Wireless communication method and related apparatus

Abstract

Provided are a wireless communication method and related apparatus. The method includes: receiving first information, where the first information is used for determining first frequency resource units for carrying at least one first sequence in a first frequency resource, and a reference signal corresponding to the at least one first sequence is used for measuring a channel over the first frequency resource; where the first frequency resource units in the first frequency resource are determined based on interleaving of second frequency resource units, and the second frequency resource units belong to the first frequency resource. The interleaving ensures random-like properties of the first frequency resource units required for compressed sensing algorithms, in other words, reference signals carried on the first frequency resource can be in random-like positioning, it makes compressed sensing algorithms applicable for estimating channel over the first frequency resource, thus less resource elements are used for the channel estimation, i.e., channel estimation overhead can be reduced, and more resource elements can be left for other uses.

Description

WIRELESS COMMUNICATION METHOD AND RELATED APPARATUSTECHNICAL FIELD

[0001] The present application relates to the field of communication technologies, and in particular, to a wireless communication method and related apparatus.BACKGROUND

[0002] In multiple-input multiple-output (MIMO) systems, a device, for example, a network device or a terminal, can perform channel estimation based on reference signals, and then restore data signals transmitted through data channels based on the channel estimation. Therefore, reference signal allocation is essential for MIMO systems.

[0003] The amount of resources in time and frequency required for the channel estimation is called channel estimation overhead (or simply overhead). The overhead is measured in resource elements (REs). There is a tradeoff between accuracy and overhead of the channel estimation. Too high overhead will yield good channel estimation, but few REs will be left for data transmission, thus the capacity will be low. Too small overhead will leave a lot of REs for data transmission, but the channel estimation will be poor, thus again leading to low capacity.

[0004] This background information is provided to reveal information believed by the applicant to be of possible relevance to the present application. No admission is necessarily intended, nor should be construed, that any of the preceding information constitutes prior art against the present application.SUMMARY

[0005] In a first aspect, a wireless communication method is provided by the present disclosure, and the method comprises: receiving first information, where the first information is used for determining first frequency resource units for carrying at least one first sequence in a first frequency resource, anda reference signal corresponding to the at least one first sequence is used for measuring a channel over the first frequency resource; where the first frequency resource units in the first frequency resource are determined based on interleaving of second frequency resource units, and the second frequency resource units belong to the first frequency resource.

[0006] The first frequency resource units are determined based on interleaving of the second frequency resource units, the interleaving ensures random-like properties of the first frequency resource units required for compressed sensing algorithms, in other words, reference signals carried on the first frequency resource can be allocated in a quasi-random manner, it makes compressed sensing algorithms applicable for estimating a channel over the first frequency resource, thus less resource elements are used for the channel estimation, i.e., channel estimation overhead can be reduced, and more resource elements can be left for other uses.

[0007] The wireless communication method may be applied to a first network element, and the first network element may be a terminal device, a communications module in a terminal, or a circuit or a chip (for example, a modem (Modem) chip, also referred to as a baseband (baseband) chip, or a system on chip (System on Chip) including a modem core) that is responsible for a communication function and that is in a terminal; SoC) chip or system in package (SIP) chip .

[0008] In a possible implementation of the first aspect, at least one parameter of the interleaving is associated with a total number of resource elements (REs) comprised in the first frequency resource.

[0009] When the total number of REs varies, the parameter(s) associated with the interleaving may vary accordingly. When choosing the parameter(s) associated with the interleaving, the total number of the resource elements included in the first frequency resource needs to be taken into account.

[0010] In a possible implementation of the first aspect, positions of the second frequency resource units are associated with a type of the interleaving.

[0011] The positions of the second frequency resource units may vary based on the type of the interleaving, i.e., a pattern of frequency resource units before interleaving can be different if different types of the interleaving are adopted.

[0012] In a possible implementation of the first aspect, the interleaving comprises appliance ofat least one of a cubic permutation polynomial (CPP) interleaver, a quadratic permutation polynomial (QPP) interleaver, a Takeshita-Costello interleaver, a Welch-Costas interleaver, an interleaver based on a pseudo-noise (PN) sequence or an interleaver based on a random integer sequence.

[0013] The interleaving can be performed by means of a CPP interleaver, a QPP interleaver, a Takeshita-Costello interleaver, a Welch-Costas interleaver, an interleaver based on a PN sequence or an interleaver based on a random integer sequence, or a combination of two or more of the foregoing mentioned interleavers. It provides flexibility for the foregoing mentioned interleaving, thus the interleaving strategy can be designed according to actual needs.

[0014] In a possible implementation of the first aspect, the interleaving comprises appliance of the QPP interleaver; where the interleaving is based on a first coefficient and a second coefficient, the first coefficient and the second coefficient are used for determining a sampling pattern of all frequency resource units in the first frequency resource.

[0015] In a possible implementation of the first aspect, the first coefficient and the second coefficient are used for obtaining a one-to-one correspondence between positions of the second frequency resource units and positions of the first frequency resource units.

[0016] For example, a sampling pattern of all frequency resource units in the first frequency resource may refer to a pattern with positions of reference signals for channel estimation being 1 and other positions being 0, since the transmission of the reference signals on the first frequency resource units would be like sampling of the channel over the first frequency resource. By setting appropriate first and second coefficients, the positions of the second frequency resource units and the positions of the first frequency resource units are in one-to-one correspondence, the positions of the first frequency resource units can be allocated in a quasi-random manner. In addition, the first coefficient and the second coefficient can be chosen in such a way that the signal recovery properties with CS algorithms will be improved.

[0017] In a possible implementation of the first aspect, a first factorization of the first coefficient is represented as a product of multiple first integers and an interleaving factor, where the interleaving factor is an integer not divisible by any one of the multiple first integers, and each of the multiple first integers is a prime number.

[0018] In a possible implementation of the first aspect, a second factorization of a total numberof resource elements in the first frequency resource is represented as a product of the multiple first integers with multiple first powers corresponding to the multiple first integers respectively, and at least one of the first powers is greater than one; where the second coefficient is not divisible by any one of the multiple first integers.

[0019] In a possible implementation of the first aspect, the first coefficient and the second coefficient are predefined, or the first information indicates the first coefficient and the second coefficient.

[0020] The first coefficient and the second coefficient can be predefined for a first network element, or can be obtained by a first network element from a second network element, for example, the second network element directly transmits or indirectly indicates the first coefficient and the second coefficient to the first network element, thereby improving flexibility of obtaining the coefficients.

[0021] In a possible implementation of the first aspect, the first coefficient and the second coefficient are determined based on a table.

[0022] In a case that a first network element stores a table, and the table represents a correspondence between an index and the coefficients, the first network element can easily obtain target first and second coefficients via a target index indicated by a second network element according to the correspondence. In this way, signaling can be saved.

[0023] In a possible implementation of the first aspect, at least one first frequency resource unit of the first frequency resource units includes multiple resource elements; a position of a third frequency resource unit on a second frequency resource is determined based on the QPP interleaver and a position of the at least one first frequency resource unit, where the second frequency resource and the first frequency resource are on different symbols, and the third frequency resource unit is used for carrying at least one second sequence.

[0024] In a case that a second frequency resource unit includes multiple resource elements, it means that the interleaving can be performed at a block level (block- wise), and frequency hopping can be performed in such case. A hopping position of the third frequency resource unit after frequency hopping depends on a position of the above at least one first frequency resource unit, so the at least one first frequency resource unit is taken as a frequency resource unit before interleaving, and the third frequency resource unit is taken as a frequency resource unit afterinterleaving, in this way, the position of the third frequency resource unit can thus be obtained by inputting the position of the at least one first frequency resource unit into the QPP interleaver. The position of the frequency resource unit after frequency hopping is associated with the starting position of the frequency resource unit and the QPP interleaver. Instead of covering all available frequency resource units in the normal frequency hopping, some frequency resource units can be skipped in the above described frequency hopping by virtue of the QPP interleaver design, thereby reducing the channel estimation overhead.

[0025] In a possible implementation of the first aspect, the interleaving comprises appliance of the interleaver based on the PN sequence, the total number of resource elements in the first frequency resource is equal to a power of two.

[0026] In a possible implementation of the first aspect, the first information further indicates the second frequency resource units.

[0027] In this way, a first network element may obtain the second frequency resource units before the interleaving, and directly perform the interleaving based on a predefined rule to obtain the first frequency resource units. In this case, it is not necessary for the second network element to transmit the first frequency resource units after the interleaving to the first network element.

[0028] In a possible implementation of the first aspect, the first information comprises a bitmap for indicating the second frequency resource units.

[0029] In a possible implementation of the first aspect, at least one of first frequency resource units comprises multiple resource elements, or, each of the first frequency resource units comprises one resource element.

[0030] The interleaving can be performed at a block level (block-wise), where a block includes multiple resource elements; and can also be performed at a resource element level (element- wise).

[0031] In a possible implementation of the first aspect, the method further comprises: transmitting the at least one first sequence over the first frequency resource.

[0032] A first network element transmits the at least one first sequence to a second network element, thus reference signals corresponding to the at least one first sequence can be used for uplink channel estimation.

[0033] In a possible implementation of the first aspect, the reference signal corresponding to the at least one first sequence is a sounding reference signal (SRS) or a demodulation reference signal(DMRS).

[0034] In a possible implementation of the first aspect, the method further comprises: receiving the at least one first sequence over the first frequency resource, where the reference signal corresponding to the at least one first sequence is a channel state information reference signal (CSI-RS).

[0035] A first network element receives the at least one first sequence from a second network element, and reference signals corresponding to the at least one first sequence can be used for downlink channel estimation.

[0036] In a possible implementation of the first aspect, the first information is carried in at least one of MAC control element (MAC CE), downlink control information (DCI) or radio resource control (RRC).

[0037] In a possible implementation of the first aspect, the method further comprises: receiving second information, where the second information is used for determining fourth frequency resource units for carrying at least one third sequence in a third frequency resource, and a reference signal corresponding to the at least one third sequence is used for measuring a channel over the third frequency resource; where the first frequency resource units and the fourth frequency resource units are non-overlapping in a frequency domain.

[0038] There can be more than one antenna to transmit or receive reference signals with nonoverlapping frequency resource units, and the process of transmitting or receiving reference signals for each antenna is similar.

[0039] In a second aspect, a wireless communication method is provided by the present disclosure, and the method comprises: transmitting first information, where the first information is used for determining first frequency resource units for carrying at least one first sequence in a first frequency resource, and a reference signal corresponding to the at least one first sequence is used for measuring a channel over the first frequency resource; where the first frequency resource units in the first frequency resource are determined based on interleaving of second frequency resource units, and the second frequency resource units belong to the first frequency resource.

[0040] The first frequency resource units are determined based on interleaving of the second frequency resource units, the interleaving ensures random-like properties of the first frequency resource units required for compressed sensing (CS) algorithms, in other words, reference signals carried on the first frequency resource can be allocated in such a quasi-random manner that it makes compressed sensing algorithms applicable for estimating a channel over the first frequency resource, thus less resource elements are used for the channel estimation, i.e., channel estimation overhead can be reduced, and more resource elements can be left for other uses.

[0041] The wireless communication method may be applied to a second network element, and the second network element may be a network device, or a component (for example, a circuit, a chip, or a chip system) in a network device.

[0042] In a possible implementation of the second aspect, at least one parameter of the interleaving is associated with a total number of resource elements (REs) included in the first frequency resource.

[0043] When the total number of REs varies, the parameter(s) associated with the interleaving may vary accordingly. When choosing the parameter(s) associated with the interleaving, the total number of the resource elements included in the first frequency resource needs to be taken into account.

[0044] In a possible implementation of the second aspect, positions of the second frequency resource units are associated with a type of the interleaving.

[0045] The positions of the second frequency resource units may vary based on the type of the interleaving, i.e., a pattern of frequency resource units before interleaving can be different if different types of the interleaving are adopted.

[0046] In a possible implementation of the second aspect, the interleaving comprises appliance of at least one of a cubic permutation polynomial (CPP) interleaver, a quadratic permutation polynomial (QPP) interleaver, a Takeshita-Costello interleaver, a Welch-Costas interleaver, an interleaver based on a pseudo-noise (PN) sequence or an interleaver based on a random integer sequence.

[0047] The interleaving can be performed by means of a CPP interleaver, a QPP interleaver, a Takeshita-Costello interleaver, a Welch-Costas interleaver, an interleaver based on a PN sequence or an interleaver based on a random integer sequence, or a combination of two or more of theforegoing mentioned interleavers. It provides flexibility for the foregoing mentioned interleaving, thus the interleaving strategy can be designed according to actual requirements.

[0048] In a possible implementation of the second aspect, the interleaving comprises appliance of the QPP interleaver; where the interleaving is based on a first coefficient and a second coefficient, the first coefficient and the second coefficient are used for determining a sampling pattern of all frequency resource units in the first frequency resource.

[0049] In a possible implementation of the second aspect, the first coefficient and the second coefficient are used for obtaining a one-to-one correspondence between positions of the second frequency resource units and positions of the first frequency resource units.

[0050] By setting appropriate first and second coefficients, the positions of the second frequency resource units and the positions of the first frequency resource units are in one-to-one correspondence, the positions of the first frequency resource units can be allocated in a quasirandom manner. In addition, the first coefficient and the second coefficient can be chosen in such a way that the signal recovery properties with CS algorithms will be improved.

[0051] In a possible implementation of the second aspect, a first factorization of the first coefficient is represented as a product of multiple first integers and an interleaving factor, where the interleaving factor is an integer not divisible by any one of the multiple first integers, and each of the multiple first integers is a prime number.

[0052] In a possible implementation of the second aspect, a second factorization of a total number of resource elements in the first frequency resource is represented as a product of the multiple first integers with multiple first powers corresponding to the multiple first integers respectively, and at least one of the first powers is greater than one; wherein the second coefficient is not divisible by any one of the multiple first integers.

[0053] In a possible implementation of the second aspect, the first coefficient and the second coefficient are predefined, or, the first information indicates the first coefficient and the second coefficient.

[0054] The first coefficient and the second coefficient can be predefined for a first network element, or can be transmitted to a first network element from a second network element, for example, the second network element directly transmits or indirectly indicates the first coefficient and the second coefficient to the first network element, thereby improving flexibility of obtainingthe coefficients.

[0055] In a possible implementation of the second aspect, the first coefficient and the second coefficient are determined based on a table.

[0056] In a case that a first network element stores a table, and the table represents a correspondence between an index and the coefficients, the first network element can easily obtain target first and second coefficients via a target index indicated by a second network element. In this way, signaling can be saved.

[0057] In a possible implementation of the second aspect, at least one first frequency resource unit of the first frequency resource units includes multiple resource elements; a position of a third frequency resource unit on a second frequency resource is determined based on the QPP interleaver and a position of the at least one first frequency resource unit, where the second frequency resource and the first frequency resource are on different symbols, and the third frequency resource unit is used for carrying at least one second sequence.

[0058] In a case that a second frequency resource unit includes multiple resource elements, it means that the interleaving can be performed at a block level, and frequency hopping can be performed in such case. A hopping position of the third frequency resource unit after frequency hopping depends on a position of the above at least one first frequency resource unit, so the at least one first frequency resource unit is taken as a frequency resource unit before interleaving, and the third frequency resource unit is taken as a frequency resource unit after interleaving, in this way, the position of the third frequency resource unit can thus be obtained by inputting the position of the at least one first frequency resource unit into the QPP interleaver. The position of the frequency resource unit after frequency hopping is associated with the starting position of the frequency resource unit and the QPP interleaver. Instead of covering all available frequency resource units in the normal frequency hopping, some frequency resource units can be skipped in the above described frequency hopping by virtue of the QPP interleaver design, thereby reducing the channel estimation overhead.

[0059] In a possible implementation of the second aspect, the interleaving comprises appliance of the interleaver based on the PN sequence, the total number of resource elements in the first frequency resource is equal to a power of two.

[0060] In a possible implementation of the second aspect, the first information further indicatesthe second frequency resource units.

[0061] A second network element may indicate the second frequency resource units before the interleaving to a first network element, so that the first network element can directly perform the interleaving based on a predefined rule to obtain the first frequency resource units. In this case, it is not necessary for the second network element to indicate the first frequency resource units after the interleaving to the first network element.

[0062] In a possible implementation of the second aspect, the first information comprises a bitmap for indicating the second frequency resource units.

[0063] In a possible implementation of the second aspect, at least one of first frequency resource units includes multiple resource elements, or, each of the first frequency resource units includes one resource element.

[0064] The interleaving can be performed at a block level, where a block includes multiple resource elements; and can also be performed at a resource element level.

[0065] In a possible implementation of the second aspect, the method further comprises: receiving the at least one first sequence over the first frequency resource.

[0066] A second network element receives the at least one first sequence from a first network element, thus reference signals corresponding to the at least one first sequence can be used for uplink channel estimation.

[0067] In a possible implementation of the second aspect, the reference signal corresponding to the at least one first sequence is a sounding reference signal (SRS) or a demodulation reference signal (DMRS).

[0068] In a possible implementation of the second aspect, the method further comprises: transmitting the at least one first sequence over the first frequency resource, where the reference signal corresponding to the at least one first sequence is a channel state information reference signal (CSI-RS).

[0069] A second network element transmits the at least one first sequence to a first network element, and reference signals corresponding to the at least one first sequence can be used for downlink channel estimation.

[0070] In a possible implementation of the second aspect, the first information is carried in at least one of MAC control element (MAC CE), downlink control information (DCI) or radio ioresource control (RRC).

[0071] In a possible implementation of the second aspect, the method further comprises: transmitting second information, where the second information is used for determining fourth frequency resource units for carrying at least one third sequence in a third frequency resource, and a reference signal corresponding to the at least one third sequence is used for measuring a channel over the third frequency resource; where the first frequency resource units and the fourth frequency resource units are non-overlapping in a frequency domain.

[0072] There can be more than one antenna to transmit or receive reference signals with nonoverlapping frequency resource units, and the process of transmitting or receiving reference signals for each antenna is similar.

[0073] In a third aspect, a wireless communication apparatus is provided by the present disclosure, and the apparatus includes various modules configured to execute the wireless communication method according to the first aspect or any possible implementation of the first aspect.

[0074] In a fourth aspect, a wireless communication apparatus is provided by the present disclosure, and the apparatus includes various modules configured to execute the wireless communication method according to the second aspect or any possible implementation of the second aspect.

[0075] In a fifth aspect, a wireless communication apparatus is provided by the present disclosure, and the apparatus includes at least one processor, where the at least one processor is configured to execute the wireless communication method according to the first aspect or any possible implementation of the first aspect or according to the second aspect or any possible implementation of the second aspect.

[0076] In a possible implementation of the fifth aspect, the above apparatus may further include a memory, and the memory stores instructions that cause the at least one processor to execute the wireless communication method according to the first aspect or any possible implementation of the first aspect or according to the second aspect or any possible implementation of the second aspect.

[0077] In a sixth aspect, a wireless communication apparatus is provided by the presentdisclosure, and the apparatus is configured to execute the wireless communication method according to the first aspect or any possible implementation of the first aspect or according to the second aspect or any possible implementation of the second aspect.

[0078] In a seventh aspect, a first network element is provided by the present disclosure, and the first network element includes processing circuitry for executing the wireless communication method according to the first aspect or any possible implementation of the first aspect.

[0079] In an eighth aspect, a second network element is provided by the present disclosure, and the second network element includes processing circuitry for executing the wireless communication method according to the second aspect or any possible implementation of the second aspect.

[0080] In a ninth aspect, a wireless communication system is provided by the present disclosure, and the wireless communication system includes the first network element according to the seventh aspect and the second network element according to the eighth aspect.

[0081] In a tenth aspect, a chip is provided by the present disclosure, and the chip includes an input / output (I / O) interface and a processor, where the processor is configured to call and run computer execution instructions stored in a memory, to enable a device installing with the chip to execute the wireless communication method according to the first aspect or any possible implementation of the first aspect or according to the second aspect or any possible implementation of the second aspect.

[0082] In an eleventh aspect, a computer-readable medium is provided by the present disclosure, and the computer-readable medium includes storing computer execution instructions which, when executed by a processor, causes the processor to execute the wireless communication method according to the first aspect or any possible implementation of the first aspect or according to the second aspect or any possible implementation of the second aspect.

[0083] In a twelfth aspect, a computer program product is provided by the present disclosure, and the computer program product includes computer execution instructions which, when executed by a processor, causes the processor to execute the wireless communication method according to the first aspect or any possible implementation of the first aspect or according to the second aspect or any possible implementation of the second aspect.

[0084] A wireless communication method and related apparatus are provided by the presentdisclosure. A second network element transmits first information to a first network element, where the first information is used for determining first frequency resource units for carrying at least one first sequence in a first frequency resource, and a reference signal corresponding to the at least one first sequence is used for measuring a channel over the first frequency resource, where the first frequency resource units in the first frequency resource are determined based on interleaving of second frequency resource units, and the second frequency resource units belong to the first frequency resource. The interleaving ensures random-like properties of the first frequency resource units required for compressed sensing algorithms, in other words, reference signals carried on the first frequency resource can be allocated in a quasi-random manner, it makes compressed sensing algorithms applicable for estimating a channel over the first frequency resource, thus less resource elements are used for the channel estimation, i.e., channel estimation overhead can be reduced, and more resource elements can be left for other uses.BRIEF DESCRIPTION OF DRAWINGS

[0085] The accompanying drawings are used to provide a further understanding of the present disclosure, constitute a part of the specification, and are used to explain the present disclosure together with the following specific embodiments, but should not be construed as limiting the present disclosure.

[0086] FIG. 1 is a schematic illustration of a communication system according to one or more embodiments of the present disclosure.

[0087] FIG. 2 is another schematic illustration of a communication system according to one or more embodiments of the present disclosure.

[0088] FIG. 3 is a schematic illustration of basic component structure of a communication system according to one or more embodiments of the present disclosure.

[0089] FIG. 4 illustrates a block diagram of a device in a communication system according to one or more embodiments of the present disclosure.

[0090] FIG. 5 is a schematic illustration of effects of comb-like structure reference signal allocation on channel impulse response (CIR) of one antenna according to one or more embodiments of the present disclosure.

[0091] FIG. 6 is a schematic illustration of channel estimation of several antennas based on measurements on the same subcarriers according to one or more embodiments of the present disclosure.

[0092] FIG. 7 is a schematic illustration of extracting single antenna CIR from cyclically shifted CIRs and obtaining the frequency domain channel estimation according to one or more embodiments of the present disclosure.

[0093] FIG. 8 is a schematic illustration of effects of comb-8 sampling in the frequency domain with aliasing according to one or more embodiments of the present disclosure.

[0094] FIG. 9 is a schematic illustration of effects of aliasing for channels sampled with comb-4 and separated by cyclic shift being 2 according to one or more embodiments of the present disclosure.

[0095] FIG. 10 is a schematic illustration of impact of aliasing on the quality of channel estimation according to one or more embodiments of the present disclosure.

[0096] FIG. 11 is a schematic illustration of uniformly random sampling pattern and the corresponding sampling effect according to one or more embodiments of the present disclosure.

[0097] FIG. 12 is a schematic illustration of another sampling pattern and the corresponding sampling effect according to one or more embodiments of the present disclosure.

[0098] FIG. 13 is a flowchart of a wireless communication method according to an embodiment of the present disclosure.

[0099] FIG. 14 is a schematic illustration of a sequence generating by an interleaver based on a PN-sequence according to one or more embodiments of the present disclosure.

[0100] FIG. 15 is a flowchart of another wireless communication method according to an embodiment of the present disclosure.

[0101] FIG. 16a is a schematic illustration of a resource unit configuration according to one or more embodiments of the present disclosure.

[0102] FIG. 16b is a schematic illustration of another resource unit configuration according to one or more embodiments of the present disclosure.

[0103] FIG. 16c is a schematic illustration of still another resource unit configuration according to one or more embodiments of the present disclosure.

[0104] FIG. 17 is a schematic illustration of generating a quasi-random sampling patternelement-wise according to one or more embodiments of the present disclosure.

[0105] FIG. 18A is a schematic illustration of generating a quasi-random sampling pattern blockwise according to one or more embodiments of the present disclosure.

[0106] FIG. 18B is a schematic illustration of a frequency hopping scheme according to one or more embodiments of the present disclosure.

[0107] FIG. 18C is a schematic illustration of another frequency hopping scheme according to one or more embodiments of the present disclosure.

[0108] FIG. 19A is a schematic illustration of channel estimation using compressed sensing algorithms according to one or more embodiments of the present disclosure.

[0109] FIG. 19B is a schematic illustration of the relationship between mutual coherence and sidelobe according to one or more embodiments of the present disclosure.

[0110] FIG. 20 is a block diagram of a wireless communication apparatus according to one or more embodiments of the present disclosure.

[0111] FIG. 21 is a block diagram of another wireless communication apparatus according to one or more embodiments of the present disclosure.

[0112] FIG. 22 is a schematic structural diagram of a wireless communication apparatus according to one or more embodiments of the present disclosure.DESCRIPTION OF EMBODIMENTS

[0113] In the following description, reference is made to the accompanying figures, which form part of the present disclosure, and which show, by way of illustration, specific aspects of embodiments of the present disclosure or specific aspects in which embodiments of the present disclosure may be used. It is understood that embodiments of the present disclosure may be used in other aspects and include structural or logical changes not depicted in the figures. The following detailed description, therefore, is not to be taken in a limiting sense, and the scope of the present disclosure is defined by the appended claims.

[0114] To assist in understanding the present disclosure, examples of wireless communication systems and devices are described below.

[0115] Example communication systems and devices

[0116] Referring to FIG. 1, as an illustrative example without limitation, a simplified schematic illustration of a communication system is provided. The communication system 100 includes a radio access network 120. The radio access network 120 may be a next generation (e.g., sixth generation (6G) or later) radio access network, or a legacy (e.g., 5G, 4G, 3G or 2G) radio access network. One or more communication electric device (ED) HOa-llOj (generically referred to as 110) may be interconnected to one another or connected to one or more network nodes (170a, 170b, generically referred to as 170) in the radio access network 120. A core network 130 may be a part of the communication system and may be dependent or independent of the radio access technology used in the communication system 100. Also, the communication system 100 includes a public switched telephone network (PSTN) 140, the internet 150, and other networks 160.

[0117] FIG. 2 illustrates an example communication system 100. In general, the communication system 100 enables multiple wireless or wired elements to communicate data and other content. The purpose of the communication system 100 may be to provide content, such as voice, data, video, and / or text, via broadcast, multicast and unicast, etc. The communication system 100 may operate by sharing resources, such as carrier spectrum bandwidth, between its constituent elements. The communication system 100 may include a terrestrial communication system and / or a nonterrestrial communication system. The communication system 100 may provide a wide range of communication services and applications (such as earth monitoring, remote sensing, passive sensing and positioning, navigation and tracking, autonomous delivery and mobility, etc.). The communication system 100 may provide a high degree of availability and robustness through a joint operation of the terrestrial communication system and the non-terrestrial communication system. For example, integrating a non-terrestrial communication system (or components thereof) into a terrestrial communication system can result in what may be considered a heterogeneous network including multiple layers. Compared to conventional communication networks, the heterogeneous network may achieve better overall performance through efficient multi-link joint operation, more flexible functionality sharing, and faster physical layer link switching between terrestrial networks and non-terrestrial networks.

[0118] The terrestrial communication system and the non-terrestrial communication system could be considered sub-systems of the communication system. In the example shown, the communication system 100 includes electronic devices (ED) 110a-l lOd (generically referred to asED 110), radio access networks (RANs) 120a- 120b, non-terrestrial communication network 120c, a core network 130, a public switched telephone network (PSTN) 140, the internet 150, and other networks 160. The RANs 120a-120b include respective base stations (BSs) 170a-170b, which may be generically referred to as terrestrial transmit and receive points (T-TRPs) 170a- 170b. The nonterrestrial communication network 120c includes an access node 120c, which may be generically referred to as a non-terrestrial transmit and receive point (NT-TRP) 172.

[0119] Any ED 110 may be alternatively or additionally configured to interface, access, or communicate with any other T-TRP 170a-170b and NT-TRP 172, the internet 150, the core network 130, the PSTN 140, the other networks 160, or any combination of the preceding. In some examples, ED 110a may communicate an uplink and / or downlink transmission over an interface 190a with T-TRP 170a. In some examples, the EDs 110a, 110b, 110c and l lOd may also communicate directly with one another via one or more sidelink air interfaces 190b. In some examples, ED 11 Od may communicate an uplink and / or downlink transmission over an interface 190c with NT-TRP 172.

[0120] The air interfaces 190a and 190b may use similar communication technology, such as any suitable radio access technology. For example, the communication system 100 may implement one or more channel access methods, such as code division multiple access (CDMA), time division multiple access (TDMA), frequency division multiple access (FDMA), orthogonal FDMA (OFDMA), or single-carrier FDMA (SC-FDMA) in the air interfaces 190a and 190b. The air interfaces 190a and 190b may utilize other higher dimension signal spaces, which may involve a combination of orthogonal and / or non-orthogonal dimensions.

[0121] The air interface 190c can enable communication between the ED llOd and one or multiple NT-TRPs 172 via a wireless link or simply a link. In some examples, the link is a dedicated connection for unicast transmission, a connection for broadcast transmission, or a connection between a group of EDs and one or multiple NT-TRPs for multicast transmission.

[0122] The RANs 120a and 120b are in communication with the core network 130 to provide the EDs 110a 110b, and 110c with various services such as voice, data, and other services. The RANs 120a and 120b and / or the core network 130 may be in direct or indirect communication with one or more other RANs (not shown), which may or may not be directly served by core network 130, and may or may not employ the same radio access technology as RAN 120a, RAN 120b or both.The core network 130 may also serve as a gateway access between (i) the RANs 120a and 120b or EDs 110a 110b, and 110c or both, and (ii) other networks (such as the PSTN 140, the internet 150, and the other networks 160). In addition, some or all of the EDs 110a 110b, and 110c may include functionality for communicating with different wireless networks over different wireless links using different wireless technologies and / or protocols. Instead of wireless communication (or in addition thereto), the EDs 110a 110b, and 110c may communicate via wired communication channels to a service provider or switch (not shown), and to the internet 150. PSTN 140 may include circuit switched telephone networks for providing plain old telephone service (POTS). Internet 150 may include a network of computers and subnets (intranets) or both, and incorporate protocols, such as Internet Protocol (IP), Transmission Control Protocol (TCP), User Datagram Protocol (UDP). EDs 110a 110b, and 110c may be multimode devices capable of operation according to multiple radio access technologies, and incorporate multiple transceivers necessary to support such.

[0123] Basic component structure

[0124] FIG. 3 illustrates another example of an ED 110 and a base station 170a, 170b and / or 170c. The ED 110 is used to connect persons, objects, machines, etc. The ED 110 may be widely used in various scenarios, for example, cellular communications, device-to-device (D2D), vehicle to everything (V2X), peer-to-peer (P2P), machine-to-machine (M2M), machine-type communications (MTC), internet of things (IOT), virtual reality (VR), augmented reality (AR), industrial control, self-driving, remote medical, smart grid, smart furniture, smart office, smart wearable, smart transportation, smart city, drones, robots, remote sensing, passive sensing, positioning, navigation and tracking, autonomous delivery and mobility, etc.

[0125] Each ED 110 represents any suitable end user device for wireless operation and may include such devices (or may be referred to) as a user equipment / device (UE), a wireless transmit / receive unit (WTRU), a mobile station, a fixed or mobile subscriber unit, a cellular telephone, a station (STA), a machine type communication (MTC) device, a personal digital assistant (PDA), a smartphone, a laptop, a computer, a tablet, a wireless sensor, a consumer electronics device, a smart book, a vehicle, a car, a truck, a bus, a train, or an loT device, an industrial device, or apparatus (e.g. communication module, modem, or chip) in the forgoing devices, among other possibilities. Future generation EDs 110 may be referred to using other terms.The base station 170a and 170b is a T-TRP and will hereafter be referred to as T-TRP 170. Also shown in FIG. 3, a NT-TRP will hereafter be referred to as NT-TRP 172. Each ED 110 connected to T-TRP 170 and / or NT-TRP 172 can be dynamically or semi-statically tumed-on (i.e., established, activated, or enabled), turned-off (i.e., released, deactivated, or disabled) and / or configured in response to one of more of: connection availability and connection necessity.

[0126] The ED 110 includes a transmitter 201 and a receiver 203 coupled to one or more antennas 204. Only one antenna 204 is illustrated. One, some, or all of the antennas may alternatively be panels. The transmitter 201 and the receiver 203 may be integrated, e.g. as a transceiver. The transceiver is configured to modulate data or other content for transmission by at least one antenna 204 or network interface controller (NIC). The transceiver is also configured to demodulate data or other content received by the at least one antenna 204. Each transceiver includes any suitable structure for generating signals for wireless or wired transmission and / or processing signals received wirelessly or by wire. Each antenna 204 includes any suitable structure for transmitting and / or receiving wireless or wired signals.

[0127] The ED 110 includes at least one memory 208. The memory 208 stores instructions and data used, generated, or collected by the ED 110. For example, the memory 208 could store software instructions or modules configured to implement some or all of the functionality and / or embodiments described herein and that are executed by the processing unit(s) 210. Each memory 208 includes any suitable volatile and / or non-volatile storage and retrieval device(s). Any suitable type of memory may be used, such as random access memory (RAM), read only memory (ROM), hard disk, optical disc, subscriber identity module (SIM) card, memory stick, secure digital (SD) memory card, on-processor cache, and the like.

[0128] The ED 110 may further include one or more input / output devices (not shown) or interfaces (such as a wired interface to the internet 150 in FIG. 1). The input / output devices permit interaction with a user or other devices in the network. Each input / output device includes any suitable structure for providing information to or receiving information from a user, such as a speaker, microphone, keypad, keyboard, display, or touch screen, including network interface communications .

[0129] The ED 110 further includes a processor 210 for performing operations including those related to preparing a transmission for uplink transmission to the NT-TRP 172 and / or T-TRP 170,those related to processing downlink transmissions received from the NT-TRP 172 and / or T-TRP 170, and those related to processing sidelink transmission to and from another ED 110. Processing operations related to preparing a transmission for uplink transmission may include operations such as encoding, modulating, transmit beamforming, and generating symbols for transmission. Processing operations related to processing downlink transmissions may include operations such as receive beamforming, demodulating and decoding received symbols. Depending upon the embodiment, a downlink transmission may be received by the receiver 203, possibly using receive beamforming, and the processor 210 may extract signaling from the downlink transmission (e.g. by detecting and / or decoding the signaling). An example of signaling may be a reference signal transmitted by NT-TRP 172 and / or T-TRP 170. In some embodiments, the processor 276 implements the transmit beamforming and / or receive beamforming based on the indication of beam direction, e.g. beam angle information (BAI), received from T-TRP 170. In some embodiments, the processor 210 may perform operations relating to network access (e.g. initial access) and / or downlink synchronization, such as operations relating to detecting a synchronization sequence, decoding and obtaining the system information, etc. In some embodiments, the processor 210 may perform channel estimation, e.g. using a reference signal received from the NT-TRP 172 and / or T-TRP 170.

[0130] Although not illustrated, the processor 210 may form part of the transmitter 201 and / or receiver 203. Although not illustrated, the memory 208 may form part of the processor 210.

[0131] The processor 210, and the processing components of the transmitter 201 and receiver 203 may each be implemented by the same or different one or more processors that are configured to execute instructions stored in a memory (e.g. in memory 208). Alternatively, some or all of the processor 210, and the processing components of the transmitter 201 and receiver 203 may be implemented using dedicated circuitry, such as a programmed field-programmable gate array (FPGA), a graphical processing unit (GPU), or an application-specific integrated circuit (ASIC).

[0132] The T-TRP 170 may be known by other names in some implementations, such as a base station, a base transceiver station (BTS), a radio base station, a network node, a network device, a device on the network side, a transmit / receive node, a Node B, an evolved NodeB (eNodeB or eNB), a Home eNodeB, a next Generation NodeB (gNB), a transmission point (TP) ), a site controller, an access point (AP), or a wireless router, a relay station, a remote radio head, aterrestrial node, a terrestrial network device, or a terrestrial base station, base band unit (BBU), remote radio unit (RRU), active antenna unit (AAU), remote radio head (RRH), central unit (CU), distribute unit (DU), positioning node, among other possibilities. The T-TRP 170 may be macro BSs, pico BSs, relay node, donor node, or the like, or combinations thereof. The T-TRP 170 may refer to the forging devices or apparatus (e.g. communication module, modem, or chip) in the forgoing devices.

[0133] In some embodiments, the parts of the T-TRP 170 may be distributed. For example, some of the modules of the T-TRP 170 may be located remote from the equipment housing the antennas of the T-TRP 170, and may be coupled to the equipment housing the antennas over a communication link (not shown) sometimes known as front haul, such as common public radio interface (CPRI). Therefore, in some embodiments, the term T-TRP 170 may also refer to modules on the network side that perform processing operations, such as determining the location of the ED 110, resource allocation (scheduling), message generation, and encoding / decoding, and that are not necessarily part of the equipment housing the antennas of the T-TRP 170. The modules may also be coupled to other T-TRPs. In some embodiments, the T-TRP 170 may actually be a plurality of T-TRPs that are operating together to serve the ED 110, e.g. through coordinated multipoint transmissions.

[0134] The T-TRP 170 includes at least one transmitter 252 and at least one receiver 254 coupled to one or more antennas 256. Only one antenna 256 is illustrated. One, some, or all of the antennas may alternatively be panels. The transmitter 252 and the receiver 254 may be integrated as a transceiver. The T-TRP 170 further includes a processor 260 for performing operations including those related to: preparing a transmission for downlink transmission to the ED 110, processing an uplink transmission received from the ED 110, preparing a transmission for backhaul transmission to NT-TRP 172, and processing a transmission received over backhaul from the NT-TRP 172. Processing operations related to preparing a transmission for downlink or backhaul transmission may include operations such as encoding, modulating, precoding (e.g. MIMO precoding), transmit beamforming, and generating symbols for transmission. Processing operations related to processing received transmissions in the uplink or over backhaul may include operations such as receive beamforming, and demodulating and decoding received symbols. The processor 260 may also perform operations relating to network access (e.g. initial access) and / or downlinksynchronization, such as generating the content of synchronization signal blocks (SSBs), generating the system information, etc. In some embodiments, the processor 260 also generates the indication of beam direction, e.g. BAI, which may be scheduled for transmission by scheduler 253. The processor 260 performs other network-side processing operations described herein, such as determining the location of the ED 110, determining where to deploy NT-TRP 172, etc. In some embodiments, the processor 260 may generate signaling, e.g. to configure one or more parameters of the ED 110 and / or one or more parameters of the NT-TRP 172. Any signaling generated by the processor 260 is sent by the transmitter 252. Note that “signaling”, as used herein, may alternatively be called control signaling. Dynamic signaling may be transmitted in a control channel, e.g. a physical downlink control channel (PDCCH), and static or semi-static higher layer signaling may be included in a packet transmitted in a data channel, e.g. in a physical downlink shared channel (PDSCH).

[0135] A scheduler 253 may be coupled to the processor 260. The scheduler 253 may be included within or operated separately from the T-TRP 170, which may schedule uplink, downlink, and / or backhaul transmissions, including issuing scheduling grants and / or configuring scheduling-free (“configured grant”) resources. The T-TRP 170 further includes a memory 258 for storing information and data. The memory 258 stores instructions and data used, generated, or collected by the T-TRP 170. For example, the memory 258 could store software instructions or modules configured to implement some or all of the functionality and / or embodiments described herein and that are executed by the processor 260.

[0136] Although not illustrated, the processor 260 may form part of the transmitter 252 and / or receiver 254. Also, although not illustrated, the processor 260 may implement the scheduler 253. Although not illustrated, the memory 258 may form part of the processor 260.

[0137] The processor 260, the scheduler 253, and the processing components of the transmitter 252 and receiver 254 may each be implemented by the same or different one or more processors that are configured to execute instructions stored in a memory, e.g. in memory 258. Alternatively, some or all of the processor 260, the scheduler 253, and the processing components of the transmitter 252 and receiver 254 may be implemented using dedicated circuitry, such as a FPGA, a GPU, or an ASIC.

[0138] Although the NT-TRP 172 is illustrated as a drone only as an example, the NT-TRP 172may be implemented in any suitable non-terrestrial form, it should be noted that the NT-TRP 172 may be removed in some cases. Also, the NT-TRP 172 may be known by other names in some implementations, such as a non-terrestrial node, a non-terrestrial network device, or a nonterrestrial base station. The NT-TRP 172 includes a transmitter 272 and a receiver 274 coupled to one or more antennas 280. Only one antenna 280 is illustrated. One, some, or all of the antennas may alternatively be panels. The transmitter 272 and the receiver 274 may be integrated as a transceiver. The NT-TRP 172 further includes a processor 276 for performing operations including those related to: preparing a transmission for downlink transmission to the ED 110, processing an uplink transmission received from the ED 110, preparing a transmission for backhaul transmission to T-TRP 170, and processing a transmission received over backhaul from the T-TRP 170. Processing operations related to preparing a transmission for downlink or backhaul transmission may include operations such as encoding, modulating, precoding (e.g. MIMO precoding), transmit beamforming, and generating symbols for transmission. Processing operations related to processing received transmissions in the uplink or over backhaul may include operations such as receive beamforming, and demodulating and decoding received symbols. In some embodiments, the processor 276 implements the transmit beamforming and / or receive beamforming based on beam direction information (e.g. BAI) received from T-TRP 170. In some embodiments, the processor 276 may generate signaling, e.g. to configure one or more parameters of the ED 110. In some embodiments, the NT-TRP 172 implements physical layer processing, but does not implement higher layer functions such as functions at the medium access control (MAC) or radio link control (RLC) layer. As this is only an example, more generally, the NT-TRP 172 may implement higher layer functions in addition to physical layer processing.

[0139] The NT-TRP 172 further includes a memory 278 for storing information and data. Although not illustrated, the processor 276 may form part of the transmitter 272 and / or receiver 274. Although not illustrated, the memory 278 may form part of the processor 276.

[0140] The processor 276 and the processing components of the transmitter 272 and receiver 274 may each be implemented by the same or different one or more processors that are configured to execute instructions stored in a memory, e.g. in memory 278. Alternatively, some or all of the processor 276 and the processing components of the transmitter 272 and receiver 274 may be implemented using dedicated circuitry, such as a programmed FPGA, a GPU, or an ASIC. In someembodiments, the NT-TRP 172 may actually be a plurality of NT-TRPs that are operating together to serve the ED 110, e.g. through coordinated multipoint transmissions.

[0141] The T-TRP 170, the NT-TRP 172, and / or the ED 110 may include other components, but these have been omitted for the sake of clarity.

[0142] Basic module structure

[0143] One or more steps of the embodiment methods provided herein may be performed by corresponding units or modules, according to FIG. 4. FIG. 4 illustrates units or modules in a device, such as in ED 110, in T-TRP 170, or in NT-TRP 172. For example, a signal may be transmitted by a transmitting unit or a transmitting module. For example, a signal may be transmitted by a transmitting unit or a transmitting module. A signal may be received by a receiving unit or a receiving module. A signal may be processed by a processing unit or a processing module. Other steps may be performed by an artificial intelligence (Al) or machine learning (ML) module, which can be chosen or removed according to actual requirements. The respective units or modules may be implemented using hardware, one or more components or devices that execute software, or a combination thereof. For instance, one or more of the units or modules may be an integrated circuit, such as a programmed FPGA, a GPU, or an ASIC. It will be appreciated that where the modules are implemented using software for execution by a processor for example, they may be retrieved by a processor, in whole or part as needed, individually or together for processing, in single or multiple instances, and that the modules themselves may include instructions for further deployment and instantiation. It should be noted that, the modules shown in FIG. 4 are only illustrative and should not be construed as limitations to the embodiments of the present disclosure, more or less modules may be included in the device, which is not limited here. For example, the transmitting module and the receiving module may be replaced with one transceiving module. For another example, the ML module can be included or excluded from the device, depending on actual needs.

[0144] Additional details regarding the EDs 110, T-TRP 170, and NT-TRP 172 are known to those of skill in the art. As such, these details are omitted here.

[0145] Example concepts of some terms

[0146] Delay spread: the difference between the time of arrivals of the earliest and the latest beams.Downlink: the channel from BS to UE.Uplink: the channel from UE to BSScheduler: a software and hardware part of BS which distributes frequency and time resources between users and antennas / ports.Resource Element (RE): one subcarrier-one time domain symbol resource atom, in terms of resource allocation, the smallest possible piece of resource.Resource Block (RB): a group of 12 continuous Resource Elements along subcarrier (frequency) domain.Resource Block Group (RBG): a group of several RBsCapacity: the maximum amount of data system is able to transmit per second.Pilot: a reference signal in frequency domain.Symbol: the smallest resource in time domain.

[0147] The above describes possible scenarios or generalized description of the examples of the present disclosure, the motivation and technical concepts of the present disclosure are illustrated in the following.

[0148] Multi-frequency transmission schemes are extremely popular in modem wireless communications. One of the classical multi-frequency schemes is Orthogonal Frequency Division Multiplexing (OFDM), used in Wi-Fi, 4G LTE and 5G NR, etc. OFDM allows to transmit data on several frequencies at the same time. These frequencies are called subcarriers. During propagation through the environment, the signal on each subcarrier experiences distortions. The impact of the environment is described by the propagation channel. To compensate these distortions, a channel needs to be estimated.

[0149] To estimate this channel, some subcarriers are used not for data transmission, but for special signals called pilots or reference signals. Both the transmitter and the receiver have the information about the reference signals (RSs) and their location in frequency domain. The receiver can estimate the channel in RS subcarriers and then recover the channel for all the subcarriers.

[0150] The amount of resources in time and frequency required for channel estimation is called channel estimation overhead (or simply overhead). The overhead is measured in resource elements (REs). There is a tradeoff between accuracy and overhead of channel estimation. Too high overhead will yield good estimation, but few REs will be left for data transmission, thus thecapacity will be low. Too small overhead will leave a lot of REs for data transmission, but the channel estimation will be poor, thus again leading to low capacity.

[0151] In existing solutions, the reference signals in frequency domain are allocated in a comblike structure with the constant distance between subcarriers. The overhead can be lowered by increasing the distance between pilot subcarriers, but this distance is limited by the properties of the channel being estimated. Namely, in scenario with multipath propagation there is the beam that arrives to the receiver first and the beam that arrives to the receiver the last. The difference between the arrival time of these two beams is called delay spread. The maximum distance between pilot subcarriers is limited by the typical value of delay spread in the scenario.

[0152] The reference signals from different antennas can be allocated on the same subcarriers. In such case, a sequence (e.g. Zadoff-Chu sequence) with cyclic shift is used to multiplex the antennas. The maximum number of antennas that can be multiplexed is also limited by the delay spread.

[0153] The following will further elaborate the limit of the delay spread in the existing solution for channel estimation, where sounding reference signals are taken as an example of reference signals for the channel estimation. But it should be noted that other types of signals can also be used as reference signals for the channel estimation, which is not limited in the embodiments of the present disclosure.

[0154] An existing technical solution for channel estimation is based on wideband sounding reference signals (SRSs) sent from UE to BS. SRSs are mapped on a comb-like positioned reference signals. SRS corresponding to the same TX antenna can be mapped on the same subcarriers and separated by cyclic shift. Thus, there are two parameters: comb and cyclic shift (csh).

[0155] Parameter comb specifies how far from each other the reference signal subcarriers are located in the frequency domain, as FIG. 5 shows. The distance between the subcarriers in an OFDM system is defined by SOS (subcarrier spacing), specified in Hz. In time domain, suchsystem can distinguish delays from 0 to seconds. When comb is used, the distance betweenmeasured subcarriers becomes comb • SCS and the range of delays that can be uniquely identified becomes smaller and equal to - — — The CIR (Channel Impulse Response) of achannel estimated with comb is repeated comb times in delay domain. As long as the delay spreadof CIR is smaller than - , such sampling still leads to good channel estimation. Thus, comb comb-SCS parameter can be used to reduce overhead of one TX antenna channel estimation.

[0156] Another parameter, cyclic shift (csh) allows to estimate channels of several antennas on the same subcarriers. Suppose that all available subcarriers are used for channel estimation and we want to estimate channels corresponding to csh antennas on the same subcarriers within one symbol. We take some base sequence (for example, Zadoff-Chu sequence, denoted with small rectangles in FIG. 6). For antenna / port 1, we transmit this sequence as it is. For antenna / port 2, we transmit this sequence with its n-th element multiplied by complex exponent with linear phase increment, as FIG. 6 shows. For every next antenna the linear phase increment becomes larger. At the receiver, we have a sum of all the transmitted sequences. We multiply it element-wise by the original unshifted sequence and take IDFT (Inverse Discrete Fourier Transform), as FIG. 6 shows. When csh antennas are estimated in such way, the delay spread that can be estimated cannot be larger than°

[0157] Comb and csh can be used at the same time to estimate more antennas within one time instance (within one symbol). In this case, the sequence is mapped to comb subcarriers. The maximum delay spread that can be estimated when parameters comb and csh are used is iSCS csh comb'

[0158] The CIR of a particular antenna / port is extracted from the multiplexed CIRs in FIG. 6 using a window, as it is shown in FIG. 7. After the required CIR is separated from the others, its cyclic shift is compensated based on the known port-cyclic shift scheme. The final channel estimation is obtained using some interpolation algorithm, the simplest being DFT (Discrete Fourier Transform) with zero-padding.

[0159] As described above, the maximum values of comb and csh parameters are limited by thedelay spread of the channels to be estimated. If the delay spread is larger than — — - -, there c * c. n * c ci / i is aliasing in delay domain and the estimation quality gets worse. For example, if we consider single antenna CIR estimation with C5' / ?=1 and comb=8 such that the delay spread is larger than - - - , there will be self- interference due to aliasing, as it is shown in FIG. 8. The same will SCS-combapply for the case when cyclic shift is used on a regular comb-like structure, as FIG. 9 shows. In such case there will be interference between CIRs of different antennas which may belong to the same UE or to different UEs, as it is shown in FIG. 9. After the desired antenna / port CIR is filtered by the window, the effects of aliasing are still present in the CIR inside the window. This effect leads to increased error in the further channel estimation, as FIG. 10 shows. It should be noted that the specific values for the above parameters, e.g., comb and csh are just for illustration purpose and should not be construed as limitations to the embodiments of the present disclosure.

[0160] Thus, overhead reduction in the existing channel estimation is limited by the maximum delay spread of the estimated channels. Further, overhead reduction beyond this limit results in corrupted channel estimation due to aliasing.

[0161] In view of the above, the present disclosure provides a reference signal allocation scheme to reduce channel estimation overhead, so as to consume less reference signals for estimating a given channel at the same / similar accuracy of channel estimation compared with the existing solution.

[0162] Generally, it is demonstrated that the overhead can be decreased if compressed sensing (CS) algorithms are used on the premise that the positions of the reference signals are random. However, for ensuring the applicability of the CS algorithm, the main task is how to obtain deterministic rules for reference signal positions which show performance close to random reference signal positions.

[0163] Facing with such objective, the inventor observes that in existing art, the interleaver can be used for permutation purpose, and this permutation would be of particular advantage if we transfer them from existing scenarios into the channel estimation scenario. So in the present disclosure, we make use of interleavers for implementing the random positioning of the reference signals (random sampling or quasi-random sampling). In this way, it makes it possible to take advantage of interleavers for completing the task of RS random positioning in the present disclosure, and consequently ensures the applicability of the CS algorithms, thereby achieving the channel estimation with less RSs. Besides, comparing with the existing solution, with the same number of RSs, the technical solution of the present disclosure may render better channel estimation performance.

[0164] Besides, some existing interleavers are not designed for channel estimation purpose, sothey cannot be directly used, and the specific reason will be introduced in the following.

[0165] Regarding the existing interleaver design, an interleaver is defined in Forward Error Correction (FEC) Part of an existing structure as Turbo code internal interleaver. The main task of the bit interleaver for Turbo code is to spread bits as far as possible from each other. This operation improves the performance of FEC algorithms. The bit interleaver used is a Quadratic Permutation Polynomial (QPP) interleaver. For a sequence of N bits, it is defined by the following simple formula:

[0166] The coefficientsand f2are carefully chosen to guarantee maximum bit spread. For every number of input bits N , the coefficientsand f2are optimized to maximize the spreading factor S :where |i — j\ is the distance between i-th and j-th bits before the spread,is the distance between i-th and j-th bits after the spread.

[0167] However, the QPP bit interleaver was designed for FEC, and the main goal for QPP coefficients optimization was to provide maximum bit spread (adjacent bits should be separated as much as possible after interleaving). Given a block of bits with length K, the indices of bits are interleaved according to the following rule:7r(i) = (fit + f2i2ym°d > whereand f2are coefficients specified in a table for every value K,is the new bit position.

[0168] Return to the idea of the present disclosure, it is to use an interleaver to obtain a quasirandom sampling pattern, which is different from the regular comb-like sampling pattern as in the existing channel estimation. The basic idea of the present disclosure comes from the observation that generating a sampling pattern using the general-purpose uniform random function, for example, from MatLab, yields and IDFT with one sharp peak and almost constant “sidelobes”, as it is shown in FIG. 11. It means that there will be no aliasing effect with such sampling, but there may be small acceptable self-interference of the signal defined by the sidelobes. However, with general-purpose uniform random generators, it is difficult to generate several quasi-randompatterns with zero intersection (zero common subcarriers) in an efficient way. One of the possible options is to use permutation interleavers. Permutations guarantee that if there were no intersection before the permutation, there will be no intersections after the permutation.

[0169] If the quasi-random sampling pattern is generated by interleaving a continuous block of pilots with QPP and coefficients based on the above existing structure, the sidelobe level after the IDFT is too high. FIG. 12 illustrates an example of using the same number of pilots (the same number of 1 in sampling mask), but getting much higher sidelobes if the QPP interleaver (or referred to as QPP) with coefficients from the FEC part are used, in this specific example, the sequence is with a length K=2304, and the coefficients of QPP are: f = 253, f2= 216. High sidelobe level will cause high interference and will distort impulse response of the channel after sampling. Thus, the coefficients of the QPP needs to be carefully chosen to yield permutation that gives low sidelobes level of the IDFT. Since the coefficients from the existing structure cannot be used in the present disclosure, a rule for quasi-random sampling needs to designed taking into account the properties required by the compressed sensing algorithms, and will be described in details later.

[0170] The above briefly describes technical concepts of the present disclosure, and then specific embodiments of the present disclosure will be elaborated in the following description.

[0171] An embodiment of the present disclosure provides a wireless communication method, as shown in FIG. 13, the method includes: step 1302, receiving first information, where the first information is used for determining first frequency resource units for carrying at least one first sequence in a first frequency resource, and a reference signal corresponding to the at least one first sequence is used for measuring a channel over the first frequency resource; where the first frequency resource units in the first frequency resource are determined based on interleaving of second frequency resource units, and the second frequency resource units belong to the first frequency resource.

[0172] The method can be implemented by a first network element, and the first network element may be a terminal device (e.g., UE or any possible implementations of the ED 110 with reference to FIGS. 2 and 3), or may also be a part of the terminal device (e.g., implemented as a module which can be integrated into a device), which is not limited here. It should be noted that in a casewhere the first network element is implemented as a module, the receiving operation may also be an inputting operation, it is not necessary to receive but just to input the first information from a certain device with a receiving function, the specific details with regard to the receiving operation performed by the first network element throughout the document also apply for the inputting operation.

[0173] The first information can be received by a first network element from a second network element. The second network element may be a network device (e.g., BS or any possible implementations of the T-TRP 170 with reference to FIGS. 2 and 3), or may also be a part of the network device (e.g., implemented as a module which can be integrated into a device), which is not limited here. It should be noted that in a case where the second network element is implemented as a module, the transmitting operation may also be an outputting operation, it is not necessary to transmit but just to output the first information to a certain device with a transmitting function, the specific details with regard to the transmitting operation performed by the second network element throughout the document also apply for the outputting operation.

[0174] It should be noted that, in scenarios where UE and BS communicate with each other, the first network element may be UE, and the second network element may be BS.

[0175] The first information may be information from the second network element, e.g., configuration information, or indication information, etc. In a possible implementation, the first information may be carried in at least one of MAC control element (MAC CE), downlink control information (DCI) or radio resource control (RRC), which is not limited here.

[0176] A first sequence is carried on the first frequency resource units, and the number of the first sequence is not limited here. For example, when there is one first sequence, it means that there are no antennas multiplexed on the same subcarriers (in this case csh= , and when there are more than one first sequence, it means that there are antennas multiplexed on the same subcarriers (in this case cshy 1 ). In the case for multiple first sequences, different first sequences are multiplexed on the same first frequency resource units, that is, their positions are the same, but with different cyclic shifts (e.g., as cyclic shifts shown in FIG. 6).

[0177] The first frequency resource units are frequency resource units after interleaving, they may correspond to a first sampling pattern for a channel over the first frequency resource, and the first frequency resource units are obtained from second frequency resource units, these secondfrequency resource units are frequency resource units before interleaving which may correspond to a second sampling pattern for the channel over the first frequency resource, and the second sampling pattern is distinct from the first sampling pattern. For example, the first frequency resource may include frequency resource units, and a sampling pattern of the frequency resource units in the first frequency resource may refer to a pattern with positions of reference signals for channel estimation being 1 and other positions being 0, since the transmission of the reference signals on the first frequency resource units would be like sampling of the channel over the first frequency resource.

[0178] The first frequency resource units and the second frequency resource units are both within or both belong to the first frequency resource, they will not be existing simultaneously, the second frequency resource units are mentioned simply for the purpose of describing the interleaving, the obtained first frequency resource units will be later used for transmitting or receiving reference signals.

[0179] The interleaving from the second frequency resource units to the first frequency resource units ensures that the first sampling pattern is a quasi-random sampling pattern, so that reference signals used for channel estimation can be put according to this quasi-random sampling pattern, randomization of positions of the reference signals are implemented, thus CS algorithms can be used for recovering CIR of the channel over the first frequency resource, thereby reducing the channel estimation overhead.

[0180] Regarding the number of resource elements included in a single frequency resource unit, in a possible implementation, at least one of first frequency resource units includes multiple resource elements, or, each of the first frequency resource units includes one resource element. It means that the interleaving can be performed at a block level (block-wise), where a block includes multiple resource elements; and can also be performed at a resource element level (element- wise).

[0181] Regarding the interleaving design in the present disclosure, in a possible implementation, at least one parameter of the interleaving is associated with a total number of resource elements (REs) included in the first frequency resource. When the total number of REs varies, the parameter(s) associated with the interleaving may vary accordingly. When choosing the parameter(s) associated with the interleaving, the total number of the resource elements included in the first frequency resource needs to be taken into account. For example, the interleaving canbe implemented according to a correspondence between the total number of REs included in the first frequency resource and interleaving parameters, (e.g., a table stored with the correspondence, specific implementations for the interleaving are not limited here), then an index in the table can be used for locating the parameter(s) associated with the interleaving.

[0182] For example, when the interleaving is implemented by an interleaver, a parameter of the interleaver is associated with the total number of REs included in the first frequency resource, and specific manners for designing the parameter of the interleaver will be described later. For another example, when the interleaving is implemented by means of a predefined table stored with the foregoing mentioned correspondence, a parameter of the interleaving can be obtained by looking up the predefined table with the total number of REs included in the first frequency resource. Table 1 in the following may be an example for such predefined table.

[0183] The above focuses on a basic designing principle for the interleaving parameter, and next the interleaving type will be described.

[0184] In a possible implementation, positions of the second frequency resource units are associated with a type of the interleaving. The type of the interleaving (or referred to as interleaving type) may define a general rule for mapping the second frequency resource units to the first frequency resource units. When the interleaving is implemented by an interleaver, the type of the interleaving refers to a specific type of the interleaver, e.g., a quadratic permutation polynomial (QPP) interleaver, an interleaver based on a pseudo-noise (PN) sequence, etc. Different types of interleaving may give different patterns based on which reference signals for channel estimation can be put. The positions of the second frequency resource units may vary based on the type of the interleaving, i.e., a pattern of frequency resource units before interleaving can be different if different types of the interleaving are adopted. For example, when the interleaving type corresponds to a QPP interleaver, a pattern of the second frequency resource units would be in large blocks of resource elements. For another example, when the interleaving type corresponds to an interleaver based on a PN sequence, a pattern of the second frequency resource units can be in regular distribution. Besides, different interleavers with different parameters but of the same interleaving type will be applicable to the same pattern of frequency resource units before interleaving, but they are still different interleavers. For example, when for QPP interleaver, different parameters will represent different interleavers, but they are applicable to the same patternof the second frequency resource units.

[0185] In a possible implementation, the interleaving includes appliance of at least one of a cubic permutation polynomial (CPP) interleaver, a quadratic permutation polynomial (QPP) interleaver, a Takeshita-Costello interleaver, a Welch-Costas interleaver, an interleaver based on a pseudonoise (PN) sequence or an interleaver based on a random integer sequence. The interleaving can be performed by means of a CPP interleaver, a QPP interleaver, a Takeshita-Costello interleaver, a Welch-Costas interleaver, an interleaver based on a PN sequence or an interleaver based on a random integer sequence, or a combination of two or more of the foregoing mentioned interleavers. It provides flexibility for the foregoing mentioned interleaving, thus the interleaving strategy can be designed according to actual needs. It should be noted that, the listed interleavers are only illustrative and not restrictive.

[0186] Next, specific manners for designing the parameter of the interleaver will be introduced, with the interleaving being implemented by a QPP interleaver as an example.

[0187] In a possible implementation, the interleaving includes appliance of the QPP interleaver; where the interleaving is based on a first coefficient and a second coefficient, the first coefficient and the coefficient are used for determining a sampling pattern of all frequency resource units in the first frequency resource. In another possible implementation, the first coefficient and the second coefficient are used for obtaining a one-to-one correspondence between positions of the second frequency resource units and positions of the first frequency resource units. The first coefficient is represented as a coefficient f2inthe foregoing mentioned formula of the QPP interleaver. The second coefficient is represented as a coefficientin the foregoing mentioned formula of the QPP interleaver. By setting appropriate first and second coefficients, the positions of the second frequency resource units and the positions of the first frequency resource units are in one-to-one correspondence, random positioning of the positions of the first frequency resource units can be guaranteed. In addition, the first coefficient and the second coefficient can be chosen in such a way that the signal recovery properties with CS algorithms will be improved.

[0188] In a possible implementation, a first factorization of the first coefficient is represented as a product of multiple first integers and an interleaving factor, where the interleaving factor is an integer not divisible by any one of the multiple first integers, and each of the multiple first integers is a prime number. In a possible implementation, a second factorization of a total number ofresource elements in the first frequency resource is represented as a product of the multiple first integers with multiple first powers corresponding to the multiple first integers respectively, and at least one of the first powers is greater than one; where the second coefficient is not divisible by any one of the multiple first integers, that is, each of the multiple first integers has its corresponding first power in the expression of the second factorization. As mentioned before, here, the first coefficient is represented as a coefficient f2and the second coefficient is represented as a coefficient f . It should be noted that in the following, the multiple first integers may be respectively represented as p • p2• ... • PT, the interleaving factor may be represented as q, the total number of resource elements in the first frequency resource may be represented as L, and the multiple first powers may be respectively represented as nP1, nP2, ... nPT.

[0189] The coefficientsand f2are chosen so that QPP is a permutation and so that the maximum level of sidelobes of the sampling pattern generated using QPP is the lowest possible. More specifically, given the factorization of the total number of REs in the first frequency resource as L = p”P1p2Pz... pPPTsuch that plfp2—PT are prime numbers and nP1, nP2, ... nPTare natural numbers, the coefficients of the QPP interleaver are chosen such that: L is not divisible by any of the numbers among pltp2... pTandwhere q is any integer number not divisible by any of the numbers among p1, p2... pT.

[0190] Regarding how a first network element obtains the parameters of the QPP interleaver, in a possible implementation, the first coefficient and the second coefficient are predefined, or, the first information indicates the first coefficient and the second coefficient. It means that the first coefficient and the second coefficient can be predefined for the first network element (e.g., at both sides, the second network element and the first network element), or can be obtained by the first network element from a second network element, for example, the second network element directly transmits or indirectly indicates the first coefficient and the second coefficient to the first network element, thereby improving flexibility of obtaining the coefficients.

[0191] In a possible implementation, there may be a correspondence between the first coefficient and the second coefficient, for example, such correspondence can be implemented as a table, and the first coefficient and the second coefficient can be determined based on a table. In a case that afirst network element stores a table, and the table represents a correspondence between an index and the coefficients, for example, the following table 1. In table 1 , A refers to any natural number such that it is not divisible by any of prime factors of NRE(e.g., the foregoing mentioned Pi, p2... PT), and any of the listed values formay be suitable for a given number of REs, where a specific value ofcan be fixed or further indicated according to actual needs. It should be noted that, table 1 is only illustrative but not restrictive, more or less entries can be included in such table. The first network element can easily obtain target first and second coefficients via a target index indicated by a second network element, and in this way, signaling can be saved.Table 1 Example coefficients for QPP interleaver

[0192] With the introduction of the QPP interleaver, the frequency hopping scheme in the present disclosure may be different from the existing frequency hopping scheme. In a possible implementation, at least one first frequency resource unit of the first frequency resource units includes multiple resource elements; a position of a third frequency resource unit on a second frequency resource is determined based on the QPP interleaver and a position of the at least one first frequency resource unit, where the second frequency resource and the first frequency resource may be on different symbols, and the third frequency resource unit is used for carrying at least one second sequence. The second frequency resource refers to another first frequency resource (or afurther first frequency resource), and the another first frequency resource and the foregoing one first frequency resource may be on different symbols, that is to say, they can be on adjacent symbols, and can also be on non-continuous symbols. Therefore, the frequency hopping is applied between the at least one second frequency resource unit and the third frequency resource unit, a hopping position of the third frequency resource unit after frequency hopping is dependent on a position of the above at least one first frequency resource unit, so the at least one first frequency resource unit is taken as a frequency resource unit before interleaving, and the third frequency resource unit is taken as a frequency resource unit after interleaving, in this way, the position of the third frequency resource unit can thus be obtained by inputting the position of the at least one first frequency resource unit into the QPP interleaver. It should be noted that the at least one first frequency resource unit may include multiple first frequency resource units, that is, there are multiple first frequency resource units, each includes multiple resource elements (the number of resource elements for each said first frequency resource unit may vary), then after frequency hopping, each said first frequency resource unit will have its corresponding third frequency resource unit.

[0193] In a case that a second frequency resource unit includes multiple resource elements, it means that the interleaving can be performed at a block level, and frequency hopping can be performed in such case. The position of the frequency resource unit after frequency hopping is associated with the starting position of the frequency resource unit and the QPP interleaver. Instead of covering all available frequency resource units in the normal frequency hopping, some frequency resource units can be skipped in the above described frequency hopping by virtue of the QPP interleaver design, thereby reducing the channel estimation overhead.

[0194] As mentioned before, in addition to the QPP interleaver, other interleavers can also be used in the present disclosure, and some interleavers will be further described in the following.

[0195] CPP interleaver or a general interleaver based on permutation polynomial

[0196] For a sequence of N bits, the CPP interleaver is defined by the following formula:

[0197] The coefficients are supposed to be integers. There is also a rule for coefficients f , f2and3, such that the CPP interleaver yields a permutation (one-to-one correspondence of elements before and after interleaving). There is also a rule for the coefficients to yield a low sidelobe level.

[0198] For a sequence of N bits, a general permutation-based interleaver with permutation polynomial of degree D is defined by:

[0199] The same can be said about the general interleaver based on permutation polynomial. The coefficients are supposed to be integers. There is also a rule for coefficientsf2, ... / D, such that the interleaver yields a permutation (one-to-one correspondence of elements before and after interleaving). Specific rules for the coefficients may also be designed to yield a low sidelobe level.

[0200] It should be noted that, generally the polynomial may also contain coefficient f0, that is:

[0201] However, the value of f0has no impact on the interleaver performance. Therefore, it is usually assumed to be 0.

[0202] An interleaver based on a PN-sequence

[0203] Since PN-sequences have good sidelobe levels, they can also be applied in the channel estimation scenario. However, these sequences cannot be directly applied to pilot subcarriers interleaving because for a given length N, there are a fixed number of 0s and Is. In the present disclosure, the Is represent the presence of pilot signal and we want to be able to have an interleaver for various number of Is within the same length N.

[0204] Though PN-sequences cannot be directly applied for the needs of the present disclosure, there is a way to use them to generate an interleaving pattern with desired properties (low sidelobes). In a possible implementation, the interleaving includes appliance of the interleaver based on the PN sequence, and the total number of resource elements in the first frequency resource is equal to a power of two. That is, PN-sequences can be generated for lengths N = 2q— 1 for a natural number q and one 0 is appended in the process of the generation of the permutation. PN- sequences can be generated using a linear feedback shift register with the feedback connections defined by a primitive polynomial of degree q.

[0205] Given such sequence of zeros and ones, we can define an inverted sequence. The interleaver design can be described by the following procedure. For a given PN-sequence, a zero is appended in the end. Thus, the number of 1 s and 0s in a resulting sequence is the same according to the property of PN-sequence. Next, an inverted PN-sequence is generated by applying an element-wise NOT to the appended PN-sequence, as shown in (a) of FIG. 14. Then, for everyelement of the inverted PN-sequence, the index of this element is associated with the closest same value element in the non-inverted PN-sequence, as shown in (b) and (c) of FIG. 14. For example, the first zero of the inverted PN-sequence (i = 1) is associated with the first zero of the noninverted PN-sequence (n(i = 1) = 3). The index of the next element of the inverted PN-sequence (the second zero, i = 2) is associated with the second zero index of the non-inverted sequence (zr(i = 2) = 4). For the next element, 7i(i = 3) = 1 and so on, as (c) of FIG. 14 illustrates.

[0206] After all the elements of the inverted PN-sequence are processed in such way, a permutation rule is ready. This interleaver yields good results applied to comb-like structures.

[0207] An interleaver based on a random integer sequence

[0208] Similar sampling patterns can also be constructed from common random integer generation algorithms or their modifications. Examples of such random integer generation algorithms are Mersenne Twister (and its modifications), Combined Multiple Recursive Random Numbers generators and Lagged Fibonacci generator, though some other random numbers generators can be used yielding tiny change in performance.

[0209] Given the maximum number of subcarriers N and the seed value S, on every step the generator produces a number from 1 to N. The sequence of such numbers has uniform random positioning and is defined by the seed value S such that different S values produce different random sequences. In this sequence, however, the numbers may repeat, so it may not define a permutation. To obtain a permutation from a random integer generator, we can keep track of all the random numbers that were generated. If at some step the random generator outputs the number that was already generated earlier, we simply discard the output of this step and call the generator again. This can be repeated until all N distinct values are generated.

[0210] This is a simple and straightforward algorithm, and some modifications can be done using the similar idea. From the communication system point of view, simply the seed and the number of subcarriers need be notified to define the permutation on both the second network element and the first network element. Therefore, the overhead of notification of such interleaver is low.

[0211] Takeshita-Costello interleavers

[0212] For length N = 2qthese interleavers are defined using the following formula:where k and v are integers.

[0213] In this case, a Takeshita-Costello interleaver is a kind of QPP interleaver with non-integer k k coefficients and non-zero coefficient f0= v, see the following formula:

[0214] For lengths S that are not power of 2 (S < N = 2q), the Takeshita-Costello interleaver can be implemented using an existing algorithm, which will be not described here.

[0215] It should be noted that, in most cases if two interleavers provide a good sidelobe level, then their composition also provides a good sidelobe level. That is, if we have interleaver- 1 defined as 7Ti(i) and interleaver-2 defined as zr2(i), their composition is defined as 7T17r2=Different interleavers or interleavers of the same type can be combined in such a way. For example, TTiC and zr2(i) can be QPP interleavers with different coefficients, or, for example, 71^(0 can be an interleaver based on a random number generator and TT2(i) can be an interleaver based on a PN-sequence. In addition, a composition of several levels can also be created, for example,

[0216] The first network element can directly receive information about the first frequency resource units for carrying the at least one first sequence in the first frequency resource, in this case, the first frequency resource units may be determined by a second network element. It should be noted that, the first frequency resource units may also be determined by the first network element. In a possible implementation, the first information may indicate the second frequency resource units. The first network element may obtain the second frequency resource units before the interleaving, and perform the interleaving based on a predefined rule to obtain the first frequency resource units. In this case, it is not necessary for the second network element to notify the first network element of the first frequency resource units after the interleaving. As an example of indicating the second frequency resource units, the first information may include a bitmap for indicating the second frequency resource units.

[0217] In the present disclosure, the channel estimation can be performed by a second network element (e.g., BS), i.e., an uplink channel estimation is performed. In this case, the first network element (e.g., UE) receives the first information, and transmits the at least one first sequence overthe first frequency resource. It means that UE transmits reference signals corresponding to the at least one first sequence to BS, and then BS performs the channel estimation based on the reference signals. In a possible implementation, the reference signal corresponding to the at least one first sequence is a sounding reference signal (SRS) or a demodulation reference signal (DMRS).

[0218] The above uplink channel estimation may be used in Time Division Duplex (TDD) MIMO OFDM systems. In a possible implementation, BS configures the second frequency resource units for every antenna of the UE for a group of UEs. BS chooses the number of REs that reference signals will occupy and time location of the reference signals for every second frequency resource unit. BS then sends this configuration to UE through the control channel. UE may use a predefined table to determine coefficients of the QPP interleaver for the given number of subcarriers (REs). Based on the coefficients and the information about the second frequency resource units, UE determines the first frequency resource units. UE then uses the first frequency resource units to send the reference signals (e.g., Sounding Reference Signals) to the BS. Based on the received reference signals, BS performs the channel estimation using compressed sensing algorithms.

[0219] The channel estimation can also be performed by a second network element (e.g., BS), i.e., a downlink channel estimation is performed. In this case, the first network element (e.g., UE) receives the first information, and receives the at least one first sequence over the first frequency resource. It means that BS transmits reference signals corresponding to the at least one first sequence to UE, and then UE performs the channel estimation based on the reference signals. In a possible implementation, the reference signal corresponding to the at least one first sequence is a channel state information reference signal (CSI-RS).

[0220] The above downlink channel estimation may be used in Frequency Division Duplex (FDD) MIMO OFDM systems. In a possible implementation, BS configures the second frequency resource units for every antenna of the UE for a group of UEs. After that BS sends information about the second frequency resource units to every UE through the control channel. BS determines the first frequency resource units based on the second frequency resource units using the QPP interleaver with coefficients from the predefined table. BS uses the first frequency resource units to determine CSI-RS configuration for every UE, and then sends CSI-RS signals to UEs. UE also calculates the first frequency resource units based on the received second frequency resource unitsand the coefficients from the predefined table. Thus, UE determines the configuration of CSI-RS that BS uses. After that, UE receives CSI-RS from BS and performs channel estimation based on these reference signals using compressed sensing algorithms.

[0221] In a possible implementation, still referring to FIG. 13, the method includes: step 1302, receiving first information, where the first information is used for determining first frequency resource units for carrying at least one first sequence in a first frequency resource, and a reference signal corresponding to the at least one first sequence is used for measuring a channel over the first frequency resource; where the first frequency resource units in the first frequency resource are determined based on interleaving of second frequency resource units, and the second frequency resource units belong to the first frequency resource; step 1304, receiving second information, where the second information is used for determining fourth frequency resource units for carrying at least one third sequence in a third frequency resource, and a reference signal corresponding to the at least one third sequence is used for measuring a channel over the third frequency resource; where the first frequency resource units and the fourth frequency resource units are non-overlapping in a frequency domain.

[0222] The first information and the second information are only used for distinguishing frequency resource units allocated to different antennas, it should be noted that, the first information and the second information can be combined into a single piece of information, can also be separated as two pieces of information, which is not limited here as long as corresponding information can be received. A type of the reference signal corresponding to the at least one third sequence is the same as a type of the reference signal corresponding to the at least one third sequence. There can be more than one antenna to transmit or receive reference signals with nonoverlapping frequency resource units, and the process of transmitting or receiving reference signals for each antenna is similar.

[0223] The at least one third sequence may also include one or multiple sequences. For example, when there is one third sequence, it means that there are no antennas multiplexed on the same subcarriers (in this case csh=l , and when there are more than one third sequence, it means that there are antennas multiplexed on the same subcarriers (in this case csh^ ). In the case for multiplethird sequences, different third sequences are multiplexed on the same fourth frequency resource units, that is, their positions are the same, but with different cyclic shifts (e.g., as cyclic shifts shown in FIG. 6).

[0224] With the wireless communication method provided by the present disclosure, the first frequency resource units are determined based on interleaving of the second frequency resource units, the interleaving ensures random-like properties of the first frequency resource units required for CS algorithms, in other words, reference signals carried on the first frequency resource can be in random positioning, it makes compressed sensing algorithms applicable for estimating a channel over the first frequency resource, thus less resource elements are used for the channel estimation, i.e., channel estimation overhead can be reduced, and more resource elements can be left for other uses.

[0225] In the above, the wireless communication method of the present disclosure is described from the perspective of a first network element. In the following, a wireless communication method of the present disclosure will be described from the perspective of a second network element in combination with FIG. 15. FIG. 15 shows a schematic flowchart of another wireless communication method according to one or more embodiments of the present disclosure. The method can be implemented by a second network element. As shown in FIG. 15, the method may include: step 1502, transmitting first information, where the first information is used for determining first frequency resource units for carrying at least one first sequence in a first frequency resource, and a reference signal corresponding to the at least one first sequence is used for measuring a channel over the first frequency resource; where the first frequency resource units in the first frequency resource are determined based on interleaving of second frequency resource units, and the second frequency resource units belong to the first frequency resource.

[0226] The second network element may be a network device, or may also be a part of the network device (e.g., implemented as a module which can be integrated into a device), which is not limited here. It should be noted that in a case where the second network element is implemented as a module, the transmitting operation may also be an outputting operation, it is not necessary to transmit but just to output the first information to a certain device with a transmitting function, thespecific details with regard to the transmitting operation performed by the second network element throughout the document also apply for the outputting operation.

[0227] For the above step, reference may be made to the forgoing relevant description at the first network element, which will not be repeated here.

[0228] In a possible implementation, at least one parameter of the interleaving is associated with a total number of resource elements (REs) included in the first frequency resource.

[0229] In a possible implementation, positions of the second frequency resource units are associated with a type of the interleaving.

[0230] In a possible implementation, the interleaving includes appliance of at least one of a cubic permutation polynomial (CPP) interleaver, a quadratic permutation polynomial (QPP) interleaver, a Takeshita-Costello interleaver, a Welch-Costas interleaver, an interleaver based on a pseudonoise (PN) sequence or an interleaver based on a random integer sequence.

[0231] In a possible implementation, the interleaving includes appliance of the QPP interleaver; where the interleaving is based on a first coefficient and a second coefficient, the first coefficient and the second coefficient are used for determining a sampling pattern of all frequency resource units in the first frequency resource.

[0232] In a possible implementation, the first coefficient and the second coefficient are used for obtaining a one-to-one correspondence between positions of the second frequency resource units and positions of the first frequency resource units.

[0233] In a possible implementation, a first factorization of the first coefficient is represented as a product of multiple first integers and an interleaving factor, where the interleaving factor is an integer not divisible by any one of the multiple first integers, and each of the multiple first integers is a prime number.

[0234] In a possible implementation, a second factorization of a total number of resource elements in the first frequency resource is represented as a product of the multiple first integers with multiple first powers corresponding to the multiple first integers respectively, and at least one of the first powers is greater than one; wherein the second coefficient is not divisible by any one of the multiple first integers.

[0235] In a possible implementation, the first coefficient and the second coefficient are predefined, or, the first information indicates the first coefficient and the second coefficient.

[0236] In a possible implementation, the first coefficient and the second coefficient are determined based on a table.

[0237] In a possible implementation, at least one first frequency resource unit of the first frequency resource units includes multiple resource elements; a position of a third frequency resource unit on a second frequency resource is determined based on the QPP interleaver and a position of the at least one first frequency resource unit, where the second frequency resource and the first frequency resource are on different symbols, and the third frequency resource unit is used for carrying at least one second sequence.

[0238] In a possible implementation, the interleaving includes appliance of the interleaver based on the PN sequence, the total number of resource elements in the first frequency resource is equal to a power of two.

[0239] In a possible implementation, the first information further indicates the second frequency resource units.

[0240] In a possible implementation, the first information includes a bitmap for indicating the second frequency resource units.

[0241] In a possible implementation, at least one of first frequency resource units includes multiple resource elements, or, each of the first frequency resource units includes one resource element.

[0242] In a possible implementation, the method further includes: receiving the at least one first sequence over the first frequency resource.

[0243] In a possible implementation, the reference signal corresponding to the at least one first sequence is a sounding reference signal (SRS) or a demodulation reference signal (DMRS).

[0244] In a possible implementation, the method further includes: transmitting the at least one first sequence over the first frequency resource, where the reference signal corresponding to the at least one first sequence is a channel state information reference signal (CSI-RS).

[0245] In a possible implementation, the first information is carried in at least one of MAC control element (MAC CE), downlink control information (DCI) or radio resource control (RRC).

[0246] In a possible implementation, still referring to FIG. 15, the method includes: step 1502, transmitting first information, where the first information is used for determining first frequency resource units for carrying at least one first sequence in a firstfrequency resource, and a reference signal corresponding to the at least one first sequence is used for measuring a channel over the first frequency resource; where the first frequency resource units in the first frequency resource are determined based on interleaving of second frequency resource units, and the second frequency resource units belong to the first frequency resource; step 1504, transmitting second information, where the second information is used for determining fourth frequency resource units for carrying at least one third sequence in a third frequency resource, and a reference signal corresponding to the at least one third sequence is used for measuring a channel over the third frequency resource; where the first frequency resource units and the fourth frequency resource units are non-overlapping in a frequency domain.

[0247] It should be understood by a person skilled in the art that, the relevant description of the wireless communication method from the perspective of the second network element in the embodiments of the present disclosure may be understood with reference to the relevant description of the wireless communication method from the perspective of the first network element in the embodiments of the present disclosure.

[0248] In order to elaborate the wireless communication methods of the present disclosure more clearly, in the following, taking element-wise and block- wise interleaving as examples, the method will be described in more details.

[0249] In the following, specific examples will be given for elaborating the solution of the present disclosure more clearly.

[0250] First of all, a resource unit (RU) may be defined in frequency domain. It is a set including one or several blocks of continuous REs (subcarriers) as in FIG. 16a, one or several non-continuous REs as in FIG. 16b, or a combination of blocks of continuous REs and non-continuous REs as in FIG. 16c.

[0251] A scheduler at the BS side may configure a frequency resource as in the existing solution, e.g., as shown in FIG. 17. In this example there are 16 RUs, each RU defines a regular comb-like pattern (comb 16) of pilot subcarriers. The RUs differ from each other by an offset value that runs from 0 to 15. There is no intersection in frequency domain between the 16 RUs. Together all 16 RUs cover all available REs. For example, the 16 RUs are assigned to antennas / ports 1-16 insymbol #7, and the same 16 RUs are assigned to antennas / ports 17-32 in symbol #8. A type of the symbol may be an OFDM or SC-FDMA symbol, which is not limited in the present disclosure.

[0252] The scheduler determines the second RU (the tag block for one antenna of one symbol, and the tag block includes multiple continuous REs), e.g., by means of putting all pilot subcarriers in continuous blocks, as shown in FIG. 17. There are as well 16 RUs, but the positions of the pilot signals are different in frequency domain. There is no overlapping in frequency domain between RUs, combined together all RUs cover all the available REs. Here, the resource occupied by one column for one antenna in one symbol may be a specific example of the above mentioned first frequency resource, and the tag block (including multiple continuous REs) of FIG. 17 may be a specific example of the above mentioned second frequency resource units.

[0253] It should be noted that FIG. 17 simply shows one possible implementation of the second RUs, it is also possible that for one RU the tag block is divided into two small second frequency resource units, various distribution would be possible as long as the second frequency resource units are irregularly distributed.

[0254] Next, the QPP interleaver is applied for each second RU to obtain a corresponding first RU, so the tag blocks in each first RU (a column) for one antenna of one symbol is determined, until all first RUs are determined, the foregoing mentioned second frequency resource units may be frequency resource units (continuous REs in the tag block) on one second RU (one column) in FIG. 17, the foregoing mentioned first frequency resource units may be frequency resource units (tag blocks) on one first RU (one column) of FIG. 17. Let’s denote the number of all REs as N, and let’s agree that the pilot location is defined by a binary array, where 1 represents pilot and 0 represents absence of pilot. Such an array can be formed for every antenna / port within the second RU. QPP then applied to every such binary array to get interleaved pilots positions aswhere coefficientsand f2are chosen according to the foregoing mentioned rules, i is the position of REs included in the second RU, and 7r(i) is the position of REs of the first RU. The first RU is then used to determine reference subcarriers which will be used for reference signals transmission, as it is shown in FIG. 17.

[0255] The receiver should obtain the information about first frequency RUs or about second frequency RUs, N and coefficients and f2from the transmitter through the control channel.Thus, the receiver knows which REs correspond to which TX antennas / ports. The channel estimation can be performed using compressed sensing algorithms, including but not limited to Orthogonal Matching Pursuit algorithm.

[0256] There may be N frequency RUs in frequency domain and Li time domain units (e.g., OFDM or SC-FDMA symbols) in time domain for forming the quasi-random sampling pattern proposed by the present disclosure. The first frequency RUs and the second frequency RUs may include K frequency RUs in frequency domain and L2 time domain units in time domain. The specific values of K, Li and L2 are not limited here. In general, K may be larger than or equal to N, and Li can be different from L2.

[0257] The channel estimation can be performed using wideband reference signals as shown in FIG. 17, and can also be performed using frequency hopping. The frequency hopping scheme will be described with reference to FIGS. 18Ato 18C.

[0258] In this example, assume that there are a total of 10 RBGs for RS transmission. In the existing solution shown in (1) of FIG. 18A and (1) of FIG. 18B, the corresponding frequency hopping scheme may be one RBG for one symbol, and there is no interval between two adjacent RBGs, 10 symbols are needed to perform the channel estimation for one port.

[0259] Compared with the existing solution, if the frequency hopping is performed using the idea of the present disclosure, simply 5 symbols are needed to perform the channel estimation for one port, an interval between two adjacent RBGs may be unequal. The frequency hopping can be achieved with the help of QPP interleaver, since QPP interleaver (or any other interleaver) can be applied to interleave not only RE indices (subcarrier-level interleaving) as FIG. 17 shows, but also Resource Block Group indices (RBG, one RB = 12 REs, one RBG=48 REs) as the lower part of FIG. 18A shows (as indicated by (2) of FIG. 18 A). As shown in (2) of FIG. 18A, where positions of 5 RBGs are associated with the QPP interleaver. The rest 5 symbols can be used for channel estimation of other ports. Specifically, in (2) of FIG. 18 A, the first five blocks are chosen to perform the interleaving, with each of the chosen blocks including several REs on which RSs are transmitted. However, as shown on the top part of FIG. 18A (as indicated by (1) of FIG. 18 A), all blocks should be included with RSs (with a comb-like structure in each block) in the existing solution. It can be seen that, for measuring the same bandwidth (with the same number of REs as NRE), less blocks are used compared with the existing solution.

[0260] Similarly, in (2) of FIG. 18C, not the first five blocks, but five blocks as indicated are chosen to perform the interleaving, the specific interleaving may be similar to (2) of FIG. 18 A, which will not be repeated here for brevity.

[0261] It should be noted that, the positions of frequency resource units before interleaving are associated with the type of the interleaver. For example, for QPP, RUs before the interleaving include one or several blocks, inside each block there can be a comb-like structure or a continuous structure. For QPP, the frequency resource units before interleaving would not be of a regular distribution, since such comb-like structure as an input for QPP will lead to a comb-like output and has no benefit for the present disclosure. For another example, for PN-sequence based interleaver (i.e., an interleaver based on a PN- sequence), on the other hand, good results can be achieved if the original RUs are comb-like on RE level. So, the choice of positions of RUs before the interleaving in general depends on the type of interleaver.

[0262] Regarding the channel estimation, for example, as shown in FIG. 19 A, the channel estimates at Nppilot subcarriers, can be used as measured signal (left part of the equation in FIG. 19A), the row-selection matrix P containing only one 1 in a row can be seen as a measurement matrix, DFT or truncated DFT matrix F can be seen as a dictionary and the pure Channel Impluse Response htcan be seen as the sparse signal to be estimated. Note that the sampling pattern defines the measurement matrix P. Specifically, the measurement matrix P is constructed as a submatrix of an identity matrix. Given a sampling pattern vector of Nscelements with 1 signifying presence of pilots and 0 signifying absence of pilots, we may choose the i-th row of the identity matrix if the i-th element of the sampling pattern equals to 1. Any existing compressed sensing algorithm can be applied to solve this equation.

[0263] One of the compressed sensing algorithms that can be used to recover CIR is Orthogonal Matching Pursuit (OMP), and this algorithm can be described as follows.

[0264] Input parameters of this algorithm include: vector of channel measurements h on the pilot subcarriers; row-selection matrix P, each row of P has only one 1 and all other 0; where matrix P is determined by the sampling pattern (positions of the pilots subcarriers); and dictionary F (usually it is a dft-matrix).stopping criteria (e.g. maximum number of iterations or norm of the residual)

[0265] The initialization step of this algorithm: set the residual res = h , set the sensing matrix as A = P • F, initialize the chosen index set A as an empty set 0, initialize iteration counter k = 1; initialize the estimated sparse signal (CIR) as a vector of zeros z E CNRESX1.

[0266] If stopping criteria is not met, the following steps will be executed.

[0267] Step 1. Calculate the dot products of the residual res with all available columns of the sensing matrix A. The indices of the available columns are not from the index set A. Find the index i of the column of A that yields the highest dot product with the residual.

[0268] Step 2. Append i to the index set A.

[0269] Step 3. Update the estimate z of sparse signal (CIR). For all indices from the set A update the elements of z as a solution to the following least-squares problem:Set the coefficients of z at indices that are not in A to zeros: x(i g A) = 0.

[0270] Step 4. Update the current estimate of the left-side signal hfkusing non-zero elements of the current estimate x of the sparse signal and the chosen columns of the sensing matrix A(: , A): hfk= A(: ,A) • x(t E A).

[0271] Step 5. Update the residual with: res = h - hf increase the iteration counter k = k + 1.

[0272] The stopping criteria can be, for example, the maximum number of iterations k or the criteria that the norm of the residual is less then a specified threshold s: ||resfc|| < £, provided as an input parameter.

[0273] The least-squares problem in step 3 can be solved, for example, using Moore-Penrose pseudoinverse:

[0274] The recovery properties of the given measurement matrix P and the dictionary F canbe described using mutual coherence metric. To define mutual coherence, we may first form the sensing matrix as A = P • F. The mutual coherence (A) is defined as the maximum absolute value of normalized dot products between different columns of matrix A:where N is the total number of columns in the sensing matrix A, ) denotes dot product and || ||Fdenotes Frobenius norm.

[0275] Lower mutual coherence means better recovery with any compressed sensing algorithm, the lowest possible value of p may be zero for orthogonal sensing matrix. For compressed sensing task as in FIG. 19A with the dictionary F fixed as DFT matrix or truncated DFT matrix, minimization of mutual coherence is equivalent to sidelobe level minimization. The unnormalized dot product between columns i and j in such case is whereis the number of pilot signals and ptis the position of the Lth pilot inside N subcarriers. At the same time, the expression for the m-th sidelobe is Sm= so the dotproduct between columns i and j is the same as the m-th sidelobe (m=i-j), as shown in FIG. 19B.

[0276] There is a theoretical bound on how low the mutual coherence of a matrix can be. This bound is referred to as Welch bound. For the total number of subcarriers N and given only Nppilots, the following lower bound for the mutual coherence stands:

[0277] As mentioned before, coefficientsand f2are designed for QPP interleaver to ensure the signal recovery properties, e.g., the lowest mutual coherence of the corresponding sensing matrix. For example, in a case where the factorization of the total number of subcarriers includes 2 and 3, the mutual coherence may be less than 2 multiplied by the Welch bound. For another example, when the factorization of the total number of subcarriers includes 2, 3 and 5, the mutual coherence may be less than 4 multiplied by the Welch bound.

[0278] In summary, in order to increase the accuracy of channel estimation for low-overhead solutions (especially in Massive or Ultra Massive MIMO systems), thereby increasing the capacity of the MIMO systems, the present disclosure provides a quasi-random sampling pattern based on interleaving for signal recovery using compressed sensing algorithms.

[0279] It should be noted that, the foregoing mentioned QPP interleaved pilot locations can be used to enhance Carrier Frequency Offset estimators. The foregoing mentioned scheme can also be used in Wi-Fi channel estimation, or be used in broadcasting services that use OFDM modulation, for example digital video broadcasting-Terrestrial 2 (DVB-T2) systems.

[0280] Next, embodiments of products related to the wireless communication methods will be described.

[0281] FIG. 20 shows a schematic structural diagram of a wireless communication apparatus according to one or more embodiments of the present disclosure. As shown in FIG. 20, the wireless communication apparatus 2000 may include: a first receiving module 2002, configured to receive first information, where the first information is used for determining first frequency resource units for carrying at least one first sequence in a first frequency resource, and a reference signal corresponding to the at least one first sequence is used for measuring a channel over the first frequency resource; where the first frequency resource units in the first frequency resource are determined based on interleaving of second frequency resource units, and the second frequency resource units belong to the first frequency resource.

[0282] In a possible implementation, at least one parameter of the interleaving is associated with a total number of resource elements (REs) included in the first frequency resource.

[0283] In a possible implementation, positions of the second frequency resource units are associated with a type of the interleaving.

[0284] In a possible implementation, the interleaving includes appliance of at least one of a cubic permutation polynomial (CPP) interleaver, a quadratic permutation polynomial (QPP) interleaver, a Takeshita-Costello interleaver, a Welch-Costas interleaver, an interleaver based on a pseudonoise (PN) sequence or an interleaver based on a random integer sequence.

[0285] In a possible implementation, the interleaving includes appliance of the QPP interleaver; where the interleaving is based on a first coefficient and a second coefficient, the first coefficient and the second coefficient are used for determining a sampling pattern of all frequency resource units in the first frequency resource.

[0286] In a possible implementation, the first coefficient and the second coefficient are used for obtaining a one-to-one correspondence between positions of the second frequency resource unitsand positions of the first frequency resource units.

[0287] In a possible implementation, a first factorization of the first coefficient is represented as a product of multiple first integers and an interleaving factor, where the interleaving factor is an integer not divisible by any one of the multiple first integers, and each of the multiple first integers is a prime number.

[0288] In a possible implementation, a second factorization of a total number of resource elements in the first frequency resource is represented as a product of the multiple first integers with multiple first powers corresponding to the multiple first integers respectively, and at least one of the first powers is greater than one; where the second coefficient is not divisible by any one of the multiple first integers.

[0289] In a possible implementation, the first coefficient and the second coefficient are predefined, or, the first information indicates the first coefficient and the second coefficient.

[0290] In a possible implementation, the first coefficient and the second coefficient are determined based on a table.

[0291] In a possible implementation, at least one first frequency resource unit of the first frequency resource units includes multiple resource elements; a position of a third frequency resource unit on a second frequency resource is determined based on the QPP interleaver and a position of the at least one first frequency resource unit, where the second frequency resource and the first frequency resource are on different symbols, and the third frequency resource unit is used for carrying at least one second sequence.

[0292] In a possible implementation, the interleaving includes appliance of the interleaver based on the PN sequence, the total number of resource elements in the first frequency resource is equal to a power of two.

[0293] In a possible implementation, the first information further indicates the second frequency resource units.

[0294] In a possible implementation, the first information includes a bitmap for indicating the second frequency resource units.

[0295] In a possible implementation, at least one of first frequency resource units includes multiple resource elements, or, each of the first frequency resource units includes one resource element.

[0296] In a possible implementation, the apparatus further includes a first transmitting module, configured to transmit the at least one first sequence over the first frequency resource.

[0297] In a possible implementation, the reference signal corresponding to the at least one first sequence is a sounding reference signal (SRS) or a demodulation reference signal (DMRS).

[0298] In a possible implementation, the apparatus further includes a second receiving module 2004, configured to receive the at least one first sequence over the first frequency resource, where the reference signal corresponding to the at least one first sequence is a channel state information reference signal (CSI-RS).

[0299] In a possible implementation, the first information is carried in at least one of MAC control element (MAC CE), downlink control information (DCI) or radio resource control (RRC).

[0300] In a possible implementation, the apparatus further includes a third receiving module 2006, configured to receive second information, where the second information is used for determining fourth frequency resource units for carrying at least one third sequence in a third frequency resource, and a reference signal corresponding to the at least one third sequence is used for measuring a channel over the third frequency resource; where the first frequency resource units and the fourth frequency resource units are non-overlapping in a frequency domain.

[0301] It should be noted that, the first receiving module, the second receiving module and the third receiving module are only illustrative for their functions, in practice, the functions of the first receiving module, the second receiving module and the third receiving module may be implemented by one receiving module, which is not limited here. It should also be noted that, the functions of the receiving modules and the first transmitting module may also be implemented by a transceiving module.

[0302] The wireless communication apparatus may be applied to the first network element as described in the above method embodiments or may be the first network element as described in the above method embodiments. It should be understood by a person skilled in the art that, the relevant description of the above modules in the embodiments of the present disclosure may be understood with reference to the relevant description of the wireless communication method in the embodiments of the present disclosure.

[0303] FIG. 21 shows a schematic structural diagram of another wireless communication apparatus according to one or more embodiments of the present disclosure. As shown in FIG. 21,the wireless communication apparatus 2100 may include: a first transmitting module 2102, configured to transmit first information, where the first information is used for determining first frequency resource units for carrying at least one first sequence in a first frequency resource, and a reference signal corresponding to the at least one first sequence is used for measuring a channel over the first frequency resource; where the first frequency resource units in the first frequency resource are determined based on interleaving of second frequency resource units, and the second frequency resource units belong to the first frequency resource.

[0304] In a possible implementation, at least one parameter of the interleaving is associated with a total number of resource elements (REs) included in the first frequency resource.

[0305] In a possible implementation, positions of the second frequency resource units are associated with a type of the interleaving.

[0306] In a possible implementation, the interleaving includes appliance of at least one of a cubic permutation polynomial (CPP) interleaver, a quadratic permutation polynomial (QPP) interleaver, a Takeshita-Costello interleaver, a Welch-Costas interleaver, an interleaver based on a pseudonoise (PN) sequence or an interleaver based on a random integer sequence.

[0307] In a possible implementation, the interleaving includes appliance of the QPP interleaver; where the interleaving is based on a first coefficient and a second coefficient, the first coefficient and the second coefficient are used for determining a time domain pattern of all frequency resource units in the first frequency resource.

[0308] In a possible implementation, the first coefficient and the second coefficient are used for obtaining a one-to-one correspondence between positions of the second frequency resource units and positions of the first frequency resource units.

[0309] In a possible implementation, a first factorization of the first coefficient is represented as a product of multiple first integers and an interleaving factor, where the interleaving factor is an integer not divisible by any one of the multiple first integers, and each of the multiple first integers is a prime number.

[0310] In a possible implementation, a second factorization of a total number of resource elements in the first frequency resource is represented as a product of the multiple first integers with multiple first powers corresponding to the multiple first integers respectively, and at least oneof the first powers is greater than one; wherein the second coefficient is not divisible by any one of the multiple first integers.

[0311] In a possible implementation, the first coefficient and the second coefficient are predefined, or, the first information indicates the first coefficient and the second coefficient.

[0312] In a possible implementation, the first coefficient and the second coefficient are determined based on a table.

[0313] In a possible implementation, at least one first frequency resource unit of the first frequency resource units includes multiple resource elements; a position of a third frequency resource unit on a second frequency resource is determined based on the QPP interleaver and a position of the at least one first frequency resource unit, where the second frequency resource and the first frequency resource are on different symbols, and the third frequency resource unit is used for carrying at least one second sequence.

[0314] In a possible implementation, the interleaving includes appliance of the interleaver based on the PN sequence, the total number of resource elements in the first frequency resource is equal to a power of two.

[0315] In a possible implementation, the first information further indicates the second frequency resource units.

[0316] In a possible implementation, the first information includes a bitmap for indicating the second frequency resource units.

[0317] In a possible implementation, at least one of first frequency resource units includes multiple resource elements, or, each of the first frequency resource units includes one resource element.

[0318] In a possible implementation, the apparatus further includes a first receiving module, configured to receive the at least one first sequence over the first frequency resource.

[0319] In a possible implementation, the reference signal corresponding to the at least one first sequence is a sounding reference signal (SRS) or a demodulation reference signal (DMRS).

[0320] In a possible implementation, the apparatus further includes a second transmitting module 2104, configured to transmit the at least one first sequence over the first frequency resource, where the reference signal corresponding to the at least one first sequence is a channel state information reference signal (CSI-RS).

[0321] In a possible implementation, the first information is carried in at least one of MAC control element (MAC CE), downlink control information (DCI) or radio resource control (RRC).

[0322] In a possible implementation, the apparatus further includes a third transmitting module 2106, configured to transmit second information, where the second information is used for determining fourth frequency resource units for carrying at least one third sequence in a third frequency resource, and a reference signal corresponding to the at least one third sequence is used for measuring a channel over the third frequency resource; where the first frequency resource units and the fourth frequency resource units are non-overlapping in a frequency domain.

[0323] It should be noted that, the first transmitting module, the second transmitting module and the third transmitting module are only illustrative for their functions, in practice, the functions of the first transmitting module, the second transmitting module and the third transmitting module may be implemented by one transmitting module, which is not limited here. It should also be noted that, the functions of the transmitting modules and the first receiving module may also be implemented by a transceiving module.

[0324] The wireless communication apparatus may be applied to the second network element as described in the above method embodiments or may be the second network element as described in the above method embodiments. It should be understood by a person skilled in the art that, the relevant description of the above modules in the embodiments of the present disclosure may be understood with reference to the relevant description of the wireless communication method in the embodiments of the present disclosure.

[0325] FIG. 22 is a schematic structural diagram of a wireless communication apparatus according to one or more embodiments of the present disclosure, the apparatus may be a second network element or a first network element. As shown in FIG. 22, the wireless communication apparatus 2200 includes a processor 2202, an interface 2204 for communicating with other devices, and a memory 2206. The memory 2206 may be stored with computer execution instructions, and the processor 2202 executes computer execution instructions stored in the memory 2206 to enable the apparatus to execute any of the above wireless communication methods.

[0326] In some aspects of the present disclosure, there is provided a first network element including processing circuitry for executing any of the above wireless communication methods. It should be understood that the first network element can execute the steps performed by the firstnetwork element in the above method embodiments, which will not be repeated here.

[0327] In some aspects of the present disclosure, there is provided a second network element including processing circuitry for executing any of the above wireless communication methods. It should be understood that the second network element can execute the steps performed by the second network element in the above method embodiments, which will not be repeated here.

[0328] In some aspects of the present disclosure, there is provided a wireless communication apparatus which includes a processor and a memory. The memory is storing instructions that cause the processor to perform any of the above wireless communication methods.

[0329] In some aspects of the present disclosure, there is provided a wireless communication system, including a second network element and a first network element. The second network element is configured to execute the steps executed by the second network element in any of the above wireless communication methods, and the first network element is configured to execute the steps executed by the first network element in any of the above wireless communication methods.

[0330] In some aspects of the present disclosure, there is provided a chip, including an input / output (I / O) interface and a processor, where the processor is configured to call and run computer execution instructions stored in a memory, to enable a device installing with the chip to execute any of the above wireless communication methods.

[0331] In some aspects of the present disclosure, there is provided a computer-readable medium storing computer execution instructions which, when executed by a processor, causes the processor to execute any of the above wireless communication methods.

[0332] In some aspects of the present disclosure, there is provided a computer program product including computer execution instructions which, when executed by a processor, causes the processor to execute any of the above wireless communication methods.

[0333] Although the present disclosure describes methods and processes with steps in a certain order, one or more steps of the methods and processes may be omitted or altered as appropriate. One or more steps may take place in an order other than that in which they are described, as appropriate.

[0334] Note that the expression “at least one of A or B”, as used herein, is interchangeable with the expression “A and / or B”. It refers to a list in which you may select A or B or both A and B.Similarly, “at least one of A, B, or C”, as used herein, is interchangeable with “A and / or B and / or C” or “A, B, and / or C”. It refers to a list in which you may select: A or B or C, or both A and B, or both A and C, or both B and C, or all of A, B and C. The same principle applies for longer lists having a same format.

[0335] Although the present disclosure is described, at least in part, in terms of methods, a person of ordinary skill in the art will understand that the present disclosure is also directed to the various components for performing at least some of the aspects and features of the described methods, be it by way of hardware components, software or any combination of the two. Accordingly, the technical solution of the present disclosure may be embodied in the form of a software product. A suitable software product may be stored in a pre-recorded storage device or other similar nonvolatile or non-transitory computer readable medium, including DVDs, CD-ROMs, USB flash disk, a removable hard disk, or other storage media, for example. The software product includes instructions tangibly stored thereon that enable a processing device (e.g., a personal computer, a server, or a network device) to execute examples of the methods disclosed herein. The machineexecutable instructions may be in the form of code sequences, configuration information, or other data, which, when executed, cause a machine (e.g., a processor or other processing device) to perform steps in a method according to examples of the present disclosure.

[0336] The present disclosure may be embodied in other specific forms without departing from the subject matter of the claims. The described example embodiments are to be considered in all respects as being only illustrative and not restrictive. Selected features from one or more of the above-described embodiments may be combined to create alternative embodiments not explicitly described, features suitable for such combinations being understood within the scope of this disclosure.

[0337] All values and sub-ranges within disclosed ranges are also disclosed. Also, although the systems, devices and processes disclosed and shown herein may include a specific number of elements / components, the systems, devices and assemblies could be modified to include additional or fewer of such elements / components. For example, although any of the elements / components disclosed may be referenced as being singular, the embodiments disclosed herein could be modified to include a plurality of such elements / components. The subject matter described herein intends to cover and embrace all suitable changes in technology.

[0338] Although embodiments have been described above with reference to the accompanying drawings, those of skill in the art will appreciate that variations and modifications may be made without departing from the scope thereof as defined by the appended claims.

Claims

CLAIMS1. A wireless communication method, comprising: receiving first information, wherein the first information is used for determining first frequency resource units for carrying at least one first sequence in a first frequency resource, and a reference signal corresponding to the at least one first sequence is used for measuring a channel over the first frequency resource; wherein the first frequency resource units in the first frequency resource are determined based on interleaving of second frequency resource units, and the second frequency resource units belong to the first frequency resource.

2. The method according to claim 1, wherein at least one parameter of the interleaving is associated with a total number of resource elements (REs) comprised in the first frequency resource.

3. The method according to claim 1 or 2, wherein positions of the second frequency resource units are associated with a type of the interleaving.

4. The method according to any one of claims 1 to 3, wherein the interleaving comprises appliance of at least one of a cubic permutation polynomial (CPP) interleaver, a quadratic permutation polynomial (QPP) interleaver, a Takeshita-Costello interleaver, a Welch-Costas interleaver, an interleaver based on a pseudo-noise (PN) sequence or an interleaver based on a random integer sequence.

5. The method according to claim 4, wherein the interleaving comprises appliance of the QPP interleaver; wherein the interleaving is based on a first coefficient and a second coefficient, the first coefficient and the second coefficient is used for determining a sampling pattern of all frequency resource units in the first frequency resource.

6. The method according to claim 5, wherein the first coefficient and the second coefficient are used for obtaining a one-to-one correspondence between positions of the second frequency resource units and positions of the first frequency resource units.

7. The method according to claim 5 or 6, wherein a first factorization of the first coefficientis represented as a product of multiple first integers and an interleaving factor, wherein the interleaving factor is an integer not divisible by any one of the multiple first integers, and each of the multiple first integers is a prime number.

8. The method according to claim 7, wherein a second factorization of a total number of resource elements in the first frequency resource is represented as a product of the multiple first integers with multiple first powers corresponding to the multiple first integers respectively, and at least one of the first powers is greater than one; wherein the second coefficient is not divisible by any one of the multiple first integers.

9. The method according to any one of claims 6 to 8, wherein the first coefficient and the second coefficient are predefined, or, wherein the first information indicates the first coefficient and the second coefficient.

10. The method according to claim 9, wherein the first coefficient and the second coefficient are determined based on a table.

11. The method according to any one of claims 5 to 10, wherein at least one first frequency resource unit of the first frequency resource units comprises multiple resource elements; a position of a third frequency resource unit on a second frequency resource is determined based on the QPP interleaver and a position of the at least one first frequency resource unit, wherein the second frequency resource and the first frequency resource are on different symbols, and the third frequency resource unit is used for carrying at least one second sequence.

12. The method according to claim 4, wherein the interleaving comprises appliance of the interleaver based on the PN sequence, the total number of resource elements in the first frequency resource is equal to a power of two.

13. The method according to any one of claims 1 to 12, wherein the first information further indicates the second frequency resource units.

14. The method according to claim 13, wherein the first information comprises a bitmap for indicating the second frequency resource units.

15. The method according to any one of claims 1 to 14, wherein at least one of first frequency resource units comprises multiple resource elements, or, wherein each of the first frequency resource units comprises one resource element.

16. The method according to any one of claims 1 to 15, further comprising:transmitting the at least one first sequence over the first frequency resource.

17. The method according to claim 16, wherein the reference signal corresponding to the at least one first sequence is a sounding reference signal (SRS) or a demodulation reference signal (DMRS).

18. The method according to any one of claims 1 to 15, further comprising: receiving the at least one first sequence over the first frequency resource, wherein the reference signal corresponding to the at least one first sequence is a channel state information reference signal (CSI-RS).

19. The method according to any one of claims 1 to 18, wherein the first information is carried in at least one of MAC control element (MAC CE), downlink control information (DCI) or radio resource control (RRC).

20. The method according to any one of claims 1 to 19, further comprising: receiving second information, wherein the second information is used for determining fourth frequency resource units for carrying at least one third sequence in a third frequency resource, and a reference signal corresponding to the at least one third sequence is used for measuring a channel over the third frequency resource; wherein the first frequency resource units and the fourth frequency resource units are nonoverlapping in a frequency domain.

21. A wireless communication method, comprising: transmitting first information, wherein the first information is used for determining first frequency resource units for carrying at least one first sequence in a first frequency resource, and a reference signal corresponding to the at least one first sequence is used for measuring a channel over the first frequency resource; wherein the first frequency resource units in the first frequency resource are determined based on interleaving of second frequency resource units, and the second frequency resource units belong to the first frequency resource.

22. The method according to claim 21, wherein at least one parameter of the interleaving is associated with a total number of resource elements (REs) comprised in the first frequency resource.

23. The method according to claim 21 or 22, wherein positions of the second frequencyresource units are associated with a type of the interleaving.

24. The method according to any one of claims 21 to 23, wherein the interleaving comprises appliance of at least one of a cubic permutation polynomial (CPP) interleaver, a quadratic permutation polynomial (QPP) interleaver, a Takeshita-Costello interleaver, a Welch-Costas interleaver, an interleaver based on a pseudo-noise (PN) sequence or an interleaver based on a random integer sequence.

25. The method according to claim 24, wherein the interleaving comprises appliance of the QPP interleaver; wherein the interleaving is based on a first coefficient and a second coefficient, and the first coefficient and the second coefficient are used for determining a time domain pattern of all frequency resource units in the first frequency resource.

26. The method according to claim 25, wherein the first coefficient and the second coefficient are used for obtaining a one-to-one correspondence between positions of the second frequency resource units and positions of the first frequency resource units.

27. The method according to claim 25 or 26, wherein a first factorization of the first coefficient is represented as a product of multiple first integers and an interleaving factor, wherein the interleaving factor is an integer not divisible by any one of the multiple first integers, and each of the multiple first integers is a prime number.

28. The method according to claim 27, wherein a second factorization of a total number of resource elements in the first frequency resource is represented as a product of the multiple first integers with multiple first powers corresponding to the multiple first integers respectively, and at least one of the first powers is greater than one; wherein the second coefficient is not divisible by any one of the multiple first integers.

29. The method according to any one of claims 26 to 28, wherein the first coefficient and the second coefficient are predefined, or, wherein the first information indicates the first coefficient and the second coefficient.

30. The method according to claim 29, wherein the first coefficient and the second coefficient are determined based on a table.

31. The method according to any one of claims 25 to 30, wherein at least one first frequency resource unit of the first frequency resource units comprises multiple resource elements;a position of a third frequency resource unit on a second frequency resource is determined based on the QPP interleaver and a position of the at least one first frequency resource unit, wherein the second frequency resource and the first frequency resource are on different symbols, and the third frequency resource unit is used for carrying at least one second sequence.

32. The method according to claim 24, wherein the interleaving comprises appliance of the interleaver based on the PN sequence, the total number of resource elements in the first frequency resource is equal to a power of two.

33. The method according to any one of claims 21 to 32, wherein the first information further indicates the second frequency resource units.

34. The method according to claim 33, wherein the first information comprises a bitmap for indicating the second frequency resource units.

35. The method according to any one of claims 21 to 34, wherein at least one of first frequency resource units comprises multiple resource elements, or, wherein each of the first frequency resource units comprises one resource element.

36. The method according to any one of claims 21 to 35, further comprising: receiving the at least one first sequence over the first frequency resource.

37. The method according to claim 36, wherein the reference signal corresponding to the at least one first sequence is a sounding reference signal (SRS) or a demodulation reference signal (DMRS).

38. The method according to any one of claims 21 to 35, further comprising: transmitting the at least one first sequence over the first frequency resource, wherein the reference signal corresponding to the at least one first sequence is a channel state information reference signal (CSI-RS).

39. The method according to any one of claims 21 to 38, wherein the first information is carried in at least one of MAC control element (MAC CE), downlink control information (DCI) or radio resource control (RRC).

40. The method according to any one of claims 21 to 39, further comprising: transmitting second information, wherein the second information is used for determining fourth frequency resource units for carrying at least one third sequence in a third frequency resource, and a reference signal corresponding to the at least one third sequence is used formeasuring a channel over the third frequency resource; wherein the first frequency resource units and the fourth frequency resource units are nonoverlapping in a frequency domain.

41. A wireless communication apparatus, comprising modules for performing the method according to any one of claims 1 to 20.

42. A wireless communication apparatus, comprising modules for performing the method according to any one of claims 21 to 40.

43. A computer-readable medium storing computer execution instructions which, when executed by a processor, causes the processor to execute the method according to any one of claims 1 to 20 or the method according to any one of claims 21 to 40.

44. A computer program product comprising computer execution instructions which, when executed by a processor, causes the processor to execute the method according to any one of claims 1 to 20 or the method according to any one of claims 21 to 40.

45. A chip, comprising an input / output (I / O) interface and a processor, wherein the processor is configured to call and run computer execution instructions stored in a memory, to enable a device installing with the chip to execute the method according to any one of claims 1 to 20 or the method according to any one of claims 21 to 40.

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