Method of performing random access according to a coverage enhancement level, and equipment therefor
A method includes determining whether a first preset condition is met, where the first preset condition includes: a difference between a maximum transmit power allowed by the user equipment and a power of sending the random access code in a previous random access attempt process is less than or equal to a power ramping factor, and/or, the previous random access attempt process fails. The method also includes, if the first preset condition is met, sending the random access code using an enhancement mode in the current random access attempt process.
1. A method, comprising:
in response to a previous random access attempt process failing, selecting, from enhancement levels of an enhancement mode, a next enhancement level of an enhancement level used in the previous random access attempt process;
when a pre-obtained random access channel resource corresponding to the next enhancement level is available at a current moment, and in response to the current moment occurring after a start moment of the pre-obtained random access channel resource corresponding to the next enhancement level, determining whether a preset policy is met; and
when it is determined that the preset policy is met, sending, at the current moment, a random access code, wherein signal retransmission times corresponding to the next enhancement level are more than signal retransmission times corresponding to the enhancement level used in the previous random access attempt process.
2. The method according to claim 1 , wherein the preset policy comprises:
an interval between the current moment and the start moment of the pre-obtained random access channel resource corresponding to the next enhancement level is less than or equal to a first preset interval, wherein the first preset interval is fixed in a protocol.
3. The method according to claim 1 , wherein the preset policy comprises:
an interval between the current moment and an end moment of the pre-obtained random access channel resource corresponding to the next enhancement level is greater than or equal to a second preset interval, wherein the second preset interval is fixed in a protocol.
4. The method according to claim 1 , wherein after sending the random access code, the method further comprises:
using a random access response parameter pre-configured by a network device to attempt to receive a random access response message sent by the network device;
when the random access response message is not received, determining that the current random access attempt process fails; and
when the random access response message is successfully received, performing the following:
sending a scheduled transmission message to the network device using a resource that is occupied by the scheduled transmission message and that is pre-configured by the network device;
using a resource that is occupied by a contention resolution message and that is pre-configured by the network device to attempt to receive the contention resolution message indicating a random access success; and
when the contention resolution message is not received, determining that the current random access attempt process fails.
5. The method according to claim 1 , further comprising:
when a random access procedure is initiated for a first time, determining a signal transmission mode for sending the random access code, wherein the signal transmission mode is a single transmission mode or the enhancement mode;
obtaining a random access parameter that corresponds to the determined signal transmission mode and that is pre-configured by a network device; and
sending the random access code to the network device using the obtained random access parameter.
6. The method according to claim 1 , wherein the preset policy comprises:
an interval between the current moment and the start moment of the pre-obtained random access channel resource corresponding to the next enhancement level is less than or equal to a first preset interval, wherein the first preset interval is configured by a network device.
7. The method according to claim 1 , wherein the preset policy comprises:
an interval between the current moment and a end moment of the pre-obtained random access channel resource corresponding to the next enhancement level is greater than or equal to a second preset interval, wherein the second preset interval is configured by a network device.
8. The method according to claim 1 , wherein whether the preset policy is met depends on a number of possible transmission times between the current moment and an end moment of the pre-obtained random access channel resource.
9. A device, comprising:
a non-transitory memory storing instructions; and
a processor, coupled to the non-transitory memory, the processor being configured to execute the instructions to:
in response to a previous random access attempt process failing, selecting, from enhancement levels of an enhancement mode, a next enhancement level of an enhancement level used in the previous random access attempt process;
when a pre-obtained random access channel resource corresponding to the next enhancement level is available at a current moment, and in response to the current moment occurring after a start moment of the pre-obtained random access channel resource corresponding to the next enhancement level, determining whether a preset policy is met; and
when it is determined that the preset policy is met, sending, at the current moment, a random access code, wherein signal retransmission times corresponding to the next enhancement level are more than signal retransmission times corresponding to the enhancement level used in the previous random access attempt process.
10. The device according to claim 9 , wherein the preset policy comprises:
an interval between the current moment and the start moment of the pre-obtained random access channel resource corresponding to the next enhancement level is less than or equal to a first preset interval, wherein the first preset interval is fixed in a protocol.
11. The device according to claim 9 , wherein the preset policy comprises:
an interval between the current moment and an end moment of the pre-obtained random access channel resource corresponding to the next enhancement level is greater than or equal to a second preset interval, wherein the second preset interval is fixed in a protocol.
12. The device according to claim 9 , wherein the processor is further configured to execute instructions to:
use a random access response parameter pre-configured by a network device to attempt to receive a random access response message sent by the network device;
when the random access response message is not received, determine that the current random access attempt process fails; and
when the random access response message is successfully received, perform the following:
send a scheduled transmission message to the network device using a resource that is occupied by the scheduled transmission message and that is pre-configured by the network device;
use a resource that is occupied by a contention resolution message and that is pre-configured by the network device to attempt to receive the contention resolution message indicating a random access success; and
when the contention resolution message is not received, determine that the current random access attempt process fails.
13. The device according to claim 9 , wherein the processor is further configured to execute instructions to:
when a random access procedure is initiated for a first time, determine a signal transmission mode for sending the random access code, wherein the signal transmission mode is a single transmission mode or the enhancement mode;
obtain a random access parameter that corresponds to the determined signal transmission mode and that is pre-configured by a network device; and
send the random access code to the network device by using the obtained random access parameter.
14. The device according to claim 9 , wherein the preset policy comprises:
an interval between the current moment and the start moment of the pre-obtained random access channel resource corresponding to the next enhancement level is less than or equal to a first preset interval, wherein the first preset interval is configured by a network device.
15. The device according to claim 9 , wherein the preset policy comprises:
an interval between the current moment and an end moment of the pre-obtained random access channel resource corresponding to the next enhancement level is greater than or equal to a second preset interval, wherein the second preset interval is fixed in a protocol or configured by a network device.