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WO2016122112A1 - Procédé et dispositif destinés à l'estimation de l'affaiblissement de propagation dans un système de communication sans fil prenant en charge un laa - Google Patents

Procédé et dispositif destinés à l'estimation de l'affaiblissement de propagation dans un système de communication sans fil prenant en charge un laa Download PDF

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Publication number
WO2016122112A1
WO2016122112A1 PCT/KR2015/013598 KR2015013598W WO2016122112A1 WO 2016122112 A1 WO2016122112 A1 WO 2016122112A1 KR 2015013598 W KR2015013598 W KR 2015013598W WO 2016122112 A1 WO2016122112 A1 WO 2016122112A1
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Prior art keywords
serving cell
path loss
terminal
unlicensed band
secondary serving
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English (en)
Korean (ko)
Inventor
박동현
권기범
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ITL Inc
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ITL Inc
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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B7/00—Radio transmission systems, i.e. using radiation field
    • H04B7/24—Radio transmission systems, i.e. using radiation field for communication between two or more posts
    • H04B7/26—Radio transmission systems, i.e. using radiation field for communication between two or more posts at least one of which is mobile
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B17/00—Monitoring; Testing
    • H04B17/30—Monitoring; Testing of propagation channels
    • H04B17/309—Measuring or estimating channel quality parameters
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B17/00—Monitoring; Testing
    • H04B17/30—Monitoring; Testing of propagation channels
    • H04B17/309—Measuring or estimating channel quality parameters
    • H04B17/347—Path loss
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B7/00—Radio transmission systems, i.e. using radiation field
    • H04B7/24—Radio transmission systems, i.e. using radiation field for communication between two or more posts
    • H04B7/26—Radio transmission systems, i.e. using radiation field for communication between two or more posts at least one of which is mobile
    • H04B7/2603—Arrangements for wireless physical layer control

Definitions

  • the present invention relates to a method and apparatus for estimating path-loss in a wireless communication system supporting Licensed Assisted Access (LAA).
  • LAA Licensed Assisted Access
  • Cellular is a concept proposed to overcome the limitations of service area, frequency, and subscriber capacity, and it is possible to reuse frequency spatially by dividing mobile service area into several small cells. .
  • a particular area such as a hotspot inside a cell
  • reception sensitivity of radio waves may be reduced.
  • small cells such as pico cells and femto cells
  • a micro cell, a remote radio head (RRH), a relay, a repeater, and the like are installed together.
  • RRH remote radio head
  • Such a network is called a heterogeneous network (HetNet).
  • HetNet heterogeneous network
  • a macro cell is a large coverage cell
  • a small cell such as a femto cell and a pico cell is a small coverage cell.
  • CA carrier aggregation
  • the serving cell set on the unlicensed band can be easily exposed to interference due to the nature of the unlicensed band, thereby providing reliable path-loss. It is impossible to estimate. This causes uplink transmission power control based on inaccurate path loss values, which not only degrades the performance of the entire system but can also cause unnecessary interference.
  • An object of the present invention is to provide a reliable method and apparatus for estimating path loss in a wireless communication system in which carrier aggregation is configured between a serving cell of a licensed band and a serving cell of an unlicensed band.
  • Another object of the present invention is to provide a method and apparatus for configuring and transmitting information for estimating a path loss for a serving cell of an unlicensed band in a wireless communication system configured with carrier aggregation.
  • a method for estimating a path loss in a wireless communication system includes a terminal configured with carrier aggregation between a serving cell of a licensed band and a serving cell of an unlicensed band from an eNB to an RRC Receiving a Radio Resource Control) message and estimating a path loss during uplink transmission through a secondary serving cell configured in the unlicensed band based on information on a path loss reference serving cell included in the RRC message.
  • a terminal configured with carrier aggregation between a serving cell of a licensed band and a serving cell of an unlicensed band from an eNB to an RRC Receiving a Radio Resource Control) message and estimating a path loss during uplink transmission through a secondary serving cell configured in the unlicensed band based on information on a path loss reference serving cell included in the RRC message.
  • a terminal configured with carrier aggregation between a serving cell of a licensed band and a serving cell of an unlicensed band is selected from among secondary serving cells of the unlicensed band based on channel acquisition. Dynamically selecting one and estimating a path loss during uplink transmission through the secondary serving cell configured in the unlicensed band based on the selected secondary serving cell.
  • a path loss estimation method in a wireless communication system is a channel environment of a terminal of a terminal based on a signal received from a terminal configured with carrier aggregation between a serving cell of a licensed band and a serving cell of an unlicensed band. Estimating, determining whether to change the path loss reference serving cell of the terminal based on the estimated channel environment, and if the path loss reference serving cell is changed, determining the path loss reference serving cell to the terminal.
  • the method may include transmitting an RRC message indicating a change of.
  • a terminal configured with carrier aggregation between a licensed band serving cell and an unlicensed band serving cell is included in an RF (Radio Frequency) unit for receiving an RRC message from a base station and the RRC message.
  • RF Radio Frequency
  • the present invention can reliably estimate path loss even when carrier aggregation is configured between a serving cell of a licensed band and a serving cell of an unlicensed band.
  • by transmitting and receiving information for estimating a path loss for the unlicensed band between the serving cell of the licensed band and the serving cell of the unlicensed band it provides an advantage of guaranteeing the overall quality of service through the unlicensed band.
  • FIG. 1 shows a wireless communication system to which the present invention is applied.
  • FIG. 2 shows examples of a LAA deployment scenario to which the present invention is applied.
  • FIG. 3 is an exemplary diagram illustrating a case where an existing path loss estimation method is applied to a situation in which carrier aggregation between a serving cell of a licensed band and a serving cell of an unlicensed band is configured.
  • 4 and 5 are diagrams illustrating an example of an interference situation when carrier aggregation between a serving cell of a licensed band and a serving cell of an unlicensed band is configured.
  • FIG. 6 illustrates a path loss estimation method according to an embodiment of the present invention.
  • FIG. 7 is a flowchart illustrating the operation of a terminal according to an embodiment of the present invention.
  • FIG. 8 is a flowchart illustrating the operation of a base station according to an embodiment of the present invention.
  • FIG 9 illustrates a path loss estimation method according to another embodiment of the present invention.
  • FIG. 10 is a flowchart illustrating the operation of a terminal according to another embodiment of the present invention.
  • FIG. 11 is a block diagram illustrating a wireless communication system according to an embodiment of the present invention.
  • the present specification describes a wireless communication network
  • the operation performed in the wireless communication network is performed in the process of controlling the network and transmitting data in the system (for example, the base station) that is in charge of the wireless communication network, or the corresponding wireless Work may be done at the terminal coupled to the network.
  • FIG. 1 shows a wireless communication system to which the present invention is applied.
  • the network structure shown in FIG. 1 may be a network structure of an Evolved-Universal Mobile Telecommunications System (E-UMTS).
  • E-UMTS Evolved-Universal Mobile Telecommunications System
  • the E-UMTS system may include a Long Term Evolution (LTE), an LTE-A (Advanced) system, and the like.
  • Wireless communication systems are widely deployed to provide various communication services such as voice, packet data, and the like.
  • CDMA Code Division Multiple Access
  • TDMA Time Division Multiple Access
  • FDMA Frequency Division Multiple Access
  • OFDMA Orthogonal Frequency Division Multiple Access
  • SC-FDMA Single Carrier-FDMA
  • OFDM-FDMA OFDM-TDMA
  • various multiple access schemes such as OFDM-CDMA may be used.
  • the E-UTRAN includes at least one base station (BS) 20 that provides a control plane and a user plane to the terminal.
  • the UE 10 may be fixed or mobile and may have other mobile stations, advanced MSs (AMS), user terminals (UTs), subscriber stations (SSs), wireless devices (Wireless Devices), and the like. It may be called a term.
  • the base station 20 generally refers to a station communicating with the terminal 10, and includes an evolved-NodeB (eNB), a base transceiver system (BTS), an access point, and a femto-eNB. ), A pico base station (pico-eNB), a home base station (Home eNB), relay (relay) may be called other terms.
  • the base station 20 may provide at least one cell to the terminal.
  • the cell may mean a geographic area where the base station 20 provides a communication service or may mean a specific frequency band.
  • the cell may mean a downlink frequency resource and an uplink frequency resource. Alternatively, the cell may mean a combination of a downlink frequency resource and an optional uplink frequency resource.
  • CA carrier aggregation
  • the source base station (Source BS) 21 refers to a base station in which a radio bearer is currently set up with the terminal 10, and the target base station (Target BS, 22) means that the terminal 10 disconnects the radio bearer from the source base station 21 and renews it. It means a base station to be handed over to establish a radio bearer.
  • the base stations 20 may be connected to each other through an X2 interface.
  • the X2 interface is used to send and receive messages between the base stations 20.
  • the base station 20 is connected to an evolved packet system (EPS), more specifically, a mobility management entity (MME) / serving gateway (S-GW) 30 through an S1 interface.
  • EPS evolved packet system
  • MME mobility management entity
  • S-GW serving gateway
  • the S1 interface supports a many-to-many-relation between base station 20 and MME / S-GW 30.
  • the PDN-GW 40 is used to provide packet data services to the MME / S-GW 30.
  • downlink means communication from the base station 20 to the terminal 10
  • uplink means communication from the terminal 10 to the base station 20.
  • the downlink is also called a forward link
  • the uplink is also called a reverse link.
  • the transmitter may be part of the base station 20 and the receiver may be part of the terminal 10.
  • the transmitter may be part of the terminal 10 and the receiver may be part of the base station 20.
  • a time division duplex (TDD) scheme using different times may be used as an uplink transmission and a downlink transmission scheme, or a frequency division duplex (FDD) scheme using different frequencies may be used. Can be used.
  • TDD time division duplex
  • FDD frequency division duplex
  • carrier aggregation supports a plurality of carriers and is also referred to as spectrum aggregation or bandwidth aggregation.
  • Individual unit carriers bound by carrier aggregation are called component carriers (CC).
  • Each component carrier is defined by a bandwidth and a center frequency. For example, if five component carriers are allocated as granularity in a carrier unit having a 20 MHz bandwidth, a bandwidth of up to 100 MHz may be supported.
  • a serving cell may be defined as an element frequency band that may be aggregated by a CA based on a multiple component carrier system.
  • the serving cell includes a primary serving cell (PCell) and a secondary serving cell (SCell).
  • the primary serving cell is one that provides security input and non-access stratum (NAS) mobility information in a radio resource control (RRC) connection or re-establishment state. It means a serving cell.
  • RRC radio resource control
  • at least one cell may be configured to form a set of serving cells together with the main serving cell, wherein the at least one cell is called a secondary serving cell.
  • the set of serving cells configured for one terminal may consist of only one main serving cell or one main serving cell and at least one secondary serving cell. Each serving cell may be operated in an activated or deactivated state.
  • FIG. 2 shows examples of a LAA deployment scenario to which the present invention is applied.
  • the wireless system utilizes the frequencies of the licensed band as well as the unlicensed band that the WiFi system is using. Methods of conducting communication are under discussion.
  • wireless communication in the unlicensed band may be provided with the support of the communication technique of the licensed band.
  • LAA License Assisted Access
  • LAA supports CA operation for one or more secondary serving cells operating in an unlicensed band or unlicensed spectrum based on the assistance of a primary serving cell operating in a licensed band or spectrum.
  • a wireless communication scheme is shown.
  • LAA is a technology that binds a licensed band and an unlicensed band to one using a CA as an anchor and a licensed band as an anchor.
  • the licensed band may be used as the primary serving cell and the unlicensed band may be used as the secondary serving cell.
  • the unlicensed band may be activated only through the CA and may not perform LTE communication alone.
  • the terminal accesses the network through the licensed band to use the service, and the base station combines the licensed band and the unlicensed band into the CA through an RRC resetting process according to circumstances, thereby offloading the traffic of the licensed band to the unlicensed band. You can.
  • Scenario 1 is a case where a macro cell using a licensed carrier F1 (frequency 1) and a small cell using an unlicensed carrier F3 are connected by carrier aggregation (CA).
  • Scenario 2 is a case where the small cell # 1 using the licensed carrier F2 and the small cell # 2 using the unlicensed carrier F3 are connected by carrier aggregation in addition to the macro cell coverage.
  • Scenario 3 is a case where there is a macro cell using a licensed carrier F1 and a small cell # 1, and the small cell # 1 is connected to the carrier aggregation through F1 and F2 carrier by additionally using an unlicensed carrier F3.
  • Scenario 4 is a situation where there is a macro cell using a licensed carrier F1, a small cell # 1 using a licensed carrier F2 and an unlicensed carrier F3.
  • carrier aggregation may be set using F1, F2, and F3. If dual-connectivity is set using F1 and F2, carrier aggregation may be additionally set using F2 and F3.
  • each serving cell in the licensed band and the unlicensed band has a time alignment group (TAG) according to the band in which it is located.
  • TAG time alignment group
  • the TAG is a group including serving cell (s) using the same time forward value and the same timing reference or the timing reference cell including the timing reference among uplink configured serving cells.
  • the TAG is divided into a primary timing alignment group (P-TAG) and a secondary timing alignment group (S-TAG).
  • P-TAG is a TAG including a primary serving cell
  • the S-TAG is a TAG composed of only secondary serving cells.
  • the primary serving cell may be configured only on the licensed band.
  • an uplink component carrier (UL SCC) of a secondary serving cell belongs to a P-TAG in a wireless communication system
  • the base station uses RRC signaling to downlink component carrier (DL PCC) of the primary serving cell or UL of the secondary serving cell.
  • DL PCC downlink component carrier
  • the UE provides a configuration of a path-loss reference serving cell for the UL SCC among DL SCCs having an SCC and SIB2 (System Information Block 2) linkage. All secondary serving cells (eg, secondary serving cells belonging to the S-TAG) without this configuration estimate path loss based on the DL CC having the corresponding UL CC and SIB2 connection.
  • the UL PCC always estimates the path loss based on the DL PCC.
  • the SIB2 is information provided to allow the terminal to access the cell and includes an uplink cell bandwidth, a random-access parameter, and parameters related to uplink power control.
  • RRC signaling for UL SCC is that in some heterogeneous network (HetNet) environments, reliable path loss estimation is not possible on DL SCCs of small cells that may be strongly interfered with from macro cells. .
  • HetNet heterogeneous network
  • terminals in the small cell can estimate the path loss of the UL SCC based on the DL PCC, thereby enabling more reliable path loss estimation.
  • the wireless communication system currently supports CA between up to five CCs, but in the 5 GHz band where LAA is being considered, a greater number of CCs (eg, up to 32 CCs) may be used. CA may be considered.
  • a local area network (LAN) system such as WiFi can provide 80 MHz and 160 MHz bands, and thus a wireless communication system such as LTE also needs to provide a similar or higher frequency concatenation.
  • the wireless communication system may additionally provide one or more carriers to the existing band even in the licensed 3.5 GHz band, it is necessary to provide a function capable of concatenating five or more component carriers at least in downlink.
  • the overhead on the primary serving cell on which the Physical Uplink Control CHannel (PUCCH) is transmitted may become even larger in the situation of configuring CA between a large number of carriers as well as the present. Accordingly, in order to solve this problem, PUCCH transmission on a secondary serving cell may be considered.
  • PUCCH transmission on a secondary serving cell may be considered. This is not only an overhead problem, but in a situation in which a remote radio head (RRH) as in Scenario 4 is considered, the utilization of RRH is distributed depending on the main serving cell without depending on the operation of changing the main serving cell. You can.
  • RRH remote radio head
  • the serving cell set on the unlicensed band may be easily exposed to interference due to the nature of the unlicensed band. This makes it impossible to estimate a reliable path-loss. It causes uplink transmit power control based on incorrect path loss values, which not only degrades the performance of the entire system but can also cause unnecessary interference. Therefore, there is a need for a method for reliably estimating path loss in a situation where a CA is configured between a serving cell of a licensed band and a serving cell of an unlicensed band.
  • FIG. 3 is an exemplary diagram illustrating a case where an existing path loss estimation method is applied to a situation in which carrier aggregation between a serving cell of a licensed band and a serving cell of an unlicensed band is configured.
  • a primary serving cell (PCell) and two secondary serving cells (SCell # 1 and SCell # 2) are configured in a licensed band (L-band), and three subbands are provided in an unlicensed band (U-band).
  • the case where the serving cells SCell # 3, SCell # 4 and SCell # 5 are configured is shown.
  • a plurality of TAGs Multiple-TAGs
  • -TAG can be set.
  • DL SCCs (DL CCs of SCell # 3, SCell # 4 and SCell # 5) set on the unlicensed band are more than DL SCCs (DL CCs of SCell # 1 and SCell # 2) set on the licensed band.
  • DL SCCs (DL CCs of SCell # 1 and SCell # 2) set on the licensed band.
  • a DL SCC (DL of SCell # 1 and SCell # 2) in which a path loss reference serving cell of an UL SCC (UL CC of SCell # 1 and SCell # 2) set on a licensed band due to interference in a specific environment is connected to SIB2.
  • the DL SCCs (DL CCs of SCell # 3, SCell # 4 and SCell # 5) on the unlicensed band are in a worse channel environment.
  • secondary serving cells on the unlicensed band may be exposed to interference as shown in FIG. 4.
  • 4 and 5 are diagrams illustrating an example of an interference situation when carrier aggregation between a serving cell of a licensed band and a serving cell of an unlicensed band is configured.
  • a carrier configured between a serving cell and a serving cell of an unlicensed band (hereinafter referred to as a LAA terminal) experiences interference from a hidden node.
  • the unlicensed band allows a base station or a terminal to acquire a channel access opportunity based on competition.
  • the channel access mechanism provides opportunistic channel access.
  • a wireless communication device such as a base station or an access point (AP) may perform a clear channel assessment (CCA) or extended clear channel assessment (ECCA) before using a corresponding channel.
  • CCA clear channel assessment
  • ECCA extended clear channel assessment
  • eNBs LAA base stations
  • WLAN Wireless Local Area Network
  • CCA or ECCA is a procedure for determining whether the channel is occupied or unoccupied, that is, whether the channel is busy or idle by performing an energy scan or detection on the channel.
  • Such a channel access mechanism may be referred to as Listen Before Talk (LBT) or Carrier Sense (CS).
  • LBT Listen Before Talk
  • CS Carrier Sense
  • the wireless communication device determines whether the channel is available for transmission based on the energy measured in the channel.
  • LBT may be performed frame-based or load-based.
  • parameters such as CCA, Extended CCA, channel occupancy time, idle period, CCA energy detection threshold may be defined.
  • a wireless communication device using an unlicensed band may perform (E) CCA at the end of an idle period before starting transmission on an operating channel. That is, the wireless communication device can grasp the occupancy state of the channel by performing (E) CCA for the (E) CCA execution time within the idle period. If the wireless communication device correctly receives the packet intended for the device on the channel occupied by the previous CCA, if it has not exceeded the maximum channel occupancy time, the wireless communication device does not perform (E) CCA again. (E.g., ACK and Block ACK frames) may be transmitted.
  • E.g., ACK and Block ACK frames may be transmitted.
  • the two nodes (LAA operator # 1 and the WLAN AP) perform LBTs at the same time.
  • the same channel may be obtained, and downlink transmission may be performed to the first terminal UE1 and the second terminal UE2 on the unlicensed band, respectively.
  • a wireless communication system e.g. LTE
  • transmits and receives a control / data information in a fixed format e.g. subframe / radio frame.
  • a fixed format e.g. subframe / radio frame.
  • a WLAN system such as WiFi
  • data transmission / reception may be performed by concatenating a band having a maximum size of 160 MHz.
  • wireless communication systems such as LTE systems define all physical layer operations based on fixed system bandwidth information.
  • the interval of the center carriers on the unlicensed band in the wireless communication system is 5 MHz, the overlapping is partially overlapped with each other due to inaccurate noise interference (NI) and inaccurate radio resource management (RRM). Resource occupancy may occur between different nodes, causing interference.
  • NI noise interference
  • RRM radio resource management
  • FIG. 6 illustrates a path loss estimation method according to an embodiment of the present invention.
  • a main serving cell (PCell) and two secondary serving cells (SCell # 1 and SCell # 2) are configured in a licensed band (L-band) and in an unlicensed band (U-band).
  • SCell # 3, SCell # 4, and SCell # 5 are configured in the case where three secondary serving cells (SCell # 3, SCell # 4, and SCell # 5) are configured.
  • SCell # 3, SCell # 4, and SCell # 5 are configured in the case where three secondary serving cells (SCell # 3, SCell # 4, and SCell # 5) are configured.
  • SCell # 3, SCell # 4, and SCell # 5 are configured.
  • a situation in which the DL CC of the secondary serving cell # 3 on the unlicensed band receives strong interference is illustrated.
  • the UE may perform the secondary serving in the DL CC of the secondary serving cell # 3 on the unlicensed band in which the path loss reference serving cell for the UL CC of the secondary serving cell # 3 on the unlicensed band is connected to SIB2 for a more reliable path loss estimation. It is possible to change to a DL CC of another secondary serving cell (SCell # 4 or SCell # 5) in an unlicensed band in an interference environment less than the DL CC of cell # 3. In this case, the terminal may perform more accurate power control for uplink transmission on the unlicensed band, thereby improving overall system performance.
  • the base station may transmit path-loss reference linking information for the secondary serving cell (s) configured on the unlicensed band to the terminal through RRC signaling.
  • the path loss reference connection information may be information on a secondary serving cell to be referred to when the path is lost among the secondary serving cells set on the unlicensed band, and may include an index of the secondary serving cell to be used for estimating the path loss.
  • the path loss reference connection information may be delivered by using a pathloss reference linking parameter included in an information element (IE) of an uplink power control dedicated SCell.
  • IE information element
  • the UE determines S-TAGs belonging to the S-TAG, except for a sub-serving cell corresponding to the uplink (SIB2-linkage) or a sub-serving cell corresponding to the uplink.
  • SIB2-linkage a sub-serving cell corresponding to the uplink
  • One of the secondary serving cells corresponding to the index of the secondary serving cell indicated by RRC signaling among other secondary serving cells in the TAG may be applied as a path loss reference serving cell.
  • a secondary serving cell carrying a PUCCH (that is, a secondary serving cell capable of PUCCH transmission) is configured in a secondary serving cell belonging to an S-TAG
  • One of the CCs may be configured as a path loss reference serving cell by RRC signaling. That is, when a DL CC of a specific secondary serving cell on an unlicensed band is subjected to strong interference, if a secondary serving cell carrying a PUCCH is configured in a secondary serving cell belonging to an S-TAG, the DL CC of the secondary serving cell carrying the PUCCH is It can be used to estimate the path loss of a DL CC in strong interference situations.
  • the path loss estimation value PL c estimated by the terminal with respect to the serving cell c may be calculated by Equation 1 below.
  • the 'referenceSignalPower' value is a value provided from the upper layer.
  • the upper layer filtering setting is based on the reference serving cell, and the RSRP (Reference Signal Received Power) value is measured based on the reference serving cell.
  • FIG. 7 is a flowchart illustrating the operation of a terminal according to an embodiment of the present invention.
  • the terminal may configure at least one secondary serving cell on the unlicensed band based on configuration information (hereinafter referred to as LAA configuration information) regarding the serving cell of the unlicensed band.
  • LAA configuration information may be transmitted from the base station to the terminal through the main serving cell of the licensed band, it may be transmitted through an RRC message.
  • the RRC message may be an RRC connection reconfiguration message.
  • the path loss is estimated at the time of uplink transmission (S720).
  • the path loss reference connection information may be information about a secondary serving cell to be referred to when a path is lost among secondary serving cells set on an unlicensed band, and may include an index of the secondary serving cell.
  • the secondary serving cell to be referred to when the path is lost may be a secondary serving cell different from the secondary serving cell used for the uplink transmission among the serving cells of the unlicensed band.
  • the UE may perform DL serving based on the path loss reference connection information for a DL CC to be referred for uplink transmission through the specific secondary serving cell.
  • the path loss of the specific secondary serving cell can be estimated by the DL CC of another secondary serving cell in the S-TAG to which the cell belongs.
  • the secondary serving cell carrying the PUCCH may be configured as a path loss reference serving cell by RRC signaling.
  • the UE may use the DL CC of the secondary serving cell carrying the PUCCH to estimate the path loss of the secondary secondary cell in a situation where the secondary secondary cell is subjected to strong interference.
  • FIG. 8 is a flowchart illustrating the operation of a base station according to an embodiment of the present invention.
  • the base station reports a status report, a sounding reference signal (SRS), and a PRACH from a terminal to a channel already set such as channel state information (CSI), reference signal received power (RSRP), and reference signal received quality (RSRQ).
  • An uplink signal such as a physical random access channel may be received.
  • the base station may estimate (inferred) the channel environment of the corresponding terminal based on the received signal (S810).
  • the RSRP value is defined as a value [W] that averages the power distribution of the REs transmitted by the CRS (or DRS) transmitted within the frequency bandwidth considered in the channel measurement.
  • the RSRQ value is defined as N ⁇ RSRP / (E-UTRA carrier RSSI), and the RSSI value represents an average value of all received powers in the measured frequency bandwidth.
  • the CSI considers the ratio of the power of the original signal to the power of the interference signal through downlink / uplink RSs (eg CRS, CSI-RS, SRS, etc.) and corresponding channel values (RI, PMI, CQI) corresponding thereto. This value is taken into account for scheduling.
  • the base station may determine whether to change the path loss reference serving cell of the terminal based on the estimated channel environment of the terminal (S820). To this end, the base station may, for example, estimate an interference situation of the corresponding UE based on the CSI value or determine the channel based on the RSRP / RSRQ value. For example, the base station may evaluate the quality of the original signal through the ratio of the RSRP / RSRQ value and other signals including power, interference and noise of the original signal.
  • CSI or path loss may be directly measured based on the SRS and PRACH signals.
  • the base station may evaluate and estimate a channel environment of the corresponding terminal by calculating a difference value between a predetermined SRS transmission power and the power of the SRS signal received by the base station.
  • the BLER (Block-Error Rate) value of the PUSCH (Physical Uplink Shared Channel) received from the UE is based on a target value (this is a preset value, it is applied as a parameter applied for base station / terminal implementation). It can be used, which is a value that can be adjusted in consideration of the service, which can be set by the service provider (network operator) in consideration of the network environment for the service). It can be determined that such a problem is caused by wrong power control, and the main cause is that wrong path loss estimation is performed at the terminal side.
  • the base station may change the reference serving cell for estimating the path loss performed by the terminal based on the path loss measured based on the SRS and PRACH signals. That is, the base station determines that the path loss estimation of the terminal is unreliable and can change the reference serving cell for the path loss estimation to another reference serving cell.
  • the base station compares the CSI, RSRP and RSRQ values reported from the terminal, the CSI measured by the base station directly based on the uplink SRS and PRACH, the path loss value, and the BLER of the PUSCH. These factors can be used to determine if the original signal is weak.
  • the base station is based on the channel information (CSI, RSRP, RSRQ) reported from the terminal and all or some bad value based on the value directly estimated by the base station uplink signal (SRS / PRACH) from the terminal If reported, the path loss reference serving cell may be changed.
  • the RRC signaling is triggered to change the path loss reference serving cell of the base station corresponding serving cell (S830), and the RRC indicating a change of the path loss reference serving cell for the corresponding serving cell.
  • the message is transmitted to the terminal (S840).
  • FIG 9 illustrates a path loss estimation method according to another embodiment of the present invention.
  • the path loss channel estimation method described with reference to FIGS. 6 to 8 may be usefully used in a situation where the channel environment has little change. However, in situations where the channel environment is changing (fast), there is a need to change the path loss reference serving cell more adaptively and dynamically.
  • LAA will consider how to effectively select multiple channels (carriers) on the unlicensed band to be set to S-TAG. That is, this means that a carrier is dynamically selected within a plurality of serving cells configured as a base station in one terminal view, and the selected secondary serving cell can be considered for the path loss estimation for the UL CC.
  • the path loss reference serving cell for the UL SCC on the unlicensed band set to S-TAG may be dynamically selected. That is, the path loss estimation for the set UL CC (UL CC of SCell # 3) may be dynamically changed based on the secondary serving cell of the (licensed) licensed band selected through (C) CCA after performing LBT.
  • the path loss is estimated even for the deactivated serving cell. If a specific serving cell occupies a channel after performing LBT at a specific time through physical layer signaling in the LAA, it may be changed to an "on” or “busy” state, otherwise it is an "off” or “Idle” state.
  • the serving cell of may also be in an "on” state.
  • the terminal In order to cope with such a possibility, the terminal always needs to prepare for uplink transmission by estimating a path loss even for a deactivated serving cell.
  • secondary serving cell # 3 (UL SCC # 3) (ie, path loss estimation for uplink transmission of secondary serving cell # 3).
  • UL SCC # 3 ie, path loss estimation for uplink transmission of secondary serving cell # 3.
  • the channel estimation for the UL SCC of the sub-serving cell # 3 is performed at the time t1. It may be performed based on the DL SCC of the secondary serving cell # 3 having the UL SCC of 3 and the SIB2 connection.
  • the DL SCC of the secondary serving cell # 4 in the "on" state is prepared to prepare for uplink transmission through the secondary serving cell # 3. Based on the channel estimation for the UL SCC of the secondary serving cell # 3 may be performed.
  • UL SCC # 3 when two serving cells SCell # 3 and SCell # 5 are in an “on” state as in time t3, there may be two choices in terms of UL SCC # 3. These are the secondary serving cell # 3 (DL SCC # 3) and the secondary serving cell # 5 having the UL SCC # 3 and the SIB2 connection. If a plurality of DL CCs are turned “on”, a path for one UL CC is performed. As a lost reference serving cell, a DL CC (ie, secondary serving cell # 3 in FIG. 9) having an SIB2 connection with a corresponding UL CC (UL SCC # 3) may be selected with the highest priority.
  • DL SCC # 4 and DL SCC # 5 are "on" at time t3
  • DL SCC # 4 may be selected as a path loss reference serving cell for UL SCC # 3.
  • a serving cell configured for RRC signaling has a higher priority. Can have.
  • information about the priority for all serving cells in the S-TAG may be indicated by RRC signaling.
  • a specific serving cell c belongs to a TAG that does not include the primary serving cell and a channel is obtained through (E) CCA on the serving cell c
  • the terminal always refers to the serving cell c for path loss estimation. Can be used as a serving cell.
  • the serving cell c belongs to a TAG that does not include the main serving cell and the channel is not obtained through (E) CCA on the serving cell c and the channel is obtained on another serving cell in the same TAG, the terminal A serving cell obtained with a channel can always be used as a path loss reference serving cell.
  • a serving cell having the smallest secondary serving cell index may be used as a path loss reference serving cell. This is because the last distinguishable element is the serving cell index (sub-serving cell index) if the channel state of the plurality of serving cells in which the channel is obtained is the same state.
  • the serving cell selected based on the priority indicated by the RRC signaling may be used as the path loss reference serving cell.
  • FIG. 10 is a flowchart illustrating the operation of a terminal according to another embodiment of the present invention.
  • the terminal sets at least one secondary serving cell on the unlicensed band to S-TAG and is set to S-TAG.
  • the path loss reference serving cell for the UL SCC on the band may be dynamically selected (S1010).
  • the path loss of the secondary serving cell in the unlicensed band may be estimated based on the selected path loss reference serving cell (S1020).
  • the UE may preferentially use a serving cell including a DL CC connected to SIB2 to the specific secondary serving cell as a reference serving cell for path loss estimation.
  • the terminal may use the other secondary serving cell as a path loss reference serving cell. If there are a plurality of secondary serving cells from which the channel is obtained, the secondary serving cell having the smallest secondary serving cell index is used as the path loss reference serving cell or the path loss reference serving cell is selected based on the priority indicated by RRC signaling. Can be.
  • FIG. 11 is a block diagram illustrating a wireless communication system according to an embodiment of the present invention.
  • a wireless communication system supporting LAA includes at least one terminal 1100 and at least one base station 1200.
  • Each terminal 1100 includes an RF unit 1110, a processor 1120, and a memory 1130.
  • the memory 1130 is connected to the processor 1120 and stores various information for driving the processor 1120.
  • the RF unit 1110 is connected to the processor 1120 to transmit and / or receive a radio signal.
  • the RF unit 1110 may receive an RRC message from the base station 1200 and transmit an uplink signal such as CSI, RSRP, RSRQ, SRS, and PRACH to the base station 1200.
  • the memory 1130 may store LAA configuration information, information about a path loss reference serving cell, and the like, and provide the information to the processor 1120 according to a request of the processor 1120.
  • the processor 1120 implements the functions, processes, and / or methods proposed herein. Specifically, the processor 1120 allows the steps according to FIGS. 3 and / or 10 to be performed.
  • the processor 1120 may include a setting unit 1121 and an estimating unit 1122.
  • the setting unit 1121 sets a path loss reference serving cell for the secondary serving cell configured in the unlicensed band based on the information on the path loss reference serving cell included in the RRC message. For example, the setting unit 1121 may determine a path loss of a secondary serving cell set in the unlicensed band based on path loss reference connection information included in an information element of an uplink power control dedicated SCell in the RRC message. The index of the reference serving cell can be checked.
  • the estimator 1122 estimates a path loss during uplink transmission through the secondary serving cell set in the unlicensed band using the path loss reference serving cell. For this purpose, the estimator 1122 may use Equation 1 below.
  • the setting unit 1121 uses the path loss reference serving cell included in the RRC message to estimate the path loss of the secondary serving cell configured on the unlicensed band.
  • the path loss reference serving cell may be a secondary serving cell to be referred to when a path is lost among secondary serving cells configured on an unlicensed band.
  • the RRC message may include an index of the path loss reference serving cell.
  • the setting unit 1121 may determine a DL CC to be referred for uplink transmission through the specific secondary serving cell as the path loss reference connection information. Based on the sub serving cell may be set to the DL CC of the other secondary serving cell in the S-TAG. However, if the secondary serving cell carrying the PUCCH is configured in the secondary serving cell belonging to the S-TAG, the setting unit 1121 may set the secondary serving cell carrying the PUCCH as a path loss reference serving cell.
  • the information on the secondary serving cell for the PUCCH may be transmitted to the terminal through the RRC signaling, the estimator 1122 is a secondary serving cell carrying the PUCCH in a situation that a particular secondary serving cell is subjected to strong interference.
  • DL CC may be used to estimate a path loss of the specific secondary serving cell.
  • the setting unit 1121 dynamically selects a path loss reference serving cell for the UL SCC on the unlicensed band set to S-TAG, depending on whether the channel is obtained through (e) CCA of the unlicensed band and thus the path loss. It can be set as a reference serving cell.
  • the estimator 1122 may dynamically perform path loss estimation for uplink transmission through the unlicensed band based on the secondary serving cell of the unlicensed band set as the path loss reference serving cell. For example, the estimator 1122 always loses the path of the particular serving cell if the particular serving cell belongs to a TAG that does not include the primary serving cell and the channel is obtained through (E) CCA on the specific serving cell.
  • the estimator 1122 may always use a serving cell from which a channel is obtained as a path loss reference serving cell. In this case, if there are a plurality of serving cells in which channels are acquired, the serving cell having the smallest secondary serving cell index is used as the path loss reference serving cell, or the path loss is selected based on the priority indicated by the RRC signaling. Can be used as a reference serving cell.
  • the base station 1200 includes a radio frequency unit 1210, a processor 1220, and a memory 1230.
  • the memory 1230 is connected to the processor 1220 and stores various information for driving the processor 1220.
  • the RF unit 1210 is connected to the processor 1220 and transmits and / or receives a radio signal.
  • the processor 1220 implements the functions, processes, and / or methods proposed herein. In the above-described embodiment, the operation of the base station 1200 may be implemented by the processor 1220.
  • the processor 1220 generates an RRC message published herein and performs an (E) CCA for an unlicensed band to obtain a channel.
  • the processor 1220 may include a determiner 1221 and a generator 1222.
  • the determination unit 1221 determines a channel environment of the terminal 1100 based on a status report on a predetermined channel such as CSI, RSRP, RSRQ, etc. received from the terminal 1100, and determines an uplink signal such as SRS and PRACH. Based on this, the channel environment of the terminal 1100 may be directly estimated. Then, it may be determined whether to change the path loss reference serving cell of the terminal based on the estimated channel environment of the terminal.
  • the determination unit 1221 indicates that the UE has sent an incorrect path loss estimation value. You can judge.
  • the generation unit 1222 may generate an RRC message indicating change of the reference serving cell for the path loss estimation performed by the terminal 1100.
  • the determination unit 1221 compares the value directly estimated based on the channel information (CSI, RSRP, RSRQ) reported from the terminal 1100 and the uplink signal (SRS / PRACH) from the terminal 1100. Does not reach a certain threshold from the terminal (1100) The path loss reference serving cell may be changed only for the serving cell whose value is reported.
  • CSI channel information
  • RSRP RSRP
  • RSRQ uplink signal
  • the above-described processor may include an application-specific integrated circuit (ASIC), another chipset, a logic circuit and / or a data processing device.
  • the memory may include read-only memory (ROM), random access memory (RAM), flash memory, memory card, storage medium and / or other storage device.
  • the RF unit may include a baseband circuit for processing a radio signal.
  • the above-described technique may be implemented as a module (process, function, etc.) for performing the above-described function.
  • the module may be stored in memory and executed by a processor.
  • the memory may be internal or external to the processor and may be coupled to the processor by various well known means.

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Abstract

L'invention concerne un procédé et un dispositif destinés à l'estimation de l'affaiblissement de propagation dans un système de communication sans fil prenant en charge un LAA. Le procédé d'estimation de l'affaiblissement de propagation dans un système de communication sans fil comprend : la réception par un terminal d'un message de commande de ressource radio (RRC) en provenance d'une station de base, une agrégation de porteuses entre une cellule de desserte d'une bande sous licence et une cellule de desserte d'une bande sans licence étant configurée pour ce terminal; et l'estimation de l'affaiblissement de propagation au moment de la transmission de liaison montante par l'intermédiaire d'une cellule de desserte secondaire configurée dans la bande sans licence, sur la base d'informations relatives à une cellule de desserte de référence d'affaiblissement de propagation incluse dans le message RRC.
PCT/KR2015/013598 2015-01-30 2015-12-11 Procédé et dispositif destinés à l'estimation de l'affaiblissement de propagation dans un système de communication sans fil prenant en charge un laa Ceased WO2016122112A1 (fr)

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CN112088550A (zh) * 2018-05-11 2020-12-15 联想（新加坡）私人有限公司 基于路径损耗估计发送上行链路传输的方法和装置
CN112088550B (zh) * 2018-05-11 2024-04-26 联想（新加坡）私人有限公司 基于路径损耗估计发送上行链路传输的方法和装置

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