US20110110257A1

US20110110257A1 - Uplink transmission power control method in a wireless communication system

Info

Publication number: US20110110257A1
Application number: US12/996,974
Authority: US
Inventors: Dong Cheol Kim; Min Seok Noh; Yeong Hyeon Kwon; Jin Sam Kwak; Sung Ho Moon; Seung Hee Han; Hyun Woo Lee
Original assignee: LG Electronics Inc
Current assignee: LG Electronics Inc
Priority date: 2008-07-08
Filing date: 2009-07-08
Publication date: 2011-05-12
Also published as: WO2010005239A3; CN102089998A; WO2010005239A2; WO2010005238A2; WO2010005238A3; WO2010005237A2; WO2010005237A3; US8531975B2; US20110116408A1; US20110134759A1

Abstract

Provided is an uplink transmission power control method in a wireless communication system. Said method includes preferentially determining the transmission power of an uplink control channel, and determining the transmission power of an uplink data channel within the difference between the maximum transmittable power of a terminal and the transmission power of the uplink control channel, wherein the transmission of the uplink control signal through the uplink control channel and the transmission of the uplink data through the uplink data channel are performed at the same time using wireless resources different from one another. The present invention preferentially allocates the transmission power required for the transmission of an uplink control channel, and allocates residual power to an uplink data channel, thereby improving the effectiveness of power allocation when an uplink control signal and an uplink data signal are transmitted at the same time using physical resources different from one another.

Description

TECHNICAL FIELD

The present invention relates to wireless communications, and more particularly, to a method of controlling uplink transmission power when an uplink control signal and an uplink data signal are simultaneously transmitted by using different radio resources in an 802.16m system.

BACKGROUND ART

The institute of electrical and electronics engineers (IEEE) 802.16e standard was adopted in 2007 as a sixth standard for international mobile telecommunication (IMT)-2000 in the name of ‘WMAN-OFDMA TDD’ by the ITU-radio communication sector (ITU-R) which is one of sectors of the international telecommunication union (ITU). An IMT-advanced system has been prepared by the ITU-R as a next generation (i.e., 4^thgeneration) mobile communication standard following the IMT-2000. It was determined by the IEEE 802.16 working group (WG) to conduct the 802.16m project for the purpose of creating an amendment standard of the existing IEEE 802.16e as a standard for the IMT-advanced system. As can be seen in the purpose above, the 802.16m standard has two aspects, that is, continuity from the past (i.e., the amendment of the existing 802.16e standard) and continuity to the future (i.e., the standard for the next generation IMT-advanced system). Therefore, the 802.16m standard needs to satisfy all requirements for the IMT-advanced system while maintaining compatibility with a mobile WiMAX system conforming to the 802.16e standard.
An orthogonal frequency division multiplexing (OFDM) system capable of reducing inter-symbol interference (ISI) with a low complexity is taken into consideration as one of next generation wireless communication systems. In the OFDM, a serially input data symbol is converted into N parallel data symbols, and is then transmitted by being carried on each of separated N subcarriers. The subcarriers maintain orthogonality in a frequency dimension. Each orthogonal channel experiences mutually independent frequency selective fading, and an interval of a transmitted symbol is increased, thereby minimizing inter-symbol interference. In a system using the OFDM as a modulation scheme, orthogonal frequency division multiple access (OFDMA) is a multiple access scheme in which multiple access is achieved by independently providing some of available subcarriers to a plurality of users. In the OFDMA, frequency resources (i.e., subcarriers) are provided to the respective users, and the respective frequency resources do not overlap with one another in general since they are independently provided to the plurality of users. Consequently, the frequency resources are allocated to the respective users in a mutually exclusive manner. In an OFDMA system, frequency diversity for multiple users can be obtained by using frequency selective scheduling, and subcarriers can be allocated variously according to a permutation rule for the subcarriers.
In the 802.16m system, when a user equipment (UE) transmits an uplink signal to a base station (BS), an uplink control channel for transmitting a control signal and an uplink data channel for transmitting data can be physically divided, and the uplink control signal and the uplink data can be simultaneously transmitted by using one symbol. Transmission power of the uplink control channel and the uplink data channel can be determined by using formulas.
Meanwhile, maximum transmissible power that can be allocated by the UE for uplink transmission is predetermined in general according to a bandwidth assigned to the UE. Therefore, if a sum of the transmission power of the uplink control channel and the transmission power of the uplink data channel (herein, the transmission power is determined by the formulas) is greater than the maximum transmissible power, uplink transmission cannot be achieved properly since power required for uplink transmission is not enough. In particular, if the power allocated to the uplink control channel is not enough, a big problem may occur in operating the wireless communication system.
Accordingly, there is a need for a method for effective power allocation when an uplink control signal and uplink data are simultaneously transmitted by using different physical regions.

DISCLOSURE

Technical Problem

The present invention provides a method of controlling uplink transmission power when a control signal and a data signal are simultaneously transmitted by using different uplink physical resources in an 802.16m system.

Technical Solution

In an aspect, a method of controlling uplink transmission power in a wireless communication system is provided. The method include determining preferentially transmission power of an uplink control channel, and determining transmission power of an uplink data channel within a difference between maximum transmissible power of a user equipment and the transmission power of the uplink control channel, wherein an uplink control signal transmitted through the uplink control channel and uplink data transmitted through the uplink data channel are simultaneously transmitted by using different radio resources. The transmission power of the uplink control channel may be determined by a power control equation, and the transmission power of the uplink control channel may be determined by the predetermined transmission power level. The transmission power of the uplink data channel may be determined by a power control equation, and the transmission power of the uplink data channel may be determined by a predetermined transmission power level.
Also, the uplink control channel and the uplink data channel may belong to different regions divided according to a frequency. A region to which the uplink control channel belongs may be a common region of a cell. A region to which the uplink data channel belongs may be one of a part of the common region remaining after the uplink control channel is allocated, an active region, and an inactive region.
In another aspect, a user equipment (UE) in a wireless communication system is provided. The UE include a data processor for processing an uplink control signal and uplink data, a power controller for controlling a power resource to be allocated to an uplink control channel and an uplink data channel, and a radio frequency (RF) unit for transmitting the uplink control signal through the uplink control channel and for transmitting the uplink data through the uplink data channel, wherein the power controller determines preferentially transmission power of an uplink control channel, and determines transmission power of an uplink data channel within a difference between maximum transmissible power of a user equipment and the transmission power of the uplink control channel.

Advantageous Effects

According to the present invention, power required to transmit an uplink control channel is preferentially allocated and the remaining power is allocated to an uplink data channel. Therefore, mutual interference can be effectively controlled when an uplink control signal and an uplink data signal are simultaneously transmitted by using different physical resources, and power can be effectively allocated.

DESCRIPTION OF DRAWINGS

FIG. 1 shows a wireless communication system.

FIG. 2 shows an example of a frame structure.

FIG. 3 shows an example of a resource region in case of not using

an FFR.

FIG. 4 shows an example of a UL transmission power control method according

to a power control formula.

FIG. 5 shows an example of a UL transmission power control method using a

maximum transmission power level.

FIG. 6 shows an exemplary structure of a cell using the FFR.

FIG. 7 shows an example of a resource region using a hard FFR.

FIG. 8 shows an example of a resource region using a soft FFR.

FIG. 9 shows an example of a UL transmission power control method when

using a hard FFR.

FIG. 10 shows another example of a UL transmission power control method

when using a hard FFR.

FIG. 11 is a block diagram of a UE according to an embodiment of the present invention.

MODE FOR INVENTION

FIG. 1 shows a wireless communication system. A wireless communication system 10 includes at least one base station (BS) 11. Respective BSs 11 provide communication services to specific geographical regions (generally referred to as cells) 15 a, 15 b, and 15 c. The cell can be divided into a plurality of regions (referred to as sectors). A user equipment (UE) 12 may be fixed or mobile, and may be referred to as another terminology, such as a mobile station (MS), a mobile terminal (MT), a user terminal (UT), a subscriber station (SS), a wireless device, a personal digital assistant (PDA), a wireless modem, a handheld device, etc. The BS 11 is generally a fixed station that communicates with the UE 12 and may be referred to as another terminology, such as an evolved node-B (eNB), a base transceiver system (BTS), an access point, etc.
This technique can be used in an uplink or a downlink. In general, the downlink denotes communication from the BS 11 to the UE 12, and the uplink denotes communication from the UE 12 to the BS 11. In the downlink, a transmitter may be a part of the BS 11, and a receiver may be a part of the UE 12. In the uplink, the transmitter may be a part of the UE 12, and the receiver may be a part of the BS 11.
FIG. 2 shows an example of a frame structure. A frame is a data sequence used according to a physical specification in a fixed time duration. The section 8.4.4.2 of IEEE standard 802.16-2004 “Part 16: Air Interface for Fixed Broadband Wireless Access Systems” can be incorporated herein by reference.
Referring to FIG. 2, the frame includes a downlink (DL) frame and an uplink (UL) frame. When using a time division duplex (TDD) scheme, the UL and DL transmissions are achieved at different times while sharing the same frequency. The DL frame temporally precedes the UL frame. The DL frame sequentially includes a preamble, a frame control header (FCH), a DL-MAP, a UL-MAP, and a burst region. Guard times are provided to identify the UL frame and the DL frame and are inserted to a middle portion (between the DL frame and the UL frame) and a last portion (next to the UL frame) of the frame. A transmit/receive transition gap (TTG) is a gap between a DL burst and a subsequent UL burst. A receive/transmit transition gap (RTG) is a gap between a UL burst and a subsequent DL burst.
The preamble is used between a BS and a UE for initial synchronization, cell search, and frequency-offset and channel estimation. The FCH includes information on a length of a DL-MAP message and a coding scheme of the DL-MAP.
The DL-MAP is a region for transmitting the DL-MAP message. The DL-MAP message defines access to a DL channel. This implies that the DL-MAP message defines indication and/or control information for the DL channel. The DL-MAP message includes a configuration change count of a downlink channel descriptor (DCD) and a BS identifier (ID). The DCD describes a DL burst profile applied to a current MAP. The DL burst profile indicates characteristics of a DL physical channel. The DCD is periodically transmitted by the BS by using a DCD message.
The UL-MAP is a region for transmitting a UL-MAP message. The UL-MAP message defines access to a UL channel. This implies that the UL-MAP message defines indication and/or control information for the UL channel. The UL-MAP message includes a configuration change count of an uplink channel descriptor (UCD) and also includes an effective start time of UL allocation defined by the UL-MAP. The UCD describes a UL burst profile. The UL burst profile indicates characteristics of a UL physical channel and is periodically transmitted by the BS by using a UCD message.
The DL burst is a region for transmitting data transmitted by the BS to the UE. The UL burst is a region for transmitting data transmitted by the UE to the BS.
A UL control signal and UL data are transmitted in a UL subframe. For this, a UL control channel and a UL data channel are allocated. Examples of the UL control channel include a fast feedback channel (FFBCH), a bandwidth request channel (BRCH), an HARQ feedback channel (HFBCH), a sounding channel, a ranging channel, etc. The FFBCH is a channel for UL transmission faster than normal UL data. The BRCH is a channel for requesting radio resources for transmitting UL data or control signals to be transmitted by the UE. The HFBCH is a channel for transmitting an acknowledgment (ACK)/non-acknowledgment (NACK) signal in response to data transmission. The sounding channel is a channel for UL closed-loop multiple-in multiple-out (MIMO) transmission and UL scheduling. The ranging channel is a channel for UL synchronization. By using the aforementioned various control channels, control information such as ACK/NACK, a channel quality indicator (CQI), a precoding matrix index (PMI), etc., can be transmitted.
For transmission of the UL control signal and the UL data, there is a need to allocate power required for the UL control channel and the UL data channel. In general, a transmission power level of the UL control channel and the UL data channel can be calculated by Equation 1 and Equation 2. Hereinafter, a formula having a format of Equation 1 or Equation 2 is called a power control formula.
P _PSD _— _ctrl(dBm)=L+SINR _Target _— _ctrl+NI+OffsetAMS_perAMS+OffsetABS_perAMS [Equation 1]
P _PSD _— _data(dBm)=L+SINR _Target _— _data+NI+OffsetAMS_perAMS+OffsetABS_perAMS [Equation 2]
In Equation 1 above, P_PSD _— _ctrldenotes a power spectral density (PSD) of transmission power of the UL control channel in a dBm unit when using an open-loop power control scheme. Hereinafter, the PSD of the transmission power of the UL control channel is referred to as a transmission power level of the UL control channel. The PSD can be expressed on a subcarrier basis or a frequency basis. L denotes an average estimation value of a UL propagation loss. SINR_Target _— _ctrldenotes a target signal-to-interference plus noise ratio (SINR) value of the UL control channel received by the BS. NI (i.e., noise and interference) denotes an average estimation value between noise and an interference level. OffsetAMS_perAMSand OffsetABS_perAMSdenote offset values controlled respectively by the UE and the BS.
In Equation 2 above, P_PSD _— _datadenotes a PSD of transmission power of the UL data channel in a dBm unit when using the open-loop power control scheme. Hereinafter, the PSD of the transmission power of the UL data channel is referred to as a transmission power level of the UL data channel. The PSD can be expressed on a subcarrier basis or a frequency basis. L denotes an average estimation value of a UL propagation loss. SINR_Target _— _datadenotes a target SINR value of the UL data channel received by the BS. NI denotes an average estimation value between noise and an interference level. OffsetAMS_perAMSand OffsetABS_perAMSdenote offset values controlled respectively by the UE and the BS.
The transmission power allocated to the UL control channel and the UL data channel can be obtained by using the values P_PSD _—ctrland P_PSD _— _data. Although transmission power of each channel can be obtained by using several methods, it can be basically calculated by Equation 3 and Equation 4.
P _total _— _ctrl =P _ctrl ×Mt×BW [Equation 3]
P _total _— _data =P _data ×Mt×BW [Equation 4]
In Equation 3 and Equation 4 above, Mt denotes the number of streams. BW denotes a size of a bandwidth assigned for transmission of each UE.
Hereinafter, a UL transmission power control method proposed in the present invention will be described.
Maximum transmissible power P_Maxof a UE has a different value for each system. The UE has to determine a transmission power level of each channel in a range not exceeding a limited P_max. If a sum of P_total _— _ctrland P_total _— _dataobtained by Equation 3 and Equation 4 above is greater than P_max, UL transmission may not be properly achieved. In general, UL data has an opportunity of retransmission using link adaption or hybrid automatic repeat request (HARM), whereas a UL control signal does not have an opportunity of retransmission. Therefore, the UL control signal needs to be transmitted with a high importance level, and thus a power resource has to be allocated preferentially for a UL control channel. This can be expressed by the following equation.
P _Max −P _total _— _ctrl ≦P _total _—data [Equation 5]
That is, transmission power allocated to a UL data channel has to be less than a value obtained by subtracting transmission power preferentially allocated to the UL control channel from maximum transmission power of the UE. The proposed invention will be described hereinafter on the premise that a power resource is preferentially allocated to the UL control channel as expressed in Equation 5 above.
First, the UL transmission power control method will be described in case of not using a fractional frequency reuse (FFR). The FFR implies the use of an assigned bandwidth by splitting the bandwidth by using different reuse factors. The FFR can be used when separate radio resources belonging to different regions are intended to be used for a particular purpose. For example, in order to increase throughput in a cell edge in one cell, a part of the bandwidth may be allocated to a cell edge portion by splitting the bandwidth.
FIG. 3 shows an example of a resource region in case of not using an FFR. A portion in which a UL control signal is transmitted is separated from a portion in which UL data is transmitted. The UL control signal and the UL data can be simultaneously transmitted in one symbol.
FIG. 4 shows an example of a UL transmission power control method according to a power control formula.
In step S100, a temporary transmission power level of a UL control channel is calculated. The temporary transmission power level of the UL control channel can be calculated by the power control formula of Equation 1 above.
In step S110, a transmission power level of the UL control channel is determined. This can be expressed by Equation 6 below.
P _ctrl=min(P _PSD _— _total ,P _PSD _— _ctrl) [Equation 6]
In Equation 6 above, P_PSD _— _totalis a maximum transmissible power level of a UE, and P_PSD _— _ctrlis the temporary transmission power level calculated in step S100 above for the UL control channel. The transmission power level P_ctrlof the UL control channel is determined to a smaller value between the two values.
In step S120, a temporary transmission power level of a UL data channel is calculated. The temporary transmission power level of the UL data channel can be calculated by the power control formula of Equation 2 above.
In step S130, a transmission power level of the UL data channel is determined by using the value P_ctrl. This can be expressed by Equation 7 below.
P _data=min(P _PSD _— _total −P _ctrl ,P _PSD _— _data) [Equation 7]
In Equation 7 above, P_PSD _— _datadenotes the temporary transmission power level of the UL data channel. That is, the UL data channel is determined to a smaller value between a value obtained by subtracting transmission power of the UL control channel from the maximum transmission power level and the temporary transmission power level of the UL data channel. According to this method, a sum of the transmission power levels of the UL control channel and the UL control channel does not exceed a maximum transmission power level of the UE.
Alternatively, the transmission power level of each channel may be determined by using a pre-fixed transmission power level. In this case, the transmission power level may be always determined to be greater than or equal to the fixed transmission power level in a place where many reception requests exist such as a hot spot, or the transmission power level may be always determined to be less than or equal to the fixed transmission power level in order to decrease interference to a neighbor cell.
FIG. 5 shows an example of a UL transmission power control method using a maximum transmission power level. In this example, temporary transmission power levels of a UL control channel and a UL data channel are also calculated.
In step S200, a temporary transmission power level of a first region is calculated. The temporary transmission power level of the first region can be calculated by the power control formula.
In step S210, a transmission power level of the first region is determined. This can be expressed by Equation 8 below.
P _region1=min(P _PSD _— _region1 _— _Max ,P _PSD _— _region1) [Equation 8]
In Equation 8 above, P_PSD _— _region1 _— _Maxdenotes a predetermined maximum transmission power level of the first region. P_PSD _— _region1denotes the temporary transmission power level of the first region. The transmission power level of the first region is determined to a smaller value between the two values.
When the first region corresponds to the UL control channel, the first region can be divided into a plurality of regions. Each of the plurality of regions can transmit a different control signal such as CQI, ACK/NACK, etc. In this case, priorities can be assigned according to an importance level of the control signal transmitted in each region, and the transmission power level can be preferentially determined according to an order of the priorities. For example, if the CQI is the most important among the control signals, a transmission power level may be determined preferentially for a region in which the CQI is transmitted in the UL control channel. Regarding the remaining control signals, the transmission power level may be determined from the remaining power resources other than a power resource allocated to the region in which the CQI is transmitted.
In step S220, a temporary transmission power level of a second region is calculated. The temporary transmission power level of the second region can be calculated by a power control formula.
In step S230, a transmission power level of the second region is determined. This can be expressed by Equation 9 below.
P _region2=min(P _PSD _— _region2 _— _Max ,P _PSD _— _region2) [Equation 9]
In Equation 9 above, P_PSD _— _region2Max denotes a predetermined maximum transmission power level of the second region. P_PSD _— _region2denotes the temporary transmission power level of the second region. The transmission power level of the second region is determined to a smaller value between the two values.
When a radio resource is divided for three or more regions, the aforementioned process may be repeated to determine a transmission power level of each region. The method is applicable when a resource of a specific region is limitedly used. However, since a maximum transmission power level is determined and used for all resource regions, there is a demerit in that a power resource cannot be additionally allocated to a portion which requires more power resources.
In the determining of the transmission power level of the second region, the maximum transmission power level of the second region may be not used. Instead, by using a difference between a maximum transmissible power level of a UE and the transmission power level of the first region, the transmission power level of the second region may be determined. This can be expressed by Equation 10 below.
P _region2=min(P _PSD _— _total −P _region1 ,P _PSD _— _region2) [Equation 10]
In Equation 10 above, P_PSD _— _totaldenotes the maximum transmissible power level of the UE, and P_region1denotes the temporary transmission power level of the second region. The transmission power level of the second region is determined to a smaller value between the temporary transmission power level of the second region and a different of P_PSD _— _totaland P_region1.
When the radio resource is divided for three or more regions, the aforementioned process may be repeated to determine the transmission power level of each region. In this case, Equation 10 may be applied to a region which requires a fixed maximum transmission power level, so that power required for each region is effectively allocated.
Hereinafter, a UL transmission power control method in case of using an FFR will be described.
FIG. 6 shows an exemplary structure of a cell using the FFR. Each of cells 300, 310, and 320 are contiguous to each other in a shape of a cube. A center of each of the cells 300, 310, and 320 uses the same frequency region F4. An edge of each of the cells 300, 310, and 320 is divided into three regions F1 to F3 to secure throughput in the edge. In addition, a portion in which each of the cells 300, 310, and 320 are contiguous to each other is configured such that the regions F1 to F3 are not contiguous to each other. In each of the cells 300, 310, and 320, a radio resource can be used in such a manner that a certain region is allocated to an active region and the remaining regions are allocated to inactive regions.
The FFR has two types, i.e., a hard FFR and a soft FFR. The hard FFR uses only the active region without using the inactive region. The soft FFR uses the inactive region as well, by allocating a specific resource to the inactive region. Since the hard FFR does not use a certain part of resources, resource utilization is low, but tends to decrease inter-frequency interference to that extent. Since the soft FFR uses a full band, resource utilization is high, but requires a method of effectively using the inactive region.
FIG. 7 shows an example of a resource region using a hard FFR. The resource region is divided into four regions according to a frequency. A region FP4 occupies a wider frequency region than those of regions FP1 to FP3. However, the present invention is not limited thereto, and thus resources allocated to each region may have a fixed or variable size. When the frequency region is divided into four regions as shown in FIG. 8, the region F4 is generally called a reuse 1 region, and the regions F1 to F3 are called reuse 1/3 regions.
Referring to FIG. 7, the region F4 corresponds to a common region used in all cells 1 to 3. In particular, a UL control signal can be transmitted only in a designated zone of the region F4. In addition, except for the region F4, only the region F1 is allocated to an active region in the cell 1, and is allocated to an inactive region in the cell 2 and the cell 3. Likewise, the region F2 is allocated to an active region only in the cell 2, and the region F3 is allocated to an active region only in the cell 3. Therefore, it can be seen that a resource is allocated only to an active region of each cell. A power resource is also allocated only to the active region and the common region.
FIG. 8 shows an example of a resource region using a soft FFR. Although it is the same structure as the example of FIG. 7, a radio resource and a power resource are allocated even in an inactive region of each cell since the soft FFR is used.
FIG. 9 shows an example of a UL transmission power control method when using a hard FFR. In the present embodiment, only regions F1 and F4 are determined to active regions. Further, UL data is transmitted through the region F1, and a UL control signal is transmitted through a designated zone of the region F4.
In step S400, a temporary transmission power level of a UL control channel is determined. The temporary transmission power level of the UL control channel can be calculated by the power control formula of Equation 1 above.
In step S410, transmission power of the UL control channel is determined. This can be expressed by Equation 11 below.
P _ctrl=min(P _total ,P _PSD _— _ctrl×BW) [Equation 11]
In Equation 11 above, P_totaltotal denotes maximum transmissible power of a UE, and P_PSD _— _ctrldenotes the temporary transmission power level of the UL control channel. BW denotes a bandwidth assigned to the UL control channel. The transmission power P_ctrlof the UL control channel is determined to a smaller value between the two values.
In step S420, a transmission power level of a UL data channel is determined by using the value P_ctrl. This can be expressed by Equation 12 below.
$\begin{matrix} P_{PSD_data} = \frac{P_{total} - P_{ctrl}}{BW} & [Equation 12] \end{matrix}$
In Equation 12 above, P_totaltotal denotes maximum transmissible power of the UE, and P_ctrldenotes transmission power of the UL control channel. BW denotes a bandwidth assigned to the UL data channel. The transmission power level P_PSD _— _dataof the UL data channel is determined to a value obtained by dividing the remaining power excluding the transmission power allocated to the UL control channel by a bandwidth assigned to the region F1.
When the power resource is allocated to the UL control channel as shown in the aforementioned embodiment, the transmission power level of the UL control channel may be determined by using the power control formula as described above, or the power resource may be allocated to the UL control channel by predetermining a maximum transmission power level and the remaining power may be allocated to the UL data channel. In addition, when using the hard FFR, an inactive region has a relatively less effect on the UL control channel, and thus a maximum transmission power level of the UL data channel itself may be predetermined and a power resource may be allocated according to the maximum transmission power level irrespective of the transmission power level of the UL control channel.
FIG. 10 shows another example of a UL transmission power control method when using a hard FFR.
In step S500, the same maximum transmissible power level is assigned to a UL control channel and a UL data channel. This can be determined by dividing maximum transmission power of a UE by a bandwidth of a region in which a resource is allocated.
In step S510, a transmission power level of each of the UL control channel and the UL data channel is determined on the basis of the maximum transmissible power level. In this case, each channel may determine a required transmission power level by using a power control parameter designated for each channel and a common power control parameter which is common in all regions.
In step S520, if the required transmission power level of the UL data channel exceeds the maximum transmissible power level, a remaining power resource is allocated to the UL data channel by comparing the maximum transmissible power level of the UL control channel and the transmission power level. In this case, the remaining power resource may be allocated in a range satisfying the required transmission power level of the UL data channel, or the remaining power resource of the UL control channel may be entirely allocated to the UL data channel irrespective of the required transmission power level.
Even in a case where the required transmission power level of the UL control channel exceeds the maximum transmissible power level, the process of step S520 can be applied. Meanwhile, a plurality of control channels may be allocated. In this case, priorities of the channels may be determined according to a UL control signal contained the UL control channel, and the required transmission power of the UL control channel may be decreased by ignoring some of information having a low priority.
The required transmission power levels of both of the UL control channel and the UL data channel may exceed the maximum transmissible power level. In this case, transmission may be performed with the maximum transmissible power level, or a power resource of a channel having a low priority may be allocated to a channel having a high priority by determining the priorities of the control signal and data.
When using a soft FFR, allocation of a power resource is required for an inactive region. In this case, the transmission power level of the UL control channel may be determined by using a power control formula, and the transmission power level of the inactive region may be determined to the predetermined transmission power level. Alternatively, the transmission power level of the UL control channel may be determined to the predetermined transmission power level, and the transmission power level of the inactive region may also be determined by predetermining the maximum transmissible power level.
FIG. 11 is a block diagram of a UE according to an embodiment of the present invention. A UE 600 includes a data processor 610, a power controller 620, a radio frequency (RF) unit 630, and an antenna 690. The data processor 610 processes a UL control signal and UL data. The power controller 620 controls power resources allocated to a UL control channel for transmitting the UL control signal and a UL data channel for transmitting the UL data. The power controller 620 preferentially determines transmission power of the UL control channel, and determines transmission power of the UL data channel within a difference between maximum transmissible power of the UE and the transmission power of the UL control channel. The RF unit 620 transmits the UL control signal through the UL control channel, and transmits the UL data through the UL data channel.
The present invention can be implemented using hardware, software, or a combination of them. In the hardware implementations, the present invention can be implemented using an Application Specific Integrated Circuit (ASIC), a Digital Signal Processor (DSP), a Programmable Logic Device (PLD), a Field Programmable Gate Array (FPGA), a processor, a controller, a microprocessor, other electronic unit, or a combination of them, which is designed to perform the above-described functions. In the software implementations, the present invention can be implemented using a module performing the above functions. The software can be stored in a memory unit and executed by a processor. The memory unit or the processor can use various means which are well known to those skilled in the art.
What has been described above includes examples of the various aspects. It is, of course, not possible to describe every conceivable combination of components or methodologies for purposes of describing the various aspects, but one of ordinary skill in the art may recognize that many further combinations and permutations are possible. Accordingly, the subject specification is intended to embrace all such alternations, modifications and variations that fall within the spirit and scope of the appended claims.

Claims

1. A method of controlling uplink transmission power in a wireless communication system, the method comprising:

determining preferentially transmission power of an uplink control channel; and

determining transmission power of an uplink data channel within a difference between maximum transmissible power of a user equipment and the transmission power of the uplink control channel,

wherein an uplink control signal transmitted through the uplink control channel and uplink data transmitted through the uplink data channel are simultaneously transmitted by using different radio resources.

2. The method of claim 1, wherein the transmission power of the uplink control channel is determined by the equation:

P _ctrl=min(P _PSD _— _total ,P _PSD _— _ctrl)

where P_ctrlis to-be-determined transmission power of the uplink control channel, P_PSD _— _totalis a predetermined maximum transmissible power level of the user equipment, and P_PSD _— _ctrlis a temporary transmission power level of the uplink control channel.

3. The method of claim 2, wherein the temporary transmission power level of the uplink control channel is determined by the equation:

P _PSD _— _ctrl(dBm)=L+SINR_Target _— _ctrl+NI+OffsetAMS_perAMS+OffsetABS_perAMS

where P_PSD _— _ctrlis the to-be-determined temporary transmission power level of the uplink control channel, L is an average estimation value of an uplink propagation loss, SINR_Target _— _ctrlis a target signal-to-interference plus noise ratio (SINR) value of the uplink control channel received by a base station, noise and interference (NI) is an average estimation value between noise and an interference level, and OffsetAMS_perAMSand OffsetABS_perAMSare offset values controlled respectively by the user equipment and the base station.

4. The method of claim 1, wherein the transmission power of the uplink control channel is determined by the predetermined transmission power level.

5. The method of claim 4, wherein the transmission power of the uplink control channel is determined to a smaller value between the predetermined transmission power level and a transmission power level calculated by a power control formula.

6. The method of claim 4,

wherein the uplink control channel is divided into a plurality of regions, and

wherein the transmission power level is preferentially determined for a region having a high priority by assigning priorities to the plurality of regions.

7. The method of claim 1, wherein the transmission power of the uplink data channel is determined by the equation:

P _data=min(P _PSD _— _total −P _ctrl ,P _PSD _— _data),

where P_datais to-be-determined transmission power of the uplink data channel, P_PSD _— _totalis a maximum transmissible power level of the user equipment, P_ctrlis transmission power of the uplink control channel, and P_PSD _— _datais a temporary transmission power level of the uplink data channel.

8. The method of claim 7, wherein the temporary transmission power level of the uplink data channel is determined by the equation:

P _PSD _— _data(dBm)=L+SINR_Target _— _data+NI+OffsetAMS_perAMS+OffsetABS_perAMS

where P_PSD _— _datais a to-be-determined temporary transmission power level of the uplink data channel, L is an average estimation value of an uplink propagation loss, SINR_Target _— _datais a target SINR value of the uplink data channel received by a base station, NI is an average estimation value between noise and an interference level, and OffsetAMS_perAMSand OffsetABS_perAMSare offset values controlled respectively by the user equipment and the base station.

9. The method of claim 1, wherein the transmission power of the uplink data channel is determined by a predetermined transmission power level.

10. The method of claim 9, wherein the transmission power of the uplink data channel is determined to a smaller value between the predetermined transmission power level and a transmission power level calculated by a power control formula.

11. The method of claim 1, wherein the uplink control channel and the uplink data channel belong to different regions divided according to a frequency.

12. The method of claim 11, wherein a region to which the uplink control channel belongs is a common region of a cell.

13. The method of claim 12, wherein a region to which the uplink data channel belongs is any one of a part of the common region remaining after the uplink control channel is allocated, an active region, and an inactive region.

14. A user equipment in a wireless communication system, comprising:

a data processor for processing an uplink control signal and uplink data;

a power controller for controlling a power resource to be allocated to an uplink control channel and an uplink data channel; and

a radio frequency (RF) unit for transmitting the uplink control signal through the uplink control channel and for transmitting the uplink data through the uplink data channel,

wherein the power controller determines preferentially transmission power of an uplink control channel, and determines transmission power of an uplink data channel within a difference between maximum transmissible power of a user equipment and the transmission power of the uplink control channel.