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For each BI, the LL-Gw that implements QBAIoT sends a beacon frame containing the information about the BO and SO values as well as the values for the first and last slot of each QoS CAP. These values are used by the IoT objects in the sensing layer to determine how long they are allowed to be in contention to access the channel. The QBAIoT gateway chooses an initial configuration for the superframe according to the number and types of QoS classes that exist in its environment. Following the dispatch of a beacon frame, the QBAIoT gateway begins to receive data from different objects during the corresponding QoS CAPs. The schema for the QBAIoT algorithm deployed for the gateway is illustrated in Figure 1.5.

A QBAIoT gateway also has self-management functionalities. Indeed, a self-configuring function allows the gateway to adapt the configuration of the different QoS CAPs based on the existing number of QoS classes in its environment. This function also makes it possible to apply a reconfiguration of these QoS-based contention periods following changes made at the iSLA level regarding the environment of this gateway. On the other hand, a self-optimizing function performed by QBAIoT overcomes the problem of unused slots by IoT objects in a QoS CAP. This function is provided by a slot reallocation mechanism covering the entire superframe. The two functions, self-configuring and self-optimizing, make it possible to improve the QBAIoT performance in an IoT environment.

Figure 1.5. Algorithm for the QBAIoT access method at the gateway level