CN103841630A - Method and device for controlling user equipment - Google Patents

Abstract

The invention discloses a method for controlling user equipment (UE) power, which includes: calculating in real time the Received Signal Code Power (RSCP) and Interference Signal Code Power (ISCP) of all UEs in the current time slot; state, obtain the historical ISCP of each UE in the corresponding state; use the ISCP and historical ISCP of each UE current time slot, and calculate the filtered ISCP of each UE according to the modified infinite impulse response filter (IIR) formula; use the ISCP of each UE The RSCP and the filtered ISCP calculate the signal-to-interference ratio (SIR) of each UE in the current time slot, and adjust the power of each UE according to the SIR. The invention also discloses a device for controlling UE power, which can ensure the accuracy of UE power control by a system adopting time-division scheduling, thereby improving the link performance of the system and ensuring system stability.

Description

Method and device for controlling user equipment power

technical field

The present invention relates to power control technology in the field of mobile communication, in particular to a method and device for controlling user equipment (UE, User Equipment) power.

Background technique

In recent years, in mobile communication systems using time-division scheduling, data services have grown explosively. Compared with the traditional voice service, the burstiness of the data service rises to the sub-frame (Sub-frame) or even the time slot (slot) level.

At present, the system using time-division scheduling controls the UE to increase or decrease the transmit power by calculating the signal-to-interference ratio (SIR, Signal to Interference Ratio) of the user equipment (UE, User Equipment). Wherein, in the method for calculating the SIR of the UE, the calculation of the interference power is assuming that the interference signal code power (ISCP, Interference Signal Code Power) is approximately Gaussian white noise, and the infinite impulse response filter (IIR, Infinite Impulse Response Filter ) filter the ISCP, and use the filtered ISCP as the interference power.

However, in a system using time-division scheduling, the UE will only send information in the Active state. When a certain UE switches from the Inactive state to the ACTIVE state, the transmit power of the UE will increase rapidly, causing the mobile The interference of the terminal to other mobile terminals also increases rapidly. Therefore, the ISCP will fluctuate greatly. If IIR is performed according to the above method, the accuracy of SIR calculation will be greatly affected, thereby affecting the accuracy of UE power control.

It can be seen that in a system using time-division scheduling in the prior art, due to low accuracy of UE power control, link performance of the system cannot be improved and system stability is affected.

Contents of the invention

In view of this, the purpose of the present invention is to provide a method and device for controlling UE power, which can ensure the accuracy of UE power control, thereby improving the link performance of the system using time-division scheduling and ensuring system stability.

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

The present invention provides a method for controlling UE power, the method comprising:

Real-time calculation of received signal code power (RSCP, Received Signal Code Power) and ISCP of all UEs in the current slot;

According to the state of each UE in the current time slot, obtain the historical ISCP of each UE in the corresponding state;

Using the ISCP of each UE's current time slot and the historical ISCP in the corresponding state, calculate the filtered ISCP of each UE according to the modified IIR formula;

Using the RSCP of each UE and the filtered ISCP, calculate the SIR of each UE in the current time slot, and adjust the power of each UE according to the SIR.

In the above solution, all UEs in the current time slot include: UEs in the Active state in the current time slot, and one or more UEs in different Inactive states in the current time slot.

In the above scheme, the acquisition of the historical ISCP in the corresponding state of each UE includes: the base station (BS, Base Station) extracts the identifiers of each UE in the current time slot one by one, and from the historical ISCP record table corresponding to the identifier of the UE, Finding whether there is one or more filtered ISCPs in the same state as the UE, if so, extracting the one or more filtered ISCPs for weighted accumulation to obtain the historical ISCP in the corresponding state of the UE; if If not, use the preset initial value of historical ISCP as the historical ISCP in the corresponding state of the UE; and so on until the historical ISCP in the corresponding state of all UEs in the current time slot is obtained.

In the above solution, the modified IIR formula is as follows: the ISCP of the last time slot in the IIR formula is replaced with the historical ISCP in the corresponding state to obtain the modified IIR formula.

In the above solution, after calculating and obtaining the filtered ISCP of each UE according to the modified IIR formula, the method further includes:

The BS extracts the identifiers of each UE in the current time slot one by one, checks whether it has a historical ISCP record table corresponding to the extracted UE identifiers, if not, then checks the UE's status in the current time slot, current time, and filtering The last ISCP is stored in the historical ISCP record table corresponding to the identity of the UE;

If so, then check the number of filtered ISCPs stored in the historical ISCP record table corresponding to the UE, and if the number of filtered ISCPs corresponding to the UE is less than the ISCP saved number threshold, then the UE is placed in the current The state of the time slot, the current time, and the filtered ISCP are stored in the historical ISCP record table corresponding to the UE's identity; if the number of stored filtered ISCPs corresponding to the UE is equal to or greater than the threshold value of the saved number of ISCPs, the record is deleted The record with the earliest time saves the state of the UE in the current time slot, the current time, and the filtered ISCP in the historical ISCP record table corresponding to the identity of the UE.

The present invention also provides a device for controlling UE power, which includes: a power calculation module, a filtering module, an SIR calculation module and a power control module; wherein,

The power calculation module is used to calculate the RSCP and ISCP of all UEs in the current time slot in real time, send the ISCPs of all UEs to the filtering module, and provide the RSCP of each UE for the SIR calculation module;

The filter module is used to obtain the historical ISCP of each UE in the corresponding state according to the state of each UE in the current time slot after receiving the ISCP of all UEs sent by the calculation module, and use the ISCP of each UE in the current time slot and the corresponding state The historical ISCP of each UE is calculated according to the modified IIR formula to obtain the filtered ISCP of each UE, and the filtered ISCP of each UE is sent to the SIR calculation module;

The SIR calculation module is used to extract the RSCP corresponding to each UE from the power calculation module after receiving the filtered ISCP of each UE from the filtering module, and calculate each UE in the current time slot by using the RSCP of each UE and the filtered ISCP SIR, sending the SIR to the power control module;

The power control module is configured to adjust the power of each UE according to the SIR sent by the SIR calculation module.

In the above solution, the power calculation module is specifically configured to use the UE in the Active state in the current time slot and one or more UEs in different Inactive states in the current time slot as all UEs in the current time slot.

In the above solution, the filtering module is specifically used to extract the identifiers of each UE in the current time slot one by one, and find out whether there is one or If there are a plurality of filtered ISCPs, extract the one or more filtered ISCPs for weighted accumulation to obtain the historical ISCP in the corresponding state of the UE; if not, use the preset initial value of the historical ISCP as the The historical ISCP in the corresponding state of the UE; and so on, until the historical ISCP in the corresponding state of all UEs in the current time slot is obtained.

In the above solution, the filtering module is specifically configured to replace the ISCP of the last time slot in the IIR formula with the historical ISCP in the corresponding state to obtain the modified IIR formula.

In the above scheme, the power control module is also used to extract the identifiers of each UE in the current time slot one by one, check whether it has a historical ISCP record table corresponding to the extracted UE identifiers, if not, then the The state of the UE in the current time slot, the current time, and the filtered ISCP are stored in the historical ISCP record table corresponding to the UE's identity;

If so, then check the number of filtered ISCPs stored in the historical ISCP record table corresponding to the UE, and if the number of filtered ISCPs corresponding to the UE is less than the ISCP saved number threshold, then the UE is placed in the current The state of the time slot, the current time, and the filtered ISCP are stored in the historical ISCP record table corresponding to the UE's identity; if the number of stored filtered ISCPs corresponding to the UE is equal to or greater than the threshold value of the saved number of ISCPs, the record is deleted The record with the earliest time saves the state of the UE in the current time slot, the current time, and the filtered ISCP in the historical ISCP record table corresponding to the identity of the UE.

The method and device for controlling UE power provided by the present invention can distinguish the different states of each UE in the current time slot, obtain the historical ISCP in the corresponding state of each UE, and then use the ISCP of each UE in the current time slot and the history in the corresponding state ISCP, the filtered ISCP is calculated according to the modified IIR formula; in this way, a more accurate filtered ISCP for each UE can be obtained, and then the more accurate filtered ISCP is used for SIR calculation and UE power calculation In this way, the accuracy of UE power control can be guaranteed, thereby improving the link performance of the system using time-division scheduling and ensuring system stability.

Description of drawings

FIG. 1 is a schematic flowchart of a method for controlling UE power according to the present invention;

FIG. 2 is a schematic structural diagram of a device for controlling UE power according to the present invention.

Detailed ways

The basic idea of the present invention is: calculate the RSCP and ISCP of all UEs in the current time slot in real time; obtain the historical ISCP of each UE in the corresponding state according to the state of each UE in the current time slot; use the ISCP and the corresponding According to the historical ISCP in the state, the filtered ISCP of each UE is calculated according to the modified IIR formula; the SIR of each UE in the current time slot is calculated by using the RSCP of each UE and the filtered ISCP, and the SIR is performed on each UE according to the SIR power adjustment.

The present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments.

The method for controlling UE power proposed by the present invention, as shown in Figure 1, includes the following steps:

Step 101: Calculate RSCP and ISCP of all UEs in the current time slot in real time.

Here, the calculation of the RSCP and ISCP of all UEs in the current time slot is an operation performed by the BS specified in the prior art, and will not be repeated here;

All UEs in the current time slot include: UEs in the Active state in the current time slot, and one or more UEs in different Inactive states in the current time slot;

Wherein, the UEs in different Inactive states are states that only use a dedicated physical control channel (DPCCH, Dedicated Physical Control Channel) to send information, and there are different Inactive states according to different UEs currently in an Active state, for example: if The BS allocates four UEs to use different time slots, which are UE-A, UE-B, UE-C and UE-D respectively. Then each UE has different time slots in different time slots as the activation state of itself and other UEs changes. Four states, taking UE-A as an example, UE-A is in Active state when sending data, when UE-B is in Active state, UE-A is in Inactive-1 state; when UE-C is in Active state, UE- A is in the Inactive-2 state; when UE-D is in the Active state, UE-A is in the Inactive-3 state, and so on.

The time slot in which the UE is in the Active state is the uplink time slot allocated by the BS specified in the prior art, which will not be described in detail here.

Step 102: According to the state of each UE in the current time slot, obtain the historical ISCP of each UE in a corresponding state.

Here, the state of the UE in the current time slot includes: the Active state and the corresponding different Inactive states, the acquisition method of which is the existing technology, and will not be described here;

The acquisition of the historical ISCP in the corresponding state of each UE is as follows: the BS extracts the identifiers of each UE in the current time slot one by one, and searches whether there is an ISCP in the same state as the UE from the historical ISCP record table corresponding to the identifier of the UE. One or more filtered ISCPs, if there are, extract the one or more filtered ISCPs for weighted accumulation to obtain the historical ISCP in the corresponding state of the UE; if not, use the preset historical ISCP initial The value is used as the historical ISCP in the corresponding state of the UE; and so on, until the historical ISCP in the corresponding state of all UEs in the current slot is obtained;

Wherein, the identifier of the UE may be an International Mobile Subscriber Identification Number (IMSI, International Mobile Subscriber Identification Number) of the UE; the initial value of the historical ISCP may be set to zero, or may be a value set according to actual conditions; The weighted accumulation is a prior art, and will not be repeated here.

Step 103: Using the ISCP of the current time slot of each UE and the historical ISCP in the corresponding state, calculate the filtered ISCP of each UE according to the modified IIR formula.

Here, the modified IIR formula is: replace the ISCP of the last time slot in the IIR formula with the historical ISCP in the corresponding state, for example, to perform IIR calculation for the UE in the Active state in the current time slot, use the following formula calculate:

ISCP _ACTIVE (l)=α·ISCP _SLOT (l)+(1-α)·ISCP _ACTIVE ; wherein, ISCP _ACTIVE (l) represents the ISCP filtered by the UE when the current time slot is in the Active state, and l represents the current time slot Number; α represents the filter coefficient; ISCP _SLOT (1) represents the ISCP of the current time slot calculated in step 101; ISCPA _CTIVE represents the historical ISCP of the UE in the Active state.

Perform IIR calculation for the UE in the Inactive state in the current time slot, and use the following formula for calculation:

ISCP _INACTIVE(n) (l)=α ISCP _SLOT (l)+(1-α) ISCP _INACTIVE(n) ; where, ISCP _INACTIVE(n) (l) indicates that the current time slot is in the Inactive-n state UE In the filtered ISCP, l represents the number of the current time slot; the Inactive-n state is the corresponding nth Inactive state according to the UE currently in the Active state; α represents the filter coefficient; ISCP _SLOT (l) represents the step The ISCP of the current time slot calculated in 101; ISCP _INACTIVE(n) represents the historical ISCP of the UE in the nth Inactive state, where the value range of n is the same as the number of different Inactive states that can be determined in the current time slot.

Further, after the above step 103 is completed, the BS extracts the identifiers of each UE in the current time slot one by one, and checks whether there is a historical ISCP record table corresponding to the extracted UE identifiers, if not, then the UE is placed in the current time slot. The state of the time slot, the current time and the filtered ISCP are stored in the historical ISCP record table corresponding to the UE's identity;

If so, then check the number of filtered ISCPs stored in the historical ISCP record table corresponding to the UE, and if the number of filtered ISCPs corresponding to the UE is less than the ISCP saved number threshold, then the UE is placed in the current The state of the time slot, the current time, and the filtered ISCP are stored in the historical ISCP record table corresponding to the UE's identity; if the number of stored filtered ISCPs corresponding to the UE is equal to or greater than the threshold value of the saved number of ISCPs, the record is deleted The record with the earliest time saves the state of the UE in the current time slot, the current time, and the filtered ISCP in the historical ISCP record table corresponding to the identity of the UE. Wherein, the ISCP saving quantity threshold value is a preset value according to the actual situation.

Step 104: Calculate the SIR of each UE in the current time slot by using the RSCP of each UE and the filtered ISCP, and adjust the power of each UE according to the SIR.

Here, the calculation of the SIR of each UE in the current time slot is: the SIR is obtained by dividing the RSCP of each UE calculated in step 101 by the filtered ISCP of the UE, which is a prior art.

The power adjustment of each UE according to the SIR is an existing technology, which may be: the BS compares the SIR of each UE with its own preset signal-to-interference ratio target value (SIR_Target), and if the SIR is smaller than SIR_Target, the BS notifies The UE increases the transmit power; if the SIR is greater than or equal to SIR_Target, the BS notifies the UE to decrease the transmit power.

As shown in FIG. 2, the present invention provides a device for controlling UE power, which includes: a power calculation module 21, a filtering module 22, an SIR calculation module 23, and a power control module 24; wherein,

The power calculation module 21 is used to calculate the RSCP and ISCP of all UEs in the current time slot in real time, send the ISCPs of all UEs to the filtering module 22, and provide the RSCP of each UE for the SIR calculation module 23;

Filtering module 22, after receiving the ISCP of all UEs sent by the calculation module, according to the state of each UE in the current time slot, obtain the historical ISCP of each UE in the corresponding state, and use the ISCP and corresponding state of each UE's current time slot The following historical ISCP is calculated according to the modified IIR formula to obtain the filtered ISCP of each UE, and sends the filtered ISCP of each UE to the SIR calculation module 23;

The SIR calculation module 23 is used to extract the RSCP corresponding to each UE from the power calculation module 21 after receiving the filtered ISCP of each UE from the filtering module 22, and calculate the current time by using the RSCP of each UE and the filtered ISCP. SIR of each UE, and send the SIR to the power control module 24;

The power control module 24 is configured to adjust the power of each UE according to the SIR sent by the SIR calculation module 23 .

The power calculation module 21 is specifically configured to determine the state of each UE in the current time slot, including a UE in an Active state, and one or more UEs in a different Inactive state, and the UEs in a different Inactive state In order to only use DPCCH to send information, UEs in different Inactive states have different Inactive states depending on the UE currently in Active state. For example: if four UEs are allocated to use different time slots, UE-A , UE-B, UE-C, and UE-D, each UE has four states in different time slots as the activation state of itself and other UEs changes. Taking UE-A as an example, UE-A sends When the data is in the Active state, when UE-B is in the Active state, UE-A is in the Inactive-1 state; when UE-C is in the Active state, UE-A is in the Inactive-2 state; when UE-D is in the Active state , UE-A is in the Inactive-3 state, and so on.

The power calculation module 21 is also configured to send the ISCPs of all UEs to the filtering module 22, and at the same time, send the state of each UE in the current time slot to the filtering module 22; correspondingly, the filtering module 22 is also used to The state of each UE in the current time slot sent by the power calculation module 21 is received, and the state of the current time slot is saved in a record corresponding to the identity of each UE.

The filtering module 22 is specifically configured to extract the identifiers of each UE in the current time slot one by one, and find out whether there are one or more filter IDs in the same state as the UE from the historical ISCP record table corresponding to the identifier of the UE. After the ISCP, if there is, then extract the one or more filtered ISCPs for weighted accumulation to obtain the historical ISCP in the corresponding state of the UE; if not, use the preset initial value of the historical ISCP as the UE The historical ISCP in the corresponding state; and so on, until the historical ISCP in the corresponding state of all UEs in the current time slot is obtained.

The filtering module 22 is specifically used to replace the ISCP of the last time slot in the IIR formula in the prior art with the historical ISCP in the corresponding state to obtain the modified IIR formula, for example, for the UE in the Active state of the current time slot For IIR calculation, use the following formula to calculate:

ISCP _ACTIVE (l)=α·ISCP _SLOT (l)+(1-α)·ISCP _ACTIVE ; wherein, ISCP _ACTIVE (l) represents the ISCP filtered by the UE when the current time slot is in the Active state, and l represents the current time slot Number; α indicates the filter coefficient; ISCP _SLOT (l) indicates the ISCP of the current time slot; ISCP _ACTIVE indicates the historical ISCP of the UE in the Active state.

Perform IIR calculation for the UE in the Inactive state in the current time slot, and use the following formula for calculation:

ISCP _INACTIVE(n) (l)=α ISCP _SLOT (l)+(1-α) ISCP _INACTIVE(n) ; where, ISCP _INACTIVE(n) (l) indicates that the current time slot is in the Inactive-n state UE In the filtered ISCP, l represents the number of the current time slot; the Inactive-n state is the corresponding nth Inactive state according to the UE currently in the Active state; α represents the filter coefficient; ISCP _SLOT (l) represents the current ISCP of the time slot; ISCP _INACTIVE(n) indicates the historical ISCP of the UE in the nth Inactive state.

The filtering module 22 is also used to extract the ID of each UE in the current time slot, check whether there is a historical ISCP record table corresponding to the ID of the extracted UE in itself, if not, then the UE in the current time slot The status, current time, and filtered ISCP are stored in the historical ISCP record table corresponding to the UE's identity; if there is, check that the number of filtered ISCP stored in the historical ISCP record table corresponding to the UE is less than the ISCP saved If the number threshold value, the state of the UE in the current time slot, the current time, and the filtered ISCP are stored in the historical ISCP record table corresponding to the UE's identity; if the number of the stored filtered ISCP corresponding to the UE is equal to or If it is greater than the ISCP saving threshold value, delete the record with the earliest record time, and then save the state of the UE in the current time slot, the current time, and the filtered ISCP in the historical ISCP record table corresponding to the UE's identity. Wherein, the ISCP saving quantity threshold value is a preset value according to the actual situation.

The power control module 24 is specifically configured to compare the SIR of each UE with its own preset SIR_Target, if the SIR is smaller than the SIR_Target, notify the UE to increase the transmit power; if the SIR is greater than or equal to the SIR_Target, notify the UE to decrease the transmit power.

The above device can be installed as a logic module in the BS of the system adopting time division scheduling.

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the protection scope of the present invention.

Claims (10)

1. A method for controlling power of a User Equipment (UE), the method comprising:

calculating the Received Signal Code Power (RSCP) and the Interference Signal Code Power (ISCP) of all UE in the current time slot in real time;

acquiring historical ISCP (interference Signal Power control protocol) of each UE in a corresponding state according to the state of each UE in the current time slot;

calculating to obtain the ISCP filtered by each UE according to the modified IIR formula by using the ISCP of each UE at the current time slot and the historical ISCP in the corresponding state;

and calculating the signal-to-interference ratio (SIR) of each UE in the current time slot by using the RSCP of each UE and the filtered ISCP, and adjusting the power of each UE according to the SIR.

2. The method of claim 1, wherein all UEs in the current time slot comprise: the UE in the Active state of the current time slot, and one or more UEs in different Inactive states of the current time slot.

3. The method according to claim 1 or 2, wherein the obtaining the historical ISCP in the corresponding state of each UE comprises: the base station BS extracts the identifications of each UE in the current time slot one by one, searches whether one or more filtered ISCP (interference Signal code Power) in the same state as the UE exist in a historical ISCP record table corresponding to the identification of the UE, and extracts the one or more filtered ISCP to carry out weighted accumulation if the one or more filtered ISCP exists, so as to obtain the historical ISCP in the corresponding state of the UE; if not, using the initial value of the preset historical ISCP as the historical ISCP in the corresponding state of the UE; and repeating the steps until historical ISCP under the corresponding state of all the UE in the current time slot is obtained.

4. The method of claim 1, wherein the modified IIR formula is: and replacing the ISCP of the last time slot in the IIR formula with the historical ISCP in the corresponding state to obtain the modified IIR formula.

5. The method according to claim 1 or 4, wherein after calculating the filtered ISCP of each UE according to the modified IIR formula, the method further comprises:

BS extracts the ID of each UE in current time slot one by one, checks whether the ID has history ISCP record table corresponding to the extracted ID of UE, if not, then stores the state of the UE in current time slot, current time and filtered ISCP in the history ISCP record table corresponding to the ID of the UE;

if yes, checking the number of the filtered ISCP in the historical ISCP record table corresponding to the UE, and if the number of the filtered ISCP corresponding to the UE is smaller than an ISCP storage number threshold value, storing the state of the UE at the current time slot, the current time and the filtered ISCP in the historical ISCP record table corresponding to the identity of the UE; and if the filtered ISCP number corresponding to the UE is equal to or greater than the ISCP storage number threshold value, deleting a record with the earliest recording time, and storing the state of the UE in the current time slot, the current time and the filtered ISCP in a historical ISCP record table corresponding to the identity of the UE.

6. An apparatus for controlling power of a UE, the apparatus comprising: the device comprises a power calculation module, a filtering module, an SIR calculation module and a power control module; wherein,

the power calculation module is used for calculating RSCP and ISCP of all UE in the current time slot in real time, sending the ISCP of all UE to the filtering module and providing RSCP of each UE for the SIR calculation module;

the filtering module is used for acquiring the historical ISCP of each UE in the corresponding state according to the state of each UE in the current time slot after receiving the ISCP of all the UEs sent by the calculating module, calculating the filtered ISCP of each UE according to the modified IIR formula by using the ISCP of each UE in the current time slot and the historical ISCP in the corresponding state, and sending the filtered ISCP of each UE to the SIR calculating module;

an SIR calculation module, configured to extract, after receiving the ISCP filtered by each UE from the filtering module, the RSCP corresponding to each UE from the power calculation module, calculate an SIR of each UE in the current time slot by using the RSCP of each UE and the filtered ISCP, and send the SIR to the power control module;

and the power control module is used for adjusting the power of each UE according to the SIR sent by the SIR calculation module.

7. The apparatus of claim 6, wherein the power calculation module is specifically configured to use a UE in an Active state in a current timeslot and one or more UEs in different Inactive states in the current timeslot as all UEs in the current timeslot.

8. The apparatus of claim 7,

the filtering module is specifically configured to extract identifiers of UEs in a current time slot one by one, search, from a history ISCP record table corresponding to the identifier of the UE, whether one or more filtered ISCPs in the same state as the UE exist, and if so, extract the one or more filtered ISCPs for weighted accumulation to obtain a history ISCP in a state corresponding to the UE; if not, using the initial value of the preset historical ISCP as the historical ISCP in the corresponding state of the UE; and repeating the steps until historical ISCP under the corresponding state of all the UE in the current time slot is obtained.

9. The apparatus of claim 8, wherein the filtering module is specifically configured to replace the ISCP of the previous time slot in the IIR formula with the historical ISCP in the corresponding state to obtain the modified IIR formula.

10. The apparatus of claim 6,

the power control module is further configured to extract identifiers of the UEs in the current time slot one by one, check whether a historical ISCP record table corresponding to the extracted UE identifier exists, and if not, store the state of the UE in the current time slot, the current time, and the filtered ISCP in the historical ISCP record table corresponding to the UE identifier;

if yes, checking the number of the filtered ISCP in the historical ISCP record table corresponding to the UE, and if the number of the filtered ISCP corresponding to the UE is smaller than an ISCP storage number threshold value, storing the state of the UE at the current time slot, the current time and the filtered ISCP in the historical ISCP record table corresponding to the identity of the UE; and if the filtered ISCP number corresponding to the UE is equal to or greater than the ISCP storage number threshold value, deleting a record with the earliest recording time, and storing the state of the UE in the current time slot, the current time and the filtered ISCP in a historical ISCP record table corresponding to the identity of the UE.

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