The MAC layer of IEEE 802.15.4 Protocol Learning

The MAC is responsible for network-based synchronization, supporting association and cancellation, security on the MAC layer, and controlling the physical channel access mechanism. The channel access mechanism mainly has the following kinds:

1. Ordered physical wireless channel access mechanism

2. Coordinator to start and maintain pan information mechanism

3. Allow the device to join or leave the pan mechanism

4. Allocation and release of the protection time slot mechanism

The GTS of the Pan coordinator based on the non-competitive mechanism to access the channel

The Pan coordinator uses the super frame structure to define the channel time of the GTS, and the frame structure is as follows:

During the cap, the send frame uses CSMA-CA to access the channel.

During the CFP, it is sent to the GTS timeslot to access the channel.

CSMA-CA avoidance algorithm based on competition mechanism

See MORE: Csma-ca Algorithm overview

Wireless sensor network has three kinds of data transmission network equipment to the Pan coordinator to send data, the coordinator to send data to the network equipment, peer-network equipment, the three kinds of data transmission. Each method is divided into Beacon network and non-Beacon network. specific as follows;

1. From Device to Coordinator

2. From the coordinator to the device

3. Point-to-point transmission

Each FFD can communicate directly with any other device, and RFD devices directly cannot communicate directly with each other.

The process of establishing a network and joining the network

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The MAC layer of IEEE 802.15.4 Protocol Learning