WO2010005232A2 - 부분 주파수 재사용 방식을 이용하는 단말의 신호 전송 방법 - Google Patents
부분 주파수 재사용 방식을 이용하는 단말의 신호 전송 방법 Download PDFInfo
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- WO2010005232A2 WO2010005232A2 PCT/KR2009/003727 KR2009003727W WO2010005232A2 WO 2010005232 A2 WO2010005232 A2 WO 2010005232A2 KR 2009003727 W KR2009003727 W KR 2009003727W WO 2010005232 A2 WO2010005232 A2 WO 2010005232A2
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- terminal
- cell
- transmission power
- mcs level
- signal
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04W—WIRELESS COMMUNICATION NETWORKS
- H04W52/00—Power management, e.g. TPC [Transmission Power Control], power saving or power classes
- H04W52/04—TPC
- H04W52/18—TPC being performed according to specific parameters
- H04W52/26—TPC being performed according to specific parameters using transmission rate or quality of service QoS [Quality of Service]
- H04W52/267—TPC being performed according to specific parameters using transmission rate or quality of service QoS [Quality of Service] taking into account the information rate
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04W—WIRELESS COMMUNICATION NETWORKS
- H04W52/00—Power management, e.g. TPC [Transmission Power Control], power saving or power classes
- H04W52/04—TPC
- H04W52/18—TPC being performed according to specific parameters
- H04W52/28—TPC being performed according to specific parameters using user profile, e.g. mobile speed, priority or network state, e.g. standby, idle or non transmission
- H04W52/283—Power depending on the position of the mobile
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04W—WIRELESS COMMUNICATION NETWORKS
- H04W16/00—Network planning, e.g. coverage or traffic planning tools; Network deployment, e.g. resource partitioning or cells structures
- H04W16/24—Cell structures
- H04W16/30—Special cell shapes, e.g. doughnuts or ring cells
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04W—WIRELESS COMMUNICATION NETWORKS
- H04W52/00—Power management, e.g. TPC [Transmission Power Control], power saving or power classes
- H04W52/04—TPC
- H04W52/06—TPC algorithms
- H04W52/14—Separate analysis of uplink or downlink
- H04W52/146—Uplink power control
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04W—WIRELESS COMMUNICATION NETWORKS
- H04W52/00—Power management, e.g. TPC [Transmission Power Control], power saving or power classes
- H04W52/04—TPC
- H04W52/18—TPC being performed according to specific parameters
- H04W52/26—TPC being performed according to specific parameters using transmission rate or quality of service QoS [Quality of Service]
- H04W52/262—TPC being performed according to specific parameters using transmission rate or quality of service QoS [Quality of Service] taking into account adaptive modulation and coding [AMC] scheme
Definitions
- the present invention relates to a terminal and a signal transmission method of the terminal, and more particularly, to a terminal and a method for transmitting the signal in a multi-cell environment using partial frequency reuse.
- Frequency reuse is one of the ways to increase the number of channels per unit area in a cellular system.
- the intensity of the radio wave becomes weaker as the distance increases, and thus the same frequency channel can be used because there is less interference between radio waves at a certain distance or more.
- the same frequency can be used in multiple regions at the same time, greatly increasing subscriber capacity.
- This efficient use of frequency is called frequency reuse.
- a unit for distinguishing regions is called a cell (mobile communication cell), and frequency channel switching between cells for maintaining a call is called handoff.
- frequency reuse is essential.
- Frequency reuse is one of the parameters indicative of frequency efficiency in cellular systems.
- the frequency reuse rate is a value obtained by dividing the total number of cells (sectors) using the same frequency at the same time in the multi-cell structure by the total number of cells (sectors) in the entire multi-cell structure.
- Frequency reuse of 1G systems is less than one.
- the frequency reuse rate is 1/7.
- the frequency reuse rate of 2G systems eg CDMA and TDMA
- the frequency reuse rate can reach 1/4 to 1/3.
- the frequency reuse rate can reach 1, increasing the efficiency of the spectrum and reducing network deployment costs.
- a frequency reuse rate of 1 can be obtained when all sectors within a cell and all cells within a network use the same frequency.
- obtaining a frequency reuse rate of 1 in a cellular network implies that users at the cell's boundary reduce signal reception performance by interference from adjacent cells.
- the boundary area and the center area of the cell are not absolutely defined areas.
- the central area of a cell is close to the base station, which means where users are relatively safe from co-channel interference from adjacent cells, and the internal users in the center of the cell are all available subchannels. Can be used.
- the cell boundary area is where users who are relatively sensitive to interference between adjacent cells are located.
- FFR Fractional Frequency Reuse
- a channel is divided into subchannel units and a signal is transmitted on a subchannel. Accordingly, in a multi-cell environment, internal users at the center of a cell use all available subchannels, while users at adjacent cell boundaries use an FFR that allocates frequencies so that each cell uses a different subchannel.
- control information or a control method for effectively operating FFR includes a base station and a base station. And / or shared between terminals.
- an object of the present invention is to provide a method for efficiently using the FFR in a mobile communication system in a multi-cell environment.
- a method for transmitting a signal by a terminal in a multi-cell environment according to an embodiment of the present invention, according to a specific frequency partition according to a partial frequency reuse scheme from a base station. allocating a frequency partition, receiving Modulation and Coding Scheme (MCS) level information for the specific frequency partition from the base station, wherein the specific frequency partition is located at an adjacent cell boundary If the frequency partition is shared with the terminal, the step of adjusting the transmit power corresponding to the MCS level according to the position in the cell of the terminal and transmitting the signal to the base station with the adjusted transmit power.
- MCS Modulation and Coding Scheme
- the terminal is a terminal located at a cell boundary, and when the MCS level is greater than or equal to a predetermined reference value, the signal may be transmitted using a transmit power higher than the transmit power corresponding to the MCS level.
- the terminal when the terminal is a terminal located at a cell boundary and the MCS level is less than or equal to a predetermined reference value, the terminal may transmit a signal using the maximum transmission power available to the terminal.
- the terminal when the terminal is a terminal located at a cell boundary and the MCS level is greater than or equal to a predetermined reference value, the terminal may transmit a signal using a transmit power lower than the transmit power corresponding to the MCS level.
- the transmission power adjustment may be performed in consideration of interference and path loss.
- a signal may be transmitted using a transmission power higher than the transmission power corresponding to the MCS level.
- the terminal may transmit a signal using a transmit power lower than the transmit power corresponding to the MCS level.
- the frequency partition shared with the terminal located at the adjacent cell boundary is a frequency partition having a frequency reuse rate of 1 and a frequency reuse rate of 1 / n (n is an integer), and the frequency partition is located at an adjacent cell boundary. It may include one or more of the frequency partitions used by one or more terminals.
- a terminal operating in a multi-cell environment for solving the above technical problem is a specific frequency allocated to the terminal according to a fractional frequency reuse scheme from a base station.
- a receiving module for receiving information indicating a frequency partition and modulation and coding scheme (MCS) level information for the specific frequency partition, wherein the specific frequency partition is located at an adjacent cell boundary
- MCS modulation and coding scheme
- the processor for adjusting the transmission power corresponding to the MCS level according to the position of the cell of the terminal and a transmission module for transmitting a signal to the base station with the transmission power adjusted by the processor Include.
- the terminal further includes a memory for storing one or more of information on the modulation and coding scheme corresponding to each MCS level information, first reference value information for the MCS level and second reference value information for the geometric information can do.
- the transmission module when the terminal is a terminal located at a cell boundary and the MCS level is greater than or equal to the first reference value stored in the memory, the transmission module signals using a transmission power higher than the transmission power corresponding to the MCS level. And the processor is a terminal located at a cell boundary, and when the MCS level is less than or equal to the first reference value stored in the memory, the transmission module uses the maximum transmission power available to the terminal. It can be controlled to transmit a signal.
- the transmission module uses a transmission power lower than a transmission power corresponding to the MCS level.
- the processor is configured to transmit a signal, and the processor is a terminal located at a cell boundary, and when the MCS level is less than or equal to the first reference value stored in the memory, the transmission power adjustment may be performed in consideration of interference and path loss. Can be.
- the processor transmits a signal using a transmission power higher than the transmission power corresponding to the MCS level.
- the processor is a terminal located in the center of the cell and has a geometry information value of less than a predetermined reference value.
- the processor transmits a transmission power lower than a transmission power corresponding to the MCS level. It can be controlled to transmit a signal.
- FIG. 1 is a block diagram illustrating an example of a terminal apparatus for transmitting a signal by applying an FFR according to an embodiment of the present invention.
- FIG. 2 is a diagram schematically illustrating a flow of transmitting a signal according to an embodiment of the present invention.
- FIG. 3 is a diagram illustrating a method for allocating a band for each cell by applying an FFR according to an embodiment of the present invention.
- FIG. 4 is a diagram illustrating an example of a cell structure in which a frequency partition is allocated in the FFR application method shown in FIG. 2 in a multi-cell environment.
- FIG. 5 is a diagram illustrating an example of a cell structure in which a frequency partition is allocated without using an FFR according to an embodiment of the present invention.
- FIG. 6 is a diagram showing a frequency full band when no FFR shown in FIG. 5 is used.
- FIG. 7 is a diagram illustrating a method of allocating a band for each cell by applying an FFR according to an embodiment of the present invention.
- FIG. 8 is a diagram illustrating an example of a cell structure in which a frequency partition is allocated in the FFR application method shown in FIG. 7 in a multi-cell environment.
- a base station may be replaced by terms such as a fixed station, a base station, a Node B, an eNode B (eNB), an access point, an ABS, and the like.
- a mobile station may be replaced with terms such as a user equipment (UE), a subscriber station (SS), a mobile subscriber station (MSS), an AMS, or a mobile terminal.
- UE user equipment
- SS subscriber station
- MSS mobile subscriber station
- AMS AMS
- a terminal in uplink, a terminal may be a transmitting end and a base station may be a receiving end.
- a terminal in downlink, a terminal may be a receiving end and a base station may be a transmitting end.
- the terminal of the present invention PDA (Personal Digital Assistant), cellular phone, PCS (Personal Communication Service) phone, GSM (Global System for Mobile) phone, WCDMA (Wideband CDMA) phone, MBS (Mobile Broadband System) phone This can be used.
- PCS Personal Communication Service
- GSM Global System for Mobile
- WCDMA Wideband CDMA
- MBS Mobile Broadband System
- Embodiments of the present invention are provided by standard documents disclosed in at least one of the Institute of Electrical and Electronics Engineers (IEEE) 802 system, 3GPP system, 3GPP LTE (3rd Generation Partnership Project Long Term Evolution) system and 3GPP2 system, which are wireless access systems. Can be supported. That is, steps or parts which are not described to clearly reveal the technical spirit of the present invention among the embodiments of the present invention may be supported by the above documents. In addition, all terms disclosed in the present document can be described by the above standard document. In particular, embodiments of the present invention may be supported by documents such as standard documents of the IEEE 802.16 system, P802.16-2004, P802.16e-2005, and P802.16Rev2.
- each base station uses a different frequency band on a subchannel. For example, some tones are used by all sectors, so the frequency reuse rate is one. On the other hand, the other tones use only 1/3 of each sector, so the frequency reuse rate is 1/3. This frequency reuse rate can be set variously according to the network configuration.
- the power of the terminal may be controlled in consideration of inter-cell interference.
- the performance of the power control of the terminal in consideration of inter-cell interference may be caused by a user or mobile terminal generating or reacting sensitively to ICI between adjacent cells. May be affected by information about For example, the performance of a specific user or a group of users of the system may vary depending on the purpose of implementing inter-cell power control, such as to improve the performance of a user in a specific situation located in a cell boundary region or a cell center region.
- a method capable of limiting or selecting a user or terminal to which inter-cell power control is applied, or a frequency range or time range to an object sensitively or affecting ICI As a method that can be used as a medium for exchanging ICI-related information or user and mobile terminal information between cells, signaling through an air channel or signaling through a backbone network may be considered.
- Determination for power control between cells may be based on path loss, geometry information, signal-to-noise ratio (SINR), etc. in a base station or a scheduler located in the base station.
- SINR signal-to-noise ratio
- FIG. 1 is a block diagram illustrating an example of a terminal apparatus for transmitting a signal by applying an FFR according to an embodiment of the present invention
- Figure 2 is a diagram illustrating a flow of transmitting a signal in the terminal of FIG.
- a terminal operating in a multi-cell environment may transmit a signal through an uplink to a base station using fractional frequency reuse (FFR).
- FFR fractional frequency reuse
- a terminal may include information required from a base station to use FFR, for example, information indicating a specific frequency partition or frequency band allocated to the terminal;
- MCS modulation and coding scheme
- the base station When the terminal transmits a signal to the base station using the FFR, the base station is affected by interference when receiving the transmitted signal according to the multi-user and multi-cell environment requirements in the cell, the reception rate is reduced. Therefore, referring to FIG. 2, in order to efficiently apply FFR, the base station transmits information indicating a specific frequency partition allocated to the terminal and MCS level information to the terminal (S210), and the terminal transmits the received information based on the received information.
- the power may be determined (S220), and a signal may be transmitted to the base station using the determined transmit power (S230).
- the terminal may control the transmission power for efficient FFR, as shown in FIG. 2, the base station receives power control information and MCS level information indicating a specific frequency partition allocated to the terminal to apply the FFR. Alternatively, the control operation may be performed based on the measured information. In this case, when the determination of the transmission power is instructed to the terminal, the terminal performs signal transmission on the uplink according to the received determination.
- a terminal may include information on a modulation and coding scheme corresponding to each MCS level information, first reference value information and geometry information on the MCS level.
- the apparatus may further include a memory 140 that stores one or more of the second reference value information for the.
- the processor 120 derives information on the MCS level, information on the geometry or path loss, and reference value information on the MCS level or the geometry information stored in the memory 140 to determine the transmission power, and assigns a specific frequency to each cell.
- the transmission power may be adjusted according to whether the partition is a frequency partition shared with a terminal located at an adjacent cell boundary.
- the processor 120 adjusts the transmission power according to at least one of the information on the MCS level, geometry or path loss for a particular frequency partition according to the position of the terminal in the cell.
- the geometric information is information indicating a distance between the base station and the terminal, and may be information about the distance between the base station located in one cell or the distance from the base station of another cell when the terminal is a reference.
- the path loss or the geometric information may be transmitted from the base station or measured by the terminal.
- the terminal measures the downlink / uplink, time division duplex (TDD) / frequency division duplex (FDD) Regardless of whether the signal is received from the base station through the downlink is used.
- the downlink signal used to measure such information includes a preamble, a midamble, a common pilot, and the like. Since information is based on long-term geometry, it may have one value per terminal.
- a transmission power control method for reducing ICI performed in a processor for reducing ICI is as follows.
- the FFR in the uplink by controlling the transmission power to reduce the inter-cell interference, it is possible to increase the efficiency of using the FFR.
- FIG. 3 is a diagram illustrating a method of allocating a specific frequency partition for each cell by applying an FFR according to an embodiment of the present invention.
- a user terminal When a user terminal transmits a signal to a base station in a multi-cell environment, users of each cell may be divided into groups to apply FFR.
- the allocation of users to multiple frequency partitions into groups is mainly performed by the base station.
- the terminal receives information about each user group and information about a specific frequency partition assigned to each group from the base station through the receiving module 110.
- user groups are divided and allocated as follows.
- the user group can be largely divided into a first user group having a reuse rate of 1 and a user group having a reuse rate of 1 / n using the same frequency partition in a center region and a boundary region of a cell.
- a user group of 1 / n for example, a user group using a reuse frequency 1/3 frequency partition, has a frequency partition that is the same as a frequency partition assigned to a boundary area of an adjacent cell as a user located in the center area of the cell.
- the second user group may be divided into a third user group using a frequency partition identical to a frequency partition allocated to a center area of an adjacent cell as a user located in a boundary region of a cell. Accordingly, a cell structure for allocating frequency partitions for each cell is shown in FIG. 4.
- a user in the center region or a boundary region of a cell may give an interference effect to a user using the same frequency in an adjacent cell.
- the signal transmission method controls the transmission power in the uplink by dividing the boundary region and the center region of the cell in order to reduce the interference effect and improve user performance.
- the method for controlling the transmission power according to the embodiment of the present invention may use the MCS level of the user.
- the processor 120 transmits a signal of the original terminal to a maximum transmit power that can be used for signal transmission by a cell center region user who uses the same frequency partition as that of the boundary region of an adjacent cell.
- the inter-cell interference effect can be reduced by limiting the transmission power according to the target SINR corresponding to the MCS level lower than the MCS level of the city. For example, when the target SINR of the center region user corresponds to MCS level 6 in the system where the total MCS level is 7, the frequency reuse rate of one cell is 1/3. It is set to transmit power corresponding to the target SINR at MCS level 5 lower than the MCS level. As a result, power used in transmission may be reduced, and thus interference effects to neighboring cells may be reduced.
- the transmission power of the user located in the boundary region in any cell may be limited or arbitrarily increased.
- a user using a frequency partition 2 in cell A 310, a frequency partition 3 in cell B 320, and a frequency partition 4 in cell C 330 may be used by a user in the center region of an adjacent cell.
- High frequency interference can be given to a frequency partition in which the transmit power can be controlled differently according to which area of the cell prioritizes performance improvement.
- the first case is to prioritize the performance improvement of the user in the cell boundary region.
- the processor 120 may have a SINR higher than a target SINR corresponding to the MCS level required for signal transmission by the UE. Set the transmission power accordingly.
- the processor 120 may set the transmission power to be larger than the power according to the target SINR according to the MCS level set when the original signal is transmitted.
- the minimum value of the transmission power may be determined to transmit the minimum transmission power value unconditionally if the calculated transmission power value is less than or equal to the minimum value.
- the processor 120 determines that the transmission power used when transmitting a signal of the UE is high when the MCS level for a specific frequency partition assigned to the cell boundary area user is high.
- the power corresponding to the target SINR lower than the target SINR according to the set MCS level is set.
- the power control may be set lower than the transmission power according to the target SINR according to the originally set MCS level.
- the total MCS level of the user of the boundary area is less than a certain level, such as the case of level 3 or less, the original transmission power adjustment scheme is followed in consideration of interference or path loss.
- a method of controlling transmit power provides a geometric information or a path loss between a base station and a user terminal for a user in a cell center region using the same frequency partition as a frequency partition of a border region of an adjacent cell. Can be based
- inter-carrier interference tends to be inversely proportional to geometric information indicating the distance between the terminal and the base station. That is, if the base station has a high geometric information, the distance between the terminal and the neighboring base station is far, and the interference effect that can be mutually small has a low ICI, but the path loss is large. On the other hand, when the geometry information is small for the base station, the path loss is small because the distance between the terminal and the adjacent base station is short, but may have a high ICI.
- the frequency partition used by the user of the center region of cell A 310 is the frequency partition 3 used in the boundary region of adjacent cell B 320 and the adjacent cell C 330.
- the center The user of the area is set to use a transmission power higher than the preset transmission power. Therefore, the transmission power setting according to the geometry information can be generalized by the following equation (1).
- the processor 120 transmits power when the geometric information of the user is larger than a reference value stored in the memory 140. ) To the preset transmit power ( ) see Set as high as. here, May be arbitrarily set to an amount of power that supplements more than enough power to reduce inter-cell interference.
- a user using a frequency partition having a reuse rate of 1 may set transmission power in consideration of an ICI with a user of a center region of an adjacent cell using a frequency partition having a reuse rate of 1.
- the cell A 310, the cell B 320, and the cell C 330 commonly use frequency partition 1 having a reuse rate of 1, and signal reception performance of the base station is improved due to interference effects between the cells. Can be bad. Accordingly, even in this case, as shown in this case, as shown in this case, as shown in this case, as shown in this case, as shown in this case, as shown in this case, as shown in this case, as shown in this case, as shown in this case, as shown in this case, as shown in this case, as shown in this case, as shown in this case, as shown in this case, as shown in this case, as shown in this case, as shown in this case, as shown in this case, as shown in this case, as shown in this case, as shown in this case, as shown in this case, as shown in Equation 1 or Equation 2,
- the inter-cell power control method according to another embodiment of the present invention may be based on MCS level and geometry information or path loss.
- the MCS level and the geometry information may each have a predetermined reference value, and each reference value may be variously set according to the reuse rate or the user location area in the cell. That is, the reference value is set differently in the reuse rate 1 and reuse rate 1 / N areas, and is set by distinguishing whether the user's position is the central area or the boundary area in one cell of the reuse rate 1 / N.
- the transmission power control according to the present invention can be adjusted according to whether the MCS level and the geometry information satisfy the various predetermined reference values.
- a user uses a frequency partition having a reuse rate of 1 in a center region and a boundary region of a cell.
- the processor 120 adjusts to use the transmission power used when the geometric information of the user who uses the frequency partition having the reuse rate 1 is higher than a reference value when the MCS level is higher than the preset MCS level in the uplink. If the geometric information is lower than the reference value, the signal is transmitted according to the set transmission power.
- the processor 120 sets the transmission power to a power when the target SINR is higher than the target SINR of the set MCS level. do.
- the transmission power is set to a power when the target SINR is lower than the target SINR of the set MCS level.
- the transmission power is set to the maximum transmit power (full Tx power) available to the terminal.
- the transmission power control method for reducing ICI and increasing reception performance when applying FFR in the uplink is described above.
- the user terminal may transmit a signal to the base station according to the determined transmission power.
- the terminal transmits a signal using the transmission power corresponding to the reference value, thereby reducing the transmission rate to a predetermined level or less. Can be prevented.
- the method for adjusting the transmission power according to the embodiment of the present invention described above uses not only the FFR method of dividing and allocating users to a plurality of specific frequency partitions, but also has one frequency partition regardless of a specific region of a cell. This may also apply.
- FFR can be applied to downlink as well as uplink, in order to reduce inter-cell interference with neighboring cells, whether to implement FFR, the number of bands used for FFR, bandwidth, frequency reuse factor for FFR And so on.
- the FFR setting method is to minimize the control signal that increases as the information exchange rate between adjacent cells increases due to the above various determinations, and efficiently perform the FFR.
- Table 1 A description with reference to Table 1 below.
- Table 1 shows an example of the FFR setting method according to an embodiment of the present invention.
- Table 1 shows a number of user partition (or grouping), frequency reuse factor (FRF), BW partition, transmit power level (for downlink), and a signaling format for indicating the FFR.
- FFR frequency reuse factor
- BW partition transmit power level
- signaling format for indicating the FFR.
- the determination of FFR is used as shown in Table 1 above. For example, assuming that the signaling bit is 2 bits, the signaling indication may be 00 when no FFR is applied, and the signaling indication may be 01, 10, or 11 when FFR is applied.
- the signaling bit is 2 bits, if the signaling type is expressed as 00, this may indicate that the FRR is not applied. Since the same frequency partition is used for the cell's center region and border region, the FRF, Number of user partition is 1, BW is the bandwidth BW T according to system performance, and the transmit power level used in downlink is 1. Can be. In Table 1, P 1 represents power level 1 (P1 level) and can be determined according to system performance. As such, when the FFR is not used, cells may be configured and frequency partitions may be allocated as shown in FIGS. 5 and 6.
- FIG. 5 is a diagram illustrating an example of a cell structure in which a frequency partition is allocated without using an FFR in a multi-cell environment according to an embodiment of the present invention.
- the frequency band is divided into four frequency partitions, if the FFR is not used, all the cells are not divided into the center region or the boundary region but four frequency partitions (1, 2, 3, 4) divided over the entire region of the cell.
- the entire frequency band as shown in FIG. 6 may be the bandwidth of the system.
- the transmit power of the base station may be used equally to all users at the P1 level.
- the 2-bit signaling indication is not 00, it may be indicated to perform FFR.
- Limits are considered in consideration of the increase in the control signal and the efficiency of the FFR or the complexity of the FFR operation. You can put it.
- FIG. 3 and 4 illustrate the application of an FFR according to an embodiment of the present invention, and in the case of FRF 1/3, a frequency partition is allocated to each cell.
- 7 and 8 are diagrams illustrating frequency partition allocation for each cell when FRF 2/3 is applied to another FFR according to an embodiment of the present invention.
- the frequency partitions 2, 3, and 4 correspond to frequencies corresponding to 1/3 of the reuse rate.
- Partitions can have the same ratio BW of 1: 1: 1.
- the ratio of band 1: band (2 + 3 + 4) may vary.
- x is frequency partition 1 assigned to the cell region of the reuse rate 1 in FIG. Two bits of signaling bits are used for BW partiton indication.
- a user group located in the center region of the cell, the second user group using the same frequency partition as the frequency partition allocated to the boundary region of the adjacent cell, A third user group using the same frequency partition as the frequency partition allocated to the center region of the adjacent cell as a user located in the boundary region of the cell, and a frequency partition assigned to the boundary region of the neighbor cell as a user located in the boundary region of the cell Can be divided into a fourth user group using the same frequency partition.
- the fourth user group may appear when using a frequency partition having a reuse rate of 2/3.
- a user using frequency partition 1 is a first user group
- a user using frequency partitions 3 and 4 is a second user group and a frequency partition.
- the user using 2 corresponds to the third user group.
- a user who uses frequency partition 1 may have a first user group in a relationship with neighbor cells B 420 and C 430.
- User using frequency partition 4 uses a second user group in relation to neighbor cell B 420
- user using frequency partition 2 uses a third user group in frequency relation with neighbor cell B 420, frequency partition 3.
- the user corresponds to the fourth user group in relation to the neighbor cell B 420.
- the user using each frequency partition corresponds to User groups are different. That is, it can be regarded as a relative classification according to the relationship with the adjacent cells.
- power control may be performed for each band. At this time, it can be set to the power level 1 (P1 value), which requires separate signaling.
- P1 value which requires separate signaling.
- separate signaling is required in case of changing the bandwidth of the frequency reuse range defined between each cell. In this case, it may be indicated through signaling indication such as 11 that there is separate signaling using 2 bit signaling.
- the base station may set an efficient FFR based on various determined matters and transmit a signal to the user, or instruct the plurality of users who transmit and receive signals with the base station to use the set FFR decision.
- Information such as geometry information or path loss required to configure the FFR may be obtained by the base station or reported from the terminal as described above.
- the UE can measure path loss or geometry information using a downlink signal and report it to the base station.
- information for inter-cell power control for example, modulation and coding scheme (MCS) : Modulation and Coding Scheme) level information, which can be obtained and reported to the base station.
- MCS modulation and coding scheme
- the UE may report the measured information to the base station in a period not greater than the dynamic period of the FFR.
- the FFR dynamic period refers to a period in which the inter-cell FFR configuration, the number of FFR groups, and the bandwidth and power level of each group are changed in common.
- the terminal may report to the base station at a period not smaller than the period measured by the terminal.
- the base station determines whether the FFR is implemented, the number of bands used for the FFR, the bandwidth, the FRF, and the like, based on the information reported from the terminal, and transmits a signal to the terminal using the determined FFR.
- inter-cell power control according to an embodiment of the present invention may be used to reduce the effects of inter-cell interference (ICI) and to improve the performance of a specific user or system. .
- ICI inter-cell interference
- information acquisition for inter-cell power control should be selected from the subject.
- a method of selecting a user or a mobile terminal to obtain necessary information may vary.
- a mobile terminal is selected based on a base station located in a serving cell. Based on the path loss, the geometry information, the received SINR, etc., a user or a terminal having a value below or above a predetermined threshold may be selected. Alternatively, a user may be selected to apply inter-cell power control according to a preset ratio among a plurality of users.
- a mobile terminal is selected based on a base station included in a neighboring cell.
- a user generating strong ICI as a base station included in a neighbor cell may be selected as a user performing inter-cell power control.
- the first case is based on information obtained from communication through a backbone between a base station of a serving cell and a base station of a neighboring cell.
- a serving base station receives information from a neighboring cell base station and uses the same resource for a resource region that receives strong ICI, such as a frequency band according to subchannelization, a resource block, a subchannel, etc. May select a user scheduled to be scheduled.
- the second case is based on information obtained through a radio channel between a terminal of an arbitrary cell and a base station of a neighbor cell.
- Received signals for example, preambles
- neighbor cells obtained by a user or a mobile terminal using signals used for handover and handover or signals used for scanning and scanning, or performing cell search
- it may be determined whether or not strong interference may be caused to an adjacent cell based on a known signal) size, a path loss, a geometry, a signal transmission delay time, and the like, and may be reported to the serving cell.
- the acquired information may be reported to the serving cell to determine whether the user can generate strong ICI in the serving cell, and to select the selected cell.
- a user of each cell receives a signal from a neighboring cell to measure information or strength of the signal. The user may be selected by determining whether to perform power control between cells.
- the subject that acquires the information is selected, and if the subject has obtained the information, it should be reported so that the base station can set the FFR.
- a method of reporting information obtained from a serving cell or neighbor cells to a base station included in the serving cell will be described in detail.
- the user terminal reports the information obtained from the base station of the neighboring cell or the neighboring cell from the neighboring cells to the base station of the serving cell.
- the terminal reports to the base station using the uplink, there are various methods.
- the terminal reports to the base station using the uplink reporting channel of the existing system.
- the terminal may request for handover, handover notification, and scanning.
- Information obtained by modifying an existing uplink channel may be reported to a base station of a serving cell.
- the UE reports information related to inter-cell interference to a base station of a serving cell by using a new signal and report channel.
- a new report signal format A report signal format and a report channel can be used.
- the transmission period of the reported information may be an N multiple (periodic report) of the inter-cell power control period or may be made aperiodic report according to the determination of the base station and the user terminal of the serving cell.
- the BS may determine the type of FFR to be used to reduce interference between adjacent cells in the multi-cell environment.
- each component or feature is to be considered optional unless stated otherwise.
- Each component or feature may be embodied in a form that is not combined with other components or features. It is also possible to combine some of the components and / or features to form an embodiment of the invention.
- the order of the operations described in the embodiments of the present invention may be changed. Some components or features of one embodiment may be included in another embodiment or may be replaced with corresponding components or features of another embodiment. It is obvious that the claims may be combined to form an embodiment by combining claims that do not have an explicit citation relationship in the claims or as new claims by post-application correction.
- Embodiments according to the present invention may be implemented by various means, for example, hardware, firmware, software, or a combination thereof.
- an embodiment of the present invention may include one or more Application Specific Integrated Circuits (ASICs), Digital Signal Processors (DSPs), Digital Signal Processing Devices (DSPDs), Programmable Logic Devices (PLDs), FPGAs ( Field Programmable Gate Arrays), processors, controllers, microcontrollers, microprocessors, and the like.
- ASICs Application Specific Integrated Circuits
- DSPs Digital Signal Processors
- DSPDs Digital Signal Processing Devices
- PLDs Programmable Logic Devices
- FPGAs Field Programmable Gate Arrays
- processors controllers, microcontrollers, microprocessors, and the like.
- an embodiment of the present invention may be implemented in the form of a module, procedure, function, etc. that performs the functions or operations described above.
- the software code may be stored in a memory unit and driven by a processor.
- the memory unit may be located inside or outside the processor, and may exchange data with the processor by various known means.
- the present invention allows a terminal using partial frequency reuse in a multi-cell environment to more efficiently use partial frequency reuse.
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Abstract
Description
Claims (14)
- 다중 셀 환경의 단말이 신호를 전송하는 방법에 있어서,기지국으로부터 부분 주파수 재사용 방식(fractional frequency reuse)에 따라 특정 주파수 파티션(frequency partition)을 할당받는 단계;상기 기지국으로부터 상기 특정 주파수 파티션 또는 특정 주파수 파티션내의 특정 자원 영역에 대한 변조 및 코딩 방식(MCS: Modulation and Coding Scheme) 레벨 정보를 수신하는 단계;상기 특정 주파수 파티션(frequency partition)이 인접 셀 경계에 위치하는 단말과 공유되는 주파수 파티션인 경우, 상기 단말의 셀 내 위치에 따라 상기 MCS 레벨에 대응하는 전송 전력을 조정하는 단계; 및상기 조정된 전송 전력으로 상기 기지국에 신호를 전송하는 단계를 포함하는, 신호 전송 방법.
- 제 1 항에 있어서,상기 단말이 셀 경계에 위치하는 단말이며, 상기 MCS 레벨이 소정 기준치 이상인 경우,상기 MCS 레벨에 대응하는 전송 전력보다 높은 전송 전력을 이용하여 신호를 전송하는, 신호 전송 방법.
- 제 1 항에 있어서,상기 단말이 셀 경계에 위치하는 단말이며, 상기 MCS 레벨이 소정 기준치 이하인 경우,상기 단말이 이용 가능한 최대 전송 전력을 이용하여 신호를 전송하는, 신호 전송 방법.
- 제 1 항에 있어서,상기 단말이 셀 경계에 위치하는 단말이며, 상기 MCS 레벨이 소정 기준치 이상인 경우,상기 MCS 레벨에 대응하는 전송 전력보다 낮은 전송 전력을 이용하여 신호를 전송하는, 신호 전송 방법.
- 제 1 항에 있어서,상기 단말이 셀 경계에 위치하는 단말이며, 상기 MCS 레벨이 소정 기준치 이하인 경우,간섭 및 경로 손실을 고려하여 상기 전송 전력 조정을 수행하는, 신호 전송 방법.
- 제 1 항에 있어서,상기 단말이 셀 중심부에 위치하는 단말이고, 소정 기준치 이상의 기하학(geometry) 정보 값을 가지는 경우,상기 MCS 레벨에 대응하는 전송 전력보다 높은 전송 전력을 이용하여 신호를 전송하는, 신호 전송 방법.
- 제 1 항에 있어서,상기 단말이 셀 중심부에 위치하는 단말이고, 소정 기준치 이하의 기하학(geometry) 정보 값을 가지는 경우,상기 MCS 레벨에 대응하는 전송 전력보다 낮은 전송 전력을 이용하여 신호를 전송하는, 신호 전송 방법.
- 제 1 항에 있어서,상기 조정된 전송 전력이 소정 기준치 이하인 경우, 기준치에 해당하는 전송 전력을 이용하여 신호를 전송하는, 신호 전송 방법
- 제 8 항에 있어서,상기 인접 셀 경계에 위치하는 단말과 공유되는 주파수 파티션은, 주파수 재사용율이 1인 주파수 파티션 및 주파수 재사용율이 1/n이고(n은 정수), 해당 주파수 파티션이 인접 셀 경계에 위치하는 하나 이상의 단말에 의해 사용되는 주파수 파티션 중 하나 이상을 포함하는, 신호 전송 방법.
- 다중 셀 환경에서 동작하는 단말에 있어서,기지국으로부터 부분 주파수 재사용 방식(fractional frequency reuse)에 따라 상기 단말에 할당되는 특정 주파수 파티션(frequency partition)을 나타내는 정보, 및 상기 특정 주파수 파티션에 대한 변조 및 코딩 방식(MCS: Modulation and Coding Scheme) 레벨 정보를 수신하는 수신 모듈;상기 특정 주파수 파티션(frequency partition)이 인접 셀 경계에 위치하는 단말과 공유되는 주파수 파티션인 경우, 상기 단말의 셀 내 위치에 따라 상기 MCS 레벨에 대응하는 전송 전력을 조정하는 프로세서; 및상기 프로세서에 의해 조정된 전송 전력으로 상기 기지국에 신호를 전송하는 전송 모듈을 포함하는, 단말.
- 제 10 항에 있어서,상기 단말은 각 MCS 레벨 정보에 대응하는 변조 및 코딩 방식에 대한 정보, 상기 MCS 레벨에 대한 제 1 기준치 정보 및 기하학 정보에 대한 제 2 기준치 정보 중 하나 이상을 저장하는 메모리를 더 포함하는, 단말.
- 제 10 항에 있어서,상기 프로세서는 상기 단말이 셀 경계에 위치하는 단말이며 상기 MCS 레벨이 상기 메모리에 저장된 상기 제 1 기준치 이상인 경우, 상기 전송 모듈이 상기 MCS 레벨에 대응하는 전송 전력보다 높은 전송 전력을 이용하여 신호를 전송하도록 제어하며,상기 프로세서는 상기 단말이 셀 경계에 위치하는 단말이며, 상기 MCS 레벨이 상기 메모리에 저장된 상기 제 1 기준치 이하인 경우, 상기 전송 모듈이 상기 단말이 이용 가능한 최대 전송 전력을 이용하여 신호를 전송하도록 제어하는, 단말.
- 제 10 항에 있어서,상기 프로세서는 상기 단말이 셀 경계에 위치하는 단말이며, 상기 MCS 레벨이 상기 메모리에 저장된 상기 제 1 기준치 이상인 경우, 상기 전송 모듈이 상기 MCS 레벨에 대응하는 전송 전력보다 낮은 전송 전력을 이용하여 신호를 전송하도록 제어하며,상기 프로세서는 상기 단말이 셀 경계에 위치하는 단말이며, 상기 MCS 레벨이 상기 메모리에 저장된 상기 제 1 기준치 이하인 경우, 간섭 및 경로 손실을 고려하여 상기 전송 전력 조정을 수행하는, 단말.
- 제 10 항에 있어서,상기 프로세서는 상기 단말이 셀 중심부에 위치하는 단말이고, 소정 기준치 이상의 기하학(geometry) 정보 값을 가지는 경우, 상기 전송 모듈이 상기 MCS 레벨에 대응하는 전송 전력보다 높은 전송 전력을 이용하여 신호를 전송하도록 제어하며,상기 프로세서는 상기 단말이 셀 중심부에 위치하는 단말이고, 소정 기준치 이하의 기하학(geometry) 정보 값을 가지는 경우, 상기 전송 모듈이 상기 MCS 레벨에 대응하는 전송 전력보다 낮은 전송 전력을 이용하여 신호를 전송하도록 제어하는, 단말.
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US8358619B2 (en) * | 2008-07-25 | 2013-01-22 | Lg Electronics Inc. | Mobile station apparatus and method for transmitting signals in wireless communication system |
US8565210B2 (en) * | 2008-08-27 | 2013-10-22 | Lg Electronics Inc. | Apparatus for transmitting a signal in wireless communication system and method for same |
KR101608784B1 (ko) * | 2009-01-21 | 2016-04-20 | 엘지전자 주식회사 | 무선 통신 시스템에서의 멀티캐스트 및/또는 브로드캐스트 서비스 데이터를 위한 자원 할당 방법 및 이를 위한 장치 |
US9078220B2 (en) | 2013-09-27 | 2015-07-07 | Motorola Solutions, Inc. | Method and apparatus for UE power class adaption for coverage extension in LTE |
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