  A new backward compatible WiFi amendment is under development by the IEEE bd
Task Group towards the so-called IEEE 802.11bd, which includes the possibility
to transmit up to three repetitions of the same packet. This feature increases
time diversity and enables the use of maximum ratio combining (MRC) at the
receiver to improve the probability of correct decoding. In this work, we first
investigate the packet repetition feature and analyze how it looses its
efficacy increasing the traffic as an higher number of transmissions may
augment the channel load and collision probability. Then, we propose two
strategies for adaptively selecting the number of transmissions leveraging on
an adapted version of the channel busy ratio (CBR), which is measured at the
transmitter and is an indicator of the channel load. The proposed strategies
are validated through network-level simulations that account for both the
acquisition and decoding processes. Results show that the proposed strategies
ensure that devices use optimal settings under variable traffic conditions.
