Synchronization signal in a cellular network sharing spectrum

Abstract

A variety of transmission patterns are provided for the transmission of synchronization signals in an OFDM cellular communication system utilizing beam sweeping techniques. In the patterns, at least one OFDM symbol gap is provided between bursts of each synchronization signal to allow for switching between beams.

Description

Technical Field

[0001] The following disclosure relates to the transmission of synchronization signals, and in particular to the transmission of such signals when a beam-scanning base station is operating in a shared transmission spectrum. Background Technology

[0002] Wireless communication systems such as third-generation (3G) mobile phone standards and technologies are well-known. The 3G Partnership (3GPP) has developed such 3G standards and technologies. Generally speaking, third-generation wireless communication has been developed to the point of supporting macro cell mobile phone communication, and communication systems and networks have evolved towards broadband and mobile systems.

[0003] In a cellular wireless communication system, User Equipment (UE) connects to a Radio Access Network (RAN) via a radio link. The RAN includes a set of base stations that provide radio links to UEs located in cells covered by those base stations, and includes an interface connecting to the Core Network (CN), which has the function of controlling the overall network. It is understood that the RAN and CN each perform corresponding functions related to the overall network. For convenience, the term "cellular network" will be used to represent the combination of the RAN and CN, but it is understood that the term is also used to represent the individual systems performing the disclosed functions.

[0004] The 3rd Generation Partnership Project (3GPP) has developed the so-called Long Term Evolution (LTE) system, namely the Evolved Universal Mobile Communications System Territorial Radio Access Network (E-UTRAN), for mobile access networks supported by one or more macro cells called eNodeBs or eNBs (evolved NodeBs). More recently, LTE has further evolved into the so-called 5G or New Radio (NR) system, in which one or more cells are supported by base stations called gNBs. When NR was first proposed, it utilized the Orthogonal Frequency Division Multiplexing (OFDM) physical transmission format.

[0005] The NR protocol aims to provide the option of operating in unlicensed radio bands (known as NR-U). When operating in unlicensed radio bands, the gNB and UE must compete with other devices for physical media / resource access. For example, Wi-Fi, NR-U, and LAA may use the same physical resources.

[0006] The development trend of wireless communication is towards providing services with lower latency and higher reliability. For example, NR aims to support Ultra-reliable and low-latency communications (URLLC), while massive machine-type communications (mMTC) aims to provide low latency and high reliability for small data packets (typically 32 bytes). Currently, a user plane latency of 1ms with a reliability of 99.99999% has been proposed, and at the physical layer, a packet loss rate of 10% has been achieved. -5 Or 10 -6 The solution.

[0007] mMTC services are designed to support a large number of devices over a long lifespan using energy-efficient communication channels. In this scenario, data transmission between each device is sporadic and infrequent. For example, a single cell might need to support tens of thousands of devices.

[0008] The following disclosure relates to various improvements to cellular wireless communication systems. Summary of the Invention

[0009] The present invention is defined in the claims, wherein a method is provided for transmitting SS / PBCH bursts in an OFDM transmission system operating in frequency range 2 (FR2) and utilizing beam scanning technology, the method comprising the steps of: selecting a plurality of start positions for transmitting SS / PBCH bursts, wherein the selection of the plurality of start positions is such that there is at least one OFDM symbol gap between adjacent SS / PBCH bursts; and transmitting a plurality of SS / PBCH bursts, wherein each SS / PBCH burst begins at one of the selected plurality of start positions.

[0010] The system uses a subcarrier spacing of 120 kHz.

[0011] The plurality of start positions are located at OFDM symbol number {4,9,15,20}+28*n, where n=0,1,...,15, and reference symbol index 0 corresponds to the first symbol of the first slot in the half-frame of the transmitted SS / PBCH block.

[0012] The plurality of start positions are located at OFDM symbol number {2,8,15,20}+28*n, where n=0,1,...,15, and reference symbol index 0 corresponds to the first symbol of the first slot in the half-frame of the transmitted SS / PBCH block.

[0013] The plurality of start positions are located at OFDM symbol number {4,9,15,20}+28*n, where n=0,1,2,...,19, and reference symbol index 0 corresponds to the first symbol of the first slot in the half-frame of the transmitted SS / PBCH block.

[0014] The system uses a subcarrier spacing of 240 kHz.

[0015] The plurality of start positions are located at OFDM symbol number {8,14,20,32,38,44}+56*n, where n=0,1,2,...,10, and reference symbol index 0 corresponds to the first symbol of the first slot in the half-frame of the transmitted SS / PBCH block.

[0016] The plurality of start positions are located at OFDM symbol number {8,14,20,32,38,44}+56*n, where n=0,1,2,...,19, and reference symbol index 0 corresponds to the first symbol of the first slot in the half-frame of the transmitted SS / PBCH block.

[0017] The plurality of start positions are located at OFDM symbol number {8,16,32,44}+56*n, where n=0,1,2,...,15, and reference symbol index 0 corresponds to the first symbol of the first slot in the half-frame of the transmitted SS / PBCH block.

[0018] The plurality of start positions are located at OFDM symbol number {8,16,32,44}+56*n, where n=0,1,2,...,19, and reference symbol index 0 corresponds to the first symbol of the first slot in the half-frame of the transmitted SS / PBCH block.

[0019] The system uses a subcarrier spacing of 480 kHz.

[0020] The plurality of start positions are located at OFDM symbol number {4,12,20}+28*n, where n=0,1,2,...,21, and reference symbol index 0 corresponds to the first symbol of the first slot in the half-frame of the transmitted SS / PBCH block.

[0021] The plurality of start positions are located at OFDM symbol number {16,32,40,64,72,88}+112*n, where n=0,1,2,...,10, and reference symbol index 0 corresponds to the first symbol of the first slot in the half-frame of the transmitted SS / PBCH block.

[0022] The system uses a subcarrier spacing of 960 kHz.

[0023] The plurality of start positions are located at OFDM symbol number {8,20,32,44}+56*n, where n=0,1,2,...,15, and reference symbol index 0 corresponds to the first symbol of the first slot in the half-frame of the transmitted SS / PBCH block.

[0024] The plurality of start positions are located at OFDM symbol number {32,44,64,76,88,128,144,156,176,188}+224*n, where n=0,1,2,...,6, and reference symbol index 0 corresponds to the first symbol of the first slot in the half-frame of the transmitted SS / PBCH block.

[0025] The method further includes the step of sending indications of the plurality of starting positions.

[0026] The multiple starting positions are transmitted using the PBCH payload.

[0027] Reserved bits of the MIB payload are used as part of the indication of the plurality of start positions.

[0028] The number of the plurality of starting positions shall not exceed 128.

[0029] PBCH DMRS indicates at least a portion of the plurality of starting positions.

[0030] The multiple starting positions are indicated by the SS / PBCH candidate index. Attached Figure Description

[0031] The following description, by way of example only and in conjunction with the accompanying drawings, illustrates further details, aspects, and embodiments of the invention. For simplicity and clarity, elements in the drawings are shown, and these elements are not necessarily drawn to scale. For ease of understanding, the same reference numerals are included in the various drawings.

[0032] Figure 1 Displays selected components in a cellular communication system; and

[0033] Figures 2 to 5 This shows an example transmission mode. Detailed Implementation

[0034] Those skilled in the art will recognize and understand that the specific details of the described examples are merely illustrative of some embodiments, and that the teachings set forth herein apply to various alternative configurations.

[0035] Figure 1This diagram illustrates three base stations (e.g., eNB or gNB, depending on the specific cellular network standard and terminology) forming a cellular network. Typically, each base station is deployed by the cellular network operator to provide geographical coverage for UEs in that area. These base stations form a Radio Area Network (RAN). Each base station provides radio signal coverage for UEs in its area or cell. These base stations are interconnected via an X2 interface and connected to the core network via an S1 interface. As will be understood, only some basic details are shown here to illustrate the key characteristics of a cellular network. A PC5 interface is provided between multiple UEs for sidelink (SL) communication. Figure 1 The related interface and component names are for illustrative purposes only, and different systems operating on the same principles may use different naming conventions.

[0036] Each base station includes the hardware and software for implementing RAN functions, including communication with the core network and other base stations, the transmission of control and data signals between the core network and the UE, and maintaining or sustaining wireless communications for the UE associated with each base station. The core network includes the hardware and software for implementing network functions, such as overall network management and control, and the routing of calls and data.

[0037] The following lists various techniques for transmitting synchronization signals in cellular networks, which may be particularly well-suited for use with larger subcarrier spacing in shared transmission spectrum.

[0038] The UE employs a cell search procedure to synchronize time and frequency with the cell. This procedure also detects the cell's physical layer cell identifier. Synchronization is achieved based on the Primary Synchronization Signal (PSS) and Secondary Synchronization Signal (SSS) transmitted by the base station receiving the cell. The base station transmits the Physical Broadcast Channel (PBCH), PSS, and SSS in consecutive symbols within the SS / PBCH block. The PSS and SSS enable the UE to synchronize with the base station / cell, and the PBCH is decoded to provide basic system information, allowing the UE to complete configuration and initiate communication. The format of the SS / PBCH block is specified in TS38.211. The burst time span of the SS / PBCH block is 5 milliseconds, during which the base station can transmit SS / PBCH blocks for the active beam. The SS / PBCH blocks for the active beam are always limited to this 5-millisecond burst window. The transmission mode of the SS / PBCH block is specified in TS38.213.

[0039] Base stations can operate in beam-based mode, where transmission occurs on beams in specific directions, rather than omnidirectional. Proposals have been made to support up to eight beams in Frequency Range 1 (FR1) and up to 64 beams in Frequency Range 2 (FR2). Due to equipment limitations (particularly in FR2), base stations may not be able to transmit on all beams simultaneously; therefore, beam scanning operation can be used, where transmission occurs sequentially on each beam (or a subset of beams). When operating with beam scanning, each beam can transmit its own SS / PBCH block to ensure UE signal reception and synchronization.

[0040] The standard specifies that the UE determines system timing by identifying the system frame number (SFN), the half-frame flag, and the beam index. The beam index corresponds to the position of a given SS / PBCH block within a given half-frame in the SS / PBCH burst. The terms "beam index" and "SS / PBCH block candidate position index" are used synonymously below. After successful PBCH decoding, the SFN, half-frame flag, and beam index become available at the UE; the PBCH is part of the SS / PBCH block transmitted by the base station. The PBCH is used to transmit the master information block (MIB) received from higher layers, to which the physical layer adds additional information as a PBCH payload. The radio frame identifier, indicated by the 10-bit SFN (represented by bits s0 to s9), is ensured by transmitting six most significant bits (MSBs) s4 to s9 in the MIB payload. The MIB payload is a transport block provided to the physical layer from the medium access control (MAC) layer. The four least significant bits (LSBs) s0 to s3 of the SFN and the half-frame flag are transmitted as part of the PBCH payload. The physical layer adds the PBCH payload to the MIB payload, and after processing at the physical layer, transmits the combined MIB payload and PBCH payload through the PBCH.

[0041] For beam index identification, 6 bits b0-b5 are required to indicate the maximum of 64 beams allowed by FR2.3 (or the position of the SS / PBCH in that burst). LSBs b0-b2 are transmitted using the PBCH demodulation reference symbol (DMRS) by modulating the initialization sequence used to generate the DMRS. The three MSBs b3 to b5 are transmitted as part of the PBCH payload added to the MIB by the physical layer. More than 6 bits can be used to increase the number of beam or SS / PBCH candidate positions.

[0042] In order to utilize beam scanning and allow the transmission of SS / PBCH blocks, a suitable transmission mode is required, especially for the operation of FR2 unlicensed spectrum, which requires appropriate channel access procedures to share transmission resources.

[0043] The following section presents a design for SS / PBCH bursts that enables UE synchronization when operating in shared FR2 spectrum for beam scanning. Furthermore, specific transmission modes are disclosed to avoid overlap with scheduled transmissions, and an increased number of SS / PBCH candidate positions can be provided to address channel uncertainty issues in shared spectrum.

[0044] For operation on the 6 GHz unlicensed spectrum, the channel access procedure for transmitting SS / PBCH blocks employs a defined duration under the following conditions: (i) no unicast data, (ii) a transmission period of at most 1 millisecond, and (iii) a burst detection duty cycle of at most 1 / 20. For the 6 GHz spectrum, 3GPP TS37.213 specifies the use of a Type 2A DL channel access procedure for transmitting SS / PBCH blocks accompanied by non-unicast information, where the base station will perform sensing at intervals of at least 25 microseconds.

[0045] The 25-microsecond timeframe is divided into 16-microsecond intervals (sensing begins at the start), followed by a 9-microsecond sensing slot. These parameters are designed to ensure fair coexistence with Wi-Fi devices, which use a 16-microsecond Short Interframe Space (SIFS) and a 9-microsecond basic sensing slot for frequencies around 6 GHz. SIFS is the timeframe used by the Wi-Fi system to indicate latency during which the receiving device processes received frames and responds to indicate the correct reception of a data packet, as part of the hybrid-automatic repeat request (HARQ) mechanism. SIFS timeframes are also used when the receiving device participates in the channel access procedure within the request-to-send and clear-to-send processes.

[0046] To avoid interrupting ongoing communication within the SIFS gap, Wi-Fi systems allow a priority channel access procedure that includes the SIFS period and at least one sensing time slot. Therefore, even a priority transmission, for example, from a Wi-Fi access point, may only begin after the SIFS plus one sensing time slot, ensuring that ongoing communication between a pair of devices that might have a single SIFS gap is not disrupted.

[0047] For the 802.11ad enhancements for operation in the 60GHz region, the SIFS time period has been updated to 3 microseconds and the duration of the sensing time slot has been updated to 5 microseconds, as defined in Section 21.12.4 of Part 11 of the relevant Wi-Fi standard.

[0048] The timing adjustments made in 802.11ad can be applied to cellular channel access procedures to ensure fair coexistence. Therefore, the UE can use at least 8 microseconds of channel sensing time before performing SS / PBCH transmission. This 8-microsecond time period is a combination of a 3-microsecond SIFS time period and a 5-microsecond sensing time slot.

[0049] This 8-microsecond time interval is divided into two intervals: a 3-microsecond interval followed by a 5-microsecond interval. The base station can only transmit SS / PBCH without unicast data when both intervals are detected to be idle (i.e., the energy detected on the channel within both intervals is below a specified energy detection threshold). Other conditions, such as duty cycle and maximum channel occupancy time, can also be used if required by relevant regulations. The above sensing can be omnidirectional or directional.

[0050] The new reference timing described in 802.11ad can also be used for deterministic channel access in cellular operations. When a base station or UE obtains channel access on a shared spectrum, there is a gap of at least 3 microseconds (because one device begins transmission through a channel obtained by another device, or because the same device transmits after a gap), requiring the device to perform 3 microseconds of channel sensing. This channel sensing is equivalent to type 2B channel sensing applicable to 60 GHz operations.

[0051] Similarly, if channel access has been acquired and there is a gap of less than 3 microseconds, transmission can be resumed without channel sensing. This behavior is permissible because no device should acquire the channel in the absence of a sensing period of at least 3 microseconds, and therefore no transmission should commence during a gap of less than 3 microseconds. Considering coexistence with 802.11ad devices, this channel sensing is equivalent to Type 2C channel sensing for 60GHz operation.

[0052] As mentioned above, when using beam scanning, the base station does not transmit on all beams simultaneously. This means that when using another beam, there are variable time intervals in each beam direction. During these intervals, other devices may have already acquired the channel and started transmitting. Therefore, a channel access procedure of at least 8 microseconds, as described above, should be performed before starting transmission on a new beam, even if channel access has already been acquired. As mentioned above, the sensing can be performed omnidirectionally or directionally. This applies to the transmission of an SS / PBCH block for a given beam.

[0053] The standard allows for high-frequency operation using subcarrier spacing of 60 kHz or greater. Revision 15 (Rel-15) standardized SS / PBCH block modes for 120 kHz and 240 kHz SCS, with 240 kHz used solely for SS / PBCH block transmission, not for data transmission. For higher frequency operation, where carrier bandwidth can be very large (GHz), larger SCS may be needed to help address the large-size FFT, which can become a bottleneck when the number of subcarriers becomes very large. In this regard, for FR2, choosing a fairly large SCS, such as 960 kHz or even 1920 kHz, may be advantageous. This would require designing new SS / PBCH block modes to be compatible with SS / PBCH block transmissions in different beam directions and could potentially allow different SCS to be used for SS / PBCH blocks as well as other control and data transmissions.

[0054] For operation in unlicensed spectrum, Wi-Fi and its corresponding high-frequency technology, WiGig (which includes the 802.11ad standard), follow a "listen-before-speak" channel access procedure. For coexistence in shared unlicensed spectrum, cellular base stations can apply an equivalent procedure. Current designs for SS / PBCH block transmission in 120kHz and 240kHz SCSs feature SS / PBCH blocks transmitted sequentially from different beams. This is attractive for operation in licensed spectrum, allowing SS / PBCH blocks to be compressed into shorter time spans, thus maximizing scheduling / control flexibility for the remaining time. However, when operating in unlicensed spectrum, as mentioned above, a channel access procedure may be required before transmission can begin on a new beam, thus hindering continuous transmission between beams. The channel access procedure discussed above may be appropriate before transmission can begin on a beam where a gap already exists in transmission on that beam.

[0055] The following describes designs for SS / PBCH block transmission in beam-based transmission systems. These designs are independent of specific types of channel access procedures during beam switching. The proposed designs provide tolerance for beam switching delays and associated transitions that may affect the detection probability of SS / PBCH blocks transmitted without sufficient gaps for beam switching. The disclosed techniques employ SS / PBCH block bursts with time gaps between consecutive SS / PBCH blocks. Therefore, a method is provided for transmitting synchronization signals from a base station on multiple beams, wherein the signals are arranged in bursts with time gaps between signals transmitted on each beam.

[0056] When operating at a 120 kHz SCS, each OFDM symbol is approximately 8.9 microseconds. The indicated 8-microsecond sensing period can therefore be accommodated within the interval of one OFDM symbol (at 120 kHz). At 240 kHz, each OFDM symbol is approximately 4.5 microseconds, therefore two OFDM symbols are required to allow for an 8-microsecond sensing period. Similarly, for 480 kHz and 960 kHz SCS, four and eight OFDM symbols are required, respectively, to perform channel sensing for at least 8 microseconds.

[0057] The following describes the design of SS / PBCH block bursts for SCSs from 120kHz to 960kHz. All designs presented here ensure a minimum gap to allow channel sensing prior to beam switching. Furthermore, since the SCS of the SS / PBCH block may differ from the SCS of the control / data blocks, these designs aim to maximize the opportunities for DL ​​and UL control for different parameter sets (SCS). DL control is typically transmitted in the first few symbols of a time slot within the control (data) parameter set, helping the base station schedule resources for DL ​​and UL transmissions. UL control is typically scheduled in the last few symbols of a time slot, helping the base station receive HARQ feedback and UL control information.

[0058] Figure 2 Two proposed designs (D1-120 and D2-120) for SS / PBCH block modes with a 120kHz subcarrier spacing are shown. The goal of this design is to harmonize the operation of SS / PBCH blocks using 120kHz transmission and to maximize the possibility of DL / UL controlled transmission opportunities for SCS starting at 60kHz. 60kHz was chosen because lower SCSs such as 15kHz and 30kHz are only permitted for use in the lower frequency range FR1 of 3GPP. Figure 2 This shows a time slot (14 symbols) for the 60kHz SCS, which spans 28 and 56 symbols for the 120kHz and 240kHz SCSs, respectively. The first three rows show the symbols for the 60kHz to 120kHz SCSs, with the applicable SCS indicated in the first column. For each corresponding SCS in a row, the first two symbols are highlighted to indicate possible downlink control transmissions, and the last two symbols are highlighted to indicate possible uplink control transmissions. The bottom two rows provide proposed designs (D1-120 and D2-120) for the SS / PBCH block mode of the 120kHz SCS.

[0059] Figure 2 In the design for D1-120, the candidate positions are:

[0060] ·D1_120={4,9,15,20}+28*n

[0061] n = 0, 1, 2, ..., 15

[0062] Figure 2The D1-120 design incorporates at least one OFDM symbol gap between consecutive SS / PBCH blocks, providing over 8 microseconds for channel sensing after beam switching. This design avoids any overlap with 60kHz SCS DL and UL control. For the two slots of the 120kHz SCS, this provides one non-overlapping DL and UL control. It also provides gaps at symbols 13 and 14, allowing for separate implementation of single-symbol UL and single-symbol DL control. For the 240kHz SCS, this provides half the control opportunities for DL ​​and UL.

[0063] Figure 2 In the design for D2-120, the candidate positions are:

[0064] ·D2_120={2,8,15,20}+28*n

[0065] n = 0, 1, 2, ..., 15

[0066] This design (D2-120) also has at least one OFDM symbol gap between each SS / PBCH block, thus providing at least 8 microseconds for channel sensing between consecutive beams. Besides having a similar gap introduction to D1_120, D2_120 has different compromises regarding overlap with control positions. Since only a single symbol's control resource set is allowed, DL control can be transmitted within a single symbol. Conversely, for UL control, a handover gap, timing advance, and uplink control transmission on at least one symbol are required. Taking advantage of this difference between UL and DL control, the positions of the first two SS / PBCH candidates in D2_120 are slightly shifted to partially overlap with 60kHz DL control. 60kHz DL control transmission at the beginning of a time slot has only no overlap on the first symbol, but for 120 and 240kHz SCS, there are more opportunities for non-overlapping DL and UL control transmissions, such as... Figure 2 As shown.

[0067] Figure 2 The design provides 4 SS / PBCH blocks per slot (0.25 microseconds) for the 60kHz SCS. Therefore, there will be 80 candidate SS / PBCH block locations within 5 milliseconds (during the SS / PBCH burst).

[0068] When the transport carrier is part of a licensed spectrum, the first 64 SS / PBCH block candidate locations can be used. However, when the transport carrier is part of a shared unlicensed spectrum, SS / PBCH block locations may be unavailable due to channel access uncertainty (i.e., channel sensing detects a transport when switching to a new beam). If some locations are unavailable due to a lack of channel access, additional SS / PBCH candidate locations can be provided within the burst span for utilization. Each SS / PBCH block can be identified using its beam index, thereby providing the UE with the necessary information to determine complete system timing information.

[0069] These designs ensure that all candidate positions on the SS / PBCH are available for transmission within a 5-millisecond window. This 5-millisecond window is reserved because it is defined as the burst time of the SS / PBCH. If this burst time is modified, additional positions can be made available on the SS / PBCH using the same method by utilizing all matching positions within the updated burst time.

[0070] For the proposed designs, each design provides two SS / PBCH block candidate positions within a 120kHz time slot. Since there are 40 time slots in a 120kHz SCS within 5 milliseconds, this design will provide a total of 80 SS / PBCH candidate positions. Therefore, the candidate positions for the 120kHz SCS design D1-120 are:

[0071] ·D1_120={4,9,15,20}+28*n

[0072] n = 0, 1, 2, ..., 19

[0073] The only difference is the possible values ​​of n, which range from 0 to 19. The same variation can also be applied to... Figure 2 The second design in this series is D2-120. Of these 80 positions, the beam index (or more precisely, the index of the SS / PBCH candidate positions) will require 7 bits. In conventional designs, 6 bits are used to transmit the index of one of the 64 beams, with 3 bits transmitted using the PBCH DMRS and 3 bits transmitted as the PBCH payload. Figure 2 The design for the 120kHz SCS proposal requires the transmission of an additional bit to enable the UE to determine system timing information. The technique for transmitting the beam index (or SS / PBCH candidate position index) is disclosed below.

[0074] Figure 3Proposed designs for SS / PBCH block modes with a 240kHz subcarrier spacing are shown. These designs aim to coexist with SS / PBCH blocks using 120kHz transmission to maximize the possibility of DL / UL control transmission opportunities for SCS starting at 60kHz. Figure 3 This displays a time slot (14 symbols) for the 60kHz SCS, which is equivalent in time to 28 symbols for the 120kHz SCS and 56 symbols for the 240kHz SCS. The first three rows show the symbols from the 60kHz to the 120kHz SCS, with the relevant SCS indicated in the first column. For each corresponding SCS in a row, the first two symbols are highlighted to indicate possible downlink control transmissions, and the last two symbols are highlighted to indicate possible uplink control transmissions. The bottom two rows provide proposed designs (D1-240 and D2-240) for the SS / PBCH block mode of the 240kHz SCS.

[0075] For 240kHz SCS, Figure 3 The candidate position for the first design (D1-240) is:

[0076] ·D1_240={8,14,20,32,38,44}+56*n

[0077] n = 0, 1, 2, ..., 10

[0078] In achieving 64 beams, for n=10, only the first 4 candidate SS / PBCH positions are used.

[0079] This design ( Figure 4 The D1-240 provides at least two OFDM symbol gaps between consecutive SS / PBCH blocks, offering over 8 microseconds of time for channel sensing between consecutive beam transmissions. This design avoids overlap with 60kHz and 120kHz SCS DL and UL control opportunities. Figure 3 The four time slots of the 240kHz SCS shown provide three non-overlapping control opportunities out of four DLs and three non-overlapping control opportunities out of four ULs. One advantage of this design is that it provides six SS / PBCH candidate positions within 250 microseconds, thus providing 64 SS / PBCH candidate positions within a timeframe of less than 2.75 milliseconds. Adapting all SS / PBCH candidate positions in a shorter time improves the flexibility of data / control transmission within the user's beam, thereby enhancing system efficiency.

[0080] For unlicensed spectrum, the possibility of SS / PBCH locations being unavailable due to channel uncertainty can be compensated for by making all candidate locations available during the SS / PBCH burst period. Figure 4 The design D1-240 in the model will have 120 positions within 5 milliseconds. These candidate positions are as follows:

[0081] ·D1_240={8,14,20,32,38,44}+56*n

[0082] n = 0, 1, 2, ..., 19

[0083] For 120 candidate locations, 7 bits are needed to transmit the beam index (or the index of the SS / PBCH candidate locations). This means that there is one extra bit in addition to the traditional design of 64 beam locations in 3GPP Release 15 (Rel-15) / Release 16 (Rel-16).

[0084] Figure 4 The candidate positions for the second design, D2-240, for 240kHz SCS are:

[0085] ·D2_240={8,16,32,44}+56*n

[0086] n = 0, 1, 2, ..., 15

[0087] The first advantage of this design (D2-240) is that the minimum distance between two consecutive SS / PBCH blocks is at least four OFDM symbols of the 240kHz SCS. This means that the design can be used in other situations or at operating frequencies with longer channel sensing periods. The minimum gap of four OFDM symbols of the 240kHz SCS means that even a sensing time of 16 microseconds can be accommodated. Another advantage of this design is that it has zero overlap with any DL / UL control opportunity from the 60kHz SCS parameter set to the 240kHz SCS parameter set. Therefore, the design does not impose limitations on DL / UL control, making system operation more convenient, and it does not restrict uplink-direction scheduling transmissions or HARQ feedback transmissions, which is invaluable for services with stringent latency requirements.

[0088] For the unlicensed scenario, all possible SS / PBCH candidate locations adapted within the SS / PBCH burst window can be used. In this unlicensed scenario, the candidate locations for this design are:

[0089] ·D2_240={8,16,32,44}+56*n

[0090] n = 0, 1, 2, ..., 19

[0091] This provides 80 candidate locations for SS / PBCH transmission, which require an indication of the beam index (SS / PBCH candidate location index), which needs to include an indication of 7 bits or bits.

[0092] Figure 4 A design for SS / PBCH block bursts with a 480kHz subcarrier spacing is shown. This design supports the transmission of SS / PBCH blocks using 480kHz SCS, while fully allowing the opportunity for DL / UL control transmissions of all SCSs starting from 60kHz. Figure 4 This diagram shows that one time slot (14 symbols) of the 60kHz SCS is equivalent to four time slots of the 240kHz SCS. The diagram consists of four stacked subplots, each showing one time slot of the 240kHz SCS.

[0093] for Figure 4 Each subgraph in the diagram displays symbols for the SCS from 60kHz to 960kHz in the first five rows, with the relevant SCS indicated in the first column. For each corresponding SCS in a row, the first two symbols in a time slot are highlighted to indicate possible downlink control transmissions, and the last two symbols are highlighted to indicate possible uplink control transmissions. The bottom two rows provide two proposed designs (D1-480 and D2-480) for SS / PBCH block bursts of the 480kHz SCS.

[0094] Figure 4 The design incorporates at least four symbol gaps between consecutive SS / PBCH blocks, allowing for channel access periods of up to 8 microseconds. The first design (D1-480) is suitable for data / control SCSs of 240kHz or higher because its construction does not account for the DL / UL control positions of the 60kHz and 120kHz SCSs. This design does not overlap with the DL / UL control of the 240kHz SCS, but partially overlaps with all DL / UL control positions of the 480kHz SCS.

[0095] For 480kHz SCS, Figure 4 The candidate positions for design D1-480 are:

[0096] ·D1_480={4,12,20}+28*n

[0097] n = 0, 1, 2, ..., 21

[0098] For n=21, only the first candidate position is used to achieve 64 SS / PBCH candidate positions.

[0099] In the unlicensed scenario, all SS / PBCH positions can be used within a 5-millisecond burst span, thus n ranges from 0 to 79, providing 240 SS / PBCH candidate positions. This will require an 8-bit indicator to specify the SS / PBCH candidate positions.

[0100] Figure 4 The second design (D2-480) is more inclusive and, at the cost of reduced SS / PBCH density per unit time, ensures no overlap in DL / UL control timings starting from the 60kHz control / data SCS. This design has zero overlap with DL / UL control timings at 60, 120, and 240kHz SCSs, while having very limited overlap with DL / UL control timings at 480 and 960kHz SCSs.

[0101] For 480kHz SCS, Figure 4 The second candidate position for the design (D2-480) is:

[0102] ·D2_480={16,32,40,64,72,88}+112*n

[0103] n = 0, 1, 2, ..., 10

[0104] For n=10, the first 4 candidate positions are used to achieve 64 SS / PBCH candidate positions.

[0105] For the unlicensed scenario, n ranges from 0 to 19, providing 120 SS / PBCH candidate positions. This will require a 7-bit indicator to specify the SS / PBCH candidate positions.

[0106] The key feature of the D2_480 design is its ability to achieve smooth coexistence when the system allows any seed carrier spacing starting from 60kHz for DL / UL control and data transmission. On the other hand, the D1_480 design does not consider overlap with the 60kHz and 120kHz subcarrier spacings. This allows the D1_480 to have a higher SS / PBCH density in time, and SS / PBCH bursts to complete in a shorter time, thereby improving system efficiency.

[0107] The fundamental principle behind the first design, D1_480, is that, for example, if the system operates such that the 480kHz and 960kHz subcarrier spacing is used only for SS / PBCH, while data and control are at 240kHz or higher, then D1_480 can be a fairly excellent design. On the other hand, if it is necessary to ensure that the subcarrier spacing starting from 60kHz coexists with all the subcarrier spacings of FR2, then D2_480 is a better choice.

[0108] Figure 5A proposed design for SS / PBCH block bursts with a subcarrier spacing of 960 kHz is shown. Figure 5 The diagram shows that one time slot (14 symbols) of the 60kHz SCS is equivalent to four time slots of the 240kHz SCS. Figure 6 consists of four stacked subplots, each showing one time slot of the 240kHz SCS.

[0109] For each subgraph, the first five rows display symbols for the SCS from 60kHz to 960kHz, with the relevant SCS indicated in the first column. For each corresponding SCS in a row, the first two symbols in a time slot are highlighted to indicate possible downlink control transmissions, and the last two symbols are highlighted to indicate possible uplink control transmissions. The bottom two rows provide two proposed designs for SS / PBCH block bursts of the 960kHz SCS.

[0110] Figure 5 The designs (D1_960 and D2_960) have at least 8-symbol gaps between consecutive SS / PBCH blocks, allowing for channel access periods of up to 8 microseconds. The first design is suitable for data / control SCSs of at least 240kHz or higher because its construction does not account for the DL / UL control positions of the 60 / 120kHz SCS. This design does not overlap with the DL / UL control of the 240, 480, and 960kHz SCSs. This is advantageous in allowing this subset of SCSs (240, 480, and 960kHz) to be used for both SS / PBCH and control / data without overlap or limitation on DL / UL control opportunities due to SS / PBCH transmission.

[0111] For 960kHz SCS, Figure 5 The first candidate position for design D1-960 is:

[0112] ·D1_960={8,20,32,44}+56*n

[0113] n = 0, 1, 2, ..., 15 (to obtain 64 beams)

[0114] For the unlicensed scenario, n ranges from 0 to 79, providing 320 SS / PBCH candidate positions. This would require 9 bits of indication to specify the SS / PBCH candidate positions. To cover overhead, only the first 256 candidate positions can be allowed, which can be indicated using 8 bits of signaling.

[0115] Figure 5The second design (D2-960) ensures zero overlap in DL / control opportunities starting from the control / data SCS at the cost of reduced SS / PBCH density per unit time. This design exhibits zero overlap with DL / UL control for all SCSs from 60kHz to 960kHz. Therefore, this could be a good option if all SCSs are considered necessary for DL / UL control.

[0116] For 960kHz SCS, Figure 5 The second candidate position for design D2-960 is:

[0117] ·D2_960={32,44,64,76,88,128,144,156,176,188}+224*n

[0118] n = 0, 1, 2, ..., 6

[0119] For n=6, the first 4 candidate positions are used.

[0120] For the unlicensed scenario, n ranges from 0 to 19, providing 200 SS / PBCH candidate positions. This will require an 8-bit indicator to specify the SS / PBCH candidate positions.

[0121] When the data / control SCS is 240kHz or higher, the reader will realize that the designs of D1_480 and D1_960 have been optimized. These designs may be suitable for systems where control and data operation is limited to SCSs of 240kHz or higher. The other two designs for these SCSs, D2_480 and D2_960, reduce the SS / PBCH density over time but allow operation in any SCS starting from 60kHz, thus having no limitations on the use of the data / control SCS.

[0122] As stated above, the terms "beam index" and "SS / PBCH block candidate position index" are used synonymously herein. The objective of the following disclosure is to transmit an index for each SS / PBCH candidate position so that a UE decoding each SS / PBCH block can determine the SS / PBCH candidate positions within the SS / PBCH burst. Based on this determined position, the UE can determine complete system timing information by combining this position with the SFN and half-frame flag. As stated above, various SS / PBCH burst block designs have been proposed that increase the number of candidate positions, thus allowing for channel access uncertainty. This may increase the size of the SS / PBCH candidate position index.

[0123] For example, for a maximum of 64 beams (requiring 6 bits of SS / PBCH candidate index indication), the design proposed for a 120kHz SCS increases the number of possible candidate positions to 80, requiring 7 bits of indication. In all the SS / PBCH burst designs mentioned above for SCSs from 120kHz to 960kHz, 7, 8, or 9 bits of indication are required. In traditional PBCH designs, 3 LSBs are carried in the PBCH DMRS and 3 MSBs in the PBCH payload, generated and added by the physical layer. The following disclosure discusses methods for transmitting SS / PBCH candidate positions, which may be particularly suitable for burst designs discussed above.

[0124] The location indication can be provided through the PBCH payload. Additional bits for the SS / PBCH candidate index can be added to the PBCH payload along with the MSB. This increases the size of the PBCH payload generated by the physical layer from 8 bits to 9, 10, or 11 bits, an increase of 1, 2, or 3 bits respectively. While adding additional bits is technically simple, the physical layer processing must be modified. In traditional designs, an 8-bit PBCH payload is added to a 24-bit MIB payload, resulting in a 32-bit combined payload on which the physical layer processing is applied. If the number of bits increases to more than 32, many aspects of physical layer processing, such as scrambling, CRC addition, and interleaving, may require significant redesign, which can be unattractive due to its high complexity.

[0125] To avoid increasing the payload size, a reserved bit in the MIB payload can be used to add a bit for the candidate location index indication. The size of the candidate location index can thus be increased by one bit (from 64 locations to 128 locations) without increasing the amount of data transmitted or requiring a redesign of the physical layer processing. This can be achieved by limiting the design to a maximum of 128 candidate locations, although the design can actually accommodate more than 128 locations.

[0126] In another example, the PBCH DMRS can be used to indicate the SS / PBCH candidate index. In a traditional design, the three LSBs of the SS / PBCH candidate index are carried by the PBCH DMRS by selecting eight possible DMRS sequences. The number of DMRS sequences can be increased as needed to transmit additional bits of the SS / PBCH candidate index. For example, 16 or 32 DMRS sequences can be used to accommodate one or two additional bits of the SS / PBCH candidate index, respectively. For this strategy, it is not necessary to increase the number of DMRS sequences to 32 for all SCSs. In practice, to avoid making blind decoding of the DMRS sequences by the UE overly complex, only SCSs requiring 8 bits for the SS / PBCH candidate position indication use 32 sequences. The PBCH DMRS for the remaining DMRS sequences can use only 16 DMRS sequences.

[0127] In the SS / PBCH burst design proposed above, the 120kHz and 240kHz designs only require 7 bits for SS / PBCH candidate position indication, while the 480kHz and 960kHz SCS designs require more than 7 bits. Therefore, base stations transmitting SS / PBCH blocks with 120kHz or 240kHz SCS will only use 16 PBCH DMRS sequences, while more PBCH DMRS sequences will be used for 480kHz and 960kHz SCS.

[0128] For designs that can accommodate more than 128 positions in a single SS / PBCH burst, a compromise can be achieved by limiting the maximum number of SS / PBCH candidate positions to the first 128 positions. This allows for the uniform use of a 7-bit indicator for SS / PBCH block positions, which can be achieved by increasing the number of possible DMRS sequences to 16. This is likely a good trade-off between the added timing flexibility and the limited increase in DMRS decoding complexity.

[0129] For a 6-bit SS / PBCH candidate position indication, represented as b0 to b5, conventional designs transmit bits b0 to b2 on the PBCH DMRS and bits b3 to b5 on the PBCH payload. In the case of a 7-bit SS / PBCH candidate position indication (represented as b0 to b6), one approach is to use a conventional bit mapping for the first 6 bits and add the MSB (i.e., b6) to the indication provided by the DMRS sequence. This means the DMRS will carry 4 bits (b0 to b2 and b6), while the PBCH payload will carry b3 to b5. A potential drawback of this design is that adjacent SS / PBCH candidate positions will use the same PBCH DMRS, affecting detection quality. To overcome this problem, 4 LSBs, i.e., bits b0 to b3, are mapped to the PBCH DMRS and can be transmitted through 16 possible PBCH DMRS sequences, while 3 MSBs, i.e., b4 to b6, can be added to the PBCH payload.

[0130] If more than one bit needs to be added to the existing 6-bit SS / PBCH candidate position indicator, a hybrid approach combining the two methods described above can be used. This approach, employing both DMRS and payload indicators simultaneously, increases the number of transmitted bits by more than three. For example, to support an 8-bit SS / PBCH position index, two additional bits need to be transmitted compared to the traditional 6-bit design. One additional bit can be transmitted on the PBCH as payload (using the techniques described above), and one bit can be transmitted by increasing the number of DMRS sequences to 16 (using the techniques described above). Furthermore, this hybrid approach can accommodate a larger number of SS / PBCH candidate positions.

[0131] The discussion above regarding the proposed SS / PBCH block designs was primarily conducted in the context of unlicensed spectrum, where channel sensing is required during beam switching. However, readers will recognize that these designs can also be seamlessly applied to licensed spectrum. This facilitates the adoption of the same SS / PBCH burst design for both licensed and unlicensed spectrum. Another advantage is that the proposed designs help to better absorb the transients caused by beam switching, which could otherwise degrade the quality of continuously transmitted SS / PBCH blocks.

[0132] The solutions discussed above can replace existing designs for licensed spectrum in 120kHz and 240kHz SCS, or the proposed solutions can be used exclusively for unlicensed shared spectrum. Devices are aware of whether they operate on licensed or unlicensed spectrum, thus enabling the use of the appropriate solution without confusion.

[0133] This paper proposes several methods to indicate the number of additional SS / PBCH block candidate positions added in an SS / PBCH burst. The issue of additional SS / PBCH candidate positions is primarily addressed in unlicensed shared spectrum scenarios, accommodating more positions than the maximum number of beams to compensate for channel access uncertainties. This design can be seamlessly applied if the number of beams in licensed or unlicensed spectrum increases to more than 64, requiring more than 6 bits of SS / PBCH candidate positions.

[0134] 3GPP NR Release-15 has limited the burst length to a half-frame time period, or 5 milliseconds. This essentially means that all candidate positions for a given frequency range always match this 5-millisecond time period. The design presented in this paper provides symbol positions starting from reference symbol 0. Consistent with existing designs, this reference symbol 0 is considered the first symbol of the half-frame. However, for higher frequency operations, the symbol time will become very small with the use of very large SCS. This could lead to burst lengths changing from 5 milliseconds to smaller time intervals. The proposed design remains valid even if the burst length changes to a different duration. In the proposed design, symbol 0 (the reference point) needs to be mapped to the new reference symbol as a minor adjustment to implement a design suitable for any new burst duration. Changes in burst duration may also affect the total number of candidate positions for carriers in unlicensed spectrum.

[0135] The proposed design provides 64 candidate locations, and 3GPP has already decided to support up to 64 beams in FR2 and FR2 extensions up to 71 GHz. Readers will recognize that the proposed SS / PBCH burst design can be easily adapted to achieve fewer or more SS / PBCH candidate locations. To achieve an even smaller number of beam locations, such as 32 or 16, the first 32 or 16 candidate locations in the proposed design can be used. For designs with more than 64 beams, ultimately using more SS / PBCH block locations, additional locations can be reused from the proposed design to obtain the desired number of candidate locations.

[0136] Clearly, the above disclosure includes methods for a base station to transmit the signals discussed herein on an appropriate beam for reception by a UE. For example, the disclosure includes the following steps: transmitting a synchronization signal at a first candidate location on a first beam, switching to a second beam and performing a channel access procedure for the second beam, and subsequently transmitting a second synchronization signal at a second candidate location on the second beam.

[0137] Although not shown in detail, any device or apparatus forming part of the network may include at least a processor, a storage unit, and a communication interface, wherein the processor unit, storage unit, and communication interface are configured to perform the methods of any aspect of the present invention. Further options and choices are described below.

[0138] The signal processing functions of embodiments of the present invention, particularly the gNB and UE, can be implemented using computing systems or architectures known to those skilled in the art. Computing systems such as desktop, laptop, or notebook computers, handheld computing devices (PDAs, cellular phones, PDAs, etc.), mainframes, servers, clients, or any other type of dedicated or general-purpose computing device that may be desired or suitable for a given application or environment can be used. The computing system may include one or more processors, which can be implemented using general-purpose or dedicated processing engines (e.g., microprocessors, microcontrollers, or other control modules).

[0139] The computing system may also include main memory, such as random access memory (RAM) or other dynamic memory, for storing instructions and information to be executed by the processor. Such main memory may also be used to store temporary variables and other intermediate information to be executed by the processor during instruction execution. Similarly, the computing system may include read-only memory (ROM) or other static storage devices for storing static information and instructions for the processor.

[0140] The computing system may further include an information storage system, which may include, for example, a media drive and a removable storage interface. The media drive may include a drive or other mechanism to support fixed or removable storage media, such as a hard disk drive, floppy disk drive, magnetic tape drive, optical disc drive, compact disc (CD) or digital video drive (DVD) read or write drive (R or RW), or other removable or fixed media drive. The storage medium may include, for example, a hard disk, floppy disk, magnetic tape, optical disc, CD or DVD, or other fixed or removable media read or written by a media drive. The storage medium may include a computer-readable storage medium having specific computer software or data stored therein.

[0141] In alternative embodiments, the information storage system may include other similar components for allowing computer programs or other instructions or data to be loaded into the computing system. Such components may include, for example, removable storage units and interfaces, such as program boxes and box interfaces, removable memory (e.g., flash memory or other removable memory modules) and memory slots, as well as other removable storage units and interfaces that allow software and data to be transferred from the removable storage units to the computing system.

[0142] The computing system may also include a communication interface. Such a communication interface can be used to allow software and data to be transferred between the computing system and external devices. Examples of communication interfaces may include modems, network interfaces (such as Ethernet or other NIC cards), communication ports (such as, for example, Universal Serial Bus (USB) ports), PCMCIA slots and cards, and so on. Software and data transmitted via the communication interface are in the form of signals, which may be electrical, electromagnetic, and optical signals, or other signals that can be received by the communication interface medium.

[0143] In this document, the terms "computer program product," "computer-readable medium," etc., can generally be used to refer to tangible media, such as memory, storage devices, or storage units. These and other forms of computer-readable media can store one or more instructions for use by a processor, including a computer system, to cause the processor to perform specified operations. Such instructions, generally referred to as "computer program code" (which may be grouped as computer programs or otherwise), when executed, enable a computing system to perform the functions of embodiments of the present invention. Note that the code may directly cause the processor to perform specified operations, be compiled to do so, and / or be combined with other software, hardware, and / or firmware elements (e.g., libraries for performing standard functions) to do so.

[0144] The non-transitory computer-readable medium may include at least one of the group consisting of: hard disks, CD-ROMs, optical storage devices, magnetic storage devices, read-only memory, programmable read-only memory, erasable programmable read-only memory, electrically erasable programmable read-only memory, and flash memory. In embodiments where the elements are implemented using software, the software may be stored in the computer-readable medium and loaded into the computing system, for example, using a removable storage drive. The control module (in this example, software instructions or executable computer program code), when executed by a processor in the computer system, causes the processor to perform the functions of the invention as described herein.

[0145] Furthermore, the concepts of this invention can be applied to any circuit used to perform signal processing functions within a network element. It is further foreseeable that, for example, semiconductor manufacturers can utilize these concepts when designing stand-alone devices and / or any other subsystem elements such as application-specific integrated circuits (ASICs) or digital signal processors (DSPs).

[0146] It will be appreciated that, for clarity, the above description has referred to embodiments of the invention with reference to a single processing logic. However, the inventive concept can also be implemented by a number of different functional units and processors to provide signal processing functionality. Therefore, references to specific functional units should be considered merely as references to appropriate means for providing the described functionality, and not as indications of a strict logical or physical structure or organization.

[0147] Various aspects of the invention can be implemented in any suitable form, including hardware, software, firmware, or any combination thereof. The invention can optionally be implemented, at least in part, as computer software running on one or more data processors and / or digital signal processors, or as configurable modular components such as FPGA devices.

[0148] Therefore, the elements and components of embodiments of the present invention can be implemented physically, functionally, and logically in any suitable manner. In fact, the functionality can be implemented in a single unit, in multiple units, or as part of other functional units. Although the invention has been described in conjunction with some embodiments, it is not intended to be limited to the specific forms set forth herein. Rather, the scope of the invention is defined only by the appended claims. Furthermore, although certain features have been described in conjunction with specific embodiments, those skilled in the art will recognize that different features of the described embodiments can be combined according to the invention. In the claims, the term "comprising" does not exclude the presence of other elements or steps.

[0149] Furthermore, although listed individually, multiple means, elements, or method steps may be implemented by a single unit or processor. Additionally, while a single feature may be included in different claims, these may also be advantageously combined, and including a feature in different claims does not imply that such a combination is not feasible and / or advantageous. Moreover, including a feature in a claim of one class does not imply limitation to that class, but rather indicates that the feature is equally applicable to other claim classes where appropriate.

[0150] Furthermore, the order of features in the claims does not imply a specific order in which any feature must be performed, and in particular, the order of individual steps in a method claim does not imply that the steps must be performed in that order. Rather, the steps can be performed in any suitable order. Moreover, singular references do not exclude plurals. Therefore, references to “a,” “first,” “second,” etc., do not exclude plurals.

[0151] Although the invention has been described in conjunction with some embodiments, it is not intended to be limited to the specific forms set forth herein. Rather, the scope of the invention is defined only by the appended claims. Furthermore, although certain features have been described in conjunction with specific embodiments, those skilled in the art will recognize that different features of the described embodiments can be combined according to the invention. In the claims, the term "comprising" does not exclude the presence of other elements.

Claims

1. A method for transmitting SS / PBCH bursts in an OFDM transmission system operating in the frequency range of 2 FR2 and utilizing beam scanning technology, characterized in that, The method includes the following steps: selecting a plurality of start positions for transmitting SS / PBCH bursts, wherein the selection of the plurality of start positions is such that there is at least one OFDM symbol gap between adjacent SS / PBCH bursts; and transmitting a plurality of SS / PBCH bursts, wherein each SS / PBCH burst begins at one of the selected plurality of start positions; The method described herein performs at least 8 microseconds of channel sensing before the transmission of the SS / PBCH burst on the new beam. The duration of the channel sensing is adjusted according to the subcarrier spacing (SCS) used, such that the sensing duration corresponds to 1, 2, 4, and 8 OFDM symbols at SCSs of 120 kHz, 240 kHz, 480 kHz, and 960 kHz, respectively.

2. The method as described in claim 1, characterized in that, The system uses a subcarrier spacing of 120 kHz.

3. The method as described in claim 2, characterized in that, The plurality of start positions are located at OFDM symbol number {4,9,15,20}+28*n, where n=0, 1, ..., 15, and reference symbol index 0 corresponds to the first symbol of the first slot in the half-frame of the transmitted SS / PBCH block.

4. The method as described in claim 2, characterized in that, The plurality of start positions are located at OFDM symbol number {2,8,15,20}+28*n, where n=0, 1, ..., 15, and reference symbol index 0 corresponds to the first symbol of the first slot in the half-frame of the transmitted SS / PBCH block.

5. The method as described in claim 2, characterized in that, The plurality of start positions are located at OFDM symbol number {4,9,15,20}+28*n, where n=0, 1, 2, ..., 19, and reference symbol index 0 corresponds to the first symbol of the first slot in the half-frame of the transmitted SS / PBCH block.

6. The method as described in claim 1, characterized in that, The system uses a subcarrier spacing of 240 kHz.

7. The method as described in claim 6, characterized in that, The plurality of start positions are located at OFDM symbol numbers {8,14, 20, 32, 38, 44}+56*n, where n=0, 1, 2, ..., 10, and reference symbol index 0 corresponds to the first symbol of the first slot in the half-frame of the transmitted SS / PBCH block.

8. The method as described in claim 6, characterized in that, The plurality of start positions are located at OFDM symbol numbers {8,14, 20, 32, 38, 44}+56*n, where n=0, 1, 2, ..., 19, and reference symbol index 0 corresponds to the first symbol of the first slot in the half-frame of the transmitted SS / PBCH block.

9. The method as described in claim 6, characterized in that, The plurality of start positions are located at OFDM symbol number {8,16, 32, 44}+56*n, where n=0, 1, 2, ..., 15, and reference symbol index 0 corresponds to the first symbol of the first slot in the half-frame of the transmitted SS / PBCH block.

10. The method as described in claim 6, characterized in that, The plurality of start positions are located at OFDM symbol number {8,16, 32, 44}+56*n, where n=0, 1, 2, ..., 19, and reference symbol index 0 corresponds to the first symbol of the first slot in the half-frame of the transmitted SS / PBCH block.

11. The method as described in claim 1, characterized in that, The system uses a subcarrier spacing of 480 kHz.

12. The method as described in claim 11, characterized in that, The plurality of start positions are located at OFDM symbol number {4,12, 20}+28*n, where n=0, 1, 2, ..., 21, and reference symbol index 0 corresponds to the first symbol of the first slot in the half-frame of the transmitted SS / PBCH block.

13. The method as described in claim 11, characterized in that, The plurality of start positions are located at OFDM symbol numbers {16, 32, 40, 64, 72, 88} + 112*n, where n = 0, 1, 2, ..., 10, and reference symbol index 0 corresponds to the first symbol of the first slot in the half-frame of the transmitted SS / PBCH block.

14. The method as described in claim 1, characterized in that, The system uses a subcarrier spacing of 960 kHz.

15. The method as described in claim 14, characterized in that, The plurality of start positions are located at OFDM symbol number {8,20,32,44}+56*n, where n=0, 1, 2, ..., 15, and reference symbol index 0 corresponds to the first symbol of the first slot in the half-frame of the transmitted SS / PBCH block.

16. The method as described in claim 14, characterized in that, The plurality of start positions are located at OFDM symbol numbers {32, 44, 64, 76, 88, 128, 144, 156, 176, 188} + 224*n, where n = 0, 1, 2, ..., 6, and reference symbol index 0 corresponds to the first symbol of the first slot in the half-frame of the transmitted SS / PBCH block.

17. The method as described in any one of the preceding claims, characterized in that, It also includes the step of sending instructions for the plurality of starting positions.

18. The method as described in claim 17, characterized in that, The multiple starting positions are transmitted using the PBCH payload.

19. The method as described in claim 18, characterized in that, Reserved bits of the MIB payload are used as part of the indication of the plurality of start positions.

20. The method as described in claim 17, characterized in that, The number of the plurality of starting positions shall not exceed 128.

21. The method as described in claim 17, characterized in that, PBCH DMRS indicates at least a portion of the plurality of starting positions.

22. The method as described in claim 17, characterized in that, The multiple starting positions are indicated by the SS / PBCH candidate index.

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