CN1968522A - Method for interface call admission control in communication system - Google Patents

Abstract

The invention provides a method for controlling access to interface calls in a communication system. The method includes steps: a user sends a service request to the communication system, requesting access to the communication system to perform its business; after receiving the request, the communication system accesses the Calculate the interface bandwidth that will be occupied after accessing the service requested by the user based on the activation factor corresponding to the service requested by the user; when the occupied interface bandwidth will exceed the maximum transmission bandwidth of the interface after accessing the service requested by the user, the user is prohibited from accessing On the contrary, it is allowed to access the user's business. In the present invention, by setting different activation factors for different services and using the activation factors to calculate the control bandwidth of interface access, the utilization efficiency of interface transmission bandwidth can be improved and network operation and maintenance costs can be saved.

Description

Interface Call Admission Control Method in Communication System

technical field

The invention relates to a call admission control method for an interface, in particular to an interface call admission control method in a communication system.

Background technique

The radio access part (UTRAN) of the WCDMA system is composed of multiple radio network subsystems (RNS), and each RNS includes a radio network controller (RNC) and one or more node Bs (NodeB). Inside the RNS, the Node B and the RNC are connected through the Iub interface, and the RNC and the RNC are connected through the Iur interface, and the Node B communicates with the user equipment (UE) through the air interface.

Because the Iub interface transmission bandwidth resources between RNC and Node B in the WCDMA system are limited, therefore, the transmission bandwidth consumed by Iub interface traffic generally cannot exceed the maximum transmission bandwidth resource that can be provided by physics. When the total transmission bandwidth resources consumed by new users and previous users exceed the maximum transmission bandwidth resources that can be physically provided, the RNC will prohibit new users from accessing through an admission control algorithm.

In the WCDMA system, the Iub interface generally adopts ATM Adaptation Layer 2 (ATM AdaptationLayer 2, AAL2), and the bandwidth mentioned here refers to the AAL2 bandwidth.

Figure 1 shows the flowchart of call admission control in WCDMA system. The control process is specifically as follows: first, in step 100, the user sends a service request to the WCDMA system, requesting access to the WCDMA system to perform its service; The AAL2 bandwidth of the Iub interface (step 101), and then calculate whether the occupied AAL2 bandwidth will exceed the maximum transmission bandwidth of the Iub interface (step 102) after accessing the user service. When the judged result is that the occupied AAL2 bandwidth after accessing the user's business can exceed the maximum transmission bandwidth of the Iub interface (yes), the business (step 103) of the user's access is prohibited; otherwise, when the judged result is connected to the When the AAL2 bandwidth occupied by the user service will not exceed the maximum transmission bandwidth of the Iub interface (no), the user service is allowed to be accessed (step 104).

The starting point of the prior art is to ensure that the Iub transmission bandwidth is not congested, that is, the maximum bandwidth occupied by users of the Iub interface will not exceed the maximum transmission bandwidth of the Iub interface under any circumstances. Therefore, each service uses the full rate as the admission control basis, that is, in the process of calculating the occupied AAL2 bandwidth after the service is accessed, it is considered that all currently accessed services occupy the bandwidth at the full rate.

Taking the physical layer of Iub transmission to configure only one E1 standard transmission interface as an example, the maximum value of its AAL2 channel bandwidth is 1760k, and it is assumed that there are only two kinds of services in the system, adaptive multi-rate (AMR) voice service and packet domain (PS ) 384k business. In this case, according to the prior art, the total AAL2 bandwidth consumption calculation formula is as follows:

Total AAL2 bandwidth consumption = M × AAL2 bandwidth occupied by full-rate PS 384k services + N × AAL2 bandwidth occupied by full-rate AMR voice services Formula (1)

Among them, M is the number of full-rate PS 384k services accessed, and N is the number of full-rate AMR voice services 12.2K accessed.

Here, it should be pointed out that in practical applications, in order to improve transmission efficiency, the data transmitted on the E1 standard transmission interface needs to be encapsulated according to the FP/AAL2 protocol, which will increase additional overhead. The AAL2 bandwidth occupied by the service can be calculated according to the format encapsulated by the FP/AAL2 protocol and the actual bandwidth of the service. For example, a PS 384k service with a full rate bandwidth of 384kbps will occupy an AAL2 bandwidth of 553kbps at a full rate, and an AMR voice service with a full rate bandwidth of 12.2kbps will occupy an AAL2 bandwidth of 23.4kbps at a full rate. Therefore, in the calculation of the total AAL2 bandwidth occupation, the AAL2 bandwidth occupied by each service at full rate is used. Since the AAL2 channel bandwidth is at most 1760k, the total AAL2 bandwidth consumption must be less than 1760k.

Therefore, if the number of PS 384k services using the AAL2 bandwidth of the Iub interface is M, and the number of AMR voice services is N, and assuming that a user requests to access a new AMR voice service, the system calculates according to formula (1) The AAL2 bandwidth occupied by M full-rate 384k services and (N+1) full-rate AMR voice services is taken as the total AAL2 bandwidth consumption, and it is judged whether this value is greater than the maximum AAL2 channel bandwidth, which is 1760k.

If the judgment result shows that the AAL2 bandwidth occupied after accessing the user's service will exceed the maximum AAL2 channel bandwidth of 1760k, then the access to the user's AMR voice service is prohibited; When the occupied AAL2 bandwidth will not exceed the maximum AAL2 channel bandwidth of 1760k, the user service is allowed to be accessed.

In this way, it can be ensured that the total consumption of the AAL2 bandwidth does not exceed the maximum transmission bandwidth resource that can be physically provided, so that transmission bandwidth congestion does not occur.

However, in actual situations, the bandwidth actually occupied by each service, such as AMR voice, circuit domain (CS) data, PS data service, etc., is distributed with a certain probability. It can be considered that the actual occupied bandwidth of each service has an activation factor relative to the full-rate transmission, and the activation factor reflects the probability of the full-rate data transmission of the service, and this probability is generally less than 1. Therefore calculate the occupied total bandwidth as the standard of admission control with the occupied bandwidth of various services at full speed, although it has ensured that the Iub transmission bandwidth is not congested, there is a large waste of transmission bandwidth resources.

Contents of the invention

The purpose of the present invention is to propose a method for controlling interface call admission in a communication system, so as to overcome the problem of waste of transmission bandwidth resources in the prior art.

In order to achieve the above object, the interface call admission control method in the communication system provided by the present invention comprises the following steps:

Step 100, the user sends a service request to the communication system, requesting access to the communication system to perform its service;

Step 101, after receiving the request, the communication system calculates the interface bandwidth that will be occupied after accessing the service requested by the user according to the activation factor corresponding to the requested service;

Step 102, when the occupied interface bandwidth will exceed the maximum transmission bandwidth of the interface after accessing the service requested by the user, prohibit access to the user's service, otherwise, allow access to the user's service.

Wherein, the communication system is a WCDMA system, and the interface is an Iub interface. The service requested for access is at least one of AMR voice service, CS data service and PS data service.

Compared with the prior art, the beneficial effect of the present invention is that by setting different activation factors for different services and using the activation factors to calculate the control bandwidth of interface access, the utilization efficiency of interface transmission bandwidth can be improved, and network operation and maintenance costs can be saved. .

Description of drawings

FIG. 1 is a flowchart of a call admission control process in an existing WCDMA system.

Fig. 2 is a flow chart of the call admission control process in the WCDMA system of the present invention.

Detailed ways

The transmission bandwidth resources of the Iub interface between the RNC and the Node B of the WCDMA system are very limited. In the prior art, the occupied bandwidth is used to calculate the occupied total bandwidth as the admission control standard based on the occupied bandwidth of various services. Although the Iub transmission bandwidth is guaranteed No congestion, but there is a large waste of transmission bandwidth resources.

In order to improve the utilization efficiency of Iub transmission bandwidth and save network operation and maintenance costs, the present invention sets different activation factors respectively for different services (such as AMR service, PS 384k, etc.), that is, the probability of reaching full rate bandwidth occupation is calculated as the Iub interface standard Enter the standard control bandwidth.

The call admission control method according to the present invention is shown in FIG. 2 . The specific process is as follows: first, in step 200, the user sends a service request to the WCDMA system, requesting access to the WCDMA system to execute its service; The AAL2 bandwidth (step 201) of the Iub interface that will be taken after the service of request, and then calculate whether the AAL2 bandwidth that takes after inserting this user service can exceed the maximum transmission bandwidth of the Iub interface (step 202). When the judged result is that the AAL2 bandwidth taken after accessing the user's business can exceed the maximum transmission bandwidth of the Iub interface (yes), the business (step 203) of the user's access is prohibited; otherwise, when the judged result is connected to the When the AAL2 bandwidth occupied by the user service will not exceed the maximum transmission bandwidth of the Iub interface (no), the user service is allowed to be accessed (step 204).

It can be seen that the call admission control method of the present invention is basically the same as the method in the prior art shown in the flowchart of FIG. 1 . The only difference is that in the present invention, in the calculation of bandwidth occupancy in step 201, an activation factor is set for each type of business, indicating the probability that this type of business reaches full rate during transmission, and it is assumed that during transmission , the bandwidth occupied by each service is the product of its full rate AAL2 bandwidth and the corresponding activation factor. This is different from calculating the total occupied AAL2 bandwidth in step 101 of the flow chart of FIG. 1 by using the full-rate AAL2 bandwidth occupied by each service.

For the purpose of illustration, the call admission control method according to the present invention is illustrated by taking the system to only allow access to the two services of AMR voice service and PS 384k service. And assume that the AAL2 activation factor of the AMR voice service is p, that is, assume that the actual bandwidth occupied by each AMR voice service in the actual transmission process is the full rate bandwidth (AMR Alloc BW) 23.4kbps×p; the activation factor of the PS 384K service is q, that is, the actual During the transmission process, the actual bandwidth occupied by each PS 384K service is the full rate bandwidth of 533kbps(PS data Alloc BW)×q. Among them, the values of p and q are between 0 and 1.

Therefore, when there are M PS 384K data services and N AMR voice services being transmitted on the Iub interface, according to the above assumptions, the total transmission bandwidth (AAL2 Total Addmission BW) currently occupied by all service admission control is:

Total AAL2 bandwidth consumption = M × AAL2 bandwidth occupied by full-rate PS 384k services × q+N × AAL2 bandwidth occupied by full-rate AMR voice services × p Formula (2)

Generally speaking, parameters p and q can be determined according to actual network operation. For example, the probability of simultaneous full rate data transmission of multiple PS 384K services is small, r can be 0.5, the probability of AMR voice full rate is medium, p can be a small value such as 0.7, and so on.

Therefore, according to the call admission control method of the present invention, if the number of PS data services currently using the AAL2 bandwidth of the Iub interface is M, the number of AMR voice services is N. And assume that in step 200 there is a user request to insert a new AMR voice service, then the system calculates the AAL2 bandwidth taken by M PS data services and (N+1) AMR voice services according to formula (2) as total AAL2 bandwidth consumption ( Step 201), and judge whether the value is greater than the maximum AAL2 channel bandwidth of 1760k (step 202).

If the AAL2 bandwidth occupied after the judgment result shows that accessing the user service can exceed the maximum value of the AAL2 channel bandwidth when it is 1760k (yes), the AMR voice service (step 203) of the user is forbidden to access the user; otherwise, when the judgment result shows that the AAL2 channel bandwidth is connected When the AAL2 bandwidth occupied after entering the user service will not exceed the AAL2 channel bandwidth maximum value of 1760k (No), allow access to the user service (step 204).

After determining an initial parameter p, q value, the operator needs to monitor the actual blocking probability of the network Iub interface transmission bandwidth. If the blocking probability is relatively high, it is necessary to modify the value of the parameter p, q in time, so as to save the Iub transmission bandwidth and save the Iub transmission bandwidth. Congestion control is aimed at as low a level as possible.

For example, using the full-rate bandwidth scheme of the existing technology, for the maximum AAL2 channel bandwidth of 1760k, it is allowed to simultaneously access three 384k PS 384k services and four 12.2k AMR voice services, or three 384k PS 384k business and four 12.2k AMR voice services.

And adopt the activation factor bandwidth scheme of the present invention, under the situation of q=0.5; p=0.7, can allow to insert the PS 384k service of 6 384k at most and the AMR voice service of 6 12.2k, or the PS of 4 384k 384k business and 40 12.2k AMR voice services; or 3 384k PS 384k services and 56 12.2k AMR voice services.

According to the present invention, the Iub transmission bandwidth can be saved, that is, the same Iub transmission bandwidth can allow more users to be connected, and the caused Iub blocking is still within the acceptable range of an operator.

Above, for the purpose of illustration, the call admission control method of the present invention is illustrated by taking the two situations that the system only allows access to the PS 384K data service and the AMR voice service as examples. It should be understood that for the situation where multiple services exist in the system at the same time, the idea of the present invention can be similarly applied, and different activation factors are set according to the probability of bandwidth occupied by different services at full rates to calculate the Iub interface admission control bandwidth.

The above is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed in the present invention can easily think of changes or Replacement should be covered within the protection scope of the present invention. Therefore, the protection scope of the present invention should be determined by the protection scope of the claims.

Claims (4)

1. method for interface call admission control in the communication system is characterized in that, may further comprise the steps:

Step 100, the user sends service request to communication system, and the request access communication system is carried out its business;

Step 101, communication system are after the request of receiving, and the professional corresponding activity factor that inserts by request calculates the interface bandwidth that will take after the business that inserts user's request;

Step 102 when whether shared interface bandwidth after the business that is inserting user's request can surpass the maximum transmission bandwidth of interface, forbids inserting this user's business, otherwise, allow to insert this customer service.

2. the method for claim 1 is characterized in that, described communication system is the WCDMA system.

3. method as claimed in claim 2 is characterized in that, described interface is an Iub interface.

4. require 1 to 3 each described method as profit, it is characterized in that, the business that request inserts is at least a business in AMR voice service, CS data service and the PS data service business.

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