JP6241781B2 - COMMUNICATION DEVICE, COMMUNICATION SYSTEM, AND COMMUNICATION METHOD - Google Patents

Description

  The present invention relates to a communication device, a communication system, and a communication method.

  Conventionally, in a communication system including a plurality of communication devices, in order to grasp the state of the transmission path, estimation of a band that can be used in the transmission path (hereinafter also simply referred to as “band estimation”) has been performed. As a bandwidth estimation method, for example, a network bandwidth measurement method for measuring an available bandwidth of a transmission path is known (see, for example, Patent Document 1).

  In this network bandwidth measurement method, the transmission side device transmits a plurality of measurement packets whose packet sizes sequentially increase or decrease at a predetermined transmission interval, and the reception side device receives the transmitted measurement packets and receives the measurement packets. Measure the reception interval. In addition, the receiving side apparatus compares the transmission interval and the reception interval, and calculates the available bandwidth using the measurement packet having the largest packet size among the measurement packets having the same reception interval and transmission interval.

JP 2011-142622 A

  In the network bandwidth measurement method of Patent Document 1, the estimation accuracy of the bandwidth estimation of the transmission path is insufficient.

  The present invention has been made in view of the above circumstances, and provides a communication device, a communication system, and a communication method that can improve the estimation accuracy of the bandwidth estimation of the transmission path.

The communication apparatus according to the present invention is a communication apparatus that communicates with another communication apparatus via a transmission path, and a plurality of first packets having a transmission rate equal to or higher than a predetermined rate according to a band estimation method of the transmission path. Generating and generating a second packet having a transmission rate equal to or lower than the predetermined rate, and transmitting the second packet generated by the packet generator, and after transmitting the second packet, A packet communication unit configured to transmit a first packet; and a band setting unit configured to set a measurement band for estimating an available band of the transmission path . 1 packet and the second packet are transmitted .

The communication apparatus of the present invention is a communication apparatus that communicates with another communication apparatus via a transmission line, and a transmission rate generated by the other communication apparatus according to the band estimation method of the transmission line is equal to or higher than a predetermined rate. A packet communication unit that receives a plurality of first packets and receives a second packet whose transmission rate generated by the other communication device is equal to or lower than the predetermined rate; and the first packet by the packet communication unit A bandwidth estimation unit that estimates an available bandwidth of the transmission path based on reception results of the first packet and the second packet , wherein the bandwidth estimation unit receives the reception time and reception of the first packet. Based on the scheduled time and the reception time and scheduled reception time of the second packet, the available bandwidth of the transmission path is estimated .

The communication system of the present invention is a communication system in which a first communication device and a second communication device communicate with each other via a transmission line, and the first communication device depends on a band estimation method of the transmission line. A packet generation unit that generates a plurality of first packets having a transmission rate equal to or higher than a predetermined rate and generates a second packet whose transmission rate is equal to or lower than the predetermined rate; and the second generated by the packet generation unit A first packet communication unit that transmits the first packet after transmitting the second packet, and a band setting unit that sets a measurement band for estimating an available band of the transmission path, The first packet communication unit transmits the first packet and the second packet according to the measurement band, and the second communication device includes the plurality of first packets and the first packet. 2 A second packet communication unit that receives the packet, and an available bandwidth of the transmission path is estimated based on reception results of the first packet and the second packet received by the second packet communication unit A band estimation unit.

The communication method of the present invention is a communication method in a communication apparatus that communicates with another communication apparatus via a transmission line, and a plurality of first methods whose transmission rate is equal to or higher than a predetermined rate according to the band estimation method of the transmission line. Generating a second packet having a transmission rate equal to or lower than the predetermined rate, transmitting the generated second packet, and transmitting the second packet after transmitting the second packet. a transmission step of transmitting a packet, the possess a step of setting a measurement band of estimating the available bandwidth of the transmission path, said at transmitting step, in accordance with the measurement zone, said first packet and said second 2 packets are transmitted.

The communication method of the present invention is a communication method in a communication device that communicates with another communication device via a transmission line, and the transmission rate generated by the other communication device according to the bandwidth estimation method of the transmission line is Receiving a plurality of first packets equal to or higher than a predetermined rate, receiving a second packet having a transmission rate generated by the other communication device equal to or lower than the predetermined rate, and receiving the received first packet based the packet to the reception result between the second packet, have a, an estimation step of estimating the available bandwidth of the transmission path, the estimated step, reception time and the reception schedule of the first packet Based on the time and the reception time and scheduled reception time of the second packet, the available bandwidth of the transmission path is estimated.

  ADVANTAGE OF THE INVENTION According to this invention, the estimation precision of the band estimation of a transmission line can be improved.

Schematic diagram showing a configuration example of a communication system in the first embodiment The block diagram which shows the structural example of the communication terminal and communication server in 1st Embodiment. The schematic diagram which shows an example of the communication timing of the measurement packet sequence in 1st Embodiment The schematic diagram which shows an example of the threshold value holding table in 1st Embodiment The flowchart which shows the operation example of the communication terminal in the band estimation process in 1st Embodiment. The flowchart which shows the operation example of the communication server in the band estimation process in 1st Embodiment. The sequence diagram which shows the operation example of the communication system in the band estimation process in 1st Embodiment The block diagram which shows the structural example of the communication terminal and communication server in 2nd Embodiment. The schematic diagram which shows an example of the measurement zone | band holding | maintenance table in 2nd Embodiment. The flowchart which shows the operation example of the communication terminal in the band estimation process in 2nd Embodiment. The block diagram which shows the structural example of the communication terminal and communication server in 3rd Embodiment. Schematic diagram showing an example of a measurement bandwidth holding table for downlink in the third embodiment The schematic diagram which shows an example of the threshold value holding table in 3rd Embodiment 10 is a flowchart showing an operation example of a communication server in downlink bandwidth estimation processing in the third embodiment. 9 is a flowchart illustrating an operation example of a communication terminal in downlink band estimation processing in the third embodiment. FIG. 11 is a sequence diagram illustrating an operation example of a communication system when uplink bandwidth estimation processing and downlink bandwidth estimation processing are executed in a common sequence according to the third embodiment. Schematic diagram for explaining the conventional network bandwidth measurement method

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(Background to obtaining one embodiment of the present invention)
FIG. 17 is a schematic diagram for explaining the network bandwidth measuring method disclosed in Patent Document 1. In FIG. 17, the transmission side apparatus transmits a plurality of measurement packets whose packet sizes sequentially increase at a predetermined transmission interval, and the reception side apparatus receives the measurement packets. The receiving-side apparatus calculates the available bandwidth using the measurement packet having the maximum packet size among the measurement packets having the same reception interval and transmission interval.

  In FIG. 17, the transmission interval T10 and the reception interval T10 ′ between the measurement packet # 10 and the measurement packet # 11 are equal (T10 = T10 ′), and the transmission interval T11 and the reception interval T11 between the measurement packet # 11 and the measurement packet # 12. Is assumed to be equal (T11 = T11 ′). Further, the reception interval T12 ′ between the measurement packet # 12 and the measurement packet # 13 is larger than the transmission interval T12 (T12 ′> T12), and the reception interval T13 ′ between the measurement packet # 13 and the measurement packet # 14 is the transmission interval T13. Greater than (T13 ′> T13).

  In this case, the receiving side apparatus calculates the available bandwidth using the measurement packet # 11 having the largest packet size among the measurement packets # 10 and # 11 having the same reception interval and transmission interval.

  However, in the network bandwidth measurement system of Patent Document 1, for example, when fluctuation occurs in the transmission path, the arrival time of the measurement packet varies. In this case, the time at which the measurement packet arrives at the receiving side device is deviated from the scheduled arrival time.

  “Fluctuation” refers to a variation in arrival intervals for each packet in data communication, and is also referred to as jitter. The fluctuation is likely to occur when the communication path is congested. This variation is caused by, for example, a radio error or retransmission control associated with a radio error.

  The radio error includes, for example, signal degradation in the network medium, network link saturation, packet discard at an intermediate node due to measurement packet corruption, or network hardware malfunction. The retransmission control includes, for example, communicating the same data again when a confirmation response is not returned from the receiving side device within a predetermined time by TCP (Transmission Control Protocol).

  In the estimation method of Patent Document 1 shown in FIG. 17, there is a problem that the estimation accuracy deteriorates when the transmission path fluctuates. The period of the reception interval in the transmission line where the fluctuation occurs includes a difference in transmission time for each packet due to error control, retransmission control, or the like. Therefore, if the available bandwidth of the transmission path is estimated based on the reception interval affected by the difference in transmission time, the estimation accuracy of the transmission path bandwidth estimation may deteriorate.

Further, the network bandwidth measurement method disclosed in Patent Document 1 does not disclose that the packet response between the transmission side device and the reception side device differs depending on the transmission direction (for example, uplink / downlink) in the transmission path. For example, the packet response is different when the transmission path is vertically asymmetric. In this case, if the available bandwidth of the transmission path is estimated by a common method (algorithm) regardless of the transmission direction, there may be a case that the estimation suitable for one transmission direction is not a suitable estimation for the other transmission direction. . Therefore, the accuracy of transmission path band estimation may deteriorate.
In the case of the system shown in FIG. 1 to be described later, the communication terminal 100 can specify the wireless type, but the communication server 200 is often connected by wire via a base station or a relay station. When performing band estimation in the direction of the terminal 100), there is a problem that the wireless type cannot be considered.

  Hereinafter, embodiments of a communication device, a communication system, and a communication method that can improve the estimation accuracy of band estimation of a transmission path will be described. A plurality of embodiments described below can be used with each other within a consistent range.

(First embodiment)
FIG. 1 is a schematic diagram illustrating a configuration example of a communication system 1000 according to the first embodiment. The communication system 1000 includes a communication terminal 100, a communication server 200, and a transmission path 300. Communication terminal 100 and communication server 200 are connected via transmission line 300. The communication terminal 100 and the communication server 200 are examples of communication devices.

  The communication terminal 100 communicates with the communication server 200 via any one of a plurality of wireless types. The plurality of radio types include, for example, LTE (Long Term Evolution), HSPA (High Speed Packet Access), or WiFi (Wireless Fidelity).

  The communication terminal 100 and the communication server 200 execute a band estimation process. The band estimation process includes a series of processes for estimating the available band (transmission path band) of the transmission path 300.

  The communication terminal 100 selects at least one from a plurality of radio types and transmits a packet at a predetermined timing. Communication terminal 100 is connected to another communication device wirelessly.

  The communication server 200 receives the packet from the communication terminal 100, estimates the available bandwidth of the transmission path 300, and notifies the communication terminal 100 of the estimation result. In the bandwidth estimation process, the communication terminal 100 transmits, for example, a measurement packet sequence, and the communication server 200 observes the measurement packet sequence. The measurement packet sequence includes, for example, a bandwidth estimation packet and a fluctuation detection packet. The communication server 200 is connected to another communication device by wire or wireless.

  The bandwidth estimation packet includes, for example, an IP (Internet Protocol) packet, a UDP (User Datagram Protocol) packet, or an RTP (Real-time Transport Protocol) packet. Similarly, the fluctuation detection packet includes, for example, an IP packet, a UDP packet, or an RTP packet.

The transmission line 300 widely includes various networks (for example, a cellular phone network, a WAN (Wide Area Network), a LAN (Local Area Network), and a VPN (Virtual Private Network)). The transmission path 300 may include a transmission path for performing P2P (Peer to Peer) communication.
1 shows an example of a system in which the communication terminal 100 communicates with the communication server 200, the communication partner of the communication terminal 100 is not limited to the server, and may be terminals.

FIG. 2 is a block diagram illustrating a configuration example of the communication terminal 100 and the communication server 200.
The communication terminal 100 includes a reception unit 101, a wireless monitoring unit 102, a control unit 103, a storage unit 104, a packet generation unit 105, and a transmission unit 106.

  The receiving unit 101 receives, for example, various signals, various packets, or various data from other communication devices (for example, the communication server 200) via the transmission path 300.

  The wireless monitoring unit 102 monitors and determines the wireless type used for communication by the receiving unit 101 or the transmitting unit 106.

  The control unit 103 controls each unit in the communication terminal 100 in an integrated manner. Further, the control unit 103 sets a band (measurement band) to be subjected to band estimation processing, for example, according to the wireless type.

  The storage unit 104 stores various information, various data, and information on various tables, for example. The storage unit 104 holds, for example, a threshold holding table TB1 described later and information shared with the communication server 200 (for example, transmission pattern information).

  The packet generation unit 105 generates various packets according to instructions from the control unit 103.

  The transmission unit 106 transmits, for example, various signals, various packets, or various data to another communication device (for example, the communication server 200) via the transmission path 300.

  The wireless monitoring unit 102, the control unit 103, and the packet generation unit 105 include, for example, a CPU (Central Processing Unit) and a RAM (Random Access Memory). For example, the CPU implements each function by executing a predetermined program stored in the RAM. Further, the wireless monitoring unit 102, the control unit 103, and the packet generation unit 105 may be configured by dedicated hardware capable of executing a specific process.

  The communication server 200 includes a reception unit 201, a bandwidth estimation unit 202, a management unit 203, a storage unit 204, a packet generation unit 205, and a transmission unit 206.

  The receiving unit 201 receives, for example, various signals, various packets, or various data from another communication device (for example, the communication terminal 100) via the transmission path 300.

  The bandwidth estimation unit 202 estimates the available bandwidth of the transmission path 300 based on a packet (for example, a measurement packet sequence) received by the reception unit 201. The usable bandwidth of the transmission line 300 indicates, for example, the minimum transmission band (transmission rate) of each transmission line in the transmission line 300. If the transmission rate exceeds the available bandwidth, congestion may occur.

  The management unit 203 controls each unit in the communication server 200 in an integrated manner.

  The storage unit 204 stores, for example, various information, various data, and various table information. The storage unit 204 holds, for example, information shared with the communication terminal 100 (for example, transmission pattern information).

  The packet generation unit 205 generates various packets according to instructions from the management unit 203.

  The transmission unit 206 transmits, for example, various signals, various packets, or various data to another communication device (for example, the communication terminal 100) via the transmission path 300.

  Note that the bandwidth estimation unit 202, the management unit 203, and the packet generation unit 205 include, for example, a CPU (Central Processing Unit) and a RAM (Random Access Memory). For example, the CPU implements each function by executing a predetermined program stored in the RAM. Further, the bandwidth estimation unit 202, the management unit 203, and the packet generation unit 205 may be configured by dedicated hardware capable of executing a specific process.

  Next, band estimation processing by the communication system 1000 will be described.

  As a bandwidth estimation method for executing the bandwidth estimation processing, a plurality of bandwidth estimation methods can be considered. Below, some band estimation systems are illustrated. In the bandwidth estimation processing by each bandwidth estimation method, measurement packet sequences are transmitted and received sequentially. The measurement packet string includes a band estimation packet and a fluctuation detection packet. Here, the band estimation packet will be mainly described.

  In the first bandwidth estimation method, the communication terminal 100 sequentially changes the packet size of each bandwidth estimation packet, and transmits a packet with a constant transmission interval of each bandwidth estimation packet. That is, the communication terminal 100 transmits a packet so that the transmission rate (transmission band) of the band estimation packet increases. The communication server 200 searches for a point where the reception interval of the band estimation packet increases. The first band estimation method is also referred to as a PathQuick method.

  According to the first band estimation method, packets are transmitted from a low transmission rate, so the load on the transmission line 300 can be reduced. In addition, the estimation time required for the band estimation process can be shortened.

  In the second band estimation method, the communication terminal 100 sequentially changes the transmission interval of each band estimation packet, and transmits a packet while keeping the packet size of each band estimation packet constant. That is, the communication terminal 100 transmits a packet so that the transmission rate of the bandwidth estimation packet increases. The communication server 200 searches for a point where the reception interval of the band estimation packet increases. The second band estimation method is also referred to as a PathChirp method.

  According to the second bandwidth estimation method, since packets are transmitted from a low transmission rate, the load on the transmission line 300 can be reduced. In addition, the estimation time required for the band estimation process can be shortened.

  In the third bandwidth estimation method, the communication terminal 100 transmits a bandwidth estimation packet. The communication server 200 receives the bandwidth estimation packet and searches for a transmission rate at which the one-way delay tends not to increase. The third band estimation method is also referred to as a Pathload method.

  According to the third band estimation method, the estimation accuracy of the band estimation process can be improved.

  In the fourth band estimation method, the communication terminal 100 transmits a band estimation packet so that the transmission rate gradually decreases. The communication server 200 searches for a point where the reception interval of the band estimation packet becomes equal to the transmission interval. The fourth band estimation method is also referred to as an IGI (Initial Gap Incrementing) method.

  The fourth band estimation method is useful when the available band of the transmission line 300 is known to some extent and is stable.

  In the fifth bandwidth estimation method, the communication terminal 100 sequentially changes the packet size of the bandwidth estimation packet and transmits the packet. The communication server 200 derives a regression line between the packet size of the bandwidth estimation packet and the one-way delay, and estimates the available bandwidth of the transmission path 300 from the reciprocal of the slope of the regression line. The fifth band estimation method is also referred to as a one-packet method.

  According to the fifth band estimation method, the estimation time required for the band estimation process can be shortened.

  In the sixth bandwidth estimation method, the communication terminal 100 transmits two bandwidth estimation packets having the same packet size. The communication server 200 estimates the available bandwidth of the transmission path 300 according to the reception interval of two bandwidth estimation packets from the communication terminal 100. The sixth band estimation method is also referred to as a packet pair method.

  According to the sixth band estimation method, the time required for the band estimation process can be shortened.

  The communication terminal 100 and the communication server 200 select one of the band estimation methods and share the information of the band estimation method before executing the band estimation process. For example, one of the communication terminal 100 and the communication server 200 selects the band estimation method and notifies the other of the information of the band estimation method. Either one of the communication terminal 100 and the communication server 200 may notify the band estimation start signal for starting the band estimation process including the information of the band estimation method.

  By sharing the information of the band estimation method, the communication server 200 can grasp in advance the transmission pattern by the communication terminal 100 in the band estimation process.

  The transmission pattern includes, for example, a packet size of a packet included in a measurement packet sequence that is sequentially transmitted, a packet size changing method, a transmission interval, or a transmission interval changing method. For example, the communication terminal 100 and the communication server 200 store information on the band estimation method and the transmission pattern in the storage units 104 and 204.

  The bandwidth estimation process of the present embodiment does not ask the type of bandwidth estimation method, and any method may be used. The communication terminal 100 sequentially transmits a fluctuation detection packet and a band estimation packet to the communication server 200 according to any band estimation method. Each fluctuation detection packet is transmitted before each band estimation packet.

  For example, the transmission interval between the fluctuation detection packet and the bandwidth estimation packet is set by the control unit 103 within a predetermined interval that is estimated to be subjected to the same fluctuation in the transmission path 300. In this case, it is possible to remove the influence of fluctuation estimated to be the same as that of the previous fluctuation detection packet from the communication result of the band estimation packet.

  The fluctuation detection packet is a low-speed packet (for example, 128 kbps) having a predetermined rate or less, and is hardly affected by the available bandwidth of the transmission path 300 in communication from the communication terminal 100 to the communication server 200. Therefore, the reception time at which the communication server 200 receives the fluctuation detection packet varies according to the fluctuation in the transmission path 300. In the band estimation process, the packet sizes of the fluctuation detection packets may all be the same or different.

  FIG. 3 is a schematic diagram illustrating an example of communication timing of a measurement packet sequence.

  In FIG. 3, it is assumed that the first band estimation method is used as the band estimation method. In the first bandwidth estimation method, the communication terminal 100 sequentially increases the packet size of bandwidth estimation packets that are sequentially transmitted, and keeps the bandwidth estimation packet transmission interval constant. Accordingly, the transmission rate of the bandwidth estimation packet gradually increases.

  In FIG. 3, it is assumed that the transmission intervals of the fluctuation detection packet and the bandwidth estimation packet included in the same measurement packet sequence are substantially equal. That is, the intervals X0, X1, X2, and X3 are all equal. Further, it is assumed that the packet sizes of the fluctuation detection packets are almost the same. Therefore, the transmission rate of fluctuation detection packets is substantially constant.

  In the bandwidth estimation process, the header of the packet for fluctuation detection to be transmitted includes, for example, information on the transmission time by the communication terminal 100 and the packet number. For example, the communication server 200 derives the transmission time of the fluctuation detection packet by using the reception time and the transmission time when the fluctuation detection packet is received.

  Since the communication server 200 shares the transmission pattern in the band estimation process with the communication terminal 100 in advance, when the first fluctuation detection packet is received, the fluctuation detection packet and the band included in the second and subsequent measurement packet sequences The estimated reception time of the estimation packet can be derived.

  For example, in FIG. 3, the fluctuation detection packets are transmitted at the same transmission interval, so the communication server 200 detects the next (second) fluctuation detection after the interval T0 from the reception time of the first fluctuation detection packet. It is possible to derive that the packet is expected to arrive. Further, the communication server 200 can derive that the next (second) band estimation packet is expected to arrive after the interval X1 from the scheduled reception time of the second fluctuation detection packet, for example. Similarly, the communication server 200 can derive the scheduled reception time for other fluctuation detection packets and bandwidth estimation packets.

  Times j1, j2, and j3 in FIG. 3 are differences between the reception time of the fluctuation detection packet and the scheduled reception time derived for the fluctuation detection packet. Times j1, j2, and j3 are times including a communication delay due to fluctuations in the transmission path 300 during communication of the fluctuation detection packet.

  Times d1, d2, and d3 in FIG. 3 are differences between the reception time of the band detection packet and the scheduled reception time derived for the band estimation packet. Times d1, d2, and d3 are times including a communication delay due to the transmission path band and a communication delay due to fluctuation of the transmission path 300 during communication of the band estimation packet. The communication delay due to the transmission path band includes, for example, a delay that occurs when the transmission rate exceeds the available band of the transmission path 300 and cannot follow the transmission rate.

  Therefore, the communication server 200 derives from the time dn (n is an integer) a time excluding the communication delay time caused by the fluctuation of the transmission line 300, that is, the communication delay time caused by the transmission line band. For example, the communication server 200 derives the communication delay time by deriving a difference (dn−jn) between the time dn and the time jn (n is an integer).

  The communication server 200 compares the communication delay time resulting from the derived transmission path band with the band estimation threshold Th, and estimates the available band of the transmission path 300 according to the comparison result.

  For example, when the communication delay time resulting from the derived transmission path band is equal to or greater than the band estimation threshold Th, the communication server 200 is received one band before the band estimation packet in which this communication delay has occurred. The available bandwidth of the transmission line 300 is estimated using the bandwidth estimation packet. The transmission rate at which the band estimation packet received immediately before is transmitted is a packet that is equal to or less than the transmission path band and has the maximum transmission rate.

  The communication server 200 determines, for example, the packet size of the bandwidth estimation packet transmitted immediately before the transmission interval between the bandwidth estimation packet and the next fluctuation detection packet ((T0-X0), (T1). -X1), (T2-X2), or (T3-X3)). Thereby, the communication server 200 estimates the available bandwidth of the transmission path 300.

  The communication server 200 estimates the available bandwidth of the transmission path 300 using the bandwidth estimation packet transmitted a predetermined number of times before the bandwidth estimation packet transmitted immediately before. Also good. Even in this case, it is possible to ensure the band estimation accuracy equal to or higher than the predetermined standard.

  Even when a band estimation method other than the first band estimation method is used, the band estimation process can be executed similarly. For example, when the second bandwidth estimation method is used, the transmission interval of the measurement packet sequence is changed, but the fluctuation of the transmission line 300 can be detected even if the fluctuation detection packet is not transmitted at the same transmission interval.

Next, the band estimation threshold Th will be described.
FIG. 4 is a schematic diagram showing an example of a threshold value holding table TB1 that holds a band estimation threshold value Th.

  The band estimation threshold Th is set for each wireless type. For example, when the wireless type is LTE, the threshold A is set, when the wireless type is HSPA, the threshold B is set, and when the wireless type is WiFi, the threshold C is set. Each band estimation threshold Th is determined in advance and stored in the storage unit 204, for example. The band estimation unit 202 sets a band estimation threshold Th according to the wireless type when performing the band estimation process.

  For example, the band estimation threshold Th is compared with the time (dn−jn) during which the influence of fluctuation is eliminated. Therefore, for example, when the first band estimation method is used, the transmission interval T of the band estimation packet by the communication terminal 100 is constant, so that the band estimation threshold Th is equal to the transmission interval T (T0−X0, T1). -X1, T2-X2) may be set to approximate values.

  Further, when the difference between the transmission interval of the bandwidth estimation packet set by the communication terminal 100 and the transmission interval of the bandwidth estimation packet when actually transmitted from the terminal is equal to or greater than a predetermined value, the bandwidth estimation The unit 202 may be set with a predetermined threshold different from the set transmission interval. In addition, when the difference between the transmission timing based on the set transmission interval of the packet for estimating the band and the transmission timing determined by the radio resource allocated to the communication terminal 100 is equal to or greater than a predetermined value, the set transmission interval A predetermined threshold different from that may be set. In these cases, it is possible to improve the estimation accuracy of the band estimation even by using the band estimation threshold Th that is set uniquely.

  Next, an operation example of the communication system 1000 will be described.

  FIG. 5 is a flowchart showing an operation example of the communication terminal 100 in the band estimation process.

  First, the wireless monitoring unit 102 acquires wireless type information used for communication by the receiving unit 101 and the transmitting unit 106, and sends the information to the control unit 103 (S101).

  Subsequently, the control unit 103 acquires the parameter of the measurement packet sequence from the storage unit 104, for example, according to the acquired wireless type information, and sends the parameter to the packet generation unit 105 (S102). The parameter of the measurement packet sequence includes transmission pattern information. The transmission pattern information includes, for example, the packet size of each band estimation packet corresponding to the band estimation method and the packet size of each fluctuation detection packet. Also, the transmission pattern information includes, for example, information on the transmission interval of each band estimation packet, the transmission interval of each fluctuation detection packet, and the transmission interval between the band estimation packet and the fluctuation detection packet. .

  Further, the control unit 103 sets a measurement band according to the acquired wireless type information. The information on the measurement band is managed for each wireless type, and is stored in advance in the storage unit 104, for example. For example, when the wireless type is LTE, the measurement band is 0 to 50 (Mbps). When the wireless type is HSPA, the measurement band is 0 to 5.7 (Mbps). When the wireless type is WiFi, the measurement band is 0. ~ 600 (Mbps). Packets are generated and transmitted according to the measurement band.

  Subsequently, the packet generation unit 105 generates a fluctuation detection packet and a bandwidth estimation packet according to the parameters of the measurement packet sequence (S103). In this case, the packet generation unit 105 generates a packet size fluctuation detection packet and a bandwidth estimation packet according to the packet size information included in the parameter.

  Subsequently, the transmission unit 106 transmits the measurement packet sequence generated by the packet generation unit 105 (S104). In this case, the transmission unit 106 transmits a fluctuation detection packet and a band estimation packet at a predetermined timing. The predetermined timing is, for example, a timing in accordance with a transmission interval between each band estimation packet included in the parameter and a transmission interval between the band estimation packet and the fluctuation detection packet.

  According to the operation example of the communication terminal 100, since the fluctuation detection packet and the band estimation packet are sent in pairs, the communication server 200 on the receiving side has the transmission path 300 of which the influence of fluctuation of the transmission path 300 is removed. The available bandwidth can be estimated. Therefore, the estimation accuracy of band estimation can be improved.

  Further, since the measurement band is set according to the radio type, for example, the band estimation process can be executed with priority for the transmission path band that is frequently used in accordance with the characteristics of the radio type.

  FIG. 6 is a flowchart showing an operation example of the communication server 200 in the band estimation process.

  First, the bandwidth estimation unit 202 sets a bandwidth estimation threshold Th according to the wireless type used by the communication terminal 100 (S201). For example, the bandwidth estimation unit 202 derives a bandwidth estimation threshold Th with reference to the threshold holding table TB1 illustrated in FIG.

  Subsequently, the receiving unit 201 receives a packet via the transmission path 300 (S202).

  Subsequently, the bandwidth estimation unit 202 determines whether or not the received packet (reception packet) is a fluctuation detection packet (S203). Whether or not the packet is for fluctuation detection may be determined using identification information indicating that the packet is for fluctuation detection included in the header of the packet, for example. Further, when the packet size of the fluctuation detection packet is constant or regular, it may be determined from the packet size.

  When the received packet is a fluctuation detection packet, the bandwidth estimation unit 202 derives a time jn that is a difference between the reception time and the scheduled reception time of the fluctuation detection packet (S204). The scheduled reception time of the fluctuation detection packet may be derived by the management unit 203 from, for example, the reception time of the first fluctuation detection packet and the transmission pattern information. Alternatively, the reception unit 201 may acquire the scheduled reception time from the communication terminal 100.

  After the process of S204, the process returns to S202 to receive the next packet.

  If the received packet is not a fluctuation detection packet, that is, a bandwidth estimation packet, the bandwidth estimation unit 202 derives a time dn that is the difference between the reception time of the bandwidth estimation packet and the scheduled reception time. (S205). The estimated reception time of the bandwidth estimation packet may be derived by the management unit 203 from the reception time of the first fluctuation detection packet and the transmission pattern information, for example. Alternatively, the reception unit 201 may acquire the scheduled reception time from the communication terminal 100.

  After the times jn and dn are derived, the band estimation unit 202 determines that the difference (dn−jn) between the time jn related to the fluctuation detection packet and the time dn related to the band estimation packet is derived in S201. It is determined whether or not it is larger than the threshold value Th for use (S206).

  When (dn−jn) is equal to or less than the bandwidth estimation threshold Th, the process returns to S202 in order to receive the next packet.

  When (dn−jn) is larger than the bandwidth estimation threshold Th, the bandwidth estimation unit 202 estimates the available bandwidth of the transmission path 300 (S207).

  FIG. 6 illustrates the estimation of the available bandwidth of the transmission line 300 when (dn−jn) becomes equal to or greater than the bandwidth estimation threshold Th for the first time. The available bandwidth may be estimated when the number of times reached becomes a predetermined number or more. Thereby, even if the influence of fluctuation remains when the threshold value is first exceeded, the estimation accuracy of the available bandwidth can be improved.

  Subsequently, the packet generation unit 205 generates a packet including the estimation result of the usable bandwidth of the transmission path 300. The transmission unit 206 transmits the packet generated by the packet generation unit 205 to the communication terminal 100 via the transmission path 300 (S208).

  According to the operation example of the communication server 200, it is possible to estimate the available bandwidth of the transmission path 300 in consideration of the fluctuation effect of the transmission path 300 according to the reception results of the fluctuation detection packet and the bandwidth estimation packet. Therefore, the estimation accuracy of band estimation can be improved.

  For example, the transmission path 300 can be used in consideration of the fluctuation of the transmission path 300 using the reception time and scheduled reception time of the fluctuation detection packet and the reception time and scheduled reception time of the band estimation packet. Bandwidth can be estimated.

  In addition, since the bandwidth estimation process is executed using the times jn and dn, the usable bandwidth of the transmission line 300 can be estimated in consideration of the communication delay due to the transmission line band and the communication delay due to fluctuation. Therefore, the estimation accuracy of band estimation can be improved.

  Further, since the band estimation process is executed using the comparison result between the difference (dn−jn) between the times jn and dn and the band estimation threshold Th, the transmission path 300 can be used in which the influence of the fluctuation of the transmission path 300 is removed. Bandwidth can be estimated. Therefore, the estimation accuracy of band estimation can be improved.

  In addition, since the band estimation threshold Th is set according to the radio type, a threshold suitable for each radio type can be set, and the estimation accuracy of the band estimation can be improved.

  FIG. 7 is a sequence diagram illustrating an operation example of the communication system 1000 in the band estimation process.

  First, the communication terminal 100 detects a start trigger for band estimation processing (S301). The start trigger includes, for example, when the communication terminal 100 is turned on, when connected to the transmission line 300, when a handover (Hand Over) is predicted to be generated by the communication terminal 100, or when the reception level is decreased by the communication terminal 100.

  When detecting the start trigger, the communication terminal 100 transmits a band estimation start signal for starting band estimation in order to select an optimal communication transmission path (S302). The band estimation start signal may be, for example, a dedicated predetermined signal for notifying the start, or may be the first fluctuation detection packet shown in FIG. Further, the band estimation start signal may include, for example, transmission pattern information and radio type information.

  When receiving the band estimation start signal, the communication server 200 starts a band estimation process (S303), and transmits a response signal (band estimation start OK) to the band estimation start signal (S304).

  When receiving a response signal from the communication server 200, the communication terminal 100 executes, for example, the process of FIG. Specifically, for example, a packet train including a plurality of measurement packet sequences illustrated in FIG. 3 is transmitted to the communication server 200. That is, the communication terminal 100 sequentially transmits the first measurement packet sequence (S305), the second measurement packet sequence (S306), ..., the nth measurement packet sequence (S307). The number n of measurement packet sequences included in the packet train depends on, for example, a transmission pattern or a measurement band.

  When receiving each measurement packet sequence from the communication terminal 100, the communication server 200 estimates (for example, calculates) the available bandwidth of the transmission path 300 (S308). In this case, for example, the communication server 200 may estimate all the measurement packet sequences scheduled to be received after reception, may estimate one measurement packet sequence each time it is received, or a predetermined number of measurement packet sequences May be estimated for each reception.

  The communication server 200 transmits the estimation result of the usable bandwidth of the transmission path 300 to the communication terminal 100 (S309).

  When the bandwidth estimation process using one wireless type is completed, the communication terminal 100 and the communication server 200 switch to the next wireless type, for example, by the control unit 103 or the management unit 203 and start the bandwidth estimation process. That is, the bandwidth estimation process is executed for each wireless type.

  For example, the communication terminal 100 and the communication server 200 may sequentially switch all the radio types and execute the band estimation process to determine the best radio type. In addition, the communication terminal 100 and the communication server 200 may sequentially switch at least two radio types to estimate the band and determine the best radio type. In addition, the communication terminal 100 and the communication server 200 may determine a wireless type that satisfies a predetermined quality instead of the best wireless type.

  5 to 7 exemplify that the communication terminal 100 generates the parameter of the measurement packet sequence in consideration of the wireless type, and the communication server 200 estimates the bandwidth in consideration of the wireless type. You don't have to. When the radio type is not considered, the measurement band may not be limited.

  According to the communication system 1000, it is possible to estimate the usable bandwidth of the transmission line 300 in consideration of the influence of fluctuation of the transmission line 300, and it is possible to improve the estimation accuracy of the band estimation.

  Further, for example, when a communication with a large amount of data (for example, video transmission, communication in a TV conference system) is assumed, a high available bandwidth is required, but the wireless environment changes even if the communication terminal 100 moves slightly. There is. According to the communication system 1000, it is possible to easily and accurately determine which wireless type is highly efficient for wireless communication.

(Second Embodiment)
In the first embodiment, it is shown that the measurement band is limited or the measurement band is not limited according to the wireless type. In the second embodiment, a case where the measurement band is limited according to a predetermined condition other than the wireless type will be described.

  FIG. 8 is a block diagram illustrating a configuration example of the communication terminal 100B and the communication server 200 in the second embodiment. The communication system 1000B includes a communication terminal 100B and a communication server 200.

  Compared with the communication terminal 100 illustrated in FIG. 2, the communication terminal 100 </ b> B includes a wireless monitoring unit 102 </ b> B instead of the wireless monitoring unit 102, and includes a control unit 103 </ b> B instead of the control unit 103. In the communication system 1000B, the same components as those of the communication system 1000 illustrated in FIG. 2 are denoted by the same reference numerals, and description thereof is omitted or simplified.

  The wireless monitoring unit 102B monitors and determines the wireless type used for communication by the receiving unit 101 or the transmitting unit 106. The radio monitoring unit 102B monitors and discriminates (for example, measures) radio quality (for example, reception quality) by the receiving unit 101.

  The control unit 103B controls each unit in the communication terminal 100B in an integrated manner. Further, the control unit 103B sets the measurement band according to the predetermined information. The predetermined information will be described later. The control unit 103B is an example of a bandwidth setting unit.

Next, an example of setting the measurement band will be described.
Hereinafter, first to third setting examples are shown as measurement band setting examples.

  FIG. 9 is a schematic diagram illustrating an example of the measurement band holding table TB2 used in the first setting example to the third setting example. In the measurement band holding table TB2, the reception quality is exemplified for each radio type.

  In the first setting example, the control unit 103B sets the measurement band according to the reception quality determined by the wireless monitoring unit 102B.

  The reception quality of HSPA is, for example, RSCP (Received Signal Code Power). RSCP indicates the desired wave reception power, and indicates the reception power of the signal received by the reception unit 101.

  For example, when the RSCP measured by the wireless monitoring unit 102B is less than the predetermined threshold value α, the control unit 103B sets the measurement band to 128 kbps, 256 kbps, 384 kbps, 512 kbps, 768 kbps, and 1024 kbps. In this case, the communication terminal 100B sequentially transmits six measurement packet sequences (measurement packet sequences are fluctuation detection packets and bandwidth estimation packets).

  For example, when the RSCP measured by the radio monitoring unit 102B is equal to or greater than the predetermined threshold value α, the control unit 103B sets the measurement band to 128 kbps, 256 kbps, 384 kbps, 512 kbps, 768 kbps, 1024 kbps, and 2048 kbps.

  The reception quality of LTE is, for example, RSRP (Reference Signal Received Power) and RSRQ (Reference Signal Received Quality). RSRP indicates the reception power of the signal received by the reception unit 101. RSRQ indicates the reception quality of the signal received by the reception unit 101.

  For example, when the RSRP measured by the radio monitoring unit 102B is less than the predetermined threshold β1 or the RSRQ of the received packet is less than the predetermined threshold β2, the control unit 103B sets the measurement band to 128 kbps, 256 kbps, 384 kbps, 512 kbps, 768 kbps, Set to 1024 kbps.

  In addition, for example, when the RSRP measured by the radio monitoring unit 102B is equal to or larger than the predetermined threshold β1 and the RSRQ of the received packet is equal to or larger than the predetermined threshold β2, the control unit 103B sets the measurement bands to 512 kbps, 768 kbps, 1024 kbps, 1536 kbps, Set to 2048 kbps and 3072 kbps.

  The reception quality of WiFi is, for example, RSSI (Received Signal Strength Indication). RSSI indicates the strength of the signal received by the receiving unit 101.

  For example, when the RSSI measured by the radio monitoring unit 102B is less than the predetermined threshold γ, the control unit 103B sets the measurement band to 256 kbps, 384 kbps, 512 kbps, 768 kbps, 1024 kbps, and 2048 kbps.

  For example, when the RSSI measured by the radio monitoring unit 102B is equal to or greater than the predetermined threshold γ, the control unit 103B sets the measurement band to 256 kbps, 384 kbps, 512 kbps, 768 kbps, 2048 kbps, 3042 kbps.

  According to the first setting example, since a measurement band suitable for the reception quality can be set, the time required for the band estimation process can be shortened and necessary and sufficient estimation accuracy can be ensured. Therefore, the processing efficiency of the band estimation process can be improved. Further, when setting a measurement band suitable for the radio type and reception quality, the processing efficiency of the band estimation process can be further improved.

  Control unit 103B may set the measurement band according to radio quality other than the reception quality described above.

(Second setting example)
In the second setting example, it is assumed that the communication terminal 100B transmits video. When the data transmission band is changed in accordance with the quality of data (for example, video data, image data, audio data), the control unit 103B sets the measurement band according to the transmission band. In this case, the control unit 103B may set the measurement band in a stepwise manner when there are a plurality of data qualities in video transmission.

  For example, when the data quality changes to 400 (kbps) according to the application, the control unit 103B executes a band estimation process. In this case, for example, the control unit 103B sets the measurement band to the band of the transmission line 300 (for example, 384 (kbps) and 512 (kbps)) included in the predetermined band range including the changed data quality (400 (kbps)). Set. In this case, the relationship between the data quality and the transmission bandwidth is that the bandwidth used when sending 20 (fps) data is 256 to 384 (kbps), and the bandwidth used when sending 30 (fps) data is 384 to 512 (kbps). ), The data is transmitted at a quality of 20 (fps) if it passes up to 384 (kbps) and at a quality of 30 (fps) if it passes up to 512 (kbps), with 384 (kbps) and 512 (kbps) as the measurement band. It will be.

  In addition, for example, when the data quality further changes from 400 (kbps) to 600 (kbps), the control unit 103B may add a measurement band. For example, the control unit 103B adds the bandwidth (for example, 512 (kbps) and 768 (kbps)) of the transmission path 300 included in the predetermined bandwidth range including the changed data quality (600 (kbps)) to the measurement bandwidth. To do. As described above, the control unit 103B may set the measurement bands in stages and estimate the band in each measurement band.

  Further, when the change in data quality is within a predetermined range, the measurement band need not be changed. Thereby, the processing load of the communication server 200 can be reduced, and the estimation time required for the bandwidth estimation process can be shortened.

  According to the second setting example, the estimation time required for the band estimation process can be shortened, and necessary and sufficient estimation accuracy can be ensured. Therefore, the processing efficiency of the band estimation process can be improved. Further, the usable bandwidth of the transmission line 300 after the data quality change can be grasped in advance. Therefore, for example, when the state of the transmission path band corresponding to the transmission rate after changing the data quality is equal to or lower than the predetermined quality, the user can be notified in advance.

(Third setting example)
In the third setting example, the control unit 103B sets the end timing of the band estimation process. In this case, for example, the control unit 103B sets a predetermined target band in advance and stores it in the storage unit 204. The target band indicates, for example, the upper limit or lower limit of the measurement band.

  For example, when the bandwidth is estimated by sequentially switching from a low bandwidth to a high bandwidth in the transmission path 300, the control unit 103B estimates the bandwidth when the communication server 200 notifies that the target bandwidth is estimated to be an available bandwidth. The process ends. That is, when it is estimated that the target bandwidth is an available bandwidth, the control unit 103B ends the transmission of the measurement packet sequence even in the middle of the measurement bandwidth.

  For example, as shown in FIG. 9, when the wireless type is HSPA, the control unit 103B may set 768 (kbps) as the target band regardless of RSCP. In this case, when the communication server 200 estimates that 768 (kbps) is the usable bandwidth of the transmission line 300, the subsequent bandwidth estimation of the measurement bandwidth (for example, 1024 (kbps)) is omitted.

  Similarly, when the radio type is LTE, the control unit 103B sets 768 (kbps) as the target band when RSRP <β1 or RSRQ <β2, and sets 1536 kbps when RSRP ≧ β1 and RSRQ ≧ β2. It may be set as a target band. When the wireless type is WiFi, the control unit 103B may set 1024 kbps as the target band when RSSI <γ, and may set 2048 kbps as the target band when RSSI ≧ γ.

  According to the third setting example, the estimation time required for the band estimation process can be shortened. Therefore, the data quality in the communication system 1000B can be ensured.

  Next, an operation example of the communication system 1000B will be described.

  FIG. 10 is a flowchart illustrating an operation example of the communication terminal 100B in the band estimation process. FIG. 10 illustrates a case where the measurement band is set according to the first setting example. 10 is different from FIG. 5 in that radio quality is taken into consideration. In FIG. 10, points different from FIG. 5 are mainly described, and description of similar processing is omitted.

  First, the wireless monitoring unit 102 acquires wireless type information and wireless quality (for example, reception quality) information, and sends the information to the control unit 103B (S101B).

  Subsequently, the control unit 103B acquires the parameter of the measurement packet sequence from, for example, the storage unit 104 according to the acquired wireless type information and wireless quality information, and sends the parameter to the packet generation unit 105 (S102B).

  Further, the control unit 103B sets a measurement band according to the acquired wireless type information and wireless quality information (S102B). Packets are generated and transmitted according to the measurement band.

  According to the communication system 1000B, the estimation time required for the band estimation process can be shortened. Therefore, the data quality in the communication system 1000B can be ensured.

(Third embodiment)
In the first and second embodiments, the transmission direction of the transmission path 300 is not considered, but in the third embodiment, the band estimation process is executed in consideration of the transmission direction (for example, uplink and downlink). Show the case.

  FIG. 11 is a block diagram illustrating a configuration example of the communication terminal 100C and the communication server 200C in the third embodiment. The communication system 1000C includes a communication terminal 100C and a communication server 200C. Compared with communication terminal 100 shown in FIG. 2, communication terminal 100 </ b> C includes band estimation unit 107, and includes control unit 103 </ b> C instead of control unit 103. The communication server 200 </ b> C includes a management unit 203 </ b> C instead of the management unit 203 as compared with the communication server 200 illustrated in FIG. 2. In the communication system 1000C, the same components as those of the communication system 1000 shown in FIG. 2 are denoted by the same reference numerals, and description thereof is omitted or simplified.

  Also, in the transmission line 300, the transmission line from the communication terminal 100C to the communication server 200C is assumed to be an uplink 300A. In addition, in the transmission line 300, the transmission line from the communication server 200C to the communication terminal 100C is a downlink 300B.

  The wireless monitoring unit 102C monitors and determines the wireless type used for communication by the receiving unit 101 or the transmitting unit 106. Further, the wireless monitoring unit 102C may monitor and determine the wireless quality by the receiving unit 101.

  The control unit 103C controls each unit in the communication terminal 100C. Further, the control unit 103 derives the measurement band of the uplink 300A or the downlink 300B according to, for example, the radio type or radio quality.

  Band estimator 107 estimates the available bandwidth of downlink 300B based on the packet (for example, a measurement packet sequence) received by receiver 101.

  The management unit 203C controls each unit in the communication server 200 in an integrated manner. For example, when receiving information on the measurement band of the downlink 300B or information on the wireless quality from the communication terminal 100C, the management unit 203C sets the measurement band of the downlink 300B.

  Similar to communication terminal 100C, communication server 200C selects the wireless type used in communication terminal 100 and transmits a packet at a predetermined timing.

  Next, the measurement band of uplink 300A or downlink 300B will be described.

  Information on the measurement bands of the uplink 300A and the downlink 300B is managed for each wireless type, for example, and stored in advance in the storage units 104 and 204, for example.

  In the uplink 300A, for example, when the radio type is LTE, the measurement band is 0 to 50 (Mbps). When the radio type is HSPA, the measurement band is 0 to 5.7 (Mbps). The measurement band is 0 to 600 (Mbps).

  In the downlink 300B, for example, when the radio type is LTE, the measurement band is 0 to 100 (Mbps). When the radio type is HSPA, the measurement band is 0 to 14 (Mbps). The bandwidth is 0 to 600 (Mbps).

  Similarly to the second embodiment, the control unit 103C sets the measurement band of the uplink 300A according to the radio quality in the communication terminal 100C, or according to the radio type and the radio quality in the communication terminal 100C. Also good. In this case, the control unit 103C sets, for example, the measurement band of the uplink 300A with reference to the measurement band holding table TB2 illustrated in FIG.

  Further, control unit 103C or management unit 203C may set the measurement band of downlink 300B according to the radio quality in communication terminal 100C or according to the radio type and the radio quality in communication terminal 100C. In this case, the control unit 103C or the management unit 203C sets the measurement band of the downlink 300B with reference to, for example, the measurement band holding table TB3 illustrated in FIG. In the measurement band holding table TB3 of FIG. 12, the reception quality is exemplified for each radio type.

  When the measurement band holding tables TB2 and TB3 are compared, the measurement band (see the circle) in the measurement band holding table TB3 and the target band (see the double circle) are measured in the measurement band holding table TB3 for each wireless type. It can be understood that the bandwidth is higher than the target bandwidth. This is based on the fact that the bandwidths of uplink 300A and downlink 300B are asymmetric, and downlink 300B is often faster.

  The measurement band holding table TB3 is stored in, for example, the storage unit 104 of the communication terminal 100C or the storage unit 204 of the communication server 200C. When the communication terminal 100C holds the measurement band holding table TB3, for example, the control unit 103C refers to the measurement band holding table TB3 and determines the measurement band of the downlink 300B according to the reception quality determined by the radio monitoring unit 102C. Is derived. The transmitting unit 106 transmits a packet including the derived measurement band information to the communication server 200C. When communication server 200C receives information on the measurement band from communication terminal 100C, management unit 203C sets the measurement band for downlink 300B.

  On the other hand, when the communication server 200C holds the measurement band holding table TB3, for example, the transmission unit 106 transmits the reception quality information determined by the wireless monitoring unit 102C to the communication server 200C. When communication server 200C receives the reception quality information from communication terminal 100C, management section 203C refers to measurement band holding table TB3 and sets the measurement band of downlink 300B according to the reception quality information.

Next, the band estimation threshold Th will be described.
FIG. 13 is a schematic diagram illustrating an example of a threshold value holding table TB4 that holds a bandwidth estimation threshold value Th for the uplink 300A or the downlink 300B.

  The band estimation threshold Th is set for each wireless type. In the uplink 300A, for example, the threshold A is set when the radio type is LTE, the threshold B is set when the radio type is HSPA, and the threshold C is set when the radio type is WiFi. In the downlink 300B, for example, when the radio type is LTE, the threshold A ′ is set, when the radio type is HSPA, the threshold B ′ is set, and when the radio type is WiFi, the threshold C ′ is set. Is done. Each band estimation threshold Th is determined in advance and stored in the storage units 104 and 204, for example. The band estimation units 107 and 202 set the band estimation threshold Th according to the wireless type, for example, before performing the band estimation process.

  Next, an operation example of the communication system 1000C will be described.

  In the communication system 1000C, either the communication terminal 100C or the communication server 200C transmits a measurement packet sequence depending on whether the target of the bandwidth estimation process is the uplink 300A or the downlink 300B. The other of the communication terminal 100C and the communication server 200C receives the measurement packet sequence and estimates the available bandwidth of the uplink 300A or the downlink 300B.

  Note that the measurement packet sequence transmitted by the communication server 200C is the same as the measurement packet sequence transmitted by the communication terminals 100 and 100C, and thus detailed description thereof is omitted. The method for estimating the usable bandwidth of the downlink 300B by the communication terminal 100C is the same as the method of estimating the usable bandwidth of the uplink 300A by the communication server 200C. Since it is the same, detailed explanation is omitted.

  Next, an operation example of the communication system 1000C in the bandwidth estimation process of the uplink 300A will be described.

  Since the operation and effect of the communication system 1000C in the bandwidth estimation processing of the uplink 300A are the same as the operation and effect of the communication systems 1000 and 1000B in the first embodiment or the second embodiment, description thereof will be omitted. . For example, the operation of the communication system 1000C in the bandwidth estimation process of the uplink 300A is the same as the operation of the communication system 1000 shown in FIGS.

  Next, an operation example of the communication system 1000C in the bandwidth estimation process of the downlink 300B will be described.

  FIG. 14 is a flowchart showing an operation example of the communication server 200C in the bandwidth estimation process of the downlink 300B.

  First, management section 203C determines whether or not there is a request for bandwidth estimation processing for downlink 300B (S401). For example, communication terminal 100C may transmit a request for bandwidth estimation processing of downlink 300B to communication server 200C at a predetermined timing. This predetermined timing includes, for example, when the communication terminal 100C is turned on, when connected to the transmission line 300, when a handover (Hand Over) is predicted to occur by the communication terminal 100C, or when the reception level is lowered by the communication terminal 100C. .

  Further, the bandwidth estimation processing request for the downlink 300B may be periodically generated in the communication server 200C. In this case, for example, the elapse of a predetermined period is detected by a timer (not shown) of the management unit 203C. Thereby, the available bandwidth of the downlink 300B can be grasped periodically.

  When there is a request for bandwidth estimation processing of the downlink 300B, the reception unit 201 acquires information on the wireless type from the communication terminal 100C (S402). Accordingly, the communication server 200C can recognize the wireless type used by the communication terminal 100C.

  Further, when there is a request for bandwidth estimation processing of the downlink 300B, the reception unit 201 may also acquire information on the wireless quality from the communication terminal 100C, as with the communication terminal 100B in the second embodiment. Accordingly, the communication server 200C can recognize the wireless type used by the communication terminal 100C and the wireless quality in the communication terminal 100C.

  Subsequently, the management unit 203C acquires the parameters of the measurement packet sequence from the storage unit 204, for example, according to the acquired information on the wireless type or according to the information on the wireless type and the wireless quality (S403). Also, the management unit 203C sets the measurement band according to the acquired information on the wireless type or according to the information on the wireless type and the wireless quality. Packets are generated and transmitted according to the measurement band.

  Subsequently, the packet generation unit 205 generates a fluctuation detection packet and a bandwidth estimation packet according to the parameters of the measurement packet sequence (S404). In this case, the packet generation unit 205 generates a packet size fluctuation detection packet and a bandwidth estimation packet according to the packet size information included in the parameter.

  Subsequently, the transmission unit 206 transmits the measurement packet sequence generated by the packet generation unit 205 (S405). In this case, the transmission unit 206 transmits a fluctuation detection packet and a band estimation packet at a predetermined timing. The predetermined timing is, for example, a timing in accordance with a transmission interval between each band estimation packet included in the parameter and a transmission interval between the band estimation packet and the fluctuation detection packet.

  According to the operation example of the communication server 200C, the fluctuation detection packet and the bandwidth estimation packet are sent in pairs, so that the communication terminal 100C on the receiving side can receive the downlink 300B from which the influence of the fluctuation of the downlink 300B has been removed. The available bandwidth can be estimated. Therefore, it is possible to improve the estimation accuracy of the bandwidth estimation of the downlink 300B.

  In addition, since the measurement band of the downlink 300B is set according to the radio type, for example, the band estimation process can be executed with priority for the band of the downlink 300B that is frequently used according to the characteristics of the radio type.

  Also, when setting the measurement band of the downlink 300B according to the radio quality, the estimation time required for the band estimation process of the downlink 300B can be shortened, and necessary and sufficient estimation accuracy can be ensured. Therefore, it is possible to ensure downlink data quality in the communication system 1000C.

  FIG. 15 is a flowchart showing an operation example of the communication terminal 100C in the bandwidth estimation processing of the downlink 300B.

  First, the bandwidth estimation unit 107 derives a bandwidth estimation threshold Th according to the wireless type used by the communication terminal 100C (S501). For example, the bandwidth estimation unit 107 derives a bandwidth estimation threshold Th with reference to the threshold holding table TB4 illustrated in FIG.

  Subsequently, the receiving unit 101 receives a packet via the downlink 300B (S502).

  Subsequently, the receiving unit 101 determines whether or not the received packet is a fluctuation detection packet (S503). Whether or not the packet is for fluctuation detection may be determined using identification information indicating that the packet is for fluctuation detection included in the header of the packet, for example. Further, when the packet size of the fluctuation detection packet is constant or regular, it may be determined from the packet size.

  When the received packet is a fluctuation detection packet, the bandwidth estimation unit 107 derives a time jn that is a difference between the reception time and the scheduled reception time of the fluctuation detection packet (S504). For example, the scheduled reception time of the fluctuation detection packet may be derived by the control unit 103C from the reception time of the first fluctuation detection packet and the transmission pattern information. In addition, the reception unit 101 may acquire the scheduled reception time from the communication server 200C.

  After the process of S504, the process returns to S502 to receive the next packet.

  If the received packet is not a fluctuation detection packet, that is, a band estimation packet, the band estimation unit 107 derives a time dn that is the difference between the reception time of the band estimation packet and the scheduled reception time. (S505). The scheduled reception time of the bandwidth estimation packet may be derived by the control unit 103C from the reception time of the first fluctuation detection packet and the transmission pattern information, for example. In addition, the reception unit 101 may acquire the scheduled reception time from the communication server 200C.

  After the times jn and dn are derived, the bandwidth estimation unit 107 determines that the difference (dn−jn) between the time jn related to the fluctuation detection packet and the time dn related to the bandwidth estimation packet is based on the threshold derived in S501. It is determined whether it is larger (S307).

  If (dn−jn) is equal to or less than the bandwidth estimation threshold Th, the process returns to S502 to receive the next packet.

  When (dn−jn) is larger than the threshold, the bandwidth estimation unit 107 estimates the available bandwidth of the downlink 300B (S507).

  FIG. 15 illustrates the estimation of the available bandwidth of the downlink 300B when (dn−jn) becomes equal to or greater than the bandwidth estimation threshold Th for the first time. The available bandwidth may be estimated when the number of times reached becomes a predetermined number or more. Thereby, even if the influence of fluctuation remains when the threshold value is first exceeded, the estimation accuracy of the available bandwidth can be improved.

  According to the operation example of the communication terminal 100C, the influence of the fluctuation of the downlink 300B is determined using the reception time and scheduled reception time of the fluctuation detection packet and the reception time and scheduled reception time of the band estimation packet. The available bandwidth of the downlink 300B in consideration can be estimated. Therefore, the estimation accuracy of band estimation can be improved.

  In addition, since the bandwidth estimation process is executed using the times jn and dn, the available bandwidth of the downlink 300B can be estimated in consideration of the communication delay caused by the bandwidth of the downlink 300B and the communication delay caused by fluctuation. . Therefore, the estimation accuracy of band estimation can be improved.

  Further, since the band estimation process is executed using the comparison result between the difference (dn−jn) between the times jn and dn and the band estimation threshold value Th, the downlink 300B can be used without the influence of fluctuation of the downlink 300B. Bandwidth can be estimated. Therefore, the estimation accuracy of band estimation can be improved.

  Further, since the band estimation threshold Th is set according to the radio type used by the communication terminal 100C, a threshold suitable for each radio type can be set, and the estimation accuracy of the band estimation can be improved.

  In the present embodiment, the communication of the fluctuation detection packet in the bandwidth estimation process of the uplink 300A or the downlink 300B may be omitted. In this case, the available bandwidth of the uplink 300A or the downlink 300B is estimated by a known method that does not use a fluctuation detection packet. Based on the fact that the reception rate (reception bandwidth) of the band estimation packet is lower than the transmission rate when the transmission rate of the bandwidth estimation packet by the communication server 200C is equal to or greater than the usable bandwidth of the transmission path 300. The usable bandwidth of the transmission line 300 may be estimated.

  Next, the execution timing of the bandwidth estimation process for uplink 300A and the bandwidth estimation process for downlink 300B will be described.

  The communication system 1000C may execute only one of the bandwidth estimation processing of the uplink 300A and the bandwidth estimation processing of the downlink 300B, or both. When both are executed, the communication system 1000C may execute the bandwidth estimation processing of the uplink 300A and the bandwidth estimation processing of the downlink 300B individually or in a common sequence.

  When only one or both of the bandwidth estimation processes of the uplink 300A and the downlink 300B are performed, in the bandwidth estimation process of the uplink 300A, the communication system 1000C executes the process shown in FIG. To do. For example, the communication terminal 100C transmits a band estimation start signal and a measurement packet sequence, and the communication server 200C estimates an available band.

  On the other hand, when only one of the above is executed or when both are executed individually, in the bandwidth estimation process of downlink 300B, communication system 1000C executes the same process as the process shown in FIG. The subject (communication terminal 100C / communication server 200C) reverses. For example, the communication server 200C transmits a band estimation start signal and a measurement packet sequence, and the communication terminal 100C estimates an available band. Further, when both the bandwidth estimation processing for the uplink 300A and the downlink 300B are executed individually, the start triggers of the bandwidth estimation processing may be different.

  When both the bandwidth estimation process of uplink 300A and the bandwidth estimation process of downlink 300B are executed, communication system 1000C may execute both bandwidth estimation processes in a common sequence.

  FIG. 16 is a sequence diagram illustrating an operation example of the communication system 1000C when performing bandwidth estimation processing for the uplink 300A and the downlink 300B in a common sequence.

  First, the communication terminal 100C detects a start trigger for the band estimation process (S601). The start trigger includes, for example, when the communication terminal 100C is turned on, when connected to the transmission line 300, when a handover occurrence is predicted by the communication terminal 100C, or when the reception level is lowered by the communication terminal 100C.

  When the communication terminal 100C detects the start trigger, the communication terminal 100C transmits a band estimation start signal (S602).

  When the communication server 200C receives the band estimation start signal, the communication server 200C starts transmitting the measurement packet sequence for the downlink 300B (S603). Note that the communication server 200C does not consider the arrival of the measurement packet sequence for the uplink 300A after the transmission of the measurement packet sequence for the downlink 300B is started. That is, the bandwidth estimation process of the downlink 300B is executed without depending on the bandwidth estimation process of the uplink 300A.

  After receiving the first measurement packet sequence for the downlink 300B from the communication server 200C, the communication terminal 100C starts transmitting the measurement packet sequence for the uplink 300A (S604). Note that the communication terminal 100C does not consider the arrival of the measurement packet sequence for the downlink 300B after the transmission of the measurement packet sequence for the uplink 300A is started. That is, the bandwidth estimation process of the uplink 300A is executed without depending on the bandwidth estimation process of the downlink 300B.

  Each of the communication terminal 100C and the communication server 200C sequentially transmits a measurement packet sequence (S605, 606).

  When receiving each measurement packet sequence from the communication server 200C, the communication terminal 100C estimates the available bandwidth of the downlink 300B (S607). In this case, for example, the communication terminal 100C may estimate all the measurement packet sequences scheduled to be received after reception, may estimate one measurement packet sequence for each reception, or may be a predetermined number of measurement packet sequences May be estimated for each reception.

  In addition, when receiving each measurement packet sequence from the communication terminal 100C, the communication server 200C estimates the available bandwidth of the uplink 300A (S608). In this case, for example, the communication server 200C may estimate all measurement packet sequences scheduled to be received after reception, may estimate one measurement packet sequence each time it is received, or a predetermined number of measurement packet sequences May be estimated for each reception.

  The communication server 200C transmits the estimation result of the available bandwidth of the uplink 300A to the communication terminal 100C (S609). Thereby, the communication terminal 100C can grasp the available bandwidth of the uplink 300A.

  The communication terminal 100C may notify the estimation result of the available bandwidth of the downlink 300B to the communication server 200C according to, for example, an application executed by the control unit 103C (S610). In this case, the communication terminal 100C can grasp the available bandwidth of the downlink 300B. The notification of the estimated result of the available bandwidth of the downlink 300B can be omitted.

  According to the processing of FIG. 16, after starting one of the bandwidth estimation processing of the uplink 300A and the bandwidth estimation processing of the downlink 300B, a special trigger is not required and the other can be executed. Therefore, the available bandwidth of the uplink 300A and the downlink 300B can be easily grasped.

  According to the communication system 1000C, it is possible to improve the estimation accuracy of the band estimation for each transmission direction even when the packet response differs depending on the transmission direction (for example, the uplink 300A and the downlink 300B). Therefore, for example, the estimation accuracy of the transmission path can be improved even in a vertically asymmetric transmission path.

  Furthermore, when a fluctuation detection packet is transmitted together with a band detection packet, the usable band of the transmission path 300 can be estimated while suppressing the influence of fluctuation in the transmission direction of the packet on the transmission path.

  The present invention is not limited to the configuration of the above-described embodiment, and any configuration can be used as long as the functions shown in the claims or the functions of the configuration of the present embodiment can be achieved. Is also applicable.

  For example, in the above-described embodiment, other communication terminals may have the functions of the communication servers 200 and 200C. That is, you may perform a band estimation process between several communication terminals.

  In the third embodiment, when the best radio type estimated by the band estimation process is different between the uplink and the downlink, the communication system 1000C determines the radio type with the best band estimation result on the uplink. You may choose. Also, the best radio type may be selected with emphasis on the uplink band estimation result. For example, each of the uplink and downlink band estimation results may be weighted or prioritized, for example, to select the best radio type. Further, when it is assumed that the downlink is mainly used, the best radio type may be selected by placing importance on the downlink band estimation result.

  Moreover, you may combine each of 1st-3rd embodiment.

  The present invention is also applicable to a communication program that implements the functions of the above-described embodiments by supplying a communication program to a communication device via a network or various storage media, and reading and executing the computer in the communication device. .

(Outline of one embodiment of the present invention)
A communication apparatus according to an aspect of the present invention is a communication apparatus that communicates with another communication apparatus via a transmission line, and a plurality of first devices whose transmission rate is equal to or higher than a predetermined rate according to a band estimation method of the transmission line. A packet generation unit that generates a second packet having a transmission rate equal to or lower than the predetermined rate, and transmits the second packet generated by the packet generation unit. A packet communication unit that transmits the first packet after transmission.

  According to this configuration, since the first packet and the second packet are sent in pairs, the receiving-side communication apparatus can estimate the usable bandwidth of the transmission path by removing the influence of fluctuations in the transmission path. Therefore, it is possible to improve the estimation accuracy of the bandwidth estimation of the transmission path.

  The communication apparatus according to an aspect of the present invention includes a band setting unit that sets a measurement band for estimating an available band of the transmission path according to a radio type of the transmission path, and the packet communication unit includes the The first packet and the second packet are transmitted according to the measurement band.

  According to this configuration, for example, it is possible to preferentially estimate a band of a transmission path that is frequently used according to the characteristics of the wireless type.

  The communication apparatus according to an aspect of the present invention includes a communication quality acquisition unit that acquires communication quality information from the packet communication unit, and the transmission path according to the communication quality information acquired by the communication quality acquisition unit. A bandwidth setting unit configured to set a measurement bandwidth for estimating the available bandwidth, and the packet communication unit transmits the first packet and the second packet according to the measurement bandwidth.

  According to this configuration, since a measurement band suitable for communication quality can be set, the time required for band estimation can be shortened, and necessary and sufficient estimation accuracy can be ensured. Therefore, the processing efficiency of bandwidth estimation can be improved.

  The communication apparatus according to an aspect of the present invention includes a bandwidth setting unit that sets a measurement bandwidth for estimating an available bandwidth of the transmission path according to quality of data communicated by the packet communication unit, and the packet The communication unit transmits the first packet and the second packet according to the measurement band.

  According to this configuration, since a measurement band suitable for data quality can be set, the estimation time required for band estimation can be shortened, and necessary and sufficient estimation accuracy can be ensured. Therefore, the processing efficiency of bandwidth estimation can be improved.

  The communication apparatus according to an aspect of the present invention includes a band setting unit that sets an upper limit or a lower limit of a measurement band for estimating an available band of the transmission path, and the packet communication unit is configured according to the measurement band, The first packet and the second packet are transmitted.

  According to this configuration, since the end timing of band estimation can be set, the estimation time required for band estimation can be shortened and necessary and sufficient estimation accuracy can be ensured. Therefore, the processing efficiency of bandwidth estimation can be improved.

  The communication apparatus according to an aspect of the present invention includes a band setting unit that sets a measurement band for estimating an available band of the transmission path according to a transmission direction in the transmission path, and the packet communication unit includes the The first packet and the second packet are transmitted according to the measurement band.

  According to this configuration, since a measurement band suitable for the transmission direction can be set, the estimation time required for band estimation can be shortened, and necessary and sufficient estimation accuracy can be ensured. Therefore, the processing efficiency of bandwidth estimation can be improved.

  In the communication device according to an aspect of the present invention, the packet communication unit transmits the first packet within a predetermined time from the transmission of the second packet.

  According to this configuration, it is possible to estimate the available bandwidth of the transmission path that includes the same level of fluctuation as that during communication of the second packet. Therefore, the estimation accuracy of the band estimation can be improved by eliminating the influence of fluctuation using the second packet.

  Further, in the communication device according to an aspect of the present invention, the packet generation unit generates the first packet and the second packet according to a packet size according to a bandwidth estimation method adopted by the communication device, The packet communication unit transmits the first packet and the second packet according to the transmission interval according to the bandwidth estimation method adopted by the communication device.

  According to this configuration, it is possible to improve the estimation accuracy of the usable bandwidth of the transmission path using any one of the bandwidth estimation methods.

  In the communication device according to an aspect of the present invention, the packet generation unit generates the first packet by sequentially changing a transmission rate, and the packet communication unit includes the first packet and the second packet. Send packets sequentially.

  According to this configuration, for example, by transmitting packets from a low transmission rate, the load on the transmission path can be reduced. In addition, the estimation time required for band estimation can be shortened.

  In addition, the communication device according to an aspect of the present invention receives a plurality of first packets having a transmission rate generated by the other communication device according to the bandwidth estimation method of the transmission path that is equal to or higher than a predetermined rate, A packet communication unit that receives a second packet having a transmission rate generated by another communication device that is equal to or lower than the predetermined rate, and a reception result of the first packet and the second packet by the packet communication unit. And a bandwidth estimation unit that estimates an available bandwidth of the transmission path.

  According to this configuration, the usable bandwidth of the transmission path can be estimated in consideration of the influence of the fluctuation of the transmission path, according to the reception results of the first packet and the second packet. Therefore, the estimation accuracy of band estimation can be improved.

  Further, in the communication device according to an aspect of the present invention, the bandwidth estimation unit is based on the reception time and scheduled reception time of the first packet, and the reception time and scheduled reception time of the second packet, An available bandwidth of the transmission path is estimated.

  According to this configuration, the usable bandwidth of the transmission path can be estimated in consideration of the influence of the fluctuation of the transmission path, according to the scheduled reception time and the reception time of the first packet and the second packet. Therefore, the estimation accuracy of band estimation can be improved.

  In the communication device according to an aspect of the present invention, the bandwidth estimation unit may include a first time that is a difference between a reception time of the first packet and a scheduled reception time of the first packet; The available bandwidth of the transmission path is estimated based on the second time that is the difference between the reception time of the second packet and the scheduled reception time of the second packet.

  According to this configuration, the usable bandwidth of the transmission path can be estimated in consideration of the communication delay due to the usable bandwidth of the transmission path and the communication delay due to fluctuation. Therefore, the estimation accuracy of band estimation can be improved.

  In the communication apparatus according to an aspect of the present invention, the bandwidth estimation unit may be a predetermined number of times when a third time that is a difference between the first time and the second time is equal to or greater than a predetermined threshold. The available bandwidth of the transmission path is estimated based on the transmission rate of the first packet transmitted by the other communication device.

  According to this configuration, the usable bandwidth of the transmission path can be estimated from the transmission rate around the time when the communication delay due to the usable bandwidth of the transmission path that eliminates the communication delay due to fluctuation becomes a predetermined threshold, The estimation accuracy of band estimation can be improved.

  Further, in the communication device according to an aspect of the present invention, the bandwidth estimation unit includes information on transmission patterns of the first packet and the second packet by the other communication device, and the first packet communication unit. At least one of the scheduled reception time of the first packet and the scheduled reception time of the second packet is derived based on the reception time of the second packet.

  According to this configuration, by sharing the transmission pattern in advance, it is possible to derive the scheduled reception time of each packet according to the reception of the first second packet.

  Moreover, the communication apparatus according to an aspect of the present invention includes a threshold setting unit that sets the predetermined threshold according to the wireless type of the transmission path.

  According to this configuration, it is possible to set a threshold value for bandwidth estimation of a transmission path in consideration of transmission timing and communication delay that are expected to be different for each wireless type. Therefore, the estimation accuracy of band estimation can be improved.

  The communication apparatus according to an aspect of the present invention includes a threshold setting unit that sets the predetermined threshold according to a transmission direction in the transmission path.

  According to this configuration, it is possible to set a threshold for band estimation of a transmission path in consideration of transmission timing and communication delay that are expected to be different for each transmission direction (for example, uplink and downlink). Therefore, the estimation accuracy of band estimation can be improved.

  A communication system according to one aspect of the present invention is a communication system in which a first communication device and a second communication device communicate via a transmission line, and the first communication device has a bandwidth of the transmission line. Generated by the packet generator, a packet generator that generates a plurality of first packets with a transmission rate equal to or higher than a predetermined rate according to the estimation method, and generates a second packet with a transmission rate equal to or lower than the predetermined rate A first packet communication unit that transmits the second packet that has been transmitted and transmits the first packet after the transmission of the second packet, wherein the second communication device includes the plurality of first packets The second packet communication unit that receives the second packet and the second packet, and the transmission based on the reception result of the first packet and the second packet received by the second packet communication unit. Includes a bandwidth estimation section for estimating the available bandwidth, the.

  According to this configuration, since the first packet and the second packet are sent in pairs, the usable bandwidth of the transmission path can be estimated by removing the influence of the fluctuation of the transmission path. Therefore, it is possible to improve the estimation accuracy of the bandwidth estimation of the transmission path.

  A communication method according to an aspect of the present invention is a communication method in a communication device that communicates with another communication device via a transmission line, and a transmission rate is equal to or higher than a predetermined rate according to a band estimation method of the transmission line. Generating a plurality of first packets, generating a second packet having a transmission rate equal to or lower than the predetermined rate, transmitting the generated second packet, and transmitting the second packet Transmitting the first packet later.

  According to this method, since the first packet and the second packet are sent in pairs, the communication apparatus on the receiving side can estimate the usable bandwidth of the transmission path by removing the influence of fluctuation of the transmission path. Therefore, it is possible to improve the estimation accuracy of the bandwidth estimation of the transmission path.

  A communication method according to an aspect of the present invention is a communication method in a communication device that communicates with another communication device via a transmission line, and is generated by the other communication device according to a band estimation method of the transmission line. Receiving a plurality of first packets whose transmission rate is equal to or higher than a predetermined rate, and receiving a second packet whose transmission rate generated by the other communication device is equal to or lower than the predetermined rate; and Estimating the available bandwidth of the transmission path based on the received results of the first packet and the second packet.

  According to this method, the usable bandwidth of the transmission path can be estimated in consideration of the influence of the fluctuation of the transmission path according to the reception results of the first packet and the second packet. Therefore, the estimation accuracy of band estimation can be improved.

  INDUSTRIAL APPLICABILITY The present invention is useful for communication apparatuses, communication systems, communication methods, and the like that can improve the estimation accuracy of transmission path band estimation.

1000, 1000B, 1000C Communication system 100, 100B, 100C Communication terminal 101 Reception unit 102, 102B, 102C Radio monitoring unit 103, 103B, 103C Control unit 104 Storage unit 105 Packet generation unit 106 Transmission unit 107 Band estimation unit 200, 200C Communication Server 201 Reception unit 202 Band estimation unit 203, 203C Management unit 204 Storage unit 205 Packet generation unit 206 Transmission unit 300 Transmission path 300A Uplink 300B Downlink

Claims (18)

A communication device that communicates with other communication devices via a transmission path,
A packet generation unit that generates a plurality of first packets having a transmission rate equal to or higher than a predetermined rate according to a bandwidth estimation method of the transmission path, and generates a second packet whose transmission rate is equal to or lower than the predetermined rate;
A packet communication unit that transmits the second packet generated by the packet generation unit, and transmits the first packet after the transmission of the second packet;
A bandwidth setting unit for setting a measurement bandwidth for estimating the available bandwidth of the transmission path;
Equipped with a,
The packet communication unit is a communication device that transmits the first packet and the second packet according to the measurement band . The communication device according to claim 1,
The band setting unit, in response to said radio type of the transmission path, the measurement zone to set the communication apparatus. The communication device according to claim 1, further comprising:
A communication quality acquisition unit for acquiring communication quality information by the packet communication unit ;
The band setting unit, in response to said acquired communication quality information by the communication quality acquisition unit, said to that communication device sets a measurement band. The communication device according to any one of claims 1 to 3,
The band setting unit, depending on the quality of the data communicated by the packet communication unit, wherein the measurement zone to set the communication apparatus. The communication device according to any one of claims 1 to 4,
The band setting unit, the measured bandwidth communication device to set the upper or lower limit of. The communication device according to any one of claims 1 to 5,
The band setting unit, in response to said transmission direction in the transmission path, wherein to that communication device sets a measurement band. The communication device according to any one of claims 1 to 6,
The packet communication unit is a communication device that transmits the first packet within a predetermined time from the transmission of the second packet. The communication device according to any one of claims 1 to 7,
The packet generation unit generates the first packet and the second packet according to a packet size according to a bandwidth estimation method adopted by the communication device,
The said packet communication part is a communication apparatus which transmits a said 1st packet and a said 2nd packet according to the transmission interval according to the band estimation system which the said communication apparatus employ | adopts. The communication device according to claim 8,
The packet generator generates the first packet by sequentially changing a transmission rate,
The packet communication unit is a communication device that sequentially transmits the first packet and the second packet. A communication device that communicates with other communication devices via a transmission path,
A plurality of first packets having a transmission rate generated by the other communication device according to the band estimation method of the transmission path is equal to or higher than a predetermined rate, and the transmission rate generated by the other communication device is A packet communication unit that receives a second packet having a predetermined rate or less;
A bandwidth estimation unit that estimates an available bandwidth of the transmission path based on reception results of the first packet and the second packet by the packet communication unit;
Equipped with a,
The bandwidth estimation unit estimates a usable bandwidth of the transmission path based on a reception time and a scheduled reception time of the first packet and a reception time and a scheduled reception time of the second packet . The communication device according to claim 10 ,
The bandwidth estimation unit includes a first time that is a difference between a reception time of the first packet and a scheduled reception time of the first packet, a reception time of the second packet, and the second packet. A communication device that estimates an available bandwidth of the transmission path based on a second time that is a difference from a scheduled reception time. The communication device according to claim 11 ,
The bandwidth estimation unit is configured to transmit the third communication device transmitted by the other communication device a predetermined number of times before a third time that is a difference between the first time and the second time becomes equal to or greater than a predetermined threshold. A communication device that estimates an available bandwidth of the transmission path based on a transmission rate of one packet. The communication device according to any one of claims 10 to 12 ,
The band estimation unit, based on the information of the transmission pattern of the first packet and the second packet by the other communication device, and the reception time of the first second packet by the packet communication unit, A communication apparatus for deriving at least one of a scheduled reception time of a first packet and a scheduled reception time of the second packet. The communication device according to claim 12 , further comprising:
A communication apparatus comprising a threshold setting unit that sets the predetermined threshold according to the wireless type of the transmission path. The communication device according to claim 12 , further comprising:
A communication apparatus comprising a threshold setting unit configured to set the predetermined threshold according to a transmission direction in the transmission path. A communication system in which a first communication device and a second communication device communicate via a transmission line,
The first communication device is:
A packet generation unit that generates a plurality of first packets having a transmission rate equal to or higher than a predetermined rate according to a bandwidth estimation method of the transmission path, and generates a second packet whose transmission rate is equal to or lower than the predetermined rate;
A first packet communication unit that transmits the second packet generated by the packet generation unit, and transmits the first packet after transmission of the second packet;
A bandwidth setting unit for setting a measurement bandwidth for estimating the available bandwidth of the transmission path;
With
The first packet communication unit transmits the first packet and the second packet according to the measurement band,
The second communication device is:
A second packet communication unit that receives the plurality of first packets and the second packet;
A bandwidth estimation unit that estimates an available bandwidth of the transmission path based on reception results of the first packet and the second packet received by the second packet communication unit;
A communication system comprising: A communication method in a communication device that communicates with another communication device via a transmission path,
Generating a plurality of first packets having a transmission rate equal to or higher than a predetermined rate according to the bandwidth estimation method of the transmission path, and generating a second packet having a transmission rate equal to or lower than the predetermined rate;
A transmission step of transmitting said second packet the generated, transmitting the first packet after the transmission of the second packet,
Setting a measurement band for estimating an available band of the transmission path;
I have a,
In the transmission step, a communication method of transmitting the first packet and the second packet according to the measurement band . A communication method in a communication device that communicates with another communication device via a transmission path,
A plurality of first packets having a transmission rate generated by the other communication device according to the band estimation method of the transmission path is equal to or higher than a predetermined rate, and the transmission rate generated by the other communication device is Receiving a second packet that is less than or equal to a predetermined rate;
An estimation step of estimating an available bandwidth of the transmission path based on reception results of the received first packet and the second packet;
I have a,
In the estimating step, a communication method for estimating an available bandwidth of the transmission path based on a reception time and a scheduled reception time of the first packet and a reception time and a scheduled reception time of the second packet .

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