# US 2019/0357271 A1 · Random access preamble sending method and apparatus > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2019/0357271 A1 - Document ID: US20190357271A1 - Status: Published application - Kind: A1 - Application number: 16/530,649 - Filed: 2019-08-02 - Published: 2019-11-21 - Earliest claimed: 2017-02-03 - Assignees: Huawei Technologies Co., Ltd. - Applicants: Huawei Technologies Co., Ltd. - Inventors: Mao YAN; Lei CHEN - Web page: https://patentgrep.com/patent/US20190357271A1 ## CPC - H04L 41/0654: using network fault recovery (ring fault isolation or reconfiguration in loop networks without recovery actions by a network management system H04L12/437) - H04W 72/56: based on priority criteria - H04W 74/0833: Random access procedures, e.g. with 4-step access - H04W 74/006: {in the downlink, i.e. towards the terminal} - H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M) - H04W: WIRELESS COMMUNICATION NETWORKS (broadcast communication H04H; communication systems using wireless links for non-selective communication, e.g. wireless extensions H04M1/72) ## Abstract Embodiments of the present invention disclose a random access preamble sending method and an apparatus. The method includes: sending, by user equipment, a first random access preamble to a network device, where the first random access preamble is used by the user equipment to access the network device; and when the user equipment fails in accessing the network device by using the first random access preamble, sending at least one second random access preamble to the network device, where access characteristic information of each second random access preamble is different from that of the first random access preamble, the access characteristic information includes at least one of a time length, a transmit beam, and a random access resource, and the at least one second random access preamble is used by the user equipment to access the network device. In the embodiments of the present invention, a problem of a random access failure in a future wireless communications network caused by the fact that a random access preamble does not arrive at the network device is resolved, thereby increasing a probability that the random access preamble arrives at the network device and increasing a random access success rate. ## Claims ### Claim 1 A random access preamble sending method, comprising: sending, by user equipment, a first random access preamble to a network device, wherein the first random access preamble is used by the user equipment to access the network device; and when the user equipment fails in accessing the network device by using the first random access preamble, sending, by the user equipment, at least one second random access preamble to the network device, wherein access characteristic information of each of the at least one second random access preamble is different from that of the first random access preamble, the access characteristic information comprises at least one of a time length, a transmit beam, and a random access resource, and the at least one second random access preamble is used by the user equipment to access the network device. ### Claim 2 (depends on 1) The method according to claim 1, wherein access characteristic information of any two of the at least one second random access preamble is different. ### Claim 3 (depends on 1) The method according to claim 1, wherein if a time length of each second random access preamble is different from that of the first random access preamble, the time length of each second random access preamble is greater than that of the first random access preamble. ### Claim 4 (depends on 1) The method according to claim 1, wherein if a transmit beam of each second random access preamble is different from that of the first random access preamble, a random access resource of each second random access preamble is the same as or different from that of the first random access preamble. ### Claim 5 (depends on 1) The method according to claim 1, wherein if a random access resource of each second random access preamble is different from that of the first random access preamble, a transmit beam of each second random access preamble is the same as or different from that of the first random access preamble. ### Claim 6 (depends on 1) The method according to claim 1, wherein a transmit power of each second random access preamble is the same as or different from that of the first random access preamble, and transmit powers of any two of the at least one second random access preamble are the same or different. ### Claim 7 (depends on 1) The method according to claim 1, wherein the sending, by the user equipment, at least one second random access preamble to the network device comprises: sending, by the user equipment, the at least one second random access preamble to the network device based on priorities of the time length, the transmit power, the transmit beam, and the random access resource. ### Claim 8 User equipment, wherein the user equipment comprises a processor and a transceiver; the transceiver is configured to send a first random access preamble to a network device, wherein the first random access preamble is used by the user equipment to access the network device; and the transceiver is further configured to: when the user equipment fails in accessing the network device by using the first random access preamble, send at least one second random access preamble to the network device, wherein access characteristic information of each of the at least one second random access preamble is different from that of the first random access preamble, the access characteristic information comprises at least one of a time length, a transmit beam, and a random access resource, and the at least one second random access preamble is used by the user equipment to access the network device. ### Claim 9 (depends on 8) The user equipment according to claim 8, wherein access characteristic information of any two of the at least one second random access preamble is different. ### Claim 10 (depends on 8) The user equipment according to claim 8, wherein if a time length of each second random access preamble is different from that of the first random access preamble, the time length of each second random access preamble is greater than that of the first random access preamble. ### Claim 11 (depends on 8) The user equipment according to claim 8, wherein if a transmit beam of each second random access preamble is different from that of the first random access preamble, a random access resource of each second random access preamble is the same as or different from that of the first random access preamble. ### Claim 12 (depends on 8) The user equipment according to claim 8, wherein if a random access resource of each second random access preamble is different from that of the first random access preamble, a transmit beam of each second random access preamble is the same as or different from that of the first random access preamble. ### Claim 13 (depends on 8) The user equipment according to claim 8, wherein a transmit power of each second random access preamble is the same as or different from that of the first random access preamble, and transmit powers of any two of the at least one second random access preamble are the same or different. ### Claim 14 (depends on 8) The user equipment according to claim 8, wherein the transceiver is specifically configured to send the at least one second random access preamble to the network device based on priorities of the time length, the transmit power, the transmit beam, and the random access resource.