KR20080105276A - System and method for scheduling data traffic in a communication system - Google Patents

Abstract

A system and a method for scheduling data traffic in a communication system are provided to offer a qualified communication service to a user by suggesting a scheduling algorithm using a border boundary function. A data scheduling method comprises the steps of: judging whether or not data are provided in real-time; in case that the data are provided in real-time, comparing service delay time of the data with a predetermined border delay value(205); and scheduling the data when the predetermined border delay value is larger than the service delay time(217).

Description

System and method for scheduling data traffic in communication system {SYSTEM AND METHOD FOR SCHEDULING DATA TRAFFIC IN A COMMUNICATION SYSTEM}

1 is a diagram illustrating a boundary delay function proposed by a communication system according to an exemplary embodiment of the present invention.

2 is a diagram illustrating a process of scheduling by a scheduler in a communication system according to an exemplary embodiment of the present invention.

3 is a diagram illustrating an operation example of a jump algorithm in a communication system according to an exemplary embodiment of the present invention.

The present invention relates to a communication system, and more particularly, to a data traffic scheduling system and method in a communication system.

In general, active researches are being conducted to provide users with services having high quality of service (QoS: Quality of Service, hereinafter referred to as 'QoS') in a next generation communication system. In particular, the next generation communication system supports high-speed services in the form of ensuring mobility and QoS of a plurality of mobile stations (MSs).

In this next-generation communication system, a receiver, such as a terminal, is a communication service having various QoS from a transmitter, such as a base station (BS), for example, an Unsolicited Granted Service (UGS) type. A real time polling service (rtPS) type, a non real time polling service (nrtPS) type, Communication service such as Best Effort (BE) service type is provided.

Meanwhile, in order to provide communication services such as UGS type, rtPS type, nrtPS type, and BE type, the next-generation communication system has various QoS to the user, the base station performs scheduling and transmits data to the terminal adaptively. shall.

However, in the current next generation communication system, a specific method for providing a communication service for guaranteeing QoS of a user has not been proposed. In particular, as described above, a method for adaptively providing a communication service having various QoS to a user is needed. In other words, there is a need for a scheduling scheme for adaptively providing data of the various service types.

Accordingly, the present invention proposes a system and method for adaptively scheduling data traffic in a communication system.

In addition, the present invention proposes a data traffic scheduling system and method for providing a communication service having various QoS in a communication system.

Hereinafter, the operation principle of the preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings. In addition, in describing the present invention, when 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. Terms to be described later are terms defined in consideration of functions in the present invention, and may be changed according to intentions or customs of users or operators. Therefore, the definition should be made based on the contents throughout the specification.

The present invention proposes a system and method for adaptively scheduling data traffic in a communication system.

In an embodiment of the present invention to be described below, a best effort (BE) that considers data traffic and a throughput of a voice over Internet Protocol (VoIP) type sensitive to a maximum allowable delay time such as a voice service, that is, a real time delay, is preferred. A method of adaptively scheduling data traffic of type Best Effort (hereinafter, referred to as 'BE') will be described.

First, a communication system according to an embodiment of the present invention will be described on the assumption that BE type data traffic and VoIP type data traffic are scheduled by one scheduler of the base station MAC layer.

On the other hand, the scheduler for scheduling the typical BE-type data traffic uses a proportional fair (hereinafter, referred to as PF) algorithm. The PF algorithm uses a ratio of average throughput parameters for fairness between the current user's channel situation and the user. That is, the PF scheduler selects the user having the largest value among the metrics output through the scheduling algorithm proposed by Equation 1 to provide a communication service to maximize the overall throughput.

은 i번째 사용자의 n 번째 전송 시점의 채널 상황에서 제공 가능한 전송 레이트를 의미하며, 상기

은 저역 통과 필터링 된 사용자의 평균 처리량을 의미한다. 즉, 상기 i번째 사용자의 n번째 전송 시점의 채널 상황에서 제공 가능한 전송 레이트에서 저역 통과 필터링 된 사용자의 평균 처리량을 나눈 값 중 가장 큰 값을 가지는 사용자를 선택한다.Where above

Denotes a transmission rate that can be provided in a channel situation of an nth transmission time point of an i-th user.

Means the average throughput of lowpass filtered users. That is, the user having the largest value among the values obtained by dividing the average throughput of the low pass filtered user by the transmission rate that can be provided in the channel situation at the nth transmission time of the i th user is selected.

However, the scheduler using the scheduling algorithm as shown in Equation 1 does not satisfy the QoS of the data traffic of the VoIP type. Therefore, the scheduler proposes a scheduling algorithm such as Equation 2 below reflecting the time delay factor.

는 n번째 전송 시점에 i번째 사용자에 대해 버퍼가 스케줄링 해야 할 VoIP 타입의 데이터 트래픽의 데이터 양을 나타내며, 상기

는 n번째 전송 시점에서 스케줄러에 허용된 최대 허용 지연 시간까지 남은 시간을 나타낸다. 또한

와

은 서로 같거나 또는 상이한 시스템의 가중치를 나타낸다. 일 예로 BE 타입의 데이터 트래픽의 경우 가중치 값은 0으로 설정할 수 있다. 상기 수학식 2에서 제안한 스케줄링 알고리즘을 이용하여 상기 스케줄러는 처리 지연이 오래된 순서대로 VoIP 타입의 데이터 트래픽을 우선적으로 선택하여 스케줄링 한다.Where above

Denotes the amount of data of VoIP type data traffic that the buffer should schedule for the i th user at the n th transmission time point.

Represents the time remaining from the nth transmission time to the maximum allowable delay time allowed for the scheduler. Also

Wow

Denote weights of the same or different systems. For example, in the case of the BE type data traffic, the weight value may be set to 0. Using the scheduling algorithm proposed in Equation 2, the scheduler preferentially selects and schedules the VoIP type data traffic in the order of the longest processing delay.

However, the scheduler using the scheduling algorithm proposed in Equation 2 is not always efficient. In other words, a case in which the output metric value of the BE type data traffic is greater than the output metric value of the VoIP type communication service may be output so that the BE type data traffic is scheduled first. Accordingly, the QoS of the communication service providing the VoIP type data traffic is affected. Therefore, a scheduling algorithm as shown in Equation 3 is proposed in a communication system in which BE type data traffic and VoIP type data traffic are mixed.

는 i번째 사용자의 스케줄링 우선순위(priority)를 나타낸다. 상기

는 VoIP 타입의 데이터 트래픽의 경우 가장 큰 값을 갖는다. 또한

는 가중치를 나타낸다. Where above

Represents the scheduling priority of the i-th user. remind

Has the largest value for data traffic of VoIP type. Also

Denotes a weight.

Scheduling through the scheduling algorithm proposed by Equation 3 is more efficient than the algorithm of Equation 2. However, when high priority data traffic such as the VoIP type is present, the probability of BE type data traffic having a relatively low priority value being scheduled becomes low. Therefore, scheduling through the scheduling algorithm proposed in Equation 3 affects the QoS of the communication service providing the BE type data traffic.

Accordingly, when the BE type data traffic and the VoIP type data traffic are mixed in a communication system, Equation 4 is used to adaptively schedule the BE type data traffic and the VoIP type data traffic. We propose a scheduling algorithm.

를 나타내며, BE 타입의 데이터 트래픽의 경우,

이다. Where

For BE type data traffic,

to be.

은 경계 지연 함수를 나타낸다. 한편, 상기 BE 타입의 데이터 트래픽은

이며, 상기 BE 타입의 데이터 트래픽은 본 발명에서 제안하는 경계 지연 함수에 의해 적응적으로 스케줄링 된다. Also

Denotes a boundary delay function. Meanwhile, the BE type data traffic

The BE type data traffic is adaptively scheduled by the boundary delay function proposed in the present invention.

That is, the boundary delay value of the boundary delay function is adaptively changed to the channel environment of each user to increase the transmission efficiency of the BE type data traffic.

Next, a conceptual diagram of the boundary delay function proposed by the communication system according to an exemplary embodiment of the present invention will be described with reference to FIG. 1.

1 is a diagram illustrating a boundary delay function proposed by a communication system according to an exemplary embodiment of the present invention.

(101)을 갖는다. 상기

값(101) 이전에는

이므로, 스케줄러는 VoIP 타입의 데이터 트래픽을 스케줄링 하지 않는다. 즉, 상기

값(101) 이전에는 BE 타입의 데이터 트래픽을 선택하여 스케줄링을 수행한다. 또한 상기

값(101) 이후에는 우선 순위가 높은 VoIP 타입의 데이터 트래픽을 선택하여 스케줄링을 수행한다.Referring to FIG. 1, the boundary delay function is a boundary delay value.

Has 101. remind

Before the value (101)

Therefore, the scheduler does not schedule data traffic of VoIP type. That is

Before the value 101, the BE type data traffic is selected to perform scheduling. Also above

After the value 101, scheduling is performed by selecting data traffic of a high priority VoIP type.

Next, a process of scheduling by a scheduler in a communication system according to an exemplary embodiment of the present invention will be described with reference to FIG. 2.

2 is a diagram illustrating a process of scheduling by a scheduler in a communication system according to an exemplary embodiment of the present invention.

Referring to FIG. 2, in step 201, the scheduler checks a user index and proceeds to step 203. In step 203, the scheduler determines whether there is data type of VoIP type to be provided to the user. As a result of the determination, if there is the VoIP type data traffic, the process proceeds to step 205, and if there is no VoIP type data traffic, the process proceeds to step 211.

을 이용하여 메트릭 값을 출력하고 213단계로 진행한다.If there is no VoIP type data traffic to be provided to the user, i.e., BE type data traffic exists, the process proceeds to step 211.

And outputs the metric value using step 213.

을 선택, 즉, 상기 VoIP 타입의 데이터 트래픽을 선택하고 211단계로 진행한다. 상기 211단계에서 상기 스케줄러는

을 이용하여 메트릭 값을 출력하고 213단계로 진행한다.On the other hand, if there is a VoIP type data traffic to be provided to the user, the scheduler proceeds to step 205 and the boundary delay value of the boundary delay function is the maximum service delay time for which the VoIP type data traffic should be provided, that is, the It is determined whether the maximum time that the VoIP type data traffic should be provided is greater than the remaining time. If the boundary delay value of the boundary delay function is greater than the service delay time, the scheduler proceeds to step 207.

Ie, select the VoIP type data traffic and proceed to step 211. The scheduler in step 211

And outputs the metric value using step 213.

을 선택, 즉, 상기 VoIP 타입의 데이터 트래픽을 선택하지 못하고, 즉, 상기 VoIP 타입의 데이터 트래픽을 폐기하고211단계로 진행한다. 상기 211단계에서 상기 스케줄러는

을 이용하여 메트릭 값을 출력하고 213단계로 진행한다. 이 때, 상기 스케줄러는

을 삽입하여 계산하므로, 상기

는 '0'이 되어 스케줄링을 수행하지 못하게 된다.If the boundary delay value of the boundary delay function is smaller than the service delay time, the scheduler proceeds to step 209.

Select, ie, fail to select the VoIP type data traffic, that is, discard the VoIP type data traffic and proceed to step 211. The scheduler in step 211

And outputs the metric value using step 213. At this time, the scheduler is

Is calculated by inserting

Becomes '0' to prevent scheduling.

In step 213, the scheduler checks whether another user exists, and if another user exists, proceeds to step 203 through step 215, and proceeds to step 217 if another user does not exist. The scheduling is performed according to the metric value and the process ends.

On the other hand, the boundary delay value of the boundary delay function has a different value corresponding to the access channel environment of the user receiving the VoIP type data traffic. For example, when the environment of the channel accessed by the user is good, the boundary delay value has a relatively high value, and when the environment of the channel accessed by the user is poor, the boundary delay value has a relatively low value.

As described above, the boundary delay value of the boundary delay function is adaptively changed according to the access channel environment of the user. The process of changing the boundary delay value corresponding to the access channel environment of the user is performed by an algorithm shown in Equation 5 below.

은 i번째 VoIP 타입의 데이터 트래픽의 n번째 전송 시점에서의 경계 지연 값을 나타낸다. 또한 상기

는 적응형 단계를 나타내며, 본 발명의 통신 시스템에 의해 미리 설정된 스텝 사이즈(Step-Size)와 QoS 에 따른 목표 에러율을 나타내는 타겟 블록 오류율(BLER)에 의해 구성된다. 즉, 상기

은 하기 수학식 6과 같이 나타낼 수 있다.Where above

Denotes a boundary delay value at the nth transmission time point of the i-th VoIP type data traffic. Also above

Denotes an adaptive step, and is constituted by a target block error rate (BLER) indicating a step size and a target error rate according to QoS preset by the communication system of the present invention. That is

Can be expressed as in Equation 6 below.

In the present invention, the step size is 1, and the target error rate of the data traffic of the VoIP type is 2%. The target BLER also has a value of 0.02.

On the other hand, it is assumed that the base station includes an error detection device. At this time, the error detection apparatus in the base station performs a cyclic redundancy check (CRC: cyclic redundancy check, hereinafter referred to as 'CRC') of the VoIP type data traffic at the nth transmission time point, whether a CRC error has occurred. Check it. In addition, when an error occurs in the VoIP type data traffic due to service delay in the base station, the boundary delay value of the boundary delay function is updated to a preset initial boundary delay value. On the other hand, when the CRC error does not occur or the VoIP type data traffic does not generate an error, the boundary delay value of the boundary delay function is changed through Equation 6.

Next, an operation example of a jump algorithm performed by Equation 5 in a communication system according to an embodiment of the present invention will be described with reference to FIG. 3.

3 is a diagram illustrating an operation example of a jump algorithm in a communication system according to an exemplary embodiment of the present invention.

Referring to Figure 3, the base station checks the error due to the CRC error or service delay of the data traffic of the VoIP type in the error detection device in the base station. If an error does not occur in the VoIP type data traffic as a result of the error checking, the threshold delay value according to the service delay time to be performed by the scheduler is increased (301). In this case, the boundary delay value may be increased only up to a preset maximum delay boundary value.

If an error occurs as a result of the error checking (303), the boundary delay value according to the service delay time is initialized to an initial boundary delay value. In addition, after initializing the initial boundary delay value and performing error check again, if no error occurs as a result of the error check, the threshold delay value according to the service delay time to be performed by the scheduler is increased (305).

Meanwhile, in the detailed description of the present invention, specific embodiments have been described, but various modifications may be made without departing from the scope of the present invention. Therefore, the scope of the present invention should not be limited to the described embodiments, but should be determined not only by the scope of the following claims, but also by the equivalents of the claims.

As described above, the present invention proposes a scheduling algorithm using a boundary delay function to adaptively provide a communication service having various quality of service in a communication system, thereby providing a communication service corresponding to a desired quality of service. There is an advantage.

Claims (14)

In the data scheduling method in a communication system, Determining whether the data is a data providing a real time service or a data providing a non real time service; As a result of the determination, when the data is data providing a real-time service, comparing the service delay time of the data with a preset boundary delay value; And scheduling the data when the preset boundary delay value is large as a result of the comparison. The method of claim 1, And discarding the data when the preset boundary delay value is small as a result of the comparison. The method of claim 2, The boundary delay value is, And a value determined according to an access channel environment of a user who wants to receive high quality data. The method of claim 1, And if the data is data providing a non-real-time service as a result of the determination, scheduling the data. The method of claim 4, wherein And the data providing the non-real-time service is data of a best effort type. The method of claim 1, And data providing the real time service is a voice service. The method of claim 1, Scheduling the data, Equation

Data scheduling method, characterized in that for scheduling data through. remind

Denotes the scheduling priority of the i-th user,

Represents a weight, and

Is

And said

Denotes a transmission rate that can be provided in a channel situation of an nth transmission point of an i-th user.

Represents your average throughput,

Represents the amount of data of the real-time service type for which the buffer should be scheduled for the i-th user at the nth transmission time.

Represents the remaining time until the maximum allowable delay time allowed for the scheduler at the nth transmission time point.

Denotes the boundary delay function. In a data scheduling system in a communication system, It is determined whether the data is a data providing a real time service or a data providing a non-real time service. If the data is data providing a real time service, the service delay time and a preset boundary delay value of the data are determined. And a scheduler for scheduling the data when the preset boundary delay value is large as a result of the comparison. The method of claim 8, The scheduler, And discarding the data when the preset boundary delay value is small as a result of the comparison. The method of claim 9, The boundary delay value is, And a value determined according to an access channel environment of a user who wants to receive high quality data. The method of claim 8, The scheduler, And if the data is data providing a non-real-time service as a result of the determination, scheduling the data. The method of claim 11, And the data providing the non-real time service is data of a best effort type. The method of claim 8, And data providing the real time service is a voice service. The method of claim 8, The scheduler, Equation

Data scheduling system, characterized in that for scheduling data through. remind

Denotes the scheduling priority of the i-th user,

Represents a weight, and

Is

And said

Denotes a transmission rate that can be provided in a channel situation of an nth transmission point of an i-th user.

Represents your average throughput,

Represents the amount of data of the real-time service type for which the buffer should be scheduled for the i-th user at the nth transmission time.

Represents the remaining time until the maximum allowable delay time allowed for the scheduler at the nth transmission time point.

Denotes the boundary delay function.

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