Cloud control to optimize real-time video transmission in dense IEEE 802.11aa/ax networks

Inter- and intra-cell interferences significantly degrade the quality of service (QoS) in dense Wi-Fi networks. A promising way to cope with the interference is the use of centralized coordination of various stations in a Wi-Fi infrastructure network. Specifically, to avoid interference from the neighbors, the interfering stations need to execute orthogonal channel access and transmit data in non-overlapping channel times. The paper studies how to use the the features of IEEE 802.11aa/ax in order to guarantee reliable real-time video communication in dense Wi-Fi networks. In particular, IEEE 802.11aa allows an access point to reserve in advance a periodic sequence of channel times during which the data can be transmitted only between two devices, while the neighboring devices should keep silent. IEEE 802.11ax introduces trigger-based multi-user access, which can be done in a periodic way. To optimize and synchronize schedules of various access points a cloud controller can be used. Because of the random nature of the wireless channel and dynamic bit rate of a video stream, the amount of needed channel time varies. The paper proposes an approach on how to jointly use the reserved channel times and the idle channel times in order to satisfy QoS requirements of real-time video transmissions. A mathematical model is developed which can be used at the cloud controller to optimize the performance of the designed approach in terms of satisfying QoS requirements with the minimal channel time consumption. The high efficiency of the designed approach is evaluated with the real video traces.