KR100921773B1 - Method for distributed scheduling and accessing, method for access based on priority in uplink wireless communication system and apparatus thereof - Google Patents

Abstract

The present invention relates to an uplink distributed based scheduling method, an access method and an apparatus in a wireless communication system.

The present invention can efficiently manage resources in an uplink distributed based wireless communication system, and can increase resource efficiency and guarantee quality of service (QoS) through distributed based scheduling. In addition, the UE manages its own scheduling priority to effectively reduce the uplink signaling, reduce the scheduling processing time of the base station, while efficiently guaranteeing QoS in a distributed-based system based on any approach Service yield can be increased.

Uplink, distributed base, scheduling, priority access control, resource allocation

Description

Method for distributed scheduling and accessing, method for access based on priority in uplink wireless communication system and apparatus

The present invention relates to an uplink distributed based scheduling method, an access method and an apparatus in a wireless communication system.

In a wireless communication system, when a resource is allocated to a terminal, the base station allocates the resource in a central control manner. That is, the central base station collects channel state and buffer state information of all terminals, and runs a packet scheduler to schedule the amount of resources allocated to the terminal every frame. In other words, a terminal having data to be transmitted to the base station in the buffer transmits a bandwidth request header to the base station in order to transmit data on the uplink.

At this time, the base station must keep track of the channel state of the terminal to increase channel efficiency and data reception success rate through adaptive modulation and coding (AMC) and power control. To this end, the activated terminal should periodically measure the channel state and report it to the base station, and signaling overhead increases for the terminal to measure the channel state.

In other words, the terminal that is actually scheduled and allocated resources from the base station, although the base station is limited by the amount of resources in one frame, the base station updates the priority of all the terminals requesting the band every frame, the terminal having the highest priority It allocates resources by searching for. This is a problem that the load and signaling overhead is accelerated as the number of terminals increases.

Accordingly, the present invention provides an uplink distribution-based scheduling method and apparatus for efficient scheduling and increasing the efficiency of radio resources.

The method for scheduling on a distributed basis to allocate resources to a plurality of terminals which is a feature of the present invention for achieving the technical problem of the present invention,

Transmitting a scheduling priority threshold value to a plurality of terminals; Receiving, from each terminal, a band request message selectively transmitted by the plurality of terminals based on the scheduling priority threshold value; Allowing access of a terminal in an order of increasing scheduling priority information based on scheduling priority information included in the band request message and corresponding to each terminal; And allocating a band to the terminal to which the access is allowed.

In another aspect of the present invention for achieving the technical problem of the present invention, a method for scheduling on a distributed basis to be allocated resources from a base station,

Calculating a scheduling priority value based on scheduling plan information collected through an access procedure with the base station; Comparing the scheduling priority value with the scheduling priority value broadcast from the base station when data to be transmitted to the base station is generated; And if the scheduling priority value is greater than or equal to the scheduling priority threshold, generating and transmitting a band request message to the base station.

Terminal another feature of the present invention for achieving the technical problem of the present invention,

A scheduling plan information storage unit for storing scheduling plan information received from the base station; A scheduling priority calculation unit calculating a scheduling priority based on the scheduling plan information, and updating the scheduling priority every frame according to the scheduling plan information; And a band request message for generating and transmitting a band request message to be transmitted to the base station by comparing the scheduling priority value with the scheduling priority threshold value received from the base station, and including information on the calculated or updated scheduling priority. Contains wealth.

Another aspect of the present invention for achieving the technical problem of the present invention is a base station,

A scheduling priority threshold calculator configured to calculate or update a scheduling priority threshold based on the threshold update related information; And a scheduling priority threshold storage unit for storing the threshold value calculated or updated by the scheduling priority threshold calculator and broadcasting to the terminal whenever the scheduling priority threshold value is newly stored.

Therefore, it is possible to efficiently manage resources in a wireless communication system, and it is possible to increase the efficiency of resources and guarantee the QoS of a service through distributed-based scheduling.

In addition, the terminal manages its own scheduling priority, it is possible to efficiently reduce the uplink signaling, and shorten the scheduling process time of the base station. In addition, it is possible to increase service yield while efficiently guaranteeing QoS in a distributed based system based on any approach.

DETAILED DESCRIPTION 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, and like reference numerals designate like parts throughout the specification.

Throughout the specification, when a part is said to "include" a certain component, it means that it can further include other components, without excluding other components unless specifically stated otherwise. In addition, the terms “… unit”, “… unit”, “module”, etc. described in the specification mean a unit that processes at least one function or operation, which may be implemented by hardware or software or a combination of hardware and software. have.

In this specification, a mobile station (MS) includes a terminal, a mobile terminal (MT), a subscriber station (SS), a portable subscriber station (PSS), and a user equipment. It may also refer to a user equipment (UE), an access terminal (AT), and the like, and may include all or some functions of a mobile terminal, a subscriber station, a portable subscriber station, a user device, and the like.

In the present specification, a base station (BS) is an access point (AP), a radio access station (Radio Access Station, RAS), a Node B (Node B), a base transceiver station (Base Transceiver Station, BTS), MMR ( Mobile Multihop Relay) -BS and the like, and may include all or part of functions such as an access point, a radio access station, a Node B, a base transceiver station, and an MMR-BS.

Before describing a random access control and scheduling method according to an embodiment of the present invention, a system structure diagram of a general central control scheme and a system structure diagram of a distributed control scheme will be described with reference to FIGS. 1 and 2.

1 is a system structural diagram of a general central control method.

As shown in FIG. 1, the central control scheme drives packet scheduling based on feedback information transmitted from a terminal, thereby increasing system capacity while satisfying a quality of service required by each terminal.

That is, the base station 20 receives the band request message from the plurality of terminals 10-1 to 10-3 in its area, and resources to the terminal based on the channel state and service QoS information of the terminal included in the message. Allocate At this time, the amount of resources that the base station 20 can allocate to the terminals 10-1 to 10-3 per frame is limited. Therefore, the base station 20 calculates scheduling priorities for all terminals requesting bands and allocates resources in order of higher priority terminals.

In the case of allocating resources to the terminal by the central control method as shown in FIG. 1, the system load and signaling overhead required for searching the priorities for the terminals 10-1 to 10-3 increase. On the contrary, there is a resource allocation method of a distributed control method having a right of use of a channel through a random access method. This will be described with reference to FIG. 2.

2 is a system structural diagram of a general distributed control method.

As shown in FIG. 2, the distributed control method has less overhead than the central control method in which the base station 20 determines resource allocation of all terminals 10-1 to 10-5. However, in the distributed control system, since the collision probability increases rapidly as the load of the random access channel increases, as shown in FIG. 2 (a), the access frequency may be changed by using a back off mechanism or through load control. You have to control it.

In addition, the base station 20 defines a plurality of access terminal classes (Quality of Service) for the QoS (Quality of Service) of the terminals (10-1 to 10-5), the terminals (10-1 to 10-5) Load control is performed according to the priority class of to control against collision as in (b). Such a method lowers the load of the system by prohibiting access of the terminals 10-1 to 10-5 belonging to the low priority class when the load of the system is high. However, load control based on the priority class of the terminal used in the distributed control scheme does not consider scheduling priorities of the terminals 10-1 to 10-5, and thus, QoS is difficult to guarantee.

Accordingly, embodiments of the present invention will be described with reference to FIGS. 3 and 4 for the structure of a terminal and a base station capable of guaranteeing QoS while increasing the efficiency of a band in a wireless communication system.

3 is a structural diagram of a terminal according to an embodiment of the present invention, and FIG. 4 is a structural diagram of a base station according to an embodiment of the present invention.

First, a structure of the terminal 100 will be described. As shown in FIG. 3, the terminal 100 includes a scheduling plan information storage unit 110, a scheduling priority calculator 120, a band request message generator 130, and It includes a data storage unit 140.

The scheduling plan information storage unit 110 stores scheduling plan information transmitted from the base station during the initial connection with the base station or during the service from the base station. Herein, the scheduling plan information means scheduling algorithm information driven by a packet scheduler located in a base station or a priority calculation method corresponding thereto. In this case, the scheduling algorithm is a function of considering at least one of delay information, channel quality information, buffer length information, or target service rate information of a service. At this time, each of the information is already known in the embodiments of the present invention will be omitted a detailed description.

The scheduling priority calculator 120 calculates the scheduling priority of the terminal 100 according to the frame scheduling plan information based on the scheduling plan information stored in the scheduling plan information storage 110. Alternatively, even when data to be transmitted to the base station is stored in the data storage 140, the scheduling priority is calculated and updated.

The scheduling priority calculated here may be used for backoff control when a band request is attempted along with a scheduling priority threshold received from a base station. That is, the greater the scheduling priority of the terminal 100, or the greater the difference between the scheduling priority and the scheduling priority threshold value, the higher the priority of the terminal 100, so that the back off delay may be set smaller.

On the contrary, the lower the scheduling priority of the terminal 100 or the smaller the difference between the scheduling priority and the scheduling priority threshold value, the lower the priority of the terminal, so that the back-off delay may be large. In this case, the back off means calculating a delay time before the transmission is attempted again when the data transmission signal on the transmission medium collides.

The band request message generation unit 130 stores scheduling related information (for example, band size, channel information, transmission power, etc. requested by the terminal) newly calculated or updated by the scheduling priority calculation unit 120. And a band request message to be transmitted to the base station. At this time, the band request message generation unit 130 compares its own scheduling priority value calculated by the scheduling priority calculator 120 with the scheduling priority threshold value received from the base station, and thus the scheduling priority value is the scheduling priority threshold. Generate a band request message if it is greater than or equal to the value.

The data storage unit 140 stores data to be transmitted to the base station (reference numeral 200 described in FIG. 4). In addition, while transmitting previously stored data to the base station, when new data is generated and stored, it informs the scheduling priority calculation unit 120 about this information so as to request a band for the newly generated data.

Next, the structure of the base station 200 will be described. As shown in FIG. 4, the base station includes a scheduling priority threshold calculator 210 and a scheduling priority threshold storage 220.

The scheduling priority threshold calculator 210 calculates or updates the load of the uplink system and the scheduling priority threshold accordingly based on the threshold update related information. In this case, the scheduling priority threshold may be updated periodically or may be updated when the threshold update related information is input. Here, the threshold update information includes uplink scheduling information, band request information received from the terminal 100, and uplink connection configuration information currently providing a service.

The scheduling priority threshold storage unit 220 stores the threshold value calculated or updated by the scheduling priority threshold calculation unit 210. In addition, whenever the scheduling priority threshold value is newly stored, the scheduling priority threshold value is broadcast to the terminal 100 through UCD (Uplink Channel Descript) or MAP.

Next, a method of performing scheduling in a distributed control method using the structure of a terminal and a base station described with reference to FIGS. 3 and 4 will be described with reference to FIG. 5.

5 is a flowchart of scheduling according to an embodiment of the present invention.

As shown in FIG. 5, in a wireless communication system (for example, a broadband wireless access system), the terminal 100 initially plans scheduling from the base station 200 during a process of connecting to the base station 200 or transmitting and receiving data. Obtain information (S100). The scheduling plan information includes scheduling algorithm related information generated based on channel state information, delay degree information, channel quality information, and the like, and is stored in the scheduling plan information storage unit 110. In FIG. 5, only the terminal 100 obtains scheduling plan information during an initial access process, but is not necessarily limited thereto.

Each frame, the terminal 100 calculates and updates a scheduling priority according to a known scheduling plan (S110). Here, the scheduling plan relates to a scheduling algorithm driven by the packet scheduler, and the scheduling algorithm may be expressed as a function through information such as target service delay, instantaneous channel quality, buffer length, or target service rate.

The terminal 100 determines whether data to be transmitted to the base station is generated in the buffer (or referred to as the data storage 140) (S130). If the data is generated, the band request message generator 130 compares its current scheduling priority value with the scheduling priority threshold value most recently received from the base station 200 (S140).

If its own scheduling priority value is greater than or equal to the scheduling priority threshold received from the base station, a band request is attempted to the base station (S150). However, the terminal having the scheduling priority value smaller than the scheduling priority threshold value does not attempt the band request to the base station and recalculates and updates the scheduling priority value of step S110.

In this case, the scheduling priority threshold value broadcast through the broadcast message in the base station 200 is periodically calculated and broadcast in the scheduling priority threshold calculator 210, or when the scheduling priority threshold changes, the scheduling priority threshold is changed. The value storage unit 220 is broadcast to the terminal 100 (S120). When broadcast at the base station 200, it is broadcast via UCD or MAP. Here, the base station 200 updates the uplink system load and the scheduling priority threshold accordingly based on the uplink scheduling information, the band request information received from the terminal 100, and the uplink connection configuration information currently in progress.

When the terminal 100 attempts a band request to the base station 200 through step S150, the terminal 100 transmits its channel quality information to the base station for scheduling in the base station 200. In this case, the channel quality information may be included in the band request message generated by the band request message generator 130 or piggybacked when data is transmitted. It may also be sent to the base station via another channel (eg, a control channel such as a CQI channel, etc.).

The base station receiving the band request message from the terminal 100 drives the packet scheduler (S160), and allocates an uplink band to each of the terminal 100 requesting the band. Here, the base station 200 includes feedback information (eg, buffer length of the terminal, channel state information, etc.) from terminals having a scheduling priority value greater than the scheduling priority threshold value among a plurality of terminals in its area. Receive a band request message.

In this case, FIG. 5 shows that the band is allocated to all terminals that have transmitted the band request message. However, the scheduling algorithm is updated by updating the feedback information included in the band request message or information obtained through other feedback channels, and as a result, the terminal is allocated in the order of high priority, and then the band is allocated to the terminal. It may be. If the number of terminals that are not accessible among the plurality of terminals transmitting the band request message is large, the scheduling priority threshold calculator 210 updates the scheduling priority threshold by increasing it.

In other words, when the utilization efficiency of the frame is small, that is, when the full allocation of the frame is not performed, the base station 200 sets a scheduling priority threshold to receive a rental request message from more terminals. After updating by lowering the threshold value is broadcast to the terminal. On the other hand, when the usage efficiency of the frame is consistently high and there are many terminals that have received the bandwidth request message from a plurality of terminals but have not scheduled, the scheduling priority threshold is set high and the threshold value is updated and broadcasted to the terminals (S180). ). Upon receiving the scheduling priority threshold value broadcast from the base station 200, the plurality of terminals update their scheduling priority value as soon as they receive the scheduling priority threshold value (S190).

The embodiments of the present invention described above are not implemented only through the apparatus and the method, but may be implemented through a program for realizing a function corresponding to the configuration of the embodiment of the present invention or a recording medium on which the program is recorded. Implementation may be easily implemented by those skilled in the art from the description of the above-described embodiments.

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.

1 is a system structural diagram of a general central control method.

2 is a system structural diagram of a general distributed control method.

3 is a structural diagram of a terminal according to an embodiment of the present invention.

4 is a structural diagram of a base station according to an embodiment of the present invention.

5 is a flowchart of scheduling according to an embodiment of the present invention.

Claims (15)

In the method of scheduling on a distributed basis for allocating resources to a plurality of terminals, Transmitting a scheduling priority threshold value to a plurality of terminals; Receiving, from each terminal, a band request message selectively transmitted by the plurality of terminals based on the scheduling priority threshold value; Allowing access of a terminal in an order of increasing scheduling priority information based on scheduling priority information corresponding to each terminal and allocating a band to a terminal to which the access is allowed, included in the band request message; And Updating the previously stored scheduling threshold based on the threshold update information included in the band request message. Scheduling method comprising a. The method of claim 1, Updating the scheduling threshold, Determining whether there is a change in a scheduling priority threshold stored in advance based on the threshold update related information; And Updating the scheduling priority threshold value and transmitting the updated scheduling priority threshold value to the plurality of terminals if there is a change in the scheduling priority threshold value. The scheduling method further comprising. The method of claim 2, The update related information may be any one of uplink scheduling information with the terminal, band request information included in the band request message received from the terminal, and uplink connection configuration information currently providing a service to the terminal. Way. The method of claim 2, The scheduling priority threshold value is determined using any one of uplink load and band request information, uplink connection configuration information currently connected to the terminal, and uplink frame usage efficiency information. The method of claim 1, Prior to the transmitting step, Performing an initial access procedure with the terminal; And Transmitting scheduling plan information to the terminal; The scheduling method further comprising. In accordance with claim 5, The scheduling plan information is a scheduling algorithm driven by a packet scheduler, wherein the scheduling algorithm is generated based on at least one of delay information, channel quality information, buffer length information, and target service rate information of a transmitted service. Scheduling Method. In the method for accessing the base station on a distributed basis to be allocated resources from the base station, Calculating a scheduling priority value based on scheduling plan information collected through an access procedure with the base station; When the data to be transmitted to the base station occurs, comparing the scheduling priority threshold value broadcast from the base station with the calculated scheduling priority value; And If the calculated scheduling priority value is greater than or equal to the scheduling priority threshold broadcast from the base station, generating a band request message to transmit the data to the base station and transmitting the generated bandwidth request message to the base station. Approach comprising. The method of claim 7, wherein The band request message includes the scheduling priority information and channel quality information. The method of claim 7, wherein The scheduling priority threshold value is received from the base station according to a preset period or whenever the scheduling priority threshold value is updated, and accesses to update the scheduling priority value based on the received updated scheduling priority threshold value. Way. The method according to any one of claims 7 to 9. And a back off delay using the calculated scheduling priority value and the scheduling priority threshold. A scheduling plan information storage unit for storing scheduling plan information received from the base station; A scheduling priority calculation unit calculating a scheduling priority based on the scheduling plan information, and updating the scheduling priority every frame according to the scheduling plan information; And When the data to be transmitted to the base station is generated, the scheduling priority value is compared with the scheduling priority threshold received from the base station, and if the scheduling priority value is greater than or equal to the scheduling priority threshold, the calculated or updated Band request message generation unit for generating and transmitting a band request message to be transmitted to the base station including information on the scheduling priority Terminal comprising a. The method of claim 11, The scheduling plan information, A scheduling algorithm driven by the packet scheduler, wherein the scheduling algorithm is generated based on at least one of service delay information, channel quality information, buffer length information, and target service rate information. The method of claim 11, A data storage unit for storing data to be transmitted to the base station, and notifying the scheduling priority calculator to request a band for newly stored data when new data is stored. Terminal further comprising. A scheduling priority threshold calculator configured to calculate or update a scheduling priority threshold based on the threshold update related information; And The threshold value calculated or updated by the scheduling priority threshold calculator is stored and broadcasted to the terminal whenever the scheduling priority threshold value is newly stored based on the threshold update related information included in the band request message received from the terminal. Scheduling priority threshold storage unit Base station comprising a. The method of claim 14, The threshold update information may be one of uplink scheduling information, band request information received from the terminal, and uplink connection configuration information currently providing a service.

Images