TWI434589B - Apparatus and method for controlling uplink transmission power in a mobile communication system - Google Patents

Description

Device and method for controlling uplink transmission power in mobile communication system

The present invention relates to an apparatus and method for controlling uplink transmission power in a mobile communication system. More specifically, the present invention relates to controlling the uplink transmission power by compensating for the difference between the downlink path loss and the uplink path loss in the mobile communication system.

In order to increase system capacity and improve service quality, the mobile communication system adopts downlink and uplink transmission power control schemes. However, the uplink transmission power control scheme of the current mobile communication system is designed without considering the difference between the downlink path loss and the uplink path loss. This situation means that the conventional uplink transmission power control scheme is based on the fact that the downlink path loss is the same as the uplink path loss.

A mobile communication system such as a Frequency Division Duplexing (FDD) communication system can operate in different operating bands, or in a region managed by a repeater, the downlink gain may be different from the upstream gain. The FDD communication system can be, for example, an Orthogonal Frequency Division Multiple Access (OFDMA) based Institute of Electrical and Electronics Engineers (IEEE) 802.16m communication system.

Although there are different downlink path losses and the possibility of uplink path loss under different operating frequency bands or under different conditions of downlink gain and uplink gain, the conventional uplink transmission power control scheme is based on the downlink path loss being equal to the uplink path. Designed with the assumption of loss. Therefore, if under The uplink path power loss is not effective when the line path loss is different from the uplink path loss.

Aspects of the present invention will address at least the above mentioned problems and/or disadvantages and at least the advantages described below. Accordingly, aspects of the present invention will provide an apparatus and method for controlling uplink transmission power in a mobile communication system.

Another aspect of the present invention is to provide an apparatus and method for controlling uplink transmission power by compensating for a difference between a downlink path loss and an uplink path loss in a mobile communication system.

According to an aspect of the present invention, a method of controlling uplink transmission power at an Advanced Mobile Station (AMS) in a mobile communication system is provided. The method includes determining uplink transmission power based on: measured path loss, uplink noise and interference level received from an advanced base station (ABS), target signal to noise, and interference Signal-to-Noise and Interference Ratio (SINR), and offset. The initial value of the offset is determined based on each of: the number of retransmissions of the initial ranging code performed before the initial ranging procedure is completed, and the transmission power unit for retransmission of the initial ranging code And a power correction value received from the ABS when the initial ranging procedure is completed by the ABS.

According to another aspect of the present invention, a method of supporting uplink transmission power control of an AMS at an ABS in a mobile communication system is provided. The method includes: powering a power when the initial ranging procedure is completed by the AMS A positive value is transmitted to the AMS, and a Ranging Request (RNG-REQ) message is received, the RNG-REQ message including an initial value for the AMS to determine an offset of the uplink transmission power. The initial value of the offset is determined based on each of: a number of retransmissions of an initial ranging code performed before completing the initial ranging procedure, and a retransmission for the initial ranging code The transmission power unit, and the power correction value received from the ABS when the initial ranging procedure is completed by the ABS.

According to another aspect of the present invention, an AMS in a mobile communication system is provided. The AMS includes a controller for determining uplink transmit power using the measured path loss, uplink and interference levels received from the ABS, target SINR, and offset. The initial value of the offset is determined based on each of: the number of retransmissions of the initial ranging code performed before the initial ranging procedure is completed, and the transmission power unit for retransmission of the initial ranging code And a power correction value received from the ABS when the initial ranging procedure is completed by the ABS.

According to another aspect of the present invention, an ABS for use in a mobile communication system is provided. The ABS includes: a transmitter for transmitting a power correction value to an AMS when an initial ranging procedure is completed by the AMS; and a receiver for receiving an RNG-REQ message, The RNG-REQ message contains an initial value for the AMS to determine the offset of the uplink transmission power. The initial value of the offset is determined based on each of: a number of retransmissions of an initial ranging code performed before completing the initial ranging procedure, and a retransmission for the initial ranging code The transmitted transmission power unit and the power correction value received from the ABS when the initial ranging procedure is completed by the ABS.

Other aspects, advantages, and features of the invention will be apparent from the description of the appended claims.

The above and other aspects, features, and advantages of the present invention will become more apparent from the following description of the appended claims.

Throughout the drawings, the same reference numerals are used to refer to the

The following description of the invention is intended to be understood as The description below contains various specific details that are helpful to the understanding, but such specific details are only to be considered as illustrative. Therefore, it will be appreciated by those skilled in the art that various changes and modifications of the embodiments described herein can be made without departing from the scope and spirit of the invention. In addition, descriptions of well-known functions and constructions may be omitted for clarity and conciseness.

The use of the terms and words in the following description and claims is not to be construed as a Therefore, it should be apparent to those skilled in the art that the following description of the exemplary embodiments of the present invention are intended to be illustrative only and not intended to limit the invention (e.g. The purpose of the equivalent definition).

It is to be understood that the singular and Thus, for example, reference to "a component surface" includes reference to one or more of such surfaces.

An exemplary embodiment of the present invention provides an apparatus and method for controlling uplink transmission power in a mobile communication system. Exemplary embodiments of the present invention also provide an apparatus and method for controlling uplink transmission power by compensating for a difference between a downlink path loss and an uplink path loss in a mobile communication system.

The following description is based on the assumption that the Orthogonal Frequency Division Multiple Access (OFDMA) based Institute of Electrical and Electronics Engineers (IEEE) 802.16m communication system is used as an example of a mobile communication system. The apparatus and method for controlling uplink transmission power according to an exemplary embodiment of the present invention are applicable to other mobile communication systems and IEEE 802.16m communication systems. Moreover, an apparatus and method for controlling uplink transmission power according to an exemplary embodiment of the present invention can be used in a mobile communication system that experiences different downlink path loss and uplink path loss.

The uplink transmission power control scheme used in the current IEEE 802.16m communication system is expressed as: P [dBm] = L + SINR _{T arg et} + NI + Offset .....(1)

Where P means the uplink transmission power, L means the path loss under the measurement by the Advanced Mobile Station (AMS), and SINR _{T arg et} means the target signal-to-interference and noise ratio of the signal received by the Advanced Base Station (ABS). (SINR), NI means the upstream noise and interference level measured by ABS, and Offset means the power offset. Uplink noise and interference level NI are broadcast by ABS.

SINR _{T arg et} is determined differently depending on the AMS transmission data signal or control signal. The ABS determines the target SINR ( SINR _{T arg et} ) of each control signal and broadcasts the target SINR ( SINR _{T arg et} ). In addition, the ABS determines the target SINR ( SINR _{T arg et} ) of the data signal according to equation (2), and transmits the target SINR ( SINR _{T arg et} ) to the AMS.

Wherein SINR _MIN means the SINR corresponding to the minimum data rate of the AMS set and broadcast by the ABS, and γIoT means the control factor for controlling the interference over thermal noise (IoT), SIR _DL means The signal-to-interference ratio (SIR) measured by AMS, α means the control factor determined by considering the number of antennas used by the ABS, and β means that when the ABS receives from the AMS The data signal in the form of multiple streams is used for the control factor of power normalization, and TNS (Total Number of Streams; TNS) means the total number of streams. If the IEEE 802.16m communication system uses a Single User Multiple Input Multiple Output (SU-MIMO) scheme, TNS means the total number of streams received from the AMS. If the IEEE 802.16m communication system uses a Multi-User Multiple Input Multiple Output (MU-MIMO) scheme, TNS means the total number of streams received from multiple AMSs.

In equation (1), the Offset can be classified into Offset _Data or Offset _Control depending on whether the AMS transmits a data signal or a control signal. When _{the Data} Offset Offset represents the AMS when transferring data signals, and Offset Offset _Control indicates when the transmission control signal when the AMS. Offset _Data and Offset _Control can be updated by signaling in the form of a message. If the AMS is currently storing a represents the current Offset _Data and Offset _Control of Offset _Data _C and Offset _Control _C, then from the ABS is received Offset _Data _new and Offset _Control _new, AMS updates to Offset _Data _new Offset _Data _C and Offset _Control _C And Offset _Control _new .

The uplink transmission power control scheme as described in equation (1) is designed based on the fact that the downlink path loss is equal to the uplink path loss. Thus, the use of an uplink transmission power control scheme as described in equation (1) can result in degradation of uplink transmission power control performance in environments that experience different downlink path losses and uplink path losses, such as in IEEE 802.16m communication systems.

Accordingly, an exemplary embodiment of the present invention provides a method of controlling uplink transmission power by compensating for a difference between a downlink power loss and an uplink power loss. The uplink transmission power control method according to an exemplary embodiment of the present invention includes an initial ranging procedure - an uplink transmission power control method, a periodic ranging procedure - an uplink transmission power control method, and a bandwidth request (Band Width Request; BW REQ) Preamble code transmission procedure - uplink transmission power control method.

First, a description will be given regarding the initial ranging procedure - the uplink transmission power control method.

According to the initial ranging procedure-uplink transmission power control method, the AMS determines the initial value of the Offset described in Equation (1) to compensate for the difference between the downlink path loss and the uplink path loss after completing the initial ranging procedure. Control its uplink transmission power. This operation is described below.

The uplink transmission power control scheme described in equation (1) is for the AMS that has completed the initial ranging procedure, that is, the AMS in the connected mode. Therefore, before the AMS completes the initial ranging procedure by the ABS, the AMS operates according to the uplink transmission power control scheme as described in equation (3).

PTX_IR_MIN = EIRxPIR, min + BS_EIRP-RSS +( GRx_MS-GTx_MS ).....(3)

Where PTX_IR_MIN means the transmission power when the AMS transmits the initial ranging code to the ABS, EIRxPIR,min means the target received power when the ABS wants to receive the signal, BS_EIRP means the total downlink transmission power of the ABS, and RSS means the measurement by the AMS Received Signal Strength (RSS), GRx_MS means the receive gain of the AMS, and GTx_MS means the transmit gain of the AMS. The ABS determines the target received power EIRxPIR,min and broadcasts the target received power EIRxPIR,min .

The AMS performs the initial ranging procedure by the ABS using the uplink transmission power PTX_IR_MIN determined by Equation (3). The AMS transmits the initial ranging code to the ABS with the transmission power PTX_IR_MIN , and receives a response signal for the transmitted initial ranging code from the ABS, thereby completing the initial ranging procedure.

However, if the AMS fails to receive the response signal for the transmitted initial ranging code from the ABS within a predetermined time, the AMS increases the transmission power obtained by adding a predetermined power unit from the transmission power PTX_IR_MIN to initial the ranging. The code is retransmitted to the ABS. The AMS can retransmit the initial ranging code within a predetermined number of retransmissions.

Let P_InitialStep (dB) be the power unit used to retransmit the initial ranging code. Then, if the initial ranging code has been retransmitted for a total of N times, that is, the power unit P_InitialStep (dB) has been used for a total of N times, the AMS determines the initial value of the Offset described in Equation (1) according to the following equation. .

Offset _Data = N × P_InitialStep + Delta_InitialBS Offset _Control = N × P_InitialStep + Delta_InitialBS .....(4)

Where Delta_InitialBS means the power correction value set in the response signal for the initial ranging code transmitted by the ABS, that is, the power correction value [dB] of the ABS decision. For example, when the ABS determines that it is necessary to adjust the received power of the initial ranging code received from the AMS, the ABS transmits the power correction value Delta_InitialBS to the AMS in the response signal for the initial ranging code.

If the ABS determines that it is not necessary to adjust the received power of the initial ranging code, the ABS may not include the power correction value Delta_InitialBS in the response signal for the initial ranging code.

The ABS may transmit the power correction value Delta_InitialBS to the AMS multiple times (eg, M times) before the initial ranging procedure is successful. Based on the assumption that the power correction value Delta_InitialBS has been transmitted for M times, the AMS can determine the initial value of Offset by Equation (5) (considering the power correction value Delta_InitialBS transmitted for M times).

Offset _Data = N × P_InitialStep +Σ Delta_InitialBS ( m ) Offset _Control = N × P_InitialStep +Σ Delta_InitialBS ( m ).....(5)

Where Delta_InitialBS ( m ) means the power correction value Delta_InitialBS of the mth transmission, where m=1, . . . , M.

The target received power EIRxPIR,min of the received signal (i.e., the initial ranging signal) in equation (3) may be different from the sum of the two: the target SINR of the actual initial ranging channel ( SINR _{T arg et} ), and Upstream noise and interference level NI . To compensate for the difference may be determined by the formula of the initial value _{Offset: Offset Data = PTX_IR_Final - (L} + SINR T arg et + NI) - 10log 10 (NumSubcarrierRNG) Offset Control = PTX_IR_Final - (L + SINR T arg et + NI )- 10log 10 ( NumSubcarrierRNG )+ P _{CDMA_allocation} .....(6)

Where PTX_IR_Final can be given as follows: PTX_IR_Final = PTX_IR_MIN + N × P_InitialStep +Σ Delta_InitialBS ( m ).....(7)

In equation (6), SINR _{T arg et} means the target SINR of the signal received at the ABS. A specific channel can be designated as a reference signal. In this case, SINR _{T arg et} represents the SINR value required for the required error rate for that particular channel. For example, if the non-synchronous ranging channel is set as the reference channel, the SINR _{T arg et} should be set to the target SINR ( SINR _{Non-syncRanging} ) of the asynchronous ranging channel.

In equation (6), NumSubcarrierRNG means the total number of subcarriers included in the bandwidth for initial ranging. P _{CDMA_allocation} means the uplink power correction value set by the uplink resource allocation signaling from the ABS (for example, the "off control Offcontrol" field of the CDMA allocation information element (IE) transmitted by the ABS. Included in it).

Although the initial value of Offset is calculated using the uplink power correction value P _{CDMA_allocation with reference} to Equation (6), the initial value of Offset (ignoring the uplink power correction value P _{CDMA_allocation} ) may also be determined in Equation (6). The uplink transmission power control scheme of equation (1) can be expressed as follows: P [dBm] = L + SINR _{T arg et} + NI + Offset_initial_default + OffsetMS .....(8)

Based Offset_initial_default + OffsetMS equal to Equation (1) Offset of assumption OffsetMS may be given as in Equation (9). That is, the Offset_initial_default is set to a preset value (for example, "0" in the initial ranging procedure used in the current IEEE 802.16m communication system), and the OffsetMS is used to determine the initial value of the Offset of the equation (1). .

OffsetMS = N × P_InitialSte p + Delta_InitialBS .....(9)

Although the AMS may determine OffsetMS based on N×P_InitialSte p after N retransmission of the initial ranging code, the AMS may be retransmitted every time the initial ranging code (ie, at every ramping up) use P_InitialSte p OffsetMS updated as shown in equation (10) described, and each time it receives the Delta_InitialBS, the AMS may additionally Delta_InitialBS reflected in the update, as in equation (11) as described.

OffsetMS = OffsetMS_c + P_InitialSt ep .....(10)

OffsetMS = OffsetMS_c + Delta_InitialBS .....(11)

Where OffsetMS_c means the current value of OffsetMS .

A description will now be given of a periodic ranging procedure - an uplink transmission power control method.

According to the periodic ranging procedure-uplink transmission power control method, the AMS updates the Offset described in Equation (1) to control the difference between the downlink path loss and the uplink path loss after completing the periodic ranging procedure. Its uplink transmission power. This operation is described below. The periodic ranging procedure is also called "synchronous ranging".

The periodic ranging procedure is a procedure for transmitting a periodic ranging code to an ABS according to a predetermined condition by an AMS in a connected mode and controlling the transmission power, offset offset, and time offset of the AMS by the ABS. The AMS transmits the periodic ranging code to the ABS with the uplink transmission power P determined by Equation (1), and receives the response signal for the transmitted periodic ranging code from the ABS, thereby completing the periodic ranging procedure. .

However, if the AMS fails to receive the response signal for the transmitted periodic ranging code from the ABS within the predetermined time, the AMS will periodically increase the transmission power by increasing the transmission power from the transmission power P by a predetermined power unit. The code is retransmitted to the ABS. The AMS may retransmit the periodic ranging code within a predetermined number of retransmissions.

Let P_PeriodicStep (dB) be the power unit used to retransmit the periodic ranging code. Then, if the periodic ranging code has been retransmitted for a total of N times, that is, the power unit P_PeriodicStep (dB) has been used for a total of N times, the AMS determines the initial of the Offset described in Equation (1) according to the following equation: value.

Offset _Data = Offset _Data _c + N × P_PeriodicStep + DeltaPeriodicBS Offset _Control = Offset _Control _c + N × P_PeriodicStep + DeltaPeriodicBS .....(12)

Wherein the means to Offset _Data _c Offset _Data briefly before use AMS performs the periodic ranging procedure, and Offset _Control _c Offset _Control is meant to be used before the short AMS performs the periodic ranging procedure.

In Equation (12), DeltaPeriodicBS means the power correction value set in the response signal for the periodic ranging code transmitted by the ABS, that is, the power correction value [dB] of the ABS decision. For example, when the ABS determines that it is necessary to adjust the received power of the periodic ranging code received from the AMS, the ABS transmits the power correction value D taPeriodicBS to the AMS in the response signal for the periodic ranging code.

If the ABS determines that it is not necessary to adjust the received power of the periodic ranging code, the ABS may not include the power correction value DeltaPeriodicBS in the response signal for the periodic ranging code.

The uplink transmission power control scheme of equation (1) can be expressed as follows: P [dBm] = L + SINR _{T arg et} + NI + Offset_periodic_default + OffsetMS .....(13)

Based Offset_periodic_default + OffsetMS equals equation (1) Offset of assumptions can be as in equation (14) gives OffsetMS. Offset_periodic_default is the Offset that the AMS briefly uses before the periodic ranging procedure, and the AMS uses OffsetMS to update the Offset of Equation (1).

OffsetMS = OffsetMS_c + N × P_PeriodicStep + DeltaPeriodicBS .....(14)

Although the AMS can determine OffsetMS based on N × P_PeriodicSt ep after retransmission of the periodic ranging code N times, the AMS can use P_PeriodicSt every time the periodic ranging code is retransmitted (that is, every ramp up) . ep updated OffsetMS, as shown in equation (15) as described. Or each time the DeltaPeriodicBS is received from the ABS, the AMS can update the OffsetMS using the DeltaPeriodicBS as described in equation (16).

OffsetMS = OffsetMS_c + P_PeriodicStep .....(15)

OffsetMS = OffsetMS_c + DeltaPeriodicBS .....(16)

Where OffsetMS_c means the current value of OffsetMS .

Finally, a description will be given of the BW REQ preamble transmission procedure - the uplink transmission power control method.

According to the BW REQ preamble transmission procedure - uplink transmission power control method, the AMS updates the Offset described in equation (1) to compensate for the difference between the downlink path loss and the uplink path loss after completing the BW REQ preamble transmission procedure. The difference is to control its uplink transmission power. This operation is described below.

During the BW REQ preamble transmission procedure, the AMS transmits the BW REQ preamble to the ABS with the uplink transmission power P determined by equation (1), and receives the transmitted BW REQ preamble from the ABS. The response signal completes the BW REQ preamble transmission procedure.

However, if the AMS fails to receive the response signal for the transmitted BW REQ preamble from the ABS within the predetermined time, the AMS pre-positions the BW REQ by increasing the transmission power from the transmission power P by a predetermined power unit. The code is retransmitted to the ABS. The AMS can retransmit the BW REQ preamble within a predetermined number of retransmissions.

Let P_BWREQStep (dB) be the power unit used to retransmit the BW REQ preamble. Thus, if the BW REQ preamble has been retransmitted for a total of N times, that is, the power unit P_BWREQStep (dB) has been used for a total of N times, the AMS determines the initial of the Offset described in Equation (1) according to the following equation. value.

Offset _Data = Offset _Data _c + N × P_BWREQStep + DeltaBWREQBS Offset _Control = Offset _Control _c + N × P_BWREQStep + DeltaBWREQBS .....(17)

Wherein briefly before use to AMS Offset _Data _c means performing the preamble transmission procedure BW REQ Offset _Data, and Offset _Control _c Offset _Control is meant to be used before the short AMS performed BW REQ preamble transmission procedure.

In Equation (17), DeltaBWREQ BS means the power correction value set in the response signal for the BW REQ preamble transmitted by the ABS, that is, the power correction value [dB] of the ABS decision. For example, when the ABS determines that it is necessary to adjust the received power of the BW REQ preamble received from the AMS, the ABS transmits the power correction value DeltaBWREQ BS to the AMS in the response signal for the BW REQ preamble.

If the ABS determines that it is not necessary to adjust the received power of the BW REQ preamble, the ABS may not include the power correction value DeltaBWREQ BS in the response signal for the BW REQ preamble.

The uplink transmission power control scheme of equation (1) can be expressed as follows: P [dBm] = L + SINR _{T arg et} + NI + Offset_BWREQ_default + OffsetMS .....(18)

Based Offset_BWREQ_default + OffsetMS equal to Equation (1) Offset of assumption may be given as OffsetMS equation (19). Offset_BWREQ_default is the Offset that AMS briefly uses before the BW REQ preamble transmission procedure, and the AMS uses OffsetMS to update the Offset of Equation (1).

OffsetMS = OffsetMS_c + N × P_BWREQStep + DeltaBWREQ BS .....(19)

Although the AMS can determine OffsetMS based on N × P_BWREQStep after N retransmission of the BW REQ preamble, the AMS can use P_BWREQStep every time the BW REQ preamble retransmission (ie, every time the ramp rises) Update OffsetMS as described in equation (20). Or each time a DeltaBWREQ BS is received from the ABS, the AMS may use the DeltaBWREQ BS to determine OffsetMS as described in equation (21).

OffsetMS = OffsetMS_c + P_BWREQStep .....(20)

OffsetMS = OffsetMS_c + DeltaBWREQ BS .....(21)

Where OffsetMS_c means the current value of OffsetMS .

The above description has been given regarding the procedure in which the AMS determines the initial value of Offset in the initial ranging procedure uplink transmission power control method, and the uplink transmission power control method and the BW REQ preamble transmission procedure in the periodic ranging procedure. The offset value is updated in the uplink transmission power control method. The AMS shall report the initial value of its determined Offset and the updated offset value to the ABS. How the AMS reports the initial value of its determined Offset and the updated offset value to the ABS will be described below.

An initial ranging procedure-uplink transmission power control operation of an ABS in an IEEE 802.16m communication system according to an exemplary embodiment of the present invention will be described below with reference to FIG.

1 is a flow chart illustrating an initial ranging procedure of an ABS-uplink transmission power control operation in an IEEE 802.16m communication system according to an exemplary embodiment of the present invention.

Referring to Figure 1, in step 111, the ABS broadcasts parameters for use in the uplink transmission power control scheme. Upon detecting the initial ranging code received from the AMS (step 113), the ABS determines the power correction value Delta_InitialBS based on the received power of the detected initial ranging code (step 115), and determines the power. The correction value Delta_InitialBS is transmitted to the AMS (step 117). In step 119, the ABS receives a report on the initial value of Offset from the AMS.

An initial ranging procedure-uplink transmission power control operation of the AMS in the IEEE 802.16m communication system according to an exemplary embodiment of the present invention will be described below with reference to FIG.

2 is a diagram showing an initial ranging procedure of an AMS in an IEEE 802.16m communication system according to an exemplary embodiment of the present invention - uplink transmission work Flow chart of rate control operations.

Referring to FIG. 2, the AMS receives the parameters for use in the uplink transmission power control scheme from the ABS broadcast (step 211), and determines the uplink transmission power PTX_IR_MIN by which the initial ranging code is transmitted (step 213). In step 215, the AMS transmits the initial ranging code in the upper ranging transmission power PTX_IR_MIN in the initial ranging opportunity. In step 217, the AMS determines whether a response signal for the transmitted initial ranging code has been received from the ABS within a predetermined time. If the response signal for the transmitted initial ranging code is not received from the ABS within a predetermined time, the AMS adds the transmission power PTX_IR_MIN to a transmission power unit P_InitialStep for the initial ranging procedure (step 219), and The increased transmission power PTX_IR_MIN is used to retransmit the initial ranging code (step 215).

When the response signal for the transmitted initial ranging code is received from the ABS within the predetermined time (step 217), the AMS determines whether the power correction value Delta_InitialBS is included in the response signal (step 221). If the power correction value Delta_InitialBS is included in the response signal, then in step 223, the AMS stores the number N of retransmissions of the initial ranging code, the transmission power unit P_InitialStep, and the power correction value Delta_InitialBS . In step 225, the AMS determines if the response signal for the transmitted initial ranging code indicates success. If the response signal indicates success, the AMS proceeds to step 227. On the other hand, if the response signal does not indicate success, the AMS returns to step 215.

If the power correction value Delta_InitialBS is not included in the response signal (step 221), the AMS jumps to step 227.

In step 227, the AMS receives the uplink power correction value P _{CDMA_allocation} from the ABS. The AMS determines an initial value of Offset in one of the methods as described in equations (4), (5), and (6) (step 229), and reports the determined initial value of Offset to the ABS (step 231). .

The periodic ranging procedure-uplink transmission power control operation of the ABS in the IEEE 802.16m communication system according to an exemplary embodiment of the present invention will be described below with reference to FIG.

3 is a flow chart illustrating a periodic ranging procedure-uplink transmission power control operation of an ABS in an IEEE 802.16m communication system according to an exemplary embodiment of the present invention.

Referring to Figure 3, in step 311, the ABS broadcasts parameters for use in the uplink transmission power control scheme. Upon detecting the periodic ranging code received from the AMS (step 313), the ABS determines the power correction value DeltaPeriodicBS based on the received power of the detected periodic ranging code (step 315), and determines The power correction value DeltaPeriodicBS is transmitted to the AMS (step 317). In step 319, the ABS receives a report on the updated value of Offset from the AMS.

A description will be made below of a periodic ranging procedure-uplink transmission power control operation of an AMS in an IEEE 802.16m communication system according to an exemplary embodiment of the present invention with reference to FIG.

4 is a flow chart illustrating a periodic ranging procedure-uplink transmission power control operation of an AMS in an IEEE 802.16m communication system according to an exemplary embodiment of the present invention.

Referring to FIG. 4, the AMS receives the parameters for use in the uplink transmission power control scheme from the ABS broadcast (step 411), and determines the uplink transmission power P when the periodic ranging code is transmitted (step 413). In step 415, the AMS transmits the periodic ranging code by transmitting the power P above the periodic ranging opportunity. In step 417, the AMS determines whether a response signal for the transmitted periodic ranging code has been received from the ABS within a predetermined time. If the response signal for the transmitted periodic ranging code is not received from the ABS within the predetermined time, the AMS updates the transmission by increasing the transmission power P by a transmission power unit P_PeriodicStep for the periodic ranging procedure. Power P (step 419), and the periodic ranging code is retransmitted with the increased transmission power P (step 415).

When the response signal for the transmitted periodic ranging code is received from the ABS within the predetermined time (step 417), the AMS determines whether the power correction value DeltaPeriodic BS is included in the response signal (step 421). If the power correction value DeltaPeriodicBS is included in the response signal, then in step 423, the AMS updates the value of Offset using the number N of retransmissions of the periodic ranging code, the transmission power unit P_PeriodicStep, and the power correction value DeltaPeriodicBS . In step 427, the AMS determines whether the response signal for the transmitted periodic ranging code indicates success. If the response signal indicates success, the AMS proceeds to step 429. On the other hand, if the response signal does not indicate success, the AMS returns to step 415.

If the power correction value DeltaPeriodicBS is not included in the response signal (step 421), the AMS proceeds to step 425. In step 425, the AMS updates the value of Offset using the number N of retransmissions of the periodic ranging code and the transmission power unit P_PeriodicStep , and proceeds to step 429. In step 429, the AMS reports the updated value of the Offset to the ABS.

The BW REQ preamble transmission procedure-uplink transmission power control operation of the ABS in the IEEE 802.16m communication system according to an exemplary embodiment of the present invention will be described below with reference to FIG.

5 is a flow chart illustrating an AW BW REQ preamble transmission procedure - an uplink transmission power control operation in an IEEE 802.16m communication system according to an exemplary embodiment of the present invention.

Referring to Figure 5, in step 511, the ABS broadcasts parameters for use in the uplink transmission power control scheme. Upon detecting the BW REQ preamble received from the AMS (step 513), the ABS determines the power correction value DeltaBWREQ BS based on the received power of the detected BW REQ preamble (step 515), and The determined power correction value DeltaBWREQ BS is transmitted to the AMS (step 517). In step 519, the ABS receives a report on the updated value of Offset from the AMS.

The BW REQ preamble transmission procedure-uplink transmission power control operation of the AMS in the IEEE 802.16m communication system according to an exemplary embodiment of the present invention will be described below with reference to FIG.

6 is a flow chart illustrating an AW BW REQ preamble transmission procedure-uplink transmission power control operation in an IEEE 802.16m communication system according to an exemplary embodiment of the present invention.

Referring to Fig. 6, the AMS receives the parameters for use in the uplink transmission power control scheme from the ABS broadcast (step 611), and determines the uplink transmission power P by which the BW REQ preamble is transmitted (step 613). In step 615, the AMS transmits the BW REQ preamble in the above-mentioned line transmission power P in the BW REQ preamble transmission opportunity. In step 617, the AMS determines whether a response signal for the transmitted BW REQ preamble has been received from the ABS within a predetermined time. If the response signal for the transmitted BW REQ preamble is not received from the ABS within the predetermined time, the AMS increases the transmission power P by a transmission power unit P_BWREQStep for the BW REQ preamble transmission procedure (step 619). And retransmitting the BW REQ preamble with the increased transmission power P (step 615).

When the response signal for the transmitted BW REQ preamble is received from the ABS within the predetermined time (step 617), the AMS determines whether the power correction value DeltaBWREQ BS is included in the response signal (step 621). If the power correction value DeltaBWREQ BS is included in the response signal, then in step 623, the AMS updates the value of Offset using the number N of retransmissions of the BW REQ preamble, the transmission power unit P_BWREQStep, and the power correction value DeltaBWREQ BS . In step 627, the AMS determines if the response signal for the transmitted BW REQ preamble indicates success. If the response signal indicates success, the AMS proceeds to step 629. On the other hand, if the response signal does not indicate success, that is, if the response signal indicates to continue, the AMS returns to step 615.

If the power correction value DeltaBWREQ BS is not included in the response signal (step 621), the AMS proceeds to step 625. In step 625, the AMS updates the value of Offset using the number N of retransmissions of the BW REQ preamble and the transmission power unit P_BWREQStep , and proceeds to step 629. In step 629, the AMS reports the updated value of the Offset to the ABS.

An exemplary embodiment in accordance with the present invention is described below with reference to FIG. Configuration of ABS in IEEE 802.16m communication system.

7 is a block diagram of an ABS in an IEEE 802.16m communication system in accordance with an exemplary embodiment of the present invention.

Referring to FIG. 7, the ABS includes a receiver 711, a controller 713, a transmitter 715, and a memory 717. The ABS may include other components that are not necessary for the implementation of the exemplary embodiments of the present invention and therefore are not described.

Controller 713 provides overall control of the ABS. The controller 713 controls all operations of the ABS with respect to the following: initial ranging procedure - uplink transmission power control method, periodic ranging procedure - uplink transmission power control method, and BW REQ preamble transmission procedure - uplink transmission power control method The method has been previously described and will therefore not be described again.

The controller 713 also controls transmission of parameters required for controlling uplink transmission power via the transmitter 715 in the following methods: an initial ranging procedure - an uplink transmission power control method, a periodic ranging procedure - an uplink transmission power control method, and BW REQ Preamble Transmission Procedure - Uplink Transmission Power Control Method, which has been previously described and will therefore not be described in detail.

The receiver 711 receives parameters required for controlling the uplink transmission power from the AMS in the following methods: an initial ranging procedure - an uplink transmission power control method, a periodic ranging procedure - an uplink transmission power control method, and a BW REQ preamble transmission Program-uplink transmission power control method, which has been previously described and will therefore not be described in detail. The memory 717 stores information required for the operation of the ABS.

Although the receiver 711, the controller 713, the transmitter 715, and the memory 717 are shown as separate units in FIG. 7, it should be clearly understood that the receiver 711, the controller 713, the transmitter 715, and the memory 717 can be combined. Into a single unit.

The configuration of the AMS in the IEEE 802.16m communication system according to an exemplary embodiment of the present invention is described below with reference to FIG.

8 is a block diagram of an AMS in an IEEE 802.16m communication system in accordance with an exemplary embodiment of the present invention.

Referring to FIG. 8, the AMS includes a receiver 811, a controller 813, a transmitter 815, and a memory 817. The AMS may also include other components that are not necessary for implementing the exemplary embodiments of the present invention and thus are not shown in FIG. 8 for clarity.

Controller 813 provides overall control of the AMS. The controller 813 controls all operations of the AMS regarding the following: initial ranging procedure - uplink transmission power control method, periodic ranging procedure - uplink transmission power control method, and BW REQ preamble transmission procedure - uplink transmission power control method The method has been previously described and will therefore not be described in detail.

In addition, the controller 813 controls transmission of parameters required for controlling uplink transmission power via the transmitter 815 in the following methods: an initial ranging procedure - an uplink transmission power control method, a periodic ranging procedure - an uplink transmission power control method, And a BW REQ preamble transmission procedure - an uplink transmission power control method, which has been previously described and thus will not be described in detail.

The receiver 811 receives parameters required for controlling the uplink transmission power from the ABS in the following methods: an initial ranging procedure - an uplink transmission power control method, a periodic ranging procedure - an uplink transmission power control method, and a BW REQ preamble Code Transmission Procedure - Uplink Transmission Power Control Method, which method has been previously described and will therefore not be described. The memory 817 stores information required for the operation of the AMS.

Although the receiver 811, the controller 813, the transmitter 815, and the memory 817 are shown as separate units in FIG. 8, it should be clearly understood that the receiver 811, the controller 813, the transmitter 815, and the memory 817 can be combined. Into a single unit.

After successfully performing the initial ranging procedure, the AMS determines the initial value of Offset as previously described, and transmits a ranging request (RNG-REQ) message in the uplink resource allocated by the CDMA Allocation A-MAP IE. . The AMS includes the initial value of the Offset in the RNG-REQ message so that the ABS can determine the difference between the uplink path loss and the downlink path loss calculated by the AMS, and the AMS reflecting the difference between the uplink path loss and the downlink path loss. The actual transmission power. Therefore, the ABS can accurately perform scheduling. According to an exemplary embodiment of the present invention, it is assumed that after the initial ranging procedure is successful, the AMS returns the initial value of Offset once in the RNG-REQ message. The initial value of the Offset can be included in the Offset _Initial field of the Upstream Power Control of the RNG-REQ message.

In Table 1, the initial offset of the upstream power control (Offset _Initial ) specifies a power level (eg, in 5 bits). The power level indicated by the initial offset of the uplink power control (Offset _Initial ) is determined by the AMS after a successful initial ranging procedure.

As is apparent from the above description of the exemplary embodiments of the present invention, the uplink transmission power can be controlled in the mobile communication system by compensating for the difference between the downlink path loss and the uplink path loss. Therefore, excessive transmission failure and excessive reception power can be prevented, thereby increasing the overall performance of the mobile communication system.

Although the present invention has been shown and described with respect to the specific embodiments of the present invention, it will be understood by those skilled in the art Various changes in form and detail are made in the present invention in the context of the invention.

711, 811‧‧‧ Receiver

713, 813‧‧ ‧ controller

715, 815‧‧ ‧ transmitter

717, 817‧‧‧ memory

1 is a flow chart illustrating an initial ranging procedure of an advanced base station (ABS) in an American Institute of Electrical and Electronics Engineers (IEEE) 802.16m communication system, an uplink transmission power control operation, in accordance with an exemplary embodiment of the present invention.

2 is a diagram illustrating an IEEE according to an exemplary embodiment of the present invention. The initial ranging procedure of the Advanced Mobile Station (AMS) in the 802.16m communication system - a flow chart of the uplink transmission power control operation.

3 is a flow chart illustrating a periodic ranging procedure-uplink transmission power control operation of an ABS in an IEEE 802.16m communication system according to an exemplary embodiment of the present invention.

4 is a flow chart illustrating a periodic ranging procedure-uplink transmission power control operation of an AMS in an IEEE 802.16m communication system according to an exemplary embodiment of the present invention.

5 is a flow chart illustrating an ABS bandwidth request (BW REQ) preamble transmission procedure-uplink transmission power control operation in an IEEE 802.16m communication system according to an exemplary embodiment of the present invention.

6 is a flow chart illustrating an AW BW REQ preamble transmission procedure-uplink transmission power control operation in an IEEE 802.16m communication system according to an exemplary embodiment of the present invention.

7 is a block diagram of an ABS in an IEEE 802.16m communication system in accordance with an exemplary embodiment of the present invention.

8 is a block diagram of an AMS in an IEEE 802.16m communication system in accordance with an exemplary embodiment of the present invention.

Step 211‧‧ AMS receives parameters from the ABS broadcast for use in the uplink transmission power control scheme

Step 213‧‧‧AMS determines the uplink transmission power PTX_IR_MIN

Step 215‧‧AMS transmits the initial ranging code in the initial ranging opportunity by transmitting the power PTX_IR_MIN

Step 217‧‧AMS determines whether a response signal for the transmitted initial ranging code has been received from the ABS within a predetermined time

Step 219‧‧‧AMS updates the uplink transmission power PTX_IR_MIN

Step 221.‧AMS determines whether the power correction value Delta_InitialBS is included in the response signal

Step 223‧‧AMS stores the number N of retransmissions of the initial ranging code, the transmission power unit P_InitialStep, and the power correction value Delta_InitialBS

Step 225‧‧‧AMS determines if the response signal for the transmitted initial ranging code indicates success

Step 227‧‧‧AMS receives uplink power correction value from ABS P _{CDMA_allocation}

Step 229‧‧‧AMS determines the initial value of Offset

Step 231‧‧AMS reports the initial value of the determined Offset to ABS

Claims (12)

A method of controlling uplink transmission power at an advanced mobile station (AMS) in a mobile communication system, the method comprising: determining uplink transmission power based on: measured path loss, from an advanced base station (ABS) Received uplink noise and interference levels, target signal to noise and interference ratio (SINR), and offset, wherein the initial value of the offset is determined based on: before completing the initial ranging procedure a number of retransmissions of the initial ranging code performed, a transmission power unit for retransmission of the initial ranging code, and from the ABS when the initial ranging procedure is completed by the ABS Received power correction value. The method of claim 1, wherein the initial value of the offset is expressed as the following equation, Offset _Data = PTX_IR_Final - ( L + SINR _{T arg et} + NI ) - 10log 10 ( NumSubcarrierRNG ) Offset _Control = PTX_IR_Final - ( L + SINR _{T arg et} + NI ) - 10log 10 ( NumSubcarrierRNG ) wherein Offset _Data means an initial value of the offset of the data signal when the uplink transmission power is applied to the data signal, Offset _Control means The initial value of the offset of the control signal when the uplink transmission power is applied to the control signal, L means the path loss, SINR _{T arg et} means the target SINR, and NI means the uplink noise and Interference level, NumSubcarrierRNG means the total number of subcarriers included in the bandwidth used for initial ranging, and PTX_IR_Final is expressed as the following equation, PTX_IR_Final = PTX_IR_MIN + N × P_InitialStep + Σ Delta_InitialBS ( m ) where PTX_IR_MIN means The transmission power when the AMS transmits the initial ranging code to the ABS, where N means the number of retransmissions of the initial ranging code, P_InitialStep Refers to the transmission power unit used for retransmission of the initial ranging code, Delta_InitialBS means the power correction value received from the ABS when the initial ranging procedure is completed, and Delta_InitialBS ( m ) Refers to the power correction value Delta_InitialBS of the mth transmission. The method of claim 1, wherein the target SINR comprises a target SINR of a non-synchronized ranging channel. The method of claim 1, wherein the offset comprises a value that compensates for a difference between a downlink path loss and an uplink path loss. The method of claim 1, further comprising transmitting a ranging request (RNG-REQ) message including the initial value of the offset to the ABS. A method for supporting uplink transmission power control of an advanced mobile station (AMS) via an advanced base station (ABS) in a mobile communication system, the method comprising: performing an initial ranging procedure by the AMS via the ABS Transmitting a power correction value to the AMS; and receiving a ranging request (RNG-REQ) message via the ABS, the RNG-REQ message including an initial for determining, by the AMS, an offset of an uplink transmission power a value, wherein the initial value of the offset is determined based on each of: a number of retransmissions of an initial ranging code performed prior to completing the initial ranging procedure, for the initial ranging code Retransmitted transmission a power unit, and the power correction value received from the ABS when the initial ranging procedure is completed by the ABS. The method of claim 6, further comprising transmitting, by the ABS, uplink noise and interference levels, a target signal to noise and interference ratio (SINR), and the offset, wherein the uplink The transmission power is determined based on: measured path loss, the uplink noise and interference level, the target SINR, and the offset, and wherein the path loss is measured by the AMS Measurement. The method of claim 7, wherein the initial value of the offset is expressed as the following equation, Offset _Data = PTX_IR_Final - ( L + SINR _{T arg et} + NI ) - 10log 10 ( NumSubcarrierRNG ) Offset _Control = PTX_IR_Final - ( L + SINR _{T arg et} + NI ) - 10log 10 ( NumSubcarrierRNG ) wherein Offset _Data means an initial value of the offset of the data signal when the uplink transmission power is applied to the data signal, Offset _Control means The initial value of the offset of the control signal when the uplink transmission power is applied to the control signal, L means the path loss, SINR _{T arg et} means the target SINR, and NI means the uplink noise and Interference level, NumSubcarrierRNG means the total number of subcarriers included in the bandwidth used for initial ranging, and PTX_IR_Final is expressed as the following equation, PTX_IR_Final = PTX_IR_MIN + N × P_InitialStep + Σ Delta_InitialBS ( m ) where PTX_IR_MIN means The transmission power when the AMS transmits the initial ranging code to the ABS, where N means the number of retransmissions of the initial ranging code, P_InitialStep Refers to the transmission power unit used for retransmission of the initial ranging code, Delta_InitialBS means the power correction value received from the ABS when the initial ranging procedure is completed, and Delta_InitialBS ( m ) Refers to the power correction value Delta_InitialBS of the mth transmission. The method of claim 7, wherein the target SINR comprises a target SINR of a non-synchronized ranging channel. The method of claim 7, wherein the offset comprises a value that compensates for a difference between a downlink path loss and an uplink path loss. An advanced action station (AMS) for performing the method of any one of claims 1 to 5. An advanced base station (ABS) for performing the method of any one of claims 6 to 10.