JP2017041733A - Radio communication system and control method thereof, base station device, and radio communication terminal - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a radio communication system capable of keeping down the battery consumption of a radio communication terminal.SOLUTION: A base station adopting high-frequency RAT (Radio Access Technology) comprises a wireless LAN transmission signal generation unit and a transmission output control unit that are advertisement means for advertising a beacon (guide beacon) including operation information on radio communication at the base station on a prescribed channel (guide channel) by using a wireless LAN communication format. A terminal device comprises a control unit that activates a high-frequency RAT communication function unit and controls it to be able to communicate with the base station adopting the high-frequency RAT by using the operation information when receiving the beacon.SELECTED DRAWING: Figure 9

Description

  The present invention relates to mobile communication technology, and more particularly to connection technology for wireless communication terminals that support a plurality of wireless communication formats.

  Mobile communication has been rapidly spreading in recent years, and a smartphone equipped with cellular wireless communication and wireless LAN (see Non-Patent Document 1) of standards such as 3G (third generation mobile communication system) and LTE (Long Term Evolution), A tablet device is used.

  Mobile communication will further develop in the future, and one of the directions is HetNet (Heterogeneous Network) (see Non-Patent Document 2). This is not a single technique but a system that forms a network by combining different techniques, wireless cells of various sizes, and various bands (see FIG. 1). In the example of FIG. 1, a plurality of cells such as a macro cell 10 having a wide cover area and a small cell 20 having a small cover area but capable of high-speed communication are overlapped to flexibly form a network according to demand. . In addition to the difference in cell coverage, different wireless technologies such as cells 10 and 20 for cellular wireless communication and cell 30 for wireless LAN may be combined. As mobile communication traffic increases in the future, it is conceivable that the frequency will run short, and a network for mobile communication is constructed by combining various wireless technologies at various frequencies than before with HetNet. Therefore, it is assumed that the wireless communication interface of the terminal will also become multiband, multi-RAT (Radio Access Technology). For example, cellular communication and wireless LAN are generally used as wireless communication interfaces for Internet connection currently installed in smartphones. However, in the future, RAT with a higher frequency (for example, a millimeter wave band of about 60 GHz) will be used. A wireless communication interface may be added. Currently, there is WiGig (registered trademark) (IEEE802.11ad) (see Non-Patent Document 3) as a 60 GHz band wireless communication standard.

  In a HetNet environment, in order for terminals to use different RATs and different band cells by connecting / disconnecting them appropriately, it is necessary to efficiently find and connect cells. In the conventional wireless communication system, when there are a plurality of wireless interfaces, the terminal searches for a wireless base station independently (see FIG. 2). For example, in the case of a wireless LAN, 14 channels in the 2.4 GHz band can be used in Japan, and 19 channels in the 5 GHz band can be used. There are various channels operated by the base station. Search all channels to find a cell. As a method of searching for wireless communication, a signal for the target channel is received for a certain period of time, a passive scan for acquiring the broadcast signal of the base station, or a signal for inquiry in the target channel is transmitted, and a response from the base station is received. There is an active scan that receives a signal. For example, in a wireless LAN, although it depends on the period of a beacon signal to be notified, a search for one channel requires about several tens to 100 ms. When searching for the number of channels, it takes several seconds to scan all channels. In order to find a cell while moving, it is necessary to continuously scan and consume the battery of the terminal.

  As an example of a technique for shortening the channel scan, a technique called IEEE 802.11ai FILS (First Initial Link Setup) (see Non-Patent Document 4) has been standardized to increase the speed of wireless LAN connection. This is to accelerate NW discovery with a beacon signal of limited information in a short period (for example, 20 ms) called Discovery Frame in addition to a normal beacon signal (for example, 100 ms interval).

IEEE Standard for Information technology-Telecommunications and information exchange between systems Local and metropolitan area networks-Specific requirements, "Part 11: Wireless LAN Medium Access Control (MAC) and Physical Layer (PHY) Specifications", IEEE, March 2012 J. Wannstrom, K. Mallinson, "Heterogeneous Networks in LTE", [online], [Search June 22, 2015], Internet <URL: http: //www.3gpp.org/technologies/keywords-acronyms/ 1576-hetnet> IEEE Standard for Information technology-Telecommunications and information exchange between systems Local and metropolitan area networks-Specific requirements, "Part 11: Wireless LAN Medium Access Control (MAC) and Physical Layer (PHY) Specifications Amendment 3: Enhancements for Very High Throughput in the 60 GHz Band ", IEEE, December 2012 IEEE P802.11ai / D3.0, Draft Standard for Information Technology-Telecommunications and information exchange between systems-Local and metropolitan area networks-Specific requirements, "Part 11: Wireless LAN Medium Access Control (MAC) and Physical Layer (PHY) Specifications Amendment to IEEE P802.11-REVmc / D3.0: Fast Initial Link Setup ", IEEE, September 2014

  It is conceivable that the high-frequency radio communication cell 40 that is expected to be utilized in the future will be used as a spot cell having a small cell radius (for example, several m to 10 m). As shown in FIG. 1, the user 1 discovers the spot cell 40 while moving and uses it for high-speed communication. However, since the spot cell 40 is small and scattered in the macro cell 10, the encounter probability is not high. Conceivable. However, if the discovery is delayed, the user 1 passes through the cell coverage to some extent during the time from connection to actual communication, and therefore, if the cell is a small cell, it leads to lost use opportunities. Therefore, although it is necessary to continue scanning in the terminal, there is a dilemma that the duration of the battery is shortened because the battery is consumed if the scanning operation is always performed during movement. In the future, it is conceivable to operate three or more types of wireless interfaces such as cellular, wireless LAN, and high-frequency band access, and the problem of battery consumption will increase. Therefore, there is a need for means for efficiently performing wireless scanning.

  Therefore, it is conceivable to simply reduce the number of scans for each interface to improve the battery duration. In this case, however, there is a possibility of cell discovery delay. There is no possibility. Specifically, since a 10-meter cell passes in about 7 seconds at walking speed, if discovery takes time, the time available for communication is reduced. Also in wireless LAN scanning, channel increase due to additional allocation of 5 GHz band in the future can be considered, and increase in scanning time and battery consumption become problems. Therefore, it is necessary to scan both the wireless LAN and the high-frequency wireless cell, to reduce power consumption, and to achieve both speed of cell discovery.

  The technique described in Non-Patent Document 4 can increase the scanning speed of the wireless LAN, but does not consider the discovery of other RAT cells such as high frequencies. In addition, the point that basically all channels must be scanned remains the same. There is a need for greater efficiency to reduce power consumption.

  This invention is made | formed in view of the said situation, The place made into the objective is to provide the radio | wireless communications system which can suppress the battery consumption of a radio | wireless communication terminal.

  To achieve the above object, the present invention provides a first base station apparatus that performs wireless communication using a first wireless communication format, a first wireless communication function unit for a first wireless communication format, and a second wireless communication format. And a wireless terminal device having a second wireless communication function unit for wireless communication, the wireless communication operation information operated in the first base station device is periodically transmitted in a predetermined channel of the second wireless communication format. The wireless terminal device detects the beacon by monitoring the predetermined channel by the second wireless communication function unit, and uses the detected beacon according to the first wireless base station. When the information is included, the first wireless communication function unit is activated, and the first wireless communication function unit is wirelessly communicable with the first base station apparatus based on the operation information. Characterized by comprising control means for controlling so as to.

  The present invention further includes a second base station device that performs wireless communication using the second wireless communication format, and the beacon includes operation information of wireless communication that is operated in the second base station device, When the detected beacon includes operation information related to the second radio base station, the control means of the radio terminal device sets the second radio communication function unit and the second base station device based on the operation information. Control is performed so that wireless communication is possible.

  According to the present invention, it is not necessary to scan all channels in the terminal device having the first wireless communication function unit and the second wireless communication function unit, and it is only necessary to monitor a predetermined channel. However, it is possible to extend the battery duration. Further, the power consumption can be further reduced by keeping the first wireless communication function unit in an inactive state during monitoring of the predetermined channel.

Image diagram explaining the Multi-RAT environment Image diagram explaining the operation of a conventional terminal device Configuration diagram of high frequency RAT base station The figure explaining the cell formed by the base station of high frequency RAT An example of a wireless LAN Beacon frame Configuration diagram of wireless LAN base station The figure explaining the transmission timing of GuideBeacon Configuration diagram of terminal equipment Flowchart explaining operation of terminal device Flow chart for explaining the operation of a conventional terminal device

  An outline of a wireless communication system according to the present invention will be described with reference to the drawings. The wireless communication system includes a high frequency RAT base station 100, a wireless LAN base station 200, and a terminal device 300.

  The radio frequency RAT base station 100, as shown in FIG. 3, generates a radio LAN transmission signal having a radio frequency RAT radio base station function unit 111, a transmission unit 112 and a reception unit 113, and a function of transmitting a wireless LAN beacon signal. And a transmission output control unit 122 having a transmission output adjustment function. The high-frequency RAT radio base station function unit 111, the transmission unit 112, and the reception unit 113 are configured by a conventionally known radio communication technology such as WiGig (registered trademark).

  The wireless LAN transmission signal generation unit 121 and the transmission output control unit 122 are partially expanded based on a well-known wireless LAN technology such as the WiFi (registered trademark) standard. The wireless LAN transmission signal generation unit 121 and the transmission output control unit 122 transmit a beacon signal (hereinafter referred to as GuideBeacon) with a predetermined transmission output by a predetermined channel (hereinafter referred to as “GuideChannel”). . Here, as shown in FIG. 4, the cell radius formed by the wireless LAN beacon transmission function 120 including the wireless LAN transmission signal generation unit 121 and the transmission output control unit 122 is larger than the cell radius formed by the high frequency RAT base station function 110. Large, the former includes the latter. Here, the difference between the cell radii is the time required for the high-frequency RAT wireless communication function to transition from the inactive state to the active state, as will be described later, and the general movement of the terminal device 30. It is preferable to determine in consideration of speed (walking speed) and the like.

  The beacon signal is a signal that is commonly used in a wireless LAN and is broadcast to a terminal device to notify base station information. As GuideBeacon, an option field is provided in this technology to a beacon signal that is generally defined, and additional information is added. FIG. 5 shows an example of the configuration of GuideBeacon. As additional information, a flag indicating that it is GuideBeacon, a radio standard related to radio communication actually used in the base station, a channel, operator information, and the like are stored. It is also assumed that a plurality of information is stored because the base station may operate a plurality of wireless standards and channels. In the above-described example of the high frequency RAT, the radio standard of the high frequency RAT, its operation channel, operator information, and the like are stored.

  The wireless LAN base station 200 has a function of transmitting the GuideBeacon signal using a predetermined GuideChannel regardless of the channel that is actually operated. Here, the actually operated channel is arbitrarily selected for each base station 200 from a plurality of channels according to the surrounding radio wave environment or the like, but GuideChannel is a predetermined channel that is determined in advance. And common to a plurality of base stations 200. The wireless LAN base station 200 may use GuideChannel as an actual operation channel. In the present embodiment, a case where the guide channel and the operation channel are different will be described.

  As shown in FIG. 6, the wireless LAN base station 200 includes a wireless LAN base station function unit 210, a transmission unit 220, and a reception unit 230, for example, a general wireless LAN base such as the WiFi (registered trademark) standard. It is a station configuration. As described above, the wireless LAN base station function unit 210 has a function of transmitting a conventionally known Beacon signal in an actual operation channel.

  In the present invention, the transmission unit 220 includes the transmission signal generation unit 221 that generates the GuideBeacon, the transmission channel selection unit 222 that temporarily controls channel change from the operation channel to the GuideChannel, and the transmission that controls the transmission output of the GuideChannel. And an output control unit 223.

  FIG. 7 shows an image of transmission of a Beacon signal, switching to GuideChannel, and transmission of GuideBeacon in an actual operation channel. As illustrated in FIG. 7, the transmission channel selection unit 222 temporarily changes the channel from the operation channel to the GuideChannel at the timing when the transmission signal generation unit 221 transmits the GuideBeacon. The GuideBeacon signal describes the channel information of the wireless LAN actually operated. For example, when GuideChannel is 1ch in the 2.4 GHz band and the actual operation channel is 13ch, information on 13ch is described in GuideBeacon. In addition, when a conventional high frequency RAT base station exists in the vicinity of the base station 200 of the wireless LAN so that the cell ranges overlap, the operation information of the high frequency RAT may be described in GuideBeacon.

  As shown in FIG. 8, the terminal device 300 includes a wireless LAN communication function unit 310, a wireless LAN transmission unit 311 and reception unit 312, a high frequency RAT communication function unit 320, a high frequency RAT transmission unit 321 and reception. 322 and a control unit 330 that controls the wireless LAN communication function unit 310 and the high-frequency RAT communication function unit 320. The terminal device 300 may further include a cellular communication function unit such as LTE.

  The control unit 330 monitors the detection of the guide beacon in the guide channel by the wireless LAN communication function unit 310. When the detected guide beacon includes the operation information of the base station 200 of the wireless LAN, the control unit 330 performs wireless LAN communication based on the operation information. The functional unit 310 is controlled to be in a state where wireless communication with the base station 200 is possible. In addition, the control unit 330 normally disables the high-frequency RAT communication function, detects a guide beacon, and includes high-frequency RAT base station 100 operation information in the detected guide beacon. The RAT communication function unit is controlled to be activated. Then, the control unit 330 controls the guide beacon so that the high frequency RAT communication function unit 320 is in a wireless communicable state with the base station 100 of the high frequency RAT based on operation information of the high frequency RAT base station 100. The activated state of the high frequency RAT communication function means an operating state, the inactivated state means a power saving mode state such as power off or standby, and the object of control is the high frequency RAT communication function. It may be a whole or only a part of functions (for example, a high-frequency circuit unit such as a wireless interface).

  In this embodiment, the operation channel information is included as the operation information of the wireless LAN and the operation information of the high frequency RAT. The channel scan operation of the terminal device 300 is shown in FIG. When the terminal device 300 starts operating when the power is turned on, the wireless LAN interface turns on the power (step S1) and performs continuous scanning (steps S2 and S3). However, it is one of the characteristic points of the present invention that the channel to be searched is only a predetermined GuideChannel. The GuideChannel receives a beacon signal, recognizes that it is a GuideBeacon, searches for the channel of the wireless LAN actually operated described in the option field, and performs a connection operation (steps S4 and S5). Alternatively, when the operation in the high frequency RAT base station 100 is described in the extension field, and the power supply of the high frequency RAT interface of the terminal device 300 is OFF (or power saving mode such as standby), it is ON (active). (Step S7), the corresponding channel is searched and a connection operation is performed (Steps S8 and S9).

  According to the present invention, it is possible to suppress battery consumption due to cell scanning of the terminal device 300 including a plurality of wireless interfaces including a wireless LAN, and to extend the battery duration. That is, in the prior art, as shown in FIG. 10, each wireless interface performs an operation of searching all channels independently. However, in the present invention, the search is limited to only searching for a wireless channel GuideChannel. Scanning of a wireless LAN having a large number of channels can be reduced, and furthermore, power consumption can be reduced by turning off the power of the radio interface of the high frequency RAT.

  Further, by adjusting the transmission output of the wireless LAN beacon signal so as to cover the small cell of the high frequency RAT with an appropriate size, the interface of the high frequency band of the terminal in the vicinity of the small cell of the high frequency RAT. Can be turned on, and the user can be connected to a high-frequency RAT cell and communicated at an optimal timing.

  Furthermore, by using a wireless LAN beacon signal as an unlicensed band as a guide channel, there is an advantage that an operator can freely install a guide beacon signal transmitter.

  Although one embodiment of the present invention has been described in detail above, the present invention is not limited to this. For example, the wireless LAN and high-frequency RAT wireless standards have been described as representative examples as the wireless communication format in the above embodiment, but the wireless standards are not limited to these, and the present invention is implemented even with other wireless standards. it can. Further, the number of wireless interfaces of the terminal device is not limited to two, and the present invention can be implemented even with three or more.

  In the above embodiment, the operation environment including the high frequency RAT base station 100 and the wireless LAN base station 200 has been described. However, the operation environment including only the high frequency RAT base station 100 may be used.

DESCRIPTION OF SYMBOLS 100 ... High frequency RAT base station 111 ... High frequency RAT radio base station function part 121 ... Wireless LAN transmission signal generation part 122 ... Transmission output control part 200 ... Wireless LAN base station 210 ... Wireless LAN base station function part 220 ... Transmission part 221 ... Transmission signal generation unit 222 ... Transmission channel selection unit 223 ... Transmission output control unit 300 ... Terminal device 310 ... High-frequency RAT communication function unit 320 ... Wireless LAN communication function unit 330 ... Control unit

Claims (8)

A wireless terminal having a first base station device that performs wireless communication using the first wireless communication format, a first wireless communication function unit for the first wireless communication format, and a second wireless communication function unit for the second wireless communication format In a wireless communication system comprising a device,
Comprising an advertising means for periodically advertising the operation information of the wireless communication operated in the first base station apparatus as a beacon in a predetermined channel of the second wireless communication format;
The wireless terminal device detects the beacon by monitoring the predetermined channel by the second wireless communication function unit, and the operation information related to the first wireless base station is included in the detected beacon. And a control means for controlling the first wireless communication function unit to be in a wireless communication enabled state with the first base station apparatus based on the operation information. A wireless communication system. A second base station device that performs wireless communication using the second wireless communication format;
The beacon includes operation information of wireless communication operated in the second base station device,
When the detected beacon includes operation information related to the second radio base station, the control means of the radio terminal device sets the second radio communication function unit and the second base station device based on the operation information. The wireless communication system according to claim 1, wherein the wireless communication system is controlled to be in a wireless communication enabled state. The radio communication range of the second radio communication format formed by the advertising means includes the communicable range of the first radio communication format formed by the first base station device. Communications system. A wireless terminal having a first base station device that performs wireless communication using the first wireless communication format, a first wireless communication function unit for the first wireless communication format, and a second wireless communication function unit for the second wireless communication format A communication control method in a wireless communication system comprising a device,
Advertising means for periodically advertising the operation information of the radio communication operated in the first base station apparatus as a beacon in a predetermined channel of the second radio communication format;
When the control means of the wireless terminal device monitors the predetermined channel by the second wireless communication function unit to detect the beacon, and the detected beacon includes operation information related to the first wireless base station And a step of activating the first wireless communication function unit and controlling the first wireless communication function unit to be in a wireless communicable state with the first base station apparatus based on the operation information. A communication control method for a wireless communication system. A base station device that performs wireless communication with a wireless terminal device using a first wireless communication format,
A base station apparatus characterized by comprising advertisement means for periodically advertising at least radio communication operation information operated in its own base station apparatus as a beacon in a predetermined channel of the second radio communication format. A base station device that performs wireless communication with a wireless terminal device using a second wireless communication format,
Operation information of wireless communication operated at least in the own base station apparatus is periodically transmitted in a predetermined channel of the second wireless communication format different from the channel for communication with the wireless terminal apparatus operated in the own base station apparatus. A base station apparatus comprising an advertising means for advertising as a beacon. A wireless terminal device having a first wireless communication function unit for a first wireless communication format and a second wireless communication function unit for a second wireless communication format,
A predetermined channel in the second wireless communication format is monitored by the second wireless communication function unit, a beacon periodically advertised by the second base station device in the second wireless communication format is detected, and the detected beacon is the first When the operation information of the wireless communication related to the wireless communication format is included, the first wireless communication function unit is activated and the first wireless communication function unit is set to the operation information based on the operation information. A wireless terminal device comprising control means for controlling to be in a state capable of wireless communication with an operating first base station device. The control means operates the second wireless communication function unit with the operation information based on the operation information when the detected beacon includes operation information of wireless communication according to the second wireless communication format. The wireless terminal device according to claim 7, wherein the wireless terminal device is controlled to be in a state where wireless communication with the second base station device is possible.

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