KR100600821B1 - Apparatus and method for access control in wireless packet switched cellular Orthogonal Frequency Division Multiple Access system - Google Patents

Abstract

1. TECHNICAL FIELD OF THE INVENTION

The present invention relates to a connection control apparatus and method thereof for an orthogonal frequency division multiple access system.

2. The technical problem to be solved by the invention

The present invention configures a preamble using a random access code and transmits the preamble to the base station through the preamble channel, and attempts to reconnect or completes the access according to the preamble response information received from the base station through the preamble response channel. An object of the present invention is to provide an access control apparatus and a method of an orthogonal frequency division multiple access system.

3. Summary of Solution to Invention

The present invention provides a connection control apparatus for an orthogonal frequency division multiple access system, comprising: resource selecting means for selecting transmission resource information (preamble transmission channel and code) necessary for generating a preamble; Preamble transmitting means for generating a preamble using the transmission resource information selected by the resource selecting means and transmitting the preamble to the base station; Check the preamble response information received from the base station to control the data transmission means to transmit data in accordance with the access control information corresponding to the case of the access authorization (ACK) information, and the corresponding access in the case of NACK information Preamble response processing means for retransmitting the preamble according to the control information; And said data transmitting means for transmitting data using transmission information from said base station under control of said preamble response processing means.

4. Important uses of the invention

The present invention is used for orthogonal frequency division multiple access systems.

OFDMA, access control, preamble, preamble response information, access grant (ACK) / no access (NACK) information, access control information

Description

Apparatus and method for access control in wireless packet switched cellular Orthogonal Frequency Division Multiple Access system             

1 is a configuration diagram of an access control device of an orthogonal frequency division multiple access system according to an embodiment of the present invention;

2 and 3 is a flow chart of an embodiment of a connection control method in a conventional orthogonal frequency half multiple access system;

4 is a diagram illustrating an embodiment of access control information of preamble response information according to the present invention;

5 to 7 are flowcharts illustrating an embodiment of a connection control method in an orthogonal frequency division multiple access system according to the present invention.

* Explanation of symbols for the main parts of the drawings

10: terminal 11: resource selection unit

12: preamble transmitter 13: preamble response processor

14: data transmission unit 20: base station

21: preamble receiving unit 22: resource allocation parameter management unit

23: scheduler 24: preamble response generator

25: data receiving unit

The present invention relates to an access control apparatus and a method of an orthogonal frequency division multiple access system, and more particularly, to configure a preamble using a random access code, and then transmit to a base station through a preamble channel. An apparatus and method for controlling access to an orthogonal frequency division multiple access system for attempting reconnection or completing a connection according to preamble response information received through a preamble response channel from a terminal, and accessing the preamble from a terminal through a preamble channel An apparatus and method for access control of an orthogonal frequency division multiple access system for generating preamble response information including grant (ACK) / NACK information and access control information and transmitting the preamble response information to the terminal through a preamble response channel will be.

Wireless communication system uses time division multiple access (TDMA), orthogonal frequency division multiple access (OFDMA), code division multiple access (CDMA), etc. After dividing, schedule according to each user's requirements, so that each user can share the entire resource.

In general, a random access method is a method in which a plurality of terminals transmit intermittent feature data through an uplink common channel for efficient use of resources, and all terminals randomly transmit with transmission authority. .

Meanwhile, a connection control method in a conventional orthogonal frequency division multiple access system is as follows.

First, the base station periodically transmits the access probability value to the terminal through the downlink broadcast channel. At this time, the base station limits the access attempts by reducing the access probability value when the preamble reception success rate is low because the terminal has many access attempts in the previous period, and conversely, when the preamble reception success rate is high because the access attempts are small in the previous period, the access probability value is low. Increase the terminal's connection attempt.

)을 확인하고, 임의 선택한 확률값(

)이 전송 결정 조건(

≤

)을 만족하면 임계치를 초과함에 따라 랜덤 엑세스 코드로 생성한 프리앰블을 상향링크 채널을 통해 기지국으로 전송하고, 기지국으로부터 하향링크 응답채널을 통해 그에 따른 응답을 전송받은 후에 데이터를 전송하거나 프리앰블을 재전송한다. 이 때, 단말은 기지국으로부터 접속 허용 응답을 전송받을 때까지 기 정해진 회수만큼 계속적으로 전송 전력을 높여서 프리앰블을 재전송한다. Thereafter, the terminal receives the access probability value received from the base station through the downlink broadcast channel (

), And randomly selected probability values (

) Determines the delivery decision condition (

≤

), When the threshold is exceeded, the preamble generated by the random access code is transmitted to the base station through the uplink channel, and after receiving the corresponding response through the downlink response channel from the base station, the data is transmitted or retransmitted. . At this time, the terminal retransmits the preamble by continuously increasing the transmission power by a predetermined number of times until receiving the access permission response from the base station.

Subsequently, if the preamble response information is not received from the base station even though the preamble is transmitted a predetermined number of times, the backoff process is performed. Here, the backoff process refers to a process of waiting for a predetermined time.

2 and 3, the terminal periodically receives access control information (access probability value) broadcast from the base station in order to access the base station (201 and 301).

As a randomly selected probability value from the received access probability value exceeds a preamble transmission condition, a preamble is generated with a randomly selected code (random access code) among a plurality of different codes and transmitted to a base station (202, 302). . At this time, the terminal periodically transmits the preamble until receiving the preamble response from the base station. At this time, if the preamble response is not received even though the preamble has been transmitted a predetermined number of times, after performing the backoff process, the preamble is retransmitted.

Thereafter, the base station transmits preamble response information to the terminal in response to receiving the preamble from the terminal (203, 303). At this time, the preamble response information refers to access permission (ACK) information or access not allowed (NACK) information.

Thereafter, the terminal checks the preamble response information from the base station and transmits data when the access permission information is received (204), and if the access permission information is received, the terminal performs a backoff process and then retransmits the preamble to the base station ( 304).

In the conventional orthogonal frequency division multiple access system, the access control method requires a base station to periodically transmit access control information (access probability value) to the terminal through a broadcast channel, thus wasting channel resources and transmission power and efficiency of a communication system. There was a problem that caused the degradation.

In the conventional orthogonal frequency division multiple access system, the access control method includes a preamble response information including only simple information (access grant information or access grant information) from the base station. (Timing adjustment information) and parameters for data transmission and transmission power are not known, so there is a problem in that the base station cannot be efficiently connected.

The present invention has been proposed to solve the above-mentioned problem, and a preamble is configured using a random access code and then transmitted to a base station through a preamble channel, and preamble response information received through the preamble response channel from the base station. It is an object of the present invention to provide a connection control apparatus and method of an orthogonal frequency division multiple access system for attempting reconnection or completing a connection according to the present invention.

In addition, according to the present invention, upon receiving the preamble from the terminal through the preamble channel, the preamble response information including the access grant (ACK) / no access (NACK) information and the access control information is generated to the terminal through the preamble response channel. Another object of the present invention is to provide an access control apparatus and method for an orthogonal frequency division multiple access system for transmission.

Other objects and advantages of the present invention can be understood by the following description, and will be more clearly understood by the embodiments of the present invention. Also, it will be readily appreciated that the objects and advantages of the present invention may be realized by the means and combinations thereof indicated in the claims.

An apparatus of the present invention for achieving the above object is a connection control apparatus of an orthogonal frequency division multiple access system, comprising: resource selecting means for selecting transmission resource information (preamble transmission channel and code) required for preamble generation; Preamble transmitting means for generating a preamble using the transmission resource information selected by the resource selecting means and transmitting the preamble to the base station; Check the preamble response information received from the base station to control the data transmission means to transmit data in accordance with the access control information corresponding to the case of the access authorization (ACK) information, and the corresponding access in the case of NACK information Preamble response processing means for retransmitting the preamble according to the control information; And the data transmitting means for transmitting data using the transmission information from the base station under the control of the preamble response processing means.

In addition, the method of the present invention is a connection control method in an orthogonal frequency division multiple access system, comprising: a preamble configuration step of a terminal configuring a preamble using a random access code; A preamble transmission step of transmitting the preamble configured by the terminal to a base station; A preamble response information checking step of the terminal receiving and confirming preamble response information from the base station; And an access control step in which the terminal attempts reconnection or completes access according to the preamble response information check result.

On the other hand, the apparatus of the present invention for achieving the above object, the connection control apparatus of an orthogonal frequency division multiple access system, comprising: preamble receiving means for receiving the preamble from the terminal to extract information; Resource allocation parameter management means for allocating and managing parameters to the terminal; Scheduling means for determining a data transmission time and a data transmission amount of the terminal to which a resource allocation parameter is allocated according to a transport channel condition and required quality of service (QoS) information; By using the preamble information extracted by the preamble receiving means and the parameters allocated by the resource allocation parameter management means to generate preamble response information including access permission (ACK) / non-access (NACK) and access control information for the preamble by generating Preamble response generating means for transmitting to the terminal; And data receiving means for receiving data from the terminal.

In addition, the method of the present invention, in a connection control method in an orthogonal frequency division multiple access system, includes access grant (ACK) / no access (NACK) information and access control information as a base station receives a preamble from a terminal. Generating preamble response information to generate preamble response information; And transmitting the preamble response information generated by the base station to the terminal.

The above objects, features and advantages will become more apparent from the following detailed description taken in conjunction with the accompanying drawings, whereby those skilled in the art may easily implement the technical idea of the present invention. There will be. In addition, in describing the present invention, when it is determined that the detailed description of the known technology related to the present invention may unnecessarily obscure the gist of the present invention, the detailed description thereof will be omitted. Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is a configuration diagram of an access control device of an orthogonal frequency division multiple access system according to an embodiment of the present invention.

As shown in FIG. 1, the access control apparatus of the orthogonal frequency division multiple access system according to the present invention configures a preamble using a random access code and transmits the preamble to the base station 20 through the preamble channel. In accordance with the preamble response information received through the preamble response channel from the base station 20, the terminal 10 retransmits the preamble or transmits data and receives the preamble from the terminal 10 through the preamble channel. And a base station 20 for generating preamble response information including grant (ACK) / NACK information and access control information and transmitting the preamble response information to the terminal 10 through a preamble response channel.

Here, the preamble response information will be described in more detail.

The preamble response includes access grant (ACK) / access grant (NACK) information and access control information. At this time, the access control information is changed according to the access authorization (ACK) / access authorization (NACK) information included in the preamble response information. When the access authorization information is included, the access control information is a parameter for data transmission, that is, The base station 20 includes parameters for recognizing the terminal 10 attempting access through the preamble as a target that can use data transmission channel resources, power adjustment information and timing adjustment information necessary for data transmission.

On the other hand, if the NAM information is included in the preamble response information, the access control information may include a reason for connection rejection (for example, insufficient transmission resources or detection of preamble power on a physical channel), preamble retransmission timing information ( Timing adjustment information) and power adjustment information necessary for retransmission of the preamble.

Meanwhile, the terminal 10 uses the resource selecting unit 11 for randomly selecting the transmission resource information (preamble transmission channel and code) necessary for generating the preamble and the transmission resource information selected by the resource selecting unit 11. The preamble transmitter 12 for generating the preamble and transmitting the preamble to the base station 20 and the preamble response information received from the base station 20 and checks the data according to the access control information corresponding to the ACK information. The preamble response processor 13 and the preamble response processor 13 for controlling the data transmitter 14 to transmit and retransmitting the preamble according to the access control information corresponding to the NACK information. And a data transmitter 14 for transmitting data. At this time, the data transmitter 14 receives the data transmission time and the data transmission amount from the scheduler 23 of the base station 20 and transmits the data accordingly.

Here, the preamble response processor 13 checks the preamble response information received from the base station 20, and checks the access control information corresponding to the ACK information, that is, the parameter for data transmission. The power is adjusted using the power adjustment information necessary for data transmission, and the data transmission timing is adjusted using the timing adjustment information.

In addition, the preamble response processing unit 13 checks the preamble response information received from the base station 20, and when the connection is NACK information, the corresponding access control information, that is, the reason for the connection rejection (for example, a marginal transmission) The cause of resource shortage or impossibility of detecting preamble power on a physical channel), the preamble retransmission timing is adjusted using the preamble retransmission timing information (timing control information), and the preamble transmission power is adjusted using the power control information. The result is transmitted to the resource selection unit 11.

On the other hand, the base station 20 receives the preamble from the terminal 10, the preamble receiving unit 21 for extracting information, the resource allocation parameter management unit for allocating / managing parameters to the terminal 10 that is the target of resource allocation (22), a scheduler 23 for determining the data transmission time and the amount of data transmission of the terminal 10 has been allocated the resource allocation parameter according to the transport channel conditions and the required Quality of Service (QoS) information, the preamble receiving unit 21 The preamble response information including the access grant (ACK) / disallowed access (NACK) and the access control information for the preamble is generated using the preamble information extracted from the preamble information extracted from the resource allocation parameter manager 22 and the terminal ( 10 includes a preamble response generator 24 for transmitting data and a data receiver 25 for receiving data from the data transmitter 14 of the terminal 10. .

FIG. 4 is a diagram for explaining preamble response information according to an embodiment of the present invention, and shows preamble response information including resource allocation parameters of access control information with 8 bits.

As shown in FIG. 4, bits of an 8-bit resource allocation parameter according to 1 bit of ACK / NACK information are used as resource allocation parameters in case of ACK. In case of NACK, it is used as a reason for rejection of connection and corresponding control information bit of the terminal.

In addition, the resource allocation parameter of the access control information includes power adjustment information and timing adjustment information that are used differently according to an access grant (ACK) or an access grant (NACK).

FIG. 5 is a flowchart illustrating an access control method in an orthogonal frequency division multiple access system according to an embodiment of the present invention, in which a preamble response information includes NACK information due to a problem on a physical channel. Indicates.

First, the terminal 10 configures the preamble using a random access code and transmits the preamble to the base station through the preamble channel (501). At this time, the terminal 10 periodically transmits the preamble until the base station 20 receives the preamble response.

Subsequently, after receiving the preamble response information from the base station 20, after adjusting the transmission power so that a problem does not occur in the physical channel, the preamble is retransmitted at that time using preamble retransmission timing information (timing adjustment information). (502, 503).

FIG. 6 is a flowchart illustrating an access control method in an orthogonal frequency division multiple access system according to an embodiment of the present invention, wherein the access control method when NACK information is included in preamble response information due to a lack of free transmission resources. Indicates.

First, the terminal 10 configures a preamble using a random access code and transmits the preamble to the base station through the preamble channel (601). At this time, the terminal 10 periodically transmits the preamble until the base station 20 receives the preamble response.

Subsequently, after performing the backoff process according to receiving the preamble response information from the base station 20, retransmitting the preamble after adjusting the transmission timing at the preamble transmission time point using the preamble transmission time information. (602, 603).

At this time, after performing the backoff process, the transmission resource information (power and timing information) used before the backoff is used as it is when the preamble is retransmitted. That is, a preamble is generated using transmission resource information (power adjustment information and timing adjustment information) included in the previous preamble response information.

FIG. 7 is a flowchart illustrating an access control method in an orthogonal frequency division multiple access system according to an embodiment of the present invention, and illustrates an access control method when access authorization (ACK) information is included in preamble response information.

First, the terminal 10 configures the preamble using a random access code and transmits the preamble to the base station through the preamble channel (701). At this time, the terminal 10 transmits the preamble periodically until the base station 20 receives the preamble response.

Subsequently, in response to receiving the preamble response information from the base station 20, the access permission (ACK) information and the access control information of the preamble response information are checked (702).

Thereafter, power is adjusted using power adjustment information necessary for data transmission included in the access control information, data transmission timing is adjusted using timing adjustment information, and a base station 20 is applied by applying parameters for data transmission. The data is transmitted (703, 704).

The present invention described above is capable of various substitutions, modifications, and changes without departing from the technical spirit of the present invention for those skilled in the art to which the present invention pertains. It is not limited by the drawings.

As described above, the present invention configures a preamble using a random access code and transmits the preamble to the base station through the preamble channel, and retransmits the preamble according to the preamble response information received from the base station through the preamble response channel. By transmitting data, there is an effect that the terminal can be connected to the base station more efficiently.

In addition, the present invention, according to the preamble received from the terminal through the preamble channel to generate preamble response information including access authorization (ACK) / non-access (NACK) information and access control information to the terminal through the preamble response channel In this case, the terminal can more efficiently access the base station.

In addition, the present invention has an effect that the base station adds the access control information to the preamble response information and transmits it to the terminal so that it is not necessary to periodically transmit the access control information, thereby preventing the waste of power.

In addition, according to the present invention, when the base station adds the access control information to the preamble response information, the previous preamble transmission resource information can be used as it is when the connection is refused due to a transmission resource problem that is not the cause of the physical channel. By reducing the number of times it is possible to reduce the power consumption.

Claims (9)

In the connection control device of an orthogonal frequency division multiple access system, Resource selecting means for selecting transmission resource information (preamble transmission channel and code) necessary for generating the preamble; Preamble transmitting means for generating a preamble using the transmission resource information selected by the resource selecting means and transmitting the preamble to the base station; Check the preamble response information received from the base station to control the data transmission means to transmit data in accordance with the access control information corresponding to the case of the access authorization (ACK) information, and the corresponding access in the case of NACK information Preamble response processing means for retransmitting the preamble according to the control information; And The data transmission means for transmitting data using the transmission information from the base station under the control of the preamble response processing means Connection control apparatus of the orthogonal frequency division multiple access system comprising a. The method of claim 1, The preamble response processing means, Orthogonal frequency division multiplexing, characterized in that the preamble transmitting means is controlled to transmit the preamble generated using the transmission resource information (power adjustment information and timing adjustment information) included in the previous preamble response information to the base station when the preamble is retransmitted. Connection control device of connection system. In the connection control device of an orthogonal frequency division multiple access system, Preamble receiving means for extracting information by receiving a preamble from a terminal; Resource allocation parameter management means for allocating and managing parameters to the terminal; Scheduling means for determining a data transmission time and a data transmission amount of the terminal to which a resource allocation parameter is allocated according to a transport channel condition and required quality of service (QoS) information; By using the preamble information extracted by the preamble receiving means and the parameters allocated by the resource allocation parameter management means to generate preamble response information including access permission (ACK) / non-access (NACK) and access control information for the preamble by generating Preamble response generating means for transmitting to the terminal; And Data receiving means for receiving data from the terminal Connection control apparatus of the orthogonal frequency division multiple access system comprising a. The method according to any one of claims 1 to 3, The preamble response information, Including access authorization (ACK) / access authorization (NACK) information and access control information, If the preamble response information includes access permission (ACK) information, The access control information is a parameter for data transmission, that is, a parameter for recognizing the terminal that the base station attempts to access through the preamble as a target that can use data transmission channel resources, and power control information and timing adjustment necessary for data transmission. Contains information, If the preamble response information includes NACK information, And the access control information includes information on access rejection, preamble retransmission timing information (timing adjustment information), and power adjustment information necessary for preamble retransmission. A connection control method in an orthogonal frequency division multiple access system, A preamble configuration step of configuring, by the UE, a preamble using a random access code; A preamble transmission step of transmitting the preamble configured by the terminal to a base station; A preamble response information checking step of the terminal receiving and confirming preamble response information from the base station; And An access control step in which the UE attempts reconnection or completes access according to a result of confirming preamble response information Connection control method in an orthogonal frequency division multiple access system comprising a. The method of claim 5, wherein The access control step, Access control information checking step of confirming access control information corresponding to the preamble response information received from the base station including NACK information; As a result of checking the access control information, if the cause of connection failure is a problem on the physical channel, the first preamble retransmission is performed by adjusting the transmission power and then retransmitting (reconnecting) the preamble using the preamble retransmission timing information (timing adjustment information). step; A second step of retransmitting (reconnecting) the preamble at the corresponding time point using the preamble transmission time point information after performing the backoff process when the cause of the connection control information is insufficient in the free transmission resource as a result of checking the access control information; Preamble retransmission step; And As the preamble response information received from the base station includes access permission (ACK) information, power is adjusted using power adjustment information necessary for data transmission, data transmission timing is adjusted using timing adjustment information, and data transmission is performed. Connection completion step by applying parameters for Connection control method in an orthogonal frequency division multiple access system comprising a. The method of claim 6, The second preamble retransmission step, And retransmitting the preamble uses transmission resource information (power adjustment information and timing adjustment information) included in previous preamble response information. A connection control method in an orthogonal frequency division multiple access system, A preamble response information generation step of generating preamble response information including access grant (ACK) / disallowed access (NACK) information and access control information when the base station receives the preamble from the terminal; And Preamble response information transmitting step of transmitting the preamble response information generated by the base station to the terminal Connection control method in an orthogonal frequency division multiple access system comprising a. The method according to any one of claims 5 to 8, The preamble response information, Including access authorization (ACK) / access authorization (NACK) information and access control information, If the preamble response information includes access permission (ACK) information, The access control information is a parameter for data transmission, that is, a parameter for recognizing the terminal that the base station attempts to access through the preamble as a target that can use data transmission channel resources, and power control information and timing adjustment necessary for data transmission. Contains information, If the preamble response information includes NACK information, The access control information may include information on access rejection, preamble retransmission timing information (timing adjustment information), and power adjustment information required for preamble retransmission.

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