KR20060073673A - Apparatus and method for controlling flow of data in a mobile communication system - Google Patents

Abstract

The present invention relates to a method for performing control of data transmitted in a mobile communication system, and more particularly, to a method for controlling the flow of data transmitted in a mobile communication system.

The present invention provides a method for controlling the flow of data flowing from a packet data service node in a mobile communication system having a radio access network that performs packet data communication with a terminal, the packet data service node being processed in a radio access network of the mobile communication system. Determining the session to request transmission interruption according to the service priority of each session when the data is received in excess of the amount, and generating a session to request the transmission interruption as a transmission interruption request message to the packet data service node. It includes the process of delivery.

1x EV-DO, flow control, transmission interruption, transmission resume.

Description

APPARATUS AND METHOD FOR CONTROLLING FLOW OF DATA IN A MOBILE COMMUNICATION SYSTEM}             

1 is a schematic diagram of a 1x EV-DO system according to the CDMA standard;

2 is a signal flow diagram when setting the flow control according to the priority according to the preferred embodiment of the present invention;

3 is a signal flow diagram at the time of interrupting and resuming forward packet transmission according to session class according to an embodiment of the present invention;

4 is an internal block diagram of a packet control function unit according to an embodiment of the present invention;

5 is a flowchart for performing flow control of data performed in a packet control function unit according to an exemplary embodiment of the present invention.

The present invention relates to a method for performing control of data transmitted in a mobile communication system, and more particularly, to a method for controlling the flow of data transmitted in a mobile communication system.

In general, a mobile communication system is a system developed to provide a voice service while providing mobility to a user. These mobile communication systems have evolved into a form that can provide data services due to the rapid development of user needs and technology. The type of data service that can be provided in such a mobile communication system has ranged from a short short message to a step of providing a large amount of data at high speed. As such, the proportion of data services is gradually increased, and a mobile communication system of a type capable of providing only a data service in a mobile communication system has been proposed.

The mobile communication system that can provide only the data service is named as 1x EV-DO in the CDMA standardization work, and is currently accelerating commercialization. Next, the 1x EV-DO mobile communication system will be described.

In general, the 1x EV-DO mobile communication system is a system developed to transmit high-speed packet data. The 1x EV-DO mobile communication system includes a base station (ANTS) for communicating with a terminal (AT) via a wireless link, a base station controller (ANC) for controlling the base stations, and a packet control function unit (PCF) thereon. do. The base station and the base station controller are collectively called an access network (AN), and the access network and packet control function unit are collectively called a radio access network (RAN). Also, a packet data service node (PDSN) is positioned above the packet control function unit, and may communicate with an IP network or a packet data network through the packet data service node. In this configuration, communication of the data service will be described.

When a packet to be delivered to a specific terminal is input to a packet data service node, the packet data service node forwards it to a packet control function connected to its lower part. At this time, the charge is made. When the packet control function receives data to be transmitted to the specific terminal from the packet data service node, the packet control function transfers the data to the access network where the terminal is located. Accordingly, the access network delivers the received packet data to the corresponding terminal. The 1x EV-DO system, like other mobile communication systems, uses a wireless link to connect a terminal and a base station, but the remaining links are connected using a wired resource such as an E1 or T1 or an IP network.

Meanwhile, although the 1x EV-DO system was developed to provide only packet data at high speed, much effort has been made to provide a real time service such as voice service such as VoIP or PTT service to provide more various services.

On the other hand, in the 1x EV-DO system, communication can be performed only by establishing a session for each terminal or service. Therefore, as described above, the session is set up for each of the various services, and after the session is set up, data communication is performed according to the corresponding session. That is, data service is performed according to the quality of service required for each session. Therefore, if a delay occurs or is difficult to transmit data due to deterioration of a channel condition between a specific terminal and a base station, the packet control function performs packet flow control to the packet data service node accordingly. This will be described in more detail as follows. If the amount of data received from the packet data service node is greater than the amount that can be transmitted to the terminal through the base station, the packet control function performs flow control. That is, data flow control can be performed for each session.

However, in some cases, data may flow from a packet data service node in excess of the amount of data delivered to a specific access network or an amount that can be processed by a specific packet control function. As such, when more than the amount of packet data that can be processed by the packet control function is transmitted from the packet data service node, the packet control function must discard some or all of the received data. This can prevent the packet control function from becoming paralyzed and continuously out of service.

However, if the packet received by the packet control function unit is discarded in this way, a problem may occur in charging. This is because the node where charging is performed is a packet data service node. Accordingly, although the packet data service node charges data transmitted to the packet control function unit, a packet that is not actually transmitted may occur due to a problem of the packet control function unit. Then there is a problem that the user can be charged incorrectly. Therefore, in order to solve this problem, the packet control function performs flow control on packet data, and according to the current standard, only the on / off function is provided.

That is, if a packet control function cannot transmit packet data due to a problem such as a wired line or a buffer, a packet control function generates a message requesting on of flow control and transmits the message to a packet data service node. Therefore, the packet data service node stops the packet data transmission to the packet control function. In addition, the packet control function unit generates a message requesting flow control off to deliver the packet data service when the above conditions are resolved, and delivers the message to the packet data service node. The packet data service node then resumes transmission of packet data.

The message used in the above method informs the packet control function whether to use flow control for a specific session by using an A11 Registration Reply message. In general, ANC / PCF also considers flow control for each session, but controls the overall amount of forward packet inflow between each PCF and PDSN. It is also used to limit the number of sessions.However, if the total amount of forward packet inflows of the sessions in service in a particular PCF-PDSN interval exceeds a certain level and a packet loss is recognized, the flow of the link interval between PCF-PDSNs is recognized. Control can be performed. In this case, a temporary forward packet transmission stop may be requested for all sessions belonging to the interval. In the absence of consideration of the characteristics of the applications being serviced in each session or session, uniform transmission interruption causes a drop in service quality. In addition, if all sessions are allowed to be allowed to resume forward packet transmission again at a time, the likelihood of traffic congestion on the R-P link is increased again.

In this way, the 1x EV-DO system maintains service while preventing congestion of packets. However, in the system for providing various services as described above, each service requires a different quality of service. That is, there may occur a case in which a service needs to be considered in consideration of service characteristics or user grades that are not important in real-time. However, as described above, if only the simple on / off method is used, all services are blocked or transmitted, so there is a problem in that a service cannot be provided according to these characteristics. Therefore, it is necessary to control the flow of data according to each service characteristic or user's grade in the 1x EV-DO system.

Accordingly, an object of the present invention is to provide an apparatus and method for controlling the flow of data according to service characteristics in a mobile communication system.

Another object of the present invention is to provide an apparatus and method for controlling the flow of data according to a user's level in a mobile communication system.

Another object of the present invention is to provide an apparatus and method for controlling the flow of data for each session in a mobile communication system.

A method according to the present invention for achieving the above objects, as a method for controlling the flow of data flowing from a packet data service node in a mobile communication system having a radio access network that performs packet data communication with a terminal, Determining a session to request transmission interruption according to the service priority of each session when data is received in excess of the amount that can be processed in the radio access network of the mobile communication system, and transmitting the session to request transmission interruption. Generating a request message and delivering the packet to the packet data service node;

Determining the sessions that can be processed among the interrupted sessions according to priority, and generating a resume transmission message for the determined sessions to the packet data service node when the interrupted session is processed. The process may further include delivering.

The method may further include generating and transmitting a registration request message capable of performing interruption for each session from the terminal to the packet data service node when the service instance is initially set up.

An apparatus according to the present invention for achieving the above objects has a radio access network for performing packet data communication with a terminal, the radio access network is introduced from a packet data service node in a mobile communication system including a packet control function A packet control function unit for controlling the flow of data, comprising: a first control unit for controlling transmission and reception of a lower part of the radio access network and signaling, and a control of transmission and reception of a lower part of the radio access network and packet data A second control unit for controlling the packet data service node and the packet data transmission / reception, storing data received from the packet data service node, and having a buffer for detecting whether the packet data service node is stored above a predetermined threshold value. 3 a controller and the packet data service node and a packet A fourth control unit for generating and transmitting the data and transmission / reception packet and stops transmission of the signaling and the resume request message.                         

The third controller notifies the fourth controller when the data stored in the buffer is reduced to an amount that can be processed normally.

When the fourth controller receives the normal processing from the third controller, the fourth controller generates and transmits a transmission resume request message to the packet data service node.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. First of all, in adding reference numerals to the components of each drawing, it should be noted that the same reference numerals have the same reference numerals as much as possible even if displayed on different drawings.

In addition, specific details appear in the following description, which is provided to help a more general understanding of the present invention, and the present invention may be practiced without these specific matters. Will be self-evident. In the following description of the present invention, if it is determined that a detailed description of a 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 schematic diagram of a 1x EV-DO system according to the CDMA standard. Hereinafter, a 1x EV-DO system according to the CDAM standard will be described with reference to FIG. 1.

The 1x EV-DO mobile communication system is a base station (ANTS) 112, ..., 123 for communicating with a terminal (AT) 101 over a wireless link and base station controllers (ANCs) 111 for controlling the base stations. 121 and a packet control function (PCF) 130 thereon. The base station and the base station controller are collectively referred to as access networks (ANs) 110 and 120, and the access network and packet control functions are collectively referred to as radio access network (RAN) 140. Also, a packet data service node (PDSN) 150 is positioned above the packet control function unit, and may communicate with an IP network or a packet data network through the packet data service node. Detailed functional blocks of the packet control function unit 130 having the above-described configuration will be described in more detail with reference to FIG. 4 described below.

Then, a method for performing a gradual flow control by putting a differential for each session in the transmission interruption and resume operation for each session in the system having the above configuration will be described.

According to the present invention, in order to perform gradual flow control by differentially setting sessions, the PDSN 150 receives the flow control support status and rating of the terminal from an authentication server (not shown in FIG. 1) when a session of the terminal is newly established. . The PDSN 150 also transmits the session class when the flow control is transmitted to the PCF 130 for use. Therefore, when the PCF 130 performs flow control for one or more sessions later by R-P interval unit flow control, the PCF 130 proposes a procedure for selecting a session for which a forward packet transmission stop is requested according to the session class. The present invention proposes a procedure for gradually resuming forward packet transmission according to priority when ANC / PCF is determined to cancel interruption of the flow control result in units of RP intervals for one or more sessions in which forward packet transmission is interrupted. do. Through this, in R-P section flow control, it minimizes the degradation of service quality caused by uniform downlink packet transmission interruption and reduces the possibility of sudden burst of R-P section packet transmission by sequential resumption of forward packet transmission.

Therefore, the method proposed in the present invention has the following three components.

(1) Application method of session flow control according to flow control in R-P section.

(2) Stepped forward packet transmission stop request scheme according to session class.

(3) Step forward request request resumption according to session class.

Next, each of the above methods will be described with reference to the accompanying drawings. 2 is a signal flowchart when setting flow control according to priority according to an exemplary embodiment of the present invention. Hereinafter, a process of setting flow control according to priority will be described with reference to FIG. 2.

The UE 101 and the RAN 140 perform a main service instance setup procedure in step 210. This main service instance setup procedure is generally performed when the terminal establishes a session, and thus it will not be described in detail here. When the instance setup is completed as described above, the RAN 140 generates an A11 registration request message in step 220 and delivers it to the PDSN 150. In operation 230, the PDSN 150 generates an A11 Registration Reply message for the new session and transmits the A11 Registration Reply message to the RAN 140. In this case, assuming that all sessions have three grades of high, medium, and low, a corresponding session grade is included in the A11 registration response message and transmitted for each session. Therefore, PDSN 150 determines whether flow control is ON / OFF before or after receiving the A11 registration request message from the authentication (not shown in the figure, AAA: Authentication, Authorization & Access Control) server and when providing flow control. Can be configured to accept

For example, the A11 registration response message may be shown in Table 1 below.

The priority of flow control described with reference to FIG. 2 does not apply to flow control of the session itself. In addition, the priority is meaningless even when uniformly applying the operation of turning ON / OFF the forward packet transmission for all sessions. That is, the present invention is a method for handling the traffic load if it can be eliminated without uniform application. Therefore, when the RAN 140 wants to determine the actual adjustment time and the number of target sessions in order to adjust the total amount of forward packet transmission in a specific RP interval, the forward packet transmission stop / resume target according to the priority of the sessions provided with each flow control. The session and time are determined. In addition, the present invention does not deal with an algorithm on how to select a packet transmission stop / resume target session according to priority. This is because it is an internal implementation of the vendor developing the RAN, so it must be implemented for each system. However, in FIG. 4 to be described later, the components and functions thereof necessary for the PCF will be described.

In the above, only the section using A11 signaling, which is an R-P section, has been described. However, for the A10 section, the forward packet transmission stop / resume operation by the differentiated class is equally applicable to the A8 section.

Therefore, as shown in Table 2, a field indicating whether flow control of the A8 section is applied to the A9-Setup-A8 message is added.

In particular, the PCF 130 in the RAN 140 wants to temporarily suspend packet transmission due to a buffer overflow such as a MAC or channel card of the RAN 140 or an internal problem of the RAN 140 or to resume the packet later. ) May also transmit messages as shown in Tables 3 and 4, respectively.                     

When the forward packet transmission stop / resume request message of the specific session or the A8 section occurs in the A8 section, the PCF 130 determines whether to perform the same operation in the A10 section immediately. Rather than defining a new message as shown in Tables 3 and 4, it is possible to request transmission stop / resume using an existing A9-Update-A8 message. As such, when the existing message is to be used, the same effect as the present invention can be achieved by using fields that are not used or adding new fields to the existing message. An example of such a message may be illustrated in Table 5 below.

3 is a signal flow diagram of stopping and resuming forward packet transmission according to a session class according to a preferred embodiment of the present invention. Hereinafter, the signal flow at the time of stopping and resuming a forward packet according to an exemplary embodiment of the present invention will be described in detail with reference to FIG. 3.

In FIG. 3, it is assumed that the session between the terminal 101, the RAN 140, and the PDSN 150 has already been activated, that is, the session active state in step 300. That is, it is assumed that the session activation according to the present invention has been performed according to the procedure described with reference to FIG. 2.

In this case, if the packet to be transmitted to the terminal 101 is received by the PDSN 150 in step 302, the PDSN 150 transmits it to the RAN 140 in step 304. The RAN 140 then forwards the packet data back to the terminal 101 in step 306. As such, if a packet overload occurs in a specific node of the RAN 140 as shown in step 308 while transmitting packet data for the services distinguished for each session, the corresponding node stops transmitting the packet in step 310. A request message is generated and delivered to the PDSN 150 in step 312. At this time, in the packet transmission stop request message, a service stop request message is generated differently according to the level set in the session as described above. An example of such a service interruption request message may be illustrated in Table 6 below.

As shown in Table 6, the packet transmission stop request message is divided into a GRE header part, an additional attribute optional part, and a user traffic part. In the above message, a request for resumption or resumption may be set in the GRE header and forwarded to the PDSN 150. That is, when the RAN 140 decides to make a forward packet transmission stop request to the PDSN 150, the RAN 140 sets and transmits an interrupt request (XOFF) field of the GRE header. The PDSN 150 then stops packet transmission for the services of the session in which the abort request field is set.                     

Next, the method when the RAN 140 performs packet flow control will be described. If the RAN 140 decides to perform flow control for each session to adjust the forward packet inflow rate for all sessions belonging to a specific A10 interval, first, the forward packet transmission stops only for sessions having a low priority. To request. If there is still a large amount of forward packet transmission to be concerned about packet loss in a particular A10 interval, request to stop the forward transmission for the sessions having a medium priority. In addition, if necessary, it is possible to request that the forward packet transmission stop for sessions having a high priority. This case is equivalent to batch processing.

As described above, if a forward packet transmission stop request is required for all sessions regardless of priority according to an arbitrary decision of the RAN 140, the stop request message is transmitted to all sessions. Alternatively, a new A11 message may be defined and used to request forward packet transmission interruption for all sessions in a particular A10 interval.

Then, the case in which the overload state is released from the RAN 140 will be described. When the overload condition is released in the forward traffic transmission in step 316, the RAN 140 proceeds to step 318 and generates a message for requesting to resume packet transmission for the sessions for which the packet stop request message was previously set. Thereafter, the RAN 140 proceeds to step 320 and transmits a packet transmission request message to the PDSN 150. In this case, the RAN 150 may transmit a packet transmission resume request message for all transmission interruption sessions, and sessions having priority levels of high, medium, and low, as necessary. The request can be gradually resumed by forwarding the packet into three stages. As such, whether or not to resume transmission for a session whose transmission has been interrupted at once is dependent on the implementation of the RAN 140. In this case, it is also possible to define a new A11 message and request resumption of transmission for all sessions in which forward packet transmission is interrupted among sessions belonging to a specific A10 interval.

As described above, when receiving the packet transmission resumption request message, the PDSN 150 transmits the packet whose transmission has been resumed to the RAN 140 in step 322. Therefore, the RAN 140 may transmit the received packet to the corresponding terminal in step 324.

If resumption of transmission of sessions with low flow control priority is continuously delayed, the RAN randomly raises the priority step by step to check whether the resumption request is possible. If it is still determined to be impossible, the RAN can be configured to decide whether to release or still maintain the session.

4 is an internal block diagram of a packet control function unit according to an exemplary embodiment of the present invention. Hereinafter, an internal block configuration and operation of the packet control function unit according to the present invention will be described in detail with reference to FIG. 4.

The interior of the PCF can be largely divided into a part connected to the base station controller and a part connected to the PDSN. In addition, the part connected to the base station controller includes an A9 controller 411 for controlling the delivery of signaling, and an A8 controller 413 for controlling the delivery of traffic. The ASN controller 412 controls the delivery of the PDSN and the signaling and the A10 controller 420 controls the transmission of the PDSN and the traffic. Then, the above configuration will be described in detail. First, the A9 control unit 411 is connected to the AN and performs an operation for exchanging signaling according to the present invention. The signaling message to be transmitted to the higher level among the received signaling is transferred to the A11 control unit 412, and the signaling to be processed by itself is performed. In the case of A8, the A8 controller 413 transmits the traffic to the A8 control unit 413 for processing the traffic. In addition, the A11 control unit 412 performs the transmission and reception of the PDSN and signaling, and generates and delivers the messages according to the present invention described above. Accordingly, when the above problem occurs in the lower part, the A11 controller 412 generates the above-described message, generates a transmission stop or resume message of the traffic, and delivers the message to the PDSN.

In addition, the A8 controller 413 transfers the packet data transmitted from the upper level to the AN or the packet data received from the AN to the A10 controller 420. The A10 control unit 420 is divided into an A10 control unit 421 and a buffer 422 which largely control traffic, and the buffer 422 is a transmission buffer 422a that receives data to be transmitted to a terminal from the PDSN. And a reception buffer 422b for transmitting data received from the terminal to the PDSN. The transmission buffer 422a may have a threshold value according to the present invention. When the threshold value is received, the A10 controller 421 detects the data when the data is exceeded a specific threshold value. Inform this. Then, the A11 controller 421 generates the aforementioned forward packet transmission stop request message and delivers it to the PDSN. When the data is stored below the threshold value in the transmission buffer 422a, the A10 controller 421 detects this and notifies the A11 controller 412. Accordingly, the A11 controller 412 may generate the forward packet transmission resumption request message as described above and transmit it to the PDSN. Therefore, in order to prevent the ping-pong phenomenon, the threshold of the transmission buffer 422a may have a threshold value according to the stopping of transmission and a threshold value depending on the resumption of transmission. In addition, it may be configured to have a threshold value according to the upper or intermediate or lower priority of the transmitted data, respectively.

5 is a flowchart for performing flow control of data performed in a packet control function unit according to an exemplary embodiment of the present invention. Hereinafter, the flow control of data performed by the packet control function unit will be described in detail with reference to FIG. 5.

The PCF 130 checks whether the flow control is required in step 500. If the flow of the inspection result is not the required state, the flow proceeds to step 502. If the PCF 130 proceeds to step 502, the PCF 130 checks whether there is a session that has been suspended for elapsed time. If there is a transmission interrupted session in which the waiting time elapses, the process proceeds to step 504 to resume transmission of the session. In contrast, if there is no transmission interrupted session in which the waiting time elapses as a result of the check in step 502, the routine continuously checks.

On the other hand, if the flow control is required as a result of the 500 step, the flow proceeds to step 510 to check whether the flow control for each session is required. If the flow control for each session is required as a result of the check in step 510, the flow proceeds to step 512 to perform flow control for each session. Since the flow control for each session can control the flow for each session as described in the related art, it will not be described in detail here.                     

On the other hand, even if the flow control for each session is performed or not, the process may proceed to step 520. If the process proceeds to step 520 as described above, the PCF 130 checks whether transmission stop is required. As described above, if the transmission of the inspection result of step 520 is requested, the flow proceeds to step 524. However, if the transmission is not interrupted, the flow proceeds to step 522 to check whether the transmission resumes. The resumption of transmission is a case where a session in which transmission is interrupted is performed according to overall control as previously described. If resuming of the test result transmission in step 522 is required, the process proceeds to step 524. Otherwise, the routine is continuously monitored.

In this case, the process proceeds to step 524 when more data is received than the threshold of the buffer as illustrated in FIG. 4. In this case, the PCF 130 checks whether the processing for each priority can be performed. If the check result can be processed by priority, the PCF 130 proceeds to step 526 and performs transmission control according to the priority of interruption or resumption of transmission. However, if priority processing is not required, the PCF 130 proceeds to step 528 to perform the same processing for all sessions. That is, interruption or resume of transmission is performed identically for all sessions.

In the transmission control for each priority, a case where interruption of transmission is required and a case where resumption of transmission is required are determined differently according to priority. In other words, if the transmission is interrupted, the interruption is interrupted from the lower priority session. If the transmission is required to be interrupted, the interruption is restarted from the higher priority session.

As described above, interruption of all services can be prevented by controlling the flow of data in accordance with the priority of the session in the mobile communication system, and the service can be continuously maintained even if data congestion occurs for important services. There is an advantage to that.

Claims (5)

In the mobile communication system having a radio access network that performs packet data communication with a terminal, the method for controlling the flow of data flowing from a packet data service node, Determining a session to request transmission interruption according to the service priority of each session when data is received from the packet data service node in excess of the amount that can be processed in the radio access network of the mobile communication system; And generating a session to request the transmission stop as a transmission stop request message and transmitting the session to the packet data service node. The method of claim 1, Determining, according to a priority, sessions that can be processed among the interrupted sessions when the discontinued session can be processed; And generating a transmission resume message for the determined sessions and transmitting the message to the packet data service node. The method of claim 1, And generating and transmitting a registration request message capable of performing the interruption for each session to the packet data service node when an initial service instance is set up from the terminal. In the packet control function unit for controlling the flow of data flowing from the packet data service node in a mobile communication system having a radio access network for performing packet data communication with the terminal, the packet access function, A first controller for controlling transmission / reception of signaling and a lower part of the radio access network; A second controller for controlling transmission / reception of packet data and the lower part of the radio access network; A third controller which controls the packet data service node and packet data transmission / reception, stores data received from the packet data service node, and has a buffer for detecting whether the packet data service node is stored above a predetermined threshold value; And a fourth controller configured to generate and transmit a packet data service node and a packet data and signaling transmission / reception and a packet transmission stop and resume request message. The method of claim 4, wherein The third controller notifies the fourth controller when the data stored in the buffer is reduced by an amount that can be processed normally. And the fourth controller generates a transmission resume request message and delivers the message to the packet data service node when the third controller receives the normal processing from the third controller.

Images