Wireless communication system

1. A wireless communication system of a tree structure comprising an end device that is located on a lowest level, a master device, located at a higher level than the end device, and that has a master/slave connection relationship with the end device, and a destination device that ultimately receives a message that is sent from the end device through the master device,

wherein the end device comprises:

a message transmitter transmitting, to the master device, a message that includes at least its own communication address as a transmission origin address, a communication address of a destination device as an address for the ultimate transmission destination, proxy communication request information as information for whether or not to perform proxy communication, and route search request information as information for whether or not to perform a route search;

wherein the master device comprises:

a message receiver receiving a message from the end device;

a round-trip (outbound and inbound) route search executing device executing a search for a round-trip route from that device to the destination device when the route search request information included in the message received from the end device indicates that a route search is to be executed; and

a proxy message transmitting and processing device storing, as proxy information when the proxy communication request information included in the message received from the end device indicates that proxy communication is to be performed, a pair of the transmission origin address and the ultimate transmission destination address that is included in the message, and also for overwriting the address of the transmission origin included in the message with its own communication address, to be a proxy message to the destination device, and then sending this proxy message to the device of the next transmission destination following the outbound route that has been searched.

2. The wireless communication system as set forth in claim 1 , wherein the destination device comprises:

a message return transmitting and processing device sending back a message including, at least, its own communication address as a return transmission origin address and the communication address of the master device as the ultimate return transmission destination address, to the device of the next transmission destination following the inbound route that has been searched by the master device, when a proxy message has been received from the master device; and

the master device comprises:

a proxy information checker checking whether or not there exists, as an ultimate transmission destination address in the proxy information, an address matching a return transmission origin address included in the message when a message has been received from the destination device;

a proxy communication resolving device reading out the transmission origin address in the proxy information that has been stored in a pair with the matching address, when it has been confirmed by the proxy information checking means that there exists, in the proxy information, a matching address, and for overwriting, with the transmission origin address that has been read out, the return transmission destination address included in the message from the destination device, and also deleting the proxy information used at that time; and

a message return transmitter sending back, to the end device, the message from the destination device that has been overwritten by the proxy communication resolving device.

3. The wireless communication system as set forth in claim 1 , wherein:

no exchange of their own messages is performed between the master device and the destination device.