Patent Description:
A channel state information-reference signal (Channel State Information-Reference Signal, CSI-RS) is used as a reference signal for channel state information measurement in a 3rd Generation Partnership Project (the 3rd Generation Partnership Project, 3GPP) Long Term Evolution (Long Term Evolution, LTE) system. To further improve spectrum efficiency, more antenna configurations, especially antenna configurations of more than eight antenna ports based on an active antenna system (Active Antenna Systems, AAS), are introduced in a current LTE R13 standard. For example, there may be <NUM>, <NUM>, or <NUM> antenna ports.

In the prior art, both a CSI reporting type A and a CSI reporting type B are supported. CSI measurement in the CSI reporting type A is based on a non-beamforming CSI-RS resource, and CSI measurement in the CSI reporting type B is based on a beamforming CSI-RS resource. A CSI process corresponding to the non-beamforming CSI-RS resource is a CSI process of the type A, and a CSI process corresponding to the beamforming CSI-RS resource is a CSI process of the type B. As a quantity of antenna ports increases, reference signal resource overheads in the CSI process of the type A accordingly increase.

<CIT> discloses a method and an apparatus for transmitting and receiving CSI for use in a wireless communication system using a plurality of antennas. The CSI transmission method of a terminal includes receiving a first CSI-RS and a second CSI-RS, transmitting a CSI indicator indicating one of the first and second CSI-RS corresponding to CSI to be transmitted, and transmitting the CSI generated based on the CSI indicator, until transmission of a new CSI indicator. <CIT> discloses user equipment and a method for a transceiver operable to communicate with the at least one base station. The processing circuitry is configured to control the transceiver to receive a first set of CSI-RS according to a first CSI process configuration; receive a second set of CSI-RS according to a second CSI process configuration; transmit a PUCCH comprising a first RI on a RI reporting subframe derived according to the first CSI process configuration. In particular, one or more embodiments described in this document provide configuring a user equipment with horizontal H and vertical V CSI feedback in FD-MIMO systems. In some embodiments, the user equipment can provide a joint CQI with selected V-PMI, H-PMI, V-RI and H-RI. In some embodiments, the joint CQI is derived with a composite precoding matrix constructed by a Kronecker product of two rank-<NUM> precoding matrices, respectively corresponding to the most recently reported H-PMI and V-PMI.

<CIT> discloses a multipoint channel state information reporting method and device.

The present invention provides a channel state information reporting method, and a system comprising a terminal and a base station, as defined in the appended set of claims, to reduce reference signal resource overheads in a CSI process.

A dimension of the first PMI is less than a dimension of the second PMI, and this reflects that a quantity of ports corresponding to a first reference signal resource is less than a quantity of total antenna ports that are to perform transmission, so that resource overheads can be reduced.

The CQI index indicator corresponds to an operational criterion for obtaining the CQI based on the R first PMIs. The terminal reports the CQI index indicator corresponding to the CQI, to notify the base station of the operational criterion for obtaining the CQI.

In a possible design, the R first PMIs are used by the base station to determine a precoding matrix and/or a quantity of ports of a second reference signal resource. To be specific, the base station uses the R first PMIs for beamforming on the second reference signal resource. The first reference signal resource and the second reference signal resource are different types of reference resources. The first reference signal resource is a non-beamforming reference signal resource of a type A, and the second reference signal resource is a beamforming reference signal resource of a type B. Beamforming on the reference signal resource of the type B can be trained by measuring the reference signal resource of the type A, so that accuracy of the beamforming that acts on the reference signal resource of the type B is effectively improved, and system performance based on the reference signal resource of the type B is further improved.

In comparison with the prior art, a PMI with a higher dimension may be obtained by using a PMI with a lower dimension in the solution provided in the present invention, to reduce resource overheads.

To describe the technical solutions in the embodiments of the present invention or in the prior art more clearly, the following briefly describes the accompanying drawings required for describing the embodiments or the prior art.

To make a person skilled in the art understand the technical solutions in the present invention better, the following clearly and completely describes the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Apparently, the described embodiments are merely some rather than all of the embodiments of the present invention.

Details are separately described in the following:.

In the specification, claims, and accompanying drawings of the present invention, the terms "first", "second", "third", "fourth", and so on are intended to distinguish between different objects but do not indicate a particular order. In addition, the terms "include", "have", or any other variant thereof, are intended to cover non-exclusive inclusion. For example, a process, a method, a system, a product, or a device that includes a series of steps or units is not limited to the listed steps or units, but optionally further includes an unlisted step or unit, or optionally further includes another inherent step or unit of the process, the method, the product, or the device.

"Embodiment" mentioned in this specification means that a particular characteristic, structure, or feature described with reference to the embodiments may be included in at least one embodiment of the present invention. The phrase in all locations in this specification does not necessarily mean a same embodiment, or an independent or alternative embodiment exclusive of other embodiments. A person skilled in the art explicitly and implicitly understands that the embodiments described in this specification may be combined with other embodiments.

Some terms in this application are described below, to help a person skilled in the art have a better understanding.

Referring to <FIG> is a schematic diagram of a communications system according to an embodiment of the present invention. The communications system shown in <FIG> includes a terminal <NUM> and a base station <NUM>. The terminal <NUM> performs channel quality measurement on M first reference signal resources in a CSI process, to obtain R first PMIs. Then the terminal <NUM> may obtain a CQI based on the R first PMIs. Finally the terminal <NUM> reports channel state information. The channel state information includes the R first PMIs and N CQIs or the R first PMIs and one CQI. The base station <NUM> reads the channel state information reported by the terminal. The R first PMIs are used by the base station <NUM> to determine P second PMIs according to a first operational criterion, where a dimension of the second PMI is greater than a dimension of the first PMI. It may be learned that, the dimension of the first PMI is less than the dimension of the second PMI, and this reflects that a quantity of ports corresponding to a first reference signal resource is less than a quantity of total antenna ports that are to perform transmission. In other words, although a quantity of antenna ports that are to perform transmission increases, ports for the first reference signal resource designed in this solution need to be only some of the total antenna ports, and therefore resource overheads can be reduced.

The following describes the embodiments of the present invention in detail with reference to accompanying drawings, so that a person skilled in the art has a better understanding.

As shown in <FIG>, a channel state information reporting method provided in an embodiment of the present invention includes the following steps:.

A terminal determines R first precoding matrix indicators PMIs of M first reference signal resources, and determines a channel quality indicator CQI based on the R first PMIs, where M and R are integers greater than or equal to <NUM>.

The terminal reports channel state information, and a base station reads the channel state information reported by the terminal, where the channel state information includes the R first PMIs and N CQIs, or the channel state information includes the R first PMIs and one CQI, the R first PMIs are used by the base station to determine P second PMIs according to a first operational criterion, a dimension of the second PMI is greater than a dimension of the first PMI, and P and N are integers greater than or equal to <NUM>.

It should be noted that the foregoing three values M, R, and P are independent of each other. To be specific, R may be greater than or equal to M, or R may be less than M; P may be greater than or equal to R, or P may be less than R; and so on. A relationship among M, R, and P is not limited in the present invention.

If the channel state information includes the R first PMIs and N CQIs, that the terminal determines the CQI based on the R first PMIs in step S201 is specifically implemented as follows: The terminal determines P second PMIs and N CQIs based on the R first PMIs and the first operational criterion.

Specifically, it is assumed that M reference signal resources in a CSI process are non-beamforming reference signal resources. The terminal performs channel quality measurement on the M reference signal resources, to obtain R first PMIs. For example, the R first PMIs are respectively denoted as an RS1-PMI, an RS2-PMI,. , and an RSR-PMI. Then the terminal obtains P second PMIs based on the R first PMIs by using the first operational criterion. Further the terminal may obtain N CQIs based on the P second PMIs.

Optionally, another manner in which the terminal reports the N CQIs is as follows: The terminal reports a basic CQI and differential items of other N-<NUM> CQIs relative to the basic CQI. For example, it is assumed that to-be-reported N CQIs are a CQI1, a CQI2,. , and a CQIN. The terminal reports the CQI1 in the N CQIs and differential items of other N-<NUM> CQIs relative to the CQI1: a delta_CQI2,. , and a delta_CQIN. Therefore, the N-<NUM> CQIs: the CQI2,. , and the CQIN, are obtained by successively adding the CQI1 to the N-<NUM> CQI differential items: the delta_CQI2,. , and the delta_CQIN. The N-<NUM> CQI differential items are reported, to effectively reduce channel state information reporting overheads.

If the channel state information includes the R first PMIs and the CQI, that the terminal determines the channel quality indicator CQI based on the R first PMIs in step S201 is specifically implemented as follows: The terminal determines one second PMI and one CQI based on the R first PMIs and a second operational criterion.

Optionally, if the terminal reports only one CQI, the channel state information reported in step S202 further needs to include a CQI index indicator corresponding to the CQI reported by the terminal.

Specifically, it is assumed that M reference signal resources in a CSI process are non-beamforming reference signal resources. The terminal performs channel quality measurement on the M reference signal resources, to obtain R first PMIs. For example, the R first PMIs are respectively denoted as an RS1-PMI, an RS2-PMI,. , and an RSR-PMI. Then the terminal may obtain one second PMI based on the M first PMIs by using the second operational criterion. Further the terminal may obtain one CQI based on the second PMI. The second operational criterion is an operational criterion corresponding to a CQI index indicator corresponding to the CQI.

The first operational criterion and the second operational criterion may be at least one of a direct product, a direct sum, and an interpolation. The first operational criterion and the second operational criterion are configured by the base station for the terminal, or the first operational criterion and the second operational criterion are predefined by the base station and the terminal. It should be noted that the first operational criterion and the second operational criterion are not limited to the foregoing three operational criteria.

Optionally, the R first PMIs are used by the base station to determine a precoding matrix and/or a quantity of ports of a second reference signal resource.

The first reference signal resource and the second reference signal resource are different types of reference resources. It is assumed that the first reference signal resource is a non-beamforming reference signal resource of a type A, and the second reference signal resource is a beamforming reference signal resource of a type B. The R first PMIs are used by the base station to determine the precoding matrix and/or the quantity of ports of the second reference signal resource. In other words, the base station uses the R first PMIs for beamforming that acts on a reference signal resource in a CSI process of the type B. Beamforming on the reference signal resource of the type B can be trained by measuring the reference signal resource of the type A, so that accuracy of the beamforming that acts on the reference signal resource of the type B is effectively improved, and system performance based on the reference signal resource of the type B is further improved.

For example, referring to <FIG> and <FIG>, <FIG> and <FIG> are a schematic diagram of a specific example of the channel state information reporting method in <FIG>. Configuration of a <NUM>-antenna port reference signal resource of the type A and corresponding channel quality measurement and reporting are used as an example. It is assumed that there are two reference signal resources in a CSI process: a reference signal resource <NUM> (a <NUM>-port reference signal resource) and a reference signal resource <NUM> (an <NUM>-port reference signal resource). The terminal obtains a <NUM>st first PMI and a first CQI such as an RS <NUM>-PMI and a CQI1-A based on channel quality measurement on the reference signal resource <NUM>. The CQI1-A is obtained based on a second PMI such as a PMI-<NUM> obtained after the first operational criterion, in other words, an interpolation is performed on the first PMI. Likewise, the user obtains a <NUM>nd first PMI and a second CQI such as an RS2-PMI and a CQI2-A based on measurement on the reference signal resource <NUM>. The CQI2-A is obtained based on a second PMI such as a PMI-<NUM> obtained after an interpolation is performed on the <NUM>nd first PMI. In addition, the terminal may obtain a third CQI such as a CQI3-A based on measurement on a second PMI such as a PMI-<NUM> obtained after an interpolation is performed on a direct sum of the <NUM>st first PMI and the <NUM>nd first PMI: the RS1-PMI and the RS2-PMI; or the terminal may obtain a fourth CQI such as a CQI4-A based on measurement on a second PMI such as a PMI-<NUM> obtained after a direct product is performed on the <NUM>st first PMI and the <NUM>nd first PMI such as the RS <NUM>-PMI and the RS2-PMI.

The channel state information reported by the terminal includes the following two cases:.

In addition, the base station may further determine, based on a <NUM>st first PMI and a <NUM>nd first PMI such as an RS <NUM>-PMI and an RS2-PMI of a reference signal resource of the type A reported by the terminal, a precoding matrix that acts on a reference signal resource of the type B and/or a quantity of ports of the reference signal resource of the type B.

The following describes an apparatus for implementing the foregoing method in the embodiments of the present invention with reference to the accompanying drawings.

Referring to <FIG> is a schematic structural diagram of a terminal according to an embodiment of the present invention.

As shown in <FIG>, the terminal <NUM> may include a determining module <NUM> and a reporting module <NUM>.

The determining module <NUM> is configured to: determine R first precoding matrix indicators PMIs of M first reference signal resources, and determine a channel quality indicator CQI based on the R first PMIs, where M and R are integers greater than or equal to <NUM>.

The reporting module <NUM> is configured to report channel state information, where the channel state information includes the R first PMIs and N CQIs, or the channel state information includes the R first PMIs and one CQI, the R first PMIs are used by a base station to determine P second PMIs according to a first operational criterion, a dimension of the second PMI is greater than a dimension of the first PMI, and P and N are integers greater than or equal to <NUM>.

Optionally, if the channel state information includes the R first PMIs and the N CQIs, the determining module <NUM> is specifically configured to determine the P second PMIs and/or the N CQIs based on the R first PMIs and the first operational criterion.

Alternatively, if the channel state information includes the R first PMIs and the CQI, the determining module <NUM> is specifically configured to determine one second PMI and one CQI based on the R first PMIs and a second operational criterion.

Optionally, if the channel state information includes the R first PMIs and the CQI, the channel state information further includes a CQI index indicator corresponding to the CQI.

Optionally, the first operational criterion and the second operational criterion are configured by the base station for the terminal, or the first operational criterion and the second operational criterion are predefined by the base station and the terminal.

Optionally, the first operational criterion and the second operational criterion include at least one of a direct product, a direct sum, and an interpolation.

It should be noted that the foregoing modules (the determining module <NUM> and the reporting module <NUM>) are configured to perform related steps of the foregoing method.

In this embodiment, the terminal <NUM> is presented in a form of a module. The "module" herein may be an application-specific integrated circuit (application-specific integrated circuit, ASIC), a processor and a memory that execute one or more software or firmware programs, an integrated logic circuit, and/or another component that can provide the foregoing functions. In addition, the determining module <NUM> may be implemented by using a processor and a memory in <FIG>. The reporting module <NUM> may report the channel state information to the base station by using a communications interface between the terminal and the base station.

Referring to <FIG> is a schematic structural diagram of a base station according to an embodiment of the present invention.

As shown in <FIG>, the base station <NUM> may include a reading module <NUM>.

The reading module <NUM> is configured to read channel state information reported by a terminal, where the channel state information includes R first PMIs and N CQIs, or the channel state information includes the R first PMIs and one CQI, the R first PMIs are used by the base station to determine P second PMIs according to a first operational criterion, a dimension of the second PMI is greater than a dimension of the first PMI, and R, P, and N are integers greater than or equal to <NUM>.

Optionally, the first operational criterion and the second operational criterion are configured by the base station for the terminal, or the first operational criterion and a second operational criterion are predefined by the base station and the terminal.

Optionally, the base station <NUM> further includes a determining module <NUM>, configured to determine a precoding matrix and/or a quantity of ports of a second reference signal resource based on the R first PMIs.

It should be noted that the foregoing modules (the reading module <NUM> and the determining module <NUM>) are configured to perform related steps of the foregoing method.

In this embodiment, the base station <NUM> is presented in a form of a module. The "module" herein may be an application-specific integrated circuit (application-specific integrated circuit, ASIC), a processor and a memory that execute one or more software or firmware programs, an integrated logic circuit, and/or another component that can provide the foregoing functions. In addition, the determining module <NUM> may be implemented by using a processor and a memory in <FIG>. The reading module <NUM> may read, by using a communications interface of the base station, the channel state information reported by the terminal.

As shown in <FIG>, the terminal <NUM>, the terminal <NUM>, the base station <NUM>, and the base station <NUM> may be implemented by using a structure of a communications device shown in <FIG>. The communications device <NUM> includes at least one processor <NUM>, at least one memory <NUM>, and at least one communications interface <NUM>. In addition, the communications device <NUM> may further include a general purpose component such as an antenna.

The processor <NUM> may be a general purpose central processing unit (CPU), a microprocessor, an application-specific integrated circuit (application-specific integrated circuit, ASIC), or one or more integrated circuits configured to control program execution of the foregoing solution.

The communications interface <NUM> is configured to communicate with another device or communications network, such as an Ethernet network, a radio access network (RAN), or a wireless local area network (Wireless Local Area Networks, WLAN).

The memory <NUM> may be a read-only memory (read-only memory, ROM), another type of static storage device that can store static information and an instruction, a random access memory (random access memory, RAM), or another type of dynamic storage device that can store information and an instruction, or may be an electrically erasable programmable read-only memory (Electrically Erasable Programmable Read-Only Memory, EEPROM), a compact disc read-only memory (Compact Disc Read-Only Memory, CD-ROM), another optical disk storage or optical disc storage (including a compact disc, a laser disc, an optical disc, a digital versatile disc, a Blu-ray disc, and the like), a disk storage medium or another magnetic storage device, or any other medium that can be used to carry or store expected program code in a form of an instruction or a data structure and that can be accessed by a computer. However, this is not limited thereto. The memory may exist independently and is connected to the processor by using a bus. Alternatively, the memory may be integrated with the processor.

The memory <NUM> is configured to store application program code used to execute the foregoing solution, and the processor <NUM> controls and executes the program code. The processor <NUM> is configured to execute the application program code stored in the memory <NUM>.

If the communications device shown in <FIG> is a terminal, the code stored in the memory <NUM> may be used to perform the channel state information reporting method performed by the terminal provided above. For example, the terminal determines R first precoding matrix indicators PMIs of M first reference signal resources, and determines a channel quality indicator CQI based on the R first PMIs. Finally, the terminal reports channel state information, where the channel state information includes the R first PMIs and N CQIs, or the channel state information includes the R first PMIs and one CQI, the R first PMIs are used by a base station to determine P second PMIs according to a first operational criterion, and a dimension of the second PMI is greater than a dimension of the first PMI.

If the communications device shown in <FIG> is a terminal, the code stored in the memory <NUM> may be used to perform the channel state information reporting method performed by the terminal provided above. For example, the terminal determines channel state information, where the channel state information includes first channel state information of a first reference signal resource and second channel state information of a second reference signal resource. Then the terminal determines a reporting mode of the channel state information, and reports the channel state information based on the reporting mode.

If the communications device shown in <FIG> is a base station, the code stored in the memory <NUM> may be used to perform the channel state information reading method performed by the base station provided above. For example, the base station reads channel state information reported by a terminal, where the channel state information includes R first PMIs and N CQIs, or the channel state information includes the R first PMIs and one CQI, the R first PMIs are used by the base station to determine P second PMIs according to a first operational criterion, and a dimension of the second PMI is greater than a dimension of the first PMI.

If the communications device shown in <FIG> is a base station, the code stored in the memory <NUM> may be used to perform the channel state information reading method performed by the base station provided above. For example, the base station reads channel state information reported by a terminal, where the channel state information includes first channel state information of a first reference signal resource and second channel state information of a second reference signal resource, and a reporting mode of the channel state information is determined by the terminal based on the channel state information.

If the communications device shown in <FIG> is a base station, the processor <NUM> may be a processor on a board of the base station, or may be one or more integrated circuits or chips on a board of the base station. In addition, the memory <NUM> may be integrated with the processor <NUM>, or the memory <NUM> and the processor <NUM> may be disposed separately.

An embodiment of the present invention further provides a computer storage medium. The computer storage medium may store a program. When the program is executed, some or all steps of any one of the channel state information reporting method and the channel state information reading method recorded in the method embodiments are included.

It should be noted that, to make the description brief, the foregoing method embodiments are expressed as a series of actions. However, a person skilled in the art should appreciate that the present invention is not limited to the described action sequence, because according to the present invention, some steps may be performed in other sequences or performed simultaneously. In addition, a person skilled in the art should also appreciate that all the embodiments described in the specification are example embodiments, and the related actions and modules are not necessarily mandatory to the present invention.

In the several embodiments provided in this application, it should be understood that the disclosed apparatus may be implemented in other manners. In addition, the displayed or discussed mutual couplings or direct couplings or communication connections may be implemented through some interfaces. The indirect couplings or communication connections between the apparatuses or units may be implemented in electronic or other forms.

When the integrated unit is implemented in the form of a software functional unit and sold or used as an independent product, the integrated unit may be stored in a computer-readable storage. Based on such an understanding, the technical solutions of the present invention essentially, or the part contributing to the prior art, or all or some of the technical solutions may be implemented in the form of a software product. The software product is stored in a storage and includes several instructions for enabling a computer device (which may be a personal computer, a server, a network device, or the like) to perform all or some of the steps of the methods described in the embodiments of the present invention. The foregoing storage includes: any medium that can store program code, such as a USB flash drive, a read-only memory (ROM, Read-Only Memory), a random access memory (RAM, Random Access Memory), a removable hard disk, a magnetic disk, or an optical disc.

A person of ordinary skill in the art may understand that all or some of the steps of the methods in the embodiments may be implemented by a program instructing relevant hardware. The program may be stored in a computer-readable storage. The storage may include a flash memory, a read-only memory (English: Read-Only Memory, ROM for short), a random access memory (English: Random Access Memory, RAM for short), a magnetic disk, an optical disc, or the like.

Claim 1:
A channel state information reporting method, comprising:
determining, by a terminal, R first precoding matrix indicators PMIs based on M first reference signal resources, and determining at least one channel quality indicator CQI based on the R first PMIs, wherein M and R are integers greater than <NUM>; and
reporting, by the terminal, channel state information, wherein the channel state information comprises the R first PMIs and N CQIs, the R first PMIs are used by a base station to determine P second PMIs, a dimension of each of the P second PMIs is greater than a dimension of each of the R first PMIs, which indicates that a quantity of rows of a precoding matrix of each of the P second PMIs is greater than a quantity of rows of a precoding matrix of each of the R first PMIs; and P and N are integers greater than or equal to <NUM>,
wherein
if the channel state information comprises the R first PMIs and a plurality of CQIs, the determining the at least one channel quality indicator CQI based on the R first PMIs comprises:
determining, by the terminal, the P second PMIs and the plurality of CQIs based on the R first PMIs and a first operational criterion; and
if the channel state information comprises the R first PMIs and one CQI, the determining the at least one channel quality indicator CQI based on the R first PMIs comprises:
determining, by the terminal, one second PMI and the CQI based on the R first PMIs and a second operational criterion;
wherein the first operational criterion and the second operational criterion comprise at least one of a direct product, a direct sum, and an interpolation, and
wherein the first operational criterion and the second operational criterion are configured by the base station for the terminal, or the first operational criterion and the second operational criterion are predefined by the base station and the terminal.