WO2025175441A1

WO2025175441A1 - Enhancement method for a downlink channel

Info

Publication number: WO2025175441A1
Application number: PCT/CN2024/077634
Authority: WO
Inventors: Yiwei DENG; Yu Ding; Kai Liu; Shahid JAN
Original assignee: Shenzhen TCL New Technology Co Ltd
Current assignee: Shenzhen TCL New Technology Co Ltd
Priority date: 2024-02-19
Filing date: 2024-02-19
Publication date: 2025-08-28
Anticipated expiration: 2026-08-19

Abstract

An enhancement method for a downlink (DL) channel is provided. The method is executed by a base station. The method includes: transmitting an information of the DL channel; and transmitting at least one repetition of the information of the DL channel. Since a set of downlink channels of a communication system may be coverage bottleneck channels, the implementation of the present disclosure may improve coverage capacity of the communication system.

Description

ENHANCEMENT METHOD FOR A DOWNLINK CHANNEL

TECHNICAL FIELD

The present disclosure generally relates to communication coverage enhancement technology, and in particular to an enhancement method for a downlink (DL) channel, a communication device and a computer readable media.

BACKGROUND

Coverage is a key factor that operators consider when commercializing cellular communication networks due to its direct impact on service quality as well as cost. Despite the importance of coverage for the success of NR (New Radio) commercialization, a comprehensive coverage evaluation and comparison with legacy Radio Access Technologies (RATs) , considering all NR specification details, have not been conducted up to now.

Compared to LTE, NR is designed to operate at much higher frequencies, such as 28 GHz or 39 GHz in FR2 (Frequency Range 2) . Furthermore, many countries are making more spectrum available in FR1 (Frequency Range 1) , such as 3.5 GHz, which is typically at higher frequencies than those used for LTE or 3G. Due to these higher frequencies, the wireless channel will inevitably be subject to higher path loss, making it more challenging to maintain an adequate quality of service that is at least equal to that of legacy RATs. One key mobile application of particular importance is voice service, for which a typical subscriber will always expect ubiquitous coverage wherever they are.

For FR1, NR can be deployed either in newly allocated spectrums, such as 3.5 GHz, or in a spectrum re-farmed from a legacy network, e.g., 3G and 4G. In either case, coverage will be a critical issue, considering the fact that these spectrums will most likely handle key mobile services such as voice and low-rate data services. For FR2, coverage was not thoroughly evaluated during the self-evaluation campaign towards IMT-2020 submission and was not considered in Release 16 enhancements. In this regard, a thorough understanding of NR coverage performance is needed while taking into account the support of the latest NR specifications. Consequently, in Release 17 and Release 18, coverage enhancements for the uplink (UL) channel have been studied. However, enhancements for the downlink channel are yet to be studied.

For example, all satellites for 5G satellite networks, operating in both FR1 and FR2 and covering both Geostationary Orbit (GSO) and Non-Geostationary Orbit (NGSO) constellations, are expected to be designed with optimized power assumptions over the next 10 years. There is a strong need to implement downlink (DL) coverage enhancement techniques to optimize performance and cost for a given targeted coverage. This document primarily focuses on wireless communication between the base station and the user device, for example, in the case of wireless communication under a Non-Terrestrial Network (NTN) .

SUMMARY

Accordingly, the present disclosure aims to provide an enhancement method for a downlink (DL) channel in random access procedure, a communication device and a computer readable media.

A technical scheme adopted by the present disclosure is to provide an enhancement method for a downlink (DL) channel. The method is executed by a base station. The method includes: transmitting an information of the DL channel; and transmitting at least one repetition of the information of the DL channel.

Another technical scheme adopted by the present disclosure is to provide an enhancement method for a downlink (DL) channel. The method is executed by a user equipment (UE) . The method includes: receiving an information of the DL channel; and receiving at least one repetition of the information of the DL channel.

Another technical scheme adopted by the present disclosure is to provide an enhancement method for a downlink (DL) channel. The method is executed by a base station. The method includes: transmitting an information of the DL channel across more than two symbols or slots.

Another technical scheme adopted by the present disclosure is to provide an enhancement method for a downlink (DL) channel. The method is executed by a user equipment (UE) . The method includes: receiving an information of the DL channel across more than two symbols or slots.

Another technical scheme adopted by the present disclosure is to provide a communication device. The communication device includes a transceiver, a processor and a memory. The transceiver is configured to transmit or receive a signal. The memory is configured to store program instruction, which when executed by the processor, causes the processor to perform any of the foregoing methods.

Another technical scheme adopted by the present disclosure is to provide a computer readable media. The computer readable media is configured to store program instructions that, when executed by a processor, cause the processor to perform any of the foregoing methods.

BRIEF DESCRIPTION OF THE DRAWINGS

In order to clearly explain the technical solutions in the embodiments of the present disclosure, the drawings used in the description of the embodiments will be briefly described below. Obviously, the drawings in the following description are merely some embodiments of the present disclosure. For those of ordinary skill in the art, other drawings may also be obtained based on these drawings without any creative work.

FIG. 1 shows a flowchart of a 4-step RACH procedure.

FIG. 2 illustrates time relationship between each channel during random access procedure.

FIG. 3 illustrates an example where repetitions of DCI of SIB1 are introduced according to an embodiment of the present disclosure.

FIG. 4 illustrates an example where DCI of SIB1 is transmitted across multiple symbols according to an embodiment of the present disclosure.

FIG. 5 illustrates an example where a first repetition of MSG2 is utilized for determining time relationship between MSG2 and MSG3 according to an embodiment of the present disclosure.

FIG. 6 illustrates an example where multiple sub-sets of repetitions of MSG2 are utilized for determining time relationship between MSG2 and MSG3 according to an embodiment of the present disclosure.

FIG. 7 illustrates an example where a last repetition of MSG2 is utilized for determining time relationship between MSG2 and MSG3 according to an embodiment of the present disclosure.

FIG. 8 is a flowchart of an enhancement method for a downlink (DL) channel in random access procedure according to an embodiment of the present disclosure.

FIG. 9 is a flowchart of an enhancement method for a downlink (DL) channel in random access procedure according to another embodiment of the present disclosure.

FIG. 10 is a flowchart of an enhancement method for a downlink (DL) channel in random access procedure according to yet another embodiment of the present disclosure.

FIG. 11 is a flowchart of an enhancement method for a downlink (DL) channel in random access procedure according to another embodiment of the present disclosure.

FIG. 12 is a schematic diagram of a communication device according to an embodiment of the present disclosure.

DETAILED DESCRIPTION

The disclosure will now be described in detail with reference to the accompanying drawings and examples. Apparently, the described embodiments are only a part of the embodiments of the present disclosure, not all of the embodiments. All other embodiments obtained by a person of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

In Release 18, uplink (UL) coverage enhancements have been specified as part of New Radio Non-Terrestrial Network (NR NTN) enhancements, such as repetitions and Demodulation Reference Signal (DMRS) bundling. During the NR NTN R18 study phase for coverage enhancement, the link level evaluation identified UL coverage as the bottleneck. However, the evaluation assumptions did not take into account the downlink (DL) satellite power split among multiple DL satellite beams.

The power reduction due to beam splitting is closely related to the dedicated deployment. A satellite supporting more simultaneous active satellite beams can result in a larger serving area. However, it also leads to a more significant reduction in the transmission power over a single beam, naturally yielding a more reduced per-beam SNR (Signal-to-Noise Ratio) . Therefore, when the power split is considered, there is also a need for DL coverage enhancement. For instance, from TR38.821, the maximum beam footprint size (edge to edge) regardless of the elevation angle is 1000km for Low Earth Orbit (LEO) based NTN, and the satellite beam diameter is 50km for LEO-600 at S-band. Suppose D =50km × 3/2 ≈ 43.3km, N = 1000km/D ≈23, then, the required total beam numbers spreading over the max beam footprint with 1000km is at most 400. Thus, almost a 26dB power reduction relative to total power would occur for each beam if beam split is considered.

Obviously, the DL channel for NTN will be the coverage bottleneck channel and needs enhancement. Potential coverage bottleneck channels can be at least one of the following: SIB1 and corresponding scheduling DCI; Msg2 and corresponding scheduling PDCCH; Msg4 and corresponding scheduling PDCCH; MsgB; Paging; PDCCH; PDSCH and a system information block (e.g., SIB19 or SIB x) .

FIG. 1 shows a flowchart of a 4-step Random Access Channel (RACH) procedure. FIG. 2 illustrates time relationship between each channel during random access procedure. Firstly, the user equipment (UE) transmit a RACH preamble (MSG1) to the base station (gNB) , and then a Ra-ResponseWindow is started. Within the window, the UE needs to monitor a Random Access Response (RAR or MSG2) . After having detected the RAR correctly, the UE transmits the scheduled transmission (MSG3) based on the grant within the RAR. Then the UE needs to receive the contention resolution (MSG4) during a Ra-ContentionResoulution Timer. After having received the MSG4 correctly, the UE transmits a corresponding Hybrid Automatic Repeat Request Acknowledgement (HARQ-ACK) of MSG4.

The UE may also need to determine the starting point of MSG3. Specifically, after the UE sends a Physical Random Access Channel (PRACH) transmission, it tries to detect a Downlink Control Information (DCI) format 1_0 with Cyclic Redundancy Check (CRC) scrambled by a corresponding Random Access-Radio Network Temporary Identifier (RA-RNTI) within a detection window (Ra-ResponseWindow) . The detection window is controlled by higher layers (as introduced in [11, TS 38.321] ) . The window starts at the first symbol of the earliest Control Resource Set (CORESET) that the UE is configured to receive Physical Downlink Control Channel (PDCCH) for Type1-PDCCH CSS set, that is, the symbol after the last symbol of the PRACH occasion of the PRACH transmission. The symbol duration may correspond to the SCS for Type1-PDCCH CSS set. Ifor (as defined in [4, TS 38.211] ) is non-zero, the window starts after an additional T_TA+k_mac milisec, where T_TA is defined in [4, TS 38.211] and k_mac is provided by kmac or k_mac=0. If kmac is not provided. The length of the window in number of slots, based on the SCS for Type1-PDCCH CSS set, is provided by ra-ResponseWindow. Regarding slots for a Physical Uplink Shared Channel (PUSCH) transmission scheduled by a RAR Uplink grant, if a UE receives a Physical Downlink Shared Channel (PDSCH) with a RAR message ending in slot n, the UE transmits the PUSCH in slot n+k₂+Δ+2^μ·K_{cell, offset}, where k₂ and Δ are provided in [6, TS 38.214] and K_{cell, offset} is provided by cellSpecificKoffset. If K_{cell, offset} is not provided, then K_{cell, offset}=0.

According to some embodiments of the present disclosure, repetition of the RAR (MSG2) is enabled for improving coverage capacity. In this case, the reference point used to determine the starting point of MSG3 needs to be redefined. Similarly, according to some embodiments of the present disclosure, repetition of MSG4 is enabled, and the reference point used to determine the starting point of the HARQ-ACK of MSG4 needs to be redefined.

Moreover, Downlink (DL) coverage capacity can pose a significant challenge for Non-Terrestrial Networks (NTN) , especially when a User Equipment (UE) is in an area with poor coverage due to movement or environmental factors. Users may unknowingly find themselves in conditions of deep fading or non-line-of-sight (NLOS) situations. In such cases, when services like paging messages or calls are incoming, there's a risk of missing these communications, leading to a decrease in DL capacity. To address this issue, the most straightforward solution is to enhance the coverage of paging. However, this approach would require significant time/frequency resources and power consumption. Therefore, an alternative solution could be to introduce a gNB (next-generation Node B) controlled simple notification/alert system. This system would be designed to remain robust even in deep fading conditions. Considerations for this system could include its detailed design, periodicity, relationship with paging, the number of UEs it can indicate, and whether to use a sequence or group common DCI (Downlink Control Information) with a small size, among other factors.

The present disclosure provides multiple solutions to solve at least some of the above-mentioned issues.

Solution #1: Coverage Enhancement for SIB1

The present solution proposes a method/methods to improve the coverage capacity for System Information Block Type 1 (SIB1) . SIB1 transmission with repetitions, and SIB1 transmission across multiple CORESET/symbols/slots are introduced. Furthermore, a method to determine whether SIB1 transmission with repetitions or SIB1 transmission across multiple CORESET/symbols/slots is enabled is provided. The implementation of any of the above methods may improve the coverage capacity of SIB1.

The Downlink (DL) channel of SIB1 includes two parts. Part 1 is a System Information-Radio Network Temporary Identifier (SI-RNTI) scrambled Downlink Control Information (DCI) , also known as Physical Downlink Control Channel (PDCCH) . This is used to schedule the SIB1 Physical Downlink Shared Channel (PDSCH) . Part 2 is the SIB1 PDSCH, which is used to convey the remaining system information. In the current specification, a total of 8 bits within the Master Information Block (MIB) are used to indicate the Control Resource Set (CORESET) 0 and the corresponding search space (denoted as Search Space 0, SS-0) . The parameters of CORESET 0 and Search Space 0 are pre-defined in TS 38.213, which includes a set of pre-defined tables.

In one situation, control information of SIB1 is under coverage bottleneck. Accordingly, repetition and control information transmission with low code rate can be considered, detailed explanation of which is given below.

Method #1: Repetition of DCI which is used to schedule SIB1 can be enabled. The repetition number of the DCI can be indicated, for example, through joint coding with CORESET for Type0-PDCCH search space set. This can be achieved by adding a new column to the table of Set of resource blocks and slot symbols of CORESET for Type0-PDCCH search space set, as shown in Table 1. The original table is defined in [TS 38.213] . In this way, coverage capacity can be improved without increasing the signaling overhead.

Table 1: Joint Coding of Repetition number of DCI for SIB1 and set of resource blocks and slot symbols of CORESET for Type0-PDCCH search space set when {SS/PBCH block, PDCCH} SCS is {15, 15} kHz for frequency bands with minimum channel bandwidth 5 MHz or 10 MHz

It should be noticed, the above table of Set of resource blocks and slot symbols of CORESET for Type0-PDCCH search space set is merely for illustrative purpose, and other tables of CORESET for SS 0 defined in [TS 38.213] can also be adopted.

In some embodiments, the DCI repetition is based on the repetition number of DCI and/or and within athe DCI is only repeated once (or up to once) . For instance, when CORESET for Type0-PDCCH is indicated as “index 0” , the corresponding Number of Symbols for CORESET 0 is 2 and Repetition Number of DCI is 4. Accordingly, as shown in FIG. 3, a scheduling DCI for SIB1 can be repeated over 4 contiguous or non-contiguousIn FIG. 3, symbols of CORESET 0-1 means the symbols for the firstsymbols of CORESET 0-2 means the symbols for the secondsymbols of CORESET 0-3 means the symbols for the thirdsymbols of CORESET 0-2 means the symbols for the fourth

Method #2: Transmission of control information of SIB1 across multiple symbols may be enabled, that is, transmission of a DCI for scheduling SIB1 may occupy multiple (more than 2) symbols. The number of symbols that the DCI transmission occupies can be indicated, for example, through joint coding with CORESET for Type0-PDCCH search space set. This can be achieved by adding a new column (DAS, DCI across symbols) to the table of Set of resource blocks and slot symbols of CORESET for Type0-PDCCH search space set, as shown in Table 2. The original table is defined in [TS 38.213] . The number of symbols that the DCI transmission occupies can be multiples ofSince the DCI transmission can cross more than 2 symbols, low code rate of DCI can be adopted, which may improve the coverage capacity of the DCI. The number of symbols that the DCI transmission occupies can be determined based on the DAS and/orFor example, when CORESET for Type0-PDCCH is indicated as “index 0” , it can be acquired based on table 2 that the number of symbols for CORESET 0 is 2 and the DAS number is equal to 2*2=4. As shown in FIG. 4, a scheduling DCI for SIB1 may cross 2 contiguous or non-contiguousIn FIG. 4, symbols of CORESET 0-1 means the symbols for the firstsymbols of CORESET 0-2 means the symbols for the second

Table 2: Joint Coding of DAS number and set of resource blocks and slot symbols of CORESET for Type0-PDCCH search space set when {SS/PBCH block, PDCCH} SCS is {15, 15} kHz for frequency bands with minimum channel bandwidth 5 MHz or 10 MHz

Method #3: A new parameter within Master Information Block (MIB) can be used to indicate the repetition number of DCI for scheduling SIB1. Alternatively or additionally, a new parameter within MIB can be used to indicate the multiple symbols that the DCI transmission occupies. In this way, the repetition number of DCI or the number of symbols that the DCI transmission occupies can be flexibly indicated and the coverage capacity of the scheduling DCI of SIB1 can be improved.

In some cases, both repetition and cross-symbol transmission are enabled for the scheduling DCI of SIB1. Due to limited information, an ambiguity between the base station and the UE may be caused. For example, when a UE receives a Synchronization Signal Block (SSB) and MIB, it cannot know which indication is to be used. Here the indication includes indication for repetition of the scheduling DCI and indication for cross-symbol transmission of the scheduling DCI. There can exist two cases. In case 1, when both values of repetition number and DAS are indicated by the same parameter of a same table, ambiguity may occur between the base station and the UE. In case 2, when values of repetition number and DAS are indicated by different tables, the UE still cannot know which table should be used and thus ambiguity may occur between the base station and the UE.

To solve the problem, a straightforward way is to introduce a new SI-RNTI. The new SI-RNTI can be one of {FFF3–FFFB} . Legacy SI-RNTI (e.g., FFFF) can be used to indicate repetition of DCI, while the new introduced SI-RNTI (one of FFF3-FFFB) can be used to indicate the cross-symbol transmission of the scheduling DCI of SIB1. Alternatively, the new introduced SI-RNTI (one of FFF3-FFFB) can be used to indicate repetition of the scheduling DCI of SIB1, while the legacy SI-RNTI (FFFF) can be used to indicate the cross-symbol transmission of the scheduling DCI of SIB1.

In one situation, SIB 1 PDSCH is under coverage bottleneck. Accordingly, at least one of the following methods can be considered: repetition of SIB1 PDSCH, cross-slot/symbol transmission of SIB1 PDSCH, and joint channel estimation (can also be denoted as DMRS-bundling) between multiple slots/symbols that are used to transmit a same Transmission Block (TB) . Detailed explanation of these methods is given below.

Method #4: Repetition of SIB1 PDSCH can be enabled. The repetition number of the SIB 1 PDSCH can be indicated via a field of the scheduling DCI, e.g., the reserved field within DCI format 1_0 scrambled by SI-RNTI. The size of the filed can be equal to, for example, ceil of log₂ (candidate repetition number of SIB1 PDSCH) or log₂ (maximum number of SIB1 PDSCH) . The candidate repetition number and/or the maximum number of SIB1 PDSCH can be pre-defined.

Method #5: Repetition of SIB1 PDSCH can be enabled. The repetition number of the SIB 1 PDSCH can be indicated via a field of the scheduling DCI, e.g., Time Domain Resource Allocation (TDRA) . Specifically, a new column is introduced to a TDRA table and the new column is used to indicate the repetition number of SIB1 PDSCH, as shown in table 3. In table 3, joint coding of the repetition number of SIB1 PDSCH and default PDSCH time domain resource allocation A for normal CP is shown.

Table 3: Joint Coding of Repetition Number of SIB1 PDSCH and Default PDSCH Time Domain Resource Allocation A for Normal CP

It should be noticed, the above table of Default PDSCH time domain resource allocation A for normal CP is merely for illustrative purpose, and other tables defined in [TS 38.214] can also be adopted to indicate the repetition number of SIB1 PDSCH, e.g., Default PDSCH time domain resource allocation A for extended CP, Default PDSCH time domain resource allocation B, Default PDSCH time domain resource allocation C, etc.

In some embodiments, when repetition of SIB1 PDSCH is enabled, joint channel estimation can be enabled. That is, a set of Demodulation Reference Signal (DMRS) or all of the DMRS within the time duration for repetition transmission of SIB1 PDSCH can be bundled, and the UE can use the bundled DMRS to perform channel estimation. 1 bit or 2bits information within the scheduling DCI of SIB1 PDSCH can be used for indication. For instance, when 1 bit information within the scheduling DCI of SIB1 PDSCH is used to indicate the joint channel estimation, state of “1” can mean that the SIB1 PDSCH with repetition can be used for joint channel estimation while state of “0” can mean that the SIB1 PDSCH with repetition cannot be used for joint channel estimation. Alternatively, state of “0” can mean that the SIB1 PDSCH with repetition can be used for joint channel estimation while state of “1” can mean that the SIB1 PDSCH with repetition cannot be used for joint channel estimation. When 2 bits information within the scheduling DCI of SIB1 PDSCH is used to indicate the joint channel estimation, the states can be defined, for example, in table 4 as shown below.

Table 4: Joint Channel Estimation Indication

Method #6: Cross-slot transmission of SIB1 PDSCH can be enabled. The number of slots that the SIB1 PDSCH transmission occupies can be indicated via a field of the scheduling DCI, e.g., the reserved field within DCI format 1_0 scrambled by SI-RNTI. The size of the filed can be equal to, for example, ceil of log₂ (candidate slot number for SIB1 PDSCH transmission) or log₂ (maximum number of slots for SIB1 PDSCH transmission) . The candidate slot number for SIB1 PDSCH transmission and/or the maximum number of slots for SIB1 PDSCH transmission can be pre-defined.

Method #7: Cross-slot transmission of SIB1 PDSCH can be enabled. The number of slots that the SIB1 PDSCH transmission occupies can be indicated via a field of the scheduling DCI, e.g., Time Domain Resource Allocation (TDRA) . Specifically, a new column is introduced to a TDRA table and the new column is used to indicate the number of slots that the SIB1 PDSCH transmission occupies, as shown in table 5. In table 5, joint coding of the slot number of SIB1 PDSCH transmission and default PDSCH time domain resource allocation A for normal CP is shown.

Table 5: Joint Coding of Slot Number of SIB1 PDSCH Transmission and Default PDSCH Time Domain Resource Allocation A for Normal CP

It should be noticed, the above table of Default PDSCH time domain resource allocation A for normal CP is merely for illustrative purpose, and other tables defined in [TS 38.214] can also be adopted to indicate the slot number of SIB1 PDSCH transmission, e.g., Default PDSCH time domain resource allocation A for extended CP, Default PDSCH time domain resource allocation B, Default PDSCH time domain resource allocation C, etc.

Solution #2: Coverage Enhancement for MSG2

The present solution proposes a method/methods to improve the coverage capacity for MSG2 of a random access procedure (as shown in FIGS. 1 and 2) . MSG2 transmission with repetitions, and MSG2 transmission across multiple CORESET/symbols/slots are introduced. Furthermore, a method to determine whether MSG2 transmission with repetitions or MSG2 transmission across multiple CORESET/symbols/slots is enabled is provided. The implementation of any of the above methods may improve the coverage capacity of MSG2.

The Downlink (DL) channel of MSG2 includes two parts. Part 1 is a System Information-Radio Network Temporary Identifier (SI-RNTI) scrambled Downlink Control Information (DCI) , also known as Physical Downlink Control Channel (PDCCH) . This is used to schedule the MSG2 Physical Downlink Shared Channel (PDSCH) . Part 2 is the MSG2 PDSCH, which is used to respond to the RACH preamble.

In one situation, control information of MSG2 is under coverage bottleneck. Accordingly, repetition and control information transmission with low code rate can be considered, detailed explanation of which is given below.

In one embodiment, repetition of the MSG2 PDCCH is enabled. The repetition number of the MSG2 PDCCH can be indicated by SIB1. Alternatively or additionally, the repetition number of the MSG2 PDCCH can be determined based on the number of the PRACH (MSG1) transmissions, that is, the repetition number of the MSG2 PDCCH may be equal to the repetition number of MSG1 or equal to the repetition number of MSG1 plus a delta value.

In one embodiment, the MSG2 PDCCH can be transmitted across multiple symbols, which means transmission of a DCI for scheduling MSG2 can occupy multiple symbols (more than 2) . The number of symbols that the DCI transmission occupies can be indicated by SIB1.

In one situation, MSG2 PDSCH is under coverage bottleneck. Accordingly, at least one of the following methods can be considered: repetition of MSG2 PDSCH, cross-slot/symbol transmission of MSG2 PDSCH, and joint channel estimation (can also be denoted as DMRS-bundling) between multiple slots/symbols that are used to transmit a same Transmission Block (TB) . Detailed explanation of these methods is given below.

Method #1: Repetition of MSG2 PDSCH can be enabled. The repetition number of the MSG2 PDSCH can be indicated via a field of the scheduling DCI, e.g., the reserved field within DCI format 1_0 scrambled by SI-RNTI. The size of the filed can be equal to, for example, ceil of log₂ (candidate repetition number of MSG2 PDSCH) or log₂ (maximum number of MSG2 PDSCH) . The candidate repetition number and/or the maximum number of MSG2 PDSCH can be pre-defined.

Method #2: Repetition of MSG2 PDSCH can be enabled. The repetition number of the MSG2 PDSCH can be indicated via a field of the scheduling DCI, e.g., Time Domain Resource Allocation (TDRA) . Specifically, a new column is introduced to a TDRA table and the new column is used to indicate the repetition number of MSG2 PDSCH, as shown in table 6. In table 6, joint coding of the repetition number of MSG2 PDSCH and default PDSCH time domain resource allocation A for normal CP is shown.

Table 6: Joint Coding of Repetition Number of MSG2 PDSCH and Default PDSCH Time Domain Resource Allocation A for Normal CP

It should be noticed, the above table of Default PDSCH time domain resource allocation A for normal CP is merely for illustrative purpose, and other tables defined in [TS 38.214] can also be adopted to indicate the repetition number of MSG2 PDSCH, e.g., Default PDSCH time domain resource allocation A for extended CP, Default PDSCH time domain resource allocation B, Default PDSCH time domain resource allocation C, etc.

In some embodiments, when repetition of MSG2 PDSCH is enabled, joint channel estimation can be enabled. That is, a set of Demodulation Reference Signal (DMRS) or all of the DMRS within the time duration for repetition transmission of MSG2 PDSCH can be bundled, and the UE can use the bundled DMRS to perform channel estimation. A field within the scheduling DCI of MSG2 PDSCH can be used for indication. For instance, state of “1” of the field can mean that the MSG2 PDSCH with repetition can be used for joint channel estimation while state of “0” can mean that the MSG2 PDSCH with repetition cannot be used for joint channel estimation. Alternatively, state of “0” can mean that the MSG2 PDSCH with repetition can be used for joint channel estimation while state of “1” can mean that the MSG2 PDSCH with repetition cannot be used for joint channel estimation.

Method #3: Cross-slot transmission of MSG2 PDSCH can be enabled. The number of slots that the MSG2 PDSCH transmission occupies can be indicated via a field of the scheduling DCI, e.g., the reserved field within DCI format 1_0 scrambled by SI-RNTI. The size of the filed can be equal to, for example, ceil of log₂ (candidate slot number for MSG2 PDSCH transmission) or log₂ (maximum number of slots for MSG2 PDSCH transmission) . The candidate slot number for MSG2 PDSCH transmission and/or the maximum number of slots for MSG2 PDSCH transmission can be pre-defined.

Method #4: Cross-slot transmission of MSG2 PDSCH can be enabled. The number of slots that the MSG2 PDSCH transmission occupies can be indicated via a field of the scheduling DCI, e.g., Time Domain Resource Allocation (TDRA) . Specifically, a new column can be introduced to a TDRA table and the new column is used to indicate the number of slots that the MSG2 PDSCH transmission occupies. For example, tables defined in [TS 38.214] can be adopted to indicate the slot number of MSG2 PDSCH transmission, e.g., Default PDSCH time domain resource allocation A for normal CP, Default PDSCH time domain resource allocation A for extended CP, Default PDSCH time domain resource allocation B, Default PDSCH time domain resource allocation C, etc.

Method #5: The repetition number of MSG2/MSG2 PDSCH can be determined based on the number of multiple PRACH transmissions, that is, the repetition number of MSG2/MSG2 PDSCH can be equal to the number of multiple PRACH transmissions or equal to the number of multiple PRACH transmissions plus a delta value. Alternatively, the number of slots that MSG2/MSG2 PDSCH transmission occupies can be determined based on the number of multiple PRACH transmissions, that is, the slot number of MSG2/MSG2 PDSCH transmission can be equal to the number of multiple PRACH transmissions or equal to the number of multiple PRACH transmissions plus a delta value.

Method #6: The repetition number of MSG2/MSG2 PDSCH can be determined based on a Control Channel Element (CCE) aggregation level of DCI scrambled by RA-RNTI. Each CCE aggregation level of the DCI can be used to indicate one value of repetition number of MSG2/MSG2 PDSCH. Alternatively, the number of slots that MSG2/MSG2 PDSCH transmission occupies can be determined based on a Control Channel Element (CCE) aggregation level of DCI scrambled by RA-RNTI. Each CCE aggregation level of the DCI can be used to indicate one value of the slot number of MSG2/MSG2 PDSCH transmission. The higher the aggregation level, the poorer the channel condition. Thus, a higher CCE aggregation level may indicate a larger repetition number or a larger slot amount of MSG2/MSG2 PDSCH transmission.

Method #7: A new SI-RNTI can be introduced. The new SI-RNTI can be one of {FFF3–FFFB} . Legacy SI-RNTI (e.g., FFFF) can be used to indicate repetition of MSG2 PDCCH/PDSCH, while the new introduced SI-RNTI (one of FFF3-FFFB) can be used to indicate the cross-symbol transmission of MSG2 PDCCH/PDSCH. Alternatively, the new introduced SI-RNTI (one of FFF3-FFFB) can be used to indicate repetition of MSG2 PDCCH/PDSCH, while the legacy SI-RNTI (FFFF) can be used to indicate the cross-symbol transmission of MSG2 PDCCH/PDSCH.

Solution #3: Coverage Enhancement for MSG4

The present solution proposes a method/methods to improve the coverage capacity for MSG4 of a random access procedure (as shown in FIGS. 1 and 2) . MSG4 transmission with repetitions, and MSG4 transmission across multiple CORESET/symbols/slots are introduced. Furthermore, a method to determine whether MSG4 transmission with repetitions or MSG4 transmission across multiple CORESET/symbols/slots is enabled is provided. The implementation of any of the above methods may improve the coverage capacity of MSG4.

The Downlink (DL) channel of MSG4 includes two parts. Part 1 is a System Information-Radio Network Temporary Identifier (SI-RNTI) scrambled Downlink Control Information (DCI) , also known as Physical Downlink Control Channel (PDCCH) . This is used to schedule the MSG4 Physical Downlink Shared Channel (PDSCH) . Part 2 is the MSG4 PDSCH.

In one situation, control information of MSG4 is under coverage bottleneck. Accordingly, repetition and control information transmission with low code rate can be considered, detailed explanation of which is given below.

In one embodiment, repetition of the MSG4 PDCCH is enabled. The repetition number of the MSG4 PDCCH can be indicated by MSG3 or MSG1. Alternatively or additionally, the repetition number of the MSG4 PDCCH can be determined based on the number of the MSG3 transmissions, that is, the repetition number of the MSG4 PDCCH may be equal to the repetition number of MSG3 or equal to the repetition number of MSG3 plus a delta value.

In one embodiment, the MSG4 PDCCH can be transmitted across multiple symbols, which means transmission of a DCI for scheduling MSG4 can occupy multiple symbols (more than 2) . The number of symbols that the DCI transmission occupies can be indicated by SIB1 or MSG3.

In one situation, MSG4 PDSCH is under coverage bottleneck. Accordingly, at least one of the following methods can be considered: repetition of MSG4 PDSCH, cross-slot/symbol transmission of MSG4 PDSCH, and joint channel estimation (can also be denoted as DMRS-bundling) between multiple slots/symbols that are used to transmit a same Transmission Block (TB) . These method are similar to those related to MSG2 PDSCH, detailed explanation will not be repeated herein for simplicity and clarity.

In some embodiments, the repetition number of MSG4/MSG4 PDSCH can be determined based on the number of MSG3 repetitions, that is, the repetition number of MSG4/MSG4 PDSCH can be equal to the number of MSG3 repetitions or equal to the number of MSG3 repetitions plus a delta value. Alternatively, the number of slots that MSG4/MSG4 PDSCH transmission occupies can be determined based on the number of MSG3 repetitions, that is, the slot number of MSG4/MSG4 PDSCH transmission can be equal to the number of MSG3 repetitions or equal to the number of MSG3 repetitions plus a delta value.

In some embodiments, the repetition number of MSG4/MSG4 PDSCH can be determined based on a Control Channel Element (CCE) aggregation level of DCI scrambled by RA-RNTI. Each CCE aggregation level of the DCI can be used to indicate one value of repetition number of MSG4/MSG4 PDSCH. Alternatively, the number of slots that MSG4/MSG4 PDSCH transmission occupies can be determined based on a Control Channel Element (CCE) aggregation level of DCI scrambled by RA-RNTI. Each CCE aggregation level of the DCI can be used to indicate one value of the slot number of MSG4/MSG4 PDSCH transmission. The higher the aggregation level, the poorer the channel condition. Thus, a higher CCE aggregation level may indicate a larger repetition number or a larger slot amount of MSG4/MSG4 PDSCH transmission.

It should be understood, the methods described in solutions #1 to #3 can also be adopted for other DL channels such as MsgB, paging messages and SIB x (e.g., SIB 19 or other SIB information) . Solution #4: Determination of Time Relationship between MSG2 and MSG3

The present solution proposes a method or methods to determine the time relationship between MSG2 and subsequent MSG3 when repetition of MSG2 is enabled. The first repetition of Msg2, the last repetition of Msg2, or more than one repetition of Msg2 can be defined as a reference point. These reference points are used to determine the time relationship, thereby avoiding ambiguity between the user device and the base station. Additionally, this method can reduce the detection time for Msg3 at the base station. In the current specification, a set timeline for Random Access Channel (RACH) access is defined. When a User Equipment (UE) transmits a RACH preamble to the gNB (next-generation Node B) , a Random Access Response Window (RAR window) begins. During the RAR window, the UE needs to monitor a Random Access Response (RAR) . After the UE correctly detects the RAR, it transmits Msg3 based on the grant of the RAR. Following the transmission of Msg3, the UE needs to receive Msg4 during a Ra-ContentionResolutionTimer. Once the UE correctly receives Msg4, a corresponding Hybrid Automatic Repeat Request Acknowledgement (HARQ-ACK) of Msg4 is required. However, when Msg2 with repetition is enabled during the random access procedure, the current mechanism to determine the starting point of Msg3 is no longer suitable. Therefore, enhancements are needed, and the following methods can be considered.

Method #1: The first repetition of MSG2/MSG2 PDSCH can be defined as a reference point used to determine the starting point of MSG3. Referring to a slot or a set of slots for a Physical Uplink Shared Channel (PUSCH) transmission (also denoted as Msg3) which is scheduled via a MSG2 message, and assuming the first repetition of MSG2 is located on slot n, it can be determined that the UE transmits the MSG3 PUSCH in slot n+k₂+Δ+2^μ·K_{cell, offset}. In the equation, k₂ and Δ are provided in [6, TS 38.214] and K_{cell, offset} is provided by cellSpecificKoffset. If not provided, K_{cell, offset}=0. FIG. 5 illustrates an example where a first repetition of MSG2 is utilized for determining time relationship between MSG2 and MSG3 according to an embodiment of the present disclosure. In FIG. 5, MSG2 has 4 repetitions and the first one is taken as the reference point to determine the starting point of MSG3.

Method #2: Multiple repetitions of MSG2 can be defined as reference points used to determine the starting point of MSG3. Referring to a slot or a set of slots for a Physical Uplink Shared Channel (PUSCH) transmission (also denoted as Msg3) which is scheduled via a MSG2 message, and assuming the repetitions of MSG2 is located on slot [n, n+1…n+i-1] respectively, it can be determined that the UE transmits the MSG3 PUSCH in slot n+k₂+Δ+2^μ·K_{cell, offset}, n+1+k₂+Δ+2^μ·K_{cell, offset}, and/or n+i-1+k₂+Δ+2^μ·K_{cell, offset}. In the equation, k₂ and Δ are provided in [6, TS 38.214] , i is the i-th repetition of MSG2 and K_{cell, offset} is provided by cellSpecificKoffset. If not provided, K_{cell, offset}=0.

Method #3: Repetitions of MSG2 can be split into multiple groups, and the first or the last repetition (or the first/last available repetition) of MSG2 within a group can be defined as a reference point used to determine the starting point of MSG3. Referring to a slot or a set of slots for a Physical Uplink Shared Channel (PUSCH) transmission (also denoted as Msg3) which is scheduled via a MSG2 message, and assuming the first/last repetition of MSG2 within a group i is located on slot n+timeoffsetAi (i=0, 1, …) , it can be determined that the UE transmits the MSG3 PUSCH in slot n+timeoffsetAi-1+k₂+Δ+2^μ·K_{cell, offset}. In the equation, k₂ and Δ are provided in [6, TS 38.214] , and K_{cell, offset} is provided by cellSpecificKoffset. If not provided, K_{cell, offset}=0. TimeoffsetAi is the location of the first/last repetition of MSG2 within a group i with regard to the slot n (location of the first repetition of MSG2) . FIG. 6 illustrates an example where multiple sub-sets of repetitions of MSG2 are utilized for determining time relationship between MSG2 and MSG3 according to an embodiment of the present disclosure. In FIG. 6, MSG2 has 4 repetitions that are divided into two groups. The last repetition of MSG2 within each group is taken as the reference point to determine the starting point of MSG3.

Method #4: The last repetition or last available repetition of MSG2/MSG2 PDSCH can be defined as a reference point used to determine the starting point of MSG3. Referring to a slot or a set of slots for a Physical Uplink Shared Channel (PUSCH) transmission (also denoted as Msg3) which is scheduled via a MSG2 message, and assuming the last repetition of MSG2 is located on slot n, it can be determined that the UE transmits the MSG3 PUSCH in slot n+k₂+Δ+2^μ·K_{cell, offset} . In the equation, k₂ and Δ are provided in [6, TS 38.214] and K_{cell, offset} is provided by cellSpecificKoffset. If not provided, K_{cell, offset}=0. FIG. 7 illustrates an example where a last repetition of MSG2 is utilized for determining time relationship between MSG2 and MSG3 according to an embodiment of the present disclosure. In FIG. 7, MSG2 has 4 repetitions and the last one is taken as the reference point to determine the starting point of MSG3.

Method #5: A given repetition of MSG2/MSG2 PDSCH can be defined as a reference point used to determine the starting point of MSG3. Referring to a slot or a set of slots for a Physical Uplink Shared Channel (PUSCH) transmission (also denoted as Msg3) which is scheduled via a MSG2 message, and assuming a given repetition of MSG2 is located on slot n, it can be determined that the UE transmits the MSG3 PUSCH in slot n+k₂+Δ+2^μ·K_{cell, offset}. In the equation, k₂ and Δ are provided in [6, TS 38.214] and K_{cell, offset} is provided by cellSpecificKoffset. If not provided, K_{cell, offset}=0. In this case, which repetition of MSG2 is used to determine the starting point of MSG3 can be pre-defined and indicated via a DCI scrambled by RA-RNTI.

Solution #5: Determination of Time Relationship between MSG4 and HARQ-ACK of MSG4

The present solution proposes a method or methods to determine the time relationship between MSG4 and subsequent HARQ-ACK feedback of MSG4 when repetition of MSG4 is enabled. The first repetition of Msg4, the last repetition of Msg4, or more than one repetition of Msg4 can be defined as a reference point. These reference points are used to determine the time relationship, thereby avoiding ambiguity between the user device and the base station. Additionally, this method can reduce the detection time for HARQ-ACK feedback of MSG4 at the base station. In the current specification, a set timeline for Random Access Channel (RACH) access is defined. When a User Equipment (UE) transmits a RACH preamble to the gNB (next-generation Node B) , a Random Access Response Window (RAR window) begins. During the RAR window, the UE needs to monitor a Random Access Response (RAR) . After the UE correctly detects the RAR, it transmits Msg3 based on the grant of the RAR. Following the transmission of Msg3, the UE needs to receive Msg4 during a Ra-ContentionResolutionTimer. Once the UE correctly receives Msg4, a corresponding Hybrid Automatic Repeat Request Acknowledgement (HARQ-ACK) of Msg4 is required. However, when Msg4 with repetition is enabled during the random access procedure, the current mechanism to determine the starting point of HARQ-ACK feedback of MSG4 is no longer suitable. Therefore, enhancements are needed, and the following methods can be considered.

Method #1: The first repetition of MSG4 PDSCH can be defined as a reference point used to determine the starting point of HARQ-ACK feedback of MSG4. A minimum time between the last symbol of the first MSG4 PDSCH repetition and the first symbol of the corresponding PUCCH transmission of the HARQ-ACK information may be equal to N_T, 1+0.5 ms. N_T, 1 is a time duration of N₁ symbols corresponding to a PDSCH processing time for UE processing capability 1 when additional PDSCH DM-RS is configured. For μ=0 , the UE assumes N_1, 0=14 [defined in TS 38.214] . With this way, latency for HARQ-ACK of Msg4 can be reduced.

Method #2: The last repetition of MSG4 PDSCH can be defined as a reference point used to determine the starting point of HARQ-ACK feedback of MSG4. A minimum time between the last symbol of the last MSG4 PDSCH repetition and the first symbol of the corresponding PUCCH transmission of the HARQ-ACK information may be equal to N_T, 1+0.5 ms. NM_, 1 is a time duration of N₁ symbols corresponding to a PDSCH processing time for UE processing capability 1 when additional PDSCH DM-RS is configured. For μ=0 , the UE assumes N_1, 0=14 [defined in TS 38.214] . With this way, latency for HARQ-ACK of Msg4 can be reduced.

Method #3: A given repetition of MSG4 PDSCH can be defined as a reference point used to determine the starting point of HARQ-ACK feedback of MSG4. A minimum time between the last symbol of the given MSG4 PDSCH repetition and the first symbol of the corresponding PUCCH transmission of the HARQ-ACK information may be equal to N_T, 1+0.5 ms. N_T, 1 is a time duration of N₁ symbols corresponding to a PDSCH processing time for UE processing capability 1 when additional PDSCH DM-RS is configured. For μ=0 , the UE assumes N_1, 0=14 [defined in TS 38.214] . In this case, which repetition of MSG4 is used to determine the starting point of HARQ-ACK feedback of MSG4 can be pre-defined and indicated via MSG4.

Method #4: Multiple repetitions of MSG4 PDSCH can be defined as reference points used to determine the starting point of HARQ-ACK feedback of MSG4. A minimum time between the last symbol of each of the multiple MSG4 PDSCH repetitions and the first symbol of the corresponding PUCCH transmission of the HARQ-ACK information may be equal to N_T, 1+0.5 ms. N_T, 1 is a time duration of N₁ symbols corresponding to a PDSCH processing time for UE processing capability 1 when additional PDSCH DM-RS is configured. For μ=0, the UE assumes N_1, 0=14 [defined in TS 38.214] . In this way, multiple PUCCH occasions can be provided to the UE, and correspondingly the latency for HARQ-ACK of MSG4 can be reduced.

Solution #6: Notification/Alert Signaling

As mentioned above, downlink (DL) coverage capacity is a significant issue for Non-Terrestrial Networks (NTN) , especially when a User Equipment (UE) experiences poor coverage due to movement or environmental factors. Users may unknowingly find themselves in poor reception conditions, experiencing deep fading and non-line-of-sight (NLOS) situations. In such cases, when services like paging messages or other messages arrive, there may be a risk of missing these messages, leading to decreased capacity. To address this issue, the most straightforward solution is to enhance the coverage of paging. However, this would require significant time/frequency resources or power consumption. Therefore, introducing a gNB-controlled simple notification/alert that can remain robust even in deep fading situations can be considered.

The present disclosure proposes methods to notify the UE whether it has missed any paging or not. With this approach, a notification can be received by the UE, informing it about the paging condition. Detailed designs are proposed, including periodicity, relationship with paging, the number of UEs that can be indicated, sequence or group common Downlink Control Information (DCI) with small size, etc.

DCI format 2_x can be used for notifying the paging missing indication for one or more UEs. The following information is transmitted by means of the DCI format 2_x with Cyclic Redundancy Check (CRC) scrambled by Paging Message Indicator-Radio Network Temporary Identifier (PMI-RNTI) , where PMI-RNTI is used to scramble DCI format 2_x for notifying the missed paging. At least one of the following parameters can be included: number of paging frames; number of paging occasions configured by higher layer parameters; number of UEs.

In some embodiments, the notification/alert is sent to the UE after paging. Then, the missed paging information located before the notification/alert can be indicated.

FIG. 8 is a flowchart of an enhancement method for a downlink (DL) channel in random access procedure according to an embodiment of the present disclosure. The method may be executed by a base station (e.g., gNB) . The method includes operations described in Blocks S101 to S102. In S101, an information of the DL channel is transmitted. In S102, at least one repetition of the information of the DL channel is transmitted.

According to the present embodiment, the enhancement method includes: transmitting an information of the DL channel; and transmitting at least one repetition of the information of the DL channel. Thus, the implementation of the method may enable repetition of the DL channel, and thus coverage capacity of the DL channel can be improved.

In one embodiment, the information of the DL channel includes scheduling Downlink Control Information (DCI) of System Information Block Type 1 (SIB1) . Repetition number configuration of the scheduling DCI of SIB1 may be included in configuration of Control Resource Set (CORESET) , and the method may further include: transmitting an index of the configuration of CORESET, and determining a repetition number of the at least one repetition based on the index of the configuration of CORESET.

In one embodiment, the information of the DL channel includes System Information Block Type 1 (SIB1) Physical Downlink Shared Channel (PDSCH) .

In some embodiments, repetition number configuration of the SIB1 PDSCH may be included in corresponding Downlink Control Information (DCI) of the SIB1 PDSCH. Specifically, the repetition number configuration of the SIB1 PDSCH is included in configuration of time domain resource allocation (TDRA) of the SIB1 PDSCH, and the method further includes: transmitting an index of the configuration of TDRA of the SIB1 PDSCH; and determining a repetition number of the at least one repetition based on the index of the configuration of TDRA of the SIB1 PDSCH. Alternatively, the repetition number configuration of the SIB1 PDSCH is indicated in a field of the corresponding DCI.

In some embodiments, the method may further include: transmitting an indicator for indicating whether Demodulation Reference Signals (DMRS) of the at least one repetition of the SIB1 PDSCH are enabled for joint channel estimation.

In one embodiment, the information of the DL channel includes scheduling Physical Downlink Control Channel (PDCCH) of MSG2. Repetition number configuration is included in System Information Block Type 1 (SIB1) . Specifically, a repetition number of the scheduling PDCCH of MSG2 is determined based on a repetition number of MSG1.

In one embodiment, the information of the DL channel includes Physical Downlink Shared Channel (PDSCH) of MSG2.

In some embodiments, repetition number configuration is included in corresponding Downlink Control Information (DCI) of the PDSCH of MSG2. For example, the repetition number configuration is included in configuration of time domain resource allocation (TDRA) of the PDSCH of MSG2, and the method further includes: transmitting an index of the configuration of TDRA of the PDSCH of MSG2; and determining a repetition number of the at least one repetition based on the index of the configuration of TDRA of the PDSCH of MSG2. Alternatively, the repetition number configuration is indicated in a field of the corresponding DCI.

In some embodiments, a repetition number of the PDSCH of MSG2 is determined based on a repetition number of MSG1.

In some embodiments, a repetition number of the PDSCH of MSG2 is determined based on a Control Channel Element (CCE) aggregation level.

In some embodiments, the method may further include: transmitting an indicator for indicating whether Demodulation Reference Signals (DMRS) of the at least one repetition of the PDSCH of MSG2 are enabled for joint channel estimation.

In some embodiments, the method may further include: determining a time relationship between MSG3 to be received and the at least one repetition of the PDSCH of MSG2; and receiving the MSG3 based on the determined time relationship. Specifically, the operation of determining the time relationship between MSG3 to be received and the at least one repetition of the PDSCH of MSG2 may include one of: using a first repetition of the at least one repetition of the PDSCH of MSG2 as reference to determine the time relationship; or using any one of the at least one repetition of the PDSCH of MSG2 as reference to determine the time relationship; or dividing the at least one repetition of the PDSCH of MSG2 into multiple sub-sets, and using a first or last repetition of the PDSCH of MSG2 of each of the sub-sets as reference to determine the time relationship; or using a last repetition of the at least one repetition of the PDSCH of MSG2 as reference to determine the time relationship.

In one embodiment, the information of the DL channel includes: scheduling Physical Downlink Control Channel (PDCCH) of MSG4. Repetition number configuration is included in MSG1 or MSG3. Alternatively, a repetition number of the scheduling PDCCH of MSG4 is determined based on a repetition number of MSG3.

In one embodiment, the information of the DL channel includes: Physical Downlink Shared Channel (PDSCH) of MSG4.

In some embodiments, repetition number configuration is included in corresponding Downlink Control Information (DCI) of the PDSCH of MSG4. Specifically, the repetition number configuration is included in configuration of time domain resource allocation (TDRA) of the PDSCH of MSG4, and the method may further include: transmitting an index of the configuration of TDRA of the PDSCH of MSG4; and determining a repetition number of the at least one repetition based on the index of the configuration of TDRA of the PDSCH of MSG4. Alternatively, the repetition number configuration is indicated in a field of the corresponding DCI.

In some embodiments, a repetition number of the PDSCH of MSG4 is determined based on a repetition number of MSG3. Alternatively, a repetition number of the PDSCH of MSG4 is determined based on a Control Channel Element (CCE) aggregation level.

In some embodiments, the method may further include: determining a time relationship between HARQ-ACK feedback of MSG4 to be received and the at least one repetition of the PDSCH of MSG4; and receiving the HARQ-ACK feedback of MSG4 based on the determined time relationship. Specifically, the operation of determining the time relationship between HARQ-ACK feedback of MSG4 to be received and the at least one repetition of the PDSCH of MSG4 includes at least one of: using a first repetition of the at least one repetition of the PDSCH of MSG4 as reference to determine the time relationship; or using any one of the at least one repetition of the PDSCH of MSG4 as reference to determine the time relationship; or using a last repetition of the at least one repetition of the PDSCH of MSG4 as reference to determine the time relationship.

FIG. 9 is a flowchart of an enhancement method for a downlink (DL) channel in random access procedure according to another embodiment of the present disclosure. The method may be executed by a user equipment (UE) or user device. The method includes operations described in Blocks S201 to S202. In S201, an information of the DL channel is received. In S202, at least one repetition of the information of the DL channel is received.

According to the present embodiment, the enhancement method includes: receiving an information of the DL channel; and receiving at least one repetition of the information of the DL channel. Thus, the implementation of the method may enable repetition of the DL channel, and thus coverage capacity of the DL channel can be improved.

In one embodiment, the information of the DL channel comprises scheduling Downlink Control Information (DCI) of System Information Block Type 1 (SIB1) . Repetition number configuration is included in configuration of Control Resource Set (CORESET) , and the method further comprises: receiving an index of the configuration of CORESET, and determining a repetition number of the at least one repetition based on the index of the configuration of CORESET.

In one embodiment, the information of the DL channel comprises System Information Block Type 1 (SIB1) Physical Downlink Shared Channel (PDSCH) . Repetition number configuration is included in corresponding Downlink Control Information (DCI) of the SIB1 PDSCH.

The method may further include: receiving an indicator for indicating whether Demodulation Reference Signals (DMRS) of the at least one repetition of the SIB1 PDSCH are enabled for joint channel estimation.

In one embodiment, the information of the DL channel comprises scheduling Physical Downlink Control Channel (PDCCH) of MSG2. Repetition number configuration is included in System Information Block Type 1 (SIB1) . Alternatively, a repetition number of the scheduling PDCCH of MSG2 is determined based on a repetition number of MSG1.

In one embodiment, the information of the DL channel comprises: Physical Downlink Shared Channel (PDSCH) of MSG2.

In some embodiments, repetition number configuration is included in corresponding Downlink Control Information (DCI) of the PDSCH of MSG2. Alternatively, a repetition number of the PDSCH of MSG2 is determined based on a repetition number of MSG1. Alternatively, a repetition number of the PDSCH of MSG2 is determined based on a Control Channel Element (CCE) aggregation level.

In some embodiments, the method may further include: receiving an indicator for indicating whether Demodulation Reference Signals (DMRS) of the at least one repetition of the PDSCH of MSG2 are enabled for joint channel estimation.

In some embodiments, the method may further include: determining a time relationship between MSG3 to be transmitted and the at least one repetition of the PDSCH of MSG2; and transmitting the MSG3 based on the determined time relationship. Specifically, the operation of determining the time relationship between MSG3 to be transmitted and the at least one repetition of the PDSCH of MSG2 may include: using a first repetition of the at least one repetition of the PDSCH of MSG2 as reference to determine the time relationship; or using any one of the at least one repetition of the PDSCH of MSG2 as reference to determine the time relationship; or dividing the at least one repetition of the PDSCH of MSG2 into multiple sub-sets, and using a first or last repetition of the PDSCH of MSG2 of each of the sub-sets as reference to determine the time relationship; or using a last repetition of the at least one repetition of the PDSCH of MSG2 as reference to determine the time relationship.

In one embodiment, the information of the DL channel comprises: scheduling Physical Downlink Control Channel (PDCCH) of MSG4.

In some embodiments, repetition number configuration is included in MSG1 or MSG3. Alternatively, a repetition number of the scheduling PDCCH of MSG4 is determined based on a repetition number of MSG3.

In one embodiment, the information of the DL channel comprises: Physical Downlink Shared Channel (PDSCH) of MSG4.

In some embodiments, repetition number configuration is included in corresponding Downlink Control Information (DCI) of the PDSCH of MSG4. Alternatively, a repetition number of the PDSCH of MSG4 is determined based on a repetition number of MSG3. Alternatively, a repetition number of the PDSCH of MSG4 is determined based on a Control Channel Element (CCE) aggregation level.

In some embodiments, the method may further include: determining a time relationship between HARQ-ACK feedback of MSG4 to be transmitted and the at least one repetition of the PDSCH of MSG4; and transmitting the HARQ-ACK feedback of MSG4 based on the determined time relationship. Specifically, the operation of determining the time relationship between HARQ-ACK feedback of MSG4 to be transmitted and the at least one repetition of the PDSCH of MSG4 comprises: using a first repetition of the at least one repetition of the PDSCH of MSG4 as reference to determine the time relationship; or using any one of the at least one repetition of the PDSCH of MSG4 as reference to determine the time relationship; or using a last repetition of the at least one repetition of the PDSCH of MSG4 as reference to determine the time relationship.

FIG. 10 is a flowchart of an enhancement method for a downlink (DL) channel in random access procedure according to yet another embodiment of the present disclosure. The method may be executed by a base station. The method includes operations described in Block S301. In S301, an information of the DL channel is transmitted across more than two symbols or slots.

According to the present embodiment, the enhancement method includes: transmitting an information of the DL channel across more than two symbols or slots. When cross-symbol/cross-slot transmission is enabled, low code rate for the DL channel can be adopted. Thus, the implementation of the method may enable cross-symbol/cross-slot transmission of the DL channel, and thus coverage capacity of the DL channel can be improved.

In one embodiment, the information of the DL channel comprises scheduling Downlink Control Information (DCI) of System Information Block Type 1 (SIB1) . Cross-symbol configuration of the scheduling DCI of SIB1 is included in configuration of Control Resource Set (CORESET) . The method may further include: transmitting an index of the configuration of CORESET, and determining a number of symbols that the scheduling DCI of SIB1 occupies based on the index of the configuration of CORESET.

In one embodiment, the information of the DL channel comprises System Information Block Type 1 (SIB1) Physical Downlink Shared Channel (PDSCH) . Cross-slot/cross-symbol configuration of the SIB1 PDSCH is included in corresponding Downlink Control Information (DCI) of the SIB1 PDSCH.

In some embodiments, the cross-slot/cross-symbol configuration of the SIB1 PDSCH is included in configuration of time domain resource allocation (TDRA) of the SIB1 PDSCH, and the method further comprises: transmitting an index of the configuration of TDRA of the SIB1 PDSCH; and determining a number of slots that the SIB1 PDSCH occupies based on the index of the configuration of TDRA of the SIB1 PDSCH. Alternatively, the cross-slot/cross-symbol configuration of the SIB1 PDSCH is indicated in a field of the corresponding DCI.

In one embodiment, the information of the DL channel comprises scheduling Physical Downlink Control Channel (PDCCH) of MSG2. Cross-slot/cross-symbol configuration of the PDCCH of MSG2 is included in System Information Block Type 1 (SIB1) .

In one embodiment, the information of the DL channel comprises: Physical Downlink Shared Channel (PDSCH) of MSG2. Cross-slot/cross-symbol configuration of the PDSCH of MSG2 is included in corresponding Downlink Control Information (DCI) of the PDSCH of MSG2.

In some embodiment, the cross-slot/cross-symbol configuration of the PDSCH of MSG2 is included in configuration of time domain resource allocation (TDRA) of the PDSCH of MSG2, and the method further comprises: transmitting an index of the configuration of TDRA of the PDSCH of MSG2; and determining a number of slots that the PDSCH of MSG2 occupies based on the index of the configuration of TDRA of the PDSCH of MSG2. Alternatively, the cross-slot/cross-symbol configuration of the PDSCH of MSG2 is indicated in a field of the corresponding DCI.

In one embodiment, the information of the DL channel comprises: scheduling Physical Downlink Control Channel (PDCCH) of MSG4. Cross-slot/cross-symbol configuration of the PDCCH of MSG4 is included in System Information Block Type 1 (SIB1) or MSG3.

In one embodiment, the information of the DL channel comprises: Physical Downlink Shared Channel (PDSCH) of MSG4. Cross-slot/cross-symbol configuration of the PDSCH of MSG4 is included in corresponding Downlink Control Information (DCI) of the PDSCH of MSG4.

In some embodiment, the cross-slot/cross-symbol configuration of the PDSCH of MSG4 is included in configuration of time domain resource allocation (TDRA) of the PDSCH of MSG4, and the method further comprises: transmitting an index of the configuration of TDRA of the PDSCH of MSG4; and determining a number of slots that the PDSCH of MSG4 occupies based on the index of the configuration of TDRA of the PDSCH of MSG4. Alternatively, the cross-slot/cross-symbol configuration of the PDSCH of MSG4 is indicated in a field of the corresponding DCI.

FIG. 11 is a flowchart of an enhancement method for a downlink (DL) channel in random access procedure according to another embodiment of the present disclosure. The method may be executed by a user equipment or a user device. The method includes operations described in Block S401. In S401, an information of the DL channel is received across more than two symbols or slots.

According to the present embodiment, the enhancement method includes: receiving an information of the DL channel across more than two symbols or slots. When cross-symbol/cross-slot transmission is enabled, low code rate for the DL channel can be adopted. Thus, the implementation of the method may enable cross-symbol/cross-slot transmission of the DL channel, and thus coverage capacity of the DL channel can be improved.

In one embodiment, the information of the DL channel comprises scheduling Downlink Control Information (DCI) of System Information Block Type 1 (SIB1) . Cross-symbol/cross-slot configuration of the scheduling DCI of SIB1 is included in configuration of Control Resource Set (CORESET) . The method may further include: receiving an index of the configuration of CORESET, and determining a number of symbols/slots that the scheduling DCI of SIB1 occupies based on the index of the configuration of CORESET.

FIG. 12 conceptually illustrates a communication device 500 with which some embodiments of the invention are implemented. The communication device 500 may be a computer (e.g., a desktop computer, personal computer, tablet computer, etc. ) , phone, PDA, or any other sort of electronic device. The communication device 500 may be, for example, a base station or a user equipment. Such an apparatus includes various types of computer readable media and interfaces for various other types of computer readable media. The device 500 includes a processor 501, a memory 502, and a transceiver 503. The transceiver 503 is configured to transmit or receive communication signals. The memory 502 is configured to store executable instructions that, when executed by the processor 501, cause the processor 501 to perform any one of the foregoing enhancement methods for a downlink (DL) channel in random access procedure.

The processor 602 may be a single processor or a multi-core processor in different embodiments. In some embodiments, the processor may include a GPU, NPU or DSP which may offload various computations or complement the image processing provided by the processor 702.

Some embodiments include electronic components, such as microprocessors, storage and memory that store computer program instructions in a machine-readable or computer-readable medium (alternatively referred to as computer-readable storage media, machine-readable media, or machine-readable storage media) . Some examples of such computer-readable media include RAM, ROM, read-only compact discs (CD-ROM) , recordable compact discs (CD-R) , rewritable compact discs (CD-RW) , read-only digital versatile discs (e.g., DVD-ROM, dual-layer DVD-ROM) , a variety of recordable/rewritable DVDs (e.g., DVD-RAM, DVD-RW, DVD+RW, etc. ) , flash memory (e.g., SD cards, mini-SD cards, micro-SD cards, etc. ) , magnetic and/or solid state hard drives, read-only and recordablediscs, ultra density optical discs, any other optical or magnetic media, and floppy disks. The computer-readable media may store a computer program that is executable by at least one processing unit and includes sets of instructions for performing various operations. Examples of computer programs or computer code include machine code, such as is produced by a compiler, and files including higher-level code that are executed by a computer, an electronic component, or a microprocessor using an interpreter.

In this disclosure, the base station is an entity used to transmit or receive information, such as a gNB. The base station can also be an eNodeB, transmission reception point, TRP, the NodeB in next-generation communication, or an access point in WIFI.

The user equipment is an entity used to transmit or receive information on the user side, such as a cell phone or UE. The UE can also be referred to as a terminal, mobile station, or mobile terminal. The UE can be a mobile phone, pad, VR, AR, wireless terminal of industrial control, wireless terminal of self-driving, wireless terminal of remote medical surgery, wireless terminal of smart grid, wireless terminal of transport safety, wireless terminal of smart city, wireless terminal of smart home, etc.

Furthermore, the terminal and base station can be deployed on land, including indoor, outdoor, handheld, on-board. They can also be deployed on water, in the air, on a plane, drone, or satellite.

While the above discussion primarily refers to microprocessor or multi-core processors that execute software, some embodiments are performed by one or more integrated circuits, such as application specific integrated circuits (ASICs) or field programmable gate arrays (FPGAs) . In some embodiments, such integrated circuits execute instructions that are stored on the circuit itself. In addition, some embodiments execute software stored in programmable logic devices (PLDs) , ROM, or RAM devices.

As used in this specification and any claims of this application, the terms “computer” , “server” , “processor” , and “memory” all refer to electronic or other technological devices. These terms exclude people or groups of people. As used in this specification and any claims of this application, the terms “computer readable medium, ” “computer readable media, ” and “machine readable medium” are entirely restricted to tangible, physical objects that store information in a form that is readable by a computer. These terms exclude any wireless signals, wired download signals, and any other ephemeral signals.

The present disclosure further provides a computer readable media which is configured to store executable instructions. When the instructions are executed by a processor, the processor may perform any one of the foregoing methods and processes. Many of the above-described features and applications are implemented as software processes that are specified as a set of instructions recorded on a computer readable storage medium (also referred to as computer readable medium) . When these instructions are executed by one or more computational or processing unit (s) (e.g., one or more processors, cores of processors, or other processing units) , they cause the processing unit (s) to perform the actions indicated in the instructions. Examples of computer readable media include, but are not limited to, CD-ROMs, flash drives, random access memory (RAM) chips, hard drives, erasable programmable read only memories (EPROMs) , electrically erasable programmable read-only memories (EEPROMs) , etc. The computer readable media does not include carrier waves and electronic signals passing wirelessly or over wired connections.

In this specification, the term “software” is meant to include firmware residing in read-only memory or applications stored in magnetic storage which can be read into memory for processing by a processor. Also, in some embodiments, multiple software inventions can be implemented as sub-parts of a larger program while remaining distinct software inventions. In some embodiments, multiple software inventions can also be implemented as separate programs. Finally, any combination of separate programs that together implement a software invention described here is within the scope of the invention. In some embodiments, the software programs, when installed to operate on one or more electronic systems, define one or more specific machine implementations that execute and perform the operations of the software programs.

While the disclosure has been described with reference to numerous specific details, one of ordinary skill in the art will recognize that the invention can be embodied in other specific forms without departing from the spirit of the invention. In addition, a number of the figures conceptually illustrate processes and methods. The specific operations of these processes may not be performed in the exact order shown and described. The specific operations may not be performed in one continuous series of operations, and different specific operations may be performed in different embodiments. Furthermore, the process could be implemented using several sub-processes, or as part of a larger macro process.

The foregoing is merely embodiments of the present disclosure, and is not intended to limit the scope of the disclosure. Any transformation of equivalent structure or equivalent process which uses the specification and the accompanying drawings of the present disclosure, or directly or indirectly application in other related technical fields, are likewise included within the scope of the protection of the present disclosure.

Claims

An enhancement method for a downlink (DL) channel, executed by a base station, comprising:

transmitting an information of the DL channel; and

transmitting at least one repetition of the information of the DL channel.
The method of claim 1, wherein the information of the DL channel comprises scheduling Downlink Control Information (DCI) of System Information Block Type 1 (SIB1) .
The method of claim 2, wherein repetition number configuration of the scheduling DCI of SIB1is included in configuration of Control Resource Set (CORESET) , and the method further comprises:

transmitting an index of the configuration of CORESET, and

determining a repetition number of the at least one repetition based on the index of the configuration of CORESET.
The method of claim 1, wherein the information of the DL channel comprises System Information Block Type 1 (SIB1) Physical Downlink Shared Channel (PDSCH) .
The method of claim 4, wherein repetition number configuration of the SIB1 PDSCH is included in corresponding Downlink Control Information (DCI) of the SIB1 PDSCH.
The method of claim 5, wherein the repetition number configuration of the SIB1 PDSCH is included in configuration of time domain resource allocation (TDRA) of the SIB1 PDSCH, and the method further comprises:

transmitting an index of the configuration of TDRA of the SIB1 PDSCH; and

determining a repetition number of the at least one repetition based on the index of the configuration of TDRA of the SIB1 PDSCH.
The method of claim 5, wherein the repetition number configuration of the SIB1 PDSCH is indicated in a field of the corresponding DCI.
The method of claim 4, further comprising:

transmitting an indicator for indicating whether Demodulation Reference Signals (DMRS) of the at least one repetition of the SIB1 PDSCH are enabled for joint channel estimation.
The method of claim 1, wherein the information of the DL channel comprises scheduling Physical Downlink Control Channel (PDCCH) of MSG2.
The method of claim 9, wherein repetition number configuration is included in System Information Block Type 1 (SIB1) .
The method of claim 9, wherein a repetition number of the scheduling PDCCH of MSG2 is determined based on a repetition number of MSG1.
The method of claim 1, wherein the information of the DL channel comprises: Physical Downlink Shared Channel (PDSCH) of MSG2.
The method of claim 12, wherein repetition number configuration is included in corresponding Downlink Control Information (DCI) of the PDSCH of MSG2.
The method of claim 13, wherein the repetition number configuration is included in configuration of time domain resource allocation (TDRA) of the PDSCH of MSG2, and the method further comprises:

transmitting an index of the configuration of TDRA of the PDSCH of MSG2; and

determining a repetition number of the at least one repetition based on the index of the configuration of TDRA of the PDSCH of MSG2.
The method of claim 13, wherein the repetition number configuration is indicated in a field of the corresponding DCI.
The method of claim 12, wherein a repetition number of the PDSCH of MSG2 is determined based on a repetition number of MSG1.
The method of claim 12, wherein a repetition number of the PDSCH of MSG2 is determined based on a Control Channel Element (CCE) aggregation level.
The method of claim 12, further comprising:

transmitting an indicator for indicating whether Demodulation Reference Signals (DMRS) of the at least one repetition of the PDSCH of MSG2 are enabled for joint channel estimation.
The method of claim 12, further comprising:

determining a time relationship between MSG3 to be received and the at least one repetition of the PDSCH of MSG2; and

receiving the MSG3 based on the determined time relationship.
The method of claim 19, wherein the determining the time relationship between MSG3 to be received and the at least one repetition of the PDSCH of MSG2 comprises:

using a first repetition of the at least one repetition of the PDSCH of MSG2 as reference to determine the time relationship; or

using any one of the at least one repetition of the PDSCH of MSG2 as reference to determine the time relationship; or

dividing the at least one repetition of the PDSCH of MSG2 into multiple sub-sets, and using a first or last repetition of the PDSCH of MSG2 of each of the sub-sets as reference to determine the time relationship; or

using a last repetition of the at least one repetition of the PDSCH of MSG2 as reference to determine the time relationship.
The method of claim 1, wherein the information of the DL channel comprises: scheduling Physical Downlink Control Channel (PDCCH) of MSG4.
The method of claim 21, wherein repetition number configuration is included in MSG1 or MSG3.
The method of claim 21, wherein a repetition number of the scheduling PDCCH of MSG4 is determined based on a repetition number of MSG3.
The method of claim 1, wherein the information of the DL channel comprises: Physical Downlink Shared Channel (PDSCH) of MSG4.
The method of claim 24, wherein repetition number configuration is included in corresponding Downlink Control Information (DCI) of the PDSCH of MSG4.
The method of claim 25, wherein the repetition number configuration is included in configuration of time domain resource allocation (TDRA) of the PDSCH of MSG4, and the method further comprises:

transmitting an index of the configuration of TDRA of the PDSCH of MSG4; and

determining a repetition number of the at least one repetition based on the index of the configuration of TDRA of the PDSCH of MSG4.
The method of claim 25, wherein the repetition number configuration is indicated in a field of the corresponding DCI.
The method of claim 24, wherein a repetition number of the PDSCH of MSG4 is determined based on a repetition number of MSG3.
The method of claim 24, wherein a repetition number of the PDSCH of MSG4 is determined based on a Control Channel Element (CCE) aggregation level.
The method of claim 24, further comprising:

transmitting an indicator for indicating whether Demodulation Reference Signals (DMRS) of the at least one repetition of the PDSCH of MSG2 are enabled for joint channel estimation.
The method of claim 24, further comprising:

determining a time relationship between HARQ-ACK feedback of MSG4 to be received and the at least one repetition of the PDSCH of MSG4; and

receiving the HARQ-ACK feedback of MSG4 based on the determined time relationship.
The method of claim 31, wherein the determining the time relationship between HARQ-ACK feedback of MSG4 to be received and the at least one repetition of the PDSCH of MSG4 comprises:

using a first repetition of the at least one repetition of the PDSCH of MSG4 as reference to determine the time relationship; or

using any one of the at least one repetition of the PDSCH of MSG4 as reference to determine the time relationship; or

using a last repetition of the at least one repetition of the PDSCH of MSG4 as reference to determine the time relationship.
An enhancement method for a downlink (DL) channel, executed by a user equipment (UE) , comprising:

receiving an information of the DL channel; and

receiving at least one repetition of the information of the DL channel.
The method of claim 33, wherein the information of the DL channel comprises scheduling Downlink Control Information (DCI) of System Information Block Type 1 (SIB1) .
The method of claim 34, wherein repetition number configuration is included in configuration of Control Resource Set (CORESET) , and the method further comprises:

receiving an index of the configuration of CORESET, and

determining a repetition number of the at least one repetition based on the index of the configuration of CORESET.
The method of claim 33, wherein the information of the DL channel comprises System Information Block Type 1 (SIB1) Physical Downlink Shared Channel (PDSCH) .
The method of claim 36, wherein repetition number configuration is included in corresponding Downlink Control Information (DCI) of the SIB1 PDSCH.
The method of claim 36, further comprising:

receiving an indicator for indicating whether Demodulation Reference Signals (DMRS) of the at least one repetition of the SIB1 PDSCH are enabled for joint channel estimation.
The method of claim 33, wherein the information of the DL channel comprises scheduling Physical Downlink Control Channel (PDCCH) of MSG2.
The method of claim 39, wherein repetition number configuration is included in System Information Block Type 1 (SIB1) .
The method of claim 39, wherein a repetition number of the scheduling PDCCH of MSG2 is determined based on a repetition number of MSG1.
The method of claim 33, wherein the information of the DL channel comprises: Physical Downlink Shared Channel (PDSCH) of MSG2.
The method of claim 42, wherein repetition number configuration is included in corresponding Downlink Control Information (DCI) of the PDSCH of MSG2.
The method of claim 42, wherein a repetition number of the PDSCH of MSG2 is determined based on a repetition number of MSG1.
The method of claim 42, wherein a repetition number of the PDSCH of MSG2 is determined based on a Control Channel Element (CCE) aggregation level.
The method of claim 42, further comprising:

receiving an indicator for indicating whether Demodulation Reference Signals (DMRS) of the at least one repetition of the PDSCH of MSG2 are enabled for joint channel estimation.
The method of claim 42, further comprising:

determining a time relationship between MSG3 to be transmitted and the at least one repetition of the PDSCH of MSG2; and

transmitting the MSG3 based on the determined time relationship.
The method of claim 47, wherein the determining the time relationship between MSG3 to be transmitted and the at least one repetition of the PDSCH of MSG2 comprises:

using a first repetition of the at least one repetition of the PDSCH of MSG2 as reference to determine the time relationship; or

using any one of the at least one repetition of the PDSCH of MSG2 as reference to determine the time relationship; or

dividing the at least one repetition of the PDSCH of MSG2 into multiple sub-sets, and using a first or last repetition of the PDSCH of MSG2 of each of the sub-sets as reference to determine the time relationship; or

using a last repetition of the at least one repetition of the PDSCH of MSG2 as reference to determine the time relationship.
The method of claim 33, wherein the information of the DL channel comprises: scheduling Physical Downlink Control Channel (PDCCH) of MSG4.
The method of claim 49, wherein repetition number configuration is included in MSG1 or MSG3.
The method of claim 49, wherein a repetition number of the scheduling PDCCH of MSG4 is determined based on a repetition number of MSG3.
The method of claim 33, wherein the information of the DL channel comprises: Physical Downlink Shared Channel (PDSCH) of MSG4.
The method of claim 52, wherein repetition number configuration is included in corresponding Downlink Control Information (DCI) of the PDSCH of MSG4.
The method of claim 52, wherein a repetition number of the PDSCH of MSG4 is determined based on a repetition number of MSG3.
The method of claim 52, wherein a repetition number of the PDSCH of MSG4 is determined based on a Control Channel Element (CCE) aggregation level.
The method of claim 52, further comprising:

receiving an indicator for indicating whether Demodulation Reference Signals (DMRS) of the at least one repetition of the PDSCH of MSG2 are enabled for joint channel estimation.
The method of claim 52, further comprising:

determining a time relationship between HARQ-ACK feedback of MSG4 to be transmitted and the at least one repetition of the PDSCH of MSG4; and

transmitting the HARQ-ACK feedback of MSG4 based on the determined time relationship.
The method of claim 57, wherein the determining the time relationship between HARQ-ACK feedback of MSG4 to be transmitted and the at least one repetition of the PDSCH of MSG4 comprises:

using a first repetition of the at least one repetition of the PDSCH of MSG4 as reference to determine the time relationship; or

using any one of the at least one repetition of the PDSCH of MSG4 as reference to determine the time relationship; or

using a last repetition of the at least one repetition of the PDSCH of MSG4 as reference to determine the time relationship.
An enhancement method for a downlink (DL) channel in random access procedure, executed by a base station, comprising:

transmitting an information of the DL channel across more than two symbols or slots.
The method of claim 59,

wherein the information of the DL channel comprises scheduling Downlink Control Information (DCI) of System Information Block Type 1 (SIB1) ;

wherein cross-symbol configuration of the scheduling DCI of SIB1 is included in configuration of Control Resource Set (CORESET) ;

wherein the method further comprises: transmitting an index of the configuration of CORESET, and determining a number of symbols that the scheduling DCI of SIB1 occupies based on the index of the configuration of CORESET.
The method of claim 59,

wherein the information of the DL channel comprises System Information Block Type 1 (SIB1) Physical Downlink Shared Channel (PDSCH) ;

wherein cross-slot/cross-symbol configuration of the SIB1 PDSCH is included in corresponding Downlink Control Information (DCI) of the SIB1 PDSCH.
The method of claim 61, wherein the cross-slot/cross-symbol configuration of the SIB1 PDSCH is included in configuration of time domain resource allocation (TDRA) of the SIB1 PDSCH, and the method further comprises:

transmitting an index of the configuration of TDRA of the SIB1 PDSCH; and

determining a number of slots that the SIB1 PDSCH occupies based on the index of the configuration of TDRA of the SIB1 PDSCH.
The method of claim 61, wherein the cross-slot/cross-symbol configuration of the SIB1 PDSCH is indicated in a field of the corresponding DCI.
The method of claim 59,

wherein the information of the DL channel comprises scheduling Physical Downlink Control Channel (PDCCH) of MSG2;

wherein cross-slot/cross-symbol configuration of the PDCCH of MSG2 is included in System Information Block Type 1 (SIB1) .
The method of claim 59,

wherein the information of the DL channel comprises: Physical Downlink Shared Channel (PDSCH) of MSG2;

wherein cross-slot/cross-symbol configuration of the PDSCH of MSG2 is included in corresponding Downlink Control Information (DCI) of the PDSCH of MSG2.
The method of claim 65, wherein the cross-slot/cross-symbol configuration of the PDSCH of MSG2 is included in configuration of time domain resource allocation (TDRA) of the PDSCH of MSG2, and the method further comprises:

transmitting an index of the configuration of TDRA of the PDSCH of MSG2; and

determining a number of slots that the PDSCH of MSG2 occupies based on the index of the configuration of TDRA of the PDSCH of MSG2.
The method of claim 65, wherein the cross-slot/cross-symbol configuration of the PDSCH of MSG2 is indicated in a field of the corresponding DCI.
The method of claim 59,

wherein the information of the DL channel comprises: scheduling Physical Downlink Control Channel (PDCCH) of MSG4;

wherein cross-slot/cross-symbol configuration of the PDCCH of MSG4 is included in System Information Block Type 1 (SIB1) or MSG3.
The method of claim 59,

wherein the information of the DL channel comprises: Physical Downlink Shared Channel (PDSCH) of MSG4;

wherein cross-slot/cross-symbol configuration of the PDSCH of MSG4 is included in corresponding Downlink Control Information (DCI) of the PDSCH of MSG4.
The method of claim 69, wherein the cross-slot/cross-symbol configuration of the PDSCH of MSG4 is included in configuration of time domain resource allocation (TDRA) of the PDSCH of MSG4, and the method further comprises:

transmitting an index of the configuration of TDRA of the PDSCH of MSG4; and

determining a number of slots that the PDSCH of MSG4 occupies based on the index of the configuration of TDRA of the PDSCH of MSG4.
The method of claim 69, wherein the cross-slot/cross-symbol configuration of the PDSCH of MSG4 is indicated in a field of the corresponding DCI.
An enhancement method for a downlink (DL) channel in random access procedure, executed by a user equipment (UE) , comprising:

receiving an information of the DL channel across more than two symbols or slots.
The method of claim 72,

wherein the information of the DL channel comprises scheduling Downlink Control Information (DCI) of System Information Block Type 1 (SIB1) ;

wherein cross-symbol/cross-slot configuration of the scheduling DCI of SIB1 is included in configuration of Control Resource Set (CORESET) ;

wherein the method further comprises: receiving an index of the configuration of CORESET, and determining a number of symbols/slots that the scheduling DCI of SIB1 occupies based on the index of the configuration of CORESET.
The method of claim 72,

wherein the information of the DL channel comprises System Information Block Type 1 (SIB1) Physical Downlink Shared Channel (PDSCH) ;

wherein cross-slot/cross-symbol configuration of the SIB1 PDSCH is included in corresponding Downlink Control Information (DCI) of the SIB1 PDSCH.
The method of claim 72,

wherein the information of the DL channel comprises scheduling Physical Downlink Control Channel (PDCCH) of MSG2;

wherein cross-slot/cross-symbol configuration of the PDCCH of MSG2 is included in System Information Block Type 1 (SIB1) .
The method of claim 72,

wherein the information of the DL channel comprises: Physical Downlink Shared Channel (PDSCH) of MSG2;

wherein cross-slot/cross-symbol configuration of the PDSCH of MSG2 is included in corresponding Downlink Control Information (DCI) of the PDSCH of MSG2.
The method of claim 72,

wherein the information of the DL channel comprises: scheduling Physical Downlink Control Channel (PDCCH) of MSG4;

wherein cross-slot/cross-symbol configuration of the PDCCH of MSG4 is included in System Information Block Type 1 (SIB1) or MSG3.
The method of claim 72,

wherein the information of the DL channel comprises: Physical Downlink Shared Channel (PDSCH) of MSG4;

wherein cross-slot/cross-symbol configuration of the PDSCH of MSG4 is included in corresponding Downlink Control Information (DCI) of the PDSCH of MSG4.
A communication device, comprising a transceiver, a processor and a memory;

wherein the transceiver is configured to transmit or receive a signal;

wherein the memory is configured to store program instruction, which when executed by the processor, causes the processor to perform the method of any of the claims 1 to 78.
A computer readable media storing program instructions that, when executed by a processor, cause the processor to perform the method of any of the claims 1 to 78.