Method, apparatus and computer program

Abstract

There is provided an apparatus comprising means for mapping frequency domain symbols on a plurality of subcarriers into at least two sets, each set comprising symbols of at least one of the plurality of subcarriers; for each set: performing a symbol-by-symbol rotation based on a multiple coefficient value, and converting the rotated symbols from the frequency domain to the time domain; or converting the symbols from the frequency domain to the time domain, and performing symbol-by-symbol rotation on the time domain symbols based on the multiple coefficient value; inserting a cyclic prefix in each time domain symbol; linking the time domain symbols generated by the cyclic prefix insertion to generate a sub-band waveform; and performing sub-band filtering, interpolation, and combination based on the sub-band waveforms of each of the sets to generate a single waveform.

Description

Technical Field

[0001] The present application relates to a method, apparatus, system and computer program, particularly but not limited to waveform generation. Background Art

[0002] A communication system can be viewed as a facility that enables a communication session between two or more entities (such as user terminals, base stations and / or other nodes) by providing a carrier between the various entities involved in the communication path. A communication system can be provided, for example, by a communication network and one or more compatible communication devices. A communication session may include, for example, a communication for carrying data for communication, such as voice, video, electronic mail (email), text message, multimedia and / or content data, etc. Non-limiting examples of the services provided include two-way or multi-way calls, data communications or multimedia services, and access to a data network system (such as the Internet).

[0003] In a wireless communication system, at least a portion of a communication session between at least two stations is conducted over a wireless link. Examples of wireless systems include public land mobile networks (PLMNs), satellite-based communication systems, and different wireless local area networks, such as wireless local area networks (WLANs). Some wireless systems can be divided into cells and are therefore often referred to as cellular systems.

[0004] A user may access a communication system through an appropriate communication device or terminal. The user's communication device may be referred to as a user equipment (UE) or user device. The communication device is provided with appropriate signal receiving and sending means for enabling communication, for example, enabling access to a communication network or direct communication with other users. The communication device may access a carrier provided by a station (e.g., a base station of a cell) and send and / or receive communications on the carrier.

[0005] A communication system and associated equipment typically operate according to a given standard or specification, which specifies what the various entities associated with the system are allowed to do and how it should be implemented. Communication protocols and / or parameters for the connection are also typically defined. An example of a communication system is UTRAN (3G radio). Other examples of communication systems are the Long Term Evolution (LTE) of the Universal Mobile Telecommunications System (UMTS) radio access technology and the so-called 5G or New Radio (NR) networks. NR is being standardized by the Third Generation Partnership Project (3GPP). Another example of a communication system is the so-called 6G network. Summary of the invention

[0006] According to one aspect, a device is provided, the device including components for: mapping frequency domain symbols on multiple subcarriers into at least two sets, each set including symbols of at least one subcarrier among the multiple subcarriers; for each set: performing symbol-by-symbol rotation based on complex coefficient values, and converting the rotated symbols from the frequency domain to the time domain; or converting the symbols from the frequency domain to the time domain, and performing symbol-by-symbol rotation on the time domain symbols based on the complex coefficient values; inserting a cyclic prefix in each time domain symbol; connecting the time domain symbols generated by the cyclic prefix insertion to generate a subband waveform; and performing subband filtering, interpolation, and combination based on the subband waveforms of each set in the set to generate a single waveform.

[0007] The two or more sets may include one or more active sets and one or more inactive sets, wherein the one or more active sets may contain mapped frequency domain symbols, and wherein the one or more inactive sets may not contain mapped frequency domain symbols.

[0008] Converting the rotated symbols from the frequency domain to the time domain may include applying an inverse fast Fourier transform to each of the rotated symbols.

[0009] The complex coefficient value can be φ m，b =exp(-2jπθ m，b ),in:

[0010]

[0011] L is the number of subcarriers,

[0012] M is the number of sets,

[0013] b is the index of the symbol,

[0014] m is the index of the collection and is an integer value ranging from 0 to M-1, and

[0015] N CP,k is the length of the cyclic prefix.

[0016] Performing subband filtering, interpolation, and combining based on subband waveforms to generate a single waveform may include: for each set: modulating the subband waveform to a first frequency; interpolating the modulated subband waveform; and modulating the interpolated modulated subband waveform to a second frequency; and combining the resulting interpolated and modulated subband waveforms of each set into a single waveform.

[0017] The first frequency may be c m / M, where: M is the number of sets; and c m is an implementation specific parameter used to control the spectrum of the subband waveform.

[0018] The second frequency may be fm =f SCS L / M[(M-1) / 2-m]-c m , where: f SCS is the subcarrier spacing frequency of the generated waveform; L is the number of subcarriers, M is the number of sets, m is the set number and is an integer value varying between 0 and M-1, and c m is an implementation specific parameter used to control the spectrum of the subband waveform.

[0019] Interpolation may include upsampling and filtering the modulated sub-band waveform.

[0020] Upsampling may include inserting a certain number of zeros between samples of the modulated sub-band waveform.

[0021] Performing subband filtering, interpolation and combination based on the subband waveform to generate a waveform may include: for each set: dividing the symbols of the subband waveform into multiple overlapping blocks; converting the multiple overlapping blocks to the frequency domain; applying a window function to each overlapping block in the overlapping blocks in the frequency domain to generate multiple windowed blocks; converting the multiple windowed blocks from the frequency domain to the time domain; and discarding a subset of each windowed block in the multiple windowed blocks in the time domain; and combining the resulting time domain windowed blocks of each set in the set into a single waveform.

[0022] For each set, the size Po of the overlapping block may be smaller than the size P of the block.

[0023] The number of discarded samples may be Qo=PoM, where M is the number of sets.

[0024] Performing subband filtering, interpolation, and combining based on subband waveforms to generate waveforms may include: for each set: converting the subband waveform from serial to parallel, wherein the resulting parallel components of the subband waveform are at least partially overlapped; converting multiple at least partially overlapping parallel components of the subband waveform into the frequency domain; applying a window function to the frequency domain parallel overlapping components of the subband waveform; removing overlapping blocks from the windowed frequency domain parallel overlapping components of the subband waveform, and converting the resulting parallel components into a serial subband waveform; interpolating the serial subband waveform; and modulating the interpolated serial subband waveform to a third frequency; and combining the resulting modulated interpolated serial subband waveforms of each set into a single waveform.

[0025] The third frequency may be f m =f SCS L / M[(M-1) / 2-m], where: f SCS is the subcarrier spacing frequency of a single waveform; L is the number of subcarriers, M is the number of sets, and m is the number of the set and is an integer value varying between 0 and M-1.

[0026] Interpolation may include upsampling and filtering the modulated sub-band waveform.

[0027] Upsampling may include inserting a certain number of zeros between samples of the modulated sub-band waveform.

[0028] The component may also be configured to perform a discrete Fourier transform on the time domain symbols prior to mapping to generate frequency domain symbols to be mapped onto a plurality of subcarriers.

[0029] According to one aspect, an apparatus is provided that includes components for: separating a single waveform into two or more subband waveforms; for each subband waveform: converting the subband waveform into multiple time domain symbol sequences; removing a cyclic prefix from each of the multiple time domain symbol sequences; converting each of the resulting multiple symbols from the time domain to the frequency domain; performing a symbol-by-symbol rotation on the frequency domain symbols based on a complex coefficient value; and mapping the rotated frequency domain symbols derived from each subband waveform into a single set including multiple rotated frequency domain symbols on multiple subcarriers.

[0030] Converting the plurality of symbols from the time domain to the frequency domain may include applying a fast Fourier transform to each symbol of the plurality of symbols.

[0031] The complex coefficient value can be φ m，b =exp(+2jπθ m，b ),in:

[0032]

[0033] L is the number of subcarriers,

[0034] M is the number of sets,

[0035] b is the index of the symbol,

[0036] m is the index of the collection and is an integer value ranging from 0 to M-1, and

[0037] N CP,k is the length of the cyclic prefix.

[0038] The component may be configured to: for each sub-band waveform: demodulate the sub-band waveform from the second frequency; extract the demodulated sub-band waveform; demodulate the extracted demodulated sub-band waveform from the first frequency; and convert the obtained sub-band waveform into a plurality of time domain symbol sequences.

[0039] The first frequency may be c m / M, where: M is the number of sets; and c m is an implementation specific parameter used to enhance the portion of the spectrum of the sub-band waveform.

[0040] The second frequency may be fm =f SCS L / M[(M-1) / 2-m]-c m , where: f SCS is the subcarrier spacing frequency of a single waveform; L is the number of subcarriers, M is the number of sets, m is the set number and is an integer value varying between 0 and M-1, and c m is an implementation specific parameter used to enhance the portion of the spectrum of the sub-band waveform.

[0041] Decimation may include filtering and downsampling the demodulated sub-band waveforms.

[0042] Downsampling may include removing a certain number of samples from the samples of the demodulated sub-band waveform.

[0043] Separating a single waveform into two or more sub-band waveforms may include: dividing the single waveform into multiple partially overlapping blocks including one or more time domain symbols; converting each partially overlapping time domain symbol block to the frequency domain; dividing the resulting frequency domain symbols into multiple partially overlapping frequency domain symbol sets; and for each set: applying a window function to the frequency domain symbol set; converting the windowed frequency domain symbol set to the time domain; removing the overlapping portions from each partially overlapping time domain symbol set, and combining the resulting symbols into sub-band waveforms.

[0044] For each sub-band waveform, the size Po of the overlapped block may be smaller than the size P of the block.

[0045] Separating a single waveform into two or more sub-band waveforms may include: for each sub-band waveform: demodulating the sub-band waveform from a third frequency; extracting the demodulated sub-band waveform; separating the extracted demodulated sub-band waveform into a plurality of partially overlapping symbol blocks, wherein each symbol block at least partially overlaps with at least one other symbol block; and for each block: converting the partially overlapping symbol block to the frequency domain; applying a window function to the frequency domain partially overlapping symbol block; converting the resulting frequency domain partially overlapping symbol block to the time domain; and removing overlapping symbols from each time domain partially overlapping symbol block, and combining the resulting symbols into a sub-band waveform.

[0046] The third frequency may be f m =f SCS L / M[(M-1) / 2-m], where: f SCS is the subcarrier spacing frequency of a single waveform; L is the number of subcarriers, M is the number of sets, and m is the number of the set and is an integer value varying between 0 and M-1.

[0047] Decimation may include filtering and downsampling the modulated sub-band waveform.

[0048] Downsampling may include removing a certain number of samples from the samples of the modulated sub-band waveform.

[0049] The component may also be used to perform an inverse discrete Fourier transform on the mapped symbols to generate a plurality of time domain symbols on a plurality of subcarriers.

[0050] According to one aspect, a device is provided, which includes at least one processor and at least one memory storing instructions, which, when executed by the at least one processor, causes the device to at least: map frequency domain symbols on multiple subcarriers into at least two sets, each set including symbols of at least one subcarrier among the multiple subcarriers; for each set: perform symbol-by-symbol rotation based on complex coefficient values, and convert the rotated symbols from the frequency domain to the time domain; or convert the symbols from the frequency domain to the time domain, and perform symbol-by-symbol rotation on the time domain symbols based on the complex coefficient values; insert a cyclic prefix into each time domain symbol; connect the time domain symbols generated by the cyclic prefix insertion to generate a subband waveform; and perform subband filtering, interpolation, and combination based on the subband waveforms of each set in the set to generate a single waveform.

[0051] The two or more sets may include one or more active sets and one or more inactive sets, wherein the one or more active sets may contain mapped frequency domain symbols, and wherein the one or more inactive sets may not contain mapped frequency domain symbols.

[0052] The at least one processor may further cause the apparatus to apply an inverse fast Fourier transform to each of the rotated symbols.

[0053] The complex coefficient value can be φ m，b =exp(-2jπθ m，b ),in:

[0054]

[0055] L is the number of subcarriers,

[0056] M is the number of sets,

[0057] b is the index of the symbol,

[0058] m is the index of the collection and is an integer value ranging from 0 to M-1, and

[0059] N CP,k is the length of the cyclic prefix.

[0060] At least one processor may also cause the apparatus to: for each set: modulate the subband waveform to a first frequency; interpolate the modulated subband waveform; and modulate the interpolated modulated subband waveform to a second frequency; and combine the resulting interpolated and modulated subband waveforms of each set into a single waveform.

[0061] The first frequency may be c m / M, where: M is the number of sets; and c m is an implementation specific parameter used to control the spectrum of the subband waveform.

[0062] The second frequency may be f m =f SCS L / M[(M-1) / 2-m]-c m , where: f SCS is the subcarrier spacing frequency of the generated waveform; L is the number of subcarriers, M is the number of sets, m is the set number and is an integer value varying between 0 and M-1, and c m is an implementation specific parameter used to control the spectrum of the subband waveform.

[0063] The at least one processor may further cause the apparatus to upsample and filter the modulated sub-band waveform.

[0064] The at least one processor may further cause the apparatus to insert a number of zeros between samples of the modulated sub-band waveform.

[0065] At least one processor can also cause the device to: for each set: split the symbols of the subband waveform into multiple overlapping blocks; convert the multiple overlapping blocks to the frequency domain; apply a window function to each overlapping block in the frequency domain to generate multiple windowed blocks; convert the multiple windowed blocks from the frequency domain to the time domain; and discard a subset of each windowed block in the multiple windowed blocks in the time domain; and combine the resulting time domain windowed blocks of each set in the set into a single waveform.

[0066] For each set, the size Po of the overlapping block may be smaller than the size P of the block.

[0067] The number of discarded samples may be Qo=PoM, where M is the number of sets.

[0068] At least one processor may also cause the apparatus to: for each set: convert a subband waveform from serial to parallel, wherein the resulting parallel components of the subband waveform are at least partially overlapped; convert multiple at least partially overlapping parallel components of the subband waveform into the frequency domain; apply a window function to the frequency domain parallel overlapping components of the subband waveform; remove overlapping blocks from the windowed frequency domain parallel overlapping components of the subband waveform, and convert the resulting parallel components into a serial subband waveform; interpolate the serial subband waveform; and modulate the interpolated serial subband waveform to a third frequency; and combine the resulting modulated interpolated serial subband waveforms of each set into a single waveform.

[0069] The third frequency may be f m =f SCS L / M[(M-1) / 2-m], where: f SCS is the subcarrier spacing frequency of a single waveform; L is the number of subcarriers, M is the number of sets, and m is the number of the set and is an integer value varying between 0 and M-1.

[0070] The at least one processor may further cause the apparatus to upsample and filter the modulated sub-band waveform.

[0071] The at least one processor may further cause the apparatus to insert a number of zeros between samples of the modulated sub-band waveform.

[0072] The at least one processor may further cause the apparatus to: perform a discrete Fourier transform on the time-domain symbols before mapping to generate frequency-domain symbols to be mapped onto the plurality of subcarriers.

[0073] According to one aspect, a device is provided, the device comprising at least one processor and at least one memory storing instructions, which, when executed by the at least one processor, causes the device to at least: separate a single waveform into two or more sub-band waveforms; for each sub-band waveform: convert the sub-band waveform into multiple time domain symbol sequences; remove a cyclic prefix from each of the multiple time domain symbol sequences; convert each of the resulting multiple symbols from the time domain to the frequency domain; perform a symbol-by-symbol rotation on the frequency domain symbols based on a complex coefficient value; and map the rotated frequency domain symbols derived from each sub-band waveform into a single set including multiple rotated frequency domain symbols on multiple subcarriers.

[0074] The at least one processor may further cause the apparatus to apply a fast Fourier transform to each symbol of the plurality of symbols.

[0075] The complex coefficient value can be φ m,b =exp(+2jπθ m,b ),in:

[0076]

[0077] L is the number of subcarriers,

[0078] M is the number of sets,

[0079] b is the index of the symbol,

[0080] m is the index of the collection and is an integer value ranging from 0 to M-1, and

[0081] N CP,k is the length of the cyclic prefix.

[0082] The at least one processor may further cause the apparatus to: for each sub-band waveform: demodulate the sub-band waveform from the second frequency; extract the demodulated sub-band waveform; demodulate the extracted demodulated sub-band waveform from the first frequency; and convert the resulting sub-band waveform into a plurality of time-domain symbol sequences.

[0083] The first frequency may be c m / M, where: M is the number of sets; and c m is an implementation specific parameter used to enhance the portion of the spectrum of the sub-band waveform.

[0084] The second frequency may be f m =f SCS L / M[(M-1) / 2-m]-c m , where: f SCS is the subcarrier spacing frequency of a single waveform; L is the number of subcarriers, M is the number of sets, m is the set number and is an integer value varying between 0 and M-1, and c m is an implementation specific parameter used to enhance the portion of the spectrum of the sub-band waveform.

[0085] The at least one processor may further cause the apparatus to filter and downsample the demodulated sub-band waveform.

[0086] The at least one processor may further cause the apparatus to remove a number of samples from the samples of the demodulated sub-band waveform.

[0087] At least one processor can also cause the device to: divide a single waveform into multiple partially overlapping blocks including one or more time domain symbols; convert each partially overlapping time domain symbol block to the frequency domain; divide the resulting frequency domain symbols into multiple partially overlapping frequency domain symbol sets; and for each set: apply a window function to the frequency domain symbol set; convert the windowed frequency domain symbol set to the time domain; remove the overlapping portions from each partially overlapping time domain symbol set, and combine the resulting symbols into a sub-band waveform.

[0088] For each sub-band waveform, the size Po of the overlapped block may be smaller than the size P of the block.

[0089] At least one processor may also cause the apparatus to: for each subband waveform: demodulate the subband waveform from a third frequency; extract the demodulated subband waveform; separate the extracted demodulated subband waveform into a plurality of partially overlapping symbol blocks, wherein each symbol block at least partially overlaps with at least one other symbol block; and for each block: convert the partially overlapping symbol block to the frequency domain; apply a window function to the frequency domain partially overlapping symbol block; convert the resulting frequency domain partially overlapping symbol block to the time domain; and remove overlapping symbols from each time domain partially overlapping symbol block, and combine the resulting symbols into a subband waveform.

[0090] The third frequency may be f m =f SCS L / M[(M-1) / 2-m], where: f SCS is the subcarrier spacing frequency of a single waveform; L is the number of subcarriers, M is the number of sets, and m is the number of the set and is an integer value varying between 0 and M-1.

[0091] The at least one processor may further cause the apparatus to filter and downsample the modulated sub-band waveform.

[0092] The at least one processor may further cause the apparatus to remove a number of samples from the samples of the modulated sub-band waveform.

[0093] The at least one processor may further cause the apparatus to perform an inverse discrete Fourier transform on the mapped symbols to generate a plurality of time domain symbols over a plurality of subcarriers.

[0094] According to one aspect, a method is provided, the method comprising: mapping frequency domain symbols on a plurality of subcarriers into at least two sets, each set comprising symbols of at least one subcarrier among the plurality of subcarriers; for each set: performing symbol-by-symbol rotation based on a complex coefficient value, and converting the rotated symbol from the frequency domain to the time domain; or converting the symbol from the frequency domain to the time domain, and performing symbol-by-symbol rotation on the time domain symbol based on the complex coefficient value; inserting a cyclic prefix into each time domain symbol; concatenating the time domain symbols generated by the cyclic prefix insertion to generate a subband waveform; and performing subband filtering, interpolation, and combining based on the subband waveform of each set in the set to generate a single waveform.

[0095] The two or more sets may include one or more active sets and one or more inactive sets, wherein the one or more active sets may contain mapped frequency domain symbols, and wherein the one or more inactive sets may not contain mapped frequency domain symbols.

[0096] Converting the rotated symbols from the frequency domain to the time domain may include applying an inverse fast Fourier transform to each of the rotated symbols.

[0097] The complex coefficient value can be φ m，b =exp(-2jπθ m，b ),in:

[0098]

[0099] L is the number of subcarriers,

[0100] M is the number of sets,

[0101] b is the index of the symbol,

[0102] m is the index of the collection and is an integer value ranging from 0 to M-1, and

[0103] N CP,k is the length of the cyclic prefix.

[0104] Performing subband filtering, interpolation, and combining based on subband waveforms to generate a single waveform may include: for each set: modulating the subband waveform to a first frequency; interpolating the modulated subband waveform; and modulating the interpolated modulated subband waveform to a second frequency; and combining the resulting interpolated and modulated subband waveforms of each set into a single waveform.

[0105] The first frequency may be c m / M, where: M is the number of sets; and c m is an implementation specific parameter used to control the spectrum of the subband waveform.

[0106] The second frequency may be f m =f SCS L / M[(M-1) / 2-m]-c m , where: f SCS is the subcarrier spacing frequency of the generated waveform; L is the number of subcarriers, M is the number of sets, m is the set number and is an integer value varying between 0 and M-1, and c m is an implementation specific parameter used to control the spectrum of the subband waveform.

[0107] Interpolation may include upsampling and filtering the modulated sub-band waveform.

[0108] Upsampling may include inserting a certain number of zeros between samples of the modulated sub-band waveform.

[0109] Performing subband filtering, interpolation and combination based on the subband waveform to generate a waveform may include: for each set: dividing the symbols of the subband waveform into multiple overlapping blocks; converting the multiple overlapping blocks to the frequency domain; applying a window function to each overlapping block in the overlapping blocks in the frequency domain to generate multiple windowed blocks; converting the multiple windowed blocks from the frequency domain to the time domain; and discarding a subset of each windowed block in the multiple windowed blocks in the time domain; and combining the resulting time domain windowed blocks of each set in the set into a single waveform.

[0110] For each set, the size Po of the overlapping block may be smaller than the size P of the block.

[0111] The number of discarded samples may be Qo=PoM, where M is the number of sets.

[0112] Performing subband filtering, interpolation, and combining based on subband waveforms to generate waveforms may include: for each set: converting the subband waveform from serial to parallel, wherein the resulting parallel components of the subband waveform are at least partially overlapped; converting multiple at least partially overlapping parallel components of the subband waveform into the frequency domain; applying a window function to the frequency domain parallel overlapping components of the subband waveform; removing overlapping blocks from the windowed frequency domain parallel overlapping components of the subband waveform, and converting the resulting parallel components into a serial subband waveform; interpolating the serial subband waveform; and modulating the interpolated serial subband waveform to a third frequency; and combining the resulting modulated interpolated serial subband waveforms of each set into a single waveform.

[0113] The third frequency may be f m =f SCS L / M[(M-1) / 2-m], where: f SCS is the subcarrier spacing frequency of a single waveform; L is the number of subcarriers, M is the number of sets, and m is the number of the set and is an integer value varying between 0 and M-1.

[0114] Interpolation may include upsampling and filtering the modulated sub-band waveform.

[0115] Upsampling may include inserting a certain number of zeros between samples of the modulated sub-band waveform.

[0116] The method may include, prior to mapping, performing a discrete Fourier transform on the time domain symbols to generate frequency domain symbols to be mapped onto a plurality of subcarriers.

[0117] According to one aspect, a method is provided, the method comprising: separating a single waveform into two or more sub-band waveforms; for each sub-band waveform: converting the sub-band waveform into multiple time domain symbol sequences; removing a cyclic prefix from each of the multiple time domain symbol sequences; converting each of the resulting multiple symbols from the time domain to the frequency domain; performing a symbol-by-symbol rotation on the frequency domain symbols based on a complex coefficient value; and mapping the rotated frequency domain symbols derived from each sub-band waveform into a single set including multiple rotated frequency domain symbols on multiple subcarriers.

[0118] Converting the plurality of symbols from the time domain to the frequency domain may include applying a fast Fourier transform to each symbol of the plurality of symbols.

[0119] The complex coefficient value can be φ m，b =exp(+2jπθ m，b ),in:

[0120]

[0121] L is the number of subcarriers,

[0122] M is the number of sets,

[0123] b is the index of the symbol,

[0124] m is the index of the collection and is an integer value ranging from 0 to M-1, and

[0125] N CP,k is the length of the cyclic prefix.

[0126] The method may include, for each sub-band waveform: demodulating the sub-band waveform from the second frequency; extracting the demodulated sub-band waveform; demodulating the extracted demodulated sub-band waveform from the first frequency; and converting the resulting sub-band waveform into a plurality of time-domain symbol sequences.

[0127] The first frequency may be c m / M, where: M is the number of sets; and c m is an implementation specific parameter used to enhance the portion of the spectrum of the sub-band waveform.

[0128] The second frequency may be f m =f SCS L / M[(M-1) / 2-m]-c m , where: f SCS is the subcarrier spacing frequency of a single waveform; L is the number of subcarriers, M is the number of sets, m is the set number and is an integer value varying between 0 and M-1, and c m is an implementation specific parameter used to enhance the portion of the spectrum of the sub-band waveform.

[0129] Decimation may include filtering and downsampling the demodulated sub-band waveforms.

[0130] Downsampling may include removing a certain number of samples from the samples of the demodulated sub-band waveform.

[0131] Separating a single waveform into two or more sub-band waveforms may include: dividing the single waveform into multiple partially overlapping blocks including one or more time domain symbols; converting each partially overlapping time domain symbol block to the frequency domain; dividing the resulting frequency domain symbols into multiple partially overlapping frequency domain symbol sets; and for each set: applying a window function to the frequency domain symbol set; converting the windowed frequency domain symbol set to the time domain; removing the overlapping portions from each partially overlapping time domain symbol set, and combining the resulting symbols into sub-band waveforms.

[0132] For each sub-band waveform, the size Po of the overlapped block may be smaller than the size P of the block.

[0133] Separating a single waveform into two or more sub-band waveforms may include: for each sub-band waveform: demodulating the sub-band waveform from a third frequency; extracting the demodulated sub-band waveform; separating the extracted demodulated sub-band waveform into a plurality of partially overlapping symbol blocks, wherein each symbol block at least partially overlaps with at least one other symbol block; and for each block: converting the partially overlapping symbol block to the frequency domain; applying a window function to the frequency domain partially overlapping symbol block; converting the resulting frequency domain partially overlapping symbol block to the time domain; and removing overlapping symbols from each time domain partially overlapping symbol block, and combining the resulting symbols into a sub-band waveform.

[0134] The third frequency may be f m =f SCS L / M[(M-1) / 2-m], where: f SCS is the subcarrier spacing frequency of a single waveform; L is the number of subcarriers, M is the number of sets, and m is the number of the set and is an integer value varying between 0 and M-1.

[0135] Decimation may include filtering and downsampling the modulated sub-band waveform.

[0136] Downsampling may include removing a certain number of samples from the samples of the modulated sub-band waveform.

[0137] The method may include performing an inverse discrete Fourier transform on the mapped symbols to generate a plurality of time domain symbols on a plurality of subcarriers.

[0138] According to one aspect, a computer-readable medium including instructions is provided, which, when executed by an apparatus, causes the apparatus to at least perform: mapping frequency domain symbols on a plurality of subcarriers into at least two sets, each set including symbols of at least one subcarrier among the plurality of subcarriers; for each set: performing symbol-by-symbol rotation based on a complex coefficient value, and converting the rotated symbol from the frequency domain to the time domain; or converting the symbol from the frequency domain to the time domain, and performing symbol-by-symbol rotation on the time domain symbol based on the complex coefficient value; inserting a cyclic prefix into each time domain symbol; concatenating the time domain symbols generated by the cyclic prefix insertion to generate a subband waveform; and performing subband filtering, interpolation, and combining based on the subband waveform of each set in the set to generate a single waveform.

[0139] The two or more sets may include one or more active sets and one or more inactive sets, wherein the one or more active sets may contain mapped frequency domain symbols, and wherein the one or more inactive sets may not contain mapped frequency domain symbols.

[0140] Converting the rotated symbols from the frequency domain to the time domain may include applying an inverse fast Fourier transform to each of the rotated symbols.

[0141] The complex coefficient value can be φ m,b =exp(-2jπθ m,b ),in:

[0142]

[0143] L is the number of subcarriers,

[0144] M is the number of sets,

[0145] b is the index of the symbol,

[0146] m is the index of the collection and is an integer value ranging from 0 to M-1, and

[0147] N CP,k is the length of the cyclic prefix.

[0148] Performing subband filtering, interpolation, and combining based on subband waveforms to generate a single waveform may include: for each set: modulating the subband waveform to a first frequency; interpolating the modulated subband waveform; and modulating the interpolated modulated subband waveform to a second frequency; and combining the resulting interpolated and modulated subband waveforms of each set into a single waveform.

[0149] The first frequency may be c m / M, where: M is the number of sets; and c m is an implementation specific parameter used to control the spectrum of the subband waveform.

[0150] The second frequency may be f m =f SCS L / M[(M-1) / 2-m]-c m , where: f SCS is the subcarrier spacing frequency of the generated waveform; L is the number of subcarriers, M is the number of sets, m is the set number and is an integer value varying between 0 and M-1, and c m is an implementation specific parameter used to control the spectrum of the subband waveform.

[0151] Interpolation may include upsampling and filtering the modulated sub-band waveform.

[0152] Upsampling may include inserting a certain number of zeros between samples of the modulated sub-band waveform.

[0153] Performing subband filtering, interpolation and combination based on the subband waveform to generate a waveform may include: for each set: dividing the symbols of the subband waveform into multiple overlapping blocks; converting the multiple overlapping blocks to the frequency domain; applying a window function to each overlapping block in the overlapping blocks in the frequency domain to generate multiple windowed blocks; converting the multiple windowed blocks from the frequency domain to the time domain; and discarding a subset of each windowed block in the multiple windowed blocks in the time domain; and combining the resulting time domain windowed blocks of each set in the set into a single waveform.

[0154] For each set, the size Po of the overlapping block may be smaller than the size P of the block.

[0155] The number of discarded samples may be Qo=PoM, where M is the number of sets.

[0156] Performing subband filtering, interpolation, and combining based on subband waveforms to generate waveforms may include: for each set: converting the subband waveform from serial to parallel, wherein the resulting parallel components of the subband waveform are at least partially overlapped; converting multiple at least partially overlapping parallel components of the subband waveform into the frequency domain; applying a window function to the frequency domain parallel overlapping components of the subband waveform; removing overlapping blocks from the windowed frequency domain parallel overlapping components of the subband waveform, and converting the resulting parallel components into a serial subband waveform; interpolating the serial subband waveform; and modulating the interpolated serial subband waveform to a third frequency; and combining the resulting modulated interpolated serial subband waveforms of each set into a single waveform.

[0157] The third frequency may be f m =f SCS L / M[(M-1) / 2-m], where: f SCS is the subcarrier spacing frequency of a single waveform; L is the number of subcarriers, M is the number of sets, and m is the number of the set and is an integer value varying between 0 and M-1.

[0158] Interpolation may include upsampling and filtering the modulated sub-band waveform.

[0159] Upsampling may include inserting a certain number of zeros between samples of the modulated sub-band waveform.

[0160] When the instruction is executed by the device, it may cause the device to further execute: before mapping, performing discrete Fourier transform on the time domain symbols to generate frequency domain symbols to be mapped onto multiple subcarriers.

[0161] According to one aspect, a computer-readable medium comprising instructions is provided, which, when executed by an apparatus, causes the apparatus to at least perform: separating a single waveform into two or more sub-band waveforms; for each sub-band waveform: converting the sub-band waveform into a plurality of time domain symbol sequences; removing a cyclic prefix from each of the plurality of time domain symbol sequences; converting each of the resulting plurality of symbols from the time domain to the frequency domain; performing symbol-by-symbol rotation on the frequency domain symbols based on a complex coefficient value; and mapping the rotated frequency domain symbols derived from each sub-band waveform into a single set comprising a plurality of rotated frequency domain symbols on a plurality of subcarriers.

[0162] Converting the plurality of symbols from the time domain to the frequency domain may include applying a fast Fourier transform to each symbol of the plurality of symbols.

[0163] The complex coefficient value can be φ m，b =exp(+2jπθ m，b ),in:

[0164]

[0165] L is the number of subcarriers,

[0166] M is the number of sets,

[0167] b is the index of the symbol,

[0168] m is the index of the collection and is an integer value ranging from 0 to M-1, and

[0169] N CP,k is the length of the cyclic prefix.

[0170] When executed by the device, the instructions may cause the device to further perform: for each sub-band waveform: demodulating the sub-band waveform from the second frequency; extracting the demodulated sub-band waveform; demodulating the extracted demodulated sub-band waveform from the first frequency; and converting the obtained sub-band waveform into multiple time domain symbol sequences.

[0171] The first frequency may be c m / M, where: M is the number of sets; and cm is an implementation specific parameter used to enhance the portion of the spectrum of the sub-band waveform.

[0172] The second frequency may be f m =f SCS L / M[(M-1) / 2-m]-c m , where: f SCS is the subcarrier spacing frequency of a single waveform; L is the number of subcarriers, M is the number of sets, m is the set number and is an integer value varying between 0 and M-1, and c m is an implementation specific parameter used to enhance the portion of the spectrum of the sub-band waveform.

[0173] Decimation may include filtering and downsampling the demodulated sub-band waveforms.

[0174] Downsampling may include removing a certain number of samples from the samples of the demodulated sub-band waveform.

[0175] Separating a single waveform into two or more sub-band waveforms may include: dividing the single waveform into multiple partially overlapping blocks including one or more time domain symbols; converting each partially overlapping time domain symbol block to the frequency domain; dividing the resulting frequency domain symbols into multiple partially overlapping frequency domain symbol sets; and for each set: applying a window function to the frequency domain symbol set; converting the windowed frequency domain symbol set to the time domain; removing the overlapping portions from each partially overlapping time domain symbol set, and combining the resulting symbols into sub-band waveforms.

[0176] For each sub-band waveform, the size Po of the overlapped block may be smaller than the size P of the block.

[0177] Separating a single waveform into two or more sub-band waveforms may include: for each sub-band waveform: demodulating the sub-band waveform from a third frequency; extracting the demodulated sub-band waveform; separating the extracted demodulated sub-band waveform into a plurality of partially overlapping symbol blocks, wherein each symbol block at least partially overlaps with at least one other symbol block; and for each block: converting the partially overlapping symbol block to the frequency domain; applying a window function to the frequency domain partially overlapping symbol block; converting the resulting frequency domain partially overlapping symbol block to the time domain; and removing overlapping symbols from each time domain partially overlapping symbol block, and combining the resulting symbols into a sub-band waveform.

[0178] The third frequency may be f m =f SCS L / M[(M-1) / 2-m], where: f SCS is the subcarrier spacing frequency of a single waveform; L is the number of subcarriers, M is the number of sets, and m is the number of the set and is an integer value varying between 0 and M-1.

[0179] Decimation may include filtering and downsampling the modulated sub-band waveform.

[0180] Downsampling may include removing a certain number of samples from the samples of the modulated sub-band waveform.

[0181] When the instruction is executed by the device, it can cause the device to further execute: performing an inverse discrete Fourier transform on the mapped symbols to generate multiple time domain symbols on multiple subcarriers.

[0182] According to one aspect, a non-transitory computer-readable medium including program instructions is provided, which, when executed by an apparatus, causes the apparatus to at least perform a method according to any one of the preceding aspects.

[0183] In the above, many different embodiments have been described. It should be understood that other embodiments can be provided by combining any two or more of the above embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0184] Embodiments will now be described, by way of example only, with reference to the accompanying drawings, in which:

[0185] Figure 1 shows a representation of a network system according to some example embodiments;

[0186] Figure 2 shows a representation of a control device according to some example embodiments;

[0187] Figure 3 shows representations of apparatus according to some example embodiments;

[0188] Figure 4 A block diagram showing examples of conventional OFDM and DFT-s-OFDM waveform generation;

[0189] Figure 5 Methods according to some examples are shown;

[0190] Figure 6 shows a block diagram of OFDM or DFT-s-OFDM waveform generation according to some examples;

[0191] Figure 7 A block diagram of OFDM or DFT-s-OFDM symbol regeneration according to some examples is shown;

[0192] Figure 8 Shows the use of Figure 6 and Figure 7 Example power spectral density of a DFT-s-OFDM waveform achieved by the decomposition process described;

[0193] Fig. 9A block diagram showing an example of OFDM waveform generation according to some examples using time domain interpolation and combining;

[0194] Fig.10 (a)- Fig.10 (d) shows examples of spectrum positioning with and without modulation before and after filtering;

[0195] Fig.11 Shows the use of Fig. 9 Example PSD of an OFDM waveform achieved by the decomposition process described;

[0196] Fig.12 A block diagram showing an example of OFDM waveform generation according to some examples using frequency domain interpolation and combining;

[0197] Fig.13 Shown using the above Fig.12 Example PSD of an OFDM waveform achieved by the decomposition process described;

[0198] Fig.14 shows a block diagram of an example of OFDM waveform generation according to some examples using time domain interpolation and combining with additional frequency domain filtering;

[0199] Fig.15 Shown using the above Fig.14 Example PSD of an OFDM waveform achieved by the decomposition process described. DETAILED DESCRIPTION

[0200] A non-exhaustive list of some abbreviations used in this disclosure is provided below for reference: ACLR: Adjacent Channel Leakage Rate

[0201] BS: Base Station

[0202] CA: Carrier Aggregation

[0203] CC: Composite Carrier

[0204] CP: Cyclic Prefix

[0205] DFE: Digital Front End

[0206] DFT: Discrete Fourier Transform

[0207] DFT-s-OFDM: DFT spread spectrum OFDM

[0208] DL: Downlink

[0209] EVM: Error Vector Magnitude

[0210] FDE: Frequency Domain Equalizer

[0211] FDSS: Frequency Domain Spectral Shaping

[0212] FFT: Fast Fourier Transform

[0213] FR: Frequency range

[0214] IBE: In-Band Emission

[0215] IDFT: Inverse Discrete Fourier Transform

[0216] IFFT: Inverse Fast Fourier Transform

[0217] MCS: Modulation Coding Scheme

[0218] MPR: Maximum Power Reduction

[0219] MSK: Minimum Shift Keying

[0220] NR: New Radio

[0221] OBO: Output Back Off

[0222] OBW: Occupied Bandwidth

[0223] OFDM: Orthogonal Frequency Division Multiplexing

[0224] OLA: Overlap and Add

[0225] OOB: Out of Band

[0226] PA: Power Amplifier

[0227] PAPR: Peak to Average Power Ratio

[0228] PRB: Physical Resource Block

[0229] PSD: Power Spectral Density

[0230] PSK: Phase Shift Keying

[0231] QAM: Quadrature Amplitude Modulation

[0232] QPSK: Quadrature Phase Shift Keying

[0233] RF: Radio Frequency

[0234] RX: Receiver

[0235] SCS: Subcarrier Spacing

[0236] TX: Transmitter

[0237] UE: User Equipment

[0238] UL: Uplink

[0239] WOLA: Weighted Overlap and Add

[0240] In the following, certain embodiments are explained with reference to a mobile communication device capable of communicating via a wireless cellular system and a mobile communication system serving such a mobile communication device. Figure 1 , Figure 2 and Figure 3 Certain general principles of wireless communication systems, their access systems and mobile communication devices are briefly explained to help understand the technology behind the described examples.

[0241] Figure 1 A schematic diagram of a 5G system (5GS) is shown. The 5GS may consist of a terminal or user equipment (UE), a 5G radio access network (5GRAN) or a next generation radio access network (NG-RAN), a 5G core network (5GC), one or more application functions (AFs), and one or more data networks (DNs).

[0242] The 5G-RAN may include one or more gNodeBs (GNBs) connected to one or more gNodeB (GNB) centralized unit functions, or one or more gNodeB (GNB) distributed unit functions.

[0243] 5GC may include the following entities: network slice selection function (NSSF); network exposure function; network repository function (NRF); policy control function (PCF); unified data management (UDM); application function (AF); authentication server function (AUSF); access and mobility management function (AMF); and session management function (SMF). Figure 1 Also shown are various interfaces (N1, N2, etc.) that can be implemented between the various elements of the system. Similar functionality can be provided in 6G systems.

[0244] Figure 2 The diagram shows the Figure 1An example of a control device 200 for the functions of the illustrated 5GRAN or 5GC. The control device may include at least one random access memory (RAM) 211a, at least one read-only memory (ROM) 211b, at least one processor 212, 213, and an input / output interface 214. At least one processor 212, 213 may be coupled to the RAM 211a and the ROM 211b. At least one processor 212, 213 may be configured to execute appropriate software code 215. The software code 215 may, for example, allow one or more steps to be executed to perform one or more of the present aspects. The software code 215 may be stored in the ROM 211b. The control device 200 may be interconnected with another control device 200 that controls another function of the 5GRAN or 5GC. In some embodiments, each function of the 5GRAN or 5GC includes a control device 200. In an alternative embodiment, two or more functions of the 5GRAN or 5GC may share a control device.

[0245] Figure 3 An example of a terminal 300 is shown, such as Figure 1 The terminal 300 can be provided by any device capable of sending and receiving radio signals. Non-limiting examples include user equipment, mobile stations (MS) or mobile devices (such as mobile phones or so-called 'smart phones'), computers equipped with wireless interface cards or other wireless interface facilities (e.g., USB dongles), personal data assistants (PDAs) or tablets equipped with wireless communication functions, machine type communication (MTC) devices, Internet of Things (IoT) type communication devices, or any combination thereof. The terminal 300 can provide data communications, such as for bearer communications. The communication can be one or more of voice, electronic mail (email), text messages, multimedia, data, machine data, etc.

[0246] The terminal 300 may receive signals over the air or radio interface 307 via suitable means for receiving, and may transmit signals via suitable means for transmitting radio signals. Figure 3 In the mobile device, the transceiver device is schematically represented by a block 306. The transceiver device 306 may be provided, for example, by a radio component and an associated antenna arrangement. The antenna arrangement may be arranged internally or externally to the mobile device.

[0247] The terminal 300 may be equipped with at least one processor 301, at least one memory ROM 302a, at least one RAM 302b and other possible components 303 for software and hardware-assisted execution of the tasks it is designed to perform, including controlling access and communication to access systems and other communication devices. At least one processor 301 is coupled to RAM 302b and ROM 302a. At least one processor 301 may be configured to execute appropriate software code 308. Software code 308 may, for example, allow execution of one or more aspects of the present aspect. Software code 308 may be stored in ROM 302a.

[0248] The processor, storage device and other related control devices may be arranged on an appropriate circuit board and / or in a chipset. This feature is indicated by reference numeral 304. The device may optionally have a user interface, such as a keypad 305, a touch-sensitive screen or touchpad, a combination thereof, etc. Depending on the type of device, one or more of a display, a speaker and a microphone may be optionally provided.

[0249] According to some existing standards, the maximum channel bandwidth (CBW) supported by the fifth generation new radio (5G-NR) in frequency range 1 (FR1) is 100 MHz. Figure 4 A block diagram of an example of conventional OFDM and DFT-s-OFDM waveform generation is shown. The block diagram includes the following steps: DFT 400, subcarrier mapping 402, inverse FFT 404, cyclic prefix (CP) insertion 406, and parallel to serial conversion 408.

[0250] exist Figure 4 In the example shown, b=0, 1, ..., B-1 is the OFDM / DFT-s-OFDM symbol index, where B is the number of OFDM or DFT-s-OFDM symbols.

[0251] In the case of DFT-s-OFDM, at 400, for the b-th multi-carrier symbol, a DFT (or FFT) of size L is used to transform L time-domain BPSK, QPSK or QAM symbols x l，b (where l=0, 1, ..., L-1) is converted to the frequency domain.

[0252] At 402, the output bins are mapped to the input bins of a size N IFFT 404 (so that the remaining NL bins are zero), and the zero-filled frequency domain bins are converted back to the time domain.

[0253] At 406, the length N CP，b The cyclic prefix (CP) is inserted into the output of the IFFT. At 408, the resulting DFT-s-OFDM symbols are converted from parallel to serial, for example, by concatenation.

[0254] In the case of an OFDM waveform, the DFT block 400 can be omitted. For example, the input is L frequency-domain BPSK, QPSK, or QAM symbols X l，b (where l = 0, 1,..., L-1). The subsequent stages can be processed as in the above DFT-s-OFDM waveform generation.

[0255] The required IFFT transform size applied at 404 can be determined as the ratio of the output sampling rate and the subcarrier spacing (SCS), i.e., N = F S / f SCS . For example, to support a 200 MHz (aggregated) carrier (F SCS = 245.76 Msps sampling rate) with f S = 30 kHz SCS, an IFFT of N = 8192 is required.

[0256] The DFT size can be limited to L = L1 × L2 × L3, where L1 = 2 p , L2 = 3 q , and L3 = 5 r . Here, p, q, and r are non-negative integers. When using the prime factor algorithm to implement the DFT, the actual transform size to be implemented is L1, L2, and L3. Since L < N, the largest power-of-2 transform size L1 is always less than N, and thus, the DFT can be implemented using an existing power-of-2 transform size (e.g., less than or equal to 4096).

[0257] In some future developments such as the sixth generation (6G), a wider CBW can be defined. A wider CBW can increase throughput. To implement a wider CBW, the required IFFT size can also increase. For example, a CBW of up to 400 MHz, an IFFT size of 16384 for 30 kHz SCS, and an IFFT size of 8192 for 60 kHz SCS may be required. Extending beyond 400 MHz (e.g., to 500 MHz) may not be easily achieved by scaling NR digital technology because when using a single IFFT (e.g., 16384 or 32768), the IFFT utilization or BW utilization (or both) may be compromised.

[0258] In other words, increasing the CBW can mean that the required IFFT / FFT, and / or DFT / IDFT size increases above the existing maximum transform size required to support 5G-NR carriers, e.g., greater than 4096.

[0259] Therefore, alternative methods for implementing FFT / IFFT and / or DFT / IDFT longer than the existing size (e.g., 4096) using the existing IFFT as a building block may be beneficial. These alternative methods for implementing long transform sizes may also be beneficial for generating future (e.g., sixth generation) carrier types, as the transmission band may be increased beyond the 100 MHz bandwidth currently supported by the 5G-NR maximum transform size and standardized subcarrier spacing.

[0260] Some examples of the present disclosure provide example implementations for generating wide (e.g., CBW>100MHz) OFDM and DFT-s-OFDM waveforms. Some examples may use existing transform sizes and perform additional processing. Some examples may provide transparent waveform processing relative to conventional OFDM / DFT-s-OFDM methods. The spectral inclusion of waveforms generated using the proposed methods may be enhanced compared to some conventional schemes.

[0261] Some examples may help enable implementation of efficient large IFFT sizes. Some examples may enable increased maximum CBW without needing to follow the power-of-two scaling rule for a single IFFT. Some examples may enable more flexible channel bandwidth configurations, such as 500 MHz CBW.

[0262] Some examples may help enable improved energy efficiency of the transmitter and / or receiver in situations where only a portion of the carrier bandwidth needs to be processed. For example, if a UE supporting 400 MHz CBW is expected to operate with a transmit or receive bandwidth of 100 MHz, it may wish to reduce the FFT / IFFT bandwidth (e.g., from 16384 to 4096). This can be achieved by decomposing the OFDM and DFT-s-OFDM waveform generation. In some examples, different combined transform block sizes may be used to achieve the same overall bandwidth. For example, the FFT / IFFT may be implemented using 2×4096 or 4×2048 block sizes to support the same transmission bandwidth. In some cases, different implementations may have different energy saving capabilities. The choice of transform block combination may be implementation specific.

[0263] refer to Figure 5 , Figure 5 Methods according to some examples are shown.

[0264] At 500, the method includes mapping frequency-domain symbols on a plurality of subcarriers into at least two sets, each set including symbols for at least one subcarrier of the plurality of subcarriers.

[0265] At 502, for each set, the method includes:

[0266] Performing symbol-by-symbol rotation based on the complex coefficient values ​​and converting the rotated symbols from the frequency domain to the time domain; or converting the symbols from the frequency domain to the time domain and performing symbol-by-symbol rotation on the time domain symbols based on the complex coefficient values; and

[0267] A cyclic prefix is ​​inserted into each time domain symbol; and the time domain symbols generated by the cyclic prefix insertion are concatenated to generate a sub-band waveform.

[0268] At 504, the method includes performing subband filtering, interpolation, and combining based on the subband waveforms of each of the sets to generate a single waveform.

[0269] At 506, a method includes separating a single waveform into two or more sub-band waveforms.

[0270] At 508, the method includes, for each sub-band waveform:

[0271] Converting a subband waveform into a plurality of time-domain symbol sequences;

[0272] removing a cyclic prefix from each of a plurality of time-domain symbol sequences;

[0273] converting each symbol of the resulting plurality of symbols from the time domain to the frequency domain; and

[0274] A symbol-by-symbol rotation is performed on the frequency domain symbols based on the complex coefficient values.

[0275] At 510, the method includes mapping rotated frequency-domain symbols derived from each sub-band waveform into a single set comprising a plurality of rotated frequency-domain symbols over a plurality of sub-carriers.

[0276] Some examples provide implementations of efficient decomposition implementations of large transform sizes, for example, by using multiple existing transform sizes. Different implementations may be applied to different scenarios (eg, for UE side or BS side).

[0277] Some examples may enable decomposed OFDM and DFT-s-OFDM waveform generation. Some examples may be used to generate wide carriers in 5G Advanced or 6G developments, or indeed for any other future development. Some examples may provide particular benefits for transmissions where the number of subcarriers is greater than the current maximum size, such as the current maximum size supported by 5G-NR, e.g., 3300 or 4096. In addition, while some examples are described for scenarios where the number of subcarriers is greater than the number supported by 4096 FFT (the assumed FFT size in NR), some examples may also be applied to other scenarios, e.g., increasing the number of subcarriers beyond the number supported by 4096 FFT in possible future scenarios designed for 8192 FFTs (per component carrier).

[0278] refer to Figure 6 , Figure 6 A block diagram of OFDM or DFT-s-OFDM waveform generation according to some examples is shown.

[0279] At 600, a DFT of size L may be performed on the symbols on the L active subcarriers. In some examples, L>3300. For OFDM waveforms, this step may be omitted.

[0280] At 602, subcarrier mapping can be performed. Frequency domain intervals of symbols on L active subcarriers can be mapped into M≥2 (two or more) sets.

[0281] At 604, symbol rotation may be performed on each interval of the M sets. Each interval of the set may be multiplied by a complex coefficient value. The resulting rotated symbols may then be mapped into an input interval of the IFFT.

[0282] At 606, an IFFT may be performed separately for each set. Thus, M IFFTs may be performed. The size of the IFFT may be N / M.

[0283] In some examples, step 604 may be performed before step 606, such as Figure 6 However, in other examples, step 606 may be performed before step 604. That is, in some examples, IFFT may be performed based on the output of step 602, and then the symbols obtained by the IFFT may be rotated, and then a cyclic prefix may be added to the rotated time domain symbols at 608.

[0284] At 608, a cyclic prefix (CP) may be inserted into each symbol obtained by the IFFT. The size of the CP may be N CP，b / M.

[0285] A parallel-to-serial conversion can be performed at 610. For example, the symbols can be concatenated to form a sub-band waveform.

[0286] At 612, interpolation, modulation, and combination of the sub-band waveforms from each set may be performed. The interpolation factor may be, for example, an integer greater than 1, such as 2. The sub-band waveforms may be interpolated using interpolation filtering. As a result of step 612, the resulting waveform may be continuous in frequency.

[0287] In some examples, the same method as described above with respect to Figure 6 The reverse process described above is used to obtain the symbols on the L active subcarriers. Figure 7 An example thereof is described.

[0288] The waveform may be demodulated and decimated by the same factor used in modulation at 700. For example, the waveform may be demodulated (eg, frequency shifted) and decimated by a factor of 1 / 2 using decimation filtering to separate the sub-band waveforms.

[0289] At 702, separated sub-band waveforms can be converted from serial to parallel.

[0290] At 704, CP removal may be performed. For example, a CP of length N may be removed from each symbol. CP，b / M's CP.

[0291] At 706, for each set, a separate Fast Fourier Transform (FFT) may be performed. Thus, in some examples, M FFTs may be performed. Each FFT may be of size N / M.

[0292] At 708, a sign direction (de)rotation may be performed on each bin of the M sets. For example, each bin may be multiplied by a complex coefficient value.

[0293] At 710, the rotated frequency domain bins may be mapped into input bins of a size-L IDFT.

[0294] At 712, an inverse discrete Fourier transform (IDFT) may be performed on the rotated frequency domain bins to obtain symbols on the L active subcarriers. In examples where the waveform is an OFDM waveform rather than a DFT-s-OFDM waveform, step 712 may be omitted.

[0295] Figure 8 Shown using the above Figure 6 and Figure 7 The power spectral density (PSD) of the DFT-s-OFDM waveform achieved by the decomposition process described in Figure 8 In the example, L = L1 × L2 × L3 = 6480, where L1 = 2 4 , L2=3 4 , and L3=5 1 , N = 2 x 4096. The interpolation and combining (eg, at step 612) in this example are implemented using time domain processing.

[0296] Figure 8 Results for two designs using the proposed method are shown. For the first design 800, an interpolation filter of length P=27 with only 7 non-trivial multipliers is used. For the second design 802, a filter of length P=163 with 41 non-trivial multipliers is used. For comparison, the results for conventional DFT-s-OFDM 804 are also shown.

[0297] From this figure, it can be seen that the PSDs of all methods are fairly consistent within the channel bandwidth 806. However, at the edge of the channel bandwidth, such as in the region 808 on either side of the channel bandwidth 806, it can be seen that the first design with decomposition processing has substantially lower spectral leakage than the conventional method. This indicates that the PSD decreases more rapidly from the edge of the channel bandwidth to a value below -50 dBm per 100 kHz measurement bandwidth (MBW), while the PSD of the conventional method decreases more slowly to reach -50 dBm per 100 kHz MBW.

[0298] Furthermore, it can be seen that by increasing the filter order, as in the second design, the spectral localization can be further improved. This is shown by the rapid drop in PSD from the edge of the channel bandwidth to values ​​of -60 to -80 dBm per 100 kHz MBW.

[0299] In some examples, interpolation and combining can be performed in the time domain. In some examples, interpolation and combining can be performed in the frequency domain. In some examples, interpolation and combining can be performed in the time domain, and additional frequency domain filtering can be applied before interpolation.

[0300] In the following, examples are described in the context of OFDM waveform generation. In some examples, corresponding DFT-s-OFDM waveform generation can be achieved by introducing DFT spreading / precoding before OFDM waveform generation, e.g., as previously described Figure 4 As shown in step 400 in the embodiment. Some examples may be implemented at or by a UE and / or a base station.

[0301] Time Domain Interpolation and Combination

[0302] refer to Fig. 9 , Fig. 9 A block diagram showing an example of OFDM waveform generation according to some examples using time domain interpolation and combining is shown.

[0303] Subcarrier mapping is performed at 900. Frequency domain intervals of symbols on the L active subcarriers may be mapped into two or more sets.

[0304] For example, Fig. 9 As shown in l，b (where l=0, 1, ..., L-1) may identify a symbol (eg, a BPSK / QPSK / QAM symbol) on the L active subcarriers of the b-th multicarrier symbol. Symbol X l，b can be divided into M sets. For example, the first set may contain symbols X l，b (where l = 0, 1, ..., L / M-1), the second set may contain symbols X l，b(where l=L / M, L / M+1, ..., 2L / M-1), etc.

[0305] At 902, symbol rotation can be performed on each interval of the M sets.

[0306] For example, the symbols in the mth set (where m=0, 1, ..., M-1) may be multiplied by a complex coefficient value. For example, the complex coefficient value may be:

[0307] φ m,b =exp(-2jπθ m,b )

[0308] In some examples

[0309]

[0310] At 904, each rotated symbol set may be input into an inverse fast Fourier transform (IFFT), and an IFFT may be performed on each symbol set. The size of the IFFT may be N / M. A total of M IFFTs of size N / M may be performed.

[0311] At 906, for each set, a cyclic prefix is ​​added to the output of the IFFT. The CP may have a length of N CP，b / M.

[0312] At 908, the resulting symbols in each set are converted from parallel to serial, such as by concatenation. This may result in a subband waveform for each set.

[0313] At 910, for each set, a subband waveform may be modulated to a first frequency. The first frequency may be c m / M. Parameter c m This will be discussed in further detail below.

[0314] At 912, interpolation may be performed on the modulated sub-band waveform. The interpolation may be performed by a factor of I ≥ M. For example, the resulting sub-waveform may be upsampled by I by inserting I-1 zeros between samples and then filtering the resulting spectral image from the upsampled waveform.

[0315] In some examples, at step 912, when I can be decomposed into I=I1I2, interpolation can be implemented in two stages. The first stage can include upsampling the result of step 610 by a factor of I1 and filtering it through a first subfilter. The second stage can include upsampling the result of the first stage by a factor of I2 and filtering it through a second subfilter. In general, in some examples, when I can be decomposed into S stages, that is, I=I1I2...I SWhen , interpolation can be implemented in S steps. In some examples, I = M. However, in other examples, I ≠ M, and when M is not a power of 2, I can be selected as, for example

[0316] At 914, the interpolated waveform may be modulated to a second frequency. The second frequency may be f m =f SCS L / M[(M-1) / 2-m]-c m .

[0317] At 916, each set of interpolated and modulated waveforms may be combined into a single OFDM waveform.

[0318] In some examples, increasing the filter order may not improve spectral localization when interpolating by a factor of 2 using digitally efficient interpolators. This may be due to the fact that the normalized passband and stopband filter edges can be related to ω. s =1-ω p correlation, and therefore, the normalized stopband filter edge can be greater than 0.5.

[0319] An example of this is Fig.10 (a) and Fig.10 (b) is shown, Fig.10 (a) and Fig.10 (b) shows the p To -ω p The sub-band waveform between Fig.10 In the example (a), parameter c m =0, and the minimum normalized stopband filter edge is greater than 0.5.

[0320] In some examples, c m The value of can be determined iteratively, for example by numerical optimization. In other examples, c m The value of can be defined based on the PSD of the waveform and the spectral characteristics of the filter. The PSD of the waveform can be determined by L and N, and the filter amplitude response can be determined by the filter order and the passband (or stopband) edge. Both of these responses can be defined analytically and can be derived to give c m In some examples, by adjusting c m The value of can be used to control the spectrum of the waveform depending on the implementation - for example, parts of the spectrum can be boosted or suppressed as needed based on attenuation requirements. In some examples, the normalized frequency (c0 / (Fs / 2)) can have a value between 0 and 0.5, where Fs is the interpolated sampling rate (e.g., the sampling rate at the output of the filter).

[0321] However, the rightmost and leftmost subband waveforms can be frequency shifted to the right and left edges of the filter passband region, respectively, by performing modulation at step 910. As a result, a narrow transition band can be achieved at the expense of additional modulation.

[0322] exist Fig.10 (c) and Fig.10 In the example (d), parameter c m ≠0, and the subband is offset to the right edge of the filter passband. Fig.10 (c) and Fig.10 As shown in (d), the center frequency of the obtained sub-band is f c , instead of Fig.10 (a) and Fig.10 (b) shows a center frequency of 0. As a result, a reduction in spectral leakage of the filtered sub-band waveform is achieved. In some examples, the frequency shift of the sub-band waveform may be compensated in step 914.

[0323] exist Fig.10 , an example filter response is shown as 1000. Fig.10 (a) and Fig.10 (c) shows an example of the spectrum after upsampling and before filtering, and Fig.10 (b) and Fig.10 (d) shows an example of the spectrum after applying the filter.

[0324] Generally speaking, interpolation can be implemented in two steps:

[0325] 1) Upsampling (inserting zeros between the original samples, which can generate a spectral image of the original spectrum. Fig.10 (a) and Fig.10 (c) shows an example thereof, where half of the spectrum image is located on the left side of the sub-band waveform 1004 at 1002a, and the other half is located on the right side of the sub-band waveform 1004 at 1002b); and

[0326] 2) Filter the result to remove the redundant spectrum image, where the waveform and PSD obtained are as follows: Fig.10 (b) and Fig.10 As shown in (d).

[0327] In some implementations, these steps may be implemented simultaneously, rather than separately. Although the "ideal" spectrum produced by filtering may have a box-like shape, in practice, this may not be achieved. Instead, the measured PSD may follow a pattern similar to that shown by line 1008.

[0328] In some examples, the normalized minimum stopband edge frequency of the filter may be limited to + / -0.5. Thus, when applying the filter to try and remove the extra spectral image, in [-0.5, ω p ] to [ω p , 0.5] may have some relatively high spectral sidelobes, such as Fig.10 As shown in (b).

[0329] Fig.10 (c) and Fig.10 An example is shown in (d), where the subband waveform is shifted to the right before filtering, Fig.10 (c) shows the shifted spectrum after upsampling, and Fig.10 (d) shows the shifted and filtered spectrum.

[0330] like Fig.10 As shown in (d), a narrow portion of the original spectrum side lobe (as shown in 1010) exists on the right side of the sub-band waveform. On the left side of the sub-band waveform, although there may be a larger side lobe, as shown in 1012, in practice, another sub-band waveform can be aligned on top of the side lobe 1012 (after similarly shifting in the opposite direction), and thus better spectrum confinement can be achieved on the right side of the sub-band waveform, with little impact elsewhere in the spectrum.

[0331] Fig.11 An example PSD of an OFDM waveform is shown, where 1100 shows the use of the above-mentioned Fig. 9 1102 and 1104 show some illustrative spectrum emission masks for comparison. Fig. 9 The described processing can improve the spectrum positioning, as shown by the PSD dropping from the edge of the channel bandwidth to a value of -80dBm per 100kHz MBW at the edge of the plot. Frequency Domain Interpolation and Combination

[0332] refer to Fig.12 , Fig.12 A block diagram of an example of OFDM waveform generation according to some examples using frequency domain interpolation and combining is shown. Blocks 1200-1208 may be similar to blocks 900-908 described previously.

[0333] Subcarrier mapping is performed at 1200. Frequency domain intervals of symbols on the L active subcarriers may be mapped into two or more sets.

[0334] For example, Fig.12 As shown in l，b(where l=0, 1, ..., L-1) may identify a symbol (eg, a BPSK / QPSK / QAM symbol) on the L active subcarriers of the b-th multicarrier symbol. Symbol X l，b can be divided into M sets. For example, the first set may contain symbols X l，b (where l = 0, 1, ..., L / M-1), the second set may contain symbols X l，b (where l=L / M, L / M+1, ..., 2L / M-1), etc.

[0335] At 1202, symbol rotation may be performed on each interval of the M sets.

[0336] For example, the symbols in the mth set (where M=0, 1, ..., M-1) may be multiplied by a complex coefficient value. For example, the complex coefficient value may be:

[0337] φ m，b =exp(-2jπθ m，b )

[0338] In some examples

[0339]

[0340] At 1204, each rotated symbol set may be input into an inverse fast Fourier transform (IFFT), and an IFFT may be performed on each symbol set. The size of the IFFT may be N / M. A total of M IFFTs of size N / M may be performed.

[0341] At 1206, for each set, a cyclic prefix is ​​added to the output of the IFFT. The CP may have a length of N CP，b / M.

[0342] At 1208, the resulting symbols in each set are converted from parallel to serial, such as by concatenation. This may result in a subband waveform for each set.

[0343] At 1210, for each set, the subband waveform may be partitioned into overlapping blocks of length P. The overlap between blocks may be P O <P samples.

[0344] At 1212, for each set, the overlapping blocks may be converted to the frequency domain. For example, an FFT of length P may be applied to the overlapping blocks.

[0345] At 1214, the frequency domain representation of the overlapping blocks for each subband may be "windowed" or filtered by applying a frequency domain window function (eg, a bandpass filter).

[0346] At 1216, for each set, the windowed frequency domain representation may be converted back to the time domain. For example, the windowed frequency domain representation may be mapped to the input of an IFFT, and an IFFT may be performed. The size of the IFFT may be Q=MP.

[0347] At 1218, a subset of samples from the resulting time domain block may be discarded. For example, Q O =P O M samples. The resulting segments can then be combined into a single waveform, for example by concatenation.

[0348] In some examples, the block length P and overlap P O Can be chosen arbitrarily. Increasing block length and overlap can improve performance (optionally).

[0349] Fig.13 An example PSD of an OFDM waveform is shown, where 1300 shows the use of the above Fig.12 As shown in the figure, by applying the above Fig.12 The described processing can improve the spectral positioning, as shown by the PSD dropping from the edge of the channel bandwidth to a value of about -90dBm per 100kHz MBW at the edge of the plot. Fig.11 This represents a further improvement in spectral localization compared to the PSD shown.

[0350] Time domain interpolation and combination with additional frequency domain filtering

[0351] refer to Fig.14 , Fig.14 A block diagram of an example of OFDM waveform generation according to some examples using time domain interpolation and combining with additional frequency domain filtering is shown. Blocks 1400-1408 may be similar to blocks 900-908 and 1200-1208 described previously.

[0352] Subcarrier mapping is performed at 1400. Frequency domain intervals of symbols on the L active subcarriers may be mapped into two or more sets.

[0353] For example, Fig.14 As shown, X l，b (where l=0, 1, ..., L-1) may identify a symbol (eg, a BPSK / QPSK / QAM symbol) on the L active subcarriers of the b-th multicarrier symbol. Symbol X l，b can be divided into M sets. For example, the first set may contain symbols X l，b (where l = 0, 1, ..., L / M-1), the second set may contain symbols X l，b (where l=L / M, L / M+1, ..., 2L / M-1), etc.

[0354] At 1402, symbol rotation may be performed on each interval of the M sets.

[0355] For example, the symbols in the mth set (where m=0, 1, ..., M-1) may be multiplied by a complex coefficient value. For example, the complex coefficient value may be:

[0356] φ m,b =exp(-2jπθ m,b )

[0357] In some examples

[0358]

[0359] At 1404, each rotated symbol set may be input into an inverse fast Fourier transform (IFFT), and an IFFT may be performed on each symbol set. The size of the IFFT may be N / M. A total of M IFFTs of size N / M may be performed.

[0360] At 1406, for each set, a cyclic prefix is ​​added to the output of the IFFT. The CP may have a length of N CP，b / M.

[0361] At 1408, the resulting symbols in each set are converted from parallel to serial, such as by concatenation. A CP-OFDM subband waveform may be derived for each set.

[0362] At 1410, for each set, the subband waveform may be converted from serial to parallel. In some examples, there may be overlap. For example, each set may have a block length Q and an overlap QO.

[0363] At 1412, for each set, the overlapping blocks may be converted to the frequency domain. For example, this may be performed by applying an FFT of size Q to the overlapping blocks.

[0364] At 1414, the frequency domain representation of the overlapping blocks for each subband may be windowed by applying a frequency domain window function.

[0365] For each set, the windowed frequency domain blocks may be converted back to the time domain at 1416. For example, this may be performed by applying an IFFT of size Q to the windowed frequency domain blocks.

[0366] At 1418, for each set, the overlap of overlapping time-domain blocks may be removed and the resulting parallel segments may be converted to serial segments, such as by concatenation.

[0367] At 1420, for each set, the resulting subband waveform may be interpolated by a factor of I ≥ M. For example, the subband waveform may be upsampled by I by inserting I-1 zeros between samples and then filtering the resulting spectral image from the upsampled waveform.

[0368] At 1422, for each set, the interpolated waveform may be modulated to a center frequency. For example, the interpolated waveform may be modulated to a center frequency f m =f SCS L / M[(M-1) / 2-m].

[0369] At 1424, the interpolated and modulated waveforms from each set may be combined into an OFDM waveform.

[0370] Fig.15 An example PSD of an OFDM waveform is shown, where 1500 shows the use of the above-mentioned Fig.14 1502 and 1504 show some illustrative spectrum emission masks for comparison. Fig.14 The described processing can improve the spectrum positioning, as shown at the edges of the figure as the PSD drops from the edge of the channel bandwidth to values ​​of approximately -60 to -90 dBm per 100 kHz MBW. Thus, improved spectrum positioning can be achieved.

[0371] Although examples have been described above with respect to generating a single waveform for transmission, it will be appreciated that in some examples, the inverse process may be performed at the receiver side to (re)generate multiple symbols on the subcarriers. Figure 7 An example of the reverse process is shown and described, and based on Fig. 9 , Fig.12 and Fig.14 Additional reverse processes are also possible and within the scope of the present disclosure.

[0372] For example, about Fig. 9 The inverse process of the subband separation and extraction (e.g., separating the waveform into two or more subband waveforms) may include: for each subband waveform: demodulating the subband waveform from the second frequency; extracting the demodulated subband waveform; demodulating the extracted demodulated subband waveform from the first frequency; and converting the obtained subband waveform into a plurality of time domain symbol sequences. The first frequency and the second frequency may be as described above.

[0373] For example, about Fig.12The inverse process of subband separation and extraction (for example, separating a waveform into two or more subband waveforms) may include: dividing a single waveform into multiple partially overlapping blocks including one or more time domain symbols; converting each partially overlapping time domain symbol block to the frequency domain; dividing the resulting frequency domain symbols into multiple partially overlapping frequency domain symbol sets; and for each set: applying a window function to the frequency domain symbol set; converting the windowed frequency domain symbol set to the time domain; removing the overlapping portions from each partially overlapping time domain symbol set, and combining the resulting symbols into a subband waveform.

[0374] For example, about Fig.14 The inverse process of the subband separation and extraction (for example, separating the waveform into two or more subband waveforms) may include: for each subband waveform: demodulating the subband waveform from a third frequency; extracting the demodulated subband waveform; separating the extracted demodulated subband waveform into a plurality of partially overlapping symbol blocks, wherein each symbol block at least partially overlaps with at least one other symbol block; and for each block: converting the partially overlapping symbol block to the frequency domain; applying a window function to the frequency domain partially overlapping symbol block; converting the resulting frequency domain partially overlapping symbol block to the time domain; and removing overlapping symbols from each time domain partially overlapping symbol block, and combining the resulting symbols into a subband waveform.

[0375] Some examples may enable efficient implementation of large transforms (e.g., FFT / IFFT, DFT / IDFT) in a transparent manner, e.g., with little or no impact on the receiver side (because the transmitted waveform is not changed). Some examples may be implemented with current transforms already present in the device. Thus, some examples may avoid increasing circuit area. Some examples may provide improved spectral positioning compared to conventional waveform generation. Some examples may enable increasing the number of supported subcarriers and thereby adding new bandwidth / digital technology options with existing transform sizes, e.g., even without increasing the maximum transform size.

[0376] In some examples, an apparatus is provided that includes components for: mapping frequency domain symbols on multiple subcarriers into at least two sets, each set including symbols of at least one subcarrier among the multiple subcarriers; for each set: performing symbol-by-symbol rotation based on complex coefficient values, and converting the rotated symbols from the frequency domain to the time domain; or converting the symbols from the frequency domain to the time domain, and performing symbol-by-symbol rotation on the time domain symbols based on the complex coefficient values; inserting a cyclic prefix into each time domain symbol; concatenating the time domain symbols generated by the cyclic prefix insertion to generate a subband waveform; and performing subband filtering, interpolation, and combining based on the subband waveforms of each set in the set to generate a single waveform.

[0377] In some examples, an apparatus is provided that includes components for: separating a single waveform into two or more subband waveforms; for each subband waveform: converting the subband waveform into multiple time domain symbol sequences; removing a cyclic prefix from each of the multiple time domain symbol sequences; converting each of the resulting multiple symbols from the time domain to the frequency domain; performing a symbol-by-symbol rotation on the frequency domain symbols based on a complex coefficient value; and mapping the rotated frequency domain symbols derived from each subband waveform into a single set including multiple rotated frequency domain symbols on multiple subcarriers.

[0378] In some examples, a device is provided, comprising at least one processor and at least one memory storing instructions, which, when executed by the at least one processor, causes the device to at least: map frequency domain symbols on a plurality of subcarriers into at least two sets, each set comprising symbols of at least one subcarrier among the plurality of subcarriers; for each set: perform symbol-by-symbol rotation based on a complex coefficient value, and convert the rotated symbol from the frequency domain to the time domain; or convert the symbol from the frequency domain to the time domain, and perform symbol-by-symbol rotation on the time domain symbol based on the complex coefficient value; insert a cyclic prefix into each time domain symbol; connect the time domain symbols generated by the cyclic prefix insertion to generate a subband waveform; and perform subband filtering, interpolation, and combination based on the subband waveform of each set in the set to generate a single waveform.

[0379] In some examples, a device is provided that includes at least one processor and at least one memory storing instructions that, when executed by the at least one processor, cause the device to at least: separate a single waveform into two or more subband waveforms; for each subband waveform: convert the subband waveform into multiple time domain symbol sequences; remove a cyclic prefix from each of the multiple time domain symbol sequences; convert each of the resulting multiple symbols from the time domain to the frequency domain; perform a symbol-by-symbol rotation on the frequency domain symbols based on a complex coefficient value; and map the rotated frequency domain symbols derived from each subband waveform into a single set including multiple rotated frequency domain symbols on multiple subcarriers.

[0380] It should be understood that the references to various network functions (e.g., AMF, SMF, etc.) above may include devices that perform at least some of the functions associated with these network functions. In addition, the device including the network function may include a virtual network function instance of the network function.

[0381] It should be understood that these devices may include or be coupled to other units or modules for transmission and / or reception, such as radio components or radio heads. Although these devices are described as one entity, different modules and memories may be implemented in one or more physical or logical entities.

[0382] It should be noted that although some embodiments have been described with respect to 5G networks, similar principles may also be applied to other networks and communication systems. Thus, although certain embodiments are described above by way of example with reference to certain example architectures of wireless networks, technologies and standards, the embodiments may be applied to any other suitable form of communication system other than that shown and described herein.

[0383] It is also noted herein that while the above describes exemplifying embodiments, there are numerous variations and modifications which may be made to the disclosed solution without departing from the scope of the present invention.

[0384] As used herein, “at least one of: ” and “<at least one of a list of two or more elements>” and similar expressions (wherein a list of two or more elements is connected by “and” or “or”) mean at least any one of these elements, or at least any two or more of these elements, or at least all of these elements.

[0385] In general, various embodiments may be implemented in hardware or dedicated circuitry, software, logic, or any combination thereof. Some aspects of the disclosure may be implemented in hardware, while other aspects may be implemented in firmware or software, which may be executed by a controller, microprocessor, or other computing device, but the disclosure is not limited thereto. Although various aspects of the disclosure may be shown and described as block diagrams, flow charts, or using some other graphical representation, it is well understood that, as non-limiting examples, the boxes, devices, systems, techniques, or methods described herein may be implemented in hardware, software, firmware, dedicated circuitry or logic, general-purpose hardware or controllers or other computing devices, or some combination thereof.

[0386] As used in this application, the term "circuitry" may refer to one, more, or all of the following:

[0387] (a) hardware circuit implementation only (such as implementation only in analog and / or digital circuitry) and

[0388] (b) a combination of hardware circuitry and software such as (where applicable):

[0389] (i) a combination of analog and / or digital hardware circuits and software / firmware, and

[0390] (ii) any portion of hardware processor(s) (including digital signal processors) with software, software and memory(s) that work together to enable a device (such as a mobile phone or server) to perform various functions) and

[0391] (c) Hardware circuit(s) and / or processor(s), such as microprocessor(s) or portion(s) of microprocessor(s), that require software (e.g., firmware) to operate, but in which case the software may not be present when not required.

[0392] This definition of circuitry applies to all uses of the term in this application, including in any claims. As a further example, as used in this application, the term "circuitry" also covers an implementation of only a hardware circuit or processor (or multiple processors) or a portion of a hardware circuit or processor and its (or their) accompanying software and / or firmware. For example, if applicable to a particular claim element, the term "circuitry" also covers an integrated circuit, such as a baseband integrated circuit or processor integrated circuit for a mobile device, or a similar integrated circuit in a server, cellular network device, or other computing or network device.

[0393] The embodiments of the present disclosure may be implemented by computer software executable by a data processor of a mobile device (such as a processor entity), or by hardware, or by a combination of software and hardware. Computer software or programs (also referred to as program products) include software routines, applets and / or macros that can be stored in a data storage medium readable by any device, and they include program instructions for performing specific tasks. A computer program product may include one or more computer executable components that are configured to perform an embodiment when the program is run. One or more computer executable components may be at least one software code or a portion thereof.

[0394] In this regard, it should also be noted that any blocks of the logic flow shown in the Figures may represent program steps, or interconnected logic circuits, blocks and functions, or a combination of program steps and logic circuits, blocks and functions. The software may be stored on physical media, such as memory chips or memory blocks implemented within a processor, magnetic media (such as hard disks or floppy disks), and optical media (such as, for example, DVDs and their data variants, CDs). Physical media are non-transitory media. .

[0395] The term "non-transitory" as used herein refers to the limitations of the medium itself (ie, tangible, not a signal), not the limitations of data storage persistence (eg, RAM vs. ROM).

[0396] The memory may be of any type suitable for the local technical environment and may be implemented using any suitable data storage technology, such as semiconductor-based memory devices, magnetic memory devices and systems, optical memory devices and systems, fixed memory, and removable memory. The data processor may be of any type suitable for the local technical environment and may include, as non-limiting examples, one or more of the following: a general-purpose computer, a special-purpose computer, a microprocessor, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), an FPGA, a gate-level circuit, and a processor based on a multi-core processor architecture.

[0397] Embodiments of the present disclosure may be practiced in various components, such as integrated circuit modules. The design of integrated circuits is generally a highly automated process. Complex and powerful software tools are available to convert logic level designs into semiconductor circuit designs for etching and formation on semiconductor substrates.

[0398] The scope of protection sought by various embodiments of the present disclosure is defined by the independent claims. Embodiments and features described in this specification that do not belong to the scope of the independent claims (if any) should be interpreted as examples that help understand the various embodiments of the present disclosure.

[0399] The foregoing description has provided, by way of non-limiting examples, a complete and informative description of exemplary embodiments of the present disclosure. However, various modifications and adaptations may become apparent to those skilled in the relevant art when the foregoing description is read in conjunction with the accompanying drawings and the appended claims. However, all such and similar modifications of the teachings of the present disclosure will still fall within the scope of the present invention as defined in the appended claims. Indeed, there are additional embodiments that include a combination of one or more embodiments with any other embodiments previously discussed.

Claims

1. An apparatus for use in a communication network, comprising means for: Mapping frequency domain symbols on a plurality of subcarriers into at least two sets, each set including symbols of at least one subcarrier of the plurality of subcarriers; For each collection: Performing symbol-by-symbol rotation based on complex coefficient values ​​and converting the rotated symbols from the frequency domain to the time domain; or converting the symbols from the frequency domain to the time domain and performing symbol-by-symbol rotation on the time domain symbols based on the complex coefficient values; Inserting a cyclic prefix into each time domain symbol; concatenating the time domain symbols generated by cyclic prefix insertion to generate a sub-band waveform; as well as Subband filtering, interpolation, and combining are performed based on the subband waveforms of each of the sets to generate a single waveform.

2. The apparatus of claim 1 , wherein the two or more sets include one or more active sets and one or more inactive sets, wherein the one or more active sets contain mapped frequency domain symbols, and wherein the one or more inactive sets do not contain mapped frequency domain symbols, and Wherein converting the rotated symbols from the frequency domain to the time domain comprises: An inverse fast Fourier transform is applied to each of the rotated symbols.

3. The apparatus according to any one of the preceding claims, wherein the complex coefficient value is φ m，b =exp(-2jπθ m，b ),in: L is the number of subcarriers, M is the number of sets, b is the index of the symbol, m is an index into the set and is an integer value ranging from 0 to M-1, and N CP,k is the length of the cyclic prefix.

4. The apparatus of any one of the preceding claims, wherein performing sub-band filtering, interpolation, and combining based on the sub-band waveforms to generate the single waveform comprises: For each collection: modulating the sub-band waveform to a first frequency; interpolating the modulated sub-band waveform; as well as modulating the interpolated modulated sub-band waveform to a second frequency; and The resulting interpolated and modulated sub-band waveforms for each set are combined into a single waveform.

5. The device according to claim 4, wherein the first frequency is c m / M, and the second frequency is f m =f SCS L / M[(M-1) / 2-m]-cm, where: f SCS is the subcarrier spacing frequency of the generated waveform; L is the number of subcarriers, M is the number of sets, m is the number of the set and is an integer value ranging from 0 to M-1, and c m is an implementation specific parameter used to control the spectrum of the sub-band waveform.

6. The apparatus of any one of claims 1 to 3, wherein performing the sub-band filtering, interpolation, and combining based on the sub-band waveform to generate the waveform comprises: For each collection: dividing the symbols of the sub-band waveform into a plurality of overlapping blocks; converting the plurality of overlapping blocks to the frequency domain; applying a window function to each of the overlapping blocks in the frequency domain to generate a plurality of windowed blocks; converting the plurality of windowed blocks from the frequency domain to the time domain; and discarding a subset of each windowed block in the time domain; as well as The resulting time-domain windowed blocks for each of the sets are combined into a single waveform.

7. The apparatus of any one of claims 1 to 3, wherein performing the sub-band filtering, interpolation, and combining based on the sub-band waveform to generate the waveform comprises: For each collection: converting the sub-band waveforms from serial to parallel, wherein the resulting parallel components of the sub-band waveforms are at least partially overlapped; converting a plurality of at least partially overlapping parallel components of the sub-band waveform into the frequency domain; applying a window function to the frequency-domain parallel overlapping components of the sub-band waveforms; removing overlapping blocks from the windowed frequency-domain parallel overlapping components of the sub-band waveforms and converting the resulting parallel components into serial sub-band waveforms; interpolating the serial sub-band waveform; and modulating the interpolated serial sub-band waveform to a third frequency; and The resulting interpolated serial sub-band waveforms of the modulation for each set are combined into a single waveform.

8. The device according to claim 7, wherein the third frequency is f m =f SCS L / M[(M-1) / 2-m], where: f SCS is the subcarrier spacing frequency of the single waveform; L is the number of subcarriers, M is the number of sets, and m is the number of the set, and is an integer value varying between 0 and M-1.

9. An apparatus for use in a communication network, comprising means for: Splitting a single waveform into two or more sub-band waveforms; For each subband waveform: Converting the sub-band waveform into a plurality of time-domain symbol sequences; removing a cyclic prefix from each of the plurality of time-domain symbol sequences; converting each symbol of the obtained plurality of symbols from the time domain to the frequency domain; performing a symbol-by-symbol rotation on the frequency domain symbols based on complex coefficient values; and mapping the rotated frequency domain symbols derived from each subband waveform into a single set including a plurality of rotated frequency domain symbols on a plurality of subcarriers.

10. A method for use in a communication network, comprising: Mapping frequency domain symbols on a plurality of subcarriers into at least two sets, each set including symbols of at least one subcarrier of the plurality of subcarriers; For each collection: Performing symbol-by-symbol rotation based on complex coefficient values ​​and converting the rotated symbols from the frequency domain to the time domain; or converting the symbols from the frequency domain to the time domain and performing symbol-by-symbol rotation on the time domain symbols based on the complex coefficient values; Inserting a cyclic prefix into each time domain symbol; concatenating the time domain symbols generated by the cyclic prefix insertion to generate a sub-band waveform; as well as Subband filtering, interpolation, and combining are performed based on the subband waveforms of each of the sets to generate a single waveform.

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