The throughput of an isolated wireless link between a pair of nodes depends on various factors such as the distance between them, their transmit powers, characteristics of the environment they are in (path loss, fading, ambient noise), and the data rate used for transmission.
Because of the broadcast nature of the wireless medium, the achievable throughput of a wireless link in an IEEE 802.11 multihop wireless network is dependent not only on the operational data rate of the link, but also on the nodes that use the same radio channel as the link and are within the hearing range of the two endpoints of the link, and their level of activity.
As per the IEEE 802.11 Medium Access Control Protocol’s Distributed Coordination Function (DCF)