KR20070081477A - Apparatus and method for deciding service transmission rate at call admission control - Google Patents

Abstract

An apparatus for determining service transmission rate when call admission is controlled and a method thereof are provided to control proper initial transmission rate according to whether initial transmission rate of an AMR(Adaptive Multi Rate) call is admitted via wireless resource management. An apparatus for determining service transmission rate when call admission is controlled comprises a RNC(Radio Network Controller, 110), a core network(120) and a node B(130). The RNC(110) transmits a common measurement initiation message to the node B and performs a setup for receiving a report cyclically from the node B. The node B reports transmitted carrier power and received total wideband power to the RNC at every frequency set by the RNC. The RNC converts the reported power values into radio load amount. Then, the RNC analyzes RAB(Radio Access Bearer) parameters of an RAB allocation request message received from the core network, and checks a traffic class, MBR(Max Bit Rate) and GBR(Guaranteed Bit Rate). And also the RNC analyzes parameters of an SDU(Service Data Unit) and checks a case of variable transmission rate of a set AMR call.

Description

Apparatus and method for determining service transmission rate in call admission control {APPARATUS AND METHOD FOR DECIDING SERVICE TRANSMISSION RATE AT CALL ADMISSION CONTROL}

1 is a diagram showing the configuration of a core network, a radio network control station, and a Node B for determining a service transmission rate in call admission control;

2 is a diagram illustrating a call setup process according to an AMR transmission rate between a core network, a radio network controller (RNC), a node B, and a terminal;

3 is a flowchart illustrating a call admission control process when the service rate is gradually lowered to a lower rate supported by the AMR call when the service rate is not allowed in the call admission control process.

According to the present invention, call admission control (or connection) is performed in a wideband code division multiple access (W-CDMA) system. AMR (Adaptive Multi Rate) according to Adaptive Multi Rate (hereinafter referred to as AMR) suitable for radio resource management (hereinafter also referred to as RRM) for uplink and downlink at the time of admission control). Rate) An apparatus and method for determining a service transmission rate of a call.

 Conventionally, a radio network controller (RNC) receives an assignment message from a core network (hereinafter abbreviated as CN) and receives a radio access bearer (hereinafter abbreviated as RAB) assignment message. Call Admission Control (CAC) is used only for the maximum bit rate (hereinafter abbreviated to MBR) and CNB (Guaranteed Bit Rate). The service rate of the AMR call was determined according to whether radio resource management was allowed.

 In order to determine the initial service transmission rate of an AMR call, the conventional wireless network control station has only a maximum bit rate (MRB) and a guaranteed bit rate (GBR) set by the core network during call admission control. In order to determine the initial rate of call setup, there is a problem in that it is difficult to determine the optimized rate and determine the rate that can guarantee the quality of service (QoS) of the AMR call.

 That is, when the core network (CN) sets the guaranteed bit rate (GBR) to be the same as the maximum bit rate (MBR), the radio resource management (RRM) of the radio network controller (RNC) cannot afford to accept a call to the GBR. If there is no state, it is necessary to accept the call at a low data rate due to the characteristics of the AMR call having a variable data rate. In addition, when the core network sets the lowest low data rate of the AMR call to the GBR, if the radio resource management (RRM) of the radio network controller (RNC) can set a higher data rate than the GBR, the radio network controller (RNC) In call admission control, it is necessary to determine a higher transmission rate than GBR in order to guarantee the maximum QoS. Therefore, it is necessary to determine the initial AMR transmission rate that can guarantee the maximum QoS according to the resource state of the RRM for the AMR call having a variable transmission rate in the lock access control (CAC).

  In the related art, RRM of RNC checks the type of AMR call using a database (Database) that predefines a sub flow size for each AMR call type. However, after analyzing RAB parameters, the type of AMR call is found by comparing with the sub flow size of the service data unit (SDU) format information parameter. If the sub flow size defined by the RNC is different from the sub flow size defined by the CN, the type of the AMR call cannot be found, which makes it difficult to estimate the variable data rates.

Therefore, there is a need for an apparatus and a method capable of determining an initial AMR transmission rate for guaranteeing the maximum QoS according to the resource state of an RRM for an AMR call having a variable transmission rate.

In addition, there is a need for an apparatus and a method capable of estimating a variable transmission rate of an AMR call even when the subflow size defined by the RNC as a DB and the subflow size indicated by the CN are different.

An object of the present invention is to provide an apparatus and method for determining an initial AMR transmission rate for guaranteeing the maximum QoS according to RRM resource state for an AMR call having a variable transmission rate.

Another object of the present invention is to provide an apparatus for determining an appropriate AMR service rate for RRM resources for uplink and downlink in call admission control in a W-CDMA control station (RNC) system.

The present invention also provides an apparatus capable of estimating a variable transmission rate of an AMR call even when the subflow size defined by the RNC to the database and the subflow size indicated by the CN are different. To provide a method.

In order to achieve the above object of the present invention, the present invention provides a wireless network control having the radio resource management unit for determining a service transmission rate of an adaptive multi rate (AMR) call that allows the radio resource manager for uplink and downlink in call admission control. Provides a communication system including a station.

In addition, to achieve the object of the present invention, the present invention comprises the steps of determining a service transmission rate, determining whether the radio resource management of the radio network control station allows the service transmission rate, if not the service transmission rate A process of determining a service transmission rate according to the lower transmission rate, and repeating the determination of the service transmission rate, and denying call admission control if the transmission rate is not reduced to the lower transmission rate. It provides a call admission control method.

In addition, it is possible to provide methods and apparatus of various embodiments within the scope of the present invention.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. In describing the present invention, if it is determined that the detailed description of the related known function or configuration may unnecessarily obscure the subject matter of the present invention, the detailed description thereof will be omitted.

1 is a diagram illustrating the configuration of a core network, a radio network control station, and a Node B for determining a service transmission rate in call admission control.

First, a wireless load measurement method using common measurement procedures of the radio network controller (RNC) 110 is described. The radio network control station 110 transmits a Common Measurement Initiation Message to the Node B and sets it to be periodically reported by the Node B 130. The node B 130 periodically reports the transmitted carrier power and the received total wide band power to the wireless network control station at a period set by the wireless network control station. The wireless network control station manages the power values reported from the Node B in terms of wireless load.

Next, we analyze the radio access transport (RAB) assignment request message. The radio network controller 110 may analyze the radio access transport parameters of the radio access transport (RAB) allocation request message received from the core network 120 to know the traffic class, MBR, and GBR information. In addition, it is possible to know the case of the variable transmission rate of the AMR call set by analyzing the service data unit (SDU) parameters. A summary of the radio access transport parameters and service data unit parameters in the RAB Assignment Request message is shown below.

Radio access transport parameters are classified as traffic class (conversational, streaming, interactive, background), radio access transport asymmetry indicator (RAB Asymmetry Indicator: classified as symmetric bidirectional, Asymmetric Uni directional downlink, Asymmetric Uni directional Uplink, Asymmetric Bidirectional) , Maximum Bit Rate (unit: bit / s), Guaranteed Bit Rate (unit: bit / s), and maximum service data unit size (maximum SDU Size).

Service Data Unit Parameters (SDU Parameters) are Service Data Unit (SDU) format information parameters, which contain a list of possible exact sizes of possible SDU and / or RAB subflow combination bit rates.

The AMR call with variable bit rate is defined in the 3GPP standard as follows.

For AMR-NB codec rates, the first case (12.2kbps, 7.95kbps, 5.9kbps, 4.75kbps) and the second case (10.2kbps, 6.7kbps, 5.9kbps, 4.75kbps) The fourth case (case 3) is 7.4kbps, 6.7kbps, 5.9kbps, 4.75kbps.

For AMR-WB codec rates, the first case (case 1) is 23.85 kbps, 23.05 kbps, 19.85 kbps, the second case (18.25 kbps, 15.85 kbps, 14.25 kbps, and the third case (case 3) Is 12.65 kbps, 8.85 kbps, 6.60 kbps.

Next, the AMR transmission rate is determined according to radio resource management (RRM). In call admission control (CAC), the determination of whether to accept a call basically accepts the call if it is lower than the threshold value based on Equation 1 below, which allows E1 link resource and OVSF code resource. Judge the call and accept the call. The transmission rate at this time is determined as the service transmission rate of the initial AMR call.

I _{total _old} + _Ⅰ> Ⅰ _threshold

Ⅰ은 서비스 전송률에 따른 무선 부하의 추정 값이다. 여기서 이러한 값들의 단위는 %이다. Threshold Ⅰ _threshold is a threshold value is determined by the operator operators by the radio network planning, which is set as a system parameter, I _{total _old} is the radio network controller (RNC) a target in accordance with the common measurement procedures in 3GPP (common Measurement Procedure) It is the value obtained by requesting Node B to measure the wireless load of the target cell. It is the total wireless load of the target cell. And

I is an estimated value of the wireless load according to the service rate. Where the units of these values are%.

Therefore, the radio resource management (RRM) of the radio network controller (RNC) analyzes the service data unit parameters of the radio access transport (RAB) parameters to determine the variable data rate of the AMR call. It is determined whether the radio resource management (RRM) is acceptable. If the data rate is not allowed, CAC is performed by lowering it to the lowest data rate step by step. That is, according to whether or not radio resource management is acceptable, the rate accepted between the MBR and the lowest rate is determined as the service rate of the initial AMR.

2 shows a call setup process according to an AMR rate between a core network, a radio network controller (RNC), a node B, and a terminal. Based on the set service rate, the radio network controller (RNC) 210 controls the downlink rate using a rate control frame of an up protocol to control the downlink rate. In order to notify the core network 220 of the rate information to be serviced by downlink and to control the uplink rate, only the transport format combination information of the rate to be serviced by the terminal 240 is controlled. Express it as a message and send it. Here, the Node B 230 and the terminal 240 are connected by an air interface.

Radio resource management of the radio network control station 210 analyzes the service data unit parameter of the radio access transport (RAB) allocation request message received from the core network 220 to find the type of AMR call having a variable transmission rate. Specifically, it is as follows.

First, it is checked whether the traffic class of the service data unit parameter of the radio access transport (RAB) allocation request message is conversational. Next, the number of subflows representing the AMR class (maxRABSubflows) in the RAB parameter of the radio access transport (RAB) allocation request message is checked. Next, the service data unit of the radio access transport parameter obtains the subflow service data unit size (subflowSDUSize) as many as the combination number of the RAB subflow combination (maxRABSubflowCombination) corresponding to the service data unit parameters of the number of subflows identified above. Adjust to save.

For example, subflowSDUSize [maxRABSubflowCombination] [maxRABSubflows] =

{{81,103,60}, {75,84,0}, {55,63,0}, {42,53,0}}.

Next, use the maxRABSubflows, maxRABSubflowCombination, and Subflow SDU Size information obtained above to find all the variable rates of the AMR.

(

subflowSDUSize[i,j])RABSubflowCombinationBitRates (i) =

(

subflowSDUSize [i, j])

Where RABSubflowCombinationBitRates is the sum of the bits of the subflow combination. i has a value up to maxRABSubflowCombination and j has a value of maxRABSubflows.

Next, the above-mentioned RABSubflowCombinationBitRate is converted into bits per second (bps) using a transmission unit (TTI) of a transport channel to be transmitted from a wireless network control station. In order to support the AMR service in the wireless network controller, a transmission channel having a TTI of 20 ms is used. Therefore, 50 times the RABSubflowCombinationBitRate becomes the maximum bit rate that the wireless network control station can transmit in 1000 ms, so that all the service transmission rates of the AMR call can be obtained in bps units.

  maxRABSubflowCombination

serviceRate(i) = RABSubflowCombinationBitRates(i) * 50 (단위 bps)

serviceRate (i) = RABSubflowCombinationBitRates (i) * 50 (unit bps)

The service rate obtained in the above manner is expressed as the source rate in the table below.

 RFCI (RAB Subflow Combination Indicator)  RAB subflow 1  RAB subflow 2  RAB subflow 3  Sum  Source Rate (SourceRate) RAB Subflow Combination Set       One    81    103     60  244  Source rate 1       2    42     53      0   95  Source rate 2       3    39      0      0   39  Source rate 3       0     0      0      0    0  Source rate 4

In the above table, RFCI, RAB subflow 1, RAB subflow 2, and RAB subflow 3 represent the parts transmitted in the initial procedure of the uplink and constitute a RAB subflow combination set.

Call Admission Control (i.e., radio resource management) for downlink and uplink by sorting the source speeds, which are the service rates obtained above, in descending order (high to low rates). Determines whether or not is acceptable, and selects a service transmission rate (rate) allowed by the radio resource management.

If the service rate is not allowed in the call admission control process, the service rate is lowered gradually to the lower rate that the AMR call can support. The call admission control process in this case is shown in FIG.

That is, FIG. 3 shows a call admission control process when the service rate is gradually lowered to a lower rate that the AMR call can support when the service rate is not allowed in the call admission control process.

First, the service transmission rate is determined (310). Next, it is determined whether the radio resource management allows the service transmission rate (320). If not allowed, the lowering rate is allowed (330). If the lower rate is lowered, the process of determining the service rate is repeated. If the lower rate is not lowered, call admission control is rejected (340). When the service rate determined by the radio resource management is allowed, it is determined whether the OVSF resource is allowed (350). If not allowed, the lowering rate is allowed (330). If the lower rate is lowered, the process of determining the service rate is repeated. If it allows, it is determined whether the E1 link resource is allowed (360). If not allowed, the lowering rate is allowed (330). If the lower rate is lowered, the process of determining the service rate is repeated. If it allows, it is determined whether the traffic transmission board resource is allowed (370). If not allowed, the lowering rate is allowed (330). If the lower rate is lowered, the process of determining the service rate is repeated. If it allows, the service rate is selected (380).

Thus, the service rate selected in the call admission control process for each downlink and uplink is determined as the initial service rate.

      In order to control downlink and uplink, the service rate determined in this way is used by the speed control procedure proposed in the 3GPP standard.

That is, based on the determined service rate, the radio network control station (RNC) 210 uses the rate control frame of the up protocol to control the downlink rate. In order to notify the core network 220 of the rate information to be serviced by the downlink and control the uplink transmission rate, only the transport format combination information of the rate to be served to the terminal 240 is transmitted. Expresses it as a combination control message. Here, the Node B 230 and the terminal 240 are connected by an air interface.

In the description of the present invention, radio resource management may be performed in a radio resource management unit belonging to a radio network control station.

According to the configuration of the present invention, as described above, an appropriate initial rate can be controlled according to whether radio resource management allows an initial rate of an AMR call having a variable rate. Therefore, the quality of service (QoS) of the AMR call can be guaranteed as much as possible. In addition, efficiency can be maximized in terms of systems.

Claims (7)

A communication system comprising a wireless network control station, And a radio network control station having the radio resource management unit for determining a service transmission rate of an adaptive multi rate (AMR) call that is allowed by the radio resource manager for uplink and downlink during call admission control. The method of claim 1, And said communication system is a wideband code division multiple access communication system. The method of claim 1, The wireless network control station transmits a common measurement start message to the node B, receives a constant power value from the node B every period set by the wireless network control station, and converts the wireless load into a wireless network control station. Communication system comprising a. The method of claim 1, The wireless network controller notifies the core network of transmission rate information to be serviced by downlink, and transmits transmission format combination information of a rate to be serviced to a terminal in a transmission format combination control message to control the uplink transmission rate. A communication system comprising a wireless network control station. A call admission control method of a communication system including a wireless network control station, Determining a service rate; Determining whether radio resource management of the radio network control station allows the service transmission rate; If not allowed, the wireless network includes downgrading the service rate to an allowable lower rate, repeating the process of determining the service rate accordingly, and rejecting call admission control if the service rate is not lowered. Call admission control method of a communication system including a control station. The method of claim 5, Determining whether to allow OVSF resources when the radio resource management allows the service transmission rate; Determining whether to allow the E1 link resource if the OVSF resource allows it; Determining whether to allow traffic transmission board resources when E1 allows; And selecting the service transmission rate when the traffic transmission board resource permits. The method of claim 6, When the OVSF resource does not allow or when the E1 link resource does not allow or when the traffic transmission board resource does not allow, the service rate is lowered to a lower rate, and again, the service rate is determined accordingly. Repeating the procedure, and if failing to lower the lower transmission rate, rejecting call admission control.

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