JP3759734B2 - COMMUNICATION SYSTEM, COMMUNICATION DEVICE, AND COMMUNICATION METHOD - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a communication system, a communication apparatus, and a communication method for an ad hoc wireless network that includes a plurality of wireless stations and performs packet communication in an ad hoc wireless network, for example.
[0002]
[Prior art]
In an ad hoc wireless network that wirelessly supports communication between an unspecified number of people who temporarily gathered in a specific area, there is no infrastructure such as an Internet router device, so users in the network cannot It is necessary to relay packets in cooperation and perform routing.
[0003]
As routing of an ad hoc wireless network, for example, Non-Patent Document 1 proposes a method for obtaining route information by transmitting a route search packet (hereinafter referred to as a first conventional example).
[0004]
However, in the first conventional example, since an omnidirectional antenna is used, co-channel interference is likely to occur, the bit error rate (BER) increases, the power consumption during packet transmission / reception increases, and the terminal device There is a problem that the load on the battery becomes high. In order to solve this problem, in Patent Document 1, “in a routing method for a wireless network that includes a plurality of wireless stations and performs packet communication between the wireless stations, the service area of the plurality of wireless stations” The interference noise for each predetermined azimuth angle is measured in advance and stored in the storage device as an interference noise table, and when the packet is transmitted to the destination wireless station, one hop is generated based on the interference noise table. For the wireless network that determines the first radio station and routes the packet by controlling the omni antenna and transmitting the packet to form a beam for the determined first hop radio station. Routing method (hereinafter referred to as a second conventional example) has been proposed.
[0005]
An important feature of these ad hoc wireless networks is the ability to instantly start wireless communication between wireless terminal devices. For example, in an infrared communication method such as IrDA, it is necessary to secure a line of sight between transmission / reception terminal devices. The wireless LAN system is widely used. Bluetooth can realize a transmission distance of 10 m, and IEEE 802.11. In the wireless LAN system compliant with b, transmission up to 250 m is possible. When a certain node radio station tries to communicate with another node radio station located beyond the transmission distance, this node radio station transmits the data to a node radio station closer to the destination and relays it. Each node radio station in an ad hoc radio network participates in the formation of a network topology when it spontaneously transmits radio packet traffic. For example, a data packet transmitted from point A to point B can hop to several other node radio stations without the user's knowledge.
[0006]
[Patent Document 1]
Japanese Patent Laid-Open No. 2001-244983.
[Non-Patent Document 1]
DB Johnson, et al., "Dynamic Source Routing in Ad Hoc Wireless Networks", in book on "Mobile Computing", Chapter 5, pp.153-181, Kluwer Academic Publishers, 1996.
[Non-Patent Document 2]
Manolis Katevenis et al., “Weighted Round-Robin Cell Multiplexing in a General-Purpose ATM Switch Chip”, IEEE Journal on Selected Areas in Communications, Vol. 9, No. 8, October 1991.
[Non-Patent Document 3]
Kenjiro Cho, “QoS Control Technology on the Internet-Diffserv”, Internet Week 99, Pacifico Yokohama, Japan Network Information Center, December 14, 1999.
[Non-Patent Document 4]
Scalable Networks Technologies, QualNet 3.5, [Search April 3, 2003], Internet <URL: http://www.scalable-networks.com/>.
[0007]
[Problems to be solved by the invention]
For example, in an ad hoc wireless network that includes 30 or more active mobile host radio stations, the user's mobile host radio station can be a router that performs several simultaneous connections, and therefore is The bandwidth for occupying the majority and performing communication originating from the local station is greatly limited. Currently, the user cannot adjust the bandwidth of the mobile host radio station provided as a relay router device to the ad hoc radio network. The bandwidth is evenly distributed among all communications regardless of whether the communications are originating from the local station. There is a problem that the user may soon encounter a serious decrease in communication speed due to communication originating from many other stations using the mobile host radio station as a relay router device. there were.
[0008]
The object of the present invention is to solve the above-mentioned problems, and in an ad hoc wireless network, immediately encounters a serious decrease in communication speed due to many other station-originated communications using node radio stations as routers. It is an object of the present invention to provide a communication system, a communication apparatus, and a communication method for an ad hoc wireless network that can prevent the above-described problem and increase the throughput of each wireless station.
[0009]
[Means for Solving the Problems]
A communication system according to a first aspect of the present invention is a communication system for an ad hoc wireless network that includes a plurality of wireless stations and performs packet communication between the wireless stations.
Two queue memories having different priorities with a predetermined weighting factor ratio are provided, and when a packet to be transmitted to another station is a packet originated from the own station, it is inserted into a queue memory having a higher priority and transmitted. In addition, when a packet to be transmitted to another station is a packet originated from another station, control means is provided for controlling the packet to be inserted into a queue memory having a lower priority and relayed.
[0010]
The communication system further includes means for inputting and setting the weighting coefficient ratio.
[0011]
Further, in the communication system, the control means controls to read and transmit packets from the two queue memories using a weighted round robin method.
[0012]
A communication device according to a second aspect of the present invention is a communication device for an ad hoc wireless network that includes a plurality of wireless stations and performs packet communication between the wireless stations.
Two queue memories having different priorities with a predetermined weighting factor ratio are provided, and when a packet to be transmitted to another station is a packet originated from the own station, it is inserted into a queue memory having a higher priority and transmitted. In addition, when a packet to be transmitted to another station is a packet originated from another station, control means is provided for controlling the packet to be inserted into a queue memory having a lower priority and relayed.
[0013]
The communication apparatus may further include means for inputting and setting the weighting coefficient ratio.
[0014]
Further, in the communication apparatus, the control means controls to read and transmit packets from the two queue memories using a weighted round robin method.
[0015]
A communication method according to a third aspect of the present invention is a communication method for an ad hoc wireless network that includes a plurality of wireless stations and performs packet communication between the wireless stations.
In a communication apparatus including two queue memories having different priority levels with a predetermined weighting factor ratio, when a packet to be transmitted to another station is a packet originated from the own station, the packet is inserted into a queue memory having a higher priority level. And a control step for controlling to insert into a queue memory having a lower priority when the packet to be transmitted to another station is a packet originated from another station, and to perform relay transmission. And
[0016]
The communication method further includes a step of inputting and setting the weighting coefficient ratio.
[0017]
Furthermore, in the communication method, the control step performs control so that packets are read from the two queue memories and transmitted using a weighted round robin method.
[0018]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments according to the present invention will be described below with reference to the drawings.
[0019]
FIG. 1 is a plan layout view of a plurality of radio stations 1-1 to 1-9 (generally referred to by reference numeral 1) showing a configuration of an ad hoc radio network according to an embodiment of the present invention. In the wireless communication system of this embodiment, as shown in FIG. 1, a plurality of wireless stations 1 are present in a plane and each wireless station 1 has a gain, transmission power, reception sensitivity, etc. of the omni antenna 101. A predetermined service area determined by the parameters, and can perform packet communication within the service area. When performing packet communication with the wireless station 1 outside the service area, the wireless station 1 within the service area is The packet data is transmitted to the desired destination radio station 1 by relaying the packet data using it as a relay station.
[0020]
FIG. 2 is a block diagram showing an internal configuration of each radio station 1 of FIG. The wireless communication system of this embodiment is applied to a packet communication system of an ad hoc wireless network such as a wireless LAN, for example, and is particularly characterized by including the router device 105 shown in FIGS. Here, as shown in FIG. 3, the router device 105 includes a queue manager 212 and two queue memories 213 and 214 having different priorities, and the queue manager 212 is a packet originated from its own station. In some cases, the queue manager 212 inserts and stores the queue in the queue memory 213 having a higher priority, while the queue manager 212 inserts the packet into the queue memory 214 having a lower priority when the input packet is a packet originating from another station. Store. That is, each wireless station 1 includes a router device 105 that performs packet routing, and operates as a transmission terminal, a relay station, or a destination terminal.
[0021]
Next, a relay service policy of an ad hoc wireless network using a queue having two priorities used in the present embodiment will be described.
[0022]
As described in the section of the prior art, the user of each radio station 1 cannot adjust the bandwidth of the mobile host radio station provided as a relay router device in the ad hoc radio network. However, if each wireless station 1 has the ability to prioritize by distinguishing between communication originating from the local station and communication originating from other stations, it is possible to enhance the control of the behavior of the local station device. Flexibility can be increased. In that case, each wireless station 1 can arbitrarily allocate more bandwidth to the communication originating from the local station when necessary, and at the same time, when the local station device is not in use, more bandwidth can be allocated. Can be assigned to communications originating from other stations.
[0023]
In order to achieve these functions, we propose to implement service prioritization at the link layer of the mobile host radio station. In particular, to realize this function, we propose a new framework that uses a two-queue approach to the one-queue approach according to the prior art. In prior art designs, packets are inserted into one queue regardless of where the packet originates. For example, if a mobile host radio station is used as a relay router device by some third party communication, the queue of IP packets will be congested accordingly and may start to drop packets . If the user of the mobile host radio station makes a communication call at this point, additional load is added to the already congested queue, thus making the congestion even more severe. In order to ensure that this situation does not occur and that the user's own communication always has a higher priority than the communication by a third party, the inventors have introduced a two-queue approach to improve the situation. Yes. One of the two queues is used to hold only packets from the communication originating from the own station, and the other queue is used to hold packets from communication originating from the other station. All of these are queues based on RED (Random Early Detection) based on ECN (Explicit Congestion Notification) defined in RFC2481 of the Internet. If the packet is discarded, the sender can be notified. By providing two queues, packet drops or ECN calls in one queue only affect senders that insert packets into that queue, and transmissions using other queues at the same node radio station Guarantee that it will not affect A scheduler based on Weighted Round-Robin (hereinafter referred to as a WRR scheduler; see, for example, Non-Patent Document 2) is used to adjust the weighting factor of a queue between two queues. ing. For example, if one queue is weighted more heavily than the other queue, multiple packets are processed in that queue, and more packets flow out of that queue, increasing throughput.
[0024]
Next, a framework related to queue control will be described. In the following, the RED and WRR scheduler algorithms used in the present embodiment will be briefly described.
[0025]
In the RED algorithm with ECN enabled, the RED gateway device calculates the average queue size and compares it to two thresholds, the maximum and minimum thresholds. If the average queue size is below the minimum threshold, ECN does not mark any packets. If the average queue size is between the maximum and minimum thresholds, a predetermined probability is marked on the incoming packet. When the average queue size exceeds the maximum threshold and hence the marking speed capability of the packet increases, the router device drops the packet rather than setting the CE bit (Congestion Experienced bit) in the packet header. There is. ECN provides a mechanism for the router device to send an indication of congestion directly to the source radio station. According to Internet RFC2481, ECN requires two bits in the IP header and two new flags in the TCP header. The ECT bit (ECN-Capable Transport bit) is set by the sender and indicates that the endpoint of the transport layer protocol is ECN compatible. Next, using the RED algorithm, it is determined whether the router device should set the CE bit (Congestion Experienced bit) to indicate congestion. When receiving a data packet with the CE bit marked, the data receiver sets an ECN echo flag to notify the data sender of the congestion. A CWR (Congestion Window Reduced) is assigned so that the data receiver can decide when to stop setting the ECN echo flag (see, for example, Non-Patent Document 3).
[0026]
The WRR scheduler services each priority queue sequentially in a predetermined order. The number of turns a queue is serviced in one cycle depends on the weighting factor of that queue. For example, WRR will service many turns to a priority queue with a large weighting factor. The WRR services the scheduled number of packets starting from the first queue that contains the packet, then moves to the next queue that contains the packet and waits for each queue that has a packet until it is serviced. Serve a single packet from a matrix.
[0027]
Further, a prioritized communication method using a queue having two priorities will be described below.
[0028]
The queue with priority in which the packet is inserted is determined by comparing the IP source address with the address of the local node. If the IP source address is equal to the address of its own node, the packet is a naturally occurring packet and is inserted into the queue memory 213, which is the first priority queue. On the other hand, if the IP source address and the address of the local node do not match, the packet is inserted into the queue memory 214 which is a second priority queue. Small modifications have been made in the IP service type field (TOS field) to ensure that packets are inserted into the correct priority queue.
[0029]
FIG. 5 is a diagram showing a format of the TOS field used in the wireless station 1 of FIG. Bit 6 (ECT) and bit 7 (CE) in the IP TOS field are unchanged, ensuring that the ECN operates under this embodiment by the inventors. Bits 4 and 5 have been modified to display a queue having the priority in which the packet is inserted and are referred to as “queue memory designation bits”. That is, when the queue memory designation bit is 01, the packet is inserted into the queue memory 213 of the first priority, and when the queue memory designation bit is 00, the packet is the queue memory 214 of the second priority. Inserted into. This modification made by the inventors is not backward compatible with the Diffserv method (see, for example, Non-Patent Document 3).
[0030]
Next, the device configuration of each radio station 1 will be described with reference to FIG. In FIG. 2, the wireless station 1 includes an omni antenna 101, a circulator 102, a data packet transmission / reception unit 103 having a data packet transmission unit 140 and a data packet reception unit 130, a line control unit 104, a router device 105, A layer processing device 106.
[0031]
The upper layer processing apparatus 106 generates communication data (hereinafter referred to as a packet) in a packet format to be transmitted from the own station, and receives and processes a packet received by the own station. The packet generated by the upper layer processing apparatus 106 is input to the modulator 143 via the router apparatus 105 and the transmission buffer memory 142, which will be described in detail later with reference to FIG. 3, and the modulator 143 receives a carrier wave of a predetermined radio frequency. The signal is subjected to spread spectrum modulation in accordance with the input packet using a predetermined communication channel spreading code generated by the spreading code generator 160 by the CDMA method, and the modulated transmission signal is output to the high frequency transmitter 144. . The high-frequency transmitter 144 performs processing such as amplification on the input transmission signal, and then transmits the signal from the omni antenna 101 to another wireless station 1 via the circulator 102. On the other hand, the communication signal received in the packet format received by the omni antenna 101 is input to the high frequency receiver 131 through the circulator 102, and the high frequency receiver 131 performs low noise amplification or the like on the input received signal. After executing the processing, the result is output to the demodulator 132. The demodulator 132 demodulates the input received signal by spectrum despreading using the communication channel spreading code generated by the spread code generator 160 by the CDMA method, and receives the demodulated received signal data packet. Is output to the upper layer processing apparatus 106 via the reception buffer memory 133 and the router apparatus 105.
[0032]
The line control unit 104 determines a time slot corresponding to a communication channel to be used for transmission / reception using a predetermined line control method, and sends the designated data to the transmission timing control unit 141, thereby transmitting the transmission timing control unit 141. Controls transmission and reception of packets by the transmission buffer memory 142 so that the packets to be transmitted are transmitted in the corresponding time slots, and the packets to be received are spread so as to be received in the predetermined time slots. The code generator 160 is controlled.
[0033]
FIG. 3 is a block diagram showing an internal configuration of the router device 105 of FIG. 3, the packet received by the packet transmitting / receiving unit 103 in FIG. 2 is input from the reception buffer memory 133 to the local address identifier 211 of the router device 105, and the local address identifier 211 receives the IP of the input packet. It is determined whether or not the source address is the IP address of the local station. When the source address is the IP address of the local station, the packet is output to the upper layer processing device 106, while when it is the IP address of the other station The packet is output to the queue manager 212. The queue manager 212 is controlled by the routing controller 200, receives a packet from the local address identifier 211 or the upper layer processing apparatus 106, and executes the queue management process of FIG. When the address is the IP address of the own station, it is inserted and stored in the queue memory 213. On the other hand, when the IP source address of the received packet is the IP address of another station, it is inserted and stored in the queue memory 214. To do.
[0034]
The routing controller 200 includes, for example, a keyboard 201 which is an input means for inputting a weighting coefficient ratio for determining the priority of transmission output processing for the two queue memories 214 and 213 in the scheduler 210 using a WRR scheduler method, and the input A liquid crystal display 202 that displays information on the weighted coefficient ratio is connected. When the user of the wireless station 1 inputs the weighting coefficient ratio for the two queue memories 214 and 213 using the keyboard 201, the information is input and set to the scheduler 210 via the routing controller 200. In this embodiment, the weighting coefficient ratio is a weighting coefficient ratio with respect to the queue memories 214 and 213, and is represented by (x, y). In this embodiment, the priority order of the queue memory 213 is the priority order of the queue memory 214. Therefore, it is set as follows.
[0035]
[Expression 1]
x <y
here,
[Expression 2]
x + y = 1.0
[0036]
The scheduler 210 controlled by the routing controller 200 uses the known WRR scheduler method and switches the switch 215 with the input weighting factor ratio, and sequentially reads out packets from the two queue memories 213 and 214 and transmits them. Output to the memory 142 and transmit.
[0037]
FIG. 4 is a flowchart showing a queue management process executed by the queue manager 212 of FIG. In FIG. 4, it is determined whether or not a packet has arrived in step S1, and step S2 is repeated until YES is obtained. It is determined whether or not there is, and if YES, the process proceeds to step S3, whereas if NO, the process proceeds to step S4. In step S3, 01 is inserted into the queue memory designation bit of the packet, and the process proceeds to step S5. On the other hand, in step S4, 00 is inserted into the queue memory designation bit of the packet, and the process proceeds to step S5. In step S5, after arriving at the queue memory 213 or 214 corresponding to the queue memory designation bit and storing it, the process returns to step S1. Here, when the queue memory designation bit is 01, the packet is inserted and stored in the queue memory 213 having a higher priority, and when the queue memory designation bit is 00, the packet has a higher priority. It is inserted into the low queue memory 214 and stored.
[0038]
【Example】
Next, the inventors performed simulation as follows using the communication system of the ad hoc wireless network according to the present embodiment, and obtained the following simulation results.
[0039]
The simulation was performed using a network simulator of Qualnet 3.1 (for example, see Non-Patent Document 4) commercially available from Scalable Network Technologies. All simulation results are average values of 100 simulation runs performed using different random numbers. Table 1 shows the parameters used in our simulation.
[0040]
[Table 1]
―――――――――――――――――――――――――――――――――――
Propagation model Two-wave terrestrial model
―――――――――――――――――――――――――――――――――――
MAC IEEE 802.11
―――――――――――――――――――――――――――――――――――
Transmission bandwidth 2Mbps
―――――――――――――――――――――――――――――――――――
Antenna type Omni antenna
―――――――――――――――――――――――――――――――――――
Queue type RED
―――――――――――――――――――――――――――――――――――
Queue memory size 50k bytes
―――――――――――――――――――――――――――――――――――
Maximum threshold of RED 15 pkts
―――――――――――――――――――――――――――――――――――
Minimum threshold of RED 25 pkts
―――――――――――――――――――――――――――――――――――
Scheduler WRR method
―――――――――――――――――――――――――――――――――――
Routing protocol AODV (On Demand Distance Vector)
―――――――――――――――――――――――――――――――――――
TCP type TCP / Reno
―――――――――――――――――――――――――――――――――――
TCP packet size 512 bytes
―――――――――――――――――――――――――――――――――――
[0041]
FIG. 6 shows the network topology used in the simulation. Here, all the node radio stations are fixed, and all communication is performed wirelessly by an ad hoc wireless network. In our simulation, the maximum bandwidth of the radio link is 2 Mbps. All node radio stations 1 are provided with queue memories 213 and 214 of two RED queues, and all are ECN enabled. The routing protocol is AODV and uses a WRR scheduler.
[0042]
As shown in FIG. 6, between the node radio station 1-1 and the node radio station 1-3, there is 2-hop TCP communication that requires a hop to the node radio station 1-2. In this case, the node radio station 1-1 regards this radio communication as a communication originated from its own station, and therefore inserts all of its own packets into the queue memory 213 that is its first queue. However, when packets from the node radio station 1-1 reach the node radio station 1-2, these packets are not transmitted by the node radio station 1-2, but are transmitted by the node radio station 1-2. Since it is considered as communication, the node radio station 1-2 inserts all these packets into its second queue, the queue memory 214. On the other hand, TCP communication between the node radio station 1-2 and the node radio station 1-4 is established simultaneously with TCP communication from the node radio station 1-1 to the node radio station 1-3. At this time, since the node radio station 1-2 regards this radio communication as communication originated from itself, it inserts all the packets that it issues into the queue memory 213 that is the first queue. At the same time, there are two wireless communications, one of which follows the node wireless station 1-2, originating from the own station and the other originating from the other station, but the packets from the two wireless communications are queue memories 213, which are two different queues. 214 successfully separated.
[0043]
In such a method, the TCP throughput from the node radio station 1-2 to the node radio station 1-4 is essentially due to the difference in operation between the 1-hop radio communication and the 2-hop radio communication. Becomes larger than the throughput of TCP from the node radio station 1-1 to the node radio station 1-3. FIG. 7 illustrates a simulation setup in Qualnet according to the embodiment.
[0044]
Our simulations also include a prior art one-queue severe approach for operation comparison. Other results were obtained by changing the weighting factor ratio of the two queues in the WRR scheduler. For example, the weighting coefficient ratio (0.5, 0.5) on the x-axis in the graphs of FIGS. 8 and 9 indicates that the queue memories 213 and 214, which are queues having two priorities, have the same weighting coefficient. The weighting coefficient ratio (0.4, 0.6) indicates that the weighting coefficient is biased toward the communication originating from the local station. Here, the two weighting coefficients must be 1 in total as shown in the above equation 2. The weighting coefficient ratio (0.3, 0.7) means that the weighting coefficient of the queue is further biased toward the communication transmitted from the own station. It should be noted that this situation is unlikely to occur when the weighting factor of the queue for the communication queue originating from other stations is heavier than the weighting factor of the queue for the communication queue originating from the local station. Not considered.
[0045]
FIG. 8 shows a comparison of throughput between two TCP communications (node radio station 1-1 to node radio station 1-3 and node radio station 1-2 to node radio station 1-4). Since the communication from the node radio station 1-2 to the node radio station 1-4 is a one-hop radio communication, the throughput is essentially two-hop from the node radio station 1-1 to the node radio station 1-3. Faster than wireless communication, the result with one queue memory in FIG. 8 clearly reflects this fact. If an approach using two queues is introduced (starting from the weighting factor ratio (0.5, 0.5)), the weighting factor of the queue for the communication queue originating from the local station increases, so that the node radio station The throughput from 1-2 to the node radio station 1-4 increases. This is because the node radio station 1-2 communicates with other stations (in this case, the node radio station 1-1 as the weighting coefficient of the queue for the communication queue of the local station originates in the node radio station 1-2 increases. This is because more bandwidth is allocated to the own TCP communication than communication from the node wireless station 1-3 to the node wireless station 1-3, resulting in an increase in throughput.
[0046]
FIG. 9 shows the total bandwidth combining two TCP communications. The upward slope of the graph of FIG. 9 can be explained by our experimental setup. As described above, since only one hop is required for communication from the node radio station 1-2 to the node radio station 1-4, the communication from the node radio station 1-1 to the node radio station 1-3 is essentially performed. Will also have a high throughput. In this experiment, more throughput is expected for the faster communication method. Therefore, if the throughput of the slower communication is lowered, the combined throughput naturally increases. In the case of the weighting coefficient ratio (0.5, 0.5), the node radio station 1-2 generates a packet how fast it is for its own transmission (from the node radio station 1-2 to the node radio station 1-4). Even so, the weighting factor of the queue for the communication queue originating from the local station is limited to be the same as the weighting factor of the queue for the communication queue originating from the other station. For this reason, the throughput of communication from the fast node radio station 1-2 to the node radio station 1-4 is essentially reduced, resulting in a reduction in the combined total throughput.
[0047]
As described above, as the number of computers in an ad hoc wireless network increases, the mutual communication between computers becomes extremely complicated. Therefore, the user can reduce the bandwidth between the communication originating from the local station and the communication originating from the other station. It is necessary to implement functions that can be adjusted. In the present embodiment, a routing method using two queue queue memories 213 and 214 for distinguishing between communication originating from the local station and communication originating from other stations and giving priority to both has been proposed. Through the use of the Qualnet 3.1 simulator, dramatic throughput results have been obtained for prioritized and non-prioritized communications. As FIG. 8 shows, the prioritized direct wireless communication can produce approximately 40% more throughput than the non-prioritized wireless communication. Further, as the weighting coefficient of the queue for the radio communication originating from the local station increases, the throughput for the radio communication originating from the local station increases appropriately and proportionally. Based on all the results obtained, the inventors are convinced that the inventors' examples are fulfilled for the intended purpose.
[0048]
In the above embodiment, the WRR method is used. However, the present invention is not limited to this, and other scheduler methods such as WDRR (Weighted Deficit Round Robin) may be used.
[0049]
【The invention's effect】
As described above in detail, according to the communication system, communication apparatus, or communication method according to the present invention, in an ad hoc wireless network that includes a plurality of wireless stations and performs packet communication between the wireless stations, each other with a predetermined weighting factor ratio. In a communication apparatus including two queue memories having different priorities, when a packet to be transmitted to another station is a packet originated from the own station, the packet is inserted into a queue memory having a higher priority and transmitted. When the packet to be transmitted to is a packet originated from another station, it is inserted into a queue memory having a lower priority and controlled to be relayed. Therefore, it is possible to prevent a serious decrease in the communication speed due to many other station originating communications using the node radio station as a relay router device, and increase the throughput of each radio station. it can. Further, by inputting and setting the weighting coefficient ratio, the priority order of the two queue memories can be changed, and the throughput desired by the user can also be changed.
[Brief description of the drawings]
FIG. 1 is a plan layout view of a plurality of radio stations 1-1 to 1-9 constituting an ad hoc radio network according to an embodiment of the present invention.
2 is a block diagram showing an internal configuration of each radio station 1 in FIG. 1. FIG.
FIG. 3 is a block diagram showing an internal configuration of the router device 105 of FIG. 2;
4 is a flowchart showing queue management processing executed by the queue manager 212 of FIG.
5 is a diagram showing a format of a TOS field used in the wireless station 1 of FIG.
FIG. 6 is a plan view showing the topology used in the simulation of the ad hoc wireless network in the example according to the present embodiment.
FIG. 7 is a plan view showing a Qualnet topology used in an ad hoc wireless network simulation in an example according to the present embodiment;
FIG. 8 is a simulation result of an ad hoc wireless network in an example according to the present embodiment, in which the wireless station 1-1 with respect to the weighting coefficient ratio of WRR for one queue memory and two queue memories 214 and 213; 4 is a graph showing the throughput of packet communication from the wireless station 1-3 to the wireless device 1-3 and packet communication from the wireless station 1-2 to the wireless station 1-4.
FIG. 9 is a simulation result of the ad hoc wireless network in the example according to the present embodiment, in which the throughput of the server apparatus with respect to the weighting coefficient ratio of WRR for one queue memory and two queue memories 214 and 213; It is a graph which shows the throughput of a client apparatus.
[Explanation of symbols]
1, 1-1 to 1-9 ... wireless station,
101 ... Omni antenna,
102 ... circulator,
103 ... Packet transmission / reception unit,
104 ... line control unit,
105: Router device,
106 ... upper layer processing apparatus,
130: Packet receiver,
131 ... high frequency receiver,
132: demodulator,
133: Receive buffer memory,
140 ... packet transmitter,
141. Transmission timing control unit,
142 ... transmission buffer memory,
143 ... modulator,
144 ... high frequency transmitter,
160. Spread code generator.
200 ... Routing controller,
201 ... Keyboard,
202 ... Liquid crystal display,
210 ... scheduler,
211 ... Local address identifier,
212 ... Queue manager,
213, 214 ... Queue memory,
215 ... Switch.

Claims (9)

In a communication system for an ad hoc wireless network that includes a plurality of wireless stations and performs packet communication between the wireless stations,
Provided in the preceding stage of the transmission buffer, receive packets to be transmitted, and receive packets having different priorities with a predetermined weighting factor ratio, and the first queue memory has a higher priority than the second queue memory. First and second queue memories for storing to have
It is determined whether or not the source address of the packet to be transmitted is the local station address, and when it is the local station address, the packet is inserted into the first queue memory and transmitted through the transmission buffer. And a control means for controlling to insert into the second queue memory and transmit via the transmission buffer when not .   The communication system according to claim 1, further comprising means for inputting and setting the weighting coefficient ratio.   3. The communication system according to claim 1, wherein the control means performs control so that packets are read from the two queue memories and transmitted using a weighted round robin method. In a communication device for an ad hoc wireless network that includes a plurality of wireless stations and performs packet communication between wireless stations,
Provided in the preceding stage of the transmission buffer, receive packets to be transmitted, and receive packets having different priorities with a predetermined weighting factor ratio, and the first queue memory has a higher priority than the second queue memory. First and second queue memories for storing to have
It is determined whether or not the source address of the packet to be transmitted is the local station address, and when it is the local station address, the packet is inserted into the first queue memory and transmitted through the transmission buffer. And a control means for controlling to insert into the second queue memory and transmit via the transmission buffer when not .   5. The communication apparatus according to claim 4, further comprising means for inputting and setting the weighting coefficient ratio.   6. The communication apparatus according to claim 4, wherein the control means controls to read and transmit packets from the two queue memories using a weighted round robin method. A communication method for an ad hoc wireless network comprising a plurality of wireless stations and performing packet communication between the wireless stations ,
Provided in the preceding stage of the transmission buffer, receive packets to be transmitted, and receive packets having different priorities with a predetermined weighting factor ratio, and the first queue memory has a higher priority than the second queue memory. In the communication device including the first and second queue memories for storing to have
It is determined whether or not the source address of the packet to be transmitted is the local station address, and when it is the local station address, the packet is inserted into the first queue memory and transmitted through the transmission buffer. If not , the communication method includes a control step of controlling to insert into the second queue memory and transmit via the transmission buffer .   8. The communication method according to claim 7, further comprising the step of inputting and setting the weighting coefficient ratio.   9. The communication method according to claim 7, wherein the control step performs control so that packets are read from the two queue memories and transmitted using a weighted round robin method.

Images