Method and Apparatus for Random Access Procedure

Abstract

Embodiments of the present disclosure provide methods and apparatuses for random access procedure. A method performed by a terminal device comprises transmitting multiple preambles on different transmission chains of the terminal device to a network node. The multiple preambles are associated with a same or different synchronization signal and physical broadcast channel block (SSB).

Description

Claims

1-158. (canceled)

159. A method performed by a terminal device configured to operate in a wireless communication system, the method comprising: transmitting multiple preambles on different transmission chains of the terminal device to a network node of the wireless communication system, wherein the multiple preambles are associated with a same or different synchronization signal and physical broadcast channel block (SSB).

160. The method according to claim 159, wherein the multiple preambles comprise preambles mapped to a best SSB and are transmitted in different directions.

161. The method according to claim 159, wherein one of the following applies: the multiple preambles are transmitted simultaneously during a single random access channel occasion (RO);the multiple preambles are transmitted in different time-division multiplexed Ros; orthe multiple preambles are transmitted simultaneously in different frequency-division multiplexed ROs.

162. The method according to claim 159, wherein: when the multiple preambles are associated with the same SSB, the following applies: when one SSB maps to one RO, the multiple preambles are transmitted in the same RO;when one SSB maps to multiple frequency division multiplexed ROs, the multiple preambles are transmitted in a same RO or different ROs;and when the multiple preambles are associated with different SSBs, the following applies: when the different SSBs map to a same RO, the multiple preambles are transmitted in the same RO; andwhen the different SSBs map to multiple frequency division multiplexed ROs, the multiple preambles are transmitted in the multiple frequency division multiplexed ROs.

163. The method according to claim 159, wherein: the multiple preambles are simultaneously transmitted in the same RO when coherent closed loop transmit diversity is used for the transmission; andthe multiple preambles are simultaneously transmitted in different frequency division multiplexed ROs when an open loop transmit diversity or a non-coherent closed loop transmit diversity is used for the transmission.

164. The method according to claim 159, wherein at least one of the following applies: the multiple preambles are transmitted at a same power level;each of the multiple preambles is transmitted using a different spatial domain transmission filter; andthe multiple preambles contain the preambles when a channel quality measure is greater than a threshold.

165. The method according to claim 159, wherein at least one of the following applies: a set of random access channel occasions (ROs) is configured for transmission of a same preamble and each set of ROs corresponds to a different transmission chain of the terminal device;the multiple preambles are associated with at least two preamble identifiers (IDs) and each preamble identifier ID corresponds to a different transmission chain of the terminal device; anda set of scrambling sequences are used to scramble preambles and each scrambling sequence corresponds to a different transmission chain of the terminal device.

166. The method according to claim 159, wherein: the multiple preambles are determined based on at least one of the following: a preamble group in one RO, different ROs, or terminal coherency capability;consecutive ones of the multiple preambles are grouped when the terminal device requires a number of consecutive preambles to transmit; andthe multiple preambles are divided when the non-coherent terminal device requires non-coherent, partially coherent, or fully coherent preamble transmission.

167. The method according to claim 159, wherein a preamble index from every RO is reserved by System Information Block Type 1 (SIB1) for a terminal device.

168. The method according to claim 159, wherein the transmission of the multiple preambles is based on a mapping between the multiple preambles and respective virtual antenna ports of the terminal device.

169. The method according to claim 159, further comprising: receiving one or more random access responses (RARs) from the network node, wherein each random access response includes an identifier of a corresponding preamble and indicates to the terminal device to transmit a physical uplink shared channel (PUSCH); andtransmitting the PUSCH using a same spatial domain transmission filter that was used to transmit the one or more preambles corresponding to the one or more identifiers received.

170. The method according to claim 169, further comprising, after transmitting the PUSCH, performing one or more subsequent transmissions of the PUSCH using the same spatial domain filter.

171. The method according to claim 169, wherein: when the RAR includes or indicates a precoder, the PUSCH is transmitted using the precoder; andwhen the RAR does not include or indicate a precoder, the PUSCH is transmitted using only one antenna port that was used to transmit the one or more preambles corresponding to the one or more identifiers received.

172. The method according to claim 169, wherein the RAR indicates a number of PUSCH layers and the PUSCH is transmission as a multiple-layer PUSCH transmission using the indicated number of PUSCH layers.

173. The method according to claim 169, wherein when PUSCH repetition is configured for PUSCH and the RAR includes or indicates one or more precoders, the PUSCH is transmitted in multiple PUSCH repetitions, all of which use the indicated one or more precoders.

174. The method according to claim 169, wherein at least one of the following applies: the PUSCH is transmitted using a precoder that is predefined or configured via a System Information Block Type 1 (SIB1); andthe RAR includes or indicates a further precoder, which is used for subsequent PUSCH transmissions.

175. The method according to claim 169, wherein one of the following applies: the preamble and the PUSCH are transmitted together as a message A in a two-step random access procedure; orthe preamble and the PUSCH are transmitted as a message 1 and message 3 respectively in a four-step random access procedure.

176. A terminal device configured to operate in a wireless communication system, the terminal device comprising: a processor; anda memory operably coupled to the processor and containing instructions executable by said processor, wherein execution of the instructions configures the terminal device to: transmit multiple preambles on different transmission chains of the terminal device to a network node of the wireless communication system, wherein the multiple preambles are associated with a same or different synchronization signal and physical broadcast channel block (SSB).

177. The terminal device according to claim 176, wherein one of the following applies: the multiple preambles are transmitted simultaneously during a single random access channel occasion (RO);the multiple preambles are transmitted in different time-division multiplexed ROs; orthe multiple preambles are transmitted simultaneously in different frequency-division multiplexed ROs.

178. A network node, comprising: a processor; anda memory coupled to the processor, said memory containing instructions executable by said processor, whereby said network node is operative to: receive multiple preambles from a terminal device, wherein the multiple preambles are associated with a same or different synchronization signal and physical broadcast channel block (SSB).