Читать книгу Service Level Management in Emerging Environments - Nader Mbarek - Страница 53

Figure 1.6 depicts the schema for the QBAIoT algorithm used by IoT objects, taking into account the slotted CSMA/CA method.

Figure 1.6. Algorithm for the QBAIoT access method at the loT object level

All objects in the environment of the QBAIoT gateway receive the beacon frame. Depending on the QoS class to which they belong, each object determines the QoS CAP during which it can attempt to access the shared channel. When an object generates data, it must test whether it has the right to attempt to send its traffic. If the QoS CAP corresponding to the IoT object in the superframe has not yet started, then it waits for the start of its QoS CAP and then begins competing with other objects in its QoS class to send its data according to the slotted CSMA/CA. On the other hand, if the QoS CAP of the object in the current superframe has elapsed, then it waits for the corresponding QoS CAP in the next superframe. Otherwise, the object has the right to enter into contention with the other objects of its class for access to the channel according to the slotted CSMA/CA mechanism, as its QoS CAP is in progress.