KR101948412B1 - Method and system for packet scheduling to guarantee the short-term delay and long-term fairness in lte environment - Google Patents

Abstract

A packet scheduling method and system for guaranteeing short-term delay and long-term fairness in an LTE environment is disclosed. A packet scheduling method in a wireless communication network, the method comprising: monitoring a data flow of a user terminal using a DSE (Deficit Surplus Estimator); and determining a quantum value of a DRR (Deficit Round Robin) And a step of adjusting.

Description

TECHNICAL FIELD [0001] The present invention relates to a packet scheduling method and system for guaranteeing a short-term delay and a long-term fairness in an LTE environment,

The following description relates to a packet scheduling technique for guaranteeing a short term delay and a long term fairness in an LTE (Long Term Evolution) environment.

In the LTE system, a connection is established between a user terminal (that is, an electronic device such as a smart phone carried by a user) and an evolved packet system (EPS) through a bearer. The bearer includes a default bearer and a dedicated bearer. The default bearer is a basic bearer that is created when a user terminal accesses an LTE network, and a dedicated bearer represents a bearer that is additionally generated to receive QoS (Quality of Service). Here, the default bearer is always set to Non-GBR (Guaranteed Bit Rate) traffic, and the dedicated bearer is configured to support Guaranteed Bit Rate (GBR) traffic or Non-GBR .

User traffic IP flows of the PDN (Packet Data Network) are mapped to SDF (Service Data Flow) in the P-GW (Packet Gateway) of the LTE network. Here, SDF is a unit for applying QoS rules. User data transmission in an LTE network is performed through a physical channel, and the physical channel may include a PDSCH (Physical Downlink Shared Channel). That is, as indicated by the PDSCH name, user terminals belonging to an LTE cell included in the LTE network share the physical channel. Generally, LTE networks do not use resource reservation scheme.

Accordingly, there is a need for a packet scheduling technique in a radio physical channel between an eNB and a user terminal to guarantee a QoS parameter set in a bearer and an SDF (Service Data Flow).

[1 ] R. Kwan , C. Leung , and J. Zhang , Proportional Fair Multiuser Scheduling in LTE , IEEE Signal Processing Letters, Vol. 16, 461-464, June 2009. This paper proposes a Proportional Fair Scheduling (PFS) scheme, which is a typical scheduler scheme that guarantees the fairness of a wireless network. In the LTE downlink, throughput performance in a multiuser environment (Objective optimization problem) that maximizes the performance of the PF approach. However, when formulating the optimization problem, various variables and constraints can be considered together to improve the performance, but at the same time, there is a difficulty in actual implementation due to an increase in computational complexity.

Korean Patent Laid-Open No. 10-2012-0081204 relates to a method and apparatus for scheduling quality of service (QOS) transmissions in a wireless communication system, which allocates UE-specific credits for providing quality of service in a wireless communication system, Decreasing the credit of the corresponding UE every time it is transmitted and increasing the credit for each unscheduled UE having each data flow with no data to be transmitted. However, according to the weight of the set user, As the dominant rule, the emphasis is on the provision of the user's service quality and the consideration of the fairness among the users is insufficient.

[1] R. Kwan, C. Leung, and J. Zhang, Proportional Fair Multiuser Scheduling in LTE, IEEE Signal Processing Letters, Vol. 16, 461-464, June 2009. [2] Shreedhar M .; Varghese, G. Efficient fair queuing using deficit round robin. Proc. ACM SIGCOMM Commun. Rev. 1995, 25, 231-242. [3] MH. Kim, and HS. Park, On Achieving short-term QoS and long-term fairness in high speed networks, Journal of High Speed Networks 13, 2004, 233-248.

A packet scheduling method and system for guaranteeing short-term delay and long-term fairness in an LTE environment according to an exemplary embodiment monitors radio channel state information and data transmission state information of a user terminal in an LTE environment, The present invention is intended to guarantee a short-term delay of data transmission of a user terminal and guarantee long-term fairness between user terminals through scheduling which appropriately adjusts a quantum value of the Deficit Round Robin scheduling.

In addition, focusing on the delay performance (i.e., delay performance), among the QoS parameters proposed in the LTE standardization document, a delay performance of a specific flow according to a QoS class identifier (QCI) .

In addition, mapping the RB (Resource Block), which is a basic unit of resource allocation of LTE, and the Quantum value of DPR (Deficit Surplus Estimator) .

A packet scheduling method in a wireless communication network, the method comprising: monitoring a data flow of a user terminal using a DSE (Deficit Surplus Estimator); and determining a quantum value of a DRR (Deficit Round Robin) And a step of adjusting.

According to an aspect, monitoring the data flow comprises: checking the expected delay performance of the user terminal at a predetermined period of time; and determining a new delay based on the determined expected delay performance and delay constraints. And determining whether to request a quantum value.

According to another aspect, determining whether to request the new quantum value comprises: determining whether the delay performance is in violation based on the expected delay performance and a delay constraint; Determining to request the new quantum value, and if it is determined that the delay capability is not violated, determining to retain the existing quantum value without requesting the new quantum value .

According to another aspect, adjusting the quantum value of the scheduling comprises calculating an average arrival traffic load for each of a predefined sampling period τ, And calculating a deficit and surplus state of the bandwidth corresponding to the user terminal at every computation period T- [tau].

According to another aspect, adjusting the quantum value of the scheduling comprises: comparing the existing quantum value with an existing quantum value and / or a new quantum value based on a lack of bandwidth and an excess state value corresponding to the user terminal, And updating the new quantum value with the new quantum value.

According to another aspect of the present invention, the step of updating with the new quantum value may include updating the existing quantum value to the new quantum value if the shortage and excess state value is equal to or greater than a value calculated based on the existing quantum value and the new quantum value. You can update it.

According to another aspect, the step of updating with the new quantum value comprises: if the shortage and excess state values are between a predetermined reference value and a value calculated based on the existing quantum value and the new quantum value, The value can be updated in part according to a predefined percentage.

According to another aspect, updating with the new quantum value comprises: rejecting the update request to the new quantum value if the shortage and excess state value are below a predetermined reference value, and maintaining the existing quantum value . ≪ / RTI >

A packet scheduling system in a wireless communication network, the system comprising: a monitoring unit monitoring a data flow of a user terminal using a DSE (Deficit Surplus Estimator); and a quantum value And a quantum value adjusting unit for adjusting the quantum value.

According to an aspect of the present invention, the monitoring unit includes a delay performance verifying unit for confirming an expected delay performance of the user terminal at predetermined regular time intervals, and a new quantum (delay constraint) Quantum) value of the input signal.

According to another aspect, the determination unit determines whether the delay performance is in violation based on the expected delay performance and a delay constraint, and when it is determined that the delay performance is violated, it is determined to request the new quantum value And if it is determined that the delay performance is not violated, it may be determined that the existing quantum value is maintained without requesting the new quantum value.

According to another aspect of the present invention, the quantum value adjusting unit calculates an average arrival traffic load for each predetermined sampling period τ, And a calculation unit for calculating deficit and surplus state values of the bandwidth corresponding to the terminal.

According to another aspect of the present invention, the quantum value adjustment unit may update the existing quantum value to the new quantum value based on a shortage and an excess state value, an existing quantum value, or a new quantum value corresponding to the user terminal Section.

According to another aspect, the update unit may update the existing quantum value with the new quantum value if the under-value and the excess value are equal to or greater than the value calculated based on the existing quantum value and the new quantum value.

According to another aspect, the update unit updates the existing quantum value to a predetermined schedule value if the shortage and excess state value exist between a predetermined reference value and a value calculated based on the existing quantum value and the new quantum value, It can be partially updated according to the ratio.

According to another aspect, the update unit may reject the update request to the new quantum value and maintain the existing quantum value if the shortage and excess state value are less than the predetermined reference value.

A packet scheduling method and system for guaranteeing short-term delay and long-term fairness in an LTE environment according to an exemplary embodiment monitors radio channel state information and data transmission state information of a user terminal in an LTE environment, It is possible to guarantee a short-term delay of data transmission of a user terminal and guarantee a long-term fairness between user terminals through scheduling which appropriately adjusts a Quantum value of the Deficit Round Robin scheduling.

In addition, by guaranteeing a short-term delay of data transmission of a user terminal, it is possible to effectively support a typical LTE QoS guarantee service such as VoIP and video streaming, and in the long term, Can also be guaranteed.

In addition, it is possible to support both Guaranteed Bit Rate (GBR) traffic and Non-Guaranteed Bit Rate (GBR) traffic in one unified system.

In addition, low complexity is very important in an LTE system where scheduling should be performed every 1 ms (TTI). By adjusting the quantum value through monitoring, it guarantees short-term delay and long-term fairness, So real system implementation can be easy.

1 is a block diagram illustrating an internal configuration of a packet scheduling system according to an embodiment of the present invention.
2 is a flowchart illustrating a packet scheduling method performed in a packet scheduling system according to an embodiment of the present invention.
Figure 3 is a flow diagram illustrating an operation for adjusting a quantum value in one embodiment of the present invention.
Figure 4 is a diagram provided to illustrate the operation of calculating under and over state values using DSE in one embodiment of the present invention.

Hereinafter, embodiments will be described in detail with reference to the accompanying drawings.

The embodiments of the present invention monitor radio channel state information and data transmission state information of a user terminal in a wireless communication network, i.e., an LTE (Long Term Evolution) environment, and adjust quantum values of DRR (Deficit Round Robin) And more particularly to a packet scheduling technique for guaranteeing short-term delay and long-term fairness. In particular, a data flow of a user terminal is monitored through a DSE (Deficit Surplus Estimator) Lt; / RTI > The DRR scheduling and quantum values are shown in the above non-patent document [2] Shreedhar M .; Varghese, G. Efficient fair queuing using deficit round robin. Proc. ACM SIGCOMM Commun. Rev. 1995, 25, 231-242.

DRR (Deficit Round Robin) scheduling is a scheduling technique that can be used in a situation where packet lengths are unknown. It is a scheduling technique that selects only flows satisfying specific conditions, rather than servicing all flows.

In the present embodiments, packet scheduling is performed in the above non-patent document [3] MH . Kim, and HS. Park, On Achieving short-term QoS and long-term fairness in high speed networks, Journal of High Speed Networks 13, 2004, 233-248. The wireless channel status information and the data transmission status information of the user terminal are monitored in the wireless network changing every moment, instead of correcting the short-term delay and the long-term fairness by adjusting the quantum value per class only for the wired network in which the service bandwidth shown in FIG. And adjusting the quantum value.

The terms used to monitor the data flow of the user terminal and adjust the quantum value of the DPR using the DSE (Deficit Surplus Estimator) in the present embodiments can be defined as shown in Table 1 below. In the following Table 1, t can represent the t-th computation period.

FIG. 1 is a block diagram illustrating an internal configuration of a packet scheduling system according to an exemplary embodiment of the present invention. FIG. 2 is a flowchart illustrating a packet scheduling method performed by a packet scheduling system, according to an embodiment of the present invention. to be.

Referring to FIG. 1, the packet scheduling system 100 may include a monitoring unit 110 and a quantum value adjuster 120. The monitoring unit 110 includes a delay performance verification unit 111 and a determination unit 112. The quantum value adjustment unit 120 may include a calculation unit 121 and an update unit 122. [ The packet scheduling system 100 monitors a user data flow to at least one user terminals (e.g., user terminal 1 to user terminal k) belonging to its LTE cell in an LTE environment Scheduling can be performed.

2, each of the steps 210 and 220 may be performed by the monitoring unit 110 and the quantum value adjuster 120, which are components of the packet scheduling system 100 of FIG.

In step 210, the monitoring unit 110 may monitor the data flow of at least one user terminal using a DSE (Deficit Surplus Estimator). Hereinafter, a case of monitoring a data flow with respect to one specific user terminal will be described as an example, but this embodiment corresponds to the embodiment, and data flows of each of a plurality of user terminals can be monitored.

) 및 달성 가능 레이트(achievable rates)인

에 기초하여 확인될 수 있다. In step 211, the delay performance verifying unit 111 can confirm the expected delay performance of the user terminal at predetermined time intervals. Here, the expected delay performance is determined by a backlog (i.e.,

) And achievable rates

As shown in FIG.

를 달성 가능 레이트

로 나눔으로써, 해당 주기에서의 상기 기대 지연 성능(

/

)을 확인할 수 있다. 여기서, s는 시간을 나타내는 인덱스, 즉, time s를 의미할 수 있다. 지연 성능 확인부(111)는 기정의된 일정시간마다 주기적으로 상기 기대 지연 성능을 확인할 수 있다.For example, the delay performance verifying unit 111 may determine that the backlog

Achievable rate

, The expected delay performance (< RTI ID = 0.0 >

/

)can confirm. Here, s may mean an index indicating time, i.e., time s. The delay performance verification unit 111 can periodically check the expected delay performance at predetermined time intervals.

)에 기초하여 새로운 퀀텀(Quantum)값을 요청할지 여부를 결정할 수 있다.In step 212, the determination unit 112 determines the expected delay performance periodically checked at predetermined time intervals and the delay constraint in the corresponding period,

) To determine whether to request a new Quantum value.

In step 220, the quantum value adjuster 120 may adjust the quantization value of the DRR (Deficit Round Robin) scheduling based on the monitoring result.

In step 221, the calculation unit 121 may calculate an average arrival traffic load at a predefined sampling period?.

을 계산할 수 있다.In step 222, the calculation unit 121 calculates a shortage and an excess state value for each of the predefined measurement periods T- < RTI ID = 0.0 >

Can be calculated.

과 기존의 퀀텀값(

) 및 새로운 퀀텀값(

)에 기초하여 기존 퀀텀값을 새로운 퀀텀값으로 업데이트하거나 또는 기정의된 일정 비율에 해당하는 일부만 업데이트하거나 또는 기존 퀀텀값을 그대로 유지할 수 있다. 즉, 212 단계에서 새로운 퀀텀값을 요청한 경우, 요청한 새로운 퀀텀값으로 기존의 퀀텀값을 변경할지 말지, 아니면 일부만 업데이트할지 여부를 결정할 수 있다.In step 223, the update unit 122 updates the calculated shortage and excess state values, that is,

And existing quantum values (

) And the new quantum value (

) To update the existing quantum value to a new quantum value, or to update only a portion corresponding to a predetermined percentage, or to retain the existing quantum value. That is, when a new quantum value is requested in step 212, it may be determined whether to change the existing quantum value to the requested new quantum value or to update only a part of the quantum value.

Figure 3 is a flow diagram illustrating an operation for adjusting a quantum value in one embodiment of the present invention.

3 illustrates the operation of adjusting the quantum values based on parameters indicating an existing quantum value, a new quantum value, a delay constraint, etc., in the operation of FIG. 2, And how it is adjusted and updated.

Each of the steps 310 to 395 of FIG. 3 may be performed by the monitoring unit 110 and the quantum value adjusting unit 120, which are components of the packet scheduling system 100 of FIG.

에 기초하여 업데이트 퀀텀값을 새로운 퀀텀값으로 업데이트할지, 아니면 기존 퀀텀값을 그대로 유지할지 여부를 결정하는 구간에 해당할 수 있다.Referring to FIG. 3, DRR-based packet scheduling according to the present invention can be roughly divided into two periods (Examination Phase and Quantum Adjustment Phase). The first phase corresponds to a period for determining whether to request a new quantum value based on the expected delay performance and the delay constraint. The second phase corresponds to a new quantum value, Status value

The update quantum value may be updated to a new quantum value or the existing quantum value may be maintained as it is.

)를 달성 가능 레이트(achievable rates)인

로 나눔으로써, 기대 지연 성능을 확인할 수 있다. First, in step 310, the delay performance verifying unit 111 determines the delay log of the user terminal's baglog (i.e.,

) To the achievable rates

, The expected delay performance can be confirmed.

는, k번째 사용자 단말의 클래스 i의 백로그(baglog)를 나타내고, 달성 가능 레이트(achievable rates)

는 t번째 샘플(sample, 즉, t번째 측정 주기에 해당하는 샘플)의 사용자 단말 k의 클래스(class) i에 해당하는 달성 가능 레이트를 나타낼 수 있다.Here,

Denotes the baglog of class i of the kth user terminal, and denotes the achievable rate,

May represent the achievable rate corresponding to class i of the user terminal k of the t-th sample (sample, i.e., the sample corresponding to the t-th measurement period).

를 달성 가능 레이트

로 나눈 기대 지연 성능과 상기 지연 제약(delay constraint) d_i의 크기를 비교하여 새로운 퀀텀값을 요청할지 여부를 결정할 수 있다.The determination unit 112 determines whether or not the backlog

Achievable rate

Compared to the amount of delay divided by the expected performance and the delay constraints (delay constraint) to d _i may determine whether or not to request a new quantum value.

을 요청할 수 있다. 이때, 상기 기대 지연 성능이 상기 지연 제약 d_i이하이면, 결정부(112)는 상기 새로운 퀀텀값을 요청하지 않고 기존 퀀텀값

을 그대로 유지하는 것으로 결정할 수 있다. For example, if the expected delay performance is larger than the delay constraint d _i , the determination unit 112 determines that the delay performance is in violation, and the new quantum value

. At this time, if the expected delay performance is less than the delay constraint d _i , the determination unit 112 does not request the new quantum value,

As shown in FIG.

을 요청하는 것으로 결정되면, 퀀텀값 조정부(120)는 새로운 퀀텀값을 요청할 수 있다. 즉, 퀀텀값 조정부(120)는 새로운 퀀텀값

을 계산할 수 있다.In step 320, a new quantum value

The quantum value adjuster 120 may request a new quantum value. That is, the quantum value adjusting unit 120 adjusts the new quantum value

Can be calculated.

을 계산할 수 있다.For example, the quantum value adjustment unit 120 may calculate a new quantum value

Can be calculated.

[Equation 1]

)을 사용자 단말 k의 클래스 i의 MCS(Modulation Coding Scheme) 레벨

과 지연 제약 d_i 간의 곱으로 나눔으로써, 새로운 퀀텀값

을 계산할 수 있다.According to Equation (1), the quantum value adjuster 120 can calculate the product of the backlog B _{i, k} (t) of the class i of the user terminal k, the sampling period τ, and the number of samples T. Then, the quantum value adjusting unit 120 adjusts the product (

) To the MCS (Modulation Coding Scheme) level of the class i of the user terminal k

And the delay constraint d _i By dividing by the product of squares, a new quantum value

Can be calculated.

과 부족 및 과잉 상태값

에 기초하여 기존 퀀텀값을 새로운 퀀텀값으로 업데이트할 수 있다. Then, the quantum value adjusting unit 120 calculates a new quantum value

And under and over state values

To update the existing quantum value to the new quantum value.

과 서비스값 및 미리 정의된 기준값을 비교하여 상기 새로운 퀀텀값으로 업데이트를 수행할 수 있다. 예를 들어, 퀀텀값 조정부(120)는 상기 새로운 퀀텀값

과 기존의 퀀텀값

간의 차이값을 계산할 수 있다. 그리고, 계산된 차이값과 미리 정의된 측정 주기(computation period) Δ, 및 MCS(Modulation Coding Scheme) 레벨

을 곱함으로써, 해당 주기에 사용자 단말에 할당된 대역폭에 해당하는 서비스값을 계산할 수 있다.At this time, the quantum value adjuster 120 adjusts the values of the under and over state values

The service value and the predefined reference value to perform update with the new quantum value. For example, the quantum value adjustment unit 120 may calculate the new quantum value

And existing quantum values

Can be calculated. Then, the computed difference value, a predefined computation period DELTA, and an MCS (Modulation Coding Scheme) level

The service value corresponding to the bandwidth allocated to the user terminal can be calculated in the corresponding period.

이 상기 계산된 서비스값 이상이면, 340 단계에서, 퀀텀값 조정부(120)는 기존 퀀텀값을 새로운 퀀텀값으로 업데이트할 수 있다. 즉, 퀀텀값 조정부(120)는 업데이트 퀀텀값

을 기존 퀀텀값

에서 새로운 퀀텀값

으로 설정함으로써, 퀀텀값을 업데이트할 수 있다. 이처럼, 요청된 새로운 퀀텀값

에 기초하여 계산된 서비스 값이 측정 주기 Δ동안에 측정된 상기 부족 및 과잉 상태값

보다 작으면, 퀀텀값의 업데이트 요청을 수락하여 업데이트 퀀텀값

을 기존 퀀텀값

에서 새로운 퀀텀값

으로 업데이트할 수 있다.At step 330, the under and over state values

The quantum value adjustment unit 120 may update the existing quantum value to a new quantum value. That is, the quantum value adjusting unit 120 may calculate the update quantum value

To an existing quantum value

The new quantum value

, The quantum value can be updated. Thus, the requested new quantum value

Lt; RTI ID = 0.0 > A < / RTI > measured during the measurement period <

, The update request of the quantum value is accepted and the update quantum value

To an existing quantum value

The new quantum value

.

이 상기 계산된 서비스값보다 작고, 미리 정의된 기준값(예컨대, 0)보다 크면, 즉,

이 0과 상기 서비스값 사이에 존재하면, 360 단계에서, 퀀텀값 조정부(120)는 측정 주기 Δ동안에 측정된 과잉(surplus) 비율만큼 업데이트 퀀텀값

을 일정 부분만 업데이트할 수 있다.In step 350, the measured under and over state values < RTI ID = 0.0 >

Is smaller than the calculated service value and greater than a predefined reference value (e.g., 0), that is,

Is between the zero and the service value, in step 360, the quantum value adjuster 120 adjusts the update quantum value < RTI ID = 0.0 >

Can only update a certain portion.

을 일정 부분만 업데이트할 수 있다.For example, the quantum value adjustment unit 120 may calculate an update quantum value (eigenvalue) by a surplus ratio measured during the measurement period [Delta]

Can only update a certain portion.

&Quot; (2) "

을 측정 주기 Δ동안에 해당하는 MCS 레벨로 나눈값에 해당하는 과잉 비율만큼 상기 업데이트 퀀텀값

을 전체가 아닌 일부만 업데이트할 수 있다.According to Equation (2), the quantum value adjuster 120 adjusts the values of the shortage and excess state values

Is divided by the corresponding MCS level during the measurement period < RTI ID = 0.0 > A < / RTI &

Can be updated only partially.

이 미리 정의된 기준값(예컨대, 0)보다 작으면, 380 단계에서, 퀀텀값 조정부(120)는 새로운 퀀텀값

으로의 업데이트 요청을 거절할 수 있다. 즉, 업데이트 퀀텀값

을 기존 퀀텀값

으로 그대로 설정을 유지할 수 있다.In step 370, the shortage and excess state values measured during the measurement period [Delta]

Is smaller than a predefined reference value (e.g., 0), in step 380, the quantum value adjusting unit 120 sets a new quantum value

Lt; / RTI > That is, the update quantum value

To an existing quantum value

The setting can be maintained as it is.

에 기초하여 GBR(Guaranteed Bit Rate)관련 퀀텀 풀(Quantum pool)을 업데이트할 수 있다. In step 390, the quantum value adjuster 120 adjusts the update quantum value

A Quantum pool related to a guaranteed bit rate (GBR) can be updated.

For example, the quantum value adjuster 120 may update the GBR-related quantum pool based on Equation (3) below.

&Quot; (3) "

는 사용자 단말 k의 클래스 i에 해당하는 퀀텀값을 나타내고,

는 사용자 단말 k의 클래스 i에 대해 업데이트된 퀀텀값을 나타낼 수 있다.In Equation (3), Q _p denotes an existing quantum pool,

Represents the quantum value corresponding to the class i of the user terminal k,

May represent an updated quantum value for class i of user terminal k.

In step 395, the quantum value adjuster 120 may update the quantum value of the Non-Guaranteed Bit Rate (GBR) class based on the updated quantum pool.

For example, the quantum value adjuster 120 may redistribute the updated quantum pool to Non-GBR (Guaranteed Bit Rate) classes based on Equation (4) below.

&Quot; (4) "

는 업데이트된 GBR관련 퀀텀 풀을 나타내고, Q'_j는 기존의 Non-GBR클래스 j가 갖는 퀀텀값 Q_j에 비례하여 재분배된 퀀텀값을 나타낼 수 있다.In Equation (4)

Denotes an updated GBR-related quantum pool, and Q ' _j may represent a redistributed quantum value proportional to a quantum value Q _j of an existing non-GBR class j.

 As described above, the packet scheduling system 100 of the present invention can reduce the computational complexity by not only updating the quantum value every period but also by determining whether the delay performance is in violation and updating the quantum value only when the delay performance is violated. Then, after updating the quantum value of the QoS guaranteed class (that is, the GBR-related quantum value), the corresponding quantum pool (that is, the GBR-related quantum pool) is updated and used in the QoS guaranteed class And GBR-related classes to the non-GBR-related classes, thereby ensuring a short-term delay of data transmission of the user terminal, while maintaining long-term fairness among the user terminals May be performed.

Figure 4 is a diagram provided to illustrate the operation of calculating under and over state values using DSE in one embodiment of the present invention.

FIG. 4 shows the relationship between the average arrival traffic load a _{i, k} (t) and the achievable rate R _{i, k} (t) measured for each sampling period τ.

을 계산할 수 있다. 예컨대, 도 4의 윈도우(measurement window)를 이용하여 측정 주기 T-τ마다 부족 및 과잉 상태(Deficit and Surplus State)값

을 계산할 수 있다(즉, 도 4의 + 또는 -에 해당하는 값을 계산할 수 있다).Referring to FIG. 4, the quantum value adjuster 120 may calculate an average arrival traffic load at every predefined sampling period?. Then, a deficit and a surplus state value (a deficit and a surplus state) are calculated in a sliding window manner at every predefined computation period T-

Can be calculated. For example, by using the measurement window of FIG. 4, a deficit and surplus state value

(I.e., a value corresponding to + or - in FIG. 4 can be calculated).

을 계산할 수 있다.For example, the quantum value adjusting unit 120 may calculate a deficit and surplus state value

Can be calculated.

&Quot; (5) "

는 t번째 샘플(즉, t번째 측정 주기에 해당하는 샘플)에서 사용자 단말 k의 클래스(class) i에 해당하는 달성가능 레이트(achievable rate) R_i,k(t)와 t번째 샘플에서 사용자 단말 k의 클래스(class) i의 도착 트래픽(arrival traffic)에 대해 측정된 로드값(load) a_i,k(t) 간의 차이값에 해당할 수 있다. 즉,

는 도 4에서, 매 샘플링 주기 τ마다 + 또는 -로 표시된 구간(또는 영역) 범위에 해당하는 값을 나타낼 수 있다. 그리고, T는 샘플링 주기 τ에 해당하는 샘플들의 수를 나타낼 수 있다.In Equation (5), D _{i, k} (t-1) is a tributary corresponding to class i of the user terminal k in the t-1 th sample (sample, i.e., And a deficit and surplus state value. And,

(T) corresponding to the class i of the user terminal k in the t-th sample (i.e., the sample corresponding to the t-th measurement period) and the achievable rate R _{i, k} may correspond to a difference value between a load value a _{i, k} (t) measured for arrival traffic of a class i of _k . In other words,

In FIG. 4, a value corresponding to a range (or region) indicated by + or - for every sampling period? Can be represented. And T can represent the number of samples corresponding to the sampling period?.

As described above, the quantum value adjuster 120 adjusts the quantum value based on the value calculated using the DSE (Deficit Surplus Estimator) to update the long term unfairness due to the traffic of the ill-behaving user terminal. Can be prevented.

The method according to an embodiment may be implemented in the form of a program command that can be executed through various computer means and recorded in a computer-readable medium. The computer-readable medium may include program instructions, data files, data structures, and the like, alone or in combination. The program instructions to be recorded on the medium may be those specially designed and configured for the embodiments or may be available to those skilled in the art of computer software. Examples of computer-readable media include magnetic media such as hard disks, floppy disks and magnetic tape; optical media such as CD-ROMs and DVDs; magnetic media such as floppy disks; Magneto-optical media, and hardware devices specifically configured to store and execute program instructions such as ROM, RAM, flash memory, and the like. Examples of program instructions include machine language code such as those produced by a compiler, as well as high-level language code that can be executed by a computer using an interpreter or the like.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. For example, it is to be understood that the techniques described may be performed in a different order than the described methods, and / or that components of the described systems, structures, devices, circuits, Lt; / RTI > or equivalents, even if it is replaced or replaced.

Therefore, other implementations, other embodiments, and equivalents to the claims are also within the scope of the following claims.

Claims (16)

A packet scheduling method in a wireless communication network,
Monitoring a data flow of a user terminal using a DSE (Deficit Surplus Estimator); And
Adjusting the quantum value of the DRR (Deficit Round Robin) scheduling based on the monitoring result
Lt; / RTI >
Wherein monitoring the data flow comprises:
Confirming an expected delay performance of the user terminal at predetermined time intervals;
Determining whether the delay performance is in violation by comparing the expected delay performance and the size of the delay constraint;
Determining that the delay capability is in violation and requesting a new quantum value if the expected delay performance is greater than the delay constraint; And
Determining that the delay capability is not in violation if the expected delay performance is below the delay constraint and determining to retain the existing quantum value without requesting a new quantum value
Lt; / RTI >
Wherein adjusting the quantum value of the scheduling comprises:
If it is determined to request a new quantum value, calculating a new quantum value;
Calculating an average arrival traffic load at every predefined sampling period τ;
Calculating deficit and surplus states of a bandwidth corresponding to a user terminal every predetermined computation period T-T;
Calculating a difference value between the new quantum value and the existing quantum value, and calculating a service value corresponding to the bandwidth allocated to the user terminal based on the difference value;
Updating the existing quantum value with the new quantum value if the shortage and excess state value is greater than or equal to the service value;
Updating the existing quantum value according to a predetermined percentage if the shortage and excess state value is smaller than the service value and greater than a predetermined reference value;
Rejecting an update request to a new quantum value and maintaining an existing quantum value if the shortage and excess state values are less than the reference value;
Updating a Guaranteed Bit Rate (GBR) related quantum pool based on the updated quantum value; And
Updating the quantum value of the Non-Guaranteed Bit Rate (GBR) class based on the updated quantum pool
Lt; / RTI > delete delete delete delete delete delete delete A packet scheduling system in a wireless communication network,
A monitoring unit monitoring a data flow of a user terminal using a DSE (Deficit Surplus Estimator); And
And a quantum value adjuster for adjusting a quantum value of the DRR (Deficit Round Robin) scheduling based on the monitoring result
Lt; / RTI >
The monitoring unit,
The expected delay performance of the user terminal is checked at predetermined time intervals,
Determines whether the delay performance is in violation by comparing the expected delay performance and the size of the delay constraint,
If the expected delay performance is greater than the delay constraint, determining that the delay performance is in violation and deciding to request a new quantum value,
Determining that the delay performance is not violated and retaining the existing quantum value without requesting a new quantum value if the expected delay performance is below the delay constraint,
Wherein the quantum value adjusting unit comprises:
If it is determined to request a new quantum value, a new quantum value is calculated,
Calculating an average arrival traffic load for each of a predetermined sampling period τ and determining a lack of bandwidth and an excess state value corresponding to the user terminal at every predetermined computation period T- Deficit and Surplus State)
Calculating a difference value between the new quantum value and the existing quantum value, calculating a service value corresponding to the bandwidth allocated to the user terminal based on the difference value,
Updating the existing quantum value to the new quantum value if the shortage and excess state value is equal to or greater than the service value,
If the shortage and excess state value are smaller than the service value and larger than the predetermined reference value, the existing quantum value is partially updated according to the predetermined percentage,
If the shortage and excess state value are less than the reference value, reject the update request to the new quantum value and maintain the existing quantum value,
Updating a Quantum pool related to a Guaranteed Bit Rate (GBR) based on the updated quantum value,
Updating quantum values of Non-Guaranteed Bit Rate (GBR) classes based on an updated quantum pool
The packet scheduling system comprising: delete delete delete delete delete delete delete

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