Wireless communication device, wireless communication method and program

1. A wireless communication device, comprising:

a transmission section for discretely increasing transmission power and transmitting wireless signals; and

an estimation section for estimating that, when a response signal to a previous wireless signal is not received from a first wireless communication device but a response signal to a current wireless signal is received from the first wireless communication device, the first wireless communication device exists in a hollow circular first area, which is a difference between a reachable area of the current wireless signal and a reachable area of the previous wireless signal, having the wireless communication device at a centre of a hollow part of the hollow circular first area.

2. The wireless communication device according to claim 1 , wherein

the transmission section transmits, in relation to each other, area information indicating the first area estimated by the estimation section and identification information indicating the first wireless communication device.

3. The wireless communication device according to claim 2 , wherein

in addition to the area information estimated by the estimation section and the identification information, the transmission section transmits, in relation to another wireless communication device, area information and identification information already received from the other wireless communication device.

4. The wireless communication device according to claim 3 , wherein

when second area information related with the identification information of the first wireless communication device is received from a second wireless communication device and third area information is received from a third wireless communication device, the estimation section estimates that, in case a hollow circular third area indicated by the third area information, a hollow circular second area indicated by the second area information and the first area are arranged so as to overlap with each other, a corresponding wireless communication device exists at a centre of each area.

5. The wireless communication device according to claim 4 , wherein

in case absolute location information of at least two devices among the self device, the second wireless communication device and the third wireless communication device is known, the estimation section estimates an absolute existing location of a wireless communication device other than the at least two devices based on the absolute location information of the at least two devices.

6. The wireless communication device according to claim 4 , wherein

in case absolute location information of the first wireless communication device is known, the estimation section estimates absolute existing locations of the self device, the second wireless communication device and the third wireless communication device by matching a map showing surroundings of a location indicated by the location information to an estimated location relationship among the self device, the second wireless communication device and the third wireless communication device.

7. The wireless communication device according to claim 6 , wherein the estimation section estimates the first area by substituting a frequency of the response signal into an equation relating a frequency and a distance decay.

8. A wireless communication method, comprising the steps of:

discretely increasing transmission power and transmitting wireless signals; and

estimating that, when a response signal to a previous wireless signal is not received from a first wireless communication device but a response signal to a current wireless signal is received therefrom, the first wireless communication device exists in a hollow circular first area, which is a difference between a reachable area of the current wireless signal and a reachable area of the previous wireless signal, having a wireless communication device at a centre of a hollow part of the hollow circular first area.

9. A non-transitory computer-readable storage medium storing instructions thereon, which, when executed by a computer, cause the computer to function as:

a transmission section for discretely increasing transmission power and transmitting wireless signals; and

an estimation section for estimating that, when a response signal to a previous wireless signal is not received from a first wireless communication device but a response signal to a current wireless signal is received therefrom, the first wireless communication device exists in a hollow circular first area, which is a difference between a reachable area of the current wireless signal and a reachable area of the previous wireless signal, having a wireless communication device at a centre of a hollow part of the hollow circular first area.