TRANSMISSION OF FASTER THAN NYQUIST SIGNALING

Abstract

Methods and apparatuses for UE initiated reporting in a wireless communication system. A method of operating a UE includes: transmitting UE capability information supporting a FTN; generating data modulation symbols including a set of zero symbols, wherein the data modulation symbols are up-sampled or zero-padded; performing, to obtain DFT output signal, a DFT spread operation on the up-sampled or the zero-padded data modulation symbols; performing, based on a target FTN compression rate and a SC allocation, a discarding or a down sampling operation on the DFT output signal, wherein the discarding or the down sampling operation generates a subset of DFT symbols; mapping the subset of DFT symbols to a set of SCs; and performing an IFFT operation on the subset of DFT symbols to obtain an FTN-DFT-S-OFDM signal including the target FTN compression rate comprising a positive rational number smaller than one.

Claims

1. A user equipment (UE) in a wireless communication system, the UE comprising: a transceiver; and a processor operably coupled to the transceiver, the processor configured to: generate data modulation symbols including a set of zero symbols, wherein the data modulation symbols are up-sampled or zero-padded, perform, to obtain DFT output signal, a discrete Fourier transform (DFT) spread operation on the up-sampled data modulation symbols or the zero-padded data modulation symbols, perform, based on (i) a target faster-than-Nyquist (FTN) compression rate and (ii) a subcarrier (SC) allocation, a discarding operation or a down sampling operation on the DFT output signal, wherein the discarding operation or the down sampling operation generates a subset of DFT symbols, map the subset of DFT symbols to a set of SCs corresponding to a transmission bandwidth, and perform an inverse fast Fourier transform (IFFT) operation on the subset of DFT symbols to obtain an FTN-DFT spread orthogonal frequency division multiplexing (FTN-DFT-S-OFDM) signal, wherein the FTN-DFT-S-OFDM signal corresponds to the target FTN compression rate, and wherein the target FTN compression rate is a positive rational number smaller than one.

2. The UE of claim 1, wherein: the processor is configured to transmit UE capability information indicating the UE is capable of supporting the FTN; and the processor is further configured to perform a frequency domain spectrum shaping (FDSS) operation on the subset of DFT symbols.

3. The UE of claim 1, wherein the processor is further configured to spread each of the data modulation symbols over the set of subcarriers that is scattered over an entire spectrum.

4. The UE of claim 1, wherein the processor is further configured to spread the data modulation symbols using the DFT spread operation and obtain consecutive DFT output signals.

5. The UE of claim 1, wherein the processor is further configured to: spread the data modulation symbols using the DFT spread operation and obtain different consecutive DFT output signals; and perform the IFFT operation to the different consecutive DFT output signals to obtain the FTN-DFT-S-OFDM signal, the IFFT operation including a set of zeros occupying unused subcarrier positions.

6. The UE of claim 1, wherein: the FTN-DFT-S-OFDM signal includes an OFDM symbol time, a number of sub-carriers, and a number of OFDM symbols per slot; the FTN-DFT-S-OFDM signal is transmitted or received over a mixed-FTN-DFT-S-OFDM slot that includes time divisions of FTN data symbols, none-FTN data symbols, and none-FTN reference signal (RS) symbols that are placed within a slot; and the FTN-DFT-S-OFDM signal is transmitted or received over an all-FTN-DFT-S-OFDM slot that includes the time divisions of FTN data symbols and none-FTN RS symbols that are placed within the slot.

7. The UE of claim 1, wherein the processor is further configured to: enable an FTN-inter-symbol interference (FTN-ISI) pre-canceling operation using a time windowing operation or a pre-equalization/pre-coding of reference signal (RS) symbols; and add soft edges to adjacent FTN-OFDM symbols with the RS symbols for the time windowing operation.

8. The UE of claim 1, wherein the processor is further configured to calculate the FTN compression rate based on a number of DFT output signals and a maximum number of symbols for the FTN-DFT-S-OFDM signal.

9. A method of a user equipment (UE) in a wireless communication system, the method comprising: transmitting UE capability information indicating the UE is capable of supporting a faster-than-Nyquist (FTN); generating data modulation symbols including a set of zero symbols, wherein the data modulation symbols are up-sampled or zero-padded; performing, to obtain DFT output signal, a discrete Fourier transform (DFT) spread operation on the up-sampled data modulation symbols or the zero-padded data modulation symbols; performing, based on (i) a target FTN compression rate and (ii) a subcarrier (SC) allocation, a discarding operation or a down sampling operation on the DFT output signal, wherein the discarding operation or the down sampling operation generates a subset of DFT symbols; mapping the subset of DFT symbols to a set of SCs corresponding to a transmission bandwidth; and performing an inverse fast Fourier transform (IFFT) operation on the subset of DFT symbols to obtain an FTN-DFT spread orthogonal frequency division multiplexing (FTN-DFT-S-OFDM) signal, wherein the FTN-DFT-S-OFDM signal includes the target FTN compression rate comprising a positive rational number smaller than one.

10. The method of claim 9, further comprising performing a frequency domain spectrum shaping (FDSS) operation on the subset of DFT symbols.

11. The method of claim 9, further comprising spreading each of the data modulation symbols over the set of subcarriers that is scattered over an entire spectrum.

12. The method of claim 9, further comprising spreading the data modulation symbols using the DFT spread operation and obtain consecutive DFT output signals.

13. The method of claim 9, further comprising: spreading the data modulation symbols using the DFT spread operation and obtain different consecutive DFT output signals; and performing the IFFT operation to the different consecutive DFT output signals to obtain the FTN-DFT-S-OFDM signal, the IFFT operation including a set of zeros occupying unused subcarrier positions.

14. The method of claim 9, wherein: the FTN-DFT-S-OFDM signal includes an OFDM symbol time, a number of sub-carriers, and a number of OFDM symbols per slot; the FTN-DFT-S-OFDM signal is transmitted or received over a mixed-FTN-DFT-S-OFDM slot that includes time divisions of FTN data symbols, none-FTN data symbols, and none-FTN reference signal (RS) symbols that are placed within a slot; and the FTN-DFT-S-OFDM signal is transmitted or received over an all-FTN-DFT-S-OFDM slot that includes the time divisions of FTN data symbols and none-FTN RS symbols that are placed within the slot.

15. The method of claim 9, further comprising: enabling an FTN-inter-symbol interference (FTN-ISI) pre-canceling operation using a time windowing operation or a pre-equalization/pre-coding of reference signal (RS) symbols; and adding soft edges to adjacent FTN-OFDM symbols with the RS symbols for the time windowing operation.

16. The method of claim 9, further comprising calculating the FTN compression rate based on a number of DFT output signals and a maximum number of symbols for the FTN-DFT-S-OFDM signal.

17. A base station (BS) in a wireless communication system, the BS comprising: a processor; and a transceiver operably coupled to the processor, the transceiver configured to receive, from a user equipment (UE), UE capability information indicating the UE is capable of supporting a faster-than-Nyquist (FTN), wherein: data modulation symbols including a set of zero symbols is generated, the data modulation symbols being up-sampled or zero-padded, a discrete Fourier transform (DFT) spread operation is performed to obtain DFT output signal on the up-sampled data modulation symbols or the zero-padded data modulation symbols, based on (i) a target faster-than-Nyquist (FTN) compression rate and (ii) a subcarrier (SC) allocation, a discarding operation or a down sampling operation is performed on the DFT output signal, the discarding operation or the down sampling operation generating a subset of DFT symbols, the subset of DFT symbols is mapped to a set of SCs corresponding to a transmission bandwidth, and an inverse fast Fourier transform (IFFT) operation is performed on the subset of DFT symbols to obtain an FTN-DFT spread orthogonal frequency division multiplexing (FTN-DFT-S-OFDM) signal, wherein the FTN-DFT-S-OFDM signal including the target FTN compression rate comprising a positive rational number smaller than one.

18. The BS of claim 17, wherein a frequency domain spectrum shaping (FDSS) operation is performed on the subset of DFT symbols.

19. The BS of claim 17, wherein: each of the data modulation symbols is spread over the set of subcarriers that is scattered over an entire spectrum; or the data modulation symbols using the DFT spread operation is spread to obtain consecutive DFT output signals.

20. The BS of claim 17, wherein: the FTN-DFT-S-OFDM signal includes an OFDM symbol time, a number of sub-carriers, and a number of OFDM symbols per slot; the FTN-DFT-S-OFDM signal is transmitted or received over a mixed-FTN-DFT-S-OFDM slot that includes time divisions of FTN data symbols, none-FTN data symbols, and none-FTN reference signal (RS) symbols that are placed within a slot; and the FTN-DFT-S-OFDM signal is transmitted or received over an all-FTN-DFT-S-OFDM slot that includes the time divisions of FTN data symbols and none-FTN RS symbols that are placed within the slot.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0012] For a more complete understanding of the present disclosure and its advantages, reference is now made to the following description taken in conjunction with the accompanying drawings, in which like reference numerals represent like parts:

[0013] FIG. 1 illustrates an example of wireless network according to embodiments of the present disclosure;

[0014] FIG. 2 illustrates an example of gNB according to embodiments of the present disclosure;

[0015] FIG. 3 illustrates an example of UE according to embodiments of the present disclosure;

[0016] FIGS. 4 and 5 illustrate example of wireless transmit and receive paths according to this disclosure;

[0017] FIG. 6 illustrates a flowchart of a method for FTN-DFT-S-OFDM to generate FTN based DFT-S-OFDM according to embodiments of the present disclosure;

[0018] FIG. 7 illustrates an example of Tx architecture for FTN-DFT-S-OFDM according to embodiments of the present disclosure;

[0019] FIG. 8 illustrates an example of Normalized signal of x(n) corresponding to data modulation symbol 0 and symbol 1 according to embodiments of the present disclosure;

[0020] FIG. 9 illustrates examples of Rx Architecture for FTN-DFT-S-OFDM according to embodiments of the present disclosure;

[0021] FIG. 10 illustrates examples of mixed-FTN-DFT-S-OFDM slot structure according to embodiments of the present disclosure;

[0022] FIG. 11 illustrates examples of all-FTN-DFT-S-OFDM slot structure according to embodiments of the present disclosure;

[0023] FIG. 12 illustrates examples of time-windowing of edge FTN symbols with index 3 and 10 for mixed-FTN-DFT-S-OFDM slot structure according to embodiments of the present disclosure;

[0024] FIG. 13 illustrates examples of time-windowing of adjacent FTN symbols with index 2, 4, 9 and 11 for all-FTN-DFT-S-OFDM slot structure according to embodiments of the present disclosure;

[0025] FIG. 14 illustrates a flowchart of a method for variation of FTN-DFT-S-OFDM to generate FTN based DFT-S-OFDM based on zero padding operation according to embodiments of the present disclosure;

[0026] FIG. 15 illustrates examples of variation of Tx architecture of FTN-DFT-S-OFDM based on zero padding operation according to embodiments of the present disclosure;

[0027] FIG. 16 illustrates a flowchart of a method for variation of FTN-DFT-S-OFDM to generate FTN based DFT-S-OFDM based on distributed subcarrier mapping according to embodiments of the present disclosure;

[0028] FIG. 17 illustrates examples of variation of Tx architecture of FTN-DFT-S-OFDM based on distributed subcarrier mapping according to embodiments of the present disclosure;

[0029] FIG. 18 illustrates an example of instantaneous PAPR CCDFs for QPSK/6RB without FDSS for FTN-DFT-S-OFDM and DFT-S-OFDM according to embodiments of the present disclosure; and

[0030] FIG. 19 illustrates a flowchart of a method for according to embodiments of the present disclosure.

DETAILED DESCRIPTION

[0031] FIG. 1 through FIG. 19, discussed below, and the various embodiments used to describe the principles of the present disclosure in this patent document are by way of illustration only and should not be construed in any way to limit the scope of the disclosure. Those skilled in the art will understand that the principles of the present disclosure may be implemented in any suitably arranged system or device.

[0032] To meet the demand for wireless data traffic having increased since deployment of 4G communication systems and to enable various vertical applications, 5G/NR communication systems have been developed and are currently being deployed. The 5G/NR communication system is considered to be implemented in higher frequency (mmWave) bands, e.g., 28 GHz or 60 GHz bands, so as to accomplish higher data rates or in lower frequency bands, such as 6 GHZ, to enable robust coverage and mobility support. To decrease propagation loss of the radio waves and increase the transmission distance, the beamforming, massive multiple-input multiple-output (MIMO), full dimensional MIMO (FD-MIMO), array antenna, an analog beam forming, large scale antenna techniques are discussed in 5G/NR communication systems.

[0033] In addition, in 5G/NR communication systems, development for system network improvement is under way based on advanced small cells, cloud radio access networks (RANs), ultra-dense networks, device-to-device (D2D) communication, wireless backhaul, moving network, cooperative communication, coordinated multi-points (COMP), reception-end interference cancelation and the like.

[0034] The discussion of 5G systems and frequency bands associated therewith is for reference as certain embodiments of the present disclosure may be implemented in 5G systems. However, the present disclosure is not limited to 5G systems, or the frequency bands associated therewith, and embodiments of the present disclosure may be utilized in connection with any frequency band. For example, aspects of the present disclosure may also be applied to deployment of 5G communication systems, 6G or even later releases which may use terahertz (THz) bands.

[0035] FIGS. 1-3 below describe various embodiments implemented in wireless communications systems and with the use of orthogonal frequency division multiplexing (OFDM) or orthogonal frequency division multiple access (OFDMA) communication techniques. The descriptions of FIGS. 1-3 are not meant to imply physical or architectural limitations to the manner in which different embodiments may be implemented. Different embodiments of the present disclosure may be implemented in any suitably arranged communications system.

[0036] FIG. 1 illustrates an example wireless network according to embodiments of the present disclosure. The embodiment of the wireless network shown in FIG. 1 is for illustration only. Other embodiments of the wireless network 100 could be used without departing from the scope of this disclosure.

[0037] As shown in FIG. 1, the wireless network includes a gNB 101 (e.g., base station, BS), a gNB 102, and a gNB 103. The gNB 101 communicates with the gNB 102 and the gNB 103. The gNB 101 also communicates with at least one network 130, such as the Internet, a proprietary Internet Protocol (IP) network, or other data network.

[0038] The gNB 102 provides wireless broadband access to the network 130 for a first plurality of user equipments (UEs) within a coverage area 120 of the gNB 102. The first plurality of UEs includes a UE 111, which may be located in a small business; a UE 112, which may be located in an enterprise; a UE 113, which may be a WiFi hotspot; a UE 114, which may be located in a first residence; a UE 115, which may be located in a second residence; and a UE 116, which may be a mobile device, such as a cell phone, a wireless laptop, a wireless PDA, or the like. The gNB 103 provides wireless broadband access to the network 130 for a second plurality of UEs within a coverage area 125 of the gNB 103. The second plurality of UEs includes the UE 115 and the UE 116. In some embodiments, one or more of the gNBs 101-103 may communicate with each other and with the UEs 111-116 using 5G/NR, long term evolution (LTE), long term evolution-advanced (LTE-A), WiMAX, WiFi, or other wireless communication techniques.

[0039] Depending on the network type, the term base station or BS can refer to any component (or collection of components) configured to provide wireless access to a network, such as transmit point (TP), transmit-receive point (TRP), an enhanced base station (eNodeB or eNB), a 5G/NR base station (gNB), a macrocell, a femtocell, a WiFi access point (AP), or other wirelessly enabled devices. Base stations may provide wireless access in accordance with one or more wireless communication protocols, e.g., 5G/NR 3rd generation partnership project (3GPP) NR, long term evolution (LTE), LTE advanced (LTE-A), high speed packet access (HSPA), Wi-Fi 802.11a/b/g/n/ac, etc. For the sake of convenience, the terms BS and TRP are used interchangeably in this patent document to refer to network infrastructure components that provide wireless access to remote terminals. Also, depending on the network type, the term user equipment or UE can refer to any component such as mobile station, subscriber station, remote terminal, wireless terminal, receive point, or user device. For the sake of convenience, the terms user equipment and UE are used in this patent document to refer to remote wireless equipment that wirelessly accesses a BS, whether the UE is a mobile device (such as a mobile telephone or smartphone) or is normally considered a stationary device (such as a desktop computer or vending machine).

[0040] Dotted lines show the approximate extents of the coverage areas 120 and 125, which are shown as approximately circular for the purposes of illustration and explanation only. It should be clearly understood that the coverage areas associated with gNBs, such as the coverage areas 120 and 125, may have other shapes, including irregular shapes, depending upon the configuration of the gNBs and variations in the radio environment associated with natural and man-made obstructions.

[0041] As described in more detail below, one or more of the UEs 111-116 include circuitry, programing, or a combination thereof, for a transmission of faster than Nyquist signaling in a wireless communication system. In certain embodiments, and one or more of the gNBs 101-103 includes circuitry, programing, or a combination thereof, for supporting a transmission of faster than Nyquist signaling in a wireless communication system.

[0042] Although FIG. 1 illustrates one example of a wireless network, various changes may be made to FIG. 1. For example, the wireless network could include any number of gNBs and any number of UEs in any suitable arrangement. Also, the gNB 101 could communicate directly with any number of UEs and provide those UEs with wireless broadband access to the network 130. Similarly, each gNB 102-103 could communicate directly with the network 130 and provide UEs with direct wireless broadband access to the network 130. Further, the gNBs 101, 102, and/or 103 could provide access to other or additional external networks, such as external telephone networks or other types of data networks.

[0043] FIG. 2 illustrates an example gNB 102 according to embodiments of the present disclosure. The embodiment of the gNB 102 illustrated in FIG. 2 is for illustration only, and the gNBs 101 and 103 of FIG. 1 could have the same or similar configuration. However, gNBs come in a wide variety of configurations, and FIG. 2 does not limit the scope of this disclosure to any particular implementation of a gNB.

[0044] As shown in FIG. 2, the gNB 102 includes multiple antennas 205a-205n, multiple transceivers 210a-210n, a controller/processor 225, a memory 230, and a backhaul or network interface 235.

[0045] The transceivers 210a-210n receive, from the antennas 205a-205n, incoming RF signals, such as signals transmitted by UEs in the network 100. The transceivers 210a-210n down-convert the incoming RF signals to generate IF or baseband signals. The IF or baseband signals are processed by receive (RX) processing circuitry in the transceivers 210a-210n and/or controller/processor 225, which generates processed baseband signals by filtering, decoding, and/or digitizing the baseband or IF signals. The controller/processor 225 may further process the baseband signals.

[0046] Transmit (TX) processing circuitry in the transceivers 210a-210n and/or controller/processor 225 receives analog or digital data (such as voice data, web data, e-mail, or interactive video game data) from the controller/processor 225. The TX processing circuitry encodes, multiplexes, and/or digitizes the outgoing baseband data to generate processed baseband or IF signals. The transceivers 210a-210n up-converts the baseband or IF signals to RF signals that are transmitted via the antennas 205a-205n.

[0047] The controller/processor 225 can include one or more processors or other processing devices that control the overall operation of the gNB 102. For example, the controller/processor 225 could control the reception of UL channel signals and the transmission of DL channel signals by the transceivers 210a-210n in accordance with well-known principles. The controller/processor 225 could support additional functions as well, such as more advanced wireless communication functions. For instance, the controller/processor 225 could support beam forming or directional routing operations in which outgoing/incoming signals from/to multiple antennas 205a-205n are weighted differently to effectively steer the outgoing signals in a desired direction. Any of a wide variety of other functions could be supported in the gNB 102 by the controller/processor 225.

[0048] The controller/processor 225 is also capable of executing programs and other processes resident in the memory 230, such as processes for supporting a transmission of faster than Nyquist signaling in a wireless communication system. The controller/processor 225 can move data into or out of the memory 230 as required by an executing process.

[0049] The controller/processor 225 is also coupled to the backhaul or network interface 235. The backhaul or network interface 235 allows the gNB 102 to communicate with other devices or systems over a backhaul connection or over a network. The interface 235 could support communications over any suitable wired or wireless connection(s). For example, when the gNB 102 is implemented as part of a cellular communication system (such as one supporting 5G/NR, LTE, or LTE-A), the interface 235 could allow the gNB 102 to communicate with other gNBs over a wired or wireless backhaul connection. When the gNB 102 is implemented as an access point, the interface 235 could allow the gNB 102 to communicate over a wired or wireless local area network or over a wired or wireless connection to a larger network (such as the Internet). The interface 235 includes any suitable structure supporting communications over a wired or wireless connection, such as an Ethernet or transceiver.

[0050] The memory 230 is coupled to the controller/processor 225. Part of the memory 230 could include a RAM, and another part of the memory 230 could include a Flash memory or other ROM.

[0051] Although FIG. 2 illustrates one example of gNB 102, various changes may be made to FIG. 2. For example, the gNB 102 could include any number of each component shown in FIG. 2. Also, various components in FIG. 2 could be combined, further subdivided, or omitted and additional components could be added according to particular needs.

[0052] FIG. 3 illustrates an example UE 116 according to embodiments of the present disclosure. The embodiment of the UE 116 illustrated in FIG. 3 is for illustration only, and the UEs 111-115 of FIG. 1 could have the same or similar configuration. However, UEs come in a wide variety of configurations, and FIG. 3 does not limit the scope of this disclosure to any particular implementation of a UE.

[0053] As shown in FIG. 3, the UE 116 includes antenna(s) 305, a transceiver(s) 310, and a microphone 320. The UE 116 also includes a speaker 330, a processor 340, an input/output (I/O) interface (IF) 345, an input 350, a display 355, and a memory 360. The memory 360 includes an operating system (OS) 361 and one or more applications 362.

[0054] The transceiver(s) 310 receives from the antenna 305, an incoming RF signal transmitted by a gNB of the network 100. The transceiver(s) 310 down-converts the incoming RF signal to generate an intermediate frequency (IF) or baseband signal. The IF or baseband signal is processed by RX processing circuitry in the transceiver(s) 310 and/or processor 340, which generates a processed baseband signal by filtering, decoding, and/or digitizing the baseband or IF signal. The RX processing circuitry sends the processed baseband signal to the speaker 330 (such as for voice data) or is processed by the processor 340 (such as for web browsing data).

[0055] TX processing circuitry in the transceiver(s) 310 and/or processor 340 receives analog or digital voice data from the microphone 320 or other outgoing baseband data (such as web data, e-mail, or interactive video game data) from the processor 340. The TX processing circuitry encodes, multiplexes, and/or digitizes the outgoing baseband data to generate a processed baseband or IF signal. The transceiver(s) 310 up-converts the baseband or IF signal to an RF signal that is transmitted via the antenna(s) 305.

[0056] The processor 340 can include one or more processors or other processing devices and execute the OS 361 stored in the memory 360 in order to control the overall operation of the UE 116. For example, the processor 340 could control the reception of DL channel signals and the transmission of UL channel signals by the transceiver(s) 310 in accordance with well-known principles. In some embodiments, the processor 340 includes at least one microprocessor or microcontroller.

[0057] The processor 340 is also capable of executing other processes and programs resident in the memory 360, such as processes for transmission of faster than Nyquist signaling in a wireless communication system.

[0058] The processor 340 can move data into or out of the memory 360 as required by an executing process. In some embodiments, the processor 340 is configured to execute the applications 362 based on the OS 361 or in response to signals received from gNBs or an operator. The processor 340 is also coupled to the I/O interface 345, which provides the UE 116 with the ability to connect to other devices, such as laptop computers and handheld computers. The I/O interface 345 is the communication path between these accessories and the processor 340.

[0059] The processor 340 is also coupled to the input 350 and the display 355 which includes for example, a touchscreen, keypad, etc., The operator of the UE 116 can use the input 350 to enter data into the UE 116. The display 355 may be a liquid crystal display, light emitting diode display, or other display capable of rendering text and/or at least limited graphics, such as from web sites.

[0060] The memory 360 is coupled to the processor 340. Part of the memory 360 could include a random-access memory (RAM), and another part of the memory 360 could include a Flash memory or other read-only memory (ROM).

[0061] Although FIG. 3 illustrates one example of UE 116, various changes may be made to FIG. 3. For example, various components in FIG. 3 could be combined, further subdivided, or omitted and additional components could be added according to particular needs. As a particular example, the processor 340 could be divided into multiple processors, such as one or more central processing units (CPUs) and one or more graphics processing units (GPUs). In another example, the transceiver(s) 310 may include any number of transceivers and signal processing chains and may be connected to any number of antennas. Also, while FIG. 3 illustrates the UE 116 configured as a mobile telephone or smartphone, UEs could be configured to operate as other types of mobile or stationary devices.

[0062] FIG. 4 and FIG. 5 illustrate example wireless transmit and receive paths according to this disclosure. In the following description, a transmit path 400 may be described as being implemented in a gNB (such as the gNB 102), while a receive path 500 may be described as being implemented in a UE (such as a UE 116). However, it may be understood that the receive path 500 can be implemented in a gNB and that the transmit path 400 can be implemented in a UE. In some embodiments, the receive path 500 is configured to support a transmission of faster than Nyquist signaling in a wireless communication system.

[0063] The transmit path 400 as illustrated in FIG. 4 includes a channel coding and modulation block 405, a serial-to-parallel (S-to-P) block 410, a size N inverse fast Fourier transform (IFFT) block 415, a parallel-to-serial (P-to-S) block 420, an add cyclic prefix block 425, and an up-converter (UC) 430. The receive path 500 as illustrated in FIG. 5 includes a down-converter (DC) 555, a remove cyclic prefix block 560, a serial-to-parallel (S-to-P) block 565, a size N fast Fourier transform (FFT) block 570, a parallel-to-serial (P-to-S) block 575, and a channel decoding and demodulation block 580.

[0064] As illustrated in FIG. 4, the channel coding and modulation block 405 receives a set of information bits, applies coding (such as a low-density parity check (LDPC) coding), and modulates the input bits (such as with quadrature phase shift keying (QPSK) or quadrature amplitude modulation (QAM)) to generate a sequence of frequency-domain modulation symbols.

[0065] The serial-to-parallel block 410 converts (such as de-multiplexes) the serial modulated symbols to parallel data in order to generate N parallel symbol streams, where N is the IFFT/FFT size used in the gNB 102 and the UE 116. The size N IFFT block 415 performs an IFFT operation on the N parallel symbol streams to generate time-domain output signals. The parallel-to-serial block 420 converts (such as multiplexes) the parallel time-domain output symbols from the size N IFFT block 415 in order to generate a serial time-domain signal. The add cyclic prefix block 425 inserts a cyclic prefix to the time-domain signal. The up-converter 430 modulates (such as up-converts) the output of the add cyclic prefix block 425 to an RF frequency for transmission via a wireless channel. The signal may also be filtered at baseband before conversion to the RF frequency.

[0066] A transmitted RF signal from the gNB 102 arrives at the UE 116 after passing through the wireless channel, and reverse operations to those at the gNB 102 are performed at the UE 116.

[0067] As illustrated in FIG. 5, the down converter 555 down-converts the received signal to a baseband frequency, and the remove cyclic prefix block 560 removes the cyclic prefix to generate a serial time-domain baseband signal. The serial-to-parallel block 565 converts the time-domain baseband signal to parallel time domain signals. The size N FFT block 570 performs an FFT algorithm to generate N parallel frequency-domain signals. The parallel-to-serial block 575 converts the parallel frequency-domain signals to a sequence of modulated data symbols. The channel decoding and demodulation block 580 demodulates and decodes the modulated symbols to recover the original input data stream.

[0068] Each of the gNBs 101-103 may implement a transmit path 400 as illustrated in FIG. 4 that is analogous to transmitting in the downlink to UEs 111-116 and may implement a receive path 500 as illustrated in FIG. 5 that is analogous to receiving in the uplink from UEs 111-116. Similarly, each of UEs 111-116 may implement the transmit path 400 for transmitting in the uplink to the gNBs 101-103 and may implement the receive path 500 for receiving in the downlink from the gNBs 101-103.

[0069] Each of the components in FIG. 4 and FIG. 5 can be implemented using only hardware or using a combination of hardware and software/firmware. As a particular example, at least some of the components in FIG. 4 and FIG. 5 may be implemented in software, while other components may be implemented by configurable hardware or a mixture of software and configurable hardware. For instance, the FFT block 570 and the IFFT block 415 may be implemented as configurable software algorithms, where the value of size N may be modified according to the implementation.

[0070] Furthermore, although described as using FFT and IFFT, this is by way of illustration only and may not be construed to limit the scope of this disclosure. Other types of transforms, such as discrete Fourier transform (DFT) and inverse discrete Fourier transform (IDFT) functions, can be used. It may be appreciated that the value of the variable N may be any integer number (such as 1, 2, 3, 4, or the like) for DFT and IDFT functions, while the value of the variable N may be any integer number that is a power of two (such as 1, 2, 4, 8, 16, or the like) for FFT and IFFT functions.

[0071] Although FIG. 4 and FIG. 5 illustrate examples of wireless transmit and receive paths, various changes may be made to FIG. 4 and FIG. 5. For example, various components in FIG. 4 and FIG. 5 can be combined, further subdivided, or omitted and additional components can be added according to particular needs. Also, FIG. 4 and FIG. 5 are meant to illustrate examples of the types of transmit and receive paths that can be used in a wireless network. Any other suitable architectures can be used to support wireless communications in a wireless network.

[0072] Discrete Fourier transform spreading OFDM (DFT-s-OFDM) is a single carrier waveform with low PAPR and could be a promising candidate waveform for B5G and 6G systems. Improving PAPR and spectral efficiency (SE) of DFT-s-OFDM may help with high data rate requirement of B5G and 6G systems.

[0073] FTN signaling increases the signaling rate of Sinc pulses by 25% and does not affect the minimum distance between binary coded codewords, which allows to increase the data rates without affecting the probability of error when using an optimum receiver. Constrained theoretical information rates of FTN provides that FTN is beneficial from an information theoretic perspective. As FTN signaling causes inter-symbol interference (ISI), achieving the full gains of theoretical rates may require higher-complexity receivers.

[0074] The FTN signaling was extended from single carrier to multicarrier and is combined with OFDM and is considered as a promising candidate waveform for next-generation communications systems.

[0075] The discrete Fourier transform-spread-OFDM (DFT-s-OFDM) has been adopted and commercialized as a key uplink waveform for the 3GPP 4G/5G mobile communication systems and widely regarded as the baseline waveform of B5G/6G systems. The DFT-S-OFDM achieves lower PAPR compared to OFDM and reduces power consumption and increase the coverage range.

[0076] To address the anticipated increase in wireless data traffic, the spectrally-efficient waveform is a key enabler. Conventionally, to boost the spectral efficiency (SE), higher-order modulation can be applied at the cost of larger PAPR, which makes reducing PAPR and enhancing SE contradictory. DFT-S-OFDM cannot improve the SE, whereas there are different PAPR reduction techniques for DFT-S-OFDM (such techniques may introduce signal distortion and sacrifice SE).

[0077] One way to enhance the SE of a waveform (e.g., DFT-S-OFDM), is to apply FTN signaling by increasing symbol rate while accepting additional inter-symbol interference (ISI). On the other hand, FTN may degrade symbol error rate (SER) and may increase Rx complexity. The disclosure is to introduce a waveform based on combining FTN and DFT-S-OFDM, which can enable to achieve higher SE and lower PAPR.

[0078] Reference signals (RS) can be utilized for coherent signal detection and channel estimation in FTN scenarios. The challenge is how to embed RS symbols with FTN symbols to support 4G/5G frame/subframe structure with backward compatibility. The disclosure introduces slot structure which can be incorporated into 4G/5G subframe/frame structure for the provided waveform. Therefore, the conventional DFT-S-OFDM enabled transceiver may transmit/receive such FTN waveform without compromising the original architecture of DFT-S-OFDM.

[0079] Finally, design flexibility on selecting FTN compression rates provides new degrees of freedom for the waveform to achieve different levels of SE. The specific set of feasible FTN compression rates for the waveform to support different numerologies and number of resource blocks (RBs) are explained in the present disclosure.

[0080] The present disclosure is related to a modification of DFT-S-OFDM to enhance SE and PAPR simultaneously, by incorporating FTN signaling to DFT-s-OFDM (FTN-DFT-S-OFDM). The FTN-DFT-S-OFDM enables the synthesis of block-based single carrier waveforms with various FTN compression rates and bandwidths (number of RBs) by up-sampling input data symbols and changing the size of the DFT-spread block. FTN-DFT-S-OFDM offers flexibility in slot design, and it is a backward compatible with 4G/5G subframe/frame structure. Moreover, frequency domain pulse shaping could be utilized as an enabling technique for FTN-DFT-S-OFDM to strike better SER, PAPR, SE, and complexity.

[0081] Additionally, different slot structures for FTN-DFT-S-OFDM to transmit reference signals (RS) is introduced to combine none-FTN RS symbols with FTN data symbols and/or with none-FTN data symbols. The Tx may encode the FTN-DFT-S-OFDM data symbols for transmission to the Rx in a subframe. Furthermore, a method for configuring FTN compression rates based on different numerology is disclosed.

[0082] Low implementation complexity and small modification of original architecture of DFT-S-OFDM, backward compatibility of subframe/frame structure can make FTN-DFT-S-OFDM a waveform candidate for B5G and 6G systems.

[0083] In one embodiment of the present disclosure, Tx (e.g., UE) utilizes up-sampling, DFT spreading and discarding operation to generate FTN signal and leverages the architecture of DFT-S-OFDM to configure different FTN compression rates flexibly.

[0084] FIG. 6 illustrates a flowchart of a method 600 for FTN-DFT-S-OFDM to generate FTN based DFT-S-OFDM according to embodiments of the present disclosure. The method 600 as may be performed by a UE (e.g., 111-116 as illustrated in FIG. 1). An embodiment of the method 600 shown in FIG. 6 is for illustration only. One or more of the components illustrated in FIG. 6 can be implemented in specialized circuitry configured to perform the noted functions or one or more of the components can be implemented by one or more processors executing instructions to perform the noted functions.

[0085] FIG. 6 illustrates a flowchart for a process 600 including an example of operations at Tx side to support FTN based DFT-S-OFDM. For example, the process 600 may be implemented using a transmit path, such as transmit path 400, in a UE, such as UE 116. An embodiment of the process 600 shown in FIG. 6 is for illustration only.

[0086] In one embodiment, at operation 601, the Q data modulation symbols are up-sampled by a factor of b and the bQ up-sampled symbols are DFT spread.

[0087] At operation 602, first M DFT outputs is selected and are mapped to the sub-carriers corresponding to the assigned transmission bandwidth.

[0088] At operation 603, the frequency domain pulse/spectrum shaping (FDSS) can be applied on the M DFT outputs and can be mapped to the corresponding subcarriers as input of IFFT.

[0089] At operation 604, the IFFT operation is performed; resulting in FTN compression rate of T=M/Q for the data modulation symbols.

[0090] Tx circuitry such as channel coding for data bits, cyclic prefix addition, digital-to-analog converter, analog filters, amplifiers, and transmitter antennas are not illustrated in the disclosure as they are well known in the art and are omitted for brevity.

[0091] FTN compression rate (=M/Q) is a positive rational number smaller than one, and can be expressed as an irreducible fraction

[00001]$=\frac{{}_{\mathrm{num}}}{{}_{\mathrm{den}}}$

where .sub.num and .sub.den may be co-prime positive integers. Then b can be chosen as any positive multiple factor of .sub.num to flexibly accommodate the desired DFT implementations constraints. In one design example, to have smaller DFT size, b can be assumed equal to .sub.num, i.e., b=.sub.num.

[0092] In case of M=Q (=1 or b=1, i.e., no up-sampling and discarding may be performed), FTN-DFT-S-OFDM can become equivalent to 4G/5G DFT-S-OFDM. In other words, FTN-DFT-S-OFDM is more general version of DFT-S-OFDM.

[0093] FIG. 7 illustrates an example of Tx architecture for FTN-DFT-S-OFDM 700 according to embodiments of the present disclosure. An embodiment of the Tx architecture for FTN-DFT-S-OFDM 700 shown in FIG. 7 is for illustration only.

[0094] FIG. 7 is an example of signal processing block diagram at Tx side to generate FTN-DFT-S-OFDM. In following, it can be shown that the output of IFFT (x(n)) can become equivalent to FTN signaling of DFT-S-OFDM. For brevity assumed the pulse shaping is Sinc pulse shape (i.e., no FDSS is applied).

[0095] Let's assume Q modulation (e.g., QAM) data symbols are: s=(S.sub.0, S.sup.1, . . . , S.sub.Q-1).sub.Q.

[0096] With some mathematical manipulation, it can be shown that M DFT outputs are,

[00002]$P\left(k\right)=D\left(k\right)=\frac{1}{bQ}\underset{q=0}{\overset{Q-1}{.Math.}}{s}_q{e}^{-jk\frac{2q}{bQ}},\mathrm{for}0kM-1.$

[0097] And output of IFFT (with assumption that first M input of N-IFFT are utilized for sub-carriers) can be modeled as single carrier transmission with overall pulse shape of g(n),

[00003]$x\left(n\right)=\frac{1}{bQ}{.Math.}_{q=0}^{Q-1}{s}_q.Math.g\left(n-q\frac{N}{Q}\right),\mathrm{where}g\left(n\right)={.Math.}_{k=0}^{M-1}{e}^{jn\frac{2k}{N}}.$

[0098] Each symbol (s.sub.q) is passed through g(n) with a symbol-interval of N/Q. The signal x(n) is then transmitted to the receiver over a channel after some common Tx operations.

[0099] The 4G/5G DFT-S-OFDM is considered as a baseline waveform, where its number of subcarriers equal to FTN-DFT-S-OFDM, M.sub.DFT-s-OFDM=M and its number of input symbols is, Q.sub.DFT-s-OFDM=M. Let's refer to DFT-S-OFDM's output signal as X.sub.DFT-s-OFDM(n) which is a Nyquist signal with symbol time of N/M.

[00004]$x_{\mathrm{DFT}-s-\mathrm{OFDM}}\left(n\right)=\frac{1}{M}{.Math.}_{q=0}^{M-1}{s}_q.Math.g\left(n-q\frac{N}{M}\right).$

[0100] However, FTN signal x(n) has smaller symbol time

[00005]$\frac{N}{Q}<\frac{N}{M}\left(\mathrm{as}Q>M\right)$

than DFT-S-OFDM for same pulse shape g(n) (which is orthogonal with respect to shifts

[00006]$q\frac{N}{M}).$

Therefore, symbol rate for x(n) becomes 1/=Q/M times higher than that X.sub.DFT-s-OFDM(n) leading to higher SE. In other words, with FTN-DFT-S-OFDM, SE is improved by multiplexing more data symbols compared to DFT-S-OFDM with same number of subcarriers. The orthogonality is no longer maintained between consecutive symbols in the FTN system due to the artificially induced ISI during transmission. Thus, FTN transmission achieves higher SE at the cost of some ISI.

[0101] FIG. 8 illustrates an example of normalized signal of x(n) 800 corresponding to data modulation symbol 0 and symbol 1 according to embodiments of the present disclosure. An embodiment of the normalized signal of x(n) 800 shown in FIG. 8 is for illustration only.

[0102] To illustrate the waveform shape of FTN-DFT-S-OFDM and DFT-S-OFDM, IFFT output of both architectures are illustrated in FIG. 8 for three different scenarios/examples (with assumption of Q=74, M=60, Q.sub.DFT-s-OFDM=60, M.sub.DFT-s-OFDM=60, N=N.sub.DFT-s-OFDM=4096): [0103] Symbol 0: s=(s.sub.0, 0, . . . , 0).sub.Q; [0104] Symbol 1: s=(0, s.sub.1, . . . , 0).sub.Q; and [0105] Symbol 0+1: s=(s.sub.0, s.sub.1, . . . , 0).sub.Q.

[0106] For illustration purposes, it is assumed that s.sub.0=s.sub.1. As can be seen from FIG. 8 top and bottom, pulse shapes for symbol 0 and symbol 1 are identical (except time shift); and symbol 0 (triangle) is sent at sample 0 for both FTN-DFT-S-OFDM and DFT-S-OFDM. However, symbol 1 (donut) is sent around

[00007]$\frac{N}{M}=68.2$

for DFT-S-OFDM while for FTN-DFT-S-OFDM, symbol 1 (donut) is sent earlier around

[00008]$\frac{N}{Q}=55.3.$

In other words, symbol 1 for FTN-DFT-S-OFDM is sent quicker and symbol rate is increased with ratio of 1/=Q/M=1.23 compared to DFT-S-OFDM. As from this example can be seen the peak value of symbol 0+1 (solid line) is smaller for FTN-DFT-S-OFDM compared to DFT-S-OFDM, leading to PAPR improvement for FTN-DFT-S-OFDM.

[0107] Similar to conventional FTN signaling, part of the data spectrum may be truncated due to signal processing operations 601 and 602 of FIG. 6. This does not necessarily mean that the data are lost, as the increased symbol rate in FTN above the Nyquist limit can be exploited in time domain to add redundancies in the data to recover the lost spectrum by means of error control coding.

[0108] An exemplary block diagram of the Rx functions for FTN-DFT-S-OFDM is illustrated in FIG. 9. At the Rx, the reverse operations of those illustrated in FIG. 7 are performed. In this example, the generic low-complexity time-domain equalization-based method is utilized based on knowledge of channel estimation and Tx side FDSS.

[0109] FIG. 9 illustrates examples of Rx architecture for FTN-DFT-S-OFDM 900 according to embodiments of the present disclosure. An embodiment of the Rx architecture for FTN-DFT-S-OFDM 900 shown in FIG. 9 is for illustration only.

[0110] To reduce long DFT sizes (bQ), while allowing flexibility in the choice of b values, the sum of multiple DFTs could be utilized, where b identical DFT blocks each of length Q instead of one large DFT block of length bQ. This may help with parallel computation and may reduce the computation time required for the DFT processing stage.

[0111] The above-mentioned embodiment and given variations are examples and not restrictive to the disclosure. Other variations are possible.

[0112] Besides SE improvement, FTN-DFT-s-OFDM could reduce PAPR levels for larger FTN compression rates; due to the non-orthogonality between pulse-shapes, the overlapping between sidelobes of pulse becomes lighter than that of DFT-s-OFDM. On the other hand, with further decrease of FTN compression rate, the overlapping between the main lobes of the adjacent pulses becomes larger leading to increased PAPR. Therefore, some lighter FTN compression rates could achieve the higher PAPR gains.

[0113] Rx's equalizer complexity and SER performance of FTN-DFT-S-OFDM could be worsen with the number of the interfering symbols. By incorporating FDSS that has more finite time domain response, lower FTN ISI and PAPR could be achieved compared to Sinc pulse shapes.

[0114] A UE may indicate the FTN feature support (and potentially a set of supported FTN compression rates) through UE capability information. Once gNB knows that the UE supports FTN feature, it may indicate the UE on whether to apply FTN signaling for downlink or uplink or both directions, using downlink control indicator (DCI) or medium access control element (MAC CE) or radio resource configuration (RRC) message. The gNB may indicate the exact FTN compression rate that UE could utilize it.

[0115] The transmission bandwidth per Tx/UE is assumed to include i number of RBs (i.e., i is a positive integer bigger or equal to one), where an exemplary embodiment assumes that each RB has 12 subcarriers and transmitters are allocated i=M/12 of consecutive or distributed RBs. Nevertheless, the above values are only illustrative and not restrictive to the embodiment.

[0116] As discussed in the present disclosure, no asymptotic error rate is lost by increasing the symbol rate 24.7% above the Nyquist limit, and hence the feasible FTN compression rates are restricted to satisfy the Mazo limit

[00009]$\left(i.e.,\frac{1-}{}<0.2471\right)$

for case of no FDSS. With such condition, maximum number of symbols for FTN-DFT-S-OFDM can be calculated as Q.sub.max=1.247*12*i=1.4.964*i where is a floor function. Therefore, different feasible FTN compression rates can be achieved according to =M/Q; and minimum FTN compression rate can be calculated as, .sub.min=M/Q.sub.max.

[0117] In case that FDSS is utilized, the limitation may increase, and hence different FTN compression rates could be realized.

[0118] TABLE 1 illustrates the feasible FTN compression rates for different RB sizes for case of no FDSS. For any RB size, FTN compression rates of 12/13, 6/7 are feasible examples, achieving low SE and high SE. For any even size RB (0i (mod 2)) 24/25, 8/9, 24/29 could be applied. For any RB size that 0i (mod 3) following FTN compression rates could be examples of FTN compression rate 36/37, 18/19, 12/13, 9/10, 36/41, 6/7, 36/43, 8/11.

TABLE-US-00001 TABLE 1 Example of Feasible FTN compression Rates as function of number of RBs 1-5 number of Number of Maximum number FTN compression rate = number of symbols/number of RBs = i subcarriers = 12i of symbols subcarriers 1 12 14 12/13, 6/7 2 24 29 24/25, 12/13, 8/9, 6/7, 24/29 3 36 44 36/37, 18/19, 12/13, 9/10, 36/41, 6/7, 36/43, 8/11 4 48 59 48/49, 24/25, 16/17, 12/13, 48/53, 8/9, 48/55, 6/7, 16/19, 24/29, 48/59 5 60 74 60/61, 30/31, 20/21, 15/16, 12/13, 10/11, 60/67, 15/17, 20/23, 6/7, 60/71, 5/6, 60/73, 30/37

[0119] The embodiments of the present disclosure for FTN-DFT-S-OFDM is applicable in general to transmitting data and/or signaling/control information.

[0120] Performance of a receiver could be degraded without the availability of an accurate channel estimation. An embodiment of the disclosure may improve with the accuracy of channel estimation for FTN (e.g., FTN-DFT-S-OFDM) with two different examples of slot structures that they can support different 5G numerologies, and compatible with 4G/5G subframe/frame structure. Additionally, FTN-ISI pre-canceling techniques could be utilized to either of slot structure to remove any residual FTN-ISI impacting reference signal (RS) symbols in Tx side.

[0121] A number of consecutive OFDM symbols per slot for normal cyclic prefix is assumed to be 14 (with index of 0 to 13). The length of one OFDM Symbol (without cyclic prefix) is inverse of subcarrier spacing corresponding to numerology that is configured regardless of if it is an FTN symbol or none-FTN symbol. The embodiments of the disclosure are applicable to any block/slot based OFDM transmission (e.g., for 4G/5G extended cyclic prefix-based slot with 12 OFDM symbols).

[0122] In both slot structure examples, OFDM symbol time is unchanged compared to DFT-S-OFDM for a given numerology, and hence number of OFDM symbols per slot is also unchanged. Moreover, transmission bandwidth or equivalently number of sub-carriers are unchanged. The backward slot compatibility may help FTN-DFT-S-OFDM a waveform candidate for B5G and 6G systems.

[0123] First variant of the slot structure is mixed-FTN-DFT-S-OFDM in which, time divisions of FTN data symbols, none-FTN data symbols and none-FTN RS symbols are placed within a slot. Tx/UE transmits the data symbols for transmission in a slot over a channel (e.g., PUSCH), wherein FTN-data symbols is utilized for the central OFDM symbols of slot (index of 3-10), and the none-FTN-data symbols is utilized for the edge symbols in the slot (index of 0, 2, 11, and 13). Two RS symbols are located in OFDM index of 1 and 12. FIG. 10 illustrates such slot structure.

[0124] FIG. 10 illustrates examples of mixed-FTN-DFT-S-OFDM slot structure 1000 according to embodiments of the present disclosure. An embodiment of the mixed-FTN-DFT-S-OFDM slot structure 1000 shown in FIG. 10 is for illustration only.

[0125] Both FTN and none-FTN data symbols may have different number of modulation symbols with same number of subcarriers. Thus, the encoded bits length may be different for FTN and none-FTN symbols if identical modulation and coding scheme is assumed among them. Symbol duration, number of OFDM symbols per slot, and number of subcarriers are unchanged compared to DFT-S-OFDM; however, number of data modulation symbols for FTN symbols are increased according to FTN compression rate. Overall slot-spectral efficiency for mixed-FTN-DFT-S-OFDM (SE.sub.slot.sup.mixed) is calculated by the following equation based on slot-spectral efficiency of 4G/5G DFT-S-OFDM (SE.sub.slot.sup.NR)

[00010]$S{E}_{\mathrm{slot}}^{mixed}=\left(\frac{3}{7}+\frac{4}{7}\right)S{E}_{\mathrm{slot}}^{NR}.$

[0126] Owing to the presence of two non-FTN symbols around of RS symbols, RS could be less susceptible to the ISI from FTN data symbols. Mixed-FTN-DFT-S-OFDM also suppresses inter-slot interreference between two slots whose may belong to same user or different users/systems by utilizing 3+3 none-FTN symbols as a guard (between FTN data symbols of two slots). This enables none-FTN system to coexist with FTN system (e.g., FTN-DFT-S-OFDM). The FTN-ISI within the central OFDM symbols could be equalized by FTN equalizer in Rx or/and Tx.

[0127] TABLES 2, 3, and 4 are illustrating details of exemplary Mixed-FTN-DFT-S-OFDM slot structures for three different FTN compression rates

[00011]$=\frac{12}{13},=\frac{8}{9}\mathrm{and}=\frac{6}{7},$

respectively, based on processing operation 600 as illustrated in FIG. 6.

[0128] For any RB size, FTN compression rates of 12/13 and 6/7 are feasible examples, satisfying Mazo limit and achieving low SE and high SE, respectively. While moderate FTN compression rate of 8/9 is more suitable for any even RB sizes.

[0129] TABLES 2, 3, and 4 are visualizing two RS symbols located in 1.sup.st and 12.sup.th symbols of slot, and rest could be data symbols. However, symbols 0-2 and 11-13 including RS symbols are not exploiting FTN. It is assumed that number of subcarriers/RBs (bandwidth) for symbols of slot are equal, while number of modulation data symbols could be different whether FTN is applied or not. DFT size could be different between none-FTN symbols and FTN symbols. All three tables are representing an example of 4 RB (or equivalently M=48 subcarriers are allocated for each of 14 symbols), while for

[00012]$=\frac{12}{13}\left(\mathrm{Table}2\right)\mathrm{and}=\frac{6}{7}\left(\mathrm{Table}4\right)$

any RB size can be selected. For

[00013]$=\frac{8}{9}\left(\mathrm{Table}4\right),$

only even-sized RB could be applied. IFFT size is assumed to be 1024 for all of slot symbols.

[0130] TABLE 2 for

[00014]$=\frac{12}{13}:$

based on

[00015]$=\frac{M}{Q},$

number of data modulation symbols for FTN symbols is Q=52. While, none-FTN data symbols has 48 data symbols. Number of subcarriers, regardless of FTN, none-FTN data symbols and RS symbols are 48. With assumption of b=.sub.num=12, DFT size equals to b*Q=12*52=624 for FTN-data symbols and 48 for none-FTN data symbols.

[0131] TABLE 3 for

[00016]$=\frac{8}{9}:$

based on

[00017]$=\frac{M}{Q},$

number of data modulation symbols for FTN symbols is Q=54. While, none-FTN data symbols has 48 data symbols. Number of subcarriers, regardless of FTN, none-FTN data symbols and RS symbols are 48. With assumption of b=.sub.num=8, DFT size equals to b*Q=8*54=432 for FTN-data symbols and 48 for none-FTN data symbols.

[0132] TABLE 4 for

[00018]$=\frac{6}{7}:$

based on relationship of

[00019]$=\frac{M}{Q},$

number of data modulation symbols for FTN symbols is Q=56. While, none-FTN data symbols has 48 data symbols. Number of subcarriers, regardless of FTN, none-FTN data symbols and RS symbols are 48. With assumption of b=.sub.num=6, DFT size equals to b+Q=6*56=336 for FTN-data symbols and 48 for none-FTN data symbols.

TABLE-US-00002 TABLE 2 Example of slot-structure of FTN-DFT-S-OFDM for Mixed-FTN-DFT-S-OFDM with = 12/13, 4 RB for subcarriers are utilized Symbol Index 0 1 2 3 4 5 6 7 8 9 10 11 12 13 FTN No No No Yes Yes Yes Yes Yes Yes Yes Yes No No No Data/Reference D RS D D D D D D D D D D RS D signal (D/RS) Num. of Mod. 48 48 52 52 52 52 52 52 52 52 48 48 Symbols Num. of Sub- 48 48 48 48 48 48 48 48 48 48 48 48 48 48 carriers DFT size 48 48 624 624 624 624 624 624 624 624 48 48

TABLE-US-00003 TABLE 3 Example of slot-structure of FTN-DFT-S-OFDM for Mixed-FTN-DFT-S-OFDM with = 8/9, 4 RB for subcarriers are utilized Symbol Index 0 1 2 3 4 5 6 7 8 9 10 11 12 13 FTN No No No Yes Yes Yes Yes Yes Yes Yes Yes No No No Data/Reference D RS D D D D D D D D D D RS D signal (D/RS) Num. of Mod. 48 48 54 54 54 54 54 54 54 54 48 48 Symbols Num. of Sub- 48 48 48 48 48 48 48 48 48 48 48 48 48 48 carriers DFT size 48 48 432 432 432 432 432 432 432 432 48 48

TABLE-US-00004 TABLE 4 Example of slot-structure of FTN-DFT-S-OFDM for Mixed-FTN-DFT-S-OFDM with = 6/7, 4 RB for subcarriers are utilized Symbol Index 0 1 2 3 4 5 6 7 8 9 10 11 12 13 FTN No No No Yes Yes Yes Yes Yes Yes Yes Yes No No No Data/Reference D RS D D D D D D D D D D RS D signal (D/RS) Num. of Mod. 48 48 56 56 56 56 56 56 56 56 48 48 Symbols Num. of Sub- 48 48 48 48 48 48 48 48 48 48 48 48 48 48 carriers DFT size 48 48 336 336 336 336 336 336 336 336 48 48

[0133] Second variant of slot structure is all-FTN-DFT-S-OFDM in which, is time divisions of FTN data symbols and none-FTN RS symbols within slot. The Tx/UE transmits the FTN-DFT-S-OFDM data symbols, wherein the slot includes two RS symbols in 3.sup.rd and 10.sup.th symbol, and rest of symbols (0-2; 4-9; 11-13) in the slot are transmitted in accordance with FTN-DFT-S-OFDM. Symbol duration, number of OFDM symbols per slot, and number of subcarriers are unchanged compared to DFT-S-OFDM; however, number of data modulation symbols for FTN symbols are increased according to FTN compression rate. FIG. 11 is illustrating such slot structure.

[0134] FIG. 11 illustrates examples of all-FTN-DFT-S-OFDM slot structure 1100 according to embodiments of the present disclosure. An embodiment of the method 1100 shown in FIG. 11 is for illustration only.

[0135] This slot structure offers higher slot spectral-efficiency than mixed-FTN-DFT-S-OFDM. The SE of all-FTN-DFT-S-OFDM can be calculated as follows based on slot-spectral efficiency of 4G/5G DFT-S-OFDM (SE.sub.slot.sup.NR):

[00020]$S{E}_{\mathrm{slot}}^{all}=\left(\frac{1}{7}+\frac{6}{7}\right)S{E}_{\mathrm{slot}}^{NR}.$

[0136] TABLES 5, 6, and 7 are illustrating details of exemplary all-FTN-DFT-S-OFDM slot structures for three different FTN compression rates

[00021]$=\frac{12}{13},=\frac{8}{9}\mathrm{and}=\frac{6}{7},$

respectively, based on an embodiment of the present disclosure shown in FIG. 6. For any RB size, FTN compression rates of 12/13 and 6/7 are feasible examples, satisfying Mazo limit and achieving low SE and high SE, respectively. While moderate FTN compression rate of 8/9 is more suitable for any even RB sizes.

[0137] TABLES 5, 6, and 7 are showing that two RS symbols are located in 3.sup.rd and 10.sup.th symbols of slot, and rest could be data FTN symbols. RS symbols are not utilizing FTN operation. All three tables are representing an example of 4 RB (or equivalently M=48 subcarriers are allocated for each of slot symbols), while for table 5

[00022]$\left(=\frac{12}{13}\right)$

any 7

[00023]$\left(=\frac{6}{7}\right)$

any RB size can be selected with. For Table 6

[00024]$\left(=\frac{8}{9}\right),$

only even-sized RB could be applied. FFT size is assumed to be 1024 for symbols of slot.

[0138] TABLE 5 for

[00025]$T=\frac{12}{13}:$

based on

[00026]$=\frac{M}{Q},$

number of data modulation symbols for FTN symbols is Q=52, while number of data modulation symbols for none-FTN symbols is 48. Number of subcarriers, regardless of FTN, or none-FTN data symbols and RS symbols are 4RB/48. With assumption of b=.sub.num=12, DFT size equals to b*Q=12*52=624 for FTN-data symbols, and DFT size for none-FTN symbols is 48.

[0139] TABLE 6 for

[00027]$=\frac{8}{9}:$

based on

[00028]$=\frac{M}{Q},$

number of data modulation symbols for FTN symbols is Q=54, while number of data modulation symbols for none-FTN symbols is 48. Number of subcarriers, regardless of FTN, or none-FTN data symbols and RS symbols are 4RB/48. With assumption of b=.sub.num=8, DFT size equals to b*Q=8*54=432 for FTN-data symbols, and DFT size for none-FTN symbols is 48.

[0140] TABLE 7 for

[00029]$=\frac{6}{7}:$

based on

[00030]$=\frac{M}{Q},$

number of data modulation symbols for FTN symbols is Q=56, while number of data modulation symbols for none-FTN symbols is 48. Number of subcarriers, regardless of FTN, or none-FTN data symbols and RS symbols are 48. With assumption of b=.sub.num=6. DFT size equals to b*Q=6*56=336 for FTN-data symbols, and DFT size for none-FTN symbols is 48.

TABLE-US-00005 TABLE 5 Example of slot-structure of FTN-DFT-S-OFDM for Mixed-FTN-DFT-S-OFDM with = 12/13, 4 RB for subcarriers are utilized Symbol Index 0 1 2 3 4 5 6 7 8 9 10 11 12 13 FTN Yes Yes Yes No Yes Yes Yes Yes Yes Yes No Yes Yes Yes Data/Reference D D D RS D D D D D D RS D D D signal (D/RS) Num. of Mod. 52 52 52 52 52 52 52 52 52 52 52 52 Symbols Num. of Sub- 48 48 48 48 48 48 48 48 48 48 48 48 48 48 carriers DFT size 624 624 624 624 624 624 624 624 624 624 624 624

TABLE-US-00006 TABLE 6 Example of slot-structure of FTN-DFT-S-OFDM for ALL-FTN-DFT-S-OFDM with = 8/9, 4 RB for subcarriers are utilized Symbol Index 0 1 2 3 4 5 6 7 8 9 10 11 12 13 FTN Yes Yes Yes No Yes Yes Yes Yes Yes Yes No Yes Yes Yes Data/Reference D D D RS D D D D D D RS D D D signal (D/RS) Num. of Mod. 54 54 54 54 54 54 54 54 54 54 54 54 Symbols Num. of Sub- 48 48 48 48 48 48 48 48 48 48 48 48 48 48 carriers DFT size 432 432 432 432 432 432 432 432 432 432 432 432

TABLE-US-00007 TABLE 7 Example of slot-structure of FTN-DFT-S-OFDM for ALL-FTN-DFT-S-OFDM with = 6/7, 4 RB for subcarriers are utilized Symbol Index 0 1 2 3 4 5 6 7 8 9 10 11 12 13 FTN Yes Yes Yes No Yes Yes Yes Yes Yes Yes No Yes Yes Yes Data/Reference D D D RS D D D D D D RS D D D signal (D/RS) Num. of Mod. 56 56 56 56 56 56 56 56 56 56 56 56 Symbols Num. of Sub- 48 48 48 48 48 48 48 48 48 48 48 48 48 48 carriers DFT size 336 336 336 48 336 336 336 336 336 336 48 336 336 336

[0141] TABLE 8 compares SE of slot examples for different FTN compression rates. As it can be seen, the SE of all-FTN-DFT-S-OFDM slot is higher than mixed-FTN-DFT-S-OFDM for given FTN compression rate. Additionally, with reducing FTN compression rate, the SE is increasing.

TABLE-US-00008 TABLE 8 SE Improvement compared to DFT-S-OFDM per Slot structure and per FTN compression Rate FTN compression rate 12/13 8/9 6/7 Mixed-FTN-DFT-OFDM 4.7% 7.1% 9.5% All-FTN-DFT-OFDM 7.1% 10.7% 14.2%

[0142] Additional Tx side operations may enhance the channel estimation accuracy for FTN based slot structures (e.g., all-FTN-DFT-S-OFDM and mixed-FTN-DFT-S-OFDM). Two of such operations can be summarized as follows that can be utilized individually or together.

[0143] Time windowing on immediate FTN OFDM symbols (relative to RS symbols) may mitigate impact of FTN-ISI. This operation could add soft edges to adjacent FTN-OFDM symbol with RS symbols. The shape of the window (or edge) in time domain determines the FDSS (as explained in an embodiment-FIG. 6) with different tradeoffs between the width of the main lobe and suppression of the side lobes. With time-windowing (or equivalently FDSS) on some of FTN-symbols, FTN-ISI can be surpassed for RS symbols.

[0144] For instance, for mixed-FTN-DFT-S-OFDM slot structure, 3.sup.rd and 10.sup.th symbols (FTN) could be time windowed as illustrated in FIG. 12. This can reduce inter-slot interference further. Another variation of this example could be applying time-windowing on none-FTN symbols of second and 11.sup.th leading to limit any residual FTN (e.g., from symbol 3-10).

[0145] FIG. 12 illustrates examples of time-windowing of edge FTN symbols 1200 with index 3 and 10 for mixed-FTN-DFT-S-OFDM slot structure according to embodiments of the present disclosure. An embodiment of the time-windowing of edge FTN symbols 1200 shown in FIG. 12 is for illustration only.

[0146] For all-FTN-DFT-S-OFDM slot structure example, 2.sup.nd, 4.sup.th, 9.sup.th, and 11.sup.th FTN symbols of slot could be time windowed as illustrated in FIG. 13.

[0147] FIG. 13 illustrates examples of time-windowing of adjacent FTN symbols 1300 with index 2, 4, 9 and 11 for all-FTN-DFT-S-OFDM slot structure according to embodiments of the present disclosure. An embodiment of the time-windowing of adjacent FTN symbols 1300 shown in FIG. 13 is for illustration only.

[0148] TX may cancel any incurred FTN-ISI on RS symbols by pre-equalizing RS symbols. RS symbols are intentionally varied from the original values; but as RS symbols are none-FTN symbols, the overall received RS symbols by Rx could be FTN-ISI free. Received symbols may be noisy and with channel-induced ISI version of original RS symbols. As the main ISI component in the observations, is estimated and equalized using the classical channel estimation techniques. The pre-coded/equalized RS symbols are generated based on set of FTN symbols by performing a matrix operation with a pre-equalization matrix that is dependent on FDSS utilized for FTN symbols, FTN compression rate and relative distance of FTN symbols with RS symbols.

[0149] Second variation of the embodiment is based on zero padding operation is drawn in FIG. 14 and an example of corresponding signal processing bock diagram is shown in FIG. 15. Compared to first embodiment, operations of 601 and 602 are modified.

[0150] FIG. 14 illustrates a flowchart of a method 1400 for variation of FTN-DFT-S-OFDM to generate FTN based DFT-S-OFDM based on zero padding operation according to embodiments of the present disclosure. The method 1400 as may be performed by a UE (e.g., 111-116 as illustrated in FIG. 1). An embodiment of the method 1400 shown in FIG. 14 is for illustration only. One or more of the components illustrated in FIG. 14 can be implemented in specialized circuitry configured to perform the noted functions or one or more of the components can be implemented by one or more processors executing instructions to perform the noted functions.

[0151] FIG. 15 illustrates examples of variation of Tx architecture of FTN-DFT-S-OFDM 1500 based on zero padding operation according to embodiments of the present disclosure. An embodiment of the variation of Tx architecture of FTN-DFT-S-OFDM 1500 shown in FIG. 15 is for illustration only.

[0152] The Q modulation data symbols are appended (padded) with (b1).sub.Q zeros, and the bQ symbols are DFT spread at operation 1401.

[0153] At operation 1402, the DFT outputs are down-sampled by the factor of bQ/M and M symbols are passed to the FDSS.

[0154] At operation 1403, the frequency domain spectrum shaping can be applied on the M DFT outputs and can be mapped to the sub-carriers corresponding to the assigned transmission bandwidth as an input of IFFT.

[0155] At operation 1404, based on the resultant M FDSS output, IFFT is generating FTN signal with compression rate of M/Q.

[0156] A UE (e.g., 111-116 as illustrated in FIG. 1) may up-sample or zero-pad the data modulation symbols to generate FTN based DFT-S-OFDM signal.

[0157] Third variation of the embodiment is based on distributed subcarrier mapping and its operations and block diagram are shown in FIG. 16 and FIG. 17, respectively. Compared to first embodiment, operation 1404 is modified.

[0158] FIG. 16 illustrates a flowchart of a method 1600 for variation of FTN-DFT-S-OFDM to generate FTN based DFT-S-OFDM based on distributed subcarrier mapping according to embodiments of the present disclosure. The method 1600 as may be performed by a UE (e.g., 111-116 as illustrated in FIG. 1). An embodiment of the method 1600 shown in FIG. 16 is for illustration only. One or more of the components illustrated in FIG. 16 can be implemented in specialized circuitry configured to perform the noted functions or one or more of the components can be implemented by one or more processors executing instructions to perform the noted functions.

[0159] FIG. 17 illustrates examples of variation of Tx architecture of FTN-DFT-S-OFDM 1700 based on distributed subcarrier mapping according to embodiments of the present disclosure. An embodiment of the variation of Tx architecture of FTN-DFT-S-OFDM 1700 shown in FIG. 17 is for illustration only.

[0160] The M DFT outputs are allocated over the entire bandwidth with equidistance between occupied sub-carriers (every (N/M).sup.th subcarriers/IFFT input) and zeros occupying unused subcarrier positions. The number of subcarriers of Tx/UE (M) could be assumed to be divisor of the number of the overall available subcarriers (N). Where the ratio of

[00031]$B{W}_{exp}=\frac{N}{M},$

is the bandwidth expansion factor.

[0161] At the transmitter, at operation 1604, each data symbol is spread over the allocated subcarriers which are scattered over the entire spectrum.

[0162] Output of IFFT can be modeled as single carrier transmission with time-domain compressed pulse shape of DFT-S-OFDM g(n) with ratio of 1/BW.sub.exp and symbols are sent every M/bQ samples, as follows:

[00032]$x\left(n\right)=\frac{1}{bQ}{.Math.}_{q=0}^{Q-1}{s}_q.g\left(B{W}_{exp}\left(n-q\frac{M}{bQ}\right)\right)\mathrm{where}g\left(n\right)={.Math.}_{k=0}^{M-1}{e}^{jn\frac{2k}{N}}.$

[0163] Time symbols out of the IFFT are FTN version of a repetition of the original symbols into the DFT with a scaling factor of 1/BW.sub.exp and some possible phase rotation, leading to FTN compression rate of M/Q.

[0164] Fourth variation of the embodiment is selecting any M consecutive DFT outputs (rather than first M DFT output) at operation 602. This may truncate different part of data spectrum and may impact on SER and PAPR levels. Compared to first embodiment, operation 602 is modified.

[0165] Fifth variation of the embodiment is based on subcarrier mapping and selecting different consecutive M inputs of IFFT (rather than first M inputs of IFFT) with zeros occupying unused subcarrier positions, which may cause some possible phase rotation on output signal. Compared to first embodiment, operation 604 is modified.

[0166] Instantaneous PAPR complementary cumulative distribution functions (CCDF) of FTN-DFT-S-OFDM

[00033]$\left(\mathrm{for}=\frac{12}{13},\frac{8}{9},\frac{6}{7}\right)$

and DFT-s-OFDM without any FDSS is shown in FIG. 18 (under QPSK modulation when 6 RB is utilized). FTN-DFT-S-OFDM, for FTN compression rates of 12/13, 8/9 and 6/7 achieves about 1 dB, 1.25 dB and 1.5 dB PAPR gains respectively compared with DFT-s-OFDM at 10.sup.3 CCDF level.

[0167] FIG. 18 illustrates an example of instantaneous PAPR CCDFs 1800 for QPSK/6RB without FDSS for FTN-DFT-S-OFDM and DFT-S-OFDM according to embodiments of the present disclosure. An embodiment of the instantaneous PAPR CCDFs 1800 shown in FIG. 18 is for illustration only.

[0168] FIG. 19 illustrates a flowchart of a method 1900 for according to embodiments of the present disclosure. The method 1100 as may be performed by a UE (e.g., 111-116 as illustrated in FIG. 1). An embodiment of the method 1900 shown in FIG. 19 is for illustration only. One or more of the components illustrated in FIG. 19 can be implemented in specialized circuitry configured to perform the noted functions or one or more of the components can be implemented by one or more processors executing instructions to perform the noted functions.

[0169] As illustrated in FIG. 19, the method 1900 begins at step 1904. In step 1904, the UE generates data modulation symbols including a set of zero symbols, wherein the data modulation symbols are up-sampled or zero-padded.

[0170] In step 1906, the UE performs, to obtain DFT output signal, a DFT spread operation on the up-sampled data modulation symbols or the zero-padded data modulation symbols.

[0171] In step 1908, the UE performs, based on (i) a target FTN compression rate and (ii) a SC allocation, a discarding operation or a down sampling operation on the DFT output signal, wherein the discarding operation or the down sampling operation generates a subset of DFT symbols.

[0172] In step 1910, the UE maps the subset of DFT symbols to a set of SCs corresponding to a transmission bandwidth.

[0173] In step 1912, the UE performs an IFFT operation on the subset of DFT symbols to obtain an FTN-DFT-S-OFDM signal, wherein the FTN-DFT-S-OFDM signal includes the target FTN compression rate comprising a positive rational number smaller than one.

[0174] In one embodiment, the FTN-DFT-S-OFDM signal includes an OFDM symbol time, a number of sub-carriers, and a number of OFDM symbols per slot; the FTN-DFT-S-OFDM signal is transmitted or received over a mixed-FTN-DFT-S-OFDM slot that includes time divisions of FTN data symbols, none-FTN data symbols, and none-FTN reference signal (RS) symbols that are placed within a slot; and the FTN-DFT-S-OFDM signal is transmitted or received over an all-FTN-DFT-S-OFDM slot that includes the time divisions of FTN data symbols and none-FTN RS symbols that are placed within the slot.

[0175] In one embodiment, the UE performs an FDSS operation on the subset of DFT symbols.

[0176] In one embodiment, the UE spreads each of the data modulation symbols over the set of subcarriers that is scattered over an entire spectrum.

[0177] In one embodiment, the UE spreads the data modulation symbols using the DFT spread operation and obtain consecutive DFT output signals.

[0178] In one embodiment, the UE spreads the data modulation symbols using the DFT spread operation and obtain different consecutive DFT output signals and performs the IFFT operation to the different consecutive DFT output signals to obtain the FTN-DFT-S-OFDM signal, the IFFT operation including a set of zeros occupying unused subcarrier positions.

[0179] In one embodiment, the UE enables an FTN-ISI pre-canceling operation using a time windowing operation or a pre-equalization/pre-coding of RS symbols; and adds soft edges to adjacent FTN-OFDM symbols with the RS symbols for the time windowing operation.

[0180] In one embodiment, the UE calculates the FTN compression rate based on a number of DFT output signals and a maximum number of symbols for the FTN-DFT-S-OFDM signal.

[0181] The above flowcharts illustrate example methods that can be implemented in accordance with the principles of the present disclosure and various changes could be made to the methods illustrated in the flowcharts herein. For example, while shown as a series of steps, various steps in each figure could overlap, occur in parallel, occur in a different order, or occur multiple times. In another example, steps may be omitted or replaced by other steps.

[0182] Although the present disclosure has been described with exemplary embodiments, various changes and modifications may be suggested to one skilled in the art. It is intended that the present disclosure encompass such changes and modifications as fall within the scope of the appended claims. None of the description in this application should be read as implying that any particular element, step, or function is an essential element that must be included in the claims scope. The scope of patented subject matter is defined by the claims.