JP6473324B2 - Optical wireless communication system, traffic control method in optical wireless communication system, and communication apparatus - Google Patents

Description

  The present invention relates to an optical wireless communication system and a traffic transmission control method in an optical wireless communication system.

  1 to 4 show an example of a configuration in which a passive optical network and a wireless LAN network are connected as an optical wireless communication system related to the present invention. In the passive optical network related to the present invention, an optical line terminal (OLT) 92 includes a plurality of optical network unit (ONU) 93, an optical fiber transmission line, and a one-to-n transmission line. There are a PON (Passive Optical Network) method in which point-to-multipoint communication is performed via an optical splitter (n is a natural number), and an SS (Single Star) method in which the OLT 92 and the ONU 93 perform one-to-one communication. Here, the OLT 92 is connected to, for example, a service network (not shown) that is an upper network.

  The wireless LAN network is a network for connecting the wireless LAN terminal 91 to a wireless LAN access point (AP) 95 under the control of the ONU 93 as shown in FIGS. 1 to 4, and the ONU 93 and the AP 95 are connected as shown in FIGS. There is a configuration in which the ONU 93 and the AP 95 are connected in a 1-to-n manner as shown in FIGS. As a representative standard of gigabit class PON, as EPON (Ethernet (registered trademark) PON) standardized by IEEE 802.3ah task force, 10 gigabit class PON standardized by IEEE 802.3av task force There is 10G-EPON. As a typical wireless LAN standard, there is IEEE 802.11n in which specifications for performing communication in the 2.4 GHz band or the 5 GHz band are defined.

  FIG. 5 shows a functional block diagram of the OLT 92 in the EPON related to the present invention. The OLT 92 related to the present invention includes an SNI (Service Node Interface) 24, a queue management unit 23, a PON signal processing unit 22, and a PON-IF (PON Interface) 21. The downlink main signal flows to the PON-IF 21 via the SNI 24, the queue management unit 23, and the PON signal processing unit 22. On the other hand, the upstream main signal flows to the SNI 24 via the PON-IF 21, the PON signal processing unit 22, and the queue management unit 23. Here, uplink is a direction from the wireless LAN terminal 91 to the OLT 92, and downlink is a direction from the OLT 92 to the wireless LAN terminal 91.

  The PON signal processing unit 22 of the OLT 92 causes the ONU 93 to report the amount of data in the queue provided in the ONU 93, and the queue data in the ONU 93 based on the report message received from the ONU 93. It has DBA (Dynamic Bandwidth Allocation) for monitoring the amount and assigning a specification band to each ONU 93, and OAM (Operations, Administration, and Maintenance) for exchanging control frames for maintenance monitoring with the ONU 93.

  FIG. 6 shows a functional block diagram of the AP 95 related to the present invention. The AP 95 related to the present invention includes a PHY (Physical Layer) port 54, a queue management unit 53, a radio frame generation / conversion unit 52, and an antenna 51. The downlink main signal flows to the antenna 51 through the PHY port 54, the queue management unit 53, and the radio frame generation / conversion unit 52. On the other hand, the upstream main signal flows to the PHY port 54 via the antenna 51, the radio frame generation / conversion unit 52, and the queue management unit 53.

  In recent years, as an alternative to the rapid increase in traffic due to the spread of wireless LANs and the spread of smartphones in homes, offloading of traffic for load distribution has been performed by using wireless LANs to access external networks. For this reason, the number of public wireless LAN spots installed is also increasing. Under such a usage environment, a large number of wireless LAN terminals 91 are overcrowded in a closed space.

  Here, there are cases where the cover areas of a plurality of APs 95 overlap and a plurality of wireless LAN terminals 91 exist in the overlapping part. For example, in FIG. 2, the cover areas of AP95 # 1 and AP95 # 2 overlap, and the wireless LAN terminal 91 # 2 and the wireless LAN terminal 91 # 3 are arranged in the overlapping portion. In such a case, if a plurality of APs 95 and a plurality of wireless LAN terminals 91 share the same frequency channel and try to communicate at the same time, collisions are likely to occur in communication by those APs 95 and wireless LAN terminals 91. There was a problem that the quality of wireless communication was likely to deteriorate. Here, the deterioration of the wireless communication quality is, for example, a decrease in throughput, an increase in delay, or occurrence of connection failure.

Technology basic course "GE-PON technology 4th GE-PON systematization function", NTT Technical Journal, November 2005, pp. 59-61. IEEE Standard 802.11, Wireless LAN medium access control (MAC) and Physical layer (PHY) specification, 12 June, 2007. Issues in wireless dense environment due to wireless LAN offload, IEICE-CQ2012-46, IEICE-MoMu2012-27.

  An object of the present invention is to prevent degradation of wireless communication quality when a plurality of wireless LAN access points exist so as to share a communication area and a plurality of wireless LAN terminals exist in the shared communication area. To do.

  In order to achieve the above object, an optical wireless communication system and a traffic control method according to the present invention provide a wireless device generated by a wireless LAN access point or the like in a communication device such as an OLT installed above a wireless LAN access point or the like. Based on information relating to wireless communication between the LAN access point and the wireless LAN terminal, the transmission timing of downlink traffic is determined, and communication control of downlink traffic is performed.

  Specifically, the optical wireless communication system of the present invention is an optical wireless communication system in which a wireless base station that performs wireless communication with a wireless terminal is connected to a communication device on the upper side of the wireless base station, the communication device Is a management table in which information related to radio communication between the radio base station and the radio terminal is described, and information in the management table and observation of downlink traffic to the radio terminal flowing into the communication device Communication using the result to determine a transmission permission time zone indicating transmission timing at which the radio base station transmits the downlink traffic to the radio terminal, and to transmit the downlink traffic to the radio base station according to the transmission permission time zone A wireless transmission device that transmits the downlink traffic received from the communication device to the wireless terminal. The earth station transmission control unit includes.

  Specifically, the optical wireless communication system of the present invention is an optical wireless communication system in which a wireless base station that performs wireless communication with a wireless terminal is connected to a communication device on the upper side of the wireless base station, the communication device Is a management table in which information related to radio communication between the radio base station and the radio terminal is described, and information in the management table and observation of downlink traffic to the radio terminal flowing into the communication device Communication using the result to determine a transmission permission time zone indicating transmission timing at which the radio base station transmits the downlink traffic to the radio terminal, and to transmit the downlink traffic and the transmission permission time zone to the radio base station An apparatus-side transmission control unit, wherein the radio base station transmits the downlink traffic received from the communication apparatus in advance according to the transmission permission time zone. The radio base station side transmission control unit that transmits to the radio terminal, comprising.

  In the optical wireless communication system of the present invention, the wireless base station creates a table in which information relating to wireless communication between the wireless base station and the wireless terminal is described based on a request signal from the wireless terminal The radio base station side transmission control unit further transmits a table created by the table creation unit to the communication device, and the communication device receives the table received from the radio base station. A management table adding unit that updates the management table by adding to the management table may be further included.

  Specifically, the traffic control method in the optical wireless communication system is a traffic control method in an optical wireless communication system in which a wireless base station that performs wireless communication with a wireless terminal is connected to a communication device on the upper side of the wireless base station. Then, the communication device uses a management table in which information related to wireless communication between the wireless base station and the wireless terminal is described, and an observation result of downlink traffic to the wireless terminal flowing into the communication device, A transmission permission time zone determination procedure for determining a transmission permission time zone indicating a transmission timing at which the radio base station transmits the downlink traffic to the radio terminal; and the communication device transmits the downlink traffic according to the transmission permission time zone. The downlink traffic transmitted to the base station or received from the communication device by the radio base station And a transmission step of transmitting to the wireless terminal in accordance with the transmission permitted period in order.

  According to the present invention, when a plurality of wireless LAN access points exist so as to share a communication area, and a plurality of wireless LAN terminals exist in the shared communication area, it is possible to prevent deterioration in wireless communication quality. it can.

1 shows a first example of an optical wireless communication system related to the present invention. The 2nd example of the optical wireless communication system relevant to this invention is shown. 3 shows a third example of an optical wireless communication system related to the present invention. 4 shows a fourth example of an optical wireless communication system related to the present invention. An example of OLT relevant to this invention is shown. An example of AP relevant to this invention is shown. An example of OLT concerning Embodiment 1 of the present invention is shown. An example of AP which concerns on Embodiment 1 of this invention is shown. An example of the cover area of AP which concerns on Embodiment 1 of this invention is shown. An example of the sequence of the traffic control method which concerns on Embodiment 1 of this invention is shown. An example of the table which concerns on Embodiment 1 of this invention is shown. An example of the management table which concerns on Embodiment 1 of this invention is shown. An example of the transmission timing of the downlink traffic which concerns on Embodiment 1 of this invention is shown. An example of the sequence of the traffic control method which concerns on Embodiment 2 of this invention is shown. An example of the transmission timing of the downlink traffic which concerns on Embodiment 2 of this invention is shown. An example of the cover area of AP which concerns on Embodiment 3 of this invention is shown. An example of the table which concerns on Embodiment 3 of this invention is shown. An example of the management table which concerns on Embodiment 3 of this invention is shown. An example of the transmission timing of the downlink traffic which concerns on Embodiment 3 of this invention is shown.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In addition, this invention is not limited to embodiment shown below. These embodiments are merely examples, and the present invention can be implemented in various modifications and improvements based on the knowledge of those skilled in the art. In the present specification and drawings, the same reference numerals denote the same components.

(Embodiment 1)
[Optical wireless communication system]
The optical wireless communication system according to the present embodiment includes a station-side terminal device (OLT) 92, an optical subscriber terminal device (ONU) 93, a wireless LAN access point (AP) 95, and a wireless LAN terminal 91. The OLT 92 functions as a communication device, the AP 95 functions as a wireless base station, and the wireless LAN terminal 91 functions as a wireless terminal. In the present embodiment, the OLT 92, the ONU 93, the AP 95, and the wireless LAN terminal 91 are connected as shown in FIGS. At that time, as shown in FIG. 1 and FIG. 3, the AP 95 may be connected in a one-to-one relationship under the ONU 93, and as shown in FIG. 2 and FIG. 4, one-to-n (n is a natural number) under the ONU 93. ), The AP 95 may be connected.

[Function blocks of OLT]
FIG. 7 shows a functional block of the station side termination device (OLT) 92 according to the present embodiment. In addition to the functional blocks of the OLT 92 related to the present invention shown in FIG. 5, the OLT 92 according to the present embodiment is notified from the observation unit 28 that observes the traffic flowing into the queue management unit 23, the timer 29, and the AP 95. Management unit 27 that performs calculation based on information described in the management table created from the table related to wireless communication status and information related to downlink traffic, and management in which new information is added to the table related to wireless communication status notified from AP 95 A management table adding unit 25 for managing the table, and a control signal generating unit 26 for determining a transmission permission time zone indicating the transmission timing of the downlink traffic to the wireless LAN terminal 91 are provided. The PON signal processing unit 22, the management table addition unit 25, the control signal generation unit 26, the calculation unit 27, the observation unit 28, and the timer 29 function as a communication device side transmission control unit.

[Function block of AP]
FIG. 8 shows functional blocks of a wireless access point (AP) 95 according to this embodiment. In addition to the functional blocks of the AP 95 related to the present invention shown in FIG. In the present embodiment, the radio frame generation / conversion unit 52 functions as a radio base station side transmission control unit.

  In the present embodiment, the OLT 92 as a communication device connected to a higher level than the AP 95 determines a transmission permission time zone indicating the transmission timing of the downlink traffic based on the information related to the wireless communication status notified from the AP 95, and the OLT 92 Controls transmission of downlink traffic to the AP 95 in accordance with the transmission permission time zone. In the optical wireless communication network according to the present embodiment, ONUs 93 # 1 to # 3 are connected under the same OLT 92, AP95s are connected to each of the ONUs 93 # 1 to # 3 in a one-to-one relationship, A wireless LAN terminal 91 is connected in a one-to-one relationship. The numbers of the APs 95 are # 1 to # 3, and the wireless LAN terminal 91 is similarly # 1 to # 3.

  FIG. 9 shows the coverage area of the wireless LAN network of AP95 # 1 to # 3. Here, A1 is the cover area of AP95 # 1, A2 is the cover area of AP95 # 2, and A3 is the cover area of AP95 # 3. As shown in FIG. 9, the wireless LAN cover areas A1, A2, and A3 of AP95 # 1 to # 3 overlap. In this embodiment, when the wireless LAN terminal 91 exists in the overlapping part of the cover area of each AP 95 as shown in FIG. 9, the transmission of the downlink traffic to the wireless LAN terminal 91 existing in the overlapping part of the cover area is one. AP95 does it. While the AP 95 is transmitting the downlink traffic, the other APs 95 that constitute the overlapping cover area do not transmit the downlink traffic.

  FIG. 10 shows a series of sequences relating to the traffic control method in the present embodiment. The traffic control method according to the present embodiment includes a transmission permission time zone determination procedure and a transmission procedure in order. A management table creation procedure may further be included before the transmission permission time zone determination procedure. In the management table creation procedure, the AP 95 creates a table in which information related to the wireless communication status transmitted by the AP 95 to the OLT 92 is collected, and the OLT 92 creates a management table based on the table. In the transmission permission time zone determination procedure, the traffic transmission permission time zone in the OLT 92 is calculated. Here, the AP 95 is, for example, AP 95 # 1, and the wireless LAN terminal 91 is, for example, the wireless LAN terminal 91 # 1. In the transmission procedure, the OLT 92 transmits downlink traffic based on the transmission permission time zone.

  In the management table creation procedure according to the present embodiment, first, the wireless frame generation / conversion unit 52 of the AP 95 # 1 sends a wireless communication status inquiry to the wireless LAN terminal 91 # 1 connected to the AP 95 # 1 via the antenna 51. A command relating to the match is transmitted (S101). Next, the wireless frame generation / conversion unit 52 of AP95 # 1 receives the wireless communication status response information from the wireless LAN terminal 91 # 1 (S102). Next, the table creation unit 55 of AP95 # 1 creates a table based on the obtained wireless communication status response information, and transmits the table to the OLT 92 via the queue management unit 53 and the PHY port 54 (S103). The OLT 92 creates a management table based on the table received from the AP 95.

In the transmission permission time zone determination procedure according to this embodiment, the control signal generation unit 26 of the OLT 92 is based on the management table created based on the table transmitted from the AP95 # 1 and the observation information of the downlink traffic in the OLT 92. Determine the transmission permission time zone.
In the transmission procedure according to the present embodiment, the PON signal processing unit 22 of the OLT 92 transmits downlink traffic to the AP 95 # 1 in accordance with the transmission permission time zone for the wireless LAN terminal 91 # 1 (S104). The radio frame generation / conversion unit 52 of the AP 95 # 1 transmits the downlink traffic received from the OLT 92 to the wireless LAN terminal 91 # 1 (S105).
A management table creation procedure for creating a management table in which information related to the wireless communication status transmitted by the AP 95 to the OLT 92 in this embodiment is collected, and a traffic transmission permission time zone calculation procedure in the OLT 92 will be described in this order.

[Management table creation procedure]
In the management table creation procedure according to this embodiment, the AP 95 collects information between the AP 95 and the wireless LAN terminal 91 connected to the AP 95 and creates a table relating to the wireless communication status. First, the wireless frame generation / conversion unit 52 of the AP 95 # 1 acquires in advance an ID or MAC address that is the attribution number of the wireless LAN terminal 91 connected to the AP 95 # 1 via the wireless LAN network. These pieces of information can be acquired when the wireless LAN terminal 91 connects to the AP 95 for association.

  The radio frame generation / conversion unit 52 of AP95 # 1 notifies the information acquired in advance and the channel used by AP95 # 1 to the table creation unit 55, and the table creation unit 55 enters the notified information in the table. Next, the wireless frame generation / conversion unit 52 receives a wireless data frame defined by the IEEE 802.11 standard from the wireless LAN terminal 91 # 1 connected to the AP 95 # 1. The wireless data frame received by the wireless frame generation / conversion unit 52 includes a header related to communication. In the structure of the PHY header of the IEEE 802.11 standard, for example, information related to a wireless transmission rate transmitted in the wireless data frame is described in the Rate field. Therefore, the wireless frame generation / conversion unit 52 stores the information. The table creation unit 55 creates a table by associating the information with the ID or MAC address of the wireless LAN terminal 91 that is the transmission source of the wireless data frame. It returns to the radio frame generation / conversion unit 52.

  FIG. 11 shows the tables created by the table creation unit 55 of APs # 1 to # 3 in this embodiment. Here, each of AP # 1 to # 3 is AP95. Each of the radio frame generation / conversion units 52 of APs # 1 to # 3 transmits the created table to the OLT 92 via the queue management unit 53 and the PHY port 54. These operations are similarly performed by other APs 95. The management table adding unit 25 of the OLT 92 creates a management table based on the table received from the AP 95.

  In addition to the wireless transmission rate, the number of retransmissions generated by the wireless frame generation / conversion unit 52 of the AP 95 in communication with the wireless LAN terminal 91 may be used as information described in the table. The information described in the table may describe an average value of values obtained by measuring for a certain period, or may be a maximum value or a minimum value. Further, the table creation unit 55 of the AP 95 may write information obtained from a request that is a request signal from the wireless LAN terminal 91 in a table. The table creation unit 55 may create a table based on a request from the wireless LAN terminal 91. The request is, for example, the type of application used by the wireless LAN terminal 91, the requested speed, the requested bandwidth, or the requested delay. The table creation unit 55 of the AP 95 writes part or all of the information in the table. When the wireless LAN terminal 91 transmits a request to the AP 95, the wireless LAN terminal 91 may transmit the request itself, or may wait for an instruction from the AP 95 before transmitting.

[Procedure for transmission permission time zone]
In the transmission permission time zone determination procedure according to the present embodiment, the control signal generation unit 26 of the OLT 92 creates the wireless communication status table received from the AP 95 and updates it using the observation result of the downlink traffic in the queue management unit 23. Based on the management table, a transmission permission time zone indicating the transmission timing of the downlink traffic is determined.

  First, the observation unit 28 observes the destination and traffic amount of traffic flowing into the queue management unit 23 in the OLT 92 at a predetermined time T. A timer 29 is used for measuring the fixed time T. The destination of the traffic is, for example, the wireless LAN terminal 91 # 1. The observation unit 28 transmits the observed information to the management table addition unit 25, and the management table addition unit 25 receives the management table created from the wireless communication status table transmitted from the AP 95 from the observation unit 28. Update by adding the information.

  Next, the calculation unit 27 calculates the time required for transmission from the AP 95 to the wireless LAN terminal 91 from the traffic amount observed by the observation unit 28 and the wireless transmission rate described in the management table transmitted from the AP 95. Approximate and transmit the information to the management table adding unit 25. The management table adding unit 25 adds the information sent from the calculation unit 27 to the management table and updates it. FIG. 12 shows a management table of AP95 # 1 to # 3 updated by the management table adding unit 25 in the OLT 92. The control signal generation unit 26 of the OLT 92 determines the transmission permission time zone with reference to the estimated transmission time for each AP95 # 1 to # 3 in the management table. The PON signal processing unit 22 transmits downlink traffic for each AP 95 based on the transmission permission time zone determined by the transmission permission time zone determination procedure. Here, the OLT 92 may transmit downlink traffic to all APs 95, and each of the APs 95 may extract only downlink traffic destined for the own AP 95.

  A series of operations of the OLT 92 and traffic transmission timing to the AP 95 # 1 to # 3 will be described with reference to FIG. First, when the OLT 92 receives a table from the AP 95, the observation unit 28 observes the amount of traffic transmitted to the AP 95 # 1 to # 3 in the queue management unit 23 of the OLT 92 between t0 and t1.

  Next, the calculation unit 27 transmits information from the AP 95 # 1 to # 3 to the wireless LAN terminals 91 # 1 to # 3 based on information on the traffic volume and the wireless transmission rate in the management table between t1 and t2. The estimated transmission time is calculated, and the management table stored in the management table adding unit 25 is updated. When calculating the estimated transmission time, for example, overhead such as transmission delay and processing delay in each communication terminal may be considered. The control signal generation unit 26 determines a transmission permission time zone in the AP 95 # 1 to # 3 from the updated management table.

[Sending procedure]
In the transmission procedure according to the present embodiment, the PON signal processing unit 22 transmits downlink traffic to the AP 95 # 1 between t2 and t3 based on the information related to the determined transmission permission time zone. The wireless frame generation / conversion unit 52 of AP95 # 1 transmits traffic from the antenna 51 of AP95 # 1 to the wireless LAN terminal 91 # 1 between t3 and t5. In addition, the PON signal processing unit 22 of the OLT 92 allows the AP95 # 2 radio frame generation / conversion unit 52 to transmit traffic between t5 and t7, which is the AP95 # 2 transmission permission time zone, between t4 and t5. The downstream traffic is transmitted to AP95 # 2. The radio frame generation / conversion unit 52 of AP95 # 2 transmits downlink traffic to the wireless LAN terminal 91 # 2 between t5 and t7. Further, the PON signal processing unit 22 of the OLT 92 transmits the downlink traffic to the AP95 # 3 between t6 and t7 so that the AP95 # 3 can transmit the downlink traffic in the transmission time zone of the AP95 # 3. The radio frame generation / conversion unit 52 of AP95 # 3 transmits downlink traffic to the wireless LAN terminal 91 # 3 between t7 and t8.

  In the present embodiment, the OLT 92 is described as an example of the communication device connected to the upper side of the AP 95, but the communication device may be the ONU 93. The observation unit 28 observes the amount of traffic flowing into the queue management unit 23 in the OLT 92 at a certain time T by the timer 29, but observes the average value and average rate of the traffic amount flowing at the certain time T. Also good. In this embodiment, the transmission order from the OLT 92 to the AP 95 # 1 to # 3 is the order of the AP 95 # 1 to # 3. However, the transmission order is not limited to this.

  In the present embodiment, the OLT 92 determines a downlink traffic transmission permission time zone based on information related to the wireless communication status notified from the AP 95, and the OLT 92 controls the downlink traffic transmission control to the AP 95 according to the transmission permission time zone. By performing this, the wireless communication quality in the wireless LAN system can be improved. In addition, since the AP 95 in this embodiment does not require an additional function as compared with the configuration of the existing device, a general-purpose device can be used.

(Embodiment 2)
In this embodiment, the OLT 92 notifies the information from the OLT 92 to the AP 95 after determining the transmission permission time zone indicating the transmission timing for transmitting the downlink traffic. Specifically, the OLT 92 as a communication device connected to a higher level than the AP 95 determines a transmission permitted time zone for downlink traffic based on information on the wireless communication status notified from the AP 95. The OLT 92 notifies the AP 95 of information related to the transmission permission time zone, and the AP 95 controls transmission of downlink traffic based on the information.

  In this embodiment, in the transmission permission time zone determination procedure, the OLT 92 transmits information related to the transmission permission time zone to the AP 95. In the transmission procedure, the AP 95 controls transmission of downlink traffic based on information related to the transmission permission time zone. The optical wireless communication network in this embodiment is as shown in FIG.

  FIG. 14 shows a series of sequences relating to the traffic transmission control method in the present embodiment. In the management table creation procedure according to the present embodiment, first, the wireless frame generation / conversion unit 52 of AP95 # 1 issues a command relating to the wireless communication status inquiry of the wireless LAN terminal 91 # 1 connected to AP95 # 1 to the wireless LAN. Transmit to terminal 91 # 1 (S101). Next, the wireless frame generation / conversion unit 52 of AP95 # 1 receives wireless communication status response information from the wireless LAN terminal 91 # 1 (S102). Next, the table creation unit 55 of AP95 # 1 creates a table based on the wireless communication status response information received from the wireless LAN terminal 91 # 1. The radio frame generation / conversion unit 52 of AP95 # 1 transmits the table created by the table creation unit 55 to the OLT 92 (S103). The management table adding unit 25 of the OLT 92 creates a management table based on the table received from the AP 95.

In the transmission permission time zone determination procedure according to the present embodiment, the control signal generation unit 26 of the OLT 92 permits transmission based on the management table created from the table transmitted from the AP 95 # 1 and the observation information of the downlink traffic in the OLT 92. Determine the time zone.
In the transmission procedure according to the present embodiment, the PON signal processing unit 22 of the OLT 92 transmits the transmission permission time zone and downlink traffic determined by the transmission permission time zone determination procedure for each AP 95. Here, the PON signal processing unit 22 of the OLT 92 may transmit downlink traffic to all APs 95, and each AP 95 may extract only downlink traffic destined for the own AP 95.

  The PON signal processing unit 22 of the OLT 92 transmits to the AP 95 # 1 a control signal including information related to a transmission permission time zone indicating the transmission timing of the downlink traffic along with the downlink traffic (S104). After receiving the control signal, the radio frame generation / conversion unit 52 of AP95 # 1 transmits downlink traffic to the wireless LAN terminal 91 # 1 based on the control information (S105). In this embodiment, a management table creation procedure for creating a management table from a table in which information related to wireless communication status transmitted by the AP 95 to the OLT 92 is collected, and a transmission permission time zone determination procedure for determining a traffic transmission permission time zone in the OLT 92 are as follows. The same as in the first embodiment.

  A series of operations of the OLT 92 and transmission timing of downlink traffic from the OLT 92 to the wireless LAN terminals 91 # 1 to # 3 of the AP95 # 1 to AP95 # 3 will be described with reference to FIG. First, when the PON signal processing unit 22 of the OLT 92 receives a table from the AP 95, the management table adding unit 25 creates a management table, and the observation unit 28 sets the AP 95 # in the queue management unit 23 of the OLT 92 between t0 and t1. Observe the amount of downlink traffic transmitted to 1 to # 3. Next, the calculation unit 27 transmits the AP 95 # 1 to # 3 to the wireless LAN terminals 91 # 1 to # 3 based on the information regarding the downlink traffic amount and the wireless transmission rate in the management table between t1 and t2. The estimated transmission time is determined, and the transmission permission time zone is calculated. Next, during t2 to t3, the PON signal processing unit 22 transmits information regarding the transmission permission time zone from the OLT 92 to the AP 95 # 1 to # 3 as a control signal together with downlink traffic. Based on the information related to the transmission permitted time zone, the radio frame generation / conversion unit 52 of the AP95 # 1 to # 3 performs the wireless LAN terminal 91 # 1 to t3, t4 to t5, and t5 to t6, respectively. Downlink traffic is transmitted to # 3.

  In the present embodiment, the OLT 92 is described as an example of the communication device connected to the upper side of the AP 95, but the communication device may be the ONU 93. Further, in this embodiment, the traffic amount flowing into the queue management unit 23 in the OLT 92 at a certain time T is observed using the observation unit 28 and the timer 29, but the average value of the traffic amount flowing at the certain time T is measured. Or the average rate may be observed. In this embodiment, the transmission order from the OLT 92 is the order of AP95 # 1 to # 3, but the transmission order is not limited to this.

  In the present embodiment, the OLT 92 determines a transmission permitted time zone for downlink traffic based on the information on the radio status notified from the AP 95, the OLT 92 calculates the transmission permitted time zone and notifies the AP 95 of the downlink transmission permission time zone. By performing traffic transmission control, the wireless communication quality in the wireless LAN system can be improved. In the present embodiment, the control information is sent from the OLT 92 to the AP 95 so that transmission can be performed within the OLT 92 without calculating overhead such as transmission delay and processing delay in each communication terminal. Can be reduced.

(Embodiment 3)
The traffic control method according to the present embodiment includes a transmission permission time zone determination procedure and a transmission procedure in order. In the transmission permission time zone determination procedure, the OLT 92 takes into account the coverage area of each AP 95 and transmits the transmission permission time zone. To decide. As shown in FIG. 16, in the case where AP95 # 1 to # 3 are connected under the same OLT 92 as an optical wireless communication network, and one or more wireless LAN terminals 91 are connected to each of AP95. The operation will be described. The numbers of the APs 95 are # 1 to # 3, and the numbers of the wireless LAN terminals 91 are # 1 to # 5. As shown in FIG. 16, the cover areas A1 to A3 of the wireless LAN networks of AP95 # 1 to # 3 overlap.

A series of sequences relating to the traffic control method in the present embodiment is the same as that in the first embodiment. In the management table creation procedure, first, the wireless frame generation / conversion unit 52 of AP95 # 1 transmits a command related to the wireless communication status inquiry of the wireless LAN terminal 91 # 1 connected to the AP95 # 1 to the wireless LAN terminal 91 # 1. (S101). Next, the wireless LAN terminal 91 # 1 transmits information related to the wireless communication status answer to the AP 95 # 1 (S102). Next, the table creation unit 55 of the AP 95 # 1 creates a table based on the information obtained from the wireless LAN terminal 91 # 1, and the wireless frame generation / conversion unit 52 creates the table created by the table creation unit 55. Transmit to the OLT 92 (S103). The control signal generation unit 26 of the OLT 92 determines the transmission permission time zone based on the management table created based on the table transmitted from the AP95 # 1 and the observation information of the downlink traffic in the OLT 92. The PON signal processing unit 22 of the OLT 92 transmits downlink traffic to the AP 95 # 1 in accordance with the transmission permission time zone for the AP 95 # 1, and the radio frame generation / conversion unit 52 of the AP 95 # 1 includes the wireless LAN terminal 91 # 1. The received downlink traffic is transmitted to (S105). Here, AP95 # 1 has been described as an example. For example, in the case of AP95 # 2, the wireless LAN terminal 91 connected to AP95 # 2 corresponds to # 2 and # 4. In the case of AP95 # 3, the wireless LAN terminals 91 connected to AP95 # 3 are # 3 and # 5.

  In the traffic control method according to the present embodiment, in the management table creation procedure, each wireless LAN terminal 91 collects not only information on the connected AP 95 but also information on other APs 95 that are receiving radio waves. Create FIG. 17 shows a table created by each of the table creation units 55 of AP95 # 1 to # 3 in the present embodiment. In FIG. 17, the wireless LAN terminal 91 connected to the AP 95 # 1 is only # 1, and there is no other AP 95 from which the wireless LAN terminal 91 # 1 is receiving radio waves. The wireless LAN terminals 91 connected to the AP95 # 2 are # 2 and # 4, and the wireless LAN terminal 91 # 2 also receives radio waves from the AP95 # 1. The wireless LAN terminals 91 connected to the AP95 # 3 are # 3 and # 5, and the wireless LAN terminal 91 # 3 also receives radio waves from the AP95 # 1 and # 2. The radio frame generation / conversion unit 52 of each AP 95 transmits the management table to the OLT 92 after the table creation unit 55 creates the management table.

  FIG. 18 shows the management table of AP95 # 1 to # 3 updated by OLT 92. The management table in FIG. 18 is updated by adding the traffic amount and estimated transmission time of each AP 95 to the table in FIG. The OLT 92 determines the transmission permission time zone with reference to the estimated transmission time in the information regarding the updated management table in the APs # 1 to # 3 in FIG.

  A series of operations of the OLT 92 and traffic transmission timing from the OLT 92 to the APs 95 # 1 to # 3 will be described with reference to FIG. First, the PON signal processing unit 22 of the OLT 92 receives a table from the AP 95. Next, the observation unit 28 of the OLT 92 uses the timer 29 to observe the amount of traffic transmitted to the APs 95 # 1 to # 3 in the queue management unit 23 of the OLT 92 between t0 and t1.

  Next, the control signal generation unit 26 of the OLT 92 estimates the transmission time from the AP 95 # 1 to # 3 to the wireless LAN terminals 91 # 1 to # 5 based on the information regarding the traffic volume and the wireless transmission rate in the management table. To decide. Here, the control signal generation unit 26 of the OLT 92 determines the transmission permission time zone in consideration of, for example, an overbed such as a transmission delay or a processing delay in various communication terminals.

  Next, the PON signal processing unit 22 of the OLT 92 transmits to the wireless LAN terminals 91 # 1 and # 4 between AP95 # 1 and AP95 # 2 between t2 and t3 based on the information related to the determined transmission permission time zone. Send downstream traffic. Next, the wireless frame generation / conversion unit 52 of AP95 # 1 transmits downlink traffic to the wireless LAN terminal 91 # 1 between t3 and t6. In addition, the radio frame generation / conversion unit 52 of AP95 # 2 transmits downlink traffic to the wireless LAN terminal 91 # 4 between t3 and t4.

  Next, the radio frame generation / conversion unit 52 of the OLT 92 can transmit the downlink traffic during the transmission permission time period of the AP95 # 2 and the AP95 # 3, so that the AP95 # 2 and the AP95 between t5 and t6. Downlink traffic for wireless LAN terminals 91 # 2 and # 5 is transmitted to # 3. The wireless frame generation / conversion unit 52 of AP95 # 2 transmits wireless traffic between t6 and t9 so that downlink traffic can be transmitted during the transmission permission time zone of AP95 # 2 and AP95 # 3. Send down traffic to Further, the radio frame generation / conversion unit 52 of AP95 # 3 transmits downlink traffic to the wireless LAN terminal 91 # 5 between t6 and t8. Then, the PON signal processing unit 22 of the OLT 92 transmits downlink traffic to the wireless LAN terminal 91 # 3 to the AP 95 # 3 between t7 and t9. The radio frame generation / conversion unit 52 of AP95 # 3 transmits downlink traffic to the wireless LAN terminal 91 # 3 between t9 and t10.

  In the present embodiment, the OLT 92 has been described as an example of the communication device connected to the upper side of the AP 95, but the ONU 93 may be used. In addition, after the transmission permission time zone to each AP 95 is determined by the OLT 92, the OLT 92 does not control the transmission timing of the downstream traffic to the AP 95, but notifies the control information regarding the transmission permission time zone from the OLT 92 to the AP 95 as a control signal. You may do it. In addition, although the amount of traffic flowing into the queue management unit 23 in the OLT 92 at the fixed time T is observed by the timer 29, the average value or average rate of the amount of traffic flowing at the fixed time T may be observed. Further, although the transmission order from the OLT 92 is set to AP95 # 1 and AP95 # 2, AP95 # 2, AP95 # 3, and AP95 # 3, the transmission order is not limited to this. In the present embodiment, the OLT 92 performs efficient ordering with respect to the transmission permission time zone to each AP 95 based on the information of the wireless LAN terminal 91 subordinate to the coverage area of each AP 95, so compared with the first and second embodiments. Thus, the band utilization efficiency in each of the cover areas A1 to A3 can be improved.

  The optical wireless communication system and the traffic control method in the optical wireless communication system of the present invention can be applied to the communication industry.

21: PON-IF
22: PON signal processing unit 23: queue management unit 24: SNI
25: Management table addition unit 26: Control signal generation unit 27: Calculation unit 28: Observation unit 29: Timer 51: Antenna 52: Radio frame generation / conversion unit 53: Queue management unit 54: PHY port 55: Table creation unit 91: Wireless LAN terminal 92: OLT
93: ONU
95: AP
96: Splitters A1, A2, A3: AP95 cover area

Claims (8)

An optical wireless communication system in which a plurality of wireless base stations that perform wireless communication with a wireless terminal using the same frequency channel are connected to a communication device on the upper side of the wireless base station,
The communication device
A management table in which information related to wireless communication between the wireless base station and the wireless terminal is described;
Using the information related to wireless communication described in the management table and the observation result of the downlink traffic to the wireless terminal flowing into the communication device, so that the downlink traffic from the wireless base station to the wireless terminal does not collide. A communication apparatus side transmission control unit that determines a transmission permission time zone indicating transmission timing at which the radio base station transmits the downlink traffic to the radio terminal, and transmits the downlink traffic to the radio base station according to the transmission permission time zone When,
With
The radio base station is
A radio base station side transmission control unit for transmitting the downlink traffic received from the communication device to the radio terminal;
Prepared ,
You wherein the information relating to the wireless communication described in the management table is information relating to the wireless transmission rate for each of the radio terminal between said radio terminal and the radio base station,
Optical wireless communication system. An optical wireless communication system in which a plurality of wireless base stations that perform wireless communication with a wireless terminal using the same frequency channel are connected to a communication device on the upper side of the wireless base station,
The communication device
A management table in which information related to wireless communication between the wireless base station and the wireless terminal is described;
Using the information related to wireless communication described in the management table and the observation result of the downlink traffic to the wireless terminal flowing into the communication device, so that the downlink traffic from the wireless base station to the wireless terminal does not collide. A communication apparatus side transmission control unit that determines a transmission permission time zone indicating a transmission timing at which the radio base station transmits the downlink traffic to the radio terminal, and transmits the downlink traffic and the transmission permission time zone to the radio base station. When,
With
The radio base station is
A radio base station side transmission control unit that transmits the downlink traffic received from the communication device to the radio terminal according to the transmission permission time zone,
Prepared ,
You wherein the information relating to the wireless communication described in the management table is information relating to the wireless transmission rate for each of the radio terminal between said radio terminal and the radio base station,
Optical wireless communication system. The radio base station further includes a table creation unit that creates a table in which information related to radio communication between the radio base station and the radio terminal is described based on a request signal from the radio terminal,
The radio base station side transmission control unit transmits the table created by the table creation unit to the communication device,
The communication apparatus further includes a management table addition unit that adds the table received from the radio base station to the management table and updates the management table.
The optical wireless communication system according to claim 1 or 2.   The optical wireless communication system according to any one of claims 1 to 3, wherein information on other wireless base stations that can be received by the wireless terminal is also described in the management table as information related to wireless communication. A traffic control method in an optical wireless communication system in which a plurality of wireless base stations that perform wireless communication with a wireless terminal using the same frequency channel are connected to a communication device on the upper side of the wireless base station,
The communication device, using the observations of the downlink traffic to the wireless terminal entering the radio communication management table and the communication device information is described for the between said radio base station radio terminal, the radio A transmission permission time zone determination procedure for determining a transmission permission time zone indicating a transmission timing at which the radio base station transmits the downlink traffic to the radio terminal so that downlink traffic from the base station to the radio terminal does not collide ,
The communication device transmits the downlink traffic to the radio base station according to the transmission permission time zone, or the downlink traffic received by the radio base station from the communication device to the radio terminal according to the transmission permission time zone. Sending procedure to send,
Have a in order,
The information on the wireless communication described in the management table is information on a wireless transmission rate for each wireless terminal between the wireless base station and the wireless terminal ,
A traffic control method in an optical wireless communication system.   6. The traffic control method in the optical wireless communication system according to claim 5, wherein information on other wireless base stations that can be received by the wireless terminal is also described in the management table as information relating to wireless communication. A communication device connected to a plurality of radio base stations that perform radio communication with a radio terminal using the same frequency channel ,
A management table in which information related to wireless communication between the wireless base station and the wireless terminal notified from the wireless base station is described;
Using the information related to wireless communication described in the management table and the observation result of the downlink traffic to the wireless terminal flowing into the communication device, so that the downlink traffic from the wireless base station to the wireless terminal does not collide. A communication apparatus side transmission control unit that determines a transmission permission time zone indicating transmission timing at which the radio base station transmits the downlink traffic to the radio terminal, and transmits the downlink traffic to the radio base station according to the transmission permission time zone When,
With
The information on the wireless communication described in the management table is information on a wireless transmission rate for each wireless terminal between the wireless base station and the wireless terminal,
Communication device. A communication device connected to a plurality of radio base stations that perform radio communication with a radio terminal using the same frequency channel ,
A management table in which information related to wireless communication between the wireless base station and the wireless terminal notified from the wireless base station is described;
Using the information related to wireless communication described in the management table and the observation result of the downlink traffic to the wireless terminal flowing into the communication device, so that the downlink traffic from the wireless base station to the wireless terminal does not collide. A communication apparatus side transmission control unit that determines a transmission permission time zone indicating a transmission timing at which the radio base station transmits the downlink traffic to the radio terminal, and transmits the downlink traffic and the transmission permission time zone to the radio base station. When,
With
The information on the wireless communication described in the management table is information on a wireless transmission rate for each wireless terminal between the wireless base station and the wireless terminal,
Communication device.

Images