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EP-3869900-B1 - RANDOM ACCESS METHOD, TERMINAL DEVICE AND NETWORK DEVICE

EP3869900B1EP 3869900 B1EP3869900 B1EP 3869900B1EP-3869900-B1

Inventors

  • HE, CHUANFENG
  • WANG, SHUKUN

Dates

Publication Date
20260506
Application Date
20181027

Claims (13)

  1. A random access method, characterized by comprising: receiving, by a terminal device, indication information sent by a network device, wherein the indication information is used for indicating at least one random access preamble in a plurality of random access preambles, and the plurality of random access preambles correspond to a random access response receiving window (410); and determining, by the terminal device, a power for sending a physical uplink shared channel, PUSCH, according to a transmission power of a first random access preamble in the at least one random access preamble (420); wherein the indication information comprises power of at least two preambles and the terminal device selects the preamble with the lowest power as the first preamble from which it determines the power for sending the PUSCH; wherein the method further comprises: receiving, by the terminal device, a random access response sent by the network device; wherein the indication information is carried in the random access response, and random access-radio network temporary identifiers, RA-RNTIs, corresponding to at least two random access preambles in the plurality of random access preambles are same; wherein determining, by the terminal device, a power for sending a physical uplink shared channel, PUSCH, according to a transmission power of a first random access preamble in the at least one random access preamble (420), comprises: determining the power for sending the PUSCH according to the transmission power of the first random access preamble and a preset corresponding relationship between a transmission power of a random access preamble and a power of the PUSCH.
  2. The method of claim 1, wherein transmission powers of at least two random access preambles in the plurality of random access preambles are different, the first random access preamble has a lowest transmission power in the at least one random access preamble.
  3. The method of claim 1, wherein the indication information is carried in a random access-radio network temporary identifier, RA-RNTI, RA-RNTIs corresponding to the plurality of random access preambles are different from each other, and the method further comprises: determining, by the terminal device, the first random access preamble according to the RA-RNTI.
  4. The method of any one of claims 1 to 3, wherein if the indication information is used for indicating at least two random access preambles in the plurality of random access preambles, the method further comprises: selecting, by the terminal device, the first random access preamble from random access preambles corresponding to random access responses, wherein the random access responses comprise at least two random access responses.
  5. A random access method, characterized by comprising: sending, by a network device, indication information to a terminal device, wherein the indication information is used for indicating at least one random access preamble in random access preambles detected by the network device, the random access preambles detected by the network device are at least part of a plurality of random access preambles sent by the terminal device, the at least one random access preamble comprises a first random access preamble, wherein the indication information comprises power of at least two preambles and the terminal device selects the preamble with the lowest power as the first preamble from which it determines the power for sending the PUSCH; and the plurality of random access preambles correspond to a random access response receiving window (510); wherein a transmission power of the first random access preamble is used for determining a power for sending a physical uplink shared channel, PUSCH; wherein the method further comprises: detecting, by the network device, random access preambles in the plurality of random access preambles; responding to, by the network device, at least part of the detected random access preambles; and sending, by the network device, a random access response to the terminal device, wherein the random access response corresponds to a random access preamble to which the network device responds; wherein the indication information is carried in the random access response, if the random access preambles detected by the network device comprise at least two random access preambles, random access-wireless network temporary identifiers, RA-RNTIs, corresponding to the at least two access preambles of the random access preambles detected by the network device are same; wherein the transmission power of the first random access preamble and a preset corresponding relationship between a transmission power of a random access preamble and a power of the PUSCH are used for determining the power for sending the PUSCH.
  6. The method of claim 5, wherein transmission powers of at least two random access preambles in the plurality of random access preambles are different, if the random access preambles detected by the network device comprise at least two random access preambles, the first random access preamble has a lowest transmission power in the random access preambles detected by the network device.
  7. A terminal device (600), characterized by comprising: a communication unit (610), configured to receive indication information sent by a network device, wherein the indication information is used for indicating at least one random access preamble in a plurality of random access preambles, and the plurality of random access preambles correspond to a random access response receiving window; and a processing unit (620), configured to determine a power for sending a physical uplink shared channel, PUSCH, according to a transmission power of a first random access preamble in the at least one random access preamble; wherein the indication information comprises power of at least two preambles and the terminal device selects the preamble with the lowest power as the first preamble from which it determines the power for sending the PUSCH; wherein the communication unit (610) is further configured to receive a random access response sent by the network device; wherein the indication information is carried in the random access response, and random access-radio network temporary identifiers, RA-RNTIs, corresponding to at least two random access preambles in the plurality of random access preambles are same; wherein the processing unit (620) is specifically configured to: determine the power for sending the PUSCH according to the transmission power of the first random access preamble and a preset corresponding relationship between a transmission power of a random access preamble and a power of the PUSCH.
  8. The terminal device of claim 7, wherein transmission powers of at least two random access preambles in the plurality of random access preambles are different, the first random access preamble has a lowest transmission power in the at least one random access preamble.
  9. The terminal device of claim 7, wherein the indication information is carried in a random access-radio network temporary identifier, RA-RNTI, RA-RNTIs corresponding to the plurality of random access preambles are different from each other, the processing unit (620) is further configured to: determine the first random access preamble according to the RA-RNTI.
  10. The terminal device of any one of claims 7 to 9, wherein the communication unit (610) is further configured to: receive configuration information sent by the network device, wherein the configuration information comprises time-frequency resources for the terminal device to send the plurality of random access preambles; and send the plurality of random access preambles to the network device by using the time-frequency resources.
  11. A network device (700), characterized by comprising: a communication unit (710), configured to send indication information to a terminal device, wherein the indication information is used for indicating at least one random access preamble in random access preambles detected by the network device, the random access preambles detected by the network device are at least part of a plurality of random access preambles sent by the terminal device, the at least one random access preamble comprises a first random access preamble, wherein the indication information comprises power of at least two preambles and the terminal device selects the preamble with the lowest power as the first preamble from which it determines the power for sending the PUSCH; and the plurality of random access preambles correspond to a random access response receiving window; wherein a transmission power of the first random access preamble is used for determining a power for sending a physical uplink shared channel, PUSCH; wherein the network device further comprises: a processing unit, configured to detect random access preambles in the plurality of random access preambles; wherein the processing unit is further configured to respond to at least part of the detected random access preambles; and the communication unit (710) is further configured to: send a random access response to the terminal device, wherein the random access response corresponds to a random access preamble to which the processing unit responds; wherein the indication information is carried in the random access response, if the random access preambles detected by the network device comprise at least two random access preambles, random access-wireless network temporary identifiers, RA-RNTIs, corresponding to the at least two access preambles of the random access preambles detected by the network device are same; wherein the transmission power of the first random access preamble and a preset corresponding relationship between a transmission power of a random access preamble and a power of the PUSCH are used for determining the power for sending the PUSCH.
  12. The network device of claim 11, wherein transmission powers of at least two random access preambles in the plurality of random access preambles are different, if the random access preamble detected by the network device comprises at least two random access preambles, the first random access preamble has a lowest transmission power in the random access preambles detected by the network device.
  13. The network device of claim 11 or 12, wherein the communication unit (710) is further configured to: send configuration information to the terminal device, wherein the configuration information comprises time-frequency resources for the network device to receive the plurality of random access preambles; and receive the plurality of random access preambles sent by the terminal device, by using the time-frequency resources.

Description

Technical Field Implementations of the present disclosure relate to a field of communication, and more specifically, to a random access method, a terminal device and a network device. Background Random access is a most basic function of a cellular system. In a New Radio (NR) system (or called 5G system or 5G network), a four-step random access procedure similar to that in Long Term Evolution (LTE) is adopted. An NR system supports a transmission on an unlicensed spectrum. When a communication device communicates on an unlicensed spectrum, it is needed to be based on a principle of Listen Before Talk (LBT). That is to say, the communication device needs to listen to a channel before sending a signal on the unlicensed spectrum channel. Only when a result of the channel listening is that the channel is idle can the communication device send the signal. If a result of a channel listening performed by the communication device on the unlicensed spectrum is that the channel is busy, the signal cannot be sent. Therefore, messages in the random access procedure may only be sent when the communication device obtains an idle channel. After sending a random access preamble (that is message1, MSG1), the terminal device needs to receive a Random Access Response (RAR, that is message 2, MSG2) in an RAR receiving window. If the RAR is not received, the terminal device sends the preamble again. Since the LBT needs to be performed multiple times in a process of sending the preamble, and every time the performing of the LBT has a possibility of failure, it will cause a great delay of a random access procedure. The terminal device may send the preamble and receive the RAR within a Maximum Channel Occupation Time (MCOT), and only needs to perform the LBT once. Therefore, to reduce a delay of a random access, the terminal device may send multiple preambles after LBT is successful and before the RAR receiving window ends. However, in a scenario that the terminal device sends multiple preambles, how the terminal device determines a power for sending a Physical Uplink Shared Channel (PUSCH) is not clearly specified at present. CN 018476480 A discloses a random access method for user equipment. ALCATEL-LUCENT ET AL: "Correction to PUSCH/PUCCH transmit power after PRACH power ramping", 3GPP DRAFT; 36213_CR0417R1_(REL-11)_R1-132673, 7 June 2013, XP051638333, discloses correction to PUSCH/PUCCH transmit power after PRACH power ramping. Bertrand Pierre ET AL: "7 Random Access", LTE - the UMTS long term evolution : from theory to practice ; [Including release 10 for L TE-advanced], 29 August 2011 (2011-08-29), pages 371-387, XP055855720, ISBN: 978-0-470-66025-6, discloses Random Access. NOKIA ET AL: "Remaining details on PRACH procedure", 3GPP DRAFT; R1-1716138_REMAINING DETAILS ON RACH PROCEDURE, 17 September 2017, XP051339596, discloses random access procedures. Summary The invention is specified by the independent claims. Further embodiments are specified in the dependent claims. In a first aspect, there is provided a random access method, including receiving, by a terminal device, indication information sent by a network device, wherein the indication information is used for indicating at least one random access preamble in multiple random access preambles, and the multiple random access preambles correspond to a random access response receiving window; determining, by the terminal device, a power for sending a physical uplink shared channel (PUSCH) according to a transmission power of a first random access preamble in the at least one random access preamble, wherein the indication information comprises power of at least two preambles and the terminal device selects the preamble with the lowest power as the first preamble from which it determines the power for sending the PUSCH. The method of the first aspect further comprises receiving, by the terminal device, a random access response sent by the network device, wherein the indication information is carried in the random access response, and random access-radio network temporary identifiers (RA-RNTIs) corresponding to at least two random access preambles in the plurality of random access preambles are same; wherein determining, by the terminal device, a power for sending a PUSCH according to a transmission power of a first random access preamble in the at least one random access preamble, comprises determining the power for sending the PUSCH according to the transmission power of the first random access preamble and a preset corresponding relationship between a transmission power of a random access preamble and a power of the PUSCH. In a second aspect, there is provided a random access method, including sending, by a network device, indication information to a terminal device, wherein the indication information is used for indicating at least one random access preamble in random access preambles detected by the network device, the random access preambles detected by the network devi