Method and apparatus for synchronization

Abstract

The present disclosure relates to a 5G communication system or a 6G communication system for supporting higher data rates beyond a 4G communication system such as long term evolution (LTE). The communication methods and base station and UE implementations proposed in this disclosure implement new methods of PSS generation, in which predetermined M-sequences defined by predetermined polynomials and shifts are used, and new methods of spacing SS / PBCH transmissions of different existing radio access technologies (RATs) simultaneously supported in a network in the frequency and / or time domain.

Description

METHOD AND APPARATUS FOR SYNCHRONIZATION

[0001] The present disclosure relates to a method and an apparatus for synchronization in wireless communication system, and more particularly to a method and apparatus for transmitting or receiving a synchronization signal included in a synchronization signal (SS) / physical broadcast channel (PBCH) block.

[0002] Considering the development of wireless communication from generation to generation, the technologies have been developed mainly for services targeting humans, such as voice calls, multimedia services, and data services. Following the commercialization of 5G (5th-generation) communication systems, it is expected that the number of connected devices will exponentially grow. Increasingly, these will be connected to communication networks. Examples of connected things may include vehicles, robots, drones, home appliances, displays, smart sensors connected to various infrastructures, construction machines, and factory equipment. Mobile devices are expected to evolve in various form-factors, such as augmented reality glasses, virtual reality headsets, and hologram devices. In order to provide various services by connecting hundreds of billions of devices and things in the 6G (6th-generation) era, there have been ongoing efforts to develop improved 6G communication systems. For these reasons, 6G communication systems are referred to as beyond-5G systems.

[0003] 6G communication systems, which are expected to be commercialized around 2030, will have a peak data rate of tera (1,000 giga)-level bps and a radio latency less than 100μsec, and thus will be 50 times as fast as 5G communication systems and have the 1 / 10 radio latency thereof.

[0004] In order to accomplish such a high data rate and an ultra-low latency, it has been considered to implement 6G communication systems in a terahertz band (for example, 95GHz to 3THz bands). It is expected that, due to severer path loss and atmospheric absorption in the terahertz bands than those in mmWave bands introduced in 5G, technologies capable of securing the signal transmission distance (that is, coverage) will become more crucial. It is necessary to develop, as major technologies for securing the coverage, radio frequency (RF) elements, antennas, novel waveforms having a better coverage than orthogonal frequency division multiplexing (OFDM), beamforming and massive multiple input multiple output (MIMO), full dimensional MIMO (FD-MIMO), array antennas, and multiantenna transmission technologies such as large-scale antennas. In addition, there has been ongoing discussion on new technologies for improving the coverage of terahertz-band signals, such as metamaterial-based lenses and antennas, orbital angular momentum (OAM), and reconfigurable intelligent surface (RIS).

[0005] Moreover, in order to improve the spectral efficiency and the overall network performances, the following technologies have been developed for 6G communication systems: a full-duplex technology for enabling an uplink transmission and a downlink transmission to simultaneously use the same frequency resource at the same time; a network technology for utilizing satellites, high-altitude platform stations (HAPS), and the like in an integrated manner; an improved network structure for supporting mobile base stations and the like and enabling network operation optimization and automation and the like; a dynamic spectrum sharing technology via collision avoidance based on a prediction of spectrum usage; an use of artificial intelligence (AI) in wireless communication for improvement of overall network operation by utilizing AI from a designing phase for developing 6G and internalizing end-to-end AI support functions; and a next-generation distributed computing technology for overcoming the limit of UE computing ability through reachable super-high-performance communication and computing resources (such as mobile edge computing (MEC), clouds, and the like) over the network. In addition, through designing new protocols to be used in 6G communication systems, developing mechanisms for implementing a hardware-based security environment and safe use of data, and developing technologies for maintaining privacy, attempts to strengthen the connectivity between devices, optimize the network, promote softwarization of network entities, and increase the openness of wireless communications are continuing.

[0006] It is expected that research and development of 6G communication systems in hyper-connectivity, including person to machine (P2M) as well as machine to machine (M2M), will allow the next hyper-connected experience. Particularly, it is expected that services such as truly immersive extended reality (XR), high-fidelity mobile hologram, and digital replica could be provided through 6G communication systems. In addition, services such as remote surgery for security and reliability enhancement, industrial automation, and emergency response will be provided through the 6G communication system such that the technologies could be applied in various fields such as industry, medical care, automobiles, and home appliances.

[0007] It is assumed that the 6th Generation (6G) communications system currently under development will have to coexist with previous generations of communications systems (e.g., 4G LTE or 5G NR) for some time. Such coexistence of two or more RATs may be achieved byre-farmingthe frequency spectrum, in which each RAT is allocated its own separate frequency subband, or bydynamic spectrum sharingbetween different RATs. With such a coexistence it is necessary to ensure a minimum cross-correlation between SS / PBCH blocks used in 6G communication networks and SS / PBCH blocks used in communication networks of a previous RAT (e.g., 5G NR) to minimize the possibility of erroneous synchronization between the UE and the TRP of not supported RAT, which may occur when, for example, 5G NR capable UE tries to synchronize with 6G communication network or 6G capable UE tries to synchronize with 5G NR communication network, etc.

[0008] The communication methods and TRP and UE implementations proposed in this disclosure implement new methods of PSS generation, in which predetermined M-sequences defined by predetermined polynomials and shifts are used, and new methods of spacing SS / PBCH transmissions of different existing radio access technologies (RATs) simultaneously supported in a network in the frequency and / or time domain.

[0009] The main technical result of the present invention consists in minimizing the cross correlation of SS / PBCH blocks of different RATs and enabling the coexistence of different RATs in the same network.

[0010] Fig. 1 illustrates a flowchart of TRP-implemented method of communication with the UE according to the first aspect of the present disclosure.

[0011] Fig. 2 illustrates a non-limiting example of SS / PBCH block structure that may be generated and used in the technical solution according to the present disclosure to synchronize UE with TRP or with a communication network cell provided by the TRP.

[0012] Fig. 3 illustrates a non-limiting example of a possible arrangement of 6G SS / PBCH blocks in a time domain, taking into account the presence of 5G NR SS / PBCH blocks in said time domain, which may be applied in the technical solution according to the present disclosure.

[0013] Fig. 4 illustrates a non-limiting example of a possible arrangement of 6G SS / PBCH blocks in a frequency domain, taking into account the presence of 5G NR SS / PBCH blocks in said frequency domain, which may be applied in the technical solution according to the present disclosure.

[0014] Fig. 5 illustrates a flowchart of generating the PSS to be included into the SS of the SS / PBCH block according to the first embodiment of PSS generation in the present disclosure.

[0015] Fig. 6 illustrates ambiguity functions for each of PSS candidates generated according to the first embodiment of PSS generation in the present disclosure as illustrated in Fig. 5.

[0016] Fig. 7 illustrates a flowchart of generating the PSS to be included into the SS of the SS / PBCH block according to the second embodiment of PSS generation in the present disclosure.

[0017] Fig. 8 illustrates ambiguity functions for each of PSS candidates generated according to the second embodiment of PSS generation in the present disclosure as illustrated in Fig. 7.

[0018] Fig. 9 illustrates possible mutual arrangements of 5G SS / PBCH and 6G SS / PBCH in the frequency domain for a small communication system bandwidth (left side of the figure) and a large communication system bandwidth (right side of the figure).

[0019] Fig. 10 illustrates a schematic representation of the TRP according to the second aspect of the present disclosure, which is configured to perform the communication method according to the first aspect of the present disclosure.

[0020] Fig. 11 illustrates a flowchart of UE-implemented method of communication with the TRP according to the fourth aspect of the present disclosure.

[0021] Fig. 12 illustrates an exemplary scheme of detection of one or more SS / PBCH blocks emitted by the TRP to implement the procedure of UE accessing to the communication network provided by the TRP.

[0022] Fig. 13 illustrates a schematic representation of the UE according to the fifth aspect of the present disclosure, which is configured to perform the communication method according to the fourth aspect of the present disclosure.

[0023] Fig. 14 illustrates a schematic representation of a communication system according to the seventh aspect of the present disclosure.

[0024] Due to the present disclosure, the above and other problems, although not explicitly stated, but associated with the above-listed problems in the prior art, or arising from them, are solved or at least mitigation of the severity of these problems is achieved. The above and additional problems and the corresponding advantageous technical effects achieved will be further discussed in the following description in the context of the specific features of the technical solution proposed in the present application.

[0025] Proposed in a first aspect of the present disclosure is TRP-implemented method of communication with UE, the method includes the steps of: generating one or more SS / PBCH blocks, wherein a binary sequence of maximum length (M-sequence) is used in said generation to modulate a Primary Synchronization Signal (PSS) included in the SS of the SS / PBCH block; emitting the one or more generated SS / PBCH blocks, wherein each of the one or more generated SS / PBCH blocks is emitted on time and / or frequency resources different at least in part from those used by 5G NR communication system for emitting one or more SS / PBCH blocks; and receiving an uplink transmission from the UE that has performed a procedure for accessing a communication network served by said TRP based on the detected one or more SS / PBCH blocks.

[0026] In a possible example of the first aspect of the present disclosure, each of the one or more generated SS / PBCH blocks is emitted on Orthogonal Frequency Division Multiplexing (OFDM) symbols not used by the 5G NR communication system for emitting the one or more SS / PBCH blocks.

[0027] In a possible example of the first aspect of the present disclosure, each of the one or more generated SS / PBCH blocks is emitted in an unoccupied half of a frame, and the one or more SS / PBCH blocks used by the 5G NR communication system are emitted on OFDM symbols of the other half of the same frame.

[0028] In a possible example of the first aspect of the present disclosure, a synchronization channel raster according to which the one or more generated SS / PBCH blocks are emitted is positioned with a synchronization channel frequency offset relative to a synchronization channel raster according to which the one or more SS / PBCH blocks used in the 5G NR mobile communications are emitted, wherein the synchronization channel frequency offset is selected so as to provide partial overlap or complete absence of overlap in a frequency domain between each of the one or more generated SS / PBCH blocks and each of the one or more SS / PBCH blocks used by the 5G NR communication system.

[0029] In a possible example of the first aspect of the present disclosure, the synchronization channel frequency offset is greater than or equal to the half of the synchronization channel raster according to which the one or more SS / PBCH blocks used by the 5G NR communication system are emitted.

[0030] In a possible example of the first aspect of the present disclosure, the synchronization channel frequency offset is specified by an integer number of frequency intervals between adjacent subcarriers of each of the one or more generated SS / PBCH blocks.

[0031] In a possible example of the first aspect of the present disclosure, identifier is determined according to the equation , wherein said PSS signals value, and the secondary synchronization signal (SSS) included in the same SS of the SS / PBCH block as the PSS signals value.

[0032] In a possible example of the first aspect of the present disclosure, the PSS is generated by performing the following steps of: using a predetermined polynomial (multinomial), generating said M-sequence; performing a cyclic shift of the generated M-sequence according to value to be signaled by the PSS being generated; performing Binary Phase-Shift Keying (BPSK) modulation on the cyclically shifted M-sequence; mapping the modulated M-sequence to the subcarriers; and performing Cyclic Prefix OFDM (CP-OFDM) on the symbol sequence obtained by the mapping.

[0033] In a possible example of the first aspect of the present disclosure as the predetermined polynomial the following polynomial is used:x(i+ 7) = (x(i+ 6) +x(i+ 5) +x(i+ 4) +x(i)) mod 2 with initial state [x(6)x(5)x(4)x(3)x(2)x(1)x(0)] = [0011011], wherexis the binary M-sequence,iis the index of elementx(i) of the sequence, and mod 2 is the operation returning a remainder of an integer division by 2.

[0034] In a possible example of the first aspect of the present disclosure, the cyclically shifted M-sequence is obtained according to the equation , where m is the index of the element of the original (not shifted) M-sequence for obtaining the cyclically shifted M-sequence, n is a running index that is used to determine an element of the cyclically shifted M-sequence and a specific subcarrier to which this element of the M-sequence will be mapped after the modulation, , is a cyclic shift in bits, the specific value to be applied in one case or another is selected depending on the value , which is to be signaled in the one or other case by the PSS being generated, when =0, the value is determined to be 0, when =1, the value is determined to be 43, and when =2, the value is determined to be 85, and mod 127 is the operation returning a remainder of an integer division by 127.

[0035] In a possible example of the first aspect of the present disclosure, the PSS is generated by performing the following steps of: using the predetermined polynomial defined by the value , which is to be signaled by the PSS being generated, generating said M-sequence; performing cyclic extension of the generated M-sequence to a length equal to a power of 2; performing / 2-BPSK-based modulation on the cyclically extended M-sequence; performing spectrum spreading of the modulated M-sequence by a Discrete Fourier Transform (DFT); mapping the obtained modulated M-sequence having spectrum spread by the DFT onto subcarriers; and performing CP-OFDM on the symbol sequence obtained by the mapping.

[0036] In a possible example of the first aspect of the present disclosure, when the value = 0, as the predetermined polynomial the following polynomial is usedx(i+ 7) = (x(i+ 6) +x(i+ 5) +x(i+ 4) +x(i)) mod 2 with initial state [x(6)x(5)x(4)x(3)x(2)x(1)x(0)] = [1111110], when the value = 1, as the predetermined polynomial the following polynomial is usedx(i+ 7) = (x(i+ 3) +x(i)) mod 2 with initial state [x(6)x(5)x(4)x(3)x(2)x(1)x(0)] = [0010110], when the value = 2, as the predetermined polynomial the following polynomial is usedx(i+ 7) = (x(i+ 5) +x(i+ 3) +x(i+ 1) +x(i)) mod 2 with initial state [x(6)x(5)x(4)x(3)x(2)x(1)x(0)] = [1110011].

[0037] In a possible example of the first aspect of the present disclosure, said polynomials are selected according to the criterion of minimizing the cross-correlation between the generated PSS to be included in the SS of the generated SS / PBCH block and the PSS included in the SS of the SS / PBCH block used by the 5G NR communication system.

[0038] In a possible example of the first aspect of the present disclosure, the procedure for accessing the communication network served by said TRP comprises any of an initial access procedure, a handover procedure, a failure recovery procedure.

[0039] In a possible example of the first aspect of the present disclosure, the TRP is a Base Station (BS), Access Point (AP), or Node B (NodeB).

[0040] Provided in a second aspect of the present disclosure is the TRP (300) comprising a transmit-receive antenna unit and a processor configured to perform the method of the first aspect of the present disclosure or any possible example of the first aspect of the present disclosure.

[0041] Provided in a third aspect of the present disclosure is a storage medium storing processor executable instructions, which, when executed by the processor of a device equipped with a transmit-receive antenna unit, cause the method of the first aspect of the present disclosure or any possible example of the first aspect of the present disclosure to perform.

[0042] Provided in a fourth aspect of the present disclosure is the UE-implemented method of communication with the TRP, the method includes the steps of: performing a procedure for accessing a communication network served by said TRP, in which one or more SS / PBCH blocks emitted by the TRP are detected, wherein M-sequence is used to detect the PSS included in the SS of the one or more SS / PBCH blocks being detected; in response to completion of the procedure for accessing the communication network, performing an uplink transmission to the TRP, wherein each of the one or more SS / PBCH blocks is detected on time and / or frequency resources different at least in part from those used by 5G NR communication system for transmitting one or more SS / PBCH blocks.

[0043] In a possible example of the fourth aspect of the present disclosure, each of the one or more SS / PBCH blocks is detected on OFDM symbols not used by the 5G NR communication system for emitting the one or more SS / PBCH blocks.

[0044] In a possible example of the fourth aspect of the present disclosure, each of the one or more SS / PBCH blocks is detected in an unoccupied part (e.g. a frame half) of a frame, and the one or more SS / PBCH blocks used by the 5G NR communication system are emitted on OFDM symbols of another part of the same frame (e.g. the other frame half).

[0045] In a possible example of the fourth aspect of the present disclosure, a synchronization channel raster according to which the one or more SS / PBCH blocks are emitted is positioned with a synchronization channel frequency offset relative to a synchronization channel raster according to which the one or more SS / PBCH blocks used in the 5G NR mobile communications are emitted, wherein the synchronization channel frequency offset is selected so as to provide partial overlap or complete absence of overlap in a frequency domain between each of the one or more SS / PBCH blocks being detected and each of the one or more SS / PBCH blocks used by the 5G NR communication system.

[0046] In a possible example of the fourth aspect of the present disclosure, the synchronization channel frequency offset is greater than or equal to a half of the synchronization channel raster according to which the one or more SS / PBCH blocks used by the 5G NR communication system are emitted.

[0047] In a possible example of the fourth aspect of the present disclosure, the synchronization channel frequency offset is specified by an integer number of frequency intervals between adjacent subcarriers of each of the one or more SS / PBCH blocks being detected.

[0048] In a possible example of the fourth aspect of the present disclosure, the detection of the one or more SS / PBCH blocks emitted by the TRP comprises the following steps of: performing rough time and frequency synchronization with a cell, detecting the PSS signaling value, detecting the SSS signaling value, performing, based on the detected SSS, fine time and frequency synchronization with the cell, determining identifier of the cell, and detecting and decoding, based at least in part on the determined cell identifier, the PBCH, wherein performing the procedure for accessing the communication network further comprises the step of: detecting and decoding a System Information Block (SIB) emitted by the TRP.

[0049] In a possible example of the fourth aspect of the present disclosure, identifier is determined according to the equation .

[0050] In a possible example of the fourth aspect of the present disclosure, the PSS detection is performed on the basis of PSS candidates by performing matched filtering with the search for a frequency offset and value on the basis of maximum likelihood criterion, wherein predetermined polynomials and predetermined shifts are used at the UE to generate the PSS candidates.

[0051] In a possible example of the fourth aspect of the present disclosure, as the predetermined polynomial the following polynomial is used:x(i+ 7) = (x(i+ 6) +x(i+ 5) +x(i+ 4) +x(i)) mod 2 with initial state [x(6)x(5)x(4)x(3)x(2)x(1)x(0)] = [0011011], wherexis the binary M-sequence,iis the index of elementx(i) of the sequence, and mod 2 is the operation returning a remainder of an integer division by 2.

[0052] In a possible example of the fourth aspect of the present disclosure, as the predetermined shifts used are the cyclic shifts applied to the M-sequence used in generating the PSS candidates, wherein for a possible value = 0, the value of the predetermined cyclic shift is 0, for a possible value = 1, the value of the predetermined cyclic shift is 43, and for a possible value = 2, the value of the predetermined cyclic shift is 85.

[0053] In a possible example of the fourth aspect of the present disclosure, as the predetermined polynomial used are one or more of the following polynomials: for a possible value = 0, the polynomial of the formx(i+ 7) = (x(i+ 6) +x(i+ 5) +x(i+ 4) +x(i)) mod 2 with initial state [x(6)x(5)x(4)x(3)x(2)x(1)x(0)] = [1111110] is used, for a possible value = 1, the polynomial of the formx(i+ 7) = (x(i+ 3) +x(i)) mod 2 with initial state [x(6)x(5)x(4)x(3)x(2)x(1)x(0)] = [0010110] is used, for a possible value = 2, the polynomial of the formx(i+ 7) = (x(i+ 5) +x(i+ 3) +x(i+ 1) +x(i)) mod 2 with initial state [x(6)x(5)x(4)x(3)x(2)x(1)x(0)] = [1110011] is used.

[0054] In a possible example of the fourth aspect of the present disclosure, said polynomials are selected based on the criterion of minimizing the cross-correlation between the generated PSS included in the SS of the SS / PBCH block being detected and the PSS included in the SS of the SS / PBCH block used by the 5G NR communication system.

[0055] In a possible example of the fourth aspect of the present disclosure, the procedure for accessing the communication network served by said TRP comprises any of an initial access procedure, a handover procedure, a connection recovery procedure.

[0056] Provided in a fifth aspect of the present disclosure is the UE comprising a transmit-receive antenna unit and a processor configured to perform the method of the fourth aspect of the present disclosure or any possible example of the fourth aspect of the present disclosure.

[0057] Provided in a sixth aspect of the present disclosure is a storage medium storing processor executable instructions, which, when executed by the processor of a device equipped with a transmit-receive antenna unit, cause the method of the fourth aspect of the present disclosure or any possible example of the fourth aspect of the present disclosure to perform.

[0058] Provided in a seventh aspect of the present disclosure is a communication system comprising one or more TRPs according to the second aspect of the present disclosure or according to any possible example of the second aspect of the present disclosure, and one or more UEs according to the fifth aspect of the present disclosure or according to any possible example of the fifth aspect of the present disclosure.

[0059] According to the present disclosure, a synchronization signal included in a SS / PBCH block, is generated and / or emitted in a manner that minimizes the likelihood of synchronization errors between the UE and the transmit-receive point (TRP) in a communications network, in which a Radio Access Technology (RAT), e.g., 5th Generation New Radio (5G NR) communication technology, is used, not supported by the UE.

[0060] The procedure for accessing the network, of which the initial access procedure is a non-limiting example, allows the UE to establish a connection / communication with the network. To provide network access, TRPs deployed in the network generate SS / PBCH blocks and periodically transmit (emit) them for being detected by user terminals located in the service area of these TRPs. Successful detection and decoding of SS / PBCH blocks allows the UE to synchronize with the TRP and thereby gain access to the communication network.

[0061] The TRP may be, but not limited to, a base station (BS), an access point (AP), or a Node B.

[0062] It is assumed that the 6th Generation (6G) communications system currently under development will have to coexist with previous generations of communications systems (e.g., 4G LTE or 5G NR) for some time. Such coexistence of two or more RATs may be achieved byre-farmingthe frequency spectrum, in which each RAT is allocated its own separate frequency subband, or bydynamic spectrum sharingbetween different RATs. With such a coexistence it is necessary to ensure a minimum cross-correlation between SS / PBCH blocks used in 6G communication networks and SS / PBCH blocks used in communication networks of a previous RAT (e.g., 5G NR) to minimize the possibility of erroneous synchronization between the UE and the TRP of not supported RAT, which may occur when, for example, 5G NR capable UE tries to synchronize with 6G communication network or 6G capable UE tries to synchronize with 5G NR communication network, etc.

[0063] Thus, the technology disclosed in this application solves the problem of ensuring, with the coexistence of 6G and previous communication technology (for example, 5G NR), minimal cross-correlation between the SS / PBCH blocks used in 6G communication networks and the SS / PBCH blocks used in communication networks of previous RAT to minimize the likelihood of UE synchronization errors.

[0064] Fig. 1illustrates a flowchart of TRP-implemented method of communication with the UE according to the first aspect of the present disclosure.

[0065] For communication between the TRP and the UE any available (operating) frequency range may be used, including the one currently used for 4G LTE, Pre- 5G, 5G NR, etc. Non-limiting examples of the available frequency range may include Frequency Range 1 (FR1) up to 7.125 GHz or at least a portion thereof, Frequency Range 2 (FR2) from 24.25 GHz to 71 GHz or at least a portion thereof, or the frequency range from 7.125 GHz to 24.25 GHz or at least a portion thereof.

[0066] The method begins and proceeds to step S100, in which one or more SS / PBCH blocks are generated, wherein the binary M-sequence is used in said generation to modulate the PSS included in the SS of the SS / PBCH block. The term "SS / PBCH block" refers to the arrangement of the SS and the PBCH into a unit of transmitted information. In some cases, the abbreviations 'PSS' and 'SS' may be used interchangeably in this detailed description. Periodic transmission of SS / PBCH blocks allows the UE to establish communication with the network based on information that may be determined by the UE from the contents of the SS / PBCH block. Such information may include, but is not limited to, the cell physical identifier , System Frame Number (SFN), System Information (SI), Master Information Block (MIB), reference signal (Reference Signal, RS), based on which the UE may make various cell measurements, such as, but not limited to, Reference Signal Received Power (RSRP), Reference Signal Received Quality (RSRQ), etc.

[0067] A non-limiting example of SS / PBCH block structure that may be generated in step S100 is illustrated in Fig. 2. As shown in Fig.2 SS / PBCH block consists of the SS and the PBCH. The entire block occupies 240 subcarriers in the frequency domain and 4 OFDM symbols in the time domain. In this case, the SS consists of the PSS and the SSS, each of which is mapped to 127 center subcarriers in the zero (leftmost) and second OFDM symbols, respectively. The PBCH is mapped to all 240 subcarriers in the first and third OFDM symbols, wherein in the second OFDM symbol the PBCH is mapped to the outermost 48 subcarriers on each side of the SSS. In the second OFDM symbol, guard bands may be used between the SSS and the PBCH.

[0068] The PSS signals the value and is used for coarse time and frequency synchronization with a cell. SSS signals the value and is used for finer time and frequency synchronization with the cell. and values representing portions of the cell identification information are required for the UE to determine, in the process of synchronization with the cell, the cell to which the UE has to couple to access the communication network. For a particular cell, a particular value, from which the values of and parameters may be derived, may be preset, for example, by a communication network operator. In a non-limiting and variables may be derived from the value as follows: =mod( , 3), =floor( / 3). The cell identifier is determinable according to the equation . The three possible values used may respectively be signaled by three (different) PSS candidates, each of which, in general, represents the M-sequence cyclically shifted in one or another case according to one of the three predetermined cyclic shift values, which will be described in detail below.

[0069] SSS is typically represented by 336 SSS sequences based on Gold codes, and the PBCH carrying SI and / or MIB is typically represented by polar code modulated based on Quadrature Phase-Shift Keying (QPSK), with Demodulation Reference Signals (DMRS) evenly distributed in it (with a certain step). The general exemplary SS / PBCH block structure illustrated in Fig. 2 may generally be consistent with that used in 5G NR, and it may equally be applied in an embodiment of the technical solution proposed in the present disclosure to implement corresponding functions in mobile communications of a next RAT, such as 6th Generation (6G) mobile communications. In other words, if the PSS is generated as shown and described in detail with reference at least to Figs. 5 and 7, it will still be mapped to 127 center subcarriers and located on the leftmost OFDM symbol as illustratively shown in Fig. 2.

[0070] The present application relates mainly to (i) improved methods of PSS generation and / or (ii) new methods for arranging and transmitting SS / PBCH blocks of a single RAT (e.g., 6G) in the frequency and / or time domain when in this frequency and / or time domain SS / PBCH blocks of another RAT (e.g., 5G NR) are used simultaneously, each of the methods contributes to the ability of user terminals supporting different RATs to unambiguously distinguish between SS / PBCH blocks of these different RATs. It is clear that minimal cross-correlation between SS / PBCH blocks of different RATs will be achieved by using both (i) and (ii) simultaneously. However, it should be clear that combining the proposed methods (i) and (ii) into a single technical solution is not mandatory. In some alternative embodiments, only (i) may be performed, and arrangement and transmission of SS / PBCH blocks in the frequency and / or time domain may be fulfilled by any methods known in the art, for example, methods provided for these purposes in 5G NR specifications. And conversely, in some other alternative embodiments, only (ii) may be performed, and generation of SS / PBCH may be fulfilled by any method known in the art, for example, the method provided for these purpose in 5G NR specifications. It is clear that these alternative embodiments will be inferior to the main embodiment, which uses both (i) and (ii), in terms of performance, i.e. by the value of cross-correlation between the SS / PBCH blocks of different RATs, but the values of correlation between the SS / PBCH blocks of different RATs in these alternative embodiments will still be sufficient to successfully distinguish between the SS / PBCH blocks of different RATs.

[0071] The flowchart of generation of the PSS for the inclusion into the SS of the SS / PBCH block according to the first embodiment of PSS generation in the present disclosure will be described next with reference to Fig. 5 and Fig. 6. As shown in Fig. 5, the PSS generation begins by executing step S100.1, in which M-sequence is generated using a predetermined polynomial. The M-sequence, as is known, is a pseudo-random binary sequence generated by a linear-feedback shift register and having a maximum period. The M-sequence is linear recurrent over the Galois field of order 2 (GF(2)). M-sequences have good autocorrelation and cross-correlation properties, which makes it possible to effectively separate signals and detect them even in conditions of strong interference.

[0072] The predetermined polynomial that may be used at step S100.1 is the polynomial of the following form:x(i+ 7) = (x(i+ 6) +x(i+ 5) +x(i+ 4) +x(i)) mod 2 with initial state [x(6)x(5)x(4)x(3)x(2)x(1)x(0)] = [0011011], wherexis the binary M-sequence,iis the index of elementx(i) of the sequence, and mod 2 is the operation returning a remainder of an integer division by 2. The specified polynomial was selected by the authors of the present disclosure by brute-force checking various possible primitive polynomials and comparing them on the basis of the criterion of minimizing cross-correlation between the PSS generated by each of the compared polynomials and the PSS used in 5G NR. The above-specified polynomial provided the minimum cross-correlation of PSSs of different RATs in the presence between them of various shifts in the time-frequency domain. Further explanations in this regard will be given below with reference to Fig. 6.

[0073] Upon execution of step S100.1, the PSS generation proceeds to executing step S100.3, in which the generated M-sequence is cyclically shifted according to value to be signaled by the PSS being generated. The cyclically shifted M-sequence is obtained, when executing this step S100.3, according to the equation , where m is the index of an element of the original (not shifted) M-sequence for obtaining the cyclically shifted M-sequence, n is a running index with which an element of the cyclically shifted M-sequence and a specific subcarrier to which this element of the M-sequence will be mapped after the modulation are determined, , is a cyclic shift in bits, mod 127 is the operation returning a remainder from an integer division by 127. The specific value to be applied is selected depending on the value to be signaled by the generated PSS. In the technical solution proposed in this disclosure: for signaling the value = 0 in the PSS being generated, the value is predetermined to be 0 bits (i.e. zero cyclic shift), for signaling the value = 1 in the PSS being generated, the value is predetermined to be 43 bits (i.e. cyclic shift of the sequence by 43 bits), for signaling the value = 2 in the PSS being generated, the value is predetermined to be 85 bits (i.e. cyclic shift of the sequence by 85 bits). The indicated specific values of the cyclic shift were selected by the authors empirically as the values that make the maximum contribution to minimization of cross-correlation between PSSs of different RATs, signaling a same value .

[0074] Upon execution of step S100.3, the PSS generation proceeds to execution of step S100.5, in which BPSK-based modulation is performed on the cyclically shifted M-sequence according to , step S100.7, in which the modulated M-sequence is mapped to the subcarriers according to the SS / PBCH block structure, for example, according to the SS / PBCH block structure shown in Fig. 2, and step S100.9, in which CP-OFDM (Cyclic Prefix OFDM) is performed on the symbol sequence obtained by the mapping. Steps S100.3, S100.7, S100.9 may be implemented by any methods known in the art. Since it is known in the art how BPSK-based modulation may be implemented as such, how mapping of a sequence onto subcarriers may be implemented as such, and how CP-OFDM on the mapped sequence may be implemented as such, detailed descriptions of operations performed at steps S100.5, S100.7, S100.9 are not given herein for the purpose of clear and detailed description of namely the technical contribution of the present disclosure to the prior art.

[0075] As the result of executing steps S100.1, S100.3, S100.5, S100.7, and S100.9 according to the first embodiment of PSS generation in the present disclosure, the first variant of the PSS code / structure may be obtained, to be included in the SS of the SS / PBCH block. Thus, for different values by the above-described first embodiment of PSS generation, up to three different PSS variants may be obtained by using in step S100.1 the M-sequence defined by said predetermined polynomial and applying in step S100.3 different values of cyclic shifts for different signaled values.

[0076] Illustrated in Fig. 6 are ambiguity functions for each of the possible, based on values, PSS variants generated according to the first embodiment of PSS generation as described above with reference to Fig. 5. In general, one may notice that the ambiguity function of any one of the possible generated PSS variants (for each of ) is sufficiently localized (definite), i.e. when a small frequency and / or time shift appears, the ambiguity function drops sharply and demonstrates 5G NR-comparable energy efficiency as evidenced by the Peak-to-Average Power Ratio (PAPR) and Cubic Metric (CM). Thanks to this, frequency shifts and timing on the UE side, i.e. the start boundaries of PSS transmissions in SS / PBCH blocks can be detected precisely. Based on the characteristics and properties of the obtained ambiguity functions, a matched filter to be used at the UE or TRP may be implemented as software and / or hardware.

[0077] In other words, the use of the PSS generation method disclosed with reference to Fig. 5 provides PSS code / structure that minimizes cross-correlation between SS / PBCH blocks of different RATs, i.e. minimizes the likelihood of erroneous detection at the UE of PSS that is not supported by said UE. Therefore, the disclosed technology of generating PSS for the inclusion into SS / PBCH block allows to reduce the likelihood of 6G PSS being erroneously detected by UE supporting 5G NR, and reduce the likelihood of 5G NR PSS being erroneously detected by UE supporting 6G. In support of the above, the inventors of the present disclosure calculated the values of cross-correlation of PSSs generated according to Fig. 5 among themselves and relative to PSSs used in 5G NR, and summarized the results in the following Table 1.

[0078] Table 1 -Values of cross-correlation of PSSs generated according to Fig. 5 among themselves and relative to 5G NR PSSs (average cross-correlation value between different PSSs is 0.2031)

[0079]

[0080] The flowchart of generation of the PSS for the inclusion into the SS of the SS / PBCH block according to the second embodiment of PSS generation in the present disclosure will be described next with reference to Fig. 7 and Fig. 8. As shown in Fig. 7, the PSS generation begins by executing step S100.2, in which M-sequence is generated using the predetermined polynomial defined by value , which is to be signaled by the PSS being generated. Particularly, when the value = 0 is subject to signaling by the PSS being generated, as the predetermined polynomial, the polynomial of the following form is usedx(i+ 7) = (x(i+ 6) +x(i+ 5) +x(i+ 4) +x(i)) mod 2 with initial state [x(6)x(5)x(4)x(3)x(2)x(1)x(0)] = [1111110], when the value = 1 is subject to signaling by the PSS being generated, as the predetermined polynomial the polynomial of the following form is usedx(i+ 7) = (x(i+ 3) +x(i)) mod 2 with initial state [x(6)x(5)x(4)x(3)x(2)x(1)x(0)] = [0010110], when the value = 2 is subject to signaling by the PSS being generated, as the predetermined polynomial the polynomial of the following form is usedx(i+ 7) = (x(i+ 5) +x(i+ 3) +x(i+ 1) +x(i)) mod 2 with initial state [x(6)x(5)x(4)x(3)x(2)x(1)x(0)] = [1110011].

[0081] Upon execution of step S100.2, the PSS generation proceeds to execution of step S100.4, in which the generated M-sequence having, in the preferred embodiment, the size of 127 subcarriers is cyclically extended to a length equal to a power of 2 (for example, but not limited to mentioned value, to the size of 128 subcarriers). Since in the subsequent step S100.8 (which will be described below) it is desired to have the sequence of the length equal to a power of 2, the cyclic extension, performed at step S100.2, of the generated M-sequence to the length equal to a power of 2 allows step S100.8 to be performed in a computationally efficient manner. In a non-limiting example, step S100.4 may be implemented by copying a first bit of the sequence to the end of the sequence.

[0082] Upon execution of step S100.4, the PSS generation proceeds to execution of step S100.6, in which the cyclically extended M-sequence is modulated based on / 2-shifted BPSK ( / 2-BPSK). It is known from the prior art how / 2-BPSK modulation as such may be implemented, so detailed description of the operation performed at this step is not given here.

[0083] Upon execution of step S100.6, the PSS generation proceeds to execution of step S100.8, in which the spectrum of the modulated M-sequence is spread by Discrete Fourier Transform (DFT-spreading). Spreading the sequence spectrum with DFT in combination with OFDM (referred to and also known as "DFT-s-OFDM" for short) allows the generation of energy efficient signals (i.e. signals having low PAPR / CM values). The use of DFT-s-OFDM operations as such is known from the prior art (see, for example, section 6.3.1.4 of 5G NR-related specification 3GPP TR 38.211, where these operations as such correspond to "Transform Precoding").

[0084] Upon execution of step S100.8, the PSS generation proceeds to executing step S100.10, in which the obtained modulated M-sequence with DFT-spread spectrum is mapped, according to the SS / PBCH block structure, e.g. according to the SS / PBCH block structure shown in Fig. 2, to subcarriers, and step S100.12, in which CP-OFDM is performed on the symbol sequence obtained by the mapping. Steps S100.10, S100.12 may be implemented by any methods known in the art. Since it is known in the prior art how mapping of a sequence to subcarriers may be implemented as such, and how CP-OFDM on the sequence obtained by the mapping may be implemented as such, the detailed description of steps S100.10, S100.12 is not given here.

[0085] As the result of executing steps S100.2, S100.4, S100.6, S100.8, S100.10, and S100.12 according to the second embodiment of PSS generation in the present disclosure, the second variant of the PSS code / structure may be obtained, to be included in the SS of the SS / PBCH block. Therefore, for different values by the above-described second embodiment of PSS generation, up to three different PSS variants may be obtained by using in step S100.2 the M-sequence defined by a polynomial of the three predetermined polynomials.

[0086] Illustrated in Fig. 8 are ambiguity functions for each of the possible, based on values, PSS variants generated according to the second embodiment of PSS generation as described above with reference to Fig. 7. All the ambiguity functions of the three generated PSS variants are sufficiently localized and demonstrate energy efficiency comparable to 5G NR, as evidenced by the PAPR and CM. Due to this, frequency shifts and timing, i.e. the start boundaries of PSS transmissions in SS / PBCH blocks, can be precisely detected at the UE side. Based on the characteristics and properties of the obtained ambiguity functions, a matched filter to be used at the UE or TRP may be implemented as software and / or hardware.

[0087] In other words, the use of the PSS generation method disclosed with reference to Fig. 7 provides PSS code / structure that minimizes cross-correlation between SS / PBCH blocks of different RATs, i.e. minimizes the likelihood of erroneous detection by the UE of PSS that is not supported by said UE. Therefore, the disclosed technology of generating PSS for the inclusion into SS / PBCH block allows to reduce the likelihood of 6G PSS being erroneously detected by UE supporting 5G NR, and reduce the likelihood of 5G NR PSS being erroneously detected by UE supporting 6G. In support of the above, the inventors of the present disclosure calculated the values of cross-correlation of PSSs generated according to Fig. 7 among themselves and relative to PSSs used in 5G NR, and summarized the results in the following Table 2.

[0088] Table 2 -Values of cross-correlation of PSSs generated according to Fig. 7 among themselves and relative to 5G NR PSSs (average cross-correlation value between different PSSs is 0.2124)

[0089]

[0090] Returning to Fig. 1, upon execution of step S100, the method proceeds to step S110, in which the one or more generated SS / PBCH blocks are broadcasted. The main feature of this step is that the broadcasting of each of the one or more generated SS / PBCH blocks is carried out on time and / or frequency resources that differ, at least in part, from those used for broadcasting one or more SS / PBCH blocks in 5G NR communication system. The fact that the time and / or frequency resources of some SS / PBCH blocks (of a RAT) differ "at least in part" from the time and / or frequency resources of other SS / PBCH blocks (of another RAT) means that the broadcasting of the SS / PBCH blocks of different RATs is performed with partial overlap or complete absence of overlap between time and / or frequency resources of SS / PBCH blocks of one RAT and, respectively, time and / or frequency resources of SS / PBCH blocks of another RAT. Exactly how the synchronization channel raster is determined for use in 5G NR communication system is known, for example, from section 5.4.3 of TS 38.101-1 v18.2.0 specification (2023-06-30). Exactly how SS / PBCH positions in the time domain are determined for use in 5G NR communication system is known, for example, from section 4.1 of TS 38.213 v.17.5.0 specification (2023-06-26). Non-limiting examples of separation of transmissions of SS / PBCH blocks (including PSSs) will be described below with reference to Fig. 3, Fig. 4, Fig. 9.

[0091] Fig. 3 illustrates a non-limiting example of a possible arrangement of 6G SS / PBCH blocks in the time domain, taking into account the presence of 5G NR SS / PBCH blocks in said time domain, which may be applied in the technical solution according to the present disclosure. A sequence of one or more SS / PBCH blocks may be transmitted on a regular basis, for example, but not limited to, every 20 ms - 50 ms etc. A number of blocks in one sequence, as well as the regularity of transmission of this sequence, are configurable parameters. Some or all of the SS / PBCH blocks in one regularly transmitted sequence may be repeated within the sequence, and to individual transmissions of repeated SS / PBCH blocks different transmissionbeamformingschemes may be applied to improve the coverage of the network, in which data exchange between devices with massive antenna arrays according to spatial signal coding technology (Massive MIMO) is supported.

[0092] As shown in Fig. 3, it is proposed to transmit 6G SS / PBCH sequence in the second half of the first frame every 20 ms. The present disclosure should not be limited to the illustrated implementation example, since it is understood that if a sequence of 5G NR SS / PBCH blocks is transmitted in the second half of the first frame, then a sequence of 6G SS / PBCH blocks may be transmitted in the first half of said frame. In addition, not only the first frame in a certain period may be used, but the second frame or any subsequent frame. In addition, as noted above, the transmission periodicity of a sequence of SS / PBCH blocks may differ from the 20 ms periodicity shown, and the number of SS / PBCH blocks in a sequence may differ from four blocks shown in Fig. 3 up or down (e.g. equal to 1 block, 8 blocks, 64 blocks). Additionally, it should be noted that if separation of 5G NR SS / PBCH block transmissions and 6G SS / PBCH block transmissions is provided in the frequency domain (for example, as shown in Figs. 4 and 9), in the time domain such 5G NR SS / PBCH block transmissions and 6G SS / PBCH block transmissions may use same time resources according to the technical solution disclosed herein. And conversely, if separation of 5G NR SS / PBCH block transmissions and 6G SS / PBCH block transmissions is provided in the time domain (for example, as shown in Fig. 3), in the frequency domain such 5G NR SS / PBCH block transmissions and 6G SS / PBCH block transmissions may use same frequency resources according to the technical solution disclosed herein.

[0093] Thus, when one or more generated SS / PBCH blocks are emitted in step S110, each of the one or more generated SS / PBCH blocks may be emitted on OFDM symbols not used for emitting one or more SS / PBCH blocks in 5G NR communication system. In other words, each of the one or more generated SS / PBCH blocks may be emitted in an unoccupied half of a frame, and one or more SS / PBCH blocks used in 5G NR communication system are emitted on OFDM symbols of the other half of the same frame. Such separation of 6G SS / PBCH emission positions from 5G NR SS / PBCH emission positions in the time domain provides the possibility of coexistence of technologies operating simultaneously. In addition, such separation allows 6G to use the same or similar synchronization channel raster as the one used by 5G NR, which may simplify 6G implementation and deployment, and also provides low cell search delay for both technologies operating simultaneously.

[0094] Configuration of a specific position of a sequence of transmitted SS / PBCH blocks in the time domain may be specified and signaled in the SIB transmitted from the TRP and detected at the UE. By way of example, and not limitation, the SIB may include, to specify the configured transmission position of a sequence of SS / PBCH blocks in the time domain, one or more parameters of such transmission, for example, half-frame index 0 or 1, or it may be reported by the index of a particular OFDM symbol at what point in time the sequence of SS / PBCH blocks is to be transmitted.

[0095] The following Table 3 summarizes various possible broadcasting patterns of SS / PBCH blocks in the time domain, depending on carrier frequency, Subcarrier Spacing (SCS), duplex mode and other specified parameters. These patterns may be used in the present disclosure to determine / signal / use the exact transmission start position for a sequence of SS / PBCH blocks in a half frame in the time domain, but they should not be interpreted as being the limitations of the present disclosure. According to the formulas specified for one pattern or another in the column"Index of OFDM symbol in half-frame",the time domain position of the start of SS / PBCH (PSS) transmission in the half-frame can be determined precisely.

[0096] Table 3 -Applicable patterns of SS / PBCH blocks in time domain

[0097]

[0098] Fig. 4 illustrates a non-limiting example of a possible arrangement of 6G SS / PBCH blocks in a frequency domain, taking into account the presence of 5G NR SS / PBCH blocks in said frequency domain, which may be applied in the technical solution according to the present disclosure. In Fig. 4 it is shown that 6G SS / PBCH block is transmitted on subcarrier frequencies that do not completely overlap (namely, even partial overlap is not the case) with the subcarrier frequencies used to transmit 5G NR SS / PBCH block. More than twenty possible variants for placing 6G SS / PBCH block transmissions in frequency resources that do not overlap with the frequency resources used for 5G NR SS / PBCH transmissions are shown schematically in the diagram on the right side of Fig. 9. Such arrangements of SS / PBCH transmissions of different RATs (without any overlap in the frequency domain) are suitable when there is a sufficiently large bandwidth of the communication system operating frequencies (for example, two or more times larger) compared to a bandwidth occupied by the SS / PBCH block, which, in this case, allows to use the same synchronization channel raster advantageously for both transmissions of 5G NR SS / PBCH blocks and transmissions of 6G SS / PBCH blocks. Therefore, in this case, the configuration of the synchronization channel between the UE and the TRP in conditions of coexistence of different RATs (6G / 5G NR) simultaneously supported in the communication network may be simplified.

[0099] However, the example of complete separation of SS / PBCH block transmissions of different RATs in the frequency domain as illustrated in Fig. 4 should not be interpreted as the limitation of the present disclosure, since in cases of smaller bandwidth of the communication system operating frequencies (e.g., 1.5 times the bandwidth occupied by an SS / PBCH block) 6G SS / PBCH block transmissions may be carried out on frequency resources that partially overlap with frequency resources used for 5G NR SS / PBCH block transmissions. More than ten possible variants of such arrangements of SS / PBCH block transmissions of different RATs with partial overlap in the frequency domain are shown schematically in the diagrams on the left side of Fig. 9. As can be seen in the diagrams on the left side of Fig. 9, in these arrangement variants it is proposed not to use single shared synchronization channel raster (i.e., the 5G NR synchronization channel raster), but to introduce into the communication network configuration and use an additional 6G synchronization channel raster through the use of a frequency shift between these 5G NR / 6G synchronization channel rasters. In one non-limiting embodiment, the synchronization channel frequency offset of one RAT is selected to be greater than or equal to the half of the synchronization channel raster of the other RAT. In the other non-limiting embodiment, the synchronization channel frequency offset may be set to an integer multiple of the subcarrier spacing (SCS) used by the UE and the TRP for data exchange, for example, for broadcasting by the TRP each of one or more generated SS / PBCH blocks. The advantage of variants of such arrangements of SS / PBCH block transmissions of different RATs with partial overlap in the frequency domain consists in the ability of supporting the coexistence of different RATs (6G / 5G NR) in the communication network even with a relatively small bandwidth of communication system operating frequencies.

[0100] The following Table 4 summarizes various possible emission patterns of SS / PBCH blocks in the frequency domain depending on frequency range and other specified parameters. These patterns may be used in the present disclosure to determine / signal / use the exact transmission start position for a sequence of SS / PBCH blocks in the frequency domain, but they should not be interpreted as being the limitation of the present disclosure. According to the formulas specified for one or another frequency range in the column"SS / PBCH frequency position", the transmission start position of the SS / PBCH (PSS) in the frequency domain can be determined precisely.

[0101] Table 4 - Applicablearrangements of SS / PBCH blocks in frequency domain

[0102]

[0103] Configuration of a specific position of a sequence of transmitted SS / PBCH blocks in the frequency domain may be specified and signaled in the SIB transmitted from the TRP and detected by the UE. By way of example, and not limitation, the SIB may include, to specify a configured transmission position of a sequence of SS / PBCH blocks in the frequency domain, one or more of such transmission parameters, for example, a configured synchronization channel raster to be used along with 5G NR synchronization channel raster, a specific frequency at which the arrangement of one or more blocks from the SS / PBCH block sequence begins in the frequency domain, an index of a subcarrier from which the arrangement of one or more blocks from the SS / PBCH block sequence begins in the frequency domain etc.

[0104] Due to the above-described arrangements of a sequence of transmitted SS / PBCH blocks in the time and / or frequency domain, one or more of the following beneficial effects may be achieved: simplification of the cell search procedure, reduction in the number of erroneous detections by UEs of SS / PBCH blocks of a RAT, which such UEs do not support, etc. In addition, it should be noted that due to the arrangement variants described above for separating SS / PBCH block transmissions of different RATs in the time and / or frequency domain, it is possible to implement a communication system in which 6G SS / PBCH blocks are compatible with 5G NR RAT by reusing the sequence of 5G NR SS / PBCH blocks (as are) as 6G SS / PBCH blocks, i.e. without generating, in this case, 6G SS / PBCH blocks as described above with reference to Fig. 5 or Fig. 7.

[0105] Returning to Fig. 1, upon execution of step S110, the method proceeds to step S120, in which an uplink transmission is received from the UE that has performed, based on the detected one or more SS / PBCH blocks, the procedure for accessing the communication network served by said TRP. Here, it is assumed that the UE has successfully detected and decoded at least one SS / PBCH block of the RAT it supports, thanks to the features of the present disclosure described above regarding generation of SS / PBCH blocks and / or separation of transmissions of these blocks in the frequency and / or time domain, which allowed the UE to successfully complete the procedure for accessing the communication network. Thus, any then appropriate / required uplink transmission, including transmission with any payload and / or overhead data, without any limitation may be received from the UE at step S120. By performing the method described above with reference to Fig. 1, initial synchronization and subsequent communication between the TRP and the UE are ensured.

[0106] Fig. 10 illustrates the schematic representation of the TRP 300 according to the second aspect of the present disclosure, which is configured to perform the communication method according to the first aspect of the present disclosure due to at least that it includes a transmit-receive antenna unit 305 configured to communicate with UE and any other devices being within the coverage area of the respective cell, and a processor 310 operatively coupled with the transmit-receive antenna unit 305 and configured to perform the method according to the first aspect of the present disclosure or according to any possible example of the first aspect of the present disclosure. The Transmit-Receive Point (TRP) may be, but not limited to, a Base Station (BS), an Access Point (AP), or a Node B.

[0107] The TRP 300 is shown in Fig. 10 in a relatively simplistic, schematic form, therefore shown in this figure are not all components actually comprised in the TRP 300, but only those components with which the present disclosure is carried out. As is known, the TRP may comprise another components not shown in the figure, for example, a power supply, various interfaces, I / O means, interconnections, random access and read-only memory storing instructions executable by the processor 310 to carry out the method according to the first aspect of the present disclosure or according to any possible example of the first aspect of the present disclosure, as well as an operating system, etc. The transmit-receive antenna unit 305 may comprise a transceiver and an antenna coupled to each other. The antenna may be implemented as a massive or extremely massive MIMO antenna array with a large number of antenna ports, which supports hybrid analog and digital beamforming capabilities.

[0108] The processor 310 of the TRP 300 may be a central processing unit, a special-purpose processor, another processing unit, for example, a graphics processing unit (GPU), or a combination thereof. The processor 310 may be implemented as a circuit, for example as a Field-Programmable Gate Array (FPGA), an Application-Specific Integrated Circuit (ASIC), a System-on-Chip (SoC), etc.

[0109] Fig. 11 illustrates a flowchart of UE-implemented method of communication with TRP according to the fourth aspect of the present disclosure. It is assumed that the UE implementing this communication method is configured to interact with the TRP implementing the communication method described above with reference to Fig. 1. The UE-implemented method of communication with the TRP begins and proceeds to step S200, in which a procedure for accessing the communication network served by the TRP is performed. In this communication network access procedure, one or more SS / PBCHs emitted by the TRP are detected. In this case, (i) the M-sequence is used to detect the PSS included in the SS of the one or more SS / PBCH blocks being detected, and (ii) each of the one or more SS / PBCH blocks is detected on time and / or frequency resources that differ at least in part from those used to emit one or more SS / PBCH blocks in 5G NR communication system.

[0110] Fig. 12 illustrates an exemplary scheme of detection of one or more SS / PBCH blocks emitted by the TRP to implement by the UE the procedure of accessing the communication network provided by the TRP. The procedure for accessing the communication network served by said TRP includes, but is not limited to, any of an initial access procedure, a handover procedure, a failure recovery procedure (e.g. after a communication link failure). How these network access procedures as such may be implemented is known from the prior art, i.e. any known methods for implementing these procedures may be used in the present disclosure as long as they do not conflict with the aspects of the present disclosure disclosed herein.

[0111] As shown in Fig. 12, an exemplary flowchart of detecting one or more SS / PBCHs emitted by the TRP comprises performing at step S200.1 rough time and frequency synchronization with a cell, detecting at step S200.2 PSS signaling value, detecting at step S200.3 SSS signaling value, performing at step S200.4, based on the detected SSS, fine time and frequency synchronization with the cell, determining at step S200.5 identifier of the cell according to the equation , and detecting and decoding at step S200.6, based at least in part on the determined cell identifier, the PBCH. In this case, performing the procedure for accessing the communication network comprises, before or after steps S200.1-S200.6, step S200.7 of detecting and decoding the SIB emitted by the TRP.

[0112] As disclosed above when describing SS / PBCH block transmissions by the TRP, each of the one or more SS / PBCH blocks is detected by the UE on OFDM symbols not used by the 5G NR communication system for emitting the one or more SS / PBCH blocks. In addition, each of the one or more SS / PBCH blocks may be detected by the UE in an unoccupied half of a frame, and one or more SS / PBCH blocks used in 5G NR communication system are emitted on OFDM symbols of the other half of the same frame.

[0113] The synchronization channel raster according to which the UE may detect the one or more SS / PBCH blocks is positioned with a synchronization channel frequency offset relative to a synchronization channel raster according to which the one or more SS / PBCH blocks used in the 5G NR mobile communications are emitted. The synchronization channel frequency offset may be selected so as to provide partial overlap or complete absence of overlap in a frequency domain between each of the one or more detected SS / PBCH blocks and each of the one or more SS / PBCH blocks used by the 5G NR communication system. In a particular non-limiting example, the synchronization channel frequency offset is greater than or equal to a half of the synchronization channel raster according to which the one or more SS / PBCH blocks used by the 5G NR communication system are emitted. In the other non-limiting example, the synchronization channel frequency offset may be specified by an integer number of frequency intervals between neighboring subcarriers of each of the one or more SS / PBCH blocks being detected.

[0114] The PSS detection at step S200.2 may be performed on the basis of PSS candidates by performing matched filtering with the search for a frequency offset and value on the basis of maximum likelihood criterion, wherein to generate the PSS candidates at the UE used are predetermined polynomials and predetermined shifts, which are selected according to the criterion of minimizing the cross-correlation between the detected 6G PSSs and 5G NR PSSs, whose transmission may be detected in the time-frequency domain near the 6G PSS transmission. The same predetermined polynomials and predetermined shifts described above with reference to at least Fig. 5 and Fig. 7 that the TRP uses to generate the PSS may be used by the UE at this step S200.2 to detect the corresponding PSSs, so these predetermined polynomials and shifts will not be described again here. To implement matched filtering as above, the UE may use a matched filter configured based on (i) the characteristics and properties of the generated / detected PSS code sequences and / or (ii) the characteristics and properties of the corresponding ambiguity functions shown in Fig. 6 and Fig. 8. It will be appreciated that the matched filter may be implemented as software and / or hardware.

[0115] Returning to Fig. 11, upon execution of step S200, the method proceeds to step S210, in which in response to completion of the communication network access procedure, the uplink transmission to the TRP is performed. Here, it is assumed that the UE has successfully detected and decoded at least one SS / PBCH block of the RAT it supports, thanks to the features of the present disclosure described above regarding generation of SS / PBCH blocks and / or separation of transmissions of these blocks in the frequency and / or time domain, which allowed the UE to successfully complete the procedure for accessing the communication network. Thus, any then appropriate / required uplink transmission to the TRP, including transmission with any payload and / or overhead data, without any limitation may be performed by the UE at step S210. By performing the method described above with reference to Fig. 11, the initial synchronization and subsequent communication between the TRP and the UE are provided.

[0116] Fig. 13 illustrates the schematic representation of the UE 400 according to the fifth aspect of the present disclosure, which is configured to perform the communication method according to the fourth aspect of the present disclosure due to at least that it includes a transmit-receive antenna unit 405 configured to communicate with the TRP and any other devices being within the coverage area of the respective cell, and a processor 410 operatively coupled with the transmit-receive antenna unit 405 and configured to perform the method according to the fourth aspect of the present disclosure or according to any possible example of the fourth aspect of the present disclosure. The UE may be, but is not limited to, a mobile phone, a tablet, a laptop, a personal computer, a user wearable electronic device (for example, glasses, watches), AR / VR set, an 'Internet of Things' (IoT) device, an in-vehicle equipment or any other electronic mobile communication device. The UE may be differently referred to as the user terminal, user device, subscriber equipment, etc.

[0117] The UE 400 is shown in Fig. 13 in a relatively simplistic, schematic form, therefore shown in this figure are not all components actually comprised in the UE 400, but only those components with which the present disclosure is carried out. As is known, the UE may comprise another components not shown in the figure, for example, a power supply, battery, various interfaces, I / O means, interconnections, random access and read-only memory storing instructions executable by the processor 410 to carry out the method according to the fourth aspect of the present disclosure or according to any possible example of the fourth aspect of the present disclosure, as well as an operating system, etc. The transmit-receive antenna unit 405 may comprise a transceiver and an antenna coupled to each other. The antenna may be implemented as a massive or extremely massive MIMO antenna array with a large number of antenna ports, which supports hybrid analog and digital beamforming capabilities.

[0118] The processor 410 of the UE 400 may be a central processing unit, a special-purpose processor, another processing unit, for example, a graphics processing unit (GPU), or a combination thereof. The processor 410 may be implemented as a circuit, for example as a Field-Programmable Gate Array (FPGA), an Application-Specific Integrated Circuit (ASIC), a System-on-Chip (SoC), etc.

[0119] Fig. 14 illustrates the schematic representation of the communication system 500 according to the seventh aspect of the present disclosure. The communication system 500 comprises one TRP 300, which is installed to serve UEs 400 in three deployed cells 1, 2, 3. The TRP 300 may correspond to the TRP 300, which is described above in detail with reference to Fig. 10, and each UE 400 may correspond to the UE 400, which is described in detail with reference to Fig. 13, therefore, the detailed description of the TRP 300 and the UE 400 are not given here again. The communication system 500 may simultaneously support two active RATs from, for example, 4G LTE, 5G NR, 6G.

[0120] Specific details shown in Fig. 14 should not be construed as the limitations of the present technology, because the system 500 may have a different architecture and may be characterized / illustrated differently, for example, each cell of the cell 1, cell 2, cell 3 may correspond to its own TRP 300, a number of UE 400 in the cells may differ from the number shown, the cells 1, 2, 3 may be a single larger cell, a shape and space covered by the cells may differ from the ones shown, etc.

[0121] The present disclosure may further be implemented as a storage medium storing processor executable instructions, which, when executed by the processor of a device equipped with the transmit-receive antenna unit, cause the method of any aspect of the disclosed disclosure or any possible example of that aspect of the present disclosure to perform. The storage medium may be any long-term (non-transitory) computer-readable medium, a memory, a memory area, a storage device, etc., for example, but is not limited to, a hard disk, an optical medium, a semiconductor medium, a Solid State drive (SSD) or similar.

[0122] The technical solutions disclosed herein, the main features of which are (i) new methods of generating PSS and (ii) new methods of separating SS / PBCH transmissions of different existing technologies simultaneously supported in the network, in the frequency and / or time domain, provide, mainly, minimal cross-correlation of SS / PBCH blocks of different RATs, thereby allowing the SS / PBCH blocks of different RATs to be distinguished as clearly as possible by UEs supporting these different RATs. In addition, with the present disclosure, two RAT technologies may simultaneously coexist in a communication network and support a deployment scenario of these technologies with dynamic spectrum sharing.

[0123] The present disclosure may be used in 3GPP specification-compliant communication networks with TRPs and UEs, which support massive MIMO antenna technology with an extremely large number of digital antenna ports (e.g., 128), analog / digital single-beam / multi-beam beamforming, and TDD and / or FDD duplex modes. Other applications of the technology disclosed herein will become apparent to those ordinary skilled in the art upon reading this detailed description of the present application.

[0124] At least one of the features of the disclosed technical solution may be implemented by Artificial Intelligence (AI) model. The function associated with the AI may be performed by a read-only memory, random access memory, and processor(s) (CPU, GPU, NPU). The processor(s) controls the processing of input data in accordance with a predefined operating rule or an AI model stored in read-only memory and random access memory. The predefined operating rule or AI model is provided through training. Here, "provided through training" means that by applying a learning algorithm to a set of training data, a predefined operating rule or AI model with the desired characteristic is created (for example, an AI model to dynamically determine / redefine time-frequency positions of transmissions of SS / PBCH blocks of different RATs based on the current communication network / link condition, number of UEs and / or any other communication network / TRP / UE parameters), or an AI model to dynamically determine / redefine a particular M-sequence to be applied in a given situation determined by a state of communication network / line, number of UEs and / or any other communication network / TRP / UE parameters. The training may be performed in a device itself in which AI according to the embodiment is implemented, and / or may be implemented through a separate server / system.

[0125] The AI model may be a decision tree based algorithm or may consist of a plurality of neural network layers. Each layer has a plurality of weights and performs the operation of the layer through a calculation based on the result of the calculation in the previous layer and the application of a plurality of weights and other parameter values. Examples of decision tree based algorithms include a random forest, tree ensembles, etc., and examples of neural networks include, among other things, Convolutional Neural Network (CNN), Deep Neural Network (DNN), Recurrent Neural Network (RNN), Restricted Boltzmann Machine (RBM), Deep Belief Network (DBN), Bi-directional Network, Bi-directional Recurrent Deep Neural Network (BRDNN), Generative Adversarial Network (GAN), Transformer-based Architecture Networks, Deep Q-Network, etc.

[0126] A learning algorithm is a method of training a predetermined target device or target function based on a corresponding plurality of training data that causes, enables, controls, or provides an output of the target device or target function. Examples of learning algorithms include, but not limited to, supervised learning, unsupervised learning, semi-supervised learning or reinforcement learning, and so on.

[0127] One skilled in the art will appreciate that the various illustrative logical blocks (functional blocks or modules) and steps (operations) used in embodiments of the disclosed technical solution may be implemented by electronic hardware, computer software, or a combination thereof. Whether the functions are implemented by using hardware or software depends on particular applications and requirements to a design of an entire system. A person skilled in the art may use different methods to implement the described functions for each particular application, but it should not be considered that such an implementation will go beyond the scope of the embodiments disclosed in the application.

[0128] It should also be noted that the order of the steps of any disclosed method is not strict, because one or more steps may be rearranged in the actual order of execution and / or combined with one or more other steps, and / or divided into more sub-steps, for example, step S200.1 may be combined with step S200.2, step S200.3 may be combined with step S200.4, etc. Also, the embodiments of the disclosure may be combined to be implemented, when required. For example, portions of the methods provided by the disclosure may be combined with each other to enable the BS or the UE to operate.

[0129] Throughout this application, reference to an element in the singular form does not preclude the presence of a plurality of such elements in the actual implementation of the disclosure, and, conversely, reference to an element in the plural form does not exclude the presence of only one such element in the actual implementation of the disclosure. Any specific value or a range of values specified above should not be interpreted in a limiting sense, but rather such a specific value or range of values should be considered to represent the midpoint of the specified larger range, up to approximately 50% on either side of the specified value or specified smaller range.

[0130] While this disclosure has been made and described with reference to specific embodiments and examples thereof, those skilled in the art will understand that various modifications in form and content may be made without departing from the spirit and scope of this disclosure as defined by the appended claims and their equivalents. In other words, the foregoing detailed description is based on specific examples and possible non-limiting implementations of the present disclosure, but it should not be interpreted to mean that only the explicitly disclosed implementations are possible. It is intended that any modification or substitution that could be made to this disclosure by one of ordinary skill in the art without creative and / or technical contribution shall be within the scope of protection (with equivalents considered) provided by the following claims.

Claims

1.A method performed by a base station, the method comprising:generating one or more synchronization signal (SS) / physical broadcast channel (PBCH) blocks, wherein M-sequence is used to modulate a primary synchronization signal (PSS) included in an SS of the SS / PBCH block;transmitting the one or more generated SS / PBCH blocks, wherein each of the one or more generated SS / PBCH blocks is transmitted on first resource different at least in part from second resource used by an other communication system; andreceiving from the UE, based on detected one or more SS / PBCH blocks, an uplink transmission.2.The method of claim 1, wherein each of the one or more generated SS / PBCH blocks is transmitted on orthogonal frequency division multiplexing (OFDM) symbols not used by the other communication system.3.The method of claim 1, wherein a synchronization channel raster in which the one or more generated SS / PBCH blocks are transmitted is positioned with a synchronization channel frequency offset relative to a synchronization channel raster according to which one or more SS / PBCH blocks used in the other communication system are emitted,wherein the synchronization channel frequency offset is selected so as to provide partial overlap or complete absence of overlap in a frequency domain between each of the one or more generated SS / PBCH blocks and each of the one or more SS / PBCH blocks used by the other communication system.4.The method of claim 3, wherein the synchronization channel frequency offset is greater than or equal to a half of the synchronization channel raster according to which the one or more SS / PBCH blocks used by the other communication system are transmitted.5.The method of claim 3, wherein the synchronization channel frequency offset is specified by an integer number of frequency intervals between adjacent subcarriers of each of the one or more SS / PBCH blocks.6.The method of claim 1, wherein identifier is determined based on , whereinvalue is identified based on the PSS, andvalue is identified base on a secondary synchronization signal (SSS) included in the SS of the SS / PBCH block.7.The method of claim 6, wherein the PSS is generated by performing the following steps of:using a predetermined polynomial, generating the M-sequence;performing a cyclic shift of the generated M-sequence according to thevalue;performing binary phase-shift keying (BPSK) modulation on the cyclically shifted M-sequence;mapping the modulated M-sequence to subcarriers; andperforming cyclic prefix OFDM (CP-OFDM) on a symbol sequence obtained by the mapping.8.The method of claim 6, wherein the PSS is generated by performing the following steps of:using a predetermined polynomial defined by thevalue, generating the M-sequence;performing cyclic extension of the generated M-sequence to a length equal to a power of 2;performing / 2-BPSK-based modulation on the cyclically extended M-sequence;performing spectrum spreading of the modulated M-sequence by a discrete fourier transform (DFT);mapping the spectrum spreaded M-sequence onto subcarriers; andperforming CP-OFDM on a symbol sequence obtained by the mapping.9.A method performed by a user equipment (UE), the method comprising:receiving, from a base station, one or more synchronization signal (SS) / physical broadcast channel (PBCH) blocks, wherein M sequence is used to modulate a primary synchronization signal (PSS) included in an SS of the SS / PBCH block;performing a procedure for accessing the base station; andin response to completion of the procedure for accessing the base station, performing an uplink transmission to the base station,wherein each of the one or more SS / PBCH blocks is detected on first resource different at least in part from second resource used by an other communication system.10.The method of claim 9, wherein each of the one or more SS / PBCH blocks is detected on orthogonal frequency division multiplexing (OFDM) symbols not used by the other communication system.11.The method of claim 9, wherein a synchronization channel raster in which the one or more SS / PBCH blocks are detected is positioned with a synchronization channel frequency offset relative to a synchronization channel raster in which one or more SS / PBCH blocks used in the other communications are emitted,wherein the synchronization channel frequency offset is selected so as to provide partial overlap or complete absence of overlap in a frequency domain between each of the one or more detected SS / PBCH blocks and each of the one or more SS / PBCH blocks used by the other communication system.12.The method of claim 9, wherein the receiving of the one or more SS / PBCH blocks comprises the following steps of:performing rough time and frequency synchronization with a cell,detecting PSS signalingvalue,detecting SSS signalingvalue,performing, based on the detected SSS, fine time and frequency synchronization with the cell,determiningidentifier of the cell, anddetecting and decoding, based at least in part on the determinedcell identifier, physical broadcast channel (PBCH),wherein performing the procedure for accessing the base station comprises the step of:detecting and decoding SIB emitted by the base station.13.The method of claim 12, wherein the PSS detection is performed on a basis of PSS candidates by performing matched filtering with a search of a frequency offset and the value according to maximum likelihood criterion,wherein predetermined polynomials and predetermined shifts are used at the UE to generate the PSS candidates.14.A base station comprising:a transceiver; andat least one processor coupled with the transceiver and configured to:generate one or more synchronization signal (SS) / physical broadcast channel (PBCH) blocks, wherein M-sequence is used to modulate a primary synchronization signal (PSS) included in an SS of the SS / PBCH block,transmit the one or more generated SS / PBCH blocks, wherein each of the one or more generated SS / PBCH blocks is transmitted on first resource different at least in part from second resource used by an other communication system, andreceive from the UE, based on detected one or more SS / PBCH blocks, an uplink transmission.15.A user equipment (UE) comprising:a transceiver; andat least one processor coupled with the transceiver and configured to:receive, from a base station, one or more synchronization signal (SS) / physical broadcast channel (PBCH) blocks, wherein M sequence is used to modulate a primary synchronization signal (PSS) included in an SS of the SS / PBCH block;perform a procedure for accessing the base station; andin response to completion of the procedure for accessing the base station, perform an uplink transmission to the base station,wherein each of the one or more SS / PBCH blocks is detected on first resource different at least in part from second resource used by an other communication system.

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