WO2006102793A1

WO2006102793A1 - A method of detecting illegal occupancying frequency signal in radio communication network

Info

Publication number: WO2006102793A1
Application number: PCT/CN2005/000407
Authority: WO
Inventors: Yanwei Wu
Original assignee: Zte Corporation
Priority date: 2005-03-29
Filing date: 2005-03-29
Publication date: 2006-10-05
Also published as: CN101167377A; CN101167377B

Abstract

A method of detecting illegal occupying frequency signal in radio communication network, comprising: determining the detecting objects in network according to the demand of detecting interference signal; keeping the detecting objects not being distributed to any link; among the detecting objects, detecting the received signal’s intensity; comparing the received signal’s intensity with the signal’s background noise, if the difference between the received signal’s intensity and the signal’s background noise exceeds predetermined threshold, it indicates there is illegal occupying frequency signal in the network. With the method according to the present invention, we can detect if there is the interference of the illegal occupying frequency signal in the current radio communication network at any time, without the influence of the legal communication. The method according to the present invention can be used to TDMA system of TDD or FDD, and the broadband data communication network based on OFDM/OFDMA.

Description

Method for detecting illegally occupied frequency signals in a wireless communication network

The present invention relates to the field of wireless communications, and in particular to a method for detecting an illegally occupied frequency signal in a wireless communication network, and is particularly suitable for a time division multiple access cellular communication system (such as GSM, TD-SCDMA) and broadband wireless based on OFDM/OFDMA. Access to the network (such as 802.16). Background technique

According to the relevant standards, wireless communication networks are established at specified frequency points or frequency bands. These specified frequency points or frequency bands are legal frequency points or frequency bands, and their right to use is limited by legal documents. Only authorized operators have the right to use the legal frequency or frequency band. Any unauthorized unit or individual using these frequency points or frequency bands is illegally occupied.

However, during the construction of the wireless communication network and the operation of the network, the wireless communication network is often interfered with by illegally occupying the frequency signal. When the interference of the illegally occupied frequency signal is serious, the local wireless communication network may not work normally. Usually, operators of wireless communication networks find it difficult to locate and locate the illegal occupied frequency signals. In order to prove the existence of illegal occupied frequency signals and find interference sources, a large amount of human resources and monitoring equipment are usually required.

In the prior art, the communication device in the wireless communication network utilizes the average power information of the received signal reported by the base station, especially the average power information reported during the period of minimum traffic (such as 2 am to 4 am). Compared with the noise floor of the signal, it is judged whether there is interference of the illegal occupied frequency signal according to the comparison result of the two. In addition, based on the information reported by multiple base stations, the location of the interference source can be initially determined. Therefore, this technical solution is very useful for the operation of wireless communication networks and the maintenance of wireless communication networks. However, when using this technical solution to detect the interference of illegally occupied frequency signals in the existing wireless communication network, there may also be legitimate communication services in the network, so that the detection is easily affected, and in order to reduce the influence, it is necessary to select Statistics at a time when traffic is small are meaningful. Therefore, if the illegal occupation of the frequency signal is during the busy period of the daytime service, the illegal occupation frequency signal is detected. Summary of the invention

The present invention has been made in view of the above problems of the prior art, and an object thereof is to provide a method for detecting an illegally occupied frequency signal in a wireless communication network, which can be applied at any time without being affected by a legitimate communication service.

The method for detecting illegally occupying a frequency signal in a wireless communication network according to the present invention comprises the following steps:

According to the requirement for detecting the illegal occupied frequency signal, the synchronous detection object is determined in the network affected by the same frequency network in the surrounding area;

Keeping the synchronous detection object unassigned to any link use;

In the synchronous detection object, performing signal strength detection on the received signal;

The base station system compares the received signal strength with the signal floor noise. If the difference between the received signal strength and the signal floor noise is greater than a predetermined threshold, it indicates that there is an illegal occupied frequency signal in the network.

Preferably, the step of determining a synchronization detection object comprises: periodically determining one or several consecutive synchronization detection objects.

Preferably, the step of determining the synchronization detection object comprises: randomly determining one or several consecutive synchronization detection objects.

Preferably, when the wireless communication network is a time division multiple access system, the synchronization detection object is a synchronization time slot.

Preferably, when the wireless communication network is a broadband data communication network based on orthogonal frequency division multiplexing/orthogonal frequency division multiplexing access, the synchronous detection object is a synchronous time-frequency resource block.

Preferably, the step of performing signal strength detection on the received signal is performed by the base station system or the terminal system; after the detection is completed, the terminal system reports the detection result of the received signal to the base station system.

Preferably, when the wireless communication network is in a frequency division duplex time division multiple access system or a wideband data communication network based on orthogonal frequency division multiplexing/orthogonal frequency division multiplexing access, for the downlink, The step of performing signal strength detection further includes: the base station system receiving the signal at the transmission frequency point.

By adopting the method of the invention, the interference of the illegal occupied frequency signal in the current wireless communication network can be detected at any time without being affected by the legal communication. Method of the invention It can be applied to a TDD- or FDD-based time division multiple access system to an OFDM/OFDMA-based broadband data communication network. DRAWINGS

Figure 1 is a schematic diagram of communication time slots of a time division duplex (TDD) based time division multiple access system; Figure 2 is a wideband data communication based on Orthogonal Frequency Division Multiplexing (OFDM) / Orthogonal Frequency Division Multiple Access (OFDMA) Schematic diagram of the wireless resources of the network;

3 is a flow chart of detecting an illegal occupation frequency signal according to an embodiment of the present invention; FIG. 4 is a schematic diagram of a typical time division multiple access wireless communication system;

5 is a flow chart of a method for detecting an illegal occupation frequency signal according to another embodiment of the present invention applied to the system of FIG. 4;

6 is a flow chart of a method for detecting an illegal occupation frequency signal according to still another embodiment of the present invention applied to the system of FIG. 4;

7 is a schematic diagram of a broadband data communication network based on OFDM/OFDMA; FIG. 8 is a flow chart of a method for detecting an illegal occupied frequency signal according to still another embodiment of the present invention applied to the network shown in FIG. detailed description

The above objects, features and advantages of the present invention will become more apparent from the detailed description of the appended claims.

Figure 1 is a schematic diagram of communication time slots of a time division multiple access (TDD) based time division multiple access system. The so-called time division multiple access system refers to distinguishing voice and data information of different users through different time slots to avoid interference between different users. For a time division multiple access system adopting the TDD communication mode, the uplink and downlink links share the same frequency resource, and a sufficiently large protection time slot is left between the uplink and downlink time slots to avoid air transmission between the uplink and downlink time slots. Crosstalk caused by delay, as shown in Figure 1. TDD-based time division multiple access wireless networks require strict network synchronization.

For a time division multiple access system adopting the FDD communication mode, the uplink and downlink respectively occupy different frequency points, so that the uplink and downlink links can be avoided by relying on the frequency interval between the uplink and downlink links. Interference.

A broadband data communication network based on OFDM/OFDMA, such as a broadband data communication system based on the 802.16 standard, divides radio resources by subcarriers in the frequency domain, in addition to dividing time slots in the time domain to distinguish users. Thus, the radio resources allocated to each user appear as a region in the plane composed of the time domain and the frequency domain, as shown in Fig. 2, hereinafter referred to as a time-frequency resource block. When the time-frequency resource block contains all sub-carriers, the time-frequency resource block is equivalent to the time-slot, so the time slot is a special case of the time-frequency resource block.

3 is a flow chart of a method of detecting an illegal occupation frequency signal in accordance with one embodiment of the present invention. The detection method of the present invention can be applied to a time division multiple access wireless communication network based on TDD or FDD and a broadband data communication network based on OFDM/OFDMA.

In step 301, the detection object in the network is determined according to the requirement of the interference signal detection. Specifically: determining the detection object in a local area network or the whole network affected by the same frequency network in other areas, synchronizing the time slot in the instant multiple access wireless communication network, or synchronizing the broadband data communication network based on OFDM or OFDMA Time-frequency resource block. The synchronous time slot/synchronous time-frequency resource block means that the start/stop time/start and stop time of the specified time slot/time-frequency resource block and the sub-carrier are the same within the network detection range, and all transceivers in the network range are in the synchronization time. Synchronous detection of illegally occupied frequency signals in the slot/synchronous time-frequency resource block.

The synchronization time slot/synchronous time-frequency resource block size is determined according to the characteristics of the illegal occupied frequency signal and the requirement of detection accuracy. There are various methods for determining a synchronization slot/synchronous time-frequency resource block, including periodically determining one or several consecutive synchronization slot/synchronous time-frequency resource blocks, or randomly determining one or a certain period of time. Several consecutive synchronization time slots/synchronous time-frequency resource blocks, no matter which method is used, as long as the detection of illegally occupied frequency signals is guaranteed to be well covered in both the frequency domain and the time domain, in other words, The periodically determined synchronization time slot/synchronous time-frequency resource block for signal detection can capture most illegal occupied frequency signals and is easy to implement; but for special illegal occupied frequency signals, for example, the interference period is just an integer of the detection period. Times, that During the period, the detection time slot/time-frequency resource block is randomly selected for detection; but the most important thing is that regardless of how the detection slot/time-frequency resource block is selected, it is necessary to ensure that the detection slot/time-frequency resource block has the characteristics of intra-network synchronization.

In step 305, the synchronization slot/synchronous time-frequency resource block determined in step 301 is not allocated any link usage to ensure that there is no service transmission signal in the synchronization slot/synchronous time-frequency resource block, that is, the detected network. There is no base station or terminal transmitting signals. In step 310, the synchronized signal strength detection is performed on the received signal by the determined system, and the signal strength detection may use a power spectrum analysis method, specifically: the base station system performs fast Fourier transform (FFT) processing on the received signal, that is, In the frequency analysis of the broadband signal. Using FFT to process the signal, it is easy to find the presence of narrowband low power interference signals.

In step 315, the base station system compares the strength of the received signal with the signal floor noise. If the difference between the received signal strength and the signal floor noise is greater than a predetermined threshold, it indicates that there is an illegal occupied frequency signal in the network (step 320); No interference was detected that illegally occupied the frequency signal. The test ends and the next test cycle is entered. The predetermined threshold is determined based on the detection accuracy and the noise figure dynamic range of the detecting device itself, and in the present embodiment, the predetermined threshold is set to 3 dB.

Further, after detecting the interference of the illegally occupied frequency signal in the network, the location of the illegally occupied frequency signal source may be initially determined on the network topology according to the detection result of the received signal by the base station.

Preferably, in step 310, the received signal is detected by the terminal system, and then the terminal system reports the detection result of the received signal to the base station system. The signal strength detection method of the terminal system is specifically: the base station system notifies the terminal system of the location of the synchronization time slot/synchronous time-frequency resource block to be detected, and the terminal system performs strength on the received signal in the synchronization time slot/synchronous time-frequency resource block. Detection, if the difference between the received signal strength and the signal floor noise is greater than a predetermined threshold, it indicates that there is illegal occupied frequency signal interference in the network, otherwise it indicates that the illegal occupied frequency signal is not detected. Then, the detection result is transmitted to the base station system through the terminal system. The base station system notifies the terminal system of the location of the synchronization time slot/synchronous time-frequency resource block to be detected, and may use any one of the following methods (but is not limited to this): by configuring a message, or in a synchronization time slot to be detected. /Synchronize The time-frequency resource block is tagged with a special flag, or the location of the fixed sync slot/time-frequency resource block.

For the FDD-based time division multiple access wireless communication network and the OFDM or OFDMA-based broadband data communication network, when detecting whether there is interference of the illegally occupied frequency signal on the downlink, in step 310, the base station system performs transceiving and inversion, that is, The radio frequency point receives the signal, and then the signal strength is detected on the received signal.

It can be seen from the above description that the method according to the embodiment can detect the illegal occupied frequency signal in the wireless communication network, and the FFT processing received signal can easily find the existence of the narrowband low power interference signal.

The implementation of the method of the present invention will be specifically described below by taking a TDD-based time division multiple access wireless communication network as an example.

As shown in FIG. 4, a typical wireless communication network generally includes a base station system BSS and a core network CN. The base station system BSS establishes a communication link with the user terminal in the air to complete the two-way transmission of voice and data information; the service data (voice or data) accesses the public network through the core network CN, such as the PSTN network or the Internet. The core network CN is also responsible for completing functions such as authentication of legitimate users and mobile roaming control. The base station system BSS includes a base transceiver station BTS and a base station controller BSCo. In a time division multiple access system, all BTSs require synchronization, for example, synchronization with a GPS system. Each base station controller BSC has an operation and maintenance interface for connecting the operation and maintenance module OMM. In the network topology diagram, the operation and maintenance module OMM serves as a centralized point of a single base station system BSS, and can establish communication routes with multiple BTSs, and complete functions such as data configuration and device maintenance for the BSS system under the jurisdiction. For a network configured with multiple BSCs, configure the regional operation and maintenance console. The LOMC governs multiple OAMs. In the network topology diagram, the regional operation and maintenance console LOMC serves as a centralized point of multiple base station systems BSS, and can establish communication routes with all BTSs under multiple BSS systems to complete data configuration and control of multiple BSS systems under the jurisdiction. Equipment maintenance and other functions.

If it is a regional network covered by a single base station system BSS, the process shown in Figure 5 can be used to detect the illegal occupied frequency signal.

In step 501, the operation and maintenance module OMM periodically configures one or more synchronization time slots, and the size of the synchronization time slot may be determined according to the characteristics of the illegal occupied frequency signal and the requirements of the detection accuracy. In step 505, the operation and maintenance module OMM transmits configuration information to the base station system BSS through its communication route with the base station system BSS. Then in step 510, the base station system BSS ensures during the scheduling of the resources that no information is transmitted in the configured time slots or times. At step 515, all BTSs in the network perform FFT processing on the received signals in the designated one or more of the time slots to determine the strength of the received signal. Then, it is judged whether there is an illegal occupation frequency signal in the network, which can be executed in the base station system BSS or in the operation and maintenance module OMM. If executed in the base station system BSS, the configuration information transmitted in step 505 further includes a predetermined threshold, such that in step 520, if the difference between the strength of the received signal and the signal floor noise is greater than a predetermined threshold, it indicates that there is illegal occupation. Frequency signal; otherwise, the frequency signal is not illegally occupied, the detection ends, and the next detection cycle is entered. If there is an illegal occupation frequency signal, then in step 525, the base station system BSS transmits the detection result to the operation and maintenance module OMM. If executed in the operation and maintenance module OMM, in step 520, the base station system BSS transmits the determined received signal strength to the operation and maintenance module OMM, and then in step 525, the operation and maintenance module OMM determines the strength of the received signal and Whether the difference between the signal floor noises is greater than a predetermined threshold, and if so, indicates that there is an illegal occupation frequency signal. If there is an illegal occupation frequency signal, step 530 is performed. Finally, in step 530, the location of the illegally occupied frequency signal source is determined by the operation and maintenance module OMM according to the geographical distribution of the interfered base station.

If it is a regional network covered by multiple base station systems BSS, the process shown in Figure 6 can be used to detect the illegal occupied frequency signal.

In step 601, the regional operation and maintenance station LOMC periodically configures one or more synchronization time slots, and the synchronization time slot size is determined according to the characteristics of the interference signal and the detection accuracy. At step 605, the regional operations maintenance station LOMC transmits the configuration information to the respective operation and maintenance modules OMM through its communication route with all the operation and maintenance modules OMM under the jurisdiction. In step 610, the operation and maintenance module OMM transmits configuration information to the corresponding base station system BSS through its communication route with the base station system BSS. At step 615, the base station system BSS ensures during the resource scheduling process that no information is transmitted in the configured time slot or times. Then, in step 620, all BTSs in the network analyze the received signals in the designated time slot or the time slots by using FFT processing to obtain a strong skin of the received signal. Then, to determine whether there is an illegal occupation frequency signal, It can be performed in the base station system BSS or in the regional operation and maintenance station LOMC. If executed in the base station system BSS, the configuration information transmitted in steps 605 and 610 further includes a predetermined threshold, such that in step 625, if the difference between the strength of the received signal and the signal floor noise is greater than a predetermined threshold, then the presence is indicated Illegal occupation of the frequency signal; otherwise, the frequency signal is not illegally occupied, the detection ends, and the next detection cycle is entered. If there is an illegal occupation frequency signal in the network, in step 630, the base station system BSS transmits the detection result to the corresponding operation and maintenance module OMM, and then transmits it to the regional operation and maintenance station LOMC. If executed in the regional operation and maintenance station LOMC, in step 625, the base station system BSS transmits the determined received signal strength to the corresponding operation and maintenance module OMM, and then to the regional operation and maintenance station LOMC, in step 630, It is judged by the regional operation and maintenance station LOMC whether the difference between the strength of the received signal and the signal noise of the signal is greater than a predetermined threshold, and if so, it indicates that there is an illegal occupation frequency signal. If there is an illegal occupation frequency signal, step 635 is performed. In step 635, the regional operations maintenance station LOMC may determine the location of the illegally occupied frequency signal source based on the geographical distribution of the interfered base station.

Figure 7 shows a schematic diagram of an OFDM/OFDMA based broadband data communication network into a Next Generation Communication Network (NGN). The OFDM/OFDMA-based broadband data communication network usually includes an OFDM/OFDMA base station subsystem BSS, an operation and maintenance server (OMM), and an access gateway (AGW), wherein the base station subsystem BSS is connected to the access gateway AGW. The gateway AGW, NGN and the operation and maintenance server OMM are connected through the Internet. The base station subsystem BSS establishes a communication link with the user terminal in the air to complete the two-way transmission of voice and data information. The service data (voice or data) is connected through the access gateway AGW. Entering the Internet, and the next-generation communication network NGN is responsible for completing authentication and mobile roaming control for legitimate users. The base station subsystem BSS includes a base transceiver station BTS and a base station controller BSC. Each base station controller BSC has an operation and maintenance interface, which can be directly connected to the operation and maintenance server OMM, or can be connected to the operation and maintenance server OMM through the Internet. In the network topology, the OMM can establish communication routes with multiple BTSs to complete data configuration and device maintenance for the BSS subsystems under its jurisdiction.

For the area network covered by the base station subsystem BSS, the flow pair shown in FIG. 8 can be used. Illegal occupation of frequency signals for detection. In step 801, the operation and maintenance server OMM periodically configures one or more synchronous time-frequency resource blocks, and the synchronous time-frequency resource block size can be determined according to the characteristics of the illegal occupied frequency signal and the detection accuracy. In step 803, the operation maintainer OMM sends the configuration information to the access gateway AGW, and in step 805, the access gateway AGW performs address mapping on the configuration information and transmits the configuration information to the base station subsystem BSS. Then in step 810, the base station subsystem BSS ensures that no information is transmitted in the configured time or frequency resource blocks during the scheduling of the resources. In step 815, all BTSs in the network perform FFT processing on the received signals in the designated time or frequency resource block to determine the spectral strength of the received signal. Then, it is judged whether or not there is an illegal occupation frequency signal, which can be executed in the base station subsystem BSS or in the operation maintainer OMM. If executed in the base station subsystem BSS, the configuration information transmitted in steps 803 and 805 further includes a predetermined threshold, such that in step 820, if the difference between the strength of the received signal and the signal floor noise is greater than a predetermined threshold, then There is an illegal occupation frequency signal; otherwise, the frequency signal is not illegally occupied, the detection ends, ^A next detection cycle. If there is an illegal occupation frequency signal, then in step 825, the base station subsystem BSS transmits the detection result to the access gateway AGW, and then the access gateway AGW performs address mapping on the detection result and transmits it to the operation maintainer OMM. If executed in the operation maintainer OMM, in step 820, the base station subsystem BSS transmits the determined received signal strength to the access gateway AGW, and the access gateway AGW performs address mapping on the signal detection strength information, and then transmits the information to the access gateway AGW. The operation and maintenance server OMM is operated, and then in step 825, it is judged by the operation maintainer OMM whether the difference between the received signal strength and the signal floor noise is greater than a predetermined threshold, and if so, it indicates that there is an illegal occupation frequency signal. If there is an illegal occupation frequency signal, step 830 is performed. In step 830, the location of the illegally occupied frequency signal source is then determined by the operation and maintenance server OMM based on the geographical distribution of the interfered base station. Industrial applicability

The method of the invention can be applied to a wireless communication network, in particular, a time division multiple access wireless communication network based on TDD/FDD and a broadband data communication network based on OFDM/OFDMA, for detecting whether there is an illegal occupation frequency signal in the uplink and downlink.

Claims

Claim

A method for detecting an illegally occupied frequency signal in a wireless communication network, comprising the steps of:

Keeping the synchronous detection object unassigned to any link use;

The method according to claim 1, wherein the determining the synchronization detection object comprises: periodically determining one or several consecutive synchronization detection objects.

The method according to claim 1, wherein the determining the synchronization detection object comprises: randomly determining one or several consecutive synchronization detection objects.

The method according to claim 1, wherein when the wireless communication network is a time division multiple access system, the synchronization detection object is a synchronization time slot.

The method according to claim 1, wherein when the wireless communication network is a broadband data communication network based on orthogonal frequency division multiplexing/orthogonal frequency division multiplexing access, the synchronous detection object It is a synchronous time-frequency resource block.

The method according to claim 4 or 5, wherein the step of performing signal strength detection on the received signal is performed by a base station system or a terminal system; and the terminal system detects the received signal after the detection is completed. The result is reported to the base station system.

The method according to claim 6, wherein the step of performing signal strength detection uses a power spectrum analysis method to perform intensity detection on the received signal to obtain a frequency strength of the received signal.

The method according to claim 7, wherein the power transmission analysis method is a fast Fourier transform method

9. The method of claim 8, wherein when the wireless communication network is In the broadband data communication network, for the downlink, the step of performing signal strength detection further includes: the base station system receiving the signal at the transmission frequency point.

The method according to claim 8, wherein the method further comprises: determining a location of the illegal occupied frequency signal source on the base station distribution topology according to the detection result of the base station system.