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Downstream Bandwidth estimation in the absence of RTS/CTS

The total delay incurred by a data frame from an AP in the absence of $RTS/CTS$ handshake is given by: the contention and transmission delay of the data frame plus the respective $ACK$ delay.

\begin{displaymath}
T = T_{D} + T_{A}
\end{displaymath} (1)

$T_{D}$ in turn can be estimated from the beacon delay $T_{B}$, estimated as in Section 3.2, and the transmission delay of the frame2, and is given by:
\begin{displaymath}
T_{D} = T_{B} + \frac{DATA}{R}
\end{displaymath} (2)

Upon receiving the data frame, the receiver sends an $ACK$ frame after a delay of $SIFS$. $ACK$ frames are fixed in length and are typically sent at the same rate as the data frame. Hence, knowing the sender rate, $T_{A}$ can be easily determined as:

\begin{displaymath}
T_{A} = SIFS + \frac{ACK}{R}
\end{displaymath} (3)

The potential bandwidth $B$ from the $AP$ to the end-host is then given by:

\begin{displaymath}
B = \frac{DATA}{T}
\end{displaymath} (4)


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: Downstream Bandwidth estimation in : Potential Bandwidth Estimation : Beacon Delays