US-12628117-B2 - Position determination timing selection device, wireless communication system, position determination timing selection method, and recording medium

US12628117B2US 12628117 B2US12628117 B2US 12628117B2US-12628117-B2

Abstract

Channel identification information indicating a channel measured by each of a plurality of measurement devices that measure a radio wave strength of radio waves propagating in the channel used by a wireless terminal device for radio wave transmission, and information indicating a measurement time at which the measurement was performed are acquired. For each channel, a time at which number of the measurement devices performing measurement satisfies a predetermined condition defined in advance is selected based on the acquired channel identification information of each measurement device and the information indicating the measurement time. A position determination time for each channel from each selected time is selected, and the channel identification information indicating the channel used by the wireless terminal device subject to position determination is acquired.

Inventors

Takeo Hidaka

Assignees

NEC CORPORATION

Dates

Publication Date: 20260512
Application Date: 20220125
Priority Date: 20210316

Claims (11)

1 . A position determination timing selection device comprising: a memory configured to store instructions; and a processor configured to execute the instructions to: acquire channel identification information indicating a channel measured by each of a plurality of measurement devices that measure a radio wave strength of radio waves propagating in the channel used by a wireless terminal device for radio wave transmission, and information indicating a measurement time at which the measurement was performed; for each channel, select a time at which number of the measurement devices performing measurement satisfies a predetermined condition defined in advance based on the acquired channel identification information of each measurement device and the information indicating the measurement time, and select a position determination time for each channel from each selected time; acquire the channel identification information indicating the channel used by the wireless terminal device subject to position determination; and transmit a response request signal addressed to the wireless terminal device subject to the position determination at the selected position determination time for the channel of the acquired channel identification information.
2 . The position determination timing selection device according to claim 1 , wherein the processor is configured to execute the instructions to arbitrarily determine a measurement period of a certain length of time including a plurality of consecutive time intervals each of which has a certain length of time, set the predetermined condition as maximum number of the measurement devices that perform measurement in each of measurement periods including the measurement period, select in each of the measurement periods a time of the time interval in which number of the measurement devices that perform measurement reaches maximum number for each channel based on the acquired channel identification information of each measurement device and the measurement time, and select each of the selected times as the position determination time of each of the measurement periods for each of the channels.
3 . The position determination timing selection device according to claim 2 , wherein the processor is configured to execute the instructions to, when there exists the measurement device whose measurement time exists in the measurement period but is not included in the position determination time, further select, as the position determination time, the time indicated by the time interval within the same measurement period during which the measurement device not included in the position determination time performs measurement.
4 . The position determination timing selection device according to claim 2 , wherein the processor is configured to execute the instructions to, when selecting the position determination time, when there are a plurality of the time intervals that are candidates for the position determination time, select the time indicated by the earliest time interval as the position determination time.
5 . The position determination timing selection device according to claim 1 , wherein the processor is configured to execute the instructions to arbitrarily define a measurement period of a certain length of time, set the predetermined condition as maximum number of the measurement devices that perform measurement in each of the measurement periods, select in each of the measurement periods a time in which number of the measurement devices that perform measurement reaches maximum number for each channel, based on the acquired channel identification information of each measurement device and the measurement time, arbitrarily select a portion of a predetermined time length in each selected time, and select each selected portion as the position determination time of each measurement period for each channel.
6 . The position determination timing selection device according to claim 1 , wherein the processor is configured to execute the instructions to arbitrarily define a time interval of a certain length of time, set the predetermined condition as number of the radio wave strengths required for position determination of the wireless terminal device determined in accordance with position determination accuracy or number of the radio wave strengths that is greater than the number of the radio wave strengths required for the position determination of the wireless terminal device, select for each channel a time of the time interval in which the number of the measurement devices that perform measurement is equal to or greater than the number of radio wave strengths required for the position determination of the wireless terminal device determined in accordance with the position determination accuracy based on the acquired channel identification information of each measurement device and the measurement time, and select each of the selected times as the position determination time of each measurement period for each channel.
7 . The position determination timing selection device according to claim 6 , wherein the processor is configured to execute the instructions to, when the selected position determination times are consecutive, and when a combination of the measurement devices in the consecutive position determination times is the same, set only the earliest position determination time as the position determination time.
8 . The position determination timing selection device according to claim 1 , wherein the processor is configured to execute the instructions to set the predetermined condition as number of the radio wave strengths required for position determination of the wireless terminal device determined in accordance with a position determination accuracy or number of the radio wave strengths that is greater than the number of the radio wave strengths required for the position determination of the wireless terminal device, select for each channel a time in which number of the measurement devices that perform measurement is equal to or greater than the number of radio wave strengths required for the position determination of the wireless terminal device determined in accordance with the position determination accuracy based on the acquired channel identification information of each measurement device and the measurement time, arbitrarily select a portion of a predetermined time length in each of the selected times, and select each of the selected times as the position determination time of each measurement period for each channel.
9 . The position determination timing selection device according to claim 1 , wherein the processor is configured to execute the instructions to exclude the wireless terminal device that is the destination of the response request signal from a position determination target if no response signal corresponding to the transmitted response request signal is received.
10 . A wireless communication system comprising: a wireless terminal device; a plurality of measurement devices that measure a radio wave strength of radio waves propagating in a channel used by the wireless terminal device for radio wave transmission; and a position determination timing selection device, wherein the position determination timing selection device comprises: a memory configured to store instructions; and a processor configured to execute the instructions to: acquire channel identification information indicating the channel measured by each of the plurality of measurement devices, and information indicating a measurement time at which the measurement was performed; for each channel, select a time at which number of the measurement devices performing measurement satisfies a predetermined condition defined in advance based on the acquired channel identification information of each measurement device and the information indicating the measurement time, and select a position determination time for each channel from each selected time; acquire the channel identification information indicating the channel used by the wireless terminal device subject to position determination; and transmit a response request signal addressed to the wireless terminal device subject to the position determination at the selected position determination time for the channel of the acquired channel identification information.
11 . A position determination timing selection method comprising: acquiring channel identification information indicating a channel measured by each of a plurality of measurement devices that measure a radio wave strength of radio waves propagating in the channel used by a wireless terminal device for radio wave transmission, and information indicating a measurement time at which the measurement was performed; selecting, for each channel, a time at which number of the measurement devices performing measurement satisfies a predetermined condition defined in advance based on the acquired channel identification information of each measurement device and the information indicating the measurement time; selecting a position determination time for each channel from each selected time; acquiring the channel identification information indicating the channel used by the wireless terminal device subject to position determination; and transmitting a response request signal addressed to the wireless terminal device subject to the position determination at the selected position determination time for the channel of the acquired channel identification information.

Description

This application is a National Stage Entry of PCT/JP2022/002590 filed on Jan. 25, 2022, which claims priority from Japanese Patent Application 2021-042605 filed on Mar. 16, 2021, the contents of all of which are incorporated herein by reference, in their entirety. TECHNICAL FIELD The present invention relates to a position determination timing selection device, a wireless communication system, a position determination timing selection method, and a recording medium. BACKGROUND ART There is a service that locates the position of a wireless terminal device, such as a smartphone owned by the user, based on the radio wave strength of the wireless terminal device. To measure radio wave strength, a wireless terminal device must emit radio waves into the air. The following two methods exist for radiating radio waves. One method is triggered by the wireless terminal device side. In this method, for example, an application program for positioning is installed in a wireless terminal device, and when the application program runs, the wireless terminal device radiates radio waves for positioning. The other method is triggered by the network side. In this method, an external terminal device that connects to the wireless terminal device via the communication network sends a response request packet to the wireless terminal device at the timing for positioning. When the wireless terminal device receives the response request packet, it sends a response packet and radiates radio waves when sending the response packet. This radio wave is the radio wave for positioning. A common issue with these methods is that if the wireless terminal device emits excessive radio waves for positioning, the battery of the wireless terminal device is drained significantly, while if the intervals between radio wave emissions are thinned out, the frequency and accuracy of positioning updates will be reduced. In view of these issues, there are technologies to reduce battery drain of wireless terminal devices, as disclosed in, for example, Patent Documents 1 and 2. PRIOR ART DOCUMENTS Patent Documents Patent Document 1: Japanese Unexamined Patent Application, First Publication No. 2006-245930Patent Document 2: Japanese Unexamined Patent Application, First Publication No. 2007-053483 SUMMARY OF THE INVENTION Problems to be Solved by the Invention The invention described in Patent Document 1 was made for the purpose of enabling location search operation for a longer period of time with a simple operation by making it low power and improving user convenience in a communication terminal with an added location search function. In the invention described in Patent Document 1, after the power supply is turned off, the location information acquired by the location information acquisition means is transmitted to another terminal or monitoring device via a network by a communication means, thereby reducing power consumption. However, the invention described in Patent Document 1 aims to achieve low power consumption by performing positioning triggered by the power-off operation by the power key. Therefore, it is necessary to add a new function to the wireless terminal device, for example, installing an application program to perform positioning triggered by the power-off operation using the power key. The invention described in Patent Document 2 is an invention made for the purpose of providing a method for obtaining location information for a wireless terminal device set to power-saving mode. The invention described in Patent Document 2 does not use the wireless terminal device side as the trigger for positioning as in Patent Document 1, but instead uses the network side as the trigger for positioning. In the invention described in Patent Document 2, an access point (hereinbelow referred to as an AP) transmits a beacon frame containing stored data information to the effect that there is stored data, regardless of whether there is stored data addressed to the wireless terminal device that has entered the power-saving mode. The wireless terminal device that has transitioned to the power-saving mode and entered the Dawes state transitions to the awake state before receiving the beacon frame and refers to the received beacon frame. The beacon frame referred to by the wireless terminal device contains stored data information that indicates the presence of stored data regardless of the presence or absence of the stored data. Therefore, the wireless terminal device judges that there is stored data and sends a stored data request frame to the AP. At that time, since the wireless terminal device radiates radio waves, positioning can be performed based on those radio waves. If the stored data does not actually exist, the AP sends dummy data to the wireless terminal device, and the wireless terminal device that receives the dummy data transitions back to power-saving mode. This enables positioning of the wireless terminal device while achieving power efficiency in the