Terminal device-implemented method and network device-implemented method

Abstract

A method and device are provided that can reduce the total overhead of channel state information (CSI) transmission. In a network including a network device and a terminal device served by the network device, a method implemented in the terminal device includes: performing channel estimation between the terminal device and the network device over a predetermined frequency range for a set of beams having different spatial directions; determining first and second indication information based on the channel estimation; and transmitting the first indication information in a first portion of a CSI report and the second indication information in a second portion of the CSI report to the network device, wherein the first indication information indicates at least one beam selected from the set of beams, and the second indication information indicates frequency-related information for the at least one selected beam at a plurality of frequency locations within the predetermined frequency range.

Description

[Technical Field]

[0001] TECHNICAL FIELD Embodiments of the present disclosure relate generally to the field of telecommunications, and more particularly to methods and devices used for channel state information (CSI) transmission. [Background technology]

[0002] Various telecommunication standards are being developed to provide public protocols that enable communication between various wireless devices at city, national, regional, and global levels. An example of an emerging telecommunication standard is New Radio (NR), e.g., 5G wireless access.

[0003] NR is a set of enhancements to the LTE mobile standard promulgated by the 3rd Generation Partnership Project (3GPP®). NR is designed to better support mobile broadband Internet access by increasing spectral efficiency, reducing costs, improving services, utilizing new spectrum, and better integration with other open standards that use OFDMA with cyclic prefix (CP) on the downlink (DL) and uplink (UL). NR is also designed to support beamforming, multiple input multiple output (MIMO) antenna technology, and carrier aggregation.

[0004] However, as the demand for mobile broadband access continues to grow, further improvements to NR technology are required. These improvements may be applicable to other multiple access technologies and telecommunication standards that employ such technologies. For example, in a communication system, a receiving terminal device typically estimates channel state information (CSI) of the communication channel between the terminal device and network equipment and feeds it back to the network equipment so that the network equipment can control transmission based on the current channel conditions indicated by the CSI. NR technology proposes reporting channel attributes of the wideband and subbands, as well as channel attributes of different beams (in a MIMO system), in the CSI, but this increases the overhead of CSI transmission. Summary of the Invention [Problem to be solved by the invention]

[0005] Generally, the exemplary embodiments of the present disclosure provide methods and devices for use in channel state information (CSI) transmission. [Means for solving the problem]

[0006] In a first aspect, a method implemented in a terminal device is provided, comprising: performing channel estimation between the terminal device and a network device over a predetermined frequency range for a set of beams having different spatial directions, determining first and second indication information based on the channel estimation, and transmitting the first indication information in a first portion of a Channel State Information (CSI) report to the network device and the second indication information in a second portion of the CSI report to the network device, wherein the first indication information indicates at least one beam selected from the set of beams and the second indication information indicates frequency-related information for the at least one selected beam at a plurality of frequency locations within the predetermined frequency range.

[0007] In a second aspect, a method is provided implemented in a terminal device, the method comprising: performing channel estimation between the terminal device and a network device over a predetermined frequency range for a set of beams having different spatial directions, determining indication information based on the channel estimation, and transmitting the indication information in a first portion of a Channel State Information (CSI) report to the network device, the indication information indicating at least one beam selected from a plurality of beams for a plurality of frequency locations within the predetermined frequency range.

[0008] In a third aspect, a method implemented in a network device is provided, comprising: receiving, from a terminal device, a channel state information (CSI) report determined by channel estimation; and generating CSI based on first indication information and second indication information to control transmission to and from the terminal device, wherein a first portion of the CSI report comprises at least the first indication information indicating at least one beam of a beam set, and a second portion of the CSI report comprises at least the second indication information, and the second indication information indicates multiple frequency locations for the at least one selected beam within a predetermined frequency range.

[0009] In a fourth aspect, there is provided a method implemented in a network device, comprising: receiving, from a terminal device, a channel state information (CSI) report determined by channel estimation; and generating CSI based on first indication information and second indication information to control transmission to and from the terminal device, wherein a first portion of the CSI report comprises at least the indication information, and the indication information indicates at least one beam selected from a plurality of beams for a plurality of frequency locations within a predetermined frequency range.

[0010] In a fifth aspect, there is provided a terminal device comprising a processor and a memory coupled to the processing unit and having instructions stored thereon, the instructions being adapted, when executed by the processing unit, to perform the method of either the first or second aspect.

[0011] In a sixth aspect, there is provided a network device comprising: a processor; and a memory coupled to the processing unit and having instructions stored thereon, the instructions, when executed by the processing unit, performing a method of any of the third and fourth aspects.

[0012] In a seventh aspect, there is provided a computer-readable medium having stored thereon instructions that, when executed on at least one processor, cause the at least one processor to perform a method of either the first or second aspect.

[0013] In an eighth aspect, there is provided a computer-readable medium having stored thereon instructions that, when executed on at least one processor, cause the at least one processor to perform the method of either the first or second aspect.

[0014] Other features of the present disclosure will be readily apparent from the following description. [Brief explanation of the drawings]

[0015] Hereinafter, several embodiments of the present disclosure will be described in more detail in the drawings, which will make the above and other objects, features, and advantages of the present disclosure more apparent.

[0016] [Figure 1] FIG. 1 is a block diagram of a communication environment in which embodiments of the present disclosure can be implemented.

[0017] [Figure 2] FIG. 1 is a flow diagram illustrating a process for channel state information (CSI) transmission according to some embodiments of the present disclosure.

[0018] [Figure 3] 10 is a graph of the time domain response and frequency domain response of a beam according to some other embodiments of the present disclosure.

[0019] [Figure 4]10 is a graph of the frequency domain response of a beam according to some other embodiments of the present disclosure.

[0020] [Figure 5] 10 is a graph of the time domain response of a beam according to some other embodiments of the present disclosure.

[0021] [Figure 6] 10 is a graph of the time domain response of a beam according to some other embodiments of the present disclosure.

[0022] [Figure 7] FIG. 10 is a flow diagram illustrating a process for CSI transmission according to some other embodiments of the present disclosure.

[0023] [Figure 8] 1 illustrates a flow diagram of an exemplary method according to some embodiments of the present disclosure.

[0024] [Figure 9] 10 shows a flow diagram of an exemplary method according to some other embodiments of the present disclosure.

[0025] [Figure 10] 10 shows a flow diagram of an example method according to some further embodiments of the present disclosure.

[0026] [Figure 11] 10 shows a flow diagram of an example method according to yet some embodiments of the present disclosure.

[0027] [Figure 12] FIG. 1 is a schematic block diagram of a device suitable for implementing embodiments of the present disclosure.

[0028] In all figures, the same or similar reference numerals refer to the same or similar parts. DETAILED DESCRIPTION OF THE INVENTION

[0029] The principles of the present disclosure will be described below with reference to several exemplary embodiments. It should be understood that these embodiments are described merely for the purpose of explanation and description, to assist those skilled in the art in understanding and implementing the present disclosure, and do not imply any limitation on the scope of the present disclosure. The disclosure described herein can be implemented in various ways other than those described below.

[0030] In the following description and claims, unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs.

[0031] For example, the term "network equipment" or "base station" (BS) used in the text refers to a device capable of providing or managing a cell or coverage area in which terminal equipment can communicate. Examples of network equipment include, but are not limited to, a Node B (Node B or NB), an evolved Node B (eNode B or eNB), a Node B in NR radio access (gNB), a remote radio unit (RRU), a radio head (RH), a remote radio head (RRH), and a low-power node (e.g., a femto node, a pico node, etc.). For purposes of explanation, the following text will use a gNB as an example of network equipment for reference, and will describe some embodiments.

[0032] As used herein, the term "terminal equipment" refers to any device capable of wireless or wired communications. Examples of terminal equipment include, but are not limited to, user equipment (UE), personal computers, desktop computers, mobile phones, cell phones, smart phones, personal digital assistants (PDAs), handheld computers, image capture devices (e.g., digital cameras), gaming devices, music storage and playback devices, or Internet devices that enable wireless or wired Internet access and browsing capabilities.

[0033] When used in the text, the singular forms "a," "one," and "the" are intended to include the plural unless the text clearly indicates otherwise. The term "comprises" and variations thereof should be interpreted as open-ended, meaning "including, but not limited to." The term "based on" should be interpreted as "based at least in part on." The terms "one embodiment" and "embodiment" should be interpreted as "at least one embodiment." The term "another embodiment" should be interpreted as "at least one other embodiment." The terms "first," "second," etc. can refer to different or identical objects. Other definitions (express or implied) may also be included in the text that follows.

[0034] In some instances, values, procedures, or devices are referred to as "best," "lowest," "highest," "minimum," "maximum," etc. It should be understood that such descriptions are intended to indicate choices among alternatives of the functionality used, and that such choices are not necessarily better, smaller, higher, or otherwise more preferable than other choices.

[0035] 1 illustrates an exemplary communication network 100 in which embodiments of the present disclosure can be implemented. Network 100 includes network device 110 and terminal devices 120 serviced by network device 110. The service area of ​​network device 110 is referred to as a cell 102. It should be understood that the number of network devices and terminal devices is for illustrative purposes only and does not imply any limitation. Network 100 may include any suitable number of network devices and terminal devices suitable for implementing embodiments of the present disclosure. Although not shown, it should be understood that one or more terminal devices may be located within cell 102 and be serviced by network device 110.

[0036] In the communication network 100, the network equipment 110 can send data and control information to the terminal equipment 120, and the terminal equipment 120 can also send data and control information to the network equipment 110. The link from the network equipment 110 to the terminal equipment 120 is called the downlink (DL) or forward link, and the link from the terminal equipment 120 to the network equipment 110 is called the uplink (UL) or reverse link.

[0037] Depending on the communication technology, network 100 may be a code division multiple access (CDMA) network, a time division multiple access (TDMA) network, a frequency division multiple access (FDMA) network, an orthogonal frequency division multiple access (OFDMA) network, a single carrier-frequency division multiple access (SC-FDMA) network, or any other network. Communications discussed with respect to network 100 may conform to any suitable standard, including, but not limited to, New Radio Access (NR), Long Term Evolution (LTE), LTE Evolution, LTE-Advanced (LTE-A), Wideband Code Division Multiple Access (WCDMA), Code Division Multiple Access (CDMA), cdma2000, and Global System for Mobile Communications (GSM). Communications may also be performed based on any currently known or future generation of communication protocols. Examples of communication protocols include, but are not limited to, first generation (1G), second generation (2G), 2.5G, 2.75G, third generation (3G), fourth generation (4G), 4.5G, and fifth generation (5G) communication protocols. The techniques described herein may be used in the wireless networks and radio technologies mentioned above as well as other wireless networks and radio technologies. For clarity, some aspects of LTE technology are described below, and LTE terminology is used in much of the description below.

[0038] During communication, terminal device 120 is configured to estimate and report channel state information (CSI) of the communication channel between terminal device 120 and network device 110. CSI may be determined by terminal device 120 using downlink reference signals transmitted by network device 110.

[0039] Typically, LTE uses an implicit rank indicator / precoding matrix indicator / resource partitioning information / channel quality indicator (RI / PMI / RPI / CQI) feedback framework for CSI feedback, which is recognized as "implicit" in that the CQI / PMI / RI (and CRI in the LTE specification) are derived from a codebook.

[0040] As mentioned above, RI is information about channel rank and indicates the number of streams that can be received via the same time-frequency resource. RI is determined by long-term fading of the channel, so it can usually be fed back at a longer period than PMI or CQI. PMI is a value indicating the spatial characteristics of the channel and indicates the precoding matrix indicator of the network equipment preferred by the terminal equipment. RPI corresponds to the allocation of power domain resources between the serving network equipment 110 and one or more non-serving network equipment. CQI is information indicating the strength of the channel and indicates the received SINR that can be obtained when the network equipment uses PMI.

[0041] CSI feedback reflects the average channel condition over the entire or partial system bandwidth. Measures such as RI, PMI, and RPI can be calculated to reflect the average channel condition over the entire system bandwidth (e.g., wideband RI / PMI). The PMI over the system bandwidth can indicate the index of a beam for the system bandwidth, and the RPI over the system bandwidth can indicate the gain of a beam over the system bandwidth. Some measures, such as PMI and CQI, can be calculated per subband. The PMI for a subband can indicate the gain of a beam in that subband, and the RPI for a subband can indicate the phase shift of a beam in that subband.

[0042] When a terminal device reports CSI for one beam, the terminal device can determine parameters defining RI, PMI, RPI, and / or CQI based on channel estimation. These parameters can be reported to a network device to identify a codeword from a codebook. A codebook defined for transmission using one beam can also be referred to as a Type I codebook, in which each codeword can be defined as follows:

number

number

[0043] To allow the network equipment to determine the codeword for the beam, l, m and φ are determined by the terminal equipment. n It is necessary to report parameters including: Only CSI for one beam is required, which limits overhead.

[0044] In some other situations, the terminal device is configured to report CSI for more than one beam (e.g., L beams). Information about the beams is needed to determine the codeword from the codebook. In such a situation, the codeword can be defined by the terminal device based on information about different beams, for example, as follows:

number

[0045] To allow the network equipment to determine the codeword, for each of the L beams, the wideband information m1 (i) , m2 (i) and p l、i (1) , and subband information p l、i (2) and φ l、i Parameters including

[0000] need to be reported by the terminal device, which increases the overhead of CSI transmission. The total overhead of CSI transmission depends on the number of beams and rank order reported. Table 1 below shows the overhead of CSI transmission in several situations. [Table 1]

[0046] As can be seen from Table 1, the overhead of CSI feedback is large, sometimes reaching around 600 bits. Furthermore, when the system bandwidth is large, CSI feedback for each subband within the multiple subbands in the system bandwidth must be transmitted, which further increases the overhead as the number of subbands increases. Therefore, it is necessary to compress the overhead of CSI transmission.

[0047] There are already several solutions for CSI compression. In one solution, a terminal device transmits CSI at several frequency positions in the frequency domain. After receiving CSI feedback, a network device interpolates the CSI received at several frequency positions to determine CSI at other frequency positions. This method can determine CSI at all frequency positions and reduce the total overhead of CSI transmission. However, the CSI overhead is still large and increases with an increase in system bandwidth or the number of subbands.

[0048] In an embodiment of the present disclosure, a solution for CSI transmission is provided, in which a terminal device determines indication information related to the frequency domain and includes it in a CSI report, and the frequency-related indication information and other indication information related to a beam in the spatial domain can be used by a network device to generate CSI.

[0049] The principles and embodiments of the present disclosure will now be described in detail with reference to Fig. 2. Fig. 2 shows a process 200 for UCI transmission according to an embodiment of the present disclosure. For discussion purposes, the process 200 will be described with reference to Fig. 1. The process 200 may involve the network device 110 and the terminal device 120 in Fig. 1.

[0050] The terminal device 120 performs channel estimation between the terminal device 120 and the network device 110 over a predetermined frequency range for a set of beams having different spatial directions (205). The terminal device 120 can perform channel estimation using various procedures. Typically, the terminal device 120 can receive a reference signal from the network device 110. The reference signal can be any signal sequence known to both the terminal device 120 and the network device 110. By comparing the received reference signal with the true reference signal, the terminal device 120 can estimate the channel conditions between the terminal device 120 and the network device 110.

[0051] The terminal device 120 determines (210) first indication information and second indication information based on the channel estimation. The first indication information indicates at least one beam selected from the beam set, and the second indication information indicates frequency-related information for the selected at least one beam at multiple frequency positions within a predetermined frequency range. Based on the channel estimation, the terminal device 120 selects a predetermined number of beams from the beam set and reports them to the network device. Each of the selected beam(s) can be indicated using a corresponding index, for example, an index associated with the horizontal and vertical directions.

[0052] According to an embodiment of the present disclosure, additional indication information in the frequency domain (i.e., second indication information) is determined for CSI feedback. The frequency range can also be referred to as wideband because it has the system bandwidth of the network 100. For each selected beam, the second indication information indicates corresponding frequency-related information. In some embodiments, the frequency-related information can be used to extend the codeword for CSI from Equation 2 as follows:

number

[0053] In some embodiments, the second indication information may be indicated using a result of a time-frequency domain transformation performed in the terminal device 120. For example, the second indication information may be indicated using elements selected from a matrix obtained by a Discrete Fourier Transform (DFT) or a Fast Fourier Transform (FFT), where the DFT or FFT is typically performed in the terminal device 120, particularly in an OFDM network. In the DFT matrix, each row corresponds to one subcarrier, and each column corresponds to a delay value in the time domain of a channel path associated with a selected beam. Therefore, elements at a specific row and a specific column in the DFT matrix may be used as frequency-related information for CSI feedback.

[0054] An example DFT matrix is ​​provided below:

number

number

[0055] In some embodiments, the frequency-related information f for the i-th beam is i may be a vector, and includes elements corresponding to multiple frequency positions (e.g., frequency positions of different subbands within a frequency range). i The length of the vector for f depends on the number of frequency locations (e.g., subbands), which can be set by the network device 110. For example, the network device 110 can inform the terminal device 120 that it needs to report frequency-related information for S subbands, in which case the frequency-related information f i The length of the frequency-related information f i The k-th element in the vector for Ds k、i It can be expressed as:

[0056] In some embodiments, since the DFT matrix can be obtained in the network device 110 and the subbands to be considered are also set by the network device 110, the terminal device 120 can calculate the delay value associated with the selected beam (τ for the path associated with the i-th beam). i ) can be determined as the second indication. In these embodiments, the frequency-related information for each selected beam includes an associated delay value and a predetermined index (e.g., s) of a plurality of frequency locations. k ) can be shown in combination.

[0057] 3 shows graphs 302 and 304 for the time domain response and the frequency domain response, respectively. The graph 302 for the time domain response of all beams is

number

number

[0058] In some embodiments, instead of using a range of 0 to N-1, the delay value τ i The range of values ​​for τ may be configured, for example, via Radio Resource Control (RRC) signaling or activated by a Medium Access Control (MAC)-Control Element (CE). i The range of is determined by the length and / or numerology of the cyclic prefix used in network 100.

[0059] In some embodiments, except for the second indication information, other information in the CSI report is reused from the normal CSI feedback framework. For example, the first indication information indicating the selected beam(s) can be represented by the horizontal and vertical indices of the selected beam(s), thereby providing, for example, a v that can be recognized as wideband PMI. m1 (i) 、m2 (i)In some embodiments, the terminal device 120 can determine a third indication based on the channel estimation. The third indication can indicate a gain for at least one selected beam across a frequency range. For example, the third indication can indicate a wideband RPI (e.g., p l、i (1) ) can be.

[0060] The terminal device 120 may further determine a fourth indication based on the channel estimation, the fourth indication including a respective co-phase shift (e.g., φ) in the time domain for the at least one selected beam to be applied across a predetermined frequency range. l、i The fourth indication information can be recognized as wideband information.

[0061] Referring again to FIG. 2 , terminal device 120 transmits (215) first indication information in a first portion of the CSI report and transmits (215) second indication information in a second portion of the CSI report. A CSI report typically includes two parts: a first part (also referred to as part 1) and a second part (also referred to as part 2). The first part can be transmitted by terminal device 120 to network device 110 before the second part. The two parts can be coded separately. The indication information indicating the beam(s) selected by terminal device 120 is typically in the first part, and network device 110 can first decode the first part to determine which beam(s) are expected.

[0062] In an embodiment in which the terminal device 120 determines the third and fourth indication information, the terminal device 120 may further include the determined information in a second part of the CSI report that the terminal device 120 transmits to the network device 110. After receiving the first and second parts of the CSI report, the network device 110 generates 220 the CSI based on the received indication information. For example, the network device 110 determines a codeword from a CSI codebook based on the received indication information and controls transmission with the terminal device 120.

[0063] In some embodiments, the gain of the beam in each subband is not determined or included in the CSI report, which mainly includes a first indication (e.g., v) indicating the selected beam(s). m1 (i) 、m2 (i) ) and a second indication (delay value τ i ) and a third indication over a frequency range (p l、i (1) ) and a fourth indication (φ l、i ) That is, since the gain and co-phase shift of each selected beam are reported in the time domain, they are not reported separately for each subband at each frequency location in the CSI report, which can contribute to reducing the overhead of report transmission. In some embodiments, the CSI report can further include another indication information indicating a channel quality indicator (CQI) corresponding to the frequency range. The CQI can be included in the first part of the report.

[0064] In these embodiments, after receiving the instruction information, the network device 110 can determine a codeword from a codebook set for the CSI based on the received instruction information to generate the CSI. For example, the codeword can be determined based on the above Equation 3. The codeword can be determined for each subcarrier (frequency position). When there is only one beam in the communication channel, v m1 (i) 、m2 (i) The beam shown in is identical for all frequency locations, the gain of the beam across the frequency range is identical for all frequency locations, and the co-phase shift in the time domain is also identical for all frequency locations across the system bandwidth. k The component phase information in φ l、i e -j2πs kτ i , which is determined by the co-phase shift and delay values ​​in the time domain. In this situation, the frequency domain response of the single beam in all frequency ranges remains unchanged, as shown in graph 402 of FIG.

[0065] In some embodiments, when more than two beams are selected, the gain for each selected beam at a frequency location can be determined by weighting the second, third, and fourth instructions for each selected beam. For example, if there are two selected beams, the second instruction can include delay values ​​τ and τ for the two beams, the third instruction can include gains p and p for the two beams applied across a frequency range, and the fourth instruction can include common phase shifts φ and φ in the time domain for the two beams applied at different frequency locations. Then, as shown in curve 410 in graph 404 of FIG. 4, the gains of the two beams at each frequency location f can be calculated as p, v, φ, e. j2πfτ 1+p2v2φ2e j2πfτ 2. Other methods can also be used to determine the gains in different sub-bands based on the gains across a frequency range.

[0066] In some embodiments, to realize subband-based CSI reporting, some subband information, rather than all subband information, is determined and transmitted in the report. For example, when two or more beams are selected (e.g., L beams), the terminal device 120 further determines fifth indication information. The fifth indication information indicates the gain of at least one beam in a beam subset at a subset of multiple frequency locations. For example, one or more strongest beams (e.g., Lsb) may be selected from the L beams, and the subband-based gains of these beams may be determined as the fifth indication information. In some embodiments, multiple frequency locations within a frequency range may be divided into two or more subsets. The strongest beam is searched for in each subset. The fifth indication information may be considered as subband PMI, and p l、i (2) Transmitting fewer subband gains can also reduce the CSI overhead. The fifth indication information can be reported in the second part of the CSI report.

[0067] 5, graph 502 shows eight beams with different delay values ​​distributed in the time domain, and graph 504 shows the frequency domain response. Depending on the strength of the frequency domain response, beams 1, 2, 4, and 8 are selected in a first set of frequency locations (set 1), and corresponding gains at these frequency locations of the selected beams can be determined and included in the fifth instruction. Also, beams 1, 2, 7, and 8 are selected in a second set of frequency locations (set 2), and corresponding gains at these frequency locations of the selected beams can be determined and included in the fifth instruction.

[0068] In some embodiments, instead of including the fourth indication information for all beams at all frequency locations, the CSI report can include a sixth indication information. The sixth indication information indicates the co-phase shift of each of at least one stronger beam at a subset of frequency locations. In the example of FIG. 5, the fourth indication information can indicate the co-phase shift of beams 1, 2, 4, and 8 at a first set of frequency locations and the co-phase shift of beams 1, 2, 7, and 8 at a second set of frequency locations. Transmitting fewer subband co-phase shifts can further reduce CSI overhead. The sixth indication information can also be reported in a second part of the CSI report.

[0069] In some embodiments, the CSI report may further include another indication information, which indicates a channel quality indicator (CQI) corresponding to a frequency range or a plurality of frequency locations and respective CQIs corresponding thereto. The CQI-related information may be included in the first part of the CSI report.

[0070] In some embodiments, the terminal device 120 may transmit the CSI with a delay value τ i In order to transmit the delay value in the second indication information, the delay value in the second indication information may be quantized into multiple bits. To ensure accuracy and to avoid using a large number of bits and increasing overhead, several embodiments of quantization for the delay value will be described below. In addition, quantization of other information in the CSI report may be performed by any existing method or any other method developed in the future.

[0071] In some embodiments, terminal device 120 may use delay value τ i In one embodiment, for each delay value of the selected beam, the terminal device 120 quantizes the delay value τ iA first number of bits for quantizing the delay value can be determined based on the delay value τ, where the first number is greater than the number of bits determined for another delay value having a smaller magnitude. For example, if the delay values ​​range from 0 to X and the delay value τ i The smaller the magnitude of τ, the larger the first number and the delay value τ i The larger the magnitude of τ, the smaller the first number. In this way, more bits are used to obtain a small delay value τ i Quantizing delay values ​​can increase the accuracy and resolution of transmission compared to other smaller delay values. Table 2 below provides examples of quantization methods for delay values ​​having different values. In this example, the delay values ​​can have values ​​in the range of 0 to 144. It should be understood that Table 2 is provided for illustrative purposes, and other quantization methods can be considered. [Table 2]

[0072] In another embodiment, the terminal device 120 may determine, for each delay value of a selected beam, a second number of bits for quantizing the delay value based on the gain of at least one selected beam. The second number is greater than the number of bits determined for another delay value corresponding to another beam having a higher gain. All selected beams are ordered based on their gains. In some examples, the first beam in the time domain has the highest gain, so a certain number (e.g., K) of delay values ​​for the first K beams may be assigned a larger number of bits, and the remaining delay values ​​may be assigned a smaller number of bits. Table 3 below provides examples of quantization methods for different delay values. It should be understood that Table 3 is provided for illustrative purposes, and other quantization methods may be considered. [Table 3]

[0073] In some embodiments, during synchronization, the first beam may not be the strongest beam (does not have the highest gain). For example, graph 602 in FIG. 6 shows time-domain responses for different delay values, where the first beam corresponding to response 610 is the synchronized first beam, while the seventh beam corresponding to response 612 is the actual first beam with the smallest actual delay value. In these embodiments, terminal device 120 can obtain a circularly shifted version of the delay value by shifting the delay value by one circular shift value for each delay value to modify the delay value. The circular shift value can be set by network device 110. As shown in graph 604 in FIG. 6, after the circular shift, the seventh beam (the actual first beam with the smallest gain) is shifted to become the first beam, and all beams are converged in a specific time range. Terminal device 120 can then determine a second number of bits based on the gain of the circularly shifted version of the delay value.

[0074] After determining the number of bits for quantization, terminal device 120 may quantize the delay value to a first number of bits (for magnitude-based quantization embodiments) or a second number of bits (for gain-based quantization embodiments). In some embodiments, if determining the second number of bits based on a circularly shifted version of the delay value, terminal device 120 may quantize the circularly shifted version of the delay value to the second number of bits.

[0075] In the above embodiment, the frequency-related information is independent information (i.e., τ i ) in the CSI report. In some other embodiments, the frequency-related information may be sent in a more implicit manner along with indication information about the selected beam(s). Such an embodiment is described below with reference to FIG. 7. FIG. 7 shows a process 700 for UCI transmission according to an embodiment of the present disclosure. For discussion purposes, process 700 is described with reference to FIG. 1. Process 700 may involve network device 110 and terminal device 120 of FIG. 1.

[0076] The terminal device 120 performs channel estimation between the terminal device 120 and the network device 110 over a predetermined frequency range for a set of beams having different spatial directions (705). The operations at 705 are similar to those at 205, and therefore will not be described in detail here for the sake of brevity.

[0077] The terminal device 120 determines (710) the indication information based on the channel estimation. The indication information indicates at least one beam selected from a plurality of beams for a plurality of frequency locations within a predetermined frequency range. According to embodiments, the indication information is beam-specific in both spatial-related information and frequency-related information. In other words, the indication information applies to all frequency locations. In these embodiments, a codebook for CSI can be newly designed to indicate such information. For example, from Equation 2, the codeword for CSI can be expanded as follows:

number

number

[0078] Terminal device 120 transmits (715) the indication information in the first part of the CSI report to network device 110. Unlike the embodiment described with respect to Figure 2, the indication information indicative of the frequency-related information is reported to network device 110 together with the indication information indicative of the selected beam(s).

[0079] In addition to the determined indication information, the CSI report may further include a second portion, which may include other information, such as indication information indicating a respective gain in the time domain for at least one selected beam applied across a predetermined frequency range, indication information indicating a respective co-phase shift in the time domain for at least one selected beam applied across a predetermined frequency range, indication information indicating a gain of at least one beam in a beam subset at at least one frequency location among a plurality of frequency locations, and / or indication information indicating a respective co-phase shift in the time domain for at least one beam in a beam subset at at least one frequency location. Such indication information may be similar to the indication information described in the above-described embodiment of FIG. 2. In some embodiments, the first portion of the CSI report may further include a channel quality indicator (CQI) corresponding to the wideband or respective CQIs corresponding to a plurality of frequency locations. The first portion may be transmitted to the network device 110 first, and then the second portion may be transmitted.

[0080] After receiving the CSI report, the network device 110 generates CSI based on the received instruction information (720). For example, the network device 110 controls transmission with the terminal device 120 by determining a codeword from a CSI codebook based on the received instruction information.

[0081] 8 illustrates a flowchart of an exemplary method 800 according to some embodiments of the present disclosure. Method 800 may be implemented in terminal device 120 as shown in FIG. 1. For purposes of discussion, method 800 will be described from the perspective of terminal device 120 with reference to FIG. 1.

[0082] In block 810, the terminal device 120 performs channel estimation between the terminal device and the network device over a predetermined frequency range for a set of beams having different spatial directions. In block 820, the terminal device 120 determines first indication information and second indication information based on the channel estimation. The first indication information indicates at least one beam selected from the set of beams, and the second indication information indicates frequency-related information for the selected at least one beam at multiple frequency locations within the predetermined frequency range. In block 830, the terminal device 120 transmits the first indication information in a first portion of a channel state information (CSI) report to the network device and transmits the second indication information in a second portion of the CSI report to the network device.

[0083] In some embodiments, determining the second indication information includes determining as the second indication information at least one delay value in the time domain associated with at least one selected beam applied across a predetermined frequency range, and indicating frequency-related information for each selected beam by a combination of the associated delay value and a predetermined index of a plurality of frequency locations.

[0084] In some embodiments, the multiple frequency locations are configured by the network equipment.

[0085] In some embodiments, the method further includes determining third and fourth indication information based on the channel estimation, and transmitting the third and fourth indication information in a second portion of the CSI report to network equipment, where the third indication information indicates respective gains in the time domain for the at least one selected beam applied across a predetermined frequency range, and the fourth indication information indicates respective co-phase shifts in the time domain for the at least one selected beam applied across the predetermined frequency range.

[0086] In some embodiments, the first indication indicates a beam subset selected from a beam set, the beam subset including two or more beams. The method further includes determining fifth indication information based on the channel estimation and transmitting the fifth indication information in a second portion of the CSI report to network equipment. The fifth indication information indicates a gain of at least one beam in the beam subset at a subset of a plurality of frequency locations. Such at least one beam is stronger than other beams in the beam subset.

[0087] In some embodiments, the method further includes determining, based on the channel estimation, sixth indication information and transmitting the sixth indication information in a second portion of the CSI report to the network equipment, the sixth indication information indicating a co-phase shift of each of the at least one beam in the beam subset at the at least one frequency location.

[0088] In some embodiments, the first portion of the CSI report further comprises another indication, the another indication indicating a channel quality indicator (CQI) corresponding to a frequency range or a plurality of frequency locations and respective CQIs corresponding thereto.

[0089] In some embodiments, the transmitting further includes, for each delay value of the at least one delay value, determining a first number of bits for quantization of the delay value based on a magnitude of the delay value, quantizing the delay value to the first number of bits, and transmitting the first number of bits to the network device, the first number being greater than a number of bits determined for another delay value having a smaller magnitude.

[0090] In some embodiments, the transmitting further includes, for each beam of the at least one beam, determining a second number of bits for quantization of the delay value based on a gain of the selected at least one beam, quantizing the delay value to the second number of bits, and transmitting the second number of bits to the network device, the second number being greater than the number of bits determined for another delay value corresponding to another beam having a higher gain.

[0091] In some embodiments, determining the second number of bits includes modifying the delay value by shifting the delay value by one circular shift value to obtain a circular shifted version of the delay value, and determining the second number of bits based on a gain of the circular shifted version of the delay value. Quantizing the delay value includes quantizing the circular shifted version of the delay value.

[0092] In some embodiments, the predetermined frequency range comprises the system bandwidth.

[0093] In some embodiments, after the first portion is transmitted, the second portion is transmitted to the network device.

[0094] 9 shows a flowchart of an example method 900 according to some other embodiments of the present disclosure. Method 900 may be implemented in terminal device 120 shown in FIG. 1. For purposes of discussion, method 900 will be described from the perspective of terminal device 120 with reference to FIG. 1.

[0095] In block 910, the terminal device 120 performs channel estimation between the terminal device and the network device over a predetermined frequency range for a set of beams having different spatial directions. In block 920, the terminal device 120 determines indication information based on the channel estimation. The indication information indicates at least one beam selected from a plurality of beams for a plurality of frequency locations within the predetermined frequency range. In block 930, the terminal device 120 transmits the indication information in a first portion of a channel state information (CSI) report to the network device.

[0096] In some embodiments, the indication information includes an index to define a codeword in a codebook configured for the CSI.

[0097] In some embodiments, the method further includes determining another indication based on the channel estimation and transmitting the indication in a second portion of the CSI report to the network equipment. The another indication indicates at least one of respective gains in the time domain for the at least one selected beam across a predetermined frequency range and respective co-phase shifts in the time domain for the at least one selected beam applied across the predetermined frequency range. After the first portion is transmitted, the second portion is transmitted to the network equipment.

[0098] 10 shows a flowchart of an example method 1000 according to some other embodiments of the present disclosure. Method 1000 may be implemented in network device 110 shown in FIG. 1. For discussion purposes, method 1000 will be described from the perspective of terminal device 120 with reference to FIG. 1.

[0099] In block 1010, the network device 110 receives a channel state information (CSI) report from the terminal device determined by channel estimation. A first portion of the CSI report includes at least first indication information indicating at least one beam from the beam set, and a second portion of the CSI report includes at least second indication information indicating multiple frequency locations for the selected at least one beam within a predetermined frequency range. In block 1020, the network device 110 generates CSI based on the first indication information and the second indication information to control transmission with the terminal device.

[0100] In some embodiments, the second indication includes at least one delay value in the time domain associated with the at least one selected beam, the delay value being applied across a predetermined frequency range. Creating the CSI includes determining frequency-related information for each selected beam by combining an associated delay value with a predetermined index of the plurality of frequency locations.

[0101] In some embodiments, the multiple frequency locations are configured by the network equipment.

[0102] In some embodiments, the second portion of the CSI report includes third and fourth indications, where the third indication indicates respective gains in the time domain for the at least one selected beam applied across a predetermined frequency range, and the fourth indication indicates respective co-phase shifts in the time domain for the at least one selected beam applied across the predetermined frequency range, and the method further includes determining respective gains for the at least one selected beam at the multiple frequency locations by weighting the second, third, and fourth indications.

[0103] In some embodiments, the first indication indicates a beam subset selected from the beam set, the beam subset including two or more beams, and the second portion of the CSI report further comprises fifth indication, the fifth indication indicating a gain of at least one beam in the beam subset at a subset of the plurality of frequency locations, such at least one beam being stronger than other beams in the beam subset.

[0104] In some embodiments, the second portion of the CSI report further comprises sixth indication information, the sixth indication information indicating a co-phase shift of each of the at least one beam in the beam subset at the at least one frequency location.

[0105] In some embodiments, the first portion of the CSI report further comprises another indication, the another indication indicating a channel quality indicator (CQI) corresponding to a frequency range or a plurality of frequency locations and respective CQIs corresponding thereto.

[0106] In some embodiments, generating the CSI includes determining a codeword from a codebook configured for the CSI based on the first indication information and the second indication information.

[0107] In some embodiments, the second portion is received by the network device after the first portion is received.

[0108] 11 shows a flowchart of an example method 1100 according to some further embodiments of the present disclosure. Method 1100 may be implemented in network device 110 shown in FIG. 1. For discussion purposes, method 1100 will be described from the perspective of terminal device 120 with reference to FIG. 1.

[0109] In block 1110, the network device 110 receives a channel state information (CSI) report from the terminal device determined by channel estimation. A first portion of the CSI report comprises at least indication information, the indication information indicating at least one beam selected from a plurality of beams for a plurality of frequency locations within a predetermined frequency range. In block 1220, the network device 110 generates CSI based on the first indication information and the second indication information to control transmission with the terminal device.

[0110] In some embodiments, the indication information includes an index for defining a codeword in a codebook configured for the CSI.

[0111] In some embodiments, the second portion of the CSI report further includes another indication, the another indication indicating at least one of a respective gain in the time domain for the at least one selected beam across a predetermined frequency range and a respective co-phase shift in the time domain for the at least one selected beam applied across the predetermined frequency range, the second portion being received by the network equipment after the first portion is received.

[0112] 12 is a schematic block diagram of a device 1200 suitable for implementing embodiments of the present disclosure. Device 1200 can be considered another example embodiment of network device 110 or terminal device 120 shown in FIG. 1. Thus, device 1200 can be implemented as or in at least a portion of network device 110 or terminal device 120,

[0113] As shown, device 1200 includes a processor 1210, a memory 1220 coupled to processor 1210, a suitable transmitter (TX) and receiver (RX) 1240 coupled to processor 1210, and a communication interface coupled to TX / RX 1240. Memory 1220 stores at least a portion of a program 1230. TX / RX 1240 is used for bidirectional communication. TX / RX 1240 has at least one antenna to facilitate communication; in practice, access nodes described herein may have multiple antennas. The communication interface may represent any interface required for communication with other network components, such as an X2 interface for bidirectional communication between eNBs, an S1 interface for communication between a Mobility Management Entity (MME) / Serving Gateway (S-GW) and eNBs, a Un interface for communication between an eNB and a Relay Node (RN), or a Uu interface for communication between an eNB and a terminal device.

[0114] Assuming that the program 1230 includes program instructions, these program instructions, when executed by the associated processor 1210, cause the device 1200 to operate according to the embodiments of the present disclosure as described herein with reference to Figures 2-4 and 9-12. The embodiments of the present disclosure may be implemented by computer software, hardware, or a combination of software and hardware executable by the processor 1210 of the device 1200. The processor 1210 may be configured to implement embodiments of the present disclosure. Furthermore, the combination of the processor 1210 and the memory 1220 may constitute a processing means 1250 suitable for implementing embodiments of the present disclosure.

[0115] Memory 1220 may be of any type suitable for a local technology network and may be implemented using any suitable data storage technology. Examples include, but are not limited to, non-transitory computer-readable storage media, semiconductor-based storage devices, magnetic storage devices and systems, optical storage devices and systems, fixed and removable memory, etc. Although only one memory 1220 is shown in device 1200, device 1200 may include multiple physically separated memory modules. Processor 1210 may be of any type suitable for a local technology network and may include, but is not limited to, one or more of a general-purpose computer, a special-purpose computer, a microprocessor, a digital signal processor (DSP), and a processor based on a multi-core processor configuration. Device 1200 may have multiple processors, such as application-specific integrated circuit chips time-slaved to a clock synchronized with a master processor.

[0116] Generally, embodiments of the present disclosure may be implemented using hardware or special-purpose circuits, software, logic, or any combination thereof. Some aspects may be implemented using hardware, while other aspects may be implemented using firmware or software executed by a controller, microprocessor, or other computing device. Although aspects of embodiments of the present disclosure have been shown and described as block diagrams, flow diagrams, or other graphical representations, it should be understood that the blocks, apparatus, systems, techniques, or methods described herein may be implemented using, for example, hardware, software, firmware, special-purpose circuits or logic, general-purpose hardware or controllers or other computing devices, or combinations thereof.

[0117] The present disclosure further provides at least one computer program product tangibly stored on a non-transitory computer-readable storage medium. The computer program product includes computer-executable instructions, e.g., those contained in program modules. The computer-executable instructions execute on a target real or virtual processor device to perform the processes or methods described above with reference to any of Figures 2-11. Typically, program modules include routines, programs, libraries, objects, classes, components, data structures, etc. that perform particular tasks or implement particular abstract data types. In various embodiments, the functionality of the program modules may be combined or split among program modules as desired. Device-executable instructions contained in program modules may be executed in local or distributed devices. In a distributed device, program modules may reside in both local and remote storage media.

[0118] Program code for carrying out the methods of the present disclosure can be written in any combination of one or more programming languages. The program code can be provided to a processor or controller of a general-purpose computer, a special-purpose computer, or other programmable data processing apparatus, and when executed by the processor or controller, the program code performs the functions / operations specified in the flow diagrams and / or block diagrams. The program code can run entirely on the device, partially on the device, as a separate software package, partially on the device and partially on a remote device, or entirely on a remote device or server.

[0119] The program code may be embodied on a device-readable medium, which may be any tangible medium that can contain or store a program provided for use by, or in connection with, an instruction execution system, apparatus, or device. The device-readable medium may be a device-readable signal medium or a device-readable storage medium. The device-readable medium may include, but is not limited to, an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any suitable combination of the foregoing. Further specific examples of device-readable storage media include one or more electrical connections, a portable computer diskette, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable optical disk read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the foregoing.

[0120] Although operations are described in a particular order, it should not be understood that the operations must be performed in the particular order shown, or in any sequential order, or that all of the operations shown must be performed to achieve desired results. In some situations, multiple tasks and parallel processing may be advantageous. Similarly, while the above description includes several specific implementation details, these should not be construed as limitations on the scope of the disclosure, but rather as descriptions of features that may be specific to particular embodiments. Some features described in the context of separate embodiments may also be implemented in combination in a single implementation. Conversely, various features described in the context of a single implementation may also be implemented separately in multiple implementations, or in any suitable subcombination.

[0121] Although the present disclosure has been described in language specifying structural features and / or method and operations, it is to be understood that the present disclosure, as defined by the appended claims, is not necessarily limited to the specific features or operations described above. Rather, the specific features and operations described above are disclosed as example forms of implementing the claims.

Claims

1. performing channel estimation between the terminal equipment and the network equipment over a predetermined frequency range for a set of beams having different spatial directions; determining first and second indication information based on the channel estimation; transmitting the first indication information in a first portion of a channel state information (CSI) report to the network device and transmitting the second indication information in a second portion of the CSI report to the network device; Equipped with A method implemented in a terminal device, wherein the first instruction information indicates at least one beam selected from the beam set, and the second instruction information indicates related information indicating multiple frequency positions for the selected at least one beam within the specified frequency range.

2. The method described in claim 1, wherein the related information for each selected beam is indicated by a combination of at least one delay value in the time domain of a channel path for each selected beam and a predetermined index of the multiple frequency positions.

3. The method of claim 1 , wherein the plurality of frequency locations are configured by the network equipment.

4. The method further comprises: determining third and fourth indication information based on the channel estimation; transmitting the third indication information and the fourth indication information in the second part of the CSI report to the network device; Equipped with the third indication indicates a respective gain in the time domain for the selected at least one beam to be applied across the predetermined frequency range; The method of claim 1 , wherein the fourth indication indicates respective co-phase shifts in the time domain for the selected at least one beam applied across the predetermined frequency range.

5. The first indication indicates a beam subset selected from the beam set, the beam subset comprising two or more beams, and the method further comprises: determining a fifth indication based on the channel estimation; and sending the fifth indication information in the second part of the CSI report to the network device; Equipped with The method of claim 1 , wherein the fifth indication indicates a gain of at least one beam in the beam subset at a subset of the plurality of frequency locations, the at least one beam being stronger than other beams in the beam subset.

6. The method further comprises: determining a sixth indication based on the channel estimation; and sending the sixth indication information in the second part of the CSI report to the network device; Equipped with The method of claim 5 , wherein the sixth indication indicates a co-phase shift of each of the at least one beam in the beam subset at the at least one frequency location.

7. the first portion of the CSI report further comprises further indication information; The method of claim 1 , wherein the further indication indicates a channel quality indicator (CQI) corresponding to the frequency range or each CQI corresponding to the plurality of frequency locations.

8. The transmitting, for each delay value of the at least one delay value, determining a first number of bits for quantizing the delay value based on the magnitude of the delay value; quantizing the delay value to the first number of bits; transmitting the first number of bits to the network device; Equipped with The method of claim 2 , wherein the first number is greater than a number of bits determined for another delay value having a smaller magnitude.

9. The transmitting, for each beam of the at least one beam, determining a second number of bits for quantizing the delay values ​​based on a gain of the selected at least one beam; quantizing the delay value to the second number of bits; transmitting the second number of bits to the network device; Equipped with The method of claim 2 , wherein the second number is greater than a number of bits determined for another delay value corresponding to another beam having a higher gain.

10. Determining the second number of bits includes: modifying the delay value by shifting the delay value by one circular shift value to obtain a circularly shifted version of the delay value; determining the second number of bits based on the gain of the circularly shifted version of the delay value; and Equipped with The method of claim 9 , wherein quantizing the delay value comprises quantizing the circularly shifted version of the delay value.

11. The method of claim 1 , wherein the predetermined frequency range comprises a system bandwidth.

12. The method of claim 1 , wherein the second portion is transmitted to the network device after the first portion is transmitted.

13. performing channel estimation between the terminal equipment and the network equipment over a predetermined frequency range for a set of beams having different spatial directions; determining an indication based on the channel estimate; and transmitting the indication information in a first portion of a channel state information (CSI) report to the network device; Equipped with A method implemented in a terminal device, wherein the indication information indicates at least one beam selected from a plurality of beams for a plurality of frequency locations within the predetermined frequency range.

14. The method of claim 13 , wherein the indication information comprises an index for defining a codeword in a codebook configured for the CSI.

15. The method further comprises: determining a further indication based on the channel estimate; and transmitting the other indication information in a second portion of the CSI report to the network device; Equipped with the further indication indicates at least one of a respective gain in the time domain for the selected at least one beam applied across the predetermined frequency range and a respective co-phase shift in the time domain for the selected at least one beam applied across the predetermined frequency range; The method of claim 13 , wherein the second portion is transmitted to the network device after the first portion is transmitted.

16. receiving, from a terminal device, a channel state information (CSI) report determined by the channel estimation; generating CSI based on the first instruction information and the second instruction information to control transmission with the terminal device; Equipped with the first portion of the CSI report comprises at least the first indication information indicating at least one beam of a beam set; A method implemented in a network equipment, wherein the second portion of the CSI report comprises at least the second indication information, the second indication information indicating a plurality of frequency locations for the at least one selected beam within a predetermined frequency range.

17. the second indication comprises at least one delay value in the time domain of a channel path for each selected beam; the at least one delay value is applied across the predetermined frequency range; Creating the CSI includes:

17. The method of claim 16, comprising determining relevant information for each selected beam by a combination of at least one delay value in the time domain of a channel path for each selected beam and a predetermined index of the plurality of frequency locations.

18. the first indication indicates a beam subset selected from the beam set, the beam subset comprising two or more beams; the second portion of the CSI report further comprises fifth indication, the fifth indication indicating a gain of at least one beam in the beam subset at the subset of the plurality of frequency locations, the at least one beam being stronger than other beams in the beam subset; the second portion of the CSI report further comprises sixth indication information; the sixth indication indicates a co-phase shift of each of the at least one beam in the beam subset at the at least one frequency location; the first portion of the CSI report further comprises further indication information; The method of claim 16 , wherein the further indication indicates a channel quality indicator (CQI) corresponding to the frequency range or each CQI corresponding to the plurality of frequency locations.

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