KR20100081048A - Apparatus and method for adaptive automatic repeat request scheme in a broadband wireless communication system - Google Patents

Abstract

PURPOSE: A device and a method thereof are provided to prevent resource abuse by deactivating a HARQ method in a strong electric field and to improve the reliability of data transmission by activating a HARQ method in a weak electric field. CONSTITUTION: An analyzer(408) confirms an activation request for the HARQ technique from a terminal or a deactivate request. A controller(416) activates or deactivates a HARQ method for a service flow according to the activation request of the HARQ method.

Description

Apparatus and method for adaptive retransmission scheme in broadband wireless communication system {APPARATUS AND METHOD FOR ADAPTIVE AUTOMATIC REPEAT REQUEST SCHEME IN A BROADBAND WIRELESS COMMUNICATION SYSTEM}

The present invention relates to a broadband wireless communication system, and more particularly, to an apparatus and method for performing an adaptive retransmission scheme in a broadband wireless communication system.

In order to provide a service to a user in a broadband wireless communication system, a base station and a terminal may be configured according to a quality of service (QoS) parameter for generating a service flow, a QoS provided by a terminal, and a QoS provided by a base station. After discussing items such as priority, traffic rate, jitter, error correction, and the like, a session or connection is opened. In general, some of the items listed above may be changed during service provision, while others remain initially set.

  Among the items that are determined during initial connection and do not change during service, there is a hybrid-automatic repeat reQuest (HARQ) technique used to cope with error conditions that may occur in a wireless environment. Since the HARQ technique involves retransmission due to operating characteristics, it increases jitter between packets. However, in the case of Voice over Internet Protocol (VoIP) services, jitter between packets causes the vocoder to degrade voice resiliency, resulting in degradation of voice quality. Accordingly, VoIP has been used without H-ARQ in a wireless environment to prevent degradation of voice quality. As a result, in the strong electric field environment, no big problem occurs, but in the weak electric field environment, the voice quality is seriously degraded due to packet loss due to the radio wave environment.

As described above, in the case of a service that does not apply the HARQ scheme, such as the VoIP service, there is no countermeasure for preventing a deterioration in service quality due to an error condition in a weak electric field environment. Therefore, an alternative for preventing a deterioration of service quality due to an error situation for a service which is not configured to apply the HARQ scheme should be presented.

Accordingly, an object of the present invention is to provide an apparatus and method for preventing a deterioration in service quality according to an error condition for a service which is not configured to apply a hybrid automatic repeat request (HARQ) technique in a broadband wireless communication system.

Another object of the present invention is to provide an apparatus and method for adaptively applying a HARQ scheme according to a communication environment in a broadband wireless communication system.

It is still another object of the present invention to provide an apparatus and method for activating and deactivating HARQ scheme according to electric field strength in a broadband wireless communication system.

According to the first aspect of the present invention for achieving the above object, the operation method of the terminal in a broadband wireless communication system, the process of calculating the electric field strength indicator indicating the electric field strength when the service flow is generated, and the electric field strength indicator is a threshold value If smaller, requesting activation of a hybrid automatic repeat request (HARQ) scheme for the service flow; requesting deactivation of the HARQ scheme for the service flow if the field strength indicator is greater than or equal to the threshold. Characterized in that it comprises a.

According to a second aspect of the present invention for achieving the above object, an operation method of a base station in a broadband wireless communication system, the process of confirming the activation request or deactivation request for the HARQ method from the terminal, when generating a service flow, When the activation of the HARQ scheme is requested, a process of activating the HARQ scheme for the service flow, and if the deactivation of the HARQ scheme is requested, characterized in that it comprises a step of deactivating the HARQ scheme for the service flow.

According to a third aspect of the present invention for achieving the above object, in a broadband wireless communication system, a terminal device includes a measuring device that calculates an electric field strength indicator indicating an electric field strength when a service flow is generated, and the electric field strength indicator is smaller than a threshold value. If so, it is characterized in that it comprises a controller for requesting activation of the HARQ scheme for the service flow, and requesting deactivation of the HARQ scheme for the service flow if the electric field strength indicator is greater than or equal to the threshold.

According to a fourth aspect of the present invention for achieving the above object, a base station apparatus in a broadband wireless communication system, when generating a service flow, an interpreter for checking the activation request or deactivation request for the HARQ scheme from the terminal, the HARQ scheme The controller may include: a controller for activating a HARQ scheme for the service flow when the activation of the request is requested, and deactivating the HARQ scheme for the service flow when the deactivation of the HARQ scheme is requested.

In a broadband wireless communication system, it is possible to prevent resource waste by disabling the HARQ technique in a strong electric field when providing data services, and improve reliability of data transmission by enabling the HARQ technique in a weak electric field.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the following description of the present invention, when 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.

Hereinafter, a description will be given of a technique for adaptively applying a HARQ scheme according to a communication environment in a broadband wireless communication system. Hereinafter, the present invention will be described using an Orthogonal Frequency Division Multiplexing (OFDM) / Orthogonal Frequency Division Multiple Access (OFDMA) scheme as an example. The same applies to other wireless communication systems.

The present invention proposes the same method for maintaining the quality of service in the weak field environment.

First, a method of enabling / disabling a HARQ (Hybird Automatic Repeat reQuest) at the start of a connection or during operation. The UE requests the base station to include HARQ activation / deactivation in the connection setting information according to the strength of the received signal immediately before the connection is set up. That is, when a parameter indicating a channel state such as a received signal strength indicator (RSSI) or a carrier to interference and noise ratio (CINR) is greater than or equal to a predetermined threshold value, the base station determines Deactivate HARQ, and vice versa, the base station activates HARQ. In addition, after the service flow is set, if it is determined that the weak electric field by the parameter indicating the channel state, such as RSSI or CINR is less than the predetermined threshold, the terminal requests the base station to activate the HARQ. After the HARQ is activated, when moving to a strong electric field region, if it is determined that the strong electric field environment is a parameter indicating a channel state such as RSSI or CINR is greater than or equal to a predetermined threshold, for a predetermined grace period. If a parameter indicating a channel state such as RSSI or CINR is continuously greater than or equal to a predetermined threshold value, and the determination is maintained as a strong electric field environment, the terminal requests the base station to deactivate the HARQ.

Second, the HARQ re-transmission count is optimized according to the quality of service (QoS) of the service. Accordingly, the number of retransmissions of HARQ is broadcast in the cell through a broadcast message such as an uplink channel descriptor (UCD), and all terminals in the cell require HARQ retransmissions as many times as the number of retransmissions. In HARQ retransmission, a delay of several frames per retransmission occurs. In general, however, 90% of the errors are overcome by the first retransmission. Therefore, when packet jitter is one of important quality of service, it is preferable to set the number of retransmissions so that a delay according to the number of retransmissions is smaller than the maximum allowable jitter when establishing a connection.

In case of handover of the terminal, the serving base station transmits HARQ activation of the terminal and the number of HARQ retransmissions of each service flow to the target base station. Accordingly, the target base station applies the HARQ activation and the number of HARQ retransmissions received from the serving base station to the service flow of the terminal.

An example of signal exchange according to communication between a terminal and a base station according to the above-described schemes is shown in FIG. 1.

Referring to FIG. 1, the terminal and the base station establish a service flow (step 101). At this time, the terminal and the base station checks the HARQ retransmission number parameter corresponding to the service flow. That is, the number of HARQ retransmissions corresponding to the characteristics of the service flow is defined in advance, and the base station and the terminal determine the number of HARQ retransmissions of the service flow according to the corresponding relationship between the prestored service flow and the number of HARQ retransmissions. In addition, the base station determines whether to activate the HARQ according to the channel state of the terminal. Here, it is assumed that the activation of the HARQ is determined.

After setting the service flow, the terminal and the base station transmit and receive data and ACK (ACKnowledge) / NACK (Non-ACK) and performs communication (step 103). That is, the terminal receives a data packet from the base station, and transmits an ACK / NACK for the data packet. At this time, if the NACK is transmitted, the base station retransmits the data packet. However, the terminal transmits NACKs for one data packet as many times as the number of HARQ retransmissions determined at the time of setting the service flow.

During the communication, the terminal recognizes that the strong electric field environment continuously for a predetermined time interval (step 105). The terminal continuously monitors the electric field strength during communication. Herein, whether the electric field is a strong electric field is determined through parameters indicating a channel state such as RSSI or CINR, and in the present invention, an index for determining the electric field strength is referred to as an electric field strength index. That is, when the electric field strength indicator is greater than or equal to a threshold, the terminal checks whether the electric field strength indicator is greater than or equal to a threshold for a predetermined time interval.

Recognizing that the strong electric field environment continues for the predetermined time period, the terminal requests HARQ deactivation from the base station (step 107). In this case, the HARQ deactivation request is performed through message transmission or through physical signal sequence transmission. Accordingly, the base station deactivates HARQ of the service flow and transmits a HARQ deactivation response to the terminal (step 109). Thereafter, the terminal and the base station transmit and receive data packets and perform communication without transmitting and receiving ACK / NACK (step 111).

During the communication, the terminal recognizes that the weak electric field environment (step 113). In this case, unlike HARQ deactivation according to the strong electric field environment, the condition that the continuous electric field strength must be maintained for a predetermined time period is not applied. Accordingly, the terminal recognizing that the weak electric field environment requests HARQ activation to the base station (step 115). Herein, the HARQ activation request is performed through message transmission or through physical signal sequence transmission. Accordingly, the base station activates HARQ of the service flow and transmits an HARQ activation response to the terminal (step 117). Thereafter, the terminal and the base station transmit and receive data packets and ACK / NACK and perform communication (step 119).

Hereinafter, the present invention will be described in detail with reference to the drawings with respect to the operation and configuration of the terminal and the base station using the HARQ scheme as described above.

2 is a flowchart illustrating an operation procedure of a terminal in a broadband wireless communication system according to an exemplary embodiment of the present invention.

Referring to FIG. 2, the terminal determines whether a service flow is generated in step 201. In other words, the terminal checks whether a new service flow is started to perform communication.

When the service flow is generated, the terminal proceeds to step 203 to check whether the electric field strength indicator is smaller than the threshold. That is, the terminal calculates the electric field strength index and compares the electric field strength index and the threshold value. Here, the electric field strength indicator is a parameter for determining whether the current weak electric field or the strong electric field is calculated based on RSSI or CINR. If the electric field strength indicator is less than the threshold, the terminal proceeds to step 205. If the electric field strength indicator is greater than or equal to the threshold, the terminal proceeds to step 213.

If the electric field strength indicator is smaller than the threshold, the terminal proceeds to step 205 and requests the base station to activate the HARQ scheme. That is, since the electric field strength is smaller than the threshold, the terminal determines that the weak electric field state and requests HARQ activation for the service flow. Herein, the HARQ activation request is performed through message transmission or through physical signal sequence transmission.

In step 207, the terminal determines whether a HARQ activation response is received from the base station. In other words, the terminal checks whether a message or a signal indicating that activation of the HARQ scheme for the service flow is completed is received from the base station.

If the HARQ activation response is received, the terminal proceeds to step 209 to perform communication with the HARQ scheme activated. Accordingly, the terminal performs an error check on the received data packet and feeds back an ACK / NACK according to the error check result.

Subsequently, the terminal proceeds to step 211 and checks whether the state of the electric field strength indicator is greater than or equal to a threshold value continuously for a predetermined time interval. That is, the terminal continuously monitors the electric field strength indicator and checks whether the electric field strength indicator is continuously greater than or equal to the threshold value during the grace period. In other words, the terminal checks whether the strong electric field environment is maintained for the predetermined time interval.

If the state in which the electric field strength indicator is greater than or equal to the threshold for the predetermined time interval is maintained, the terminal proceeds to step 213 and requests the base station to deactivate the HARQ scheme. That is, since the electric field strength is greater than or equal to the threshold, the terminal determines that the electric field is strong and requests HARQ deactivation for the service flow. Here, the HARQ deactivation request is performed through message transmission or through physical signal sequence transmission.

In step 215, the terminal determines whether a HARQ deactivation response is received from the base station. In other words, the terminal checks whether a message or a signal indicating that the deactivation of the HARQ scheme for the service flow is received from the base station is received.

If the HARQ deactivation response is received, the terminal proceeds to step 217 to perform communication with the HARQ scheme deactivated. Accordingly, the terminal performs communication without ACK / NACK feedback on the received data packet.

Subsequently, the terminal proceeds to step 219 to check whether the electric field strength indicator decreases below the threshold. That is, the terminal continuously monitors the electric field strength indicator and checks whether the electric field strength indicator is smaller than the threshold. In other words, the terminal checks whether the transition to the weak electric field environment. If the electric field strength indicator decreases below the threshold, the terminal returns to step 205.

3 is a flowchart illustrating an operation procedure of a base station in a broadband wireless communication system according to an exemplary embodiment of the present invention.

Referring to FIG. 3, the base station determines whether a service flow is generated in step 301. In other words, the base station checks whether a new service flow is started to perform communication.

When the service flow is generated, the base station proceeds to step 303 to check whether the deactivation or activation of the HARQ scheme is requested from the terminal. Here, the HARQ activation request or the HARQ deactivation request is performed through message transmission or through physical signal sequence transmission. If the HARQ activation is requested, the base station proceeds to step 305, if the HARQ deactivation is requested, the base station proceeds to step 313.

If the HARQ activation is requested, the base station proceeds to step 305 to activate the HARQ scheme for the service flow. That is, the base station is set to apply the HARQ technique to the service flow.

After activating the HARQ scheme, the base station proceeds to step 307 and transmits a HARQ activation response to the terminal. In other words, the base station transmits a message or signal indicating that activation of the HARQ scheme for the service flow is completed.

After transmitting the HARQ activation response, the base station proceeds to step 309 to perform communication with the HARQ scheme enabled. Accordingly, the base station allocates resources for ACK / NACK feedback to the service flow and performs buffering for data packet retransmission.

Thereafter, the base station proceeds to step 311 and checks whether the deactivation of the HARQ scheme is requested from the terminal. Here, the HARQ deactivation request is performed through message transmission or through physical signal sequence transmission.

If the deactivation of the HARQ scheme is requested, the base station proceeds to step 313 to deactivate the HARQ scheme for the service flow. That is, the base station is set not to apply the HARQ scheme for the service flow.

After deactivating the HARQ scheme, the base station proceeds to step 315 and transmits a HARQ deactivation response to the terminal. In other words, the base station transmits a message or signal indicating that deactivation of the HARQ scheme for the service flow is completed.

After transmitting the HARQ deactivation response, the base station proceeds to step 317 to perform communication with the HARQ scheme deactivated. Accordingly, the base station does not allocate resources for ACK / NACK feedback to the service flow, and does not perform buffering for data packet retransmission.

In step 311, the base station determines whether activation of the HARQ scheme is requested from the terminal. Here, the HARQ activation request is performed through message transmission or through physical signal sequence transmission. If activation of the HARQ scheme is requested, the base station returns to step 305.

4 is a block diagram of a terminal in a broadband wireless communication system according to an exemplary embodiment of the present invention.

As shown in FIG. 4, the terminal includes a radio frequency (RF) processor 402, an OFDM communication unit 404, a channel quality measuring unit 406, a message interpreter 408, a data buffer 410, and a message generator ( 412, an error checker 414, and a HARQ controller 416.

The RF processor 402 performs a mutual conversion function between an RF band signal and a baseband signal transmitted and received through an antenna. That is, the RF processor 402 down-converts an RF band signal received through an antenna to a baseband signal, and then provides the baseband signal to the OFDM communicator 404 and from the OFDM communicator 404. After the baseband signal is up-converted into an RF band signal, the RF band signal is transmitted through an antenna.

The OFDM communication unit 404 performs a mutual conversion function between the baseband signal and the information bit string according to the OFDM scheme. That is, the OFDM communication unit 404 restores the information bit string by performing cyclic prefix removal (CP), fast fourier transform (FFT) operation, and demodulation on the received signal. The OFDM communication unit 404 configures OFDM symbols by performing modulation, inverse fast fourier transform (IFFT) operation, CP insertion, and the like on the transmission bit stream.

The channel quality measuring instrument 406 measures a channel quality with a base station using a signal of a predetermined type such as a preamble, a pilot, and the like. For example, the channel quality is measured in the form of RSSI or CINR. In addition, the channel quality measurer 406 calculates an electric field strength index using the RSSI or the CINR, and provides the electric field strength index to the HARQ controller 416. The message interpreter 408 interprets the control message received from the base station and provides the HARQ controller 416 with information confirmed through the control message. The data buffer 410 temporarily stores data transmitted and received. The message generator 412 generates a message sent to the base station. For example, the message generator 412 generates ACK / NACK under the control of the HARQ controller 416, and in particular, generates a message for requesting HARQ activation or request for HARQ deactivation. The error checker 414 performs an error check on the data packet received from the base station and informs the HARQ controller 416 of the error check result.

The HARQ controller 416 performs a function for performing a HARQ scheme. For example, when the HARQ scheme is activated, the HARQ controller 416 controls the message generator 412 to generate ACK / NACK according to the error check result of the error checker 414. In particular, the HARQ controller 416 performs a function for activating or deactivating the HARQ scheme according to the electric field strength.

In detail, when generating a service flow, the HARQ controller 416 requests HARQ activation or HARQ deactivation according to the field strength indicator provided from the channel quality measurer 406. That is, when the field strength indicator is smaller than a threshold, the HARQ controller 416 controls the message generator 412 to generate a message for the HARQ activation request, and the field strength indicator is greater than or equal to a threshold. In this case, the HARQ controller 416 controls the message generator 412 to generate a message for the HARQ deactivation request. Subsequently, when the state of the electric field strength indicator is kept above the threshold for a predetermined time period during the communication through the service flow while the HARQ scheme is activated, the HARQ controller 416 generates a message for requesting HARQ deactivation. The message generator 412 to control. In addition, if the electric field strength indicator decreases below a threshold while performing communication through a service flow with the HARQ scheme deactivated, the HARQ controller 416 generates the message for the HARQ activation request by the message generator 412. To control.

After requesting the HARQ activation or the HARQ deactivation, the HARQ controller 416 checks whether the HARQ activation response or HARQ deactivation response has been received by the message interpreter 408 from the base station. Accordingly, when notified that the HARQ activation response or the HARQ deactivation response has been received, the HARQ controller 416 activates or deactivates a HARQ scheme according to the HARQ activation response or the HARQ deactivation response.

In the configuration of the terminal described with reference to FIG. 4, the HARQ activation request and the HARQ deactivation request are performed by transmitting a message generated by the message generator 412. However, according to another embodiment of the present invention, the HARQ activation request and the HARQ deactivation request may be performed by transmitting a physical signal sequence. In this case, although not shown, the terminal further includes a 'sequence generator', wherein the HARQ controller 416 controls the sequence generator when a HARQ activation request or a HART deactivation request is performed, and the sequence generator is the HARQ controller 416. A sequence for HARQ activation or a sequence for HARQ deactivation is generated under the control of.

5 is a block diagram of a base station in a broadband wireless communication system according to an exemplary embodiment of the present invention.

As shown in FIG. 5, the base station includes an RF processor 502, an OFDM communication unit 504, a message interpreter 506, a data buffer 508, a message generator 510, and a HARQ controller 512. Configure.

The RF processor 502 performs a mutual conversion function between an RF band signal and a baseband signal transmitted and received through an antenna. That is, the RF processor 502 down-converts an RF band signal received through an antenna to a baseband signal, and then provides the baseband signal to the OFDM communicator 504 and from the OFDM communicator 504. After the baseband signal is up-converted into an RF band signal, the RF band signal is transmitted through an antenna.

The OFDM communication unit 504 performs a mutual conversion function between the baseband signal and the information bit string according to the OFDM scheme. That is, the OFDM communication unit 504 recovers the information bit string by performing CP removal, FFT operation, demodulation, etc. on the received signal. The OFDM communicator 504 configures OFDM symbols by performing modulation, IFFT operation, CP insertion, etc. on the transmission bit stream.

The message interpreter 506 interprets the control message received from the terminal, and provides the HARQ controller 512 with information confirmed through the control message. In particular, the message interpreter 506 checks the message for the HARQ activation request or HARQ deactivation request received from the terminal. The data buffer 508 temporarily stores data transmitted and received. The message generator 510 generates a message transmitted to the base station. For example, the message generator 510 generates a HARQ activation response message or a HARQ deactivation response message indicating completion of activation or deactivation of a HARQ scheme under the control of the HARQ controller 512.

The HARQ controller 512 performs a function for performing a HARQ scheme. For example, when the HARQ scheme is activated, the HARQ controller 512 stores the data packet transmitted for retransmission in the data buffer 508 and retransmits the stored data packet according to ACK / NACK from the terminal. . In particular, the HARQ controller 512 performs a function for activating or deactivating the HARQ scheme according to a request of the terminal.

In detail, when the HARQ activation request message is confirmed by the message interpreter 506, the HARQ controller 512 activates the HARQ scheme for the corresponding service flow and generates the HARQ activation response message. 510 is controlled. In addition, when the HARQ deactivation request message is confirmed by the message interpreter 506, the HARQ controller 512 deactivates the HARQ scheme for the corresponding service flow and generates the HARQ deactivation response message. To control.

In the configuration of the base station described with reference to FIG. 5, the HARQ activation request and the HARQ deactivation request are recognized through confirmation of a HARQ activation request message or a HARQ deactivation request message by the message interpreter 506. However, according to another embodiment of the present invention, the HARQ activation request and the HARQ deactivation request may be performed by transmitting a physical signal sequence. In this case, although not shown, the base station further includes a 'sequence detector', wherein the sequence detector detects a sequence for HARQ activation or a sequence for HARQ deactivation, and the HARQ controller 416 is a sequence of the sequence detector. The HARQ scheme is activated or deactivated according to the detection result.

Meanwhile, in the detailed description of the present invention, specific embodiments have been described, but various modifications are possible without departing from the scope of the present invention. Therefore, the scope of the present invention should not be limited to the described embodiments, but should be determined not only by the scope of the following claims, but also by the equivalents of the claims.

1 is a diagram illustrating signal exchange according to adaptive HARQ (Hybrid Automatic Repeat reQuest) operation in a broadband wireless communication system according to an embodiment of the present invention;

2 is a diagram illustrating an operation procedure of a terminal in a broadband wireless communication system according to an embodiment of the present invention;

3 is a diagram illustrating an operation procedure of a base station in a broadband wireless communication system according to an embodiment of the present invention;

4 is a block diagram of a terminal in a broadband wireless communication system according to an embodiment of the present invention;

5 is a block diagram of a base station in a broadband wireless communication system according to an exemplary embodiment of the present invention.

Claims (16)

In the method of operating a terminal in a broadband wireless communication system, Calculating a field strength indicator representing the field strength when the service flow is generated; Requesting activation of a hybrid automatic repeat request (HARQ) scheme for the service flow when the electric field strength indicator is smaller than a threshold; If the field strength indicator is greater than or equal to the threshold, requesting deactivation of a HARQ scheme for the service flow. The method of claim 1, The electric field strength indicator is calculated using at least one of a received signal strength indicator (RSSI) and a carrier to interference and noise ratio (CINR). The method of claim 2, The request for activation of the HARQ scheme or the request for deactivation of the HARQ scheme is performed through message transmission or physical signal sequence transmission. The method of claim 3, Requesting deactivation of the HARQ scheme for the service flow when the field strength indicator is continuously greater than or equal to the threshold for a predetermined time period while performing the communication through the service flow while the HARQ scheme is activated. And further comprising a process of doing. The method of claim 3, Requesting activation of the HARQ scheme for the service flow when the electric field strength indicator becomes smaller than the threshold while performing communication through the service flow with the HARQ scheme deactivated. . A method of operating a base station in a broadband wireless communication system, When the service flow is generated, checking an activation request or a deactivation request for a hybrid automatic repeat request (HARQ) scheme from a terminal; When the activation of the HARQ scheme is requested, activating a HARQ scheme for the service flow; If the deactivation of the HARQ scheme is requested, deactivating a HARQ scheme for the service flow. The method of claim 6, The request for activation of the HARQ scheme or the request for deactivation of the HARQ scheme is performed through message transmission or physical signal sequence transmission. The method of claim 7, wherein Activating the HARQ scheme for the service flow when activation of the HARQ scheme is requested while performing communication through the service flow while deactivating the HARQ scheme; And deactivating the HARQ scheme during the communication through the service flow while activating the HARQ scheme, and deactivating the HARQ scheme for the service flow. A terminal device in a broadband wireless communication system, A measuring device for calculating an electric field strength index indicating electric field strength when generating a service flow; If the field strength indicator is less than a threshold, request activation of a hybrid automatic repeat reQuest (HARQ) scheme for the service flow; if the field strength indicator is greater than or equal to the threshold, deactivate the HARQ scheme for the service flow. And a controller for requesting the request. 10. The method of claim 9, Wherein the electric field strength indicator is calculated using at least one of a received signal strength indicator (RSSI) and a carrier to interference and noise ratio (CINR). The method of claim 10, The request for activation of the HARQ scheme or the request for deactivation of the HARQ scheme is performed through message transmission or physical signal sequence transmission. The method of claim 11, When the controller maintains the state of the electric field strength indicator that is greater than or equal to the threshold for a predetermined time period while performing communication through the service flow with the HARQ scheme activated, the HARQ scheme for the service flow. Requesting deactivation of the device. The method of claim 11, And the controller requests activation of the HARQ scheme for the service flow when the electric field strength indicator becomes smaller than the threshold while performing communication through the service flow with the HARQ scheme deactivated. A base station apparatus in a broadband wireless communication system, An interpreter for identifying an activation request or a deactivation request for a hybrid automatic repeat request (HARQ) scheme from a terminal when generating a service flow; And a controller for activating the HARQ scheme for the service flow when the activation of the HARQ scheme is requested and deactivating the HARQ scheme for the service flow when the deactivation of the HARQ scheme is requested. The method of claim 14, The request for activation of the HARQ scheme or the request for deactivation of the HARQ scheme is performed through message transmission or physical signal sequence transmission. The method of claim 15, When the controller requests the activation of the HARQ scheme during communication through the service flow while deactivating the HARQ scheme, the controller activates the HARQ scheme for the service flow and activates the HARQ scheme. During the communication through the flow, if the deactivation of the HARQ scheme is requested, the apparatus characterized in that for deactivating the HARQ scheme for the service flow.

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