KR101038144B1 - Method for controlling power of mobile station and base station supporting the method - Google Patents

Abstract

The present invention relates to a power control method of a terminal in a broadband wireless communication system, and more particularly, to a power control method and a base station supporting the terminal when the initial network entry, network reentry, and transition from the inactive state to the active state.

In a power control method of a terminal according to an embodiment of the present invention, in a power control method of a terminal in a wireless communication system, a power control response (PMC_RSP) message including power offset value information to be set in a terminal is transmitted to the terminal. First step; Check whether a response to the power control response message has been received from the terminal for a preset time, and even if a response to the power control response message is not received from the terminal, or if a response from the terminal is received, the response is not known. Determining a retransmission of the power control response message when including equation information; And retransmitting the power control response message to the terminal according to the retransmission determination result.

Handover, ranging, power control, terminal, base station

Description

Method for controlling power of a terminal and a base station supporting the same {Method for controlling power of mobile station and base station supporting the method}

The present invention relates to a method for power control of a terminal in a broadband wireless communication system, and in particular, initial network entry, network reentry and idle mode (sleep mode). The present invention relates to a power control method of a terminal when switching to an active state and a base station supporting the same.

Recently, various researches have been conducted on a communication system capable of providing a user with a communication service that guarantees a transmission speed of 100 Mbps, mobility, and various quality of service (QsS). Among them, the IEEE 802.16 technical standard is a representative communication system. There is a broadband wireless communication system based.

A broadband wireless communication system based on the IEEE 802.16 technical standard includes a plurality of terminals (MS), a base station (BS), and a control station (ACR), and data transmission and reception between the terminal and the base station is performed by orthogonal frequency division multiplexing (OFDM) and OFDMA. (Orthogonal Frequency Division Multiple Access) scheme. Since the broadband wireless communication system uses an OFDM / OFDAM scheme, high-speed data transmission is possible using a plurality of subcarriers, and supports mobility of a terminal through a multi-cell structure. .

In a broadband wireless communication system, a terminal needs to enter a network area, that is, a cell area under the jurisdiction of a base station in order to receive a communication service, and the entry into a cell area under the control of a base station is performed by performing a ranging procedure. The ranging procedure is performed when the terminal powers on for the first time or the terminal enters the handover area by moving from the serving base station area where the service is currently being performed.

The ranging procedure for initial network entry and handover is performed by exchanging a ranging request (RNG_REQ) message and a ranging response (RNG_RSP) message between the terminal and the base station.

Herein, the ranging request (RNG_REQ) message and the ranging response (RNG_RSP) message include information of neighbor nodes such as MAC address, preamble index, and reception strength in the form of TLV (Type / Length / Value). The MS may be started by first sending a ranging request (RNG_REQ) message to the BS, and the BS may be started by sending a ranging response (RNG_RSP) message to the MS. For example, the terminal transmits a ranging request (RNG_REQ) message to the base station to join the cell of the base station, and the base station receiving the ranging request (RNG_REQ) message from the terminal in response to the ranging response (RNG_RSP) By sending a message to the terminal to set the frequency and time correction value to join the terminal to its cell.

After the ranging procedure, a power control procedure for sending and receiving a power control request (PMC_REQ) message and a power control response (PMC_RSP) message between the terminal (MS) and the base station (BS) is performed. Will perform. Further, even when the handover and the UE are switched from the inactive state (idle mode, sleep mode) to the active state, the power control procedure is performed using the above-described power control messages PMC_REQ and PMC_RSP.

According to the conventional power control method of the terminal, if the base station does not receive the power control request (PMC_REQ) message from the terminal or the terminal does not receive the power control response (PMC_RSP) message from the base station, the power control procedure is performed. There is a problem that can not set the power offset value of the terminal can not be performed.

The IEEE 802.16 technical standard does not provide for the retransmission of power control messages PMC_REQ and PMC_RSP in case of transmission / reception errors. As a result, when the transmission and reception of the power control (PMC_REQ, PMC_RSP) message fails, the power control procedure cannot be performed smoothly, and thus, a power offset value of the terminal cannot be set.

The present invention is to solve the above-described problem, the present invention according to the embodiment is a power control method for enabling the retransmission of the power control request (PMC_REQ) message and power control response (PMC_RSP) message for power control of the terminal and the same It is a technical problem to provide a supporting base station.

The present invention provides a power control method for smoothly performing a power control procedure by guaranteeing transmission and reception of power control (PMC_REQ, PMC_RSP) messages for power control between a base station and a user equipment, and another technology. It is a task.

Another object of the present invention is to provide a power control method capable of reducing time for power control of a terminal.

The power control method of a terminal according to an embodiment of the present invention for solving the above problems is a power control response (PMC_RSP) including the power offset value information to be set in the terminal in the power control method of the terminal in a wireless communication system A first step of transmitting a message to the terminal; Check whether a response to the power control response message has been received from the terminal for a preset time, and even if a response to the power control response message is not received from the terminal, or if a response from the terminal is received, the response is not known. Determining a retransmission of the power control response message when including equation information; And retransmitting the power control response message to the terminal according to the retransmission determination result.

In the power control method of a terminal according to an embodiment of the present invention for solving the above-described problems, a power control request (PMC_REQ) including power offset value information to be set in a terminal in a power control method of a terminal in a wireless communication system Transmitting a message to a base station; Check whether a response to the power control request message has been received from the base station for a preset time, and if the response to the power control request message is not received from the base station, or if a response from the base station is received, the response is not known. Determining a retransmission of the power control request message when including equation information; And retransmitting the power control request message to the base station according to the retransmission determination result.

A base station according to an embodiment of the present invention for solving the above-described problem, in a base station providing a wireless communication service to a terminal, confirms whether a power control request message is received from the terminal, and according to a result of the confirmation, the power control response message A retransmission control unit for determining whether to perform retransmission and generating retransmission information; An MCS level setting unit for setting an MCS level applied to the terminal according to a channel state of the terminal and retransmission information from the retransmission controller; And a scheduler constituting a frame transmitted to the terminal according to information from the retransmission control unit and the MCS level setting unit.

The retransmission control unit of the base station according to an embodiment of the present invention includes a message confirmation unit for confirming the response of the power control request message transmitted from the terminal; A timer for generating time information serving as a criterion for determining whether a response from the terminal is received during a preset response waiting time; And a retransmission information generator configured to generate retransmission information of the power control response message when the response from the terminal is not received during a preset response waiting time by using the time information from the timer.

The power control method of a terminal and a base station supporting the same according to an embodiment of the present invention enable a smooth power control by clarifying a retransmission procedure of a power control (PMC_REQ, PMC_RSP) message for power control between a base station and a terminal.

The power control method and the base station supporting the same ensure a transmission and reception of the power control (PMC_REQ, PMC_RSP) message for power control between the base station and the terminal to enable smooth power control.

A power control method of a terminal and a base station supporting the same according to an embodiment of the present invention provide an effect of quickly setting power control between a base station and a terminal.

According to an embodiment of the present invention, when a power control (PMC_REQ, PMC_RSP) message for setting a power offset value of a terminal fails to be transmitted, the power control service of the terminal is guaranteed by providing a retransmission method of the power control message.

The present invention according to the embodiment ensures the power control service of the terminal by setting the retransmission cycle and the number of retransmission of the power control (PMC_REQ, PMC_RSP) message through a retransmission control unit including a timer and a retransmission counter.

Hereinafter, various embodiments of the present disclosure will be described with reference to the accompanying drawings.

Prior to the description with reference to the drawings, the initial network (initial network) entry process according to the IEEE 802.16 standard will be briefly described.

The network entry process according to the IEEE 802.16 standard includes a network topology advertisement process for informing all terminals in a cell of information related to a base station, and a neighbor base station scanning process for measuring channel quality of a neighbor base station based on the information. MSS scanning of neighbor BS), and optionally association procedures for matching power offset values of base stations and terminals, time difference values for synchronization, and the like, are performed sequentially. Will be entered normally.

The network entry process is performed through a ranging procedure, in which the terminal transmits a ranging request (RNG_REQ) message to the base station and performs a ranging request, and the base station receives the ranging request (RNG_REQ) message from the terminal. In response, the base station transmits a ranging response (RNG_RSP) message to the terminal, or the base station first transmits a ranging response (RNG_RSP) message to the terminal, and in response, the terminal transmits a ranging request (RNG_REQ) message to the base station. do.

After the ranging procedure using the ranging request (RNG_REQ) message and the ranging response (RNG_RSP) message, the terminal and the base station exchange power control messages (PMC_REQ, PMC_RSP) between the base station and the power control procedure, thereby performing a power control procedure. Set the offset value.

FIG. 1 is a diagram illustrating a configuration of a base station supporting a power control method of a terminal according to an exemplary embodiment of the present disclosure, and FIG. 2 is a diagram illustrating a configuration of a retransmission control unit illustrated in FIG. 1.

Hereinafter, a base station 100 supporting a power control method of a terminal according to an embodiment of the present invention will be described with reference to FIGS. 1 and 2. Here, the base station 100 refers to a serving base station upon initial network entry, and refers to a target base station during handover. However, the present invention is not limited thereto, and other base stations of the network may play the same role in addition to the serving base station and the target base station, and thus may include the same components as the base station according to the embodiment of the present invention.

As shown in FIG. 1, the base station 100 supporting the power control method of the terminal according to an exemplary embodiment of the present invention includes an interface 110, a band signal processor 120, a transmitter 130, and an antenna ( 140, a scheduler 150, a receiver 160, and a retransmission controller 200.

In the reception path, the receiver 160 receives the radio signal transmitted by the terminal through the antenna 140 and converts it into a baseband signal. For example, the receiver 160 removes and amplifies the noise from the above-described signal for data reception of the base station, down-converts the amplified signal to a baseband signal, and digitizes the down-converted baseband signal.

The band signal processor 120 extracts information or data bits from the digitized signal to perform demodulation, decoding, and error correction processes. The received information and data may be transmitted to the adjacent wired / wireless network via the interface 110 or may be transmitted to another terminal serviced by the base station through a transmission path.

In the transmission path, the interface 110 receives voice, data, or control information from a control station or a wireless network, and the band signal processor 120 encodes voice, data, or control information and outputs the encoded information to the transmitter 130. do. The transmitter 130 modulates the encoded voice, data, or control information into a carrier signal having a desired transmission frequency or frequencies, amplifies the modulated carrier signal to a level suitable for transmission, and propagates to the air through the antenna 140. do.

The scheduler 150 controls the operation of the reception path and the transmission path and each component. In addition, the scheduler 150 configures a frame to be transmitted to each terminal in the transmission path and maps the corresponding burst. Thereafter, the burst-mapped frame is transmitted to the band signal processor 120.

The MCS level setting unit 170 sets a modulation scheme and a code rate according to a signal-to-noise ratio (SNR) received for each subcarrier. The MCS level setting unit 170 selects a higher order modulation method such as a low code rate channel coding and a 64-QAM (Quadrature Amplitude modulation) modulation method that can simultaneously transmit multiple bits for a subcarrier having a good channel environment. For this poor subcarrier, a low order modulation scheme such as channel coding with high code rate and binary phase shift keying (BPSK) modulation scheme is selected.

In order to apply the above-described MCS, each terminal measures the SNRs of the signals transmitted through the downlink for each subcarrier, transmits them to the base station through the uplink, and the base station determines the MCS level of each terminal by looking at them. . The MCS level setting unit 170 may change the MCS level set for each terminal according to retransmission information from the retransmission control unit 200 when retransmission of the power control response (PMC_RSP) message is performed.

Specifically, the retransmission message is a case where the previous transmission has failed, and the MCS level should be adjusted downward in order to reduce the probability of the message transmission failure during retransmission. The MCS level setting unit 170 uses the retransmission information provided by the retransmission counter 230 to set the MCS level lower than the MCS level applied during the previous transmission. The level will be set to the lowest level (eg QPSK 1/2 Rep6). In the foregoing description and in FIG. 1, the MCS level setting unit 170 is described in a configuration provided separately in the base station 100, but the MCS level setting unit 170 may be included in other components (eg, a scheduler) in the base station. have.

As an example of adjusting the MCS level, the MCS level determines the MCS level to be transmitted by the base station according to the signal quality of the terminal. When retransmission is performed once, the MCS level is determined according to the channel state (signal quality) of the terminal. The lower MCS level can be selected from the level and the reference MCS level (QPSK 1/2) and applied to the retransmission step.

Here, since the downscaling of the MCS level failed to transmit the power control response (PMC_RSP) message in the previous transmission step, the transmission may fail if the power control response (PMC_RSP) message is retransmitted by applying the same MCS level. Because of. In order to prevent this, in the retransmission step, the MCS level is adjusted downward to increase the transmission success probability of the power control response (PMC_RSP) message.

The retransmission control unit 200 confirms whether the transmission of the power control response (PMC_RSP) message transmitted to the terminal through the message received from the terminal via the interface 110, and the power control response (PMC_RSP) according to the confirmation result Determines whether to resend the message. In addition, when retransmission of the power control response (PMC_RSP) message is determined, retransmission information is generated to change the MCS level set in the terminal, and the generated retransmission information is transmitted to the scheduler 150. To this end, the retransmission controller 200 includes a message confirmation unit 210, a timer 220, a retransmission counter 230, a determination unit 240, and a retransmission information generation unit 250 as shown in FIG. 2. .

The message acknowledgment unit 210 checks whether a power control request (PMC_REQ) message received from the terminal is received and a response signal for the power control response (PMC_RSP) message transmitted to the terminal, and transmits the confirmation result to the timer 220 and the retransmission. Send to the counter 230.

The timer 220 receives the transmission information of the power control response (PMC_RSP) message transmitted to the terminal from the transmitter 130, and then operates the timer to receive the response from the terminal during the set time, that is, the response waiting time (T_PMC_BS). The reference time information on the response from the terminal is provided to the determination unit 240 so that the determination unit 240 can determine whether or not it is determined. In more detail, the timer 220 operates after the power control response (PMC_RSP) message is transmitted to the terminal, so that the response waiting time (ACK, PMC_REQ) for the power control response (PMC_RSP) message is preset. The determination unit 240 generates time information so that the determination unit 240 determines whether or not it is received during the T_PMC_BS, and provides it to the determination unit 240.

The timer operated after the transmission of the power control response (PMC_RSP) message is terminated when a response (ACK, PMC_REQ) to the power control response (PMC_RSP) message is received from the terminal.

Here, the response waiting time (T_PMC_BS) can be variably set to a value of 0 or more (for example, 0 <T_PMC_BS ≤ 65535 [ns]), and retransmission of the power control response (PMC_RSP) message according to the setting value of the response waiting time. The period of is changed.

The retransmission counter 230 counts the number of transmissions of the power control response (PMC_RSP) message based on the transmission information of the power control response (PMC_RSP) message input from the transmitter 130, and the determination unit 240 controls the power to be retransmitted. The retransmission count information is provided to the determination unit 240 so as to determine whether the retransmission count of the response (PMC_RSP) message satisfies the preset maximum retransmission count.

The retransmission count counted by the retransmission counter 230 is reset to an initial value when a response (ACK, PMC_REQ) to the power control response (PMC_RSP) message transmitted to the terminal is received.

The retransmission count information provided by the retransmission counter 230 is used to adjust the MCS level by the MCS level setting unit 170 of the scheduler 150 when retransmitting the power control response (PMC_RSP) message. Specifically, the retransmission message is a case where the previous transmission has failed, and the MCS level should be adjusted downward in order to reduce the probability of the message transmission failure during retransmission. At this time, the retransmission count information provided by the retransmission counter 230 is used. When retransmission of the power control response (PMC_RSP) message is performed to the same terminal once, the MCS level lower than the MCS level applied in the previous transmission is set, and when the retransmission is performed more than once, the MCS level is the lowest level (for example, QPSK). 1/2 Rep6).

Here, the maximum number of retransmissions (CNT_BS) set in advance may be variably set to one or more values (for example, 0 <CNT_BS ≤ 65535), and if the set value of the maximum number of retransmissions is set to infinity (∞) from the terminal The power control response (PMC_RSP) message is retransmitted until a response (ACK, PMC_REQ) to the power control response (PMC_RSP) message is received.

The determination unit 240 determines whether to retransmit the power control response (PMC_RSP) message by using the time information from the timer 220. In more detail, the determination unit 240 transmits information of the power control response (PMC_RSP) message included in the time information from the retransmission counter 230, response time information from the terminal, and response waiting time (T_PMC_BS). Information may be used to determine whether to retransmit the power control response (PMC_RSP) message. That is, when there is no response to the power control response (PMC_RSP) message transmitted to the terminal during the preset response waiting time (T_PMC_BS), it determines the retransmission of the power control response (PMC_RSP) message, and determines the retransmission information generation unit ( 250).

In addition, the determination unit 240 may use the retransmission count information from the retransmission counter 230 in determining the retransmission of the power control response (PMC_RSP) message. If the number of retransmissions of the current Power Control Response (PMC_RSP) message to be retransmitted does not exceed the preset maximum number of retransmissions, retransmission is determined, and the number of retransmissions of the Power Control Response (PMC_RSP) messages to be retransmitted is preset maximum retransmission. If the number of times is exceeded, it is determined that the retransmission of the power control response (PMC_RSP) message is abandoned.

The determination result is transmitted to the retransmission information generation unit 250. At this time, the information on the number of retransmissions of the power control response (PMC_RSP) message to be retransmitted is transmitted together with the determination result transmitted to the retransmission information generation unit 250. Here, the information on the number of retransmissions is used to set the MCS level when retransmission of the power control response (PMC_RSP) message.

The retransmission information generator 250 generates retransmission information of the power control response (PMC_RSP) message by using the retransmission determination result from the determination unit 240 and transmits the generated retransmission information to the scheduler 150. The scheduler 150 performs scheduling of the power control response (PMC_RSP) message according to the retransmission information from the retransmission information generation unit 250, and the MCS level setting unit when the retransmission information includes information on the adjustment of the MCS level. The MCS level applied to the transmission of the power control response (PMC_RSP) message can be adjusted through 170.

In the foregoing description, the retransmission control unit 200 is illustrated and described as being included in the base station 100, but the retransmission control unit 200 may be included in the terminal as well as the base station 100.

When the retransmission control unit 200 is included in the terminal, the message confirming unit 210 confirms the message received from the base station 100, and the retransmission information generating unit 250 requests the power control to which the retransmission is performed to the base station 100. (PMC_REQ) Creates information about retransmission of a message. After transmitting the power control request (PMC_REQ) message to the base station 100, the timer 220 operates, and the response waiting time for the response (ACK, PMC_RSP) to the power control request (PMC_REQ) message transmitted to the base station is preset. If it is not received during this time, it decides to retransmit the Power Control Request (PMC_REQ) message. In addition, in determining the retransmission of the power control request (PMC_REQ) message, the terminal may use the retransmission count information from the retransmission counter 230 in the same manner as the base station 100 described above.

Next, a power control method of the terminal using the base station 100 described above with reference to FIGS. 3 to 5 will be described.

Prior to the description with reference to the drawings, when the power control method of the terminal according to the first embodiment of the present invention does not receive a response (ACK, PMC_REQ) from the terminal to the power control response (PMPC_RSP) message transmitted from the base station to the terminal The present invention relates to a retransmission method of a power control response (PMPC_RSP) message transmitted from a base station to a terminal.

The power control method of the terminal according to the first embodiment of the present invention may be applied when the terminal initially enters the network, performs a handover, and the terminal is switched from an inactive state to an active state.

First, referring to FIG. 3, a ranging procedure is performed by exchanging a ranging request (RNG_REQ) message and a ranging response (RNG_RSP) message between a terminal MS and a base station BS (S100). The ranging procedure may be started by the terminal first transmitting a ranging request (RNG_REQ) message to the base station, and the base station BS may be started by transmitting a ranging response (RNG_RSP) message to the terminal.

After the ranging procedure of S100, the base station transmits a power control response (PMC_RSP) message including the power offset value information to the terminal (S110). In this case, transmission information of the power control response (PMC_RSP) message is provided to the retransmission control unit 200 shown in FIG. 2.

Thereafter, the retransmission control unit 200 having received the message transmission information operates the timer 220 (S120) to determine whether a response (ACK, PMC_REQ) to the power control response (PMC_RSP) message transmitted to the terminal is received for a preset time. Check whether or not.

Thereafter, when the response message for the power control response (PMC_RSP) message transmitted to the terminal is not received from the terminal for a preset time, the power control response (PMC_RSP) message is retransmitted to the terminal (S130).

Here, the retransmission period of the power control response (PMC_RSP) message retransmitted to the terminal is determined according to the response waiting time set in the timer 220, and the number of retransmissions is determined according to the maximum retransmission number set in the retransmission counter 230. In addition, the MCS level may be adjusted according to the number of retransmissions, which will be described with reference to FIG. 4.

After retransmission of the power control response (PMC_RSP) message of S130, although not shown in the figure, the operation of the timer of S120 is performed in the same manner to determine whether a response (ACK, PMC_REQ) is received from the terminal for a preset time.

After retransmitting the power control response (PMC_RSP) message through the above-described procedure, when receiving the power control request (PMC_REQ) message or ACK from the terminal (S140), all information for setting the power offset value of the terminal between the terminal and the base station is successfully completed. Since the transmission and reception, the power control procedure of the terminal is completed by setting the power offset value of the terminal according to the information included in the power control messages.

In the above description, the base station first transmits a power control response (PMC_RSP) message to the terminal, but the power control procedure is performed. However, as shown in S105, the terminal first transmits a power control request (PMC_REQ) message to the base station for power control. The procedure can be performed.

4, the power control method of the terminal according to the first embodiment of the present invention will be described in detail.

First, when transmitting a power control response (PMC_RSP) message from the base station (BS) to the terminal (MS), it is determined whether the initial transmission (S300).

In this case, the power control response (PMC_RSP) message transmitted to the terminal may be transmitted from the base station to the terminal first to set the power offset value to the terminal as described above, or the response of the power control request (PMC_REQ) message received from the terminal. You can send it as a message.

As a result of checking in S300, if it is the initial transmission, the MCS level for the initial transmission is set (S310), and a power control response (PMC_RSP) message is transmitted to the terminal (S320).

Thereafter, the device waits for receiving a response message for the power control response (PMC_RSP) message transmitted to the terminal for a preset response waiting time (S330).

Thereafter, it is determined whether to retransmit the power control response (PMC_RSP) message (S340). Here, the determination of whether to retransmit is determined according to whether the response message (PMC_REQ) is received from the terminal for a predetermined time and whether the received message is ACK or NACK.

As a result of the determination of S340, when the response message (PMC_REQ) is received from the terminal, or when the ACK is received, the power control message (PMC_REQ,) transmitted and received between the terminal and the base station without performing the retransmission procedure of the power control response (PMC_RSP) message A power offset value of the terminal is set according to the power control information included in the PMC_RSP (S350) to complete the power control procedure of the terminal.

Returning to step S340, as a result of the determination, when retransmission of the power control response (PMC_RSP) message is necessary, that is, a response to the power control response (PMC_RSP) message transmitted to the terminal has not been received for a preset time, or is a response received from the terminal. In the case of this NACK, a power control response (PMC_RSP) message must be retransmitted in order to set a power offset value in the terminal.

Before performing retransmission of the power control response (PMC_RSP) message, it is first checked whether the number of retransmissions of the power control response (PMC_RSP) message to be retransmitted exceeds the preset maximum retransmission number (S390).

As a result of the check in S390, when the number of retransmissions of the control response (PMC_RSP) message exceeds the preset maximum number of retransmissions, this means that the number of retransmissions of the power control response (PMC_RSP) messages is preset by the number of times previously set in order to set the power offset value of the terminal. Despite this, the transmission of the power control response (PMC_RSP) message has failed to provide a smooth communication service to the terminal. In this case, since the power offset value for the corresponding terminal cannot be set, the power control setting is treated as a failure (S410).

On the other hand, if the number of retransmissions of the control response (PMC_RSP) message does not exceed the preset maximum retransmission number as a result of the confirmation of S390, the power control response (PMC_RSP) message may be retransmitted, so that the number of retransmissions is increased once (S400). , Check whether the current retransmission is the first retransmission (S360). Here, the confirming step of S360 is performed in the same way even when the confirmation result of S300 is not the initial transmission of the power control response (PMC_RSP) message.

As a result of checking in S360, if the first retransmission, the MCS level is adjusted downward so that the MCS level applied to the retransmission is lower than the MCS level applied in the previous transmission step (S370). Thereafter, the power control response (PMC_RSP) message is retransmitted to the terminal (S320) to perform a power control procedure of the terminal.

As an example of the MCS level down-regulation method, the MCS level determines the MCS level to be transmitted from the base station according to the signal quality of the terminal, the MCS level and the reference MCS level determined according to the channel state (signal quality) of the terminal ( Among the QPSK 1/2), a lower MCS level can be selected and applied to the retransmission step.

Here, since the downscaling of the MCS level failed to transmit the power control response (PMC_RSP) message in the previous transmission step, the transmission may fail if the power control response (PMC_RSP) message is retransmitted by applying the same MCS level. Because of. In order to prevent this, in the retransmission step, the MCS level is adjusted downward to increase the transmission success probability of the power control response (PMC_RSP) message.

If you retransmit the Power Control Response (PMC_RSP) message by adjusting the MCS level downward, the probability of successful transmission of the message is increased. Therefore, the power control time of the terminal can be reduced by preventing the situation of retransmitting the Power Control Response (PMC_RSP) message several times. have.

On the other hand, as a result of checking in S360, if the first retransmission is not adjusted, the MCS level applied to the retransmission is adjusted to the lowest MCS level applicable to the terminal (for example, QPSK 1/2 Rep6) (S380). Here, adjusting the MCS level from the second retransmission to the lowest MCS level applicable to the terminal is performed even though the MCS level is adjusted downward as in S370 in the previous transmission step, transmission of the power control response (PMC_RSP) message is not performed. In the second retransmission step, the transmission success probability of the PMC_RSP message is higher than the first retransmission step.

Thereafter, the power control response (PMC_RSP) message is retransmitted to the terminal (S320) to perform a power control procedure of the terminal.

Next, a power control method of the terminal according to the second embodiment of the present invention will be described with reference to FIG. 5.

Prior to the description with reference to the drawings, the power control method of the terminal according to the second embodiment of the present invention when the response (ACK, PMC_RSP) from the terminal to the power control request (PMPC_REQ) message transmitted from the terminal to the base station The present invention relates to a retransmission method of a power control request (PMPC_REQ) message transmitted from a terminal to a base station. The power control method of the terminal according to the second embodiment of the present invention may be applied when the terminal initially enters the network, performs a handover, and the terminal is switched from an inactive state to an active state.

Referring to FIG. 5, a ranging procedure is performed between a terminal MS and a base station BS through a ranging request (RNG_REQ) message and a ranging response (RNG_RSP) message (S200). The ranging procedure may be started by the terminal first transmitting a ranging request (RNG_REQ) message to the base station, and the base station BS may be started by transmitting a ranging response (RNG_RSP) message to the terminal.

After the ranging procedure of S200, the UE transmits a power control request (PMC_REQ) message including the power offset value information to be set to the base station (S120). When the terminal includes the retransmission control unit 200 shown in FIG. 2, the transmission information of the power control request (PMC_REQ) message is provided to the retransmission control unit 200 shown in FIG. 2.

Thereafter, the retransmission control unit 200 receiving the message transmission information operates the timer 220 (S220) to determine whether a response (ACK, PMC_RSP) to the power control request (PMC_REQ) message transmitted to the base station is received for a preset time. Check whether or not.

Thereafter, when the response message for the power control request (PMC_REQ) message transmitted to the base station is not received from the terminal for a preset time, the power control request (PMC_REQ) message is retransmitted to the base station (S230).

Here, the retransmission period of the power control request (PMC_REQ) message retransmitted to the base station is determined according to the response waiting time set in the timer 220, and the number of retransmissions is determined according to the maximum retransmission number set in the retransmission counter 230. The retransmission process according to the response wait time and the maximum number of retransmissions is the same as in the above-described first embodiment, and thus a detailed description thereof will be omitted.

After retransmission of the power control request (PMC_REQ) message of S230, although not shown in the figure, the operation of the timer of S220 is performed in the same manner to determine whether a response (ACK, PMC_REQ) is received from the base station for a preset time.

After retransmitting the power control request (PMC_REQ) message through the above-described procedure, when receiving a power control response (PMC_RSP) message or ACK from the base station (S240), all information for setting the power offset value of the terminal between the terminal and the base station is successfully completed. Since the transmission and reception, the power control procedure of the terminal is completed by setting the power offset value of the terminal according to the information included in the power control messages.

In the above description, the terminal first transmits a power control request (PMC_REQ) message to the terminal, but the power control procedure is performed. However, as shown in S205, the base station first transmits a power control response (PMC_RSP) message to the terminal for power control. The procedure can be performed.

The above-described power control method of the terminal may be implemented in the form of a program that can be executed using various computer means. A program for performing the power control method of the terminal may be read by a recording medium ( For example, a recording medium such as a hard disk, a CD-ROM, a DVD, a ROM, a RAM, or a flash memory. It also includes those implemented in the form of carrier waves (eg, transmission over the Internet). The computer-readable recording medium may be distributed and formed in a computer system connected via a network.

The configuration and operation as described above is not limited to the claims of the present invention as an embodiment, and various changes and modifications are possible within the scope of not changing the technical spirit of the present invention in the field to which the present invention belongs. It is obvious to those who are engaged.

It will be apparent to those skilled in the art that the present invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. Accordingly, the above detailed description should not be construed as limiting in all aspects and should be considered as illustrative. The scope of the invention should be determined by reasonable interpretation of the appended claims, and all changes within the equivalent scope of the invention are included in the scope of the invention.

1 is a view showing the configuration of a base station supporting a power control method of a terminal according to an embodiment of the present invention.

FIG. 2 is a diagram illustrating a configuration of a retransmission control unit shown in FIG. 1. FIG.

3 is a view showing a power control method of a terminal according to a first embodiment of the present invention.

4 is a flowchart illustrating a power control method of a terminal according to the first embodiment of the present invention.

5 is a view showing a power control method of a terminal according to a second embodiment of the present invention.

<Explanation of symbols for the main parts of the drawings>

100: base station 110: interface

120: band signal processor 130: transmitter

140: antenna 150: scheduler

152: MCS level setting unit 160: receiving unit

200: retransmission control unit 210: message confirmation unit

220: timer 230: retransmission counter

240: determination unit 250: retransmission information generation unit

Claims (18)

In the power control method of the terminal in a wireless communication system, A first step of transmitting a power control response (PMC_RSP) message including power offset value information to be set in a terminal to the terminal; Check whether a response to the power control response message has been received from the terminal for a preset time, and even if a response to the power control response message is not received from the terminal or if a response from the terminal is received, the response is not recognized. Determining a retransmission of the power control response message if it contains information; And And retransmitting the power control response message to the terminal according to the retransmission determination result. In a third step of retransmitting the power control response message, If the retransmission of the power control response message is the first retransmission, the MCS level applied at the retransmission is lowered to be lower than the MCS level applied at the initial transmission. If the power control response message is retransmitted more than once, the MCS level applied during retransmission is adjusted to the lowest level applicable to the terminal. If the MCS level is adjusted to the lowest level applicable to the terminal and the response of the power control response message is retransmitted and the response is not received or the response includes unrecognized information, the power control setting of the terminal is treated as a failure. Power control method of the terminal, characterized in that. The method of claim 1, wherein prior to said first step Receiving a power control request (PMC_REQ) message from the terminal, wherein the power control response message of the first step is a response of the power control request message. The method of claim 1, wherein in the second step Determining the number of retransmissions of the power control response message, and determining the retransmission of the power control response message when the number of retransmissions does not exceed a preset maximum number of retransmissions. delete delete The method of claim 3, wherein And if the retransmission of the power control response message is the first retransmission, adjusting the MCS level to a lower level among the MCS level and the reference MCS level determined according to the channel state of the terminal. delete delete The method of claim 1, wherein the second and third steps And the terminal is performed when the terminal enters the network, performs a handover, and switches from an inactive state to an active state. In the power control method of the terminal in a wireless communication system, A first step of transmitting a power control request (PMC_REQ) message including power offset value information to be set in a terminal to a base station; Check whether a response to the power control request message has been received from the base station for a preset time, and if the response to the power control request message is not received from the base station, or if a response from the base station is received, the response is not present. Determining a retransmission of the power control request message if it includes recognition information; And retransmitting the power control request message to the base station according to the retransmission determination result. In a third step of retransmitting the power control request message, If the retransmission of the power control request message is the first retransmission, the MCS level applied in the retransmission is lowered to be lower than the MCS level applied in the initial transmission, If the power control request message is retransmitted more than once, the MCS level applied at the time of retransmission is adjusted to the lowest level applicable to the terminal. If the MCS level is adjusted to the lowest level applicable to the terminal and the response of the power control request message is retransmitted and the response is not received or the response includes unrecognized information, the power control setting of the terminal is treated as a failure. Power control method of the terminal, characterized in that. The method of claim 10, wherein in the second step Checking the number of retransmissions of the power control request message, and determining the retransmission of the power control request message if the number of retransmissions does not exceed a preset maximum number of retransmissions. delete In the base station for providing a wireless communication service to the terminal, A message checking unit for checking a response of the power control request message transmitted from the terminal; A timer for generating time information serving as a criterion for determining whether a response from the terminal is received during a preset response waiting time; A retransmission information generation unit for generating retransmission information of the power control response message when the response from the terminal is not received during a preset response waiting time by using the time information from the timer; A retransmission control unit configured to generate a retransmission count information of the power control response message by counting the number of transmissions of the power control response message; An MCS level setting unit for setting an MCS level applied to the terminal according to a channel state between the terminal and the base station and retransmission information of the power control response message; And A scheduler constituting a frame transmitted to the terminal; The MCS level setting unit down-regulates the MCS level applied at the time of retransmission to be lower than the MCS level applied at the time of first transmission based on the retransmission number information. If the power control response message is retransmitted more than once, the MCS level applied during retransmission is adjusted to the lowest level applicable to the terminal. The retransmission control unit adjusts the MCS level to the lowest level applicable to the terminal and retransmits the power control request message. When the response from the terminal is not received during a preset response waiting time, the power control setting of the terminal is performed. Characterized in that the processing as a failure. delete delete The method of claim 13, wherein the retransmission information generating unit And generating retransmission information when the number of retransmissions of the current power control response message to be retransmitted does not exceed a preset maximum retransmission number. delete The method of claim 13, wherein the MCS level setting unit If the retransmission of the power control response message is the first, the base station, characterized in that the MCS level is set to a lower level of the MCS level and the reference MCS level determined according to the channel state of the terminal.

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