Communication method and communication apparatus
A terminal device receives a reference signal from a first cell, where time domain resources occupied by the reference signal are fewer than total time domain resources occupied by a synchronization signal block (SSB) of the first cell and system information (SI) of the first cell. The terminal device sends a wake-up signal (WUS) to the first cell, where the wake-up signal is used to wake up the first cell to send the SSB and/or the SI. In this way, the terminal device can quickly access the cell, to reduce a delay of accessing the cell by the terminal device, and improve communication performance. The time domain resources occupied by the reference signal are fewer than the total time domain resources occupied by the SSB of the first cell and the SI of the first cell.
1 . A method, comprising:
receiving, by a terminal device, a reference signal from a first cell, wherein time domain resources occupied by the reference signal are fewer than total time domain resources occupied by a synchronization signal block (SSB) of the first cell and system information (SI) of the first cell; and
sending, by the terminal device, a wake-up signal (WUS) to the first cell, wherein the wake-up signal is used to wake up the first cell to send the SSB and/or the SI.
2 . The method according to claim 1 , further comprising:
determining, by the terminal device, the first cell based on the reference signal.
3 . The method according to claim 1 , wherein the reference signal comprises at least one of:
an identifier of the first cell, a number of a system frame in which the reference signal is located, a half-frame indication, an index of the reference signal, a beam index of the reference signal, a time-frequency resource for sending the wake-up signal, a feature parameter of a pseudo-random sequence used by the wake-up signal, a condition for sending the wake-up signal by the terminal device, a paging indication, or a system information number.
4 . The method according to claim 1 , wherein sending, by the terminal device, the wake-up signal to the first cell comprises:
sending, by the terminal device, the wake-up signal to the first cell when a first condition is met, wherein
the first condition comprises at least one of: the terminal device determines to camp on or access the first cell; received power of the reference signal is greater than a threshold; the reference signal is a reference signal with maximum received power among reference signals that are received by the terminal device and that respectively correspond to one or more cells; the reference signal comprises a paging indication; or a system information number comprised in the reference signal changes.
5 . The method according to claim 1 , wherein the reference signal comprises the time-frequency resource for sending the wake-up signal and the feature parameter of the pseudo-random sequence used by the wake-up signal, and the method further comprises:
generating, by the terminal device, the wake-up signal based on the feature parameter of the pseudo-random sequence used by the wake-up signal; and
sending, by the terminal device, the wake-up signal to the first cell comprises:
sending, by the terminal device, the wake-up signal to the first cell on the time-frequency resource for sending.
6 . The method according to claim 1 , wherein the wake-up signal comprises a preamble for waking up the first cell to send the SSB and/or the SI.
7 . A method, comprising:
sending, by an access network device, a reference signal to a terminal device, wherein the access network device is an access network device to which a first cell belongs, and time domain resources occupied by the reference signal are fewer than total time domain resources occupied by a synchronization signal block (SSB) of the first cell and system information (SI) of the first cell; and
receiving, by the access network device, a wake-up signal (WUS) from the terminal device, wherein the wake-up signal is used to wake up the access network device to send the SSB and/or the SI in the first cell.
8 . The method according to claim 7 , wherein the reference signal comprises at least one of:
an identifier of the first cell, a number of a system frame in which the reference signal is located, a half-frame indication, an index of the reference signal, a beam index of the reference signal, a time-frequency resource for sending the wake-up signal, a feature parameter of a pseudo-random sequence used by the wake-up signal, a condition for sending the wake-up signal by the terminal device, a paging indication, or a system information number.
9 . The method according to claim 7 , further comprising:
sending, by the access network device, the SSB and/or the SI to the terminal device.
10 . The method according to claim 9 , further comprising:
determining, by the access network device, whether to enable broadcasting of the SSB and/or the SI in the first cell; and
if the access network device determines to enable broadcasting of the SSB and/or the SI in the first cell, performing, by the access network device, the step of sending, by the access network device, the SSB and/or the SI to the terminal device.
11 . The method according to claim 10 , wherein determining, by the access network device, whether to enable broadcasting of the SSB and/or the SI in the first cell comprises:
determining, by the access network device based on first information, whether to enable broadcasting of the SSB and/or the SI in the first cell, wherein
the first information comprises at least one of: load of the first cell, load of a neighboring cell of the first cell, or received power of the reference signal.
12 . The method according to claim 7 , wherein the reference signal comprises the time-frequency resource for sending the wake-up signal and the feature parameter of the pseudo-random sequence used by the wake-up signal, and the method further comprises:
receiving, by the access network device, the wake-up signal from the terminal device on the time-frequency resource for sending; and
determining, by the access network device, the wake-up signal based on the feature parameter of the pseudo-random sequence used by the wake-up signal.
13 . The method according to claim 7 , wherein the wake-up signal comprises a preamble for waking up the first cell to send the SSB and/or the SI.
14 . An apparatus, comprising:
a processor; and
a non-transitory computer-readable medium including computer-executable instructions that, when executed by the processor, cause the apparatus to carry out a method including:
receiving, by a terminal device, a reference signal from a first cell, wherein time domain resources occupied by the reference signal are fewer than total time domain resources occupied by a synchronization signal block (SSB) of the first cell and system information (SI) of the first cell; and
sending, by the terminal device, a wake-up signal (WUS) to the first cell, wherein the wake-up signal is used to wake up the first cell to send the SSB and/or the SI.
15 . The apparatus according to claim 14 , wherein the method further comprises:
determining, by the terminal device, the first cell based on the reference signal.
16 . The apparatus according to claim 14 , wherein the reference signal comprises at least one of:
an identifier of the first cell, a number of a system frame in which the reference signal is located, a half-frame indication, an index of the reference signal, a beam index of the reference signal, a time-frequency resource for sending the wake-up signal, a feature parameter of a pseudo-random sequence used by the wake-up signal, or a condition for sending the wake-up signal by the terminal device.
17 . The apparatus according to claim 14 ,
wherein sending, by the terminal device, the wake-up signal to the first cell comprises:
sending, by the terminal device, the wake-up signal to the first cell when a first condition is met, wherein
the first condition comprises at least one of: the terminal device determines to camp on or access the first cell; received power of the reference signal is greater than a threshold; the reference signal is a reference signal with maximum received power among reference signals that are received by the terminal device and that respectively correspond to one or more cells; the reference signal comprises a paging indication; or a system information number comprised in the reference signal changes.
18 . The apparatus according to claim 14 ,
wherein the reference signal comprises the time-frequency resource for sending the wake-up signal and the feature parameter of the pseudo-random sequence used by the wake-up signal, and the method further comprises:
generating, by the terminal device, the wake-up signal based on the feature parameter of the pseudo-random sequence used by the wake-up signal; and
sending, by the terminal device, the wake-up signal to the first cell comprises:
sending, by the terminal device, the wake-up signal to the first cell on the time-frequency resource for sending.
19 . The apparatus according to claim 14 , wherein the wake-up signal comprises a preamble for waking up the first cell to send the SSB and/or the SI.