# PROFEE: A Probabilistic-Feedback Based Speed Rate Adaption for IEEE 802.11 bc
###### Abstract
However, such solutions must be properly scaled since it may take a long time to complete the feedback transmission process, depending on the number of receivers. One aspect they all have in common is that they seek to ensure that the ACKs do not collide, thus allowing the AP to obtain feedback from the STAs. In this work, we propose a method comprised of two sequential algorithms to reduce the collision probability of the feedback messages. Our method is based on the foundation that STAs should not send feedback messages every time after receiving a message correctly/incorrectly from the AP but should transmit ACK/NACK only with a given probability. The first algorithm allows the AP to search for the best probability value for STAs to transmit ACK/NACK messages, depending on the percentage of successfully received feedback messages, collided feedback messages, or no feedback (silences). This feedback allows the AP to estimate the number of STAs receiving messages correctly/incorrectly. In the second algorithm, the AP uses this feedback to adjust the MCS to increase the data rate at the physical layer while keeping the percentage of STAs that do not receive messages correctly within a predefined range. This data rate adaption allows the AP to send better-quality content to a high proportion of the STAs in the venue, thus improving user experience. We tested the proposed method in different scenarios, varying the number of STAs and the venue's dimensions and showing that it provides fast-reliable feedback, allowing the AP to select the best MCS in only a few seconds. The method proposed in this work goes around most of the trade-offs in previous works. Our proposal does not require previous management among STAs or a different channel to send feedback messages, it has no limitations on the number of STAs, and it takes only a few seconds to complete, independent of the size and density of the scenario. An essential distinguishing feature of our proposal is its ability to monitor collisions related to feedback messages, allowing for the estimation of the number of STAs receiving messages accurately or encountering errors. There are many challenges for next-generation networks to improve communications capabilities. As stated in [11], these shortcomings include spectral efficiency, coverage, interference, security, and privacy. These concerns and those presented in this work contribute to developing next-generation networks that enable high-throughput, low-delay communications. This work makes the following specific contributions:* We propose a method that quickly finds the best probability value for STAs to send ACK/NACK messages back to the AP. This allows a fast and accurate estimation of the number of STAs receiving messages correctly/incorrectly. * Apart from using the number of ACK/NACK messages received correctly to estimate the number of STAs receiving messages correctly/incorrectly, the algorithm can also perform the very same estimation by counting the number of collisions of feedback messages and even the number of no feedback transmissions (silences) occurring after the transmission of each broadcast message. This technique allows redundancy as it provides the AP with three simultaneous and independent ways to perform the same estimation of STAs receiving messages correctly/incorrectly. * We propose a second algorithm that uses the previous estimation to allow for the AP to adapt the MCS to increase the data rate at the physical layer while maintaining the percentage of STAs that do not receive broadcast messages correctly within acceptable limits, thus allowing for higher-quality content to be sent to most STAs, improving user experience. * We implemented the complete method in ns-3 under diverse network conditions. We found that it provides quick (only a few seconds on average) and reliable (less than 5% estimation error) feedback, allowing the AP to rapidly adjust the MCS to maximize the users' experience.