# Estimating PQoS of Video Conferencing on Wi-Fi Networks Using Machine Learning
## 4 Discussion
In a wireless network, CRC errors can occur due to packet collision in environments with dense populations of wireless devices, overlapping APs, and/or multipath or non-802.11 interference on their frequency bands. Moreover, these parameters can indicate interference in the communication medium. The rxrtsucast represents the number of unicast request-to-send (RTS) frames targeted to the AP. The request to send/clear to send (RTS/CTS) frames are used to reserve the wireless medium for uninterrupted data transmission with a 2347 byte threshold, which is often used to avoid collisions caused by hidden nodes in the wireless network. Generally, the problem of hidden nodes is greater on busy networks in buildings composed of reflecting materials, where data transmissions are more often corrupted by unintended collisions [21]. Since RTS frames are transmitted at the slowest speeds, transmitting RTS/CTS frames can reduce network throughput. Therefore, a high number of received RTS frames indicates that the network is busy and that the probability of collisions is high. In addition, ISPs can increase the number of APs along with reducing transmitting power and cell size to improve the quality of busy wireless networks. The rxprobereq represents the number of probe request frames received by the AP. Clients transmit probe request frames on every channel that they support to scan the air for 802.11 networks. An excessive number of probe request frames indicates that clients have disconnected from the AP too frequently, which may be caused by interference or low signal strength. Regarding client-side features in the REPTree model, the network time counter represents the number of seconds that a client was associated with as well as authenticated and authorized to the wireless network. Moreover, the network time counter, along with the number of probe requests, can be used to identify how often the client was disconnected from the network, which may have been caused by poor channel conditions. The client-side transmit retries counter (txPktsRetries) shows that the AP retransmitted packets to a client. This counter increases for each packet that the AP retransmits, and therefore a sharp increase in the number of txPktsRetries indicates poor channel conditions. However, the txPktsRetries counter indicates only the number of retransmissions, so other parameters should be used to find the probable cause of retransmissions. Figure 6 illustrates a sharp increase in the number of retransmitted packets, which indicates poor communication channel quality and is classified as MOS = 1 during video conferencing. The transmit failures (txFailures) in the model indicate that frames were discarded when the maximum number of retransmission retries was exceeded due to either short or long retry limits. The number and duration of failed transmissions can indicate whether a poor channel condition was transient or long-lasting. In addition, comparing received errors with failed transmissions can distinguish between situations where the end-to-end communication channel is poor and those where only one side is experiencing issues transmitting data. In addition, APs collect the total number of transmitted frames that failed in the access categories introduced by IEEE QoS amendments. Changes in this parameter, along with client-side failed transmissions, can indicate whether the AP failed to transmit to a specific client or generally failed to transmit data due to interference. This study achieved promising results in estimating the PQoS of video conferencing over Wi-Fi networks. The produced ML model can be executed on off-the-shelf Wi-Fi APs to monitor the quality of wireless connectivity at customer premises to ensure predictable, measurable wireless quality. Our novel approach avoids sending raw data to the cloud infrastructure of ISPs by classifying wireless quality on the edge of networks in the form of edge computing.