A mesh wireless local area network (WLAN) is a wireless network comprising two or more mesh points interconnected via wireless links. The mesh network typically serves one or more wireless stations (STAs) within the operating range of the mesh network. A mesh point is any entity within the mesh network which contains a MAC and physical layer (PHY) interface to a wireless medium and supports WLAN mesh services. An IMP is a mesh point through which data enters the mesh WLAN and an egress mesh point (EMP) is a mesh point through which data exits the mesh WLAN. Data sent by a STA is routed from the IMP to the EMP through the mesh WLAN.
IEEE 802.11 standards are one of the standards defining the wireless protocol for a mesh WLAN. Current IEEE 802.11 standards define an acknowledged mode that allows for more reliable data delivery at the lower layers. However, the current acknowledgement mechanism does not work in a mesh network since multiple hops are required over the mesh network before the data is delivered to the destination.
In a mesh WLAN, a communication between an IMP and an EMP can be required. As shown in FIG. 2, a prior art MAC frame does not contain IMP MAC address during the multi-hop transmissions. Therefore, the EMP is unable to identify and communicate with the IMP. There is no mechanism or frame format for sending an acknowledgement between the IMP and the EMP in the mesh WLAN. This seriously limits the reliability of the data delivery. Since there is no ACK mechanism between the IMP and the EMP, the IMP cannot know if the data through the mesh network has been correctly received by the EMP.