JP4614285B2 - Wireless link simulation apparatus, program, and method - Google Patents

Description

  The present invention relates to a radio link simulator, a program, and a method.

  Generally, when an IP packet is transmitted to a radio link, it is divided into a plurality of fragment packets by the physical layer and transmitted. The quality of the radio link is usually expressed by evaluation criteria defined in the physical layer (see, for example, Non-Patent Document 1). The evaluation criterion is, for example, the peak value / average value of the throughput of the fragment packet and the signal-to-noise power ratio that satisfies the required error rate. Such an evaluation criterion only for the physical layer is easy to separate various events that occur in the radio link, and is effective in extracting problems.

  From the viewpoint of network design, it is important to evaluate how a packet sent via a wireless link reaches each node. For this purpose, a network simulation device can be used (see, for example, Patent Document 1). The network simulation device artificially generates an event that occurs in an actual network using simulation parameters, and quantitatively performs function confirmation and performance verification. For example, in the case of VoIP (Voice over Internet Protocol) that sends voice traffic to an IP network, the simulation parameter given to the network simulation device is the transmission delay amount of the IP packet. This is because a large amount of transmission delay leads to interruption of voice. In this technique, the IP packet length and the transmission delay amount thereof are associated one-to-one.

N. Miyazaki and T. Suzuki, “A Study on Forward Link Capacity in MC-CDMA Cellular System with MMSEC Receiver”, IEICE Trans. Commun., Vo1.E88-B, N0.2, pp.585-593, Feb.2005 JP 2006-050319 A

  Since many user applications such as Web browsing and streaming playback are premised on transmission / reception of IP packets, it is important to evaluate the physical layer of the radio link from the viewpoint of the IP layer. In other words, comprehensive evaluation incorporating higher layers other than the physical layer is required.

However, according to the prior art, there is a problem that the behavior of IP traffic cannot be estimated using the evaluation result of the physical layer. Generally, in a wireless link, an IP packet is divided into fragment packets and transferred. When one IP packet is divided into N fragment packets and a constant error rate P _PHY is always given to the radio link, the error rate P _IP of the IP packet is expressed as follows.
P _IP = 1- (1-P _PHY ) ^N

  However, the fragment packet length of the fragment packet changes from moment to moment according to the reception quality state of the radio link. That is, since error resilience changes depending on the fragment length, the transmission delay of IP packets is not constant in the wireless link. For example, if the reception quality state of the wireless link is good, a fragment packet of a long size can be transmitted to the wireless link, so that the number of IP packet fragments is reduced and the transmission delay is also reduced. On the other hand, if the reception quality state of the radio link is poor, only short-sized fragment packets can be transmitted, so that the number of IP packet fragments increases and the transmission delay also increases.

  In the simulation of only the physical layer, since the IP packet fragment is not considered at all, the IP packet error rate cannot be obtained. That is, in the simulation of only the physical layer, it is not only possible to experience how a user application that transmits / receives an IP packet via a wireless link behaves, and it is also impossible to estimate an evaluation result in the IP layer.

  Therefore, the present invention provides a radio link simulator, a program, and a method capable of deriving a transmission delay of a fragment packet and delaying an IP packet according to the state of the radio link that changes every moment. Objective.

According to the present invention, in a radio link simulator connected between communication devices that actually transmit and receive upper packets,
A reception quality table that associates the reception quality value of the radio link to be simulated for each time,
A fragment length table in which a fragment quality of a fragment packet transmitted over a radio link is associated with a reception quality value;
Upper packet receiving means for receiving upper packets;
Deriving the fragment length from the reception quality value corresponding to the current time, ensuring a delay time until transmission of the fragment packet of the fragment length to the radio link is completed, derivation of the fragment length for all fragment packets of the upper packet, and A wireless link simulation means for repeatedly securing a delay time;
And an upper packet transmission means for transmitting the upper packet after the delay time of the upper packet is secured by the wireless link simulation means.

According to another embodiment of the radio link simulator of the present invention,
The radio link simulation means includes upper packet delay means, current fragment length derivation means, and fragment packet delay means,
The upper packet delay means first defines the packet length of the received upper packet as the remaining packet length, and repeats the current fragment length deriving means and the fragment packet delay means until the remaining packet length becomes 0,
The current fragment length deriving means derives the fragment length in the fragment length table from the reception quality value at the current time in the reception quality table,
The fragment packet delay means preferably secures a delay time until transmission of the fragment packet to the radio link is completed, and subtracts the fragment length from the remaining packet length.

According to another embodiment of the radio link simulator of the present invention,
Address queue group means for connecting the upper packet received by the packet receiving means to the queue for each destination address;
Scheduling means for taking out the upper packet from each address queue group means;
A plurality of radio link simulation means are provided corresponding to the address queue group means, and a fragment packet scheduling means for scheduling a fragment packet to be transmitted next to the radio link is further provided to the plurality of radio link simulation means. It is also preferable to have.

  According to another embodiment of the radio link simulator of the present invention, the fragment packet delay means generates a uniform random number value for each fragment packet, and when the random number value is less than the required error rate, the fragment packet delay means It is also preferable to further secure a delay time until the fragment packet is transmitted after being retransmitted.

According to the present invention, in a program for causing a computer mounted on a device connected between communication devices that actually transmit and receive upper packets to function as a wireless link,
A reception quality table that associates the reception quality value of the radio link to be simulated for each time,
A fragment length table in which a fragment quality of a fragment packet transmitted over a radio link is associated with a reception quality value;
Upper packet receiving means for receiving upper packets;
Deriving the fragment length from the reception quality value corresponding to the current time, ensuring a delay time until transmission of the fragment packet of the fragment length to the radio link is completed, derivation of the fragment length for all fragment packets of the upper packet, and A wireless link simulation means for repeatedly securing a delay time;
The computer is caused to function as upper packet transmitting means for transmitting the upper packet after the delay time of the upper packet is secured by the wireless link simulation means.

According to another embodiment of the program of the present invention,
The radio link simulation means includes upper packet delay means, current fragment length derivation means, and fragment packet delay means,
The upper packet delay means first defines the packet length of the received upper packet as the remaining packet length, and repeats the current fragment length deriving means and the fragment packet delay means until the remaining packet length becomes 0,
The current fragment length deriving means derives the fragment length in the fragment length table from the reception quality value at the current time in the reception quality table,
It is also preferable to cause the computer to function such that the fragment packet delay means secures a delay time until transmission of the fragment packet to the radio link is completed and subtracts the fragment length from the remaining packet length.

According to another embodiment of the program of the present invention,
Address queue group means for connecting the upper packet received by the packet receiving means to the queue for each destination address;
Scheduling means for taking out the upper packet from each address queue group means;
A plurality of radio link simulation means are provided corresponding to the address queue group means, and a fragment packet scheduling means for scheduling a fragment packet to be transmitted next to the radio link is further provided to the plurality of radio link simulation means. It is also preferred to have the computer function so that it has.

  According to another embodiment of the program of the present invention, the fragment packet delay means generates a uniform random number value for each fragment packet, and if the random number value is less than the required error rate, the fragment packet is erroneous. It is also preferable to make the computer function so as to further determine the delay time until the transmission is completed after the determination and the fragment packet is retransmitted.

According to the present invention, in a radio link simulation method in a simulation apparatus connected between communication apparatuses that actually transmit and receive upper packets,
For each time, the simulation device has a reception quality table in which the reception quality value of the radio link to be simulated is associated, and a fragment length table in which the fragment quality of the fragment packet transmitted through the radio link is associated with the reception quality value. Have
A first step of receiving an upper packet;
A second step of deriving the fragment length from the reception quality value corresponding to the current time;
A third step of ensuring a delay time until transmission of a fragment packet of a fragment length to a radio link is completed;
A fourth step that repeats the second and third steps for all fragment packets of the upper packet;
And a fifth step of transmitting the upper packet.

  According to the wireless link simulation apparatus, program, and method of the present invention, it is possible to derive a fragment packet transmission delay and delay an IP packet according to the state of the wireless link that changes from moment to moment. Thereby, it is possible to experience in a pseudo manner how a user application that transmits and receives IP packets behaves according to the state of the wireless link. This means that the radio link can be evaluated at the user application level.

  Hereinafter, the best mode for carrying out the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a system configuration diagram according to the present invention.

  According to FIG. 1, the system of the present invention includes a radio link simulator 1, a control terminal 2, a server side switching hub 3, a plurality of servers 4, a terminal side switching hub 5, and a plurality of terminals 6. Have. The server 4 simulates a content server, and the terminal 6 simulates a mobile terminal such as a mobile phone.

  The plurality of servers 4 are connected to the wireless link simulator 1 via the server side switching hub 3. The plurality of terminals 6 are connected to the radio link simulation device 1 via the terminal-side switching hub 5. The radio link simulator 1 is connected between the server-side switching hub 3 and the terminal-side switching hub 5 that actually transmit and receive IP packets, and simulates a radio link between the base station and the mobile station.

  A control terminal 2 is connected to the wireless link simulation device 1. The control terminal 2 transmits simulation parameters to the radio link simulation device 1. As simulation parameters, according to the present invention, there are a reception quality table and a fragment length table. Further, the control terminal 2 receives statistical information from the radio link simulator 1. The statistical information is output to a file or a display by the control terminal 2. The wireless link simulation device 1 may include the function of the control terminal 2.

  The radio link simulation device 1 simulates a radio link between the base station and the mobile station based on the simulation parameters received from the control terminal 2. A link transmitted from the server 4 to the terminal 6 means a downlink, and a link transmitted from the terminal 6 to the server 4 means an uplink. According to FIG. 1, the terminal 6 is divided into two groups, and the radio link simulator 1 can simulate two carriers. That is, two carrier waves in the same sector or two different carrier waves can be simulated. Also, according to FIG. 1, the server 4 and the terminal 6 are connected by a full-duplex LAN cable, and both uplink and downlink can be simulated simultaneously. Of course, the server 4 can be regarded as a counterpart terminal, and a wireless link between a terminal and a terminal such as an ad hoc network can be simulated.

  FIG. 2 is a functional configuration diagram of the radio link simulator 1 according to the present invention.

  According to FIG. 2, the radio link simulation apparatus 1 includes a higher-order packet reception unit 101, a header analysis unit 102, an address queue group 103, a radio link simulation unit 104, a reception quality table unit 105, and a fragment length table unit. 106, a control information receiving unit 107, a scheduling unit 108, an upper packet transmitting unit 109, a statistical information collecting unit 110, and a control information transmitting unit 111. These functional units may be realized by a program that causes a computer installed in the wireless link simulation device 1 to be executed.

  The upper packet receiving unit 101 receives a packet transmitted from the server 4 or the terminal 6. Specifically, a downlink packet is received from the server-side switching hub 3 and an uplink packet is received from the terminal-side switching hub 5.

  The header analysis unit 102 analyzes the header of the received packet and determines whether the packet is an IP packet or a packet other than an IP packet. Examples of packets other than IP packets include ARP (Address Resolution Protocol) packets.

  If it is determined that the packet is an IP packet, it is determined whether the packet is an uplink packet or a downlink packet. The uplink packet represents the address of the server 4 whose destination address is one, and the downlink packet represents the address of the terminal 6 whose destination address is one.

  When it is determined that the packet is other than the IP packet, the packet is notified to the upper packet transmission unit 109. Upper packet transmitting section 109 transmits the packet immediately. Therefore, packets other than IP packets are not targeted for simulation.

  The address queue group 103 includes two transmission source address queues and destination address queues for each address queue. In the address queue, information on at least the IP packet address and packet length is queued. Then, the scheduling unit 108 sequentially extracts the information from the head of the queue. By providing two address queues, both the uplink and downlink directions of the radio link can be simulated simultaneously.

  The same number of address queues as the terminal 6 are provided. When the source address (or source MAC address) of the IP packet is the terminal address, the header analysis unit 102 inserts the IP packet into the source address queue. This queuing corresponds to a case where an IP packet is transferred from the terminal to the server or from the terminal to the terminal. On the other hand, when the source address of the IP packet is a server address, the destination address is further analyzed. An IP packet is inserted into the destination address queue corresponding to the destination address. This queuing corresponds to a case where an IP packet is transferred from the server to the terminal.

  The scheduling unit 108 extracts IP packets from each of the plurality of address queue groups 103. The extracted IP packet is notified to the radio link simulation unit 104 corresponding to the terminal 6.

The reception quality table unit 105 has a table in which reception quality values of radio links to be simulated are associated with each time. Here, for example, CIR (Carrier to Interference power Ratio) is used as an index representing reception quality. This table is received from the control terminal 2 by the control information receiving unit 107.

  The reception quality table is created, for example, by offline system level simulation. In this system level simulation, by specifying conditions such as transmission method such as OFDM (Orthogona1 Frequency Division Multiplex) and MC-CDM (Multi-Carrier Code Division Multiplex), terminal position and speed, multipath propagation model, The reception quality of any wireless link can be acquired.

The fragment length table unit 107 has a table in which fragment lengths of fragment packets transmitted through the radio link are associated with each other according to the reception quality value. This table is received from the control terminal 2 by the control information receiving unit 107.

  In the above description, the reception quality table and the fragment length table are described as being received from the control terminal. However, the reception quality table and the fragment length table may be stored in advance in the radio link simulation apparatus of the present invention, or in parallel during simulation. These tables may be created.

  The radio link simulation unit 104 is provided in the same number as the terminal 6 corresponding to each address queue group 103. Accordingly, the plurality of radio link simulation units 104 for each terminal 6 operate in parallel. When transmitting the fragment packet of the IP packet extracted from the scheduling unit 108, the wireless link simulation unit 104 derives the fragment length from the reception quality value corresponding to the current time, and wirelessly transmits the fragment packet having the fragment length. A delay time until transmission is completed on the link is secured. Then, the derivation of the fragment length and the securing of the delay time are repeated for all the fragment packets of the IP packet.

  The radio link simulation unit 104 includes an upper packet delay unit 1041, a current fragment length derivation unit 1042, a fragment packet delay unit 1043, and a timer 1044. The timer 1044 counts the time, and outputs the time in fragment packet units. Further, one fragment packet scheduling unit 1045 is provided for the plurality of radio link simulation units 104.

  First, the upper packet delay unit 1041 defines the packet length of the received IP packet as the remaining packet length, and repeats the current fragment length deriving unit 1042 and the fragment packet delay unit 1043 until the remaining packet length becomes zero. As a result, the upper packet delay unit 1041 ensures a delay time until transmission of the IP packet to the wireless link is completed.

  The current fragment length deriving unit 1042 derives the fragment length in the fragment length table unit 106 from the reception quality value at the current time in the reception quality table unit 105.

  The fragment packet delay unit 1043 ensures a delay time until transmission of the fragment packet to the radio link is completed. A uniform random value is generated for each fragment packet, and when the random value is less than the required error rate, it is determined that the fragment packet is incorrect. When it is determined that the fragment packet is incorrect, a retransmission time, that is, a delay time until the transmission is completed after the retransmission is further secured. When the transmission of the fragment packet is completed, the fragment length derived by the current fragment length deriving unit 1042 is subtracted from the remaining packet length.

  The fragment packet scheduling unit 1045 determines a fragment packet to be transmitted next to the radio link. The scheduling algorithm is an existing method, and representative examples include a maximum CIR method and a proportional fairness method.

  In the maximum CIR method, an IP packet to be transmitted next is determined based on the CIR of a terminal that transmits and receives an IP packet, and control is performed so that a fragment packet of the IP packet is transmitted next. Therefore, when the maximum CIR method is used, it is necessary to list CIRs in the reception quality table 105 and the fragment length table 106.

  In the proportional fairness method, an IP packet to be transmitted next is determined based on a data rate of a terminal that transmits and receives an IP packet, and a fragment packet of the IP packet is controlled to be transmitted next. Therefore, when the proportional fairness method is used, it is necessary to list data rates in the reception quality table 105 and the fragment length table 106.

  Upper packet transmission section 109 transmits the IP packet whose transmission has been completed by scheduling section 108 and radio link simulation section 104.

  The statistical information collection unit 110 measures the number of IP packets and the packet length for each unit time, and notifies the control information transmission unit 111 of these information. The control information transmission unit 111 transmits the statistical information to the control terminal 2.

  FIG. 3 is an explanatory diagram of the delay time of the fragment packet in the present invention.

  The operation of FIG. 3 is realized by the fragment packet scheduling unit 1045 for the plurality of radio link simulation units 104, and is moving toward time progress. The upper part of FIG. 3 shows the IP packet taken out from the address queue group by the scheduling unit. The lower part of FIG. 3 shows the transmitted IP packet.

(S301) It is assumed that the scheduling unit 108 extracts the first IP packet and the second IP packet to be transmitted next from each address queue group 103. At this time, the fragment packet scheduling unit 1045 refers to the reception quality table for each IP packet and acquires the reception quality value corresponding to this time. For example, when the above-described maximum CIR method is used, the reception quality value of each IP packet is compared, and the IP packet having the maximum reception quality value is selected. Assume that the fragment packet scheduling unit 1045 performs scheduling to transmit the first IP packet having the maximum reception quality value with reference to the reception quality table.

  Next, referring to the fragment length table, the fragment length corresponding to the reception quality value of the first IP packet is acquired. Here, since the reception quality value is low, a short fragment length is selected. Then, it is assumed that the fragment packet having the fragment length is divided from the first IP packet and transmitted to the radio link.

  Assume that the fragment packet delay unit 1043 sets the required error rate to 10%. The fragment packet delay unit 1043 generates a uniform random number (any one of 1 to 100) for the fragment packet. If the random value here is 10 or more, it is assumed that the fragment packet is normally received by the terminal. Therefore, a delay time until the fragment packet is completely transmitted is secured.

  Next, it is assumed that the fragment packet scheduling unit 1045 refers to the reception quality table and schedules to transmit the second IP packet having the maximum reception quality value.

(S302) Next, referring to the fragment length table, the fragment length corresponding to the reception quality value of the second IP packet is acquired. Here, since the reception quality value is high, a long fragment length is selected. Then, it is assumed that the fragment packet having the fragment length is divided from the second IP packet and transmitted to the radio link.

  The fragment packet delay unit 1043 generates a uniform random number for the fragment packet. If the random value here is 10 or more, it is assumed that the fragment packet is normally received by the terminal. Therefore, a delay time until the fragment packet is completely transmitted is secured.

  Next, it is assumed that the fragment packet scheduling unit 1045 refers to the reception quality table and schedules to transmit the first IP packet having the maximum reception quality value.

(S303) Next, referring to the fragment length table, the fragment length corresponding to the reception quality value of the first IP packet is acquired. Here, since the reception quality value is low, a short fragment length is selected. Then, it is assumed that the fragment packet having the fragment length is divided from the first IP packet and transmitted to the radio link. It is assumed that all the first IP packets are transmitted at this stage.

  The fragment packet delay unit 1043 generates a uniform random number for the fragment packet. If the random number here is less than 10, it is assumed that the fragment packet is erroneous by the radio link. Here, the secured delay time is the time from when the fragment packet is transmitted until the response NACK is received.

(S304) Next, the fragment packet delay unit 1043 again generates a uniform random number for the fragment packet. If the random value here is 10 or more, it is assumed that the fragment packet is normally received by the terminal. Therefore, the fragment packet secures a delay time until the fragment packet is completely transmitted.

  As a result, the first IP packet is regarded as transmission completion and is transmitted from the radio link simulator 7.

  Next, it is assumed that the fragment packet scheduling unit 1045 refers to the reception quality table and schedules to transmit the second IP packet having the maximum reception quality value.

(S305) Next, referring to the fragment length table, the fragment length corresponding to the reception quality value of the second IP packet is acquired. Here, since the reception quality value is low, a short fragment length is selected.

  FIG. 4 is a flowchart of the radio link simulator in the present invention.

  The flowchart in FIG. 4 is executed by the radio link simulation unit when the scheduling unit extracts an IP packet from the address queue group.

(S401) First, a reception quality value corresponding to the current time is obtained using the reception quality table.
(S402) Next, the fragment length corresponding to the reception quality value is acquired using the fragment length table. S401 and S402 perform the same operation as the above-described current fragment length deriving unit.

(S403) The upper packet delay unit defines the packet length of the IP packet to be transmitted next as the remaining packet length.
(S404) Then, the upper packet delay unit repeats S405 to S409 until the remaining packet length becomes zero.

(S405) A uniform random value is generated for each fragment packet. This random value is, for example, one of 1 to 100.
(S406) It is determined whether the random value is less than a required error rate.
(S407) If the random number value is equal to or higher than the required error rate, the fragment length is subtracted from the remaining packet length, assuming that the terminal has normally received.
(S408) Next, a delay time until transmission of the fragment packet to the wireless link is completed is secured.
(S409) The process returns to S404 until the remaining packet length becomes zero.
(S410) If the random value is less than the required error rate, it is assumed that an error has occurred, and a delay time including the NACK response time of the fragment packet is secured. S405 to S410 perform the same operation as the fragment packet delay unit described above.

(S411) When the remaining packet reaches 0, the upper packet transmission unit transmits the IP packet.

  As described above in detail, according to the radio link simulation apparatus, program, and method of the present invention, the transmission delay of the fragment packet is derived according to the state of the radio link that changes from moment to moment, and the IP packet is Can be delayed. Thereby, it is possible to experience in a pseudo manner how a user application that transmits and receives IP packets behaves according to the state of the wireless link. This means that the radio link can be evaluated at the user application level.

  According to the various embodiments of the present invention described above, those skilled in the art can easily make various changes, modifications and omissions within the scope of the technical idea and the viewpoint of the present invention. The above description is merely an example, and is not intended to be restrictive. The invention is limited only as defined in the following claims and the equivalents thereto.

It is a system configuration diagram in the present invention. It is a functional block diagram of the radio link simulation apparatus in this invention. It is explanatory drawing of the delay time of the fragment packet in this invention. It is a flowchart of the radio link simulation part in this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Radio link simulation apparatus 101 Upper packet receiving part 102 Header analysis part 103 Address queue group 104 Wireless link simulation part 1041 Upper packet delay part 1042 Current fragment length deriving part 1043 Fragment packet delay part 1044 Timer 1045 Fragment packet scheduling part 105 Reception quality table Unit 106 fragment length table unit 107 control information receiving unit 108 scheduling unit 109 upper packet transmitting unit 110 statistical information collecting unit 111 control information transmitting unit 2 control terminal 3 server side switching hub 4 server 5 terminal side switching hub 6 terminal

Claims (9)

In a wireless link simulator connected between communication devices that actually transmit and receive upper packets,
A reception quality table that associates the reception quality value of the radio link to be simulated for each time,
A fragment length table in which a fragment length of a fragment packet transmitted through the radio link is associated with the reception quality value;
Upper packet receiving means for receiving the upper packet;
Deriving the fragment length from the reception quality value corresponding to the current time, securing a delay time until transmission of the fragment packet of the fragment length to the radio link is completed, and for all the fragment packets of the upper packet, the fragment length Wireless link simulation means for repeatedly deriving and securing the delay time;
A radio link simulation apparatus comprising: upper packet transmission means for transmitting the upper packet after a delay time of the upper packet is secured by the radio link simulation means. The radio link simulating means has upper packet delay means, current fragment length derivation means, and fragment packet delay means,
The upper packet delay means first defines the packet length of the received upper packet as a remaining packet length, and repeats the current fragment length deriving means and the fragment packet delay means until the remaining packet length becomes zero ,
The current fragment length deriving means derives the fragment length in the fragment length table from the reception quality value at the current time in the reception quality table,
2. The fragment packet delay means secures a delay time until transmission of the fragment packet to the radio link is completed, and subtracts the fragment length from the remaining packet length. Wireless link simulator. Address queue group means for connecting the upper packet received by the packet receiving means to a queue for each destination address;
Scheduling means for taking out the upper packet from each address queue group means;
A plurality of the radio link simulating means are provided corresponding to the address queue group means, and a fragment packet scheduling means for scheduling a fragment packet to be transmitted to the radio link next to the plurality of radio link simulating means. The radio link simulator according to claim 2, further comprising:   The fragment packet delay means generates a uniform random value for each fragment packet, and determines that the fragment packet is incorrect when the random value is less than the required error rate, and completes transmission after the fragment packet is retransmitted. The radio link simulator according to claim 2 or 3, further comprising a delay time up to In a program for causing a computer mounted on a device connected between communication devices that actually transmit and receive upper packets to function as a wireless link,
A reception quality table that associates the reception quality value of the radio link to be simulated for each time,
A fragment length table in which a fragment length of a fragment packet transmitted through the radio link is associated with the reception quality value;
Upper packet receiving means for receiving the upper packet;
Deriving the fragment length from the reception quality value corresponding to the current time, securing a delay time until transmission of the fragment packet of the fragment length to the radio link is completed, and for all the fragment packets of the upper packet, the fragment length Wireless link simulation means for repeatedly deriving and securing the delay time;
A radio link simulation program for causing a computer to function as upper packet transmission means for transmitting the upper packet after the delay time of the upper packet is secured by the radio link simulation means. The radio link simulating means has upper packet delay means, current fragment length derivation means, and fragment packet delay means,
The upper packet delay means first defines the packet length of the received upper packet as a remaining packet length, and repeats the current fragment length deriving means and the fragment packet delay means until the remaining packet length becomes zero ,
The current fragment length deriving means derives the fragment length in the fragment length table from the reception quality value at the current time in the reception quality table,
The fragment packet delay means secures a delay time until transmission of the fragment packet to the radio link is completed, and causes the computer to function so as to subtract the fragment length from the remaining packet length. The wireless link simulation program according to claim 5. Address queue group means for connecting the upper packet received by the packet receiving means to a queue for each destination address;
Scheduling means for taking out the upper packet from each address queue group means;
A plurality of the radio link simulating means are provided corresponding to the address queue group means, and a fragment packet scheduling means for scheduling a fragment packet to be transmitted to the radio link next to the plurality of radio link simulating means. The wireless link simulation program according to claim 6, wherein the computer is caused to function so as to further include:   The fragment packet delay means generates a uniform random value for each fragment packet, and determines that the fragment packet is incorrect when the random value is less than the required error rate, and completes transmission after the fragment packet is retransmitted. The wireless link simulation program according to claim 6 or 7, wherein the computer is caused to function so as to further secure a delay time until the transmission time. In a wireless link simulation method in a simulation device connected between communication devices that actually transmit and receive upper packets,
The simulation apparatus includes a reception quality table in which a reception quality value of a wireless link to be simulated is associated with each reception time, and a fragment length in which a fragment length of a fragment packet transmitted through the wireless link is associated with the reception quality value. A table and
A first step of receiving the upper packet;
A second step of deriving the fragment length from the reception quality value corresponding to the current time;
A third step of ensuring a delay time until transmission of the fragment packet of the fragment length to the radio link is completed;
A fourth step of repeating the second and third steps for all fragment packets of the upper packet;
And a fifth step of transmitting the upper packet.

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