Wireless tag communication apparatus, wireless tag communication system, and communication method for a wireless tag communication apparatus

1 . A wireless tag communication apparatus, comprising:

a wireless communication device that transmits, to wireless tags, a sequence of read commands for reading identification information of the wireless tags and receives the identification information from the wireless tags, each read command in the sequence designating a flag state of a flag set in the wireless tag, the flag state being set to one of a first state when reading is incomplete and a second state when reading is complete, each of the wireless tags returning the identification information upon receiving a corresponding one of the read commands in the sequence that designates the flag state only where the flag state corresponds to the designated flag state; and

a processor configured to

transmit, by the wireless communication device, a first read command designating the first state as the flag state and acquire, by the wireless communication device, the identification information returned from a first wireless tag of the wireless tags whose flag state is the first state,

determine, on a basis of the acquired identification information, whether or not a position of the first wireless tag has been detected,

where it is determined that the position of the first wireless tag has not been detected, transmit, by the wireless communication device, an instruction that instructs the first wireless tag to maintain the flag state to be the first state, and

where it is determined that the position of the first wireless tag has been detected, transmit, by the wireless communication device, a second read command designating the first state as the flag state without transmitting the instruction, the second read command causing the first wireless tag to rewrite the flag state to the second state.

2 . The wireless tag communication apparatus according to claim 1 , further comprising

a memory that includes a detection target storage unit that stores detected information in association with identification information of each of one or more wireless tags whose positions are to be detected, the detected information indicating whether or not the position of the corresponding wireless tag has been detected,

the processor being further configured to determine, on a basis of the detected information stored in the detection target storage unit of the memory in association with the acquired identification information, whether or not a wireless tag that has returned the identification information is a wireless tag whose position has been detected and is to be detected, and

instruct a wireless tag that is determined to be the wireless tag whose position has been detected and is to be detected to rewrite the flag state to the second state.

3 . The wireless tag communication apparatus according to claim 2 , wherein

the processor is further configured to determine, in accordance with whether or not the acquired identification information is stored in the detection target storage unit of the memory, the wireless tag that has returned the identification information is the wireless tag whose position is to be detected, and

instruct, where the wireless tag that has returned the identification information is not the wireless tag whose position is to be detected, the wireless tag that has returned the identification information to rewrite the flag state to the second state by the wireless communication device.

4 . The wireless tag communication apparatus according to claim 2 , wherein

the wireless communication device includes a state detector that detects a communication state with the wireless tag, and

the processor is further configured to

detect the position of the wireless tag on a basis of the communication state, and

set, where the position of the wireless tag is detected, the detected information stored in the detection target storage unit of the memory in association with the identification information of the wireless tag as position detected.

5 . The wireless tag communication apparatus according to claim 2 , further comprising

an interface that transmits the communication state to a detection device that detects a position of the wireless tag on a basis of the communication state with the wireless tag by the wireless communication device and receives, from the detection device, a detected notification indicating a wireless tag whose position has been detected,

the wireless communication device including a state detector that detects a communication state with the wireless tag,

the processor being further configured to set, where the interface has received the detected notification, the detected information stored in the detection target storage unit of the memory in association with the identification information of the wireless tag as position detected.

6 . The wireless tag communication apparatus according to claim 1 , wherein

the wireless tag returns identification information and then rewrites the flag state from the first state to the second state, and

the processor is further configured to

transmit, to a wireless tag determined not to be the wireless tag whose position is to be detected, a no-flag-change instruction for instructing not to rewrite the flag state to the second state, and

cause a wireless tag determined to be the wireless tag whose position is to be detected to rewrite the flag state to the second state by not transmitting the no-flag-change instruction.

7 . The wireless tag communication apparatus according to claim 2 , wherein

the memory further includes a setting storage unit that stores a setting regarding whether or not a position of the wireless tag whose position has been detected is to be corrected, and

the processor is further configured not to instruct, where the setting stored in the setting storage unit is a setting for correcting the position, the wireless tag whose position has been detected to rewrite the flag state to the second state.

8 . The wireless tag communication apparatus according to claim 1 , further comprising

a memory that includes a read data storage unit that stores identification information read from a wireless tag whose position is to be detected,

the processor being further configured to store the acquired identification information in the read data storage unit of the memory.

9 . A wireless tag communication system that includes a wireless tag communication apparatus that communicates with wireless tags and a primary apparatus that is connected to the wireless tag communication apparatus and controls the wireless tag communication apparatus, comprising:

a wireless communication device that transmits, to the wireless tags, a sequence of read commands for reading identification information of the wireless tags and receives the identification information from the wireless tags, each read command in the sequence designating a flag state of a flag set in the wireless tag, the flag state being set to one of a first state when reading is incomplete and a second state when reading is complete, each of the wireless tags returning the identification information upon receiving a corresponding one of the read commands in the sequence that designates the flag state only where the flag state corresponds to the designated flag state;

a state detector that detects a communication state with the wireless tag by the wireless communication device;

a memory that includes a detection target storage unit that stores detected information in association with identification information of each of one or more wireless tags whose positions are to be detected, the detected information indicating whether or not the position of the corresponding wireless tag has been detected; and

a processor configured to

transmit, by the wireless communication device, a first read command designating the first state as the flag state and acquire, by the wireless communication device, the identification information returned from a first wireless tag of the wireless tags whose flag state is the first state,

detect a position of the first wireless tag on a basis of the communication state detected by the state detector,

determine, on a basis of the detected information stored in the detection target storage unit of the memory in association with the acquired identification information, whether or not a position of the first wireless tag has been detected,

where it is determined that the position of the first wireless tag has not been detected, transmit, by the wireless communication device, an instruction that instructs the first wireless tag to maintain the flag state to be the first state, and

where it is determined that the position of the first wireless tag has been detected, transmit, by the wireless communication device, a second read command designating the first state as the flag state, the second read command causing the first wireless tag to rewrite the flag state to the second state.

10 . The wireless tag communication system according to claim 9 , wherein

the wireless tag communication apparatus includes the wireless communication device, the state detector, the memory, and the processor, and

the detection target storage unit of the memory stores the identification information of the wireless tag whose position is to be detected set from the primary apparatus.

11 . The wireless tag communication system according to claim 9 , wherein

the wireless tag communication apparatus includes the wireless communication device, the state detector, the memory, and the processor,

the primary apparatus detects a position of the wireless tag on a basis of the communication state, and

the detection target storage unit of the memory stores detected information in association with identification information of each of one or more wireless tags whose positions are to be detected by the primary apparatus, the detected information indicating whether or not the position of the corresponding wireless tag has been detected.

12 . A communication method for a wireless tag communication apparatus, comprising:

transmitting, to wireless tags, a sequence of read commands for reading identification information of the wireless tags by a wireless communication device, each read command in the sequence designating a flag state of a flag set in the wireless tag, the flag state being set to one of a first state when reading is incomplete and a second state when reading is complete, each wireless tag returning the identification information upon receiving a corresponding one of the read commands in the sequence that designates the flag state only where the flag state corresponds to the designated flag state;

receiving the identification information from a first wireless tag of the wireless tags by the wireless communication device to acquire the identification information returned from the first wireless tag whose flag state is the first state;

determining, on a basis of the acquired identification information, whether or not a position of the first wireless tag has been detected;

where it is determined that the position of the first wireless tag has not been detected, transmitting, by the wireless communication device, an instruction that instructs the first wireless tag to maintain the flag state to be the first state; and

where it is determined that the position of the first wireless tag has been detected, transmitting, by the wireless communication device, a second read command designating the first state as the flag state without transmitting the instruction, the second read command causing the first wireless tag to rewrite the flag state to the second state by the wireless communication device.