WO2026000119A1

WO2026000119A1 - A method of initial access

Info

Publication number: WO2026000119A1
Application number: PCT/CN2024/100998
Authority: WO
Inventors: Chenmeng LI; Wen Tang; Chien-Hwa Hwang; Min LEI; Tao Chen
Original assignee: MediaTek Singapore Pte Ltd
Current assignee: MediaTek Singapore Pte Ltd
Priority date: 2024-06-24
Filing date: 2024-06-24
Publication date: 2026-01-02
Anticipated expiration: 2026-12-24
Also published as: WO2026001536A1

Abstract

In 5G NR, the initial access procedure is designed to enable a new user equipment (UE) to establish a connection with the network, acquire synchronization, and obtain the necessary resources to initiate communication. However, in the context of various scenarios, the unique characteristics of satellite communication, green radio communication and etc., pose challenges that require specific enhancements to the initial access procedure. This disclosure addresses these challenges by proposing initial access methods optimized for different communication scenarios, ensuring efficient and reliable communication. In light of this situation, a method of initial access is proposed in this disclosure, including the SSB design with SSB beam index, SSB repetition index and new SSB index, the SSS structure, the beam index and repetition index carry method, the time boundary information carry and calculation method, the different SSB structure for various scenarios, and the SSB repetition structure within a SSB beam duration.

Description

A METHOD OF INITIAL ACCESS

FIELD

The invention discussed below relates generally to wireless communication, and more particularly, to methods for initial access.

BACKGROUND

In 5G NR, the initial access procedure is designed to enable a new user equipment (UE) to establish a connection with the network, acquire synchronization, and obtain the necessary resources to initiate communication. However, in the context of various scenarios, the unique characteristics of satellite communication, green radio communication and etc., pose challenges that require specific enhancements to the initial access procedure. This disclosure addresses these challenges by proposing initial access methods optimized for different communication scenarios, ensuring efficient and reliable communication between satellites/BS/gNBs/eNBs/etc and UEs in the communication network.

In light of this situation, it is necessary to design different synchronization signal and information to enhance the signal-to-noise ratio for user equipment reception. This disclosure proposes a method for enabling user equipment to obtain the synchronization signal and information.

SUMMARY

The following presents a simplified summary of one or more aspects in order to provide a basic understanding of such aspects. This summary is not an extensive overview of all contemplated aspects, and is intended to neither identify key or critical elements of all aspects nor delineate the scope of any or all aspects. Its sole purpose is to present some concepts of one or more aspects in a simplified form as a preclude to the more detailed description that is presented later.

In one aspect, the method of SSB design with SSB beam index, SSB repetition index and new SSB index is proposed. The SSB is transmitted via different beams of the transmitter. Multiple SSB repetitions (e.g., R repetitions) is transmitted via the same beam with the same beam index. Multiple beams (e.g., N beams) is transmitted within a SSB periodicity.

In another aspect, the method of SSS structure is proposed. The multiple SSS repetitions is within a SSB. The SSS is multiplexing with the PBCH. The SSS is either a long sequency multiplexing with a PBCH or a short sequence with repetitions multiplexing with a PBCH.

In another aspect, the beam index and repetition index carry method is proposed. The information is carried via PSS/SSS phase, PSS/SSS/cell ID, sync assisting signal (SAS) or Initial Access Assistance Signal (IAAS) , etc. and is either pre-configured or pre-defined.

In another aspect, the method of time boundary information carry and calculation method is proposed for both flexible and non-flexible SSB configuration type.

In another aspect, the method of different SSB structure for various scenarios is proposed. More specifically, SSB repetition with 5 symbols and 22 PRBs and SSB repetition with 5 symbols and 16 PRBs are proposed.

In another aspect, the method of SSB repetition structure within a SSB beam duration is proposed. The structure of the SSB repetitions within a SSB beam duration can be the same or different, the time gap between the starting symbol of SSB repetitions can be the same or different.

To the accomplishment of the foregoing and related ends, the one or more aspects comprise the features hereinafter fully described and particularly pointed out in the claims. The following description and the annexed figures set forth in detail certain illustrative features of the one or more aspects. These features are indicative, however, of but a few of the various ways in which the principles of various aspects may be employed, and this description is intended to include all such aspects and their equivalents.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates an exemplary diagram of the relationship of SSB beam index, SSB repetition index and SSB periodicity.

FIG. 2 illustrates an exemplary diagram of SSB pattern of SSS option 1 with R=4.

FIG. 3 illustrates an exemplary diagram of SSB pattern of SSS option 2 with R=2.

FIG. 4 illustrates an exemplary diagram of SSB pattern within a SSB beam duration of different SSB repetition structure.

FIG. 5 illustrates an exemplary diagram of SSB structure 1.

FIG. 6 illustrates an exemplary diagram of SSB structure 2.

FIG. 7 illustrates an exemplary diagram of SSB structure 3/5.

FIG. 8 illustrates an exemplary diagram of SSB structure 4.

DETAILED DESCRIPTION

The detailed description set forth below in connection with the appended drawings is intended as a description of various configurations and is not intended to represent the only configurations in which the concepts described herein may be practiced. The detailed description includes specific details for the purpose of providing a thorough understanding of various concepts. However, it will be apparent to those skilled in the art that these concepts may be practiced without these specific details. In some instances, well known structures and components are shown in block diagram form in order to avoid obscuring such concepts.

Several aspects of telecommunication systems will now be presented with reference to various apparatus and methods. These apparatus and methods will be described in the following detailed description and illustrated in the accompanying drawings by various blocks, components, circuits, processes, algorithms, etc. (collectively referred to as “elements” ) . These elements may be implemented using electronic hardware, computer software, or any combination thereof. Whether such elements are implemented as hardware or software depends upon the particular application and design constraints imposed on the overall system.

Before this disclosure, it should be noted that the SSB mentioned in the following alternatives including but not limited to PSS, SSS, PBCH, and the SSB structure can be different from the NR SSB structure.

In one aspect of the disclosure, the method of synchronization signal and information block (SSB) structure design is proposed. More specifically, we propose to consider the following alternative:

Alternative#1: SSB design

1. SSB repetition index:

a) definition: for each transmitter beam, there are multiple SSB repetitions within the beam duration (e.g., R repetitions for each transmitter beam) . The SSB repetition number R is either the same or different for each transmitter beam.

b) Rmax: a Rmax can be (pre-) configured or (pre-) defined to describe the max value of SSB repetition number within a transmitter SSB beam duration. In case of the transmitter capability and communication scenario difference, the transmitter/network can choose not to transmit Rmax SSB repetitions, for example, choose to transmit R (R<=Rmax) SSB beams.

2. SSB beam index:

a) definition: there are multiple SSB transmitter beams within a SSB periodicity (e.g., N beams within a SSB periodicity) . The SSB transmitter beams N is either the same or different for each frequency band and/or earth geographical location.

b) Nmax: a Nmax can be (pre-) configured or (pre-) defined to describe the max value of SSB beam number within a SSB periodicity. In case of the transmitter capability and communication scenario difference, the transmitter/network can choose not to transmit Nmax SSB beams, for example, choose to transmit N (N<=Nmax) SSB beams within a SSB periodicity.

3. New SSB index:

a) definition: there are multiple SSBs repetitions and different SSBs for different beam index within a SSB periodicity, a certain SSB can be identified by the new SSB index to describe which SSB it is within the SSB periodicity.

Note for alternative 1:

- the value Rmax and Nmax is either pre-configured (via SAS/IAAS, PSS/SSS phase, etc. ) or pre-defined for different bands and/or systems. The pre-configure or pre-define method of Rmax and Nmax is not necessarily the same.

- for example, as is shown in figure 1, the relationship of SSB beam index (e.g., Beam_SSB_set#0, Beam_SSB_set#1, etc. ) , SSB repetition index (e.g., SSB_rep#0, SSB_rep#1, etc. ) and SSB periodicity is illustrated.

- the SSB repetitions within a SSB beam duration is not necessarily the same;

- the payload of PBCH within each SSB between different SSB beam duration is different, i.e., the SSB beam index is different

- the SSB beam index info is carried by one or multiple of the following:

■ PBCH payload

■ PSS/SSS ID

■ PSS/SSS ID generation method

■ PSS/SSS ID pattern in time domain

- The new SSB index of each SSB within the SSB periodicity is different

■ The new SSB index can be assigned according to the actual SSB transmitted times R and N or the Rmax and/or Nmax

In another aspect of the disclosure, the method of SSS structure is proposed. More specifically, we propose to consider the following alternative:

Alternative#2: SSS structure

Option 1:

- a long sequence (e.g., LDPB sequence, gold sequence, m sequence, pseudo random sequence, etc. ) multiplexing with a PBCH of 3 symbols in frequency domain, i.e., each SSS is throughout the 3 symbols at the same time of PBCH duration. The gap M between the SSS REs in frequency domain for each symbol can be (pre-) configured or (pre-) defined (e.g., M=3, M=4, etc. ) . The SSS sequence can be evenly or unevenly distributed throughout the frequency and/or time domain.

- For example, as is illustrated in figure 2, the SSS length is 255 RE, and is multiplexing with the PBCH of 3 symbols in frequency domain. There are 4 SSB repetitions within a SSB beam duration, i.e. R=4.

Option 2:

- a short sequence (e.g., LDPB sequence, gold sequence, m sequence, pseudo random sequence, etc. ) multiplexing with each PBCH symbol in frequency domain, i.e., each SSS occupies only 1 symbol at the same time of PBCH duration. The gap M between the SSS REs in frequency domain for each symbol can be (pre-) configured or (pre-) defined (e.g., M=3, M=4, etc. ) . The SSS sequence can be evenly or unevenly distributed throughout the frequency and/or time domain.

- For example, as is illustrated in figure 3, the SSS length is 63 RE, and is multiplexing with the PBCH of 3 symbols in frequency domain. There are 3 SSS repetitions within a SSB repetition. There are 2 SSB repetitions within a SSB beam duration , i.e. R=2.

Note for alternative 2:

- According to the R of each SSB beam duration, the PSS/SSS/PBCH repetition number may different between SSB beams, transmitters or networks, and/or frequency bands.

- The SSS sequence length can be 63, 216, 127, 255 and etc.

In another aspect of the disclosure, the SSB beam index and SSB repetition index carry method is proposed. More specifically, we propose to consider the following alternative:

Alternative#3: SSB beam index and SSB repetition index carry method

SSB repetition index: the SSB repetition index within a SSB beam duration can be carried by at least one of the followings, and is either pre-configured or pre-defined:

- PSS/SSS sequence phase

■ For example, the PSS and/or SSS sequence of the different SSB repetitions would multiply with a different phase adjustment factor V. Assuming there are 2 PSS repetitions per SSB repetition and R=4 SSB repetitions, then the 2 PSS repetitions within each SSB repetition can multiply with V1= {1, 1} , V2= {1, -1} , V3= {-1, 1} , V4= {-1, -1} respectively in frequency domain, to indicate the SSB repetition index 0, 1, 2 and 3. Assuming there are 3 SSS repetitions per SSB repetition and R=4 SSB repetitions, then the 2 PSS repetitions within each SSB repetition can multiply with V1= {1, 1, 1} , V2= {1, 1, -1} , …, V8= {-1, -1, -1} respectively in frequency domain, to indicate the SSB repetition index 0, 1, 2, …, and 7.

SSB beam index: the SSB beam index within a SSB periodicity can be carried by at least one of the followings, and is either pre-configured or pre-defined:

- Carried by PBCH payload

- PSS/SSS/cell ID

■ If there are 1008 cell IDs in total, then the different set of cell IDs, and the corresponding PSS/SSS (s) sequences, can indicate the SSB beam index. For example, cell ID ∈ {0, 1, …, 336} for beam index 1, cell ID ∈ {337, 338, …, 672} for beam index 2, and etc..

- Synchronization assisting signal (SAS) or Initial Access Assistance Signal (IAAS)

■ The Synchronization assisting signal (SAS) or Initial Access Assistance Signal (IAAS) is transmitted by satellite and/or network and detected by UEs at the beginning of UE initial cell search, or before initial cell search. The SAS is a always-on signal that is broadcast to all the UEs and is independent from the SSB (e.g., PSS, SSS, PBCH, etc. ) . Information can be carried by different SAS repetition pattern in time domain, phase adjustment in frequency domain, and etc.

■ The SSB beam index can be carried by SAS/IAAS via at least one of the followings:

◆ Different sequence;

◆ Different cyclic-shift of the sequence;

◆ Different occupying symbols /SAS repetition pattern within a periodicity in time domain;

◆ Different power boosting pattern;

◆ Different phase adjustment in frequency domain for different repetitions within a SAS periodicity, and/or for different repetitions cross SAS periodicities;

Note for alternative 3:

- If the phase adjustment factor is V= {1, -1} for the 2 PSS/SSS repetitions within a SSB repetition, and the original signal (PSS or SSS) in frequency domain is S, then the signal multiply with the phase adjustment factor is {S, -S} .

- Each SSB repetition within a SSB beam duration has the same SSB beam index.

In another aspect of the disclosure, the method of time boundary information carry and calculation method is proposed for both flexible and non-flexible synchronization signal and information block configuration type. More specifically, we propose to consider the following alternative:

Alternative#4: time boundary information carry and calculation method

For flexible SSB configuration type:

- flexible SSB configuration type: If the transmitter has transmitted only at some of the SSB repetition occasions (i.e., R<Rmax) , then the transmitter will have different SSB repetition num R within a SSB beam duration, which lead to different SSB beam time durations within a SSB periodicity.

- The time boundary of the SSB periodicity:

■ The time boundary can be represented as: where T0 is the detected timing (e.g., the start symbol/slot/etc. ) of the current SSB repetition, SSBbeam_idx∈ {0, 1, …, N_max- 1} , (SSBbeam_idx) is the time duration of the SSBbeam_idx-th SSB beam which may include multiple SSB repetitions (e.g., the granularity of the the time duration can be slots, symbols, subframes and etc. ) , SSBrep_idx∈ {0, 1, …, R_max-1} is index of the current detected SSB repetition within a SSB beam, is the time duration of a single SSB repetition within a SSB beam which may includes multiple PSS/SSS/PBCH repetitions (e.g., the granularity of the the time duration can be slots, symbols and etc. ) .

For non-flexible SSB configuration type:

- Non-flexible SSB configuration type: The transmitter only transmits a max fixed SSB repetitions number within all the SSB beam duration (i.e., R=Rmax) , which lead to the same SSB beam time durations within a SSB periodicity.

- The time boundary of the SSB periodicity:

■ The time boundary can be represented as: where (SSBbeam_idx) for all the SSBbeam_idx∈ {0, 1, …, N_max-1} is the same.

Note for alternative 4:

- the max SSB repetition number Rmax within a SSB beam duration is a fixed and pre-defined (or pre-configured) value, which means the SSB beam max time duration is a fixed value.

- The time boundary of the SSB periodicity represents for the start of the symbol/slot/subframe of the first SSB repetition within the first SSB beam duration within a SSB periodicity.

- It is not necessary to have the same Rmax and/or Nmax for all the scenarios.

- In case of flexible SSB configuration type and the real R for each SSB beam duration is unknown, RSRP detection can be adopted to check if the SSB repetition occasion has a corresponding SSB repetition transmitting.

In another aspect of the disclosure, the method of different SSB structure for various scenarios is proposed. More specifically, we propose to consider the following alternative:

Alternative#5: SSB structure

Structure 1: 5 symbols and 22 PRBs (as is shown in Fig. 5)

- PSS: 2 PSS repetitions, each repetition occupies one symbol

- SSS and PBCH:

■ Option 1: single SSS, occupies 3 symbols with SSS sequence length of 255; single PBCH through out 3 symbols, occupies 516 REs

◆ For 5 symbols and 22 PRBs

■ Option 2: 3 SSS repetitions, each SSS occupies 1 symbol with SSS sequence length of 63; single PBCH through out 3 symbols, occupies 576 REs

■ Option 3: 2 SSS repetitions, each SSS occupies 1 symbol with SSS sequence length of 127; single PBCH through out 3 symbols, occupies 511 REs

Structure 2: 6 symbols and 16 PRBs (as is shown in Fig. 6)

■ Option 1: 2 PSS repetitions, each repetition occupies one symbol; single SSS occupies 4 symbols with SSS sequence length 255; single PBCH through out 4 symbols with 513 REs

■ Option 2: 2 PSS repetitions, each repetition occupies 1 symbol; 4 SSS repetitions, each SSS occupies 1 symbol with SSS sequence length 63; single PBCH through out 4 symbols with 16*12*4-63*4-4=512 REs

■ Option 3: 2 PSS repetitions, each repetition occupies 1 symbol; 3 SSS repetitions, each SSS occupies 1 symbol with SSS sequence length of 63; single PBCH through out 4 symbols with 16*12*4-63*3-4=575 REs

■ Option 4: 2 PSS repetitions, each repetition occupies 1 symbol; 2 SSS repetitions, each SSS occupies 2 symbols with SSS sequence length of 127; single PBCH through out 4 symbols with 16*12*4-127*2-4=510 REs

Structure 3: 28 symbols and 22 PRBs (as is shown in Fig. 7)

■ PSS : PSS*R1 occupies R1 symbols (e.g., R1=8 is predefined)

■ SSS and PBCH multiplexing

◆ R2 SSS and PBCH block repetitions.

◆ Reuse the SSS and PBCH block RE mapping options from Structure 1

Structure 4: 4 symbols and 16 PRBs (as is shown in Fig. 8)

■ PSS : occupies 1 symbol

■ SSS and PBCH multiplexing

◆ Option 1: 1 PSS occupies 1 symbol; 2 SSS repetitions, each SSS occupies 1 symbol with SSS sequence length of 63; single PBCH through out 3 symbols with 16*12*3-63*2-3=446 REs

◆ Option 2: 1 PSS occupies 1 symbol; 3 SSS repetitions, each SSS occupies 1 symbol with SSS sequence length of 31; single PBCH through out 3 symbols with 16*12*3-31*3-3=479 REs

Structure 5: 28 symbols and 16 PRBs (as is shown in Fig. 7)

■ PSS : PSS*R1 occupies R1 symbols (e.g., R1=8 is predefined)

■ SSS and PBCH multiplexing

◆ R2 SSS and PBCH block repetitions.

◆ Reuse the SSS and PBCH block RE mapping options from Structure 2 or Structure 4

Note for alternative 5:

- The SSS is multiplexing with PBCH in frequency domain;

- The PSS is either LDPB sequence, M sequence, Gold sequence, or any other sequence with good correlation property with length of 127, 133, 183 or any other length.

- The PSS and SSS/PBCH symbol order is flexible and not confined within a certain order.

- The alternative above only specified the sequence length of PSS and SSS, the occupied RE numbers of PBCH, and the time and frequency resource of a SSB, the specific sequence of PSS/SSS or the modulation method of PBCH is not restricted.

- For SSB structure 3 and 5: the R1 PSS repetitions is either continuous or non-continuous

- For SSB structure 2 and 5: for beam sweeping within one SSB periodicity : Maximum R2 SSS and PBCH block repetition numbers for one beam is pre-configured, and R1 PSS repetition number for one beam is predefined

- For the case of PBCH and SSS block didn’t occupy all the 22 or 16 PRBs (i.e., still some REs left unmapped) in the alternatives above, the REs can be mapped with PBCH.

In another aspect of the disclosure, the method of SSB repetition structure within a SSB beam duration is proposed. More specifically, we propose to consider the following alternative:

Alternative#6: SSB repetition structure within a SSB beam duration

SSB repetition structure:

- Option 1: each SSB repetition within a SSB beam duration is the same

- Option 2: each SSB repetition within a SSB beam duration is the different

■ For example, as is shown in Figure 4, the SSB repetition 0/1/2/3 within a SSB beam duration has different structure, i.e., with different PSS and SSS/PBCH symbol order

Time gap between the starting symbol of SSB repetitions:

- Option 1: is the same

■ For example, the starting symbol index of the SSB repetitions is {1 or 8} +n, where n is the slot index, n=0, 1, 2, … (i.e., the gap is 7 symbols)

- Option 2: is different

■ For example, the starting symbol index of the SSB repetitions is {1 or 9} +n, where n is the slot index, n=0, 1, 2, … (i.e., the gap is 6 or 8 symbols)

Note for alternative 6:

- In case of option 2, the PSS/SSS signal and PBCH payload within each SSB repetition is the same.

- In case of option 2, the SSB structure is related to the SSB repetition indexSSBrep_idx∈ {0, 1, …, R_max-1} . For example, the 1^st SSB repetition will be SSB structure 1, the 2^nd SSB repetition will be SSB structure 2, and etc..

In another aspect of the disclosure, the SSB repetition number indicating method of PSS ID within a SSB beam duration is proposed. More specifically, we propose to consider the following alternative:

Alternative#7: SSB repetition number indicating method of PSS ID within a SSB beam duration

- The SSB repetition number is related with the PSS ID. Different (set of) PSS ID (s) (i.e., cellid2) is assigned to different SSB repetition numbers, thus the UE will know the SSB repetition numbers by using different combination number and PSS IDs.

Note for Alternative 7:

- For example, the SSB repetition number 1, 2, 3, 4 can be assigned PSS ID 0, 1, 2, 3 respectively, or the SSB repetition number 1, 2, 3, 4 can be assigned PSS ID {0, 1, 2} , {3, 4, 5} , {6, 7, 8} , {9, 10, 11} , or other similar combinations.

- For example, the UE will first use PSS ID {0, 1, 2} to detect SSB, then use PSS ID {3, 4, 5} and 2 SSB combine in time domain to detect SSB, then use PSS ID {6, 7, 8} and 3 SSB combine in time domain to detect SSB, then use PSS ID {9, 10, 11} and 4 SSB combine in time domain to detect SSB.

- The certain SSB repetition number can be decided by the network/Satellite/BS according to different scenarios.

In another aspect of the disclosure, the information bit carry method of PSS phase is proposed. More specifically, we propose to consider the following alternative:

Alternative#8: information bit carry method of DBPSK

To utilize the phase difference of PSS correlation output to conveying information, the method of differential binary phase shift keying (DBPSK) is proposed. For instance, let’s designate the phase of the n-th PSS correlation output as θ_n, where 0≤n≤P-1. If -π/2<θ_n+1-θ_n<π/2, then the bit b_n=0; otherwise, b_n=1. This approach enables us to transmit P-1 bits. Note for Alternative 8:

- The PSS symbol is consecutive or non-consecutive;

- The information bit and θ_n+1-θ_n mapping rule is not confined within the instance above, other mapping rule is also considered.

- The phase difference of PSS correlation output and the phase of PSS correlation output activate at the same time is not precluded.

The previous description is provided to enable any person skilled in the art to practice the various aspects described herein. Various modifications to these aspects will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other aspects. Thus, the claims are not intended to be limited to the aspects shown herein, but is to be accorded the full scope consistent with the language claims, wherein reference to an element in the singular is not intended to mean “one and only one” unless specifically so stated, but rather “one or more. ” The word “exemplary” is used herein to mean “serving as an example, instance, or illustration. ” Any aspect described herein as “exemplary” is not necessarily to be construed as preferred or advantageous over other aspects. Unless specifically stated otherwise, the term “some” refers to one or more. Combinations such as “at least one of A, B, or C, ” “one or more of A, B, or C, ” “at least one of A, B, and C, ” “one or more of A, B, and C, ” and “A, B, C, or any combination thereof” include any combination of A, B, and/or C, and may include multiples of A, multiples of B, or multiples of C. Specifically, combinations such as “at least one of A, B, or C, ” “one or more of A, B, or C, ” “at least one of A, B, and C, ” “one or more of A, B, and C, ” and “A, B, C, or any combination thereof” may be A only, B only, C only, A and B, A and C, B and C, or A and B and C, where any such combinations may contain one or more member or members of A, B, or C. All structural and functional equivalents to the elements of the various aspects described throughout this disclosure that are known or later come to be known to those of ordinary skill in the art are expressly incorporated herein by reference and are intended to be encompassed by the claims. Moreover, nothing disclosed herein is intended to be dedicated to the public regardless of whether such disclosure is explicitly recited in the claims. The words “module, ” “mechanism, ” “element, ” “UE, ” and the like may not be a substitute for the word “means. ” As such, no claim element is to be construed as a means plus function unless the element is expressly recited using the phrase “means for. ”

While aspects of the present disclosure have been described in conjunction with the specific embodiments thereof that are proposed as examples, alternatives, modifications, and variations to the examples may be made. Accordingly, embodiments as set forth herein are intended to be illustrative and not limiting. There are changes that may be made without departing from the scope of the claims set forth below.

Claims

A method of initial access, wherein the method is used by a user equipment.
The method of claim 1, wherein the synchronization signal and information block (SSB) structure design.
The method of claim 2, wherein the multiple SSB repetitions with SSB repetition index are within a SSB beam, multiple SSB beams with SSB beam index are within a SSB periodicity.
The method of claim 2, wherein the a Rmax is to describe the max value of SSB repetition number within a SSB beam duration, the real transmitted SSB repetition number is R (R<=Rmax) .
The method of claim 2, wherein the Nmax is to describe the max value of SSB beam number within a SSB periodicity the real transmitted SSB beam number is N (N<=Nmax) .
The method of claim 2, wherein the certain SSB repetition can be identified by the new SSB index to describe which SSB repetition it is within the SSB periodicity of all the beams.
The method of claim 2, wherein the Rmax and Nmax is either pre-configured or pre-defined for different bands and/or systems and the pre-configure or pre-define method of Rmax and Nmax is not necessarily the same for different band/scenarios/satellite/beams/geographical area/etc.
The method of claim 1, wherein the method includes the SSS structure.
The method of claim 8, wherein the SSS is a long sequence or several short sequence repetitions multiplexing with a single PBCH of multiple symbols in frequency domain.
The method of claim 8, wherein the gap M REs between the SSS REs in frequency domain for each symbol are (pre-) configured or (pre-) defined.
The method of claim 1, wherein the SSB beam index and SSB repetition index carry method.
The method of claim 11, wherein the SSB repetition index within a SSB beam duration can be carried by at least one of the followings, and is either pre-configured or pre-defined:

nPSS/SSS sequence phase

nPBCH payload

nPSS/SSS/cell ID

nSynchronization assisting signal (SAS) or Initial Access Assistance Signal (IAAS) .
The method of claim 1, wherein the time boundary information carry and calculation method.
The method of claim 13, wherein the time boundary information carry and calculation method for flexible and non-flexible SSB configuration type, the time boundary can be represented as: where T0 is the detected timing (e.g., the start symbol/slot/s/ms/etc. ) of the current SSB repetition, SSBbeam_idx∈ {0, 1, …, N_max-1} , (SSBbeam_idx) is the time duration of the SSBbeam_idx-th SSB beam which may include multiple SSB repetitions (e.g., the granularity of the the time duration can be slots, symbols, subframes and etc. ) , SSBrep_idx∈ {0, 1, …, R_max-1} is index of the current detected SSB repetition within a SSB beam, is the time duration of a single SSB repetition within a SSB beam which may include multiple PSS/SSS/PBCH repetitions.
The method of claim 13, wherein the (SSBbeam_idx) for all the SSBbeam_idx∈ {0, 1, …, N_max-1} is the same for non-flexible SSB configuration type, and the(SSBbeam_idx) for all the SSBbeam_idx∈ {0, 1, …, N_max-1} is different for flexible SSB configuration type.
The method of claim 1, wherein the different SSB structure for various scenarios.
The method of claim 16, wherein the SSB structure 1 to 5.
The method of claim 1, wherein the SSB repetition structure within a SSB beam duration.
The method of claim 18, wherein the time gap between the starting symbol of SSB repetitions is the same or different, and the SSB repetition structure is:

a.Option 1: each SSB repetition within a SSB beam duration is the same,

b.Option 2: each SSB repetition within a SSB beam duration is the different.
The method of claim 1, wherein the SSB repetition number indicating method within a SSB beam duration via different PSS ID.