CN100411477C - Access Control Method in Mobile Communication System - Google Patents

Abstract

The present invention relates to technology of mobile communication and discloses an access control method of a mobile communication system. The access success rate of high-priority users is ensured under the condition of system overload so as to improve the operation performance of the mobile communication system. In the present invention, the condition of system load is monitored; when the overload happens, the access successful rate of the high-grade users is ensured by assigning more resources to the high-grade users and less resources to low-grade users.

Description

Access Control Method in Mobile Communication System

technical field

The invention relates to mobile communication technology, in particular to an access control method in a mobile communication system.

Background technique

With the advancement of mobile communication technology, the number of mobile users has increased rapidly, which has brought new pressure to mobile communication systems, especially higher requirements for access control technology in mobile communication systems. The access control technology is a method for controlling the access of a user equipment (User Equipment, referred to as "UE") to a wireless channel in a mobile communication system.

The access control technology in the mobile communication system is briefly described below. In a mobile communication system, when a UE moves in each adjacent cell, after entering a certain cell to complete location registration, the UE will reside in the cell and enter an idle state. This cell is also called the UE's current cell. district. In the idle state, if the UE performs the cell location update process, or needs to respond to the paging from the cell, or needs to establish a call with other users, including service requests, sending short message requests, etc., the UE will send a message to the base station of the current cell. Access request. It should be noted that the random access procedure is initiated by the UE. The UE sends an access request to the base station of the cell on a random access channel to perform an access probe. When the network side receives the access request from the mobile station, it sends a channel assignment message to the UE on a common channel, and then the UE and the base station perform data interaction on the assigned specific channel. It should also be noted that the random access process initiated by the UE is completed according to the access resources of the base station of the current cell and according to a specific algorithm. The UE selects an access slot from the available access resources. This selection is random. After the base station receives the access probe from the mobile station, the cell base station sends an access indication message to the UE, indicating whether the current UE is Access is successful. If the random access is unsuccessful, the UE cannot perform data interaction with the current cell, and cannot complete functions of a call or data transmission.

In the current mobile communication system, there is always one current cell where the UE resides, and the access slot resources of a cell base station are limited. When multiple UEs access a base station at the same time, and randomly select the same access slot When time slots are used, access conflicts are likely to occur, resulting in failure of the access process, especially in densely populated cities and hotspot areas.

In the prior art, in the random access channel (Random Access CHannel, referred to as "RACH") access process, according to the priority level of the user's access to the system, different access resources are given to the UE corresponding to the user, such as more The access sub-channel enables users with high priority to access the system to access the network faster.

The specific process of processing UE random access in the prior art will be described below in conjunction with FIG. 1 .

First, in step 100, the UE determines an access slot and a preamble signature. According to the mapping relationship between the Access Class (AC for short) and the Access Service Class (ASC for short) in the access parameters and the UE stored in the Subscriber Identification Module (Subscriber Identification Module, "SIM") and the AC information in the User Service Identity Module (User Service entityModule, referred to as "USIM") to determine the available sub-channel set, and select one of the sub-channels to determine the available access slot set, and then An access slot is chosen, the set of available preamble signatures is determined, and another preamble signature is chosen. It should be noted that AC information is stored in the UE, and the range of AC is 0 to 15, and 15 has the highest priority, and the radio network controller provides the mapping relationship between AC and ASC in the system message. Among them, in the protocol 25331 of the WCDMA standard, in order to divide the access channel resources, ASC is defined. ASC is divided into 8 categories from 0 to 7, with 0 being the highest, and each category corresponds to the Physical Random Access Channel (Physical Random Access Channel). Channel, referred to as "PRACH") channel resource allocation method. The UE reads the system information, and can obtain its own ASC number according to the mapping relationship between AC and ASC, and then obtain the subchannel number that can be accessed. When the UE performs the cell location update process, or needs to respond to the paging from the cell, or The UE needs to establish calls with other users, including service requests, requests for sending short messages, etc., then the UE will send an access request to the base station of the current cell. Before the UE accesses the mobile communication system, it must first check to ensure that the access parameters received from the base station are current. The access parameters include persistent parameters (0-9, 10-15), persistent modifiers, and initial access parameters. Power requirements, number of access channels, number of preamble signatures, maximum length of access messages, values for various overload categories, access attempt compensation parameters, etc. After the UE updates the parameters or determines that the parameters are current, the UE starts the access procedure.

Subsequently, in the next step 110, the UE measures the power level of the downlink, and calculates the initial preamble power according to parameters such as pilot transmission power and uplink interference. The first access attempt is transmitted at this power level, And each subsequent access attempt is transmitted at a specific amount of higher power level than the previous access attempt before entering step 120 .

In step 120, the UE sets the preamble retransmission counter, and sets the preamble retransmission counter to the maximum value of the preamble retransmission "Preamble Retrans Max", which can be directly obtained from the system parameters. Then, go to step 130 .

In step 130 , the UE transmits the selected preamble signature on the access slot, and proceeds to step 140 .

In step 140, the UE decodes the Acquisition Indicator Channel (AICH for short), and checks whether the base station has detected the preamble. If an Acquisition Indicator ("AI" for short) is received, the physical random access process is exited in the next step 150. If the acknowledgment AI is received, the message part of the random access is sent in the subsequent step 160, and the physical random access process is thus completed. If no AI is received, go to step 170 . In step 170, the UE reselects available access slots and preamble signatures, and performs corresponding processing on the transmit power retransmission counter of the preamble. It should be noted that the processing here needs to increase the transmission power of the preamble by a power increase step size "Power Ramp Step", and decrease the retransmission counter by 1. If it is reduced to zero, the physical random access process will be exited, otherwise it will need to send new lead.

In practical applications, the above solution has the following problems: in the current mobile communication system, when the system load is too heavy, the system load will further increase and deteriorate with the continuous access requests of the UE, and the mobile The communication system cannot differentiate access to users with different priorities, resulting in high-priority users being unable to establish a connection with the current cell base station to achieve normal communication just like ordinary low-priority users, which affects the performance of the mobile communication system, and Increased level of complaints from high-priority users about system operations.

The main reason for this situation is that the access control of the mobile communication system in the prior art does not consider the overload situation, but only provides corresponding access resources according to the user level, and cannot dynamically adjust the access resources according to the current load situation. resources, so the access success rate of high-level users cannot be guaranteed when overloaded.

Contents of the invention

In view of this, the main purpose of the present invention is to provide an access control method in a mobile communication system, so that in the case of system overload, the access success rate of high-priority users is ensured, thereby improving the operational performance of the mobile communication system .

To achieve the above object, the present invention provides an access control method in a mobile communication system, comprising the following steps:

The system dynamically monitors the load of each cell, and when a cell is overloaded, it adjusts the system parameters that affect the success probability of users accessing the overloaded cell, so that the access success probability of high-level users is increased, and the access success probability of low-level users is reduced .

Wherein, the system parameter is a wireless channel access parameter to be read by a user who selects a channel on the cell to initiate access, including a persistence scale factor parameter value, a dynamic persistence level parameter value, and an access resource parameter.

When cell overload occurs, the step of adjusting system parameters includes the following sub-steps:

Increase the persistence scale factor parameter value of high-level users, reduce the dynamic persistence level parameter value of high-level users, and increase the access resources of high-level users;

Reduce the parameter value of persistence scale factor for low-level users, increase the dynamic persistence level parameter value of low-level users, and reduce the access resources of low-level users.

When the cell load is low, adjust the system parameters that affect the success probability of users accessing the overloaded cell. Under the premise that the access success probability of low-level users is not higher than that of high-level users, the The user's access success probability is increased, and the high-level user's access success probability is reduced.

When the cell load is low, the step of adjusting the system parameters includes the following sub-steps:

On the premise that the persistence scale factor parameter value of high-level users is lower than that of low-level users, increase the persistence scale factor parameter value of high-level users and decrease the persistence scale factor parameter value of low-level users;

Under the premise that the dynamic persistence level parameter value of high-level users is higher than the persistence scale factor parameter value of low-level users, reduce the dynamic persistence level parameter value of high-level users, and reduce the persistence scale factor parameter value of low-level users;

On the premise that high-level users have more access resources than low-level users, increase the access resources of high-level users and reduce the access resources of low-level users.

The access resource parameters include an access time slot of the access resource and a preamble signature of the access resource.

The step of the system dynamically monitoring the load situation of each cell further includes the following sub-steps:

The system issues an instruction to measure the load index of each cell;

The corresponding system measurement module responds to the instruction, measures the load condition of each cell according to the instruction, and reports it.

Through comparison, it can be found that the main difference between the technical solution of the present invention and the prior art is that the prior art does not consider whether the system is overloaded, but only ensures that high-level users can access at a faster speed through the allocation of access resources. However, the present invention first monitors the system overload situation, and when overload occurs, allocates more resources to high-level users and allocates less resources to low-level users to ensure the access success rate of high-level users.

The difference in this technical solution brings obvious beneficial effects, that is, the present invention implements an effective access control method in the mobile communication system, so that when the system is overloaded, the access control method when the system is overloaded Access control, and adjust system parameters through system messages, on the one hand, solves the problem of further increase of system overload in the prior art, avoids the deep deterioration of system overload, and on the other hand, can effectively limit or even reject low-priority Access requests of high-priority users, and try not to affect the access requests of high-priority users, so that the mobile communication system can provide differentiated services to users of different priority levels, and always ensure the successful access rate of high-priority users.

Description of drawings

FIG. 1 is a schematic flow chart of processing random access of user equipment in the prior art;

FIG. 2 is a schematic flowchart of a method for implementing access control according to an embodiment of the present invention;

Fig. 3 is a schematic flowchart of system parameter control and adjustment in the access control method according to an embodiment of the present invention.

Detailed ways

In order to make the object, technical solution and advantages of the present invention clearer, the present invention will be further described in detail below in conjunction with the accompanying drawings.

In general, the present invention realizes that in the case of system overload, further increase of the system load can be avoided, and at the same time, the mobile communication system can realize different priority Differentiated services for high-level users.

Specifically, the present invention monitors the load of the cell by the system, and adjusts the system parameter value according to the system load, so that low-priority users allocate less resources for accessing the cell or even prohibit low-priority users from accessing, while Ensure that high-priority users can be allocated more resources for accessing the cell, thereby avoiding the further increase of the system overload problem in the case of system overload, and at the same time ensuring the successful access of high-priority users The rate realizes the differentiated service of the mobile communication system for users with different priorities.

Fig. 2 shows a specific flow of implementing an access control method in a mobile communication system according to an embodiment of the present invention.

First of all, in step 200, the mobile communication system issues an instruction to measure the load indicators of each cell, thereby enabling the system to monitor the cell load function. By monitoring the cell load in this way, the latest situation of the system load can be grasped in real time, and effective control can be implemented for the system. Access provides timely information. Then, go to step 210 .

In step 210, after receiving the instruction, the corresponding measurement module in the system measures the load condition of each cell in the network according to the specific requirements of the instruction, and reports the specific load condition. Through such processing, the system can grasp the current load information of each cell in a timely manner, understand the operating status of the system in real time, and control and deal with the abnormal overload of a cell in the network in a timely and effective manner. Next, go to step 220 .

In step 220 , after receiving the reported load index parameters of each cell, the system records the current load situation of each cell on the network side, and proceeds to step 240 .

In step 240, according to the load situation in the mobile communication system, and the access service class (Access Service Class, "ASC") corresponding to the user equipment (User Equipment, referred to as "UE") that needs to access the cell, through Adjust system parameters to achieve effective control of users with different priorities when they access the system, and ensure the stability of system operation while realizing differentiated services. It should be noted that the UE mentioned here refers to various fixed or mobile terminals capable of accessing a mobile communication system, such as mobile phones and notebooks.

It should be noted that if the cell load exceeds the preset overload threshold, the system parameter value of the cell should be adjusted appropriately. The system parameters configured on the network side that need to be adjusted include the persistence scaling factor parameter value "Persistence scaling factor", the dynamic persistence level parameter value "Dynamicpersistence level" and access resource parameters. Among them, the persistence scaling factor parameter value "Persistencescaling factor" and the dynamic persistence level parameter value "Dynamic persistence level" refer to the parameters that control the access probability when the user initiates access on the wireless channel; The resources that can be used by the access include the access slot "Access slot" of the access resource and the preamble signature "Preamble signature" of the access resource. By adjusting these system parameters, the mobile communication system can effectively control users with different priorities when accessing the system according to the current system load. For example, when the system load is too high, the above system parameters can be adjusted. Allocate less access resources for low-priority users, reduce their access probability in the current situation and effectively ensure the successful access rate of high-priority users. It should also be noted that the system parameters to be adjusted may not be limited to the above-mentioned parameters, as long as the access probability of low-priority users can be reduced and the access probability of high-priority users can be guaranteed.

Therefore, through the processing of the above-mentioned solution of the present invention, it can be seen that the system parameters can be output to influence users with different priorities to access the cell, so as to achieve effective control of users in the access phase when the system is overloaded, and avoid There is a problem in the technology that the system load will increase further when the system load is too heavy, and at the same time, it can realize the differentiated service of the mobile communication system for users with different priorities, and try not to affect the access of high-end users when overloaded.

The specific process of system parameter control and adjustment in the access control method of an embodiment of the present invention will be described below in conjunction with FIG. 3 .

First in step 300, the system detects whether the current cell load is too high, which is obtained by comparing the current cell load with the preset system overload threshold, if the current cell load exceeds the overload threshold, then It indicates that the system load is too high, so go to the previous step 310 , otherwise go to step 320 .

In step 310, because the current cell load is too high, it is necessary to reduce the persistence scaling factor "Persistence scaling factor" corresponding to the UE of the low-ASC user, and increase the dynamic persistence level "Dynamic persistence level" of the low-ASC user, and then reduce The access resources available in the UE of the low-ASC user, that is, to reduce the available access slot "Access slot" and the preamble signature "Preamble signature" of the available access resources. The above-mentioned adjustments to the system parameters can effectively avoid further deterioration of the overloaded situation under the condition that the current system is overloaded, so that low-priority users allocate less resources for accessing The cell even prohibits low-priority users from accessing, thereby reducing the access probability of low-priority users when the current cell load is too high, and enabling high-priority users to allocate more resources for accessing the cell, ensuring It improves the access success rate of those high-priority users, and flexibly and effectively realizes the differentiated services of the mobile communication system for users with different priority levels.

In step 320, since the current cell load does not appear to be too high, the change of system parameters should be adjusted in the opposite direction to the above step 310, that is, to increase the persistence scale factor "Persistence" corresponding to the low ASC user UE. scaling factor", reduce the dynamic persistence level "Dynamic persistence level" of low-ASC users, and increase the access resources available in the UE of low-ASC users, that is, increase the available access slot "Access slot" and the available access The resource's preamble signature "Preamble signature". In this way, when the load of the current cell is not overloaded, the access resources of the low-ASC users are increased as much as possible, so that the low-ASC users can successfully access the system as much as possible. However, special attention should be paid to the fact that in this case, the high ASC standard cannot be higher than the low ASC standard, that is, the high ASC persistence scaling factor "Persistence scaling factor", access time slot "Access slot", and access resources The "Preamble Signature" of the preamble signature should be greater than or equal to the corresponding parameter of the low ASC, and the dynamic persistence level "Dynamicpersistence level" of the high ASC should be less than or equal to the corresponding parameter of the low ASC. Because, only in this way can the mobile communication system still maintain the differentiation of services for high-ASC users and low-ASC users, so that high-ASC users can always maintain higher priority access services than ordinary low-ASC users, avoiding the occurrence of After the system parameters appear, the users with the original high ASC will lose the priority of accessing the system.

Through the above-mentioned adjustments to the system parameters when the system is overloaded and not overloaded, the system can control users with different priorities to access the system under different load conditions. When the load of a cell is too high, the present invention improves the access standard of low-ASC users and limits the access of low-ASC users by adjusting system parameters. On the one hand, it effectively realizes that the mobile communication system can avoid the problem of further deterioration of the load in the case of overload, and ensures the stability of the operation of the mobile communication system; on the other hand, it can maintain the differentiated services of the mobile communication system for users with different priorities , try to ensure the access of high-priority users, and always ensure the access success rate of high-priority users.

Although the present invention has been illustrated and described with reference to certain preferred embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein, and without departing from the spirit and scope of the invention as defined by the appended claims.

Claims (6)

1. the connection control method in the mobile communication system is characterized in that, comprises following steps:

System dynamics is monitored each cell load, when cell-overload takes place, adjusts influence the system parameters that the user inserts this overloaded cells probability of success, high-grade user's the access probability of success is improved, inferior grade user's access probability of success reduction;

Described system parameters is the wireless channel access parameter that selective channel will be initiated to insert on the sub-district user will read, and comprises adhering to the scale factor parameter value, dynamically adhering to rank parameter value and access-in resource parameter.

2. the connection control method in the mobile communication system according to claim 1 is characterized in that, when cell-overload took place, the step of described system parameters adjustment comprised following substep:

What increase high-grade user adheres to the scale factor parameter value, and that reduces high-grade user dynamically adheres to the rank parameter value, increases high-grade user's access-in resource;

What reduce the inferior grade user adheres to the scale factor parameter value, and that improves the inferior grade user dynamically adheres to the rank parameter value, reduces inferior grade user's access-in resource.

3. the connection control method in the mobile communication system according to claim 1, it is characterized in that, further comprise, when the generation cell load is low, adjust influencing the system parameters that the user inserts this overloaded cells probability of success, the access probability of success the inferior grade user is not higher than under high-grade user's the access probability of success prerequisite, and inferior grade user's the access probability of success is improved, and high-grade user's the access probability of success reduces.

4. the connection control method in the mobile communication system according to claim 3 is characterized in that, the step of described system parameters adjustment comprises following substep when the generation cell load is low:

The scale factor parameter value of adhering to high-grade user is lower than adhering under the scale factor parameter value prerequisite of inferior grade user, and what increase high-grade user adheres to the scale factor parameter value, and what reduce the inferior grade user adheres to the scale factor parameter value;

The rank parameter value of dynamically adhering to high-grade user is higher than adhering under the scale factor parameter value prerequisite of inferior grade user, and that reduces high-grade user dynamically adheres to the rank parameter value, and what reduce the inferior grade user adheres to the scale factor parameter value;

Under high-grade user's the access-in resource prerequisite of access-in resource more than the inferior grade user, increase high-grade user's access-in resource, reduce inferior grade user's access-in resource.

5. the connection control method in the mobile communication system according to claim 1 is characterized in that, described access-in resource parameter comprises the preamble signature of the access slot and the access-in resource of access-in resource.

6. the connection control method in the mobile communication system according to claim 1 is characterized in that, the step that described system dynamics is monitored each cell load further comprises following substep:

Described system sends the instruction of measuring each cell load index;

The corresponding described instruction of systematic survey module responds reports measure the loading condition of described each sub-district by the requirement of this instruction after.

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