Pairing Procedure
The Pairing Module is used by applications to dynamically assign addresses to new nodes wanting to join a network. This module runs at the application level, so it uses the SWC API to create a dedicated schedule with its own connections.
Pairing Phases
The Pairing Procedure will pass through three phases: the Authentication phase, the Identification phase and the Addressing phase.
Authentication Phase
The Authentication phase is essential for verifying the compatibility of the unpaired devices. It involves the verification of the devices’ Application Code. If the Application Codes do not match, the pairing procedure is aborted since the node’s response field for authentication_action will reflect a failure. This mismatch indicates an incompatibility between the devices. On the other hand, if the Application Codes match, the next step in the pairing process is initiated, signifying that both devices and the application they run are compatible.
This phase helps to prevent the pairing of two devices that possess pairing capabilities but lack compatibility. For instance, it ensures that a mouse device cannot pair with a headset device, as such a pairing would be functionally inappropriate.
Identification Phase
The Identification phase involves the Node transmitting its device role and unique identifier number to the Coordinator. The Coordinator generates the Node address with the received unique identifier number. It then stores the Node’s device role, the generated Node address and the unique identifier number in its Pairing Discovery List. If the device role was already present in the Discovery List, it will be overwritten by the new Node address and unique identifier number. The Coordinator then proceeds to initiate the Addressing States.
Addressing phase
The Addressing phase involves the Coordinator sending to the Node device the network PAN ID, the Coordinator address and the newly generated Node address.
During this stage, the Pairing procedure should be completed successfully.
Pairing Module Wireless Configuration
When entering the Pairing Mode, a pre-defined wireless configuration is employed, overriding any previously used wireless configurations within the application. The handling of the wireless configuration is internally managed by the Pairing Module through the SWC API.
During the Pairing Procedure, the PAN ID for both devices is fixed at 0x000, as it is the reserved address specifically designated for the Pairing Module. The coordinator is assigned the fixed address of 0x01, while the node is assigned the fixed address of 0x02. These predetermined addresses ensure proper identification and communication between the devices within the pairing framework.
The Pairing Schedule follows an alternating pattern of transmissions between the Coordinator and Node, with each device taking turns every 1 milliseconds (ms).
The wireless configuration utilizes a single channel whose frequency is automatically selected based on the detected radio model:
SR1x20 radios (SR1020/SR1120): Frequency code 195 (7.987 GHz), which corresponds to IEEE 802.15.4 UWB channel 9. The define PAIRING_SR1x20_CHANNEL_FREQUENCY is used for SR1x20 radios.
SR1x10 radios (SR1010/SR1110): Frequency code 100 (4.096 GHz). The define PAIRING_SR1x10_CHANNEL_FREQUENCY is used for SR1x10 radios.
The pairing module automatically detects the radio model during initialization and selects the appropriate frequency within the supported range of each radio family.
Figure 95: Pairing Module’s Schedule
After the completion of the Pairing Procedure, the wireless configuration will be reset. As a result, the application must reconfigure Wireless Core using the newly obtained network information.