Signal sending apparatus, signal receiving apparatus, and methods

A method for signal receiving, wherein the method comprises:

• detecting, by a second network device, a first signal and a second signal that are sent by a first network device;
• and
• obtaining, by the second network device, OFDM-symbol index information, based on the first signal, that indicates an index of an OFDM symbol in which the first signal is located in a first time unit, and
• obtaining first-time-unit index information, based on the second signal, hat indicates an index of a first time unit in which the second signal is located in a second time unit, wherein the second time unit comprises at least two first time units, and each first time unit comprises at least two OFDM symbols.

An apparatus, comprising:

• a memory that includes computer instructions;
• a processor coupled to the memory, that executes the computer instructions to perform the steps of:
• detecting a first signal and a second signal that are sent by a first network device;
• and
• obtaining OFDM-symbol index information based on the first signal, and obtaining first-time-unit index information based on the second signal, wherein the OFDM-symbol index information indicates an index of an OFDM symbol in which the first signal is located in a first time unit, the first-time-unit index information indicates an index of a first time unit in which the second signal is located in a second time unit, one second time unit comprises at least two first time units, and each first time unit comprises at least two OFDM symbols.