KR20040041289A - Apparatus and method for controlling transmission power serving multimedia broadcast/multicast service in mobile communication system - Google Patents

Abstract

PURPOSE: An apparatus and a method are provided to efficiently control the power of the channel for transmitting a multimedia broadcast/multicast service(MBMS) and reduce power consumption by permitting the radio network controller to transmit a channel measurement report to the base station. CONSTITUTION: A method comprises a step of permitting user equipment(401,402) to measure a channel quality of packet data transmitted from a base station for a preset time period, and transmit information for controlling transmitting power to a radio network controller if the measured channel quality fails to satisfy a predetermined threshold level; a step of permitting the radio network controller which has received the information for controlling transmitting power to transmit a transmitting power increase command to the base station in accordance with the information for controlling transmitting power; and a step of permitting the base station to control the transmitting power of the packet data in accordance with the transmitting power increase command.

Description

Transmission apparatus and method for transmitting multicast multimedia broadcasting service in mobile communication system {APPARATUS AND METHOD FOR CONTROLLING TRANSMISSION POWER SERVING MULTIMEDIA BROADCAST /

The present invention relates to power control of a wireless channel transmitted from a base station to a mobile terminal in a mobile communication system. In particular, the present invention relates to a radio resource for a [MBMS] multimedia broadcast multicast service (hereinafter referred to as MBMS). An apparatus and method for controlling power of a wireless channel transmitted from a base station to a user terminal to be efficiently used.

The MBMS [Wideband Code Division Multiple Access (WCDMA)] provides a multimedia service to all user equipments (hereinafter referred to as UEs) through a mobile communication system, or the present service. It may be said that the method provides the MBMS with one channel for UEs subscribed to. Therefore, the above method enables one or more UEs to share and receive a channel, thereby maximizing channel efficiency, enabling multimedia service with efficient channel use, and providing high quality service at a low fee even in billing. It is characterized by.

1 is a diagram illustrating a process of applying the MBMS to a wireless mobile communication network. Hereinafter, the MBMS will be described in detail with reference to FIG. 1. 1 shows a plurality of UEs, a base station (Node B), a radio network controller (hereinafter referred to as RNC), and a central network (hereinafter referred to as CN) for controlling or providing the MBMS. It consists of. UEs capable of receiving the MBMS are composed of UE1 101 to UE8 108, and the UEs are included in one cell of a plurality of cells. The UE1 101 to UE3 103 are included in the cell 1 111 of the plurality of cells, and the UE4 to UE5 105 are included in the cell 2 112 of the plurality of cells. The plurality of cells refers to cells in which the MBMS is supported by a base station (Node B) 121. For convenience of description, the base station is used in the same concept as the cell concept. It is apparent that the base station may manage only one cell and may manage a plurality of cells. In FIG. 1, three cells are managed. The RNC 131 receives the packet data (multimedia data) from a service packet radio service support node (hereinafter referred to as SGSN) and supports the MBMS or transmits the specific base station 121. To send. In addition, the RNC 131 controls the radio channels established between the base station 121 and the UEs 101 to 108 in order to provide the MBMS. 131), the base station 121, and the plurality of cells 111 to 113 constitute the UMTS Radio Access Network (hereinafter referred to as UTRAN), and the UTRAN serves to connect the UE and the CN.

The SGSN 141 controls the MBMS related services of each subscriber. Typical examples include managing service billing data of each subscriber and selectively transmitting multimedia data to a specific RNC. To this end, the SGSN 141 needs to know the list of the RNC 131 receiving the MBMS. The RNC 131 controls a plurality of cells and selects the MBMS among the cells managed by the SGSN 141 as a desired cell. Send service data. To this end, the SGSN 141 is connected to a Home Location Register (hereinafter referred to as HLR) 151 to perform authentication for the subscriber.

A gateway GPRS support node (hereinafter referred to as a GGSN) 161 broadcasts / multicasts a service to MBMS data to be supplied to UEs 101 to 108 supported by the MBMS. A multicast service center (hereinafter referred to as BM / SC) 181 and a border gateway (hereinafter referred to as BG) 171 to a contents provider 191 and a multicast broadcast resource unit (Multicast). The MBMS data is received from the broadcast source (192, 193) and transmitted to the SGSN (141). In addition, the GGSN 161 plays a role of management of the mobility of each UE 101 to 108 and service quality management of a serviced MBMS. The BG 171 receives MBMS data from the multicast broadcast resource unit 192 in a network not currently managed by the service provider and transmits the MBMS data to the GGSN 161. In addition, the BM-SC 181 receives MBMS data from the content supply unit 191 and delivers the MBMS data to the GGSN 161, and at the same time, authentication of the content supply unit 191, MBMS service quality determination, and MBMS data loss Error correction function, charge for content supply, and serve as MBMS announcements currently being serviced for the respective UEs 101 to 108. The content supply unit 191 and the multicast broadcast resource units 192 and 193 indicate the source of MBMS data transmission.

Therefore, as described above, the MBMS data stream is transferred from the content supply unit 191 to the GGSN 161 via the BM-SC 181. Or from the multicast broadcast resource unit 192 to the GGSN 161 via the BG 161 or directly from the broadcast multicast resource unit 193 to the GGSN 161. The GGSN 161 transfers the received MBMS data stream to each of the UEs 101 to 108 via the SGSN 141 and the RNC 131.

In order to provide any MBMS service, basic information about the MBMS service must first be delivered to UEs, and when UEs receiving basic information about the MBMS service want to receive the arbitrary MBMS service, the list of UEs is provided. Must be delivered to this network. When receiving a list of UEs that wish to receive the MBMS service in the network, the network should set up a radio bearer for providing the MBMS service by paging the UEs. After the radio bearer is established with the UEs, the MBMS service is provided through the radio bearer. On the other hand, when the MBMS service is terminated, it must be notified to all UEs, and thus, all UEs must release all resources allocated for the MBMS service so that normal MBMS service can be performed. .

The MBMS may be transmitted using a point to point (hereinafter referred to as PTP) scheme and a point to multipoint (hereinafter referred to as PTM) scheme. The PTM refers to a method of transmitting up to the end of a cell so that all UEs can receive it by using a common channel such as Cell 1 111 and Cell 3 113 of FIG. 1, and the PTP is the Cell 2 ( 112) refers to a method of configuring and transmitting a separate channel for each UE. Since the PTP transmission method basically uses an existing dedicated channel, it operates in the same manner as the conventional method. MBMS service basically uses the PTM transmission scheme.

2 shows a detailed structure of the upper layer of the UTRAN defined in 3GPP and channels between layers. The messages of the upper layer processed by the UTRAN can be largely classified into a control signal and user data. In FIG. 2, a control plane signal (hereinafter referred to as a C-Plane) signal 201 and a user plane (Hereinafter referred to as U-Plane). The C-Plane signal 201 and the U-Plane data 202 are messages of a Non Access Stratum (hereinafter referred to as NAS). The NAS messages refer to messages that are not used for a wireless connection between the UE and the UTRAN so that the UTRAN does not need to know its contents. Unlike the NAS, a message used directly for wireless connection between the UTRAN and the UE is called an access stratum (hereinafter referred to as an AS) message. The AS message indicates data or a control signal used in the radio resource control (hereinafter referred to as RRC) 211 of FIG. 2.

The RRC 211 is a physical layer (hereinafter referred to as L1) 291 related to the connection between the UE and the UTRAN 291, and medium access control (hereinafter referred to as MAC) 271, Radio Link Control (hereinafter referred to as RLC) 241, Packet Data Convergency Protocol (hereinafter referred to as PDCP) 221, Broadcast / Multicast Control (Broadcast / Multicast Control) 231) to control things related to the connection between the UE and the UTRAN. The PDCP 221 receives packet data to be transmitted from the NAS layer and transmits the packet data to the RLC 241. The BMC 231 receives data necessary for broadcasting and multicasting from the NAS layer and transmits the data to the RLC 241. The RLC 241 receives the control message transmitted from the RRC 221 to the UE and processes the RLC 241 into an appropriate form in the RLC # 1 251 and the RLC #m 252 in consideration of the characteristics of the control message. . The processed control message is transmitted to the MAC 271 using a logical channel 261. In addition, the RLC 241 receives data from the PDCP 221 and the BMC 231 and processes the data into an appropriate form in the RLC # 1 253 and the RLC #n 254. The processed data is transmitted to the MAC 271 using the logical channel 261. How many RLCs are generated in the RLC unit 241 is determined by the number of radio links between the UE and the UTRAN. In addition, the logical channel 261 is largely divided into a dedicated type channel that is a channel for a specific UE and a common type channel that is a channel for a plurality of UEs. It is also divided into control type channel and traffic type channel according to the nature of the message. Table 1 shows the types and roles of the logical channels 261.

designation role Broadcast Control Channel (BCCH) Used for downlink transmission from UTRAN to UE, and used for transmission of UTRAN system control information. Paging Control Channel (PCCH) It is used for downlink transmission from the UTRAN to the UE, and is used to transmit control information to the UE when the location of the cell to which the UE belongs is unknown. Common Control Channel (CCCH) It is used to transmit control information between the UE and the network, and is used when the UE does not have an RRC connection channel. Dedicated Control Channel (DCCH) It is used for 1: 1 control information transmission between the UE and the network, and is used when the UE has a connection with the RRC. Common Traffic Channel (CTCH) 1: Used for data transmission between the network and the UEs. Dedicated Traffic Channel (DTCH) It is used for 1: 1 data transmission between the network and the UE.

The MAC 271 manages a radio resource between the UE and the UTRAN under the control of the RRC 211 and manages a connection between the UE and the UTRAN. In addition, the MAC 271 receives the logical channels 261 from the RLC 241, maps the logical channels 261 to the Transport Channels 281, and transmits them to the L1 291. Table 2 describes the types and roles of the transport channels 281.

designation role Broadcast channel (BCH) It is mapped with the BCCH to transmit the data of the BCCH. Paging Channel (PCH) It is mapped with the PCCH to transmit the data of the PCCH. Randon Access channel (RACH) It is used for transmission from the UE to the network, and is used for transmission of network connection and control messages and short length data. Forward Access Channel (FACH) Used for transmission of control messages and data from a network to specific UEs or specific UEs. BCCH, CTCH, CCCH, DCTH, DCCH can be mapped. Dedicated Channel (DCH) Channel that can transmit data and control signal between network and UE, DTCH and DCCh are mapped Downlink Shared Channel (DSCH) DTCH and DCCH are mapped to the downlink channel from the network to the UE used for transmission of high capacity data High Speed DSCH (HS-DSCH) DTCH and DCCH are mapped to the downlink channel from the network which improves the efficiency of the transmission capability of the DSCH to the UE.

The transport channels 281 transmitted to the L1 291 are transmitted to the UE or the UTRAN after corresponding processes to corresponding physical channels. The physical channels are referred to as a primary common control channel (hereinafter referred to as P-CCPCH) for transmitting the BCH, and a secondary common control physical channel (hereinafter referred to as P-CCPCH) for transmitting the PCH and FACH. S-CCPCH.), Dedicated Physical Channel (hereinafter referred to as DPCH) for transmitting the DCH, and Physical Downlink Shared Channel (hereinafter referred to as PDSCH) for transmitting the DSCH. , A High Speed Physical Downlink Shared Channel (HS-PDSCH) for transmitting the HS-DSCH, and a Physical Random Access Channel (hereinafter referred to as PRACH) for transmitting the RACH. Pilot channel, which is a pure physical channel that does not transmit higher layer data or control signals other than the channels, and a first synchronization channel. Synchronization Channel, Secondary Synchronization Channel, Secondary Synchronization Channel, Paging Indicator Channel, Paging Indicator Channel, Acquisition Indicator Channel, Physical Common Packet Channel.

In 3GPP, there are various methods for supporting the MBMS, but it can be classified into two types. The two distinctions are based on the relationship between the UE and the UTRAN and are divided into a connected mode and an idle mode according to the relationship between the UE and the UTRAN. The connected mode refers to a state in which the RRC 211 can exchange control signaling or data with a specific UE as described in FIG. 2, and the RRC 211 knows information about the UE and an RRC connection diagram. It is. The idle mode is a case in which the RRC 211 does not know that a specific UE exists and there is no method in which the RRC 211 and the specific UE can exchange control signaling or data.

The method of receiving MBMS when the UE is in the connected mode and the method of receiving MBMS when in the idle mode have advantages and disadvantages. When the MBMS is supported in the connected mode, the UE has information about the UE. Therefore, although signaling and control for the UE is simple, since the RRC connection for the MBMS is required, a lot of resources of the UTRAN must be used. When the MBMS is supported in the idle mode, signaling and control of the UE becomes difficult because there is no information on the UE, but since RRC connection for the MBMS is not necessary, resources of the UTRAN may be spared.

3 is a diagram illustrating a case where a power control method is not used for an MBMS. Hereinafter, a problem that may occur when the power control method is not used in the MBMS will be described with reference to FIG. 3. For convenience of description of the present invention, in FIG. 3, the MBMS is transmitted using the PTM method, and a downlink channel for the MBMS uses a control channel and a data channel for the MBMS. In addition, it is assumed that a common channel such as the RACH described in Table 2 is used as the uplink channel. 3 illustrates only a part of the parts illustrated in FIG. 1, the remainder is the same as that of FIG. 1.

3 illustrates a problem in particular in terms of power waste when transmitting MBMS data without applying power control. As described above, the PTM method is a method in which UEs receiving one MBMS receive the MBMS using one common channel. Accordingly, as shown in FIG. 3, the common channel transmitting the MBMS should be transmitted to the cell boundary regardless of the positions of the UEs 331 to 335 receiving the MBMS. Hereinafter, the RNC 301 receives the MBMS from the CN and transmits the MBMS to the base station 311. Cell 1 321 includes three UEs 331 to 333, and among the three UEs 331 to 333, UE1 331 and UE2 332 are located near the center of Cell 1 321. The UE3 333 is located near the cell boundary of the cell 1 321. Accordingly, the cell 1 321 does not have a problem regarding waste of power even when the common channel transmitting the MBMS is transmitted to the cell boundary.

The cell 2 322 includes a UE4 334 and a UE5 335, in which case the UE4 334 to the UE5 335 are located at the center of the cell 2 322 and the cell 2 ( There is no UE located at the boundary of 322. Such a case may occur when the UE located at the cell boundary moves to another cell. The UE4 334 and the UE5 335 receiving the MBMS service of the Cell 2 322 receive the UEMS 334 to the UE5 335 at a greater power than the required reception power in receiving the MBMS. . Accordingly, the cell 2 322 transmits the MBMS data using an unnecessarily large transmission power in transmitting the MBMS. In addition, the unnecessary large transmission power serves as an interference signal, that is, a noise source, to UEs existing in other cells that do not receive the MBMS from the Cell 2 322. In addition, other cells adjacent to the cell 2 322 also act as an unnecessary noise source.

As such, excessively large transmission power in transmitting MBMS data causes unnecessary noise to other UEs and cells, and power is wasted.

Accordingly, an object of the present invention for solving the above problems is to provide an apparatus and method for power control for a channel for transmitting MBMS in a mobile communication system.

Another object of the present invention is to provide an apparatus and method for controlling the power, and to provide an apparatus and method for transmitting a power control command to a base station managing a channel through which a wireless network controller transmits the MBMS.

Another object of the present invention is to provide an apparatus and method for reducing unnecessary message transmission and uplink interference caused by the message transmission by not reporting unnecessary channel measurement information to the wireless network controller.

In order to solve the above object of the present invention, the RNC receives radio environment channel measurement information from one or more user terminals that receive a channel for transmitting the MBMS data, thereby receiving the radio environment channel measurement information from the MBMS. The present invention provides an apparatus and method for efficiently controlling power of a channel for transmitting the MBMS by informing a base station managing a channel for transmitting the MBMS.

In order to solve the object of the present invention, the RNC receives radio environment channel measurement information from one or more user terminals receiving the channel for transmitting the MBMS data, and transmits the radio environment channel measurement information to the MBMS. Inform the base station managing the channel. In this case, when the base station has already transmitted the MBMS data to the user terminal at the maximum power, the base station transmits a maximum power notification message to the RNC, and the received RNC transmits the radio environment channel measurement information to the user terminal for a predetermined period. The present invention provides an apparatus and method for efficiently controlling power of a channel for transmitting the MBMS by transmitting an interrupting report stop message.

In order to solve the object of the present invention, by setting the radio stop bearer between the RNC and the user terminal and the base station, by setting the report stop period, the report valid period, the S-CCPCH power compensation value, etc. by the user terminal during the report valid period The present invention provides an apparatus and method for reducing and transmitting unnecessary control signaling in the MBMS power control by measuring and reporting the MBMS power value, and not reporting the received MBMS power value during the report suspension period.

1 is a diagram illustrating an example of a 3GPP mobile communication network for MBMS.

2 is a diagram illustrating a radio access network protocol structure in a 3GPP mobile communication network.

3 is a diagram illustrating a problem when a power control method is not used in a conventional MBMS.

4 is a diagram illustrating an example of signaling for a power control method presented in the present invention.

FIG. 5 illustrates a problem when applying the method of FIG. 4. FIG.

6 is a view showing another power control method proposed in the present invention to solve the problem of FIG.

FIG. 7 is a diagram illustrating a control flow in the user terminal illustrated in FIG. 6.

8 is a diagram illustrating a control flow in the base station shown in FIG.

9 is a diagram illustrating a control flow of the wireless network controller shown in FIG. 6.

10 is a view showing another power control method proposed in the present invention to solve the problem of FIG.

FIG. 11 is a diagram illustrating a control flow in the user terminal illustrated in FIG. 10.

FIG. 12 illustrates a control flow at the base station shown in FIG. 10. FIG.

FIG. 13 is a diagram illustrating a control flow of the wireless network controller shown in FIG. 10.

Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings. It should be noted that in the following description, only parts necessary for understanding the operation according to the present invention will be described, and descriptions of other parts will be omitted so as not to distract from the gist of the present invention.

FIG. 4 is an embodiment for providing a power control method for a channel for transmitting MBMS data in order to reduce unnecessary power waste of MBMS transmission described with reference to FIG. As described above, in FIG. 3, the base station always transmits data to a cell boundary using a power of a predetermined size or more using the common data channel. However, FIG. 4 shows that the RNC supports the MBMS with the amount of power required by each UE by using channel measurement information (Measurement Report) for the MBMS channel received from each UE. Hereinafter, this will be described in detail with reference to FIG. 4.

Although FIG. 4 shows N UEs, a description will be given of UE # 1 401 and UE # N 402 for convenience of description. In addition, it is obvious that the UE # 1 401 and the UE # N 402 are UEs receiving MBMS data. The controlling RNC (hereinafter referred to as CRNC) 421 is a radio bearer for performing step 431 on the UE # 1 401 and the UE # N 402 to support the MBMS. (Hereinafter, referred to as RB). In this case, the RB configuration may use the downlink shared channel described in Tables 1 and 2 or an MBMS dedicated control channel. In FIG. 4, the procedure before the MBMS RB setup procedure of 431 is omitted in the procedure for MBMS. After the RB setting is performed, the CRNC 421 transmits a signal to interference ratio for the MBMS data to the UE # 1 401 and the UE # N 402 through the set RB. Transmits a value for SIR). The target SIR value is set to a minimum value for the UEs to receive the MBMS data with sufficient power. When transmission of the RB setting and the SIR value is completed from the CRNC 421 to the UE # 1 401 and the UE # N 402, the CRNC 421 transmits the MBMS data to the base station 411. The base station 411 receives the MBMS data and transmits the data to the UEs 401 and 402.

Steps 441 to 443 show a process in which the base station 411 transmits the MBMS data received from the CRNC 421 to the UEs 401 and 402. In this case, the MBMS data transmission from the base station 411 to the UEs 401 and 402 uses a downlink shared channel or an MBMS data dedicated channel.

The UE # 1 401 to the UE # N 402 measure the power of the MBMS data transmission channel (also referred to as channel quality information) received in steps 441 to 443 in step 451 to measure the measured channel. The information is reported to the CRNC 421. The channel measurement information refers to a difference between an objective SIR value received from the CRNC 421 and an SIR value for the MBMS data in step 431. In other words, the channel quality information means an SIR value for the received MBMS data. In addition, in order to transmit the channel measurement information to the CRNC 421, the UE # 1 401 to the UE # N 402 transmit the RRC message. To this end, the target SIR value and the measured SIR value are transmitted from the L1 to the RRC. In this case, the UE # 1 401 to the UE # N 402 do not report the channel measurement information for every received MBMS data through the uplink channel, but rather to the downlink shared channel or the channel for MBMS data for a set period. The channel measurement information is reported to the uplink channel only when the received received power is insufficient. By doing so, the interference signal generated when the channel measurement information is reported through the uplink channel for each received MBMS data is prevented from being increased.

The UE # 1 401 to the UE # N 402 measure and compare the target SIR value with the SIR value for the received MBMS data. In order to measure the SIR value for the received MBMS data, a pilot signal of S-CCPCH is used. In this case, the UEs may increase the difference value between the target SIR and the measured SIR by the CRNC, or may only upload information on an increase or decrease request from the base station.

In FIG. 4, for the data transmitted in steps 441 to 442 among the MBMS data transmitted by the base station 411, the UE # 1 401 to UE # N 402 have the strength of the received power measured by the channel. It is shown that the channel measurement information is not reported to the CRNC 421 because it is sufficient. If the channel measurement report is not received from the UE # 1 401 to the UE # N 402, the CRNC 421 does not report any channel measurement information to the base station 411. If the base station 411 does not receive any channel measurement information from the CRNC 421 for a predetermined period of time, the base station 411 reduces the previously transmitted MBMS transmission power by a predetermined predetermined size and then transmits the MBMS data at a reduced power. do. In more detail, since no channel measurement report is raised for a certain period of time, the current MBMS data transmission power is sufficient. Therefore, by reducing the transmission power to some extent, the MBMS data can be efficiently used. will be. This is caused by the UE # 1 401 to UE # N 402 transmitting the data to enable the base station 411 to receive the MBMS data using transmit power greater than the required power strength. This is to reduce unnecessary waste of power.

However, the UE # 1 401 shows that the channel measurement information is transmitted to the CRNC 421 in step 451 with respect to the MBMS data transmitted in step 443. This is because the strength of the received power measured by the UE # 1 401 is not sufficient, and thus reports channel measurement information, which is information about this, to the CRNC 421. The CRNC 421 reports the transmission power control information determined from the channel measurement information to the base station 411 based on the channel measurement information received from the UE # 1 401 in step 461. After receiving the transmission power control information determined from the channel measurement report reported from the CRNC 421, the base station 411 includes the transmission power control information determined from the channel measurement information to the UE # 1 401 in step 444. The transmission power is set by referring to the difference between the measured SIR value and the target SIR value, and the MBMS data is transmitted at the newly set transmission power.

In this case, the transmission power control information determined from the channel measurement information sent by the CRNC 421 to the base station 411 may be an increase or decrease of the transmission power, or may be an increase or decrease command of the transmission power. Although not shown in FIG. 4, if two or more UEs present in the same cell receiving MBMS data report the channel measurement information to the CRNC 421, the CRNC 421 indicates the purpose of the reported channel measurement information. The channel measurement information (channel measurement information with poor channel environment) having the largest difference between the SIR value and the measured SIR value is selected to report the selected channel measurement information to the base station 411. In this case, the CRNC may inform the base station 411 of the channel measurement information received from the UEs as a difference between a target SIR and a measured SIR, and determine the increase or decrease of power from the channel measurement information to the base station 411. In this case, information about how much to increase or decrease power may be provided. Of course, this may vary depending on the implementation method.

As described above, when the base station 411 does not receive the channel measurement information from the CRNC 421, the MBMS data transmission power is reduced by the set size, but the base station 411 reports the channel measurement information from the CRNC 421. When receiving, the MBMS data transmission power is set to a power strength that satisfies the reported channel measurement information, not increasing the MBMS data transmission power by the set size.

FIG. 5 illustrates a problem that may appear when the power control method of FIG. 4 is applied to the MBMS. UE # 1 501, UE # 2 502, UE # M 503, and UE # N 504 represent UEs receiving MBMS data included in the same cell. In addition, as shown in FIG. 5, the UE # 1 501, the UE # 2 502, and the UE # M 503 transmit the MBMS data even when the BS 511 transmits the MBMS maximum transmission power. Represents UEs that cannot receive MBMS data. The reason why the specific UE or UEs do not receive the MBMS service even with the base station maximum transmission power may occur because the UE # 1 501, the UE # 2 502, and the UE # M 503 are cell boundary lines. Or due to deterioration of the channel environment. This will be described with reference to FIG. 5.

The base station 511 transmits the MBMS data to the UE # 1 501, the UE # 2 502, the UE # M 503, and the UE # N 504 at the maximum MBMS transmission power set in step 531. . The UE # 1 501, the UE # 2 502, the UE # M 503, and the UE # N 504 that have received the MBMS data have the target SIR value set to themselves as described above with reference to FIG. 4. The SIR of the measured MBMS data is measured and compared. As a result of the comparison, the UE # N 504 does not report the channel measurement information to the CRNC 521 because the received and measured SIR value is higher than the set value. However, the UE # 1 501, the UE # 2 502, and the UE # M 503 receive and measure the SIR value smaller than the set target SIR value, that is, the received power is insufficient. 521) reports the channel measurement information, that is, the difference between the target SIR and the measured SIR. The UE # 1 501 reports channel measurement information about the MBMS data received in step 531 to the CRNC 521 in step 541, and the UE # 2 502 receives the received channel information in step 531. In operation 542, the channel information about the MBMS data is reported to the CRNC 521. In addition, the UE # M 503 reports channel measurement information on the MBMS data received in step 531 to the CRNC 521 in step 543. The CRNC 521, which has received the channel measurement information from the UE # 1 501, the UE # 2 502, and the UE # M 503, has channel measurement information having the worst channel environment among the reported channel measurement information. The base station 511 selects the largest value among the difference between the target SIR and the measured SIR.

The base station 511 receiving the power control information determined from the channel measurement information from the CRNC 521 should transmit MBMS data at a power increased by the size required by the power control information determined from the channel measurement information. However, if the base station 511 is already transmitting MBMS data at its maximum MBMS transmit power, the MBMS data transmit power at step 532 can be transmitted at the same maximum MBMS transmit power as at step 531. There is nothing else. As described above, the UE # 1 501, the UE # 2 502, the UE # M 503, and the UE # N 504, which have received the MBMS data transmitted by the base station 511 in step 532. The measured SIR of the received MBMS data signal is compared with the set target SIR. Since the UE # N 504 satisfies the quality of the MBMS data reception channel when the MBMS data is received with a better SIR than the target SIR, the UE does not transmit the channel measurement information to the CRNC 521. When the measured SIR of the received MBMS data does not reach the target SIR, the UE # 1 501, the UE # 2 502, and the UE # M 503 perform steps 544 through 544, similar to steps 541 to 543. Perform step 546. That is, the UE # 1 501 reports channel measurement information on the MBMS data received in step 532 to the CRNC 521 in step 544, and the UE # 2 502 performs step 532. In step 545, the channel information about the MBMS data received in step 5 reports the channel measurement information to the CRNC 521. In addition, the UE # M 503 reports the channel measurement information on the MBMS data received in step 532 to the CRNC 521 in step 546. The CRNC 521 selects channel measurement information having the poorest channel environment among the channel measurement information reported from the UE # 1 501, the UE # 2 502, and the UE # M 503, and selects the base station ( 511). In this case, the RNC may select information having the largest difference between the target SIR and the measured SIR, that is, the channel state having the worst, and send a difference between the values of the target SIR and the measured SIR to the base station or according to the difference. You can decide if there should be an increase or decrease of the power, and ask for the increase or decrease of the power, and send the information of the increase or decrease of the power.

As such, even though the base station 511 transmits the MBMS data at the maximum power, the CRNC 521 repeatedly receives the channel measurement information to the base station 511 because the UEs receive insufficient transmission power. Send it. However, when the base station 521 is already transmitting the MBMS data at the maximum power, it is no longer possible to increase the power transmitted to the UE. As described above, when the base station 511 is using the maximum MBMS transmission power, the UE # 1 501, the UE # 2 502, and the UE # M 503 repeatedly repeat unnecessary channel measurement information each time. 521).

In the above situation, although the UEs 501, 502, 503 having insufficient reception power cannot obtain satisfactory reception power even by reporting channel measurement information, the base station 511 transmits at the maximum MBMS transmission power. Because it does not know, it periodically reports channel measurement information. The repetitive reporting of channel measurement information not only wastes the transmission power of the UEs 501, 502, 503 but also interferes with the uplink channels transmitted by other UEs in the cell in which the UEs 501, 502, 503 are located, That is, it acts as a noise source and also acts as an unnecessary noise source for other cells adjacent to the cell. In particular, the UE # 1 501, the UE # 2 502, and the UE # M 503 move upward when the base station 511 does not receive the MBMS data even when the base station 511 transmits MBMS data at the maximum MBMS transmission power. It requires a large transmit power to report channel measurements on the channel and operates as a large interference signal.

In order to solve the MBMS problem shown in FIG. 3, the present invention has proposed an MBMS power control method using channel measurement information. However, as shown in FIG. 5, it can be seen that there is a problem of unnecessary transmission of an uplink channel signal. In order to solve such a problem, more efficient MBMS data solving the problem of the present invention in FIGS. A transmission power control method is proposed.

FIG. 6 defines a new message for controlling transmission power of MBMS data to solve the problem shown in FIG. 5, thereby preventing interference of an uplink channel due to reporting of channel measurement information shown in FIG. 5. An efficient MBMS power control method is shown in a timing diagram.

The UE # 1 601, the UE # 2 602, the UE # M 603, and the UE # N 604 illustrated in FIG. 6 represent UEs receiving the MBMS service, and the UE # 1 601, UE # 2 602, and UE # M 603 are the same as the base station 611 in the same manner as the UE # 1 501, the UE # 2 502, and the UE # M 503 of FIG. 5. UEs that do not receive the MBMS data even though the MBMS data are transmitted with the set maximum MBMS transmission power strength. Hereinafter will be described in detail with respect to FIG.

The base station transmits the MBMS data to the UE # 1 601, the UE # 2 602, the UE # M 603, and the UE # N 604 at the set maximum MBMS transmission power in step 631. The UE # 1 601, the UE # 2 602, the UE # M 603, and the UE # N 604 that have received the MBMS data have a target SIR value set to themselves as described above with reference to FIG. 4. Compare the measured SIR values for the received MBMS data. As a result of the comparison, the UE # N 604 does not report the channel measurement information to the CRNC 621 because the received SIR value is higher than the set target SIR value. However, since the UE # 1 601, the UE # 2 602, and the UE # M 603 have received and measured SIR values smaller than the set target SIR values, that is, the received power is insufficient, the CRNC Report channel measurement information to 621. That is, since the quality of the currently received MBMS data does not guarantee the quality as much as the set target SIR, this is to request an increase in the transmission power of the MBMS data currently transmitted to the base station. In this case, as described above, the difference between the target SIR and the measured SIR may be reported as in the exemplary embodiment of the present invention, or the power increase request may be simply performed. Of course, this can be modified depending on the implementation. The UE # 1 601, the UE # 2 602, and the UE # M 603 transmit channel measurement information about MBMS data received in step 631 in step 641, step 642, and step 643. Report channel measurement information. The CRNC 621, which has received the channel measurement information from the UE # 1 601, the UE # 2 602, and the UE # M 603, reports channel measurement information having the worst channel environment among the reported channel measurement information. Select to report to the base station 611 in step 651.

The base station 611 notified of the channel measurement information from the CRNC 621 must increase MBMS transmission power based on the reported channel measurement information as described in FIG. 5. However, since the maximum MBMS transmission power is already used, the power cannot be increased any more as described above. Accordingly, the base station 611 transmits MBMS data at maximum power to the UE # 1 601, the UE # 2 602, the UE # M 603, and the UE # N 604 at step 652. The CRNC 621 notifies the MAX Power Indication message. The maximum power notification message indicates that the base station is already transmitting the MBMS data to the UEs at full power. The CRNC 621 informs the CRNC 621 that the base station 611 is using the maximum MBMS transmit power through the maximum power notification message, so that the CRNC 621 receives the UE # 1 601, the UE # 2 602, and the UE. The timing of reducing the channel measurement report using the up channel of #M 603 may be known.

In step 632, the base station 611 maintains the maximum MBMS transmission power in the same manner as in step 631 and stores the MBMS data in UE # 1 601, UE # 2 602, UE # M 603, and UE # N ( 604). As described above, the UE # 1 601, the UE # 2 602, the UE # M 603, and the UE # N 604 that have received the MBMS data transmitted by the base station 611 are described above. The SIR of the received MBMS data is compared with the preset target SIR value. The UE # N 604 does not transmit the channel measurement information to the CRNC 621 because the data of the channel quality higher than the set target SIR is received, but the UE # 1 601, the UE # 2 602, and the UE do not transmit the channel measurement information. Since the #M 603 receives MBMS data of the same channel quality as the set target SIR, the same operation as the steps 641 to 643 is repeated. That is, the UE # 1 601 reports channel measurement information on the MBMS data received in step 632 to the CRNC 621 in step 644. Although not shown in the drawing, the UE # 2 602 and the UE # M 603 also report channel measurement information about the MBMS data received in step 632 to the CRNC 621. The CRNC 621 may receive and report the channel measurement information from the UE # 1 601, the UE # 2 602, the UE # M 603, and the UE # N 604. (Hereinafter, referred to as a report validity period) can be set. The period may be set by the CRNC 621 to any value in consideration of the channel environment. The UE # 1 601, the UE # 2 602, the UE # M 603, and the UE immediately after the CRNC 621 receives the maximum power notification message in step 521 by setting the report validity period. By not stopping the channel measurement report from #N 604, this is to consider UEs that temporarily do not have sufficient reception power of the MBMS data when the base station 611 transmits at the maximum MBMS transmit power. Accordingly, during the report valid period, the UE # 1 601, the UE # 2 602, the UE # M 603, and the UE # N 604 transmit the channel measurement information on the received MBMS data to the CRNC 621. You can report it as

If channel measurement information from the UE # 1 601, the UE # 2 602, the UE # M 603, and the UE # N 604 is not reported to the CRNC 621 during the report valid period, the UE Indicates that they are receiving MBMS data of sufficient quality. In this case, the CRNC 621 does not report any channel measurement information to the base station 611. Accordingly, the base station 611 reduces the MBMS data transmission power and resets the reporting validity period. However, if the channel measurement information is continuously notified to the CRNC 621 from one or more of the UEs 601 to 604 until the reporting validity period ends, the CRNC 621 expires at the same time as the reporting validity period expires. In step 661, the base station 611 transmits a maximum power hold request message (MAX Power Hold Request). The base station 611 which has received the maximum power hold request message from the CRNC 621 notifies the CRNC 621 of the maximum power hold response message (MAX Power Hold Response) in step 662. In addition, the CRNC 621 that is notified of the MAX Power Hold Response message from the base station transmits the UE # 1 601, the UE # 2 602, the UE # M 603, A report stop message (Measurement Report Stop) is transmitted to the UE # Ns 604.

After the base station 611 transmits the maximum power maintenance response message to the CRNC 662, the UE # 1 601 and the UE # 2 602 transmit the MBMS data at the maximum power in steps 633 to 634. , UE # M 603 and UE # N 604. The base station 611 transmits the UE # 1 601, the UE # 2 602, and the UE at the maximum MBMS transmit power until a maximum power release request message is received from the CRNC 621. The MBMS data is transmitted to #M 603 and UE # N 604. In this case, the UE # 1 (601), the UE # 2 (602), the UE # M (603), and the UE # N (604) that are notified of the report stop message receiving MBMS data from the base station 611 report. The channel measurement information is not reported to the CRNC 621 until a measurement report stop is received. That is, the UE # 1 601, the UE # 2 602, the UE # M 603, and the UE # N 604 that receive the report stop message in step 671 receive the MBMS data during the report stop period. Even if the reception power of the transmission channel is insufficient, channel measurement information is not reported to the CRNC 621.

The CRNC 621 transmits a maximum power release request message to the base station 611 by the CRNC 621 at the request of the CRNC 621, and maintains the maximum power transmitted in step 661. Demands the release of In response to receiving the maximum power release request message, the base station 611 transmits a maximum power release response message to the CRNC 621 in step 682. In addition, unlike the above, it is apparent that the CRNC 621 may include the information on the maximum power maintenance period in the maximum power maintenance request message performed in step 661 to the base station 611. By including the information on the maximum power maintenance period, the base station 611 may allow the maximum MBMS transmission power to be used during the maximum power maintenance period. In addition, in the above-described method of using the maximum power holding period information, the base station 611 automatically releases the maximum power holding request notified in step 661 when the transmitted maximum power holding period expires.

The CRNC 621 that has received the maximum power release request response message in step 682 may transmit the UE # 1 601, the UE # 2 602, the UE # M 603, and the UE # N 604 in step 691. Send a start message. The UE # 1 601, the UE # 2 602, the UE # M 603, and the UE # N 604 that have received the report start message receive the MBMS data transmitted from the base station 611. Channel measurement information may be reported to the CRNC 621. Unlike the above, the CRNC 621 performs the report stop message performed in step 671 with the UE # 1 601, the UE # 2 602, the UE # M 603, and the UE # N 604. Obviously, it is possible to include information on the report suspension period therein. By including the information on the reporting period, the UE # 1 601, the UE # 2 602, the UE # M 603, and the UE # N 604 receive the channel measurement information during the reporting period. It may not transmit to the CRNC 621. In addition, the method of using the above-described report suspension period information may be generated by the UE # 1 601, the UE # 2 602, the UE # M 603, and the UE # N 604 by the error of the start report of step 691. Even if the transmission is not normally performed, the report suspension request notified in step 671 is automatically released when the reporting suspension period set to the transmission expires.

Table 3 below describes the names and roles of newly defined messages used in the present invention of FIG. 6. Although not shown in Table 3, information on the target SIR value is transmitted from the CRNC to the UEs through the common control channel for the MBMS, the downlink shared channel, etc. when the MBMS radio bearer is set up.

designation role Channel Measurement Information The CRNC selects and reports the worst channel information among channel measurement information received from UEs receiving MBMS to the base station. MAX Power Indication The base station informs the CRNC that it is currently using the maximum MBMS transmit power. MAX Power Hold Request Message The CRNC continues to request the base station to use the maximum MBMS transmit power until it sends a maximum power release request message (which can be used with the maximum power hold period information). MAX Power Hold Response Message The base station notifies the CRNC of the maximum power maintenance request message sent by the CRNC. MAX Power Release Request Message The CRNC releases the maximum MBMS transmit power usage request from the maximum power maintenance request message to the base station. Max Power Release Response Message The base station notifies the CRNC of the maximum power release request message sent by the CRNC. Measurement Report Stop Do not report channel measurement information until the base station receives the report start message to the UEs receiving the MBMS. Measurement Report Start Allow the CRNC to report channel measurement information back to the UEs receiving the MBMS.

7 is a diagram illustrating an operation flow of a UE for receiving MBMS data according to the present invention of FIG. 6. As shown in FIG. 6, the RB setting process is omitted in FIG. 7. In step 701, the UE receives the MBMS data from the base station. Upon receiving the MBMS data transmitted from the base station, the UE measures the received MBMS data power (ie, SIR) in step 702. After measuring the power (SIR) of the MBMS data, the UE checks whether the MBMS power measurement period notified by the CRNC has expired in step 703. If the power measurement period has expired as a result of the test, the process moves to step 711. If the power measurement period has not expired, the process moves to step 701 to receive the next MBMS data.

After the power measurement period expires and the UE moves to step 711, the UE determines whether the most recently received message from the CRNC is a report stop message. The message notified from the CRNC to the UE includes the report stop message and a report start message. In this case, if the most recently received message from the CRNC is a report stop message, the UE moves to step 701, in which the UE waits for a report start message after receiving the report stop message from the CRNC. It means that there is. Therefore, in the reporting suspension period, even if the UE has insufficient MBMS data reception power, the UE goes to 701 without receiving channel measurement information and receives the next MBMS data.

If the most recently received message from the CRNC is a report start message or if no message is received, it means that the base station does not use the maximum MBMS transmit power or the UE is within the report valid period. According to the MBMS power control method according to the present invention, if the SIR value of the MBMS data received in step 721 is equal to or greater than the predetermined target SIR value, the UE returns to step 701 to receive the next MBMS data. However, if the SIR value of the MBMS data received from the base station in step 721 is smaller than the preset target SIR value, go to step 731 to report channel measurement information to the CRNC, and then go to step 701 to obtain the next MBMS data. Receive.

8 is a diagram illustrating an operation flow in a base station transmitting MBMS data according to the present invention of FIG. 6. In FIG. 8, as in FIG. 7, the MBMS procedure is omitted until the RB is set between the CRNC and the UE supported by the MBMS. Hereinafter, the operation of the base station for transmitting the MBMS data will be described with reference to FIG. 8.

The base station sets the initial MBMS transmission power to transmit the MBMS data received from the CRNC in step 801 after the RB for transmitting to the MBMS data UE is set. The initial MBMS transmit power may be arbitrarily set by the user or by the command of the CRNC. In general, however, transmission is based on the maximum power that the base station can transmit. When the initial MBMS transmission power is set, the base station transmits MBMS data received from the CRNC to UEs supporting the MBMS in step 802. At the same time, the base station checks in step 803 whether the transmission power transmitting the MBMS data is the maximum in step 802. If the base station does not transmit the MBMS data at the current maximum transmission power as a result of the check, the method proceeds to step 812. Reducing the up-interference signal of the UE for receiving the operation.

First, the base station does not transmit the MBMS data at the maximum transmit power in step 802. If the MBMS data is not transmitted at the maximum transmission power, the base station determines whether channel measurement information is received from the CRNC in step 812. As described above, the channel measurement information informs the base station of the information notified to the UEs by the CRNC. The base station for receiving the channel measurement information from the CRNC moves to step 861. If the channel measurement information is not received from the CRNC, the base station moves to step 862. The base station shifted to step 861 is transmitting the MBMS data at a transmission power insufficient for the UEs to transmit the MBMS data. Accordingly, after resetting the MBMS transmission power so that the UEs can receive the MBMS data with sufficient quality by using the channel measurement information notified from the CRNC, the mobile station proceeds to step 802 to transmit MBMS data to the UEs. . In addition, the base station, which has moved to step 862, resets to reduce the MBMS transmission power by a predetermined size since the UEs are already transmitting the MBMS data with sufficient power. In this way, the waste of MBMS transmission power can be prevented. The base station reconfigured to decrease the MBMS transmission power moves to step 802 to transmit the MBMS data to the UEs with the reduced MBMS transmission power.

When the base station is currently transmitting the MBMS data at the maximum MBMS transmission power, the base station checks whether channel measurement information is received from the CRNC in step 811 as in step 812. If the channel measurement information is received as a result of the check, go to step 821, and if the channel measurement information is not received, go to step 822. When the channel measurement information is received from the CRNC, the base station moves to step 821 to notify the CRNC that the MBMS data is already transmitted to the UEs at the maximum transmission power. This is carried in the maximum power notification message as shown in FIG. After transmitting the maximum power notification message to the CRNC, the base station moves to step 841 to maintain the maximum MBMS transmit power currently being transmitted, and then moves to step 802 to transmit the MBMS data to the UEs.

If the channel measurement information is not received from the CRNC, the base station determines whether a maximum power maintenance request message is received from the CRNC in step 822. The maximum power maintenance request message is a message that the base station requests the UEs to transmit the MBMS data at maximum power until a power maximum release request message is received. If the base station receives the maximum power maintenance request message from the CRNC, the mobile station proceeds to step 831, and if the base station does not receive the maximum power maintenance request message from the CRNC, it proceeds to step 832. When the base station receives the maximum power maintenance request message in step 822, the base station transmits a maximum power maintenance response message, which is a response to the maximum power maintenance request message, to the CRNC in step 831. After transmitting the maximum power maintenance response message, the base station moves to step 841 to maintain the MBMS transmission power at the maximum power, and then moves to step 802 to transmit the MBMS data to the UEs.

If the maximum power maintenance request message is not received in step 822, the base station determines whether the maximum power release request message is received from the CRNC in step 832. The maximum power release request message is a message for requesting the base station to stop transmitting the MBMS data at the maximum MBMS transmit power regardless of whether or not channel measurement information is received from the CRNC by the maximum power maintenance request message. If the maximum power release request message is not received from the CRNC, the base station moves to step 862. If the maximum power release request message is received from the CRNC, the base station moves to step 851. The base station may reduce the MBMS transmission power by a predetermined amount if the channel measurement information is not received from the CRNC until after receiving the maximum power release request message from the CRNC until the next maximum power maintenance request message is received. . In step 851, the base station transmits a maximum power release response message, which is a response to the maximum power release request message, to the CRNC. In step 841, the base station maintains the MBMS transmission power at the maximum power. The base station, which has not received any message from the CRNC, proceeds to step 862 to reduce the MBMS transmission power by the predetermined predetermined size, and then moves to step 802 to transmit MBMS data to the UEs. .

FIG. 9 is a diagram illustrating an operation flow of a CRNC according to the present invention of FIG. 6. After the CRNC transmits MBMS data to the base station, the CRNC waits at step 901 whether channel measurement information for the transmitted MBMS data is received from UEs, and then moves to step 902. In step 902, the base station determines whether the preset channel measurement information reporting period has expired. If it is determined that the channel measurement information reporting period has not expired, the CRNC moves to step 901 and waits for reporting of the channel measurement information from the UEs. If the channel measurement information reporting period has expired as a result of the determination, the CRNC moves to step 911. The CRNC moving to step 911 determines whether channel measurement information is reported from the UEs during the channel measurement information reporting period. If the channel measurement information is reported as the determination result, the CRNC moves to step 921. In addition, if the channel measurement information is not reported as the determination result, the CRNC moves to step 912. Hereinafter, first, a case in which channel measurement information is not reported from the UEs during the channel measurement information reporting period will be described.

In step 912, the CRNC determines whether the last message sent to the UEs is a report stop message. This is to determine whether the channel measurement information does not exist in step 911 because the UEs satisfy the reception power of the MBMS data received from the base station or because the UEs are in the reporting stop period. to be. If the last message sent to the UEs in step 912 is a report stop message, the CRNC moves on to step 971. If the last message sent to the UEs is not a report stop message, the CRNC moves to step 901. Wait for channel measurement information to be received. The CRNC moving to step 971 determines whether the report suspension period has expired. If the report suspension period has expired as a result of the determination, the CRNC moves to step 981. If the report suspension period has not expired, the CRNC moves to step 901 to wait for reception of channel measurement information from the UEs. The CRNC, which has moved to step 981, transmits a maximum power release request message to the base station because the report suspension period has expired. The base station receiving the maximum power release request message transmits a maximum power release response message, which is a response thereto, to the CRNC, and the CRNC determines whether the maximum power release response message is received in step 991. If the maximum power release response message is not received from the base station as a result of the determination, the process proceeds to step 981 and newly transmits the maximum power release request message. However, regardless of whether the maximum power release response message is received, a predetermined time may be set, and when the set time elapses, the maximum power release request message may be newly transmitted to the base station. If the maximum power release response message is received from the base station as a result of the determination, the process moves to step 992 and transmits a report start message to the UEs. The UEs having received the report start message may report channel measurement information to the CRNC when the received power of the received MBMS data is insufficient. That is, the process moves to step 901 and waits for receiving the channel measurement information from the UEs.

If the channel measurement information exists in step 911, the CRNC transmits the channel measurement information to the base station in step 921. Although not shown in FIG. 9, when the plurality of channel measurement information is received by a plurality of UEs, the CRNC selects the channel measurement information having the poorest channel environment among the received channel measurement information and transmits the channel measurement information to the base station. In this case, the RNC may select information having the largest difference between the target SIR and the measured SIR, that is, the channel state having the worst, and send a difference between the values of the target SIR and the measured SIR to the base station or according to the difference. You can decide if there should be an increase or decrease of the power, and ask for the increase or decrease of the power, and send the information of the increase or decrease of the power. The CRNC, which has transmitted the channel measurement information to the base station in step 921, determines whether a maximum power notification message is received from the base station in step 922. The maximum power notification message is a message indicating that the base station is already transmitting the MBMS data to the UEs at the maximum power. If the maximum power notification message is not received from the base station as a result of the determination, the CRNC moves to step 901 and waits for receiving the channel measurement information from the UEs. The reporting validity period is temporary when the base station uses the maximum MBMS transmit power by not interrupting reporting of channel measurement information from the UEs even after the CRNC receives the maximum power notification message from the base station as described above. This is to consider the UEs that do not receive MBMS data.

In step 922, the CRNC that receives the maximum power notification message from the base station determines whether the report validity period has expired. If the report validity period has not expired as a result of the determination, the CRNC moves to step 901 and waits for receiving the channel measurement information from the UEs.

If the determination result reporting validity period in step 931 expires, the CRNC moves to step 941 and transmits a maximum power maintenance request message to the base station. The base station receiving the maximum power maintenance request message transmits a maximum power maintenance response message, which is a response thereto, to the CRNC, and the CRNC determines whether the maximum power maintenance response message is received in step 951. If the maximum power maintenance response message is not received from the base station as a result of the determination, the process proceeds to step 941 and newly transmits the maximum power maintenance request message. However, regardless of whether the maximum power maintenance response message is received, a predetermined time may be set, and when the set time has elapsed, the maximum power maintenance request message may be newly transmitted to the base station. If the maximum power maintenance response message is received from the base station as a result of the determination, the process moves to step 961 and transmits a report stop message to the UEs. The UEs that receive the report stop message receive channel measurement information when the received power of the received MBMS data is insufficient (that is, when the SIR value of the received MBMS data is smaller than the preset target SIR value). You cannot report it. The CRNC, which has sent a report stop message to the UEs, moves to step 901 and waits for receiving the channel measurement information from the UEs.

FIG. 10 is a diagram illustrating another embodiment of power control when transmitting MBMS data from a base station. In FIG. 10, UEs and the base station transmit information on the MBMS power control when the RB is set up for MBMS data transmission. The UE and the base station operate according to the information on the transmitted MBMS power control, and thus, an efficient power control method for preventing interference of an uplink channel according to channel measurement information reporting of the UEs is illustrated. In addition, in FIG. 6, the CRNC is controlled by a control signal in which the CRNC transmits the number of reports of channel measurement information to UEs receiving the MBMS data. In FIG. 10, the UE receives the MBMS power control information. Controlled by Hereinafter, the present invention will be described in detail with reference to FIG. 10.

The UE # 1 1000, the UE # 2 1002, the UE # M 1003, and the UE # N 1004 of FIG. 10 represent UEs supported by the MBMS to the base station 1011, of which the The UE # 1 1000, the UE # 2 1002, and the UE # M 1003 may not receive the MBMS data sufficiently even when the base station 1011 transmits the MBMS data at the maximum MBMS transmission power. Indicates.

The CRNC 1021 instructs the base station 1011 to set MBMS RB for the MBMS data transmission in step 1031. The MBMS RB setting command includes information on the MBMS power control, and the information on the MBMS power control includes information of a maximum MBMS power strength, a report valid period, and a report stop period.

In addition, the CRNC 1021 sets MBMS RB for the MBMS data transmission to the UE # 1 1000, the UE # 2 1002, the UE # M 1003, and the UE # N 1004 in step 1041. Order. The MBMS RB setting command includes information on the MBMS power control, and the information on the MBMS power control includes information of a maximum MBMS power offset, a report valid period, and a report stop period. The maximum MBMS maximum power offset indicates an offset with respect to a power value of a first common pilot channel (hereinafter, referred to as a P-CPICH), and the strength of the P-CPICH is represented by a system information block. Block: (hereinafter referred to as SIB)), through the maximum MBMS power offset, UEs 1000 to 1004 can know the strength of the maximum power used for the MBMS. In addition, the UEs may compare the information on the transmit power of the P-CPICH received with the SIB with the measured P-CPICH power to obtain an offset value between the received power and the transmit power, and the UEs may determine the offset value. The MBMS transmit power value at the base station can be known by adding the measured received power value of the MBMS channel. The UEs 1000 to 1004 compare the value of the MBMS transmit power at the base station 1011 obtained by the method with the strength of the maximum MBMS transmit power obtained as the maximum MBMS power offset. As a result of the comparison, the UEs may check whether the received MBMS data is transmitted from the base station 1011 at the maximum MBMS transmission power. The report validity period and the report suspension period are as described above.

In step 1051, the base station 1011 transmits the MBMS data transmitted by the CRNC 1021 to the UEs 1000 to 1004 supported by the MBMS. In addition, the power for the MBMS data transmission is in principle a maximum transmission power. Upon receiving the MBMS data, the UEs 1000 to 1004 measure power of a channel transmitted from the base station 1011, that is, measure an SIR value of a channel transmitted from the base station 1011 to the base station. The strength of the MBMS transmission power is obtained at 1011 and then compared with the strength of the maximum MBMS transmission power obtained by the maximum MBMS offset, in step 1051, since the base station 1011 uses the maximum MBMS transmission power. The strength of the MBMS transmission power obtained from the measurement result obtained by the base station 1011 and the maximum MBMS transmission power obtained by the maximum MBMS offset are the same. The MBMS data is transmitted using the maximum MBMS transmission power. From this time, the UEs 1000 to 1004 are notified of the notification in step 1041. The reporting validity period starts .. As a result of the comparison, the UE # N 1004 does not notify the CRNC 1021 of any signal since the received power value of the transmitted channel is greater than or equal to a certain size. ), The UE # 2 1002 and the UE # M 1003 compare the MBMS data by the base station 1011 using the maximum transmission power, and at the same time, the reception power of the transmitted MBMS data is insufficient. This can be determined by comparing the measured SIR value of the received MBMS data with the target SIR value, and the channel measurement information means a difference between the measured SIR value and the target SIR value. If the UE # 1 (1000), the UE # 2 (1002), the UE # M (1003) is found to start the report valid period performed in step 1021 and accordingly the UE # 1 (1000), UE # 2 (1002), UE # M (1003) is the channel side to the CRNC 1021 And inform. That is, the UE # 1 1001 reports channel measurement information regarding the MBMS data received in step 1051 to the CRNC 1021 in step 1061, and the UE # 2 1002 reports the step 1051. In step 1062, the channel information about the MBMS data received by the UE reports channel measurement information to the CRNC 1021. In addition, the UE # M 1003 reports channel measurement information on the MBMS data received in step 1051 to the CRNC 1021 in step 1063. The reporting of the channel measurement information is performed until the report validity period set in step 1031 ends. The CRNC 1021, which has received the channel measurement information from the UE # 1 1001, the UE # 2 1002, and the UE # M 1003, measures a channel having the worst channel environment among the reported channel measurement information. Information is selected and reported to the base station 1011 in step 1071. In addition, when the transmission power of the transmitted MBMS data is less than the maximum MBMS transmission power from the base station 1011 during the reporting validity period, the UEs exit the reporting validity period and are shown in FIG. 4. The power control method according to the invention is used. However, when the base station 1011 transmits the MBMS data at the maximum MBMS transmission power during the report valid period, the UEs start the report suspension period set in step 1021. That is, it can be seen that the report suspension period starts from the step before 1052 in FIG. 10.

In steps 1052 to 1053, the base station 1011 transmits the MBMS data received from the CRNC 1021 to the UE # 1 1000, the UE # 2 1002, the UE # M 1003, and the UE # N. Transmit to (1004). However, the UEs 1000 to 1004 that have received the MBMS data received in steps 1052 to 1053 do not notify the CRNC 1021 of the channel measurement information even if the power of the received MBMS data is insufficient. This is because the UEs 1000 to 1004 are included in the report suspension period in this step. However, since step 1053 is performed, the report suspension period ends, the UEs 1000 to 1004 measure power of a transmission channel with respect to the MBMS data transmission performed in step 1054. If the measured channel power is insufficient, the UE # 1 1001 reports the channel measurement information to the CRNC 1021 in step 1064. Accordingly, the base station 1011 may adjust the MBMS transmission power according to whether the channel measurement information from the CRNC 1021 is reported within the report valid period using the information of the report valid period and the report suspension period. MBMS data is transmitted while maintaining the maximum MBMS transmission power within the report suspension period.

FIG. 11 is a diagram illustrating an operation flow in a UE receiving MBMS data according to the present invention of FIG. 10. Hereinafter, the operation of the UE will be described in detail with reference to FIG. 11. In step 1101, the UE receives a command for setting MBMS RB for MBMS data transmission from the CRNC. The MBMS RB setting command includes information on the MBMS power control, and the information on the MBMS power control includes information of a maximum MBMS power offset, a report valid period, and a report stop period. The information on the MBMS power control transmitted to the UE is transmitted through a MBMS dedicated common control channel or through a downlink shared channel such as FACH. When the MBMS RB configuration is completed in step 1101, the UE moves to step 1102 to determine whether the MBMS data is transmitted from the base station and receives it. In step 1103, the UE measures the transmission power of the transmission channel of the MBMS data received in step 1102 and then moves to step 1104. The transmission power value of the base station is obtained by adding the offset values of the reception power and the transmission power that can be obtained through the P-CPICH to the reception power value measured by the UE. The UE that has moved to step 1104 is set to determine whether a channel report validity period has expired. If the channel report validity period has expired as a result of the determination, go to step 1111; if the channel report validity period has not expired, go to step 1102 to receive the MBMS data.

In step 1111, the UE determines whether the reception power of the transmission channel of the MBMS data received in step 1103 is transmitted at the maximum transmission power value. This is done by comparing the maximum MBMS transmit power value obtained using the maximum MBMS power offset set in step 1101. If the base station transmits at the maximum MBMS transmission power as a result of the determination, the UE moves to step 1122. If the base station does not transmit at the maximum MBMS transmission power, the UE moves to step 1121. In step 1121, the UE determines whether the received power for the transmission channel of the MBMS data is insufficient. If the determination result is insufficient, the UE moves to step 1131 to transmit the channel measurement information to the CRNC. Go to step 1102. Insufficient received power for the MBMS data may be determined by comparing the target SIR value shown in FIG. 4 with the measured SIR value, and the channel measurement information is a difference value between the target SIR value and the measured SIR value. Is self-explanatory. If the UE, which has moved to step 1121, has sufficient reception power on the transmission channel of the MBMS data, the UE moves to step 1102 without notifying any information to the CRNC.

If the transmission power of the MBMS data transmitted by the base station in step 1111 is the maximum MBMS transmission power value, the UE determines whether the current report valid period is in step 122. If the determination result is the current report valid period, the UE moves to step 1121 and determines whether the received power for the received MBMS data is insufficient. In addition, if the determination result in step 1122 is not the current report valid period, it means that the current report is suspended. Therefore, during the report suspension period, the UE moves to step 1102 without receiving channel measurement information regardless of the reception power of the MBMS data received by the CRNC and receives the MBMS data.

12 is a diagram illustrating an operation flow in a base station for transmitting MBMS data according to the present invention of FIG. Hereinafter, an operation of a base station transmitting MBMS data will be described with reference to FIG. 12.

In step 1201, the base station receives a command for setting MBMS RB for MBMS data transmission from the CRNC. The MBMS RB setting command includes information on the MBMS power control, and the information on the MBMS power control includes information on a maximum MBMS transmit power strength, a report valid period, and a report stop period. In step 1202, the base station sets transmission power for the MBMS data to be transmitted to the UE. In principle, the transmission power is determined as the maximum transmission power. After determining the transmission power to be transmitted to the UE in step 1202, the base station transmits the MBMS data received from the CRNC to the UE that supports the MBMS data in step 1203, and then moves to step 1204 to transmit the transmitted MBMS data. It is determined whether the transmission is at the maximum transmission power. If the transmission results in the maximum transmission power as a result of the determination, the operation proceeds to step 1211. Hereinafter, the case of moving to step 1212 will be described first.

In step 1212, the base station determines whether the channel measurement information is received from the CRNC. If the channel measurement information is received as a result of the determination, the base station moves to step 1241 and analyzes the channel measurement information. After resetting the MBMS transmission power sufficient for the UE to receive the MBMS data by the analysis, go to step 1203 to transmit the MBMS data. If the channel measurement information is not received from the CRNC in step 1212, the base station reduces the MBMS transmission power by a predetermined size since the UEs are receiving the MBMS data with a sufficient size.

In step 1211, the base station determines whether channel measurement information is received from the CRNC in the same manner as in step 1212. If the channel measurement information is received from the CRNC as a result of the determination, the flow proceeds to step 1221. If the channel measurement information is not received from the CRNC, the flow moves to step 1222. The base station moved to step 1221 maintains the maximum MBMS transmit power transmitted in step 1202 and then moves to step 1203. The base station which has moved to step 1222 determines whether the current reporting stop period. This is because the Node B did not receive the channel measurement information from UEs receiving MBMS to distinguish whether the UEs are all receiving MBMS data with sufficient reception power or whether the UEs are included in the reporting pause period. . If the determination result of step 1222 is the current report suspension period, the process moves to step 1221 to maintain the MBMS transmission power at the maximum power. If the determination result is not the current report suspension period, the operation proceeds to step 1231 to set the MBMS transmission power. After reducing by the size, the process moves to step 1203.

FIG. 13 is a diagram illustrating an operation flow of a CRNC according to the present invention of FIG. 10. Hereinafter, the operation of the CRNC will be described with reference to FIG. 13. The CRNC instructs the base station to set the MBMS RB for the MBMS data transmission in step 1301. The MBMS RB setting command includes information on the MBMS power control, and the information on the MBMS power control includes information of a maximum MBMS transmit power strength, a report valid period, and a report stop period. In addition, the CRNC instructs the UE to set MBMS RB for the MBMS data transmission in step 1302. The MBMS RB setting command includes information on the MBMS power control, and the information on the MBMS power control includes information of a maximum MBMS power offset, a report valid period, and a report stop period. The CRNC performing the steps 1301 to 1302 waits for receiving channel measurement information from UEs supporting the MBMS data in step 1303. In step 1304, the CRNC determines whether the measurement report period has expired. If the channel measurement report period has expired as a result of the determination, the process moves to step 1311. If the channel measurement information report period has not expired, the process moves to step 1303 and waits for receiving channel measurement information from the UE. In step 1311, the base station determines whether there is channel measurement information received from the UEs. If no information exists, the base station moves to step 1303 and waits for receiving channel measurement information from the UE. However, if there is received channel measurement information, the CRNC transmits the channel measurement information to the base station. If there is a plurality of received channel measurement information, the CRNC selects and reports the channel measurement information having the worst channel condition to the base station. The worst of the channel measurement information is the channel specific information having a largest difference between the target SIR value and the measured SIR value received from the UEs.

Accordingly, the RNC receives radio environment channel measurement information from one or more user terminals receiving the MBMS, and informs the base station transmitting the channel of the MBMS of the radio environment channel measurement information to the base station transmitting the MBMS. Power control of the channel to transmit the power can be efficiently controlled, thereby avoiding unnecessary waste of power. In addition, by not transmitting the channel measurement information transmitted from the UEs for a predetermined period of time under a predetermined condition, it is possible to reduce an uplink interference signal generated by transmitting the channel measurement information. In addition, when the base station receives the channel measurement information and then adjusts the transmission power, the method of raising the transmission power as much as desired by the UE as well as the method of raising the predetermined value of the channel measurement information transmitted on the uplink by presenting The amount can be reduced.

Claims (42)

A base station that provides a packet data service to user terminals and controls a transmission power of packet data transmitted from the base station to the user terminals in a mobile communication system that controls the transmission power of the base station by a wireless network controller. In the method, The user terminals measure channel quality information of the packet data transmitted from the base station for a set time, and when the measured channel quality information does not satisfy a predetermined threshold, transmits information for controlling the transmission power to a wireless network controller. Process, Receiving, by the wireless network controller, the information for controlling the transmit power, transmitting the increase or decrease of the transmit power or the increase or decrease command of the transmit power to the base station based on the information for controlling the transmit power; And the base station controls the transmission power of the packet data according to the received increase or decrease of the transmit power or the increase or decrease command of the transmit power. The method as claimed in claim 1, wherein the channel measurement information is a difference between a signal-to-noise ratio of the preset reference value and the received packet data. The wireless network controller which has received the plurality of channel measurement information from the user terminals, transmits the channel measurement information having the worst channel condition among the received channel measurement information to the base station. The method. The method of claim 1, further comprising the step of the base station reducing the transmission power of the packet data by a predetermined amount if there is no channel measurement information received for a predetermined time. The method of claim 1, further comprising: notifying the wireless network controller that the packet data is being transmitted at the maximum transmission power when the base station transmitting the packet data at the maximum transmission power receives the channel measurement information. The method characterized in that. 6. The base station of claim 5, wherein the base station if the wireless network controller notified that the packet data is being transmitted at full power continues to receive channel measurement information from the user terminal until the channel measurement information report validity period ends. And notifying to maintain the maximum transmission power of the packet data. 7. The process as claimed in claim 6, further comprising the step of being informed by the base station notified to maintain the maximum transmission power of the packet data to the radio network controller. 8. The method as claimed in claim 7, further comprising the step of notifying the user terminal to stop reporting the channel measurement information by the wireless network controller receiving the maximum power maintenance response. The method of claim 8, wherein the user terminals notified of the stop of reporting the channel measurement information further include stopping the transmission of the channel measurement information to the radio network controller until the radio network controller is notified of the start of the channel measurement information report. The method characterized in that. 7. The method of claim 6, wherein the base station notified by the radio network controller of maintaining maximum transmission power of packet data includes transmitting the packet data at maximum power until a maximum power release request message is received. Characterized in that the method. The method as claimed in claim 10, wherein the radio network controller transmits a maximum power release request message to the base station when the channel measurement information report suspension period expires. The method as claimed in claim 11, wherein the base station receiving the maximum power release request message transmits a maximum power release response message to the wireless network controller. The method as claimed in claim 12, wherein the wireless network controller which has received the maximum power release message notifies the user terminals of channel measurement information report. 10. The method of claim 8, wherein the channel measurement information report stop message further includes information on the report suspension period, and further includes automatically releasing the report suspension request when the report suspension period expires at a user terminal. Characterized in that the method. A base station that provides a packet data service to user terminals and controls a transmission power of packet data transmitted from the base station to the user terminals in a mobile communication system that controls the transmission power of the base station by a wireless network controller. In the method, Transmitting a maximum transmit power strength, a report valid period, and a report stop period of a packet data service when a radio bearer is set up from the radio network controller to the base station; Transmitting the maximum power offset of the packet data service, the report validity period and the report suspension period when the radio bearer is set up from the base station to the user terminal; After the packet data transmission, the wireless network controller which has received the information for transmission power control from the user terminals sends the base station an increase / decrease or decrease command of the transmission power by the information for controlling the transmission power. Sending process, And the base station controls the transmission power of the packet data according to the received increase / decrease of the transmission power or the increase / decrease command of the transmission power. A base station that provides a packet data service to user terminals and controls a transmission power of packet data transmitted from the base station to the user terminals in a mobile communication system that controls the transmission power of the base station by a wireless network controller. In the method, Receiving, by the user terminal, a maximum power offset of the packet data service, the report valid period, and the report stop period when the radio bearer is set up from the radio network controller; The user terminals receiving the information about the report validity period and the report suspension period measure channel quality information of packet data transmitted from the base station for a set time, and the measured channel quality information does not satisfy a predetermined threshold. Transmitting the information for controlling the transmission power to a wireless network controller; Determining that the base station is transmitting at the maximum transmission power of the data packet by using the maximum power offset of the packet data service received by the user terminal and the strength of the common channel of the packet data; Transmitting the channel measurement information only during the received report validity period when the user terminal needs to transmit the channel measurement information when the base station is transmitting data at the maximum transmission power; When the user terminal continuously transmits the channel measurement information during the received report validity period, transmitting the channel measurement information to the stopped state during the received report suspension period after the report valid period expires; And after the reporting stop period has expired, allowing the user terminal to transmit channel measurement information. 17. The method of claim 15 or 16, wherein the channel measurement information is a difference between a signal-to-noise ratio of the preset reference value and the received packet data. 17. The method of claim 15 or 16, further comprising: obtaining maximum packet data transmit power using the strength information of the transmit power of the common channel received by the SIB and the maximum transmit power offset received by the user terminals; Comparing the transmit power information of the common channel received by the SIB with the transmit power of the shared channel transmitted by the base station to obtain an offset between the received power and the transmit power; Obtaining the packet data transmission power of the base station by adding the offset to the received power of the packet data. The method as claimed in claim 15 or 16, wherein the maximum transmit power is obtained by adding up the maximum packet power offset and the received packet power received from the wireless network controller. The method as claimed in claim 15 or 16, wherein the wireless network controller which has received the plurality of channel measurement information from the user terminals transmits the channel measurement information having the worst channel condition to the base station. The method as claimed in claim 15 or 16, further comprising a step of reducing the transmission power of the packet data by a predetermined amount if the channel measurement information is not received through the radio network controller. A base station that provides a packet data service to user terminals and controls a transmission power of packet data transmitted from the base station to the user terminals in a mobile communication system that controls the transmission power of the base station by a wireless network controller. In the apparatus, The user terminal for measuring the channel quality information of the packet data transmitted from the base station for a set time, and transmits the information for controlling the transmission power to the wireless network controller when the measured channel quality information does not meet a predetermined threshold value Field, A wireless network controller transmitting an increase or decrease of the transmit power or an increase or decrease command of the transmit power to the base station by the received information for controlling the received transmit power; The base station for controlling the transmission power of the fraudulent packet data according to the increase or decrease of the received transmission power or the command for increasing or decreasing the transmission power. 23. The apparatus of claim 22, wherein the channel measurement information is a difference between a signal-to-noise ratio of the preset reference value and the received packet data. The method of claim 22, wherein the wireless network controller, And when the plurality of pieces of channel measurement information are received from the user terminals, channel measurement information having the poorest channel state among the received channel measurement information is transmitted to the base station. The method of claim 22, wherein the base station, And if the channel measurement information is not received during the predetermined time, the transmission power of the packet data is reduced by a predetermined amount and transmitted. The method of claim 22, wherein the base station, And transmits the packet data at the maximum transmission power, and notifies the radio network controller that the packet data is transmitted at the maximum transmission power when the channel measurement information is received. The wireless network controller of claim 26, If it is notified that the packet data is being transmitted at full power and continuously receives channel measurement information from the user terminal until the channel measurement information reporting validity period ends, the transmission power of the packet data is maintained to the base station to the maximum. The apparatus further comprises the step of notifying. The method of claim 27, wherein the base station, And when notified to maintain the maximum transmission power of the packet data, notifying the wireless network controller of the maximum power retention response to the notification. The method of claim 28, wherein the wireless network controller, And receiving the maximum power maintenance response, notifying the user terminal of the stop of reporting the channel measurement information. The method of claim 29, wherein the user terminal, And receiving transmission of the channel measurement information to the radio network controller until the radio network controller is notified of the start of the channel measurement information report. The method of claim 27, wherein the base station, And when notified by the wireless network controller to keep the transmission power of the packet data at maximum, transmitting the packet data at maximum power until a maximum power release request message is received. 32. The wireless network controller of claim 31, And transmitting a maximum power release request message to the base station when the channel measurement information report stop period expires. The method of claim 32, wherein the base station, And receiving the maximum power release request message, transmitting a maximum power release response message to the wireless network controller. The method of claim 33, wherein the wireless network controller, Receiving the maximum power release message, notifying the user terminal of channel measurement information report. The method of claim 29, wherein the user terminal, The apparatus as claimed in claim 1, further comprising information on the report suspension period in the channel measurement information report suspension message, when the report suspension period expires. A base station that provides a packet data service to user terminals and controls a transmission power of packet data transmitted from the base station to the user terminals in a mobile communication system that controls the transmission power of the base station by a wireless network controller. In the apparatus, Transmitting the maximum transmission power strength, the report valid period, and the report stop period of the packet data service when the radio bearer is set up to the base station, and transmits the information by controlling the transmission power received from the user terminals after the packet data transmission. The radio network controller transmitting an increase or decrease of power or an increase or decrease command of the transmission power; The maximum power offset of the packet data service and the report valid period and the report stop period are transmitted to the user terminal when the radio bearer is set up, and according to the increase / decrease of the transmit power received from the radio network controller or the increase / decrease command of the transmit power. And the base station for controlling the transmission power of the packet data. A base station that provides a packet data service to user terminals and controls a transmission power of packet data transmitted from the base station to the user terminals in a mobile communication system that controls the transmission power of the base station by a wireless network controller. In the apparatus, When the radio bearer is set up from the base station, the maximum power offset of the packet data service, the report valid period, and the report stop period are transmitted, and channel quality information of the packet data transmitted from the base station is measured for a set time, and the measured channel When the quality information does not satisfy a predetermined threshold, the information for the transmission power control is transmitted to a wireless network controller. The base station determines that the base station is transmitting at the maximum transmission power of the data packet by using the received maximum power offset of the packet data service and the strength of the shared channel of the packet data, and the base station transmits data at the maximum transmission power. When the channel measurement information is to be transmitted when there is, the channel measurement information is transmitted only for the validity period of the received report. In the case where the channel measurement information is continuously transmitted during the received report validity period, the channel measurement information is stopped during the report suspension period received after the report validity period expires. And the channel measurement information can be transmitted after the reporting stop period expires. 38. The apparatus of claim 36 or 37, wherein the channel measurement information is a difference between a signal-to-noise ratio of the preset reference value and the received packet data. 38. The apparatus of claim 36 or 37, wherein the user terminals The maximum transmit power of the packet data is obtained by using the strength information of the transmit power of the shared channel received through the SIB and the maximum transmit power offset received, and the transmit power information of the shared channel received by the SIB and transmitted by the base station And comparing the transmission power of the common channel to obtain an offset between the reception power and the transmission power, and adding the offset to the reception power of the packet data to obtain the packet data transmission power of the base station. The method of claim 36 or 37, wherein the user terminals, And the maximum transmission power is obtained by adding up the maximum packet power offset received from the wireless network controller and the reception power of the packet data. 38. The method of claim 36 or 37, wherein the wireless network controller, And receiving the plurality of channel measurement information from the user terminals to transmit the channel measurement information having the worst channel condition to the base station. The method of claim 36 or 37, wherein the base station, And if the channel measurement information is not received during the predetermined time, the transmission power of the packet data is reduced by a predetermined amount and transmitted.