Estimation method and estimation device

An estimation method executed by an estimation device that includes:

• a first radio including a first antenna including M first antenna elements, where M is a natural number greater than or equal to two;
• and a second radio including a second antenna including N second antenna elements, where N is a natural number greater than or equal to two, the estimation method comprising:
• transmitting, using each of the M first antenna elements, a first transmission signal multiple times to a measurement target region;
• observing a plurality of third reception signals that are received by one second antenna element among the N second antenna elements and that include reflection signals reflected from a living body as a result of multiple transmissions of the first transmission signal, for a first period corresponding to a cycle of motion of the living body;
• transmitting, using each of the N second antenna elements, a second transmission signal multiple times to a measurement target region;
• observing a plurality of fourth reception signals that are received by one first antenna element among the M first antenna elements and that include reflection signals reflected from the living body as a result of multiple transmissions of the second transmission signal, for the first period;
• calculating a first combined complex transfer function representing propagation characteristics between the M first antenna elements and the N second antenna elements, based on the plurality of third reception signals and the plurality of fourth reception signals observed for the first period, the first combined complex transfer function comprising a plurality of first combined complex transfer functions;
• calculating a second combined complex transfer function by performing a calculation on the plurality of first combined complex transfer functions according to a predetermined method to reduce effects caused by a clock frequency error and a transmission power error between the first radio and the second radio, the second combined complex transfer function comprising a plurality of second combined complex transfer functions;
• calculating biological information corresponding to a predetermined frequency range of the plurality of second combined complex transfer functions, the predetermined frequency range corresponding to a component related to the living body;
• and
• estimating one of a direction and a location of the living body using the biological information according to a predetermined direction-of-arrival estimation method.

An estimation device comprising:

• a first radio including a first antenna including M first antenna elements, where Mis a natural number greater than or equal to two;
• and
• a second radio including a second antenna including N second antenna elements, where N is a natural number greater than or equal to two,
• wherein the first radio causes one first antenna element among the M first antenna elements to transmit a first transmission signal multiple times to a measurement target region;
• the second radio observes a plurality of first reception signals that are received by the N second antenna elements and that include reflection signals reflected from a living body as a result of multiple transmissions of the first transmission signal, for a first period corresponding to a cycle of motion of the living body;
• the second radio causes one second antenna element among the N second antenna elements to transmit a second transmission signal multiple times to a measurement target region;
• the first radio observes a plurality of second reception signals that are received by the M first antenna elements and that include reflection signals reflected from the living body as a result of multiple transmissions of the second transmission signal, for the first period;
• and
• the estimation device further comprising:
• a first combined complex transfer function calculator that calculates a first combined complex transfer function representing propagation characteristics between the M first antenna elements and the N second antenna elements, based on the plurality of first reception signals and the plurality of second reception signals observed for the first period, the first combined complex transfer function comprising a plurality of first combined complex transfer functions;
• a second combined complex transfer function calculator that calculates a second combined complex transfer function by performing a calculation on the plurality of first combined complex transfer functions according to a predetermined method to reduce effects caused by a clock frequency error and a transmission power error between the first radio and the second radio, the second combined complex transfer function comprising a plurality of second combined complex transfer functions;
• a biological information calculator that extracts biological information corresponding to a predetermined frequency range of the plurality of second combined complex transfer functions, the predetermined frequency range corresponding to a component related to the living body;
• and
• a location estimation processor that estimates one of a direction and a location of the living body using the biological information according to a predetermined direction-of-arrival estimation method.

An estimation device comprising:

• a first radio including a first antenna including M first antenna elements, where M is a natural number greater than or equal to two;
• and
• a second radio including a second antenna including N second antenna elements, where N is a natural number greater than or equal to two,
• wherein the first radio causes each of the M first antenna elements to transmit a first transmission signal multiple times to a measurement target region,
• the second radio observes a plurality of third reception signals that are received by one second antenna element among the N second antenna elements and that include reflection signals reflected from a living body as a result of multiple transmissions of the first transmission signal, for a first period corresponding to a cycle of motion of the living body,
• the second radio causes each of the N second antenna elements to transmit a second transmission signal multiple times to a measurement target region,
• the first radio observes a plurality of fourth reception signals that are received by one first antenna element among the M first antenna elements and that include reflection signals reflected from the living body as a result of multiple transmissions of the second transmission signal, for the first period, and
• the estimation device further comprising:
• a first combined complex transfer function calculator that calculates a first combined complex transfer function representing propagation characteristics between the M first antenna elements and the N second antenna elements, based on the plurality of third reception signals and the plurality of fourth reception signals observed for the first period, the first combined complex transfer function comprising a plurality of first combined complex transfer functions;
• a second combined complex transfer function calculator that calculates a second combined complex transfer function by performing a calculation on the plurality of first combined complex transfer functions according to a predetermined method to reduce effects caused by a clock frequency error and a transmission power error between the first radio and the second radio, the second combined complex transfer function comprising a plurality of second combined complex transfer functions;
• a biological information calculator that extracts biological information corresponding to a predetermined frequency range of the plurality of second combined complex transfer functions, the predetermined frequency range corresponding to a component related to the living body;
• and
• a location estimation processor that estimates one of a direction and a location of the living body using the biological information according to a predetermined direction-of-arrival estimation method.