JP5858667B2 - Apparatus and method for controlling uplink transmission power in a mobile communication system - Google Patents

Description

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

  The mobile communication system uses downlink and uplink transmission power control schemes to increase system capacity and improve service quality. However, the uplink transmission power control method of the current mobile communication system was designed without considering the difference between the downlink path loss and the uplink path loss. This is based on the assumption that the downlink path loss and the uplink path loss are the same.

  On the other hand, a mobile communication system such as a frequency division duplex (hereinafter referred to as “FDD”) communication system has a different operating frequency band or is in a region managed by a repeater. The downlink gain and the uplink gain may be different from each other. Examples of the FDD communication system include an IEEE (Institute of Electrical and Electronics Engineers) 802.16m communication system based on an Orthogonal Frequency Division Multiple Access (hereinafter referred to as “OFDMA”) system.

  Thus, the downlink path loss and the uplink path loss may be different when the operating frequency band is different or when the downlink gain and the uplink gain are different. However, the conventional uplink transmission power control scheme is designed on the assumption that the downlink path loss is the same as the uplink path loss. Therefore, if the downlink path loss is different from the uplink path loss, the uplink transmission power control is not efficient.

US Patent Application Publication No. 2007 / 0149238A1 US Patent Application Publication No. 2009 / 0325627A1 US Patent Application Publication No. 2011 / 0141926A1

  Accordingly, the present invention has been proposed to solve the above-described problems of the prior art, and an object thereof is to provide an apparatus and method for controlling uplink transmission power in a mobile communication system.

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

  To achieve the above object, according to an aspect of an embodiment of the present invention, a method for controlling uplink transmission power of an advanced mobile station (AMS) in a mobile communication system is provided. To do. The above method is based on the measured path loss value, the uplink noise and interference level received from the advanced base station (ABS), the target signal to interference noise ratio (SINR), and the uplink transmission. Determining the power. The initial value of the offset includes the number of retransmissions of the initial ranging code performed until the initial ranging process is completed, the unit transmission power used for retransmission of the initial ranging code, and the advanced base station and initial ranging. It is determined based on the power adjustment value received from the advanced base station in completing the process.

  In accordance with another aspect of an embodiment of the present invention, a method is provided for an advanced base station (ABS) in a mobile communication system to support advanced mobile terminal (AMS) uplink transmission power control. The method includes transmitting a power adjustment value to the advanced mobile terminal upon completing the initial ranging process with the advanced mobile terminal, and the advanced mobile terminal determines uplink transmission power. Receiving a ranging request (RNG-REQ) message including the initial value of the offset used for the advanced mobile terminal. The initial value of the offset is the number of retransmissions of the initial ranging code executed until the initial ranging process is completed, the unit transmission power used for the retransmission of the initial ranging code, and the initial value of the advanced base station. It is determined based on the power adjustment value received from the advanced base station upon completion of the ranging process.

  According to yet another aspect of embodiments of the present invention, an advanced mobile terminal (AMS) in a mobile communication system is provided. The advanced mobile terminal uses the measured path loss value, the uplink noise and interference level received from the advanced base station (ABS), the target signal to interference noise ratio (SINR), and the uplink using the offset. A controller for determining transmission power is included. The initial value of the offset includes the number of retransmissions of the initial ranging code performed until the initial ranging process is completed, the unit transmission power used for retransmission of the initial ranging code, and the advanced base station and initial ranging. It is determined based on the power adjustment value received from the advanced base station in completing the process.

  According to yet another aspect of an embodiment of the present invention, an advanced base station (ABS) in a mobile communication system is provided. When the advanced base station completes the initial ranging process with the advanced mobile terminal, the transmitter transmits a power adjustment value to the advanced mobile terminal, and the advanced mobile terminal transmits an uplink. And a receiver that receives a ranging request (RNG-REQ) message including an initial value of an offset used to determine power from the advanced mobile terminal. The initial value of the offset is the number of retransmissions of the initial ranging code executed until the initial ranging process is completed, the unit transmission power used for the retransmission of the initial ranging code, and the initial value of the advanced base station. When the ranging process is complete, it is determined based on the power adjustment value received from the advanced base station.

  According to the embodiment of the present invention, the uplink transmission power can be controlled by compensating for the difference between the downlink path loss and the uplink path loss in the mobile communication system. Therefore, it is possible to prevent excessive transmission failure and excessive reception power, thereby improving the overall performance of the mobile communication system.

3 is a flowchart illustrating an initial ranging process uplink transmission power control operation of an ABS in an IEEE 802.16m communication system according to an embodiment of the present invention; 3 is a flowchart illustrating an initial ranging process uplink transmission power control operation of AMS in an IEEE 802.16m communication system according to an embodiment of the present invention; 3 is a flowchart illustrating an ABS periodic ranging process uplink transmission power control operation in an IEEE 802.16m communication system according to an embodiment of the present invention; 3 is a flowchart illustrating an AMS periodic ranging process uplink transmission power control operation in an IEEE 802.16m communication system according to an embodiment of the present invention; 6 is a flowchart illustrating an ABS bandwidth request preamble code transmission process uplink transmission power control operation in an IEEE 802.16m communication system according to an embodiment of the present invention; 5 is a flowchart illustrating an AMS bandwidth request preamble code transmission process uplink transmission power control operation in an IEEE 802.16m communication system according to an embodiment of the present invention; 1 is a block diagram illustrating a configuration of an ABS in an IEEE 802.16m communication system according to an embodiment of the present invention. 1 is a block diagram showing a configuration of an AMS in an IEEE 802.16m communication system according to an embodiment of the present invention.

  Other objects, advantages and salient features of the present invention will become apparent to those skilled in the art from the accompanying drawings and the following detailed description made from the embodiments of the present invention.

  The following description with reference to the accompanying drawings is provided to assist in a comprehensive understanding of the embodiments of the present invention as defined in the appended claims and their equivalents, It includes various specific details to aid in this understanding, but is only one embodiment. Accordingly, it will be apparent to those skilled in the art that various changes and modifications can be made to the embodiments described herein without departing from the scope and spirit of the invention. In addition, from the viewpoints of clarity and conciseness, detailed descriptions of functions and configurations well known to those skilled in the art are omitted.

  The terms and words used in the following description and claims are not limited to the dictionary meaning, but are used by the inventor to make the understanding of the present invention clear and consistent. Accordingly, it is to be defined based on the following claims and their equivalents, and the description of the embodiments of the present invention is merely provided for illustrative purposes and is intended to limit the purpose of the present invention. It will be clear to those of ordinary skill in the art of the present invention.

  Those skilled in the art will appreciate that each element described herein includes the plural unless the context clearly dictates otherwise. Thus, for example, reference to “a component surface” includes one or more surfaces.

  Embodiments of the present invention propose an apparatus and method for controlling uplink transmission power in a mobile communication system. Embodiments of the present invention also propose an apparatus and method for controlling uplink transmission power by compensating for a difference between downlink path loss and uplink path loss in a mobile communication system.

  In the present invention, an IEEE (Institute of Electrical and Electronics Engineers) 802.16m communication system based on an Orthogonal Frequency Division Multiplexing Access (hereinafter referred to as “OFDMA”) system is used as an example of a mobile communication system. Assume that The apparatus and method for controlling uplink transmission power according to embodiments of the present invention can be applied not only to the IEEE 802.16m communication system but also to other mobile communication systems. Also, the apparatus and method for controlling uplink transmission power according to embodiments of the present invention can be usefully used in a mobile communication system in which there is a difference between downlink path loss and uplink path loss.

First, the uplink transmission power control method used in the current IEEE 802.16m communication system is expressed as the following formula (1).
Formula (1)
P [dBm] = L + SINR _Target + NI + Offset
Here, P indicates uplink transmission power, L indicates downlink path loss measured by an advanced mobile station (hereinafter referred to as “AMS”), and SINR _Target indicates The target signal-to-interference and noise ratio (Signal-to-Interference and Noise Ratio: hereinafter referred to as “SINR”) of the signal received by the base station (Advanced Base Station: hereinafter referred to as “ABS”), NI indicates the uplink noise and interference level measured at the ABS, and Offset indicates the power offset. Uplink noise and interference level NI are values broadcast by the ABS.

The SINR _Target is determined in a different manner according to whether the signal transmitted by the AMS is a data signal or a control signal. That is, the ABS determines a SINR _Target that is a target SINR for each control signal, and broadcasts the determined SINR _Target . Further, the ABS determines the SINR _Target for the data signal as shown in the following formula (2), and transmits the SINR _Target to the corresponding AMS.
Formula (2)
SINR _Target = 10 · log 10 (max (10 ( ^SINR _MIN ^{[dB] / 10} , γ IoT · SIR _DL −α)) − β · 10 log 10 (TNS)
Here, SINR _MIN indicates SINR corresponding to the minimum transmission rate of AMS set and broadcast by ABS, γIoT indicates an adjustment factor used to adjust IoT (Interference over Thermal Noise) for the uplink, SIR _DL indicates a downlink signal-to-interference ratio (hereinafter referred to as “SIR”) measured by AMS, and α is an adjustment factor considering the number of antennas used by the ABS. Β denotes an adjustment factor for determining power normalization in the form of multi-stream when the ABS receives a data signal from the AMS, and TNS (Total Number of Streams) Indicates the number of total streams. When the IEEE 802.16m communication system uses a single user multiple input multiple output (SU-MIMO) scheme, the TNS indicates the total number of streams received from the corresponding AMS. When the IEEE 802.16m communication system uses a multi-user multiple input multiple output (MU-MIMO) scheme, the TNS indicates the total number of streams received from a plurality of AMSs.

In Equation (1), Offset is classified into Offset _Data and Offset _Control based on whether the signal transmitted by the AMS is a data signal or a control signal. Offset _Data indicates an Offset used when the AMS transmits a data signal, and Offset _Control indicates an Offset used when the AMS transmits a control signal. The Offset _Data and Offset _Control can be updated by signaling in the form of a message. That is, when the AMS is storing the _{Offset Data} _c and _{Offset Control} _c shows the current _{Offset Data} and _{Offset Control,} receives the _Offset Data _new and _{Offset Control} _new from ABS, AMS is, _{Offset Data} _c and _{Offset Control} Update _c to Offset _Data _new and Offset _Control _new.

  On the other hand, the uplink transmission power control method described as Equation (1) is designed on the assumption that there is no difference between the downlink path loss and the uplink path loss. Therefore, when the uplink transmission power control method described in Equation (1) is used as it is, an environment in which a difference between the downlink path loss and the uplink path loss may occur as in the IEEE 802.16m communication system. Then, there is a possibility that the performance of the uplink transmission power control will be reduced.

  Accordingly, embodiments of the present invention propose a scheme for controlling uplink transmission power by compensating for the difference between downlink path loss and uplink path loss. An uplink transmission power control scheme according to an embodiment of the present invention includes an initial ranging process uplink transmission power control scheme, a periodic ranging process uplink transmission power control scheme, and a bandwidth request (Bandwidth). Request: BW REQ) preamble code transmission process uplink transmission power control scheme.

First, the initial ranging process uplink transmission power control method will be described.
In accordance with the initial ranging process uplink transmission power control scheme, the AMS is configured to control its uplink transmission power by compensating for the difference between the downlink path loss and the uplink path loss after completing the initial ranging process. The initial value of Offset described in (1) is determined. This operation will be specifically described as follows.

The uplink transmission power control method as described in Equation (1) is an uplink transmission power control method used by an AMS that has completed the initial ranging process, that is, an AMS in a connected mode. Therefore, before the AMS completes the initial ranging process with the ABS, the AMS operates according to the uplink transmission power control scheme described as Equation (3).
Formula (3)
PTX_IR_MIN = EIRxPIR, min + BS_EIRP-RSS + (GRx_MS-GTx_MS)
Here, PTX_IR_MIN indicates the transmission power used when the AMS transmits the initial ranging code to the ABS, EIRxPIR, min indicates the target reception power of the received signal that the ABS desires to receive, and BS_EIRP is: ABS indicates the total downlink transmission power, RSS indicates the received signal strength (hereinafter referred to as “RSS”) measured by AMS, GRx_MS indicates the reception gain of AMS, and GTx_MS indicates The transmission gain of AMS is shown. The ABS determines the target received power EIRxPIR, min and broadcasts it.

  The AMS performs the initial ranging process with the ABS using the uplink transmission power determined by Equation (3), ie, PTX_IR_MIN. The AMS transmits the initial ranging code to the ABS using 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 process.

  However, if the AMS cannot receive a response signal for the transmitted initial ranging code from the ABS within a predetermined time, the AMS transmits the initial ranging code with a transmission power increased by a predetermined unit transmission power from the transmission power PTX_IR_MIN. Is retransmitted to the ABS. The AMS can retransmit this initial ranging code within a predetermined number of retransmissions.

When the unit transmission power used for retransmission of the initial ranging code is indicated by P_InitialStep (dB), when this initial ranging code is retransmitted a total of N times, that is, the unit transmission power P_InitialStep (dB) is total. When used N times, AMS determines the initial value of Offset described in Equation (1) according to Equation (4) below.
Formula (4)
Offset _Data = N × P_InitialStep + Delta_InitialBS
Offset _Control = N × P_InitialStep + Delta_InitialBS
Here, Delta_InitialBS indicates the power adjustment value set in the response signal for the initial ranging code transmitted by the ABS, that is, the power adjustment amount [dB] determined by the ABS. For example, when the ABS determines that the received power of the initial ranging code received from the AMS needs to be adjusted, the ABS includes the power adjustment value Delta_Initial BS in the response signal for the initial ranging code and transmits it to the AMS.

  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 adjustment value Delta_InitialBS in the response signal for the initial ranging code.

The ABS can send the power adjustment value Delta_Initial BS to the AMS multiple times, eg, M times, until the initial ranging process is successful. Under the assumption that the power adjustment value Delta_InitialBS has been transmitted M times, the AMS can determine the initial value of Offset according to the following equation (5) in consideration of the power adjustment value Delta_Initial BS transmitted M times.
Formula (5)
Offset _Data = N × P_InitialStep + ΣDelta_InitialBS (m)
Offset _Control = N × P_InitialStep + ΣDelta_InitialBS (m)
Here, Delta_InitialBS (m) indicates the power adjustment value Delta_InitialBS transmitted for the Mth time, where m = 1,. . . , M.
In Equation (3), the target received power of the received signal, that is, the target received power EIRxPIR, min of the initial ranging signal is the target SINR of the actual initial ranging channel, that is, SINR _Target , uplink noise, and interference level NI. It may be different from the total. Therefore, in order to compensate for this difference, the initial value of Offset can be determined as in the following formula (6).
Formula (6)
Offset _Data = PTX_IR_Final− (L + SINR _Target + NI) −10 log 10 (NumSubcarrierRNG)
Offset _Control = PTX_IR_Final− (L + SINR _Target + NI) −10 log 10 (NumSubcarrierRNG) + P _{CDMA_allocation}
Here, PTX_IR_Final can be expressed as the following formula (7).
Formula (7)
PTX_IR_Final = PTX_IR_MIN + N × P_InitialStep + ΣDelta_InitialBS (m)
In Equation (6), SINR _Target represents a target SINR of a signal received by the ABS. A particular channel can be designated as a reference channel. In this case, SINR _Target indicates the SINR value required for the required error rate for this particular channel. For example, when the non-synchronous ranging channel is set as the reference channel, the SINR _Target must be set to SINR _{Non-syncRanging} that is the target SINR of the asynchronous ranging channel.

In Equation (6), NumSubcarrierRNG indicates the total number of subcarriers included in the bandwidth used for initial ranging, and P _{CDMA_allocation} is set by uplink resource allocation signaling from the ABS. It shows an uplink power adjustment value included in the Offset control field of the CDMA allocation information element (IE) to be transmitted.

The initial value of Offset has been described with reference to Equation (6) calculated using the uplink power adjustment value P _{CDMA_allocation} . In Equation (6), the uplink power adjustment value P _{CDMA_allocation} is excluded, and the initial value of Offset is set. The value may be determined. The uplink transmission power control method of Equation (1) can be expressed by Equation (8) below.
Formula (8)
P [dBm] = L + SINR _Target + NI + Offset_initial_default + OffsetMS
Assuming that Offset_initial_default + OffsetMS is the same as Offset in Equation (1), OffsetMS can be expressed by Equation (9) below. That is, Offset_initial_default is set to a default value, eg, '0' in the initial ranging process, as used in the current IEEE 802.16m communication system, and the initial value of Offset in Equation (1) is set using OffsetMS. It is determined.
Formula (9)
OffsetMS = N × P_InitialStep + Delta_InitialBS
Although the AMS can determine the OffsetMS based on N × P_InitialStep after N retransmissions of the initial ranging code, as described in Equation (10) below, Each time a ramping up is performed, the OffsetMS is updated using P_InitialStep, and each time Delta_InitialBS is received from the ABS, AMS adds Delta_InitialBS to the update as described in Equation (11) below. Can also be reflected.
Formula (10)
OffsetMS = OffsetMS_c + P_InitialStep
Formula (11)
OffsetMS = OffsetMS_c + Delta_InitialBS
Here, OffsetMS_c indicates the current value of OffsetMS.

  Second, the periodic ranging process uplink transmission power control scheme will be described.

  In accordance with the periodic ranging process uplink transmit power control scheme, the AMS is configured to control its uplink transmit power by compensating for the difference between the downlink path loss and the uplink path loss after completing the periodic ranging process. The Offset described in Equation (1) is updated. This operation will be specifically described as follows. This periodic ranging process is also called 'synchronized ranging'.

  First, the periodic ranging process is a process in which the AMS in the connection mode transmits a periodic ranging code to the ABS according to a predetermined condition, and the ABS adjusts the transmission power, frequency offset, time offset, and the like of the AMS. The AMS transmits the periodic ranging code to the ABS using the uplink transmission power P determined by Equation (1), and receives a response signal for the transmitted periodic ranging code from the ABS. Complete the ranging process.

  However, if the AMS cannot receive a response signal for the transmitted periodic ranging code from the ABS within a predetermined time, the AMS uses the transmission power increased from the transmission power P by a predetermined unit transmission power. Retransmit this periodic ranging code to the ABS. The AMS can retransmit this periodic ranging code within a predetermined number of retransmissions.

The unit transmission power used for retransmission of this periodic ranging code is denoted by P_PeriodicStep [dB]. When this periodic ranging code is retransmitted a total of N times, that is, the unit transmission power P_PeriodicStep (dB). Is used N times in total, AMS determines the initial value of Offset described in Equation (1) according to Equation (12) below.
Formula (12)
_{Offset Data = Offset Data _c + N} × P_PeriodicStep + DeltaPeriodicBS
_{Offset Control = Offset Control _c + N} × P_PeriodicStep + DeltaPeriodicBS
Here, _{Offset Data} _c shows the _{Offset Data} to be used immediately before the AMS performs the periodic ranging _{process, Offset Control} _c shows _{Offset Control} to be used immediately before the AMS performs the periodic ranging process.

  In Equation (12), DeltaPeriodic BS indicates a power adjustment value set in a response signal to the periodic ranging code transmitted by the ABS, that is, a power adjustment amount [dB] determined by the ABS. For example, when the ABS determines that the received power of the periodic ranging code received from the AMS needs to be adjusted, the ABS includes the power adjustment value DeltaPeriodic BS in the response signal for the periodic ranging code and transmits it to the AMS. .

  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 adjustment value DeltaPeriodicBS in the response signal for the periodic ranging code.

The uplink transmission power control method of Equation (1) can be expressed by Equation (13) below.
Formula (13)
P [dBm] = L + SINR _Target + NI + Offset_periodic_default + OffsetMS
Assuming that Offset_periodic_default + OffsetMS in Equation (13) is the same as Offset in Equation (1), OffsetMS can be expressed by Equation (14) below. Offset_periodic_default is an offset that is used immediately before the AMS performs the periodic ranging process, and the AMS updates the offset of Equation (1) described above using the OffsetMS.
Formula (14)
OffsetMS = OffsetMS_c + N × P_PeriodicStep + DeltaPeriodicBS

The AMS may update the OffsetMS based on N × P_PeriodicStep after N retransmissions of the periodic ranging code, but this periodic ranging code retransmission may be performed as described in Equation 15 below. The OffsetMS may be updated using P_PeriodicStep every time, that is, every time ramping up is performed. Alternatively, each time a DeltaPeriodicBS is received from the ABS, the AMS may update the OffsetMS using the DeltaPeriodicBS as described in Equation (16) below.
Formula (15)
OffsetMS = OffsetMS_c + P_PeriodicStep
Formula (16)
OffsetMS = OffsetMS_c + DeltaPeriodicBS
Here, OffsetMS_c indicates the current value of OffsetMS.

  Finally, the bandwidth request preamble code transmission process uplink transmission power control scheme will be described.

  In accordance with this bandwidth request preamble code transmission process, the uplink transmission power control scheme allows the AMS to increase its uplink by compensating for the difference between the downlink path loss and the uplink path loss after completing the bandwidth request preamble code transmission process. The Offset described in the above equation (1) is updated so as to control the transmission power. This operation will be specifically described as follows.

  First, while performing the bandwidth request preamble code transmission process, the AMS transmits the bandwidth request preamble code to the ABS using the uplink transmission power P determined by Equation (1) described above, and this transmission. By receiving a response signal to the bandwidth request preamble code from the ABS, the bandwidth request preamble code transmission process is completed.

  However, when the AMS cannot receive a response signal for the transmitted bandwidth request preamble code from the ABS within a predetermined time, the AMS uses the transmission power increased from the transmission power P by a predetermined unit transmission power. The bandwidth request preamble code is retransmitted to the ABS. The AMS can also retransmit this bandwidth request preamble code within a predetermined number of retransmissions.

A unit transmission power used for retransmission of the bandwidth request preamble code is denoted by P_BWREQStep [dB]. When this bandwidth request preamble code is retransmitted a total of N times, that is, the unit transmission power P_BWREQStep is When used a total of N times, the AMS determines the initial value of Offset described in Equation (1) according to Equation (17) below.
Formula (17)
_{Offset Data = Offset Data _c + N} × P_BWREQStep + DeltaBWREQBS
Offset _Control = Offset _Control _c + N × P_BWREQStep + DeltaBWREQBS
Here, _{Offset Data} _c shows the _{Offset Data} to be used immediately before the AMS performs the bandwidth request preamble code transmission _{process, Offset Control} _c is used just before the AMS performs the bandwidth request preamble code transmission process The Offset _Control is shown.

  In the above equation (17), DeltaBWREQBS indicates the power adjustment value set in the response signal for the bandwidth request preamble code transmitted by the ABS, that is, the power adjustment amount [dB] determined by the ABS. For example, when the ABS determines that the received power of the bandwidth request preamble code received from the AMS needs to be adjusted, the ABS includes the power adjustment value DeltaBWREQBS in the response signal for the bandwidth request preamble code to the AMS. Send.

  When the ABS determines that it is not necessary to adjust the reception power of the bandwidth request preamble code, the ABS may not include the power adjustment value DeltaBWREQBS in the response signal for the bandwidth request preamble code.

The uplink transmission power control method of Equation (1) can be expressed by Equation (18) below.
Formula (18)
P [dBm] = L + SINR _Target + NI + Offset_BWREQ_default + OffsetMS
Assuming that Offset_BWREQ_default + OffsetMS in Equation (18) is the same as Offset in Equation (1), OffsetMS can be expressed by Equation (19) below. Offset_BWREQ_default is an offset used immediately before the AMS executes the bandwidth request preamble code transmission process, and the AMS updates the offset of Equation (1) described above using the OffsetMS.
Formula (19)
OffsetMS = OffsetMS_c + N × P_BWREQStep + DeltaBWREQBS

The AMS may determine the OffsetMS based on N × P_BWREQStep after N times of retransmission of the bandwidth request preamble code, but this bandwidth request preamble code as described in Equation (20) below. The OffsetMS may be updated using P_BWREQStep for each retransmission, that is, whenever ramping up is performed. Alternatively, each time the DeltaBWREQBS is received from the ABS, the AMS may determine the OffsetMS using the DeltaBWREQBS as described in Equation (21) below.
Formula (20)
OffsetMS = OffsetMS_c + P_BWREQStep
Formula (21)
OffsetMS = OffsetMS_c + DeltaBWREQBS
Here, OffsetMS_c indicates the current value of OffsetMS.

  Meanwhile, the AMS determines the initial value of the offset using the initial ranging process uplink transmission power control method, and determines the periodic ranging process uplink transmission power control method and the bandwidth request preamble code transmission process uplink transmission power control method. The process of using and updating the Offset value has been described. The AMS must notify the ABS of information about the initial value and the update value of the Offset determined directly by the AMS. Here, a method for notifying the ABS of information related to the initial value and update value of Offset determined directly by the AMS will be described in detail below.

  Referring to FIG. 1, an ABS initial ranging process uplink transmission power control operation in an IEEE 802.16m communication system according to an embodiment of the present invention will be described.

  FIG. 1 is a flowchart illustrating an ABS initial ranging process uplink transmission power control operation in an IEEE 802.16m communication system according to an embodiment of the present invention.

  Referring to FIG. 1, in step 111, the ABS broadcasts parameters used for the uplink transmission power control scheme. When the initial ranging code received from the AMS is detected in step 113, the ABS determines a power adjustment value Delta_Initial BS based on the received power of the detected initial ranging code in step 115, and in step 117, the determined power The adjustment value Delta_InitialBS is transmitted to the AMS. In step 119, the ABS receives an initial value of Offset from the AMS.

  With reference to FIG. 2, an AMS initial ranging process uplink transmission power control operation in an IEEE 802.16m communication system according to an embodiment of the present invention will be described.

  FIG. 2 is a flowchart illustrating an initial ranging process uplink transmission power control operation of AMS in an IEEE 802.16m communication system according to an embodiment of the present invention.

  Referring to FIG. 2, the AMS receives parameters used for the uplink transmission power control scheme broadcast from the ABS in step 211, and the uplink transmission power used to transmit the initial ranging code in step 213. Determine PTX_IR_MIN. In step 215, the AMS transmits the initial ranging code using the uplink transmission power PTX_IR_MIN with the initial ranging opportunity. In step 217, the AMS checks whether a response signal to the transmitted initial ranging code is 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 increases the transmission power PTX_IR_MIN by the unit transmission power P_InitialStep used in the initial ranging process in step 219, and In step 215, the initial ranging code is retransmitted using the increased transmission power PTX_IR_MIN.

  In step 217, when a response signal for the transmitted initial ranging code is received from the ABS within a predetermined time, the AMS checks in step 221 whether the power adjustment value Delta_InitialBS is included in the response signal. To do. If the power adjustment value Delta_InitialBS is included in this response signal, the AMS stores the initial ranging code retransmission count N, the unit transmission power P_InitialStep, and the power adjustment value Delta_InitialBS in step 223. In step 225, the AMS checks whether the response signal to the transmitted initial ranging code indicates a successful state. If this response signal indicates a successful state, the AMS proceeds to step 227. On the other hand, if this response signal does not indicate a successful state, ie, indicates a continued state, AMS returns to step 215.

  In step 221, if the power adjustment value Delta_InitialBS is not included in this response signal, the AMS jumps to step 227.

In step 227, the AMS receives an uplink power adjustment value _{PCDMA_allocation} from the ABS. In step 229, the AMS determines an initial value of Offset using one of the methods described in equations (4), (5), and (6). In step 231, the AMS determines the offset of the determined offset. The ABS is notified of the initial value.

  With reference to FIG. 3, an ABS periodic ranging process uplink transmission power control operation in an IEEE 802.16m communication system according to an embodiment of the present invention will be described.

  FIG. 3 is a flowchart illustrating an ABS periodic ranging process uplink transmission power control operation in an IEEE 802.16m communication system according to an embodiment of the present invention.

  Referring to FIG. 3, the ABS broadcasts parameters used for the uplink transmission power control scheme in step 311. If the periodic ranging code received from the AMS is detected in step 313, the ABS determines a power adjustment value DeltaPeriodicBS in step 315 based on the received power of the detected periodic ranging code. In step 317, the determination is made. The power adjustment value DeltaPeriodic BS is transmitted to the AMS. In step 319, the ABS receives the update value of the offset notified by the AMS.

  With reference to FIG. 4, an AMS periodic ranging process uplink transmission power control operation in an IEEE 802.16m communication system according to an embodiment of the present invention will be described.

  FIG. 4 is a flowchart illustrating an AMS periodic ranging process uplink transmission power control operation in an IEEE 802.16m communication system according to an embodiment of the present invention.

  Referring to FIG. 4, in step 411, the AMS receives parameters used for the uplink transmission power control scheme broadcast from the ABS, and in step 413, the uplink used to transmit the periodic ranging code. The transmission power P is determined. In step 415, the AMS transmits the periodic ranging code using the uplink transmission power P with the periodic ranging opportunity. In step 417, the AMS checks whether a response signal to the transmitted periodic ranging code is 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 a predetermined time, the AMS increases the transmission power by the unit transmission power P_PeriodicStep used for the periodic ranging process in step 419. Thus, the transmission power P is updated, and the periodic ranging code is retransmitted using the increased transmission power P in step 415.

  If a response signal for the transmitted periodic ranging code is received from the ABS within a predetermined time in step 417, the AMS determines whether or not the power adjustment value DeltaPeriodic BS is included in the response signal in step 421. Inspect. If the power adjustment value DeltaPeriodic BS is included in the response signal, the AMS uses the periodic ranging code retransmission number N, the unit transmission power P_PeriodicStep, and the power adjustment value DeltaPeriodic BS in step 423 to set the offset value. Update the value. In step 427, the AMS checks whether the response signal to the transmitted periodic ranging code indicates a successful state. If this response signal indicates a successful state, the AMS proceeds to step 429. On the other hand, if this response signal does not indicate a successful state, i.e., indicates a continued state, the AMS returns to step 415.

  If, in step 421, the power adjustment value DeltaPeriodicBS is not included in this response signal, 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 unit transmission power P_PeriodicStep, and then proceeds to step 429. In step 429, the AMS notifies the ABS of the update value of Offset.

  With reference to FIG. 5, an ABS bandwidth request preamble code transmission process uplink transmission power control operation in an IEEE 802.16m communication system according to an embodiment of the present invention will be described.

  FIG. 5 is a flowchart illustrating an uplink transmission power control operation of an ABS bandwidth request preamble code transmission process in an IEEE 802.16m communication system according to an embodiment of the present invention.

  Referring to FIG. 5, in step 511, the ABS broadcasts parameters used for the uplink transmission power control scheme. When the bandwidth request preamble code received from the AMS is detected in step 513, the ABS determines the power adjustment value DeltaBWREQBS based on the received power of the detected bandwidth request preamble code in step 515, and in step 517. The determined power adjustment value DeltaBWREQBS is transmitted to the AMS. In step 519, the ABS receives the update value of the offset notified by the AMS.

  With reference to FIG. 6, an AMS bandwidth request preamble code transmission process uplink transmission power control operation in an IEEE 802.16m communication system according to an embodiment of the present invention will be described.

  FIG. 6 is a flowchart illustrating an AMS bandwidth request preamble code transmission process uplink transmission power control operation in an IEEE 802.16m communication system according to an embodiment of the present invention.

  Referring to FIG. 6, in step 611, the AMS receives parameters used for the uplink transmission power control scheme broadcast from the ABS, and in step 613, the uplink used to transmit the bandwidth request preamble code. The transmission power P is determined. In step 615, the AMS transmits the bandwidth request preamble code using the uplink transmission power P in the bandwidth request preamble code transmission opportunity. In step 617, the AMS checks whether a response signal to the transmitted bandwidth request preamble code is received from the ABS within a predetermined time. If the response signal for the transmitted bandwidth request preamble code is not received from the ABS within a predetermined time, the AMS transmits the unit transmission power P_BWREQStep used in the bandwidth request preamble code transmission process in step 619. In step 615, the bandwidth request preamble code is retransmitted using the increased transmission power P.

  In step 617, if the response signal for the transmitted bandwidth request preamble code is received from the ABS within a predetermined time, the AMS determines in step 621 whether the power adjustment value DeltaBWREQBS is included in the response signal. inspect. When the power adjustment value DeltaBWREQBS is included in this response signal, the AMS uses the bandwidth request preamble code retransmission count N, the unit transmission power P_BWREQStep, and the power adjustment value DeltaBWREQBS to set the value of Offset in step 623. Update. In step 627, the AMS checks whether the response signal for the transmitted bandwidth request preamble code indicates a successful state. If this response signal indicates a successful state, the AMS proceeds to step 629. On the other hand, if the response signal does not indicate a successful state, i.e., indicates a continuing state, the AMS returns to step 615.

  If, in step 621, the power adjustment value DeltaBWREQBS is not included in this response signal, the AMS proceeds to step 625. In step 625, the AMS updates the value of Offset using the number N of retransmissions of the bandwidth request preamble code and the unit transmission power P_BWREQStep. In step 629, the AMS notifies the ABS of the updated value of Offset.

  With reference to FIG. 7, the structure of the ABS in the IEEE 802.16m communication system according to the embodiment of the present invention will be described.

  FIG. 7 is a diagram illustrating a configuration of an ABS in an IEEE 802.16m communication system according to an 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 to implement the embodiments of the present invention, which are not separately illustrated.

  The controller 713 controls the overall operation of the ABS. The controller 713 controls all operations of the ABS according to the initial ranging process uplink transmission power control scheme, the periodic ranging process uplink transmission power control scheme, and the bandwidth request preamble code transmission process uplink transmission power control scheme, Since this was mentioned above, the detailed description is abbreviate | omitted.

  Further, the controller 713 performs uplink transmission through the transmitter 715 in the initial ranging process uplink transmission power control scheme, the periodic ranging process uplink transmission power control scheme, and the bandwidth request preamble code transmission process uplink transmission power control scheme. Since transmission of various parameters necessary for controlling power is controlled and described above, detailed description thereof is omitted.

  The receiver 711 uses the initial ranging process uplink transmission power control scheme, the periodic ranging process uplink transmission power control scheme, and the bandwidth request preamble code transmission process uplink transmission power control scheme to generate uplink transmission power. Various parameters necessary for control are received from the AMS, and since this has been described above, a detailed description thereof will be omitted. The memory 717 stores various information necessary for the operation of the ABS.

  Although the receiver 711, controller 713, transmitter 715, and memory 717 are shown in FIG. 7 as separate units, the receiver 711, controller 713, transmitter 715, and memory 717 are one unit. It is obvious that it can also be incorporated into

  With reference to FIG. 8, the configuration of the AMS in the IEEE 802.16m communication system according to the embodiment of the present invention will be described.

  FIG. 8 is a block diagram showing a configuration of an AMS in the IEEE 802.16m communication system according to the 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 to implement the embodiments of the present invention, which are not shown in FIG.

  The controller 813 controls the overall operation of the AMS. The controller 813 controls all operations of the AMS according to the initial ranging process uplink transmission power control scheme, the periodic ranging process uplink transmission power control scheme, and the bandwidth request preamble code transmission process uplink transmission power control scheme, Since this was mentioned above, the detailed description is abbreviate | omitted.

  Further, the controller 813 performs uplink transmission through the transmitter 815 in the initial ranging process uplink transmission power control scheme, the periodic ranging process uplink transmission power control scheme, and the bandwidth request preamble code transmission process uplink transmission power control scheme. Since transmission of various parameters necessary for controlling power is controlled and described above, detailed description thereof is omitted.

  The receiver 811 uses the initial ranging process uplink transmission power control scheme, the periodic ranging process uplink transmission power control scheme, and the bandwidth request preamble code transmission process uplink transmission power control scheme to generate uplink transmission power. Various parameters necessary for the control are received from the ABS, and since this has been described above, a detailed description thereof will be omitted. The memory 817 stores various information necessary for AMS operation.

  Although the receiver 811, controller 813, transmitter 815, and memory 817 are shown in FIG. 8 as separate units, the receiver 811, controller 813, transmitter 815, and memory 817 are one unit. It is obvious that it can also be incorporated into

On the other hand, as described above, the AMS that has successfully executed the initial ranging process uses the uplink resource allocated by the CDMA allocation A-MAP IE, after determining the initial value of Offset, as described above. Hereinafter referred to as “RNG-REQ”). The AMS includes the initial value of the offset determined by the AMS in the RNG-REQ message, so that the difference between the uplink path loss and the downlink path loss calculated by the AMS and between the uplink path loss and the downlink path loss are calculated. It is possible to determine the actual transmission power of the AMS reflecting the difference. Therefore, the ABS can perform scheduling accurately. According to an embodiment of the present invention, it is assumed that the initial value of Offset is fed back once through the RNG-REQ message after the AMS has succeeded in the initial ranging process. Here, the initial value of Offset may be included in the RNG-REQ message in the form of an Initial Offset for uplink power control (Offset _Initial ) field as shown in Table 1 below.

In Table 1 described above, the Initial Offset for uplink power control (Offset _Initial ) is specified by a power level, for example, 5 bits. Also, Initial Offset for uplink power
The power level indicated by control (Offset _Initial ) is determined by the AMS that has successfully performed the initial ranging process.

  Although the present invention has been described in detail with reference to specific embodiments, it will be apparent to those skilled in the art that various modifications can be made without departing from the scope and spirit of the invention. The scope of the present invention should not be limited to the above-described embodiments, but should be defined within the scope of the appended claims and their equivalents.

711 Receiver 713 Controller 715 Transmitter 717 Memory 811 Receiver 813 Controller 815 Transmitter 817 Memory

Claims (28)

A method for controlling the up-link power of that put the mobile communication system moving terminal (M S),
A through Michison loss, uplinks noise and interference level, a target signal to interference noise ratio (SINR), and determining the up-link power based on the offset,
Initial offset value, the number of times the ramp-up until the initial ranging process is completed (ramp-up), a power step size for ramp-up (power step size), the power received from the base Chikyoku (BS) adjustment value and uplinks power control method that moves the terminal to being determined on the basis of. The initial offset value, moving terminal of the up-link power control method according to claim 1, characterized in that it is represented by the following formula.
Formula (1)
Offset _Data = PTX_IR_Final− (L + SINR _Target + NI) −10 log 10 (NumSubcarrierRNG)
Offset _Control = PTX_IR_Final− (L + SINR _Target + NI) −10 log 10 (NumSubcarrierRNG)
Here, _{Offset Data,} when applied to the uplinks power is de data signal indicates an initial offset value for the data _{signal, Offset Control} is in the up link power is controlled signal If applicable, shows the initial offset value for the control signal, L is shown the path _{loss, SINR target} denotes the target SINR, NI denotes the uplink noise and interference level, NumSubcarrierRNG Indicates the total number of subcarriers included in the bandwidth used for initial ranging, and PTX_IR_Final is expressed by the following equation.
Formula (2)
PTX_IR_Final = PTX_IR_MIN + N × P_InitialStep + ΣDelta_InitialBS (m)
Here, PTX_IR_MIN is pre KiUtsuri dynamic terminal indicates that Ru power to be used in transmitting the initial ranging code before Kimoto ground station, N is the, indicates the number of times of the ramp-up, P_InitialStep the power shows the step size, Delta_InitialBS shows the power adjustment value, Delta_InitialBS (m) represents the m-th power adjustment value received by the MS. The target SINR, moving terminal of the up-link power control method according to claim 1, characterized in that it has a target SINR of the asynchronous ranging channel. The offset is moved terminal of the up-link power control method according to claim 1, characterized in that it has a value that compensates for differences between the downlink path loss and the uplink path loss. Ranging request (RNG-REQ) uplinks power control of mobile terminals machine according to claim 1, further comprising the step of transmitting a message before Kimoto land stations including the initial offset value Method.   The uplink power control method of claim 1, wherein the uplink noise and interference level and the offset are received from the base station.   The method of claim 1, wherein the power adjustment value is received through a ranging acknowledgment (RNG-ACK) message. A method that put the mobile communication system based on Chikyoku (B S) supports uplinks power control of mobile terminals machine (M S),
And transmitting the power adjustment value before KiUtsuri dynamic terminal,
Before and a step of receiving the initial offset value from KiUtsuri moving terminal,
Determining the initial offset value, the number of times the lamp up until the initial ranging process completion (ramp-up), a power step size for ramp-up (power step size), based on said power adjustment how the group Chikyoku you characterized supports uplinks power control of mobile terminals machine to be. Uplink noise and interference level, a target signal to interference noise ratio (SINR), and further comprising the step of transmitting an offset before KiUtsuri dynamic terminal,
The up link power is through Michison loss, the uplink noise and interference level is determined based on the target SINR, and the offset,
The path loss, a method based Chikyoku of claim 8 supports uplinks power control of mobile terminals machine, characterized in that it is measured by pre KiUtsuri dynamic terminal. The initial offset value, a method based Chikyoku according to claim 9, characterized in that it is represented by the following formula supports uplinks power control of mobile terminals machine.
Formula (3)
Offset _Data = PTX_IR_Final− (L + SINR _Target + NI) −10 log 10 (NumSubcarrierRNG)
Offset _Control = PTX_IR_Final− (L + SINR _Target + NI) −10 log 10 (NumSubcarrierRNG)
Here, _{Offset Data,} when applied to the uplinks power is de data signal indicates an initial offset value for the data _{signal, Offset Control} is in the up link power is controlled signal If applicable, shows the initial offset value for the control signal, L is shown the path _{loss, SINR target} denotes the target SINR, NI denotes the uplink noise and interference level, NumSubcarrierRNG Indicates the total number of subcarriers included in the bandwidth used for initial ranging, and PTX_IR_Final is expressed by the following equation.
Formula (4)
PTX_IR_Final = PTX_IR_MIN + N × P_InitialStep + ΣDelta_InitialBS (m)
Here, PTX_IR_MIN is pre KiUtsuri dynamic terminal indicates that Ru power to be used in transmitting the initial ranging code before Kimoto ground station, N is the a number of times the ramp-up (ramp-up) shows, P_InitialStep shows a power step size, D Elta_InitialBS shows the power adjustment value, Delta_InitialBS (m) represents the m-th power adjustment value received by the MS. The target SINR, a method of group Chikyoku of claim 9 supports uplinks power control of moving terminal characterized by having a target SINR of the asynchronous ranging channel. The offset supports uplinks power control group Chikyoku is moving terminal according to claim 9, characterized in that it has a value that compensates for differences between the downlink path loss and the uplink path loss how to. The method of claim 8, wherein the power adjustment value is transmitted through a ranging acknowledgment (RNG-ACK) message. The method of claim 8, wherein the initial offset value is received through a ranging request (RNG-REQ) message. A mobile terminal (MS) in a mobile communication system,
A controller that determines uplink power based on path loss, uplink noise and interference level, target signal to interference noise ratio (SINR), and offset;
The initial offset value includes the number of ramp-ups until the initial ranging process is completed, the power step size for the ramp-up, and the power adjustment value received from the base station (BS). A mobile terminal that is determined based on The mobile terminal of claim 15, wherein the initial offset value is expressed by the following equation.
Formula (5)
Offset _Data = PTX_IR_Final- (L + SINR _Target + NI) -10 log 10 (NumSubcarrierRNG)
Offset _Control = PTX_IR_Final- (L + SINR _Target + NI) -10 log 10 (NumSubcarrierRNG)
Where Offset _Data Indicates an initial offset value for the data signal when the uplink power is applied to the data signal, and Offset _Control Indicates the initial offset value for the control signal when the uplink power is applied to the control signal, L indicates the path loss, and SINR _Target Indicates the target SINR, NI indicates the uplink noise and interference level, NumSubcarrierRNG indicates the total number of subcarriers included in the bandwidth used for initial ranging, and PTX_IR_Final is expressed by the following equation: Is done.
Formula (6)
PTX_IR_Final = PTX_IR_MIN + N × P_InitialStep + ΣDelta_InitialBS (m)
Here, PTX_IR_MIN represents power used when the mobile terminal transmits an initial ranging code to the base station, N represents the number of ramp-ups, P_InitialStep represents a power step size, and Delta_InitialBS. Indicates the power adjustment value, and Delta_InitialBS (m) indicates the mth power adjustment value received by the MS. The mobile terminal of claim 15, wherein the target SINR includes a target SINR of an asynchronous ranging channel. The mobile terminal of claim 15, wherein the offset has a value that compensates for a difference between a downlink path loss and an uplink path loss. The mobile terminal of claim 15, further comprising a transmitter that transmits a ranging request (RNG-REQ) message including the initial offset value to the base station. The mobile terminal of claim 15, wherein the uplink noise and interference level and the offset are received from the base station. The mobile terminal of claim 15, wherein the power adjustment value is received through a ranging acknowledgment (RNG-ACK) message. A base station (BS) in a mobile communication system,
A transmitter for transmitting a power adjustment value to a mobile terminal (MS);
A receiver for receiving an initial offset value from the mobile terminal,
The initial offset value is determined based on the number of ramp-ups until the initial ranging process is completed, a power step size for the ramp-up, and the power adjustment value. Base station characterized by The transmitter transmits uplink noise and interference level, target signal to interference noise ratio (SINR), and offset to the mobile terminal;
The uplink power is determined based on path loss, the uplink noise and interference level, the target SINR, and the offset;
The base station of claim 22, wherein the path loss is measured by the mobile terminal. The base station according to claim 23, wherein the initial offset value is expressed by the following equation.
Formula (7)
Offset _Data = PTX_IR_Final- (L + SINR _Target + NI) -10 log 10 (NumSubcarrierRNG)
Offset _Control = PTX_IR_Final- (L + SINR _Target + NI) -10 log 10 (NumSubcarrierRNG)
Where Offset _Data Indicates an initial offset value for the data signal when the uplink power is applied to the data signal, and Offset _Control Indicates the initial offset value for the control signal when the uplink power is applied to the control signal, L indicates the path loss, and SINR _Target Indicates the target SINR, NI indicates the uplink noise and interference level, NumSubcarrierRNG indicates the total number of subcarriers included in the bandwidth used for initial ranging, and PTX_IR_Final is expressed by the following equation: Is done.
Formula (8)
PTX_IR_Final = PTX_IR_MIN + N × P_InitialStep + ΣDelta_InitialBS (m)
Here, PTX_IR_MIN indicates power used when the mobile terminal transmits an initial ranging code to the base station, N indicates the number of ramp-ups, and P_InitialStep indicates power. The step size is indicated, Delta_InitialBS indicates the power adjustment value, and Delta_InitialBS (m) indicates the mth power adjustment value received by the MS. The base station according to claim 23, wherein the target SINR includes a target SINR of an asynchronous ranging channel. The base station of claim 23, wherein the offset has a value that compensates for a difference between a downlink path loss and an uplink path loss. The base station of claim 22, wherein the power adjustment value is transmitted through a ranging acknowledgment (RNG-ACK) message. The base station of claim 22, wherein the initial offset value is received through a ranging request (RNG-REQ) message.

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