KR20120090639A - Method and system for wire and wireless network connection, recording medium for the same - Google Patents

Abstract

PURPOSE: A wire/wireless network integration system, a method thereof, and recording medium for the same are provided to efficiently combine EPON and WiMAX with the application of a centralized scheduling method. CONSTITUTION: A bandwidth request message is transmitted from one or more subscriber terminals to a JC(Joint Controller)(300) through a base station(200). The bandwidth request message is transmitted as a REPORT message when data is transmitted from an ONU(Optical Network Unit)(100) to an OLT(Optical Line Terminal) of an EPON(Ethernet Passive Optical Network). A GATE message is transmitted to the base station and the JC through the ONU. The data is transmitted from the subscriber terminal to the OLT.

Description

METHOD AND SYSTEM FOR WIRE AND WIRELESS NETWORK CONNECTION, RECORDING MEDIUM FOR THE SAME

The present invention relates to a wired / wireless network integration method, a system and a recording medium therefor, and more particularly, to a wired / wireless network integration method, a system and a recording medium for the broadband wireless access service.

Unlike in the past, when voice services were the main traffic of wireless networks, the traffic demands of wireless subscribers for high-speed data services such as wireless internet, mobile IPTV, video telephony, and point-to-point services are increasing rapidly. . These changes are placing additional bandwidth increases on the cell site. Service providers and equipment operators are looking for solutions to overcome the capacity limitations of existing technologies and build a wireless backhaul while minimizing cost bleeding. Existing copper line-based access solutions are not able to accommodate all of the rapidly increasing subscriber traffic and are expected to saturate sooner or later. The solution to breakthrough in this situation is Passive Optical Network (PON) technology. PON is attracting attention as a technology to replace the existing wireless backhaul because it provides breakthrough network capacity with the optical gain of optical fiber and low maintenance and repair cost. Among them, Ethernet PON (EPON) has a large capacity and uses Time-Division Multiple Access (TDMA) (or Time-Division Multiple (TDM)) technology. It provides an economical channel, making it one of the carrier's favorite PON technologies.

Meanwhile, WiMAX (Worldwide Interoperability for Microwave Access) technology has emerged in response to the rapid growth of broadband Internet and multimedia services. WiMAX has become an attractive technology that delivers high-speed wireless access wherever it is, while delivering high data rates, low cost of equipment, and reliable quality of service.

Therefore, in order to provide users with economical efficiency and wide bandwidth and mobility, many studies have been conducted in terms of optical and wireless coupling, and the optical and wireless network coupling is an architecture and a physical layer. And in terms of MAC layer. As part of this research, the combination of EPON and WiMAX is being studied.

An object of the present invention is to provide a wired-wireless network integration method that can efficiently combine EPON and WiMAX by applying a centralized scheduling scheme.

Another object of the present invention is to provide a wired-wireless network integration system for achieving the above object.

In order to achieve the above object, there is provided a method for integrating a wired / wireless network into an EPON having one or more optical termination units (hereinafter referred to as ONUs), a WiMAX having one or more base stations and a plurality of subscriber stations, and an ONU and the ONU. In the wire-wireless network integration method having a joint controller (hereinafter referred to as JC) for connecting the corresponding base station, a bandwidth request message for requesting bandwidth for data transmission from one or more subscriber stations of the plurality of subscriber stations Transmitting to the JC via the corresponding base station of the one or more base stations, when the previously approved data is transmitted from the ONU to the circuit terminal of the EPON (hereinafter OLT), the bandwidth request message is sent to the previously approved data. Sent as a REPORT message with, responding to the REPORT message. In response to the transmission of the GATE message including the bandwidth information approved by the OLT to the JC and the base station through the ONU, the bandwidth approved in response to the GATE message transmitted to the JC and the base station and the transmission time. And transmitting together to the subscriber station, and transmitting data from the subscriber station to the OLT through the base station and the ONU at the transmission time.

In order to achieve the above object, there is provided a method for integrating a wired / wireless network into an EPON having one or more optical termination units (hereinafter referred to as ONUs), a WiMAX having one or more base stations and a plurality of subscriber stations, and an ONU and the ONU. In the wire-wireless network integration method having a joint controller (hereinafter referred to as JC) for connecting the corresponding base station, a bandwidth request message for requesting bandwidth for data transmission from one or more subscriber stations of the plurality of subscriber stations Transmitting to the JC via the corresponding base station of the one or more base stations, the bandwidth request message is classified and stored according to the service class, and previously approved data is transferred from the ONU to the EPON line terminal (hereinafter referred to as OLT). When transmitted, the classified and stored bandwidth request message is Transmitting as a REPORT message together with previously approved data, a GATE message including bandwidth information approved by the OLT in response to the REPORT message being sent to the JC and the base station via the ONU, the JC and In response to the GATE message transmitted to the base station, an approved bandwidth is transmitted to the subscriber station with a transmission time, and data is transmitted from the subscriber station to the OLT through the base station and the ONU at the transmission time. With steps.

Previously approved in a WiMAX, line terminal (OLT) having one or more base stations receiving bandwidth requests and data for data transmission from one or more of the plurality of subscriber stations to achieve the other object An EPON having one or more optical termination devices (hereinafter ONUs) for transmitting a bandwidth request message to the OLT as a REPORT message together with the data, and collecting the bandwidth request applied to the base station to generate the bandwidth request message; A joint controller (hereinafter referred to as JC) for storing bandwidth information included in the GATE message stored in the ONU and transmitted in response to the bandwidth request message from the OLT to the one or more subscriber stations through the one or more base stations. It is provided.

Accordingly, the method, system, and recording medium for the wire-wireless network integration method for the broadband wireless access service of the present invention can reduce the bandwidth request and data request time by using the centralized scheduling scheme between the wired network EPON and the wireless network WiMAX. It is possible to provide an efficient method for integrating wired and wireless networks and systems.

1 illustrates an EPON-WiMAX integrated system as an example of a wired-wireless integrated system according to the present invention.
2 and 3 show the functional module of the cooperative optical terminator-base station structure (COB) and the hybrid optical terminator-base station structure (HOB) of FIG. 1, respectively.
4 illustrates an example of the operation of functional modules for the centralized scheduling scheme using the COB of FIG. 2 in accordance with the present invention.
FIG. 5 is a timing diagram for describing an operation of the centralized scheduling scheme of FIG. 4.
6 shows the delay time gain of the central scheduling scheme of the present invention compared to the existing independent scheduling scheme.
7 illustrates an element in which a packet delay occurs in an optical termination unit (ONU).
8 and 9 illustrate average queuing delays of a central scheduling scheme and an independent scheduling scheme.
10 and 11 illustrate average ETE delays of the centralized scheduling scheme and the independent scheduling scheme.
12 and 13 illustrate average throughputs of the centralized scheduling scheme and the independent scheduling scheme.
14 and 15 show an average end-to-end delay and a maximum ETE delay.
16 shows the average throughput from the distributor to the line terminal OLT.

In order to fully understand the present invention, the operational advantages of the present invention, and the objects achieved by the practice of the present invention, reference should be made to the accompanying drawings which illustrate preferred embodiments of the present invention and the contents described in the accompanying drawings.

Hereinafter, the present invention will be described in detail with reference to the preferred embodiments of the present invention with reference to the accompanying drawings. However, the present invention can be implemented in various different forms, and is not limited to the embodiments described. In addition, in order to clearly describe the present invention, parts irrelevant to the description are omitted, and the same reference numerals in the drawings indicate the same members.

Throughout the specification, when an element is referred to as " including " an element, it does not exclude other elements unless specifically stated to the contrary. The terms "part", "unit", "module", "block", and the like described in the specification mean units for processing at least one function or operation, And a combination of software.

1 illustrates an EPON-WiMAX integrated system as an example of a wired-wireless integrated system according to the present invention.

In the present invention, EPON is used as the wired network, and WiMAX is used as the wireless network. The combination of EPON and WiMAX creates a wired-wireless network integration system for broadband wireless access services.

The combination of EPON and WiMAX results in the following complementary synergy effects: The first is large capacity mobility. EPON is mobile and offers high capacity wired subscriber services due to the high bandwidth gain of fiber. In comparison, WiMAX provides mobility, although the base station capacity is limited because of the radio spectrum. Second is the provision of a wide range of services. The existing copper circuit-based networks, T-1 / E-1 and DSL, have a long transmission distance of less than 5 km, while EPON can service up to 20 km. This reduces the cost and time required to add repeaters to extend service coverage in existing networks. Finally, it is a balance of reasonable transmission capacity. Due to its good price performance, the 16 splitting ratio EPON, the most widely used commercially, has a downlink 65Mbps transmission capacity. This closely matches the current maximum transmission capacity of WiMAX base stations in service at 70Mbps, minimizing bottlenecks in capacity differences when combining the two technologies.

For the successful combination of EPON and WiMAX, technical issues such as transmission scheduling and QoS provisioning must be addressed at the Media Access Control (MAC) layer. In particular, the Independent Scheduling (IS) scheme, which was originally designed to combine PON and WiMAX, causes significant performance degradation of existing integrated systems because PON and WiMAX independently reserve and transmit bandwidth. In other words, the existing IS scheme does not share bandwidth reservation and QoS mapping information between EPON and WiMAX, resulting in packet delay in the integrated network. In addition, since EPON and WiMAX use different MAC protocols, QoS is disconnected due to heterogeneous MAC characteristics.

In the present invention, in order to solve this problem that occurs in the non-cooperative and inefficient coupling structure between the optical network unit (ONU) and the base station (BS), Centralized Scheduling (CS) Provide techniques. In order to solve the problem of QoS disconnection, the QoS transmission protocol is provided along with an integrated system structure to guarantee QoS between EPON and WiMAX.

As shown in FIG. 1, in the present invention, an independent ONU-BS (hereinafter referred to as IOB) (IOB), a cooperative optical termination-base station structure (Combined ONU-) is a combination structure of an EPON and WiMAX integrated system. Three structures are proposed: BS (COB) (COB) and Hybrid ONU-BS (HOB) (HOB).

First, the IOB is the simplest implementation that connects the ONU directly to the BS through a standard Ethernet interface. This architecture can leverage existing ONU and BS infrastructures, thus benefiting from no additional costs and requirements. However, since EPON and WiMAX operation are independent, the ONU does not have information on how much bandwidth of a given SS is from the BS, and the BS does not know the amount of bandwidth of the OLT allocated to the ONU. Therefore, the IOB is difficult to maximize use of both the bandwidth of the optical network and the bandwidth of the wireless network, thereby lowering the overall utilization of the combined system.

The COB may be considered as a form of arranging a joint controller (hereinafter referred to as JC) between the ONU and the BS as shown in FIG. 1. Intuitively, this architecture looks like a mix of ONU, BS, and JC, but works logically as a single system with combined EPON and WiMAX. JC is an additional device for sharing state information between EPON ONU and WiMAX BS for traffic management of the combined network. By JC, COB provides a sufficiently transparent coupling without interference between existing network facilities for EPON and WiMAX respectively. However, site rental and maintenance costs for JC can be high because JC is a physically separate facility.

HOB provides a tighter binding structure than COB. A distinctive feature of HOB is the ability to include all functional modules of ONU, BS and JC on a small printed circuit board (PCB) in a single space, reducing capital expenditures (CAPEX) and operating costs (OPEX). It can be reduced. The HOB is functionally identical to the COB except that the ONU, BS and JC are physically integrated into one device. Thus, like a COB, it manages traffic on a JC-coupled network.

The HOB and COB structures proposed in the present invention operate on specially designed functional modules included in the JC. HOB and COB architectures are designed to provide bandwidth allocation and QoS for combined networks based on functional modules for QoS mapping, WiMAX request aggregating, and EPON grant processing, respectively. do. In particular, this functional module immediately sends an ETE QoS (End-To-End) between the subscriber station (SS) and the optical line terminal (OLT) as soon as the connection request and authorization data from the subscriber station (SS) is transmitted. Information is shared and processed to provide QoS.

2 and 3 show the functional module of the COB and the HOB of FIG. 1, respectively.

The function module of the COB in FIG. 2 is the ONU 100 included in the EPON and the BS 120 included in the WiMAX, and the EPON ONU for traffic management of the combined network disposed between the ONU and the BS. A JC 300 sharing state information between the 100 and the WiMAX BS 200 is provided.

EPON ONU 100 includes an EPON ONU scheduler 110, an ONU queue 120, a packet classifier 130, and a REPORT generator 140. The EPON ONU scheduler 110 transmits a burst of data in the OLT at the scheduled time. The ONU queue 120 includes a plurality of queues to temporarily store data and deliver the data to the EPON ONU scheduler 110 at a timing specified by the EPON ONU scheduler 110. The ONU queue 120 may specify a priority for each of the plurality of queues. The packet classifier 130 may classify the applied data according to various applications corresponding to each data and store the data in a plurality of queues of the ONU queue 120. In particular, when a plurality of queues of the ONU queue 120 have different priorities, the corresponding data may be stored in the queue having the corresponding priority in consideration of the grade of the service corresponding to the authorized data. In this case, the priority of each data may be designated by the QoS mapper 310 of the JC 300. The REPORT generator 140 generates an 'EPON REPORT' message to be transmitted to the OLT and transmits the generated message to the ONU scheduler 110. The 'EPON REPORT' message will be described later.

WiMAX BS 200 includes a WiMAX Uplink scheduler 210, a grant generator 220, and a packet rebuilder 230. The WiMAX uplink scheduler 210 serves to redistribute the given bandwidth for the COB to the plurality of subscriber stations (SS), and the grant generator 220 is the actual amount of bandwidth granted to each of the plurality of subscriber stations (SS) Notifies each subscriber station (SS). In addition, the packet reconstructor 230 receives data generated by various applications used by the plurality of subscriber stations (SS) and reconstructs the data into an easy form for transmission.

The JC 300 includes a WiMAX Request Aggregator 310, an EPON Grant Processor 320, and a QoS Mapper 330. The WiMAX request concentrator 330 collects data transmission requests of various applications that are authorized from a plurality of subscriber stations (SS) from the WiMAX BS 200 and transmits the collected data to the REPORT generator 140 of the EPON ONU 100. Forward the request. The EPON approval processor 330 confirms the bandwidth approved from the OLT of the EPON through the EPON ONU 100 and notifies the WiMAX uplink scheduler 210 of the WiMAX BS 200. The QoS mapper 320 mediates the priority of the EPON and the service class of the WiMAX in order to prevent QoS degradation that may occur due to the difference between the number of priorities designated in the EPON and the number of service classes of the WiMAX. . That is, the QoS mapper 320 is classified according to the WiMAX service level of the application to map the data transmission requests collected by the WiMAX request concentrator 330 to the EPON ONU 100 by one-to-one mapping to the divided priorities of the EPONs. Notify me.

As a result, JC 300 may arbitrate bandwidth reservation and QoS between EPON and WiMAX using QoS mapper 310, EPON authorization processor 320, and WiMAX request concentrator 330.

In the functional module of the HOB of FIG. 3, the functional module of the COB illustrated in FIG. 2 is integrated into one device, and the configuration of the functional module and the operation of each functional module are the same as the functional module of the COB.

Table 1 shows the advantages and disadvantages of each of the three structures of IOB, COB and HOB shown in FIG. Table 1 analyzes the advantages and disadvantages of each of the three structures in terms of topology, cost, and network performance. Looking at the advantages and disadvantages of each structure with reference to Table 1, IOB can first reuse the existing ONU and BS infrastructure to achieve the lowest equipment cost. However, since bandwidth allocation and packet scheduling in the IOB are completely independent in OPEN and WiMAX, respectively, there is a limitation that the IOB must use an IS scheme for transmitting data from the SS to the OLT. In addition, when the user is a WiMAX subscriber, due to the mismatch between the priority of the EPON in the service level agreement (SLA) and the service class of the WiMAX, it is difficult to expect sufficient bandwidth usage and high quality QoS in the EPON. And since COBs must have ONU, BS and JC separately, they require the most expensive site rental costs. In addition, JC must be added, requiring intermediate equipment costs. However, by applying the CS scheme of the present invention, efficient bandwidth allocation and packet scheduling can be performed by the JC, thereby providing a high level of bandwidth usage and QoS. Finally, the HOB is functionally identical to the COB except that the ONU, BS and JC are provided in one physical device, so that the HOB can be constructed at a relatively low site rental cost compared to the COB. However, while COB adds JC to existing ONU and BS, HOB does not utilize existing ONU and BS, and therefore requires high installation costs due to the installation of new equipment. If the HOB is widely deployed in wired-wireless networks, the HOB can provide the highest cost efficiency. As described above, since the HOB is functionally the same as the COB, the CS technique can provide a high level of bandwidth usage and QoS.

FIG. 4 illustrates an example of operations of the functional modules for the centralized scheduling scheme using the COB of FIG. 2 according to the present invention, and FIG. 5 is a timing diagram illustrating the operation of the centralized scheduling scheme of FIG. 4. In FIG. 4, the operation of the functional modules for the centralized scheduling scheme based on the COB of FIG. 2 is illustrated. However, as described above, since the operation of each functional module is the same, the function modules of the HOB of FIG. It may also operate as shown in FIG.

Before describing FIG. 4 and FIG. 5, the operation of the MAC protocol of each of the EPON and WiMAX systems will be described.

Basically, EPON broadcasts all packets downstream to one or more ONUs based on time division multiplexing (TDM). On the upstream, on the other hand, EPON's MAC protocol is a responsive multi-point control protocol for arbitrating shared media using time-division access (TDMA) to avoid packet collisions by multiple ONUs attempting to transmit data. multi-point control protocol (MPCP) is used. For upstream bandwidth allocation, the OLT periodically selects ONUs so that one or more ONUs all have the opportunity to send a 'REPORT' message. The 'REPORT' message includes the size information of the packet waiting in the buffer when the corresponding ONU is selected by the OLT. When a REPORT message is received, the OLT grants bandwidth to the corresponding ONUs using the 'GATE Control' message according to the specified bandwidth allocation policy. While bandwidth grants are processed on an ONU basis, bandwidth requests managed by MPCP can be made with REPORT or GATE control messages per priority queue consisting of eight classes of servic (COS).

WiMAX MAC protocol, which is connection-oriented in all services, maps to a unique connection ID (CID). Thus, a bandwidth request is made for each connection, but can be used either on a Grant Per Subscriber (GPS) basis or on a Grant Per Connection (GPC) basis. On the subscriber terminal grant basis, the BS is granted bandwidth only when SS information is included, and the SS sends back the approved bandwidth to the corresponding connection. Therefore, the subscriber terminal approval base reduces the procedure overhead of the BS, but requires an intelligent subscriber (intelligent subscriber). In contrast, the connection grant base creates a higher processing overhead of the BS than the subscriber terminal grant base, but can relatively simplify the functionality of the subscriber station. In the present invention, in order to reduce the complexity in processing request and approval, it is assumed that the subscriber station approval scheme is applied to the WiMAX system.

WiMAX provides five QoS classes according to QoS parameters defined to perform packet scheduling for diversity of services. The five QoS classes are unsolicited grant service (UGS), real-time to poll service (rtPS), extended real-time to poll service (ertPS), and non-real time. Non-real-time to poll service (nrtPS), and best effort (BE). Unsolicited grant service (UGS) allows a fixed amount of bandwidth while the connection is maintained, so the BS does not require subscriber station election. In other words, bandwidth is fixed until the unsolicited approval service (UGS) connection is terminated. It provides a fixed bit rate (CBR) real time traffic such as E-1 / T-1 or VoIP without silence suppression. Real-time election service (rtPS) is designed for variable bit rate (VBR) real-time traffic such as MPEG video, and subscriber stations are elected at periodic intervals to request bandwidth. The extended real-time elective service (ertPS) compensates for the shortcomings of the unsolicited approval service (UGS) and the real-time elective service (rtPS), and is useful for VoIP service with silent section concealment. BE is not guaranteed for both delay and throughput in traffic.

The centralized scheduling scheme according to the present invention reduces the packet delay and data transmission time for the subscriber station as soon as data is requested. An important issue in the present invention is how efficiently data of WiMAX can be transferred to EPON's data flow within a fixed cycle time (CT) in an integrated system.

Of the three combined structures illustrated in FIG. 1, the IOB is a structure in which bandwidth request and grant operate independently. For example, data transfer from SS to ONU-BS and from ONU-BS to OLT may be made on a hop-by-hop basis in storage and forwarding schemes via independent scheduling techniques (IS). Can be. Since the SS and the ONU-BS and the OLT are physically separated structures, the ONU does not have any information on how much bandwidth is granted from the BS to the SS, and the BS is allocated to the ONU. It does not know internally how much OLT bandwidth has been reserved. Therefore, IOB is not suitable for the central scheduling scheme (CS) of the present invention.

Unlike the independent scheduling scheme (IS), the centralized scheduling scheme (CS) of the present invention, which operates extensively in OLT, is controlled from the subscriber station (SS) by controlling data transmission of WiMAX according to the cycle time (CT) of the EPON. Manage traffic to the OLT. For convenience of description, in FIG. 4 and FIG. 5, only an OLT connected to a COB together with two SSs is considered.

Hereinafter, the operation of the central scheduling scheme of FIGS. 4 and 5 will be described.

First, connection requests originating from various applications of subscriber station (SS) are based on bandwidth management table (BMT), WiMAX's five QoS classes: Unsolicited Acknowledgment Service (UGS), Real-time Election Service (rtPS), Extended Real-Time Election. Classified as service (ertPS), non real-time elective service (nrtPS), and best (BE) and collected at WiMAX request concentrator 310 via a bandwidth request message requesting to connect ONU 100 and BS 200. (S10).

Bandwidth requests collected for the five QoS classes are linearly mapped in a one-to-one fashion by the QoS mapper of the JC 300 and stored in the ONU queue 120 with the five priority queues of the EPON. After waiting until the next election period, the EPON REPORT generator 140 continuously transmits the 'REPORT' message upon the previously approved data transmission with the collected bandwidth request (S20).

If the OLT recognizes a 'REPORT' message sent with previously approved data, the OLT's bandwidth allocation module 810 allocates the bandwidth and sends a 'GATE' message to the COB that includes the actual value of the allocated bandwidth. (S30).

After a certain time, a 'GATE' message containing the approved bandwidth for the EPON's class of service arrives at the EPON authorization processor 320 of the JC 300 to determine the class of service of WiMAX corresponding to the EPON's QoS class. do. At the same time, the corresponding grant information is reached at the WiMAX uplink scheduler 210. With the bandwidth given for the COB, the WiMAX uplink scheduler 210 notifies the subscriber station SS of the approved bandwidth according to the bandwidth management table (BMT). The WiMAX grant generator 220 transmits the bandwidth for each subscriber station SS to the subscriber station SS together with the uplink MAP (UL-MAP) indicating the transmission time information (S40).

For uplink data transmission, data of various application programs executed in the subscriber station (SS) is classified and waited for five class of service for QoS. The subscriber station (SS) scheduler 740 determines the bandwidth and transmission time according to the service classes, together with the bandwidth allocated for the subscriber station (SS). At the determined transmission time, the subscriber station SS transmits the data buster to the packet reconstructor 230 of the COB via the air link (S50). Here, data bursts represent data arranged in the order in which data generated by various applications are designated according to QoS class by SS scheduler 740.

Data busters sorted according to QoS class from unsolicited grant service (UGS) to best (BE) by terminal (SS) scheduler 740 are scheduled to only reach COB. Through packet rebuild 230 and packet classifier 130, data bursts are classified into application-specific data, which are mapped by QoS mapper 330 to correspond to a plurality of priority queues in ONU queue 120. Are stored. The EPON ONU scheduler 110 transmits the bursts of data arranged in accordance with the QoS mapped at the scheduled time to the OLT (S60). In this case, the data burst transmitted to the OLT is composed of an Ethernet packet including a 'REPORT' message including a bandwidth request for the next data transmission. In conclusion, the data burst transmitted from the subscriber station SS is sent directly to the OLT with a minimized delay (e.g., transmitted in (k + 1) th frame) through the COB.

6 shows the delay time gain of the central scheduling scheme of the present invention compared to the existing independent scheduling scheme.

For convenience of description, in FIG. 6, link propagation delays on both the air link and the optical link and contention-based bandwidth allocation in the WiMAX system are omitted. Although FIG. 6 illustrates, as an example, a fixed cycle time (CT) and a frame size (FS) of 2 ms and 5 ms, respectively, this may be applied to a wide range of other cases. In addition, it is assumed that the subscriber station is polled per frame. In the central scheduling scheme (CS), packets are sent in independent scheduling scheme (IS) because data is transmitted immediately at the next cycle time (CT) (or frame) after the full bandwidth reservation made through SS and COB. It is sent earlier from the ONU-BS. However, in an independent scheduling technique (IS), a packet cannot be sent in the ONU until the next upcoming cycle time (CT) that includes a longer packet delay.

7 shows an element in which a packet delay occurs in the ONU.

Referring to FIG. 7, the packet delay in the EPON is represented by Equation 1 below.

은 패킷 도달과 ONU에 의해 보내지는 다음 요청 사이의 평균 시간(

)이다. 최대 선출 시간(

)는 수학식 2와 같이 계산 될수 있다.here

Is the average time between packet arrival and the next request sent by the ONU.

)to be. Maximum Election Time (

) Can be calculated as in Equation 2.

,

,

및

는 각각 ONU의 개수, 전송 윈도우(μs), 최대 전송 윈도우 크기(bytes), 및 EPON의 업링크 전송율(bps)을 나타낸다. 본 발명에서는 사이클 타임(CT)과 최대 선출 시간(

)이 고정된 것으로 가정한 것으로 설명한다. ONU의 대역폭 요청으로부터 OLT로부터의 대역폭 승인까지 시간 구간은 수학식 3으로 계산된다.here

,

,

And

Denotes the number of ONUs, the transmission window (µs), the maximum transmission window size (bytes), and the uplink transmission rate (bps) of the EPON, respectively. In the present invention, the cycle time (CT) and the maximum elective time (

Is assumed to be fixed. The time interval from the bandwidth request of the ONU to the bandwidth grant from the OLT is calculated by Equation 3.

는 패킷 도달 순간에 큐 사이즈이고,

는 새로운 패킷 도달 전에 요청되는 대기 승인 사이즈이다.

는 고정된 CT를 이용하는 것으로 가정하였으므로 CT가 단순화 될 수 있다. 결과적으로,

는

(부하가 작은 경우)및

(부하가 큰 경우)조건에서 OLT로부터 승인 이후 큐잉 지연을 고려함에 의해 도달되므로,

는 수학식 4에 의해 주어진다.here

Is the queue size at the moment of packet arrival,

Is the wait grant size requested before a new packet arrives.

Is assumed to use a fixed CT, so the CT can be simplified. As a result,

The

(If the load is small) and

Is reached by considering the queuing delay after approval from the OLT (if the load is large),

Is given by equation (4).

)는 수학식 5와 같이 쓰여진다.Computing the average packet delay of the subscriber station (SS) is because all delay factors are derived by equations (1) through (4) because WiMAX uses similar election techniques for bandwidth allocation. However, the maximum transmission window size of the subscriber terminal (

) Is written as in Equation 5.

,

,

,

및

는 각각 전체 FS에 대한 업링크 서브프레임의 비율, 정렬 윈도우 크기 및 경합 윈도우 크기, WiMAX의 업링크 전송율 및 BS내의 SS의 개수를 나타낸다. 도 6 및 수학식 1 내지 4로부터 CS의 평균 패킷 지연(

)이 수학식 6과 같이 계산된다.here

,

,

,

And

Denotes the ratio of uplink subframes to total FS, alignment window size and contention window size, uplink rate of WiMAX and the number of SSs in BS, respectively. 6 and the average packet delay of CS from Equations 1 to 4

) Is calculated as in Equation 6.

)이 수학식 7과 같이 된다.And the average packet delay of the IS (

) Becomes as shown in equation (7).

)은 수학식 8과 같이 계산된다.From Equations 6 and 7, the delay gain from IS to IS

) Is calculated as in Equation 8.

Hereinafter, a simulation comparing the central scheduling scheme CS according to the present invention with the existing independent scheduling scheme IS will be described.

As described above, since HOB and COB are functionally equivalent to each other, only the centralized scheduling scheme (CS) uses the HOB and the independent scheduling scheme (IS) uses the IOB. In addition, the modeled wire-wireless integrated system consists of one OLT, 16 ONU-BSs, and 10 subscriber stations (SSs) per ONU-BS. Based on the structure widely used in EPON and WiMAX, the simulation parameters are calculated as the optical line connected at 1 Gbps in the EPON system with a distance of 20 km between the OLT and the divider and a distance of 5 km between the divider and ONU-BS. . In addition, the guard time between adjacent time slots is 1 μs, and the cycle time (CT) of the EPON is set to 1 or 2 ms. ONU has an ONU queue of size limited to 10 Mbytes. In WiMAX systems, the channel bandwidth and sampling factor are 20 MHz and 144/255, respectively. The frame size (FS) can vary between 5, 10 and 20 ms and the OFDMA symbol duration is 50 μs. The duty ratio of the downlink and uplink subframes is set to 7: 3. Modulation and Coding Technique (MCS) is selected from QPSK, 16-QAM and 64-QAM. The load sent to the subscriber station SS is normalized to 0 and 1 corresponding to 0 to 1 Gbps. Packets arrive at a Poisson distribution ratio, and Ethernet packets are evenly distributed from 64 to 1518 bytes.

The simulation analyzes the efficiency of the central scheduling scheme (CS) compared to the independent scheduling scheme (IS) according to various cycle times (CT) and frame size (FS), and the queuing delay in the subscriber station (SS), SS (SS) Compare the link throughput at the ETE end-to-end delay and the point between the OLT and the splitter.

8 and 9 illustrate average queuing delays in a centralized scheduling scheme and an independent scheduling scheme.

8 illustrates an average queuing delay in the subscriber station SS when the cycle time CT is 1 ms. As shown, the average queuing delay increases linearly with the load. However, it rises sharply at a certain point except when the frame size (FS) is 5 ms, and remains fixed again when the system is overloaded. The longer the frame size (FS) of WiMAX, the higher the queuing delay. This is because the period of opportunity for providing a packet in the subscriber station SS can be reduced by increasing the frame size FS. In addition, the graph of the central scheduling scheme (CS) differs significantly from the independent scheduling scheme (IS) at every frame size (FS). Such a difference is due to an efficient centralized scheduling technique (CS) that reduces bandwidth reservation time and sends data immediately upon bandwidth request for a subscriber station (SS). Similarly, even when the cycle time CT = 2ms, the average delay according to the frame size FS increases as shown in FIG. 9. However, while the graph slope of the central scheduling scheme (CS) increases more rapidly than in the case of the cycle time (CT) = 1, there is almost no difference in any cycle time (CT) in the independent scheduling technique (IS). This indicates that the central scheduling technique (CS) is more sensitive than the independent scheduling technique (IS) to changes in EPON's cycle time (CT). In the independent scheduling scheme (IS), data is transmitted from the subscriber station (SS) to the ONU-BS independently of the EPCP MPCP. Significant impact on approval. In particular, the gain of the average queuing delay of the centralized scheduling scheme (CS) compared to the independent scheduling scheme (IS) is greatly reduced when the load is large with the frame size (FS).

10 and 11 illustrate average ETE delays in a centralized scheduling scheme and an independent scheduling scheme (IS).

10 shows the average ETE delay when the cycle time CT is 1 ms. Similar to FIG. 8, the average ETE delay increases with the frame size FS for both the independent scheduling technique (IS) and the centralized scheduling technique (CS). However, the average ETE delay margin between the centralized scheduling technique (CS) and the independent scheduling technique (IS) is slightly higher than the average queuing margin at the subscriber station (SS) when the cycle time (CT) is 1 ms. This is because the independent scheduling scheme (IS) has a longer packet queuing delay than the central scheduling scheme (CS) as data is transmitted through the ONU-BS buffer. For example, an independent scheduling scheme (IS) requires two steps of bandwidth reservation processing in a storage and forward manner in order to transmit data from the SS to the OLT. That is, when data is transmitted from the subscriber station SS to the ONU-BS, the queue cannot be left until the reception of the next cycle GATE message for delivering the data, so the data transmitted from the subscriber station SS is stored in the ONU-BS. It is stored relatively long in the ONU queue. In comparison, the centralized scheduling technique (CS) can transmit data in the next cycle, thereby allowing a shorter queuing delay of the data. 11 shows the average ETE delay along with the frame size FS when the cycle time CT is two. As shown in Fig. 11, the average ETE delay is similar to that of Fig. 9 without additional delay by packets queued to the ONU-BS. In addition to increasing the cycle time CT, the delay gain of the centralized scheduling technique CS compared to the independent scheduling technique IS is significantly reduced with the frame size FS when the cycle time CT is 1 ms. .

12 and 13 show average throughput in the centralized scheduling scheme and the independent scheduling scheme.

12 shows the average throughput when the cycle time CT is 1 ms. Like the average ETE delay, throughput in Independent Scheduling (IS) increases linearly with the load provided up to the threshold (saturation point), and then almost fixedly upon reaching a certain value according to the frame size (FS). maintain. The throughput of the centralized scheduling scheme (CS) is higher than the independent scheduling scheme (IS) in all cases of frame size (FS), such as the trend of the average ETE delay at 1 ms. This shows that the central scheduling scheme (CS) in the HOB is efficient by reducing the bandwidth reservation time and enabling immediate data transmission of the ONU-BS. Therefore, it can be seen that the performance of the central scheduling scheme (CS) is improved compared to the independent scheduling scheme (IS). 13 can also be seen in a similar graph.

From the above, it can be seen that the change in the frame size (FS) of WiMAX affects the queuing delay of the subscriber station (SS) in both the central scheduling scheme (CS) and the independent scheduling scheme (IS). In general, shorter frame sizes (FS) in the electorate system provide better delay performance. In an independent scheduling scheme (IS), since EPON and WiMAX operate separately with their respective communication protocols, the EPON's cycle time (CT) does not affect the queuing delay of the subscriber station (SS). However, in the central scheduling scheme CS that reserves bandwidth from the subscriber station SS to the OLT, the queuing delay depends on the cycle time CT. This makes a performance difference between the centralized scheduling technique (CS) and the independent scheduling technique (IS) as the cycle time (CT) changes. Thus, the effect of cycle time (CT) on the ETE delays for independent scheduling (IS) and centralized scheduling (CS) can be neglected. In the present invention, since the scale of the frame size FS is much larger than the scale of the cycle time CT, the probability that the ONU-BS queue is full can be very low, and consequently has a small effect on the ETE delay.

14 and 15 show an average ETE delay and a maximum ETE delay.

14 and 15 show how the central scheduling scheme CS affects the ETE QoS under the condition that the cycle time CT is 2 ms and the frame size FS is 5 ms. 14 and 15, the maximum performance is set in both EPON and WiMAX. Traffic generated from SS is set to 10% of unsolicited approval service (UGS), 20% of real time elected service (rtPS), and 70% of best service (BE). The real time elected service (rtPS) and the best (BE) include extended real time elected service (ertPS) and non real time elected service (nrtPS), respectively, and QoS between EPON and WiMAX is simply mapped in a 1: 1 manner. Assume that 14 shows average ETE delays for unsolicited approval service (UGS), real time elected service (rtPS) and best effort (BE). In any case, the graph of the centralized scheduling technique (CS) lies below the graph of the independent scheduling technique (IS). In particular, the delay gain of the central scheduling scheme (CS) for the independent scheduling scheme (IS) increases sufficiently as a priority reduction of the service (eg, from Unsolicited Approval Service (UGS) to Best (BE)). Also, as shown in FIG. 15, the difference is greater depending on the load supplied at the maximum ETE delay. This indicates that services that allow centralized scheduling techniques (CS) have a relatively lower priority than QoS.

16 shows the average throughput from distributor to OLT.

The average throughput gain of the Centralized Scheduling Scheme (CS) over the Independent Scheduling Scheme (IS) is higher as shown in FIG. 16 according to Unsolicited Acknowledgment Service (UGS), Real Time Election Service (rtPS) and Best Practice (BE). appear. This is because HOB-based centralized scheduling scheme (CS) shares state information of bandwidth request, grant and QoS mapping, thus achieving better ETE QoS than independent scheduling scheme (IS).

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is evident that many alternatives, modifications and variations will be apparent to those skilled in the art.

Therefore, the true technical protection scope of the present invention will be defined by the technical spirit of the appended claims.

Claims (19)

EPON with one or more optical termination units (hereinafter referred to as ONU), WiMAX with one or more base stations and a plurality of subscriber stations, and a joint controller (JC) for connecting the ONU and the base station corresponding to the ONU. In the wire-wireless network integration method comprising:
A bandwidth request message requesting bandwidth for data transmission from one or more subscriber stations of the plurality of subscriber stations is transmitted to the JC through a corresponding base station of the one or more base stations;
When a previously approved data is sent from the ONU to a circuit terminal (hereinafter OLT) of EPON, the bandwidth request message is sent as a REPORT message along with the previously approved data;
Transmitting a GATE message including bandwidth information approved by the OLT in response to the REPORT message to the JC and the base station through the ONU;
Transmitting the approved bandwidth with the transmission time to the subscriber station in response to the GATE message sent to the JC and the base station; And
Transmitting data from the subscriber station to the OLT through the base station and the ONU at the transmission time. A computer-readable recording medium having recorded thereon program instructions for operating the wire-wireless network integration method according to claim 1. A wire-wireless network integration system for connecting a wired network EPON and a wireless network WiMAX using the wire-wireless network integration method according to claim 1. EPON with one or more optical termination units (hereinafter referred to as ONU), WiMAX with one or more base stations and a plurality of subscriber stations, and a joint controller (JC) for connecting the ONU and the base station corresponding to the ONU. In the wire-wireless network integration method comprising:
A bandwidth request message requesting bandwidth for data transmission from one or more subscriber stations of the plurality of subscriber stations is transmitted to the JC through a corresponding base station of the one or more base stations;
When the bandwidth request message is classified and stored according to the class of service, and previously approved data is transmitted from the ONU to the circuit terminal of the EPON (hereinafter OLT), the bandwidth request message is classified and stored together with the previously approved data. Transmitted as a REPORT message;
Transmitting a GATE message including bandwidth information approved by the OLT in response to the REPORT message to the JC and the base station through the ONU;
Transmitting the approved bandwidth with the transmission time to the subscriber station in response to the GATE message sent to the JC and the base station; And
Transmitting data from the subscriber station to the OLT through the base station and the ONU at the transmission time. The method of claim 4, wherein the step of sending to the JC
Generating a bandwidth request message by classifying bandwidth requests generated by one or more application programs of each of the plurality of subscriber stations according to a class designated in the WiMAX; And
And collecting the bandwidth request message from the plurality of subscriber stations to the JC. The method of claim 5, wherein the step of transmitting with the previously approved data is
The collected bandwidth request message is mapped to the corresponding class of the QoS class of EPON by the QoS mapper of the JC, and stored in the priority queue corresponding to the mapped class among the plurality of priority queues of the ONU. ; And
And the collected bandwidth request message is connected to the previously approved data and transmitted to the OLT as the REPORT message. The method of claim 6, wherein the step of transmitting to the JC and the base station
Analyzing the REPORT message sent to the OLT;
A bandwidth corresponding to each of the bandwidth request messages is allocated by the bandwidth allocation module of the OLT according to the analyzed REPORT message, and generating the GATE message including an actual value of the allocated bandwidth; And
And transmitting the GATE message to the JC and the base station. 8. The method of claim 7, wherein the step of transmitting to the subscriber station
Determining a service class of the WiMAX corresponding to the QoS class of the EPON in the JC in response to the GAGE message; And
And determining, by the WiMAX uplink scheduler of the base station, the transmission time according to a bandwidth management table. The method of claim 8, wherein the step of transmitting to the OLT
Arranging data generated in the one or more application programs of each of the subscriber stations according to the service class and sorted in a designated order;
Determining a bandwidth and a transmission time of a subscriber station by a scheduler of the terminal according to the bandwidth and the transmission time applied by the WiMAX scheduler;
Transmitting the sorted and sorted data to the base station at the transmission time of the subscriber station with the bandwidth of the subscriber station; And
And transmitting the data applied to the base station to the OLT. The method of claim 9, wherein the data is sent to the OLT
Classifying the data according to an application program by the packet reconstructor of the base station and the packet canceler of the ONU;
Mapped by the QoS mapper to a corresponding rank among the QoS ranks of the EPON and stored in the priority queue corresponding to the mapped rank among a plurality of priority queues of the ONU; And
And transmitting the data stored in the priority queue to the OLT at a time designated by the ONU scheduler of the ONU together with the REPORT message for the next data transmission. A computer-readable recording medium having recorded thereon program instructions for driving the wire-wireless network integration method according to any one of claims 4 to 10. A wired-wireless network integration system for connecting a wired network, EPON, and a wireless network, WiMAX, using the wired-wireless network integration method according to any one of claims 4 to 10. WiMAX having one or more base stations receiving bandwidth requests and data for data transmission from one or more subscriber stations of the plurality of subscriber stations;
An EPON having one or more optical termination devices (hereinafter ONUs) for transmitting a bandwidth request message to the OLT as a REPORT message together with the data previously approved at a circuit terminal (hereinafter OLT); And
Collect the bandwidth request applied to the base station to generate the bandwidth request message and store the bandwidth request message in the ONU, and the bandwidth information included in the GATE message transmitted in response to the bandwidth request message from the OLT to the one or more base stations; Wire-wireless network integration system having a joint controller (hereinafter referred to as JC) for transmitting to the one or more subscriber stations via. The method of claim 13, wherein each of the plurality of terminals
Wire-wireless network integration, characterized in that the data generated from a plurality of applications are classified into the data having a WiMAX service class according to the bandwidth management table, and generates a plurality of different bandwidth requests according to the service class of the data. system. The method of claim 14, wherein the JC is
A WiMAX request concentrator for collecting the plurality of bandwidth requests classified by the WiMAX service class;
An EPON grant processor that allocates a bandwidth in the EPON for the data according to bandwidth information included in the GATE message; And
And a QoS mapper which maps the collected plurality of bandwidth requests to the QoS class of the EPON and maps the bandwidths approved by the QoS class in the QoS grant processor to the WiMAX service class. Integrated system. The method of claim 15, wherein the base station
A WiMAX uplink scheduler for determining the approved bandwidth and transmission time and transmitting the determined bandwidth to the plurality of subscriber stations;
A grant generator for notifying each subscriber station of the actual amount of the bandwidth granted to each of the plurality of subscriber stations; And
And a packet reconstructor configured to receive the data generated by the applications of the plurality of subscriber stations and reconstruct the data into an easily transmitted form. The method of claim 16, wherein the ONU is
An ONU scheduler for transmitting the data to the OLT at a designated time;
An ONU queue having a plurality of priority queues, wherein the data and the bandwidth request message are temporarily stored in a corresponding priority queue according to the QoS class;
A packet classifier configured to classify the data applied from the base station and the bandwidth request message according to the QoS level and store the data in the corresponding priority queue; And
And a REPORT generator for generating the REPORT message using the data stored in the priority queue and the bandwidth request message and transmitting the REPORT message to the ONU scheduler. The method of claim 17, wherein the plurality of subscriber stations
And transmit the data at a specified bandwidth at a transmission time designated by the WiMAX uplink scheduler. The system of claim 13, wherein the base station, the ONU, and the JC are implemented as one integrated device.

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