EP4144175A1

EP4144175A1 - Methods and devices for facilitating random access

Info

Publication number: EP4144175A1
Application number: EP21724811.1A
Authority: EP
Inventors: Jingya Li; Zhipeng LIN; Henrik Sahlin
Original assignee: Telefonaktiebolaget LM Ericsson AB
Current assignee: Telefonaktiebolaget LM Ericsson AB
Priority date: 2020-04-29
Filing date: 2021-04-29
Publication date: 2023-03-08
Also published as: WO2021221558A1

Abstract

The present disclosure provides a method (200) in a network device. The method (200) includes: configuring (210) a Random Access Response, RAR, repetition for a terminal device configured with a prioritized service, a network slice associated with the prioritized service, or a prioritized radio access network type.

Description

METHODS AND DEVICES FOR FACILITATING RANDOM ACCESS

TECHNICAL FIELD

The present disclosure relates to wireless communication, and more particularly, to a network device, a terminal device, and methods therein for facilitating random access.

BACKGROUND

A terminal device, or User Equipment (UE), needs to carry out cell search to find, synchronize with, and identify a cell before it can properly communicate within a network. Then, the terminal device can acquire basic system information and perform a random access procedure to establish a connection to the cell.

In the 5^th Generation (5G) network or New Radio (NR), a combination of Synchronization Signal (SS) and Physical Broadcast Channel (PBCH) is referred to as an SS/PBCH Block (SSB). Similar to Long Term Evolution (LTE), a pair of SSs, i.e. , a Primary Synchronization Signal (PSS) and a Secondary Synchronization Signal (SSS), are periodically transmitted from each cell to allow a UE to initially access to the network. By detecting the SSs, a UE can obtain a physical cell identity, achieve downlink synchronization in both time and frequency, and acquire the timing for a PBCH. The PBCH carries a Master Information Block (MIB), which contains minimum system information the UE needs to acquire System Information Block 1 (SIB1). The SIB1 carries remaining minimum system information that is needed for the UE to perform a subsequent random access procedure.

Fig. 1 A shows a four-step random access produce. At 111, for initial access, a UE initiates the random access procedure by transmitting a random access preamble (Msg1) on a Physical Random Access Channel (PRACH) to a network device, e.g., a (next) generation NodeB (gNB). In NR, the time-frequency resource on which the random access preamble is transmitted is defined as a PRACH occasion. There are up to 64 sequences that can be used as random access preambles per PRACH occasion in each cell. Aset of random access preambles transmitted on a PRACH occasion can be mapped to an SSB index or SSB beam. After detecting the Msg1 , the gNB responds at 112 by transmitting a Random Access Response (RAR) (Msg2) to the UE on a Physical Downlink Shared Channel (PDSCH). The PDSCH carrying the RAR is scheduled by a Physical Downlink Control Channel (PDCCH) carrying Downlink Control Information (DCI) Format 1_0 with Cyclic Redundancy Check (CRC) scrambled by a Random Access - Radio Network Temporary Identifier (RA-RNTI). The RA-RNTI is associated with the PRACH occasion in which the random access preamble is detected. If multiple preambles from multiple UEs are detected by the gNB on the same PRACH occasion, the Msg2 carried on the PDSCH may consist of multiple RARs each for one random access preamble and including a Random Access Preamble Identifier (RAPID) of the random access preamble.

The UE derives its corresponding RA-RNTI based on the PRACH occasion selected for its preamble transmission. After transmitting the random access preamble, the UE starts monitoring PDCCH candidates in a Typel - PDCCH Common Search Space (CSS) set for DCI Format 1_0 with CRC scrambled by the corresponding RA-RNTI within a time window, which is provided by the parameter ra-ResponseWindow in the SIB1. If the UE detects a PDCCH with its corresponding RA-RNTI within the RAR window and if it successfully decodes the associated PDSCH carrying the Msg2, the UE checks whether a RAPID contained in an RAR in Msg2 matches its selected preamble. If so, the UE considers this RAR reception successful; or otherwise, the UE can start a new random access attempt after the time window passes, until a Msg2 is received successfully or a maximum allowable number of preambles transmissions has reached.

At 113, after successfully decoding the Msg2, the UE continues the procedure by transmitting a Physical Uplink Shared Channel (PUSCH) (Msg3) to the gNB for terminal identification and Radio Resource Control (RRC) connection establishment request. At 114, the gNB transmits a PDSCH (Msg4) to the UE for contention resolution.

Fig. 1 B shows a two-step random access produce, also referred to as Type-2 random access procedure in the 3^rd Generation Partnership Project (3GPP) TS 38.213. At 121, a UE transmits a Message A (MsgA) to a gNB, including a random access preamble together with higher layer data such as an RRC connection request possibly with some small payload on PUSCH. After detecting the MsgA, at 122, the gNB transmits an RAR (Message B or MsgB) to the UE, including UE identifier assignment, timing advance information, and contention resolution message, etc. The RAR (MsgB) is carried by a PDSCH scheduled by a PDCCH with CRC scrambled by a MsgB-RNTI derived by adding a fixed offset to an RA-RNTI calculated based on the time-frequency resource of the PRACH occasion used for transmission of the preamble in the MsgA. The UE monitors the MsgB in an RAR window with a maximum length of 40ms after transmission of the MsgA.

As discussed above, before data transmission and reception, a UE needs to perform a random access procedure to establish an RRC connection to a gNB. For some high-priority services or applications, e.g., Mission Critical (MC) services, it is desired to adapt the random access procedure to ensure fast and reliable network connection establishment for UEs. For example, first responders, e.g., fire-fighters, polices and emergency medical service providers, require fast, reliable and secure communications in various MC situations. In disaster and emergency situations, first responders as well as other essential public safety service providers rely crucially on the availability of network services to coordinate their operations. Therefore, cellular coverage is extremely essential. Compared to e.g., enhanced Mobile Broadband (eMBB) services, the coverage requirements for public safety communications are stricter and they are typically defined as 99% of the population, 99% of landmass, 99.5% outdoor, 95% indoor, etc.

Further, among all downlink physical channels, a PDSCFI carrying an RAR (Msg2 or MsgB) may be the weakest one which limits the network coverage. Therefore, it is desired to improve the RAR (Msg2 or MsgB) transmission, especially for high-priority services, e.g., MC services.

SUMMARY

It is an object of the present disclosure to provide a network device, a terminal device, and methods therein, capable of improving RAR transmission for high- priority services, network slices associated with high-priority services, or high- priority radio access network types.

According to a first aspect of the present disclosure, a method in a network device is provided. The method includes: configuring an RAR repetition for a terminal device configured with a prioritized service, a network slice associated with the prioritized service, or a prioritized radio access network type.

In an embodiment, the operation of configuring may include: transmitting an indication of a number of RAR repetitions enabled for terminal devices configured with the prioritized service, the network slice associated with the prioritized service, or the prioritized radio access network type, via system information or PBCH.

In an embodiment, the operation of configuring may include: transmitting, to the terminal device, an indication of a number of RAR repetitions via dedicated RRC signaling.

In an embodiment, the method may further include: receiving, from the terminal device, a random access preamble; and determining that the terminal device is configured with the prioritized service, the network slice associated with the prioritized service, or the prioritized radio access network type. The operation of configuring may include, in response to the determining: transmitting, to the terminal device, an indication of a number of RAR repetitions in DCI.

In an embodiment, the method may further include: transmitting, to the terminal device, an RAR for the number of RAR repetitions.

In an embodiment, the prioritized service may include an MC service, a multimedia priority service, or a Small Data Transmission (SDT) service. The prioritized radio access network type may include Non-Territorial Network (NTN).

In an embodiment, the NTN may include a satellite network, a High-Altitude Platform Station (HAPS) network, or a base station network on an aerial vehicle.

According to a second aspect of the present disclosure, a method in a terminal device is provided. The method includes: receiving, from a network device, a configuration of an RAR repetition for a prioritized service, a network slice associated with the prioritized service, or a prioritized radio access network type. In an embodiment, the configuration may be received via system information or PBCH, and may include an indication of a number of RAR repetitions enabled for terminal devices configured with the prioritized service, the network slice associated with the prioritized service, or the prioritized radio access network type.

In an embodiment, the configuration may be received via dedicated RRC signaling and may include an indication of a number of RAR repetitions.

In an embodiment, the method may further include: transmitting, to the network device, a random access preamble. The configuration may be received via DCI and may include an indication of a number of RAR repetitions.

In an embodiment, the method may further include: receiving, from the network device, an RAR in at least one of the number of RAR repetitions.

In an embodiment, the prioritized service may include an MC service, a multimedia priority service, or an SDT service. The prioritized radio access network type may include NTN.

In an embodiment, the NTN may include a satellite network, a HAPS network, or a base station network on an aerial vehicle.

According to a third aspect of the present disclosure, a method in a network device is provided. The method includes: configuring a parameter for RAR transmission or reception for a terminal device configured with a service having a priority level, a network slice associated with the service, or a radio access network type having a network priority level.

In an embodiment, the parameter may include a first RAR window which is different from a second RAR window for RAR reception for another terminal device configured with another service having another priority level lower than the priority level, another network slice associated with the other service, or another radio access network type having another network priority level lower than the network priority level. In an embodiment, the first RAR window may be shorter than the second RAR window.

In an embodiment, the parameter may include: a first Transport Block (TB) scaling factor which is smaller than a second TB scaling factor for RAR transmission for another terminal device configured with another service having another priority level lower than the priority level, another network slice associated with the other service, or another radio access network type having another network priority level lower than the network priority level, and/or a first Modulation and Coding Scheme (MCS) index which is smaller than a second MCS index for RAR transmission for another terminal device configured with another service having another priority level lower than the priority level, another network slice associated with the other service, or another radio access network type having another network priority level lower than the network priority level.

In an embodiment, the parameter may include an indication of a first MCS table which has lower spectral efficiency than a second MCS table for RAR transmission for another terminal device configured with another service having another priority level lower than the priority level, another network slice associated with the other service, or another radio access network type having another network priority level lower than the network priority level.

In an embodiment, the parameter may indicate that an earliest usable downlink symbol or a p/2 Binary Phase Shift Keying (BPSK) modulation is to be used for RAR transmission.

In an embodiment, the method may further include: receiving, from the terminal device, a random access preamble; determining that the terminal device is configured with the service having the priority level, the network slice associated with the service, or the radio access network type having the network priority level; and transmitting, to the terminal device, an RAR in accordance with the parameter.

In an embodiment, the service may include an MC service, a multimedia priority service, or an SDT service. The radio access network type may include NTN. In an embodiment, the NTN may include a satellite network, a HAPS network, or a base station network on an aerial vehicle.

According to a fourth aspect of the present disclosure, a method in a network device is provided. The method includes: receiving, from a first terminal device configured with a first service having a first priority level, a first network slice associated with the first service, or a first radio access network type having a first network priority level, a first random access preamble mapped to a first SSB; and transmitting, to the first terminal device, a first RAR via a first SSB beam corresponding to the first SSB, or an SSB beam closer to the first SSB beam than a second SSB beam via which a second RAR for a second terminal device is transmitted, the second terminal device being configured with a second service having a second priority level lower than the first priority level, a second network slice associated with the second service, or a second radio access network type having a second network priority level lower than the first network priority level and having transmitted a second random access preamble mapped to the first SSB.

In an embodiment, the first service may include an MC service, a multimedia priority service, or an SDT service. The radio access network type may include NTN.

According to a fifth aspect of the present disclosure, a method in a terminal device is provided. The method includes: receiving, from a network device, a parameter for RAR transmission or reception for a service having a priority level, a network slice associated with the service, or a radio access network type having a network priority level.

In an embodiment, the parameter may include a first RAR window which is different from a second RAR window for RAR reception for another service having another priority level lower than the priority level, another network slice associated with the other service, or another radio access network type having another network priority level lower than the network priority level. In an embodiment, the first RAR window may be shorter than the second RAR window.

In an embodiment, the parameter may include: a first TB scaling factor which is smaller than a second TB scaling factor for RAR transmission for another service having another priority level lower than the priority level, another network slice associated with the other service, or another radio access network type having another network priority level lower than the network priority level, and/or a first MCS index which is smaller than a second MCS index for RAR transmission for another service having another priority level lower than the priority level, another network slice associated with the other service, or another radio access network type having another network priority level lower than the network priority level.

In an embodiment, the parameter may include an indication of a first MCS table which has lower spectral efficiency than a second MCS table for RAR transmission for another service having another priority level lower than the priority level, another network slice associated with the other service, or another radio access network type having another network priority level lower than the network priority level.

In an embodiment, the parameter may indicate that an earliest usable downlink symbol or a p/2 BPSK modulation is to be used for RAR transmission.

In an embodiment, the method may further include: receiving, from the network device, an RAR in accordance with the parameter.

In an embodiment, the service may include an MC service, a multimedia priority service, or an SDT service. The radio access network type may include NTN.

According to a sixth aspect of the present disclosure, a method in a network device is provided. The method includes: receiving a plurality of random access preambles from a plurality of terminal devices, respectively, in one random access occasion; and transmitting one or more RARs to one or more of the plurality of terminal devices based on priority levels of respective services or network priority levels of respective radio access network types, the plurality of terminal devices being configured with the respective services, network slices associated with the respective services, or the respective radio access network types.

In an embodiment, the operation of transmitting may include: transmitting an RAR message containing one or more RARs for one or more of the plurality of terminal devices that are configured with services each having a priority level higher than or equal to a priority level threshold, network slices each associated with a service having a priority level higher than or equal to the priority level threshold, or radio access network types each having a network priority level higher than or equal to a network priority level threshold.

In an embodiment, the operation of transmitting may further include: transmitting one or more further RAR messages each containing one or more RARs for one or more of the plurality of terminal devices that are configured with services having one of the priority levels that is lower than the priority level threshold or network slices associated with services having one of the priority levels that is lower than the priority level threshold, in a descending order of the priority levels, until a maximum number of admissible terminal devices is reached, or transmitting one or more further RAR messages each containing one or more RARs for one or more of the plurality of terminal devices that are configured with radio access network types having one of the network priority levels that is lower than the network priority level threshold, in a descending order of the network priority levels, until a maximum number of admissible terminal devices is reached.

In an embodiment, the operation of transmitting may include: transmitting an RAR message obtained by adding RARs for the plurality of terminal devices, in a descending order of the priority levels or the network priority levels, until a maximum number of allowable RARs in one RAR message or a maximum number of admissible terminal devices is reached.

In an embodiment, the plurality of random access preambles may be mapped to different SSBs. The operation transmitting may include: transmitting the one or more RARs to the one or more terminal devices via one SSB beam corresponding to an SSB to which the random access preamble from one of the plurality of terminal devices that is configured with a service having a highest priority level among the priority levels, a network slice associated with the service having the highest priority level, or a radio access network type having a highest priority level among the network priority levels is mapped, or a beam quasi-colocated with the one SSB beam.

In an embodiment, the method may further include: transmitting DCI for scheduling the one or more RARs to the one or more terminal devices via the one SSB beam or a beam quasi-co-located with the one SSB beam.

According to a seventh aspect of the present disclosure, a method in a terminal device is provided. The method include: transmitting, to a network device, a random access preamble; monitoring DCI from the network device for scheduling an RAR message; determining that the RAR message does not contain an RAR for the terminal device; and monitoring, within an RAR window, further DCI from the network device for scheduling a further RAR message.

In an embodiment, the DCI and the further DCI may be addressed to an RNTI associated with a random access occasion in which the random access preamble is transmitted.

According to an eighth aspect of the present disclosure, a network device is provided. The network device includes a transceiver, a processor and a memory. The memory contains instructions executable by the processor whereby the network device is operative to perform the method according to any of the above first, third, fourth and sixth aspects.

According to a ninth aspect of the present disclosure, a computer readable storage medium is provided. The computer readable storage medium has computer program instructions stored thereon. The computer program instructions, when executed by a processor in a network device, cause the network device to perform the method according to any of the above first, third, fourth and sixth aspects. According to a tenth aspect of the present disclosure, a terminal device is provided. The terminal device includes a transceiver, a processor and a memory. The memory contains instructions executable by the processor whereby the terminal device is operative to perform the method according to any of the above second, fifth and seventh aspects.

According to an eleventh aspect of the present disclosure, a computer readable storage medium is provided. The computer readable storage medium has computer program instructions stored thereon. The computer program instructions, when executed by a processor in a terminal device, cause the terminal device to perform the method according to any of the above second, fifth and seventh aspects.

With the embodiments of the present disclosure, for a terminal device configured with a high-priority service, a network slice associated with a high-priority service, or a high-priority radio access network type, various mechanisms, e.g., RAR repetition, RAR transmission/reception parameter configuration, beam selection, etc., can be used for achieving an enhanced reliability and/or a reduced latency for an RAR transmission.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other objects, features and advantages will be more apparent from the following description of embodiments with reference to the figures, in which:

Fig. 1 A is a sequence diagram showing a four-step random access procedure;

Fig. 1 B is a sequence diagram showing a two-step random access procedure;

Fig. 2 is a flowchart illustrating a method in a network device according to an embodiment of the present disclosure;

Fig. 3 is a flowchart illustrating a method in a network device according to another embodiment of the present disclosure;

Fig. 4 is a flowchart illustrating a method in a network device according to yet another embodiment of the present disclosure;

Fig. 5 is a flowchart illustrating a method in a network device according to still another embodiment of the present disclosure; Fig. 6 is a flowchart illustrating a method in a terminal device according to an embodiment of the present disclosure;

Fig. 7 is a flowchart illustrating a method in a terminal device according to another embodiment of the present disclosure;

Fig. 8 is a flowchart illustrating a method in a terminal device according to yet another embodiment of the present disclosure;

Fig. 9 is a block diagram of a network device according to an embodiment of the present disclosure;

Fig. 10 is a block diagram of a network device according to another embodiment of the present disclosure;

Fig. 11 is a block diagram of a terminal device according to another embodiment of the present disclosure;

Fig. 12 is a block diagram of a terminal device according to another embodiment of the present disclosure;

Fig. 13 schematically illustrates a telecommunication network connected via an intermediate network to a host computer;

Fig. 14 is a generalized block diagram of a host computer communicating via a base station with a user equipment over a partially wireless connection; and

Figs. 15 to 18 are flowcharts illustrating methods implemented in a communication system including a host computer, a base station and a user equipment.

DETAILED DESCRIPTION

As used herein, the term "wireless communication network" refers to a network following any suitable communication standards, such as NR, LTE-Advanced

(LTE-A), LTE, Wideband Code Division Multiple Access (WCDMA), Fligh-Speed

Packet Access (HSPA), and so on. Furthermore, the communications between a terminal device and a network device in the wireless communication network may be performed according to any suitable generation communication protocols, including, but not limited to, Global System for Mobile Communications (GSM),

Universal Mobile Telecommunications System (UMTS), Long Term Evolution

(LTE), and/or other suitable 1G (the first generation), 2G (the second generation),

2.5G, 2.75G, 3G (the third generation), 4G (the fourth generation), 4.5G, 5G (the fifth generation) communication protocols, wireless local area network (WLAN) standards, such as the IEEE 802.11 standards; and/or any other appropriate wireless communication standard, such as the Worldwide Interoperability for Microwave Access (WiMax), Bluetooth, and/or ZigBee standards, and/or any other protocols either currently known or to be developed in the future.

The term “network node” or "network device" refers to a device in a wireless communication network via which a terminal device accesses the network and receives services therefrom. The network node or network device refers to a base station (BS), an access point (AP), or any other suitable device in the wireless communication network. The BS may be, for example, a node B (NodeB or NB), an evolved NodeB (eNodeB or eNB), or gNB, a Remote Radio Unit (RRU), a radio header (RH), a remote radio head (RRH), a relay, a low power node such as a femto, a pico, and so forth. Yet further examples of the network device may include multi-standard radio (MSR) radio equipment such as MSR BSs, network controllers such as radio network controllers (RNCs) or base station controllers (BSCs), base transceiver stations (BTSs), transmission points, transmission nodes. More generally, however, the network device may represent any suitable device (or group of devices) capable, configured, arranged, and/or operable to enable and/or provide a terminal device access to the wireless communication network or to provide some service to a terminal device that has accessed the wireless communication network.

The term "terminal device" refers to any end device that can access a wireless communication network and receive services therefrom. By way of example and not limitation, the terminal device refers to a mobile terminal, user equipment (UE), or other suitable devices. The UE may be, for example, a Subscriber Station (SS), a Portable Subscriber Station, a Mobile Station (MS), or an Access Terminal (AT). The terminal device may include, but not limited to, portable computers, desktop computers, image capture terminal devices such as digital cameras, gaming terminal devices, music storage and playback appliances, a mobile phone, a cellular phone, a smart phone, voice over IP (VoIP) phones, wireless local loop phones, tablets, personal digital assistants (PDAs), wearable terminal devices, vehicle-mounted wireless terminal devices, wireless endpoints, mobile stations, laptop-embedded equipment (LEE), laptop-mounted equipment (LME), USB dongles, smart devices, wireless customer-premises equipment (CPE) and the like. In the following description, the terms "terminal device", "terminal", "user equipment" and "UE" may be used interchangeably. As one example, a terminal device may represent a UE configured for communication in accordance with one or more communication standards promulgated by the 3rd Generation Partnership Project (3GPP), such as 3GPP's GSM, UMTS, LTE, and/or 5G standards. As used herein, a "user equipment" or "UE" may not necessarily have a "user" in the sense of a human user who owns and/or operates the relevant device. In some embodiments, a terminal device may be configured to transmit and/or receive information without direct human interaction. For instance, a terminal device may be designed to transmit information to a network on a predetermined schedule, when triggered by an internal or external event, or in response to requests from the wireless communication network. Instead, a UE may represent a device that is intended for sale to, or operation by, a human user but that may not initially be associated with a specific human user.

The terminal device may support device-to-device (D2D) communication, for example by implementing a 3GPP standard for sidelink communication, and may in this case be referred to as a D2D communication device.

As yet another example, in an Internet of Things (IOT) scenario, a terminal device may represent a machine or other device that performs monitoring and/or measurements, and transmits the results of such monitoring and/or measurements to another terminal device and/or network equipment. The terminal device may in this case be a machine-to-machine (M2M) device, which may in a 3GPP context be referred to as a machine-type communication (MTC) device. As one particular example, the terminal device may be a UE implementing the 3GPP narrow band internet of things (NB-loT) standard. Particular examples of such machines or devices are sensors, metering devices such as power meters, industrial machinery, or home or personal appliances, for example refrigerators, televisions, personal wearables such as watches etc. In other scenarios, a terminal device may represent a vehicle or other equipment that is capable of monitoring and/or reporting on its operational status or other functions associated with its operation.

As used herein, a downlink transmission refers to a transmission from a network device to a terminal device, and an uplink transmission refers to a transmission in an opposite direction.

References in the specification to "one embodiment," "an embodiment," "an example embodiment," and the like indicate that the embodiment described may include a particular feature, structure, or characteristic, but it is not necessary that every embodiment includes the particular feature, structure, or characteristic. Moreover, such phrases are not necessarily referring to the same embodiment. Further, when a particular feature, structure, or characteristic is described in connection with an embodiment, it is submitted that it is within the knowledge of one skilled in the art to affect such feature, structure, or characteristic in connection with other embodiments whether or not explicitly described.

It shall be understood that although the terms "first" and "second" etc. may be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another. For example, a first element could be termed a second element, and similarly, a second element could be termed a first element, without departing from the scope of example embodiments. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed terms.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be liming of example embodiments. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises", "comprising", "has", "having", "includes" and/or "including", when used herein, specify the presence of stated features, elements, and/or components etc., but do not preclude the presence or addition of one or more other features, elements, components and/ or combinations thereof.

In the following description and claims, unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skills in the art to which this disclosure belongs.

The following embodiments of the present disclosure is applicable to both the four-step random access procedure and the two-step random access procedure. Various use cases, services, and features have been introduced in the 5G, including, among others, Mission Critical (MC) communication, Small Data Transmission (SDT), Non-Territorial Network (NTN), and network slicing.

MC Communication

First responders, such as fire-fighters, polices and emergency medical service providers, require fast, reliable and secure communications in various MC situations. During major emergency events, such as nature disasters, there may be a high demand of MC traffic to support the first responders’ rescue operations on site. At the same time, mobile data traffic generated by general public users may increase significantly, e.g., for making emergency calls, sharing information with friends or relatives. If the first responders and the general public users share the same network resources, it is crucial to ensure communication of critical information (e.g., MC services and emergency calls). This brings stringent requirements for 5G access control mechanisms to be able to identify and prioritize access requests from MC service users, to guarantee that they are accepted and properly served even when the network is congested.

SDT

The 5G or NR supports RRCJNACTIVE state, and UEs with infrequent (periodic and/or non-periodic) data transmissions may be generally maintained by the network in the RRCJNACTIVE state. As of NR Release 16, the RRCJNACTIVE state doesn’t support data transmission. Hence, a UE has to resume a connection (i.e. , transition to RRC_CONNECTED state) for any downlink (or Mobile Terminated (MT)) or uplink (or Mobile Originated (MO)) data. Connection setup and subsequent release and transition to the RRCJNACTIVE state occur for each data transmission, however small and infrequent the data packets would be. This results in unnecessary power consumption and signaling overhead.

A work item for support of SDT in NR Release 17 is approved in RAN #86. In RAN2 #111 -e meeting, where it has been agreed that both 2-step random access and 4-step random access will be applied to Random Access Channel (RACH) based uplink small data transmission via Msg3 PUSCH or MsgA PUSCH.

NTN NTNs, e.g., satellite access networks, have been playing a complementary role in the communications ecosystem. Despite the wide deployment of terrestrial mobile networks, there are unserved or underserved areas around the globe due to economic rationales. For example, providing coverage in rural or remote areas has been challenging in many countries because the investment cost may not justify the expected revenue. In contrast, a single communication satellite can cover a large geographic area, and thus it might be economically appealing to use satellite communications to augment terrestrial networks to provide connectivity in rural and remote areas. In urban areas, high-throughput satellites communications systems may help offload traffic in terrestrial networks. Another potential alternative is to use satellites for backhauling, fostering the rollout of 5G services with potentially reduced costs in rural and remote areas. The large satellite coverage can also benefit communication scenarios with airborne and maritime platforms (onboard aircrafts or vessels), while being attractive in certain machine-to-machine and telemetry applications. Additionally, satellites are resilient to natural disasters on earth, making satellite communications key for emergency services in case that the terrestrial network infrastructures are degraded.

Network Slicing

Network slicing is a feature introduced in the 5G to enable service differentiation on a common network infrastructure. Each slice can be a collection of network functionalities or/and resources that are optimized to meet specific requirements for a service type. For instance, a network can configure different slices for eMBB services, Vehicle-to-Everything (V2X) services, MC services, etc. The current NR standard supports only resource separation of user plane data, but does not support full separation of control plane resources, meaning that all network slices share the same RACFI configuration for UEs in the RRCJDLE/INACTIVE states.

To support SDT on Msg3 PUSCFI or MsgA PUSCFI, a network device needs to be able to identify or differentiate an access request related to SDT from other access requests. In order to reduce energy consumption for an SDT service, it is also important to improve the successful rate of its random access attempt to reduce its power-on time. Furthermore, when multiple services (e.g., eMBB services, MC services, TV broadcast services, and SDT services) are supported by satellite communications, it is beneficial for an NTN (e.g., satellite) base station to be able to differentiate different services or UE types at an early stage so that it can optimize its own admission control and/or scheduling decisions, and/or better coordinate with terrestrial network devices to secure communication of critical information.

Currently, regardless of a UE’s service type, or type of used network, or configured network slice, for all UEs in RRCJDLE/INACTIVE states, they use the same 4-step random access configuration for RAR transmission, e.g., the same association between RA-RNTI or MsgB-RNTI and the selected PRACH occasion, the same RAR window, the same CCS for PDCCH scheduling RAR, the same Modulation and Coding Scheme (MCS) table for PDSCH carrying RAR, etc.

Some embodiments of the present disclosure allow configuring RAR repetition, RAR transmission/reception parameters (e.g., RAR window, TB scaling factor, MCS index, MCS table, etc.), or beam selection for terminal devices based on services, network slices, or radio access network types the terminal devices are configured with, such that differentiated RAR transmissions can be provided to meet requirements of different services (service types), network slices, or radio access network types. For instance, by identifying that an access request is transmitted from a UE configured with an MC service, a network slice associated with an MC service, or an NTN, a network device can optimize RAR transmission configuration/scheduling to provide a prioritized, fast and reliable RAR (Msg2 or MsgB) transmission for the UE. As another example, by identifying that an access request is transmitted from a UE configured with an SDT service, the network can optimize RAR transmission configuration/scheduling to shorten activation time for the UE during random access to further reduce its power consumption.

Fig. 2 is a flowchart illustrating a method 200 according to an embodiment of the present disclosure. The method 200 can be performed by a network device, e.g., a gNB.

At 210, an RAR repetition is configured for a terminal device configured with a prioritized service, a network slice associated with the prioritized service, or a prioritized radio access network type. Here, the prioritized service may include an MC service, a multimedia priority service, an SDT service, or any other high- priority service. The prioritized radio access network type may include NTN, which may include e.g., a satellite network, a High-Altitude Platform Station (HAPS) network, or a base station network on an aerial vehicle.

In an example, in the block 210, an indication of a number of RAR repetitions (or Msg2 or MsgB PDSCH repetitions) enabled for terminal devices configured with the prioritized service, the network slice associated with the prioritized service, or the prioritized radio access network type, can be transmitted (or broadcasted) via system information (e.g., SIB1) or PBCH. Here, the number of RAR repetitions, or referred to as “RAR repetition factor”, refers to the number of times the RAR, or Msg2 or MsgB PDSCH, is transmitted repetitively. For example, for the four-step random access procedure, a new RRC parameter, ra-ResponseRepetition, can be added in the field ra- PrioritizationforAccessldentity in the Information Element (IE) RACH- ConfigCommon in the SIB1 , as follows:

The parameter ra-PrioritizationForAI-r16 in the field ra-

PrioritizationforAccessldentity is a 2-bit bitmap, which indicates whether Access Identity (Al) 1 (for UEs configured with multimedia priority services), or Al 2 (for UEs configured with MC services) are enabled. When the field is present in the SIB1 , it indicates that the RAR repetition for UEs configured with Al 1 and/or Al 2 is enabled for the network device. The parameter ra-ResponseRepetition indicates an RAR repetition factor (which can be e.g., 2 or 4) to be applied for UEs configured with Al 1 and/or Al 2. For further details of the IE RACH-ConfigCommon, reference can be made to 3GPP TS 38.331, V16.0.0, which is incorporated herein by reference in its entirety. Similarly, for the two-step random access procedure, a new RRC parameter, ra- ResponseRepetition, can be added in the field ra- PrioritizationForAccessldentityTwoStep in the IE RACH- ConfigCommonTwoStepRA to indicate the RAR repetition factor, as follows:

For further details of the IE RACH-ConfigCommonTwoStepRA, reference can be made to 3GPP TS 38.331 , V16.0.0. Alternatively, in the block 210, an indication of the RAR repetition factor can be transmitted to the terminal device via dedicated RRC signaling, e.g., in a successful connection before the current random access procedure.

In an example, the network device can receive, from the terminal device, a random access preamble (in Msg1 or MsgA), and determine that the terminal device is configured with the prioritized service, the network slice associated with the prioritized service, or the prioritized radio access network type. For example, for a four-step random access procedure, a priority level of the service the terminal device is configured with, a priority level of the service associated with the network slice the terminal device is configured with, or a network priority level of the radio access network type the terminal device is configured with can be determined based on the random access preamble or a PRACH occasion in which the random access preamble is transmitted. For a two-step random access procedure, a priority level of the service the terminal device is configured with, a priority level of the service associated with the network slice the terminal device is configured with, or a network priority level of the radio access network type the terminal device is configured with can be determined based on the random access preamble, a MsgA PUSCFI or a PRACFI occasion in which the random access preamble is transmitted. In response to determining that the terminal device is configured with the prioritized service, the network slice associated with the prioritized service, or the prioritized radio access network type, the network device can transmit, to the terminal device, an indication of a number of RAR repetitions in DCI. For example, a 2-bit field Repetition Factor can be added to DCI Format 1_0 with CRC scrambled by RA-RNTI or msgB-RNTI to signal an RAR repetition factor of 0 (no repetition), 2, 4, or 8 for Msg2 or MsgB PDSCFI, as follows: - Reserved bits - 12 bits for the DCI format 1 0 with CRC scrambled by msgB- RNTI or for operation in a cell with shared spectrum channel access; otherwise 14 bits

As an alternative, the above field Time domain resource assignment can be used for indicating a row of the time domain resource allocation list (table) that includes the RAR repetition factor.

For further details of the DCI Format 1_0, reference can be made to 3GPP TS 38.212, V16.1.0, which is incorporated herein by reference in its entirety.

The above RRC parameter (e.g., ra-ResponseRepetition) in the SIB1 and the field (e.g., RepetitionFactor or Time domain resource assignment) in the DCI can be used in combination for configuring the RAR repetition factor. For example, the RAR repetition factor indicated in the DCI can dynamically override the RAR repetition factor indicated in the SIB1.

In an example, e.g., after the block 210, the network device can transmit, to the terminal device, an RAR (in Msg2 or MsgB) for the number of RAR repetitions.

Fig. 3 is a flowchart illustrating a method 300 according to another embodiment of the present disclosure. The method 300 can be performed by a network device, e.g., a gNB.

At block 310, a parameter for RAR transmission or reception is configured for a terminal device configured with a service having a priority level, a network slice associated with the service, or a radio access network type having a network priority level. Flere, the service may include an MC service, a multimedia priority service, or an SDT service. The radio access network type may include NTN, which may include e.g., a satellite network, a FIAPS network, or a base station network on an aerial vehicle.

In particular, in an example, the parameter may include a first RAR window which is different from (e.g., shorter than) a second RAR window for RAR reception for another terminal device configured with another service having another priority level lower than the priority level, another network slice associated with the other service, or another radio access network type having another network priority level lower than the network priority level. For example, the first RAR window can be transmitted to the terminal device via RRC signaling (e.g., SIB1). The shorter RAR window can reduce the access latency for the terminal device configured with the higher-priority service, network slice associated with the higher-priority service, or higher-priority radio access network type.

In another example, the parameter may include a first Transport Block (TB) scaling factor which is smaller than a second TB scaling factor for RAR transmission for another terminal device configured with another service having another priority level lower than the priority level, another network slice associated with the other service, or another radio access network type having another network priority level lower than the network priority level, and/or a first Modulation and Coding Scheme (MCS) index which is smaller than a second MCS index for RAR transmission for another terminal device configured with another service having another priority level lower than the priority level, another network slice associated with the other service, or another radio access network type having another network priority level lower than the network priority level. For example, the first TB scaling factor and/or the first MCS index can be transmitted to the terminal device via DCI. The smaller TB scaling factor or MCS index can reduce the channel coding rate and thereby improving the reliability of the PDSCFI transmission for the terminal device configured with the higher-priority service, network slice associated with the higher-priority service, or higher-priority radio access network type.

In another example, the parameter may include an indication of a first MCS table which has lower spectral efficiency than a second MCS table for RAR transmission for another terminal device configured with another service having another priority level lower than the priority level, another network slice associated with the other service, or another radio access network type having another network priority level lower than the network priority level. This can also improve the reliability of the PDSCFI transmission for the terminal device configured with the higher-priority service, network slice associated with the higher-priority service, or higher-priority radio access network type. For example, for PDSCH transmission in NR, three MCS index tables have been given in the 3GPP TS 38.214, V16.0.0: Table 5.1 .3.1-1 , Table 5.1 .3.1-2, and Table 5.1.3.1-3, reproduced below as Table 1 , Table 2, and Table 3, respectively.

Table 1 : MCS index table 1 for PDSCH

Table 2: MCS index table 2 for PDSCH

Table 3: MCS index table 3 for PDSCH

Table 1 is for normal spectrum efficiency with a maximum modulation order of 6, i.e. , 64 Quadrature Amplitude Modulation (QAM). Table 2 is for normal spectrum efficiency with a maximum modulation order of 8, i.e., 256QAM. Table 3 is for low spectrum efficiency with a maximum modulation order of 6, i.e., 64QAM. According to TS 38.214, V16.0.0, for Msg2 or MsgB PDSCH, Table 1 is used and the modulation order is restricted to be always smaller than or equal to 2. In an example, Table 3 can be used for Msg2 or MsgB PDSCH for the terminal device configured with the higher-priority service, network slice associated with the higher-priority service, or higher-priority radio access network type, so as to improve the reliability of the PDSCH transmission. In another example, the parameter may indicate that an earliest usable downlink symbol or a p/2 Binary Phase Shift Keying, BPSK, modulation is to be used for RAR transmission, so as to improve the reliability of the RAR transmission for the terminal device configured with the higher-priority service, network slice associated with the higher-priority service, or higher-priority radio access network type.

In an example, the network device can receive from the terminal device a random access preamble, and determine that the terminal device is configured with the service having the priority level, the network slice associated with the service, or the radio access network type having the network priority level. Here, the priority level and/or the network priority level can be determined based on the random access preamble or a PRACH occasion in which the random access preamble is transmitted, or a MsgA PUSCH (for two-step random access), as described above. The network device can transmit an RAR to the terminal device in accordance with the parameter.

Fig. 4 is a flowchart illustrating a method 400 according to yet another embodiment of the present disclosure. The method 400 can be performed by a network device, e.g., a gNB.

At block 410, a first random access preamble (e.g., in Msg1 or MsgA) is received from a first terminal device configured with a first service having a first priority level, a first network slice associated with the first service, or a first radio access network type having a first network priority level. The first random access preamble is mapped to a first SSB. Here, the first service may include an MC service, a multimedia priority service, or an SDT serivce. The first radio access network type may include NTN, which may include e.g., a satellite network, a HAPS network, or a base station network on an aerial vehicle.

At block 420, a first RAR (in Msg2 or MsgB) is transmitted to the first terminal device via a first SSB beam corresponding to the first SSB, or an SSB beam closer to the first SSB beam than a second SSB beam via which a second RAR (in Msg2 or MsgB) for a second terminal device is transmitted. The second terminal device is configured with a second service having a second priority level lower than the first priority level, a second network slice associated with the second service, or a second radio access network type having a second network priority level lower than the first network priority level, and has transmitted a second random access preamble mapped to the first SSB. For example, when the network device receives, from multiple UEs, multiple preambles mapped to one SSB, it can use the SSB beam corresponding to the one SSB for transmitting RARs to the UEs with high-priority services (or network slices associated with high-priority services, or high-priority radio access network types), and use other (e.g., neighboring) SSB beams for transmitting RARs to the UEs with low-priority services (or network slices associated with low-priority services, or low-priority radio access network types), so as to reduce interference between the UEs with the high-priority services (or network slices associated with high-priority services, or high-priority radio access network types) and the UEs with the low-priority services (or network slices associated with low-priority services, or low-priority radio access network types). In general, the SSB beams used for RAR transmission can be determined in such a manner that a UE with a higher-priority service (or a network slice associated with a high-priority service, or a high-priority radio access network type) is to use an SSB beam closer to the one SSB than a UE with a lower-priority service (or a network slice associated with a low-priority service, or a low-priority radio access network type). At least the UE with the highest-priority service (or the network slice associated with the highest-priority service, or the highest-priority radio access network type) can use the one SSB beam.

Fig. 5 is a flowchart illustrating a method 500 according to still another embodiment of the present disclosure. The method 500 can be performed by a network device, e.g., a gNB.

At block 510, a plurality of random access preambles are received from a plurality of terminal devices, respectively, in one random access occasion.

At block 520, one or more RARs are transmitted to one or more of the plurality of terminal devices based on priority levels of respective services or network priority levels of respective radio access network types. The plurality of terminal devices are configured with the respective services, network slices associated with the respective services, or the respective radio access network types.

In an example, in the block 520, an RAR message (e.g., Msg2 or MsgB) can be transmitted. The RAR message can contain one or more RARs for one or more of the plurality of terminal devices that are configured with services each having a priority level higher than or equal to a priority level threshold, network slices each associated with a service having a priority level higher than or equal to the priority level threshold, or radio access network types each having a network priority level higher than or equal to a network priority level threshold. In addition, one or more further RAR messages can be transmitted. Each of the one or more further RAR messages can contain one or more RARs for one or more of the plurality of terminal devices that are configured with services having one of the priority levels that is lower than the priority level threshold or network slices associated with services having one of the priority levels that is lower than the priority level threshold, in a descending order of the priority levels, until a maximum number of admissible terminal devices is reached. Alternatively, each of the one or more further RAR messages can contain one or more RARs for one or more of the plurality of terminal devices that are configured with radio access network types having one of the network priority levels that is lower than the network priority level threshold, in a descending order of the network priority levels, until a maximum number of admissible terminal devices is reached.

In an example, in the block 520, an RAR message (e.g., Msg2 or MsgB) can be transmitted. The RAR message can be obtained by adding RARs for the plurality of terminal devices, in a descending order of the priority levels or the network priority levels, until a maximum number of allowable RARs in one RAR message or a maximum number of admissible terminal devices is reached.

In an example, the plurality of random access preambles may be mapped to different SSBs. In the block 520, the one or more RARs can be transmitted to the one or more terminal devices via one SSB beam corresponding to an SSB to which the random access preamble from one of the plurality of terminal devices that is configured with a service having a highest priority level among the priority levels, a network slice associated with the service having the highest priority level, or a radio access network type having a highest priority level among the network priority levels is mapped, or a beam quasi-co-located with the one SSB beam. DCI for scheduling the one or more RARs can be transmitted to the one or more terminal devices via the one SSB beam or a beam quasi-co-located with the one SSB beam. Fig. 6 is a flowchart illustrating a method 600 according to an embodiment of the present disclosure. The method 600 can be performed by a terminal device, e.g., a UE. The method 600 may correspond to the method 200 as described above in connection with Fig. 2.

At block 610, a configuration of an RAR repetition for a prioritized service, a network slice associated with the prioritized service, or a prioritized radio access network type is received from a network device (e.g., a gNB). Flere, the prioritized service may include an MC service, a multimedia priority service, or an SDT service. The prioritized radio access network type may include NTN, which may include e.g., a satellite network, a FIAPS network, or a base station network on an aerial vehicle.

In an example, in the block 610, the configuration can be received via system information (e.g., SIB1) or PBCFI, and can include an indication of a number of RAR repetitions enabled for terminal devices configured with the prioritized service, the network slice associated with the prioritized service, or the prioritized radio access network type. Flere, the indication may be the RRC parameter ra- ResponseRepetition as described above in connection with the method 200.

In another example, in the block 610, the configuration can be received via dedicated RRC signaling and can include an indication of a number of RAR repetitions.

In an example, a random access preamble (e.g., in Msg1 or MsgA) can be transmitted to the network device. The random access preamble, a PRACFI occasion in which the random access preamble is transmitted, or a MsgA PUSCFI can enable the network device to determine that the terminal device is configured with the prioritized service, the network slice associated with the prioritized service, or the prioritized radio access network type. In the block 610, the configuration can be received via DCI, and can include an indication of a number of RAR repetitions. Flere, the indication may be the field RepetitionFactor or Time domain resource assignment as described above in connection with the method 200. In an example, the terminal device can receive, from the network device, an RAR in at least one of the number of RAR repetitions.

Fig. 7 is a flowchart illustrating a method 700 according to another embodiment of the present disclosure. The method 700 can be performed by a terminal device, e.g., a UE. The method 700 may correspond to the method 300 as described above in connection with Fig. 3.

At block 710, a parameter for RAR transmission or reception for a service having a priority level, a network slice associated with the service, or a radio access network type having a network priority level is received from a network device. Flere, the service may include an MC service, a multimedia priority service, or an SDT service. The radio access network type may include NTN, which may include e.g., a satellite network, a FIAPS network, or a base station network on an aerial vehicle.

In an example, the parameter may include a first RAR window which is different from (e.g., shorter than) a second RAR window for RAR reception for another service having another priority level lower than the priority level, another network slice associated with the other service, or another radio access network type having another network priority level lower than the network priority level.

In an example, the parameter may include a first TB scaling factor which is smaller than a second TB scaling factor for RAR transmission for another service having another priority level lower than the priority level, another network slice associated with the other service, or another radio access network type having another network priority level lower than the network priority level, and/or a first MCS index which is smaller than a second MCS index for RAR transmission for another service having another priority level lower than the priority level, another network slice associated with the other service, or another radio access network type having another network priority level lower than the network priority level.

In an example, the parameter may include an indication of a first MCS table (e.g., the above Table 3) which has lower spectral efficiency than a second MCS table for RAR transmission for another service having another priority level lower than the priority level, another network slice associated with the other service, or another radio access network type having another network priority level lower than the network priority level.

In an example, the parameter may indicate that an earliest usable downlink symbol or a p/2 BPSK modulation is to be used for RAR transmission.

In an example, the terminal device can receive, from the network device, an RAR in accordance with the parameter.

Fig. 8 is a flowchart illustrating a method 800 according to another embodiment of the present disclosure. The method 800 can be performed by a terminal device, e.g., a UE.

At block 810, a random access preamble (e.g., in Msg1 or MsgA) is transmitted to a network device (e.g., a gNB).

At block 820, DCI from the network device is monitored for scheduling an RAR message (e.g., Msg2 or MsgB).

At block 830, it is determined that the RAR message does not contain an RAR for the terminal device.

At block 840, further DCI from the network device is monitored within an RAR window for scheduling a further RAR message.

In an example, the DCI and the further DCI are addressed to an RNTI (e.g., RA- RNTI or MsgB-RNTI) associated with a random access occasion in which the random access preamble is transmitted.

In NR Release 15, the UE behavior for Msg2 or MsgB reception is defined such that after a successful decoding of a single PDCCH with its corresponding RA- RNTI or MsgB-RNTI, a UE will stop monitoring other PDCCH candidates within the RAR window, regardless whether it can find a RAPID in the RAR(s) of the Msg2 or MsgB that matches its selected preamble. In other words, the UE will perform at most one single Msg2 or MsgB reception within the RAR window, regardless whether or not there are more Msg2 or MsgB PDSCH transmissions associated with the same RA-RNTI from the network device.

According to the method 800, a new UE behavior is defined for Msg2 or MsgB PDSCH reception. If a UE successfully decodes a PDCCH with its corresponding RA-RNTI or MsgB-RNTI but fails to find a RAPID in the RAR(s) of the Msg2 or MsgB that matches its selected preamble, it can continue to monitor further PDCCH candidates with its corresponding RA-RNTI or MsgB-RNTI within the RAR window, until it identifies a RAPID in the RAR(s) that matches its selected preamble, or it reaches a maximum number of PDCCH decoding for Msg2 or MsgB reception. Accordingly, the network device can transmit multiple Msg2 or MsgB PDSCHs each formed by multiplexing RARs for UEs configured with services having one priority level, network slices associated with services having one priority level, or radio access network types having one network priority level. The network device can apply different configurations for the multiple Msg2 or MsgB PDSCH transmissions according to the respective priority levels or network priority levels.

Correspondingly to the methods 200, 300, 400 and 500 as described above, a network device is provided. Fig. 9 is a block diagram of a network device 900 according to an embodiment of the present disclosure.

The network device 900 can be configured to perform the method 200 as described above in connection with Fig. 2. As shown in Fig. 9, the network device includes a unit 910 configured to configure an RAR repetition for a terminal device configured with a prioritized service, a network slice associated with the prioritized service, or a prioritized radio access network type.

In an embodiment, the unit 910 can be configured to transmit an indication of a number of RAR repetitions enabled for terminal devices configured with the prioritized service, the network slice associated with the prioritized service, or the prioritized radio access network type via system information or PBCH.

In an embodiment, the unit 910 can be configured to transmit, to the terminal device, an indication of a number of RAR repetitions via dedicated RRC signaling. In an embodiment, the network device 900 may further include a unit 920 configured to receive, from the terminal device, a random access preamble; and a unit 930 configured to determine that the terminal device is configured with the prioritized service, the network slice associated with the prioritized service, or the prioritized radio access network type. The unit 910 can be configured to, in response to the determining: transmit, to the terminal device, an indication of a number of RAR repetitions in DCI.

In an embodiment, the network device 900 may further include a unit 940 configured to transmit, to the terminal device, an RAR for the number of RAR repetitions.

In an embodiment, the prioritized service may include an MC service, a multimedia priority service, or an SDT service. The prioritized radio access network type may include NTN, which may include e.g., a satellite network, a HAPS network, or a base station network on an aerial vehicle.

Alternatively, the network device 900 can be configured to perform the method 300 as described above in connection with Fig. 3. As shown in Fig. 9, the network device 900 includes a unit 910 configured to configure a parameter for RAR transmission or reception for a terminal device configured with a service having a priority level, a network slice associated with the service, or a radio access network type having a network priority level.

In an embodiment, the parameter may include a first RAR window which is different from a second RAR window for RAR reception for another terminal device configured with another service having another priority level lower than the priority level, another network slice associated with the other service, or another radio access network type having another network priority level lower than the network priority level.

In an embodiment, the first RAR window may be shorter than the second RAR window.

In an embodiment, the network device 900 may further include a unit 920 configured to receive, from the terminal device, a random access preamble; determining that the terminal device is configured with the service having the priority level, the network slice associated with the service, or the radio access network type having the network priority level; and a unit 930 configured to transmit, to the terminal device, an RAR in accordance with the parameter.

In an embodiment, the service may include an MC service, a multimedia priority service, or an SDT service. The radio access network type may include NTN, which may include e.g., a satellite network, a HAPS network, or a base station network on an aerial vehicle.

Alternatively, the network device 900 can be configured to perform the method 400 as described above in connection with Fig. 4. As shown in Fig. 9, the network device 900 includes a unit 910 configured to receive, from a first terminal device configured with a first service having a first priority level, a first network slice associated with the first service, or a first radio access network type having a first network priority level, a first random access preamble mapped to a first SSB. The network device 900 further includes a unit 920 configured to transmit, to the first terminal device, a first RAR via a first SSB beam corresponding to the first SSB, or an SSB beam closer to the first SSB beam than a second SSB beam via which a second RAR for a second terminal device is transmitted, the second terminal device being configured with a second service having a second priority level lower than the first priority level, a second network slice associated with the second service, or a second radio access network type having a second network priority level lower than the first network priority level and having transmitted a second random access preamble mapped to the first SSB.

In an embodiment, the first service may include an MC service, a multimedia priority service, or an SDT service. The first radio access network type may include NTN, which may include e.g., a satellite network, a HAPS network, or a base station network on an aerial vehicle.

Alternatively, the network device 900 can be configured to perform the method 500 as described above in connection with Fig. 5. As shown in Fig. 9, the network device 900 includes a unit 910 configured to receive a plurality of random access preambles from a plurality of terminal devices, respectively, in one random access occasion. The network device 900 includes a unit 920 configured to transmit one or more RARs to one or more of the plurality of terminal devices based on priority levels of respective services or network priority levels of respective radio access network types, the plurality of terminal devices being configured with the respective services, network slices associated with the respective services, or the respective radio access network types.

In an embodiment, the unit 920 can be configured to transmit an RAR message containing one or more RARs for one or more of the plurality of terminal devices that are configured with services each having a priority level higher than or equal to a priority level threshold, network slices each associated with a service having a priority level higher than or equal to the priority level threshold, or radio access network types each having a network priority level higher than or equal to a network priority level threshold. In an embodiment, the unit 920 can be further configured to transmit one or more further RAR messages each containing one or more RARs for one or more of the plurality of terminal devices that are configured with services having one of the priority levels that is lower than the priority level threshold or network slices associated with services having one of the priority levels that is lower than the priority level threshold, in a descending order of the priority levels, until a maximum number of admissible terminal devices is reached, or transmit one or more further RAR messages each containing one or more RARs for one or more of the plurality of terminal devices that are configured with radio access network types having one of the network priority levels that is lower than the network priority level threshold, in a descending order of the network priority levels, until a maximum number of admissible terminal devices is reached.

In an embodiment, the unit 920 can be configured to transmit an RAR message obtained by adding RARs for the plurality of terminal devices, in a descending order of the priority levels or the network priority levels, until a maximum number of allowable RARs in one RAR message or a maximum number of admissible terminal devices is reached.

In an embodiment, the plurality of random access preambles may be mapped to different SSBs. The unit 920 can be configured to transmit the one or more RARs to the one or more terminal devices via one SSB beam corresponding to an SSB to which the random access preamble from one of the plurality of terminal devices that is configured with a service having a highest priority level among the priority levels, a network slice associated with the service having the highest priority level, or a radio access network type having a highest priority level among the network priority levels is mapped, or a beam quasi-co-located with the one SSB beam.

In an embodiment, the network device 900 may further include a unit 930 configured to transmit DCI for scheduling the one or more RARs to the one or more terminal devices via the one SSB beam or a beam quasi-co-located with the one SSB beam.

The above unit 910 and optionally the units 920, 930, and 940 can be implemented as a pure hardware solution or as a combination of software and hardware, e.g., by one or more of: a processor or a micro-processor and adequate software and memory for storing of the software, a Programmable Logic Device (PLD) or other electronic component(s) or processing circuitry configured to perform the actions described above, and illustrated, e.g., in any of Figs. 2, 3, 4, and 5.

Fig. 10 is a block diagram of a network device 1000 according to another embodiment of the present disclosure.

The network device 1000 includes a transceiver 1010, a processor 1020 and a memory 1030.

The memory 1030 can contain instructions executable by the processor 1020 whereby the network device 1000 is operative to perform the actions, e.g., of the procedure described earlier in conjunction with Fig. 2. Particularly, the memory 1030 can contain instructions executable by the processor 1020 whereby the network device 1000 is operative to: configure an RAR repetition for a terminal device configured with a prioritized service, a network slice associated with the prioritized service, or a prioritized radio access network type.

In an embodiment, the operation of configuring may include: transmitting an indication of a number of RAR repetitions enabled for terminal devices configured with the prioritized service, the network slice associated with the prioritized service, or the prioritized radio access network type via system information or PBCH.

In an embodiment, the memory 1030 may further contain instructions executable by the processor 1020 whereby the network device 1000 is operative to: receive, from the terminal device, a random access preamble; and determine that the terminal device is configured with the prioritized service, the network slice associated with the prioritized service, or the prioritized radio access network type. The operation of configuring may include, in response to the determining: transmitting, to the terminal device, an indication of a number of RAR repetitions in DCI.

In an embodiment, the memory 1030 may further contain instructions executable by the processor 1020 whereby the network device 1000 is operative to: transmit, to the terminal device, an RAR for the number of RAR repetitions.

Alternatively, the memory 1030 can contain instructions executable by the processor 1020 whereby the network device 1000 is operative to perform the actions, e.g., of the procedure described earlier in conjunction with Fig. 3. Particularly, the memory 1030 can contain instructions executable by the processor 1020 whereby the network device 1000 is operative to: configure a parameter for RAR transmission or reception for a terminal device configured with a service having a priority level, a network slice associated with the service, or a radio access network type having a network priority level.

In an embodiment, the memory 1030 may further contain instructions executable by the processor 1020 whereby the network device 1000 is operative to: receive, from the terminal device, a random access preamble; determine that the terminal device is configured with the service having the priority level, the network slice associated with the service, or the radio access network type having the network priority level; and transmit, to the terminal device, an RAR in accordance with the parameter.

Alternatively, the memory 1030 can contain instructions executable by the processor 1020 whereby the network device 1000 is operative to perform the actions, e.g., of the procedure described earlier in conjunction with Fig. 4. Particularly, the memory 1030 can contain instructions executable by the processor 1020 whereby the network device 1000 is operative to: receive, from a first terminal device configured with a first service having a first priority level, a first network slice associated with the first service, or a first radio access network type having a first network priority level, a first random access preamble mapped to a first SSB; and transmitting, to the first terminal device, a first RAR via a first SSB beam corresponding to the first SSB, or an SSB beam closer to the first SSB beam than a second SSB beam via which a second RAR for a second terminal device is transmitted, the second terminal device being configured with a second service having a second priority level lower than the first priority level, a second network slice associated with the second service, or a second radio access network type having a second network priority level lower than the first network priority level and having transmitted a second random access preamble mapped to the first SSB.

Alternatively, the memory 1030 can contain instructions executable by the processor 1020 whereby the network device 1000 is operative to perform the actions, e.g., of the procedure described earlier in conjunction with Fig. 5. Particularly, the memory 1030 can contain instructions executable by the processor 1020 whereby the network device 1000 is operative to: receive a plurality of random access preambles from a plurality of terminal devices, respectively, in one random access occasion; and transmit one or more RARs to one or more of the plurality of terminal devices based on priority levels of respective services or network priority levels of respective radio access network types, the plurality of terminal devices being configured with the respective services, network slices associated with the respective services, or the respective radio access network types.

In an embodiment, the memory 1030 may further contain instructions executable by the processor 1020 whereby the network device 1000 is operative to: transmit DCI for scheduling the one or more RARs to the one or more terminal devices via the one SSB beam or a beam quasi-co-located with the one SSB beam. Correspondingly to the methods 600, 700 and 800 as described above, a terminal device is provided. Fig. 11 is a block diagram of a terminal device 1100 according to an embodiment of the present disclosure.

The terminal device 1100 can be configured to perform the method 600 as described above in connection with Fig. 6. As shown in Fig. 11 , the terminal device 1100 includes a unit 1110 configured to receive, from a network device, a configuration of an RAR repetition for a prioritized service, a network slice associated with the prioritized service, or a prioritized radio access network type.

In an embodiment, the configuration may be received via system information or PBCFI, and may include an indication of a number of RAR repetitions enabled for terminal devices configured with the prioritized service, the network slice associated with the prioritized service, or the prioritized radio access network type.

In an embodiment, the terminal device 1100 may further include a unit 1120 configured to transmit, to the network device, a random access preamble. The configuration may be received via DCI and may include an indication of a number of RAR repetitions.

In an embodiment, the terminal device 1100 may further include a unit 1130 configured to receive, from the network device, an RAR in at least one of the number of RAR repetitions.

In an embodiment, the prioritized service may include an MC service, a multimedia priority service, or an SDT service. The prioritized radio access network type may include NTN, which may include e.g., a satellite network, a FIAPS network, or a base station network on an aerial vehicle.

Alternatively, the terminal device 1100 can be configured to perform the method 700 as described above in connection with Fig. 7. As shown in Fig. 11 , the terminal device 1100 includes a unit 1110 configured to receive, from a network device, a parameter for RAR transmission or reception for a service having a priority level, a network slice associated with the service, or a radio access network type having a network priority level.

In an embodiment, the parameter may include a first RAR window which is different from a second RAR window for RAR reception for another service having another priority level lower than the priority level, another network slice associated with the other service, or another radio access network type having another network priority level lower than the network priority level.

In an embodiment, the parameter may indicate that an earliest usable downlink symbol or a p/2 BPSK modulation is to be used for RAR transmission. In an embodiment, the terminal device 1100 may further include a unit 1120 configured to receive, from the network device, an RAR in accordance with the parameter.

Alternatively, the terminal device 1100 can be configured to perform the method 800 as described above in connection with Fig. 8. As shown in Fig. 11 , the terminal device 1100 includes a unit 1110 configured to transmit, to a network device, a random access preamble. The terminal device 1100 further includes a unit 1120 configured to monitor DCI from the network device for scheduling an RAR message. The terminal device 1100 further includes a unit 1130 configured to determine that the RAR message does not contain an RAR for the terminal device. The unit 1120 is further configured to monitor, within an RAR window, further DCI from the network device for scheduling a further RAR message.

The above unit 1110 and optionally the units 1120-1130 can be implemented as a pure hardware solution or as a combination of software and hardware, e.g., by one or more of: a processor or a micro-processor and adequate software and memory for storing of the software, a Programmable Logic Device (PLD) or other electronic component(s) or processing circuitry configured to perform the actions described above, and illustrated, e.g., in any of Figs. 6, 7 and 8.

Fig. 12 is a block diagram of a terminal device 1200 according to another embodiment of the present disclosure.

The terminal device 1200 includes a transceiver 1210, a processor 1220 and a memory 1230. The memory 1230 can contain instructions executable by the processor 1220 whereby the terminal device 1200 is operative to perform the actions, e.g., of the procedure described earlier in conjunction with Fig. 6. Particularly, the memory 1230 can contain instructions executable by the processor 1220 whereby the terminal device 1200 is operative to: receive, from a network device, a configuration of an RAR repetition for a prioritized service, a network slice associated with the prioritized service, or a prioritized radio access network type.

In an embodiment, the configuration may be received via system information or PBCH, and may include an indication of a number of RAR repetitions enabled for terminal devices configured with the prioritized service, the network slice associated with the prioritized service, or the prioritized radio access network type.

In an embodiment, the memory 1230 may further contain instructions executable by the processor 1220 whereby the terminal device 1200 is operative to: transmit, to the network device, a random access preamble. The configuration may be received via DCI and may include an indication of a number of RAR repetitions.

In an embodiment, the memory 1230 may further contain instructions executable by the processor 1220 whereby the terminal device 1200 is operative to: receive, from the network device, an RAR in at least one of the number of RAR repetitions.

Alternatively, the memory 1230 can contain instructions executable by the processor 1220 whereby the terminal device 1200 is operative to perform the actions, e.g., of the procedure described earlier in conjunction with Fig. 7. Particularly, the memory 1230 can contain instructions executable by the processor 1220 whereby the terminal device 1200 is operative to: receive, from a network device, a parameter for RAR transmission or reception for a service having a priority level, a network slice associated with the service, or a radio access network type having a network priority level.

In an embodiment, the parameter may indicate that an earliest usable downlink symbol or a p/2 BPSK modulation is to be used for RAR transmission. In an embodiment, the memory 1230 may further contain instructions executable by the processor 1220 whereby the terminal device 1200 is operative to: receive, from the network device, an RAR in accordance with the parameter.

Alternatively, the memory 1230 can contain instructions executable by the processor 1220 whereby the terminal device 1200 is operative to perform the actions, e.g., of the procedure described earlier in conjunction with Fig. 8. Particularly, the memory 1230 can contain instructions executable by the processor 1220 whereby the terminal device 1200 is operative to: transmit, to a network device, a random access preamble; monitor DCI from the network device for scheduling an RAR message; determine that the RAR message does not contain an RAR for the terminal device; and monitor, within an RAR window, further DCI from the network device for scheduling a further RAR message.

The present disclosure also provides at least one computer program product in the form of a non-volatile or volatile memory, e.g., a non-transitory computer readable storage medium, an Electrically Erasable Programmable Read-Only Memory (EEPROM), a flash memory and a hard drive. The computer program product includes a computer program. The computer program includes: code/computer readable instructions, which when executed by the processor 1020 causes the network device 1000 to perform the actions, e.g., of the procedure described earlier in conjunction with any of Figs. 2-5; or code/computer readable instructions, which when executed by the processor 1220 causes the terminal device 1200 to perform the actions, e.g., of the procedure described earlier in conjunction with any of Figs. 6-8. The computer program product may be configured as a computer program code structured in computer program modules. The computer program modules could essentially perform the actions of the flow illustrated in any of Figs. 2-8.

The processor may be a single CPU (Central Processing Unit), but could also comprise two or more processing units. For example, the processor may include general purpose microprocessors; instruction set processors and/or related chips sets and/or special purpose microprocessors such as Application Specific Integrated Circuits (ASICs). The processor may also comprise board memory for caching purposes. The computer program may be carried by a computer program product connected to the processor. The computer program product may comprise a non-transitory computer readable storage medium on which the computer program is stored. For example, the computer program product may be a flash memory, a Random Access Memory (RAM), a Read-Only Memory (ROM), or an EEPROM, and the computer program modules described above could in alternative embodiments be distributed on different computer program products in the form of memories.

With reference to Fig. 13, in accordance with an embodiment, a communication system includes a telecommunication network 1310, such as a 3GPP-type cellular network, which comprises an access network 1311 , such as a radio access network, and a core network 1314. The access network 1311 comprises a plurality of base stations 1312a, 1312b, 1312c, such as NBs, eNBs, gNBs or other types of wireless access points, each defining a corresponding coverage area 1312a, 1312b, 1312c. Each base station 1312a, 1312b, 1312c is connectable to the core network 1314 over a wired or wireless connection 1315. A first UE 1391 located in a coverage area 1312c is configured to wirelessly connect to, or be paged by, the corresponding base station 1312c. A second UE 1392 in a coverage area 1312a is wirelessly connectable to the corresponding base station 1312a. While a plurality of UEs 1391, 1392 are illustrated in this example, the disclosed embodiments are equally applicable to a situation where a sole UE is in the coverage area or where a sole UE is connecting to the corresponding base station 1312.

The telecommunication network 1310 is itself connected to a host computer 1330, which may be embodied in the hardware and/or software of a standalone server, a cloud-implemented server, a distributed server or as processing resources in a server farm. The host computer 1330 may be under the ownership or control of a service provider, or may be operated by the service provider or on behalf of the service provider. Connections 1321 and 1322 between the telecommunication network 1310 and the host computer 1330 may extend directly from the core network 1314 to the host computer 1330 or may go via an optional intermediate network 1320. An intermediate network 1320 may be one of, or a combination of more than one of, a public, private or hosted network; the intermediate network 1320, if any, may be a backbone network or the Internet; in particular, the intermediate network 1320 may comprise two or more sub-networks (not shown).

The communication system of Fig. 13 as a whole enables connectivity between the connected UEs 1391, 1392 and the host computer 1330. The connectivity may be described as an over-the-top (OTT) connection 1350. The host computer 1330 and the connected UEs 1391 , 1392 are configured to communicate data and/or signaling via the OTT connection 1350, using the access network 1311, the core network 1314, any intermediate network 1320 and possible further infrastructure (not shown) as intermediaries. The OTT connection 1350 may be transparent in the sense that the participating communication devices through which the OTT connection 1350 passes are unaware of routing of uplink and downlink communications. For example, the base station 1312 may not or need not be informed about the past routing of an incoming downlink communication with data originating from the host computer 1330 to be forwarded (e.g., handed over) to a connected UE 1391. Similarly, the base station 1312 need not be aware of the future routing of an outgoing uplink communication originating from the UE 1391 towards the host computer 1330.

Example implementations, in accordance with an embodiment, of the UE, base station and host computer discussed in the preceding paragraphs will now be described with reference to Fig. 14. In a communication system 1400, a host computer 1410 comprises hardware 1415 including a communication interface 1416 configured to set up and maintain a wired or wireless connection with an interface of a different communication device of the communication system 1400. The host computer 1410 further comprises a processing circuitry 1418, which may have storage and/or processing capabilities. In particular, the processing circuitry 1418 may comprise one or more programmable processors, application- specific integrated circuits, field programmable gate arrays or combinations of these (not shown) adapted to execute instructions. The host computer 1410 further comprises software 1411 , which is stored in or accessible by the host computer 1410 and executable by the processing circuitry 1418. The software 1411 includes a host application 1412. The host application 1412 may be operable to provide a service to a remote user, such as UE 1430 connecting via an OTT connection 1450 terminating at the UE 1430 and the host computer 1410. In providing the service to the remote user, the host application 1412 may provide user data which is transmitted using the OTT connection 1450.

The communication system 1400 further includes a base station 1420 provided in a telecommunication system and comprising hardware 1425 enabling it to communicate with the host computer 1410 and with the UE 1430. The hardware 1425 may include a communication interface 1426 for setting up and maintaining a wired or wireless connection with an interface of a different communication device of the communication system 1400, as well as a radio interface 1427 for setting up and maintaining at least a wireless connection 1470 with the UE 1430 located in a coverage area (not shown in Fig. 14) served by the base station 1420. The communication interface 1426 may be configured to facilitate a connection 1460 to the host computer 1410. The connection 1460 may be direct or it may pass through a core network (not shown in Fig. 14) of the telecommunication system and/or through one or more intermediate networks outside the telecommunication system. In the embodiment shown, the hardware 1425 of the base station 1420 further includes a processing circuitry 1428, which may comprise one or more programmable processors, application-specific integrated circuits, field programmable gate arrays or combinations of these (not shown) adapted to execute instructions. The base station 1420 further has software 1421 stored internally or accessible via an external connection.

The communication system 1400 further includes the UE 1430 already referred to. Its hardware 1435 may include a radio interface 1437 configured to set up and maintain a wireless connection 1470 with a base station serving a coverage area in which the UE 1430 is currently located. The hardware 1435 of the UE 1430 further includes a processing circuitry 1438, which may comprise one or more programmable processors, application-specific integrated circuits, field programmable gate arrays or combinations of these (not shown) adapted to execute instructions. The UE 1430 further comprises software 1431, which is stored in or accessible by the UE 1430 and executable by the processing circuitry 1438. The software 1431 includes a client application 1432. The client application 1432 may be operable to provide a service to a human or non-human user via the UE 1430, with the support of the host computer 1410. In the host computer 1410, an executing host application 1412 may communicate with the executing client application 1432 via the OTT connection 1450 terminating at the UE 1430 and the host computer 1410. In providing the service to the user, the client application 1432 may receive request data from the host application 1412 and provide user data in response to the request data. The OTT connection 1450 may transfer both the request data and the user data. The client application 1432 may interact with the user to generate the user data that it provides.

It is noted that the host computer 1410, the base station 1420 and the UE 1430 illustrated in Fig. 14 may be similar or identical to the host computer 1330, one of base stations 1312a, 1312b, 1312c and one of UEs 1391 , 1392 of Fig. 13, respectively. This is to say, the inner workings of these entities may be as shown in Fig. 14 and independently, the surrounding network topology may be that of Fig. 13.

In Fig. 14, the OTT connection 1450 has been drawn abstractly to illustrate the communication between the host computer 1410 and the UE 1430 via the base station 1420, without explicit reference to any intermediary devices and the precise routing of messages via these devices. Network infrastructure may determine the routing, which it may be configured to hide from the UE 1430 or from the service provider operating the host computer 1410, or both. While the OTT connection 1450 is active, the network infrastructure may further take decisions by which it dynamically changes the routing (e.g., on the basis of load balancing consideration or reconfiguration of the network).

Wireless connection 1470 between the UE 1430 and the base station 1420 is in accordance with the teachings of the embodiments described throughout this disclosure. One or more of the various embodiments improve the performance of OTT services provided to the UE 1430 using the OTT connection 1450, in which the wireless connection 1470 forms the last segment. More precisely, the teachings of these embodiments may improve the reliability and latency, and thereby provide benefits such as reduced user waiting time.

A measurement procedure may be provided for the purpose of monitoring data rate, latency and other factors on which the one or more embodiments improve. There may further be an optional network functionality for reconfiguring the OTT connection 1450 between the host computer 1410 and the UE 1430, in response to variations in the measurement results. The measurement procedure and/or the network functionality for reconfiguring the OTT connection 1450 may be implemented in software 1411 and hardware 1415 of the host computer 1410 or in software 1431 and hardware 1435 of the UE 1430, or both. In embodiments, sensors (not shown) may be deployed in or in association with communication devices through which the OTT connection 1450 passes; the sensors may participate in the measurement procedure by supplying values of the monitored quantities exemplified above, or supplying values of other physical quantities from which the software 1411 , 1431 may compute or estimate the monitored quantities. The reconfiguring of the OTT connection 1450 may include message format, retransmission settings, preferred routing etc.; the reconfiguring need not affect the base station 1420, and it may be unknown or imperceptible to the base station 1420. Such procedures and functionalities may be known and practiced in the art. In certain embodiments, measurements may involve proprietary UE signaling facilitating the host computer 1410’s measurements of throughput, propagation times, latency and the like. The measurements may be implemented in that the software 1411 and 1431 causes messages to be transmitted, in particular empty or ‘dummy’ messages, using the OTT connection 1450 while it monitors propagation times, errors etc.

Fig. 15 is a flowchart illustrating a method implemented in a communication system, in accordance with an embodiment. The communication system includes a host computer, a base station and a UE which may be those described with reference to Fig. 13 and Fig. 14. For simplicity of the present disclosure, only drawing references to Fig. 15 will be included in this section. In step 1510, the host computer provides user data. In substep 1511 (which may be optional) of step 1510, the host computer provides the user data by executing a host application. In step 1520, the host computer initiates a transmission carrying the user data to the UE. In step 1530 (which may be optional), the base station transmits to the UE the user data which was carried in the transmission that the host computer initiated, in accordance with the teachings of the embodiments described throughout this disclosure. In step 1540 (which may also be optional), the UE executes a client application associated with the host application executed by the host computer.

Fig. 16 is a flowchart illustrating a method implemented in a communication system, in accordance with an embodiment. The communication system includes a host computer, a base station and a UE which may be those described with reference to Fig. 13 and Fig. 14. For simplicity of the present disclosure, only drawing references to Fig. 16 will be included in this section. In step 1610 of the method, the host computer provides user data. In an optional substep (not shown) the host computer provides the user data by executing a host application. In step 1620, the host computer initiates a transmission carrying the user data to the UE. The transmission may pass via the base station, in accordance with the teachings of the embodiments described throughout this disclosure. In step 1630 (which may be optional), the UE receives the user data carried in the transmission.

Fig. 17 is a flowchart illustrating a method implemented in a communication system, in accordance with an embodiment. The communication system includes a host computer, a base station and a UE which may be those described with reference to Fig. 13 and Fig. 14. For simplicity of the present disclosure, only drawing references to Fig. 17 will be included in this section. In step 1710 (which may be optional), the UE receives input data provided by the host computer. Additionally or alternatively, in step 1720, the UE provides user data. In substep 1721 (which may be optional) of step 1720, the UE provides the user data by executing a client application. In substep 1711 (which may be optional) of step 1710, the UE executes a client application which provides the user data in reaction to the received input data provided by the host computer. In providing the user data, the executed client application may further consider user input received from the user. Regardless of the specific manner in which the user data was provided, the UE initiates, in substep 1730 (which may be optional), transmission of the user data to the host computer. In step 1740 of the method, the host computer receives the user data transmitted from the UE, in accordance with the teachings of the embodiments described throughout this disclosure. Fig. 18 is a flowchart illustrating a method implemented in a communication system, in accordance with an embodiment. The communication system includes a host computer, a base station and a UE which may be those described with reference to Fig. 13 and Fig. 14. For simplicity of the present disclosure, only drawing references to Fig. 18 will be included in this section. In step 1810 (which may be optional), in accordance with the teachings of the embodiments described throughout this disclosure, the base station receives user data from the UE. In step 1820 (which may be optional), the base station initiates transmission of the received user data to the host computer. In step 1830 (which may be optional), the host computer receives the user data carried in the transmission initiated by the base station.

The disclosure has been described above with reference to embodiments thereof. It should be understood that various modifications, alternations and additions can be made by those skilled in the art without departing from the spirits and scope of the disclosure. Therefore, the scope of the disclosure is not limited to the above particular embodiments but only defined by the claims as attached.

Claims

1. A method (200) in a network device, comprising: configuring (210) a Random Access Response, RAR, repetition for a terminal device configured with a prioritized service, a network slice associated with the prioritized service, or a prioritized radio access network type.

2. The method (200) of claim 1 , wherein said configuring (210) comprises: transmitting an indication of a number of RAR repetitions enabled for terminal devices configured with the prioritized service, the network slice associated with the prioritized service, or the prioritized radio access network type, via system information or Physical Broadcast Channel, PBCH.

3. The method (200) of claim 1 , wherein said configuring (210) comprises: transmitting, to the terminal device, an indication of a number of RAR repetitions via dedicated Radio Resource Control, RRC, signaling.

4. The method (200) of claim 1 , further comprising: receiving, from the terminal device, a random access preamble; and determining that the terminal device is configured with the prioritized service, the network slice associated with the prioritized service, or the prioritized radio access network type, wherein said configuring comprises, in response to said determining: transmitting, to the terminal device, an indication of a number of RAR repetitions in Downlink Control Information, DCI.

5. The method (200) of any of claims 1 -4, further comprising: transmitting, to the terminal device, an RAR for the number of RAR repetitions.

6. The method (200) of any of claims 1 -5, wherein the prioritized service comprises a Mission Critical, MC, service, a multimedia priority service, or a Small Data Transmission, SDT, service, or the prioritized radio access network type comprises Non-Territorial Network, NTN.

7. The method (200) of claim 6, wherein the NTN comprises a satellite network, a High-Altitude Platform Station, HAPS, network, or a base station network on an aerial vehicle.

8. A method (600) in a terminal device, comprising: receiving (610), from a network device, a configuration of a Random Access Response, RAR, repetition for a prioritized service, a network slice associated with the prioritized service, or a prioritized radio access network type.

9. The method (600) of claim 8, wherein the configuration is received via system information or Physical Broadcast Channel, PBCH, and comprises an indication of a number of RAR repetitions enabled for terminal devices configured with the prioritized service, the network slice associated with the prioritized service, or the prioritized radio access network type.

10. The method (600) of claim 8, wherein the configuration is received via dedicated Radio Resource Control, RRC, signaling and comprises an indication of a number of RAR repetitions.

11. The method (600) of claim 8, further comprising: transmitting, to the network device, a random access preamble, wherein the configuration is received via Downlink Control Information, DCI, and comprises an indication of a number of RAR repetitions.

12. The method (600) of any of claims 9-11 , further comprising: receiving, from the network device, an RAR in at least one of the number of RAR repetitions.

13. The method (600) of any of claims 8-12, wherein the prioritized service comprises a Mission Critical, MC, service, a multimedia priority service, or a Small Data Transmission, SDT, service, or the prioritized radio access network type comprises Non-Territorial Network, NTN.

14. The method (600) of claim 13, wherein the NTN comprises a satellite network, a High-Altitude Platform Station, HAPS, network, or a base station network on an aerial vehicle.

15. A method (300) in a network device, comprising: configuring (310) a parameter for Random Access Response, RAR, transmission or reception for a terminal device configured with a service having a priority level, a network slice associated with the service, or a radio access network type having a network priority level.

16. The method (300) of claim 15, wherein the parameter comprises a first RAR window which is different from a second RAR window for RAR reception for another terminal device configured with another service having another priority level lower than the priority level, another network slice associated with the other service, or another radio access network type having another network priority level lower than the network priority level.

17. The method (300) of claim 16, wherein the first RAR window is shorter than the second RAR window.

18. The method (300) of claim 15, wherein the parameter comprises: a first Transport Block, TB, scaling factor which is smaller than a second TB scaling factor for RAR transmission for another terminal device configured with another service having another priority level lower than the priority level, another network slice associated with the other service, or another radio access network type having another network priority level lower than the network priority level, and/or a first Modulation and Coding Scheme, MCS, index which is smaller than a second MCS index for RAR transmission for another terminal device configured with another service having another priority level lower than the priority level, another network slice associated with the other service, or another radio access network type having another network priority level lower than the network priority level.

19. The method (300) of claim 15, wherein the parameter comprises an indication of a first Modulation and Coding Scheme, MCS, table which has lower spectral efficiency than a second MCS table for RAR transmission for another terminal device configured with another service having another priority level lower than the priority level, another network slice associated with the other service, or another radio access network type having another network priority level lower than the network priority level.

20. The method (300) of claim 15, wherein the parameter indicates that an earliest usable downlink symbol or a p/2 Binary Phase Shift Keying, BPSK, modulation is to be used for RAR transmission.

21. The method (300) of any of claims 15-20, further comprising: receiving, from the terminal device, a random access preamble; determining that the terminal device is configured with the service having the priority level, the network slice associated with the service, or the radio access network type having the network priority level; and transmitting, to the terminal device, an RAR in accordance with the parameter.

22. The method (300) of any of claims 15-21 , wherein the service comprises a Mission Critical, MC, service, a multimedia priority service, or a Small Data Transmission, SDT, service, or the radio access network type comprises Non-Territorial Network, NTN.

23. The method (300) of claim 22, wherein the NTN comprises a satellite network, a High-Altitude Platform Station, HAPS, network, or a base station network on an aerial vehicle.

24. A method (400) in a network device, comprising: receiving (410), from a first terminal device configured with a first service having a first priority level, a first network slice associated with the first service, or a first radio access network type having a first network priority level, a first random access preamble mapped to a first Synchronization Signal and Physical Broadcast Channel ‘PBCH’ Block, SSB; and transmitting (420), to the first terminal device, a first Random Access Response, RAR, via a first SSB, beam corresponding to the first SSB, or an SSB beam closer to the first SSB beam than a second SSB beam via which a second RAR for a second terminal device is transmitted, the second terminal device being configured with a second service having a second priority level lower than the first priority level, a second network slice associated with the second service, or a second radio access network type having a second network priority level lower than the first network priority level and having transmitted a second random access preamble mapped to the first SSB.

25. The method (400) of claim 24, wherein the first service comprises a Mission Critical, MC, service, a multimedia priority service, or a Small Data Transmission, SDT, service, and/or the first radio access network type comprises Non-Territorial Network, NTN.

26. The method (400) of claim 25, wherein the NTN comprises a satellite network, a High-Altitude Platform Station, HAPS, network, or a base station network on an aerial vehicle.

27. A method (700) in a terminal device, comprising: receiving (710), from a network device, a parameter for Random Access Response, RAR, transmission or reception for a service having a priority level, a network slice associated with the service, or a radio access network type having a network priority level.

28. The method (700) of claim 27, wherein the parameter comprises a first RAR window which is different from a second RAR window for RAR reception for another service having another priority level lower than the priority level, another network slice associated with the other service, or another radio access network type having another network priority level lower than the network priority level.

29. The method (700) of claim 28, wherein the first RAR window is shorter than the second RAR window.

30. The method (700) of claim 27, wherein the parameter comprises: a first Transport Block, TB, scaling factor which is smaller than a second TB scaling factor for RAR transmission for another service having another priority level lower than the priority level, another network slice associated with the other service, or another radio access network type having another network priority level lower than the network priority level, and/or a first Modulation and Coding Scheme, MCS, index which is smaller than a second MCS index for RAR transmission for another service having another priority level lower than the priority level, another network slice associated with the other service, or another radio access network type having another network priority level lower than the network priority level.

31. The method (700) of claim 27, wherein the parameter comprises an indication of a first Modulation and Coding Scheme, MCS, table which has lower spectral efficiency than a second MCS table for RAR transmission for another service having another priority level lower than the priority level, another network slice associated with the other service, or another radio access network type having another network priority level lower than the network priority level.

32. The method (700) of claim 27, wherein the parameter indicates that an earliest usable downlink symbol or a p/2 Binary Phase Shift Keying, BPSK, modulation is to be used for RAR transmission.

33. The method (700) of any of claims 27-32, further comprising: receiving, from the network device, an RAR in accordance with the parameter.

34. The method (700) of any of claims 27-33, wherein the service comprises a Mission Critical, MC, service, a multimedia priority service, or a Small Data Transmission, SDT, service, and/or the radio access network type comprises Non-Territorial Network, NTN.

35. The method (700) of claim 34, wherein the NTN comprises a satellite network, a High-Altitude Platform Station, HAPS, network, or a base station network on an aerial vehicle.

36. A method (500) in a network device, comprising: receiving (510) a plurality of random access preambles from a plurality of terminal devices, respectively, in one random access occasion; and transmitting (520) one or more Random Access Responses, RARs, to one or more of the plurality of terminal devices based on priority levels of respective services or network priority levels of respective radio access network types, the plurality of terminal devices being configured with the respective services, network slices associated with the respective services, or the respective radio access network types.

37. The method (500) of claim 36, wherein said transmitting (520) comprises: transmitting an RAR message containing one or more RARs for one or more of the plurality of terminal devices that are configured with services each having a priority level higher than or equal to a priority level threshold, network slices each associated with a service having a priority level higher than or equal to the priority level threshold, or radio access network types each having a network priority level higher than or equal to a network priority level threshold.

38. The method (500) of claim 37, wherein said transmitting (520) further comprises: transmitting one or more further RAR messages each containing one or more RARs for one or more of the plurality of terminal devices that are configured with services having one of the priority levels that is lower than the priority level threshold or network slices associated with services having one of the priority levels that is lower than the priority level threshold, in a descending order of the priority levels, until a maximum number of admissible terminal devices is reached, or transmitting one or more further RAR messages each containing one or more RARs for one or more of the plurality of terminal devices that are configured with radio access network types having one of the network priority levels that is lower than the network priority level threshold, in a descending order of the network priority levels, until a maximum number of admissible terminal devices is reached.

39. The method (500) of claim 36, wherein said transmitting (520) comprises: transmitting an RAR message obtained by adding RARs for the plurality of terminal devices, in a descending order of the priority levels or the network priority levels, until a maximum number of allowable RARs in one RAR message or a maximum number of admissible terminal devices is reached.

40. The method (500) of claim 36, wherein the plurality of random access preambles are mapped to different Synchronization Signal and Physical Broadcast Channel ‘PBCH’ Blocks, SSBs, and said transmitting (520) comprises: transmitting the one or more RARs to the one or more terminal devices via one SSB beam corresponding to an SSB to which the random access preamble from one of the plurality of terminal devices that is configured with a service having a highest priority level among the priority levels, a network slice associated with the service having the highest priority level, or a radio access network type having a highest priority level among the network priority levels is mapped, or a beam quasi-co-located with the one SSB beam.

41. The method (500) of claim 40, further comprising: transmitting Downlink Control Information, DCI, for scheduling the one or more RARs to the one or more terminal devices via the one SSB beam or a beam quasi-co-located with the one SSB beam.

42. A method (800) in a terminal device, comprising: transmitting (810), to a network device, a random access preamble; monitoring (820) Downlink Control Information, DCI, from the network device for scheduling a Random Access Response, RAR, message; determining (830) that the RAR message does not contain an RAR for the terminal device; and monitoring (840), within an RAR window, further DCI from the network device for scheduling a further RAR message.

43. The method (800) of claim 42, wherein the DCI and the further DCI are addressed to a Radio Network Temporary Identifier, RNTI, associated with a random access occasion in which the random access preamble is transmitted.

44. A network device (1000), comprising a transceiver (1010), a processor (1020) and a memory (1030), the memory (1030) comprising instructions executable by the processor (1020) whereby the network device (1000) is operative to perform the method according to any of claims 1-7, 15-26, or 36-41.

45. A computer readable storage medium having computer program instructions stored thereon, the computer program instructions, when executed by a processor in a network device, causing the network device to perform the method according to any of claims 1-7, 15-26, or 36-41.

46. A terminal device (1200), comprising a transceiver (1210), a processor (1220) and a memory (1230), the memory (1230) comprising instructions executable by the processor (1220) whereby the terminal device (1200) is operative to perform the method according to any of claims 8-14, 27-35, or 42-43.

47. A computer readable storage medium having computer program instructions stored thereon, the computer program instructions, when executed by a processor in a terminal device, causing the terminal device to perform the method according to any of claims 8-14, 27-35, or 42-43.