US-12621876-B2 - Method and apparatus for random access

US12621876B2US 12621876 B2US12621876 B2US 12621876B2US-12621876-B2

Abstract

A method for random access which may be performed by a terminal device comprises receiving configuration information for a random access procedure from a network node. The method further comprises determining an association between random access resource and shared channel resource for the random access procedure, according to the configuration information. The association is based at least in part on a configuration of the shared channel resource. An association between signaling transmissions in a random access procedure can be configured flexibly and efficiently.

Inventors

Zhipeng Lin
Robert Mark Harrison

Assignees

TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)

Dates

Publication Date: 20260505
Application Date: 20200427
Priority Date: 20190503

Claims (17)

1 . A method performed by a terminal device, comprising: receiving configuration information for a random access procedure from a network node; and determining an association between a random access resource and a shared channel resource for the random access procedure, according to the configuration information, wherein the association is based at least in part on a configuration of the shared channel resource, wherein the association maps a preamble in a random access occasion to a resource unit in a shared channel occasion, wherein a time resource configured for the resource unit corresponds to a synchronization signal and physical broadcast channel block associated with the preamble, wherein mapping of the preamble in the random access occasion to the resource unit in the shared channel occasion is according to a mapping rule, wherein the mapping rule comprises mapping preambles having consecutive identifiers to different shared channel occasions, and wherein the mapping rule is based on a demodulation reference signal port configured for the resource unit and a demodulation reference signal sequence initialization configured for the resource unit.
2 . The method according to claim 1 , wherein the configuration of the shared channel resource comprises: configuration of shared channel occasions with one or more sizes by enabling the shared channel occasions to be configured with a variable number of physical resource blocks.
3 . The method according to claim 1 , wherein the mapping rule is further based on one or more following mapping factors: orthogonality of preambles; a probability of transmission colliding on the shared channel occasion; a size of the shared channel occasion; and time resource configured for the resource unit.
4 . The method according to claim 3 , wherein the mapping factors have different priorities.
5 . The method according to claim 3 , wherein the mapping rule comprises: mapping preambles having consecutive identifiers to different shared channel occasions.
6 . The method according to claim 1 , wherein the mapping rule comprises: mapping preambles associated with the synchronization signal and physical broadcast channel block to multiple shared channel occasions with different sizes.
7 . The method according to claim 1 , wherein the shared channel occasion associated with the synchronization signal and physical broadcast channel block is configured with a time resource different from another shared channel occasion associated with a different synchronization signal and physical broadcast channel block.
8 . The method according to claim 1 , further comprising: performing the random access procedure, according to the determining of the association between the random access resource and the shared channel resource.
9 . The method according to claim 1 , wherein the random access procedure is a two-step random access procedure.
10 . A method performed by a network node, comprising: determining an association between a random access resource and a shared channel resource for a random access procedure, wherein the association is based at least in part on a configuration of the shared channel resource, wherein the association is based on a mapping of a preamble in a random access occasion to a resource unit in a shared channel occasion, wherein a time resource configured for the resource unit corresponds to a synchronization signal and physical broadcast channel block associated with the preamble, wherein mapping of the preamble in the random access occasion to the resource unit in the shared channel occasion is according to a mapping rule, wherein the mapping rule comprises mapping preambles having consecutive identifiers to different shared channel occasions, and wherein the mapping rule is based on a demodulation reference signal port configured for the resource unit and a demodulation reference signal sequence initialization configured for the resource unit; and transmitting configuration information about the association for the random access procedure to a terminal device.
11 . The method according to claim 10 , wherein the configuration of the shared channel resource comprises: configuration of shared channel occasions with one or more sizes by enabling the shared channel occasions to be configured with a variable number of physical resource blocks.
12 . The method according to claim 10 , wherein the mapping rule is further based on one or more following mapping factors: orthogonality of preambles; a probability of transmission colliding on the shared channel occasion; a size of the shared channel occasion; and time resource configured for the resource unit.
13 . The method according to claim 12 , wherein the mapping factors have different priorities.
14 . The method according to claim 12 , wherein the mapping rule comprises: mapping preambles having consecutive identifiers to different shared channel occasions.
15 . The method according to claim 10 , wherein the mapping rule comprises: mapping preambles associated with the synchronization signal and physical broadcast channel block to multiple shared channel occasions with different sizes.
16 . The method according to claim 10 , wherein the shared channel occasion associated with the synchronization signal and physical broadcast channel block is configured with a time resource different from another shared channel occasion associated with a different synchronization signal and physical broadcast channel block.
17 . A terminal device, comprising: one or more processors; and one or more memories comprising computer program codes which, when executed by the one or more processors, cause the terminal device to: receive configuration information for a random access procedure from a network node; and determine an association between a random access resource and a shared channel resource for the random access procedure, according to the configuration information, wherein the association is based at least in part on a configuration of the shared channel resource, wherein the association maps a preamble in a random access occasion to a resource unit in a shared channel occasion, wherein a time resource configured for the resource unit corresponds to a synchronization signal and physical broadcast channel block associated with the preamble, wherein mapping of the preamble in the random access occasion to the resource unit in the shared channel occasion is according to a mapping rule, wherein the mapping rule comprises mapping preambles having consecutive identifiers to different shared channel occasions, and wherein the mapping rule is based on a demodulation reference signal port configured for the resource unit and a demodulation reference signal sequence initialization configured for the resource unit.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS This application is a National stage of International Application No. PCT/EP2020/061642, filed Apr. 27, 2020, which claims priority to International Application No. PCT/CN2019/085434, filed May 3, 2019, which are hereby incorporated by reference. FIELD OF THE INVENTION The present disclosure generally relates to communication networks, and more specifically, to method and apparatus for random access. BACKGROUND This section introduces aspects that may facilitate a better understanding of the disclosure. Accordingly, the statements of this section are to be read in this light and are not to be understood as admissions about what is in the prior art or what is not in the prior art. Communication service providers and network operators have been continually facing challenges to deliver value and convenience to consumers by, for example, providing compelling network services and performance. With the rapid development of networking and communication technologies, wireless communication networks such as long-term evolution (LTE) and new radio (NR) networks are expected to achieve high traffic capacity and end-user data rate with lower latency. In order to connect to a network node, a random access (RA) procedure may be initiated for a terminal device. In the RA procedure, system information (SI) and synchronization signals (SS) as well as the related radio resource and transmission configuration can be informed to the terminal device by control information from the network node. The RA procedure can enable the terminal device to establish a session for a specific service with the network node. Thus, it is desirable to enhance the configuration and performance of the RA procedure. SUMMARY This summary is provided to introduce a selection of concepts in a simplified form that are further described below in the detailed description. This summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used to limit the scope of the claimed subject matter. A wireless communication network such as a NR/5G network may be able to support flexible network configuration. Various signaling approaches (e.g., a four-step approach, a two-step approach, etc.) may be used for a RA procedure of a terminal device to set up a connection with a network node. For the RA procedure, there may be a specific association between a synchronization signal and physical broadcast channel block (which is also known as a SS/PBCH block or SSB for short) and a time-frequency physical random access channel (PRACH) occasion (which is also known as a RA occasion or RO for short). In a two-step RA procedure, the terminal device can transmit a RA preamble together with the physical uplink shared channel (PUSCH) in a message (which is also known as message A or msgA for short) to the network node, and receive a response message (which is also known as message B or msgB for short) from the network node. The msgA PUSCH can be transmitted in a PUSCH occasion (PO) configured with one or more resource units (RUs), and the RA preamble can be transmitted in a RO. It may be desirable to configure signaling transmissions for a RA procedure more flexibly and efficiently while implementing association of resource configuration in a RO and a PO. Various embodiments of the present disclosure propose a solution for RA, which can support adaptive association configuration for a RA procedure such as a two-step RA procedure, for example, by providing flexibility for mapping of a SSB associated preamble in a RO to a PUSCH RU in a PO, so as to increase diversity of resource configuration and improve performance of the RA procedure. It can be realized that the terms “PRACH occasion”, “random access channel (RACH) occasion” or “RA occasion” mentioned herein may refer to a time-frequency resource usable for the preamble transmission in a RA procedure, which may also be referred to as “random access occasion (RO)”. These terms may be used interchangeably in this document. In accordance with some exemplary embodiments, a RO usable for the preamble transmission in two-step RA may be called a two-step RO, while a RO usable for the preamble transmission in four-step RA may be called a four-step RO. Similarly, it can be realized that the terms “PUSCH occasion”, “uplink shared channel occasion” or “shared channel occasion” mentioned herein may refer to a time-frequency resource usable for PUSCH transmission in a RA procedure, which may also be referred to as “physical uplink shared channel occasion (PO)”. These terms may be used interchangeably in this document. According to a first aspect of the present disclosure, there is provided a method performed by a network node. The method comprises determining an association between RA resource and shared channel resource for a RA procedure, based at least in part on a configuration of the shared channel resource. The method further co