EP4666770A1

EP4666770A1 - Method and apparatus for papr reduction for repetition in frequency domain in mobile communications

Info

Publication number: EP4666770A1
Application number: EP24756164.0A
Authority: EP
Inventors: Junqiang CHENG; Chenmeng LI; Tao Chen; Min LEI; Pei-Kai Liao
Original assignee: MediaTek Singapore Pte Ltd
Current assignee: MediaTek Singapore Pte Ltd
Priority date: 2023-02-17
Filing date: 2024-02-06
Publication date: 2025-12-24
Also published as: CN120693950A; WO2024169791A1

Abstract

Examples pertaining to peak-to-average power ratio (PAPR) reduction for repetition in frequency domain in mobile communications are described. An apparatus generates a first sequence and a second sequence. The second sequence is a repetition of the first sequence in frequency domain. The apparatus changes a value of at least one element in at least one of the first sequence and the second sequence and transmits a transmission signal comprising at least the first sequence and the second sequence.

Description

METHOD AND APPARATUS FOR PAPR REDUCTION FOR REPETITION IN FREQUENCY DOMAIN IN MOBILE COMMUNICATIONS

CROSS REFERENCE TO RELATED PATENT APPLICATION (S)
The present disclosure is part of a non-provisional application claiming the priority benefit of PCT Application No. PCT/CN2023/076847, filed 17 February 2023, and PCT Application No. PCT/CN2023/085577, filed 31 March 2023. The contents of aforementioned applications are herein incorporated by reference in their entirety.

TECHNICAL FIELD

The present disclosure is generally related to mobile communications and, more particularly, to peak-to-average power ratio (PAPR) reduction for an apparatus implementing repetition in frequency domain in mobile communications.

BACKGROUND

Unless otherwise indicated herein, approaches described in this section are not prior art to the claims listed below and are not admitted as prior art by inclusion in this section.
Peak-to-average power ratio (PAPR) is a critical parameter in wireless communication system. The signal with high PAPR may cause excessive intermodulation distortion of the power amplifier. The transmission with low PAPR may lead to better signal detection at the receiver side. Additionally, some mechanism in wireless communication system may result in high PAPR issue. For example, signal repetition in frequency domain may increase the PAPR due to superposition in time domain, and a longer signal in frequency domain may also increase the PAPR.
Therefore, the methods and apparatus for PAPR reduction, especially when a signal is repeated in frequency domain, are needed to solve the issues caused by high PAPR.

SUMMARY

The following summary is illustrative only and is not intended to be limiting in any way. That is, the following summary is provided to introduce concepts, highlights, benefits and advantages of the novel and non-obvious techniques described herein. Select implementations are further described below in the detailed description. Thus, the following summary is not intended to identify essential features of the claimed subject matter, nor is it intended for use in determining the scope of the claimed subject matter.
An objective of the present disclosure is to propose solutions or schemes that address the aforementioned issues pertaining to PAPR reduction for an apparatus implementing signal or sequence repetition in frequency domain in mobile communications.
In one aspect, a method may involve an apparatus generating a first sequence and a second sequence, wherein the second sequence is a repetition of the first sequence in frequency domain; changing, by the processor, a value of at least one element in at least one of the first sequence and the second sequence; and transmitting a transmission signal comprising at least the first sequence and the second sequence.
In one aspect, a method may involve an apparatus generating a first sequence and a second sequence, wherein the second sequence is a repetition of the first sequence in frequency domain; changing content of at least one element in at least one of the first sequence and the second sequence; and transmitting a transmission signal comprising at least the first sequence and the second sequence.
It is noteworthy that, although description provided herein may be in the context of certain radio access technologies, networks and network topologies such as Long-Term Evolution (LTE) , LTE-Advanced, LTE-Advanced Pro, 5th Generation (5G) , New Radio (NR) , Internet-of-Things (IoT) and Narrow Band Internet of Things (NB-IoT) , Industrial Internet of Things (IIoT) , and 6th Generation (6G) , the proposed concepts, schemes and any variation (s) /derivative (s) thereof may be implemented in, for and by other types of radio access technologies, networks and network topologies. Thus, the scope of the present disclosure is not limited to the examples described herein.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings are included to provide a further understanding of the disclosure and are incorporated in and constitute a part of the present disclosure. The drawings illustrate implementations of the disclosure and, together with the description, serve to explain the principles of the disclosure. It is appreciable that the drawings are not necessarily in scale as some components may be shown to be out of proportion than the size in actual implementation in order to clearly illustrate the concept of the present disclosure.
FIG. 1 is a diagram depicting an example scenario of signal or sequence repetition in frequency domain in accordance with implementations of the present disclosure.
FIG. 2 is a diagram depicting an example scenario of a signal processing chain in accordance with implementations of the present disclosure.
FIG. 3 is a diagram depicting an example scenario of a signal processing chain in accordance with implementations of the present disclosure.
FIG. 4 is a diagram depicting an example scenario of applying multiple phase adjustment sequences or scrambling sequences to at least the repetitions in accordance with implementations of the present disclosure.
FIG. 5 is a diagram depicting an example scenario of applying one phase adjustment sequence or one scrambling sequence to at least the repetitions in accordance with implementations of the present disclosure.
FIG. 6 is a diagram depicting an example communication system having an example communication apparatus and an example network apparatus in accordance with an implementation of the present disclosure.
FIG. 7 is a diagram depicting an example process in accordance with an implementation of the present disclosure.
FIG. 8 is a diagram depicting another example process in accordance with an implementation of the present disclosure.
DETAILED DESCRIPTION OF PREFERRED IMPLEMENTATIONS
Detailed embodiments and implementations of the claimed subject matters are disclosed herein. However, it shall be understood that the disclosed embodiments and implementations are merely illustrative of the claimed subject matters which may be embodied in various forms. The present disclosure may, however, be embodied in many different forms and should not be construed as limited to the exemplary embodiments and implementations set forth herein. Rather, these exemplary embodiments and implementations are provided so that description of the present disclosure is thorough and complete and will fully convey the scope of the present disclosure to those skilled in the art. In the description below, details of well-known features and techniques may be omitted to avoid unnecessarily obscuring the presented embodiments and implementations.
Overview
Implementations in accordance with the present disclosure relate to various techniques, methods, schemes and/or solutions pertaining to PAPR reduction for an apparatus performing signal or sequence repetition in frequency domain in mobile communications. According to the present disclosure, a number of possible solutions may be implemented separately or jointly. That is, although these possible solutions may be described below separately, two or more of these possible solutions may be implemented in one combination or another.
Signal or sequence repetition in frequency domain may be used in some cases. As an example, to meet the occupied channel bandwidth (OCB) requirement for transmission on an unlicensed band, an apparatus (i.e., a transmitter, such as a communication apparatus, a user equipment (UE) , or a network node) may determine to perform signal or sequence repetition in frequency domain. As another example, to achieve a diversity gain or to increase the transmission power when there is a power spectrum density (PSD) limitation, the apparatus may be configured to perform signal or sequence repetition in frequency domain.
When a signal or a sequence to be transmitted by the apparatus is repeated in frequency domain, the signal repetition in frequency domain will lead to signal superposition in time domain thus further results in a high PAPR. To solve this problem, a value based cyclic shift method and a content based cyclic shift method are proposed in the present disclosure and will be respectively introduced in the following paragraphs.
In some implementations, the apparatus may perform value based cyclic shift on the signals or sequences to be transmitted (including the original signal or sequence and one or more repetitions thereof) , or perform value based cyclic shift among the repetitions of the original signal or the original sequence to be transmitted. In some implementations, the value based cyclic shift operation may comprise a phase adjustment operation.
In some implementations, the apparatus may perform content based cyclic shift on the signals or sequences to be transmitted (including the original signal or sequence and one or more repetitions thereof) , or perform content based cyclic shift among the repetitions of the original signal or the original sequence to be transmitted. In some implementations, the content based cyclic shift operation may comprise a scrambling operation. In some implementations, the content based cyclic shift operation may comprise a value change operation and/or a location change operation.
FIG. 1 illustrates an example scenario 100 of signal or sequence repetition in frequency domain in accordance with implementations of the present disclosure. In this example scenario, a sidelink synchronization signal block (S-SSB) is the original signal or sequence to be transmitted and repeated, and there are (N-1) repetitions of the original S-SSB in frequency domain.
Assuming that the original S-SSB is the first transmitted sequence (denoted as Tx_1) , the first repetition of the S-SSB may be the secondly transmitted sequence (denoted as Tx_2) , the second repetition of the S-SSB may be the thirdly transmitted sequence (denoted as Tx_3) , the (N-1) -th repetition of the S-SSB may be the last transmitted sequence (denoted as Tx_N) and the rest may be deduced by analogy.
In some implementations, one or more gaps with a length L, denoted as Gap L in FIG. 1, may be inserted or arranged between the sequences. Note that in some implementations, there may be no gap inserted or arranged between the sequences to be transmitted. The lengths of the gaps may be different or the same between the repetitions.
In some implementations, to achieve PAPR reduction, the apparatus (e.g., the transmitter) may perform the value based cyclic shift (e.g., phase adjustment) on the repetitions to generate the repetitions with phase adjustment as denoted in FIG. 1. Note that in some implementations, the apparatus may also perform the value based cyclic shift (e.g., phase adjustment) on the original signal or sequence to be repeated.
In some implementations, to achieve PAPR reduction, the apparatus (e.g., the transmitter) may perform the content based cyclic shift (e.g., scrambling operation) on the repetitions to generate the repetitions with scrambling as denoted in FIG. 1. Note that in some implementations, the apparatus may also perform the content based cyclic shift (e.g., scrambling operation) on the original signal or sequence to be repeated.
To be more specific, in an aspect of the present disclosure, the apparatus may generate a first sequence (or signal) and a second sequence (or signal) , wherein the second sequence is a repetition of the first sequence in frequency domain. The second sequence may comprise the same data information as the first sequence. The apparatus may change a value of at least one element in at least one of the first sequence and the second sequence and transmit a transmission signal comprising at least the first sequence and the second sequence.
In some implementations, the value may be changed by performing a value based cyclic shift or a phase adjustment (hereinafter called phase adjustment for brevity) on the element in at least one of the first sequence and the second sequence. As an example, assuming that an original sequence comprises four elements {A, B, C, D}, and after one repetition and before changing value (s) or performing the phase adjustment, the signal to be transmitted comprises at least the eight elements {A, B, C, D, A, B, C, D} . After changing value (s) or performing the phase adjustment, the eight elements in the signal to be transmitted may become {A, B, C, D, A’, B’, C’, D’} , where at least one of the following conditions will be satisfied: the element A’ and the element A have different values or phases, the element B’ and the element B have different values or phases, the element C’ and the element C have different values or phases, and the element D’ and the element D have different values or phases. In this manner, the regularity after repetition is destroyed.
In some implementations, the element A’ (as well as the element B’, the element C’ and the element D’) may be a new value generated out of {A, B, C, D} (i.e., A’ does not belong to {A, B, C, D} ) . In some implementations, the element A’ may be not equal to A but may belong to {B, C, D} . Note that the present invention is not limited to any specific way of implementations.
In some implementations, the changing of the value of at least one element in at least one of the first sequence and the second sequence may comprise applying a first phase adjustment sequence to the first sequence and applying a second phase adjustment sequence to the second sequence. The first phase adjustment sequence and the second phase adjustment sequence may be different.
In some implementations, the first sequence may correspond to a first repetition index and the second sequence may correspond to a second repetition index. In some implementations, the first phase adjustment sequence may be generated based on the first repetition index and the second phase adjustment sequence may be generated based on the second repetition index.
As an example, assuming that the original signal or sequence may be a complex sequence (e.g., a sequence of complex numbers) and may be represented by S with a length of M. After (N-1) repetition in frequency domain, the signal to be transmitted may be represented as:
After performing phase adjustment, the signal to be transmitted may be represented as:
where Θ_n is the phase adjustment sequence multiplied on the n-th repetition.
In some implementations, the phase adjustment sequence Θ_n may be a sequence with perfect auto-correlation (e.g., a Zadoff–Chu (ZC) sequence) and with a root index n, where the value of root index may be set as n=0, 1, … (N-1) , as the repetition index. That is, in some implementations, the root index (or any parameter) for generating the phase adjustment sequences may be bound to the repetition index, wherein the repetition indexes may be the numbers or values utilized to distinguish between original sequence and repetition or distinguish between different repetitions.
Therefore, in some implementations, the phase adjustment sequence Θ_n is to be applied on the n-th repetition. As an example, the n-th repetition is multiplied by the phase adjustment sequence Θ_n as illustrated in Eq. (2) to perform phase adjustment.
In some implementations, the phase adjustment sequence Θ_n may be expressed as:
where
Note that in some implementations, in an event that the counting of root index starts from 0 (thus, the value of root index n is within the range from 0 to (N-1) ) , the repetition index may start from 0 as well. With this setting, the phase of the original sequence (e.g., with the repetition index n being set to 0) remains unchanged even after the corresponding phase adjustment sequence (e.g., Θ₀) is applied, since α₀ (m) =0 when n=0.
Note further that in some other implementations, in an event that the counting of root index starts from 1 (thus, the value of root index n is within the range from 1 to N) , and the repetition index may start from 1 as well. With this setting, the phase of the original sequence (e.g., with the repetition index n being set to 1) may be changed after the corresponding phase adjustment sequence (e.g., Θ₁) is applied.
In some implementations, the first sequence may correspond to a first identity and the second sequence may correspond to a second identity, where the identity may be a sidelink identity or a synchronization identity, such as the identity assigned to each sequence comprised in a secondary synchronization sequence (SSS) . In some implementations, the first phase adjustment sequence may be generated based on the first identity and the second phase adjustment sequence may be generated based on the second identity.
In some implementations, at least one of the first phase adjustment sequence and the second phase adjustment sequence may be predefined, preconfigured or indicated as a sequence with an ideal auto-correlation, a sequence with an auto-correlation satisfying a specific requirement or a sequence optimized based on the first sequence in an event that the first sequence is the original sequence to be repeated.
In some implementations, the phase adjustment operation may be a complex-level operation, that is, the first phase adjustment sequence or the second phase adjustment sequence may comprise a plurality of complex numbers.
In some implementations, the changing of the value of at least one element in at least one of the first sequence and the second sequence may comprise applying a phase adjustment sequence to the first sequence and the second sequence, where a length of the phase adjustment sequence may be equal to a summation of a length of the first sequence, a length of the second sequence and a length of a gap between the first sequence and the second sequence (if there is a gap arranged between the first sequence and the second sequence) .
In some implementations, the phase adjustment sequence may be predefined, preconfigured or indicated as a sequence with an ideal auto-correlation, a sequence with an auto-correlation satisfying a specific requirement or a sequence optimized based on the first sequence in an event that the first sequence is the original sequence to be repeated.
In some implementations, the phase adjustment operation may be a complex-level operation, that is, the phase adjustment sequence comprises a plurality of complex numbers.
FIG. 2 illustrates an example scenario 200 of a signal processing chain in accordance with implementations of the present disclosure. The data signal (or data sequence) (e.g., Data denoted in FIG. 2) to be transmitted by an apparatus may be the signal with one or more repetitions in frequency domain.
In some implementations, a sequence of operations performed on the data signal Data to be transmitted may comprise scrambling 210, modulation 220, phase adjustment 230, layer mapping 240, transform precoding 250, precoding 260 and resource block mapping 270, where an output signal S_TX may be generated after the resource block mapping 270. In some implementations, the phase adjustment sequence generation 280 may be involved in signal processing chain to provide one or more phase adjustment sequences (or vectors) to assist phase adjustment operation (i.e., the value based cyclic shift operation) in phase adjustment 230.
In some implementations, the operations of phase adjustment 230 and phase adjustment sequence generation 280 may be inserted/implemented in the signal processing chain after the modulation 220 or before the operation of transform precoding 250, wherein the transform precoding may be the inverse fast Fourier transform (IFFT) .
In some implementations, the sequence or signal (e.g., the data signal or sequence Data in FIG. 2) to be repeated in frequency domain may be any regular or irregular sequence or signal, such as an m sequence, a ZC sequence, a Gold sequence, a random quadrature amplitude modulation (QAM) or phase shift keying (PSK) sequence or signal, etc. For the case of repetition of the sequence or signal in frequency domain, one or more phase adjustment sequences or vectors may be used on repetition (s) , or may even be used on the original sequence or signal to be repeated, as introduced above. The phase adjustment sequence or vector may be configured or preconfigured, or may be real-time indicated.
In some implementations, the phase adjustment sequence or vector may be generated using different options based on an initial phase adjustment sequence or vector.
In addition, in some implementations, one or more gaps may be inserted or added between the original sequence and repetition or between the repetitions.
For example, the original sequence or signal to be repeated in frequency domain may be presented as:
S= {S (0) , S (1) , …, S (M-1) } Eq. (5)
where M is the length of the original sequence or signal.
The sequence or signal after the repetition (s) of S in frequency domain and before adding the gap (s) may be represented as:
S_R= {S_R (0) , S_R (1) , …, S_R (N_R-1) } Eq. (6)
where N_R is the length of the sequence or signal after the repetition (s) .
After adding one or more gaps to S_R, regardless of the pattern of the gaps, the sequence or signal may be represented as:
S_RG= {S_RG (0) , S_RG (1) , …, S_RG (N_RG-1) } Eq. (7)
where N_RG is the length of the repeated and gapped sequence or signal. For the method of repetition with phase adjustment proposed in this disclosure, the initial phase adjustment sequence may be represented as:
Θ_ini= {e^jα (0), e^jα (1), …, e^jα (R-1)} Eq. (8)
with a length of R, where A= {α (0) , α (1) , …, α (R-1) } is the vector in the index of Θ_ini. Note that the root index or the repetition index may be omitted here for brevity, and in some implementations, the initial phase adjustment sequence may also be represented as the phase adjustment sequence Θ_n in Eq. (4) .
In some implementations, A may be set as any sequence or vector, such as an m sequence, a ZC sequence, a random sequence, a sequence evenly distributed on[0, 2π) or [0, π) , or any other sequence. The phase adjustment sequence Θ may be represented as:
(or) , where 1_K×1 may be a vector of ones with a length of K and may be the Kronecker product, depending on the generating method option being selected.
In some implementations, the phase adjustment mechanism may be applied at different timing, either after repeating and before adding the gap (s) or after both repeating and adding the gap (s) . Therefore, the phase adjustment operation may be represented as either ΘS_R or ΘS_RG.
In some implementations, in an event that there is no gap (s) between the repetitions, the phase adjustment operation may be ΘS_R, or the phase adjustment operation may be understood as ΘS_RG, where the gap is of length of zero. Regardless of which timing is the phase adjustment mechanism being applied, the sequence or signal in frequency domain after repeating, adding the gap (s) and phase adjustment may be represented as S_RG′.
In some implementations, at receiver side, upon receiving the transmission signal comprising the sequence or signal undergoing repetition (with or without gap) in frequency domain and phase adjustment, such as the aforementioned sequence or signal S_RG′ from the transmitter, the effect of phase adjustment may be removed based on one or more phase adjustment sequences corresponding to the phase adjustment sequences utilized by the transmitter. After removing the phase adjustment in the received signal (e.g., the received signal comprising the original signal and one or more repetitions transmitted by the transmitter) , the output may be used for equalization.
In another aspect of the present disclosure, the apparatus may generate a first sequence (or signal) and a second sequence (or signal) , wherein the first sequence (or signal) and the second sequence (or signal) may respectively comprise a plurality of elements, and the second sequence is a repetition of the first sequence in frequency domain. The second sequence may comprise the same data information as the first sequence. The apparatus may change content of at least one element in at least one of the first sequence and the second sequence, and transmit a transmission signal comprising at least the first sequence and the second sequence.
In some implementations, the changing of the content (i.e., the content based cyclic shift) may comprise changing a value of at least one element in at least one of the first sequence and the second sequence and/or changing locations of the elements in at least one of the first sequence and the second sequence.
In some implementations, the content of the at least one element may be changed by performing a content based cyclic shift or a scrambling operation (hereinafter called scrambling operation for brevity) on at least one of the first sequence and the second sequence. As an example, assuming that an original sequence comprises four elements {A, B, C, D} , and after one repetition and before changing the content or performing the scrambling operation on the elements, the signal to be transmitted comprises at least the eight elements {A, B, C, D, A, B, C, D} . After changing content or performing the scrambling operation on the elements, an order or an arrangement of the eight elements in the signal to be transmitted may become {A, B, C, D, B, A, D, C} . That is, the four elements in the repetition are reordered or the locations of the four elements in the repetition are changed.
In some implementations, after changing content or performing the scrambling operation on the elements, the eight elements in the signal to be transmitted may become {A, B, C, D, B, D, A, A} . That is, the four elements in the repetition may be randomly selected from the four elements {A, B, C, D} comprised in the original sequence when performing the content change or the scrambling operation. As another example, after changing content or performing the scrambling operation on the elements, the eight elements in the signal to be transmitted may become {A, B, C, D, B, B, B, B} . That is, some elements may be repeated and/or some elements may not exist in the repetition. Note that the present invention is not limited to any specific way of implementations.
Note that in some implementations, after the content based cyclic shift or the scrambling operation, several different results may be obtained. In some implementations, after the content based cyclic shift or the scrambling operation, only the locations of the elements may be changed and the values of the elements in the original sequence and its repetition (s) may remain unchanged. In some implementations, after the content based cyclic shift or the scrambling operation, the value of the elements may be changed, and the locations of the elements may remain unchanged. In some implementations, after the content based cyclic shift or the scrambling operation, the value and the locations of the elements may be changed.
FIG. 3 illustrates an example scenario 300 of a signal processing chain in accordance with implementations of the present disclosure. The data signal (or data sequence) Data to be transmitted by an apparatus may be the signal with one or more repetitions in frequency domain.
In some implementations, a sequence of operations performed on the data signal Data to be transmitted may comprise scrambling 310, modulation 320, layer mapping 340, transform precoding 350, precoding 360 and resource block mapping 370, where an output signal S_TX may be generated after the resource block mapping 370. In some implementations, the scrambling sequence generation 380 may be involved in signal processing chain to provide one or more scrambling sequences (or vectors) to assist scrambling operation (i.e., the content based cyclic shift operation) .
Note that the scrambling 310 may be performed on both the original sequence and one or more repetitions thereof, and the scrambling sequences may be generated differently based on different purposes, including for normal data scrambling and for PAPR reduction. As an example, the scrambling sequence generation 380 may generate a first type of scrambling sequences for scrambling the original data sequence, as a transmitter usually does for normal data scrambling. The scrambling sequence generation 380 may generate a second type of scrambling sequences for scrambling the original data sequence (or, the original data sequence that has been scrambled by the first type of scrambling sequence) and/or its repetitions for PAPR reduction.
In some implementations, since the content (comprising the value, the order or the arrangement) of the elements in the signal to be transmitted is changed, after the modulation 320, the constellation points corresponding to the elements among the repetitions or the constellation points corresponding to the elements between the original sequence and at least one repetition will be different as well. In this manner, the regularity after repetition is destroyed.
In some implementations, the changing of the content of at least one element in at least one of the first sequence and the second sequence may comprise applying a first scrambling sequence to the first sequence and applying a second scrambling sequence to the second sequence. The first scrambling sequence and the second scrambling sequence may be different.
In some implementations, the first sequence may correspond to a first repetition index and the second sequence may correspond to a second repetition index, wherein the repetition indexes may be the numbers or values utilized to distinguish between original sequence and repetition or distinguish between repetitions. In some implementations, the first scrambling sequence may be generated based on the first repetition index and the second scrambling sequence may be generated based on the second repetition index.
In some implementations, the first sequence may correspond to a first identity and the second sequence may correspond to a second identity, where the identity may be a sidelink identity or a synchronization identity, such as the identity assigned to each sequence comprised in the SSS. In some implementations, the first scrambling sequence may be generated based on the first identity and the second scrambling sequence may be generated based on the second identity.
As an example, assuming that original signal (which may be a bit sequence) with a length of M may be represented as b (i) (where 0≤i≤M-1) , e.g., b (0) , …, b (M-1) , after (N-1) repetition in frequency domain, the signal to be transmitted may be represented as:
where b₁ (i) is the original sequence, b_N (i) is the (N-1) -th repetition and L is the length of gap between two consecutive sequences.
After PAPR reduction, the signal to be transmitted may be represented as:
where f (·) is a function to reduce the PAPR of its input, n is the repetition index and, in this example, n =1, …N.
In some implementations, when the PAPR reduction is achieved via a scrambling operation, the signal to be transmitted may be represented as:
where c_n (i) is the scrambling sequence applied on n-th repetition.
In some implementations, the operation in Eq. (12) may be regarded as an exclusive or (XOR) logical operation. That is, in some implementations, the scrambling operation may be carried out by performing the XOR operation, where one input of the XOR operation is the repetition (or the original sequence) and the other input of the XOR operation is the corresponding scrambling sequence.
In some implementations, the scrambling sequence c_n (i) may be generated with different initial scrambling seeds for different repetitions. In some implementations, the initial scrambling seeds may be related to or bound to the repetition index or the identity (e.g., the sidelink identity or a synchronization identity) as described above.
In some implementations, the scrambling operation may be a bit-level operation, that is, the original sequence or signal and its repetitions may be bit sequences, and the first scrambling sequence or the second scrambling sequence may comprise a plurality of binary values.
In some implementations, at least one of the first scrambling sequence and the second scrambling sequence may be predefined, preconfigured or indicated as a pseudo-random sequence.
In some implementations, the changing of the content of at least one element in at least one of the first sequence and the second sequence may comprise applying a scrambling sequence to the first sequence and the second sequence.
In some implementations, a length of the scrambling sequence is equal to a summation of a length of the first sequence, a length of the second sequence and a length of a gap between the first sequence and the second sequence.
In some implementations, the scrambling sequence is predefined, preconfigured or indicated as a pseudo-random sequence.
In some implementations, the scrambling sequence may comprise a plurality of binary values.
FIG. 4 illustrates an example scenario 400 of applying multiple phase adjustment sequences or scrambling sequences to at least the repetitions in accordance with implementations of the present disclosure, where the length of one phase adjustment sequence or the length of one scrambling sequence is set to the length of the corresponding signal or sequence (e.g., the original sequence, or its repetition) to be adjusted in phase or to be scrambled.
In some implementations, the number of scrambling sequences (or the number of phase adjustment sequences) generated to assist the scrambling operation (or the phase adjustment) may be equal to the number of sequences to be transmitted. As an example, as shown in FIG. 4, assuming that there are N sequences (including the original sequence (denoted as Tx_1) and its repetitions (denoted as Tx_2 to Tx_N) ) comprised in the transmission signal to be transmitted, N scrambling sequences (or N phase adjustment sequences) may be generated.
The N scrambling sequences (or N phase adjustment sequences) are respectively applied to the corresponding sequence in the transmission signal. The one-to-one relationships between each sequence in the transmission signal and the corresponding scrambling sequence (or the corresponding phase adjustment sequence) are illustrated in FIG. 4 as the links drawn with dotted lines.
Assuming that a length of the original signal and its repetition is M (e.g., M bits) and a length of the gap is L, a length of each scrambling sequences (or each phase adjustment sequences) may be M and a length of the transmission signal may be [N*M+ (N-1) *L] .
In some implementations, as illustrated above, instead of applying multiple phase adjustment sequences or scrambling sequences, there may be one scrambling sequence (or one phase adjustment sequence) generated to assist the scrambling operation (or the phase adjustment) . That is, the sequences generated after repetition and to be transmitted may be regarded as one component when applying the scrambling sequence (or applying the phase adjustment sequence) .
FIG. 5 illustrates an example scenario 500 of applying one phase adjustment sequence or one scrambling sequence to at least the repetitions in accordance with implementations of the present disclosure, where the length of the phase adjustment sequence or the scrambling sequence is set to the overall length of the signal to be transmitted (i.e., the transmissions signal, including the original signal or sequence and its repetition) .
As shown in FIG. 5, assuming that there are N sequences (including the original sequence (denoted as Tx_1) and its repetitions (denoted as Tx_2 to Tx_N ) ) comprised in the transmission signal to be transmitted, one scrambling sequences (or one phase adjustment sequence) may generated to assist the scrambling operation (or the phase adjustment) , and a length of the scrambling sequences (or the phase adjustment sequence) may be [N*M+ (N-1) *L] .
Note that although there are some gaps inserted in the transmission signal in the example scenarios as illustrated in FIG. 4 and FIG. 5, in other implementations, there may also be no gap inserted in the transmission signal. One main difference between those different implementations may be the length of the transmission signal and the corresponding scrambling sequence (or phase adjustment sequence) .
In addition, in some implementations, the phase adjustment sequence or the scrambling sequence may be generated to match the length of the repeated sequence based on some rules. The rules may be (pre-) configured or indicated. Specifically, the rules may be set to include, for example, the phase adjustment sequence (or, the scrambling sequence length) equals to the total length of the repeated sequence without consideration of the gap between repetitions, or the phase adjustment sequence (or, the scrambling sequence length) equals to the total length of the repeated sequence with consideration of the gap between repetitions, or the phase adjustment sequence (or, the scrambling sequence length) may be set as a length of occupied channel bandwidth, or specific channel bandwidth (e.g., 20 megahertz (MHz) ) and numerology. The length mentioned here may be regarded as the number of resource element (RE) in frequency domain.
In addition, in some implementations, the phase adjustment or the scrambling operation may be performed during and/or after performing the repetition (s) .
Illustrative Implementations
FIG. 6 illustrates an example communication system 600 having an example communication apparatus 610 and an example network apparatus 620 in accordance with an implementation of the present disclosure. Each of the communication apparatus 610 and the network apparatus 620 may perform various functions to implement schemes, techniques, processes and methods described herein pertaining to PAPR reduction for repetition in frequency domain in mobile communications, including scenarios/schemes described above as well as the process 700 and the process 800 described below.
The communication apparatus 610 may be a part of an electronic apparatus, which may be a UE such as a portable or mobile apparatus, a wearable apparatus, a wireless communication apparatus or a computing apparatus. For instance, the communication apparatus 610 may be implemented in a smartphone, a smartwatch, a personal digital assistant, a digital camera, or a computing equipment such as a tablet computer, a laptop computer or a notebook computer. The communication apparatus 610 may also be a part of a machine type apparatus, which may be an IoT, NB-IoT, or IIoT apparatus such as an immobile or a stationary apparatus, a home apparatus, a wire communication apparatus or a computing apparatus. For instance, the communication apparatus 610 may be implemented in a smart thermostat, a smart fridge, a smart door lock, a wireless speaker or a home control center. Alternatively, the communication apparatus 610 may be implemented in the form of one or more integrated-circuit (IC) chips such as, for example and without limitation, one or more single-core processors, one or more multi-core processors, one or more reduced-instruction set computing (RISC) processors, or one or more complex-instruction-set-computing (CISC) processors. The communication apparatus 610 may include at least some of those components shown in FIG. 6 such as a processor 612, for example. The communication apparatus 610 may further include one or more other components not pertinent to the proposed scheme of the present disclosure (e.g., internal power supply, display device and/or user interface device) , and, thus, such component (s) of the communication apparatus 610 are neither shown in FIG. 6 nor described below in the interest of simplicity and brevity.
The network apparatus 620 may be a part of a network device, which may be a network node such as a satellite, a base station, a small cell, a router or a gateway. For instance, the network apparatus 620 may be implemented in an eNodeB in an LTE network, in a gNB in a 5G/NR, IoT, NB-IoT or IIoT network or in a satellite or base station in a 6G network. Alternatively, the network apparatus 620 may be implemented in the form of one or more IC chips such as, for example and without limitation, one or more single-core processors, one or more multi-core processors, or one or more RISC or CISC processors. The network apparatus 620 may include at least some of those components shown in FIG. 6 such as a processor 622, for example. The network apparatus 620 may further include one or more other components not pertinent to the proposed scheme of the present disclosure (e.g., internal power supply, display device and/or user interface device) , and, thus, such component (s) of the network apparatus 620 are neither shown in FIG. 6 nor described below in the interest of simplicity and brevity.
Note that in some implementations, the network apparatus 620 may also be implemented as another communication apparatus like the communication apparatus 610 (e.g., a peer communication apparatus communicating with the communication apparatus 610) to implement a sidelink communication or communication on an unlicensed band.
In one aspect, each of the processor 612 and the processor 622 may be implemented in the form of one or more single-core processors, one or more multi-core processors, or one or more CISC processors. That is, even though a singular term “aprocessor” is used herein to refer to the processor 612 and the processor 622, each of the processor 612 and the processor 622 may include multiple processors in some implementations and a single processor in other implementations in accordance with the present disclosure. In another aspect, each of the processor 612 and the processor 622 may be implemented in the form of hardware (and, optionally, firmware) with electronic components including, for example and without limitation, one or more transistors, one or more diodes, one or more capacitors, one or more resistors, one or more inductors, one or more memristors and/or one or more varactors that are configured and arranged to achieve specific purposes in accordance with the present disclosure. In other words, in at least some implementations, each of the processor 612 and the processor 622 is a special-purpose machine specifically designed, arranged and configured to perform specific tasks including autonomous reliability enhancements in a device (e.g., as represented by the communication apparatus 610) and a network (e.g., as represented by the network apparatus 620) in accordance with various implementations of the present disclosure.
In some implementations, the communication apparatus 610 may also include a transceiver 616 coupled to the processor 612 and capable of wirelessly transmitting and receiving data. In some implementations, the communication apparatus 610 may further include a memory 614 coupled to the processor 612 and capable of being accessed by the processor 612 and storing data therein. In some implementations, the network apparatus 620 may also include a transceiver 626 coupled to the processor 622 and capable of wirelessly transmitting and receiving data. In some implementations, the network apparatus 620 may have a plurality of physical antennas which associates with a plurality of antenna ports. In some implementations, the network apparatus 620 may further include a memory 624 coupled to processor 622 and capable of being accessed by the processor 622 and storing data therein. Accordingly, the communication apparatus 610 and the network apparatus 620 may wirelessly communicate with each other via the transceiver 616 and the transceiver 626, respectively. To aid better understanding, the following description of the operations, functionalities and capabilities of each of the communication apparatus 610 and the network apparatus 620 is provided in the context of a mobile communication environment in which the communication apparatus 610 is implemented in or as a communication apparatus or a UE and the network apparatus 620 is implemented in or as another UE, or a network node or a network device of a communication network.
In some implementations, the processor 612 of the communication apparatus 610 or the processor 622 of the network apparatus 620 may generate a first sequence and a second sequence, wherein the second sequence is a repetition of the first sequence in frequency domain. The processor 612 or the processor 622 may change a value of at least one element in at least one of the first sequence and the second sequence and transmit, via the transceiver 616 or the transceiver 626, a transmission signal comprising at least the first sequence and the second sequence.
In some implementations, the value may be changed by performing a phase adjustment on the element in at least one of the first sequence and the second sequence.
In some implementations, the changing of the value of at least one element in at least one of the first sequence and the second sequence may comprise applying a first phase adjustment sequence to the first sequence and applying a second phase adjustment sequence to the second sequence. The first phase adjustment sequence and the second phase adjustment sequence may be different.
In some implementations, the first sequence may correspond to a first repetition index and the second sequence may correspond to a second repetition index. In some implementations, the first phase adjustment sequence may be generated based on the first repetition index and the second phase adjustment sequence may be generated based on the second repetition index.
In some implementations, the first sequence may correspond to a first identity and the second sequence may correspond to a second identity. In some implementations, the first phase adjustment sequence may be generated based on the first identity and the second phase adjustment sequence may be generated based on the second identity.
In some implementations, at least one of the first phase adjustment sequence and the second phase adjustment sequence may be predefined, preconfigured or indicated as a sequence with an ideal auto-correlation, a sequence with an auto-correlation satisfying a specific requirement or a sequence optimized based on the first sequence in an event that the first sequence is the original sequence to be repeated.
In some implementations, the first phase adjustment sequence or the second phase adjustment sequence may comprise a plurality of complex numbers.
In some implementations, the changing of the value of at least one element in at least one of the first sequence and the second sequence may comprise applying a phase adjustment sequence to the first sequence and the second sequence.
In some implementations, a length of the phase adjustment sequence may be equal to a summation of a length of the first sequence, a length of the second sequence and a length of a gap between the first sequence and the second sequence.
In some implementations, the phase adjustment sequence may be predefined, preconfigured or indicated as a sequence with an ideal auto-correlation, a sequence with an auto-correlation satisfying a specific requirement or a sequence optimized based on the first sequence in an event that the first sequence is the original sequence to be repeated.
In some implementations, the phase adjustment sequence may comprise a plurality of complex numbers.
In some implementations, the processor 612 of the communication apparatus 610 or the processor 622 of the network apparatus 620 may generate a first sequence and a second sequence, wherein the first sequence and the second sequence respectively comprises a plurality of elements and wherein the second sequence is a repetition of the first sequence in frequency domain. The processor 612 or the processor 622 may change content of at least one element in at least one of the first sequence and the second sequence and transmit, via the transceiver 616 or the transceiver 626, a transmission signal comprising at least a first sequence and a second sequence.
In some implementations, the content of the at least one element may be changed by performing a scrambling operation on at least one of the first sequence and the second sequence.
In some implementations, the changing of the content of the at least one element in at least one of the first sequence and the second sequence may comprise applying a first scrambling sequence to the first sequence and applying a second scrambling sequence to the second sequence. The first scrambling sequence and the second scrambling sequence may be different.
In some implementations, the first sequence may correspond to a first repetition index and the second sequence may correspond to a second repetition index. In some implementations, the first scrambling sequence may be generated based on the first repetition index and the second scrambling sequence may be generated based on the second repetition index.
In some implementations, the first sequence may correspond to a first identity and the second sequence may correspond to a second identity. In some implementations, the first scrambling sequence may be generated based on the first identity and the second scrambling sequence may be generated based on the second identity.
In some implementations, at least one of the first scrambling sequence and the second scrambling sequence may be predefined, preconfigured or indicated as a pseudo-random sequence.
In some implementations, the first scrambling sequence or the second scrambling sequence may comprise a plurality of binary values.
In some implementations, the changing of the content of the at least one element in at least one of the first sequence and the second sequence may comprise applying a scrambling sequence to the first sequence and the second sequence.
In some implementations, a length of the scrambling sequence may be equal to a summation of a length of the first sequence, a length of the second sequence and a length of a gap between the first sequence and the second sequence.
In some implementations, the scrambling sequence may be predefined, preconfigured or indicated as a pseudo-random sequence.
In some implementations, the scrambling sequence may comprise a plurality of binary values.
Illustrative Processes
FIG. 7 illustrates an example process 700 in accordance with an implementation of the present disclosure. The process 700 may be an example implementation of above scenarios/schemes, whether partially or completely, with respect to PAPR reduction in accordance with an implementation of the present disclosure. The process 700 may represent an aspect of implementation of features of an apparatus, such as the communication apparatus 610 or the network apparatus 620. The process 700 may include one or more operations, actions, or functions as illustrated by one or more of blocks 710, 720 and 730. Although illustrated as discrete blocks, various blocks of the process 700 may be divided into additional blocks, combined into fewer blocks, or eliminated, depending on the desired implementation. Moreover, the blocks of the process 700 may be executed in the order shown in FIG. 7 or, alternatively, in a different order. The process 700 may be implemented by the communication apparatus 610 or the network apparatus 620 or any suitable UE or machine type devices. Solely for illustrative purposes and without limitation, the process 700 is described below in the context of an apparatus, such as the communication apparatus 610 or the network apparatus 620. The process 700 may begin at block 710.
At 710, the process 700 may involve a processor of the apparatus, such as the processor 612 of the communication apparatus 610 or the processor 622 of the network apparatus 620, generating a first sequence and a second sequence, wherein the second sequence is a repetition of the first sequence in frequency domain. The process 700 may proceed from 710 to 720.
At 720, the process 700 may involve the processor changing a value of at least one element in at least one of the first sequence and the second sequence. The process 700 may proceed from 720 to 730.
At 730, the process 700 may involve the processor transmitting a transmission signal comprising at least the first sequence and the second sequence.
In some implementations, the value may be changed by performing a phase adjustment on the element in at least one of the first sequence and the second sequence.
In some implementations, the changing of the value of at least one element in at least one of the first sequence and the second sequence may comprise applying a first phase adjustment sequence to the first sequence and applying a second phase adjustment sequence to the second sequence. The first phase adjustment sequence and the second phase adjustment sequence may be different.
In some implementations, the first sequence may correspond to a first repetition index and the second sequence may correspond to a second repetition index. In some implementations, the first phase adjustment sequence may be generated based on the first repetition index and the second phase adjustment sequence may be generated based on the second repetition index.
In some implementations, the first sequence may correspond to a first identity and the second sequence may correspond to a second identity. In some implementations, the first phase adjustment sequence may be generated based on the first identity and the second phase adjustment sequence may be generated based on the second identity.
In some implementations, at least one of the first phase adjustment sequence and the second phase adjustment sequence may be predefined, preconfigured or indicated as a sequence with an ideal auto-correlation, a sequence with an auto-correlation satisfying a specific requirement or a sequence optimized based on the first sequence in an event that the first sequence is the original sequence to be repeated.
In some implementations, the first phase adjustment sequence or the second phase adjustment sequence may comprise a plurality of complex numbers.
In some implementations, the changing of the value of at least one element in at least one of the first sequence and the second sequence may comprise applying a phase adjustment sequence to the first sequence and the second sequence.
In some implementations, a length of the phase adjustment sequence may be equal to a summation of a length of the first sequence, a length of the second sequence and a length of a gap between the first sequence and the second sequence.
In some implementations, the phase adjustment sequence may be predefined, preconfigured or indicated as a sequence with an ideal auto-correlation, a sequence with an auto-correlation satisfying a specific requirement or a sequence optimized based on the first sequence in an event that the first sequence is the original sequence to be repeated.
In some implementations, the phase adjustment sequence may comprise a plurality of complex numbers.
FIG. 8 depicting an example process 800 in accordance with an implementation of the present disclosure. The process 800 may be an example implementation of above scenarios/schemes, whether partially or completely, with respect to PAPR reduction in accordance with an implementation of the present disclosure. The process 800 may represent an aspect of implementation of features of an apparatus, such as the communication apparatus 610 or the network apparatus 620. The process 800 may include one or more operations, actions, or functions as illustrated by one or more of blocks 810, 820 and 830. Although illustrated as discrete blocks, various blocks of the process 800 may be divided into additional blocks, combined into fewer blocks, or eliminated, depending on the desired implementation. Moreover, the blocks of the process 800 may be executed in the order shown in FIG. 8 or, alternatively, in a different order. The process 800 may be implemented by the communication apparatus 610 or the network apparatus 620 or any suitable UE or machine type devices. Solely for illustrative purposes and without limitation, the process 800 is described below in the context of an apparatus, such as the communication apparatus 610 or the network apparatus 620. The process 800 may begin at block 810.
At 810, the process 800 may involve a processor of the apparatus, such as the processor 612 of the communication apparatus 610 or the processor 622 of the network apparatus 620, generating a first sequence and a second sequence, wherein the second sequence is a repetition of the first sequence in frequency domain. The process 800 may proceed from 810 to 820.
At 820, the process 800 may involve the processor changing content of at least one element in at least one of the first sequence and the second sequence. The process 800 may proceed from 820 to 830.
At 830, the process 800 may involve the processor transmitting a transmission signal comprising at least the first sequence and the second sequence.
In some implementations, the content of the at least one element may be changed by performing a scrambling operation on at least one of the first sequence and the second sequence.
In some implementations, the changing of the content of the at least one element in at least one of the first sequence and the second sequence may comprise applying a first scrambling sequence to the first sequence and applying a second scrambling sequence to the second sequence. The first scrambling sequence and the second scrambling sequence may be different.
In some implementations, the first sequence may correspond to a first repetition index and the second sequence may correspond to a second repetition index. In some implementations, the first scrambling sequence may be generated based on the first repetition index and the second scrambling sequence may be generated based on the second repetition index.
In some implementations, the first sequence may correspond to a first identity and the second sequence may correspond to a second identity. In some implementations, the first scrambling sequence may be generated based on the first identity and the second scrambling sequence may be generated based on the second identity.
In some implementations, at least one of the first scrambling sequence and the second scrambling sequence may be predefined, preconfigured or indicated as a pseudo-random sequence.
In some implementations, the first scrambling sequence or the second scrambling sequence may comprise a plurality of binary values.
In some implementations, the changing of the content of the at least one element in at least one of the first sequence and the second sequence may comprise applying a scrambling sequence to the first sequence and the second sequence.
In some implementations, a length of the scrambling sequence may be equal to a summation of a length of the first sequence, a length of the second sequence and a length of a gap between the first sequence and the second sequence.
In some implementations, the scrambling sequence may be predefined, preconfigured or indicated as a pseudo-random sequence.
In some implementations, the scrambling sequence may comprise a plurality of binary values.
Additional Notes
The herein-described subject matter sometimes illustrates different components contained within, or connected with, different other components. It is to be understood that such depicted architectures are merely examples, and that in fact many other architectures can be implemented which achieve the same functionality. In a conceptual sense, any arrangement of components to achieve the same functionality is effectively "associated" such that the desired functionality is achieved. Hence, any two components herein combined to achieve a particular functionality can be seen as "associated with" each other such that the desired functionality is achieved, irrespective of architectures or intermedial components. Likewise, any two components so associated can also be viewed as being "operably connected" , or "operably coupled" , to each other to achieve the desired functionality, and any two components capable of being so associated can also be viewed as being "operably couplable" , to each other to achieve the desired functionality. Specific examples of operably couplable include but are not limited to physically mateable and/or physically interacting components and/or wirelessly interactable and/or wirelessly interacting components and/or logically interacting and/or logically interactable components.
Further, with respect to the use of substantially any plural and/or singular terms herein, those having skill in the art can translate from the plural to the singular and/or from the singular to the plural as is appropriate to the context and/or application. The various singular/plural permutations may be expressly set forth herein for sake of clarity.
Moreover, it will be understood by those skilled in the art that, in general, terms used herein, and especially in the appended claims, e.g., bodies of the appended claims, are generally intended as “open” terms, e.g., the term “including” should be interpreted as “including but not limited to, ” the term “having” should be interpreted as “having at least, ” the term “includes” should be interpreted as “includes but is not limited to,” etc. It will be further understood by those within the art that if a specific number of an introduced claim recitation is intended, such an intent will be explicitly recited in the claim, and in the absence of such recitation no such intent is present. For example, as an aid to understanding, the following appended claims may contain usage of the introductory phrases "at least one" and "one or more" to introduce claim recitations. However, the use of such phrases should not be construed to imply that the introduction of a claim recitation by the indefinite articles "a" or "an" limits any particular claim containing such introduced claim recitation to implementations containing only one such recitation, even when the same claim includes the introductory phrases "one or more" or "at least one" and indefinite articles such as "a" or "an, " e.g., “a” and/or “an” should be interpreted to mean “at least one” or “one or more; ” the same holds true for the use of definite articles used to introduce claim recitations. In addition, even if a specific number of an introduced claim recitation is explicitly recited, those skilled in the art will recognize that such recitation should be interpreted to mean at least the recited number, e.g., the bare recitation of "two recitations, " without other modifiers, means at least two recitations, or two or more recitations. Furthermore, in those instances where a convention analogous to “at least one of A, B, and C, etc. ” is used, in general such a construction is intended in the sense one having skill in the art would understand the convention, e.g., “asystem having at least one of A, B, and C” would include but not be limited to systems that have A alone, B alone, C alone, A and B together, A and C together, B and C together, and/or A, B, and C together, etc. In those instances where a convention analogous to “at least one of A, B, or C, etc. ” is used, in general such a construction is intended in the sense one having skill in the art would understand the convention, e.g., “asystem having at least one of A, B, or C” would include but not be limited to systems that have A alone, B alone, C alone, A and B together, A and C together, B and C together, and/or A, B, and C together, etc. It will be further understood by those within the art that virtually any disjunctive word and/or phrase presenting two or more alternative terms, whether in the description, claims, or drawings, should be understood to contemplate the possibilities of including one of the terms, either of the terms, or both terms. For example, the phrase “A or B” will be understood to include the possibilities of “A” or “B” or “A and B. ”
From the foregoing, it will be appreciated that various implementations of the present disclosure have been described herein for purposes of illustration, and that various modifications may be made without departing from the scope and spirit of the present disclosure. Accordingly, the various implementations disclosed herein are not intended to be limiting, with the true scope and spirit being indicated by the following claims.

Claims

A method, comprising:

generating, by a processor of an apparatus, a first sequence and a second sequence, wherein the second sequence is a repetition of the first sequence in frequency domain;

changing, by the processor, a value of at least one element in at least one of the first sequence and the second sequence; and

transmitting, by the processor, a transmission signal comprising at least the first sequence and the second sequence.
The method of Claim 1, wherein the value is changed by performing a phase adjustment on the element in at least one of the first sequence and the second sequence.
The method of Claim 1, wherein the changing of the value of at least one element in at least one of the first sequence and the second sequence further comprises:

applying a first phase adjustment sequence to the first sequence; and

applying a second phase adjustment sequence to the second sequence,

wherein the first phase adjustment sequence and the second phase adjustment sequence are different.
The method of Claim 3, wherein the first sequence corresponds to a first repetition index or a first identity, the second sequence corresponds to a second repetition index or a second identity, and wherein the first phase adjustment sequence is generated based on the first repetition index or the first identity and the second phase adjustment sequence is generated based on the second repetition index or the second identity.
The method of Claim 3, wherein at least one of the first phase adjustment sequence and the second phase adjustment sequence is predefined, preconfigured or indicated as a sequence with an ideal auto-correlation, a sequence with an auto-correlation satisfying a specific requirement or a sequence optimized based on the first sequence in an event that the first sequence is the original sequence to be repeated.
The method of Claim 3, wherein the first phase adjustment sequence or the second phase adjustment sequence comprises a plurality of complex numbers.
The method of Claim 1, wherein the changing of the value of at least one element in at least one of the first sequence and the second sequence further comprises:

applying a phase adjustment sequence to the first sequence and the second sequence.
The method of Claim 7, wherein a length of the phase adjustment sequence is equal to a summation of a length of the first sequence, a length of the second sequence and a length of a gap between the first sequence and the second sequence.
The method of Claim 7, wherein the phase adjustment sequence is predefined, preconfigured or indicated as a sequence with an ideal auto-correlation, a sequence with an auto-correlation satisfying a specific requirement or a sequence optimized based on the first sequence in an event that the first sequence is the original sequence to be repeated.
The method of Claim 7, wherein the phase adjustment sequence comprises a plurality of complex numbers.
A method, comprising:

generating, by a processor of an apparatus, a first sequence and a second sequence, wherein the second sequence is a repetition of the first sequence in frequency domain;

changing, by the processor, content of at least one element in at least one of the first sequence and the second sequence; and

transmitting, by the processor, a transmission signal comprising at least the first sequence and the second sequence.
The method of Claim 11, wherein the content of the at least one element is changed by performing a scrambling operation on at least one of the first sequence and the second sequence.
The method of Claim 11, wherein the changing of the content of the at least one element in at least one of the first sequence and the second sequence further comprises:

applying a first scrambling sequence to the first sequence; and

applying a second scrambling sequence to the second sequence,

wherein the first scrambling sequence and the second scrambling sequence are different.
The method of Claim 13, wherein the first sequence corresponds to a first repetition index or a first identity, the second sequence corresponds to a second repetition index or a second identity, and wherein the first scrambling sequence is generated based on the first repetition index or the first identity and the second scrambling sequence is generated based on the second repetition index or the second identity.
The method of Claim 13, wherein at least one of the first scrambling sequence and the second scrambling sequence is predefined, preconfigured or indicated as a pseudo-random sequence.
The method of Claim 13, wherein the first scrambling sequence or the second scrambling sequence comprises a plurality of binary values.
The method of Claim 11, wherein the changing of the content of the at least one element in at least one of the first sequence and the second sequence further comprises:

applying a scrambling sequence to the first sequence and the second sequence.
The method of Claim 17, wherein a length of the scrambling sequence is equal to a summation of a length of the first sequence, a length of the second sequence and a length of a gap between the first sequence and the second sequence.
The method of Claim 17, wherein the scrambling sequence is predefined, preconfigured or indicated as a pseudo-random sequence.
The method of Claim 17, wherein the scrambling sequence comprises a plurality of binary values.