KR100842613B1 - Apparatus for controlling transmission power of high speed shared control channel in time division duplexing code division multiple access communication system using high speed downlink packet access scheme and method thereof - Google Patents

Abstract

A method of controlling transmit power of a common control channel in a time division duplexing code division multiple access mobile communication system using a high speed forward packet access method, the user terminal receiving a common control channel signal and receiving the received common control channel signal Generating and transmitting a measurement report for adjusting a transmission power of the mobile station to a base station; and receiving, by the base station, the measurement report from a user terminal, and adjusting the transmission power of the common control channel using the received measurement report. It includes the process of doing. Accordingly, the present invention enables high-speed transmit power control for the common control channel and improves system performance by performing the measurement report using minimal transmission resources.

HSDPA, TDD, HS-SCCH

Description

Apparatus and method for controlling high speed common control channel transmission power in time division duplexing code division multiple access communication system using high speed forward packet access method USING HIGH SPEED DOWNLINK PACKET ACCESS SCHEME AND METHOD THEREOF}             

1 is a view schematically showing the structure of a general mobile communication system

2 is a flowchart illustrating a transmission power control process according to a general fast power control method.

3 is a diagram illustrating a fast common information channel structure of a 1.28 Mcps time division duplexing code division multiple access communication system using a fast forward packet access scheme;

4 illustrates a fast common information channel structure of a 3.84 Mcps time division duplexing code division multiple access communication system using a fast forward packet access scheme;

5 is a flowchart illustrating a fast common control channel transmit power control process according to an embodiment of the present invention.

6 illustrates a structure of a fast common information channel transmitter for performing a function in an embodiment of the present invention.                 

7 illustrates a structure of a fast common information channel receiver for performing a function in an embodiment of the present invention.

The present invention relates to a mobile communication system, and more particularly, to an apparatus and method for controlling a transmission power of a fast common control channel in a time division duplexing code division multiple access mobile communication system using a fast forward packet access scheme.

As the mobile telecommunication system has developed rapidly and the amount of data serviced by the mobile communication system has rapidly increased, a third generation mobile communication system has been developed for transmitting data at a higher speed. This third generation mobile communication system uses W-CDMA (Wideband Code Division Multiple Access), which is asynchronous between base stations in Europe, and CDMA-2000 (Multiple Carrier Code Division Multiple Access), which is synchronized between base stations in North America. It is standardizing. The W-CDMA scheme is divided into a frequency division duplexing (FDD) scheme for performing communication by separating a transmission frequency band and a reception frequency band, and a transmission frequency band and a reception frequency. Two methods are used, namely, Time Division Duplexing (TDD), which uses the same band and performs communication by separating time. In addition, the TDD scheme uses a broadband time division duplexing scheme (hereinafter referred to as "WB-TDD") scheme using a chip rate of 3.84 Mcps (second chips) and a chip rate of 1.28 Mcps. Narrowband time division duplexing (hereinafter referred to as "NB-TDD") scheme.

In addition, in the W-CDMA communication system, a forward high speed packet access (HSDPA) method is introduced to provide a high speed packet service. In general, the HSDPA scheme is referred to as a high speed downlink shared channel (HS-DSCH), which is a forward data channel for supporting forward high speed packet data transmission in a W-CDMA communication system. Data transmission scheme including the control channel and the associated control channels.To support the HSDPA scheme, an adaptive modulation and coding scheme (hereinafter referred to as "AMC") and a hybrid retransmission scheme (Hybrid) Automatic Retransmission Request: (hereinafter referred to as "HARQ") and Fast Cell Selection (FCS: Fast Cell Selection, hereinafter referred to as "FCS") have been proposed.

First, the AMC scheme will be described first.

The AMC determines the modulation method and the coding method of the data channel according to the channel state between the cell and the user, thereby increasing the utilization efficiency of the entire cell. The combination of the modulation scheme and the coding scheme is called a modulation and coding scheme (MCS) and may define a plurality of MCSs from level 1 to level n. The AMC refers to a method of adaptively determining the level of the MCS according to a channel state between a user and a cell, thereby increasing the overall use efficiency.

Second, the HARQ scheme will be described.

The HARQ scheme, that is, the n-channel Stop And Wait Hybrid Automatic Retransmission Request (n-channel SAW HARQ) scheme, will be described below. In the conventional ARQ scheme, an acknowledgment signal (ACK) and a retransmission packet are exchanged between a user terminal and a base station controller (RNC: Radio Resource Controller (hereinafter referred to as "RNC")). lost. However, in the HSDPA scheme, the ACK and the retransmission packet are exchanged between the medium access control (MAC) of the user terminal and the base station Node B (hereinafter referred to as "MAC") HS-DSCH. Also, by configuring n logical channels, it is possible to transmit several packets without receiving ACK. In the conventional Stop and Wait ARQ scheme, the next packet can be transmitted only after receiving the ACK of the previous packet. This method has a disadvantage in that it is possible to wait for an ACK despite being able to transmit a packet. In n-channel SAW HARQ, a plurality of packets can be continuously transmitted without receiving an ACK, thereby improving channel utilization efficiency. If n logical channels are set between the user terminal and the base station, and the channels are identified by a specific time or explicit channel number, the receiving user terminal knows which channel the packet received at any point in time is. And reconstruct packets in the order in which they must be received.                         

Third, the FCS scheme will be described.

When the user terminal using the HSDPA enters the soft handover region, the packet is transmitted only from the cell maintaining the best channel state to reduce the overall interference. In addition, when the cell providing the best channel condition is changed, the packet is transmitted using the HS-DSCH of the cell, and the transmission disconnection time is reduced as much as possible.

The structure of the W-CDMA mobile communication system will now be described with reference to FIG.

1 is a diagram schematically illustrating a structure of a general mobile communication system.

Referring to FIG. 1, the W-CDMA mobile communication system includes a core network (CN) 100 and a plurality of radio network subsystems (RNS). 110 and 120, and a user terminal (UE: User Equipment, hereinafter referred to as "UE") (130). The RNS 110 and the RNS 120 are composed of a radio network controller (RNC: hereinafter referred to as "RNC") and a plurality of base stations (Node Bs). For example, the RNS 110 includes the RNC 111, the base station 113, and the base station 115, and the RNS 120 includes the RNC 112, the base station 114, and the base station 116. do. The RNC is classified into a Serving RNC (hereinafter referred to as "SRNC"), a Drift RNC (hereinafter referred to as "DRNC"), or a Controlling RNC (hereinafter referred to as "CRNC") according to its operation. The SRNC refers to an RNC that manages information of each UEs and is also responsible for data transmission with the CN 100. The DRNC indicates that when data of a UE is transmitted / received to an SRNC through another RNC other than the SRNC. Become another RNC. The CRNC is an RNC that controls each of the base stations. In FIG. 1, when the RNC 111 manages information of the UE 130, the RNC 111 operates as an SRNC for the UE 130, and the UE 130 moves to the UE 130. ) Data is transmitted and received through the RNC 112, the RNC 112 becomes a DRNC for the UE 130, and the RNC 111 controlling the base station 113 communicating with the UE 130. ) Becomes the CRNC of the base station 113.

Next, the channels used for transmitting actual user data in the mobile communication system using the HSDPA scheme will be described.

First, the types of channels used in the HSDPA communication stem are divided into a downlink (DL) channel and an uplink (UL) channel as follows. The forward channel includes a High Speed-Shared Control Channel (HS-SCCH) (hereinafter referred to as "HS-SCCH"), an associated Dedicated Physical Channel (DPCH), hereinafter "associated". DPCH "), and High Speed-Physical Downlink Shared Channel (HS-PDSCH), hereinafter referred to as " HS-PDSCH ". Physical channels (Secondary DPCH, hereinafter referred to as "Secondary DPCH"), high-speed common information channel (HS-SICH: High-Speed Shared Information CHannel, hereinafter referred to as "HS-SICH") and the like.

Next, a transmission power control method of the HS-SCCH among the channels will be described.

First, the transmission power control method is an open loop power control method, a closed loop power control method, a power control method such as an outer loop power control method, and the like. There are many forms such as: Next, each of the power control schemes, that is, the open loop power control scheme, the closed loop power control scheme, and the outer loop power control scheme will be described.

First, the open loop power control scheme will be described below.

First, the UE measures propagation loss for a specific channel, for example, a primary common control physical channel (P-CCPCH) signal, received from a base station receiving a service, and measured By adjusting the UE's own reverse transmission power appropriately with respect to path loss, the BS can correctly receive channel signals transmitted backward by the UE.

Here, the first common control physical channel is a channel for transmitting information of the base station and system information (SI) to the UEs in the base station. The first common control physical channel signal is always transmitted at a constant transmission power, and the magnitude of the transmission power of the first common control physical channel signal is broadcast to UEs in the base station. Therefore, the UE can measure the transmission path loss from the base station to the UE using the transmission power of the broadcasted first common control channel physical channel signal. Thus, a target signal to interference ratio (SIR) is initially determined using the open loop power control scheme.

Secondly, the closed loop power control scheme will be described.

First, the UE receives a channel signal received from a base station, and measures the magnitude of the received channel signal, that is, a signal to interference ratio (SIR), hereinafter referred to as "SIR" from the base station. If the magnitude of the received channel signal is less than a preset size, i.e., a target signal-to-interference ratio (target SIR, hereinafter referred to as "target SIR"), the transmission power control (TPC: Transmit) to increase the transmission power to the base station. Power Control, hereinafter referred to as "TPC") transmits a command. On the contrary, when the size of the signal received from the base station is greater than or equal to the set size, the TPC command is transmitted to the base station to lower the transmission power. Then, the base station adjusts the forward transmission power so that the transmission power of the channel signal received by the UE can have a constant level according to the TPC command received from the UE, which is a closed loop power control scheme.

Third, the outer loop power control scheme will be described.

First, the closed loop power control method described above is a method of performing power control based on a target signal to interference ratio. However, a criterion for evaluating the quality of a wireless channel signal in an actual mobile communication system is a bit error rate (BER) or a block error rate (BLER: BLock) rather than the signal-to-interference ratio. Error Rate, hereinafter referred to as "BER"). Here, the BER or BLER represents an error rate limit of the digital signal required for providing good voice quality, and has a great correlation with the communication satisfaction of the user who uses the communication. Thus, a target bit error rate (target BER, hereinafter referred to as a "target BER") capable of maintaining the desired quality of the radio channel signal is set appropriately for the characteristics of the mobile communication system.

However, when performing power control using only the closed loop power control scheme, even though the same SIR has the same SIR, the BER or BLER actually measured varies according to the channel environment, thereby obtaining a higher or lower BER than the target BER. The problem arises that the capacity of the entire mobile communication system is inefficiently used. That is, the correspondence relationship between the SIR and the BER is irregularly changed depending on external factors such as a channel environment or a moving speed of the UE.

Therefore, it is necessary to control power so that the target SIR value to be used for the closed loop power control scheme can be adaptively changed in the channel situation without fixing the specific value to a specific value, so that the taregt BER can be maintained. This is the external loop power control method. The outer loop power control method is a method of adaptively varying a target SIR used in the closed loop power control method according to channel conditions in order to maintain a specific desired performance index, for example, the target BER.

That is, the open loop power control method or the closed loop power control method, that is, the inner loop power control method is generally a fast loop, and can directly compensate for a path loss or interference phenomenon seen at the receiving end. In contrast, the outer loop power control scheme generally provides low throughput and compensation for topological (UE speed, multipath, envelope statistics, etc.) or statistically varying channel conditions. It is possible. Here, high speed power control is the most important factor in power control of a W-CDMA communication system that must transmit high speed packet data, and particularly in reverse power control. The reason is that if high transmission power control is not performed in the reverse direction, excessive transmission power of each of the UEs may affect the call quality of the entire cell, resulting in serious system performance degradation. For example, when the base station fails to perform power control with the same transmission power for each of the different UEs, the UE that is located at a short distance in the base station has a larger transmission power than the UEs that are relatively far from the base station. This affects the communication of other UEs in the base station. That is, it will cause a near-far problem, so that the base station must perform power control so that the power received from each of the UEs is the same.

As a result, the most preferred power control method for accurately controlling the transmission power in the W-CDMA communication system is a fast closed loop power control method, and a fast closed loop power control method will be described with reference to FIG. 2.                         

2 is a flowchart illustrating a transmission power control process according to a general fast power control method.

Referring to FIG. 2, in step 211, the base station initializes parameters related to transmission power control and then proceeds to step 213. Here, the parameters include a target SIR, a target BER or a target BLER. In step 213, the base station sets the target SIR and the target BLER as default values, and then proceeds to step 215. In step 215, the base station receives a specific channel signal, for example, a reverse DPCH signal, measures an SIR, and then proceeds to step 217. In step 217, the base station determines whether the measured SIR value exceeds the target SIR value. If the measured SIR value exceeds the target SIR value, the base station proceeds to step 219. In step 219, the base station generates an up TPC command to increase reverse transmission power for the UE that has transmitted the reverse DPCH signal. In step 221, the base station transmits the generated up TPC command to the UE, controls the UE to increase transmission power, and then proceeds to step 227.

In step 217, if the measured SIR value is less than or equal to the target SIR value, the base station proceeds to step 223. In step 223, the base station generates a TPC (down TPC) command for reducing the reverse transmission power for the UE that transmitted the reverse DPCH signal, and proceeds to step 225. In step 225, the base station transmits the generated down TPC command to the UE, controls the UE to reduce transmission power, and then proceeds to step 227. In step 227, the base station checks whether an entire block has been received from the UE. If the entire block is not received as a result of the check, the base station returns to step 217. If the entire block is received from the UE as a result of the check in step 227, the base station proceeds to step 229. In step 229, the base station measures the BLER for the entire block and checks whether the measured BLER value is less than the previously measured BLER value. If the measured BLER value is less than the previously measured BLER value, the base station proceeds to step 231. In step 231, the base station determines that the channel state of the UE is in a relatively good state, decreases the target SIR value of the UE, and returns to step 217. On the other hand, if the measured BLER value is greater than the previously measured BLER value as a result of the test in step 229, it is determined that the channel state of the UE is relatively poor, and increases the target SIR value of the UE and returns to step 217. Goes.

As described with reference to FIG. 2, the operation of performing transmission power control corresponding to the TPC command by measuring a channel signal received from the UE and transmitting a TPC command corresponding thereto may cause a path loss. It must proceed faster than a large channel state change and must also be faster than the speed of Rayleigh fading seen in low and medium UEs. This is because closed loop power control can prevent power imbalance between all reverse link signals received at the base station.

Meanwhile, although the internal root power control method has been described with reference to FIG. 2, as described above, the power control method includes an outer loop power control method, and the outer loop power control method is mostly defined such as a target BER or a target BLER. It is possible to adjust the set point of the target SIR at the base station by targeting a certain quality or by the needs of each radio link. The required SIR (typically BLER = 1%) is largely determined by the speed or multipath profile of the UE. As an example, assuming that the target SIR set point is a high speed UE and a worst case speed, capacity reduction occurs when the UE is at a worst speed than when the UE is high speed. Therefore, the set point of the target SIR is set to be fluid near the lowest target SIR value to obtain the required target BLER. Here, the set point of the target SIR is changed in accordance with the speed of the UE or the temporal change of the radio channel environment. As a result, the outer loop power control scheme makes it possible to maintain a call at a desired quality by adjusting the required target BLER value through fast power control.

Meanwhile, as another outer loop power control method for performing the transmission power control, the UE reports a quality measurement value to a network, and the network reports a target value for forward fast power control with the quality measurement value reported by the UE. There is a network based forward outer loop power control scheme instructing the UE to adjust. Since the network-based forward outer loop power control scheme causes an increase in signal between the UE and the RNC and a delay of forward power control, a UE-based outer loop power control scheme is generally used.

Meanwhile, problems related to transmission power control for the HS-SCCH in the current W-CDMA TDD communication system are as follows.

First, since the current HS-SCCH is a channel transmitted to all UEs in a cell, whether the specific UE should receive the HS-SCCH by transmitting a UE ID for distinguishing the specific UE for transmission to the specific UE. Can be distinguished. However, a problem occurs when an error occurs in the UE when the UE receives the HS-SCCH. That is, when an error occurs when the UE decodes the HS-SCCH for transmission power control of the HS-SCCH, the error occurs because the HS-SCCH received by the UE does not have a UE ID for the UE. The UE cannot discriminate whether an error occurred during decoding after determining that the error is an HS-SCCH to be received by the UE itself through the UE ID as a result of receiving the HS-SCCH. Therefore, the UE cannot accurately extract the target BLER value of the HS-SCCH necessary for the correction of the target SIR value, and thus it is impossible to control the transmission power for the HS-SCCH. As a result, the conventional general outer loop power control scheme as described above has a problem that it is difficult to apply to the transmission power control for the HS-SCCH in the W-CDMA TDD communication system, particularly in the TDD HSDPA communication system.

Accordingly, an object of the present invention is to provide an apparatus and method for controlling transmission power for a fast common control channel in a time division duplexing code division multiple access communication system using a fast forward packet access scheme.                         

Another object of the present invention is to provide an apparatus and method for controlling transmission power for a fast common control channel for minimizing transmission resource consumption in a time division duplexing code division multiple access communication system using a fast forward packet access scheme.

An apparatus for controlling the transmission power of a common control channel in a time division duplexing code division multiple access mobile communication system using a fast forward packet access scheme according to the present invention, receives a common control channel signal, the received common control channel signal A user terminal for generating and transmitting a measurement report for adjusting a transmission power of the mobile station; and receiving the measurement report from the user terminal, and adjusting the transmission power of the common control channel using the received measurement report. It includes a base station.

In addition, in a time division duplexing code division multiple access mobile communication system using a fast forward packet access scheme according to the present invention, a method for controlling a transmission power of a common control channel is provided by a user terminal. Generating a measurement report for adjusting a transmission power for a common control channel signal and transmitting the measurement report to a base station, and the base station receives the measurement report from a user terminal and uses the received measurement report to Adjusting the transmit power.

Hereinafter, with reference to the accompanying drawings, preferred embodiments of the present invention will be described in detail. 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. 3 is a diagram illustrating a fast common information channel structure of a 1.28 Mcps time division duplexing code division multiple access communication system using a fast forward packet access scheme.

3 illustrates a structure of a high-speed shared information channel (HS-SICH) (hereinafter, referred to as an "HS-SICH") of a communication system using a 1.28 Mcps TDD W-CDMA scheme. First, the HS-SICH includes 1 bit (1 bit) indicating ACK / NACK, 6 bits indicating a transport block set size (TBSS), and a modulation format (MF). : 1-bit information indicating a Modulation Format (hereinafter referred to as "MF"). The ACK / NACK is 36 bits, the TBSS is 32 bits, and the MF is 16 bits through the coding and multiplexing process of the HS-SICH. This coded and multiplexed HS-SICH is second interleaved, and the second interleaved signal has two bits (Synchronization Shift) and Transmit Power Control (TPC). Instruction 2 bits are added. In this way, the signal added with the SS and the TPC is generated corresponding to the slot format of the spreading factor (SF: 16) (SF = 16). Here, referring to the slot format of the HS-SICH, the first field (Field 1) and the second field (Field 2) include the information signals of the secondary interleaved HS-SICH, and SS, TPC and midamble ( Midamble).

In FIG. 3, the HS-SICH structure of the communication system using the 1.28Mcps TDD W-CDMA method has been described. Next, the HS-SICH structure of the communication system using the 3.84Mcps TDD W-CDMA method will be described with reference to FIG. Let's explain.

4 is a diagram illustrating a fast common information channel structure of a 3.84 Mcps time division duplexing code division multiple access communication system using a fast forward packet access scheme.

First, the HS-SICH has 1 bit (1 bit) indicating ACK / NACK, 10 bits indicating RTBS / RMF, and 176 bits of zero padding. The ACK / NACK is 36 bits, the RTBS / RMF is 32 bits, and the zero padding is 176 bits as it is. The coded and multiplexed HS-SICH is secondary interleaved, and an SS and a TPC command are added to the secondary interleaved signal. In this way, the signal added with the SS and the TPC is generated corresponding to the slot format when SF is 16 (SF = 16).

Next, a process of controlling a high speed shared control channel (HS-SCCH) (hereinafter, referred to as "HS-SCCH") transmission power will be described with reference to FIG. 5.

5 is a flowchart illustrating a fast common control channel transmit power control process according to an embodiment of the present invention.

In FIG. 5, operations of a base station Node B and a user terminal (hereinafter referred to as "UE") are present in a mixed state, and are shown in a flowchart for convenience of description. Referring to FIG. 5, the base station first transmits an HS-SCCH to a specific UE in step 511 and then proceeds to step 513. In step 513, the UE receives the HS-SCCH transmitted by the base station and proceeds to step 515. In step 515, if the UE ID of the received HS-SCCH (hereinafter, referred to as UE ID) matches the UE ID of the UE, the UE proceeds to step 517. In step 517, the UE measures the received HS-SCCH and proceeds to step 519. In step 519, the UE generates parameters for a measurement report required for the HS-SCCH transmission power control using the measured HS-SCCH signal. Here, the parameters for the measurement report will be described.

(1) Received Signal Code Power (RSCP) (hereinafter referred to as "RSCP") of a first common control physical channel (P-CCPCH: Primary Common Control Physical CHannel, hereinafter referred to as "P-CCPCH") By using the P-CCPCH RSCP, that is, path loss can be measured from the difference between the P-CCPCH transmission power and the P-CCPCH RSCP.

(2) Interference Signal Code Power (ISCP) (hereinafter referred to as "ISCP"): A value measured in the HS-SCCH time slot of the UE and representing the power strength of the interference signal.

(3) HS-SCCH RSCP: The most recently measured HS-SCCH RSCP value, which will be referred to as a Signal to Interference Ratio (SIR) of the HS-SCCH transmitted from the base station to the UE. ) Is used for measurement.

In step 521, the UE selects parameters to be used for the actual measurement report among the parameters for the measurement report, and then proceeds to step 523. In this case, all of the parameters described in step 519 may be selected or only some of the parameters used in the actual measurement report. In step 523, the UE transmits the measurement report to the base station through the HS-SICH. Then, in step 525, the base station receives the HS-SICH transmitted by the UE, detects the measurement report included in the received HS-SICH, and then transmits the next transmission time interval (corresponding to the detected measurement report). TTI: Transmit Time Interval (hereinafter referred to as "TTI") to adjust the transmit power of the HS-SCCH for the UE, and then proceed to step 527. In step 527, the base station continuously performs an operation of controlling the transmission power for the HS-SCCH as described above.

Here, the measurement report method proposed by the present invention for transmission power control of the HS-SCCH will be described below.

In the first method, the UE transmits only the P _differenc value using the RSCP measurement value of the P-CCPCH and the time slot ISCP measurement value of the HS-SCCH as the measurement report to the base station through the HS-SICH, so that the base station transmits the transmission power of the HS-SCCH. How to adjust.

The reporting range of the P-CCPCH RSCP is -115 to -25 dBm. Here, the measured P-CCPCH RSCP according to the value is summarized in Table 1 below.

In Table 1, the value of P-CCPCH RSCP is divided into 92 steps from 00 to 91. Therefore, when the UE transmits the 92 steps to the base station through the HS-SICH, 7 bits are added. It is necessary.

On the other hand, the reporting range of the time slot ISCP of the HS-SCCH is -115 ~ 25dBm. Here, the timeslot ISCP of the measured HS-SCCH can be summarized according to the values as shown in Table 2 below.                     

In Table 2, it can be seen that the time slot ISCP value of the HS-SCCH is divided into 92 steps from 00 to 91. Therefore, when the UE transmits the 92 steps to the base station through the HS-SICH, 7 bits are required. That is, at least 14 bits are required for the UE to transmit the value of the P-CCPCH RSCP and the value of the time slot ISCP of the HS-SCCH to the base station through the HS-SICH.

Thus, when the UE transmits the value of the P-CCPCH RSCP and the value of the time slot ISCP of the HS-SCCH to the base station, the base station transmits the transmit power of the HS-SCCH to be applied to the next TTI as shown in Equation 1 below. Calculate

In Equation 1, the P _HS-SCCH value represents the transmission power to be applied to the HS-SCCH in the next TTI, and the transmission power of the HS-SCCH is converted to the P-CCPCH transmission power and P to the target SIR value of the transmitted HS-SCCH. Adds the path loss, which is the difference between RSCP for CCPCH, and the ISCP value for HS-SCCH, and adds the path loss and power loss due to interference with the target SIR to finally apply to the next TTI. Determine the transmit power of.

Meanwhile, Equation 1 may be expressed as Equation 2 below.

In Equation 2, if P _difference = RSCP _P-CCPCH -ISCP _HS-SCCH , Equation 2 can be expressed as Equation 3 below.

Equation 3 enables the UE to transmit only the P _differenc value using the RSCP measurement value and the ISCP measurement value to the base station through the HS-SICH as a measurement report, compared to the measurement report as shown in Equation 1 above. It is possible to reduce the number of measurement report bits that the UE should send over the HS-SICH to the base station. As a result, the number of bits for the measurement report is reduced, which makes it possible to increase the transmission capacity of the reverse link. Here, 8 bits are required to transmit the P _difference through the HS-SICH.

The second method is a method in which the base station adjusts the transmission power of the HS-SCCH by transmitting the SIR value of the HS-SCCH to the base station through the HS-SICH as a measurement report.

First, the SIR's reporting range is between -11 and 20 dB. 8 is a table sorted by the measured SIR according to the value.

The measured SIR of the HS-SCCH is divided into 64 different values, and thus, 6 bits are required to transmit the measured SIR value of the HS-SCCH from the user terminal to the base station through the HS-SICH. In this case, the transmission power of the HS-SCCH may be determined by Equation 4 in the base station.

= P _HS-SCCH- old-(RSCP _HS-SCCH -ISCP _HS-CCCH ) + SIR _T-HS-SCCH

= P _HS-SCCH-old -SIR _mea + SIR _{T_HS-SCCH}

Equation 4 may be expressed as Equation 5 below.

In Equation 5, P _HS-SCCH-new denotes a transmission power of a new HS-SCCH, that is, an HS-SCCH transmission power to be applied to a next TTI, and P _{HS_SCCH-old} : denotes a transmission power of the last HS-SCCH. SIR _mea refers to the SIR value of the HS-SCCH measured by the UE and reported to the base station. That is, the P _HS-SCCH-new value is the transmission power of the HS-SCCH to be transmitted to the next TTI, which is a value of P _HS-SCCH-old- RSCP _HS-SCCH which is a path loss to a target SIR value, that is, the transmission. The difference between the HS-SCCH received signal power value received at the UE and the ISCP can be obtained by adding the received HS-SCCH transmit power. The targets of the transmission and reception powers are all based on the HS-SCCH, and in Equation 5, the RSCP _HS-SCCH- ISCP _HS-CCCH value is the SIR value of the HS-SCCH when viewed in logarithmic scale. That is, the RSCP _HS-SCCH- ISCP _HS-CCCH value is measured by the UE and indicates the SIR value of the last reported HS-SCCH to the base station.

Here, in the second method, the bits required for the UE to transmit the measurement report to the base station through the HS-SICH are 6 bits, and the measured SIR values are shown in Table 3 below.

In Table 3, it can be seen that the SIR value is divided into 64 steps from 00 to 63, and thus, 6 bits are required when the UE transmits the 64 steps to the base station through the HS-SICH. .                     

Next, an HS-SCCH transmitter structure for performing a function in an embodiment of the present invention will be described with reference to FIG. 6.

6 illustrates a structure of a fast common information channel transmitter for performing a function in an embodiment of the present invention.

Referring to FIG. 6, first, the HS-SICH selects one of QPSK and 16QAM in the next TTI according to ACK / NACK 611 information for the previous HS_SCCH signal, TBSS 613, and channel state. MF information 615 indicating whether to perform modulation, and measurement report (MR) 617 information are included. This ACK / NACK 611 information, TBSS 613, MF information 615 and MR information 617 is input to the encoder 619, the encoder 619 is the input ACK / NACK 611 ) Information, the TBSS 613, the MF information 615, and the MR information 617 are encoded in a predetermined coding scheme and then output to the interleaver 621. The coding scheme may be a block coding scheme or a convolutional coding scheme. In addition, an orthogonal coding scheme for channel classification may be used.

The interleaver 621 interleaves the signal output from the encoder 619 by an interleaving method which is set in advance to prevent burst error, and then outputs the signal to the multiplexer 629. The multiplexer 629 is referred to as a signal output from the interleaver 621, a TPC 623, an SS 625, and a transport format combination indicator (TFCI). ) And multiplexing it by outputting the same to the spreader 631. Here, the TPC 623, the SS 625, and the TFCI 627 are used only for HS-SICH transmission of the NB-TDD communication system, and are not used for HS-SICH transmission of the WB-TDD communication system.

The spreader 631 inputs the signal output from the multiplexer 629, _spreads the signal with the preset channelization code C _OVSF , and outputs the spread signal to the multiplier 633. The multiplier 633 multiplies the signal output from the spreader 631 with a preset gain parameter and outputs the multiplier 635 to the multiplier 635. The multiplier 635 multiplies the signal output from the multiplier 633 with a preset scrambling code C _SCRAMBLE and outputs the multiplier 639. Here, the multiplier 738 operates as a scrambler. The multiplexer 639 inputs and multiplexes the signal output from the multiplier 635 and the midamble 637 and outputs the multiplexer 641 to the modulator 641. Here, the multiplexer 639 divides the signal output from the multiplier 635 into two parts, and the midamble 637 is inserted between the divided signals. The signals of the two parts, the midamble 637, and a guard period (GP) constitute one reverse time slot. The midamble 637 is used for distinguishing UEs using the same time slot or base station channels using the same time slot, and used for channel estimation in forward / reverse transmission, and from base station to UE in forward transmission. It is used to measure how much loss is along the channel path, or it is also used to distinguish base stations by using different midambles for each of the base stations. A specific sequence is used for the midamble 637, and there are 128 kinds of the specific sequence. Each base station uses one of the specific sequences so that each of the UEs in the base station uses a shifted version of the particular sequence. In addition, the GP is a section for removing interference caused by a multi-path delay occurring between a reverse time slot and a forward time slot such as interference caused by overlapping a forward time slot and a reverse time slot. No signal is transmitted.

The modulator 641 inputs a signal output from the multiplexer 639, modulates the signal by a modulation scheme preset in the base station, and outputs the modulated signal to a radio frequency (RF) processor 643. Here, the modulation scheme may be a method such as quadrature phase shift keying (QPSK) or 8 phase shift keying (8PSK). The RF processor 643 receives a signal output from the modulator 641, converts the signal into an RF band signal, and transmits the signal over an air through an antenna 645.

In FIG. 6, the structure of the HS-SICH transmitter is described. Next, the structure of the HS-SICH receiver will be described with reference to FIG. 7.

FIG. 7 illustrates a structure of a fast common information channel receiver for performing a function in an embodiment of the present invention.

Referring to FIG. 7, when a signal is first received from the air through the antenna 711, the received signal is output to the RF processor 713. The RF processor 713 converts the received signal into a base band signal and outputs it to a demodulator 717. The demodulator 717 demodulates the signal output from the RF processor 713 into a demodulation scheme corresponding to the modulation scheme applied by the HS-SICH transmitter, that is, the UE, and then outputs the demodulator to the demultiplexer (DEMUX) 719. . The demultiplexer 719 demultiplexes the signal output from the demodulator 717 into a midamble 723 and the remaining signal, and then outputs a signal excluding the midamble 723 to the multiplier 721. . The multiplier 721 descrambles the same scrambling code C _SCRAMBLE with the same scrambling code applied by the HS-SICH transmitter, and outputs the descrambler to the de-spreader 725. Here, the multiplier 721 operates as a descrambler. The despreader 725 despreads the signal output from the multiplier 721 with the same channelization code C _OVSF as the channelization code applied by the HS-SICH transmitter to reverse HS = SICH signals of other UEs, The signal is separated into a backward signal of the corresponding UE, and the reverse HS = SICH of the corresponding UE is output to the demultiplexer 727. The demultiplexer 727 demultiplexes the signal output from the despreader 725 to separate the TPC 733, the SS 735, and the TFCI 737, and decode the remaining signals, that is, actual user data. Output to the interleaver (de-interleacer) (731). The deinterleaver 731 deinterleaves the signal output from the demultiplexer 727 in a deinterleaving manner corresponding to the interleaving scheme applied by the HS-SICH transmitter, and then outputs the deinterleaver to the decoder 739. The decoder 739 decodes the signal output from the deinterleaver 731 using a decoding method corresponding to the coding method applied by the HS-SICH transmitter, and outputs the actual user data 741. The user data 741 is eventually data related to the measurement report sent by the UE to control HS-SCCH transmit power. Therefore, the base station calculates the transmission power to be applied to the next TTI with the measurement report and transmits the HS-SCCH with the calculated transmission power from the next TTI.

Meanwhile, in the detailed description of the present invention, specific embodiments have been described, but various modifications are possible without departing from the scope of the present invention. Therefore, the scope of the present invention should not be limited to the described embodiments, but should be defined not only by the scope of the following claims, but also by the equivalents of the claims.

As described above, the present invention has the advantage that it is possible to accurately control the HS-SCCH transmission power at high speed without a separate signal load in the TDD CDMA mobile communication system using the HSDPA scheme. In addition, there is an advantage of maximizing system transmission resource capacity by minimizing the number of bits of the measurement report value transmitted to control the HS-SCCH transmission power and minimizing the consumption of backward transmission resources.

Claims (12)

A method of controlling transmission power of a common control channel by transmitting a measurement report in a time division duplexing code division multiple access mobile communication system using a fast forward packet access scheme, Receiving a first channel signal, a common control channel signal from a base station, measuring received power of the first channel signal, and interference power of the common control channel signal; And generating, by the measurement report, a path loss that is a difference between the received power and the interference power, and transmitting the measurement report through a second channel. The method of claim 1, wherein the first channel signal, A transmit power control method that is a first common control physical channel signal. The method of claim 1, wherein the second channel, Transmission power control method that is a common information channel. A method of controlling transmission power of a common control channel by transmitting a measurement report in a time division duplexing code division multiple access mobile communication system using a fast forward packet access scheme, Receiving a common control channel signal from a base station and measuring a signal-to-interference ratio of the common control channel signal; Transmitting the measurement report through the first channel after generating the signal-to-interference ratio as the measurement report. The method of claim 4, wherein the first channel, Transmission power control method that is a common information channel. A method for controlling transmit power of a common control channel in a time division duplexing code division multiple access mobile communication system using a high speed forward packet access method, Receiving from the user terminal a measurement report comprising a path loss which is a difference between the received power of the first channel and the interference power of the common control channel; And adjusting the transmit power of the common control channel with the transmit power of the first channel, the path loss and the target signal-to-interference ratio of the common control channel. The method of claim 6, wherein adjusting the transmit power of the common control channel comprises: And subtracting the path loss from the transmit power of the first channel and adding a target signal-to-interference ratio of the common control channel. The method of claim 6, wherein the first channel, A transmit power control method that is a first common control physical channel. A method for controlling transmit power of a common control channel in a time division duplexing code division multiple access mobile communication system using a high speed forward packet access method, Receiving a measurement report including a signal-to-interference ratio of the common control channel from a user terminal; And adjusting the transmit power of the common control channel using the signal-to-interference ratio of the common control channel. The method of claim 9, wherein adjusting the transmit power of the common control channel comprises: And subtracting the signal-to-interference ratio from the transmission power of the common control channel and then adding and determining a target signal-to-interference ratio of the common control channel. An apparatus for controlling transmit power of a common control channel in a time division duplexing code division multiple access mobile communication system using a high speed forward packet access method, A user terminal for receiving a common control channel signal, generating a measurement report for adjusting a transmission power of the received common control channel signal, and transmitting the measurement report to a base station; And the base station receiving the measurement report from the user terminal and adjusting the transmission power of the common control channel using the received measurement report. A method for controlling transmit power of a common control channel in a time division duplexing code division multiple access mobile communication system using a high speed forward packet access method, Receiving, by a user terminal, a common control channel signal, generating a measurement report for adjusting a transmission power of the received common control channel signal, and transmitting the measurement report to a base station; And receiving, by the base station, the measurement report from a user terminal, and adjusting the transmission power of the common control channel by using the received measurement report.

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