A data transmission method for packet aggregation, comprising: determining, by an access point, AP, an aggregation relay node in a service area, for aggregating multiple Medium Access Control, MAC, frames that are sent by multiple data nodes to form an aggregated MAC frame; and receiving, by the AP, the aggregated MAC frame sent by the aggregation relay node, wherein the aggregated MAC frame is formed by the multiple MAC frames that are sent by the multiple data nodes and is aggregated by the aggregation relay node; wherein the determining, in a service area, an aggregation relay node for aggregating data comprises: determining, according to a preset condition, that a part of relay nodes in all relay nodes in the service area are used as the aggregation relay node; dividing the service area into a plurality of groups according to a preset grouping rule, wherein each group in the plurality of groups comprises a plurality relay nodes and a plurality data nodes; sending a beacon to the plurality of relay nodes in one specific group in the plurality of groups; receiving acknowledgement frames for the beacon, wherein the acknowledgement frames are sent by the plurality of relay nodes in each group, and the acknowledgement frames carry received signal strength information of the plurality of relay nodes in the one specific group; and selecting, according to the received signal strength information of the plurality of relay nodes in the one specific group that the acknowledgement frames, one or more relay nodes with maximal received signal strength as an aggregation relay node in the one specific group. determining, by an access point, AP, an aggregation relay node in a service area, for aggregating multiple Medium Access Control, MAC, frames that are sent by multiple data nodes to form an aggregated MAC frame; and receiving, by the AP, the aggregated MAC frame sent by the aggregation relay node, wherein the aggregated MAC frame is formed by the multiple MAC frames that are sent by the multiple data nodes and is aggregated by the aggregation relay node; wherein the determining, in a service area, an aggregation relay node for aggregating data comprises: determining, according to a preset condition, that a part of relay nodes in all relay nodes in the service area are used as the aggregation relay node; dividing the service area into a plurality of groups according to a preset grouping rule, wherein each group in the plurality of groups comprises a plurality relay nodes and a plurality data nodes; sending a beacon to the plurality of relay nodes in one specific group in the plurality of groups; receiving acknowledgement frames for the beacon, wherein the acknowledgement frames are sent by the plurality of relay nodes in each group, and the acknowledgement frames carry received signal strength information of the plurality of relay nodes in the one specific group; and selecting, according to the received signal strength information of the plurality of relay nodes in the one specific group that the acknowledgement frames, one or more relay nodes with maximal received signal strength as an aggregation relay node in the one specific group. determining, according to a preset condition, that a part of relay nodes in all relay nodes in the service area are used as the aggregation relay node; dividing the service area into a plurality of groups according to a preset grouping rule, wherein each group in the plurality of groups comprises a plurality relay nodes and a plurality data nodes; sending a beacon to the plurality of relay nodes in one specific group in the plurality of groups; receiving acknowledgement frames for the beacon, wherein the acknowledgement frames are sent by the plurality of relay nodes in each group, and the acknowledgement frames carry received signal strength information of the plurality of relay nodes in the one specific group; and selecting, according to the received signal strength information of the plurality of relay nodes in the one specific group that the acknowledgement frames, one or more relay nodes with maximal received signal strength as an aggregation relay node in the one specific group.