JP2019009588A - Communication system - Google Patents

Abstract

To provide a technique capable of realizing a low traffic delay and efficient traffic accommodation in a layer-2 network.SOLUTION: A communication system according to one embodiment is so configured that a central base station and a remote base station are connected through a plurality of switches. A network controller comprises: a route selection part which selects, as a transmission route, a route whose delay time based upon a distance is equal to or less than permitted time; a band allocation part which determines a transmission band to be allocated to a radio terminal and transmission timing of data based upon a data amount of the radio terminal and first delay time of the transmission route; and an estimation part which estimates passing timing at which data passes through the respective switches in the transmission route based upon the data amount, transmission route, and transmission timing. A switch reserves a transmission band of its device at passing timing, and the central base station notifies the radio terminal of the transmission band and transmission timing determined by the network controller.SELECTED DRAWING: Figure 4

Description

  The present invention relates to traffic control in a layer 2 network.

  In order to efficiently accommodate mobile traffic, which is increasing with the spread of mobile terminals such as smartphones, in the core network, the frequency utilization efficiency is improved by arranging radio base stations at high density and making each radio base station a small cell. Consideration for improvement is underway. If the frequency utilization efficiency is improved by such a small cell size, the bandwidth capacity of the entire wireless communication system can be increased.

  On the other hand, with the increase in the number of radio base stations, the functions of the radio base stations are separated into RRH (Remote radio head) and BBU (Baseband unit: Aggregate base station), both of which are optical fibers. A technology called a mobile fronthaul that connects via a transmission line is being studied. FIG. 12 is a diagram illustrating a configuration example of a C-RAN (Centralized Radio Access Network) that is one form of the mobile fronthaul. In the C-RAN in the example of FIG. 12, BBU and RRH are connected point-to-point via an optical transmission line such as an optical fiber. In this optical transmission line, a radio signal is converted into an optical signal by CPRI (Common Public Radio Interface) and transmitted (for example, see Non-Patent Document 1).

  In addition, as shown in FIG. 13, a study of making a mobile fronthaul into a layer 2 network and sharing a plurality of BBHs and RRHs is underway in IEEE 802.1CM (for example, see Non-Patent Document 2). Furthermore, in addition to the spread of mobile terminals, sensor networks represented as a part of IoT (Internet of things) are also spreading. In such a sensor network, various sensors as IoT terminals are connected to the network according to various wireless communication standards, and information such as sensor data is collected in a server installed in the core network.

  Furthermore, a multi-service accommodation type access network that accommodates traffic such as sensor data in which a certain amount of delay is allowed and mobile traffic having a severe requirement for delay in the same layer 2 network is also being studied ( For example, refer nonpatent literature 3).

DOCOMO 5G White Paper, “Requirements and Technology Concept for 5G Wireless Access after 2020”, September 2014, URL: https://www.nttdocomo.co.jp/corporate/technology/whitepaper_5g. IEEE 802.1CM, “Time-Sensitive Networking for Fronthaul”, PAR approved 3 Sep 2015. Editor ’s draft. URL: http: //www.ieee802.0rg/1/pages/802.1cm.html. Kubo et al., "Evaluation of delay in L2 network accommodating multi-service", IEICE Society Conference 2016, B-8-25, 2016.

  However, when various services are accommodated in the same layer 2 network, protection of mobile traffic requiring low latency and efficient accommodation of low priority traffic become problems.

  In view of the above circumstances, an object of the present invention is to provide a technology capable of realizing low delay of traffic and efficient accommodation of traffic in a layer 2 network.

  According to an aspect of the present invention, an aggregation base station connected to a network controller and a remote base station are connected via a plurality of switches, and the remote terminal has a transmission band and timing notified from the aggregation base station. A communication system for transmitting data via a base station, wherein the network controller allows a first delay time based on a path distance from all paths between the aggregation base station and the remote base station to be allowed. A route selection unit that selects a route that is equal to or less than a predetermined time as a transmission route of the data, the data amount that the wireless terminal requests to transmit, and a first delay time in the transmission route that is selected by the route selection unit, A bandwidth allocation unit that determines a transmission band to be allocated to the wireless terminal and a transmission timing of the data, the data amount, and the route selection unit Therefore, the transmission path selected based on the transmission timing determined by the bandwidth allocation unit and the estimation unit for estimating the passage timing of the data passing through each switch on the transmission path, and The switch reserves the transmission band of the own device at the passage timing as a band for data transmission when the selected transmission path includes the own device, and the aggregation base station is determined by the network controller. A communication system that notifies the wireless terminal of the transmitted transmission band and the transmission timing.

  One aspect of the present invention is the communication system described above, wherein the band allocation unit is based on a transmission data amount of the wireless terminal, a first delay time in the transmission path, and a process in each device on the transmission path. A transmission band to be allocated to the wireless terminal is determined based on the second delay time.

  One aspect of the present invention is the communication system described above, wherein the route selection unit calculates an average value of the first delay time and the second delay time acquired in a predetermined period among all the routes. One communication path whose total value with the statistical value shown is equal to or less than an allowable time is selected as the data transmission path, and the bandwidth allocation unit is configured to transmit the transmission data amount of the wireless terminal and the path selection unit. The transmission band to be allocated to the wireless terminal is determined based on the total value of the first delay time and the statistical value in the transmission path selected by the above.

  One aspect of the present invention is the communication system described above, wherein the remote base station reserves the transmission band reserved for the switch when the quality of a signal received from the wireless terminal is equal to or lower than a predetermined threshold. The band allocation unit of the network controller allocates the released transmission band as a transmission band of a communication device other than the wireless terminal.

  According to the present invention, it is possible to realize a reduction in traffic delay and efficient accommodation of traffic.

It is a figure which shows the specific example of the system configuration | structure of the communication system 100 in 1st Embodiment. It is a block diagram which shows the specific example of a function structure of BBU1 in 1st Embodiment. It is a block diagram which shows the specific example of a function structure of the layer 2 switch 3 in 1st Embodiment. It is a block diagram which shows the specific example of a function structure of the network controller 4 in 1st Embodiment. FIG. 3 is a sequence diagram showing a flow of processing executed by the communication system 100 according to the first embodiment when data is transmitted from the wireless terminal 5. FIG. 3 is a sequence diagram showing a flow of processing executed by the communication system 100 according to the first embodiment when data is transmitted from the wireless terminal 5. It is a block diagram which shows the specific example of a function structure of the layer 2 switch 3a in 2nd Embodiment. It is a block diagram which shows the specific example of a function structure of the network controller 4a in 2nd Embodiment. It is a figure which shows the specific example of the system configuration | structure of the communication system 100b in 3rd Embodiment. It is a block diagram which shows the specific example of a function structure of RRH2b in 3rd Embodiment. It is a block diagram which shows the specific example of a function structure of the layer 2 switch 3b in 3rd Embodiment. It is a figure which shows the 1st specific example of the conventional communication system. It is a figure which shows the 2nd specific example of the conventional communication system.

<First Embodiment>
FIG. 1 is a diagram illustrating a specific example of a system configuration of a communication system 100 according to the first embodiment. The communication system 100 includes one or more BBU1 (Base Band Unit), one or more RRH2 (Remote Radio Head), and a plurality of layer 2 switches 3 (L2SW in the figure). A layer 2 switch network 30 and a network controller 4. FIG. 1 shows an example of one or more BBUs 1, one or more RRHs 2, and a plurality of layer 2 switches 3, respectively, BBUs 1-1 and 1-2, RRHs 2-1 and 2-2, and layer 2 switches 3-1 to 3-1. -5 is shown. BBU1 is connected to the network controller 4, and the layer 2 switch network 30 connects BBU1 and RRH2. Each device is connected by, for example, an optical fiber.

  The communication system 100 configured in this manner functions as a fronthaul line that provides connection means to a core network (not shown) for one or more wireless terminals 5 accommodated in the RRH 2. The wireless terminal 5 starts transmission of data at the transmission start timing notified from the BBU 1 and is permitted to transmit data for the transmission permission time similarly notified. The network controller 4 determines a transmission band to be allocated to the wireless terminal 5 that requests data transmission in response to an inquiry from the BBU 1. The BBU 1 responds to the requesting wireless terminal 5 with the transmission band determined by the network controller 4.

  FIG. 1 shows wireless terminals 5-1 and 5-2 as an example of one or more wireless terminals 5. The number of BBU1, RRH2, and layer 2 switch 3 provided in the communication system 100 may be different from that in FIG.

  FIG. 2 is a block diagram illustrating a specific example of a functional configuration of the BBU 1 in the first embodiment. The BBU 1 includes a first communication unit 11, a second communication unit 12, and a communication control unit 13. The first communication unit 11 is a communication interface that connects the device itself and the network controller 4. The BBU 1 communicates with the network controller 4 via the first communication unit 11. The second communication unit 12 is a communication interface that connects the own device to the layer 2 switch network 30. The BBU 1 communicates with the layer 2 switch 3-5 via the second communication unit 12.

  In response to a data transmission request from the wireless terminal 5, the communication control unit 13 inquires the network controller 4 about a transmission band and transmission timing necessary for the data transmission. The communication control unit 13 notifies the wireless terminal 5 of the transmission band and transmission timing responded from the network controller 4. Specifically, the transmission timing is a timing at which the wireless terminal 5 starts data transmission (hereinafter referred to as “transmission start timing”) and a transmission time thereof (hereinafter referred to as “transmission permitted time”).

  Specifically, the communication control unit 13 acquires a data amount (hereinafter referred to as “transmission data amount”) that the wireless terminal 5 requests to transmit based on the data transmission request of the wireless terminal 5, and determines the transmission data amount. By notifying the network controller 4, the allocation of the transmission band and transmission timing to the wireless terminal 5 is requested. Hereinafter, this request is referred to as a bandwidth allocation request. The communication control unit 13 acquires a transmission band to be allocated to the wireless terminal 5 based on a response of the network controller 4 to the band allocation request (hereinafter referred to as “band allocation response”). The communication control unit 13 controls the data transmission of the wireless terminal 5 by notifying the transmission band and the transmission timing returned from the network controller 4.

  In the band allocation response in the present embodiment, in addition to the transmission band and transmission timing, the transmission path of transmission data and the timing at which transmission data passes through each layer 2 switch 3 on the transmission path (hereinafter referred to as “passing timing”). .) Is notified. The communication control unit 13 notifies each layer 2 switch 3 constituting the layer 2 switch network 30 of the transmission path and passage timing notified from the network controller 4.

  FIG. 3 is a block diagram illustrating a specific example of a functional configuration of the layer 2 switch 3 in the first embodiment. The layer 2 switch 3 includes a first communication unit 31, a second communication unit 32, and a communication control unit 33. The 1st communication part 31 is a communication interface which connects an own apparatus and BBU1. The layer 2 switch 3 communicates with the BBU 1 via the first communication unit 31. Moreover, the 2nd communication part 32 is a communication interface which connects an own apparatus and RRH2. The layer 2 switch 3 communicates with the RRH 2 via the second communication unit 32.

  The communication control unit 33 relays communication between the RRH 2 accommodating the transmission source wireless terminal 5 and the BBU 1 by transferring the transmission data of the wireless terminal 5 through the transmission path notified from the BBU 1. Here, when the own apparatus is on the transmission path of the transmission data, the communication control unit 33 reserves (reserves) the transmission band at the passing timing notified from the BBU 1 as the transmission data transmission band. To do.

  FIG. 4 is a block diagram illustrating a specific example of a functional configuration of the network controller 4 in the first embodiment. The network controller 4 includes a communication unit 41, a delay information storage unit 42, a band allocation request processing unit 43, a route selection unit 44, a band allocation unit 45, and a passage timing estimation unit 46.

  The communication unit 41 is a communication interface that connects the device itself and the BBU 1. The network controller 4 communicates with the BBU 1 via the communication unit 41.

  The delay information storage unit 42 is configured using a storage device such as a magnetic hard disk device or a semiconductor storage device. The delay information storage unit 42 stores delay information. The delay information is information indicating the communication delay time in each path for all paths between BBU1 and RRH2. The communication delay time here is, for example, RTT (Round Trip Time). In general, a communication delay is divided into a first delay time based on a time required for a transmission path to propagate a signal and a second delay time based on a signal processing time in each communication device on the communication path. The first delay time can be estimated in advance based on the distance between the transmission paths that constitute the communication path. The second delay time can be estimated in advance based on the processing performance of each communication device. The delay information storage unit 42 stores in advance delay information indicating at least the first delay time and the second delay time. The delay information indicating the first delay time may indicate the delay time from the start point to the end point of each path, or may indicate the delay time between adjacent communication devices on each path. Also good. Further, the delay information indicating the second delay time may indicate the total processing delay in each communication device on the route, or may indicate the processing delay for each communication device. The network controller 4 may include a measurement unit (not shown) that measures the delay time in each path. In this case, the delay information stored in the delay information storage unit 42 may be updated as needed based on the measurement result of the measurement unit.

  The bandwidth allocation request processing unit 43 has a function of processing a bandwidth allocation request for BBU1. Specifically, the bandwidth allocation request processing unit 43 receives the bandwidth allocation request for BBU1 together with the transmission data amount of the wireless terminal 5, and uses the notified transmission data amount for the route selection unit 44, the bandwidth allocation unit 45, and the passage timing estimation. Notify the unit 46. The bandwidth allocation request processing unit 43 responds to the requesting BBU 1 by using the transmission band, transmission timing, transmission path, and passage timing acquired by the route selection unit 44, the band allocation unit 45, and the passage timing estimation unit 46 as a band allocation result. To do.

  The route selection unit 44 selects all the information between the BBU1 and the RRH2 based on the delay information stored in the delay information storage unit 42 and the transmission data amount of the wireless terminal 5 notified from the bandwidth allocation request processing unit 43. Among the routes, one transmission route is selected in which the delay time of the transmission data for which the wireless terminal 5 requests transmission is equal to or less than the allowable time. By this selection, a transmission path of transmission data in the layer 2 switch network 30 is determined. The route selection unit 44 notifies the selected transmission route to the band allocation unit 45, the passage timing estimation unit 46, and the band allocation request processing unit 43.

  Based on the transmission data amount of the wireless terminal 5 and the transmission route selected by the route selection unit 44, the bandwidth allocating unit 45 determines a transmission band to be assigned to data transmission of the requesting wireless terminal 5. The transmission band may be determined by any method as long as it determines a frequency band that does not compete with other data transmissions. The bandwidth allocating unit 45 notifies the determined transmission bandwidth to the bandwidth allocation request processing unit 43.

  Based on the transmission data amount of the wireless terminal 5 and the transmission route selected by the route selection unit 44, the passage timing estimation unit 46 transmits the transmission data of the wireless terminal 5 for each of the layer 2 switches 3 on the transmission route. The timing of passing through the layer 2 switch 3 (passing timing) is estimated. The passage timing estimation unit 46 notifies the band allocation request processing unit 43 of the passage timing estimated for each layer 2 switch 3 on the transmission path.

  5 and 6 are sequence diagrams illustrating a flow of processing executed by the communication system 100 according to the first embodiment when the wireless terminal 5 transmits data. First, the wireless terminal 5 transmits a data transmission request to the BBU 1 (step S101). BBU1 receives the data transmission request of the wireless terminal 5 (step S102). The communication control unit 13 of the BBU 1 identifies the transmission data amount of the wireless terminal 5 based on the received data transmission request. The communication control unit 13 transmits a bandwidth allocation request to the network controller 4 together with the identified transmission data amount (step S103).

  The network controller 4 receives the bandwidth allocation request transmitted from the BBU 1 (step S104). The bandwidth allocation request processing unit 43 of the network controller 4 receives the received bandwidth allocation request, and determines the amount of transmission data of the wireless terminal 5 received together with the bandwidth allocation request as a route selection unit 44, a bandwidth allocation unit 45, and a passage timing estimation unit. 46 is notified. The route selection unit 44 selects all the information between the BBU 1 and the RRH 2 based on the delay information stored in the delay information storage unit 42 and the transmission data amount of the wireless terminal 5 notified from the bandwidth allocation request processing unit 43. Among the routes, one transmission route is selected in which the delay time of the transmission data for which the wireless terminal 5 requests transmission is equal to or less than the allowable time (step S105). The route selection unit 44 notifies the selected transmission route to the band allocation unit 45, the passage timing estimation unit 46, and the band allocation request processing unit 43.

  Based on the transmission data amount of the wireless terminal 5 and the transmission route selected by the route selection unit 44, the bandwidth allocating unit 45 determines a transmission band to be assigned to data transmission of the requesting wireless terminal 5 (step S106). . The bandwidth allocating unit 45 notifies the determined transmission bandwidth to the bandwidth allocation request processing unit 43.

  Based on the transmission data amount of the wireless terminal 5 and the transmission route selected by the route selection unit 44, the passage timing estimation unit 46 transmits the transmission data of the wireless terminal 5 for each of the layer 2 switches 3 on the transmission route. The timing of passing through the layer 2 switch 3 (passing timing) is estimated (step S107). The passage timing estimation unit 46 notifies the band allocation request processing unit 43 of the passage timing estimated for each layer 2 switch 3 on the transmission path.

  The band allocation request processing unit 43 transmits a band allocation response indicating the transmission band, transmission timing, transmission path, and passage timing acquired by the path selection unit 44, the band allocation unit 45, and the passage timing estimation unit 46 to the requesting BBU1. (Step S108).

  BBU1 receives the band allocation response transmitted from network controller 4 (step S109). The communication control unit 13 of the BBU 1 notifies each layer 2 switch 3 of the transmission path and passage timing indicated by the received band assignment response (step S110). If the communication control unit 33 of each layer 2 switch 3 is on the notified transmission path, the communication control unit 33 reserves a transmission band at the notified passing timing (step S111). Further, the communication control unit 13 notifies the RRH 2 of the transmission path indicated by the received band assignment response (step S112).

  Further, the communication control unit 13 of the BBU 1 notifies the requesting wireless terminal 5 of the transmission band and transmission timing indicated by the received band allocation response (step S113). For example, the communication control unit 13 notifies the requesting wireless terminal 5 of the transmission band and transmission timing using downlink control information (DCI). The requesting wireless terminal 5 starts data transmission to the RRH 2 based on the transmission band and transmission timing notified from the BBU 1 (step S114).

  The RRH 2 receives the transmission data of the wireless terminal 5, and relays the received transmission data to the destination BBU 1 (step S115). Specifically, the RRH 2 performs processing such as frequency conversion, waveform shaping, A / D conversion, etc. on the radio signal received from the radio terminal 5 to convert the transmission data into a frame (hereinafter referred to as “frame” corresponding to optical transmission). This is referred to as an “optical transmission frame”. The RRH 2 sets destination information of the optical transmission frame based on the transmission path notified from the BBU 1 and outputs the optical transmission frame to the transmission path (optical fiber). Thereby, the transmission data is transmitted to the BBU 1 through the transmission path determined by the network controller 4.

  According to the communication system 100 of the first embodiment configured as described above, the transmission route is set so that the delay time of the data transmission does not exceed a predetermined allowable time in response to the data transmission request of the wireless terminal 5. Since the transmission band and the transmission timing are determined, it is possible to reduce the delay of the traffic and efficiently accommodate the traffic.

  Furthermore, according to the communication system 100 of the first embodiment, in the layer 2 switch 3 on the transmission path, a transmission band for data transmission is secured in advance before the wireless terminal 5 starts data transmission. Therefore, the wireless terminal 5 can transmit data using the BBU 1 without being affected by delay due to queuing in the layer 2 switch network 30.

Second Embodiment
The communication system 100 of the second embodiment differs from the communication system 100 of the first embodiment in that a layer 2 switch 3a is provided instead of the layer 2 switch 3 and a network controller 4a is provided instead of the network controller 4.

  FIG. 7 is a block diagram illustrating a specific example of a functional configuration of the layer 2 switch 3a in the second embodiment. The layer 2 switch 3a is different from the layer 2 switch 3 in the first embodiment in that a communication control unit 33a is provided instead of the communication control unit 33. Since the other functional units are the same as those in the first embodiment, the same reference numerals as those in FIG. The communication control unit 33a has a function of continuously notifying the network controller a of the second delay time in its own device at a predetermined timing instead of the function of reserving the transmission band based on the passing timing notified from the BBU1. .

  FIG. 8 is a block diagram illustrating a specific example of a functional configuration of the network controller 4a in the second embodiment. The network controller 4a differs from the network controller 4 in the first embodiment in that it further includes a delay amount averaging unit 47. The delay amount averaging unit 47 calculates an average value of the second delay times in a predetermined period based on the second delay times continuously notified from the layer 2 switch 3a. The delay amount averaging unit 47 stores the calculated average value of the second delay times in the delay information storage unit 42 as a part of the delay information.

  In this case, the path selection unit 44 selects a transmission path based on the delay information including the average value of the second delay time, thereby delaying based on the transmission distance of each path and the processing delay of the layer 2 switch 3a on the path. One transmission path whose total time is less than or equal to the allowable time is selected. The band allocation unit 45 and the passage timing estimation unit 46 acquire the transmission band, the transmission timing, and the passage timing based on the transmission path selected in this way.

  According to the communication system 100 of the second embodiment configured as described above, the transmission path, the transmission band, the transmission timing, and the passage timing in consideration of the processing delay in each layer 2 switch 3a are acquired. Therefore, even if the layer 2 switch 3a does not reserve a transmission band prior to data transmission of the wireless terminal 5, it becomes possible to keep the delay time within an allowable time with a certain degree of accuracy. Also in the second embodiment, the layer 2 switch 3a may reserve the transmission band based on the passage timing notified from the BBU 1 as in the first embodiment.

  In the above embodiment, an example in which the transmission path, the transmission band, the transmission timing, and the passage timing are acquired based on the average value of the second delay time is shown. However, the average value is a statistic indicating an average value to the last. These are examples of values, and they do not necessarily have to be acquired based on the average value of the second delay times. For example, the median value of the second delay time may be used, or the mode value may be used.

<Third Embodiment>
FIG. 9 is a diagram illustrating a specific example of the system configuration of the communication system 100b according to the third embodiment. The communication system 100b includes a point where the network controller 4 is connected to the layer 2 switch network 30, and an IoT (Internet of Things) device 7 (an example of a communication device other than a wireless terminal) via the access point 6 to the layer 2 switch network 30. Are different from the communication system 100 according to the first embodiment in that the RRH 2b is replaced with the RRH 2b instead of the RRH 2 and the layer 2 switch 3b is replaced with the layer 2 switch 3b. Since other configurations are the same as those in the first embodiment, the same reference numerals as those in FIG.

  FIG. 10 is a block diagram illustrating a specific example of the functional configuration of the RRH 2b in the third embodiment. The RRH 2b includes a first communication unit 21, a second communication unit 22, and a communication control unit 23. The first communication unit 21 is a communication interface that connects the device itself and the wireless terminal 5. The RRH 2 b communicates with the wireless terminal 5 via the first communication unit 21. The second communication unit 22 is a communication interface that connects the own device to the layer 2 switch network 30. The RRH 2b communicates with the layer 2 switch 3-1 via the second communication unit 22.

  The communication control unit 23 receives transmission data from the wireless terminal 5, and relays the received transmission data to the destination BBU1. The communication control unit 23 performs wireless communication with the wireless terminal 5 based on a received signal strength indicator (RSSI), a signal-to-noise ratio (SNR), a signal-to-interference noise ratio (SINR), and the like of the received signal. It has a function of acquiring a quality index value, and when the index value is equal to or less than a predetermined threshold, relaying of transmission data is stopped. In this case, the communication control unit 23 instructs the layer 2 switch 3b to release the transmission band already reserved for the canceled data transmission.

  FIG. 11 is a block diagram illustrating a specific example of a functional configuration of the layer 2 switch 3b according to the third embodiment. The layer 2 switch 3b is different from the layer 2 switch 3 in the first embodiment in that a communication control unit 33b is provided instead of the communication control unit 33. Since the other configuration is the same as that of the first embodiment, the same reference numerals as those in FIG. In addition to the functions of the communication control unit 33, the communication control unit 33b releases the reserved transmission band in accordance with an instruction from the RRH 2b. Further, when the data transmission request of the IoT device 7 is generated when the transmission band is released, the communication control unit 33b allocates the released transmission band to the data transmission of the IoT device 7.

  According to the communication system 100b of the third embodiment configured as described above, priority is given to the traffic of the wireless terminal 5 that transmits data via the RRH 2b, and the wireless communication is not generated by generating low-quality traffic. The traffic quality of the terminal 5 can be improved. Furthermore, according to the communication system 100b of the third embodiment, the transmission band assigned to the low-quality traffic is assigned to traffic having a lower priority than the traffic of the wireless terminal 5 (for example, the IoT device 7 in the present embodiment). By allocating, it is possible to realize a reduction in traffic delay and efficient accommodation of traffic.

  In the present embodiment, the IoT device 7 is shown as an example of a device that generates lower priority traffic than the wireless terminal 5, but the device accommodated in the communication system 100b is not limited to the IoT device. Any device may be accommodated. For example, a typical sensor network or the like as a part of IoT may be connected to the communication system 100b. In this embodiment, the access point 6 is shown as a device that aggregates the IoT devices 7 and connects to the communication system 100b. However, the IoT device 7 is a gateway device such as FTTH (Fiber To The Home) (generally a home gateway and the like). May be connected to the communication system 100b.

  The embodiment of the present invention has been described in detail with reference to the drawings. However, the specific configuration is not limited to this embodiment, and includes designs and the like that do not depart from the gist of the present invention.

  The present invention is applicable to a communication system including a layer 2 network.

DESCRIPTION OF SYMBOLS 100, 100b ... Communication system, 1 ... BBU (Base Band Unit: Aggregate base station), 11 ... 1st communication part, 12 ... 2nd communication part, 13 ... Communication control part, 2 ... RRH (Remote Radio Head: Remote base) Station), 21 ... first communication unit, 22 ... second communication unit, 23 ... communication control unit, 30 ... switch network, 3,3-1 to 3-5, 3a, 3b ... layer 2 switch, 31 ... first Communication unit 32 ... Second communication unit 33, 33a, 33b ... Communication control unit 4, 4a ... Network controller 41 ... Communication unit 42 ... Delay information storage unit 43 ... Bandwidth allocation request processing unit 44 ... Path Selection part 45 ... Band allocation part 46 ... Pass timing estimation part 47 ... Delay amount averaging part 5,5-1, 5-2 ... Wireless terminal 6 ... Access point 7 ... IoT (Internet of Things) machine

Claims (4)

The aggregate base station connected to the network controller and the remote base station are connected via a plurality of switches, and the wireless terminal transmits data via the remote base station at the transmission band and timing notified from the aggregate base station. A communication system for transmitting,
The network controller
A route selection unit that selects, from all routes between the aggregate base station and the remote base station, a route in which a first delay time based on a route distance is an allowable time or less as a transmission route of the data; ,
Based on the amount of data that the wireless terminal requests to transmit and the first delay time in the transmission path selected by the path selection unit, a transmission band to be allocated to the wireless terminal and a band for determining the transmission timing of the data An allocator;
Based on the data amount, the transmission path selected by the path selection unit, and the transmission timing determined by the band allocation unit, the passing timing of the data passing through each switch on the transmission path is estimated. An estimation unit;
With
The switch reserves the transmission band of the own device at the passage timing as a band for transmission of the data when the selected device includes the own transmission path,
The aggregate base station notifies the wireless terminal of the transmission band and the transmission timing determined by the network controller;
Communications system. The band allocating unit allocates the wireless terminal based on a transmission data amount of the wireless terminal, a first delay time in the transmission path, and a second delay time based on processing in each device on the transmission path. Determine the transmission band,
The communication system according to claim 1. The route selection unit has a total value of a first delay time and a statistical value indicating an average value of the second delay time acquired during a predetermined period of all the routes within an allowable time. Select one communication path as the data transmission path,
The bandwidth allocating unit is configured to perform transmission allocated to the wireless terminal based on a transmission data amount of the wireless terminal and a total value of the first delay time and the statistical value in the transmission path selected by the route selecting unit. Determine the bandwidth,
The communication system according to claim 2. The remote base station instructs the switch to release the reserved transmission band when the quality of the signal received from the wireless terminal is equal to or lower than a predetermined threshold,
The band allocation unit of the network controller allocates the released transmission band as a transmission band of a communication device other than the wireless terminal.
The communication system according to any one of claims 1 to 3.

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