CN108668280A - A cell access method and device for preventing false base stations - Google Patents

Abstract

The invention discloses a cell access method for preventing false base stations, comprising: after a mobile station triggers cell selection or cell reselection, acquires a broadcast control channel BCCH carrier to be added to the cell; decodes the BCCH carrier to obtain the BCCH carrier BCCH information, determine the cell access feature information of the cell to be added according to the BCCH information; judge whether the cell access feature information meets the preset conditions, and if so, determine that the cell to be added is a non-pseudo base station For the covered cell, the cell to be added is accessed as the cell to be camped on. The invention also discloses a cell access device for preventing false base stations.

Description

A cell access method and device for preventing false base stations

technical field

The invention relates to network security technology, in particular to a cell access method and device for preventing false base stations.

Background technique

In order to send more spam text messages and fraudulent text messages, malicious people place fake base stations in densely populated areas, set the frequency points to be different from those of normal cells with good signals around them, set higher power, and configure the LAC value It is a different LAC value from the current location area of the mobile station to attract more mobile stations. After triggering the mobile phone to update its location, the fake base station pushes spam messages to the mobile phone, seriously harassing users, interfering with communication, and endangering society, which has aroused widespread concern in the society. Existing monitoring programs fall into the following categories:

Method 1. A signaling monitoring solution on the operator's network side. Specifically, false base stations will cause the number of mobile phone location updates within a certain range to be abnormal. Based on statistical analysis of signaling, operators can monitor false base stations and the approximate area where they appear.

Method 2. Mobile phone software (APP) terminal side monitoring solution. To be specific: the mobile APP is based on the user's marking of the received text messages, and a large number of mobile phones in the same area receive the same spam text messages for big data analysis, and can detect pseudo base stations.

Method 3. On-site frequency analysis and monitoring scheme. Specifically: scan wireless frequency points in key areas, analyze the abnormal location area code (LAC, location area code) value of the cell, and also monitor the pseudo base stations that appear nearby.

Method 4, mobile phone chip abnormality protection scheme. Specifically, an abnormal parameter feature library is established for broadcast parameters such as pseudo-base station control channel description parameters, cell selection parameters, cell identifiers, and location area identifiers. If the current cell matches, it is determined to be a pseudo-base station, and the mobile phone refuses to camp in the cell.

The above monitoring schemes all have some deficiencies, and there are some misjudgments or failures in the monitoring process, resulting in the problem of false base stations that has not been effectively resolved. Specifically, the above monitoring methods have the following disadvantages respectively:

Method 1. The signaling monitoring method on the operator’s network side is post-event monitoring, which has a serious lack of timeliness and cannot obtain the precise location of the fake base station. Since the fake base station has the characteristics of strong mobility in order to avoid attack, it is more difficult to locate and capture it accurately.

Method 2. The mobile APP terminal side monitoring method requires a large number of users to install terminal software, which affects user experience; the mobile APP makes judgments based on events and SMS characteristics, and there are misjudgments; mobile APP monitoring belongs to post-event monitoring. Short message.

Method 3. On-site frequency analysis and monitoring methods can only find obviously abnormal cells with LAC values of 0 and 65535. Usually, in order to evade attacks, some pseudo base stations will set the LAC to the LAC value used by the normal operator network, so that the on-site monitoring solution will be invalid.

Method 4. The mobile phone chip exception protection method is to establish an abnormal feature library based on broadcast parameters to match and find fake base stations. It is very easy to be bypassed by fake base stations by simulating normal base station parameters, and it may also cause mobile phones to end up with no cells to access.

Contents of the invention

In view of this, the embodiments of the present invention expect to provide a cell access method and device for preventing fake base stations, which can judge whether a base station is a normal base station during cell selection and cell reselection, and effectively prevent mobile phones from accessing fake base stations from the source.

In order to achieve the above object, technical solution of the present invention is achieved in that way:

An embodiment of the present invention provides a cell access method for preventing fake base stations, the method comprising:

After the mobile station triggers cell selection or cell reselection, it acquires the broadcast control channel BCCH carrier to join the cell;

Decoding the BCCH carrier to obtain BCCH information carried by the BCCH carrier, and determining cell access feature information of the cell to be joined according to the BCCH information;

Judging whether the cell access characteristic information satisfies a preset condition, and if so, determining that the cell to be added is a cell not covered by a pseudo base station, and accessing the cell to be added as a resident cell.

In the above solution, the judging whether the cell access feature information meets the preset conditions includes:

Analyzing the cell access feature information to obtain the minimum reception level allowed by the mobile station, the maximum power level of the control channel, the cell reselection offset, the cell reselection lag and/or the location area code LAC;

When the minimum reception level allowed by the mobile station, the maximum power level of the control channel, the cell reselection offset, the cell reselection hysteresis and/or the LAC meet a preset threshold, then The preset conditions are met.

In the above solution, when the minimum reception level allowed by the mobile station, the maximum power level of the control channel, the cell reselection offset, the cell reselection hysteresis and/or the LAC meet the preset threshold, the preset conditions are met, including at least one of the following situations:

If the minimum reception level allowed by the mobile station to access is less than a first threshold, the preset condition is met;

If the maximum power level of the control channel is greater than a second threshold, the preset condition is met;

If the cell reselection offset is greater than a third threshold, the preset condition is met;

If the cell reselection lag is greater than a fourth threshold, the preset condition is met;

If the LAC is not a set value, the preset condition is met.

In the above solution, the cell access feature information further includes: system information broadcast by the base station;

The judging whether the cell access characteristic information satisfies a preset condition also includes:

The system message broadcast by the base station is analyzed, and if the Internet access capability information and neighboring cell information are obtained through analysis, the preset condition is met.

In the above scheme, before the acquisition of the broadcast control channel BCCH carrier of the cell to be added, the method also includes:

Judging whether the mobile station stores a BCCH carrier, if the BCCH carrier is stored, then obtaining the stored BCCH carrier as the BCCH carrier of the cell to be added;

If the BCCH carrier is not stored, the mobile station tunes to the carrier with the highest receiving level, judges whether the carrier is a BCCH carrier, and if it is a BCCH carrier, obtains the BCCH carrier as the BCCH carrier of the cell to be added.

In the above solution, before determining that the cell to be joined is a cell not covered by a pseudo base station, the method further includes:

Analyzing the cell access characteristic information to obtain the network type, cell status and/or path loss criterion parameters of the cell to be added;

When the network type belongs to the public land mobile network PLMN, the cell state is not disabled, and/or the path loss criterion parameter is greater than 0, it is determined that the cell to be joined is a cell not covered by a pseudo base station.

In the above scheme, before the acquisition of the broadcast control channel BCCH carrier of the cell to be added, the method also includes:

Judging whether the cell where the mobile station resides satisfies the cell reselection condition, if so, reselecting the cell satisfying the preset condition from the broadcast control channel configuration BA list as the cell to be added, and obtaining the BCCH carrier of the cell to be added .

An embodiment of the present invention provides a cell access device for preventing fake base stations, the device includes: a first processing module, a second processing module, and a third processing module; wherein,

The first processing module is configured to acquire a broadcast control channel BCCH carrier to be added to a cell after cell selection or cell reselection is triggered;

The second processing module is configured to decode the BCCH carrier to obtain BCCH information carried by the BCCH carrier, and determine the cell access characteristic information of the cell to be joined according to the BCCH information;

The third processing module is configured to judge whether the cell access feature information meets a preset condition, and if so, determine that the cell to be added is a cell not covered by a pseudo base station, and use the cell to be added as a resident The community is accessed.

In the above solution, the third processing module is specifically configured to analyze the cell access feature information to obtain the minimum reception level allowed by the mobile station, the maximum power level of the control channel, the cell reselection offset, Cell reselection hysteresis and/or location area code LAC;

When the minimum reception level allowed by the mobile station, the maximum power level of the control channel, the cell reselection offset, the cell reselection hysteresis and/or the LAC meet a preset threshold, then The preset conditions are met.

In the above solution, when the minimum reception level allowed by the mobile station, the maximum power level of the control channel, the cell reselection offset, the cell reselection hysteresis and/or the LAC meet the preset threshold, the preset conditions are met, including at least one of the following situations:

If the minimum reception level allowed by the mobile station to access is less than a first threshold, the preset condition is met;

If the maximum power level of the control channel is greater than a second threshold, the preset condition is met;

If the cell reselection offset is greater than a third threshold, the preset condition is met;

If the cell reselection lag is greater than a fourth threshold, the preset condition is met;

If the LAC is not a set value, the preset condition is met.

In the above solution, the cell access feature information further includes: system information broadcast by the base station;

The third processing module is further configured to analyze the system information broadcast by the base station, and if the Internet access capability information and neighboring cell information are obtained through analysis, the preset condition is met.

In the above solution, the first processing module is also used to judge whether the mobile station stores a BCCH carrier, and if the BCCH carrier is stored, obtain the stored BCCH carrier as the BCCH carrier of the cell to be added;

If the BCCH carrier is not stored, the mobile station tunes to the carrier with the highest receiving level, judges whether the carrier is a BCCH carrier, and if it is a BCCH carrier, obtains the BCCH carrier as the BCCH carrier of the cell to be added.

In the above solution, the third processing module is further configured to analyze the cell access feature information to obtain the network type, cell status and/or path loss criterion parameters of the cell to be added;

When the network type belongs to the public land mobile network PLMN, the cell state is not disabled, and/or the path loss criterion parameter is greater than 0, it is determined that the cell to be joined is a cell not covered by a pseudo base station.

In the above solution, the first processing module is also used to judge whether the cell where the mobile station resides satisfies the cell reselection condition, and if so, reselect the cell that meets the preset condition from the broadcast control channel configuration BA list As a cell to be joined, the BCCH carrier of the cell to be joined is obtained.

In the cell access method and device for preventing fake base stations provided by the embodiments of the present invention, after the mobile station triggers cell selection or cell reselection, it acquires the broadcast control channel BCCH carrier to be added to the cell; decodes the BCCH carrier to obtain the The BCCH information carried by the BCCH carrier determines the cell access feature information of the cell to be added according to the BCCH information; judges whether the cell access feature information satisfies a preset condition, and if so, determines that the cell to be added is For a cell that is not covered by the pseudo base station, the cell to be added is accessed as a resident cell. The method and device provided by the embodiments of the present invention prevent false base stations without changing the standard communication process and without affecting user experience and usage habits; no longer actively identify false base stations, and avoid misjudgment in the process of identifying false base stations; The cell access feature information of the cell to be added is used to judge whether the base station to be added is a normal base station, so as to avoid the situation that the pseudo base station simulates the normal base station parameters and is difficult to detect.

Description of drawings

FIG. 1 is a schematic flowchart of a cell access method for preventing fake base stations provided by an embodiment of the present invention;

FIG. 2 is a schematic flowchart of a general cell selection method provided by an embodiment of the present invention;

FIG. 3 is a schematic flow diagram of a cell access method 1 for preventing fake base stations provided by an embodiment of the present invention;

FIG. 4 is a schematic flowchart of a second cell access method for preventing fake base stations provided by an embodiment of the present invention;

FIG. 5 is a schematic flowchart of a third cell access method for preventing fake base stations provided by an embodiment of the present invention;

FIG. 6 is a schematic structural diagram of a device for preventing false base stations from accessing a cell according to an embodiment of the present invention.

Detailed ways

In the embodiment of the present invention, after triggering cell selection or cell reselection, the mobile station obtains the broadcast control channel BCCH carrier to join the cell; decodes the BCCH carrier to obtain the BCCH information carried by the BCCH carrier, and determines the BCCH information according to the BCCH information. Describe the cell access feature information of the cell to be added; judge whether the cell access feature information satisfies a preset condition, and if so, determine that the cell to be added is a cell not covered by a pseudo base station, and use the cell to be added as The resident cell shall be accessed.

Before the present invention is further described in detail in conjunction with the embodiments, the pseudo base station and the normal base station are first described as follows.

According to the specifications of the 3rd Generation Partnership Project (3GPP, 3rd Generation Partnership Project), when the mobile station performs cell selection and cell reselection, it mainly depends on the average receiving level of the mobile station, the minimum receiving level allowed by the mobile station, and the control channel Parameters such as maximum power level, maximum transmit power level of mobile station, cell reselection bias, temporary bias, penalty time, etc. do not consider whether the cell is a normal cell or not, and the parameters of some abnormal cells may also meet the requirements of cell selection and cell reselection. The mobile station accesses upon request.

Since the pseudo base station can simulate the parameters involved in cell selection and cell reselection, it is difficult to judge whether the selected cell is a cell covered by the pseudo base station based on the above parameters, which makes it difficult for the abnormal protection scheme of the mobile station chip to have a good effect.

The broadcast parameters of the normal base station are optimized and reasonable, with complete business functions and perfect networking configuration. However, due to concerns such as cost, system simplification, performance improvement, and attracting more mobile stations, some of the services of the pseudo base station have not been realized. Network configuration is also problematic.

It is difficult to find pseudo base stations through abnormal broadcast parameter characteristics, but abnormal base stations that do not match the characteristics of normal base stations can be found through cell access characteristic parameters, service function characteristics, and networking configuration characteristics involved in cell selection and cell reselection.

A normal base station has the following typical characteristics:

(1) Cell access feature parameters refer to some necessary parameters involved in cell selection and cell reselection by the mobile station, including:

The minimum receiving level (RXLEV_ACCESS_MIN), the maximum power level of the control channel (MS_TXPWR_MAX_CCH), the cell reselection offset (CRO, Cell Reselect Offset), the temporary offset (TO, Temporary Offset), the penalty time ( PT, Penality Time), cell reselection hysteresis (CRH, CellReselection Hysteresis), LAC.

The parameters configured by the pseudo-base station are usually different from the relevant parameters of the operator's network, but the pseudo-base station can simulate the parameters set by the normal base station to avoid the mechanism of parameter-based monitoring. For example, in order to push a short message to a mobile phone, the pseudo base station needs to be configured with a different LAC value from the cell where the current mobile station resides. In many default cases, the LAC value of the pseudo base station is usually 0, 65535 and other abnormal values.

Through the analysis and statistics of a large number of actual networks and pseudo base stations, it is found that the typical values of cell access characteristic parameters such as cell selection and cell reselection for normal base stations and pseudo base stations are shown in Table 1:

pseudo base station normal base station RXLEV_ACCESS_MIN 0 -98 MS_TXPWR_MAX_CCH 0 33 CROs 0 55 TO 0 0 PT 0 0 CRH 3 10 LAC 0, 65535 Take the value according to the needs of the network

Table 1 Typical values of parameters related to pseudo base stations and normal base stations

It can be seen that the values of the cell access characteristic parameters of the normal base station and the pseudo base station are quite different when performing cell selection and cell reselection, and the parameter value range characteristics of the normal base station cell are relatively obvious. A cell covered by a normal base station.

(2) Features of business functions

Under the current circumstances, operators have good network coverage and complete network functions. Every normal base station will have voice and data functions, and can provide users with services such as telephone calls, text messages, and Internet access.

When a normal base station supports Internet access capability, it will broadcast a system message including Internet access capability information (PS Indicator). However, most of the pseudo base stations do not support Internet access capabilities due to functional simplification and efficiency, and only support SMS functions.

Therefore, whether the system message broadcast by the base station includes Internet access capability information can determine whether it is a normal base station, and a base station that does not include Internet access capability information can be regarded as an abnormal base station.

(3) Network configuration features

A normal base station is only a part of the network, and a large number of base stations form a network through networking configuration. Many base stations are connected due to cell handover and cell reselection, that is, cells form a cellular network through neighbor cell relationships. In order to maintain the cellular network and realize functions such as cell handover and cell reselection, the base station needs to broadcast system messages containing the information of neighboring cells when networking.

The pseudo base station is an independent device that does not need to interact with other base stations, does not configure neighbor cell information, and does not broadcast neighbor cell relations to the outside world. The broadcast system information does not include neighbor cell information.

Therefore, whether the system message broadcast by the base station includes neighboring cell information can determine whether it is a normal base station, and a base station that does not include neighboring cell information can be regarded as an abnormal base station.

It should be noted that: For the current pseudo-base station, it may have the function of configuring and changing cell access characteristic parameters such as cell selection and cell reselection, but it does not have functions such as business function characteristics and networking configuration characteristics, and cannot be configured through the system. to broadcast system messages containing the above features.

The present invention will be described in further detail below in conjunction with the examples.

FIG. 1 is a schematic flow diagram of a cell access method for preventing fake base stations provided by an embodiment of the present invention; as shown in FIG. 1 , the method includes:

Step 101, after a mobile station (MS, mobile station) triggers cell selection or cell reselection, it acquires a broadcast control channel (BCCH, Broadcast Control Channel) carrier to be added to the cell;

Specifically, the mobile station is a terminal device used by a mobile user that can establish a two-way wireless telephone circuit with a base station and conduct a call.

The mobile station may include a vehicle type, a portable type, and a handheld type; for example, the handheld type may include: a mobile phone, a communication terminal, a smart terminal, and other devices.

Step 102, the mobile station decodes the BCCH carrier to obtain BCCH information carried by the BCCH carrier, and determines the cell access characteristic information of the cell to be joined according to the BCCH information;

Specifically, the mobile station decodes the BCCH carrier to obtain BCCH information carried by the BCCH carrier, including:

The mobile station decodes a synchronization channel (SCH, Synchronization Channel) to synchronize with the BCCH carrier, and obtains BCCH information carried by the BCCH carrier.

Step 103, the mobile station judges whether the access characteristic information of the cell satisfies the preset condition, and if so, determines that the cell to be added is a cell not covered by a pseudo base station, and accesses the cell to be added as a resident cell .

Specifically, the cell access characteristic information includes: the minimum receiving level (RXLEV_ACCESS_MIN) that the mobile station is allowed to access, the maximum power level of the control channel (MS_TXPWR_MAX_CCH), the cell reselection offset (CRO, CellReselect Offset), the cell Reselection hysteresis (CRH, Cell Reselection Hysteresis) and location area code (LAC, location area code).

Specifically, the judging whether the cell access feature information satisfies a preset condition includes:

Analyzing the cell access feature information to obtain the minimum reception level allowed by the mobile station, the maximum power level of the control channel, the cell reselection offset, the cell reselection lag and/or the location area code LAC;

When the minimum reception level allowed by the mobile station, the maximum power level of the control channel, the cell reselection offset, the cell reselection hysteresis and/or the LAC meet a preset threshold, then The preset conditions are met.

Here, when the minimum reception level allowed by the mobile station, the maximum power level of the control channel, the cell reselection offset, the cell reselection hysteresis and/or the LAC meet a preset threshold , the preset conditions are met, including at least one of the following conditions:

If the minimum reception level allowed by the mobile station to access is less than a first threshold, the preset condition is met;

If the maximum power level of the control channel is greater than a second threshold, the preset condition is met;

If the cell reselection offset is greater than a third threshold, the preset condition is met;

If the cell reselection lag is greater than a fourth threshold, the preset condition is met;

If the LAC is not a set value, the preset condition is met.

Here, the first threshold may be -49, the second threshold may be 16, the third threshold may be 27, the fourth threshold may be 6, and the non-set value is not 0, 65535 value.

The method provided by the embodiment of the present invention can be applied in the process of cell selection or cell reselection, wherein the cell selection includes two cases: the mobile station stores the BCCH carrier and the mobile station does not store the BCCH carrier.

Specifically, before the mobile station acquires the BCCH carrier of the cell to be joined, the method further includes:

Judging whether the mobile station stores a BCCH carrier, if the BCCH carrier is stored, then obtaining the stored BCCH carrier as the BCCH carrier of the cell to be added;

If the BCCH carrier is not stored, the mobile station tunes to the carrier with the highest receiving level, judges whether the carrier is a BCCH carrier, and if it is a BCCH carrier, obtains the BCCH carrier as the BCCH carrier of the cell to be added.

The decoding the BCCH carrier to obtain the BCCH information carried by the BCCH carrier includes:

The mobile station decodes the SCH channel and synchronizes with the BCCH carrier to obtain BCCH information carried by the BCCH carrier.

Specifically, before determining that the cell to be joined is a cell not covered by a pseudo base station, the method further includes:

Analyzing the cell access characteristic information to obtain the network type, cell status and/or path loss criterion parameters of the cell to be added;

When the network type belongs to the public land mobile network PLMN, the cell state is not disabled, and/or the path loss criterion parameter is greater than 0, it is determined that the cell to be joined is a cell not covered by a pseudo base station.

The above is the process of cell selection by the mobile station to prevent false base stations.

Specifically, before the mobile station acquires the BCCH carrier of the cell to be joined, the method further includes:

Judging whether the cell where the mobile station resides satisfies the cell reselection condition, if so, reselecting the cell that meets the preset condition from the broadcast control channel configuration (BA, BCCH allocation) list as the cell to be added, and obtaining the cell to be added Join the BCCH carrier of the cell.

Specifically, the judging whether the cell where the mobile station resides meets the cell reselection condition includes:

The mobile station obtains the path loss criterion parameter (C1), downlink signaling link failure counter (DSC), cell state, cell reselection parameter (C2), cell reselection hysteresis parameter, etc. of the cell currently camped on;

If it is determined that the cell currently camped on satisfies any of the following conditions, then it is determined that the mobile station meets the cell reselection condition:

1) The wireless path loss of the cell where the cell is currently camped on is too large, that is, the path loss criterion parameter (C1)<=0 within 5 consecutive seconds;

2), the downlink failure of the cell currently camped on, that is, the downlink signaling link failure counter (DSC)<=0;

3), the current residential area is prohibited;

4) There is a better cell in the same location area than the current cell, that is, the C2 of the non-serving cell exceeds the C2 of the serving cell for 5 consecutive seconds, or, use the cell reselection hysteresis parameter (CRH) to determine the selected cell There is a better cell in another location area in the network;

5) The number of times of random access reaches the maximum number of retries broadcast on the BCCH, but still fails to successfully access the cell where it is currently camping.

Among them, C2=C1+CRO-TO*H(PT-T), when PT<>31;

C2=C1-CRO, when PT=31;

C1=(RXLEV-ACCMIN)-MAX(CCHPWR-P,0);

The CRO indicates the cell reselection offset (Cell Reselect Offset), the TO indicates the time offset (Temporary Offset), the PT indicates the penalty time, and the T indicates that the adjacent cell enters the first six cells of the mobile station measurement report The time length of H(X)=0(X<0) or 1(X≥0), the RXLEV indicates the received signal strength, the ACCMIN indicates the minimum access level, and the CCHPWR indicates that the mobile station receives The maximum transmission power allowed when entering the cell, and the P represents the maximum transmission power of the mobile station.

Specifically, the cells that meet the preset conditions may include: other cells in the BA list that have stronger carriers than the cell currently camped on, or cells that meet other conditions.

It should be noted that after the mobile station camps in the cell, it continuously monitors the BCCH carriers of all adjacent cells and the serving cell to determine whether there is a more suitable cell to access. In order to monitor changes in cell parameters, read the system information published on the BCCH carrier at least every 30 seconds, and at least every five minutes, try to synchronize the six other strongest carrier frequencies in the BA list, and read the BCCH related to cell reselection information.

The above is the process of cell reselection by the mobile station to prevent false base stations.

Figure 2 is a schematic flow diagram of a general cell selection method provided by an embodiment of the present invention; as shown in Figure 2, the method includes:

Step 201, the mobile station searches for 124 radio frequency (RF, Radio Frequency) channels, and calculates the average level (AV_RXLEV) of each RF channel, and this process takes about 3-5 seconds;

Step 202, the mobile station averages the received signal strengths of the 5 channels from each carrier, as the level of the carrier received by the mobile station, and the mobile station tunes to the carrier with the highest level as the received carrier;

Step 203, judge whether the received carrier is a BCCH carrier by searching for a frequency correction channel (FCCH, Frequency Correction Channel) burst (burst), if yes, then enter step 204, otherwise tune to the next strong carrier as the received carrier , and determine whether it is a BCCH carrier;

Step 204, the mobile station decodes a synchronization channel (SCH, Synchronization Channel) to synchronize with the BCCH carrier, and obtains BCCH information carried by the BCCH carrier;

Step 205, determine the network type of the cell to be added according to the BCCH information, judge whether the cell to be added is a PLMN, if so, enter step 206, otherwise enter step 209;

Step 206, determine the cell status of the cell to be added according to the BCCH information, and judge whether the cell to be added is disabled, if not disabled, then enter step 207, otherwise enter step 209;

Step 207, determine the C1 of the cell to be added according to the BCCH information, and judge whether the C1 of the cell to be added is greater than 0, if it is greater than 0, enter step 208, otherwise enter step 209;

Step 208, taking the cell to be joined as the resident cell, and accessing the resident cell;

Step 209 , tune to an untried sub-strong carrier, and return to step 203 .

Normally, two different methods are used for cell selection: storage cell list selection method and general cell selection method. The method of storing the cell list includes: choosing to use a stored BA list for quick selection; when there is no BA list to use, the above-mentioned general cell selection method is selected.

Fig. 3 is a schematic flowchart of a cell access method 1 for preventing false base stations provided by an embodiment of the present invention; as shown in Fig. 3 , the method includes:

Step 301, when the mobile station does not store the BCCH carrier, search 124 RF channels, and calculate the average level of each RF channel, and this process takes about 3-5 seconds;

Step 302, the mobile station averages the received signal strengths of the 5 channels from each carrier, as the level of the carrier received by the mobile station, and the mobile station tunes to the carrier with the highest level as the received carrier;

Step 303, judge whether the received carrier is a BCCH carrier by searching for the FCCH burst, if yes, then enter step 304, otherwise, tune to the next strong carrier as the received carrier and judge whether it is a BCCH carrier again;

Step 304, the mobile station decodes the SCH channel and synchronizes with the BCCH carrier, and obtains the BCCH information carried by the BCCH carrier; determines the cell access characteristic information of the cell to be added corresponding to the BCCH information according to the BCCH information;

Specifically, the cell access feature information includes: cell access feature parameters and system messages broadcast by the base station;

The cell access characteristic parameters include: the minimum reception level allowed by the mobile station, the maximum power level of the control channel, the cell reselection offset, the cell reselection hysteresis and the LAC;

Step 305, judging whether the cell access characteristic parameter of the cell to be added is normal, if normal, enter step 306, otherwise enter step 312;

Here, judging whether the cell access feature parameters of the cell to be joined are normal includes:

When the minimum reception level allowed by the mobile station is less than the first threshold, the maximum power level of the control channel is greater than the second threshold, the cell reselection offset is greater than the third threshold, and the cell reselection lag is greater than When the fourth threshold and/or the LAC is a non-set value, the cell access characteristic parameter of the cell to be added is normal.

Step 306, judging whether the service function characteristics of the cell to be added are normal, if normal, enter step 307, otherwise enter step 312;

Here, it is judged whether the service function characteristics of the cell to be added are normal, including:

Analyzing the system message broadcast by the base station, if the Internet access capability information is obtained from the system message broadcast by the base station, it is determined that the service function of the cell to be added is normal.

Step 307, judging whether the network configuration feature of the cell to be added is normal, if normal, enter step 308, otherwise enter step 312;

Here, it is judged whether the networking configuration features of the cell to be joined are normal, including:

Analyzing the system message broadcast by the base station, if the information of the neighboring cell is obtained from the system message broadcast by the base station, then it is determined that the network configuration feature of the cell to be added is normal.

Step 308, determine the network type of the cell to be added according to the BCCH information, and judge whether the cell to be added is a PLMN, if yes, enter step 309, otherwise enter step 312;

Step 309, determine the cell status of the cell to be added according to the BCCH information, and determine whether the cell to be added is disabled, if not disabled, then enter step 310, otherwise enter step 312;

Step 310, determine the C1 of the cell to be added according to the BCCH information, and judge whether the C1 of the cell to be added is greater than 0, if it is greater than 0, enter step 311, otherwise enter step 312;

Step 311, use the cell to be joined as the resident cell, access the resident cell, and end the process;

Step 312, judging whether all carriers are tried, if not all carriers are tried, then enter step 313, if all have been tried, then enter step 314;

Step 313, tuning to an untried sub-strong carrier, and returning to step 303;

Step 314, the mobile station takes the strongest carrier cell as the camping cell, and accesses the camping cell.

Here, if there is still no suitable cell to camp on after searching all the frequency bands through the above steps, the mobile station will select the existing cell with the strongest carrier to access, and restart the search process every once in a while to find a suitable cell. Residential area.

FIG. 4 is a schematic flow diagram of a second cell access method for preventing fake base stations provided by an embodiment of the present invention; as shown in FIG. 4 , the method includes:

Step 401, when the mobile station stores a BCCH carrier, the mobile station searches for the stored carrier;

Step 402, judge whether the received carrier is a BCCH carrier by searching for the FCCH burst, if yes, then enter step 403, otherwise, tune to the second-strongest carrier as the received carrier and judge whether it is a BCCH carrier again;

Step 403, the mobile station decodes the SCH channel and synchronizes with the BCCH carrier to obtain the BCCH information carried by the BCCH carrier; according to the BCCH information, determine the cell access characteristic information of the cell to be added corresponding to the BCCH information;

The cell access feature information includes: cell access feature parameters and system messages broadcast by the base station;

The cell access characteristic parameters include: the minimum reception level allowed by the mobile station, the maximum power level of the control channel, the cell reselection offset, the cell reselection hysteresis and the LAC;

Step 404, judging whether the cell access characteristic parameter of the cell to be added is normal, if normal, enter step 405, otherwise enter step 411;

Here, it is the same as step 305 in the method shown in FIG. 3 , and will not be repeated here.

Step 405, judging whether the service function characteristics of the cell to be added are normal, if normal, enter step 406, otherwise enter step 411;

Here, it is the same as step 306 in the method shown in FIG. 3 , and will not be repeated here.

Step 406, judging whether the network configuration feature of the cell to be added is normal, if normal, enter step 407, otherwise enter step 411;

Here, it is the same as step 307 in the method shown in FIG. 3 and will not be repeated here.

Step 407, determine the network type of the cell to be added according to the BCCH information, and determine whether the cell to be added is a PLMN, if yes, enter step 408, otherwise enter step 411;

Step 408, determine the cell state of the cell to be added according to the BCCH information, and determine whether the cell to be added is disabled, if not disabled, then enter step 409, otherwise enter step 411;

Step 409, determine the C1 of the cell to be added according to the BCCH information, and judge whether the C1 of the cell to be added is greater than 0, if it is greater than 0, enter step 410, otherwise enter step 411;

Step 410, taking the cell to be joined as the cell to reside on, accessing the cell to reside on, and ending the procedure;

Step 411, adjust the cell to be added to the bottom of the BA list, and mark it as attempted processing;

Step 412, judging whether all the cells in the BA list have been tried, if not all tried, enter step 413, and if all have been tried, then enter step 414;

Step 413, tune to the next cell in the BA list as a new cell to be added, return to step 402;

Step 414, the mobile station performs a process of cell selection without storing BCCH, that is, uses the method shown in FIG. 3 to select a cell.

Here, if the mobile station finds a cell that does not meet the characteristics of a normal base station, it adjusts the priority of this cell to the end of the BA list, and sequentially searches other BCCH carriers in the BA list until an available cell is determined. If no available cell is found, the process of selecting a cell without a stored BA list for the mobile station to prevent access to a false base station is performed.

FIG. 5 is a schematic flow diagram of a third cell access method for preventing fake base stations provided by an embodiment of the present invention; as shown in FIG. 5 , the method includes:

Step 501, during the cell reselection process, the mobile station tunes to the BA list to find a cell that meets the preset conditions;

Specifically, after the mobile station camps on a cell, if the radio quality of an adjacent cell is better than that of the cell where the mobile station is currently camping on, the mobile station will trigger cell reselection and camp on a cell with better radio quality.

According to the 3GPP specification, the mobile station continuously calculates the values of C1 and C2 of the current camping cell and its neighboring cells. If any of the following criteria is met, the mobile station triggers cell reselection:

1) The wireless path loss of the cell where the cell resides is too large;

2) The downlink of the currently camped cell is faulty;

3), the current residential area is prohibited;

4) There is a better cell than the current camping cell in the same location area, or there is a better cell in another location area in the selected network;

5) The number of times of random access reaches the maximum number of retries broadcast on the BCCH, but still fails to successfully access the cell where it is currently camping.

Step 502, judge whether the received carrier is a BCCH carrier by searching for FCCH burst, if yes, then enter step 503;

Step 503, the mobile station decodes the SCH channel and synchronizes with the BCCH carrier, and obtains the BCCH information carried by the BCCH carrier; determines the cell access characteristic information of the cell to be joined corresponding to the BCCH information according to the BCCH information;

Specifically, the cell access feature information includes: cell access feature parameters and system messages broadcast by the base station;

The cell access characteristic parameters include: the minimum reception level allowed by the mobile station, the maximum power level of the control channel, the cell reselection offset, the cell reselection hysteresis and the LAC;

Step 504, judging whether the cell access characteristic parameter of the cell to be added is normal, if normal, enter step 505, otherwise enter step 508;

Here, it is the same as step 305 in the method shown in FIG. 3 , and will not be repeated here.

Step 505, judging whether the service function characteristics of the cell to be added are normal, if normal, enter step 506, otherwise enter step 508;

Here, it is the same as step 306 in the method shown in FIG. 3 , and will not be repeated here.

Step 506, judging whether the network configuration feature of the cell to be added is normal, if normal, enter step 507, otherwise enter step 508;

Here, it is the same as step 307 in the method shown in FIG. 3 and will not be repeated here.

Step 507, using the cell to be joined as the cell to reside on, accessing the cell to reside on, and ending the procedure;

Step 508, adjusting the cell to be added to the bottom of the BA list;

Step 509, judging whether all the cells in the BA list that meet the preset conditions have been tried, if not, go to step 510, and if all have been tried, go to step 511;

Step 510, tune to the next cell in the BA list that meets the preset conditions, and return to step 502;

Step 511, the mobile station uses the cell with the strongest carrier in the BA list as the cell to camp on, and accesses the cell to camp on.

Fig. 6 is a schematic structural diagram of a cell access device for preventing false base stations provided by an embodiment of the present invention; as shown in Fig. 6, the device includes: a first processing module, a second processing module, and a third processing module; wherein ,

The first processing module is configured to acquire a broadcast control channel BCCH carrier to be added to a cell after cell selection or cell reselection is triggered;

The second processing module is configured to decode the BCCH carrier to obtain BCCH information carried by the BCCH carrier, and determine the cell access characteristic information of the cell to be joined according to the BCCH information;

The third processing module is configured to judge whether the cell access feature information meets a preset condition, and if so, determine that the cell to be added is a cell not covered by a pseudo base station, and use the cell to be added as a resident The community is accessed.

Specifically, the third processing module is specifically configured to analyze the cell access feature information to obtain the minimum reception level allowed by the mobile station, the maximum power level of the control channel, the cell reselection offset, and the cell Reselection lag and/or location area code LAC;

When the minimum reception level allowed by the mobile station, the maximum power level of the control channel, the cell reselection offset, the cell reselection hysteresis and/or the LAC meet a preset threshold, then The preset conditions are met.

Specifically, when the minimum reception level allowed by the mobile station, the maximum power level of the control channel, the cell reselection offset, the cell reselection hysteresis and/or the LAC meet a preset threshold , the preset conditions are met, including at least one of the following situations:

If the minimum reception level allowed by the mobile station to access is less than a first threshold, the preset condition is met;

If the maximum power level of the control channel is greater than a second threshold, the preset condition is met;

If the cell reselection offset is greater than a third threshold, the preset condition is met;

If the cell reselection lag is greater than a fourth threshold, the preset condition is met;

If the LAC is not a set value, the preset condition is met.

Here, the first threshold may be -49, the second threshold may be 16, the third threshold may be 27, the fourth threshold may be 6, and the non-set value is not 0, 65535 value.

Specifically, the cell access feature information further includes: system messages broadcast by the base station;

The third processing module is further configured to analyze the system information broadcast by the base station, and if the Internet access capability information and neighboring cell information are obtained through analysis, the preset condition is met.

Specifically, the first processing module is also used to judge whether the mobile station stores a BCCH carrier, and if the BCCH carrier is stored, obtain the stored BCCH carrier as the BCCH carrier of the cell to be added;

If the BCCH carrier is not stored, the mobile station tunes to the carrier with the highest receiving level, judges whether the carrier is a BCCH carrier, and if it is a BCCH carrier, obtains the BCCH carrier as the BCCH carrier of the cell to be added.

Specifically, the third processing module is further configured to analyze the cell access feature information to obtain the network type, cell status and/or path loss criterion parameters of the cell to be joined;

When the network type belongs to the public land mobile network PLMN, the cell state is not disabled, and/or the path loss criterion parameter is greater than 0, it is determined that the cell to be joined is a cell not covered by a pseudo base station.

Specifically, the first processing module is further configured to judge whether the cell where the mobile station resides satisfies the cell reselection condition, and if so, reselect a cell that satisfies the preset condition from the broadcast control channel configuration BA list as the cell reselection condition. A cell to be joined, acquiring a BCCH carrier of the cell to be joined.

The above description is only a preferred embodiment of the present invention, and is not used to limit the protection scope of the present invention. Any modifications, equivalent replacements and improvements made within the spirit and principles of the present invention shall be included in the within the protection scope of the present invention.

Claims (14)

1. A method for preventing cell access of a pseudo base station, the method comprising:

after a mobile station triggers cell selection or cell reselection, acquiring a broadcast control channel BCCH carrier to be added into a cell;

decoding the BCCH carrier to obtain BCCH information carried by the BCCH carrier, and determining cell access characteristic information of the cell to be added according to the BCCH information;

and judging whether the cell access characteristic information meets a preset condition, if so, determining that the cell to be added is a cell not covered by the pseudo base station, and accessing the cell to be added as a resident cell.

2. The method of claim 1, wherein the determining whether the cell access characteristic information satisfies a preset condition comprises:

analyzing the cell access characteristic information to obtain the minimum receiving level, the maximum power level of a control channel, the cell reselection offset, the cell reselection hysteresis and/or the location area code LAC which are allowed to be accessed by the mobile station;

and when the minimum receiving level allowed to be accessed by the mobile station, the maximum power level of the control channel, the cell reselection offset, the cell reselection hysteresis and/or the LAC meet a preset threshold value, meeting the preset condition.

3. The method of claim 2, wherein the predetermined condition is satisfied when the minimum reception level allowed for the mobile station to access, the maximum power level of the control channel, the cell reselection offset, the cell reselection hysteresis, and/or the LAC satisfy a predetermined threshold, and wherein the predetermined condition comprises at least one of:

if the minimum receiving level allowed by the mobile station to access is less than a first threshold value, the preset condition is met;

if the maximum power level of the control channel is greater than a second threshold value, the preset condition is met;

if the cell reselection offset is greater than a third threshold, the preset condition is met;

if the cell reselection hysteresis is greater than a fourth threshold, the preset condition is met;

and if the LAC is not a set value, the preset condition is met.

4. The method of claim 2, wherein the cell access characteristic information further comprises: system information broadcasted by the base station;

the judging whether the cell access characteristic information meets a preset condition further comprises:

and analyzing the system message broadcasted by the base station, and if the system message is analyzed to obtain the internet surfing capability information and the neighbor cell information, meeting the preset condition.

5. The method of claim 1, wherein prior to obtaining the broadcast control channel, BCCH, carrier to be added to the cell, the method further comprises:

judging whether the mobile station stores BCCH carrier waves or not, if the BCCH carrier waves are stored, acquiring the stored BCCH carrier waves as the BCCH carrier waves of the cell to be added;

if not, the mobile station tunes to the carrier wave with the maximum receiving level, judges whether the carrier wave is the BCCH carrier wave, and if the carrier wave is the BCCH carrier wave, acquires the BCCH carrier wave as the BCCH carrier wave of the cell to be added.

6. The method of claim 1, wherein before determining that the cell to be added is a cell not covered by a pseudo base station, the method further comprises:

analyzing the cell access characteristic information to obtain the network type, the cell state and/or the path loss criterion parameter of the cell to be added;

and when the network type belongs to a Public Land Mobile Network (PLMN), the cell state is an un-forbidden state and/or the path loss criterion parameter is greater than 0, determining that the cell to be added is a cell covered by a non-pseudo base station.

7. The method of claim 1, wherein prior to obtaining the broadcast control channel, BCCH, carrier to be added to the cell, the method further comprises:

and judging whether the resident cell of the mobile station meets the cell reselection condition, if so, reselecting the cell meeting the preset condition from a broadcast control channel configuration (BA) list as a cell to be added, and acquiring the BCCH carrier of the cell to be added.

8. A cell access apparatus for preventing a pseudo base station, the apparatus comprising: the system comprises a first processing module, a second processing module and a third processing module; wherein,

the first processing module is used for acquiring a broadcast control channel BCCH carrier to be added into a cell after triggering cell selection or cell reselection;

the second processing module is configured to decode the BCCH carrier to obtain BCCH information carried by the BCCH carrier, and determine cell access characteristic information of the cell to be added according to the BCCH information;

the third processing module is configured to determine whether the cell access characteristic information meets a preset condition, and if so, determine that the cell to be added is a cell not covered by the pseudo base station, and access the cell to be added as a residential cell.

9. The apparatus of claim 8, wherein the third processing module is specifically configured to parse the cell access characteristic information to obtain a minimum receiving level allowed for access by the mobile station, a maximum power level of a control channel, a cell reselection offset, a cell reselection hysteresis, and/or a location area code LAC;

and when the minimum receiving level allowed to be accessed by the mobile station, the maximum power level of the control channel, the cell reselection offset, the cell reselection hysteresis and/or the LAC meet a preset threshold value, meeting the preset condition.

10. The apparatus of claim 9, wherein the predetermined condition is satisfied when a minimum reception level allowed for the mobile station to access, the maximum power level of the control channel, the cell reselection offset, the cell reselection hysteresis, and/or the LAC satisfy a predetermined threshold, and wherein the predetermined condition comprises at least one of:

if the minimum receiving level allowed by the mobile station to access is less than a first threshold value, the preset condition is met;

if the maximum power level of the control channel is greater than a second threshold value, the preset condition is met;

if the cell reselection offset is greater than a third threshold, the preset condition is met;

if the cell reselection hysteresis is greater than a fourth threshold, the preset condition is met;

and if the LAC is not a set value, the preset condition is met.

11. The apparatus of claim 9, wherein the cell access characteristic information further comprises: system information broadcasted by the base station;

the third processing module is further configured to analyze the system message broadcast by the base station, and if the system message is analyzed to obtain the internet access capability information and the neighboring cell information, the preset condition is met.

12. The apparatus of claim 8, wherein the first processing module is further configured to determine whether a BCCH carrier is stored in the mobile station, and if the BCCH carrier is stored, obtain the stored BCCH carrier as the BCCH carrier of the cell to be added;

if not, the mobile station tunes to the carrier wave with the maximum receiving level, judges whether the carrier wave is the BCCH carrier wave, and if the carrier wave is the BCCH carrier wave, acquires the BCCH carrier wave as the BCCH carrier wave of the cell to be added.

13. The apparatus of claim 8, wherein the third processing module is further configured to parse the cell access characteristic information to obtain a network type, a cell state, and/or a path loss criterion parameter of a cell to be added;

and when the network type belongs to a Public Land Mobile Network (PLMN), the cell state is an un-forbidden state and/or the path loss criterion parameter is greater than 0, determining that the cell to be added is a cell covered by a non-pseudo base station.

14. The apparatus of claim 8, wherein the first processing module is further configured to determine whether a cell where the mobile station resides satisfies a cell reselection condition, and if so, reselect a cell satisfying a preset condition from a broadcast control channel configuration (BA) list as a cell to be added, and acquire a BCCH carrier of the cell to be added.