JP2016208346A - Wireless communication system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To transmit/receive a control signal on a path for stably performing communication, and to transmit/receive data while adjusting the ratio of a data amount to be transmitted/received via each path by using a plurality of paths including the path.SOLUTION: In a wireless communication system for performing wireless communication by simultaneously using a plurality of communication paths, a base station 2 includes: a communication path determination part 22 for determining a communication path to be used for communication with a terminal; an optimal path determination part 23 for determining a communication path in the optimal communication situation among the determined communication paths; a ratio calculation part 24 for calculating the ratio of a data transmission amount of each of the determined communication paths; and a base station side transmission part 27 for transmitting a control signal via the determined communication path in the optimal communication situation to the terminal, and for transmitting data via the plurality of communication paths including the communication path in the optimal communication situation to the terminal on the basis of the calculated data transmission amount of each communication path. The terminal includes a terminal side reception part for receiving the control signal and the data.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a wireless communication system capable of realizing stable communication while using a plurality of communication paths to increase communication speed.

  In the field of mobile communications, traffic is increasing at an annual rate of about 1.7 times. In addition, there is a plan to start 4K and 8K resolution high-definition television broadcasts by 2020, and the need for high-resolution video viewing increases, and it is expected that the increasing trend of communication traffic will continue in the future. ing.

  On the other hand, conventional 3G and 4G communication systems cannot sufficiently accommodate traffic that is expected to increase further in the future, and are mainly used as a communication system for distributing those loads. Is being used. However, even with such a method, considering future high-definition video communication and the like, traffic cannot be accommodated sufficiently, and it has been desired to realize ultrahigh-speed data communication using millimeter waves in the 60 GHz band and the like.

  A communication system using millimeter waves is a system that can use a wide band worldwide and can perform communication of several Gbps or more. However, the communication distance is generally short, and deterioration of communication quality in non-line-of-sight communication has been a problem.

  An example of such a communication system using millimeter waves is a WiFi system compliant with IEEE 802.11ad. This system is regarded as a technical standard that assumes near field communication in a limited area such as a room, and there has been a problem in application to non-line-of-sight communication.

  For this reason, conventionally, communication systems using such millimeter waves have not been used in situations where wide area connectivity is required, and other systems represented by, for example, IEEE 802.11ac using a frequency of 6 GHz or less are used. It was.

  In addition, regarding a communication system using millimeter waves, a method for realizing high-speed communication of 10 Gbps or more by preparing a plurality of millimeter-wave wireless systems in a wireless device and simultaneously using a plurality of communication paths has been studied.

  However, when using a plurality of communication paths simultaneously, it is necessary to obtain sufficient isolation in terms of space and frequency. In particular, in order to ensure spatial isolation, it is necessary to divide the communication path spatially, and depending on the environment, the communication path becomes unforeseen.

  In this case, the communication quality becomes unstable in an unsightline communication path, and it may be difficult to exchange control signals.

  Therefore, it is necessary to develop a method for stably exchanging control signals such as synchronization signals and beacons and efficiently controlling a plurality of communication paths.

  By the way, when a communication system with a short communication distance, such as a communication system using millimeter waves, is used in mobile communication, a handover for switching a base station while moving frequently occurs, resulting in a decrease in throughput. Depending on the case, loss of control signal may occur.

  Therefore, C / U separation has been proposed as a technique for preventing loss of control signals between communication devices having a short communication distance (see Non-Patent Documents 1 and 2). Here, C represents a control plane (control signal), and U represents a user plane (user data).

  In other words, C / U separation is a technique that handles user data and control signals separately, and the control signals are transmitted to each communication device from a macro cell base station capable of wide-area communication, and stable even during handover between communication devices. The user data is transmitted / received between the communication devices while ensuring the communication control, and the throughput is reduced due to the loss of control.

KDDI demonstrates 3.5 GHz band LTE-Advanced key technology “C / U separation” http://businessnetwork.jp/Detail/tabid/65/artid/3353/Default.aspx DOCOMO 5G White Paper Requirements and Technology Concept for 5G Wireless Access after 2020

  By applying the concept of C / U separation described above to a high-speed communication system using millimeter waves or the like, it is possible to prevent a reduction in throughput caused by a loss of control and enable high-speed communication.

  In other words, control signals are transmitted / received using a path that allows stable data transmission / reception, and data communication is transmitted / received using a path that can be used as high-speed communication, although stability is reduced due to conditions such as out of sight. It is assumed that

  Specifically, in a high-speed communication system using millimeter waves, it is conceivable that the control signal is transmitted through a communication path within a line of sight where stable data transmission and reception can be performed.

  The data other than the control signal is transmitted / received in the C / U separation described above other than the communication path for the control signal. In order to enable higher-speed communication, the communication path within the line of sight is also included. It is preferable to perform transmission / reception through a plurality of communication paths.

  In order to further speed up communication in a communication system using a plurality of communication paths, it is preferable that the ratio of the amount of data transmitted and received in each communication path can be adjusted.

  Therefore, the present invention has been devised in view of the above-described problems, and transmits and receives control signals in a path that allows stable communication, and uses each path using a plurality of paths including the path. An object of the present invention is to provide a wireless communication system capable of stable high-speed communication by transmitting and receiving data while adjusting the ratio of the amount of data transmitted and received.

  A wireless communication system according to a first aspect of the present invention is a wireless communication system including a base station and a terminal that perform wireless communication using a plurality of communication paths simultaneously, wherein the base station is used for communication with the terminal. A communication path determination unit that determines a communication path, a best path determination unit that determines the communication path in the best communication state among the communication paths determined by the communication path determination unit, and the communication path determination unit A ratio calculation unit that calculates a ratio of the data transmission amount for each communication path, and a control signal is transmitted to the terminal through the communication path in the best communication state determined by the best path determination unit. And transmitting data to the terminal based on the data transmission amount for each communication path calculated by the ratio calculation unit via a plurality of communication paths including the communication path in the best communication state. It has a base station side transmitting unit that performs, the, the terminal is characterized in that it has a terminal-side receiving section for receiving the control signal and the data.

  The wireless communication system according to a second aspect of the present invention is the wireless communication system according to the first aspect, wherein the terminal is a reception state determination unit that determines a reception state of a signal transmitted from the base station, and a terminal side transmission that transmits information to the base station. The base station further includes a base station side receiving unit that receives information from the terminal, and the base station side transmitting unit of the base station transmits a beacon at the start of communication, and the terminal The reception unit receives the beacon, the reception status determination unit determines the reception status of the beacon, and the terminal-side transmission unit sends information indicating the reception status of the beacon to the base station as a response signal. Transmitting, determining the communication path by the communication path determination unit of the base station, determining the communication path in the best communication status by the best path determination unit, and the transmission path by the ratio calculation unit Calculating the ratio of the data transmission amount, characterized in that it is performed based on the information indicating the reception status to the base station is included in the response signal received.

  The wireless communication system according to a third aspect of the present invention is the wireless communication system according to the second aspect, wherein the transmission of the beacon from the transmission unit of the base station is continuously performed from the start of the communication, and the terminal side of the terminal The transmission of the response signal from the transmission unit is also performed each time the beacon is transmitted, so that the communication path determination unit of the base station determines the communication path, and the best path determination unit is in the best communication state. The determination of the communication path and the calculation of the ratio of the data transmission / reception amount for each transmission path by the ratio calculation unit are performed periodically.

  A wireless communication system according to a fourth aspect of the present invention is the wireless communication system according to any one of the first to third aspects, wherein the base station determines a modulation scheme for communication for each of the communication paths, and the communication A coding rate determining unit that determines a coding rate for each of the paths, wherein the modulation scheme determining unit and the coding rate determining unit include the reception status included in the response signal transmitted from the terminal. The modulation scheme and the coding rate are respectively determined based on information indicating the above.

  The wireless communication system according to a fifth aspect of the present invention is the wireless communication system according to any one of the second to fourth aspects, wherein the reception status determination unit of the terminal indicates the reception status for each communication path, the propagation loss of the beacon, The determination is based on at least one of a beacon delay time, a delay spread of the beacon, or a reception intensity of the beacon.

  A radio communication system according to a sixth aspect of the present invention is characterized in that, in any one of the first to fifth aspects, the base station and the terminal transmit and receive information using millimeter waves.

  According to the present invention having the above-described configuration, the control signal is transmitted and received through a path that allows stable communication, and the ratio of the amount of data transmitted and received by each path is adjusted using a plurality of paths including the path. However, stable high-speed communication is possible by transmitting and receiving data.

It is a schematic diagram which shows the radio | wireless communications system which concerns on embodiment of this invention. It is a functional block diagram of the base station used for the radio | wireless communications system which concerns on embodiment of this invention. It is a functional block diagram of the terminal used for the radio | wireless communications system which concerns on embodiment of this invention. It is a sequence flowchart which shows operation | movement of the radio | wireless communications system which concerns on embodiment of this invention.

  Hereinafter, a radio communication system as an embodiment of the present invention will be described in detail.

  FIG. 1 is a schematic diagram showing a wireless communication system 1 according to an embodiment of the present invention.

  The wireless communication system 1 according to the present embodiment is a system that performs ultrahigh-speed wireless communication using millimeter waves in the 60 GHz band, and simultaneously transmits a plurality of communication paths that are sufficiently isolated in terms of space or frequency. It is used for high-speed communication.

  The wireless communication system 1 includes a base station 1 that is a master device and a terminal 2 that is a slave device. In the wireless communication system 1 according to the present embodiment, high-speed communication using a plurality of communication paths is simultaneously performed between the base station 1 and the terminal 2.

  Here, among a plurality of communication paths used in the present embodiment shown in FIG. 1, the path A is a line of sight, and the paths B and C are non-line of sight paths.

  The line-of-sight route A is a route without an obstacle between the base station 2 and the terminal 3.

  On the other hand, the non-line-of-sight paths B and C are paths in which there are reflections and obstacles between the base station 2 and the terminal 3, and propagation loss and delay are larger than those of the line-of-sight path A.

  The route A, the route B, and the route C are in a state in which sufficient isolation is secured from each other. As a mode of securing the isolation, spatial isolation, frequency isolation, isolation using antenna directivity, isolation using path diversity, and the like are assumed.

  In FIG. 1, one base station 2 and one terminal 3 are shown. However, the present invention is not limited to this, and the base station 2 and the terminal 3 may be configured to include a plurality of base stations 2 and terminals 3, respectively. . Moreover, although the wireless communication system 1 using millimeter waves is assumed in the present embodiment, the present invention is not limited to this, and the wireless communication system 1 using another frequency band may be used.

  FIG. 2 is a functional block diagram of the base station 2 used in the wireless communication system 1 according to the embodiment of the present invention.

  The base station 2 is a communication device that becomes a master device in relation to the terminal 3.

  The base station 2 has a mechanical configuration or a function realized by a CPU (not shown) developing a control program stored in a ROM (not shown) on a RAM (not shown) and executing it. The reception unit 21 includes a communication path determination unit 22, a best path determination unit 23, a ratio calculation unit 24, a modulation scheme determination unit 25, a coding rate determination unit 26, and a base station side transmission unit 27. The base station 2 is provided with an antenna 28 used for transmitting / receiving information to / from the terminal 3.

  The base station side receiving unit 21 functions as an interface when receiving information transmitted from the terminal 3 via the antenna 28.

  The communication path determination unit 22 determines one or more communication paths that can be used for communication with the terminal 3 based on a predetermined standard.

  The best route determination unit 23 determines a communication route determined by the communication route determination unit 22 that is in the best communication state.

  The ratio calculation unit 24 calculates the ratio of the data transmission amount for each communication path determined by the communication path determination unit 22.

  The modulation method determination unit 25 determines a communication modulation method for each communication path.

  The coding rate determination unit 26 determines the coding rate for each of the communication paths.

  The base station side transmitter 27 functions as an interface for transmitting information to the terminal 3 via the antenna 28.

  The antenna 28 may be a diversity antenna in addition to a single antenna. When securing isolation of the communication paths A to C using diversity, a diversity antenna is employed as the antenna 28.

  FIG. 3 is a functional block diagram of the terminal 3 used in the wireless communication system 1 according to the embodiment of the invention.

  The terminal 3 is a device that becomes a slave device in relation to the base station 2, and is a communication device called a small cell or a femto cell that performs high-speed communication in a narrow range.

  The terminal 3 receives the terminal side as a function realized by a mechanical configuration or a CPU (not shown) expanding and executing a control program stored in a ROM (not shown) on a RAM (not shown). Unit 31, reception status determination unit 32, and terminal-side transmission unit 33. In addition, the terminal 3 is provided with an antenna 38 used for transmitting and receiving information to and from the base station 2.

  The terminal-side receiving unit 31 functions as an interface when receiving information transmitted from the base station 2 via the antenna 38.

  The reception status determination unit 32 determines the reception status of a signal transmitted from the base station using a predetermined reference.

  The terminal-side transmitter 33 functions as an interface when transmitting information to the base station 2 via the antenna 38.

  The antenna 38 may be a diversity antenna in addition to a single antenna. When securing isolation of the communication paths A to C using diversity, a diversity antenna is employed as the antenna 38.

  Next, an actual data transmission / reception operation of the wireless communication system 1 having the above-described configuration will be described.

  FIG. 4 is a sequence flowchart showing the operation of the wireless communication system according to the embodiment of the present invention.

  First, at the start of communication, the base station side transmitter 21 of the base station 2 broadcasts a beacon through a plurality of communication paths A, B, and C via the antenna 28 (step S21).

  The broadcasted beacon is received by the terminal side receiving unit 31 of the terminal 3 via the antenna 38 (step S31).

  Next, the reception status determination unit 32 of the terminal 3 determines the beacon reception status for each of the communication paths A, B, and C (step S32).

  Specifically, the reception status determination unit 32 sets the beacon reception status for each of the communication paths A, B, and C to at least one of beacon propagation loss, beacon delay time, beacon delay spread, or beacon reception intensity. This is performed based on the detected value.

  That is, the reception status determination unit 32 determines these detection values by comparing them with a predetermined threshold or by comparing the communication paths A, B, and C.

  Next, the terminal side transmission unit 33 of the terminal 3 transmits a response signal including the determination result by the reception state determination unit 32 to the base station 2 using the antenna 38 (step S33).

  Next, the base station side receiver 21 of the base station 2 receives a response signal from the terminal 3 via the antenna 28 (step S22).

  Next, the communication path determination unit 22 of the base station 2 determines the communication path used for communication with the base station 2 based on the reception status determination result for each communication path included in the response signal transmitted from the terminal 3. This is performed (step S23).

  In this embodiment, the communication path to be used is determined by comparing the reception status determination result for the predetermined item described above with a predetermined threshold value set in advance for the corresponding item. This is done by adopting a good communication path as the communication path.

  In the present embodiment, since all of the communication paths A to C shown in FIG. 1 exceed a predetermined threshold for a predetermined evaluation item, they are adopted as communication paths that are actually used for communication.

  In the present embodiment, three communication paths A to C are used, but the present invention is not limited to this, and any two or more communication paths are used.

  Next, the best route determination unit 23 of the base station 2 determines a route in the best communication state from among the communication routes determined to be used for communication by the communication route determination unit 22 (step S34).

  In the present embodiment, since the communication path A that is the line-of-sight path is in the best communication state, the best path determination unit 23 determines that this is the best communication path.

  The communication path A determined to be the best communication path here is used not only for normal data transmission / reception, but also for transmission / reception of control signals, as will be described later.

  In the present embodiment, the best communication path A is the only prospective path, but in the present invention, the communication path A is not limited to this and may be the one having the best communication environment among the communication paths determined in step S23. For example, even a communication path that is out of sight may be adopted.

  Next, the ratio calculation unit 24 of the base station 2 calculates the ratio of the data transmission amount for each of the communication paths A to C determined by the communication path determination unit 22 (step S25).

  The ratio calculation unit 24 increases the ratio of the data transmission amount for a communication path with good communication status, and decreases the ratio of the data transmission amount for a communication path with poor communication status. This ratio is calculated based on the determination result of the communication status included in the response signal transmitted from the terminal 3.

  In addition, the ratio calculation unit 24 uses the ratio of the data amount of the control signal so as to be used for transmission / reception of the control signal for the communication path with the best communication condition even in the best communication condition. Calculate by subtracting.

  Next, the modulation scheme determination unit 25 of the base station 2 determines a modulation scheme in transmission / reception of information with the terminal 3 (step S26).

  Next, the coding rate determination unit 26 of the base station 2 determines the coding rate in transmission / reception of information with the terminal 3 (step S27).

  Next, the base station side transmission unit 21 of the base station 2 transmits a control signal to the terminal 3 via the antenna 28. This control signal is transmitted using the best communication path A found as a result of the determination by the best path determination unit 23 (step S28). This control signal is transmitted as a beacon in this embodiment.

  The control signal includes a synchronization signal, information on a modulation scheme, information on a coding rate, and the like.

  Next, the terminal side receiver 31 of the terminal 3 receives the control signal via the antenna 38 (step S34).

  Next, based on the received control signal, the terminal 3 executes its own control operation such as synchronization with the base station 2 to enable transmission / reception of data other than the control signal to / from the base station 2 ( Step S35).

  Next, the base station side transmitter 27 of the base station 2 transmits data other than the control signal to the terminal 3 via the antenna 28 (step S29). Then, the base station 2 ends the operation.

  The data transmission timing is performed according to, for example, the data transmission timing included in the previously transmitted control signal, and the terminal 3 performs data transmission / reception by performing standby based on the timing.

  Further, this data transmission is performed using a plurality of (three in the present embodiment) transmission paths A to C including the transmission path A through which the control signal is transmitted as described above.

  Further, the data transmission / reception amount for each of the communication paths A to C is performed based on the ratio determined by the ratio calculation unit 24 as described above.

  Also, the data modulation scheme and coding rate for each of the communication paths A to C are determined by the modulation scheme determining unit 25 and the coding rate determining unit 26, and data is transmitted and received. .

  Next, the terminal-side receiving unit 31 of the terminal 3 receives the data transmitted from the base station 2 via the antenna 38 (step S36). The terminal 3 performs a predetermined operation based on the received data, and then ends the operation.

  As described above, according to the wireless communication system 1 according to the present invention, the control signal is transmitted / received through a route that allows stable communication, and the amount of data transmitted / received through each route using a plurality of routes including the route is also determined. Stable and high-speed communication is possible by transmitting and receiving data while adjusting the ratio.

  In the above-described embodiment, transmission of a beacon that is not a control signal from the base station 2 is performed only once (step S21). However, the present invention is not limited to this, and is repeatedly performed at a predetermined interval. It may be.

  In this case, every time a beacon is transmitted at the start of connection, the above-described steps S22 to S28 on the base station 2 side and steps S31 to S35 on the terminal 3 side are executed to transmit a communication route or a control signal to be used. The transmission / reception of data is performed while updating the communication status to the optimum one each time, such as determination of the modulation method and coding rate.

  In this way, by repeating the beacon transmission and determining the best route each time, control signals are not exchanged on the communication route where the communication status becomes unstable, and more stable and faster data transmission / reception is possible. Will be able to do.

  In addition, when a situation in which the beacon of the control signal cannot be received periodically occurs, the search operation of each communication path (steps S21 to S22, steps S31 to S33) is resumed after a certain period. Also good.

  In the above-described embodiment, the modulation scheme determining unit 25 and the coding rate determining unit 26 are provided. However, in the present invention, these configurations are not indispensable, and a predetermined modulation scheme and encoding are determined. It is also possible to perform communication at a rate.

  Moreover, although the radio | wireless communications system 1 which concerns on this embodiment mentioned above was a system which performs super-high-speed radio | wireless communication using the millimeter wave of 60 GHz band, this invention is not limited to this, Communication using another frequency band It may be a system.

  In the above-described embodiment, the communication path determination unit 22 determines the communication path in step S23 based on the reception status determination result for each communication path included in the response signal transmitted from the terminal 3.

  However, the present invention is not limited to this, and a mode in which the communication path determination unit 22 determines a plurality of communication paths set in advance by the user and stored in a storage unit (not shown) may be used.

DESCRIPTION OF SYMBOLS 1 Wireless communication system 2 Base station 3 Terminal 21 Base station side transmission part 22 Communication path determination part 23 Best path determination part 24 Ratio calculation part 25 Modulation system determination part 26 Coding rate determination part 27 Base station side transmission part 28 Antenna 31 Terminal Side receiving unit 32 reception status determining unit 33 terminal side transmitting unit 38 antenna

Claims (6)

A wireless communication system including a base station and a terminal that perform wireless communication using a plurality of communication paths simultaneously,
The base station
A communication path determination unit that determines the communication path used for communication with the terminal;
A best route determination unit for determining the communication route in the best communication state among the communication routes determined by the communication route determination unit;
A ratio calculation unit that calculates a ratio of the data transmission amount for each communication path determined by the communication path determination unit;
A control signal is transmitted to the terminal through the communication path in the best communication state determined by the best path determination unit, and through a plurality of communication paths including the communication path in the best communication state. A base station side transmission unit that transmits data to the terminal based on the data transmission amount for each communication path calculated by the ratio calculation unit;
Have
The wireless communication system, wherein the terminal includes a terminal-side receiving unit that receives the control signal and the data. The terminal
A reception status determination unit that determines the reception status of a signal transmitted from the base station;
A terminal-side transmitter that transmits information to the base station;
Further comprising
The base station
A base station receiving unit for receiving information from the terminal;
The base station side transmitter of the base station transmits a beacon at the start of communication,
The reception unit of the terminal receives the beacon, the reception status determination unit determines the reception status of the beacon, and the terminal side transmission unit uses the information indicating the reception status of the beacon as a response signal as the response signal. To the station,
Determination of the communication path by the communication path determination unit of the base station, determination of the communication path in the best communication state by the best path determination unit, and ratio of data transmission / reception amount for each transmission path by the ratio calculation unit The wireless communication system according to claim 1, wherein the calculation is performed based on information indicating the reception status included in the response signal received by the base station.   Transmission of the beacon from the transmission unit of the base station is continuously performed from the start of communication, and transmission of the response signal from the terminal-side transmission unit of the terminal is also performed every time the beacon is transmitted. The communication path determination unit of the base station determines the communication path, the best path determination unit determines the communication path in the best communication state, and the ratio calculation unit for each transmission path The wireless communication system according to claim 2, wherein the ratio of the data transmission / reception amount is periodically calculated. The base station
A modulation scheme determining unit that determines a modulation scheme of communication for each of the communication paths;
A coding rate determination unit that determines a coding rate for each of the communication paths;
Further comprising
The modulation scheme determining unit and the coding rate determining unit determine the modulation scheme and the coding rate, respectively, based on information indicating the reception status included in a response signal transmitted from the terminal. The wireless communication system according to any one of claims 1 to 3.   The reception status determination unit of the terminal determines the reception status for each communication path based on at least one of the propagation loss of the beacon, the delay time of the beacon, the delay spread of the beacon, or the reception strength of the beacon. The wireless communication system according to claim 2, wherein the wireless communication system is a wireless communication system.   The wireless communication system according to claim 1, wherein the base station and the terminal transmit and receive information using millimeter waves.

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