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the application should be included in the protection scope of the application.

Claims

1. A channelized based multicarrier frequency selection method for interference avoidance, characterized by: By determining the working frequency band and the center frequency point of the multi-carrier signal, combining the sub-carrier bandwidth and the minimum adjacent sub-carrier spacing, the number of channels required for channelization is determined, the electromagnetic environment is sampled by the zero intermediate frequency receiver, and the entire frequency band is uniformly divided into multiple channels, the starting channel is selected and the selected sub-carrier frequency point is determined by stepping, the channel energy occupied by the sub-carrier corresponding to the selected sub-carrier frequency point is determined by the receiver, and the optimal sub-carrier frequency point set is obtained. In the communication process, when interference occurs, the transmitter adjusts the frequency selection strategy according to the feedback information of the receiver, selects the sub-carrier frequency point with the minimum interference for communication, and specifically includes the following steps: Step one: determine the parameters of communication; Determine the communication system working frequency band [f1, f2], the working frequency band center frequency f0, the sub-carrier bandwidth B, the minimum adjacent sub-carrier spacing BI, and determine the channel number K; The channel bandwidth RBW is shown in formula (1): RBW=(f2-f1) / K (1) The channel number K satisfies that the sub-carrier bandwidth B and the minimum adjacent sub-carrier spacing BI are integer multiples of the channel bandwidth RBW, as shown in formula (2) and formula (3): B=p·RBW (2) BI=q·RBW (3) Wherein, p is the ratio of the sub-carrier bandwidth B to the channel bandwidth RBW, and q is the ratio of the minimum adjacent sub-carrier spacing BI to the channel bandwidth RBW; Step two: zero intermediate frequency sampling of electromagnetic environment, and channelization processing of sampling signal spectrum; The electromagnetic environment is sampled by the zero intermediate frequency receiver, and the sampling signal spectrum is channelized, the entire frequency band [f1, f2] is uniformly divided into K channels, and the channels are numbered from low frequency to high frequency k, k=0, 1,…, K-1; The initial channel number of the frequency selection channel is i=0; Step three: determine the selected sub-carrier frequency point; Extract the power spectrum density feature of the power spectrum density data, and determine the selected sub-carrier frequency point according to the extracted power spectrum density feature; Take the i-th channel as the starting channel, the i+p / 2-1-th channel as the first selected sub-carrier frequency point, and find the remaining selected sub-carrier frequency points with q as the channel step, a total of mi, as shown in formula (4): Step four: determine the channel energy occupied by the sub-carrier and the sum of the minimum sub-carrier channel energy; Based on the selected sub-carrier frequency point determined in step three, the sum of the channel energy occupied by each sub-carrier is determined; Determine the channel energy occupied by the sub-carrier corresponding to the mi frequency points, sort the mi selected sub-carrier channel energy in ascending order, select the first N sub-carrier frequency points of the sorting result, at this time the sum of the N selected sub-carrier channel energy Hi is the minimum, and the channel Ci corresponding to the N sub-carrier frequency points at this time is obtained, as shown in formula (5): Ci={ki,1,ki,2,…,ki,N} (5) Wherein, N is the number of sub-carriers of the multi-carrier signal, and ki is the sub-carrier frequency; Step five: determine the minimum value of the sum of the sub-carrier channel energy and the corresponding channel; Traverse all channels as the starting channel, determine the sum of corresponding subcarrier channel energy Hi, find the minimum value in the Hi set, and the channel C corresponding to the N subcarrier frequency points at this time final As shown in formula (6): C final i = {k final i,1,k final i,2,...,k final i,N} (6) wherein k final i is the minimum value in the set Hi, the corresponding subcarrier frequency; Step six: determine the multi-carrier interference avoidance frequency selection; According to the sub-carrier frequency point value corresponding to the channel in step five, the sub-carrier frequency point value based on channelization is determined, which is the multi-carrier interference avoidance frequency selection.

2. A channelized multicarrier frequency selection method for interference avoidance as claimed in claim 1, characterized by: Step seven, according to the sub-carrier frequency point value obtained in step six, the multicarrier transmitter sends multicarrier signals according to the corresponding frequency points, and in a given frequency spectrum environment, interference in the electromagnetic environment can be avoided, the influence of interference on communication is reduced, and the performance and reliability of the multicarrier communication system are improved.

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