WO2016119325A1

WO2016119325A1 - Csi measurement and feedback method, csi measurement and feedback system, and base station

Info

Publication number: WO2016119325A1
Application number: PCT/CN2015/077995
Authority: WO
Inventors: 李明菊; 朱亚军; 张云飞
Original assignee: 宇龙计算机通信科技(深圳)有限公司
Priority date: 2015-01-30
Filing date: 2015-04-30
Publication date: 2016-08-04
Also published as: CN104579518A; CN104579518B

Abstract

The present invention provides a CSI measurement and feedback method and system, and a base station when an LTE system works in an unlicensed spectrum. The method comprises: when a downlink service arrives, detecting a current downlink channel state, and sending CSI measurement configuration signaling and CSI feedback configuration signaling that correspond to the current downlink channel state to a terminal according to the current downlink channel state; or when a downlink service arrives, sending CSI measurement configuration signaling and CSI feedback configuration signaling that correspond to a specified downlink channel state to a terminal, so that after the terminal learns the downlink channel state, the terminal performs CSI measurement and a CSI feedback according to the CSI measurement configuration signaling and the CSI feedback configuration signaling that correspond to the downlink channel state. By means of the technical solutions of the present invention, it can be effectively ensured that CSI measurement and a CSI feedback can be normally performed after an LTE system introduces an LBT mechanism to an unlicensed spectrum.

Description

CSI measurement and feedback method, CSI measurement and feedback system and base station

This application claims priority to Chinese Patent Application No. CN 201510052163.9, entitled "CSI Measurement and Feedback Method, CSI Measurement and Feedback System and Base Station" on January 30, 2015, all contents of which are filed on January 30, 2015. This is incorporated herein by reference.

Technical field

The present invention relates to the field of communications technologies, and in particular, to a channel detection method when an LTE system operates in an unlicensed frequency band, a channel detection system when the LTE system operates in an unlicensed frequency band, and a base station.

Background technique

With the dramatic increase in communication traffic, 3GPP licensed spectrum is increasingly insufficient to provide higher network capacity. To further increase the utilization of spectrum resources, 3GPP is discussing how to use unlicensed spectrum, such as the 2.4 GHz and 5 GHz bands, with the help of licensed spectrum. These unlicensed spectrum are currently mainly used in systems such as Wi-Fi, Bluetooth, radar, and medical.

In general, access technologies designed for licensed bands, such as LTE (Long Term Evolution), are not suitable for use in unlicensed bands, because access technologies such as LTE are very demanding for spectrum efficiency and user experience optimization. high. However, the Carrier Aggregation (CA) feature makes it possible to deploy LTE in unlicensed bands. 3GPP proposes the concept of LAA (Licensed Assisted Access), which uses the help of LTE licensed spectrum to use unlicensed spectrum. The unlicensed spectrum can work in two modes. One is the downlink (SDL), that is, only the downlink transmission subframe, and the other is the TDD (Time Division duplex) mode, which includes the downlink transmission. The subframe also includes an uplink transmission subframe. This situation can only be supplemented by the carrier aggregation technology (as shown in Figure 1). The TDD mode can be used independently of DC (Dual Connectivity).

Compared with Wi-Fi systems, LTE systems operating in unlicensed bands have the ability to provide higher spectral efficiency and greater coverage, while allowing data traffic to be in licensed bands and unlicensed based on the same core network. Seamless switching between right bands. For the user, this means a better broadband experience, higher speed, better stability and mobility.

Existing access technologies used on unlicensed spectrum, such as Wi-Fi, have weaker anti-jamming capabilities. In order to avoid interference, the Wi-Fi system has designed many interference avoidance rules, such as CSMA/CD (Carrier Sense Multiple Access/Collision Detection). The basic principle of this method is Wi-Fi. Before the AP (Access Point) or the terminal sends signaling or data, it must first monitor whether other APs or other terminals are transmitting/receiving signaling or data. If so, continue to listen until it is monitored. If not, a random number is generated as the backoff time. If no signaling or data transmission is detected during this backoff time, the AP or the terminal may start transmitting signaling or data after the end of the backoff time. The process is shown in Figure 2.

However, since the LTE network has good orthogonality to ensure the interference level, the uplink and downlink transmissions between the base station and the user do not need to consider whether other base stations or other users are transmitting data. If LTE is used on an unlicensed band, it does not consider whether other devices are using unlicensed bands nearby, which will cause great interference to Wi-Fi devices. Because LTE transmits as long as there is traffic, there is no monitoring rule, then the Wi-Fi device cannot transmit when LTE has service transmission, and can only detect the channel idle state for data transmission after the LTE service transmission is completed.

Therefore, one of the most important key points when using an unlicensed band in an LTE network is to ensure that the LAA can coexist with existing access technologies (such as Wi-Fi) on a fair and friendly basis. In the traditional LTE system, there is no LBT (Listen Before Talk) mechanism to avoid collisions. In order to coexist better with Wi-Fi systems, LTE introduces an LBT mechanism.

As shown in FIG. 3, the LBT detection repetition period is 10 ms, and the LBT detection subframe is 1 ms. In the first cycle of Figure 3, the LBT detection channel is idle, indicating that the surrounding interference is small, and other subframes in this period can be occupied. The LBT detection channel in the second cycle is busy, indicating that the surrounding interference is very large, and other subframes in this period cannot be occupied.

In this case, how to measure and feedback the channel state information (CSI) used by the user for downlink scheduling is a problem to be considered. The CSI information includes a CQI (Channel Quality Indicator), an RI (Rank Indicator), and a PMI (Precoding Matrix Indicator). The main questions include the following: (1) When to start testing Volume CSI? (2) When the channel state detection is busy, is it necessary to measure CSI, whether feedback is needed, and based on what signal is measured, what is the measurement period and feedback period? (3) When the channel state is detected as idle, is it necessary to measure CSI, whether feedback is needed, and based on what signal is measured, what is the measurement period and feedback period? (4) Does the CSI information need to be updated at the base station?

Therefore, how to ensure the normal implementation of CSI measurement and CSI feedback after the LTE system introduces the LBT mechanism in the unlicensed frequency band becomes a technical problem to be solved.

Summary of the invention

The present invention is based on the above problems, and proposes a new technical solution, which can ensure the normal implementation of CSI measurement and CSI feedback after the introduction of the LBT mechanism in the unlicensed frequency band of the LTE system, and ensure that when the latest CSI information has not been obtained yet. The CSI information can be obtained, so that the base station can select a more suitable modulation and coding mode, and further improve the spectrum efficiency and channel usage.

In view of this, an aspect of the present invention provides a CSI measurement and feedback method for an LTE system when operating in an unlicensed frequency band, and is used by the base station side, including: when a downlink service arrives, detecting a current downlink channel state, and according to Transmitting, by the current downlink channel state, CSI measurement configuration signaling and CSI feedback configuration signaling corresponding to the current downlink channel state to the terminal; or transmitting CSI measurement corresponding to the specified downlink channel state to the terminal when a downlink service arrives The signaling and the CSI feedback configuration signaling are configured to enable the terminal to perform CSI measurement and CSI feedback according to CSI measurement configuration signaling and CSI feedback configuration signaling corresponding to the downlink channel state after learning the downlink channel state.

In the technical solution, when a downlink service arrives and the downlink channel state is known, the CSI measurement and the CSI feedback configuration signaling corresponding to the current downlink channel state are sent to the terminal, or when the downlink channel state is unknown, Transmitting CSI measurement and CSI feedback configuration signaling corresponding to the specified downlink channel state to the terminal, so that the terminal performs CSI measurement and CSI detection according to the corresponding CSI measurement and CSI feedback configuration signaling after learning the downlink channel state, so that The CSI measurement and the CSI feedback are normally performed after the LBT mechanism is introduced in the unlicensed frequency band to ensure the spectrum efficiency and the channel usage rate. The specified downlink channel state includes the downlink channel busy state or the downlink channel idle state.

In the above technical solution, preferably, the sending corresponds to the current downlink channel state. Before the CSI measurement configuration signaling and the CSI feedback configuration signaling or the CSI measurement configuration signaling and the CSI feedback configuration signaling corresponding to the specified downlink channel state, the method further includes: setting CSI corresponding to the downlink channel busy state and the downlink channel idle state, respectively. Measurement configuration signaling and CSI feedback configuration signaling.

In the above technical solution, preferably, the configuration content of the CSI measurement configuration signaling and the CSI feedback configuration signaling corresponding to the downlink channel busy state specifically includes: a first signal indicating that the terminal is used for CSI measurement, and the first CSI measurement time and frequency position, first CSI measurement period, first CSI feedback time, and first CSI feedback period; and configuration content of CSI measurement configuration signaling and CSI feedback configuration signaling corresponding to the downlink channel idle state The method includes: a second signal indicating the CSI measurement by the terminal, a second CSI measurement time and frequency position, a second CSI measurement period, a second CSI feedback time, and a second CSI feedback period.

In the technical solution, CSI measurement configuration signaling and CSI feedback configuration signaling corresponding to the downlink channel state (downlink channel busy and downlink channel idle), and CSI measurement configuration signaling and CSI corresponding to the downlink channel busy state are set. The configuration content of the feedback configuration signaling includes, but is not limited to, a first signal indicating the CSI measurement by the terminal (a signal for CSI measurement), a first CSI measurement time and a frequency position, a first CSI measurement period, and a first The CSI measurement configuration time and the first CSI feedback period, the configuration content of the CSI measurement configuration signaling and the CSI feedback configuration signaling corresponding to the downlink channel idle state includes, but is not limited to: a second signal indicating that the terminal is used for CSI measurement (using The CSI measured time and frequency position, the second CSI measurement period, the second CSI feedback time, and the second CSI feedback period are corresponding to the CSI measurement and feedback signaling by configuring the downlink channel state and configuring Corresponding main content, to clearly indicate whether the CSI needs to be measured and fed back when the downlink channel state is different, and based on which information is used for CSI measurement and Feed, thereby effectively ensure that the introduction of the LTE system in the LBT mechanism unlicensed band CSI feedback CSI measurement and normal.

In the above technical solution, preferably, the first signal indicating that the terminal is used for CSI measurement comprises one or a combination of the following: a PSS/SSS signal transmitted in a first cycle, and a CRS signal transmitted in a second cycle. a CSI-RS signal transmitted in a third period and a DRS signal transmitted in a fourth period; the first CSI measurement time and frequency position being a first transmission time of the signal indicating that the terminal is used for CSI measurement a frequency position; the first CSI measurement period is greater than or equal to a maximum of the first period, the second period, the third period, and the fourth period One cycle of the first CSI feedback period is greater than or equal to the first CSI measurement period; and the second signal indicating that the terminal is used for CSI measurement includes one or a combination of the following: sending according to the fifth cycle PSS/SSS signal, CRS signal transmitted in the sixth cycle, CSI-RS signal transmitted in the seventh cycle, and DRS signal transmitted in the eighth cycle; the second CSI measurement time and frequency position is the second The CSI measurement configuration signaling provides a subframe number and a subcarrier position indicating that the terminal is used for CSI measurement; and the second CSI measurement period is greater than or equal to the fifth period, the sixth period, and the seventh period And a second one of the eighth periods; the second CSI feedback period is greater than or equal to the second CSI measurement period, wherein the fifth period is less than or equal to the first period, the sixth The period is less than or equal to the second period, the seventh period is less than or equal to the third period, the eighth period is less than or equal to the fourth period, and the second CSI measurement period is less than or equal to First CSI Measurement Week And the second CSI feedback period is less than or equal to the first CSI feedback period, and the first CSI feedback time and the second CSI feedback time include: feedback when detecting an uplink channel idle, or at the CSI Direct feedback after the measurement is over.

In the above technical solution, preferably, the configuration content of the CSI measurement configuration signaling and the CSI feedback configuration signaling corresponding to the downlink channel busy state and the downlink channel idle state specifically includes: performing the CSI measurement aperiodically. And the CSI feedback.

In this technical solution, the signal indicating the CSI measurement by the first indication terminal corresponding to the downlink channel busy state includes but is not limited to one or a combination of the following: PSS/SSS (Primary Synchronization) transmitted in the first cycle (large cycle) Signal, Secondary Synchronization Signal (Secondary Synchronization Signal) signal, CRS (Common Reference Signal) signal transmitted in the second period (large period), CSI transmitted in the third period (large period) An RS (Channel State Information-Reference Signal) signal and a DRS (Discovery Reference Signal) signal transmitted in a fourth period (large period), and a second indication corresponding to a downlink channel idle state The signal used by the terminal for CSI measurement includes but is not limited to one or a combination of the following: a PSS/SSS signal transmitted in a fifth cycle (small cycle), a CRS signal transmitted in a sixth cycle (small cycle), and a seventh cycle. a (small period) CSI-RS signal transmitted and a DRS signal transmitted in an eighth period (small period), wherein the first period, the second period, and the third week And fourth endless cycle All the same, the fifth period, the sixth period, the seventh period, and the eighth period are not completely the same, and the fifth period, the sixth period, the seventh period, and the eighth period are respectively less than or equal to the first period and the second period, respectively. The period, the third period, and the fourth period, that is, the terminal can be notified to perform CSI measurement and CSI feedback in multiple manners; and the start time of the CSI measurement and feedback corresponding to the downlink channel busy state and the downlink channel idle state (first CSI measurement time) And the frequency position and the second CSI measurement time and frequency position) are respectively a transmission time indicating a signal used by the terminal for CSI measurement and a subframe number and a subcarrier position for CSI measurement given in the signaling; and the downlink channel is busy or The CSI feedback period corresponding to the downlink idle state is greater than the CSI measurement period, and the CSI measurement period is greater than or equal to the largest one of the first period, the second period, the third period, and the fourth period, and the fifth period and the sixth period, respectively. The largest one of the seventh and eighth periods; and CS can be detected when the uplink channel is idle or the channel status is uncertain. I feedback, that is, the CSI feedback time can be arbitrarily set; of course, CSI measurement and CSI feedback can also be performed non-periodically. When the downlink channel state is known or unknown, CSI measurement and feedback can be performed based on which signals are explicitly determined. And clarify the time and period of CSI measurement and feedback, thereby effectively ensuring the normal operation of CSI measurement and CSI feedback after the LTE system introduces the LBT mechanism in the unlicensed band.

In the foregoing technical solution, preferably, CSI measurement configuration signaling, CSI feedback configuration signaling, and CSI feedback corresponding to the downlink channel busy state and the downlink channel idle state are sent on the unlicensed band or the licensed band. information.

In this technical solution, CSI measurement configuration signaling and CSI feedback configuration signaling corresponding to different downlink channel states, and CSI information that needs feedback after the terminal performs CSI measurement may be sent on an unlicensed band or a licensed band, to Improve spectrum efficiency and channel utilization.

In the above technical solution, preferably, when the channel detection is repeatedly performed on the unlicensed frequency band in a fixed period, the downlink channel busy state or the CSI measurement configuration signaling and CSI feedback configuration signaling of a downlink channel idle state; or when receiving the downlink service, performing downlink channel detection on the unlicensed frequency band and detecting that the downlink channel is idle, according to Determining, by the RRC signaling, the MAC signaling, and/or the DCI signaling, the CSI measurement time and the frequency location are determined by the RRC signaling, the MAC signaling, and/or the DCI signaling manner, and the downlink channel is idle. State CSI measurement configuration signaling and CSI feedback configuration signaling.

In this technical solution, when downlink channel detection (based on FBE (Framed based equipment) LBT mechanism) is repeated in a fixed period on an unlicensed frequency band, that is, channel detection time is periodically repeated, and CSI measurement is performed at this time. The time and frequency position, such as the subframe number, are relatively easy to indicate to the terminal, that is, the direct RRC (Radio Resource Connection) signaling can be indicated once, and then the channel can be freely checked every time. The subframe number indicated by the RRC signaling is measured and fed back; or when downlink traffic arrives and downlink channel detection is performed on the unlicensed frequency band (LBT mechanism based on LBE (Load Based Equipment)), that is, channel detection time Non-periodic occurrence, and there is no channel busy time in this case, because if the channel is busy, channel detection is always performed, then only channel detection time and channel idle time, if the channel is detected to be idle, then the base station can only After each time the channel is detected to be idle, a CSI measurement is set according to the start time and the end time of the channel idle. Time and frequency location, and then, through RRC signaling, MAC (Medium access control) signaling or DCI (Downlink control indicator) signaling, the terminal CSI is informed of the time and frequency position; thus, it can be ensured How to inform the terminal of the CSI measurement time and frequency position under different LBT mechanisms and different channel states, so as to ensure the normal operation of CSI measurement and CSI feedback after the LTE system introduces the LBT mechanism in the unlicensed frequency band.

In the above technical solution, preferably, the adjacent subframe after the channel detection time transmits CSI measurement configuration signaling and CSI feedback configuration signaling corresponding to the downlink channel busy state; or when the downlink channel is detected to be idle. Transmitting, by the terminal, a channel idle indication, so that after receiving the channel idle indication, the terminal performs, according to the received CSI measurement configuration signaling and CSI feedback configuration signaling corresponding to the downlink channel idle state. CSI measurements and the CSI feedback.

In this technical solution, when CSI is measured regardless of whether the downlink channel is busy or not, the base station may transmit a signal for measuring CSI in a neighboring subframe after the channel detection time, and the terminal may be adjacent to the subframe after the channel detection time. The frame measures CSI and performs feedback (this method is applicable to the FBE-based LBT mechanism); or, when the base station performs downlink channel detection and detects that the downlink channel is idle, it immediately sends a channel idle indication to enable the terminal to receive the channel. After the idle indication, the CSI measurement is performed immediately. At this time, the base station can perform CSI after the terminal receives the channel idle indication. After the time required for the measurement, the signal for the CSI measurement is transmitted, that is, after the terminal just receives the channel idle indication, the signal for performing the CSI measurement can also be transmitted (this method is applicable to the LBT mechanism based on FBE and LBE). In this way, it is possible to transmit a signal indicating that the terminal is used for CSI measurement in a suitable subframe, so as to effectively reduce the delay in the period after the base station detects the channel idle and the terminal measures and feeds back the CSI, so that the terminal can be as early as possible. The CSI is measured and fed back to improve spectral efficiency and channel utilization.

In the above technical solution, preferably, before the receiving the CSI feedback, the stored CSI information of the adjacent time fed back by the terminal is used as the current CSI information, or the lowest modulation coding mode is adopted, or RRM measurement result of the cell to which the base station belongs, RRM measurement result of other cells adjacent to the cell, and current CSI information determined by channel busy or switch state of the neighboring other cell; and the use of the stored The CSI information of the adjacent time fed back by the terminal as the current CSI information specifically includes: when the CSI information of the adjacent time is the CSI information of the busy state of the channel, according to the CSI information of the adjacent time, and the adjacent time The RSSI information at the time of channel detection corresponding to the CSI information and the RSSI information at the time of the current channel detection determine the current CSI information; or when the CSI information of the adjacent time is the CSI information of the downlink channel busy state, according to the The current CSI information is determined by the RSRP information of the cell to which the base station belongs and the RSSI information when the channel is currently detected.

In this technical solution, before receiving the CSI that is newly measured and fed back by the terminal, the base station may obtain current CSI information (alternative CSI information) by using the following methods, including: using the neighboring time feedback of the terminal stored by the base station. CSI information (the most recent CSI information), or the RRM (Radio Resource Management) measurement result of the cell to which the base station belongs, the RRM measurement result of other cells adjacent to the cell, and the channel of the adjacent other cell The busy or switch state determines the current CSI information, such as the current CSI information = the current cell (the cell to which the base station belongs), the RSRP (Reference Signal receiving power) / (the current cell RSRP + the surrounding strong cell in the open state) RSRP); in this way, the base station can even choose a more suitable modulation and coding mode, or use the lowest modulation coding mode.

The CSI information of the adjacent time fed back by the terminal stored by the base station as the current CSI information specifically includes: if the latest interval time is short, and the downlink channel idle state is also CSI information; if the latest one is separated by a short time and is the CSI information of the downlink channel busy state, the adjacent CSI information (old CSI information) and the RSSI corresponding to the channel detection (Received signal strength) Indication, received signal strength indication) information, combined with RSSI information (new RSSI information) at the time of current channel detection, to determine current CSI information, such as current CSI information = (new RSSI / old RSSI) * old CSI, or The current CSI information is determined by using the RSRP information of the cell to which the base station belongs and the RSSI information of the current channel detection, such as the current CSI information=the RSRP/new RSSI of the cell to which the base station belongs.

According to another aspect of the present invention, a CSI measurement and feedback system for an LTE system operating in an unlicensed frequency band is provided for a base station side, including: a control unit, configured to control and detect a current downlink channel when a downlink service arrives a state, and controlling to send CSI measurement configuration signaling and CSI feedback configuration signaling corresponding to the current downlink channel state to the terminal according to the current downlink channel state, or for transmitting, when a downlink service arrives, controlling to send to the terminal Determining the CSI measurement configuration signaling and the CSI feedback configuration signaling of the downlink channel state, so that the terminal performs CSI according to the CSI measurement configuration signaling and the CSI feedback configuration signaling corresponding to the downlink channel state after learning the downlink channel state. Measurement and CSI feedback.

In the above technical solution, preferably, the method further includes: a setting unit, configured to send CSI measurement configuration signaling and CSI feedback configuration signaling corresponding to the current downlink channel state or a CSI measurement configuration corresponding to the specified downlink channel state. Before signaling and CSI feedback configuration signaling, CSI measurement configuration signaling and CSI feedback configuration signaling respectively corresponding to the downlink channel busy state and the downlink channel idle state are set.

In the above technical solution, preferably, the setting unit is specifically configured to: set corresponding to the The configuration content of the CSI measurement configuration signaling and the CSI feedback configuration signaling of the downlink channel busy state specifically includes: a first signal indicating the CSI measurement by the terminal, a first CSI measurement time and frequency position, and a first CSI measurement period. The first CSI feedback time and the first CSI feedback period; and the configuration content of the CSI measurement configuration signaling and the CSI feedback configuration signaling corresponding to the downlink channel idle state specifically includes: the second indication that the terminal is used for CSI The measured signal, the second CSI measurement time and frequency position, the second CSI measurement period, the second CSI feedback time, and the second CSI feedback period.

In the above technical solution, preferably, the setting unit is further configured to: set the first signal indicating that the terminal is used for CSI measurement, including one or a combination of the following: PSS/SSS sent in a first cycle a signal, a CRS signal transmitted in a second period, a CSI-RS signal transmitted in a third period, and a DRS signal transmitted in a fourth period; setting the first CSI measurement time and frequency position as the first indication a transmission time and a frequency position of the signal used by the terminal for CSI measurement; setting the first CSI measurement period to be greater than or equal to a maximum of the first period, the second period, the third period, and the fourth period One cycle of setting the first CSI feedback period is greater than or equal to the first CSI measurement period; and setting the second signal indicating that the terminal is used for CSI measurement includes one or a combination of the following: Periodically sent a PSS/SSS signal, a CRS signal transmitted in a sixth cycle, a CSI-RS signal transmitted in a seventh cycle, and a DRS signal transmitted in an eighth cycle; setting the second CSI measurement time and frequency position as the second a CSI measurement configuration signaling, indicating a subframe number and a subcarrier position of the terminal for CSI measurement; setting the second CSI measurement period to be greater than or equal to the fifth period, the sixth period, and the seventh a period and a maximum one of the eighth periods; setting the second CSI feedback period to be greater than or equal to the second CSI measurement period, wherein the fifth period is less than or equal to the first period, The sixth period is less than or equal to the second period, the seventh period is less than or equal to the third period, the eighth period is less than or equal to the fourth period, and the second CSI measurement period is less than or equal to The first CSI measurement period, the second CSI feedback period is less than or equal to the first CSI feedback period, and setting the first CSI feedback time and the second CSI feedback time includes: when detecting an uplink channel idle Feedback Or directly feedback after the CSI measurement is over.

In the above technical solution, preferably, the setting unit is further configured to: set configuration content of CSI measurement configuration signaling and CSI feedback configuration signaling corresponding to the downlink channel busy state and the downlink channel idle state. The method includes: performing the CSI measurement and the CSI feedback aperiodically.

In this technical solution, the signal indicating the CSI measurement by the first indication terminal corresponding to the busy state of the channel includes but is not limited to one or a combination of the following: the PSS transmitted in the first period (large period) is sent in the first period. PSS/SSS (Primary Synchronization Signal, Secondary Synchronization Signal) signal, CRS (Common Reference Signal) signal transmitted in the second period (large period), according to the third period (large Periodically transmitted CSI-RS (Channel State Information-Reference Signal) signal and DRS (Discovery Reference Signal) signal transmitted in the fourth period (large period), and idle with the downlink channel The second indication terminal corresponding to the state for the CSI measurement includes, but is not limited to, one of the following or a combination thereof: the PSS/SSS signal transmitted in the fifth period (small period), and the CRS transmitted in the sixth period (small period) a signal, a CSI-RS signal transmitted in a seventh cycle (small cycle), and a DRS signal transmitted in an eighth cycle (small cycle), wherein the first cycle, the first Period, the third period and the fourth period are not identical, the fifth cycle, the sixth cycle, seventh and eighth periodic cycles are not identical, and the fifth The period, the sixth period, the seventh period, and the eighth period are respectively less than or equal to the first period, the second period, the third period, and the fourth period, that is, the terminal can be notified to perform CSI measurement and CSI feedback in multiple manners; The start time of the CSI measurement and feedback corresponding to the downlink channel busy state and the downlink channel idle state (the first CSI measurement time and frequency position and the second CSI measurement time and frequency position) are respectively sent to indicate the signal used by the terminal for CSI measurement. The subframe number and the subcarrier position for the CSI measurement given in the time and signaling; the CSI feedback period corresponding to the downlink channel busy or downlink idle state is greater than the CSI measurement period, and the CSI measurement period is greater than or equal to the first period, a maximum one of the second period, the third period, and the fourth period and a maximum one of the fifth period, the sixth period, the seventh period, and the eighth period; and may detect an uplink channel idle or channel If the state is uncertain, CSI feedback is performed, that is, the CSI feedback time can be arbitrarily set; of course, the CSI measurement can also be performed non-periodically. And CSI feedback, when the channel status is known or unknown, the CSI measurement and feedback can be performed based on which signals are explicitly determined, and the time and period of CSI measurement and feedback are clarified, thereby effectively ensuring that the LTE system is on the unlicensed band. The CSI measurement and CSI feedback are performed normally after the introduction of the LBT mechanism.

In the foregoing technical solution, the control unit is specifically configured to: control, in the unlicensed frequency band or the licensed frequency band, to send CSI measurement configuration signaling corresponding to the downlink channel busy state and the downlink channel idle state. And CSI feedback configuration signaling and CSI feedback information.

In the above technical solution, the control unit is further configured to: when the channel detection is repeatedly performed in a fixed period on the unlicensed frequency band, control is directly sent to the terminal by means of RRC signaling. And performing CSI measurement configuration signaling and CSI feedback configuration signaling in the downlink channel busy state or the downlink channel idle state; or when receiving the downlink service, performing downlink channel detection on the unlicensed frequency band and When detecting that the downlink channel is idle, the control determines the CSI measurement time and the frequency position according to the start time and the end time of the downlink channel idle, and performs the manner by using RRC signaling, MAC signaling, or DCI signaling. The terminal transmits CSI measurement configuration signaling and CSI feedback configuration signaling corresponding to the downlink channel idle state.

In this technical solution, when downlink channel detection (based on FBE (Framed based equipment) LBT mechanism) is repeated in a fixed period on an unlicensed frequency band, that is, channel detection time is periodically repeated, and CSI measurement is performed at this time. The time and frequency position, such as the subframe number, are relatively easy to indicate to the terminal, that is, the direct RRC (Radio Resource Connection) signaling can be indicated once, and then the channel can be freely checked every time. The subframe number indicated by the RRC signaling is measured and fed back; or when downlink traffic arrives and downlink channel detection is performed on the unlicensed frequency band (LBT mechanism based on LBE (Load Based Equipment)), that is, channel detection time Non-periodic occurrence, and there is no channel busy time in this case, because if the channel is busy, channel detection is always performed, then only channel detection time and channel idle time, if the channel is detected to be idle, then the base station can only After each time the channel is detected to be idle, a CSI measurement is set according to the start time and the end time of the channel idle. The time and frequency position are then used to inform the terminal CSI to measure the time and frequency position through RRC signaling, MAC (Medium access control) signaling or DCI (Downlink control indicator) signaling. How to inform the terminal of the CSI measurement time and frequency position under different LBT mechanisms and different channel states, so as to ensure the normal operation of CSI measurement and CSI feedback after the LTE system introduces the LBT mechanism in the unlicensed frequency band.

In the above technical solution, preferably, the control unit is further configured to: control, in a neighboring subframe after the channel detection time, to send CSI measurement configuration signaling and CSI feedback configuration signaling corresponding to the downlink channel busy state. Or when detecting that the downlink channel is idle, controlling to send a channel idle indication to the terminal, so that after receiving the channel idle indication, the terminal according to the received CSI measurement corresponding to the idle state of the downlink channel The configuration signaling and the CSI feedback configuration signaling perform the CSI measurement and the CSI feedback.

In the above technical solution, preferably, the control unit is further configured to: before receiving the CSI feedback, control CSI information of the adjacent time fed back by the stored terminal as the current CSI information, or control the lowest The modulation coding mode, or the control adopts the RRM measurement result according to the cell to which the base station belongs, the RRM measurement result of other cells adjacent to the cell, and the current state determined by the channel busy or switch state of the neighboring other cells. CSI information; and the controlling, using the stored CSI information of the adjacent time fed back by the terminal as the current CSI information specifically includes: when the CSI information of the adjacent time is the CSI information of the busy state of the channel, the control is according to the The CSI information of the adjacent time, the RSSI information at the time of channel detection corresponding to the CSI information of the adjacent time, and the RSSI information at the time of the current channel detection determine the current CSI information; or when the CSI of the adjacent time When the information is the CSI information of the downlink channel busy state, according to the RSRP information of the cell to which the base station belongs and the RSSI when the channel is currently detected. The information determines the current CSI information.

The CSI information of the adjacent time fed back by the terminal stored by the base station is used as the current CSI. The information specifically includes: if the latest interval time is short, and is also the CSI information of the downlink channel idle state; if the latest interval time is short, and the CSI information of the downlink channel busy state, according to the adjacent CSI information ( The old CSI information) and the RSSI (Received Signal Strength indication) information corresponding to the channel detection are combined with the RSSI information (new RSSI information) of the current channel detection to determine the current CSI information, for example, The current CSI information = (new RSSI / old RSSI) * old CSI, or the current CSI information is determined by using the RSRP information of the cell to which the base station belongs and the RSSI information when the current channel is detected, such as the current CSI information = the cell to which the base station belongs. RSRP / new RSSI.

According to still another aspect of the present invention, a base station is provided, the base station comprising a communication bus, an output device, a memory, and a processor, wherein:

The communication bus is configured to implement connection communication between the output device, the memory, and the processor;

The output device is configured to send CSI measurement configuration signaling and CSI feedback configuration signaling corresponding to a current downlink channel state, and send CSI measurement configuration signaling and CSI feedback configuration signaling corresponding to a specified downlink channel state;

The memory stores a set of program codes, and the processor calls the program code stored in the memory to perform the following operations:

When a downlink service arrives, detecting a current downlink channel state, and transmitting CSI measurement configuration signaling and CSI feedback configuration signaling corresponding to the current downlink channel state to the terminal by using the output device according to the current downlink channel state; or

When a downlink service arrives, the CSI measurement configuration signaling and the CSI feedback configuration signaling corresponding to the specified downlink channel state are sent to the terminal by the output device, so that the terminal according to the downlink channel after learning the downlink channel state. The CSI measurement configuration signaling and the CSI feedback configuration signaling corresponding to the state perform CSI measurement and CSI feedback.

In the above technical solution, preferably, the processor sends CSI measurement configuration signaling and CSI feedback configuration signaling corresponding to the current downlink channel state or CSI measurement configuration signaling and CSI corresponding to a specified downlink channel state. Before feedback configuration signaling, it is also used to perform the following operations:

CSI measurement configuration signaling and CSI feedback configuration signaling respectively corresponding to the downlink channel busy state and the downlink channel idle state are set.

In the above technical solution, preferably, the configuration content of the CSI measurement configuration signaling and the CSI feedback configuration signaling corresponding to the downlink channel busy state specifically includes: a first signal indicating that the terminal is used for CSI measurement, and the first CSI measurement time and frequency location, first CSI measurement period, first CSI feedback time, and first CSI feedback period;

The configuration content of the CSI measurement configuration signaling and the CSI feedback configuration signaling corresponding to the downlink channel idle state specifically includes: a second signal indicating the terminal for CSI measurement, a second CSI measurement time and frequency position, and a second CSI measurement period, second CSI feedback time, and second CSI feedback period.

In the above technical solution, preferably, the first signal indicating that the terminal is used for CSI measurement comprises one or a combination of the following: a PSS/SSS signal transmitted in a first cycle, and a CRS signal transmitted in a second cycle. a CSI-RS signal transmitted in a third cycle and a DRS signal transmitted in a fourth cycle;

The first CSI measurement time and frequency position is a transmission time and a frequency position of the first signal indicating that the terminal is used for CSI measurement;

The first CSI measurement period is greater than or equal to a maximum one of the first period, the second period, the third period, and the fourth period;

The first CSI feedback period is greater than or equal to the first CSI measurement period;

The second signal indicating that the terminal is used for CSI measurement includes one or a combination of the following: a PSS/SSS signal transmitted in a fifth cycle, a CRS signal transmitted in a sixth cycle, and a CSI transmitted in a seventh cycle. RS signal and DRS signal transmitted in the eighth cycle;

The second CSI measurement time and frequency location is provided by the second CSI measurement configuration signaling, indicating a subframe number and a subcarrier position used by the terminal for CSI measurement;

The second CSI measurement period is greater than or equal to a maximum one of the fifth period, the sixth period, the seventh period, and the eighth period;

The second CSI feedback period is greater than or equal to the second CSI measurement period, where the fifth period is less than or equal to the first period, the sixth period is less than or equal to the second period, The seventh period is less than or equal to the third period, the eighth period is less than or equal to the fourth period, and the second CSI measurement period is less than or equal to the first CSI measurement period, the second CSI feedback The period is less than or equal to the first CSI feedback period, and

The first CSI feedback time and the second CSI feedback time include: feedback when an uplink channel is detected to be idle, or direct feedback after the CSI measurement ends.

In the above technical solution, preferably, the processor is further configured to:

Transmitting CSI measurement configuration signaling and CSI feedback configuration signaling corresponding to the downlink channel busy state, the downlink channel idle state, and CSI feedback information on the unlicensed frequency band or the licensed frequency band.

When the channel detection is repeatedly performed in a fixed period on the unlicensed frequency band, the CSI measurement configuration information corresponding to the downlink channel busy state or the downlink channel idle state is directly sent to the terminal by means of RRC signaling. And CSI feedback configuration signaling; or

When receiving the downlink service, performing downlink channel detection on the unlicensed frequency band, and detecting that the downlink channel is idle, determining the CSI measurement time according to the start time and the end time of the downlink channel idle time. Frequency location, and transmitting CSI measurement configuration signaling and CSI feedback configuration signaling corresponding to the downlink channel idle state to the terminal by means of RRC signaling, MAC signaling, and/or DCI signaling.

Sending CSI measurement configuration signaling and CSI feedback configuration signaling corresponding to the downlink channel busy state in the adjacent subframe after the channel detection time; or

When detecting that the downlink channel is idle, sending a channel idle indication to the terminal, so that the terminal receives the channel idle indication, and according to the received CSI measurement configuration signaling corresponding to the downlink channel idle state. And performing the CSI measurement and the CSI feedback with CSI feedback configuration signaling.

Before receiving the CSI feedback, the stored CSI information of the adjacent time fed back by the terminal is used as the current CSI information, or the lowest modulation coding mode is adopted, or the RRM measurement result according to the cell to which the base station belongs is adopted, Other cells adjacent to the cell RRM measurement results and current CSI information determined by channel busy or switch state of the neighboring other cells;

The CSI information of the adjacent time fed back by the terminal as the current CSI information specifically includes:

When the CSI information of the adjacent time is the CSI information of the busy state of the channel, the CSI information of the adjacent time, the RSSI information of the channel detection corresponding to the CSI information of the adjacent time, and the current channel The RSSI information at the time of detection determines the current CSI information; or

When the CSI information of the adjacent time is the CSI information of the busy state of the channel, the current CSI information is determined according to the RSRP information of the cell to which the base station belongs and the RSSI information when the channel is currently detected.

In the technical solution, the CSI measurement and feedback system when the base station works in the unlicensed frequency band by the LTE system, when there is downlink service arrival, and when the downlink channel state is known, the CSI measurement corresponding to the current downlink channel state is The CSI feedback configuration signaling is sent to the terminal, or, when the downlink channel state is unknown, the CSI measurement and the CSI feedback configuration signaling corresponding to the specified downlink channel state are sent to the terminal, so that the terminal obtains the downlink channel state according to the corresponding The CSI measurement and the CSI feedback configuration signaling perform CSI measurement and CSI detection. Therefore, the CSI measurement and the CSI feedback can be effectively performed after the LBT mechanism is introduced in the unlicensed band of the LTE system, and the latest CSI information is not yet ensured. When obtained, the CSI information can be obtained, so that the base station can select a more suitable modulation and coding mode, and further improve the spectrum efficiency and channel usage.

The technical solution of the present invention can ensure that the CSI measurement and the CSI feedback are performed normally after the LBT mechanism is introduced in the unlicensed frequency band of the LTE system, and that the CSI information can be obtained when the latest CSI information is not obtained, thereby enabling The base station can select a more suitable modulation and coding scheme to further improve spectral efficiency and channel utilization.

DRAWINGS

Figure 1 shows a schematic diagram of two modes of operation of an unlicensed spectrum;

2 is a schematic diagram showing an interference avoidance rule of a Wi-Fi system;

FIG. 3 is a schematic diagram showing an LBT frame structure in LTE;

4 is a flow chart showing a CSI measurement and feedback method when an LTE system operates in an unlicensed band according to an embodiment of the present invention;

5 is a schematic diagram of CSI measurement under a frame structure based LBT mechanism when an LTE system operates in an unlicensed frequency band according to an embodiment of the present invention;

6 is a schematic diagram of CSI measurement under a load (data service) based LBT mechanism when an LTE system operates in an unlicensed band according to an embodiment of the present invention;

FIG. 7 is a schematic diagram showing a delay of measuring CSI by channel busy and idle according to an embodiment of the present invention; FIG.

FIG. 8 is a schematic diagram showing a time delay of measuring CSI when a channel is idle according to an embodiment of the present invention; FIG.

9 is a block diagram showing the structure of a CSI measurement and feedback system when an LTE system operates in an unlicensed band according to an embodiment of the present invention;

FIG. 10 is a schematic structural diagram of a base station according to an embodiment of the present invention; FIG.

FIG. 11 shows a schematic structural diagram of another base station according to an embodiment of the present invention.

detailed description

The above described objects, features and advantages of the present invention will become more apparent from the detailed description of the appended claims. It should be noted that the embodiments in the present application and the features in the embodiments may be combined with each other without conflict.

In the following description, numerous specific details are set forth in order to provide a full understanding of the invention, but the invention may be practiced otherwise than as described herein. Limitations of the embodiments.

4 is a flow chart showing a CSI measurement and feedback method when an LTE system operates in an unlicensed band according to an embodiment of the present invention.

As shown in FIG. 4, a CSI measurement and feedback method for an LTE system operating in an unlicensed band according to an embodiment of the present invention is used by a base station side, and includes: Step 402: When a downlink service arrives, detecting a current downlink channel state. And transmitting CSI measurement configuration signaling and CSI feedback configuration signaling corresponding to the current downlink channel state to the terminal according to the current downlink channel state; or transmitting, when a downlink service arrives, corresponding to the specified downlink channel state to the terminal CSI measurement configuration signaling and CSI feedback configuration signaling, so that the terminal is informed of the downlink channel state according to the next The CSI measurement configuration signaling and the CSI feedback configuration signaling corresponding to the channel channel state perform CSI measurement and CSI feedback.

In the above technical solution, preferably, CSI measurement configuration signaling and CSI feedback configuration signaling corresponding to the current downlink channel state or CSI measurement configuration signaling and CSI feedback configuration signaling corresponding to a specified downlink channel state are transmitted. The method further includes: setting CSI measurement configuration signaling and CSI feedback configuration signaling respectively corresponding to the downlink channel busy state and the downlink channel idle state.

In the technical solution, CSI measurement configuration signaling and CSI feedback configuration signaling corresponding to the downlink channel state (downlink channel busy and downlink channel idle), and CSI measurement configuration signaling and CSI feedback corresponding to the channel busy state are set. The configuration content of the configuration signaling includes, but is not limited to, a first signal indicating the CSI measurement by the terminal (a signal for CSI measurement), a first CSI measurement time and a frequency position, a first CSI measurement period, and a first CSI. The configuration of the CSI measurement configuration signaling and the CSI feedback configuration signaling corresponding to the downlink channel idle state includes, but is not limited to: a second signal indicating that the terminal is used for CSI measurement (for the feedback time and the first CSI feedback period) CSI measured signal), second CSI measurement time and frequency position, second CSI The measurement period, the second CSI feedback time, and the second CSI feedback period are corresponding to the CSI measurement and the feedback signaling, and the corresponding main content is configured to explicitly indicate whether the measurement is needed when the downlink channel state is different. And feedback CSI, and based on which information is used for CSI measurement and feedback, thereby effectively ensuring the normal operation of CSI measurement and CSI feedback after the LTE system introduces the LBT mechanism in the unlicensed frequency band.

In the above technical solution, preferably, the first signal indicating that the terminal is used for CSI measurement comprises one or a combination of the following: a PSS/SSS signal transmitted in a first cycle, and a CRS signal transmitted in a second cycle. a CSI-RS signal transmitted in a third period and a DRS signal transmitted in a fourth period; the first CSI measurement time and frequency position being a first transmission time of the signal indicating that the terminal is used for CSI measurement a frequency position; the first CSI measurement period is greater than or equal to a maximum one of the first period, the second period, the third period, and the fourth period; the first CSI feedback period is greater than Or equal to the first CSI measurement period; and the second signal indicating that the terminal is used for CSI measurement includes one or a combination of the following: a PSS/SSS signal sent in a fifth cycle, sent in a sixth cycle a CRS signal, a CSI-RS signal transmitted in a seventh period, and a DRS signal transmitted in an eighth period; the second CSI measurement time and frequency position being used to indicate the terminal for the second CSI measurement configuration signaling Measured at CSI a frame number and a subcarrier position; the second CSI measurement period is greater than or equal to a maximum one of the fifth period, the sixth period, the seventh period, and the eighth period; the second CSI The feedback period is greater than or equal to the second CSI measurement period, wherein the fifth period is less than or equal to the first period, the sixth period is less than or equal to the second period, and the seventh period is less than or Equal to the third period, the eighth period is less than or equal to the fourth period, the second CSI measurement period is less than or equal to the first CSI measurement period, and the second CSI feedback period is less than or equal to the first period A CSI feedback period, and the first CSI feedback time and the second CSI feedback time include: feedback when an uplink channel is detected to be idle, or direct feedback after the CSI measurement ends.

In this technical solution, the first indication terminal corresponding to the downlink channel busy state is used for CSI The measured signal includes, but is not limited to, one or a combination of the following: a PSS/SSS (Primary Synchronization Signal, Primary Synchronization Signal, Secondary Synchronization Signal) transmitted by the PSS transmitted in the first period (large period) according to the first period. a signal, a CRS (Common Reference Signal) signal transmitted in a second period (large period), a CSI-RS (Channel State Information-Reference Signal) signal transmitted in a third period, and The DRS (Discover Reference Signal) signal transmitted in the fourth period and the second indication terminal corresponding to the downlink channel idle state are used for CSI measurement, including but not limited to one or a combination of the following: The PSS/SSS signal transmitted in the period (small period), the CRS signal transmitted in the sixth period (small period), the CSI-RS signal transmitted in the seventh period (small period), and the transmission in the eighth period (small period) a DRS signal, wherein the first period, the second period, the third period, and the fourth period are not completely identical, and the fifth period, the sixth period, the seventh period, and the fourth The periods are not completely the same, and the fifth period, the sixth period, the seventh period, and the eighth period are respectively less than or equal to the first period, the second period, the third period, and the fourth period, respectively, that is, the method can be notified in multiple manners. The terminal performs CSI measurement and CSI feedback; and the start time of the CSI measurement and feedback corresponding to the downlink channel busy state and the downlink channel idle state (the first CSI measurement time and frequency position and the second CSI measurement time and frequency position) are indicating terminals respectively The transmission time of the signal used for CSI measurement and the subframe number and subcarrier position for CSI measurement given in the signaling; the CSI feedback period corresponding to the busy or idle state of the downlink channel is greater than the CSI measurement period, and the CSI measurement period is respectively And greater than or equal to a maximum one of the first period, the second period, the third period, and the fourth period, and a maximum one of the fifth period, the sixth period, the seventh period, and the eighth period; and CSI feedback can be performed when the uplink channel is idle or the channel state is uncertain. The CSI feedback time can be set arbitrarily. CSI measurement and CSI feedback are performed aperiodically. When the downlink channel state is known or unknown, CSI measurement and feedback can be performed based on which signals are explicitly determined, and the time and period of CSI measurement and feedback are clarified, thereby effectively Ensure that the CSI measurement and CSI feedback are performed normally after the LTE system introduces the LBT mechanism on the unlicensed band.

FIG. 5 is a schematic diagram of CSI measurement under a frame structure based LBT mechanism when an LTE system operates in an unlicensed band according to an embodiment of the present invention.

FIG. 6 is a diagram showing a frame structure in which channel detection time is repeatedly set in a fixed detection period according to an embodiment of the present invention.

In the above technical solution, preferably, when the channel detection is repeatedly performed on the unlicensed frequency band in a fixed period, the downlink channel busy state or the The CSI measurement configuration signaling and the CSI feedback configuration signaling of the downlink channel idle state; or when the downlink service is received, and downlink channel detection is performed on the unlicensed frequency band, and when the downlink channel is idle, Determining, according to the start time and the end time of the downlink channel idle, the CSI measurement time and frequency location, and transmitting, by using RRC signaling, MAC signaling, and/or DCI signaling, to the terminal, corresponding to the downlink channel. CSI measurement configuration signaling and CSI feedback configuration signaling in idle state.

In this technical solution, when downlink channel detection (based on FBE (Framed based equipment) LBT mechanism) is repeated in a fixed period on an unlicensed frequency band, as shown in FIG. 5, that is, the channel detection time is periodically repeated. At this time, the CSI measurement time and the frequency position, such as the subframe number, are relatively easy to indicate to the terminal, that is, the direct RRC (Radio Resource Connection) signaling can be indicated once, and then the channel is busy every time. The idle can be measured and fed back according to the subframe number indicated by the RRC signaling; or when downlink traffic arrives, and downlink channel detection is performed on the unlicensed frequency band (LBT mechanism based on LBE (Load based equipment) ), that is, the channel detection time occurs non-periodically, as shown in Figure 6, and there is no channel busy time in this case, because if the channel is busy, channel detection is always performed, then only channel detection time and channel idle time, if When the channel is detected to be idle, at this time, the base station can only follow the start time of the channel idle after each time the channel is detected to be idle. The end time is set to a CSI measurement time and frequency position, and then the terminal CSI measurement time and the terminal are notified by RRC signaling, MAC (Medium access control) signaling or DCI (Downlink control indicator) signaling. Frequency position In this way, it is ensured that the CSI measurement time and the frequency position are notified to the terminal under different LBT mechanisms and different channel states, thereby ensuring the normal operation of the CSI measurement and the CSI feedback after the LTE system introduces the LBT mechanism in the unlicensed frequency band.

FIG. 7 is a timing diagram showing the measurement of CSI by channel busy and idle according to an embodiment of the present invention.

FIG. 8 is a diagram showing a delay of measuring CSI when a channel is idle according to an embodiment of the present invention.

In this technical solution, when CSI is measured regardless of whether the downlink channel is busy or not, the base station may transmit a signal for measuring CSI in a neighboring subframe after the channel detection time, and the terminal may be adjacent to the subframe after the channel detection time. The frame measures CSI and performs feedback (this method is applicable to the FBE-based LBT mechanism); or, when the base station performs downlink channel detection and detects that the downlink channel is idle, it immediately sends a channel idle indication to enable the terminal to receive the channel. After the idle indication, the CSI measurement is performed immediately. At this time, the base station sends a signal for CSI measurement after the terminal receives the channel idle indication and the time required for the CSI measurement, that is, after the terminal just receives the channel idle indication. The signal when the CSI measurement is performed can also be transmitted (this method is applicable to the LBT mechanism based on FBE and LBE); thus, it is possible to transmit a signal indicating the terminal for CSI measurement in a suitable subframe to effectively reduce When the base station detects that the channel is idle and the terminal measures and reports the delay of the CSI, the terminal can measure and feed back the CSI as early as possible. Improve spectral efficiency and channel usage, as shown in Figures 7 and 8.

In the above technical solution, preferably, before the receiving the CSI feedback, the stored CSI information of the adjacent time fed back by the terminal is used as the current CSI information, or the lowest modulation coding mode is adopted, or RRM measurement result of the cell to which the base station belongs, RRM measurement result of other cells adjacent to the cell, and current CSI information determined by channel busy or switch state of the neighboring other cell; and the use of the stored The CSI information of the adjacent time fed back by the terminal as the current CSI information specifically includes: when the CSI information of the adjacent time is the CSI information of the busy state of the channel, according to the CSI information of the adjacent time, The RSSI information at the time of channel detection corresponding to the CSI information of the adjacent time and the RSSI information at the time of the current channel detection determine the current CSI information; or when the CSI information of the adjacent time is a busy state of the downlink channel In the CSI information, the current CSI information is determined according to the RSRP information of the cell to which the base station belongs and the RSSI information when the channel is currently detected.

The CSI information of the adjacent time fed back by the terminal stored by the base station as the current CSI information specifically includes: if the latest interval time is short, and is also the CSI information of the downlink channel idle state; if the latest interval time is short, Moreover, the CSI information of the downlink channel busy state is combined with the current channel according to the adjacent CSI information (old CSI information) and the RSSI (Received Signal Strength indication) information corresponding to the channel detection. RSSI information at the time of detection (new RSSI information) (The RSSI information at the time of channel detection may be that the terminal quantizes the detected RSSI to a value when the channel is detected to be idle, and the value is notified to the base station terminal. When it is idle, it is notified to the base station at the same time. In this case, the corresponding table in which the different RSSIs are quantized into different values needs to be defined. As shown in the following table, the threshold1 in the table is the parameter of the channel busy and idle. If it is greater than the parameter, Indicates that the channel is idle, and threshold 1<threshold 2<threshold 3) determines the current CSI information, for example, the current CSI information = (new RSSI/old RSSI) * old CSI, or use the RSRP information of the cell to which the base station belongs and the RSSI information of the current channel detection to determine the current CSI information, such as the current CSI information = the RSRP/new of the cell to which the base station belongs. RSSI.

FIG. 9 is a block diagram showing the structure of a CSI measurement and feedback system when an LTE system operates in an unlicensed band according to an embodiment of the present invention.

As shown in FIG. 9, a CSI measurement and feedback system 900 for an LTE system operating in an unlicensed band according to an embodiment of the present invention is used for a base station side, and includes: a control unit 902, configured to control when a downlink service arrives Detecting a current downlink channel state, and controlling to send CSI measurement configuration signaling and CSI feedback configuration signaling corresponding to the current downlink channel state to the terminal according to the current downlink channel state, or for controlling when a downlink service arrives Transmitting CSI measurement configuration signaling and CSI feedback configuration signaling corresponding to the specified downlink channel state to the terminal, so that the terminal, after learning the downlink channel state, configures signaling and CSI feedback configuration according to the CSI measurement corresponding to the downlink channel state. Signaling performs CSI measurement and CSI feedback.

In the above technical solution, preferably, the method further includes: a setting unit 904, configured to send CSI measurement configuration signaling and CSI feedback configuration signaling corresponding to the current downlink channel state or CSI measurement corresponding to a specified downlink channel state. Before configuring signaling and CSI feedback configuration signaling, CSI measurement configuration signaling and CSI feedback configuration signaling corresponding to the downlink channel busy state and the downlink channel idle state, respectively.

In the above technical solution, the setting unit 904 is specifically configured to: set the configuration content of the CSI measurement configuration signaling and the CSI feedback configuration signaling corresponding to the downlink channel busy state, where the first indication includes: a signal used by the terminal for CSI measurement, a first CSI measurement time and frequency position, a first CSI measurement period, a first CSI feedback time, and a first CSI feedback period; and setting a CSI measurement configuration letter corresponding to the downlink channel idle state And the configuration content of the CSI feedback configuration signaling specifically includes: a second signal indicating the terminal for CSI measurement, a second CSI measurement time and frequency position, a second CSI measurement period, a second CSI feedback time, and a second CSI Feedback cycle.

In the foregoing technical solution, preferably, the setting unit 904 is further configured to: set the first signal indicating that the terminal is used for CSI measurement, including one or a combination of the following: a PSS sent in a first cycle. An SSS signal, a CRS signal transmitted in a second period, a CSI-RS signal transmitted in a third period, and a DRS signal transmitted in a fourth period; setting the first CSI measurement time and frequency position as the first indication station Determining a transmission time and a frequency position of a signal used by the terminal for CSI measurement; setting the first CSI measurement period to be greater than or equal to the first period, the first a maximum one of the second period, the third period, and the fourth period; setting the first CSI feedback period to be greater than or equal to the first CSI measurement period; and setting the second indication to the terminal The signal measured at the CSI includes one or a combination of the following: a PSS/SSS signal transmitted in a fifth cycle, a CRS signal transmitted in a sixth cycle, a CSI-RS signal transmitted in a seventh cycle, and a transmission in an eighth cycle. a DRS signal; setting the second CSI measurement time and frequency location for the second CSI measurement configuration signaling, indicating a subframe number and a subcarrier position of the terminal for CSI measurement; setting the second CSI measurement period And greater than or equal to a maximum one of the fifth period, the sixth period, the seventh period, and the eighth period; setting the second CSI feedback period to be greater than or equal to the second CSI measurement period And wherein the fifth period is less than or equal to the first period, the sixth period is less than or equal to the second period, and the seventh period is less than or equal to the third period and the eighth period Less than or equal In the fourth period, the second CSI measurement period is smaller than the first CSI measurement period, the second CSI feedback period is less than or equal to a first CSI feedback period, and the first CSI feedback time and location are set. The second CSI feedback time includes: feedback when an uplink channel is detected to be idle, or direct feedback after the CSI measurement ends.

In the foregoing technical solution, the setting unit 904 is further configured to: set configuration content of CSI measurement configuration signaling and CSI feedback configuration signaling corresponding to the downlink channel busy state and the downlink channel idle state. Specifically, the CSI measurement and the CSI feedback are performed aperiodically.

In this technical solution, the signal indicating the CSI measurement by the first indication terminal corresponding to the downlink channel busy state includes but is not limited to one or a combination of the following: the PSS transmitted in the first period (large period) is sent in the first cycle. The PSS/SSS (Primary Synchronization Signal, Secondary Synchronization Signal) signal, the CRS (Common Reference Signal) signal transmitted in the second period (large period), according to the third period ( CSI-RS (Channel State Information-Reference Signal) signal transmitted in a large period) and DRS (Discovery Reference Signal) signal transmitted in a fourth period (large period), and a downlink channel The signal indicating the CSI measurement by the second indication terminal corresponding to the idle state includes but is not limited to one or a combination of the following: the PSS/SSS signal transmitted in the fifth period (small period), according to the sixth period (small period) The transmitted CRS signal, the CSI-RS signal transmitted in the seventh period (small period), and the DRS signal transmitted in the eighth period (small period), wherein the first period, the second period, the third period, and the fourth period Not identical, the fifth period, the sixth period, the seventh period, and the eighth period are not completely the same, and the fifth period, the sixth period, the seventh period, and the eighth period are respectively less than or equal to the first period, respectively The second period, the third period, and the fourth period, that is, the terminal can be notified to perform CSI measurement and CSI feedback in multiple manners; and the start time of the CSI measurement and feedback corresponding to the downlink channel busy state and the downlink channel idle state (first CSI measurement) The time and frequency position and the second CSI measurement time and frequency position are respectively the transmission time of the signal indicating the terminal for CSI measurement and the subframe number and subcarrier position for CSI measurement given in the signaling; and the downlink channel is busy Or the CSI feedback period corresponding to the downlink idle state is greater than the CSI measurement period, and the CSI measurement period is greater than or equal to the largest of the first period, the second period, the third period, and the fourth period, respectively. The period value and the largest one of the fifth period, the sixth period, the seventh period, and the eighth period; and the CSI feedback can be performed when the uplink channel is idle or the channel state is uncertain, that is, the CSI can be arbitrarily set. Feedback time; of course, CSI measurement and CSI feedback can also be performed non-periodically. When the channel state is known or unknown, CSI measurement and feedback can be performed based on which signals are explicitly determined, and the time of CSI measurement and feedback is clarified. And the period, which effectively ensures the normal operation of CSI measurement and CSI feedback after the LTE system introduces the LBT mechanism in the unlicensed band.

In the foregoing technical solution, the control unit 902 is specifically configured to: control, in the unlicensed frequency band or the licensed frequency band, to send a CSI measurement configuration information corresponding to the downlink channel busy state and the downlink channel idle state. The command and CSI feedback configuration signaling and CSI feedback information.

In the foregoing technical solution, the control unit 902 is further configured to: when the channel detection is repeatedly performed in a fixed period on the unlicensed frequency band, control is directly sent to the terminal by means of RRC signaling. Corresponding to the CSI measurement configuration signaling and the CSI feedback configuration signaling of the downlink channel busy state or the downlink channel idle state; or when receiving the downlink service, performing downlink channel detection on the unlicensed frequency band and After detecting the downlink channel empty In the idle time, the control determines the CSI measurement time and the frequency position according to the start time and the end time of the downlink channel idle, and sends the corresponding to the terminal by means of RRC signaling, MAC signaling, and/or DCI signaling. The CSI measurement configuration signaling and the CSI feedback configuration signaling of the downlink channel idle state.

In the foregoing technical solution, the control unit 902 is further configured to: control, in a neighboring subframe after the channel detection time, to send CSI measurement configuration signaling and a CSI feedback configuration signal corresponding to the downlink channel busy state. Or when the downlink channel is idle, the control sends a channel idle indication to the terminal, so that the terminal receives the channel idle indication according to the received CSI corresponding to the downlink channel idle state. The measurement configuration signaling, the CSI feedback configuration signaling, the CSI measurement, and the CSI feedback.

In this technical solution, when CSI is measured regardless of whether the downlink channel is busy or not, the base station may send a signal for measuring CSI in a neighboring subframe after the channel detection time, and the terminal may be in the letter. The adjacent subframes measure CSI and perform feedback after the channel detection time (this method is applicable to the FBE-based LBT mechanism); or, when the base station performs downlink channel detection and detects that the downlink channel is idle, immediately transmits a channel idle indication. So that the terminal performs CSI measurement immediately after receiving the channel idle indication. At this time, the base station sends a signal for CSI measurement after the terminal receives the channel idle indication and the time required for the CSI measurement, that is, After the terminal just receives the channel idle indication, the signal when the CSI measurement is performed can also be sent (this method is applicable to the LBT mechanism based on FBE and LBE); thus, it can be implemented to transmit the indication terminal for CSI in a suitable subframe. The measured signal is used to effectively reduce the delay time after the base station detects the channel idle and the terminal measures and feeds back the CSI, so that the terminal can measure and feed back CSI as early as possible, thereby improving spectrum efficiency and channel utilization.

In the above technical solution, preferably, the control unit 902 is further configured to: before receiving the CSI feedback, control, by using the stored CSI information of the adjacent time fed back by the terminal as current CSI information, or control adopting The lowest modulation coding mode, or the control is determined according to the RRM measurement result of the cell to which the base station belongs, the RRM measurement result of other cells adjacent to the cell, and the channel busy or switch state of the neighboring other cells. The current CSI information; and the control uses the stored CSI information of the adjacent time fed back by the terminal as the current CSI information, specifically: when the CSI information of the adjacent time is the CSI information of the busy state of the channel, The CSI information of the adjacent time, the RSSI information at the time of channel detection corresponding to the CSI information of the adjacent time, and the RSSI information at the time of the current channel detection determine the current CSI information; or when the adjacent time When the CSI information is the CSI information of the downlink channel busy state, according to the RSRP information of the cell to which the base station belongs and the R when the current channel is detected. The SSI information determines the current CSI information.

In this technical solution, before receiving the CSI that is newly measured and fed back by the terminal, the base station may obtain current CSI information (alternative CSI information) by using the following methods, including: using the neighboring time feedback of the terminal stored by the base station. CSI information (the most recent CSI information), or the RRM (Radio Resource Management) measurement result of the cell to which the base station belongs, the RRM measurement result of other cells adjacent to the cell, and the channel of the adjacent other cell The busy or switch state determines the current CSI information, such as the current CSI information = RSRP (Reference signal receiving power) of the current cell (the cell to which the base station belongs). Signal receiving power) / (RSRP of the current cell + RSRP of a cell that is relatively open in the open state); thus, the base station can even select a more suitable modulation and coding mode, or adopt the lowest modulation and coding mode.

FIG. 10 shows a schematic structural diagram of a base station according to an embodiment of the present invention.

As shown in FIG. 10, a base station 1000 according to an embodiment of the present invention includes: a CSI measurement and feedback system 900 when an LTE system according to any one of the above technical solutions operates in an unlicensed frequency band.

In the technical solution, the CSI measurement and feedback system 900 when the base station 1000 operates in the unlicensed frequency band by the LTE system, when there is downlink service arrival, and when the downlink channel state is known, the CSI corresponding to the current downlink channel state is used. The measurement and the CSI feedback configuration signaling are sent to the terminal, or, when the downlink channel state is unknown, the CSI measurement and the CSI feedback configuration signaling corresponding to the specified downlink channel state are sent to the terminal, so that the terminal obtains the downlink channel state according to the Corresponding CSI measurement and CSI feedback configuration signaling are used for CSI measurement and CSI detection. Therefore, the CSI measurement and CSI feedback can be effectively performed after the LTE system introduces the LBT mechanism in the unlicensed frequency band, and the latest CSI information is ensured. Alternate CSI information can be obtained when not obtained, so that the base station can select a more suitable modulation and coding mode, further improving spectral efficiency and channel utilization.

The embodiment of the present invention further provides a base station, and FIG. 11 is a schematic structural diagram of another base station according to an embodiment of the present invention. As shown, the base station may include: at least one output device 1103, at least one processor 1101, For example, the CPU, the memory 1104, and the at least one bus 1102, the processor 1101 can be combined with the CSI measurement and feedback system when the LTE system shown in FIG. 9 operates in an unlicensed band.

The bus 1102 is used to connect the output device 1103, the processor 1101, and the memory 1104.

The output device 1103 may specifically be a communication interface of the terminal, such as a network interface, and the network interface may include a standard wired interface or a wireless interface (such as a WI-FI interface), specifically for transmitting CSI measurement corresponding to the current downlink channel state. The signaling and CSI feedback configuration signaling are configured to transmit CSI measurement configuration signaling and CSI feedback configuration signaling corresponding to the specified downlink channel state.

The above memory 1104 may be a high speed RAM memory or a non-volatile memory such as a disk memory. The above memory 1104 is further configured to store a set of program codes, and the processor 1101 is configured to call the program code stored in the memory 1104 to perform the following operations:

When a downlink service arrives, the current downlink channel state is detected, and CSI measurement configuration signaling and CSI feedback configuration signaling corresponding to the current downlink channel state are sent to the terminal by using the output device according to the current downlink channel state. or

When a downlink service arrives, the CSI measurement configuration signaling and the CSI feedback configuration signaling corresponding to the specified downlink channel state are sent to the terminal by the output device 1103, so that the terminal is in the After learning the downlink channel state, CSI measurement and CSI feedback are performed according to CSI measurement configuration signaling and CSI feedback configuration signaling corresponding to the downlink channel state.

In an optional embodiment, the processor 1101 transmits CSI measurement configuration signaling and CSI feedback configuration signaling corresponding to the current downlink channel state or CSI measurement configuration signaling and CSI feedback corresponding to a specified downlink channel state. Before configuring signaling, it is also used to do the following:

In an optional embodiment, the configuration content of the CSI measurement configuration signaling and the CSI feedback configuration signaling corresponding to the downlink channel busy state specifically includes: a first signal indicating that the terminal is used for CSI measurement, and a first CSI measurement. Time and frequency location, first CSI measurement period, first CSI feedback time, and first CSI feedback period. as well as

In an optional embodiment, the first signal indicating that the terminal is used for CSI measurement includes one or a combination of the following: a PSS/SSS signal sent in a first cycle, a CRS signal sent in a second cycle, The CSI-RS signal transmitted in the third period and the DRS signal transmitted in the fourth period.

The first CSI measurement time and frequency position is a transmission time and a frequency position of the first signal indicating that the terminal is used for CSI measurement.

The first CSI measurement period is greater than or equal to a maximum one of the first period, the second period, the third period, and the fourth period.

The first CSI feedback period is greater than or equal to the first CSI measurement period. as well as

The second signal indicating that the terminal is used for CSI measurement includes one or a combination of the following: a PSS/SSS signal transmitted in a fifth cycle, a CRS signal transmitted in a sixth cycle, and a CSI transmitted in a seventh cycle. The RS signal and the DRS signal transmitted in the eighth cycle.

The second CSI measurement time and frequency location is provided by the second CSI measurement configuration signaling, indicating a subframe number and a subcarrier location used by the terminal for CSI measurement.

The second CSI measurement period is greater than or equal to the fifth period, the sixth period, and the The largest one of the seventh period and the eighth period.

The second CSI feedback period is greater than or equal to the second CSI measurement period, where the fifth period is less than or equal to the first period, the sixth period is less than or equal to the second period, The seventh period is less than or equal to the third period, the eighth period is less than or equal to the fourth period, and the second CSI measurement period is less than or equal to the first CSI measurement period, the second CSI feedback The period is less than or equal to the first CSI feedback period. as well as

In an optional embodiment, the configuration content of the CSI measurement configuration signaling and the CSI feedback configuration signaling corresponding to the downlink channel busy state and the downlink channel idle state specifically includes: performing the CSI measurement and the aperiodically CSI feedback.

In an optional embodiment, the processor 1101 is further configured to perform the following operations:

When the channel detection is repeatedly performed in a fixed period on the unlicensed frequency band, the CSI measurement configuration information corresponding to the downlink channel busy state or the downlink channel idle state is directly sent to the terminal by means of RRC signaling. Let the CSI feedback configuration signaling. or

When detecting that the downlink channel is idle, sending a channel idle indication to the terminal, so that after receiving the channel idle indication, the terminal is configured to be idle according to the received downlink channel. The CSI measurement configuration signaling and the CSI feedback configuration signaling of the state perform the CSI measurement and the CSI feedback.

Before receiving the CSI feedback, the stored CSI information of the adjacent time fed back by the terminal is used as the current CSI information, or the lowest modulation coding mode is adopted, or the RRM measurement result according to the cell to which the base station belongs is adopted, RRM measurement results of other cells adjacent to the cell and current CSI information determined by channel busy or switch state of the neighboring other cells. as well as

When the CSI information of the adjacent time is the CSI information of the busy state of the channel, the CSI information of the adjacent time, the RSSI information of the channel detection corresponding to the CSI information of the adjacent time, and the current channel The RSSI information at the time of detection determines the current CSI information. or

Specifically, the terminal introduced in the embodiment of the present invention may be used to implement some or all of the processes in the method embodiment introduced by the present invention in conjunction with FIG.

The technical solution of the present invention is described in detail with reference to the accompanying drawings, which can ensure the normal implementation of CSI measurement and CSI feedback after the introduction of the LBT mechanism in the unlicensed frequency band of the LTE system, and ensure that the replacement can be obtained when the latest CSI information is not obtained. The CSI information enables the base station to select a more suitable modulation and coding scheme to further improve spectral efficiency and channel utilization.

The above description is only the preferred embodiment of the present invention, and is not intended to limit the present invention, and various modifications and changes can be made to the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and scope of the present invention are intended to be included within the scope of the present invention.

Claims

A CSI measurement and feedback method for an LTE system operating in an unlicensed frequency band is used on a base station side, and includes:

When a downlink service arrives, detecting a current downlink channel state, and transmitting CSI measurement configuration signaling and CSI feedback configuration signaling corresponding to the current downlink channel state to the terminal according to the current downlink channel state; or

When a downlink service arrives, the CSI measurement configuration signaling and the CSI feedback configuration signaling corresponding to the specified downlink channel state are sent to the terminal, so that the terminal performs CSI measurement according to the downlink channel state after obtaining the downlink channel state. Configure signaling and CSI feedback configuration signaling for CSI measurement and CSI feedback.
The CSI measurement and feedback method when the LTE system operates in an unlicensed frequency band according to claim 1, wherein the CSI measurement configuration signaling and the CSI feedback configuration signaling or corresponding corresponding to the current downlink channel state are transmitted. Before specifying the CSI measurement configuration signaling and the CSI feedback configuration signaling of the downlink channel state, the method further includes:

CSI measurement configuration signaling and CSI feedback configuration signaling respectively corresponding to the downlink channel busy state and the downlink channel idle state are set.
The CSI measurement and feedback method when the LTE system operates in an unlicensed frequency band according to claim 2, wherein the configuration content of the CSI measurement configuration signaling and the CSI feedback configuration signaling corresponding to the downlink channel busy state is specific The method includes: first indicating, by the terminal, a signal for CSI measurement, a first CSI measurement time and frequency position, a first CSI measurement period, a first CSI feedback time, and a first CSI feedback period;

The configuration content of the CSI measurement configuration signaling and the CSI feedback configuration signaling corresponding to the downlink channel idle state specifically includes: a second signal indicating the terminal for CSI measurement, a second CSI measurement time and frequency position, and a second CSI measurement period, second CSI feedback time, and second CSI feedback period.
The CSI measurement and feedback method when the LTE system according to claim 3 operates in an unlicensed frequency band, characterized in that

The first signal indicating that the terminal is used for CSI measurement includes one or a combination of the following: a PSS/SSS signal transmitted in a first cycle, a CRS signal transmitted in a second cycle, a CSI-RS signal transmitted in a third cycle, and a DRS signal transmitted in a fourth cycle;

The first CSI measurement time and frequency position is a transmission time and a frequency position of the first signal indicating that the terminal is used for CSI measurement;

The first CSI measurement period is greater than or equal to a maximum one of the first period, the second period, the third period, and the fourth period;

The first CSI feedback period is greater than or equal to the first CSI measurement period;

The second signal indicating that the terminal is used for CSI measurement includes one or a combination of the following: a PSS/SSS signal transmitted in a fifth cycle, a CRS signal transmitted in a sixth cycle, and a CSI transmitted in a seventh cycle. RS signal and DRS signal transmitted in the eighth cycle;

The second CSI measurement time and frequency location is provided by the second CSI measurement configuration signaling, indicating a subframe number and a subcarrier position used by the terminal for CSI measurement;

The second CSI measurement period is greater than or equal to a maximum one of the fifth period, the sixth period, the seventh period, and the eighth period;

The second CSI feedback period is greater than or equal to the second CSI measurement period, where the fifth period is less than or equal to the first period, the sixth period is less than or equal to the second period, The seventh period is less than or equal to the third period, the eighth period is less than or equal to the fourth period, and the second CSI measurement period is less than or equal to the first CSI measurement period, the second CSI feedback The period is less than or equal to the first CSI feedback period, and

The first CSI feedback time and the second CSI feedback time include: feedback when an uplink channel is detected to be idle, or direct feedback after the CSI measurement ends.
The CSI measurement and feedback method when the LTE system operates in an unlicensed frequency band according to claim 2, wherein CSI measurement configuration signaling and CSI feedback corresponding to the downlink channel busy state and the downlink channel idle state are performed. The configuration content of the configuration signaling specifically includes: performing the CSI measurement and the CSI feedback aperiodically.
The CSI measurement and feedback method when the LTE system operates in an unlicensed frequency band according to any one of claims 2 to 5, characterized in that: transmitting, on the unlicensed frequency band or the licensed frequency band, corresponding to the downlink channel busy Status, CSI measurement configuration signaling and CSI feedback configuration signaling of the downlink channel idle state, and CSI feedback information.
The CSI measurement and feedback method when the LTE system according to any one of claims 2 to 5 operates in an unlicensed frequency band, wherein when channel detection is repeatedly performed in a fixed period on the unlicensed frequency band, Transmitting CSI measurement configuration signaling and CSI feedback configuration signaling corresponding to the downlink channel busy state or the downlink channel idle state to the terminal directly by means of RRC signaling; or

When receiving the downlink service, performing downlink channel detection on the unlicensed frequency band, and detecting that the downlink channel is idle, determining the CSI measurement time according to the start time and the end time of the downlink channel idle time. Frequency location, and transmitting CSI measurement configuration signaling and CSI feedback configuration signaling corresponding to the downlink channel idle state to the terminal by means of RRC signaling, MAC signaling, and/or DCI signaling.
The CSI measurement and feedback method when the LTE system operates in an unlicensed frequency band according to claim 7, wherein the adjacent subframe after the channel detection time transmits a CSI measurement configuration letter corresponding to the busy state of the downlink channel. And CSI feedback configuration signaling; or

When detecting that the downlink channel is idle, sending a channel idle indication to the terminal, so that the terminal receives the channel idle indication, and according to the received CSI measurement configuration signaling corresponding to the downlink channel idle state. And performing the CSI measurement and the CSI feedback with CSI feedback configuration signaling.
The CSI measurement and feedback method of the LTE system in the unlicensed frequency band according to claim 8, wherein the stored CSI information of the adjacent time fed back by the terminal is used as the CSI information before the CSI feedback is received. Current CSI information, or adopting the lowest modulation coding mode, or adopting RRM measurement results according to cells of the base station to which the base station belongs, RRM measurement results of other cells adjacent to the cell, and busy channels of the adjacent other cells Or current CSI information determined by the switch state;

The CSI information of the adjacent time fed back by the terminal as the current CSI information specifically includes:

When the CSI information of the adjacent time is the CSI information of the busy state of the channel, the CSI information of the adjacent time, the RSSI information of the channel detection corresponding to the CSI information of the adjacent time, and the current channel The RSSI information at the time of detection determines the current CSI information; or

When the CSI information of the adjacent time is the CSI information of the busy state of the channel, the current CSI information is determined according to the RSRP information of the cell to which the base station belongs and the RSSI information when the channel is currently detected.
A CSI measurement and feedback system for an LTE system operating in an unlicensed frequency band is used on a base station side, and includes:

a control unit, configured to: when a downlink service arrives, control to detect a current downlink channel state, and control to send CSI measurement configuration signaling and a CSI feedback configuration signal corresponding to the current downlink channel state to the terminal according to the current downlink channel state. Order; or

When the downlink service arrives, the control sends the CSI measurement configuration signaling and the CSI feedback configuration signaling corresponding to the specified downlink channel state to the terminal, so that the terminal corresponds to the downlink channel state after obtaining the downlink channel state. The CSI measurement configuration signaling and the CSI feedback configuration signaling perform CSI measurement and CSI feedback.
The CSI measurement and feedback system of the LTE system according to claim 10, wherein the LTE system operates in an unlicensed frequency band, and further includes:

a setting unit, configured to separately set CSI measurement configuration signaling and CSI feedback configuration signaling corresponding to the current downlink channel state or CSI measurement configuration signaling and CSI feedback configuration signaling corresponding to a specified downlink channel state, respectively CSI measurement configuration signaling and CSI feedback configuration signaling corresponding to the downlink channel busy state and the downlink channel idle state.
The CSI measurement and feedback system when the LTE system of the LTE system is operated in an unlicensed frequency band according to claim 11, wherein the setting unit is specifically configured to:

The configuration content of the CSI measurement configuration signaling and the CSI feedback configuration signaling corresponding to the busy state of the downlink channel specifically includes: a signal indicating the CSI measurement by the terminal, a first CSI measurement time and a frequency position, and a first a CSI measurement period, a first CSI feedback time, and a first CSI feedback period;

The configuration content of the CSI measurement configuration signaling and the CSI feedback configuration signaling corresponding to the downlink channel idle state includes: a second signal indicating the CSI measurement by the terminal, a second CSI measurement time and a frequency position, and a second Two CSI measurement periods, a second CSI feedback time, and a second CSI feedback period.
CSI measurement when the LTE system according to claim 12 operates in an unlicensed frequency band The quantity and feedback system is characterized in that the setting unit is further used for:

Setting the first signal indicating that the terminal is used for CSI measurement includes one or a combination of the following: a PSS/SSS signal transmitted in a first cycle, a CRS signal transmitted in a second cycle, and a CSI transmitted in a third cycle. - an RS signal and a DRS signal transmitted in a fourth cycle;

Setting the first CSI measurement time and frequency position as a transmission time and a frequency position of the first signal indicating that the terminal is used for CSI measurement;

Setting the first CSI measurement period to be greater than or equal to a maximum one of the first period, the second period, the third period, and the fourth period;

Setting the first CSI feedback period to be greater than or equal to the first CSI measurement period;

Setting the second signal indicating that the terminal is used for CSI measurement includes one or a combination of the following: a PSS/SSS signal transmitted in a fifth cycle, a CRS signal transmitted in a sixth cycle, and a CSI transmitted in a seventh cycle. - the RS signal and the DRS signal transmitted in the eighth cycle;

And setting, by the second CSI measurement time and frequency location, a subframe number and a subcarrier position that are provided by the terminal for CSI measurement provided by the second CSI measurement configuration signaling;

Setting the second CSI measurement period to be greater than or equal to a maximum one of the fifth period, the sixth period, the seventh period, and the eighth period;

Setting the second CSI feedback period to be greater than or equal to the second CSI measurement period, where the fifth period is less than or equal to the first period, the sixth period is less than or equal to the second period, The seventh period is less than or equal to the third period, the eighth period is less than or equal to the fourth period, and the second CSI measurement period is less than or equal to the first CSI measurement period, the second CSI The feedback period is less than or equal to the first CSI feedback period, and

Setting the first CSI feedback time and the second CSI feedback time includes: feeding back when detecting an uplink channel idle, or directly after the CSI measurement ends.
The CSI measurement and feedback system of the LTE system of the LTE system according to claim 11, wherein the setting unit is further configured to:

The configuration of the CSI measurement configuration signaling and the CSI feedback configuration signaling corresponding to the downlink channel busy state and the downlink channel idle state specifically includes: performing the CSI measurement and the CSI feedback aperiodically.
The LTE system according to any one of claims 11 to 14 is in an unlicensed frequency band The CSI measurement and feedback system is characterized in that the control unit is specifically configured to:

Controlling CSI measurement configuration signaling, CSI feedback configuration signaling, and CSI feedback information corresponding to the downlink channel busy state and the downlink channel idle state on the unlicensed band or the licensed band.
The CSI measurement and feedback system of the LTE system according to any one of claims 11 to 14 when operating in an unlicensed frequency band, wherein the control unit is further configured to:

When the channel detection is repeatedly performed in a fixed period on the unlicensed frequency band, the CSI measurement configuration corresponding to the downlink channel busy state or the downlink channel idle state is directly sent to the terminal by means of RRC signaling. Signaling and CSI feedback configuration signaling; or

When the downlink service is received, and downlink channel detection is performed on the unlicensed frequency band, and when the downlink channel is idle, the control determines the CSI measurement time according to the start time and the end time of the downlink channel idle. And the frequency location, and transmitting CSI measurement configuration signaling and CSI feedback configuration signaling corresponding to the downlink channel idle state to the terminal by means of RRC signaling, MAC signaling, and/or DCI signaling.
The CSI measurement and feedback system of the LTE system of the LTE system according to claim 16, wherein the control unit is further configured to:

Controlling, by the adjacent subframe after the channel detection time, CSI measurement configuration signaling and CSI feedback configuration signaling corresponding to the downlink channel busy state; or

When detecting that the downlink channel is idle, the control sends a channel idle indication to the terminal, so that the terminal receives the channel idle indication, and according to the received CSI measurement configuration information corresponding to the downlink channel idle state. And CSI feedback configuration signaling to perform the CSI measurement and the CSI feedback.
The CSI measurement and feedback system of the LTE system according to claim 17, wherein the control unit is further configured to:

Before receiving the CSI feedback, the CSI information of the adjacent time fed back by the terminal is used as the current CSI information, or the lowest modulation coding mode is adopted, or the RRM according to the cell to which the base station belongs is controlled. Measurement results, RRM measurement results of other cells adjacent to the cell, and current CSI information determined by channel busy or switch state of the neighboring other cells;

The controlling, by using the stored CSI information of the adjacent time fed back by the terminal as the current CSI information, specifically includes:

When the CSI information of the adjacent time is the CSI information of the busy state of the channel, controlling the CSI information according to the adjacent time, the RSSI information when the channel is detected corresponding to the CSI information of the adjacent time, and the current The RSSI information at the time of channel detection determines the current CSI information; or

When the CSI information of the adjacent time is the CSI information of the busy state of the channel, the current CSI information is determined according to the RSRP information of the cell to which the base station belongs and the RSSI information when the channel is currently detected.
A base station, comprising: a communication bus, an output device, a memory, and a processor, wherein:

The communication bus is configured to implement connection communication between the output device, the memory, and the processor;

The output device is configured to send CSI measurement configuration signaling and CSI feedback configuration signaling corresponding to a current downlink channel state, and send CSI measurement configuration signaling and CSI feedback configuration signaling corresponding to a specified downlink channel state;

The memory stores a set of program codes, and the processor calls the program code stored in the memory to perform the following operations:

When a downlink service arrives, detecting a current downlink channel state, and transmitting CSI measurement configuration signaling and CSI feedback configuration signaling corresponding to the current downlink channel state to the terminal by using the output device according to the current downlink channel state; or

When a downlink service arrives, the CSI measurement configuration signaling and the CSI feedback configuration signaling corresponding to the specified downlink channel state are sent to the terminal by the output device, so that the terminal according to the downlink channel after learning the downlink channel state. The CSI measurement configuration signaling and the CSI feedback configuration signaling corresponding to the state perform CSI measurement and CSI feedback.
The base station according to claim 19, wherein the processor transmits CSI measurement configuration signaling and CSI feedback configuration signaling corresponding to the current downlink channel state or a CSI measurement configuration corresponding to a specified downlink channel state. Before signaling and CSI feedback configuration signaling, it is also used to perform the following operations:

CSI measurement configuration signaling and CSI feedback configuration signaling respectively corresponding to the downlink channel busy state and the downlink channel idle state are set.
The base station according to claim 20, wherein the configuration content of the CSI measurement configuration signaling and the CSI feedback configuration signaling corresponding to the downlink channel busy state specifically includes: first indicating that the terminal is used for CSI measurement a signal, a first CSI measurement time and frequency location, a first CSI measurement period, a first CSI feedback time, and a first CSI feedback period;

The configuration content of the CSI measurement configuration signaling and the CSI feedback configuration signaling corresponding to the downlink channel idle state specifically includes: a second signal indicating the terminal for CSI measurement, a second CSI measurement time and frequency position, and a second CSI measurement period, second CSI feedback time, and second CSI feedback period.
The base station according to claim 21, characterized in that

The first signal indicating that the terminal is used for CSI measurement includes one or a combination of the following: a PSS/SSS signal transmitted in a first cycle, a CRS signal transmitted in a second cycle, and a CSI transmitted in a third cycle. An RS signal and a DRS signal transmitted in a fourth cycle;

The first CSI measurement time and frequency position is a transmission time and a frequency position of the first signal indicating that the terminal is used for CSI measurement;

The first CSI measurement period is greater than or equal to a maximum one of the first period, the second period, the third period, and the fourth period;

The first CSI feedback period is greater than or equal to the first CSI measurement period;

The second signal indicating that the terminal is used for CSI measurement includes one or a combination of the following: a PSS/SSS signal transmitted in a fifth cycle, a CRS signal transmitted in a sixth cycle, and a CSI transmitted in a seventh cycle. RS signal and DRS signal transmitted in the eighth cycle;

The second CSI measurement time and frequency location is provided by the second CSI measurement configuration signaling, indicating a subframe number and a subcarrier position used by the terminal for CSI measurement;

The second CSI measurement period is greater than or equal to a maximum one of the fifth period, the sixth period, the seventh period, and the eighth period;

The second CSI feedback period is greater than or equal to the second CSI measurement period, where the fifth period is less than or equal to the first period, the sixth period is less than or equal to the second period, The seventh period is less than or equal to the third period, and the eighth period is less than or equal to In the fourth period, the second CSI measurement period is less than or equal to the first CSI measurement period, and the second CSI feedback period is less than or equal to the first CSI feedback period, and

The first CSI feedback time and the second CSI feedback time include: feedback when an uplink channel is detected to be idle, or direct feedback after the CSI measurement ends.
The base station according to claim 20, wherein the configuration content of the CSI measurement configuration signaling and the CSI feedback configuration signaling corresponding to the downlink channel busy state and the downlink channel idle state specifically includes: performing aperiodically The CSI measurement and the CSI feedback.
The base station according to any one of claims 20 to 23, wherein the processor is further configured to perform the following operations:

Transmitting CSI measurement configuration signaling and CSI feedback configuration signaling corresponding to the downlink channel busy state, the downlink channel idle state, and CSI feedback information on the unlicensed frequency band or the licensed frequency band.
The base station according to any one of claims 20 to 23, wherein the processor is further configured to perform the following operations:

When the channel detection is repeatedly performed in a fixed period on the unlicensed frequency band, the CSI measurement configuration information corresponding to the downlink channel busy state or the downlink channel idle state is directly sent to the terminal by means of RRC signaling. And CSI feedback configuration signaling; or

When receiving the downlink service, performing downlink channel detection on the unlicensed frequency band, and detecting that the downlink channel is idle, determining the CSI measurement time according to the start time and the end time of the downlink channel idle time. Frequency location, and transmitting CSI measurement configuration signaling and CSI feedback configuration signaling corresponding to the downlink channel idle state to the terminal by means of RRC signaling, MAC signaling, and/or DCI signaling.
The base station according to claim 25, wherein the processor is further configured to:

Sending CSI measurement configuration signaling and CSI feedback configuration signaling corresponding to the downlink channel busy state in the adjacent subframe after the channel detection time; or

When detecting that the downlink channel is idle, sending a channel idle indication to the terminal, so that the terminal receives the channel idle indication, and according to the received CSI measurement configuration signaling corresponding to the downlink channel idle state. Performing the CSI measurement and the CSI with CSI feedback configuration signaling Feedback.
The base station according to claim 26, wherein the processor is further configured to:

Before receiving the CSI feedback, the stored CSI information of the adjacent time fed back by the terminal is used as the current CSI information, or the lowest modulation coding mode is adopted, or the RRM measurement result according to the cell to which the base station belongs is adopted, RRM measurement results of other cells adjacent to the cell and current CSI information determined by channel busy or switch state of the neighboring other cells;

The CSI information of the adjacent time fed back by the terminal as the current CSI information specifically includes:

When the CSI information of the adjacent time is the CSI information of the busy state of the channel, the CSI information of the adjacent time, the RSSI information of the channel detection corresponding to the CSI information of the adjacent time, and the current channel The RSSI information at the time of detection determines the current CSI information; or

When the CSI information of the adjacent time is the CSI information of the busy state of the channel, the current CSI information is determined according to the RSRP information of the cell to which the base station belongs and the RSSI information when the channel is currently detected.