JP6657148B2 - Wireless communication system and terminal information collection method - Google Patents

Description

  According to the present invention, there are provided a plurality of communication cells to which a wireless base station and one or more wireless terminal stations are connected, a central control station connected to a wireless base station of each communication cell, and a wireless terminal of each communication cell. The present invention relates to a wireless communication system and a terminal information collection method in which a central control station collects terminal information used for grasping the status of a station. Here, an example of the terminal information includes propagation channel information between a wireless base station and a wireless terminal station.

  As a service to which RSSI (Received Signal Strength Indicator) which is signal strength information of a wireless signal is applied, there is a position providing service of a wireless terminal station in a wireless LAN system. As an example of a method for realizing this service, there is a method in which a wireless terminal station measures RSSI from beacon signals transmitted from a plurality of wireless base stations and calculates the position of the wireless terminal station from the plurality of RSSIs (for example, Patent Document 1). As another application example, a service for detecting human activity from the fluctuation characteristics of RSSI has been studied (for example, Non-Patent Document 2).

  Further, in order to further improve the performance of the above service, studies using propagation channel information (CSI: Channel State Information) in addition to RSSI have been advanced. The propagation channel information in the wireless LAN system is a propagation path response (amplitude information and a phase difference between antennas) for each subcarrier in a path between the wireless base station antenna and the wireless terminal station antenna. For example, Non-Patent Document 3 discusses a technique for improving accuracy in position estimation, activity detection, and the like by using propagation channel information.

Navarro Eduardo, 2011. “Wi-Fi Localization Using RSSI Fingerprinting”, California Polytechnic State University, United States of America.http: //digitalcommons.calpoly.edu/cpesp/17/ (17 Aug. 2011) Wang, Wei, et al. "Understanding and modeling of wifi signal based human activity recognition." Proceedings of the 21st annual international conference on mobile computing and networking.ACM, 2015. Yang, Zheng, Zimu Zhou, and Yunhao Liu. "From RSSI to CSI: Indoor localization via channel response." ACM Computing Surveys (CSUR) 46.2 (2013): 25.

  In order to apply the study technology described in the latter half of the background technology to an actual system and provide stable services, it is necessary to collect RSSI and propagation channel information at high frequency. When collecting RSSI, since it is possible to use a constantly transmitted signal such as a beacon signal, and since RSSI is a small amount of power information common to all subcarriers, it is assumed that RSSI is frequently collected. However, the load on the wireless LAN system is small. On the other hand, when collecting the propagation channel information, an additional signal for collecting the propagation channel information, for example, a measurement signal for measuring the propagation channel information transmitted by the radio base station or the radio terminal station transmits the propagation channel information. Since a notification signal or the like which measures and responds is required, and the amount of information of a single unit becomes extremely large, collection at a high frequency puts a load on the wireless LAN system.

FIG. 12 shows a configuration example of a conventional wireless communication system.
In FIG. 12, a radio base station 10-i and one or more radio terminal stations 20-ij each constitute a communication cell 50-i. Here, i represents an example of 1-3 and j represents an example of 1-3. The radio base station 10-i collects propagation channel information with the subordinate radio terminal stations 20-ij, and transfers the collected information to the central control station 40.

FIG. 13 shows a conventional terminal information collecting operation example.
In FIG. 13, each wireless base station 10-i transmits a measurement signal M for measuring propagation channel information to its subordinate wireless terminal stations 20-ij. Next, the radio terminal station 20-ij measures the propagation channel information from the received measurement signal M, and notifies the radio base station 10-i to which the measurement result belongs by the notification signal R. When the collection of the propagation channel information is completed, each radio base station 10-i transmits a transfer signal storing the propagation channel information to the centralized control station 40 with a time lag, and the centralized control station 40 To get.

  In such a conventional method of collecting propagation channel information, each radio base station 10-i individually collects the propagation channel information of the subordinate radio terminal stations 20-ij, and the propagation channel information collected by each radio base station 10-i. Since the channel information is transferred to the central control station 40 with a time lag, a large transfer time is required.

  SUMMARY OF THE INVENTION The present invention provides a method for efficiently transmitting terminal information, such as propagation channel information between a wireless base station and a wireless terminal station, in a wireless communication system in which a plurality of communication cells connect a wireless base station and one or more wireless terminal stations. It is an object of the present invention to provide a wireless communication system and a terminal information collection method that can collect information well.

  In the first invention, there are a plurality of communication cells to which a wireless base station and one or more wireless terminal stations are connected, and a central control station collects terminal information used for grasping the status of each wireless terminal station in each communication cell. In a wireless communication system, the wireless base station includes one or more collection stations that are arranged at positions where wireless signals transmitted by wireless terminals of respective communication cells can be received and are connected to a central control station via a wireless line. The station includes means for transmitting a measurement signal for measuring terminal information of a subordinate wireless terminal station, and each wireless terminal station measures terminal information by the measurement signal and transmits the terminal information to a wireless base station to which the wireless terminal station belongs as a notification signal The collecting station receives and collects the notification signal, and includes means for transmitting a transfer signal formed by combining each terminal information of each wireless terminal station to the central control station, and the central control station includes: Resolves the transmitted signal transmitted from the collection station. And includes means for collecting the terminal information of each wireless terminal station.

  In the wireless communication system according to the first aspect of the invention, the collection station includes means for combining the terminal information of each wireless terminal station and performing a predetermined compression process to form a transfer signal. It includes means for analyzing and further performing decompression processing corresponding to compression processing to restore terminal information. Here, the predetermined compression processing may generate difference information of terminal information in a frequency, space, or time direction. In the predetermined compression processing, information having a high correlation in the terminal information in the frequency or space direction may be integrated, or information having a high correlation in the terminal information in the time direction may be deleted.

  According to a second invention, there are a plurality of communication cells to which a wireless base station and one or more wireless terminal stations are connected, and a central control station collects terminal information used for grasping the status of each wireless terminal station in each communication cell. In the terminal information collecting method of the wireless communication system, the wireless communication system is arranged at a position where a wireless signal transmitted by each wireless terminal station of each communication cell can be received, and is connected to a central control station via a wireless line. Comprising at least one collection station, the wireless base station has a step of transmitting a measurement signal for measuring terminal information of a subordinate wireless terminal station, and each wireless terminal station measures terminal information based on the measurement signal. Transmitting a notification signal as a notification signal to a wireless base station belonging to the collection station. The collection station receives and collects the notification signal, and centrally controls a transfer signal formed by combining each terminal information of each wireless terminal station. Has the step of transmitting to the station , Central control station analyzes the transfer signal transmitted from a collection station, comprising the step of collecting the terminal information of each wireless terminal station.

  In the terminal information collection method of the second invention, the collection station has a step of combining the terminal information of each wireless terminal station, and further performing a predetermined compression process to form a transfer signal. Analyzing the signal and performing a decompression process corresponding to the compression process to restore the terminal information; Here, the predetermined compression processing may generate difference information of terminal information in a frequency, space, or time direction. In the predetermined compression processing, information having a high correlation in the terminal information in the frequency or space direction may be integrated, or information having a high correlation in the terminal information in the time direction may be deleted.

  According to the present invention, the collection efficiency can be enhanced by collecting terminal information of each wireless terminal station at the collection station and collectively transferring the terminal information to the central control station.

FIG. 1 is a diagram illustrating a configuration example of a wireless communication system according to the present invention. 5 is a time chart illustrating an example of a terminal information collection operation according to the first embodiment of the present invention. It is a figure which shows the example of connection of propagation channel information. FIG. 2 is a diagram illustrating a configuration example of a wireless base station 10 according to the first embodiment. FIG. 2 is a diagram illustrating a configuration example of a wireless terminal station 20 according to the first embodiment. FIG. 3 is a diagram illustrating a configuration example of a collection station 30 according to the first embodiment. FIG. 3 is a diagram illustrating a configuration example of a central control station 40 according to the first embodiment. FIG. 9 is a diagram illustrating a configuration example of a collection station 30 according to a second embodiment. FIG. 13 is a diagram illustrating a configuration example of a central control station 40 according to the second embodiment. FIG. 14 is a diagram illustrating a configuration example of a collection station 30 according to a third embodiment. FIG. 14 is a diagram illustrating a configuration example of a wireless base station 10 according to a third embodiment. FIG. 11 is a diagram illustrating a configuration example of a conventional wireless communication system. 9 is a time chart showing a conventional terminal information collecting operation example.

FIG. 1 shows a configuration example of a wireless communication system of the present invention.
In FIG. 1, the wireless communication system has a configuration in which there are a plurality of communication cells 50-i to which a wireless base station 10-i and one or more wireless terminal stations 20-ij are connected. Here, an example in which i is 1 to 3 and j is 1 to 3 is shown. Further, at least one collection station 30 is arranged at a position where a radio signal transmitted by the radio terminal station 20-ij of each communication cell 50-i can be received, and the collection station 30 and the central control station 40 communicate via a radio line. Connected. The radio base station 10-i and the central control station 40 are also connected via a radio line, but are omitted here.

(Example 1)
FIG. 2 illustrates an example of a terminal information collection operation according to the first embodiment of the present invention. Here, as an example of terminal information collected by the central control station 40, propagation channel information will be described.
In FIG. 2, a radio base station 10-1 transmits a measurement signal M for measuring propagation channel information to subordinate radio terminal stations 20-11 and 20-12, and the radio terminal stations 20-11 and 20-12. Reference numeral -12 measures the propagation channel information between the radio base station 10-1 and the own station from the measurement signal of the radio base station 10-1.

  Next, the radio terminal stations 20-11 and 20-12 report the measured propagation channel information to the radio base station 10-1 using the notification signal R in a predetermined order. At the same time, the collection station 30 receives the notification signals R transmitted from the wireless terminal stations 20-11 and 20-12 to the wireless base station 10-1 in a predetermined order, and transmits the propagation channel information in each wireless terminal station. collect.

  Next, measurement is similarly performed between the radio base station 10-2 and the subordinate radio terminal station 20-21, and between the radio base station 10-3 and the subordinate radio terminal stations 20-31 to 20-33. The transmission of the signal M, the measurement of the propagation channel information, and the transmission of the notification signal R are performed. At the same time, the collection station 30 also receives the respective notification signals R and collects the propagation channel information in each wireless terminal station. The timing and cycle at which the wireless base stations 10-1 to 10-3 each transmit the measurement signal M are set in advance or by using a control signal transmitted from the collection station 30 according to the third embodiment described later. It may be controlled.

  Next, the collection station 30 transmits the collected propagation channel information CSI between the radio base stations 10-1 to 10-3 and the radio terminal stations 20-11 to 20-33 to the subcarriers # 1, # 2, # .., And are combined as data in a predetermined format as shown in FIG. Here, CSI (a, b, #c) indicates the propagation channel information of the subcarrier #c between the radio base station 10-a and the radio terminal station 20-b.

  Further, the collection station 30 forms a transfer signal from the combined propagation channel information and transfers it to the central control station 40. Finally, the central control station 40 receives the transfer signal transferred from the collection station 30, and stores the propagation channel information of each wireless terminal station 20-ij extracted from the transfer signal in a time series.

  In this way, the collection station 30 collects the propagation channel information of each wireless terminal station 20-ij, and further collectively transfers the propagation channel information to the central control station 40, so that the propagation channel information can be collected with high efficiency.

  FIG. 4 illustrates a configuration example of the wireless base station 10 according to the first embodiment. Here, only the main functional blocks related to the present invention are extracted and shown, and the functional blocks used in a general radio base station and the description thereof are omitted.

  In FIG. 4, the radio base station 10 includes an antenna 11, a transmission unit 12, and a measurement signal generation unit 13. In addition, a configuration corresponding to MIMO transmission using a plurality of antennas 11 may be employed. The measurement signal generation unit 13 generates a measurement signal for the wireless terminal station 20 to measure the propagation channel information, and outputs the measurement signal to the transmission unit 12. The transmission unit 12 converts the measurement signal generated by the measurement signal generation unit 13 into a wireless LAN signal addressed to a subordinate wireless terminal station, and transmits the signal from the antenna 11 as a wireless signal.

  FIG. 5 illustrates a configuration example of the wireless terminal station 20 according to the first embodiment. Here, only the main functional blocks related to the present invention are extracted and shown, and the functional blocks generally used in the wireless terminal station and the description thereof are omitted.

  In FIG. 5, the radio terminal station 20 includes an antenna 21, a transmission unit 22, a reception unit 23, a notification signal generation unit 24, and a propagation channel information measurement unit 25. Note that a configuration corresponding to MIMO transmission using a plurality of antennas 21 may be employed. The receiving unit 23 converts the radio signal received by the antenna 21 into a measurement signal that can be handled by the propagation channel information measurement unit 25 and outputs the measurement signal to the propagation channel information measurement unit 25. The propagation channel information measurement unit 25 measures the propagation channel information from the measurement signal input from the reception unit 23, and outputs the measurement result to the notification signal generation unit 24. The notification signal generation unit 24 generates a notification signal including the propagation channel information input from the propagation channel information measurement unit 25, and outputs the notification signal to the transmission unit 22. The transmission unit 22 converts the notification signal input from the notification signal generation unit 24 into a wireless LAN signal addressed to the wireless base station 10 and the collection station 30, and transmits the wireless LAN signal from the antenna 21.

FIG. 6 illustrates a configuration example of the collection station 30 according to the first embodiment.
6, the collection station 30 includes an antenna 31, a transmission unit 32, a reception unit 33, a collection unit 34, a combining unit 35, and a transfer signal generation unit 36. Note that a configuration corresponding to MIMO transmission using a plurality of antennas 31 may be employed.

  The receiving unit 33 converts the radio signal received by the antenna 31 into a notification signal that can be handled by the collecting unit 34, and outputs the notification signal to the collecting unit 34. The collection unit 34 collects the propagation channel information from the notification signal of each wireless terminal station input from the reception unit 33 and outputs the collection result to the combining unit 35. The combining unit 35 combines the propagation channel information input from the collecting unit 34 as shown in FIG. The transfer signal generation unit 36 generates a transfer signal for collectively transferring the propagation channel information input from the combining unit 35, and outputs the transfer signal to the transmission unit 32. The transmission unit 32 converts the transfer signal input from the transfer signal generation unit 36 into a wireless LAN signal addressed to the central control station 40 and transmits the wireless signal from the antenna 31 as a wireless signal.

  FIG. 7 illustrates a configuration example of the central control station 40 according to the first embodiment. Here, only the main functional blocks related to the present invention are extracted and shown, and the functional blocks generally used in the central control station and the description thereof are omitted.

  7, the central control station 40 includes an antenna 41, a receiving unit 42, a transfer signal analyzing unit 43, and a storage unit 44. Note that a configuration corresponding to MIMO transmission using a plurality of antennas 41 may be employed. The receiving unit 42 converts the wireless signal received by the antenna 41 into a transfer signal that can be handled by the transfer signal analysis unit 43 and outputs the transfer signal to the transfer signal analysis unit 43. The transfer signal analyzer 43 extracts the coupled propagation channel information from the transfer signal of the collection station input from the receiver 42 and outputs the extraction result to the storage 44. The storage unit 44 stores the propagation channel information of each wireless terminal station input from the transfer signal analysis unit 43 in chronological order.

  Although the case where the number of the collection stations 30 is one has been described here, a plurality of the collection stations 30 are distributed to positions where the notification signal (propagation channel information) transmitted by the wireless terminal station 20-ij of each communication cell 50-i can be received. May be provided. In this case, the propagation channel information collected by each collection station 30 is combined and transferred to the central control station 40 with a time lag. Alternatively, one collection station 30 of the plurality of collection stations may re-collect the propagation channel information collected by the other collection stations 30 and collectively transfer the propagation channel information to the central control station 40. In addition, as for the propagation channel information that cannot be collected by the collection station 30 because there is a radio terminal station 20-ij remote from the collection station 30, the radio base station 10-i to which the radio terminal station 20-ij belongs is assigned in the same manner as in the related art. Alternatively, the information may be transferred to the central control station 40.

(Example 2)
The feature of the second embodiment is that in the wireless communication system shown in FIG. 1, the efficiency is improved by compressing a transfer signal from the collection station 30 to the central control station 40.

FIG. 8 illustrates a configuration example of the collection station 30 according to the second embodiment.
8, the collection station 30 includes an antenna 31, a transmission unit 32, a reception unit 33, a collection unit 34, a combining unit 35, a transfer signal generation unit 36, and a compression unit 37. Here, the same components as those of the collection station 30 of the first embodiment are denoted by the same reference numerals, and description thereof will be omitted.

  The compression unit 37 compresses the propagation channel information input from the combining unit 35 and outputs the information to the transfer signal generation unit 36. The transfer signal generation unit 36 generates a transfer signal for collectively transferring the information compressed by the compression unit 37, and outputs the transfer signal to the transmission unit 32.

The following methods are selected or combined as the compression method.
(1) File compression: The propagation channel information is converted into bit information, and the transfer amount of the propagation channel information is reduced by a general file compression method such as a ZIP format.
(2) Frequency compression: The transfer channel information is reduced by referring to the propagation channel information shown in FIG. 3 in the subcarrier direction (horizontal direction) and integrating information having a high correlation or as difference information. .
(3) Spatial compression: Refers to the propagation channel information shown in FIG. 3 in the direction of the wireless terminal station (vertical direction), and integrates information having a high correlation or reduces the amount of transfer of propagation channel information by using difference information. I do.

(4) Time compression: The transfer amount of the propagation channel information is reduced by referring to the previously collected propagation channel information and the latest propagation channel information and transferring the respective difference information, or by reducing the information having a high correlation.
(5) Compression by limiting the number of bits: When converting propagation channel information into bit information, the number of bits to be converted is adjusted to reduce the transfer amount of propagation channel information.

FIG. 9 illustrates a configuration example of a central control station 40 according to the second embodiment.
9, the central control station 40 includes an antenna 41, a receiving unit 42, a transfer signal analyzing unit 43, a storage unit 44, and a decompressing unit 45. Here, the same components as those of the central control station 40 of the first embodiment are denoted by the same reference numerals, and description thereof is omitted.

  The transfer signal analyzer 43 extracts the compressed propagation channel information from the transfer signal of the collection station 30 input from the receiver 42 and outputs the extraction result to the decompressor 45. The decompression unit 45 decompresses the information input from the transfer signal analysis unit 43 according to the compression method in the collection station 30 and outputs the restored propagation channel information to the storage unit 44. The storage unit 44 stores the restored propagation channel information input from the transfer signal analysis unit 43 in chronological order.

(Example 3)
The feature of the third embodiment is that the measurement station of the propagation channel information is controlled from the collection station 30 to the radio base station 10-i, for example, according to the necessity of measuring the propagation channel information for each radio base station 10-i. By controlling the measurement signal to be transmitted at the measured measurement intervals, unnecessary transmission and reception of the measurement signal and the notification signal are avoided to achieve higher efficiency.

FIG. 10 illustrates a configuration example of the collection station 30 according to the third embodiment.
In FIG. 10, the collection station 30 includes an antenna 31, a transmission unit 32, a reception unit 33, a collection unit 34, a combining unit 35, a transfer signal generation unit 36, a compression unit 37, and a control signal generation unit 38. Here, the same components as those of the collection stations of the first and second embodiments are denoted by the same reference numerals, and description thereof will be omitted.

  The control signal generator 38 generates a control signal for controlling a transmission cycle of a measurement signal for measuring propagation channel information of each radio base station 10-i, and outputs the control signal to the transmitter 32. The transmission unit 32 converts the control signal input from the control signal generation unit 38 into a wireless LAN signal, and transmits the signal from the antenna 31.

FIG. 11 illustrates a configuration example of the wireless base station 10 according to the third embodiment.
In FIG. 11, the radio base station 10 includes an antenna 11, a transmission unit 12, a measurement signal generation unit 13, a reception unit 14, and a control signal analysis unit 15. Here, the same components as those of the wireless base station according to the first embodiment are denoted by the same reference numerals, and description thereof is omitted.

  The receiver 14 converts the signal received by the antenna 11 into a control signal that can be handled by the control signal analyzer 15 and outputs the control signal to the control signal analyzer 15. The control signal analyzer 15 extracts the measurement cycle of the propagation channel information from the control signal transmitted from the collection station 30, and sets the measurement cycle in the measurement signal generator 13. The measurement signal generation unit 13 generates a measurement signal for the wireless terminal station 20 to measure the propagation channel information based on the measurement cycle set by the control signal analysis unit 15, and outputs the measurement signal to the transmission unit 12.

REFERENCE SIGNS LIST 10 radio base station 11 antenna 12 transmission unit 13 measurement signal generation unit 14 reception unit 15 control signal analysis unit 20 wireless terminal station 21 antenna 22 transmission unit 23 reception unit 24 notification signal generation unit 25 propagation channel information measurement unit 30 collection station 31 antenna Reference Signs List 32 transmitting unit 33 receiving unit 34 collecting unit 35 combining unit 36 transfer signal generating unit 37 compressing unit 38 control signal generating unit 40 central control station 41 antenna 42 receiving unit 43 transfer signal analyzing unit 44 storage unit 45 decompressing unit 50 communication cell

Claims (8)

In a wireless communication system in which there are a plurality of communication cells to which a wireless base station and one or more wireless terminal stations are connected, and a centralized control station collects terminal information used for grasping the status of each wireless terminal station in each communication cell,
It is arranged at a position where it can receive a radio signal transmitted by each radio terminal station of each communication cell, and comprises one or more collection stations connected via a radio line with the central control station,
The wireless base station includes a unit that transmits a measurement signal for measuring the terminal information of a subordinate wireless terminal station,
Each of the wireless terminal stations includes a means for measuring the terminal information by the measurement signal, and transmitting the terminal information to the associated wireless base station as a notification signal,
The collection station receives and collects the notification signal, and includes means for transmitting a transfer signal formed by combining each terminal information of each wireless terminal station to the central control station,
The centralized control station includes means for analyzing the transfer signal transmitted from the collection station and collecting terminal information of each of the wireless terminal stations. The wireless communication system according to claim 1,
The collection station includes means for combining the terminal information of each of the wireless terminal stations, and further performing a predetermined compression process to form the transfer signal,
The radio communication system according to claim 1, wherein the central control station analyzes the transfer signal, and further performs a decompression process corresponding to the compression process to restore the terminal information. The wireless communication system according to claim 2,
The wireless communication system, wherein the predetermined compression process generates difference information of the terminal information in a frequency, space, or time direction. The wireless communication system according to claim 2,
The predetermined compression process integrates information having a high correlation in the terminal information in a frequency or space direction, or deletes information having a high correlation in the terminal information in a time direction. There are a plurality of communication cells to which a wireless base station and one or more wireless terminal stations are connected, and terminal information of a wireless communication system in which a central control station collects terminal information used for grasping the status of each wireless terminal station in each communication cell In the collection method,
The wireless communication system includes one or more collection stations that are arranged at positions where a wireless signal transmitted by each wireless terminal station of each communication cell can be received, and are connected to the central control station via a wireless line. ,
The wireless base station has a step of transmitting a measurement signal for measuring the terminal information of the subordinate wireless terminal station,
The wireless terminal station has a step of measuring the terminal information by the measurement signal, and transmitting the terminal information as a notification signal to the associated wireless base station,
The collection station has a step of receiving and collecting the notification signal, transmitting a transfer signal formed by combining the terminal information of the wireless terminal stations to the central control station,
The centralized control station has a step of analyzing the transfer signal transmitted from the collection station and collecting terminal information of each wireless terminal station. The terminal information collecting method according to claim 5,
The collection station has a step of combining the terminal information of each of the wireless terminal stations, further performing a predetermined compression process to form the transfer signal,
The terminal information collecting method, comprising: analyzing the transfer signal, and further performing a decompression process corresponding to the compression process to restore the terminal information. The terminal information collection method according to claim 6,
The terminal information collection method, wherein the predetermined compression process generates difference information of the terminal information in a frequency, space, or time direction. The terminal information collection method according to claim 6,
The predetermined compression processing integrates information having a high correlation in the terminal information in a frequency or space direction, or deletes information having a high correlation in the terminal information in a time direction. .

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