KR100788900B1 - Apparatus and method for uplink scheduling in wideband wireless access system - Google Patents

Abstract

An uplink scheduling method in a broadband wireless access system and a device thereof are provided to improve an increase of a signaling section for offering bandwidth allocation opportunities to each terminal, and to enable the terminals to share radio resources used for uplink bandwidth requests, so as to cut down the radio resources, thereby improving an overall system throughput. Subscriber terminals are registered in operation polling code groups or virtual polling code groups(S20). A base station searches polling periods of the operation polling code groups in every frame to retrieve operation polling code groups which have to allocate polls(S21). The base station generates CDMA(Code Division Multiple Access) group poll IEs(Information Elements) including bandwidth request location information and polling code group identifiers(S22). The generated IEs are simultaneously transmitted to all of the registered terminals(S23). The base station receiving orthogonal codes allocates radio resources to the terminals(S24).

Description

Apparatus and method for uplink scheduling in wideband wireless access system}

1 is a block diagram showing a data frame structure of a broadband wireless access system according to the prior art.

2 is a block diagram showing the configuration of a bandwidth request message of a broadband wireless access system according to the prior art.

3 is a flowchart illustrating a method for configuring a polling code group by a base station in a broadband wireless access system according to an exemplary embodiment of the present invention.

4 is a flowchart illustrating a method for allocating a poll to a subscriber station by a base station in a broadband wireless access system according to an exemplary embodiment of the present invention.

5 is a flowchart illustrating a method in which a subscriber station receives a polling code group identifier and a dedicated orthogonal code to which a subscriber station is registered in a broadband wireless access system according to an exemplary embodiment of the present invention.

6 is a flowchart illustrating a method in which a subscriber station receives a poll from a base station and performs a bandwidth request in a broadband wireless access system according to an embodiment of the present invention.

7 is a block diagram illustrating an uplink scheduling apparatus for managing bandwidth request poll / permission in a broadband wireless access system according to an embodiment of the present invention.

The present invention relates to an apparatus and method for uplink scheduling in a wideband wireless access system. In particular, the present invention relates to an uplink bandwidth request and a grant when providing a real-time or non-real-time polling service in a broadband wireless access system. The present invention relates to an uplink scheduling apparatus and a method for performing a polling process.

The broadband wireless access system refers to a next-generation communication method that further supports mobility in a short-range data communication method using a fixed access point, such as a conventional wireless local area network (LAN). Various standards for such a wireless broadband wireless access system have been proposed, and international standardization of a broadband wireless access system is currently progressing around the IEEE 802.16 standardization group.

On the other hand, the subscriber station and the base station of the broadband wireless access system performs communication by Orthogonal Frequency Division Multiple Access (hereinafter, referred to as "OFDMA"). The OFDMA scheme is a multiplexing scheme combining a frequency division scheme using a plurality of orthogonal frequency subcarriers as a plurality of subchannels and a time division scheme (TDM) scheme. The OFDMA scheme is inherently resistant to fading occurring in a multipath and has a high data rate.

Meanwhile, in a wireless system that provides various services using limited resources, a scheduling scheme for efficiently using resources is required. With this scheduling approach, ideally, it is possible to quickly reclaim unnecessary resources and reassign them for necessary services. In addition, by reducing the amount of information transmitted using radio resources, a method of using the surplus resources for other purposes should also be sought.

In the past, various uplink scheduling methods for broadband wireless access services have been proposed. Scheduling services are applied to improve the efficiency of the poll / permit process. By specifying a Quality of Service ("QoS") parameter associated with the scheduling service, the base station can anticipate the need for delay and throughput of upstream traffic, thus polling (band request) at an appropriate time. Opportunities) and permits. The service is divided into four classes according to the type of data flow.

Table 1 shows service classes classified according to QoS in a broadband wireless access system.

Table 1

As shown in Table 1 above, Unsolicited Guaranteed Service (UGS), Real-time Polling Servicce (RTPS), and non-real-time service depending on the service type. Polling Service (hereinafter referred to as "nrtPS") and finally Best Effort (hereinafter referred to as "BS") class, and the detailed characteristics of each service class are as follows.

UGS is designed to support traffic flows that occur periodically in fixed-size packets such as Voice over IP (VoIP). By providing fixed size slot allocation periodically, this service eliminates the delay and overhead of reservation request and authorization process, and proposes an allocation scheme that can satisfy the real-time requirements of the flow. The subscriber station receiving this service cannot make a reservation request through competition or a reservation request through piggyback according to the request / transmission policy, and the base station should not give a transmission opportunity for the reservation request to the terminal.

rtPS supports real-time traffic that periodically generates variable length data packets such as MPEG video. The service satisfies the real-time demand of the service flow by periodically providing a unicast band request opportunity to the corresponding terminal to request as much bandwidth as desired. Although more overhead is incurred than the above UGS service, it can support variable size bandwidth allocation for optimal data transmission efficiency. The base station provides a unicast poll request opportunity (cyclic broadcast poll) to the subscriber station receiving the service, the terminal can use only the request opportunity given by the set request / transmission policy and can not make a request through the competition. The main service information elements are the defined polling interval (nominal polling interval), the allowed polling jitter, and the request / transmission policy.

The nrtPS service is provided to support non real-time traffic flows that require a variable size Data Grant Burst Type, such as File Transfer Protocol (FTP), which requires high bandwidth. The base station properly provides a unicast poll, while the terminal may also make a competitive request when necessary. The main service parameters are the specified polling period, the reserved minimum traffic rate, request / transmission policy and traffic priority.

BE refers to a general best-effort service, the terminal receiving the service is mainly assigned to the slot by making a request by the competition, but can also respond to the voluntary slot allocation of the unicast poll and the base station. The key service parameters are the reserved minimum traffic rate, maximum allowed traffic rate, and traffic priority.

1 is a diagram illustrating a data frame structure of a broadband wireless access system.

As shown in FIG. 1, a downlink-map (DL-MAP) message defines a use allocated for each burst for a downlink period in a physical layer, and defines an uplink map (AP). The "UL-MAP") message defines the purpose of the allocated burst for the uplink period. The information element (hereinafter referred to as "IE") constituting the DL-MAP includes a downlink interval usage code (DIUC), a connection ID (CID), and position information of the burst (sub channel offset, symbol offset, subchannel number, symbol number). ), Whereby downlink traffic intervals are identified at the user end. On the other hand, the IE constituting the UL-MAP message is determined by the Uplink Interval Usage Code (UIUC) for each connection ID (CID), each interval is defined as a 'duration' defined in the UL-MAP IE from the previous IE start point Start at as far away as you can.

The base station uses the UL-MAP IE of the frame to assign a unicast poll to the subscriber station.

Table 2 shows UL-MAP IEs used to express poll allocation information in UL-MAP messages.

TABLE 2

One UL-MAP IE is used for one unicast poll assignment, and one UL-MAP IE requires 20 bits as shown in the above table.

2 illustrates a configuration of a bandwidth request (BR) message including bandwidth request information of a subscriber station. When the subscriber station desires to request its bandwidth, the subscriber station transmits the bandwidth request information in the BR message to the base station.

Meanwhile, the number of UL-MAP IEs used to represent unicast polls in the UL-MAP message is equal to the number of terminals requiring unicast polls in the corresponding frame. For example, if there are four polling service using subscriber stations having the same polling period to which the base station allocates polls, and these subscriber stations need to be assigned polls every i-th frame, the BR messages of the four subscriber stations collide in the radio interval. Should be sent without The base station forms a UL-MAP IE including resource allocation information of each subscriber station and transmits the UL-MAP IE to each terminal, and the subscriber station transmits bandwidth request information by using a band allocated through the UL-MAP IE in an uplink frame period. send.

In this case, the UL-MAP IE includes location information (duration) to which the corresponding terminal transmits the bandwidth request message and a CID which is a subscriber station identification code.

When the number of terminals requesting polling services such as rtPS and nrtPS services increases in a broadband wireless access system, the burden on unicast polls allocated periodically to provide bandwidth request opportunities to each terminal increases. This increases the number of UL-MAP IEs provided for poll allocation to each UE, thereby increasing the signaling interval (MAP area) occupied in the entire downlink frame, and consequently, wastes resources and reduces system yield.

In addition, unlike the rtPS service where periodic traffic is expected to occur, in the case of nrtPS service, when the base station cannot predict the situation of the subscriber station, when the time of occurrence of traffic (band request time) and the time of polling do not match (that is, If the band request information is not transmitted to the allocated area, the allocated resource may be wasted.

The technical problem to be achieved by the present invention is to improve the number of terminals requesting polling service in a broadband wireless access system to increase the signaling interval (UL-MAP) for providing bandwidth allocation opportunity to each terminal, and to improve the uplink bandwidth The present invention provides an uplink scheduling apparatus and method for improving overall system yield by reducing radio resources required for bandwidth requests by sharing radio resources required for a request.

In a broadband wireless access system according to an aspect of the present invention for achieving the above object, an uplink scheduling method in which a base station performs polling / permission for a bandwidth request for a polling service of a subscriber station is provided.

a) registering the subscriber station with a polling code group having the same polling period as the polling period of the polling service, where the polling period is a period where the base station provides an uplink bandwidth request opportunity to the subscriber station; And b) assigning a poll to a subscriber station registered to the polling code group corresponding to the polling period, where poll means bandwidth request opportunity.

In addition, the uplink scheduling method in which a subscriber station performs an uplink bandwidth request for a polling service to a base station in a broadband wireless access system according to another aspect of the present invention,

a) the subscriber station receiving information on a registered polling code group; b) being assigned a poll from the base station, where poll means bandwidth request opportunity; And c) when the poll includes a polling code group indicator corresponding to the polling code group, requesting an uplink bandwidth to the base station.

In addition, in a broadband wireless access system according to another aspect of the present invention, an uplink scheduling apparatus in which a base station performs polling / permission for a bandwidth request for a polling service of a subscriber station is provided.

A polling code group database for storing a polling period for each polling code group and terminal information registered in the polling code group; A service connection identifier for outputting a polling period and connection identification information corresponding to the polling service when the received service connection request is a polling service; Receiving the polling period and the connection identification information, register the subscriber station in the polling code group database, output the identifier of the polling code group registered by the subscriber station, and transfer the polling code group identifier to the subscriber station. A polling code group manager; And a poll allocation scheduler unit for allocating polls corresponding to polling periods of each polling code group for each polling code group stored in the polling code group database.

In addition, in a broadband wireless access system according to another aspect of the present invention, an uplink scheduling apparatus in which a subscriber station performs an uplink bandwidth request for a polling service to a base station,

A receiver configured to receive and output an identifier of a polling code group registered by the subscriber station from the base station; A band request code generator for calculating a size of a bandwidth required for transmitting uplink data and outputting a code corresponding to the bandwidth size; A bandwidth allocation scheduler for extracting and outputting band request code position information from the downlink data frame when the polling code group identifier is included in the downlink data frame received from the base station; And a bandwidth request unit for allocating the code received from the band request code generator to a band corresponding to the band request code location information received from the bandwidth allocation scheduler and transmitting the code to the base station.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art may easily implement the present invention. As those skilled in the art would realize, the described embodiments may be modified in various different ways, all without departing from the spirit or scope of the present invention. In the drawings, parts irrelevant to the description are omitted in order to clearly describe the present invention. Like parts are designated by like reference numerals throughout the specification.

Hereinafter, an uplink scheduling method applicable to a broadband wireless access system proposed by IEEE 802.16e will be described as an example, but the present invention is not necessarily limited thereto.

Now, in the following, the base station periodically allocates a unicast poll to a subscriber station providing a real-time or non-real-time polling service in a broadband wireless access system according to an embodiment of the present invention, thereby providing a bandwidth request opportunity to the terminal. The uplink scheduling method provided will be described with reference to the drawings.

First, referring to terms used to describe an embodiment of the present invention, a polling period is a value that is pre-negotiated between a subscriber station and a base station, and provides a subscriber station with an uplink bandwidth request opportunity (pol). Say the cycle. There are various ways to pre-negotiate the polling period between the subscriber station and the base station. When the base station attempts to connect a new service to the mobile station, the base station may be configured in a dynamic service addition (“DSA”). In some cases, the UE may notify the polling period. When the UE requests a new service from the UE, the UE transmits a polling period to the BS by including a polling period in a connection establishment (DSA-REQ / DSA-RSP) message during connection establishment. Can be informed. In addition, there is a method of providing a proper polling period according to the base station anticipates the processing rate of the service and the delay request of the uplink traffic, etc. One of the methods, the base station can recognize the polling period in advance.

In addition, in the broadband wireless access system according to an embodiment of the present invention, the polling code group is composed of an operating polling code group and a polling code group operating poll assignment for each actual polling code group, but the number of registered terminals does not exceed a predetermined number. It manages by dividing into a virtual polling code group that performs poll allocation for each terminal according to the method. The number of terminals constituting the polling code group is appropriately determined in consideration of the total number of orthogonal codes, the orthogonality of codes, the system load and the base station reception capability, and the minimum number of users (N _min ) corresponding to the system yield and capability. And the maximum allowed number of users (N _max ) are used as the criteria to classify the operation polling code group and the virtual polling code group.

That is, when the number of currently registered terminals is smaller than the minimum number of users (N _min ), the terminal is managed as a virtual polling code group and a unicast poll is allocated by using a separate UL-MAP IE for each terminal. On the other hand, if it is larger than the minimum number of users (N _min ) and smaller than the maximum number of users (N _max ), it is classified as a production polling code group and a poll is assigned to each polling code group simultaneously using only one IE (information element). . On the other hand, when a new terminal is added to the operating polling code group that is actually in operation and exceeds the maximum allowable number N _max , a new virtual polling code group is created to register and manage the newly added terminal.

3 and 4, the base station assigns a subscriber station that performs a polling service to a polling code group during a polling process (bandwidth request polling / permission process) described above, and a corresponding polling code according to a polling period. An uplink scheduling method for allocating polls into groups will be described in detail.

3 is a flowchart illustrating a procedure in which a base station allocates a polling code group for a new service connection request in a broadband wireless access system according to an exemplary embodiment of the present invention.

As shown in FIG. 3, when a new service connection request is generated from a base station or a subscriber station in a broadband wireless access system, the base station determines whether a new service is a polling service such as rtPS or nrtPS (S10).

If the new requested service is a polling service, the base station searches whether there is an operation polling code group having the same period as the polling period of the new polling service (S11). As a result of the search, if there is an operation polling code group having the same polling period, the base station determines whether the maximum allowed number of users (N _max ) is exceeded when registering a new terminal in the found operating polling code group (S12). If the number N _max is not exceeded, a new subscriber station is registered in the operation polling code group (S13). In this case, as a method of joining the subscriber station to the polling code group, a method of registering a connection identifier corresponding to a new service connection, that is, a CID, to the polling code group is used.

On the other hand, if there is no operational polling code group having the same polling period, or if a new terminal is added even if it exists, the base station is a polling code having the same polling period in the virtual polling code group when the number of registered terminals exceeds the maximum allowed user number. Search for the group (S14).

As a result, if there is a virtual polling code group having the same polling period, the base station adds the subscriber station to the virtual polling code group (S15). If the subscriber station is added and it is determined that the number of terminals registered in the virtual polling code group exceeds the minimum number of users (N _min ) (S16), the base station changes the virtual polling code group to the operational polling code group (S17). The method of separately assigning polls for each terminal is changed to be performed for each polling code group.

On the other hand, if there is no virtual polling code group having the same polling period, the base station generates a new virtual polling code group, and registers the subscriber station to the newly created virtual polling code group (S18).

After the subscriber station using the new service is registered in the operation polling code group or the virtual polling code group, the base station uses the polling code group id of the registered polling code group and the subscriber station to perform the bandwidth request. A dedicated orthogonal code (for example, a dedicated PN code) is allocated to the subscriber station (S19). In this case, the process of transmitting the polling code group identifier and the dedicated orthogonal code to the corresponding subscriber station is included in a new service connection establishment (DSA) process, and the polling code group identifier and the dedicated orthogonal code are transmitted and received during the connection establishment process. DSA-REQ / DSA-RSP) is transmitted to the terminal.

4 is a flowchart illustrating a method in which a base station allocates polls for each operation polling code group using cdmaGroupPoll_IE in a broadband wireless access system according to an embodiment of the present invention.

First, when a new polling service connection is requested, the subscriber station which performs a service according to the polling cycle of the corresponding service is registered in the operating polling code group or the virtual polling code group (S20). Thereafter, the subscriber station performs a bandwidth request according to a polling process performed for each polling code group when the polling code group registered with the subscriber station is the operational polling code group.

That is, the base station searches for polling periods of the operational polling code groups every frame to search for an operational polling code group at which it is time to allocate a poll (S21). If there is an operation polling code group to which a poll should be allocated in the current frame, the base station has a polling code group identifier to be transmitted to the polling code group and bandwidth request location information (duration) to be used for bandwidth requests by terminals belonging to the polling code group. The included cdmaGroupPoll_IE is generated (S22).

The generated cdmaGroupPoll_IE is simultaneously transmitted to all terminals registered in the operation polling code group included in the signaling period, that is, UL-MAP (S23).

Meanwhile, the terminal allocated the poll calculates the bandwidth required for uplink data transmission, allocates an orthogonal code corresponding to the bandwidth required for the bandwidth corresponding to the location information (duration) included in the cdmaGroupPoll_IE, and transmits it to the base station. Thereafter, the base station receiving the orthogonal code allocates radio resources to the corresponding terminal as much as the bandwidth corresponding to the received orthogonal code (S24).

In this case, cdmaGroupPoll_IE means a UL-MAP information element (IE) used for allocating polls to all terminals registered in one operation polling code group, and includes a polling code group identifier and bandwidth request location information (duration), etc. do.

Table 3 shows an example of the aforementioned cdmaGroupPoll_IE.

TABLE 3

According to Table 3, cdmaGroupPoll_IE includes Group ID instead of CID previously included to provide bandwidth request opportunity for each terminal, and all terminals registered in the polling code group share one bandwidth request location information (duration). Do it.

As described above, a method in which polling cycles of terminals having the same polling period are configured as a polling code group and allocating polls simultaneously to all the terminals registered in one polling code group using only one information element (cdmaGroupPoll_IE), has been previously performed. This has the effect of improving system yield compared to the method of assigning polls by setting -MAP IE.

In particular, the more polling terminals using the same polling period, the better performance is achieved, and when the number of terminals with the same polling period does not exceed a certain number of users, that is, the minimum number of users, the adaptive scheduling using the conventional method is used. Can be performed.

Hereinafter, a method of performing uplink scheduling for an uplink resource request using an orthogonal code allocated to each polling code group by a subscriber station will be described in detail with reference to the accompanying drawings.

FIG. 5 is a flowchart illustrating a procedure in which a subscriber station performing a polling service receives information on a polling code group in which it is registered and a dedicated orthogonal code in a broadband wireless access system according to an exemplary embodiment of the present invention.

First, when a new polling service connection is requested from a base station or a subscriber station (S30), the subscriber station receives a polling code group identifier registered with itself and a dedicated orthogonal code necessary for bandwidth request through a connection establishment message transmitted and received during the connection establishment process. (S31).

The subscriber station stores or stores the polling code group identifier and the dedicated orthogonal code thus received in memory (S32), and then uses the bandwidth request periodically according to the polling period.

Table 4 is an example of dedicated orthogonal codes assigned to each polling code group, and the same polling code group is identified by a polling code group identifier. In addition, UEs registered in the same polling code group may be assigned a unique orthogonal code set within the same group, and different polling code groups may include the same orthogonal code.

Table 4

Polling code group User (Connection ID) Request bandwidth size Assigned code index A Terminal # 1 6 bytes Ortho code A 1500 bytes Ortho code B Terminal # 2 6 bytes Ortho code C 2048 bytes Orthogonal Code D B Terminal # 3 600 bytes Ortho code A 5000bytes Ortho code B Terminal # 4 60 bytes Ortho code C 2048 bytes Orthogonal Code D C Terminal # 5 6 bytes Ortho code A 500 bytes Ortho code B Terminal # 6 6 bytes Ortho code C 100 bytes Orthogonal Code D

6 is a flowchart illustrating a polling process in which a subscriber station performing a polling service requests a bandwidth to a base station using a dedicated orthogonal code in a broadband wireless access system according to an exemplary embodiment of the present invention.

When the subscriber station receives the cdmaGroupPoll_IE from the base station (S40), it is checked whether the cdmaGroupPoll_IE includes the polling code group identifier to which it belongs (S41).

If the corresponding polling code group identifier is included, location information (duration) to transmit the band request code is detected from cdmaGroupPoll_IE (S42).

Subsequently, if there is uplink data to be transmitted to the base station (S43), the subscriber station calculates the bandwidth required for the corresponding uplink data transmission, and uses the dedicated orthogonal code received in the connection establishment process to scrambling the required bandwidth size. And transmits to the base station (S45).

At this time, all terminals belonging to one operation polling code group share one bandwidth request location information (duration) included in cdmaGroupPoll_IE and transmit an orthogonal code, and terminals registered to one operation polling code group are different dedicated orthogonal codes. By using the code, a bandwidth request can be made without collision between terminals. That is, even if the bandwidth request orthogonal codes are transmitted using the same band, it is possible to separate the corresponding codes from the base station because the codes are orthogonal to each other.

For example, referring to Table 4, when UE # 1 belonging to the operation polling code group A performs a bandwidth request using an orthogonal code, UE # 1 calculates a bandwidth required for uplink data transmission. If the required bandwidth is 6 bytes, the terminal # 1 transmits an orthogonal code A corresponding to 6 bytes to the base station.

Receiving the orthogonal code A, the base station searches for an operation polling code group in which terminal # 1 is registered. In this case, the base station manages the same orthogonal codes transmitted to the subscriber station for each operation polling code group, and is used to calculate the necessary bandwidth from the orthogonal codes received from the terminals.

That is, when the orthogonal code A is received, the terminal # 1 searches for the registered operation polling code group, searches for the same code as the orthogonal code A among the orthogonal codes of the corresponding operation polling code group, and according to the search result, the corresponding terminal receives 6 bytes. Recognizing that the bandwidth of needs to be allocated to the terminal # 1 bandwidth of 6 bytes.

As described above, a method for performing a bandwidth request by sharing an band with multiple terminals and transmitting an orthogonal code for a bandwidth request is performed by the base station even if several terminals transmit the band request code using the same resource because of orthogonality between codes. Since each code is detectable, code multiplexing gains result in an improved system yield.

Particularly, in case of nrtPS, when polling is allocated for each polling code group and shared one band is used, another UE belonging to the same polling code group does not perform bandwidth request because there is no uplink traffic. Since the terminals are still likely to use the allocated area, the possibility of wasting resources is reduced by that much.

7 illustrates an uplink scheduling apparatus for performing a bandwidth request poll / license process, that is, a polling process, in a broadband wireless access system according to an embodiment of the present invention.

As shown in FIG. 7, the uplink scheduling apparatus for performing a polling process in the base station 10 includes a polling code group database 110, an orthogonal code database 120, a service connection identification unit 130, and a polling code group management unit. 140, an orthogonal code manager 150, a poll allocation scheduler 160, and a bandwidth allocator 170.

The polling code group database 110 classifies a polling code group composed of terminals having the same polling period into an operating polling code group and a virtual polling code group according to the number of registered terminals, and includes a polling period corresponding to each polling code group. Registered terminal information is stored.

The orthogonal code database 120 classifies and stores dedicated orthogonal codes allocated to each polling code group once again for each terminal registered in the corresponding polling code group. In this case, orthogonal codes allocated to all terminals in the same polling code group should have a different mode, and may use the same orthogonal code between different polling code groups.

When a new service connection is requested from the base station or the subscriber station, the service connection identification unit 130 receives information on the corresponding service and distinguishes whether the new service is a polling service, and if the polling service is a polling service, determines the polling period and the CID corresponding to the service. Calculate and output

The polling code group manager 140 receives a polling period and a CID from the service connection identifier 130. Thereafter, the polling code group manager 140 searches the polling code group database 110 for an operation polling code group or a virtual polling code group having the same polling period as the received polling period and registers the CID to perform a corresponding service. Register the subscriber station to the polling code group. If there is no polling code group found, a new virtual polling code group is created and the subscriber station is registered in the generated virtual polling code group. In addition, the polling code group manager 140 also manages the polling code group database 110 and transmits the polling code group identifier registered by the subscriber station to the terminal through a connection establishment message transmitted and received during a service connection establishment process. It also plays a role.

The orthogonal code manager 150 receives the CID from the service connection identification unit 130 and generates a dedicated orthogonal code to be transmitted to the subscriber station 20. The generated orthogonal code is included in the connection establishment message transmitted and received during the service connection establishment process together with the identifier of the polling code group and transmitted to the subscriber station 20. Meanwhile, the generated orthogonal codes generated as described above are classified by polling code groups and stored in the orthogonal code database 120 together with the bandwidth information indicated by the orthogonal codes.

The poll allocation scheduler 160 performs a role of allocating polls to terminals registered to the operation polling code group, which is the poll allocation time, in accordance with the polling period of the operation polling code groups stored in the polling code group database 110. do. To perform poll allocation as described above, the poll allocation scheduler 160 includes a cdmaGroupPoll_IE including a polling code group identifier and bandwidth request code location information in a UL-MAP and transmits the same. On the other hand, the base station does not manage the poll allocation for the terminals belonging to the virtual polling code group for each group, and manages the poll allocation for each terminal separately according to the conventional method.

On the other hand, the base station 10 receives the orthogonal code corresponding to the uplink bandwidth request from the subscriber station 20 has been assigned a poll, in response to the orthogonal code received from the terminal 20 through the bandwidth allocation unit 170 The bandwidth information required by the subscriber station 20 is obtained from the orthogonal code database 120 and the bandwidth is allocated to the corresponding device 20.

Meanwhile, as shown in FIG. 7, the uplink scheduling apparatus of the subscriber station 20 generates an orthogonal code database 210, a receiver 220, a bandwidth allocation scheduler 230, and a band request code to perform a polling process. The unit 240 and the bandwidth request unit 250 is included.

The orthogonal code database 210 stores the polling code group identifier and the dedicated orthogonal codes received from the base station 10. At this time, the received orthogonal codes are classified and stored according to the bandwidth required by the subscriber station 20.

The receiver 220 receives the polling code group identifier and the dedicated orthogonal codes corresponding to the service provided by the subscriber station 20 from the base station 10 and stores them in the orthogonal code database 210.

When the bandwidth allocation scheduler 230 receives the data frame including the cdmaGroupPoll_IE from the base station 10, the bandwidth allocation scheduler 230 checks whether the cdmaGroupPoll_IE includes the identifier of the polling code group to which the subscriber station 20 belongs, and if so, the cdmaGroupPoll_IE The bandwidth request code position information included in the detected bandwidth is output to the bandwidth requester 250. In addition, the bandwidth allocation scheduler 230 controls the bandwidth request code generation unit 240 to read an orthogonal code corresponding to a bandwidth required for transmitting uplink data from the orthogonal code database 210.

The bandwidth request code generation unit 240 calculates a bandwidth required for uplink traffic when a request is made from the bandwidth allocation scheduler 230, and reads an orthogonal code corresponding thereto from the orthogonal code database 210.

The orthogonal code set as described above is allocated to a band corresponding to band request code position information received from the bandwidth allocation scheduler 230 in the bandwidth requesting unit 250 and transmitted to the base station 10.

Hereinafter, an uplink scheduling method in which an uplink scheduling apparatus of a base station 10 and a subscriber station 20 performs a polling process for uplink bandwidth request and grant in a broadband wireless access system according to an exemplary embodiment of the present invention. do.

First, the base station 10 confirms that a new polling service connection is requested through the service connection identification unit 130 and extracts a CID and a polling period of the subscriber station 20 performing the new polling service.

The polling period and the CID are transmitted to the polling code group manager 140 and the orthogonal code manager 150, and the polling code group manager 140 polls the polling code group having the same polling period as the polling period. Search in database 110. If there is an operational polling code group or a virtual polling code group having the same polling period, the polling code group manager 140 registers the received CID in the corresponding polling code group and there is no polling code group having the same polling period. In this case, a new virtual polling code group is created to register the CID.

The polling code group manager 140 transmits the identifier of the polling code group in which the CID of the terminal is registered to the orthogonal code manager 150, and the orthogonal code manager 150 is dedicated to the subscriber station 20 corresponding to the CID. Assign an orthogonal code. In addition, the dedicated orthogonal code newly assigned to the subscriber station 20 is stored in the orthogonal code database 120 by the base station 10 and separately managed according to the polling code group and the terminal information.

On the other hand, the subscriber station 20 has been assigned a dedicated orthogonal code through a connection setup message from the orthogonal code management unit 150 of the base station 10 receives a dedicated orthogonal code through the receiver 220 to the orthogonal code database 210. Store the corresponding orthogonal codes. The stored orthogonal codes are then used when the subscriber station 20 requests uplink bandwidth to the base station during the polling process.

After the polling code group registration and the dedicated orthogonal code allocation to the subscriber station 20 are completed for the new service, the base station 10 is classified into an operation polling code group and a virtual polling code group according to the number of terminals registered in the polling code group. In order to manage the poll allocation process, in the case of an operation polling code group, polls are allocated to all registered terminals according to a corresponding polling period at a time.

That is, when the polling period of the operational polling code group to which the subscriber station 20 belongs has elapsed and the poll allocation time has elapsed, the poll assignment scheduler 160 of the base station sends the corresponding polling code group identifier and the band request to the subscriber station 20. The cdmaGroupPoll_IE including the code location information is included in the UL-MAP and transmitted.

Meanwhile, the bandwidth allocation scheduler 230 of the subscriber station 20 receiving the cdmaGroupPoll_IE checks whether the received cdmaGroupPoll_IE includes the polling code group identifier to which it belongs, and if so, detects the bandwidth request code location information from the cdmaGroupPoll_IE. And outputting, and requests the orthogonal code generation to the band request code generation unit 240.

The band request code generator 240, which has been requested to generate an orthogonal code, calculates a bandwidth required for uplink traffic and obtains an orthogonal code corresponding to the required bandwidth from the orthogonal code database 210. The orthogonal code thus calculated is allocated to a band corresponding to the band request code location information detected by cdmaGroupPoll_IE by the bandwidth requesting unit 250 and received by the base station 10.

As such, the base station 10 receiving the orthogonal code from the subscriber station 20 reads the bandwidth information corresponding to the orthogonal code from the orthogonal code database 120 through the bandwidth allocator 170 and needs the subscriber station 20. Allocates an uplink bandwidth.

The uplink scheduling method and apparatus for managing uplink bandwidth requests and grants in a broadband wireless access system according to an embodiment of the present invention is different from the conventional UL-MAP IE for each UE for allocating polls. In addition, since a polling code group having the same polling period is configured to allocate a poll using only one information element, that is, one cdmaGroupPoll_IE for each polling code group, the size of UL-MAP can be reduced. In addition, multiple UEs belonging to one polling code group share one code region and perform a band request using an orthogonal code, thereby improving system yield by reducing an uplink signaling region used for a bandwidth request of the UE. Has the effect of

Particularly, in case of nrtPS, when polling is allocated for each polling code group and shared one band is used, another UE belonging to the same polling code group does not perform bandwidth request because there is no uplink traffic. Since the terminals are still likely to use the allocated area, the possibility of wasting resources is reduced by that much.

Although the embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto, and various modifications and improvements of those skilled in the art using the basic concepts of the present invention defined in the following claims are also provided. It belongs to the scope of rights.

The uplink scheduling method and apparatus for managing uplink bandwidth request and grant in the broadband wireless access system according to an embodiment of the present invention are the same as that of using one UL-MAP IE per terminal to allocate a poll. By configuring a polling code group having a polling period and assigning a poll using only one information element, that is, one cdmaGroupPoll_IE, for each polling code group, the size of UL-MAP can be reduced. In addition, multiple UEs belonging to one polling code group share one code region and perform a band request using an orthogonal code, thereby improving system yield by reducing an uplink signaling region used for a bandwidth request of the UE. Has the effect of

In addition, in case of nrtPS, when terminals registered to a polling code group share a band and make a bandwidth request through an orthogonal code, other terminals belonging to the same group may be configured even if the terminal does not perform the bandwidth request because there is no uplink traffic. Since the UEs still have sufficient possibility of using the allocated area, there is an effect of preventing waste of radio resources.

Claims (19)

An uplink scheduling method in which a base station performs poll / license for a bandwidth request for a polling service of a subscriber station in a broadband wireless access system, a) registering the subscriber station with a polling code group having the same polling period as the polling period of the polling service, where the polling period is a period where the base station provides an uplink bandwidth request opportunity to the subscriber station; And b) allocating polls to subscriber stations registered to the polling code group corresponding to the polling period, where poll means bandwidth request opportunity; Uplink scheduling method comprising a. The method of claim 1, Step a) is If there is no polling code group having the same polling period as the polling service, generating a new polling code group having a polling period of the polling service; And Registering the subscriber station with the newly generated polling code group Uplink scheduling method comprising a. The method according to claim 1 or 2, Between step a) and step b), Allocating a dedicated orthogonal code to the subscriber station More, After step b), Receiving an orthogonal code from the subscriber station and allocating an uplink bandwidth to the subscriber station in response to the received orthogonal code; Uplink scheduling method characterized in that it further comprises The method of claim 3, wherein The dedicated orthogonal code is, Orthogonal code corresponding to the uplink bandwidth of the subscriber station, the uplink scheduling method, characterized in that unique in the polling code group. The method of claim 3, wherein The uplink scheduling method according to claim 1, wherein the dedicated orthogonal code is allocated to the subscriber station through a connection setup message transmitted and received during the service connection setup process between the base station and the subscriber station. The method of claim 1, In step b), When the subscriber station is registered in the polling code group registered terminal number is included in the first range, the polling is assigned to all the terminals registered to the polling code group using only one uplink map information element Uplink scheduling method. The method of claim 6, The first range is, The uplink scheduling method characterized in that the value is determined by the uplink reception capability of the base station, the total number of orthogonal codes and orthogonality of the code. The method of claim 6, The uplink map information element includes an indicator of the polling code group and bandwidth request code location information. An uplink scheduling method in which a subscriber station performs an uplink bandwidth request for a polling service to a base station in a broadband wireless access system, a) the subscriber station receiving information on a registered polling code group; b) being assigned a poll from the base station, where poll means bandwidth request opportunity; And c) when the poll includes a polling code group indicator corresponding to the polling code group, requesting an uplink bandwidth to the base station Uplink scheduling method comprising a. The method of claim 9, Step a) is Receiving a dedicated orthogonal code from the base station, In step c), The uplink scheduling method of claim 1, wherein the uplink bandwidth is requested to the base station using the dedicated orthogonal code. The method of claim 10, And the polling code group indicator and the dedicated orthogonal code are included in a connection establishment message transmitted and received during a connection establishment process between the base station and the subscriber station. The method of claim 10, The poll is allocated using an uplink map information element, and the uplink map information element includes a polling code group indicator and band request code location information. The method of claim 12, And requesting an uplink bandwidth by allocating an orthogonal code corresponding to a band required for uplink data transmission among the dedicated orthogonal codes to a band corresponding to the band request code location information. The method of claim 10, The dedicated orthogonal code is, Orthogonal code corresponding to the uplink bandwidth of the subscriber station, the uplink scheduling method, characterized in that unique in the polling code group. An uplink scheduling apparatus in which a base station performs poll / license for a bandwidth request for a polling service of a subscriber station in a broadband wireless access system, A polling code group database for storing a polling period for each polling code group and terminal information registered in the polling code group; A service connection identifier for outputting a polling period and connection identification information corresponding to the polling service when the received service connection request is a polling service; Receiving the polling period and the connection identification information, register the subscriber station in the polling code group database, output the identifier of the polling code group registered by the subscriber station, and transfer the polling code group identifier to the subscriber station. A polling code group manager; And The poll allocation scheduler unit for allocating polls corresponding to polling cycles of each polling code group for each polling code group stored in the polling code group database. Uplink scheduling apparatus comprising a. The method of claim 15, An orthogonal code database for storing a dedicated orthogonal code allocated to each polling code group and a bandwidth size corresponding to the dedicated orthogonal code; And Receiving the connection identification information and the polling code group identifier from the service connection identification unit and the polling code group management unit, assigns a dedicated orthogonal code to a subscriber station corresponding to the connection identification information, and identifies the polling code group identifier and the connection identification. Orthogonal code management unit for managing the orthogonal code database in response to information The uplink scheduling apparatus further comprises a. The method of claim 16, A bandwidth allocator configured to receive an orthogonal code from the subscriber station, obtain an amount of bandwidth corresponding to the orthogonal code from the orthogonal code database, and allocate an uplink bandwidth to the terminal by the amount of the bandwidth; Uplink scheduling apparatus further comprising. An uplink scheduling apparatus in which a subscriber station performs an uplink bandwidth request for a polling service to a base station in a broadband wireless access system, A receiver configured to receive and output an identifier of a polling code group registered by the subscriber station from the base station; A band request code generator for calculating a size of a bandwidth required for transmitting uplink data and outputting a code corresponding to the bandwidth size; A bandwidth allocation scheduler for extracting and outputting band request code position information from the downlink data frame when the polling code group identifier is included in the downlink data frame received from the base station; And Bandwidth request unit for allocating the code received from the band request code generation unit to the band corresponding to the band request code position information received from the bandwidth allocation scheduler unit to transmit to the base station Uplink scheduling apparatus comprising a. The method of claim 18, Orthogonal code database in which a dedicated orthogonal code received from the base station is stored More, And the band request code generator is configured to output an orthogonal code corresponding to the bandwidth from the orthogonal code database and output the orthogonal code.

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