KR20130018704A - Terminal and method for controlling uplink transmission power - Google Patents

Abstract

PURPOSE: A terminal device for controlling uplink transmission power and a method thereof are provided to effectively determine the uplink transmission power through a base station. CONSTITUTION: A receiving antenna receives a first message. The first message includes an interference level in a frequency partition allocated from an S-ABS(Serving-Advanced Base Station) or a T-ABS(Target-Advanced Base Station). A processor(155) determines a transmission power value for transmitting an uplink signal to the T-ABS by using the interference level. The transmission antenna transmits the uplink signal to the T-ABS through the determined transmission power value. [Reference numerals] (105) Base station; (110) Terminal; (115,165) Tx data processor; (120,170) Symbol modulator; (125,175) Transmitter; (140,190) Receiver; (145,195) Symbol demodulator; (150,197) Rx data processor; (155,180) Processor; (185,160) Memory; (AA) Downlink pilot

Description

Terminal device for controlling uplink transmission power and a method thereof {TERMINAL AND METHOD FOR CONTROLLING UPLINK TRANSMISSION POWER}

The present invention relates to wireless communication, and more particularly, to a terminal apparatus and method for controlling uplink transmission power.

Handover (HO) refers to a terminal moving from a radio interface of one base station to a radio interface of another base station. Hereinafter, a handover procedure in a general IEEE 802.16e system will be described.

In an IEEE 802.16e network, a serving base station (SBS) may broadcast neighbor base station information through a neighbor announcement (MOB_NBR-ADV) message to inform the terminal of information (topology) about basic network configuration. . The MOB_NBR-ADV message includes system information about the serving base station and neighbor base stations, for example, preamble index, frequency, HO optimization possibility, and downlink channel descriptor / DCD. (Uplink Channel Descriptor) information and the like.

The DCD / UCD information includes information that the terminal needs to know in order to perform information communication through downlink and uplink in the terminal. For example, there is information such as handover trigger (HO trigger) information, a medium access control version (MAC) of the base station, and media independent handover capability (MIH).

The general MOB_NBR-ADV message includes only information on neighbor base stations of the IEEE 802.16e type. Accordingly, neighbor base station information having a type other than IEEE 802.16e may be broadcast to terminals through a SII-ADV (Service Identity Information ADVertisement) message. Accordingly, the terminal may obtain information on the heterogeneous network base station by requesting the serving base station to transmit the SII-ADV message.

Many power control parameters are required for the UE to determine uplink transmission power. Accordingly, the terminal needs to receive many power control parameters signaled from the base station during the handover. However, the interruption time during handover is expected to be approximately 25ms, which is a great overhead for receiving all power control parameters in a fairly short time. However, there have been no studies and disclosures on the content of determining and controlling transmission power for uplink transmission after handover while reducing overhead.

An object of the present invention is to provide a method for controlling uplink transmission power of a terminal.

Another object of the present invention is to provide a terminal device for controlling uplink transmission power.

The technical problems to be solved by the present invention are not limited to the technical problems and other technical problems which are not mentioned can be understood by those skilled in the art from the following description.

In order to achieve the above technical problem, in a frequency partition allocated to the terminal from a Serving-Advanced Base Station (S-ABS) or a Target-Advanced Base Station (T-ABS) according to the present invention. Receiving a first message comprising an interference level; Determining a transmission power value for uplink signal transmission to the target-advanced base station (T-ABS) using the interference level; And transmitting an uplink signal to the target base station at the determined transmission power value.

The first message may further include an offset value corresponding to a power correction value for uplink signal transmission to the target base station, and the transmission power value may be determined using the interference level and the offset value.

The first message may be an AAI-HO-CMD message type or a CDMA Allocation A-MAP IE message type.

The uplink signal transmission is a first uplink signal transmission to the target base station after handover completion, uplink transmission power control method.

If the first message is an AAI-HO-CMD message type, the step of determining the transmit power value is further determined using remaining power control parameters other than the interference level and the offset value, and the value of the remaining power control parameters is determined by the method. Is the value of the remaining power control parameters of the serving base station.

If the first message is a CDMA Allocation A-MAP IE message type, the step of determining the transmit power value is further determined using the remaining power control parameters other than the interference level and the offset value, and the value of the remaining power control parameters is This is a predefined default value.

The offset value may be a power correction value for data channel transmission to the target base station or a power correction value for control channel transmission to the target base station.

In order to achieve the above another technical problem, a terminal apparatus for controlling uplink transmission power is provided from a serving base station (S-ABS) or a target base station (Target-Advanced Base Station (T-ABS)). A receiving antenna for receiving a first message comprising an interference level in an assigned frequency partition; A processor for determining a transmission power value for uplink signal transmission to the target-advanced base station (T-ABS) using the interference level; And a transmission antenna configured to transmit an uplink signal to the target base station at the determined transmission power value.

If the first message is an AAI-HO-CMD message type, the processor further determines the transmit power value using the remaining power control parameters other than the interference level and the offset value, wherein the value of the remaining power control parameters is determined. May be a value of the remaining power control parameters of the serving base station.

If the first message is a CDMA Allocation A-MAP IE message type, the processor further determines the transmit power value using remaining power control parameters other than the interference level and the offset value, wherein the remaining power control parameter The value of these may be a predetermined default value.

According to various embodiments of the present invention, the base station can efficiently support the terminal in the handover to determine the transmission power for uplink transmission after the handover is completed. And, the terminal can efficiently determine the transmission power for uplink transmission after the handover is completed using the power control parameter received from the base station.

Effects obtained in the present invention are not limited to the above-mentioned effects, and other effects not mentioned above may be clearly understood by those skilled in the art from the following description. will be.

BRIEF DESCRIPTION OF THE DRAWINGS The accompanying drawings, which are included as part of the detailed description in order to provide a thorough understanding of the present invention, provide an embodiment of the present invention and together with the description, illustrate the technical idea of the present invention.
1 is a block diagram showing the configuration of a base station 105 and a terminal 110 in a wireless communication system 100,
2 is a diagram illustrating an example of a process of performing a handover procedure by a terminal in an IEEE 802.16m system, which is an example of a mobile communication system;
3 is a diagram illustrating another example of a process of performing a handover procedure by a terminal in an IEEE 802.16m system as an example of a mobile communication system.

Hereinafter, preferred embodiments according to the present invention will be described in detail with reference to the accompanying drawings. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The following detailed description, together with the accompanying drawings, is intended to illustrate exemplary embodiments of the invention and is not intended to represent the only embodiments in which the invention may be practiced. The following detailed description includes specific details in order to provide a thorough understanding of the present invention. However, those skilled in the art will appreciate that the present invention may be practiced without these specific details. For example, the following detailed description assumes that a mobile communication system is a 3GPP LTE and an LTE-A system. However, other than specific aspects of 3GPP LTE and LTE-A, Applicable.

In some instances, well-known structures and devices may be omitted or shown in block diagram form centering on the core functions of the structures and devices in order to avoid obscuring the concepts of the present invention. In addition, the same components will be described with the same reference numerals throughout the present specification.

In the following description, it is assumed that the UE collectively refers to a mobile stationary or stationary user equipment such as a UE (User Equipment), an MS (Mobile Station), and an AMS (Advanced Mobile Station). It is also assumed that the base station collectively refers to any node at a network end that communicates with a terminal such as a Node B, an eNode B, a base station, and an access point (AP). Although described herein based on the IEEE 802.16m system, the contents of the present invention can be applied to various other communication systems.

In a mobile communication system, a user equipment can receive information through a downlink from a base station, and the terminal can also transmit information through an uplink. The information transmitted or received by the terminal includes data and various control information, and various physical channels exist depending on the type of information transmitted or received by the terminal.

1 is a block diagram showing the configuration of a base station 105 and a terminal 110 in a wireless communication system 100. As shown in FIG.

Although one base station 105 and one terminal 110 are shown to simplify the wireless communication system 100, the wireless communication system 100 may include one or more base stations and / or one or more terminals. .

1, a base station 105 includes a transmit (Tx) data processor 115, a symbol modulator 120, a transmitter 125, a transmit / receive antenna 130, a processor 280, a memory 285, a receiver 290, a symbol demodulator 295, and a receive data processor 297. The terminal 110 includes a transmission (Tx) data processor 165, a symbol modulator 275, a transmitter 275, a transmission / reception antenna 135, a processor 155, a memory 160, a receiver 140, A demodulator 155, and a receive data processor 150. Although the transmission / reception antennas 130 and 135 are shown as one in the base station 105 and the terminal 110, respectively, the base station 105 and the terminal 110 have a plurality of transmission / reception antennas. Accordingly, the base station 105 and the terminal 110 according to the present invention support a multiple input multiple output (MIMO) system. In addition, the base station 105 according to the present invention can support both a Single User-MIMO (SU-MIMO) and a Multi User-MIMO (MIMO) scheme.

On the downlink, the transmit data processor 115 receives traffic data, formats, codes, and interleaves and modulates (or symbol maps) the coded traffic data to generate modulation symbols Symbols "). A symbol modulator 120 receives and processes the data symbols and pilot symbols to provide a stream of symbols.

The symbol modulator 120 multiplexes the data and pilot symbols and transmits it to the transmitter 125. In this case, each transmission symbol may be a data symbol, a pilot symbol, or a signal value of zero. In each symbol period, the pilot symbols may be transmitted continuously. The pilot symbols may be frequency division multiplexed (FDM), orthogonal frequency division multiplexed (OFDM), time division multiplexed (TDM), or code division multiplexed (CDM) symbols.

Transmitter 125 receives the stream of symbols and converts it to one or more analog signals and further modulates (e.g., amplifies, filters, and frequency upconverts) The transmission antenna 130 transmits the generated downlink signal to the mobile station.

In the configuration of the terminal 110, the reception antenna 135 receives the downlink signal from the base station and provides the received signal to the receiver 140. The receiver 140 adjusts (e.g., filters, amplifies, and downconverts) the received signal and digitizes the conditioned signal to obtain samples. The symbol demodulator 145 demodulates the received pilot symbols and provides it to the processor 155 for channel estimation.

Symbol demodulator 145 also receives a frequency response estimate for the downlink from processor 155 and performs data demodulation on the received data symbols to obtain a data symbol estimate (which is estimates of the transmitted data symbols) And provides data symbol estimates to a receive (Rx) data processor 150. [ The receive data processor 150 demodulates (i.e., symbol demaps), deinterleaves, and decodes the data symbol estimates to recover the transmitted traffic data.

The processing by symbol demodulator 145 and receiving data processor 150 is complementary to the processing by symbol modulator 120 and transmitting data processor 115 at base station 105, respectively.

The terminal 110 is on the uplink, and the transmit data processor 165 processes the traffic data to provide data symbols. The symbol modulator 170 may receive and multiplex data symbols, perform modulation, and provide a stream of symbols to the transmitter 175. A transmitter 175 receives and processes the stream of symbols to generate an uplink signal. The transmission antenna 135 transmits the generated uplink signal to the base station 105.

In the base station 105, an uplink signal is received from a terminal 110 via a receive antenna 130, and a receiver 190 processes the received uplink signal to obtain samples. The symbol demodulator 195 then processes these samples to provide received pilot symbols and data symbol estimates for the uplink. The receive data processor 197 processes the data symbol estimates to recover the traffic data transmitted from the terminal 110.

Processors 155 and 180 of the terminal 110 and the base station 105 respectively instruct (eg, control, coordinate, manage, etc.) operations at the terminal 110 and the base station 105, respectively. Respective processors 155 and 180 may be connected to memory units 160 and 185 that store program codes and data. The memory 160, 185 is coupled to the processor 180 to store the operating system, applications, and general files.

Processors 155 and 280 may also be referred to as controllers, microcontrollers, microprocessors, microcomputers, and the like. Meanwhile, the processors 155 and 180 may be implemented by hardware or firmware, software, or a combination thereof. (DSP), digital signal processing devices (DSPDs), programmable logic devices (PLDs), and the like may be used to implement embodiments of the present invention using hardware, , FPGAs (field programmable gate arrays), and the like may be provided in the processors 155 and 180.

Meanwhile, when implementing embodiments of the present invention using firmware or software, firmware or software may be configured to include modules, procedures, or functions that perform the functions or operations of the present invention. Firmware or software configured to be stored in the memory 155 may be contained within the processor 155 or 180 or may be stored in the memory 160 or 185 and be driven by the processor 155 or 180. [

Layers of a wireless interface protocol between a terminal and a base station and a wireless communication system (network) are divided into a first layer (L1), a second layer (L2) based on the lower three layers of an open system interconnection ), And a third layer (L3). The physical layer belongs to the first layer and provides an information transmission service through a physical channel. An RRC (Radio Resource Control) layer belongs to the third layer and provides control radio resources between the UE and the network. The UE and the base station can exchange RRC messages through the RRC layer with the wireless communication network.

Hereinafter, a method for a UE to determine uplink transmission power using the following Equation 1 in an IEEE 802.16m system, which is an example of a mobile communication system, will be briefly described. In general, the UE needs to determine an uplink transmission power value when transmitting an uplink signal.

Here, P represents a transmission power level (in dBm units) for each subcarrier and stream for the current transmission, and L represents a current average downlink propagation loss estimated by the terminal. L includes the transmit antenna gain and path loss of the terminal. SINR _Target is a target uplink signal to interference plus noise ratio (SINR) value received from a base station. NI is an average noise and interference level (in dBm) per subcarrier estimated by the base station, and is a value received by the terminal from the base station. Offset is a correction term for power offset for each terminal. The offset values are transmitted on the power control message from the base station, to present these two types of offset value one has an offset value of Offsetcontrol Offsetdata, control information, the offset value used for transmission is used for data transmission.

In applying Equation 1, in the case of a control channel for transmitting control information, the terminal previously defines a target signal to noise and interference ratio (SINR) value corresponding to the control channel. Applicable immediately using Table 1.

However, when the terminal transmits data, it is necessary to set the target SINR value using the following equation (2).

Here, SINR _MIN (dB) is a minimum SINR value required by the base station and is a value set in a unicast power control message. SINR _MIN is represented by 4 bits, the value of which is one of {-∞, -3, -2.5, -1, 0, 0.5, 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5} Can be the value of. SIR _DL means a ratio of downlink signal to interference power measured by the terminal.

γ _IoT is fairness and IoT control factor and the base station broadcasts to the terminal. Alpha (α) is a coefficient according to the number of receiving antennas at the base station and is signaled in 3 bits as MAC power control mode signaling, where the value is, for example, {1, 1/2, 1/4, 1/8, 1 / 16, 0}. Beta (β) may be set to 0 or 1 by 1 bit of MAC power control mode signaling.

TNS is the total number of streams in the Logical Resource Unit (LRU) indicated by UL-A-MAP IE. In the case of SU-MIMO (Single User-MIMO), this value is set to Mt, where Mt is the number of streams per user. For CSM, this value is set to TNS and is the total number of streams. In the case of control channel transmission, this value may be set to one.

As such, the processor 155 of the terminal may determine the uplink transmission power using L, NI, offset, and SINR _target values.

Hereinafter, a method for determining uplink transmission power in order to facilitate faster uplink transmission when the terminal is in the process of handover. First, the handover procedure is briefly described.

2 and 3 are diagrams illustrating an example of a process of performing a handover procedure by a terminal in an IEEE 802.16m system, which is an example of a mobile communication system.

In the handover process illustrated in FIG. 2, the HO_Reentry_Mode parameter is set to 1, and the UE continuously communicates with the serving base station (S-ABS) at the action time at the time of network reentry (ie, handover). Network reentry (T-ABS). However, the terminal stops communicating with the serving base station after network reentry to the target base station is completed. Also, the terminal does not exchange data with the target base station before network reentry is completed. In the handover process shown in FIG. 2, the handover interruption time is expected to be approximately 25 ms.

Next, the handover process illustrated in FIG. 3 is a case where the HO_Reentry_Mode parameter is set to zero. In this handover process, the UE performs network reentry to the target base station (T-ABS) without communicating with the serving base station (S-ABS) at the action time at the time of network reentry (ie, handover). This is different from the case of FIG. Also in this case, as in FIG. 2, the handover interruption time is expected to be approximately 25 ms.

As such, it is difficult for the UE to receive all the parameters necessary for determining the uplink transmission power within the interruption time when performing the handover. If, when the terminal is performing a handover from the serving base station to the target base station, it is not possible to receive all of the parameters necessary for power control from the target base station within a certain time, it may not support the handover requirements (requirement) smoothly do. Here, the handover requirement may be defined as a handover interruption time. That is, the handover interruption time may be regarded as the time when the terminal starts handover to the target base station until the first base station transmits downlink channel information. As mentioned above, IEEE 802.16m expects about 25ms as the handover interruption time.

Hereinafter, a method for efficiently determining an uplink transmission power for uplink first transmission to a target base station after the handover is completed and a method of transmitting power control parameters of the base station for supporting the same will be described. In the present invention, since the base station to be handed over may be configured by one or a combination of several base stations, the information configuration of power parameters may be configured by a combination of one or several base stations.

1st Example

In an IEEE 802.16m system, which is an example of a mobile communication system, an AAI-HO-CMD message is a message that a serving base station needs to send to a terminal to start a handover procedure or a handover request message sent by the terminal (AAI-HO-REQ message). This is a response message. The serving base station may transmit an offset value, which is an item indicated in Equation 1, in the AAI-HO-CMD message to the terminal. The UE may determine the uplink transmission power so that the target base station can maintain the transmission power density (PSD) level (or calculated power) using the offset value. During handover, the serving base station informs the terminal of a power gap between the serving base station and the target base station through an AAI-HO-CMD message, so that the terminal does not know the power control parameter of the target base station, but the first base station at the target base station does not know. First transmission is possible. That is, the processor 155 of the terminal may determine the uplink transmission power value for the first uplink transmission after the handover based on the power difference value with the target base station received from the serving base station. Subsequently, when the terminal does not receive the AAI-SCD message or the NI message, the target base station sends a transmit power control command (TPC command) to the terminal based on the last transmitted PSD level, and transmits the terminal. You can adjust the PSD level. The TPC command may be transmitted to the terminal through a PC-A-MAP or an AAI_UL_POWER_ADJUST message.

As mentioned above, the offset value to be included in the AAI-HO-CMD message may consist of information on one target base station or handover base station sets. The offset values may be included in the uplink transmission power control equations as respective power correction values for uplink transmission to the serving base station and the target base station, as shown in Equations 3 and 4 below.

Equation 3 shows the PSD level (or calculated total power) at the serving base station, and Equation 4 shows the PSD level (or calculated total power) at the target base station.

In case of a UE performing seamless handover, it may be assumed that path loss components (ie, L _S and L _T ) are similar in Equations 3 and 4 under the assumption that coverage is the same. And the UE is SINR _Target Differences in values, differences in NI values, and Offset_s values can also be calculated. To support this, the base stations can share the parameters related to the uplink transmission power control of the terminal in advance, and include these shared uplink transmission power control related parameters in the AAI-NBR-ADV message for the handover terminal. I can send it. In addition, when sharing the uplink transmission power control-related parameters between the base stations, it is also possible for the base station to calculate the power control parameters value to inform the terminal. If the value of the power control parameters are included in the AAI-NBR-ADV message, the handover terminal may calculate and apply the value directly. The range of the offset value may be determined in a high layer, and may be defined in units of dB or in a linear value.

Second Example

In the present embodiment, the serving base station may inform the terminal immediately before or after handing over the uplink power control parameters associated with the target base station. Among the uplink power control parameters, for example, Beta (β), TNS, etc., are information necessary for power control, but are not important and urgent power control parameters when handing over, so the serving base station transmits these power control parameter values except these values. It may be desirable to. However, in some cases, the serving base station may transmit two parameters to the terminal. The list of power control parameters transmitted from the serving base station to the terminal at handover may be configured as shown in Table 2 below.

The serving base station may transmit one or more of the power control parameter list shown in Table 2 to the UE in an AAI-NBR-ADV message. Alternatively, the serving base station may unicast / broadcast to the terminal as a new type of message rather than an AAI-NBR-ADV message at the action time of the terminal performing the handover. Alternatively, the serving base station may inform the terminal by including one or more of the list of power control parameters shown in Table 2 in the AAI-HO-CMD message. As mentioned, the serving base station may inform the terminal of all or some of the power control parameter list of Table 2 above, and in particular, transmit information except for information related to uplink control or information related to sounding. It may be.

The processor 155 of the UE receives the power control parameters of Table 2 through a specific message (eg, AAI-HO-CMD message) from the serving base station and applies these values to uplink to the target base station after the handover. The transmission power for the first transmission can be determined.

Third Example

In the above-described second embodiment, the serving base station proposes a method for notifying the handover terminal by including all power control parameters in one message. However, there is a disadvantage in that the serving base station transmits all of the power control parameters in one message. Therefore, the present embodiment proposes a method for the serving base station to optimize the control overhead and transmit it to the terminal.

Among the power control parameters described in Table 2, the value may be extended depending on whether or not a partial frequency reuse (FFR) scheme is applied. For example, there are GAMMA_IOT_FPx and IOT_FPx. Information about the frequency partitions may be unnecessary for the terminal at the time of handover. Therefore, the serving base station configures only one GAMMA_IOT and one IOT_FP among the power control parameters. Of course, it is assumed that the base stations and the terminal know the mapping relationship between the corresponding FP (Frquency Partition) index implicitly or explicitly (for example, the corresponding FP index (2 bits) when four FPs exist). It is.

However, it is not necessary for the terminal to know which FP the power control parameters informed by the target base station are related to. The target base station may allocate the uplink resource allocation of the terminal to the FP of the parameters. That is, the target base station only informs the power control information of a specific FP during handover, and promises in advance where the FP is (e.g., FP 0 or power-boosting reuse 3 FP). May be informed to the terminal through signaling. For example, when the FP is configured as 2, the target base station may inform the terminal of the handover FP with a 1-bit indicator. As another example, when the FP is 4, the target base station may inform the terminal of the power boosted region as a 1-bit indicator.

Fourth Example

The present embodiment relates to a method of further optimizing and transmitting power control parameter lists according to the third embodiment. That is, in this embodiment, the serving base station may transmit a list composed of only power control parameters that are necessary and urgent at the time of handover. This is possible by optimizing the parameter information for the control channel. To this end, the terminal is basically based on the transmission of the UL sounding channel (band sound request), bandwidth request (Bandwidth request), SyncRaing channel immediately after the handover. Therefore, since the UE is likely to send downlink channel information or HARQ (Hybrid Automatic Repeat reQuest) response immediately after the handover, the serving base station forms a list only with information related to an urgent power control parameter and transmits the list to the UE. Can give In this case, the serving base station may configure the power control parameter list with the amount of information shown in Table 3 below. Information on control channels may be included or excluded depending on the urgency. The information of power parameters according to Table 3 may be configured by a combination of one or several base stations.

5th Example

In this embodiment, in order to reduce the amount of information in the configuration method as in the second to fourth embodiments according to the present invention, it is proposed that the serving base station transmits only information related to the data channel or only information related to the control channel. This assumes that the handover terminal does not transmit the control channel and the data channel at the same time. Of course, both terminals can inform all the information.

6th Example

In the present embodiment, a value for changing the setting value of the power control parameters configured in the second to fifth embodiments according to the present invention into a static value and a semi-static value for each base station is dynamically changed. dynamically) change values separately The serving base station may transmit the separately configured power control parameters to the terminal through a separate message. For example, the value of IOT_FPx is updated with a period / aperiod of 1 second or several seconds. Of course, other values can also change dynamically.

Accordingly, the serving base station may transmit a fixed value or a semi-fixed value to the terminal by including it in the AAI-NBR-ADV message and inform the terminal by including the dynamically changing value in the AAI-HO-CMD message. IOT_FPx is based on receiving the latest value of the target base station. This is based on what the terminal knows through base station communication. In another method, when the serving base station sends a handover request to the target base station at the time of handover, when the target base station sends a handover response to the serving base station, the updated IOT_FPx information may be transmitted to the terminal. This may be viewed as being updated rather than information exchanged between base stations. Therefore, the serving base station may transmit the information to the UE in the AAI-HO-CMD message.

Table 4 below shows the transmission power control parameters configured according to the present embodiment. Herein, for the information related to the FP, the method mentioned in the third embodiment of the present invention is applicable. The information configuration of power parameters according to the following Table 4 may also be configured in combination with one or several base stations.

Referring to Table 4, the serving base station transmits the IOT_FPx parameter and the IOT_SOUNDING parameter whose value changes in a short period (i.e., dynamically) to the terminal through an AAI-HO-CMD message, and other fixed or semi-fixed values. The remaining power control parameters whose values change may be transmitted to the terminal through an AAI-NBR-ADV message.

Seventh Example

This embodiment can configure the power control parameters for the fourth embodiment according to the present invention for the same reasons as the fifth embodiment. The power control parameter configuration according to the present embodiment may be represented as shown in Table 5 below. The information configuration of power parameters according to the following Table 5 may also be configured as a combination of one or several base stations.

In the present embodiment, the serving base station may send the AAI-NBR-ADV message including only the information related to the data channel among the power control parameters or send only the information related to the control channel. Of course, the serving base station may send both the data channel and the control channel related information to the terminal. In the sixth embodiment and the present embodiment according to the present invention, the serving base station may transmit a parameter that is dynamically changed through the AAI-HO-CMD message and also include the AAI-NBR-ADV message. In this case, the terminal may receive information included in the AAI-HO-CMD message twice. If it is received twice, it can be used by overriding with the latest information.

Eighth Example

In the above-described embodiments, the serving base station transmits the power control parameter (or power control parameter list) through the previously defined AAI-NBR-AVD message, AAI-HO-CMD message, and a new type of message. It was. However, the terminal may receive the power control parameters through a message that can be received from the base station immediately before the first uplink transmission immediately after the handover. For example, the UE may receive a power control parameter from a base station (a serving base station or a target base station) through an AAI-RNG-RSP message, an AAI-RNG-ACK message, a CDMA Allocation A-MAP IE message, or the like. However, in some cases, the first to seventh exemplary embodiments according to the present invention are not included because the above-described message may not be performed.

9th Example

As can be seen in the sixth and seventh embodiments described above, power control parameters that need to be set separately due to a short update period may be configured and used as default values. For example, the dynamically changing value IOT_FPx is transmitted by the serving base station to the UE through an AAI-HO-CMD message, and the remaining power control parameters (GAMMA_IOT_FPx, Alpha, SINRmin, SINRmax, SINR_target_HARQ, SINR_). One or more parameters among Target_SyncRanging, SINR_Target_PFBCH, SINR_Target_SFBCH_BASE, SINR_Target_SFBCH_Delta, SINR_Target_BWRequest, GAMMA_IOT_SOUNDING, SINRmin_SOUNDING, etc. may be set as default values.

Then, the processor 155 of the terminal reuses the values of some power parameters of the serving base station to determine the uplink transmission power for the first uplink transmission after the handover is completed, and the IOT_FPx value received through the AAI-HO-CMD message. Can be determined using. Equation 5 shows an equation in which the terminal calculates the NI item described in Equation 1 above.

Where P _TN represents the thermal noise power density and Δf represents the subcarrier spacing (Hz).

The terminal calculates the NI value using the IoT_FPx value received from the serving base station through the AAI-HO-CMD message, that is, the interference level (ie, IoT value) in the corresponding frequency partition, and completes the handover using the calculated NI value. Later, uplink transmission power for uplink first transmission may be determined. In addition, as shown in Equation 1, an offset value is required for a terminal to determine uplink power for uplink first transmission after handover.

In addition, as in the first embodiment, the serving base station may transmit an offset value for uplink first transmission to the terminal through the AAI-HO-CMD message after the handover of the terminal is completed. In this case, the serving base station may transmit the offset value in the form of an offsetData parameter when the first transmission of the terminal is a data channel transmission and in the form of an offsetControl parameter when the control channel is transmitted. The serving base station may transmit both the offsetData parameter and the offsetControl parameter to the terminal or may selectively transmit the terminal.

Then, the processor 155 of the terminal may determine the transmit power for the first uplink transmission after the handover is completed using the offset value received from the serving base station and the IoT value for the corresponding frequency partition. In addition, the processor 155 of the terminal receives an offset value, an IoT value, and the remaining power control parameters received from the serving base station through the AAI-HO-CMD message, using the values of the power control parameters of the serving base station as they are. The transmit power for the first link transmission can be determined.

For AAI-ULPC-NI messages, the period may be greater than other power control message periods. Therefore, there is a high possibility that the handover may not be received within an interruption time. In addition, other power control parameters may also be set to default values.

When the processor 155 of the terminal determines the transmit power for the first uplink transmission, the necessary power parameters other than the offset value and the IOT_FPx parameter may use a predetermined default value. Or, the terminal can reuse the power control parameter information of the serving base station. That is, if the terminal receives the offset value and the IOT_FPx parameter from the serving base station through the AAI-HO-CMD message, the processor 155 of the terminal uses the offset value and the IOT_FPx parameter value, the remaining power control parameter values of the serving base station By reusing the power control parameter values as they are, power for the first transmission of the uplink after the handover is completed may be determined. In addition, if the terminal receives the offset value and IOT_FPx parameter from the target base station through the CDMA Allocation A-MAP IE message after completing the ranging process for the target base station, the processor 155 of the terminal is the offset value and the IOT_FPx parameter. Using the value, the remaining power control parameters may determine power for the first uplink transmission after the handover is completed using a predetermined default value.

According to various embodiments of the present invention described above, the base station may support the terminal in the handover to determine the transmission power for uplink transmission after the handover is completed.

The embodiments described above are the components and features of the present invention are combined in a predetermined form. Each component or feature shall be considered optional unless otherwise expressly stated. Each component or feature may be implemented in a form that is not combined with other components or features. It is also possible to construct embodiments of the present invention by combining some of the elements and / or features. The order of the operations described in the embodiments of the present invention may be changed. Some configurations or features of certain embodiments may be included in other embodiments, or may be replaced with corresponding configurations or features of other embodiments. It is clear that the claims that are not expressly cited in the claims may be combined to form an embodiment or be included in a new claim by an amendment after the application.

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

Industrial availability

A terminal device for controlling uplink transmission power and a method thereof can be industrially used in various communication systems such as IEEE 802.16, 3GPP LTE, and LTE-A.

Claims (18)

In the method for controlling the uplink transmission power by the terminal in a wireless communication system,
Receiving a first message including an interference level in a frequency partition allocated to the terminal from a serving-advanced base station (S-ABS) or a target-advanced base station (T-ABS);
Determining a transmission power value for uplink signal transmission to the target-advanced base station (T-ABS) using the interference level; And
And transmitting an uplink signal to the target base station at the determined transmission power value. The method of claim 1,
The first message further includes an offset value corresponding to a power correction value for transmitting an uplink signal to the target base station.
The transmission power value is determined using the interference level and the offset value, uplink transmission power control method. The method of claim 2,
And the first message is an AAI-HO-CMD message type. The method of claim 2,
And the first message is a CDMA Allocation A-MAP IE message type. The method of claim 1,
The uplink signal transmission is a first uplink signal transmission to the target base station after handover completion, uplink transmission power control method. The method of claim 3,
The step of determining the transmit power value is further determined using the remaining power control parameters other than the interference level and the offset value, wherein the remaining power control parameters are values of the remaining power control parameters of the serving base station. Power control method. 5. The method of claim 4,
The step of determining the transmit power value is further determined using the remaining power control parameters other than the interference level and the offset value, and the value of the remaining power control parameters is a predetermined default value. Control method. The method of claim 2,
And the offset value is a power correction value for data channel transmission to the target base station. The method of claim 2,
The offset value is a power correction value for the control channel transmission to the target base station, uplink transmission power control method. A terminal device for controlling uplink transmission power in a wireless communication system,
A receiving antenna for receiving a first message including an interference level in an assigned frequency partition from a serving-advanced base station (S-ABS) or a target-advanced base station (T-ABS);
A processor for determining a transmission power value for uplink signal transmission to the target-advanced base station (T-ABS) using the interference level; And
And a transmission antenna configured to transmit an uplink signal to the target base station at the determined transmission power value. The method of claim 10,
The first message further includes an offset value corresponding to a power correction value for transmitting an uplink signal to the target base station.
The processor determines the transmission power value for the uplink signal transmission using the interference level and the offset value. 12. The method of claim 11,
The first message is an AAI-HO-CMD message type. 12. The method of claim 11,
The first message is a CDMA Allocation A-MAP IE message type. The method of claim 10,
The uplink signal transmission is a first uplink signal transmission to the target base station after handover completion. 13. The method of claim 12,
The processor further uses the remaining power control parameters other than the interference level and the offset value to determine the transmit power value, wherein the remaining power control parameters are values of the remaining power control parameters of the serving base station. . The method of claim 13,
And the processor further uses the remaining power control parameters other than the interference level and the offset value to determine the transmit power value, the value of the remaining power control parameters being a predetermined default value. 12. The method of claim 11,
And the offset value is a power correction value for data channel transmission to the target base station. 12. The method of claim 11,
And the offset value is a power correction value for control channel transmission to the target base station.

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