High-precision interference alignment narrowband interference suppression algorithm for broadband private network system

A narrow-band interference and interference alignment technology, applied in the field of communication, can solve problems such as high complexity of recovery algorithms, uneven error distribution, and low estimation accuracy, and achieve the effects of improving BER performance, increasing accuracy, and reducing spectrum leakage

Active Publication Date: 2022-01-11
HARBIN INST OF TECH +1
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  • Summary
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  • Application Information

AI Technical Summary

Problems solved by technology

In recent years, some literatures have studied narrowband interference suppression based on compressed sensing, but this method has problems such as poor noise immunity and high complexity of restoration algorithms.
The estimation accuracy of the interference frequency estimation algorithm in the above literature is low and the error distribution is uneven, resulting in a large spectrum leakage after interference alignment

Method used

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  • High-precision interference alignment narrowband interference suppression algorithm for broadband private network system
  • High-precision interference alignment narrowband interference suppression algorithm for broadband private network system
  • High-precision interference alignment narrowband interference suppression algorithm for broadband private network system

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Experimental program
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specific Embodiment 1

[0071] according to figure 1 and figure 2 As shown, the present invention provides a high-precision interference alignment narrowband interference suppression algorithm for a broadband private network system, comprising the following steps:

[0072] Step 1: Use FFT to detect narrowband signal interference clusters on the in-band spectrum, start detection from low frequencies, and filter out interference clusters with interference. If there is no interference, perform baseband processing on the received signal in a traditional OFDM system;

[0073] Step 2: Model the form of narrowband interference as single-tone interference, and all interference clusters correspond to multiple single-tone interferences. The single-tone interference in each interference cluster is used to locate the frequency of the narrow-band interference signal in the interference cluster. The j corresponding to the maximum value of |Y(j)| in the interference cluster is denoted as m′, according to the ener...

specific Embodiment 2

[0131] according to Figure 6 to Figure 8 , aiming at improving the NBI frequency estimation accuracy and reducing the NBI spectrum leakage narrowband interference suppression problem in the OFDM-based broadband private network system group service of the present invention, a Monte Carlo simulation verification is carried out, and the relevant simulation parameters are set as shown in Table 1.

[0132] Table 1

[0133]

[0134] To compare the frequency estimation accuracy of CZT, Image 6 gives m=100, a=0.3, A 0 = 4, the spectrum near the interference frequency after FFT of the received signal and the spectrum refined by CZT. It can be seen from the figure that compared with the spectrum obtained by direct FFT, the spectrum peak after CZT refinement is closer to the actual interference frequency, and the interference frequency estimation based on CZT has higher accuracy.

[0135] In order to compare the impact of different fractional factors a on the system performance, ...

specific Embodiment 3

[0138] The NBI time-domain sampling of one OFDM symbol period at the receiving end is expressed as:

[0139]

[0140] Among them, t s is the sampling interval in the time domain.

[0141] After NBI undergoes FFT, the frequency domain interference at the kth subcarrier position can be expressed as:

[0142]

[0143] Pushed further:

[0144]

[0145] When a=0,

[0146]

[0147] At this time, the single-tone interference is orthogonal to the OFDM subcarrier, and the interference only affects the subcarrier labeled m, and has no influence on other subcarriers. A good effect can be obtained by using the frequency domain zeroing interference suppression method for the subcarrier m.

[0148] When a≠0,

[0149]

[0150] It can be seen that single-tone interference produces spectrum leakage to adjacent multiple subcarriers. A 0 =4, the monotone interference of the interference frequency integer factor m=100 is an example, the monotone interference spectrum corresp...

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Abstract

The invention is a high-precision interference alignment narrowband interference suppression algorithm for a broadband private network system. The present invention detects interference clusters and their numbers through a double threshold method, and performs interference suppression processing if they exist. The combination of FFT and CZT realizes the precise estimation of NBI frequency on the local spectrum, which improves the accuracy of NBI frequency estimation of group users affected by NBI; uses spectrum shift to realize the interference alignment between NBI and OFDM subcarriers, reducing NBI Spectrum leakage improves the BER performance of the OFDM broadband private network system in the presence of narrowband interference. The present invention improves the BER performance of the narrowband interference suppression algorithm of narrowband interference suppression in the frequency domain of the broadband private network system, and is useful for the coexistence and compatibility of the NB-IoT narrowband network and the broadband private network system in the 5G era, and improves the universality of the broadband private network system to the environment. Important theory and application value.

Description

technical field [0001] The invention relates to the technical field of communication, and is a high-precision interference alignment narrowband interference suppression algorithm for a broadband private network system. Background technique [0002] As an important part of wireless communication, private network communication with command and dispatch as its core business is developing rapidly all over the world. Industry users urgently need private networks to provide broadband services such as high-speed data, images, and videos. Broadband-based private network communication systems are imperative and urgent. In recent years, the research on broadband private network system based on 4G core technology OFDM has received extensive attention. Group business is the core business of broadband private network system. Improving the performance of group business has important theoretical significance and application value to promote the development of broadband private network sys...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H04L25/03
Inventor 宋志群张成文刘玉涛史军王彬胡旭东马千里张哲铭陈金龙刘柯池王世鹏孔杰
Owner HARBIN INST OF TECH
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