A physical layer collision avoidance device (10-1N), comprising: a communication circuit , used to receive a first synchronization packet (PA0-PAN), wherein the first synchronization packet (PAO-PAN) comprises first identification information (IDO-IDN) of a first physical layer collision avoidance device (10-1N); a controller , coupled to the communication circuit and maintaining an identification information table and a device count, wherein the controller is configured to: generate a random number as identification information (IDO-IDN) of the physical layer collision avoidance device (10-1N); determine a first comparison result between the identification information (IDO-IDN) of the physical layer collision avoidance device (10-1N) and the first identification information (IDO-IDN) of the first physical layer collision avoidance device (10-1N); update the identification information table and the device count based on the first comparison result; control the communication circuit to send a synchronization packet (PAO-PAN) corresponding to the physical layer collision avoidance device (10-1N) based on the first comparison result; and determine a node identity for the physical layer collision avoidance device (10-1N) in a physical layer collision avoidance network based on the identification information table. a communication circuit , used to receive a first synchronization packet (PA0-PAN), wherein the first synchronization packet (PAO-PAN) comprises first identification information (IDO-IDN) of a first physical layer collision avoidance device (10-1N); a controller , coupled to the communication circuit and maintaining an identification information table and a device count, wherein the controller is configured to: generate a random number as identification information (IDO-IDN) of the physical layer collision avoidance device (10-1N); determine a first comparison result between the identification information (IDO-IDN) of the physical layer collision avoidance device (10-1N) and the first identification information (IDO-IDN) of the first physical layer collision avoidance device (10-1N); update the identification information table and the device count based on the first comparison result; control the communication circuit to send a synchronization packet (PAO-PAN) corresponding to the physical layer collision avoidance device (10-1N) based on the first comparison result; and determine a node identity for the physical layer collision avoidance device (10-1N) in a physical layer collision avoidance network based on the identification information table. generate a random number as identification information (IDO-IDN) of the physical layer collision avoidance device (10-1N); determine a first comparison result between the identification information (IDO-IDN) of the physical layer collision avoidance device (10-1N) and the first identification information (IDO-IDN) of the first physical layer collision avoidance device (10-1N); update the identification information table and the device count based on the first comparison result; control the communication circuit to send a synchronization packet (PAO-PAN) corresponding to the physical layer collision avoidance device (10-1N) based on the first comparison result; and determine a node identity for the physical layer collision avoidance device (10-1N) in a physical layer collision avoidance network based on the identification information table. <EOS>