A data communication apparatus, comprising: a memory, configured to store computer executable program code, wherein the program code comprises an instruction; and a processor, configured to execute the instruction, to cause the data communication apparatus to perform the following operations: receiving, a preset frame from a target relay, wherein the target relay and the data communication apparatus belong to a first basic service set, BSS; receiving a physical layer protocol data unit, PPDU, wherein the PPDU comprises a BSS identifier; if the BSS identifier in the PPDU is different from a first BSS identifier and the BSS identifier in the PPDU is the same as a second BSS identifier, determining (S201) whether the PPDU meets a preset spatial reuse condition, wherein the first BSS identifier is an identifier of the first BSS, wherein the preset frame comprises the second BSS identifier of an extended BSS to which the target relay belongs; and if the PPDU meets the preset spatial reuse condition, contending for (S202) a channel, and communicating with a station other than the target relay in the first BSS; wherein the data communication apparatus is a root access point, AP, and wherein the root AP is associated with a plurality of relays, and each of the plurality of relays is associated with one or more stations. a memory, configured to store computer executable program code, wherein the program code comprises an instruction; and a processor, configured to execute the instruction, to cause the data communication apparatus to perform the following operations: receiving, a preset frame from a target relay, wherein the target relay and the data communication apparatus belong to a first basic service set, BSS; receiving a physical layer protocol data unit, PPDU, wherein the PPDU comprises a BSS identifier; if the BSS identifier in the PPDU is different from a first BSS identifier and the BSS identifier in the PPDU is the same as a second BSS identifier, determining (S201) whether the PPDU meets a preset spatial reuse condition, wherein the first BSS identifier is an identifier of the first BSS, wherein the preset frame comprises the second BSS identifier of an extended BSS to which the target relay belongs; and if the PPDU meets the preset spatial reuse condition, contending for (S202) a channel, and communicating with a station other than the target relay in the first BSS; wherein the data communication apparatus is a root access point, AP, and wherein the root AP is associated with a plurality of relays, and each of the plurality of relays is associated with one or more stations. receiving, a preset frame from a target relay, wherein the target relay and the data communication apparatus belong to a first basic service set, BSS; receiving a physical layer protocol data unit, PPDU, wherein the PPDU comprises a BSS identifier; if the BSS identifier in the PPDU is different from a first BSS identifier and the BSS identifier in the PPDU is the same as a second BSS identifier, determining (S201) whether the PPDU meets a preset spatial reuse condition, wherein the first BSS identifier is an identifier of the first BSS, wherein the preset frame comprises the second BSS identifier of an extended BSS to which the target relay belongs; and if the PPDU meets the preset spatial reuse condition, contending for (S202) a channel, and communicating with a station other than the target relay in the first BSS; wherein the data communication apparatus is a root access point, AP, and wherein the root AP is associated with a plurality of relays, and each of the plurality of relays is associated with one or more stations. <EOS>