# PROFEE: A Probabilistic-Feedback Based Speed Rate Adaption for IEEE 802.11 bc
###### Abstract  
WiFi is a widely used wireless technology for data transmission. WiFi can also play a crucial role in simultaneously broadcasting content to multiple devices in multimedia transmission for venues such as classrooms, heaters, and stadiums, etc. Broadcasting allows for the efficient dissemination of information to all devices connected to the network, and it becomes crucial to ensure that the WiFi network has sufficient capacity to transmit broadcast multimedia content without interruptions or delays. However, using WiFi for broadcasting presents challenges that can impact user experience, specifically the difficulty of obtaining real-time feedback from potentially hundreds or thousands of users due to potential collisions of feedback messages. This work focuses on providing accurate feedback to the Access Point about the percentage of users not receiving broadcast traffic correctly so it can adjust its Modulation and Coding Scheme (MCS) while transmitting broadcast multimedia content to many users. The proposed method is comprised of two sequential algorithms. In order to reduce the probability of a collision after transmitting each message, an algorithm searches for the best probability value for users to transmit ACK/NACK messages, depending on whether messages are received correctly or not. This feedback allows the Access Point to estimate the number of STAs correctly/incorrectly receiving the messages being transmitted. A second algorithm uses this estimation so the Access Point can select the best MCS while maintaining the percentage of users not receiving broadcast content correctly within acceptable margins, thus providing users with the best possible content quality. We implemented the proposed method in the ns-3 simulator, and the results show it yields quick, reliable feedback to the Access Point that was then able to adjust to the best possible MCS in only a few seconds, regardless of the user density and dimensions of the scenario. 802.11 bc; wireless multimedia; rate adaption; broadcastVarious requirements have been placed on this new standard, described in [1]. First, the new 802.11 bc must comply with the Project Authorization Request (PAR) and Criteria for Standards Development (CSD) established for it. It should provide authenticity protection for broadcast data messages. It must support modes of operation in a BSS (Basic Service System) infrastructure with association between the transmitter and receivers and cases without association. It must also include a mechanism to facilitate efficient diffusion in terms of energy consumption. Finally, it should provide a mechanism for the discovery of 11 bc-compatible STAs and for the discovery of STAs that consume a specific broadcasting service. The single most problematic aspect of WiFi broadcast is the inability of the Access Point (AP) to obtain real-time feedback from stations (STAs), as it becomes troublesome for users to send ACKs after receiving each message without causing a collision. Developing efficient and scalable feedback mechanisms from STAs in WiFi broadcast applications has historically been addressed through four distinct approaches. Each of these approaches offers advantages but also entails inevitable trade-offs. The first approach tries to decrease the number of transmitted feedback messages [2; 3] but requires previous management among STAs (along with its signaling costs) so they all agree on which STAs can send feedback. The second approach makes the feedback messages collision-resistant [4; 5]. However, implementing the scheme under this approach requires complex coding or sending the messages through a different communication channel. The third approach decreases the size of the feedback messages [6]; nevertheless, the problem remains as the number of STAs increases, even for small feedback messages. Finally, some approaches transmit broadcast messages into unicast [7; 8; 9; 10].