KR20050041207A - Method and apparatus for packet scheduling in ofdma packet mobile communication system - Google Patents

Abstract

The present invention relates to a packet scheduling method and apparatus in an OFDM scheme packet mobile communication system.

In a packet scheduling method according to an aspect of the present invention, after scheduling a terminal using uplink channel information of the terminal, packet traffic in which the uplink buffer information of the terminal is briefly displayed in the header of the uplink data according to the scheduling result. Is received through the uplink channel. The uplink is scheduled using the received buffer information and the uplink power information.

According to the present invention, there is an effect that can improve the performance of uplink scheduling.

Description

Packet scheduling method and apparatus in an OPDM packet communication system {METHOD AND APPARATUS FOR PACKET SCHEDULING IN OFDMA PACKET MOBILE COMMUNICATION SYSTEM}

The present invention relates to a packet scheduling method in an orthogonal frequency division multiplex (OFDM) -based packet mobile communication system, and more particularly, to an uplink When transmitting traffic, the uplink buffer information of the terminal is displayed in the packet header and transmitted, and the base station schedules an uplink using the uplink buffer information of the terminal to allow uplink packet transmission of the terminal. A packet scheduling method and apparatus in a system.

1 is a block diagram of a conventional OFDM packet packet communication system.

In an OFDM packet mobile communication system, one base station 20 transmits and receives data to and from a plurality of terminals 12, 14, and 16 through a wireless channel environment.

The base station 20 receives packet traffic from the wired Internet network 30 and transmits the received packet traffic to each terminal 10 using the OFDM scheme. In addition, the terminal 10 receives the packet traffic transmitted using the OFDM scheme, demodulates the uplink OFDM signal, and transmits the packet traffic to the wired Internet network 30.

The terminal 10 demodulates the downlink OFDM signal transmitted from the base station 20, and then receives only packet traffic transmitted from the base station 20, selects only the channel signal allocated to the terminal 10 thereof, thereby valid packet data. Extract

2 illustrates transmission and reception of uplink packet traffic in an OFDM packet mobile communication system.

In the OFDM packet mobile communication system, uplink uses packet scheduling, which is an uplink radio resource control operation, in a base station 20 capable of managing all terminals 10 because a plurality of terminals 10 use a common radio channel. To perform.

As shown in FIG. 2, the base station 20 manages a plurality of terminals 10 by scheduling an uplink channel of the terminal 10 belonging to its cell in the OFDM scheme mobile communication system.

The base station 20 performs packet scheduling for managing uplink and manages a radio channel using the registration information of the terminal 10 registered in the base station 20.

The packet scheduling apparatus 22 schedules a packet data transmission permission period of the plurality of terminals 10 communicating with the base station 20 by transmitting the packet data to the base station 20 and receiving the packet data from the base station 20.

The first storage unit 24 stores the terminal registration information registered in the base station 20.

The second storage unit 26 stores uplink channel power information.

Specifically, the base station 20 is the terminal # 1 (12), the terminal # 2 (14), the terminal # 3 (16) in the registered state of the registered information of the registered terminal and the upstream measured by the base station 20 The power information of the link channel is used to select a terminal to be allowed to transmit next time.

For example, the number of allowable uplink channels is two, and the signal strength of the uplink measured by the base station 20 is greater than that of the terminal # 1 (12) and the terminal # 3 (16) compared to the terminal # 2 (14). Preferably, the base station 20 selects the terminal # 1 (12) and the terminal # 3 (16) and transmits an uplink transmission permission signal to each terminal (12, 16) (S10). Upon receiving the transmission permission signal from the base station 20, the terminals 12 and 16 modulate data stored in the uplink buffer and transmit the modulated data to the base station 20 (S20). However, when the terminal 14, which has not received the transmission permission signal from the base station 20, modulates the data stored in the uplink buffer and transmits the data to the base station 20 (S30), a collision of common radio resources occurs and the base station ( In 20), the radio channel cannot be demodulated.

Accordingly, there is a problem that the base station 20 cannot use the uplink buffer information of the terminal 10.

The amount of packet traffic is variably input to the buffer of each terminal 10 according to time, and this information should be informed to the base station 20 to enable efficient resource management. When packet scheduling is performed in the absence of buffer information of the terminal 10, an inefficient problem of allocating an uplink channel to the terminal 10 having no data to be transmitted occurs, and buffer information of the terminal 10 is transmitted to the base station 20. In order to transmit the data, an overhead of using a downlink channel is generated to transmit this control command, resulting in a waste of resources.

The present invention is to solve the above problems,

An object of the present invention is to provide an OFDM packet mobile communication in which a base station capable of performing uplink resource management in an OFDM packet mobile communication system performs data transmission permission in proportion to the uplink power information of a terminal and the data amount of a terminal buffer. An object of the present invention is to provide a packet scheduling method and apparatus in a system.

In order to achieve the above object,

Packet scheduling method in an OFDM packet system according to an aspect of the present invention,

A method of performing packet scheduling for an uplink channel of a plurality of terminals in a packet scheduling apparatus managed by a base station of an Orthogonal Frequency Division Multiple Access (OFDMA) packet mobile communication system,

a) performing packet scheduling based on power information of an uplink channel of multiple terminals; b) receiving respective buffer information from the plurality of terminals based on the packet scheduling result of step a); And c) packet scheduling using power information of an uplink channel of the plurality of terminals and buffer information of each transmitted terminal.

After step c), steps b) and c) are repeatedly performed until the amount of packet data present in the buffer of the terminal is simultaneously small or the amount of packet data present in the buffer of the terminal is not present at the same time. It is done. In addition, step b) and step c) is repeatedly performed until the amount of packet data existing in the buffer of the terminal is large.

And step c),

Iii) demodulating buffer information of each transmitted terminal; Ii) storing the demodulated buffer information; Iv) selecting a terminal to allow packet traffic transmission based on the stored buffer information and power information of the uplink channel; And iii) transmitting a transmission permission signal to the selected terminal.

After step iii), the method further includes receiving packet data briefly indicating buffer information from the terminal receiving the transmission permission signal from step iv).

The buffer information of the terminal is characterized by the uplink packet data state.

The state of the packet data is based on the amount of uplink packet data present in the buffer of the terminal.

In addition, when there is a large amount of packet data present in the buffer of at least one terminal, it is characterized by selecting a terminal to allow transmission in consideration of the buffer information of the terminal prior to the power information of the uplink channel.

The buffer information may be briefly displayed in a packet header of the packet data.

Packet scheduling apparatus in an OFDM packet mobile communication system according to another aspect of the present invention,

An apparatus managed by a base station of a system providing a service by an OFDM scheme and performing packet scheduling for an uplink channel of a plurality of terminals.

A first storage unit storing registration information of each terminal including data buffer information of the terminal to recognize and manage the respective terminals; A second storage unit storing uplink power information of the plurality of terminals; And a packet scheduling unit for determining a packet data transmission permission of the terminal using buffer information stored in the first storage unit and power information of an uplink channel stored in the second storage unit.

The data buffer information may be briefly displayed and transmitted in a packet header of a packet frame transmitted from the terminal to the base station.

The data buffer information is characterized by indicating the packet data amount of the terminal.

And the terminal,

An uplink data buffer for temporarily storing a packet frame in which input packet data is converted; And a storage unit which stores information according to the state of the uplink data buffer.

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

First, in describing the present invention, if it is determined that a detailed description of a related known function or configuration may unnecessarily obscure the subject matter of the present invention, the detailed description thereof will be omitted.

3 is a diagram illustrating terminal buffer information transmission in an OFDM packet mobile communication system according to an embodiment of the present invention.

As illustrated in FIG. 3, an OFDM packet mobile communication system includes a base station 200 for wireless communication with a plurality of terminals.

The base station 200 manages a plurality of terminals 100 belonging to its own cell. The base station 200 performs the uplink management function of the plurality of terminals 100 belonging to its own cell by the packet scheduling apparatus 210.

The packet scheduling apparatus 210 includes a packet scheduling unit 212, a first storage unit 214, and a second storage unit 216.

The first storage unit 214 transmits packet data to the base station 200 and the base station 200 communicates with each other so that the base station 200 communicates with the multiple terminals 100 that receive the packet data from the base station 200. The information of each terminal 100 capable of managing and recognizing 100 is registered in the base station 200, and the registration information of each terminal 100 registered in the base station 200 is stored. In addition, the first storage unit 214 stores information according to the state of the uplink data buffer of each terminal 100 transmitted from each terminal 100.

 The second storage unit 216 stores power information of an uplink channel of each terminal 100 measured by the base station 200.

The packet scheduling unit 212 schedules a packet data transmission permission cycle of the plurality of terminals 100 communicating with the base station 200. In order to schedule the uplink channel of the terminal 100, the terminal 100 outputs uplink buffer information of each terminal 100 from the first storage unit 214, and each terminal (from the second storage unit 216). 100 outputs power information of the uplink channel. The terminal 100 managed by the base station 200 is scheduled by combining the output data buffer information and the uplink power information.

There are a plurality of terminals 100 in one base station, and communicates with the base station 200 by transmitting packet data to the base station 200 and receiving the packet data from the base station 200.

The terminal 100 includes uplink data buffers 114 and 124 and storage units 112 and 122.

The uplink data buffers 114 and 124 temporarily store packet data input to the terminal 100. Packet data input to the uplink data buffers 114 and 124 is converted into packet frames in the physical layer.

The storage units 112 and 122 store uplink buffer information according to the states of the uplink data buffers 114 and 124. The bit is briefly displayed according to the amount of packet data present in the uplink data buffers 114 and 124 and stored.

The terminal 100 transmits uplink buffer information stored in the storage units 112 and 122 to the base station 200. In this case, as the uplink buffer information, a bit corresponding to the amount of packet data existing in the uplink data buffers 114 and 124 is selected, and the selected bit is displayed in the packet header of the packet frame, and the base station 200 together with the packet data. Is sent.

When the uplink management function is performed by packet scheduling, the terminal 100 registered in the base station 200 receives a transmission permission according to terminal registration information and uplink power information registered in the base station 200.

According to an embodiment of the present invention, the terminal 100 transmits buffer information of the terminal 100 to the base station 200 through the uplink channel before packet scheduling is performed from the base station 200.

The packet scheduling apparatus 210 of the base station 200 receives the buffer information of the terminal 100 transmitted from the terminal 100 and measures the state of the entire terminal 100 using the received buffer information. Then, the specific terminal is selected based on the measured value by measuring the power information of the uplink channel, and the base station 200 transmits a transmission permission to the specific terminal selected by the packet scheduling apparatus 210.

For example, there are two terminals 100 registered in the base station 200 (referred to as terminal # 1 (110) and terminal # 2 (120), respectively) and the uplink data buffer of each terminal. It is assumed that the packet traffic of the terminal # 1 (110) is greater than the terminal # 2 (120), the power of the uplink channel of the terminal # 2 (120) is higher than the power of the uplink channel of the terminal # 1 (110).

The terminal # 1 110 includes an uplink data buffer 114 that temporarily stores received packet data and a storage 112 that stores state information of the uplink data buffer 114.

The terminal # 2 120 includes an uplink data buffer 124 that temporarily stores the received packet data and a storage 122 that stores state information of the uplink data buffer 124.

The base station 200 determines the priority of the terminal 100 to be transmitted with the power of the uplink channel of the terminal 100. Then, the priority of the terminal 100 to be transmitted is in order of the terminal # 2 120 and the terminal # 1 110. The scheduling is performed at the determined priority, and the uplink data is transmitted to the base station 200 in the order of the terminal # 2 120 and the terminal # 1 110. In this case, the terminal # 1 (110), the terminal # 2 (120) outputs the packet frame to be transmitted at the current time point from the uplink data buffers (114, 124), and then uplink data from the storage (112, 122) Packet information is transmitted by briefly displaying the state information of the buffers 114 and 124 in the packet header of the packet frame (S100).

Then, when the base station 200 performs the next scheduling, scheduling is performed considering the uplink power information and the buffer state of the terminal at the same time.

However, according to the exemplary embodiment of the present invention, if the terminal 110 or 120 is close to the base station 200 and the power of the uplink channel is good, but the data to be transmitted is low, the priority is lowered when scheduling. If the uplink power is bad and there is a lot of data to transmit, the priority is increased during scheduling to transmit the data quickly.

Therefore, according to the uplink power, the priorities of the terminals 110 and 120 are determined in the order of the terminal # 2 120 and the terminal # 1 110, but the base station 200 is the terminal # 1 110 and the terminal #. The state of each terminal is measured from the packet data transmitted from 2 (120), and the terminal # 1 (110) having a lot of packet traffic is selected according to the buffer state of each terminal (110, 120), and the transmission permission is first transmitted ( S110). Terminal # 1 (110) receiving the transmission permission (S110) modulates the packet data stored in the data buffer 114 of the uplink to transmit to the base station (S120). On the other hand, the terminal # 2 120 that has not received the transmission permission from the base station 200 cannot transmit the packet data (S130). Therefore, at the next time point, the base station 200 receives the grant signal and then transmits packet data.

When all terminals managed by the base station have more or less packet data to transmit at the same time or there is no packet data to transmit, the priority of the terminals is determined by using uplink power information.

 4 is a diagram illustrating a buffer information transmission format according to an embodiment of the present invention.

As shown in FIG. 4, when packet data is input to the uplink data buffers 114 and 124, the MAC layer converts the packet data into the MAC frame 400 and transmits the packet data. In this case, the MAC frame 400 includes a MAC header 410, a MAC payload 420, and a CRC 430.

The MAC header 410 indicates a target address, data format, etc. to receive packet traffic and has a fixed length. The uplink buffer information of the terminal 100 is briefly displayed on the MAC header 410.

The MAC payload 420 stores internet traffic and has a length that varies according to the type of packet.

The CRC 430 stores information for error detection.

Specifically, when the terminal 100 transmits uplink packet traffic, the terminal 100 buffer information of the time point is displayed on the MAC header 410 to be transmitted to the base station 200, and the base station 200 transmits this information. Packet scheduling to determine transmission permission of packet traffic. That is, the base station 200 determines the transmission permission of the next packet traffic of the terminal 100 based on the buffer information of the terminal 100 transmitted at the present time.

For example, among the terminals registered in the base station 200, a transmission permission is given to a terminal having a large amount of data in the buffer so that data is not delayed.

Table 1 shows an example of a state of a buffer according to the display of buffer information.

Display method (bitwise) The state of the buffer Remarks 00 Stay current When the state of the buffer is stable 01 Request for increase of grant period When there is heavy packet traffic in the buffer 10 Request for Reduction of Authorization Cycle When there is less packet traffic in the buffer 11 Request to Minimize Authorization Cycle When the buffer is empty

In Table 2, buffer information is displayed using 2 bits, and the terminal 100 requests transmission permission and transmission permission reduction according to the state of the buffer. Then, the packet scheduling unit 210 of the base station 200 refers to the transmission permission and the transmission permission reduction request information transmitted from the terminal 100 to select a terminal to indicate the transmission permission so that the state of the terminal buffer can be stably operated. do.

Specifically, when transmitting the packet data, the terminal 100 transmits the packet data by simplifying the buffer state of the terminal at the same time and displaying it in the packet header.

As shown in Table 2, when the state of the buffers 114 and 124 is stable, the terminal 100 displays '00' in the packet header 410 of the packet frame 400 to maintain the current state as the base station 200. When a request is made and the terminal 100 has a lot of packet traffic in the buffers 114 and 124, the terminal 100 displays a '01' in the packet header 410 of the packet frame 400 to request a request for increasing the transmission permission period to the base station 200. do. When the packet traffic is low in the buffers 114 and 124, the terminal 100 displays a '10' in the packet header 410 of the packet frame 400 to request a decrease in the transmission permission period. In addition, when the buffers 114 and 124 are empty, the terminal 100 displays a '11' in the packet header 410 of the packet frame 400 to request a minimum transmission permission period.

Here, Table 2 shows the state of the buffer according to the display of the buffer information as an embodiment, and is not limited to the number of bits and the bit display method shown in Table 2, the state of the buffer according to the bit display, and the request condition according to the state of the buffer. . For example, you can use three bits of the buffer representation to further refine the state of the buffer.

The above embodiments are intended to illustrate the present invention, the scope of the present invention is not limited to the embodiments, it can be modified or modified by those skilled in the art within the scope of the invention defined by the appended claims. .

According to the present invention, uplink radio channel transmission performance is improved by granting data transmission in proportion to the data amount of the terminal buffer in the base station performing uplink resource management in an OFDM packet packet communication system. In addition, it is possible to minimize the amount of data additionally necessary by simplifying and transmitting the terminal buffer information in the MAC header.

1 is a block diagram of a typical OFDM packet mobile communication system.

2 is a diagram illustrating transmission and reception of uplink packet traffic in an OFDM packet mobile communication system.

3 is a diagram illustrating transmission of buffer information by a terminal in an OFDM packet mobile communication system according to an embodiment of the present invention.

4 is a diagram illustrating a buffer information transmission format according to an embodiment of the present invention.

Claims (13)

In a packet scheduling apparatus managed by a base station of an Orthogonal Frequency Division Multiple Access (OFDMA) packet mobile communication system, a method of performing packet scheduling for an uplink channel of a plurality of terminals is provided. a) performing packet scheduling based on power information of an uplink channel of multiple terminals; b) receiving respective buffer information from the plurality of terminals based on the packet scheduling result of step a); And c) packet scheduling using power information of an uplink channel of the plurality of terminals and buffer information of each transmitted terminal; Packet scheduling method in an OFDM packet mobile communication system comprising a. The method of claim 1 Step c) is Iii) demodulating buffer information of each transmitted terminal; Ii) storing the demodulated buffer information; Iv) selecting a terminal to allow packet traffic transmission based on the stored buffer information and power information of the uplink channel; And Iii) transmitting a transmission permission signal to the selected terminal Packet scheduling method in an OFDM packet mobile communication system comprising a. The method of claim 2, The buffer information of the terminal according to the uplink packet data state, characterized in that the packet scheduling method in the packet mobile communication system of the OFDM method. The method of claim 3, wherein The packet scheduling method of claim 1, wherein the state of the packet data is based on the amount of uplink packet data existing in the buffer of the terminal. The method of claim 2, Step iii), If there is a large amount of packet data in the buffer of at least one terminal, the packet mobile communication of the OFDM method characterized in that to select the terminal to allow transmission in consideration of the buffer information of the terminal prior to the power information of the uplink channel Packet scheduling method in system. The method of claim 2, After step iii) Receiving packet data briefly indicating buffer information from the terminal receiving the transmission permission signal from step iii); Packet scheduling method in an OFDM packet mobile communication system further comprising. The method of claim 6, And the buffer information is briefly displayed in a packet header of the packet data. The method of claim 1, After step c) In an OFDM packet mobile communication system performing steps b) and c) repeatedly until the amount of packet data present in the buffer of the terminal is simultaneously small or the amount of packet data present in the buffer of the terminal is not present at the same time. Packet scheduling method. The method of claim 1, After step c) A packet scheduling method in an OFDM packet mobile communication system performing steps b) and c) repeatedly until there is a large amount of packet data existing in a buffer of the terminal. An apparatus for managing a base station of a system providing a service by the OFDM scheme and performing packet scheduling for an uplink channel of a plurality of terminals. A first storage unit storing registration information of each terminal including data buffer information of the terminal to recognize and manage the respective terminals; A second storage unit storing uplink power information of the plurality of terminals; And A packet scheduling unit that determines the packet data transmission permission of the terminal by using the buffer information stored in the first storage unit and the power information of the uplink channel stored in the second storage unit. Packet scheduling apparatus in an OFDM scheme packet mobile communication system comprising a. The method of claim 10, The data buffer information is a packet scheduling apparatus in the OFDM mobile packet communication system, characterized in that briefly displayed in the packet header of the packet frame transmitted from the terminal to the base station. The method of claim 11, And the data buffer information indicates an amount of packet data of the terminal. The method of claim 12, The terminal, An uplink data buffer for temporarily storing a packet frame in which input packet data is converted; And Storage unit for storing information according to the state of the uplink data buffer Packet scheduling apparatus in an OFDM packet system including a.