Introduction
Bluetooth® Periodic Advertising with Responses (PAwR) enables a single broadcasting device (PAwR Advertiser, e.g., a gateway) to communicate with a large number of scanning devices (PAwR Scanners, e.g., sensors, electronic shelf labels). The broadcasting device transmits periodic advertising packets, and scanning devices are permitted to send responses within specifically allocated time windows.
PAwR establishes an ordered, efficient, and scalable one-to-many bidirectional communication scheme. It is designed to support connectivity for massive numbers of devices while preventing packet collisions through scheduled timing.
Principle
Roles
Two roles are defined for PAwR: the PAwR Advertiser and the PAwR Scanner.
Timing
The following diagram illustrates the PAwR timing structure. A periodic advertising with responses event is divided into multiple subevents. Each subevent contains a response slot delay interval followed by one or more response slots. The PAwR Advertiser transmits advertising packets in every subevent. A PAwR Scanner may synchronize to all or a specific subset of these subevents and will only listen for packets in its synchronized subevents. Upon receiving a packet, a PAwR Scanner may send a response to the PAwR Advertiser within a designated response slot of any subevent.

Communication Topology
The following diagram illustrates the communication topology established by PAwR, which is a centralized, one-to-many star topology. The Subevent mechanism can be used to logically group PAwR Scanners. For example, PAwR Scanners with different functions or located in distinct areas can be assigned to the same subevent for management. Furthermore, a PAwR Scanner may synchronize to multiple subevents to receive the corresponding advertisements. This allows PAwR Scanners with overlapping functionalities to receive information from multiple groups. PAwR Scanners transmit messages to the PAwR Advertiser in the response slots. PAwR Scanners do not receive messages from other PAwR Scanners. Within this topology, all timing parameters for communication are defined and configured by the PAwR Advertiser. The entire topology's communication relies on the PAwR Advertiser; therefore, a failure of a single PAwR Scanner has limited impact on the overall communication, whereas a failure of the PAwR Advertiser will halt all communication.

Within the PAwR mechanism:
The following table compares PAwR with other Bluetooth® communication mechanisms:

Application Scenarios



苏公网安备32059002006558号
苏ICP备10062199号-8