KR20160093533A - Method and Device for Measuring and Reporting Channel State Information - Google Patents

Abstract

The present disclosure relates to a 5G or pre-5G communication system which will be provided to support a higher data transmission rate after a 4G communication system, such as LTE. The present application discloses a method and device for measuring and reporting Channel State Information (CSI). A method for measuring and reporting CSI according to an embodiment comprises the steps of: measuring, by User Equipment (UE), CSI in multiple types of downlink signals; and feeding back, by the UE, the CSI measured based on the multiple types of downlink signals. According to embodiments of the present invention, CSI can be measured in a number of types of downlink signals, opportunities for the UE to measure CSI can be increased, accuracy of measurement of CSI can be improved, and the most efficient CSI can be fed back.

Description

Field of the Invention [0001] The present invention relates to a method and a device for measuring and reporting channel status information,

The present disclosure relates to the field of wireless communication technology, and more particularly, to a method, a user device, and a base station for feedback of channel state information (CSI).

Efforts have been made to develop an improved 5G (5 ^th -Generation) communication system or a pre-5G communication system to meet the increasing demand for wireless data traffic after commercialization of 4G (4 ^th -Generation) communication system . For this reason, the 5G communication system or the pre-5G communication system is called a system after the 4G network (Beyond 4G network) communication system or after the LTE system (Post LTE).

To achieve a high data rate, 5G communication systems are being considered for implementation in very high frequency (mmWave) bands (e.g., 60 gigahertz (60GHz) bands). In order to alleviate the path loss of the radio wave in the very high frequency band and to increase the propagation distance of the radio wave, the 5G communication system uses beamforming, massive multi-input multi-output (massive MIMO) (FD-MIMO), array antennas, analog beam-forming, and large scale antenna technologies are being discussed.

In order to improve the network of the system, the 5G communication system has developed an advanced small cell, an advanced small cell, a cloud radio access network (cloud RAN), an ultra-dense network, (D2D), a wireless backhaul, a moving network, cooperative communication, Coordinated Multi-Points (CoMP), and interference cancellation Have been developed.

In addition, in the 5G system, the Advanced Coding Modulation (ACM) scheme, Hybrid FSK and QAM Modulation (FQAM) and Sliding Window Superposition Coding (SWSC), the advanced connection technology, Filter Bank Multi Carrier (FBMC) (non-orthogonal multiple access), and SCMA (sparse code multiple access).

Due to the sharp clashes and explosion of spectrum resources among the explosive demands of users in high-bandwidth wireless services, the mobile operators have made unlicensed bands as complementary to licensed bands, And to begin using them. Therefore, placing the LTE in the unlicensed bands has been treated as an agenda.

Figure 1 shows a schematic diagram of aggregation of the applied and unenergized bands.

As shown in FIG. 1, a plurality of small cells or wireless fidelity (WiFi) access points (APs) may exist within a coverage of a macro cell. These small cells or WiFi APs may use authorized bands and unauthorized bands (i.e., grant bands and unlicensed bands) in a carrier aggregation manner. The 3rd Generation Partnership Project (3GPP) can use the efficient carrier aggregation of the unlicensed and authorized bands, without seriously affecting other technologies of the unlicensed band, I have begun to study whether it can be improved.

In general, the unlicensed bands have been distributed for some other uses, such as radar or WiFi of the 802.11 series. As described above, the level of interference in the unlicensed bands is not determined, so it is not easy to ensure that LTE transmissions guarantee a good Quality of Service (QoS). However, the unlicensed bands may be used for data transmission requiring at least a low QoS. Here, the LTE system arranged in the unlicensed band is referred to as an LTE-U system. How to prevent radios or other wireless systems such as WiFi and LTE-U systems from interfering with each other is an important issue. Clear Channel Assessment (CCA) is a commonly used mechanism in the unlicensed bands to avoid collisions. A station (STA) must detect a radio channel before transmitting signals and can occupy the radio channel and transmit signals only when it detects that the radio channel is idle. The LTE-U must also follow a similar mechanism to ensure low interference with other signals such as: A relatively easy way is for the LTE-U device (base station or terminal user) to dynamically switch according to the CCA results. That is, transmission is performed when it is monitored that the channel is idle, and the transmission is not performed when the channel is busy.

In the LTE system, particularly in the downlink, the UE reports downlink channel state information (CSI) to the base station in order to support a link self-adaptation function at the base station side Needs to be. The UE includes a cell specific reference signal (CRS), a non-zero power channel state information reference signal (NZP-CSI-RS), or a zero-power CSI-RS (CSI-RS: Zero-Power CSI-RS), and reports a channel quality indicator (CQI) to the BS. The UE may periodically report the CQI or may report the CQI non-periodically under triggering of the base station. The current downlink pilot signals for measuring the channel quality are periodically transmitted. Thus, the UE may acquire and combine one or more samples of the channel quality based on these signals to generate a corresponding CQI to be reported to the base station.

Since in the unlicensed bands, the LTE-U device switches to congestion according to the CCA results to determine whether to transmit signals, the LTE-U device can transmit any signal over a long period of time Therefore, the UE can not measure the channel strength of the CSI based on the pilot signal. If the CQI reported by the UE is based on the channel strength measured long time ago, the channel strength at the time the UE reports the CQI can not be accurately reflected. In addition, other wireless communication systems around the base station are generally in a temporarily closed state in which no signal is transmitted when the UE is scheduled by the LTE-U base station, The levels of interference in these two situations are different because communication systems may be in an open state in which signals are transmitted when the LTE-U base station does not occupy carrier resources in unlicensed bands. The CQI can provide a more accurate reference for scheduling the base station only if the CQI reported by the UE can accurately reflect the channel quality at the time the LTE-U base station schedules the UE. To help the base station schedule users with high efficiency, it is still a problem that the CQI reported by the UE at the time the LTE-U base station schedules the UE accurately reflects the channel quality .

It should be noted that the foregoing description of the prior art section has been presented solely for the purpose of clearly and completely illustrating the technical solution of the present invention and for the purpose of enabling the understanding of those skilled in the art . The technical solutions as described above should not be considered to be merely known to those skilled in the art since such solutions are described in the prior art section of the present invention.

The present application provides a method and a user terminal for measuring and reporting channel state information (CSI).

The present application provides a method and device for measuring and reporting CSI in a Long Term Evolution (LTE) system.

In one aspect, a method is provided for measuring and reporting channel state information (CSI). The method comprises: measuring a CSI in a plurality of downlink signals by a user terminal (UE); And feedback the measured CSI based on the plurality of types of downlink signals by the UE.

In some embodiments, the CSI is measured based on at least one type of downlink signals, wherein the at least one type of downlink signals are selected by the base station within a time period in which the base station transmits downlink data A reference signal for CSI measurement to be transmitted; A discovery reference signal (DRS) transmitted by the base station; And is selected from the group consisting of a reference signal specified by the CSI measurement and transmitted by the base station.

In some embodiments, the method further comprises: indicating to the base station that the CSI is not valid if the UE does not receive any signal transmitted by the base station within a predetermined time period ; Otherwise, the UE indicates the current channel interference level to the base station. In some embodiments, the step of the UE indicating the current channel interference level to the base station comprises: determining whether a signal transmitted by the base station is a window configured by the base station to measure the CSI, And feeding back a pure interference level indicator to the base station only when the base station does not receive the interference level indicator.

In some embodiments, the step of measuring the CSI based on the DRS transmitted by the base station comprises: directly using the DRS as a reference signal for the CSI measurement; Using a plurality of reference signal ports included in the DRS after the extension of the DRS; And performing the CSI measurement based on the reference signal for CSI measurement configured in the DRS through high layer signaling.

In some embodiments, the step of using a plurality of reference signal ports included in the DRS after the extension of the DRS includes: expanding and including all or a part of sub-frames of the DRS for CSI measurement Using multiple CRS ports; And using a plurality of CSI-RS ports extended and included in all or a part of sub-frames of the DRS for the CSI measurement.

In some embodiments, the higher layer signaling comprises a cycle, an offset and a duration of a cell common reference signal for the CSI measurement.

In some embodiments, the step of the UE feedbacking the measured CSI based on the multiple types of downlink signals may include: occupying the same resource to feed back multiple CSIs of the unlicensed band The method comprising: feeding back the CSI according to a predetermined priority, the predetermined priority being a priority of the CSI measured based on the plurality of types of downlink signals, ; The CSI report type has the highest priority and the priority of the validity of the CSI measured based on the plurality of types of downlink signals is lower than the priority of the CSI report type .

In some embodiments, the step of the UE feedbacking the measured CSI based on the plurality of types of downlink signals comprises: feeding back the CSI of the unlicensed band and the CSI of the licensed band Determining the priority according to the type of the band if occupation of the same resource occurs; And arranging the CSI of the unlicensed band and the CSI of the applied band according to the validity, and the CSI of the applied band has a predetermined validity.

In some embodiments, the predetermined validity of the CSI of the applied band is: the validity of the CSI of the applied band is higher than the CSI of the unlicensed band measured based on the downlink signals of the plurality of types; The validity of the CSI of the applied band is lower than the CSI of the unlicensed band measured based on the downlink signals of the plurality of types; The validity of the CSI of the applied band is lower than the CSI of the unlicensed band measured based on the downlink signals of the plurality of types but is higher than the CSI measured based on the reference signal specific to the DRS and CSI measurements .

In some embodiments, the step of the UE feedbacking the CSI measured based on the plurality of types of downlink signals further comprises: the UE reporting the identification information of the feedback CSI, Wherein the information comprises at least one of a corresponding cell identifier, a CSI process identifier and a CSI validity type.

In some embodiments, the step of the UE feedbacking the CSI measured based on the plurality of types of downlink signals comprises: feeding back only the CSI measured based on one type of downlink signal in one CSI process Further comprising the steps of:

In some embodiments, the step of the UE feedbacking the CSI measured based on the plurality of types of downlink signals comprises: feeding back the CSI measured based on the plurality of types of downlink signals in one CSI process Further comprising the steps of:

In some embodiments, when feeding back the CSI measured based on the plurality of types of downlink signals in the one CSI process, the interference component of the CSI measurement is: only in subframes of the same type of signal, A method of performing an averaging operation on the measurement of components; A method in which no averaging operation is performed on the measurement of the interference component; And performing a weighted average on the measurement of the interference component based on interference levels corresponding to other types of downlink signals.

In some embodiments, when feeding back the CSI measured based on the multiple types of downlink signals in one CSI process, the compensating operation may be performed based on the interference levels corresponding to the different types of downlink signals. And is performed on CSI measured based on other types of downlink signals.

In some embodiments, the compensating operation may comprise: determining whether the UE determines its interference level A in a period in which the base station transmits downlink data, and a period during which the base station transmits a reference signal specific to the DRS or CSI measurement And then the UE compensates for the signal-to-noise ratio obtained from the CSI measurements of the UE according to the interference level A and the interference level B; The power of the channel component obtained from the CSI measurement corresponding to the high interference level is increased by a predetermined value or the power of the interference component obtained from the CSI measurement corresponding to the high interference level is increased by the predetermined By a predetermined value.

In some embodiments, the step of the UE feedbacking the CSI measured based on the plurality of types of downlink signals may comprise: determining, based on the signal type based on the most recently reported Rank Indication (RI) A method of feeding back a pre-coded matrix indicator / channel quality indicator (PMI / CQI) of all bandwidth parts (BPs) over the entire bandwidth based on a signal of the same type and; A method of feeding back the PMI / CQI of each BP based on the downlink signal of the channel most recently occupied by the base station, wherein RI is assumed to be equal to the most recently reported RI; A method of feeding back the PMI / CQI of each BP based on the downlink signal of the channel most recently occupied by the base station when the priority of the new signal type useful for measuring the CSI is higher than the previous signal type, Where RI is assumed to be the same as the most recently reported RI; CQI of each BP from a physical uplink control channel (PUCCH) resource satisfying a process delay when a priority of a new signal type useful for measuring the CSI is higher than a previous signal type. And feeding back the RI and the PMI / CQI of the subbands of each BP according to any one of the methods of feeding back the measured RI based on the new signal type.

In a second aspect, a method of receiving channel state information (CSI) is provided. The method includes: transmitting a plurality of types of downlink signals for CSI measurement; And receiving a CSI fed back from a user equipment (UE) and measured based on the plurality of types of downlink signals.

In some embodiments, the multiple types of downlink signals include: a reference signal for CSI measurements transmitted within a time period in which the base station transmits downlink data; A discovery reference signal (DRS); And a reference signal specific to the CSI measurement.

In some embodiments, the step of transmitting the DRS for the CSI measurement comprises: directly using the DRS as a reference signal for the CSI measurement; Expanding the DRS to include a plurality of reference signal ports for CSI measurement; And configuring a reference signal for the CSI measurement in the DRS through higher layer signaling.

In some embodiments, the process of receiving the CSI fed back by the UE and measured based on the plurality of types of downlink signals comprises: measuring one type of downlink signal on one CSI process Receiving only the CSI; Or receiving a CSI measured based on the plurality of types of downlink signals in one CSI process.

In some embodiments, upon receiving the CSI measured based on the multiple types of downlink signals in the one CSI process, the method further comprises: determining, based on the interference levels corresponding to the different types of downlink signals, Configuring signal power estimates of the CSI measurements based on each of the other types of downlink signals; Or instructing the UE to increase the power of the channel component obtained from the CSI measurement corresponding to the high interference level by a predetermined value or to increase the power of the interference component obtained from the CSI measurement corresponding to the high interference level And decreasing the value of the second threshold value by the predetermined value.

In a third aspect, a user terminal is provided. The user terminal comprising a receiver, a transmitter and a processor, the receiver being configured to receive a plurality of types of downlink signals from a base station; Wherein the processor is configured to measure channel state information (CSI) in the plurality of types of downlink signals; And the transmitter is configured to feed CSI measured based on the plurality of types of downlink signals to the base station.

In a fourth aspect, a base station is provided. The base station comprising a receiver, a transmitter and a processor, the transmitter being configured to transmit a plurality of types of downlink signals for CSI measurements under the control of the processor; The receiver is configured to receive the CSI fed back by a user equipment (UE) and measured based on a plurality of types of downlink signals.

It should be noted that the corresponding embodiments of the first aspect can also be applied to the second aspect. Similarly, it should be noted that the corresponding embodiments of the second aspect can also be applied to the fourth aspects.

The particular embodiment described in accordance with the present application makes it possible for the UE to increase the opportunities for measuring CSI, improve the accuracy of the CSI measurement, and feed back the most effective CSI.

Further aspects, features and advantages of the present invention as set forth above will become more apparent from the following description, taken in conjunction with the accompanying drawings, in which certain preferred embodiments of the invention are described.
Figure 1 shows a schematic diagram of the aggregation of the applied and non-applied bands.
2 is a diagram illustrating a CSI measurement and reporting method in accordance with an embodiment of the present application.
Figure 3 shows a schematic diagram of the structure of the DRS.
Figure 4 shows a schematic diagram of a preferred structure in which the DRS extends to include a plurality of CRS ports.
Figure 5 shows a schematic diagram of another preferred structure in which the DRS extends to include a plurality of CRS ports.
Figure 6 shows a schematic diagram of another preferred structure in which the DRS extends to include a plurality of CRS ports.
Figure 7 shows a schematic diagram of another preferred structure in which the DRS extends to include a plurality of CRS ports.
8 shows a schematic diagram of the interference distribution of the UE when the base station transmits downlink signals in different scenes.
Figure 9 shows a preferred schematic diagram for feeding back P-CSI based on priority.
Figure 10 illustrates situations that may occur when CSI is fed back due to CSI being measured based on different types of signals.
Figure 11 shows a preferred schematic diagram for feeding back the RI and each BP.
Fig. 12 shows a preferred schematic diagram for feeding back the other RI and each BP.
Figure 13 shows a preferred schematic diagram for feeding back the other RIs and each BP.
Figure 14 shows a schematic flow chart of a method for receiving CSI according to an embodiment of the present application.
Figure 15 shows a schematic view of a device that can be used to implement the preferred embodiment of the present application.
Throughout the drawings, it should be noted that like reference numerals are used to illustrate the same or similar elements and features and structures.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

In the following description of the embodiments of the present invention, descriptions of techniques which are well known in the technical field of the present invention and are not directly related to the present invention will be omitted. This is for the sake of clarity of the present invention without omitting the unnecessary explanation.

For the same reason, some of the components in the drawings are exaggerated, omitted, or schematically illustrated. Also, the size of each component does not entirely reflect the actual size. In the drawings, the same or corresponding components are denoted by the same reference numerals.

BRIEF DESCRIPTION OF THE DRAWINGS The advantages and features of the present invention and the manner of achieving them will become apparent with reference to the embodiments described in detail below with reference to the accompanying drawings. The present invention may, however, be embodied in many different forms and should not be construed as being limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the concept of the invention to those skilled in the art. Is provided to fully convey the scope of the invention to those skilled in the art, and the invention is only defined by the scope of the claims. Like reference numerals refer to like elements throughout the specification.

It will be appreciated that the combinations of blocks and flowchart illustrations in the process flow diagrams may be performed by computer program instructions. These computer program instructions may be loaded into a processor of a general purpose computer, special purpose computer, or other programmable data processing apparatus, so that those instructions, which are executed through a processor of a computer or other programmable data processing apparatus, Thereby creating means for performing functions. These computer program instructions may also be stored in a computer usable or computer readable memory capable of directing a computer or other programmable data processing apparatus to implement the functionality in a particular manner so that the computer usable or computer readable memory The instructions stored in the block diagram (s) are also capable of producing manufacturing items containing instruction means for performing the functions described in the flowchart block (s). Computer program instructions may also be stored on a computer or other programmable data processing equipment so that a series of operating steps may be performed on a computer or other programmable data processing equipment to create a computer- It is also possible for the instructions to perform the processing equipment to provide steps for executing the functions described in the flowchart block (s).

In addition, each block may represent a module, segment, or portion of code that includes one or more executable instructions for executing the specified logical function (s). It should also be noted that in some alternative implementations, the functions mentioned in the blocks may occur out of order. For example, two blocks shown in succession may actually be executed substantially concurrently, or the blocks may sometimes be performed in reverse order according to the corresponding function.

Herein, the term " part " used in the present embodiment means a hardware component such as software or an FPGA (Field-Programmable Gate Array) or ASIC (Application Specific Integrated Circuit) Lt; / RTI > However, 'part' is not meant to be limited to software or hardware. &Quot; to " may be configured to reside on an addressable storage medium and may be configured to play one or more processors. Thus, by way of example, 'parts' may refer to components such as software components, object-oriented software components, class components and task components, and processes, functions, , Subroutines, segments of program code, drivers, firmware, microcode, circuitry, data, databases, data structures, tables, arrays, and variables. The functions provided in the components and components may be further combined with a smaller number of components and components or further components and components. In addition, the components and components may be implemented to play back one or more CPUs in a device or a secure multimedia card.

Although specific embodiments of the present disclosure will be described in the context of an OFDM-based wireless communication system, the subject matter of the present disclosure is not limited to the communication systems and services described herein, And the scope of the present invention is not limited to the above-described embodiments, but may be practiced by those skilled in the art.

It should be noted that the above embodiments and the features of the embodiments of the present application can be combined without collision. Hereinafter, the present application will be described specifically with reference to the accompanying drawings associated with the above embodiments.

In the following description, a base station (BS) is an access device in which communication devices access the cellular network and is used to allocate communication resources to the communication devices. The base station may be one of the following physical devices: an enhanced Node B (eNB), a Node B, a wireless electrical access unit, a base station controller, a base transceiver station terminal, . The communication devices may be devices that are intended to access the service through an access network, and may be configured to communicate through the access network. For example, the communication devices may include a user terminal (UE), a mobile station (MS), a cellular phone, a smart phone, a computer, or a multimedia system providing communication functions, But is not limited thereto. In the following description, it should be noted that the terms "communication apparatus", "user equipment" and "user terminal" may be used interchangeably.

Although each embodiment is described herein in a cell network of the LTE / LTE-A type for illustrative purposes, those skilled in the art will appreciate that the disclosed embodiments may be applied to other types of cellular networks something to do. Those skilled in the art will appreciate that although it is primarily described below to measure and report CSI in the unlicensed bands, it is to be understood that the proposed technical solutions may be applied to measuring and reporting CSI in the bands of interest something to do. As an example, for some reason (e.g., discontinuous transmission), there may be a situation where no signal is transmitted in the grant bands, which is a long time driver. The technical solution provided by each embodiment can be applied to this situation.

In order to use the channel resources of the carrier in the unlicensed band, the UE needs to report the CSI as accurately as possible. One embodiment of the present application provides a way to handle CSI reporting.

In the unlicensed band, the LTE device must determine whether it is possible to occupy the channel according to the CCA result. Therefore, the time when the LTE device can occupy the channel is not determined, and the LTE device can not transmit any signal for a long time. As a result, the base station can not periodically transmit a reference signal for CSI measurement, and the CSI measurement in the UE may also be affected. In order to ensure the efficiency of measuring and reporting the CSI, it is necessary to obtain as many opportunities as possible to transmit the reference signal for CSI measurement. The reference signal for the CSI measurement may be a cell common reference signal (CRS), a channel state information reference signal (CSI-RS), or a newly defined reference signal structure. have.

2 is a diagram showing a preferred flow chart of a method for measuring and reporting the CSI according to an embodiment of the present application.

As shown in FIG. 2, the method includes a step 201 in which the UE measures the CSI in multiple types of downlink signals.

There may be multiple types of signals transmitted by the base station, which may be used for the CSI measurements.

The first type is a type in which a base station occupies a channel, transmits a downlink data signal, and transmits a reference signal for CSI measurement while transmitting data. At this time, on one side, the UE can receive the reference signal from the base station and perform the CSI measurement on the channel. On the other side, the interference of other devices for the UE relatively accurately reflects the interference received by the UE when receiving data. Thus, the CSI measurement has higher effectiveness.

The second type is a type in which the base station transmits a discovery reference signal (DRS). The function of the DRS includes providing a measure measured by the Radio Resource Management (RRM) of the UE. That is, even when the base station does not transmit data, the DRS must be transmitted at an arbitrary density. Here, in the LTE version 12, the DRS is transmitted in an arbitrary period and duration, which can be generally one to five frames. However, in the unlicensed band, the timing of transmitting the DRS can not be periodic due to the influence of the CCA, and the DRS can not be transmitted according to time when the channel is always busy. To support the CSI measurement, the DRS may be considered as a reference signal for measuring the CSI in one implementation. Alternatively, the reference signal for the CSI measurement may be transmitted in the channel occupancy time of the DRS.

The third type is a type in which the BS occupies a channel and can transmit only a reference signal specific to the CSI measurement. By using this method, the reference signal for the CSI measurement can be transmitted at a frequency that is faster than the frequency at which the DRS can be transmitted.

For the second type and third type of downlink signals, when the base station does not transmit signals on all subcarriers in the system bandwidth, the second and third types of downlink signals The transmit power will be lower than the signal power of the first type downlink signal. As a result, devices outside a small range of the base station attention can start to start signals due to the detection of the low interference level. That is, the level of interference that the UE receives from another device is higher than the level of interference of the first type. Thus, the CSI measurements (briefly referred to as CSI measurements of the second type and CSI of the third type, respectively) based on the downlink signals of the second and third types are intrinsically < RTI ID = These are measurements under circumstances where the base station does not transmit downlink data and is not very important. In the following description of the embodiments of the present application, the CSI measurement of the second type and the CSI measurement of the third type may be combined and, for example, may be considered to have the same priority. Alternatively, these two types of CSI measurements can be further distinguished. As an example, different priorities may be assigned to these two types. For convenience of explanation, these two types of measurements are considered as one type in the following description. It will be appreciated by those skilled in the art that the method can be easily extended to situations that distinguish between these two types of CSI measurements.

Substantially, the base station may occasionally occupy the channel and then transmit multiple types of signals. In one example, the base station transmits downlink data and simultaneously transmits DRS. Alternatively, the base station also transmits a reference signal specific to the CSI measurement when transmitting the DRS. At this time, these types of signals may also be classified according to the level of interference with the UE. For example, when the base station transmits downlink data and simultaneously transmits DRS, the interference of other devices with the UE reflects the interference received by the UE relatively accurately when receiving data. In this way, at this time, the CSI measurement and the CSI measurement based on the first type of downlink signal (briefly referred to as the first type of CSI measurement) can be considered as one type.

Alternatively, or additionally, if it is impossible for the base station to occupy the channel in a long time and transmit data signals, it is impossible to occupy the channel and transmit a reference signal specific to the DRS or CSI measurement, The CSI measured by the UE a long time ago can no longer reflect the channel state at the time when the UE reports the CSI. Therefore, the above information is invalid information. At this time, the UE can transmit a CQI index 0 (OOR) to indicate an invalid CQI. Alternatively, the opportunity to report the CSI may also be used to report the level of current channel interference to provide some measure of the base station's scheduling. There may be other devices close to the base station because the base station has failed to transmit the downlink signals by occupying the channel and thus the level of interference received by the UE may be relatively high and the base station may not have three Lt; / RTI > may be higher than the situation of transmitting signals of the types.

Here, in some embodiments, a window of the CSI measurement may be configured. That is, if both the downlink data and the reference signal specific to the DRS and CSI measurements are not transmitted by the base station in this window, the UE reports only a pure indicator for the interference level. Alternatively, the UE may preferentially feed back CSI information measured during downlink data transmission of the base station or CSI information based on a reference signal specific to the DRS or CSI measurement.

In one implementation, this window can be determined for the subframe n where the CSI transmission is present, i.e., [ nW , nk ], where W-k + 1 is the number of subframes contained in this window , k is based on the process delay of the UE, for example, k = 4.

Alternatively, in other implementations, for aperiodic CSI, the window may also include a subframe m of an uplink grant (UL grant) that triggers aperiodically CSI: A-CSI I.e., [ mX , mx ], where X - x + 1 is the number of subframes contained in this window, and x is based on the process delay of the UE. If x> 0, the UE can use more time in processing, and if x <0, the CSI can be fed back more timely. Alternatively, x may be zero.

Referring back to FIG. 2, in step 202, the UE feeds back measured CSI based on multiple types of downlink signals.

According to the above analysis, the accuracy and efficiency of the CSI measured based on the signals of the plurality of types are different. Thus, the present application provides a method of processing CSI feedback.

Hereinafter, four preferred embodiments provided by the present application for processing CSI feedback are described.

First embodiment

In the first embodiment, how CSI measurements are performed based on the DRS transmitted by the base station is described.

In a carrier in the unlicensed band, the base station is determined whether the channel can be occupied according to the CCA result. After the channel is occupied by the base station for a period of time, the base station must release the channel in accordance with the European regulations that the time occupied by the channel should not exceed 13 ms. In this way, the base station may not be able to occupy the channel for a long time, and may only last for a short time when occupying the channel. The measurement and reporting of the CSI by the UE when the base station transmits downlink data, although the CSI measurement measured at the time the base station transmitted the downlink data is most accurate, It can not be used to schedule downlink data. If the next time that the base station occupies the channel and transmits data occurs after a long time, this CSI information may expire. In addition, in order for the base station to occupy the channel and transmit the downlink data in a timely manner, it is necessary for the base station to acquire a relatively new CSI before transmitting the data. The base station can solve the above problem by integrating a reference signal for CSI measurement or transmitting a reference signal specific to CSI measurement when transmitting DRS. The reference signal for the CSI measurement may be CRS, CRS-RS, or a newly defined reference signal structure.

The limitations on transmitting the reference signal specific to the DRS and CSI measurements are relatively loose. For example, when the reference signal specific to the DRS and the CSI measurement is processed as a short control signal (SCS) according to European regulations, the base station can not generate the CCA, but the periodic occurrence of such signals So as to ensure that the CSI measurement can be adapted. Alternatively, the condition is much looser than the situation of transmitting the downlink data, although the base station still needs a CCA before transmitting these signals. In one example, the threshold of CCA detection is relatively high, and therefore the likelihood that the base station can transmit such signals is higher than the probability of transmitting downlink data, thus helping to provide more opportunities to measure the CSI . Also, although the transmission conditions and the reference signal specific to the DRS and CSI measurements are the same as the conditions for transmitting the downlink data, the use of such signals may also be beneficial. For example, in a relatively low load situation, the base station does not have current data, so the base station transmits only the reference signal specific to the DRS and / or CSI measurements and provides an opportunity to timely obtain the CSI can do. A processing method for performing CSI measurements based on the DRS transmitted by the base station according to some preferred embodiments will be described below.

The first method is to use the DRS transmitted by the base station as a reference signal for the CSI measurement.

Figure 3 shows a schematic diagram of the structure of the DRS.

As shown in FIG. 3, according to the definition in Release 12 (Rel 12), the DRS includes a plurality of types of signals: a primary simultaneous signal (PSS) (Secondary Simultaneous Signal (SSS) and CRS port 0). The base station may configure the DRS to include one NZP CSI-RS port. In this manner, the UE may measure the CSI using the CRS port 0 and / or the NZP CSI-RS port. In particular, signals of both types can be used for the CSI measurement. Alternatively, only one type of signal is used to measure the CSI. Alternatively, the CSI may also be measured according to the Transmission Mode (TM) of the UE. As an example, for TM 1 through TM 8, the CSI may be measured based on the CRS port 0. For TM 9, the channel portion of the CSI can be measured based on this NZP CSI-RS port, and the interference portion of the CSI can be measured based on the CSI Port 0 . For the TM 10, the channel component of the CSI can be measured based on this NZP CSI-RS port, and the interference component of the CSI is a resource element with a current cell power of 0 in the DRS sub- RE). &Lt; / RTI &gt; For example, the RE with the current cell power of 0 may denote all REs in which the current cell power is zero in the DRS subframes. Alternatively, the RE may be an interference measurement resource configured by higher layer signaling in one subframe among the subframes occupied by the DRS, for example, by reusing the method of configuring the ZP CSI-RS. Alternatively, the subframe in which the ZP CSI-RS exists may be a subframe including the NZP CSI-RS among the subframes occupied by the DRS.

The second method is to extend the structure of DRS defined by Rel-12 to include more reference signal ports for CSI measurements. That is, the UE measures the CSI using the extended DRS reference signal ports.

In one aspect, in order to support CSI measurements based on the plurality of CRS ports, the DRS may be extended to include a plurality of CRS ports. In some embodiments, the extension of the CSR port may be performed in all of the subframes occupied by the DRS.

In one implementation, the extended CRS port (s) can directly reuse existing CRS Port 1 through CRS Port 3 mapping structures in a subframe.

Figure 4 shows a schematic diagram of a preferred architecture for extending the DRS to include a plurality of CRS ports.

As shown in FIG. 4, if it is assumed that two CRS ports are required, CRS port 0 and CRS port 1 may be transmitted in the DRS.

Alternatively, in other implementations, the extended CRS port (s) may also be obtained by shifting existing CRS ports in the time domain.

Figure 5 shows a schematic diagram of another preferred structure for extending the DRS to include a plurality of CRS ports.

5, assuming that two CRS ports are required, the CRS port 0 is shifted right by one orthogonal frequency division multiplexing (OFDM) symbol to acquire a new port And the new port is different from each of the existing four CRS ports and is recorded with a CRS port x and is used to measure the channel of the CRS port 1. The use of this method may be beneficial in distributing multiple CRS ports of different OFDM symbols so that the transmission power is not increased when multiple CRS ports are transmitted, or the transmission power is increased as low as possible.

In Figures 4 and 5, it is assumed that the expansion of the CRS port can be performed in all of the subframes occupied by the DRS. Alternatively, in other embodiments, only some of the subframes occupied by the DRS are extended to include a plurality of CRS ports. In one example, the expansion of the CRS port is performed in only one of the subframes occupied by the DRS. These subframes, which are extended to include CRS ports, can be configured semi-fixed or fixed by the higher layer signaling. For example, the subframe including the PSS / SSS performs CRS extension.

FIG. 6 shows a schematic diagram of another preferred structure for expanding the DRS to include a plurality of CRS ports.

As shown in FIG. 6, the extended CRS port can directly reuse the existing CRS port 1 to CRS port 3 mapping structure in a subframe, and occupies only the second subframe occupied by the DRS Lt; / RTI &gt;

Figure 7 illustrates a schematic diagram of another preferred architecture for expanding the DRS to include a plurality of CRS ports.

As shown in FIG. 7, it is assumed that the extended CRS port can also be obtained by shifting the existing CRS port in the time domain, and can occupy only the second subframe occupied by the DRS. In FIG. 7, it is assumed that four CRS ports are required, where the CRS port a / b / c is obtained by shifting the existing CRS port and corresponds to a measurement of each of the CRS ports 1/2/3.

In another aspect, the DRS may be extended to include a plurality of CRI-RS ports to support the CSI-RS measurement based on multiple CRS ports. Here, after the extension, the number of CSI-RS ports included by the DRS is equal to the number of CSI-RS ports for the CSI measurement. In particular, when two CSI-RS ports are required, the CSI-RS port 15 and the CSI-RS port 16 can be directly supported in the two mapped REs of the CSI-RS configured by the DRS signal. Alternatively, when four or eight CSI-RS ports are required, four or eight REs are allocated in the subframe in which the CSI-RS is configured by the DRS signal, and four or eight REs, It is used to convey CSI-RS resources of CSI-RS ports. The plurality of extended CSI-RS ports may also exist in one subframe of the DRS. Alternatively, the plurality of extended CSI-RS ports may be distributed to some or all of the sub-frames of the DRS.

Alternatively, in order to support the CSI measurement based on a plurality of CSI-RS ports, a plurality of CSI-RS ports for the CSI measurement may be separately configured. In the subframe of the DRS consisting of the reference signal for the CSI measurement, both the DRS and the configured reference signal for the CSI measurement are transmitted. The higher layer signaling may be used to configure the number of ports of CSI-RS resources for CSI measurement, the offset of the subframes occupied by the DRS, and the occupied RE. Also, the RE of the plurality of CSI-RS ports constituted by the signal may be limited to be different from the RE of the CSI-RS ports constituted by the existing DRS signal. Alternatively, no limit can be made to the RE, and there can be no limitations on the base station implementation.

The second way of extending the DRS structure is to extend only the CRS port or to extend only the CSI-RS port or to extend the reference signal for CSI measurements of both types . In this manner, the UE measures the CSI using the extended CRS ports and / or the extended NZP CSI-RS ports. In particular, signals of both types can be used to measure the CSI. Alternatively, only one type of signal is used to measure the CSI. Alternatively, the CSI may be measured according to the Transmission Mode (TM) of the UE. As an example, for TM 1 through TM 8, the CSI may be measured based on the CRS port. For TM 9, the channel component of the CSI can be measured based on the NZP CSI-RS port, and the interference component of the CSI can be measured based on the extended CSI port. For TM 10, the channel component of the CSI can be measured based on this NZP CSI-RS port and the interference component of the CSI is measured based on the RE where the current cell power is zero in the DRS sub-frames . For example, the RE with the current cell power of 0 may mean all of the REs where the current cell power is zero in the DRS subframes. Alternatively, the RE may be an interference measurement resource configured by re-using the configuration method of the ZP CSI-RS, for example, by higher layer signaling in one of the subframes occupied by the DRS. Alternatively, the subframe in which the ZP CSI-RS exists may be a subframe including the NZP CSI-RS among the subframes occupied by the DRS.

In the third method, the position of the reference signal for the CSI measurement is stably fixed using the upper layer signaling. When the subframe in which the reference signal exists is overlapped with the subframe in the DRS, both the DRS and the reference signal for the CRS measurement are transmitted in this subframe of the DRS. For the CSI-RS, when the CSI-RS overlaps with the sub-frame of the DRS, the CSI-RS can be directly transmitted in this subframe of the DRS. For the CRS, the CRS may be transmitted discontinuously when used for CSI measurements. In particular, the higher layer signaling may be used to configure the cycle, offset, and duration of the CRS for the CSI measurement. That is, in one cycle, the CRS for the CSI measurement is transmitted from the indicated offset. In the time period of the CRS, the CRS may be transmitted in one or more subframes. Alternatively, the CRS may be defined to be transmitted in a shorter period, e.g., a time slot. In this manner, if a CRS for the CSI measurement is overlapped with one or more subframes of the DRS, and the CRS includes a plurality of CRS ports, And may be transmitted directly in more subframes.

In the second embodiment

In the second embodiment, how to provide feedback based on other characteristics of the CSI during CSI measurements based on different types of downlink signals is described.

In accordance with the above description of the present application, in the unlicensed band carrier, the CSI reported by the UE may be derived from several other types of signals. In one aspect, the CSI measurement at the time when the base station transmits downlink data is most accurate. In another aspect, the interference of other devices received by the UE relatively more accurately reflects the interference received by the UE when the UE receives data. Here, since the transmission power for transmitting the downlink data is generally large, all other devices in a large range close to the base station can not transmit signals, and therefore the interference received by the UE is relatively low.

8 shows a schematic diagram of the interference distribution of the UE when the base station transmits downlink signals in different areas.

As shown at 802 in FIG. 8, when the base station 800 transmits downlink signals, all other base stations A, B, C around the base station 800 can not transmit signals , So the UE will only receive interference from the base station D However, even if the channel component of the CSI measurement is still accurate for the CSI measured when the base station transmits a reference signal specific to the DRS or CSI measurement, since the transmission power of the base station is generally low, Only devices within a small range can not transmit signals, and therefore the level of interference present from other devices and received by the UE is higher than the level of interference at the time the base station transmits downlink data. As shown in FIG. 8, when the base station 800 transmits a DRS, only the base station 800's attention can not transmit signals, and thus the UE transmits the signals to the base stations B, C, / RTI &gt; and / or &lt; / RTI &gt; In this way, when configuring the CSI feedback of the UE, other characteristics of CSI that are measured based on different types of signals need to be considered.

The first is to construct a CSI that feeds back only one type of signal for one CSI process. That is, one CSI process feeds back only the CSI measured at the time when the base station occupies the channel and transmits the downlink data, or one CSI process measures based on the reference signal specific to the DRS or the CSI measurement Only CSI is fed back. Here, with respect to the above-described method of configuring the window of the CSI measurement, the UE feeds back a valid CSI only when a signal of the type corresponding to this CSI process exists in this window. Otherwise, the UE may indicate that the CSI is not valid. For example, the UE reports a CQI index 0 (OOR).

On the other hand, the second method is still to allow one CSI process to measure and feed back CSI information based on the two types of signals as described above. It will be appreciated that the two types of signals are classified according to the level of interference with the UE. Here, since the interference levels in the subframes in which the signals of the two types exist in general are different, the averaging operation is unsuitable for interference in the subframes in which the signals of the two types exist. At this time, it can be defined that the measurement of the interference component of the CSI measurement can take an average only for the sub-frames of the same type of signals. Alternatively, it can be defined that the interference component of the CSI measurement can only be calculated on the basis of one subframe, i.e. the averaging operation is not performed on the interference. Alternatively, the interference component of the CSI measurement may be defined as a weighted average based on the two types of subframes as described above.

According to the above analysis, the CSI measured based on the reference signal specific to the DRS or the CSI measurement is substantially less. This is because the level of the interference signals received by the UE is very low when the downlink data is substantially transmitted. In this way, the CSI measured based on the reference signal specific to the DRS or the CSI measurement can be compensated to approximate the CSI measured at the time when the downlink data is transmitted.

In some implementations, the compensation may be performed at the UE side. That is, the UE determines an interference level A in a period in which the base station transmits downlink data, determines an interference level B in a period in which the base station transmits a reference signal specific to the DRS or the CSI measurement, , The UE can compensate the measured signal-to-noise ratio according to the interference level A and the interference level B. As an example, the signal-to-noise ratio measured based on the reference signal specific to the DRS or CSI measurement is increased by (B-A) dB, where A and B are assumed to be in dB.

In another implementation, the compensation may be performed at the base station side. In particular, the base station may configure signal transmission assumptions for CSI measurements based on downlink data transmission based CSI measurements and CSI measurements based on a reference signal specific to the CSI measurements. Alternatively, when the CSI is measured based on the DRS or based on a reference signal specific to the CSI measurement, it may be directly instructed to increase the measured power of the channel component by X dB. Alternatively, equivalently, the measured power of the interference component may be reduced by X dB. Here, the value of X is based on the difference between the interference levels in two situations. For other UEs, X is generally different in other areas. The base station may configure the value of X through signaling.

According to the current LTE standard, for the channel measurement based on the CRS, the UE determines the assumption of the signal power during the measurement of the CSI based on the power reference P _A and the offset Δ _offset constituted by the higher level do. That is, TM 2, which is composed of four CRS ports, TM 3, which is composed of four CRS ports, and ρ _A = P _A + Δ _offset + 10log ₁₀ for a situation where the rank indication (RI) (2) dB; Otherwise, for any modulation scheme and any number of layers, ρ _A = P _A + Δ _offset dB.

ρ _A is the ratio of the EPRE of the PDSCH to OFDM symbols not including the power of each RE (RERE) of the CRS to the CRS.

In this manner, in one implementation, is to the method of compensation is made for two Δ _offset, the one of the two Δ _offset is used for the CSI measurement that is based on the downlink data transmission, Δ _offset, expressed as ₁ And the other one is used for the CSI measurement based on the DRS or the reference signal specific to the CSI measurement, and is expressed as DELTA _offset, 2. Δ _{offset, 2} is X dB higher than Δ _{offset, 1} .

Alternatively, in another implementation, the method for compensating is to indicate X. That is, for CSI measurements based on the downlink data transmission, the assumption of the signal power during the CSI measurement is determined based on P _A and Δ _offset , and is expressed as ρ _A = f (P _A , Δ _offset ) Loses. For a CSI measurement based on a reference signal specific to the DRS or the CSI measurement, the assumption of the signal power during the CSI measurement is determined as p _A = f (P _A , Δ _offset ) + X.

According to the current LTE standard, for channel measurement based on the CSI-RS, the UE determines the assumption of the signal power during the CSI measurement based on the power criterion P _C configured by the higher level.

In this way, in one embodiment, the method of compensation is to configure two P _C, wherein one of the two P _C is used for the CSI measurement that is based on the downlink data transmission, expressed as P _C1, And the other one is used for CSI measurement based on the DRS or the reference signal specific to the CSI measurement, and is expressed as P _C2 . P _C2 is X dB higher than P _C1 .

Alternatively, in another implementation, the method for compensating is to indicate X. That is, for CSI measurements based on the downlink data transmission, the assumption of the signal power during the CSI measurement is determined based on P _C. For a CSI measurement based on the DRS or the reference signal specific to the CSI measurement, the assumption of the signal power during the CSI measurement is determined based on P _C + X.

Third Embodiment

In the third embodiment, how CSI is reported when there is a conflict between CSI feedback resources is described.

In some situations, the same resource may be occupied to feed back some CSIs. In one example, in this area, a periodic CSI (P-CSI) of a plurality of carrier components (CCs) and / or a P-CSI of a plurality of CSI processes and / In the current LTE system, for CSI feedback in the PUCCH, if there is a collision between PUCCH resources, a higher (higher) PUCCH may be configured. The order of priorities from a priority to a low priority is a CSI report type> CSI process ID> cell ID> CSI subframe aggregation index, where the CSI report type is a pre-coded matrix indicator / channel quality indicator Is used to distinguish more important CSI such as RI from normal CSI such as Pre-coded Matrix Indication / Channel Quality Indication (PMI / CQI) information.

According to the above description of the present application, in a carrier in the unlicensed band, the CSI reported by the UE can be derived from several different types of signals, and the validity of the different types of signals is different. In particular, the CSI measured at the time when the base station transmits downlink data is the most accurate and therefore most efficient. This is because the interference of other devices received by the UE reflects the interference received by the UE relatively accurately when the UE receives data. The CSI measured at the time when the base station transmits the reference signal specific to the DRS or the CSI measurement has a relatively low accuracy and thus has a relatively low efficiency. This is because the transmit power is generally relatively low and even though the measurements in the channel component are accurate, only the devices within a small range around the base station can not transmit signals and thus the level of interference that the UE receives from other devices Is higher than the level of interference at the time when the base station transmits downlink data. Consequently, since the base station does not occupy the channel for a long time, the pure interference level indicator reported by the UE only provides a reference for the scheduling of the base station, and therefore has the lowest efficiency.

In this way, in one implementation, if it occurs to occupy the same resources and feed back more CSI information of the unlicensed band, the efficiency corresponding to the CSI measurements of the plurality of types as described above may be the efficiency of processing the CSI report Can be used as a high priority, i.e., CSI validity> CSI report type> CSI process ID> cell ID> CSI subframe set index. In this way, the CSI measurement at the time when the base station transmits downlink data has the highest priority, and the CSI measured when the base station transmits a reference signal specific to the DRS or the CSI measurement, , And the pure interference level indicator reported by the UE has the lowest priority. The pure interference level indicator may be considered as a definition that it is not suitable for the CSI reporting type. Alternatively, the pure interference level indicator may be considered to correspond to one CSI report type, and may be considered to be equivalent to PMI / CQI, for example. In this way, it can be ensured that the CSI reported by the UE should be the CSI with the highest validity.

Alternatively, in another implementation, the priority of such validity may be set to be lower than the CSI reporting type, but may be set higher than other parameters, such as CSI reporting type> CSI validity> CSI process ID &Gt; cell ID > CSI subframe set index. In this way, it is ensured that the priority of the more important CSI information such as RI is higher than the normal PMI / CQI information. The pure interference level indicator may be considered as a definition that it is not suitable for the CSI reporting type. Alternatively, the pure interference level indicator may be considered to correspond to one CSI report type, and may be considered to be equivalent to PMI / CQI, for example.

When the CSI of the carrier of the unlicensed band and the CSI of the applied band are fed back by occupying the same resources, the order of priority of the CSI of the applied band and a plurality of types of CSI of the non- You need to define them.

In one implementation, when the priority is determined, the band types can be classified, i.e. classified into an authorized band and an unlicensed band. The band type may have the highest priority; Or the priority of the type of the band is higher than the priority of the CSI validity but less than the priority of the CSI reporting type; Or the priority of the band type is higher than the priority of the CSI reporting type but lower than the priority of the CSI reporting type; Or the priority of the band type is lower than the priority of the CSI validity, but higher than the priority of other parameters; Or the priority of the band type is higher than the priority of the cell ID but lower than the priority of the CSI process ID; Or the priority of the band type is higher than the priority of the CSI subframe set index, but lower than the priority of the cell ID.

Alternatively, in another implementation, the validity of the CSI of the licensed band may be specified such that the validity of the CSI of the unlicensed band can be aligned with the validity. Here, the reference signal for CSI measurement of the applied band can be periodically transmitted, and the CSI can always be reported in time. Therefore, the validity of the CSI of the applied band can be defined to be higher than the validity of the CSI of the unlicensed band. Alternatively, when considering the competitive characteristics of channel occupancy of the unlicensed band, the opportunity to measure CSI based on the downlink data transmission and / or the reference signal specific to the DRS or CSI measurement is limited. Thus, the validity of the CSI of the applied band may be defined to be lower than the validity of the CSI measured based on the downlink data transmission and / or the reference signal specific to the DRS or CSI measurement. Alternatively, the validity of the CSI of the authorized band may be lower than the validity of the CSI measured based on the downlink data transmission, but higher than the validity of the CSI measured based on the reference signal specific to the DRS or the CSI measurement .

For P-CSI, the PUCCH resources of the P-CSI of a plurality of applied-band cells and unlicensed band-cells may be configured in the same or partially identical subframes as a whole, and then the UE determines which CSI The feedback is determined using the priority classification as described above. For example, the CSI of the unlicensed band may be configured to have a higher priority than that of the CSI of the applied band, and the UE may be configured to transmit the CSI Is configured to be a small value. That is, the UE can only report the CSI based on the downlink data, the DRS, or the reference signal specific to the CSI measurement within a small period from the base station occupying the channel. The UE preferentially reports the CSI because the priority of the CSI is higher than the priority of the CSI of the granted band. However, at the timing position of the different feedback P-CSI, the unlicensed band can only feed back pure interference indicator. According to the above-mentioned priority order, the UE feeds back the P-CSI of the granted band. In this way, feedback of the different types of CSIs of different bands in one PUCCH resource is achieved according to importance, thus improving resource utilization.

Figure 9 shows a preferred schematic diagram for feeding back P-CSI based on priority.

9, for the P-CSI feedback in the uplink sub-frame n without losing generality, in the sub-frame n-4 and sub-frame n-5, only the downlink signals measure the CSI That is, the size of the window is two. The priority of the CSI measured by the UE based on the DRS transmission 901 is higher than the priority of the CSI of the granted band and thus the UE feeds back the CSI of the unlicensed band from the PUCCH resource 911. Similarly, the UE measures the CSI based on the downlink data transmission 902 and the DRS 903 and feeds back the CSI of the unlicensed band from the PUCCH resource 914 and the PUCCH resource 915. However, in other PUCCH resources, since the UE can only be fed back in the unlicensed band where the priority is lower than the priority of the CSI of the granted band, the UE transmits PUCCH resources 910, 912, 913, 916, 917 feedback the CSI of the applied band. In this manner, the UE can report the CSI of the unlicensed band as long as the latest good information exists in the unlicensed band, and report the CSI of the granted band at another time.

Similarly, such a method of processing the P-CSI can be extended to aperiodic CSI (A-CSI). When constructing the A-CSI with higher layer signaling, it is possible to divide a plurality of applied band cells, unlicensed band cells and / or CSI processes into only one CSI that needs to be fed back. The UE may still select the CSI information that needs to be fed back using a priority strategy as described above.

In the above-described method of feeding back P-CSI and A-CSI, the finally selected CSI information is based on the validity of CSI measured in the unlicensed band, that is, in the unlicensed band, Based on whether or not downlink data has been transmitted. However, the event that the base station occupies the channel and transmits the downlink data may be obtained using the blind detection of the UE, or may be a Downlink Control Indication (DCI), e.g., It is indicated by the DCI format in the Common Search Space (CSS). These methods are not very reliable and may allow the base station and the UE to differently understand whether there is CSI being measured based on the downlink data transmission. In order to prevent the UE from colliding with the CSI, in some embodiments, the indicator information of the CSI may be conveyed in the CSI report reporting the CSI. For example, the UE may report the cell ID, the CSI process ID, the CSI validity type corresponding to the feedback CSI, and the like.

Fourth Embodiment

In the fourth embodiment, how to adjust the CSI feedback according to the change of the signal type for the CSI measurement is explained.

According to the current LTE standard, CSI information of up to 11 bits can be fed back in the PUCCH every time. In this manner, for the subband CSI, the UE can not feed back the CSI information of each subband in the entire bandwidth at a time, but divides the entire bandwidth into several bandwidth parts (BPs) , So that only one CP's subband PMI / COI can be fed back at a time. Also, the cycle in which the UE feeds back the RI is relatively long. That is, in one cycle of feedback of the RI, there may be several opportunities to feedback the PMI / CQI of the BP.

According to the above description of the present application, in the unlicensed band carrier, the CSI reported by the UE may be derived from several other types of signals. In particular, the CSI measured at the time when the base station transmits downlink data is the most accurate. The CSI measured at the time when the base station transmits the reference signal specific to the DRS or the CSI measurement has a relatively low accuracy. Since the base station is not occupying the channel for a long time, the pure interference level indicator reported by the UE has the lowest validity. Due to the randomness of the base station occupying the channel, the time of occurrence of the signals of the several possible types is not determined. In particular, after the RI is reported based on a single type of signal, a new type of signal may be generated before reporting of the PMI / CQI of all BPs is completed. Therefore, it is necessary to define how the UE processes CSI measurements and feedback under these circumstances.

Figure 10 is a diagram illustrating situations that may occur when CSI is fed back due to CSI being measured based on different types of signals.

As shown in FIG. 10, it is assumed that the system bandwidth is divided into five BPs. After the UE measures and reports the RI 1011 and the subband CSIs 1012, 1013, and 1014 of three BPs based on the DRS 1011, 1002 can operate as a criterion of CSI measurement for processing the CSI report of two BPs 1015, 1016. However, the characteristics of the DRS 1001 and the downlink data transmission 1002 are different.

In the first method, it does not matter which new signal type is useful for measuring the CSI, and the PMI / CQI report of all BPs in the whole bandwidth is always according to the signal type of the most recently reported RI, Lt; / RTI &gt; However, the new RI report needs to be measured according to the new signal type.

11 shows a preferred schematic diagram of CSI feeding back RI and CSI feeding back each BP according to the first method.

11, the feedback RI 1111 is obtained in accordance with the DRS 1101 and the next five BPs 1112 to 1116, and each of the five BPs 1112 to 1116 includes a DRS , I.e., the DRS 1101 in FIG. Next, the fed back RI 1117 is obtained according to the downlink data transmission 1102 and the next five BPs 1118 to 1122, and each of the five BPs 1118 to 1122 receives downlink data transmission , I.e., downlink data transmission 1102 in FIG.

In the second method, due to the occurrence of new signal types useful for measuring CSI, the PMI / CQI and RI of the next BP are measured based on the new signal type. Here, it is assumed that, before reporting the new RI, the RI is the same as the most recently reported RI, even though the PM's PMI / CQI of the BP is measured based on the new signal type.

12 is a diagram showing a preferred schematic diagram of CSI for feedback of RI and each BP according to a second method.

As shown in FIG. 12, after the feedback RI 1211 and the subbands CSIs 1212-1214 of the three BPs are acquired according to the DRS 1201, the downlink data transmission 1202 is transmitted to the CSI It becomes possible to operate as a reference for measurement. At this time, although the UE still operates according to the RI fed back at 1211, the subband CSI of the two BPs 1215 and 1216 is calculated based on the downlink data transmission 1202. Next, the UE may obtain the RI 1217 and the subband CSI 1218 of the BP based on the downlink data transmission 1202. Then, for the next four BPs 1219 through 1222, the RI calculated according to the downlink data transmission 1202 is used, but the subband CSI is calculated based on the DRS 1203.

In the third method, the PMI / CQI and RI of the next BP are measured based on the new signal type if the priority of the new signal type useful for measuring CSI is higher than the priority of the previous signal type. Here, before reporting the new RI, it is assumed that the RI is the same as the most recently reported RI, even though the PM's PMI / CQI of the BP is being measured based on the new signal type. If the priority of the new signal type useful for measuring CSI is lower than the priority of the previous signal type, then the previous signal type is still used to feed back the CSI.

Figure 13 shows a preferred schematic diagram of each CSI and CSI that feeds back the RI according to the third method.

13, after the feedback RI 1311 and the subbands CSIs 1312-1314 of the three BPs are obtained according to the DRS 1301, the downlink data transmission 1302 is performed by CSI measurement Lt; / RTI &gt; In this case, since the priority of the CSI based on the downlink data transmission 1302 is higher than that of the CSI based on the DRS 1301, the two BPs 1315 and 1316 are fed back The processing method is the same as the second method. That is, the UE still operates according to the fed back RI at 1311, but the subband CSI of the two BPs 1315, 1316 is calculated based on the downlink data transmission 1302. In the following, the UE may obtain the RI 1317 and the subband CSI 1318 of the BP based on the downlink data transmission 1302. Since the priority of the CSI based on the DRS 1303 is lower than that of the CSI based on the downlink data transmission 1302 for the next four BPs 1319 to 1322, In the third method, the subband CSI is still calculated based on the downlink data transmission 1302.

In a fourth method, when the priority of the new signal type useful for measuring CSI is higher than the priority of the previous signal type, the RI from the PUCCH resource satisfying the process delay, Is reported first, and then the PMI / CQI of each BP is reported. When using this method, the time to report the RI is random. Therefore, when P-CSI is fed back to the PUCCH, it is necessary to indicate the CSI type currently reported by the UE, i.e., the RI-related information or the PMI / CQI of the BP.

14 is a diagram illustrating a preferred flow chart of a method for receiving a CSI according to an embodiment of the present invention. As shown in FIG. 14, the method includes the step 1401 of transmitting a plurality of types of downlink signals for CSI measurements by the base station.

The signals transmitted by the base station and useful for CSI measurement are a reference signal for CSI measurements transmitted within a time period in which the base station transmits downlink data; DRS; And other types including at least one of the reference signals specific to the CSI measurement. Since specific details have been described above, the details thereof will be omitted.

In step 1402, the base station receives a CSI that is measured based on the plurality of types of downlink signals and fed back by the user equipment (UE).

In some embodiments, receiving a CSI that is fed back by the UE and that is measured based on multiple types of downlink signals includes: receiving only CSIs that are measured based on one type of downlink signal in one CSI process do or; Or receiving a CSI that is measured based on multiple types of downlink signals in one CSI process.

Upon receiving a CSI that is measured based on multiple types of downlink signals in one CSI process, the base station may perform the following operations: interference levels corresponding to other types of downlink signals Constructing the signal power assumptions of the CSI measurements based on each of the other types of downlink signals; Or to instruct the UE to increase the power of a channel component obtained from a CSI measurement corresponding to a high interference level by a predetermined value (e.g., X dB), or from a CSI measurement corresponding to a high interference level And decreasing the power of the interference component obtained by the predetermined value (X dB).

Figure 15 is a simplified block diagram of an entity 1500 that is adapted to implement many preferred embodiments of the present application. The entity 1500 may comprise a network-side device such as a base station. The entity 1500 may also be configured as a user-side device, such as a user terminal.

15, the entity 1500 includes a processor 1501, a memory 1502 coupled to the processor 1501, and a memory 1502 coupled to the processor 1501 and adapted to receive radio signals of a suitable radio frequency frequency (RF) transmitter and receiver 1504. The storage unit 1502 stores the program 1503. The transmitter / receiver 1504 is suitable for two-way wireless communication. It should be noted that the transmitter / receiver 1504 has at least one antenna for assisting communication. Indeed, the base station or UE may have multiple antennas. The entity 1500 may be coupled to one or more external networks or systems, such as internetworks, via a data path.

The program 1503 may include program instructions. When such program instructions are executed by the coprocessor 1501, the program instructions cause the entity 1500 to operate in accordance with the preferred embodiments of the present invention.

Embodiments of the present invention may be implemented by computer software, or hardware, or a combination of software and hardware, that may be executed by the processor 1501 of the entity 1500.

The storage unit 1502 may be any suitable type of memories suitable for local technical environments, and may include storage devices and systems based on semiconductors, magnetic storage devices and systems, optical storage devices and systems, And may be implemented using any suitable data storage techniques such as, for example, a stored storage and a moving storage, but these are merely examples without limitation. Although only one memory is shown in the entity 1500, a plurality of physically separate memory cells may be present in the entity 1500. The processor 1501 may be any suitable type of processor suitable for the local technical environment and may include one or more of the following items: a general purpose computer, a dedicated computer, But are not limited to, microprocessors, microprocessors, digital signal processors (DSPs), and processors based on the architecture of a multi-core processor.

If the entity 1500 is configured as a user-side device, i.e., the entity 1500 is a user terminal, in some embodiments, the receiver of the transmitter / receiver 1504 may include a plurality of types of downlink signals . The processor 1501 is configured to measure channel state information (CSI) in the plurality of types of downlink signals. The transmitter of the transmitter / receiver 1504 is configured to feed back measured CSI based on the plurality of types of downlink signals to the base station.

In some embodiments, when the entity 1500 is configured as a network-side device, that is, when the entity 1500 is a base station, the transmitter of the transmitter / receiver 1504 is configured for CSI measurements under the control of the processor And is configured to transmit a plurality of types of downlink signals. The receiver of the transmitter / receiver 1504 is configured to receive CSI fed back by a User Equipment (UE) and fed back based on a plurality of types of downlink signals.

It is to be understood that the units included in the entity 1500 are configured to implement the preferred embodiments described herein. Accordingly, the above-described operations and features described with reference to FIGS. 3 to 14 are also suitable for the entity 1500 and its units, and a detailed description thereof will be omitted here.

In another aspect, the present application provides a computer readable storage medium, wherein the computer readable storage medium resides in a computer readable storage medium contained in the base station or in a communication device or device of the above embodiments Can be a non-assembled computer readable storage medium. The computer readable storage medium is stored in one or more programs and the one or more programs are used by one or more processors to execute a cellular access method as described in this application.

The foregoing description is merely illustrative of the preferred embodiments of the present application and of the technical principles in use. It should be understood by those skilled in the art that the scope of the invention with respect to this application is not limited to the technical solutions provided by the specific combinations of the technical features described above, Other technical solutions, such as those described above, that are formed by any combination of the same technical features or their equivalent features, such as those described in (but not limited to) It should be understood that the branches must include technical features and technological solutions formed by interchanging with each other.

Various embodiments of the present invention may be embodied as computer readable code in a computer readable recording medium in particular aspects. The computer readable recording medium is any data storage device capable of storing data that can be read by a computer system. Examples of computer readable recording media include read only memory (ROM), random access memory (RAM), compact disk-read only memory (CD-ROMs), magnetic tapes, floppy disks, optical data storage devices, and carrier waves (such as data transmission over the Internet) . The computer readable recording medium may also be distributed over networked computer systems, and thus the computer readable codes are stored and executed in a distributed manner. Also, functional programs, code, and code segments for accomplishing various embodiments of the present invention may be readily interpreted by programmers skilled in the art to which the invention applies.

It will also be appreciated that the apparatus and method according to various embodiments of the present invention may be implemented in hardware, software, or a combination of hardware and software. Such software may be, for example, a volatile or nonvolatile storage device such as a storage device such as ROM, whether removable or rewritable, or a memory such as, for example, a RAM, memory chip, For example, a storage medium readable by a machine (e.g., a computer), such as a compact disk (CD), a DVD, a magnetic disk, or a magnetic tape. A method according to various embodiments of the present invention may be implemented by a computer or a mobile terminal including a controller and a memory, which memory stores programs or programs including instructions embodying embodiments of the present invention It will be appreciated that this is an example of a suitable machine readable storage medium.

Accordingly, the present invention includes a program including code for implementing the apparatus or method described in the claims, and a storage medium readable by a machine (such as a computer) for storing such a program. In addition, such a program may be electronically transferred through any medium, such as a communication signal carried over a wired or wireless connection, and the present invention appropriately includes equivalents thereof

Also, an apparatus according to various embodiments of the present invention may receive and store a program from a program providing apparatus connected by wire or wirelessly. The program providing apparatus includes a memory for storing a program including instructions for causing the program processing apparatus to perform a predetermined content protection method, information necessary for the content protection method, and the like, and a program for executing a wired or wireless communication with the graphics processing apparatus A communication unit, and a control unit for requesting the graphic processing apparatus or automatically transmitting the program to the transmission / reception apparatus.

The embodiments of the present invention disclosed in the present specification and drawings are merely illustrative of the technical contents of the present invention and are intended to illustrate specific embodiments in order to facilitate understanding of the present invention and are not intended to limit the scope of the present invention. It should also be understood that the embodiments of the present invention described above are merely illustrative, and that those skilled in the art will be able to make various modifications and equivalent embodiments. Accordingly, the true scope of the present invention should be determined by the following claims.

Claims (21)

A method for measuring and reporting channel state information (CSI)
The UE measuring CSI in a plurality of downlink signals;
And feedback the measured CSI based on the plurality of types of downlink signals by the UE,
Wherein the CSI is measured based on at least one type of downlink signals, the at least one type of downlink signals comprising:
A reference signal for CSI measurement transmitted by the base station within a time period in which the base station transmits downlink data, a search reference signal (DRS) transmitted by the base station, and a CSI measurement, Wherein the reference signal comprises at least one of a reference signal to be transmitted and a reference signal to be transmitted. The method of claim 1, further comprising: indicating to the base station that the CSI is not valid if the UE does not receive any signal transmitted by the base station within a predetermined time period; or
Further comprising the step of the UE indicating the current channel interference level to the base station. 3. The method of claim 2, wherein the step of the UE indicating a current channel interference level to the base station comprises:
And feeding back a pure interference level indicator to the base station if the UE does not receive a signal transmitted by the base station within a window configured by the base station to measure the CSI The method comprising the steps of: 4. The method of claim 3, wherein the step of measuring the CSI comprises:
Directly using the DRS as a reference signal for the CSI measurement;
Extending the DRS for the CSI measurement and using a plurality of reference signal ports included in the DRS;
And performing the CSI measurement based on a reference signal for CSI measurement configured in the DRS through a high layer signaling. &Lt; RTI ID = 0.0 &gt; 8. &lt; / RTI &gt; 5. The method of claim 4, wherein using the plurality of reference signal ports included in the DRS comprises:
Using a plurality of CRS ports extended and included in all or a part of sub-frames of DRS for CSI measurement;
And using a plurality of CSI-RS ports extended and included in all or a part of sub-frames of the DRS for the CSI measurement. 5. The method of claim 4, wherein the higher layer signaling comprises a cycle, an offset and a duration of a cell common reference signal for the CSI measurement. The method of claim 1, wherein the feedback of the measured CSI based on the plurality of types of downlink signals by the UE comprises:
And feeding back the CSI according to a predetermined priority when occupying the same resource to feed a plurality of CSIs of an unlicensed band occurs,
Wherein the predetermined priority is:
The validity of the CSI is set to have the highest priority;
Wherein the CSI report type has the highest priority and the priority of the validity of the CSI is determined to be lower than the priority of the CSI report type. The method of claim 1, wherein the feedback of the measured CSI based on the plurality of types of downlink signals by the UE comprises:
Determining the priority according to a type of a corresponding band when occupying the same resource to feed back the CSI of the unlicensed band and the CSI of the licensed band; or
And arranging the CSI of the unlicensed band and the CSI of the applied band according to the validity,
Wherein the CSI of the applied band has a predetermined validity. 9. The method of claim 8, wherein the predetermined validity of the CSI of the applied band is:
Or higher than the CSI of the unlicensed band;
Or less than the CSI of the unlicensed band;
Is lower than the CSI of the unlicensed band but higher than the CSI measured based on the reference signal specific to the DRS and CSI measurements. 8. The method of claim 7, wherein the feedback of the CSI measured by the UE based on the plurality of types of downlink signals comprises:
Further comprising the step of the UE reporting the identification information of the feedback CSI,
Wherein the identification information comprises at least one of a corresponding cell identifier, a CSI process identifier, and a CSI validity type. The method of claim 1, wherein the feedback of the CSI measured by the UE based on the plurality of types of downlink signals comprises:
Feeding back CSI measured based on one type of downlink signal in one CSI process; or
And feeding back the CSI measured based on the plurality of types of downlink signals in one CSI process. 12. The method of claim 11, wherein, in the one CSI process, when the CSI is measured based on the plurality of types of downlink signals, the interference component of the CSI measurement is:
Or by performing an averaging operation on the measurement of the interference component only in sub-frames of signals of the same type;
Obtained through measurement of the interference component without an averaging operation;
And obtaining an average weighted for the measurement of the interference component based on the interference levels corresponding to the other types of downlink signals. 12. The method of claim 11, wherein, when feeding back CSI measured based on the plurality of types of downlink signals in one CSI process, depending on the interference levels corresponding to the different types of downlink signals, Further comprising performing a compensating operation on the CSI measured based on the downlink signals. &Lt; Desc / Clms Page number 19 &gt; 14. The method of claim 13, wherein the compensating operation comprises:
Wherein the UE determines an interference level A in a period in which the base station transmits downlink data and determines an interference level B in a period in which the base station transmits a reference signal specific to the DRS or the CSI measurement, Compensating for a signal-to-noise ratio obtained from a CSI measurement of the UE according to an interference level A and an interference level B;
The power of the channel component obtained from the CSI measurement corresponding to the high interference level is increased by a predetermined value or the interference component obtained from the CSI measurement corresponding to the high interference level is increased according to the instructions of the base station, And decreasing the power of the CSI by the predetermined value. &Lt; Desc / Clms Page number 20 &gt; The method of claim 1, wherein the feedback of the CSI measured by the UE based on the plurality of types of downlink signals comprises:
Coded matrix indicator / channel of all bandwidth parts (BPs) in the entire bandwidth based on the signal of the same type according to the signal type based on the most recently reported Rank Indication (RI) A method of feeding back a quality indicator (Pre-coded Matrix Indication / Channel Quality Indication: PMI / CQI);
A method of feeding back the PMI / CQI of each BP based on the downlink signal of the channel most recently occupied by the base station, wherein RI is assumed to be equal to the most recently reported RI;
A method of feeding back the PMI / CQI of each BP based on the downlink signal of the channel most recently occupied by the base station when the priority of the new signal type useful for measuring the CSI is higher than the previous signal type, Where RI is assumed to be the same as the most recently reported RI;
CQI of each BP from a physical uplink control channel (PUCCH) resource satisfying a process delay when a priority of a new signal type useful for measuring the CSI is higher than a previous signal type. And feeding back the RI and the PMI / CQI of subbands of each BP according to any one of the methods of feeding back RI measured based on the new signal type. . A method for receiving channel state information (CSI)
The base station transmitting a plurality of types of downlink signals for CSI measurements;
And receiving the CSI, which is fed back by the user terminal (UE) and measured based on the plurality of types of downlink signals,
The plurality of types of downlink signals include:
A reference signal for CSI measurement to be transmitted within a time period in which the base station transmits downlink data, a search reference signal (DRS), and a reference signal specific to the CSI measurement. How to receive. 17. The method of claim 16, wherein transmitting the downlink signals comprises:
Directly using the DRS as a reference signal for the CSI measurement;
Expanding the DRS to include a plurality of reference signal ports for CSI measurement;
And constructing a reference signal for the CSI measurement in the DRS through higher layer signaling. 17. The method of claim 16,
Receiving a CSI fed back by the UE and measured based on the plurality of types of downlink signals comprises:
Receiving a CSI measured based on one type of downlink signal in one CSI process; or
And receiving a CSI measured based on the plurality of types of downlink signals in one CSI process. 19. The method of claim 18,
When receiving the CSI measured based on the plurality of types of downlink signals in the one CSI process,
Configuring the signal power estimates of the CSI measurements based on each of the other types of downlink signals, in accordance with interference levels corresponding to different types of downlink signals; or
Instructing the UE to increase the power of a channel component obtained from a CSI measurement corresponding to the high interference level by a predetermined value or by instructing the UE to increase the power of an interference component obtained from a CSI measurement corresponding to the high interference level And decreasing the CSI by a predetermined value. A user terminal comprising a receiver, a transmitter and a processor,
The receiver being configured to receive a plurality of types of downlink signals from a base station;
Wherein the processor is configured to measure channel state information (CSI) in the plurality of types of downlink signals;
Wherein the transmitter is configured to feed CSI measured to the base station based on the plurality of types of downlink signals,
Wherein the CSI is measured based on at least one type of downlink signals, the at least one type of downlink signals comprising:
A reference signal for CSI measurement transmitted by the base station within a time period in which the base station transmits downlink data, a search reference signal (DRS) transmitted by the base station, and a CSI measurement, And a reference signal to be transmitted. A base station comprising a receiver, a transmitter and a processor,
Wherein the transmitter is configured to transmit a plurality of types of downlink signals for CSI measurements under the control of the processor;
Wherein the receiver is adapted to receive the CSI fed back by a user terminal (UE) and measured based on the plurality of types of downlink signals,
The plurality of types of downlink signals include:
Wherein the base station comprises at least one of a reference signal for CSI measurement, a search reference signal (DRS), and a reference signal specific to the CSI measurement transmitted within a time period in which the base station transmits downlink data.

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