CN114450902A

CN114450902A - First communication device for DFT-precoded OFDM with orthogonal spreading sequences

Info

Publication number: CN114450902A
Application number: CN201980100906.1A
Authority: CN
Inventors: 富兰崛克·伯根
Original assignee: Huawei Technologies Co Ltd
Current assignee: Huawei Technologies Co Ltd
Priority date: 2019-10-02
Filing date: 2019-10-02
Publication date: 2022-05-06
Also published as: WO2021063494A1

Abstract

The present disclosure relates to a first communication device for DFT-precoded OFDM with orthogonal spreading sequences. The first communication device (100) acquires M modulation symbols and one or more spreading sequences, wherein each spreading sequence has a length of N_SF. Obtaining M.N according to the M modulation symbols_SFAn element, wherein, the M.N_SFThe elements are arranged in M blocks, each block comprising N_SFAnd (4) each element. Obtaining a Discrete Fourier Transform (DFT) precoder input (122), wherein the DFT precoder input (122) is obtained by multiplying each element in each block with an element in the one or more spreading sequences, such that at least two elements in the one or more spreading sequences are different in at least one block. Finally, the process is carried out in a batch,providing the DFT precoder input (122) to a DFT precoder (130). Thus, the spreading factor N can be increased_SFWhile maintaining low power dynamics of the transmitted signal. Furthermore, the disclosure also relates to a corresponding second communication device, a corresponding method and a computer program.

Description

First communication device for DFT-precoded OFDM with orthogonal spreading sequences

Technical Field

The present application relates to a first communication device for DFT-precoded OFDM with orthogonal spreading sequences. Furthermore, the application also relates to a corresponding second communication device, a corresponding method and a computer program.

Abbreviation and vocabulary definitions

At least the following abbreviations and vocabularies are used in this disclosure:

3GPP third Generation partnership project (third Generation partnership project)

B-IFDMA Block IFDMA (block IFDMA)

CM cubic metric (cubic metric)

DFT discrete Fourier transform (discrete Fourier transform)

LTE Long term evolution (Long term evolution)

FDM frequency division multiplexing (frequency division multiplexing)

gNB NR node B (NR NodeB)

IDFT inverse DFT (inverse DFT)

IFDMA interweaved FDM access (interleaved FDM access)

NR New hollow (new radio)

Channel bandwidth occupied by OCB (occupied channel bandwidth)

OCC orthogonal cover code (orthogonalal cover code)

OFDM orthogonal FDM (orthogonal FDM)

PAPR Peak-to-average-Power ratio (peak-to-average-power ratio)

PRB physical resource block (physical resource block)

PSD power spectral density (power spectral density)

PUCCH physical uplink control channel (physical uplink control channel)

RRC radio resource control (radio resource control)

UE user equipment (user equipment).

(symbol)

In the present disclosure, at least the following notation is used:

number of M modulation symbols

N_PRBNumber of PRBs

Number of subcarriers per PRB

N_SFSpreading factor

w spreading sequence

v composite spreading sequences

v signal voltage

DFT output symbol

d_kModulation symbol

The DFT inputs the symbols.

Background

Transmissions in the unlicensed spectrum may be constrained by minimum Occupied Channel Bandwidth (OCB) requirements and additionally by maximum Power Spectral Density (PSD) requirements. Therefore, it is advantageous to transmit over a large bandwidth in order to occupy sufficient bandwidth and allow maximum transmit power. Considering Orthogonal Frequency Division Multiplexing (OFDM) transmission, one method is to generate a Block Interleaved Frequency Division Multiple Access (B-IFDMA) waveform using every nth Physical Resource Block (PRB) known in the literature. The concept of interlace (interlace) is sometimes used to indicate allocation of every nth PRB. A PRB is composed of a plurality of (e.g., 12) consecutive subcarriers.

For stand-alone unlicensed operation, i.e., when operating without licensed carrier assistance, a Physical Uplink Control Channel (PUCCH) needs to be transmitted in the unlicensed spectrum. The 3GPP New air interface (NR) release 15 supports several PUCCH formats, each having its own characteristics, but is not suitable for PRB interleaved transmission. One possibility is to enhance the NR

PUCCH formats

3 and 4 to PRB interleaved transmission, since these formats enable large payload and User Equipment (UE) multiplexing, respectively.

NR PUCCH format 3 is transmitted on 1 to 16 consecutive PRBs according to a payload, does not support UE multiplexing, and uses a Discrete Fourier Transform (DFT) precoder. The NR PUCCH format 4 is only within 1 PRB (i.e.,

sub-carriers), but supporting Orthogonal Cover Codes (OCCs) (i.e., Orthogonal spreading sequences) for multiplexing UEs prior to the DFT precoder. The purpose of the DFT precoder is to reduce the Power dynamics of the generated signal, usually measured by its Cubic Metric (CM) or Peak-to-Average Power Ratio (PAPR). For PUCCH format 4, spreading factor N is supported_SF1,2 and 4, OCC consists of DFT sequences.

The key performance metric related to the power back-off required by the transmitter is CM, defined as:

where v is the normalized voltage of the signal and v is_refIs the normalized voltage of the reference signal, "rms" denotes root mean square. Therefore, CM is determined according to the overall distribution of the signal voltage. In the prior art, the literature contains many methods for reducing the PAPR of a multi-carrier signal, which is a measure that depends on the peak power of the signal, and not on the distribution of the signal power. Therefore, although its non-linear behavior causes a significant reduction in CM, the methods developed for PAPR reduction do not necessarily bring the same gain to CM, which is generally more common in practice. In particular, notTransmissions on adjacent PRBs tend to drastically reduce CM.

Consider a DFT precoded OFDM system that utilizes OCC before the DFT precoder. When N is present_SF> 1, set

Will be spread so that N is repeated_SFNext, the process is carried out. The DFT precoder output is mapped to the input of an Inverse DFT (IDFT), resulting in an OFDM signal.

When mapped to the input of the inverse IDFT, the repeated data symbols may cause the subcarriers of the signal after the IDFT to increase sharply even though the DFT precoder is applied, thereby causing a large variation in the power of the transmitted signal. The large power variations of the signal may mean that the transmitter has to apply a transmit power back-off, resulting in a smaller coverage of the signal.

Since the DFT output is mapped to non-contiguous PRBs at IDFT in case of PRB interleaved transmission, the resulting signal is no longer a single carrier waveform (this is the case for DFT-precoded OFDM over contiguous PRBs, e.g. NR PUCCH formats 3 and 4). Therefore, when applying non-contiguous PRB allocation, the conventional solutions cannot be guaranteed to produce low CM signals. The input mapping of the IDFT is controlled by the interleaving structure and does not change normally. However, the input mapping of the DFT precoder may be optimized with respect to the CM. Therefore, the input mapping of DFT and spreading sequences needs to be properly designed.

Furthermore, when using PRB staggered transmission, resource overhead is increased due to the staggering, e.g., if each interlace includes 10 PRBs, the transmission will use at least 10 PRBs regardless of the data load. To improve spectral efficiency, a larger N is envisaged_SFAnd (4) a factor. However, this will further increase the number of repeated data symbols and may increase the power dynamics of the signal. Therefore, it is also desirable to provide low CM for larger spreading factors.

The conventional technical solution of DFT spread PUCCH for interlace transmission is by using

Spread the NR PUCCH formats 3 and 4 by the DFT size of (a). The DFT output is mapped to the allocated interleaved PRBs at the IDFT input.

Another conventional solution is limited to enhancing N assuming mapping (1) and contiguous PRBs, i.e. no interleaved transmission_PRBPUCCH format 3 for OCC with low PAPR but not low CM.

Disclosure of Invention

It is an object of embodiments of the present disclosure to provide a solution that reduces or solves the disadvantages and problems of the conventional solutions.

The above and other objects are achieved by the subject matter of the independent claims. Further advantageous embodiments of the disclosure can be found in the dependent claims.

According to a first aspect of the present disclosure, the above and other objects are achieved by a first communication device for a wireless communication system, the first communication device being configured to:

obtaining M modulation symbols, wherein M is a positive integer;

acquiring one or more spreading sequences, wherein each spreading sequence has a length of N_SF，N_SFIs a positive integer;

obtaining M.N according to the M modulation symbols_SFAn element, wherein, the M.N_SFThe elements are arranged in M blocks, each block comprising N_SFAn element;

obtaining a Discrete Fourier Transform (DFT) precoder input, wherein the DFT precoder input is obtained by multiplying each element in each block with an element in the one or more spreading sequences, at least two elements in the one or more spreading sequences being different in at least one block;

providing the DFT precoder input to a DFT precoder.

An advantage of the first communication device according to the first aspect is that the spreading factor N may be increased_SFWhile maintaining low power dynamics of the transmitted signal.

Implementation manner of first communication device according to first aspectThere is at least one block, wherein the elements in the block are formed by dividing one element having a length of N_SFThe elements in the spreading sequence of (2) are multiplied by the same modulation symbol.

The advantage of this implementation is that PRB interleaved transmission has a low CM.

In an implementation form of the first communication device according to the first aspect, the first communication device is configured to:

at least one block is arranged to include less than M modulation symbols.

In an implementation manner of the first communication device according to the first aspect, the first communication device is configured to:

multiplying the elements in each block with different elements in the one or more spreading sequences.

In an implementation manner of the first communication device according to the first aspect, the one or more lengths are obtained as N_SFThe spreading sequence of (a) comprises:

obtaining a length of N_SFA single spreading sequence of (a); and the first communications device is further configured to:

associating each element in at least one block with the length N_SFBy one or more elements in a single spreading sequence.

In one implementation form of the first communication device according to the first aspect, the DFT precoder input is formed by M · N_SFThe elements are given, and the arrangement of the elements is as follows:

wherein,

representing elements in the ith spreading sequence

Representing the M modulation symbols.

obtaining m orthogonal spreading sequences, wherein each spreading sequence has a length of N_SF，1＜m≤M；

Correlating the m orthogonal spreading sequences to different blocks; and

each element in each block is multiplied by an element in its associated spreading sequence.

The advantage of this implementation is that different orthogonal sequences can be applied to different blocks, thereby reducing the use of complex spreading sequences consisting of elements with the same value, which results in similarity of CM for all spreading sequences.

In one implementation form of the first communication device according to the first aspect, the M orthogonal spreading sequences form a length M · N_SFThe composite spreading sequence of (a), the composite spreading sequence being arranged to have N_SFAnd orthogonal composite spreading sequences.

The advantage of this implementation is that different users (e.g., UEs) are in M · N_SFOrthogonal multiplexing over a block of symbols.

In an implementation form of the first communication device according to the first aspect, the m orthogonal spreading sequences are determined by a predefined rule.

An advantage of this implementation is that no additional signaling may be provided to the second communication device in order to determine the composite spreading sequence.

In one implementation form of the first communication device according to the first aspect, the one or more spreading sequences are any one of a group comprising:

DFT sequence set;

a cyclically shifted Zadoff-Chu sequence set;

a Hadamard sequence set;

slepian sequence set; and

an orthogonal sequence set that does not include all sequences whose elements are the same.

The advantage of this implementation is that orthogonal multiplexing can be achieved while yielding low power dynamics of the transmitted signal.

mapping the DFT precoder output to an input of an Inverse Discrete Fourier Transform (IDFT);

acquiring a signal for transmission according to the output of the IDFT;

transmitting the signal to a second communication device.

The advantage of this implementation is a signal with low power dynamics.

In one implementation form of the first communication device according to the first aspect, mapping the DFT precoder output to an input of the IDFT comprises:

mapping the DFT precoder output to a set of non-contiguous resource blocks.

The advantage of this implementation is a signal with low power dynamics, while making it possible to use PRB interleaved transmission.

In one implementation form of the first communication device according to the first aspect, the first communication device is configured to provide an index of the one or more spreading sequences in at least one of:

radio resource control signaling;

an uplink control channel;

a downlink control channel;

media access control signaling; and

allocation of time-frequency resources for transmission of the signal.

The advantage of this implementation is that the second communication device (receiver) can unambiguously determine the spreading sequence used by the first communication device (transmitter).

In an implementation form of the first communication device according to the first aspect, the M modulation symbols are associated with any one of:

uplink control information;

downlink control information;

uplink data information; or

And downlink data information.

The advantage of this implementation is that signals with low power dynamics can be provided for any link direction (uplink/downlink) and any type of transmission information.

According to a second aspect of the present disclosure, the above and other objects are achieved by a second communication device for a wireless communication system, the second communication device being configured to:

receiving a signal from a first communication device;

obtaining M blocks according to the received signal, wherein M is a positive integer and M.N_SFThe elements are arranged in M blocks, each block including N_SFAn element; and

despreading the symbols in each block by multiplying each symbol with elements in the one or more spreading sequences, at least two elements in the one or more spreading sequences being different in at least one block, and adding despread symbols for the same modulation symbol; and

demodulating and decoding the summed despread symbols.

An advantage of the second communication device according to the second aspect is that spreading is performed in order to separate multiplexed data from different first communication devices.

According to a third aspect of the present disclosure, the above and other objects are achieved by a method for a first communication device, the method comprising:

obtaining M modulation symbols, wherein M is a positive integer;

obtaining a DFT precoder input, wherein the DFT precoder input is obtained by multiplying each element in each block with an element in the one or more spreading sequences, at least two elements in the one or more spreading sequences being different in at least one block; and

providing the DFT precoder input to a DFT precoder.

The method according to the third aspect may be extended to implementations corresponding to the implementations of the first communication device according to the first aspect. Thus, implementations of the method include features of corresponding implementations of the first communication device.

The advantages of the method according to the third aspect are the same as the advantages of the corresponding implementation of the first communication device according to the first aspect.

According to a fourth aspect of the present disclosure, the above and other objects are achieved by a method for a second communication device, the method comprising:

receiving a signal from a first communication device;

obtaining N blocks according to the received signal, wherein N is a positive integer, M.N_SFAn elementArranged in said N blocks, each block comprising N_SFAn element; and

demodulating and decoding the summed despread symbols.

The method according to the fourth aspect may be extended to implementations corresponding to the implementations of the second communication device according to the second aspect. Thus, implementations of the method include features of corresponding implementations of the second communication device.

The advantages of the method according to the fourth aspect are the same as the advantages of the corresponding implementation of the second communication device according to the second aspect.

The disclosure also relates to a computer program, wherein the program code, when executed by at least one processor, causes the at least one processor to perform any of the methods according to embodiments of the disclosure. Furthermore, the present disclosure also relates to a computer program product comprising a computer readable medium and the computer program, wherein the computer program is comprised in the computer readable medium and comprises one or more of the group of: ROM (read only memory), PROM (programmable ROM), EPROM (erasable PROM), flash memory, EEPROM (electrically EPROM), and hard disk drives.

Other applications and advantages of the embodiments of the present disclosure will be apparent from the following detailed description.

Drawings

The drawings are intended to illustrate and explain various embodiments of the present disclosure, in which:

fig. 1 shows a block diagram of an example of DFT-precoded OFDM with time-domain spreading sequences;

fig. 2 shows a block diagram of a first communication device provided by an embodiment of the present disclosure;

fig. 3 illustrates a first communication device implemented and/or integrated in a network access node provided by an embodiment of the present disclosure;

fig. 4 shows a flowchart of a method for a first communication device provided by an embodiment of the present disclosure;

fig. 5 shows a block diagram of a second communication device provided by an embodiment of the present disclosure;

FIG. 6 illustrates a receiving device implemented and/or integrated within a client device provided by embodiments of the present disclosure;

fig. 7 shows a flowchart of a method for a second communication device provided by an embodiment of the present disclosure;

fig. 8 illustrates a wireless communication system provided by an embodiment of the present disclosure;

FIG. 9 illustrates the absolute value of a window function of an embodiment of the present disclosure;

10a-10c illustrate cubic metric performance results of embodiments of the present disclosure;

FIG. 11 illustrates absolute values of window functions of an embodiment of the present disclosure;

12a-12c illustrate cubic metric performance results of embodiments of the present disclosure;

FIG. 13 illustrates the absolute value of a window function of an embodiment of the present disclosure;

14a and 14b illustrate cubic metric performance results of embodiments of the present disclosure;

fig. 15 illustrates subcarrier mapping of DFT precoder output provided by an embodiment of the present disclosure.

Detailed Description

An example of a conventional solution for DFT-precoded OFDM with OCC will now be described with reference to fig. 1 to provide an understanding of some of the analysis behind concluding the embodiments of the present disclosure. In this respect, with reference to step I in FIG. 1, consider that

The number of the modulation symbols is one,

these symbols are arranged at the input of the DFT precoder (step II), in phase with the spreading sequence (i.e. OCC)The result of the multiplication is,

i.e. applying a spreading factor N_SFWherein N is_SFIs an integer, especially N_SFIs greater than 1. The modulation symbols may be taken from any well-known modulation format (e.g., pi/2-BPSK, QPSK, 16-QAM, etc.) and carry uplink control information bits that have been encoded by a polar code or reed-muller code, etc.

In NR PUCCH format 4, a 12-point DFT output is mapped to 1 PRB at an N-point Inverse DFT (IDFT) input in step III, the output thereof is processed from parallel to serial in step IV, and then a Cyclic Prefix (CP) is inserted in step V. The size N of the IDFT is related to the system bandwidth, each input element represents transmission on a subcarrier, and zeros are inserted on unassigned subcarriers.

As an enhancement of NR PUCCH formats 3 and 4, generation has been proposed

A modulation symbol of which N_PRBIs a number of interleaved PRBs, e.g., 10 PRBs. The spreading factor is limited to a value where M is an integer.

The input of the point DFT precoder may be denoted as M · N_SFElements arranged as:

wherein,

is the number of elements in (1), the ith OCC is

It is given. Sequence w⁽ⁱ⁾,i＝0,1,…,N_SF-1 comprises an orthogonal set. The length L may be further influencedThe implementation requirements of the DFT size are limited such that it must be a multiple of these factors, e.g., 2,3, and 5, etc.

Of DFT precoders

The output values are mapped to subcarriers in the interleaved PRBs at the IDFT input. Note that, according to (1), symbols are mapped to the positions of DFT precoder inputs as follows: each element in the spreading sequence

In N_SFRepeating at successive positions; each data symbol d_kIs mapped periodically to every mth location.

(1) Is further characterized in that the input of the DFT precoder is divided into N_SFM blocks of size, wherein each block comprises M different modulation symbols. For example, the first block is

First, when the input of the DFT precoder is given by (1), the output of the DFT precoder (which will be subsequently mapped to the input of the IDFT) is considered. After some algebras, use L ═ MN_SFObtained by the following method:

wherein n is 0,1, …, L-1, and

in (2), the first sum is independent of k, and thus may be based on the coefficient at the IDFT input

Considered as a window function. Then, use

Then

Therefore, using L ═ MN_SFObtaining:

from (3), two attributes can be observed, namely that the L-point DFT of (2) is reduced to the M-point DFT; the output of the DFT is assumed to be every Nth_SFNon-zero values for the subcarriers. The second attribute results in comb transmission, called Interleaved Frequency Division Multiple Access (IFDMA), due to the use of DFT sequences as OCC. It can be seen from (3) that different OCCs (i.e., index i) result in different comb transfers. As shown in (3), the implementation can also avoid using OCC, only compute M-point DFT and map its output to every Nth DFT_SFAnd (4) sub-carriers. Thus, due to the presence of N_SFOne transmission comb, i.e. using every N_SFSub-carriers, the multiplexing of the UE in the frequency domain, are orthogonal by FDM.

Fig. 2 is a block diagram of a first communication device 100 provided by an embodiment of the present disclosure. The first communication device 100 includes a first processing block 110, a second processing block 120, and a DFT precoder block 130.

The first processing block 110 is used to obtain Modulation Symbols (MS) and one or more Spreading Sequences (SS). In other words, the first communication device 100 is configured to obtain M modulation symbols, where M is a positive integer; for acquiring one or more spreading sequences, wherein each spreading sequence has a length of N_SF，N_SFIs a positive integer, especially N_SFIs greater than 1. The first processing block 110 outputs M modulation symbols and one or more spreading sequences to the second processing block 120.

The second processing block 120 is configured to receive the output 112 from the first processing block 110 and obtain M · N from the M modulation symbols_SFAn element of which M.N_SFThe elements are arranged in M blocks, each block comprising N_SFAnd (4) each element.

An element represents a symbol having a value, which may be a complex value. Examples of the element are an element in a spreading sequence, an element in a modulation symbol, or an element obtained by multiplying an element in a spreading sequence and a modulation symbol.

The second processing block 120 is further configured to obtain a DFT precoder input 122, wherein the DFT precoder input 122 is obtained by multiplying each element in each block with an element in one or more spreading sequences, at least two elements of the one or more spreading sequences being different in at least one block. The second processing block 120 provides a DFT precoder input 122 to an input of a DFT precoder 130.

The DFT precoder block 130 is used to obtain the DFT precoder input 122 and output a transformation of the time domain input to the frequency domain output.

In an embodiment of the present disclosure, the first communication device 100 further comprises a mapping block 140, the mapping block 140 being configured to obtain the DFT output 132 from the DFT precoder block 130 and to map the DFT precoder output 132 to an input of the IDFT block 150.

In an embodiment, mapping the DFT precoder output 132 to the input of the IDFT 150 comprises mapping the DFT precoder output 132 to a set of non-contiguous resource blocks. L ═ MN of DFT precoder_SFThe output symbols are mapped to N interleaved at the input of IDFT block 150_PRBA PRB.

Fig. 15 shows N from the DFT precoder block 130_PRBTwo non-limiting examples of mappings for 10 blocks, each of which will be

The symbols comprising N interleaved to the IDFT input_PRBA PRB. The mapping may be performed from top to bottom as shown in the left diagram in fig. 15. The mapping may also be performed from bottom to top as shown in the right diagram in fig. 15.

IDFT block 150 is used to retrieve mapping 142 from mapping block 140 and output a transform of the frequency domain input to the time domain output.

Finally, further processing is performed to obtain a Radio Frequency (RF) signal 510 for transmission based on the output of the IDFT 150. Non-limiting examples of such processing are parallel-to-serial mapping, CP insertion, transmit filtering, antenna processing (including mapping data to layers and antenna ports), and up-conversion to the RF domain. The first communication device 100 transmits a signal 510 to the second communication device 300 as shown in fig. 8.

In one possible embodiment, there is at least one block, wherein the elements in the block are formed by dividing a block of length N_SFThe elements in the spreading sequence of (2) are multiplied by the same modulation symbol. For example, a block may be represented as

Wherein the modulation symbol is d₀The spreading sequence is

In one possible embodiment, the first communication device 100 may be configured to arrange the at least one block to include less than M modulation symbols. For example, a block with 1 modulation symbol may be represented as

Thus comprising a modulation symbol d₀. Another example is a block with 2 modulation symbols, which can be represented as

In a further non-limiting example of a block having greater than 1 but less than M modulation symbols, consider N _SF4 and M3. The 3 blocks may be arranged as

And

alternatively, the 3 blocks may also be arranged as

And

other orderings of modulation symbols are possible, as long as the modulation symbols have been multiplied with each element in the spreading sequence, taking into account all blocks.

In one possible embodiment, the first communication device 100 may be configured to multiply the elements in each block with different elements in one or more spreading sequences. For example, if a block consists of 1 modulation symbol d₀Arranged, then all elements in the spreading sequence will be as

This applies to the blocks. Thus, each block can be processed separately in the second communication device (receiver), i.e. despreading can be performed per block.

Fig. 3 illustrates a first communication device 100, e.g., an Integrated Access and Backhaul (IAB) in a UE or NR, implemented and/or integrated in a network access node 600 provided by an embodiment of the present disclosure. It should be noted, however, that the first communication device 100 may also be implemented in a client device or any other suitable communication device having transmission capabilities in a communication system.

In the embodiment shown in fig. 3, network access node 600 comprises a processor 602, a transceiver 604, and a memory 606. The processor 602 is coupled to the transceiver 604 and the memory 606 through a communication component 608 as is known in the art. The network access node 600 may communicate wirelessly and wiredly in wireless and wireline communication systems, respectively. Wireless communication capability is provided through an antenna or antenna array 610 coupled to the transceiver 604, while wired communication capability is provided through a wired communication interface 612 coupled to the transceiver 604. In the present disclosure, the use of the network access node 600 for performing certain actions should be understood to mean that the network access node 600 includes suitable means, such as the processor 602 and the transceiver 604, for performing the actions. Further details regarding the network access node 600 can be found in later sections of this disclosure.

Fig. 4 shows a flow diagram of a corresponding method 200 that may be performed in a first communication device 100 (e.g., the first communication device 100 shown in fig. 2). The method 200 includes obtaining 202M modulation symbols, where M is a positive integer.

The method 200 further includes acquiring 204 one or more spreading sequences, wherein each spreading sequence has a length N_SF，N_SFIs a positive integer.

The method 200 further comprises obtaining 206M · N from the M modulation symbols_SFAn element, wherein, the M.N_SFThe elements are arranged in M blocks, each block comprising N_SFAnd (4) each element.

The method 200 further includes obtaining 208 a DFT precoder input, wherein the DFT precoder input is obtained by multiplying each element in each block with an element in the one or more spreading sequences, at least two elements in the one or more spreading sequences being different in at least one block.

The method 200 further includes providing 210 a DFT precoder input 122 to the DFT precoder 130.

It should be understood that the processes in FIG. 4 are non-limiting examples, and that each process may not depend on previous processes.

Fig. 5 shows a block diagram of a second communication device 300 provided by an embodiment of the present disclosure. The second communication device 300 includes a receiving block 310, a first processing block 320, a despreading frequency block 330, and a demodulation code block 340.

The receiving block 310 is used to receive an RF signal 510 from the first communication device 100, as shown in fig. 8. The receiving block 310 provides the baseband representation of the RF signal 510 to the first processing block 320.

The first processing block 320 obtains the signal 510 from the receiving block 310. The first processing block 320 may be used to acquire one or more spreading sequences SS, where each spreading sequence has a length N_SF，N_SFIs a positive integer.

The first processing block 320 may be configured to obtain M blocks from the received signal 510, where M is a positive integer and M · N_SFEach element is arranged in the M blocksIn, each block includes N_SFAnd (4) each element.

The receiver knows from the receiving side that each element in each block is the product of a modulation symbol multiplied by an element in one or more spreading sequences, at least two elements of which are different in at least one block. This information is used by the receiver (e.g., first processing block 320) for despreading, which is given below and not described in detail herein.

First processing block 320 may be used to output modulation symbols 322 to despreading frequency block 330.

Despreading block 330 may be used to obtain modulation symbols 322 from first processing block 320. Despreading block 330 is configured to despread the symbols in each block by multiplying each symbol by elements in the one or more spreading sequences, at least two elements in the one or more spreading sequences being different in at least one block, and adding despread symbols for the same modulation symbol.

The despreading operation is performed by modulating symbols by N received symbols including the modulating symbols_SFThe elements of a block are multiplied element by element with a spreading sequence and summed to form a sum. Despreading block 330 is used to output summed despread symbols 332 to demodulation decoding block 340.

Demodulation decoding block 340 may be used to obtain summed despread symbols 332 from despread frequency block 330. The demodulation decoding block 340 is for demodulating and decoding the summed despread symbols to provide an output as a set of information bits.

In general, the second communication device 300 may be used to process the signals 510 in an order that is opposite to the processing at the first communication device 100. The received RF signal 510 is subjected to baseband processing including, for example, sampling, filtering, a/D conversion, and the like. The baseband signal is further processed by removing the CP, performing DFT, performing channel equalization, performing IDFT, performing a despreading operation, performing channel decoding, and the like.

Alternatively, channel equalization may be performed after the IDFT. In more detail, according to an embodiment of the present disclosure, the second communication device 300 may perform the following main steps:

1. receiving an RF signal 510 from the first communication device 100;

2. converting received signal 510 from the RF domain into the baseband domain;

3. performing DFT on the baseband signal;

4. performing channel equalization on the output of the DFT;

5. extracting distributed time-frequency resources from the balanced output of DFT;

6. performing inverse DFT on the extracted time-frequency resources;

7. extracting an input block from an output of the inverse DFT;

8. obtaining at least one length of N_SFThe spreading sequence of (a);

9. despreading the modulation symbols in each input block; and

10. and demodulating and decoding the despread modulation symbols to obtain transmitted data information.

In this regard, in an embodiment of the present disclosure, the M modulation symbols are associated with any one of Uplink (UL) control information, Downlink (DL) control information, uplink data information, or downlink data information. Thus, the information content may relate to data for uplink or downlink or to control information for uplink or downlink. For data transmission, a Physical Uplink Shared Channel (PUSCH) and a Physical Downlink Shared Channel (PDSCH) may be used. As the control information, a Physical Uplink Control Channel (PUCCH) and a Physical Downlink Control Channel (PDCCH) may be used.

Fig. 6 illustrates a second communication device 300, such as an IAB in a next generation node B (gNB) or NR, implemented and/or integrated in a client device 700 provided by an embodiment of the present disclosure. It should be noted, however, that the second communication device 300 may also be implemented in any other suitable communication device having receiving capabilities in a communication system, for example, a UE in a device to device (D2D) scenario.

In the embodiment shown in fig. 6, the client device 700 includes a processor 702, a transceiver 704, and a memory 706. The processor 702 may be coupled to the transceiver 704 and the memory 706 by a communication component 708 as is known in the art.

The client device 700 also includes an antenna or antenna array 710 coupled to the transceiver 704, meaning that the client device 700 is used for wireless communication in a wireless communication system.

In this disclosure, the client device 700 may be used to perform certain actions may be understood to mean that the client device 700 includes suitable components, e.g., the processor 702 and the transceiver 704, for performing the described actions. More details about the client device 700 can be found in later sections of this disclosure.

Fig. 7 shows a flow diagram of a corresponding method 400 that may be performed in the second communication device 300 (e.g., shown in fig. 5).

The method 400 includes receiving 402 a signal 510 from a first communication device 100.

The method 400 further includes acquiring 404 one or more spreading sequences, wherein each spreading sequence has a length N_SF，N_SFIs a positive integer.

The method 400 further includes obtaining 406M blocks from the received signal 510, where M is a positive integer and M.N_SFThe elements are arranged in M blocks, each block including N_SFAnd (4) each element.

The receiver knows from the receiving side that each element in each block is the product of a modulation symbol multiplied by an element in one or more spreading sequences, at least two elements of which are different in at least one block. This information is used by the receiver (e.g., the second communication device 300) for despreading, which is given below and not described in detail here.

The method 400 further includes despreading 408 the symbols in each block by multiplying each symbol by an element in one or more spreading sequences, at least two elements of the one or more spreading sequences being different in at least one block, and adding despread symbols corresponding to the same modulation symbol.

The method 400 further includes demodulating 410 the summed despread symbols.

It should be understood that the processes in fig. 7 are non-limiting examples, and each process may not depend on the previous process, and the order of the processes is non-limiting.

Fig. 8 illustrates a wireless communication system 500 provided by an embodiment of the disclosure. The wireless communication system 500 includes a first communication device 100 and a second communication device 300.

As shown in fig. 8 and previously mentioned, the first communication device 100 may be part of a network access node 600, e.g., a gNB; the second communication device 300 may be part of a client device 700, e.g. a UE. However, the opposite case is also within the scope of the present disclosure, i.e. the first communication device 100 is part of a client device and the second communication device 300 is part of a network access node.

For simplicity, the wireless communication system 500 shown in fig. 8 includes only one first communication device 100 and one second communication device 300. However, the wireless communication system 500 may include any number of first communication devices 100 and any number of second communication devices 300 without departing from the scope of the present disclosure.

In the wireless communication system 500, the network access node 600 transmits RF signals 510 in the DL to the client device 700, and the client device 700 receives the RF signals 510 and processes the RF signals 510 accordingly. The client device 700 transmits RF signals in the uplink to the network access node 600. The wireless communication system 500 may be implemented with any Orthogonal Frequency Division Multiplexing (OFDM) system using DFT precoding. Furthermore, embodiments of the present disclosure are not limited to unlicensed spectrum, but are applicable to higher spectrum, for example, where waveforms with low power dynamics are desired.

In embodiments of the present disclosure, different aspects of spreading sequence index signaling are also disclosed. The signaling of spreading sequence indices may be performed by any combination of: radio resource control signaling, uplink control channel, downlink control channel, Medium Access Control (MAC) Control Element (CE), and allocation of time-frequency resources for transmission of signal 510.

For example, the spreading sequence index may be provided to the second communication device 300 by higher layer signaling (e.g., in Radio Resource Control (RRC)). The spreading sequence index may be predefined by a standard specification. For example, the standard specification may define a set of spreading sequences in a table, each sequence having an index.

In another example, if a composite spreading sequence is to be arranged, it constitutes a spreading sequence index (i.e., index i ═ 0,1, …, N)_SF-1) can be obtained by predefined rules in the index signaled.

In yet another example, the spreading sequence index may be implicitly determined from the transmission parameters. For example, the parameters may include interlace index or relate to allocated time-frequency resources.

The signaling of the spreading sequence index may be performed in an uplink control channel and/or a downlink control channel of the wireless communication system 500.

Other embodiments of the disclosure are described below.

According to an embodiment of the present disclosure, using the input of a DFT precoder as M.N is disclosed_SFElements arranged as:

in mapping (4), the spreading sequence is repeated block by block. (4) Another feature different from (1) is that the input of the DFT precoder is divided into M bits of size N_SFWherein each block comprises 1 modulation symbol. For example, the first block is

The output of the DFT precoder may be obtained after some algebra:

(5) is different because the denominator in the exponential function is L instead of N in (2)_SF. The second sum represents the M-point DFT of the data symbol, instead of the L-point DFT in (2), i.e.

When N is present_SFWhen 1, the values (3) and (5) are equal.

In addition, if the DFT of the spreading sequence is defined,

it follows that the inner products of the spreading sequences in the frequency domain (i.e., after the DFT precoder) are orthogonal, i.e.,

wherein,

represents the complex conjugate of w. Thus, the DFT outputs from two users transmitting different sets of modulation symbols and using different spreading sequences will be orthogonal.

In the DFT-mapped embodiment disclosed above, M modulation symbols are transmitted using 1 spreading sequence (i.e., index i). The length of the spreading sequence being N_SFAnd by expanding to a length of N by repetition in the mapping step (1) or (4)_SFAnd M. That is, one spreading sequence index i is used to align L ═ N in (4)_SFA block of M symbols. Thus, the use of a length of N has been described_SFAnd each element in at least one block is associated with a length N_SFOf a singleOne or more elements in the spreading sequence are multiplied.

However, in other embodiments of the present disclosure, more than 1 is used (c:)>1) Transmitting N spreading sequences, but not more than M spreading sequences_SFM modulation symbols. In this regard, the first communication device 100 acquires m orthogonal spreading sequences, where each spreading sequence has a length of N_SFWherein M is an integer satisfying the relationship 1 < m.ltoreq.M. The first communication device 100 associates the m orthogonal spreading sequences into different blocks and multiplies each element in each block by an element in its associated spreading sequence. In an embodiment, the M orthogonal spreading sequences form a length of M · N_SFThe composite spreading sequence of (a), the composite spreading sequence being arranged to have N in total_SFAnd orthogonal composite spreading sequences. A basic example of a composite spreading sequence with M-1 is a sequence with M repetitions of length N_SFDefined by the spreading sequence of (a), e.g.,

thus, such a structure allows defining a length of M.N_SFN of (A)_SFA set of orthogonal composite spreading sequences. By appropriate selection of the orthogonal sequences that are formed, this structure can also be defined to have a length of M.N_SFN of (A)_SFA set of orthogonal composite spreading sequences.

For m > 1, the composite spreading sequence will consist of m different spreading sequences, i.e.

Wherein i ≠ j.

In an embodiment, the m orthogonal spreading sequences are determined by a predefined rule. This means that the OCC index used for the composite spreading sequence can be determined without any additional signalling above the OCC index used for transmission of the single OCC index i. For example, OCC index j may be a function of OCC index i, and so on.

Any of the DFT input mappings (1) or (4) described above may be used with the above structure using m > 1 composite spreading sequences that make up the spreading sequence. The benefit of using more than one spreading sequence per block of M modulation symbols is that, for example, the use of all-1 spreading sequences, which are spreading sequences that produce a fairly high CM, can be prevented.

As one non-limiting example, consider the DFT input mapping and N in equation (1)_SF2 and the following mapping, where M may be N_SFInteger division and maintained by alternating spreading sequence indices

And

orthogonality therebetween

And

for both examples, the composite spreading sequence will become:

and

another non-limiting example is consider (4) to:

and

for both examples, the composite spreading sequence will become:

and

in these examples, each data symbol is multiplied by the same spreading sequence. Thus, for any of the examples above, if w⁽⁰⁾＝[1,1]And w⁽¹⁾＝[1,-1]，

And

none of them use all of the composite spreading sequences.

There are several ways how to apply multiple spreading sequences to a block of M modulation symbols. The requirement is that M of the length N_SFIs composed of spreading sequences of length MN_SFComposite spreading sequence of (2)

Should still be orthogonal.

For example, modulation symbol d for spread information_kK-0, 1, …, M-1, a simple predefined rule is to use the spreading sequence i (i + k) mod N_SFWherein i is 0,1, …, N_SF-1, "mod" is the modulo operator. Since 0. ltoreq. i, j. ltoreq. N_SF-1, then (i + k) mod N_SF≠(j+k)mod N_SFWhen i ≠ j, the composite spreading sequences corresponding to i and j are orthogonal.

Orthogonal sequence set

As will be understood from the present disclosure, CM is determined from the spreading sequence by its DFT (i.e., its window function). In embodiments of the present disclosure, different sets of orthogonal sequences may be used to spread the modulation symbols, and thus several non-limiting examples of such orthogonal sequences are considered and described in this section.

DFT sequence

In an embodiment, a DFT sequence is used to spread the modulation symbols. Sequence is composed of

Defining:

since (6) is not constant and is determined from the index n, it acts as a frequency domain filter, i.e., a value, at the IDFT input

The window function of (2). The absolute value of function (6) is plotted in FIG. 9, N _SF4, M-30 and i-0, 1,2, 3. It should be noted from (6) that using (4) of the DFT sequence does not result in comb transmission, i.e., all L subcarriers are allocated at the output of the DFT precoder, compared to (1) of the DFT sequence. However, after the DFT precoder, the multiplexing is still orthogonal, as shown above in the derivation of the inner product of the spreading sequences in the frequency domain.

In FIGS. 10a-10c, N is used according to (1) and (4)_SFFor each spreading sequence, i is 0,1, …, N, 4, 6 and 8_SF-1 plots CM to DFT mappings. Also included is the reference case, i.e. no spread spectrum N _SF1. FIGS. 10a-10c illustrate the use of DFT sequencesThe columns compare CM of a transmission signal input mapped to DFT, whose spreading factor N is a spreading factor, according to formula (1) and formula (1)_SFIn fig. 10a equal to 4, in fig. 10b equal to 6, in fig. 10c equal to 8.

As can be seen from fig. 10a-10c, the DFT mapping according to (4) may provide a lower CM than defined by (1), which is even lower than the reference case without spreading sequences. However, it can also be seen that (4) has a spreading sequence with a rather high CM, which is a spreading sequence corresponding to i ═ 0, i.e., sequences that are all 1. In conventional NR systems, the spreading sequence index is indicated to the UE, so that the use of this particular sequence can be avoided, or even removed from the set of spreading sequences. Another option is to explore other types of spreading sequences that do not contain all 1's.

Zadoff-Chu sequences

In an embodiment, N is formed by cyclically shifting a Zadoff-Chu (ZC) sequence_SFA set of orthogonal sequences. Thus, the spreading sequence will be defined by the following equation:

wherein u is more than 0 and less than N_SFIs and N_SFThe root indices of the primes, i.e., their greatest common divisor, are 1, and "mod" is the modulus operator. These spreading sequences can be shown to be orthogonal. The window function becomes

It is a quadratic sum in p, with closed solutions only in certain special cases. The absolute value of function (7) is plotted in FIG. 11, N _SF4, M-30 and i-0, 1,2, 3.

In FIGS. 12a-12c, N is used according to (4)_SF4, 6 and 8 (using root index u-3, 5 and 3 respectively) for each spreading sequence i-0, 1, …, N_SF-1 plot CM and DFT-mapping. Also included is the reference case, i.e. no spread spectrum N _SF1. Fig. 12a to 12c show CM contrasts of a transmission signal in which an input is mapped to DFT according to formula (4) using a DFT sequence having a spreading factor equal to 4 in fig. 12a, equal to 6 in fig. 12b, and equal to 8 in fig. 12 c.

As can be seen from fig. 12a-12c, ZC sequences do not produce a specific high CM spreading sequence (because there is no ZC sequence consisting of one value), as is the case with DFT sequences.

Hadamard sequence

In an embodiment, a Hadamard sequence is used to spread the modulation symbols. If N is present_SFEqual to 2 or equal to a multiple of 4, the spreading sequence can be determined from the rows or columns of the Hadamard matrix. The advantage of Hadamard sequences is that they are real-valued, i.e., +1 or-1, and therefore low complexity implementations are possible because the spreading operation can be performed by direct phase shifting rather than by complex-valued multiplication.

In FIG. 13, for N_SFHadamard sequence rendering of 4, M30,

i

0,1,2,3

Absolute value of (a).

In FIGS. 14a-14b, N is used according to (4)_SFEach spreading sequence i of 4 and 8 for DFT sequence and Hadamard sequence, respectively, is 0,1, …, N_SF-1 plots CM and DFT mappings. Also included is the reference case, i.e. no spread spectrum N _SF1. FIGS. 14a-14b illustrate CM contrast for a transmit signal mapping an input to DFT equation (4) using the use of a DFT sequence with a spreading factor N_SFEqual to 4 in fig. 14a and equal to 8 in fig. 14 b.

As can be seen in fig. 14a-14b, the Hadamard sequence performs better than the DFT sequence.

Orthogonal sequences not including sequences in which all elements are identical

In an embodiment, a set of orthogonal sequences that do not include sequences with all elements being the same are used to spread the modulation symbols. A problem with spreading sequences consisting of only a number of "1" s is the potential in-phase of the modulation symbols, which may increase CM. However, the method is not limited to the specific methodThe phase shift of the signal by CM is invariant, and therefore consists of only-1 or any other complex-valued constant (i.e., a spreading sequence with all elements having the same value Q,

) The constituent spreading sequences will also result in high CM. Therefore, a set of spreading sequences that does not include such sequences is useful.

In one example, a first set of spreading sequences is defined as comprising

The sequence of (a). The set of DFT sequences is such a candidate set. The set of spreading sequences may be represented by N_SF×N_SFThe matrix a represents the matrix whose rows (or columns) are composed of spreading sequences. Then, from linear algebra, it can be known that the change of the base to the new orthogonal base, i.e. the second set of spreading sequences, can obtain a new set of spreading sequences by projecting the matrix P, B ═ AP. By appropriately selecting P (which may be an orthogonal matrix, for example), the second set of spreading sequences may not include

The sequence of (a).

Slepian sequence

In an embodiment, Slepian sequences are used to spread the modulation symbols. Slepian sequences are also called Discrete Prolate Spheroid Sequences (DPSS). The property of these sequences is that the discrete-time fourier transform of the sequence has the greatest concentration of signal energy within a given finite frequency band, i.e., the energy of the sidelobes outside the frequency band is minimized.

DPSS may be used as a window sequence following the DFT precoder, which is known to reduce PAPR of the transmitted signal. In this case, there is a window function, and only one DPSS is applied.

Instead, here we disclose generating multiple DPSSs and using them as spreading sequences, while also achieving the goal as a window function. Slepian sequences are obtained by solving the problem of eigenvalues, and Slepian sequences of the nth orderCorresponding to the (n +1) th eigenvalue. It can be shown that Slepian sequences of the nth order are orthogonal to Slepian sequences of lower order. Thus, it is disclosed herein that 1 to N can be used_SFThe set of Slepian sequences of order form a set of spreading sequences.

In general, an inverse DFT of a windowed sequence will produce a time-domain spread spectrum sequence that, if the windowed sequence is orthogonal, is also orthogonal. However, since the window sequence has a length of L, the spreading sequence has a length of N_SFIt is therefore not possible to perform an inverse DFT of a window sequence of length L, since a length N is not given_SFThe OCC of (1).

Thus, here, generating a length of N is disclosed_SFAnd then performing N of these sequences_SFPoint IDFT to obtain a spreading sequence. Since it is shown above that the window function is an L-point DFT of the spreading sequence, the corresponding length N_SFAfter the L-point DFT precoder, the window function of the Slepian sequence becomes the original length N_SFL/N of Slepian sequence of (1)_SFA double oversampled version.

Thus, in one example, a spreading sequence is defined as

Wherein,

and

is the ith Slepian sequence, i.e., the Slepian sequence is defined in the frequency domain and the spreading sequence is obtained as its inverse DFT.

In another example of the above-described method,

wherein,

is the ith Slepian sequence, i.e., the Slepian sequence is defined in the time domain and represents a spreading sequence.

In the above description, the normalization factor, for example, M, L, N_SFInserted already before the DFT or IDFT operation or as part of the sequence definition. It should be understood that CM is invariant to these normalization factors, primarily for symbolic convenience.

The network access node 600 in the present disclosure includes, but is not limited to: NodeB in a Wideband Code Division Multiple Access (WCDMA) system, evolved Node B (eNB) or evolved NodeB (eNodeB) in an LTE system, or a relay Node or access point in a fifth generation (5G) network, or a vehicle-mounted device, a wearable device, or a gNB.

Further, the network access node 600 herein may also be denoted as a wireless network access node, an access point, or a Base Station (e.g., a Radio Base Station (RBS)), which in some networks may be referred to as a transmitter, "gNB", "gdnodeb", "eNB", "eNodeB", "NodeB", or "B node", depending on the technology and terminology used.

Depending on the transmission power and thus also the cell size, the radio network access nodes may be of different classes, e.g. macro eNodeB, home eNodeB or pico base station. A wireless network access node may be a Station (STA), which is any device that includes an IEEE 802.11 compliant MAC and PHY interface to the wireless medium. The radio network access node may also be a base station corresponding to a 5G radio system or higher than a 5G radio system.

The processor of network access node 600 may be referred to as one or more general purpose CPUs, one or more DSPs, one or more ASICs, one or more FPGAs, one or more programmable logic devices, one or more discrete gates, one or more transistor logic devices, one or more discrete hardware components, and one or more chipsets.

The memory of the network access node 600 may be read-only memory, random access memory, or NVRAM.

The transceiver of the network access node 600 may be a transceiver circuit, a power controller, an antenna, or an interface to communicate with other modules or devices. In an embodiment, the transceiver of the network access node 600 may be a separate chipset or integrated with a processor in one chipset. While in some embodiments the processor, transceiver, and memory of network access node 600 are integrated in one chipset.

The client device 700 in the present disclosure includes, but is not limited to: UEs, such as smart phones, cellular phones, cordless phones, Session Initiation Protocol (SIP) phones, Wireless Local Loop (WLL) stations, Personal Digital Assistants (PDAs), handheld devices with wireless communication capabilities, computing or other processing devices connected to wireless modems, vehicle-mounted devices, wearable devices, Integrated Access and Backhaul (IAB) nodes, such as mobile cars or devices installed in cars, drones, device-to-device (D2D) devices, wireless cameras, mobile stations, access terminals, subscriber units, wireless communication devices, Wireless Local Area Network (WLAN) stations, wireless-enabled tablets, laptop devices, universal serial bus (universal serial bus embedded bus, USB), a wireless Customer Premises Equipment (CPE), and/or a chipset. In an Internet of things (IOT) scenario, client device 700 may represent a machine or other device or chipset that performs communications with other wireless devices and/or network devices.

It should be understood that in some cases, the client device 700 may be part of a second communication device. However, in some other cases, the client device 700 may be part of the first communication device. Which is a non-limiting example in this disclosure.

The UE may also be referred to as a mobile phone, a cellular phone, a computer tablet, or a laptop with wireless capabilities. In this context, a UE may be, for example, a portable, pocket-storage, hand-held, computer-comprised, or vehicle-mounted mobile device capable of communicating voice and/or data with another entity (e.g., another receiver or server) via a radio access network. A UE may be a Station (STA), which is any device that includes an IEEE 802.11 compliant Medium Access Control (MAC) and physical layer (PHY) interface to the Wireless Medium (WM). The UE may also be used for communication in 3 GPP-related LTE and LTE-Advanced, in Worldwide Interoperability for Microwave Access (WiMAX) and its evolution, and in fifth generation wireless technologies such as NR.

The processors of client device 700 may be referred to as one or more general purpose Central Processing Units (CPUs), one or more Digital Signal Processors (DSPs), one or more application-specific integrated circuits (ASICs), one or more Field Programmable Gate Arrays (FPGAs), one or more programmable logic devices, one or more discrete gates, one or more transistor logic devices, one or more discrete hardware components, and one or more chipsets.

The memory of client device 700 may be read-only memory, random access memory, or non-volatile random access memory (NVRAM).

The transceiver of client device 700 may be a transceiver circuit, a power controller, an antenna, or an interface to communicate with other modules or devices. In an embodiment, the transceiver of the client device 700 may be a separate chipset or integrated with a processor in a chipset. While in some embodiments the processor, transceiver, and memory of the client device 700 are integrated in one chipset.

The wireless communication systems in the present disclosure include, but are not limited to: LTE, 5G, or future wireless communication systems.

In addition, any of the methods according to embodiments of the present disclosure may be implemented in a computer program with code means, which when run by processing means causes the processing means to perform the method steps. The computer program is embodied in a computer readable medium of a computer program product. The computer-readable medium may include substantially any memory, such as a read-only memory (ROM), a programmable read-only memory (PROM), an Erasable PROM (EPROM), a flash memory, an Electrically Erasable PROM (EEPROM), or a hard drive.

Furthermore, the skilled person realizes that embodiments of the first communication device 100 and the second communication device 300 comprise necessary communication capabilities in the form of functions, means, units, elements, etc. for performing the technical solution. Examples of other such components, units, elements and functions are: processors, memories, buffers, control logic, encoders, decoders, rate matchers, de-rate matchers, mapping units, multipliers, decision units, selection units, switches, interleavers, de-interleavers, modulators, demodulators, inputs, outputs, antennas, amplifiers, receiving units, transmitting units, DSPs, MSDs, TCM encoders, TCM decoders, power supply units, power feeders, communication interfaces, communication protocols, etc., suitably arranged together to implement a technical solution.

In particular, the processors of the first communication device 100 and the second communication device 300 may include one or more instances of a Central Processing Unit (CPU), a Processing Unit, a Processing Circuit, a processor, an Application Specific Integrated Circuit (ASIC), a microprocessor, or other Processing logic that may interpret and execute instructions.

The expression "processor" may thus denote a processing circuit comprising a plurality of processing circuits, such as any, some or all of the above-listed items. The processing circuitry may also perform data processing functions for inputting, outputting, and processing data, including data buffering and device control functions, such as call processing control, user interface control, and the like.

Finally, it is to be understood that the disclosure is not limited to the embodiments described above, but also relates to and incorporates all embodiments within the scope of the appended independent claims.

Claims

1. A first communication device (100) for a wireless communication system (500), the first communication device (100) being configured to:

obtaining M modulation symbols, wherein M is a positive integer;

obtaining a discrete fourier transform, DFT, precoder input (122), wherein the DFT precoder input (122) is obtained by multiplying each element in each block with an element in the one or more spreading sequences, at least two elements of the one or more spreading sequences being different in at least one block; and

providing the DFT precoder input (122) to a DFT precoder (130).

2. The first communication device (100) of claim 1, wherein there is at least one block, wherein elements in the block are determined by dividing a length N_SFThe elements in the spreading sequence of (2) are multiplied by the same modulation symbol.

3. The first communication device (100) according to claim 1 or 2, wherein the first communication device (100) is configured to:

at least one block is arranged to include less than M modulation symbols.

4. The first communication device (100) according to any of claims 1 to 3, wherein the first communication device (100) is configured to:

5. First communication device (100) according to any of claims 1 to 4, wherein the one or more lengths are obtained as N_SFThe spreading sequence of (a) comprises:

obtaining a length of N_SFA single spreading sequence of (a); the first communication device (100) is further configured to:

6. The first communication device (100) of claim 4 or 5, wherein the DFT precoder input (122) is formed by M-N_SFGiven as individual elements, the elements are arranged as:

wherein,

representing elements in the ith spreading sequence

Representing the M modulation symbols.

7. The first communication device (100) according to any of claims 1 to 4, wherein the first communication device (100) is configured to:

obtaining mOrthogonal spreading sequences, wherein each spreading sequence has a length of N_SF，1＜m≤M；

Correlating the m orthogonal spreading sequences to different blocks;

8. The first communications device (100) of claim 7, wherein said M orthogonal spreading sequences form a length of M-N_SFThe composite spreading sequence of (a), the composite spreading sequence being arranged to have N_SFAnd orthogonal composite spreading sequences.

9. The first communication device (100) according to claim 7 or 8, wherein the m orthogonal spreading sequences are determined by a predefined rule.

10. The first communication device (100) of any of the previous claims, wherein the one or more spreading sequences are any spreading sequence in the group comprising:

DFT sequence set;

a cyclically shifted Zadoff-Chu sequence set;

a Hadamard sequence set;

slepian sequence set; and

11. The first communication device (100) according to any of the preceding claims, wherein the first communication device (100) is configured to:

mapping the DFT precoder output (132) to an input (140) of an Inverse Discrete Fourier Transform (IDFT); and

-deriving a signal (510) for transmission from an output of the IDFT (150);

transmitting the signal (510) to a second communication device (300).

12. The first communication device (100) of claim 11, wherein mapping the DFT precoder output (132) to an input of the IDFT (150) comprises:

mapping the DFT precoder output (132) to a set of non-contiguous resource blocks.

13. The first communication device (100) of claim 10 or 11, wherein the first communication device (100) is configured to provide an index of the one or more spreading sequences in at least one of:

radio resource control signaling;

an uplink control channel;

a downlink control channel;

media access control signaling; and

an allocation of time-frequency resources for transmission of the signal (510).

14. The first communication device (100) of any of the preceding claims, wherein the M modulation symbols are associated with any of:

uplink control information;

downlink control information;

uplink data information; or

And downlink data information.

15. A second communication device (300) for a wireless communication system (500), the second communication device (300) being configured to:

receiving a signal (510) from a first communication device (100);

obtaining M blocks from the received signal (510), where M is a positive integer and M.N_SFThe elements are arranged in M blocks, each block including N_SFAn element; and

demodulating and decoding the summed despread symbols.

16. A method (200) for a first communication device (100), the method (200) comprising:

obtaining (202) M modulation symbols, wherein M is a positive integer;

acquiring (204) one or more spreading sequences, wherein each spreading sequence has a length N_SF，N_SFIs a positive integer;

obtaining (206) M.N from the M modulation symbols_SFAn element, wherein, the M.N_SFThe elements are arranged in M blocks, each block comprising N_SFAn element;

obtaining (208) a discrete fourier transform, DFT, precoder input (122), wherein the DFT precoder input (122) is obtained by multiplying each element in each block with an element in the one or more spreading sequences, at least two elements of the one or more spreading sequences being different in at least one block; and

providing (210) the DFT precoder input (122) to a DFT precoder (130).

17. A method (400) for a second communication device (300), the method (400) comprising:

receiving (402) a signal (510) from a first communication device (100);

acquiring (404) one or more spreading sequences, wherein each spreading sequence has a length N_SF，N_SFIs a positive integer;

obtaining (406) M blocks from the received signal (510), where M is a positive integer and M.N_SFThe elements are arranged in M blocks, each block including N_SFAn element; and

despreading (408) the symbols in each block by multiplying each symbol with an element in the one or more spreading sequences and adding despread symbols corresponding to the same modulation symbol, wherein at least two elements in the one or more spreading sequences are different in at least one block; and

demodulating and decoding (410) the summed despread symbols.

18. An apparatus, comprising:

a processor; and

a memory coupled to the processor and having stored thereon processor-executable instructions that, when executed by the processor, cause the processor to perform the method of claim 16 or 17.