JP4853862B2 - Communication device - Google Patents

Description

  The present invention relates to a communication apparatus, and more particularly to a communication apparatus that performs high-speed and high-performance communication.

  A standard network protocol is constructed based on a TCP (Transmission Control Protocol) / IP (Internet Protocol) layer type model.

  The TCP / IP layer type model includes a link / MAC (Media Access Control) layer, a network layer, a transport layer, and an application layer. In the TCP / IP layer type model, the link / MAC layer, the network layer, the transport layer, and the application layer play different roles.

  That is, the link / MAC layer establishes a path for physically connecting the two communication devices and performs communication between the two communication devices. The network layer performs route selection and route interruption on the network. The transport layer performs end-to-end communication processing, congestion processing, and the like. The application layer performs processing related to detailed operations of a specific application.

  Further, in the TCP / IP layer type model, a plurality of protocols belonging to the link / MAC layer, the network layer, the transport layer, and the application layer are structurally independent of each other and play the respective roles described above. Has characteristics. In other words, the protocol change in a specific layer is performed without affecting the protocol in other layers.

  A terminal device that performs communication in a wired network and a wireless device that performs wireless communication in a wireless network are configured by the above-described TCP / IP layer type model.

  The wireless network differs from the wired network in the following points.

  (1) The radio wave state greatly fluctuates due to reflection and blocking.

  (2) Each wireless device located in the same communication range communicates by sharing a wireless channel.

  (3) The wireless device is movable.

  As a result of the difference (1) between the wireless network and the wired network, the quality of communication is greatly different, for example, packet loss occurs due to multipath communication and temporary communication disconnection.

  In addition, since the wireless network has (2) different points from the wired network, fairness between wireless devices or flows during channel access becomes an important issue.

  Further, the wireless network has (3) different points from the wired network, and as a result, route disconnection, network disruption, and the like occur.

  Therefore, in the wireless network, the communication state dynamically changes. And it is difficult to specify the cause of this communication state fluctuation. As a result, when each of the plurality of protocols constituting the TCP / IP layer type model operates independently, the quality and efficiency of communication deteriorate.

  For these reasons, in order to perform high-efficiency and high-quality wireless communication in a wireless network, information is exchanged between a plurality of protocols constituting the TCP / IP layer model, and communication quality and Cross layer processing that improves efficiency is required.

  Therefore, conventionally, a cross-layer process called ECN (Explicit Connection Notification) for notifying TCP of a congestion state in the link layer is performed (Non-patent Document 1).

  In this cross-layer process, when packet loss occurs due to congestion in the relay terminal, the relay terminal sets the CE (Congestion Experienced) bit in the header of the packet that arrives next to the lost packet, and transfers the packet to the transmission destination. The transmission destination that has received the packet in which the CE bit is set sets the ECN-Echo bit in the header of the ACK (Acknowledge) packet and transmits the packet to the transmission source TCP.

The transmission source TCP that has received the ACK packet in which the ECN-Echo bit is set detects that the packet has been lost due to congestion by detecting the ECN-Echo bit from the ACK packet.
K. Ramakrishnan and S.M. Floyd, “A Proposal to add Explictation Notification (ECN) to IP”, RFC 2481, Jan 1999.

  In conventional cross-layer processing, specific different protocols directly exchange information, and thus have the following problems.

  The first problem is based on the premise that specific protocols for exchanging information are actually operating, and lacks diversity. As a second problem, a protocol that requires information needs to know where the corresponding information of the other protocol is stored, and the implementation lacks generality. As a third problem, when a plurality of protocols require equivalent information, redundant information exchange is performed, which is wasteful. As a fourth problem, when cross-layer processing increases, the overall management becomes difficult. As a fifth problem, there is a case where the protocol needs to be changed, and the originality of the protocol may be lost. The sixth problem is not suitable for optimization as a whole system for efficiently supporting QoS (Quality of Service) and security.

  Accordingly, the present invention has been made to solve such a problem, and an object of the present invention is to provide a communication device that can easily perform cross-layer processing while maintaining the uniqueness of a plurality of layers. .

  According to the present invention, the communication device includes a plurality of layers and a cross layer management unit. Each of the plurality of layers performs an independent operation independently, and communicates with other communication devices as a whole. In response to a request from the first layer, which is at least one of the plurality of layers, the cross-layer management unit includes a first layer other than the first layer of the first layer and the plurality of layers so as to satisfy the request. Cross layer processing is managed between two layers.

  Preferably, the communication device further includes an information transmission unit. The information transmission unit is added to each of the plurality of layers, and exchanges information between each of the plurality of layers and the cross layer management unit.

  Preferably, the cross layer management unit manages the exchange of information for cross layer processing between the first and second layers existing in the same communication apparatus.

  Preferably, the first layer receives predetermined information necessary to satisfy the request from the cross-layer management unit, and optimizes communication with other communication devices or a network state based on the received predetermined information. The control to make it.

  Preferably, the cross layer management unit exchanges information with other communication devices and manages the cross layer processing.

  Preferably, the cross layer management unit exchanges information using dedicated packets and manages the cross layer processing.

  Preferably, the cross layer management unit receives predetermined information necessary for satisfying the request from the cross layer management unit in another communication apparatus, and provides the received predetermined information to the first layer. The first layer performs control for optimizing the communication with other communication devices or the state of the network based on predetermined information received from the cross layer management unit.

  Since the communication device according to the present invention includes a cross layer management unit that manages cross layer processing between the first layer and the second layer in response to a request from the first layer, each of the plurality of layers The cross-layer processing is performed between the first and second layers without being aware of other layers. That is, the cross layer processing is performed between the first and second layers via the cross layer management unit while each of the plurality of layers independently executes its own operation.

  Therefore, according to the present invention, the cross layer process can be easily executed.

  Embodiments of the present invention will be described in detail with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals and description thereof will not be repeated.

  FIG. 1 is a schematic diagram showing a configuration of a communication apparatus according to an embodiment of the present invention. A communication device 10 according to an embodiment of the present invention includes layers 1 to 4, an information transmission unit 5, and a cross layer management unit 6.

  Layer 1 belongs to the link / MAC layer, and includes, for example, a FIFO (First-In First-Out) scheduler, an RR (Round Robin) scheduler, and a MAC protocol. The FIFO scheduler is a scheduling method that takes out the packets stored in the buffer in the order in which they were stored, the RR scheduler is a scheduler that evenly assigns transfer slots to each user, and the MAC protocol is, for example, MAC802.11b, 802.11g And the like, and performs processing for channel access, and performs transmission control and retransmission control of data (packets) between two communication apparatuses. Therefore, layer 1 performs packet buffering, scheduling processing, communication between two communication devices, and the like.

  Layer 2 belongs to the network layer, and includes, for example, RIP (Routing Information Protocol) protocol, OLSR (Optimized Link State Routing Protocol), ICMP (Internet Control Message Protocol Protocol), and ARP (Address Ressolation Protocol RP). Protocol) protocol.

  The RIP protocol is a protocol in which routers automatically transmit each other's routing information. OLSR is a table-driven routing protocol. The ICMP protocol is a protocol for transferring an IP error message and a control message.

  The ARP protocol is a protocol for obtaining a physical address based on a network address, and is mainly used for obtaining a MAC address from an IP address. The RARP protocol is a protocol for obtaining an IP address from a MAC address. Therefore, layer 2 performs route selection and route interruption on the network.

  Layer 3 belongs to the transport layer, and includes, for example, a TCP protocol and a UDP (User Datagram Protocol) protocol. Both the TCP protocol and the UDP protocol are transport protocols for performing data communication between a transmission source and a transmission destination. The TCP protocol retransmits a lost packet or performs congestion control when congestion occurs. Therefore, the TCP protocol is a protocol suitable for applications that require reliability. On the other hand, the UDP protocol is suitable for applications that require real-time performance because it does not perform processing such as congestion control and retransmission.

  The layer 4 belongs to an application layer, and includes, for example, an HTTP (Hyper Text Transfer Protocol) protocol, an FTP (File Transfer Protocol) protocol, a DNS (Domain Name System), and an SSL (Secure Socket Layer). The HTTP protocol is a protocol used by a web server and a client to transmit / receive data to / from each other. The FTP protocol is a protocol used for transferring a file. DNS is a system that searches the IP address of a terminal from the host name of each computer terminal on the Internet. SSL is a security function that encrypts and transmits information. Therefore, the layer 4 performs processing related to detailed operations of a specific application.

  As described above, each of the layers 1 to 4 includes at least one of a protocol for performing communication, a scheduler for scheduling such as buffering, and a mechanism for supporting communication, and independently performs its own operation.

  The information transmission part 5 consists of units 51-54. The units 51 to 54 are provided in addition to the layers 1 to 4, respectively. The unit 51 exchanges information between the layer 1 and the cross layer management unit 6. The unit 52 exchanges information between the layer 2 and the cross layer management unit 6. The unit 53 exchanges information between the layer 3 and the cross layer management unit 6. Unit 54 exchanges information between layer 4 and cross-layer management FIG.

  Accordingly, the information transmission unit 5 can respond to each of the layers 1 to 4 as a whole, and exchanges information between each of the layers 1 to 4 and the cross layer management unit 6.

  The cross layer management unit 6 exchanges information, requests, instructions, and the like with each of the layers 1 to 4 via the information transmission unit 5 and performs cross layer processing within the communication device and between the communication devices as described later. Is provided to each of the layers 1 to 4.

  In this invention, in order to optimize communication between communication devices, the cross layer management unit 6 performs cross layer processing in response to a request received from any one of layers 1 to 4 via the information transmission unit 5. To manage the exchange of information necessary for this. And in this invention, the cross layer process in a communication apparatus or the cross layer process between communication apparatuses is performed. Hereinafter, cross-layer processing within the communication device and cross-layer processing between the communication devices will be described.

[Cross-layer processing in communication devices]
(A) Processing for Notifying TCP Protocol Every Time Route Status is Updated As a first example of cross-layer processing in the communication apparatus, processing for notifying the TCP protocol every time the route status is updated will be described.

  FIG. 2 is a diagram for explaining a first example of cross-layer processing in the communication apparatus. FIG. 3 is a schematic diagram of the wireless network system. FIG. 4 is a diagram illustrating an example of a routing table.

  FIG. 2 shows a cross-layer process between the TCP protocol belonging to layer 3 and the routing protocol belonging to layer 2 shown in FIG. In this case, in the communication device 10 illustrated in FIG. 1, the layer 2 includes, for example, an OLSR (Optimized Link State Routing) protocol that is a table-driven routing protocol. Further, communication devices M1 to M13 having the same configuration as that of the communication device 10 constitute the radio network system 100 shown in FIG. 3, and in each of the communication devices M1 to M13, the routing protocol (= OLSR protocol) is set up to the transmission destination. Holds a routing table consisting of For example, the communication device M1 holds a routing table RT1 shown in FIG.

  The routing table RT1 includes a transmission destination, the next communication device, and the number of hops. The transmission destination, the next communication device, and the number of hops are associated with each other. “Destination” represents the IP address of the destination communication device. “Next communication device” represents an IP address of a communication device to be transmitted next when a packet is transmitted to a transmission destination. “Hop number” represents the number of hops to the destination.

  Accordingly, the routing protocol (= OLSR protocol) of the communication device M1 holds a routing table RT1 composed of 12 routes whose destinations are the communication devices M2 to M13.

  In the wireless network system 100, each of the communication devices M1 to M13 creates a routing table by the following method. The communication devices M1 to M13 transmit and receive a Hello message and a TC message when creating a routing table.

  The Hello message is periodically transmitted for the purpose of distributing information included in each of the communication devices M1 to M13. By receiving this Hello message, each of the communication devices M1 to M13 can collect information on peripheral communication devices, and recognizes what communication devices exist around the communication device.

  In the OLSR protocol, each of the communication devices M1 to M13 manages local link information. The Hello message is a message for constructing and transmitting the local link information. The local link information includes “link set”, “adjacent communication device set”, “two-hop adjacent communication device set and link set to those communication devices”, “MPR (Multipoint Relay) set”, and “MPR selector set”. including.

  A link set is a link to a set of communication devices (adjacent communication devices) through which radio waves directly reach, and each link is expressed by an effective time of a set of addresses between two communication devices. The valid time is also used to indicate whether the link is unidirectional or bidirectional.

  The adjacent communication device set is configured by an address of each adjacent communication device, a retransmitting degree (Willingness) of the communication device, and the like. The 2-hop adjacent communication device set represents a set of communication devices adjacent to the adjacent communication device.

  The MPR set is a set of communication devices selected as MPR. Note that MPR means that when each packet is transmitted to all the communication devices M1 to M13 of the wireless network system 100, each communication device M1 to M13 transmits and receives one packet only once, thereby transmitting the packet to all communication devices. The relay communication device is selected so that it can be transmitted to M1 to M13.

  The MPR selector set represents a set of communication devices that have selected themselves as MPRs.

  The process of establishing local link information is generally as follows. In the initial stage of the Hello message, each communication device M11 to M13 transmits a Hello message containing its own address to an adjacent communication device in order to notify its own existence. All of the communication devices M1 to M13 perform this, and each of the communication devices M1 to M13 grasps what address a communication device has around itself. In this way, a link set and an adjacent communication device set are constructed.

  The constructed local link information is continuously sent again by a Hello message again. By repeating this, it is gradually clarified whether each link is bidirectional or what kind of communication device exists ahead of the adjacent communication device. Each of the communication devices M1 to M13 stores the local link information that is gradually constructed in this way.

  Further, information regarding MPR is also periodically transmitted by a Hello message and notified to each of the communication devices M1 to M13. Each of the communication devices M1 to M13 selects several communication devices as neighboring MPRs as MPR sets as communication devices that request retransmission of packets transmitted by the communication devices M1 to M13. Then, since the information regarding the MPR set is transmitted to the adjacent communication device by the Hello message, the communication device that has received the Hello message uses the set of communication devices that the MPR has selected as the MPR as the “MPR selector set”. to manage. By doing in this way, each communication apparatus M1-M13 can recognize immediately from which communication apparatus the packet received should be retransmitted.

  When a local link set is established in each of the communication devices M1 to M13 by transmitting and receiving a Hello message, a TC message for informing the topology of the entire wireless network system 100 is transmitted to the communication devices M1 to M13. This TC message is periodically transmitted by all the communication devices selected as the MPR. Since the TC message includes a link between each communication device and the MPR selector set, all the communication devices M1 to M13 of the wireless network system 100 know all the MPR sets and all the MPR selector sets. Based on all the MPR sets and all the MPR selector sets, the topology of the entire wireless network system 100 can be known. Each of the communication devices M1 to M13 calculates the shortest path using the topology of the entire wireless network system 100, and creates a route table based on the calculated shortest path.

  Each of the communication devices M1 to M13 frequently exchanges TC messages separately from Hello messages. MPR is also used for exchanging TC messages.

  Layer 3 of each of the communication devices M1 to M13 transmits and receives the above-described Hello message and TC message, recognizes the topology of the entire radio network system 100 based on the received Hello message and TC message, and the entire radio network system 100 Based on the topology, the shortest path is calculated, and a routing table is dynamically created based on the shortest path.

  The communication device M1 creates the routing table RT1 (see FIG. 4A) by the method described above, selects a route from the created routing table RT1, and performs wireless communication with each destination.

  When the communication device M1 performs wireless communication with each transmission destination, the TCP protocol belonging to the layer 3 of the communication device M1 notifies the information every time the route state corresponding to the specific transmission / reception address is updated. The process is requested to the cross layer management unit 6 via the information transmission unit 5 (step S1). That is, the TCP protocol belonging to layer 3 outputs a request DEM 1 to the cross layer management unit 6 via the information transmission unit 5.

  When the cross layer management unit 6 receives the request DEM1 via the information transmission unit 5, the cross layer management unit 6 confirms the presence of information regarding the corresponding route information and requests information provision (step S2). More specifically, the cross layer management unit 6 examines the content of the request DEM 1 and outputs the request DEM 2 for requesting route information to the routing protocol belonging to the layer 2 via the information transmission unit 5.

  When the routing protocol belonging to layer 2 receives the request DEM2 from the cross-layer management unit 6, the requested information is present in the routing table RT1, so that the provision of route information is permitted (step S3). That is, the routing protocol belonging to layer 2 outputs permission OK1 to the cross layer management unit 6 via the information transmission unit 5 in response to the request DEM2.

  Upon receiving permission OK1 from the routing protocol belonging to layer 2, the cross layer management unit 6 outputs permission OK2 for the request DEM1 to the TCP protocol belonging to layer 3 via the information transmission unit 5 (step S4).

  Thereafter, when the route between the communication device M1 and the communication device M7 is disconnected, the routing table RT1 is updated to the routing table RT2 (see FIG. 4B). When the route between the communication device M1 and the communication device M7 is disconnected, the route having the communication device M7 as a transmission destination and the route having the communication device M7 as the next communication device are updated.

  That is, the route having the communication device M7 as the transmission destination is deleted, and the next communication device is changed in the route having the communication device M7 as the next communication device (see the box in FIG. 4B). In FIG. 4B, in order to indicate that the route having the communication device M7 as the transmission destination has been deleted, the portion in which the route having the communication device M7 as the transmission destination is stored is left blank. .

    When the routing table RT1 is updated to the routing table RT2, the routing protocol belonging to layer 2 outputs the updated routing table RT2 to the cross layer management unit 6 via the information transmission unit 5. That is, the routing protocol belonging to layer 2 notifies the cross layer management unit 6 of the route state (step S5).

  When the cross layer management unit 6 receives the routing table RT2 from the routing protocol belonging to layer 2, the cross layer management unit 6 detects that the route between the communication device M1 and the communication device M7 is disconnected, and between the communication device M1 and the communication device M7. Information about route disconnection is notified to the TCP protocol belonging to layer 3 via the information transmission unit 5 (step S6).

  When the TCP protocol belonging to layer 3 receives information from the cross-layer management unit 6 that the route between the communication device M1 and the communication device M7 is disconnected, the TCP protocol optimizes communication with other communication devices based on the received information. .

  More specifically, the TCP protocol belonging to layer 3 determines whether or not the route is disconnected (step S7). In this case, when the TCP protocol belonging to the layer 3 receives the route disconnection information from the cross layer management unit 6, it determines “YES” in step S 7 and receives the route disconnection information from the cross layer management unit 6. If not, “NO” is determined in step S7.

  When it is determined that the route is not disconnected, the TCP protocol belonging to layer 3 continues or resumes TCP communication (step S8). On the other hand, when it is determined that the route is disconnected, the TCP protocol belonging to layer 3 temporarily stops communication while retaining parameters such as a congestion window size and a retransmission timer (step S9). As a result, information that the route has been disconnected is transmitted from the routing protocol belonging to layer 2 to the TCP protocol belonging to layer 3, and communication is optimized in the TCP protocol belonging to layer 3.

  Thus, the cross-layer management unit 6 responds to the request DEM1 to notify the TCP protocol every time the route status from the TCP protocol belonging to the layer 3 is updated, and the TCP belonging to the layer 3 and the routing protocol belonging to the layer 3. Manages the exchange of information with the protocol, and the TCP protocol belonging to the layer 3 optimizes the communication in the communication device M1 using the route disconnection information received from the routing protocol belonging to the layer 2 via the cross-layer management unit 6 Turn into.

  In this case, the layers involved in the cross-layer processing shown in FIG. 2 are layers 2 and 3 among layers 1 to 4, and the cross-layer management unit 6 ensures unique operations of each layer 1 to 4. In addition, since the exchange of information between layers 2 and 3 is managed, cross-layer processing between the routing protocol belonging to layer 2 and the TCP protocol belonging to layer 3 can be easily performed.

  In FIG. 2, Steps S1 to S4 constitute an information exchange start work, and Steps S5 to S9 constitute an information exchange work. Accordingly, the cross-layer process includes an information exchange start work and an information exchange work.

(B) Processing for Informing Packet Transmission Rate Information to Routing Protocol As a second example of cross-layer processing in the communication apparatus, processing for informing the routing protocol of packet transmission rate information will be described.

  FIG. 5 is a diagram for explaining a second example of the cross-layer processing in the communication apparatus. FIG. 6 is a diagram illustrating another example of the routing table. FIG. 5 shows a cross-layer process between the routing protocol belonging to layer 2 and the MAC protocol belonging to layer 1 shown in FIG.

  The communication device M6 holds a routing table RT3 whose destination is each of the communication devices M1 to M5 and M7 to M13 (see FIG. 6A). And the communication apparatus M6 is communicating with each transmission destination using the routing table RT3.

  In such a situation, cross-layer information exchange starts with the following work. The routing protocol belonging to layer 2 of the communication device M6 is configured to notify the cross-layer management unit 6 via the information transmission unit 5 of processing for informing information about the information transmission rate to the neighboring terminal A (= communication device M9) every 60 seconds. A request is made (step S11). That is, the routing protocol belonging to the layer 2 outputs the request DEM 3 to the cross layer management unit 6 via the information transmission unit 5.

  The cross-layer management unit 6 examines the content of the request DEM3 in response to the request DEM3 from the routing protocol belonging to layer 2, and detects that the total number of successfully transmitted and failed packets is requested. Then, the cross-layer management unit 6 sends a request DEM4 that informs the total number of packets successfully transmitted to the terminal A (= communication device M9) and the number of packets unsuccessfully transmitted via the information transmission unit 5 every 60 seconds. To the MAC protocol belonging to layer 1 (step S12). Further, the cross layer management unit 6 outputs permission OK3 for the request DEM3 to the routing protocol belonging to the layer 2 via the information transmission unit 5 (step S13). Thereby, the information exchange start work is completed.

  Thereafter, when the information exchange operation is started, the MAC protocol belonging to layer 1 receives a notification indicating that 60 seconds have passed from a built-in timer (not shown), and in response to the received notification, the terminal A The number of successful transmission packets and the number of unsuccessful transmission packets up to (= communication device M9) are provided to the cross layer management unit 6 via the information transmission unit 5 (step S14).

  Then, based on the number of successful transmission packets and the number of unsuccessful transmission packets received from the MAC protocol belonging to layer 1, the cross layer management unit 6 calculates (number of successful transmission packets) / (number of successful transmission packets + number of unsuccessful transmission packets). The packet transmission rate is calculated to calculate (step S15).

  Then, the cross layer management unit 6 notifies the calculated packet transmission rate to the routing protocol belonging to the layer 2 via the information transmission unit 5 (step S16). When the routing protocol belonging to layer 2 receives the packet transmission rate from the cross layer management unit 6, it updates the routing table RT3 using the received packet transmission rate as follows.

  The routing protocol belonging to layer 2 determines whether or not the packet transmission rate is lower than the threshold (step S17). When the packet transmission rate is lower than the threshold, the communication device M9 is set as the next communication device (NextHop). The route is recalculated (step S18).

  More specifically, the routing table RT3 includes a route whose destination is the communication device M10 and a route whose destination is the communication device M12 as a route where the terminal A (= communication device M9) is the next communication device. (Excluding a route whose destination is the communication device M9). Therefore, the routing protocol belonging to layer 2 updates the route [transmission destination: communication device M10, next communication device: communication device M9] to the route [transmission destination: communication device M10, next communication device: communication device M8]. , The route [transmission destination: communication device M12, next communication device: communication device M9] is updated to the route [transmission destination: communication device M12, next communication device: communication device M11]. That is, the routing protocol belonging to layer 2 updates the routing table RT3 to the routing table RT4 (see FIG. 6B).

  As a result, the communication device M6 can communicate with the communication devices M10 and M12 while maintaining the packet transmission rate at or above the threshold.

Note that when it is determined in step S17 that the packet transmission rate is equal to or greater than the threshold value, the routing table RT3 is maintained.
In this way, the routing protocol belonging to layer 2 optimizes communication with other communication devices (communication devices M10 and M12) based on the packet transmission rate.
In addition, the cross layer management unit 6 performs information processing for converting a plurality of information received from the layer 1 into new information suitable for cross layer control.

  As described above, the cross layer management unit 6 determines whether the MAC protocol belonging to the layer 1 and the routing protocol belonging to the layer 2 are in response to the request DEM3 that informs the information on the information transmission rate from the routing protocol belonging to the layer 2. The routing protocol belonging to the layer 2 optimizes the communication in the communication device M6 using the route disconnection information received from the MAC protocol belonging to the layer 1 via the cross layer management unit 6.

  In this case, the layers involved in the cross-layer processing shown in FIG. 5 are layers 1 and 2 out of layers 1 to 4, and the cross-layer management unit 6 ensures unique operations of the layers 1 to 4 In addition, since the exchange of information between layers 1 and 2 is managed, cross-layer processing between the MAC protocol belonging to layer 1 and the routing protocol belonging to layer 2 can be easily performed.

  Note that the cross-layer processing in the communication device is not limited to the above-described cross-layer processing, and may be the following cross-layer processing.

(I) Cross-layer processing CLPR1 that uses information of a MAC layer belonging to layer 1 (for example, received signal strength of a packet) by a routing protocol belonging to layer 2
(Ii) Cross-layer processing CLPR2 in which the packet loss information of the application layer belonging to layer 4 is used by the routing protocol belonging to layer 2
(Iii) Cross-layer processing CLPR3 in which the information of the network layer belonging to layer 2 is used by the application layer belonging to layer 4 to change the packet transmission method
When the cross-layer processing CLPR1 is performed, in each communication device, the MAC layer belonging to layer 1 detects the received signal strength of the packet, and the detected received signal strength is passed through the information transmission unit 5 to the cross-layer management unit 6. The cross layer management unit 6 passes the received signal strength received from the MAC layer belonging to layer 1 to the routing protocol belonging to layer 2 via the information transmission unit 5.

  Then, the routing protocol belonging to layer 2 determines a route to each destination based on the received signal strength received from the cross layer management unit 6. That is, the routing protocol belonging to Layer 2 selects a route having a relatively strong received signal strength and establishes a route to each destination. More specifically, the routing protocol belonging to layer 2 establishes a route to the transmission destination by selecting a route having a relatively strong received signal strength even when the number of hops increases.

  When the cross layer processing CLPR2 is performed, in each communication device, the application layer belonging to layer 4 notifies the packet loss information to the cross layer management unit 6 via the information transmission unit 5, and the cross layer management unit 6 Then, the packet loss information received from the application layer belonging to the layer 4 is passed to the routing protocol belonging to the layer 2 via the information transmission unit 5.

  Then, the routing protocol belonging to layer 2 determines a route to each transmission destination based on the packet loss information received from the cross layer management unit 6. That is, the routing protocol belonging to layer 2 selects a route with relatively little packet loss and establishes a route to each destination. More specifically, the routing protocol belonging to layer 2 establishes a route to the transmission destination by selecting a route with relatively little packet loss even when the number of hops increases.

  Further, when cross-layer processing CLPR3 is performed, in each communication device, the network layer belonging to layer 2 notifies the cross-layer management unit 6 of an IP error message via the information transmission unit 5, and the cross-layer management unit 6 Passes an IP error message received from the network layer belonging to the layer 2 to the application layer belonging to the layer 4 via the information transmission unit 5.

  Then, the application layer belonging to the layer 4 changes the transmission method from TCP transmission to UDP transmission based on the IP error message received from the cross layer management unit 6.

  As described above, in the present invention, the cross-layer processing in the communication device includes various types of cross-layer processing.

[Cross-layer processing between communication devices]
FIG. 7 is a configuration diagram of a dedicated packet used in cross-layer processing between communication devices. The dedicated packet PKTC includes a MAC header, an IP header, a cross layer header, and a data part.

  The MAC header is a normal MAC header. The IP header includes a Protocol field. In the Protocol field, “cross layer” is stored as an upper protocol.

  The cross layer header includes src_id and an event. src_id represents the communication device that created the dedicated packet PKTC. The event stores the cause of the necessity of performing the cross layer process. The data portion stores detailed instructions or information for cross-layer processing.

  When cross-layer processing between communication devices is performed, the cross-layer management unit 6 of the communication device exchanges information using the dedicated packet PKTC. Then, the cross layer management unit 6 of the communication apparatus transmits the dedicated packet PKTC by any one of unicast, multicast, and flooding.

  Hereinafter, cross layer processing between communication apparatuses using the dedicated packet PKTC will be described.

(C) Processing for Transmitting Information from Link Layer of Relay Terminal to TCP Layer of Source Terminal FIG. 8 is a conceptual diagram for explaining a first example of cross layer processing between communication devices. FIG. 9 is a flowchart for explaining a first example of cross-layer processing between communication devices. In FIG. 8, communication device A is a transmission source terminal, and communication device B is a relay terminal.

  The transport layer belonging to layer 3 of communication apparatus A, which is the transmission source terminal, transmits the data packet to communication apparatus B via the network layer belonging to layer 2 and layer 1.

  Layer 1 of communication device B, which is a relay terminal, receives the data packet from communication device A and outputs the received data packet to the network layer belonging to layer 2. Then, the network layer belonging to layer 2 of communication device B outputs the data packet from communication device A to layer 1 for relaying to the transmission destination. However, if a buffer overflow (congestion) occurs in layer 1 of the communication apparatus B, the data packet is discarded (step S21).

  Thus, when a packet loss occurs in layer 1 of communication device B, layer 1 of communication device B notifies cross layer management unit 6 that the packet has been lost via information transmission unit 5 (step S22). ).

  When receiving the packet loss from layer 1, the cross layer management unit 6 of the communication device B sets Protocol = cross layer in the Protocol field, sets the IP address of the communication device B in src_id, and transmits the TCP to the receiving terminal. And a dedicated packet PKTC in which the TCP packet loss is stored in the event is created (step S23).

  When creating the dedicated packet PKTC, the cross layer management unit 6 transmits the created dedicated packet PKTC to the communication apparatus A via the information transmission unit 5, the network layer belonging to layer 2, and layer 1 (step S24).

  The layer 1 of the communication device A receives the dedicated packet PKTC from the communication device B, and passes the received dedicated packet PKTC to the cross layer management unit 6 via the information transmission unit 5 (step S25).

  Then, the cross layer management unit 6 of the communication device A analyzes the dedicated packet PKTC received from the layer 1 and indicates that the packet loss has occurred due to buffer overflow (congestion) in the communication device B (relay terminal). The corresponding TCP belonging to layer 3 is notified via (step S26).

  When the corresponding TCP belonging to layer 3 receives a notification from the cross layer management unit 6 that indicates that packet loss has occurred due to buffer overflow (congestion) in the communication device B (relay terminal), it performs congestion control (step S27). . Thereby, the cross layer process between the communication apparatus A and the communication apparatus B is completed.

Thus, the cross layer management unit 6 of the communication device A and the cross layer management unit 6 of the communication device B exchange information between the transport layer belonging to layer 3 of the communication device A and layer 1 of the communication device B. To manage cross-layer processing. As a result, the transport layer belonging to layer 3 of the communication device A can easily know that a packet loss due to congestion has occurred in the communication device B, and quickly performs congestion control as a countermeasure against the packet loss due to the congestion. be able to.
(D) Multiple Cross Layer Processing FIG. 10 is a conceptual diagram for explaining a problem that occurs in a network. The communication devices A to F constitute a network, the communication device B exists in the communication region REG1 of the communication device A, and the communication devices C and D communicate within the communication region REG1 of the communication device A and the communication device E. The communication device E exists in the region REG2, the communication device E exists outside the communication region REG1 of the communication device A, the communication device F exists in the communication region REG3 of the communication device B, and is outside the communication region REG1 of the communication device A. Exists.

  Then, the communication device A transmits the traffic 1 to the communication device E via the communication device C because the communication device E exists outside the own communication region REG1, and the communication device F present in the own communication region REG1. Trying to send traffic 2 to Traffic 1 is composed of a packet for executing an application called Video Streaming, and traffic 2 is composed of a packet for executing an application called WEB browsing.

  In such a situation, the problem 1 that the packet collision frequently occurs in the communication region REG1 of the communication apparatus A occurs, and the problem 2 that the communication apparatus B and the communication apparatus C are in a congested state occurs.

  FIG. 11 is a flowchart for explaining detection of problem 1 shown in FIG. The occurrence of a packet collision in the communication area REG1 of the communication device A is performed in the communication device A. The MAC protocol belonging to layer 1 of the communication device A receives a notification every 60 seconds from the built-in timer, and detects the number of packet collisions and the number of successful packet transmissions in 60 seconds. Then, the MAC protocol belonging to layer 1 notifies the cross layer management unit 6 of the detected number of collisions and the number of successful packet transmissions via the information transmission unit 5 (step S31).

  When receiving the number of collisions and the number of successful packet transmissions from the MAC protocol belonging to layer 1, the cross layer management unit 6 calculates the number of collisions / (the number of successful packet transmissions + the number of collisions) to obtain the packet collision rate (step S32). ).

  Then, the cross layer management unit 6 determines whether or not the obtained packet collision rate is larger than the threshold (step S33). When the packet collision rate is larger than the threshold, “the channel is crowded, It is detected that it is necessary to reduce the load applied to the channel (step S34). Thereby, the cross layer management unit 6 of the communication apparatus A detects the problem 1.

  In step S33, when the packet collision rate is equal to or less than the threshold value, the cross layer management unit 6 of the communication apparatus A detects that the packet collision does not become a problem.

  FIG. 12 is a conceptual diagram for explaining detection of problem 2 shown in FIG. FIG. 13 is a flowchart for explaining the detection of the problem 2 shown in FIG. The layer 1 of the communication device B or C detects the occurrence of congestion by detecting that the queue size has exceeded the threshold (step S41).

  The layer 1 of the communication device B or C notifies the detected congestion occurrence to the cross layer management unit 6 via the information transmission unit 5 (step S42). Upon receiving congestion from Layer 1, the cross layer management unit 6 sets Protocol = cross layer in the Protocol field, sets the IP address of the communication device B or C in src_id, and sets the communication device A in the receiving terminal. Then, a dedicated packet PKTC in which the occurrence of congestion is stored in the event is created (step S43).

  When creating the dedicated packet PKTC, the cross layer management unit 6 transmits the created dedicated packet PKTC to the communication device A via the information transmission unit 5, the network layer belonging to layer 2, and layer 1 (step S44).

  Then, the layer 1 of the communication apparatus A receives the dedicated packet PKTC, and passes the received dedicated packet PKTC to the cross layer management unit 6 via the information transmission unit 5 (step S45). Then, the cross layer management unit 6 of the communication device A analyzes the dedicated packet PKTC and detects that congestion has occurred in the communication device B or the communication device C (step S46). Further, the cross layer management unit 6 of the communication device A determines that “it is necessary to use a route that avoids a communication device in a congested state or to reduce a transfer rate transmitted to those communication devices” (step S47). Thereby, the detection of the problem 2 is completed.

  Thus, the problem 2 is detected by the cross layer process between the communication apparatuses.

  FIG. 14 is a conceptual diagram of a layer that supports two traffics. As layer 4, application 1 = Video and application 2 = WB browsing are executed.

  Application 1 (= Video) communicates with other communication devices via UDP, routing protocol, and MAC protocol. Application 2 (= WEB browsing) communicates with other communication devices via TCP, routing protocol, and MAC protocol.

  FIG. 15 is a flowchart for explaining an operation for solving problems 1 and 2 shown in FIG. When the cross layer management unit 6 of the communication device A detects that the communication device C is congested, the cross layer management unit 6 searches for a route for accessing the communication device E without going through the communication device C as a countermeasure 1. An instruction is given to the routing protocol belonging to layer 2 via the information transmission unit 5 (step S51).

  Then, the routing protocol belonging to layer 2 establishes a route to the communication device E having the communication device D as the next communication device (step S52). Thus, communication with the communication device E can be performed while avoiding the communication device C in a congested state.

  Further, when the cross layer management unit 6 of the communication device A detects that the communication device B or C is in a congested state, the countermeasure 2 is that the TCP belonging to the layer 3 reduces the window size and decreases the transfer rate. An instruction is given to the protocol via the information transmission unit 5 (step S53).

  Then, the TCP protocol belonging to layer 3 decreases the window size and decreases the transfer rate (step S54). Thereby, the congestion in the communication apparatus B or C can be reduced.

  Furthermore, the cross layer management unit 6 of the communication apparatus A gives an instruction to the application 1 belonging to the layer 4 through the information transmission unit 5 so as to use a method with a higher compression rate (step S55).

  Then, the application 1 belonging to the layer 4 uses a compression method with a higher compression rate and reduces the data amount (step S56). Thereby, the load given to the channel can be reduced.

  Further, the cross layer management unit 6 of the communication apparatus A instructs the application 2 belonging to the layer 4 via the information transmission unit 5 so as to reduce the number of colors used for images on the WEB page. (Step S57).

  Then, the application 2 belonging to the layer 4 reduces the number of colors used for the image and the like, and reduces the data amount (step S58). Thereby, the load given to the channel can be reduced, and the congestion information of the communication apparatus B can be reduced.

  As described above, when the MAC protocol belonging to layer 1 of the communication device A detects the number of collisions and the number of successful packet transmissions and notifies the cross layer management unit 6 (see step S31), the cross layer management unit 6 of the communication device A Calculates a packet collision rate based on the number of collisions and the number of successful packet transmissions to detect packet collisions in the communication area REG1 of the communication device A (see steps S32 and S33). Then, an instruction is given to reduce the window size and reduce the transfer rate (see step S53), and the TCP protocol belonging to layer 3 performs communication by reducing the window size and the transfer rate (see step S54). ). Accordingly, in the communication apparatus A, cross-layer processing between the MAC protocol belonging to layer 1 and the TCP protocol belonging to layer 3 is performed.

  When layer 1 of communication device B or C detects the occurrence of congestion and notifies cross layer management unit 6 of communication device A (see steps S41 to S45), cross layer management unit 6 of communication device A performs communication. It is detected that the device B or C is in a congested state (see step S46), and an instruction Com1 is given to the routing protocol belonging to the layer 2 so as to search for a route for accessing the communication device E while avoiding the communication device C (step S46). (See S51), an instruction Com2 is given to the application 1 belonging to the layer 4 so as to use a compression method having a higher compression rate (see step S55), and the layer 4 is reduced so as to reduce the number of colors used in the image or the like. An instruction Com3 is given to the application 2 to which it belongs (see step S57), and the routing protocol belonging to layer 2 In response to the instruction Com1, a route for accessing the communication apparatus E avoiding the communication apparatus C is established (see step S52), and the application 1 belonging to the layer 4 can compress the instruction Com2 with a higher compression rate. Is used to reduce the data amount (see step S56), and the application 2 belonging to the layer 4 reduces the number of colors and the data amount for the instruction Com3 (see step S58). Accordingly, cross-layer processing is performed between the protocol 1 (link layer) of the communication device B or C and the applications 1 and 2 belonging to the layer 4 of the communication device A.

  Thereby, Problem 1 and Problem 2 shown in FIG. 1 are solved.

  Note that the cross-layer processing between communication devices is not limited to the above-described cross-layer processing, and may be the following cross-layer processing.

(Iv) Cross-layer processing CLPR4 in which information of protocol 1 (MAC layer) of the communication partner (for example, signal strength to the communication partner of itself) is used by the routing protocol belonging to its own layer 2
When the cross-layer processing CLPR4 is performed, the MAC layer belonging to layer 1 of the communication apparatus A that is the communication partner detects the received signal strength of the packet, and the detected received signal strength is cross-layered via the information transmission unit 5. The cross-layer management unit 6 of the communication apparatus A generates a dedicated packet PKTC that stores the received signal strength received from the MAC layer belonging to the layer 1 and notifies the management unit 6 to the information transmission unit 5, the network layer, and the link layer. Is transmitted to the communication apparatus B.

  The layer 1 of the communication device B receives the dedicated packet PKTC from the communication device A, and outputs the received dedicated packet PKTC to the cross layer management unit 6 via the information transmission unit 5. The cross layer processing unit 6 of the communication device B analyzes the dedicated packet PKTC and detects the received signal strength transmitted from the communication device A from the dedicated packet PKTC. Then, the cross layer management unit 6 of the communication apparatus B passes the detected received signal strength to the routing protocol belonging to the layer 2 via the information transmission unit 5.

  Then, the routing protocol belonging to layer 2 of the communication apparatus B determines a route to each transmission destination based on the received signal strength received from the cross layer management unit 6. That is, the routing protocol belonging to layer 2 of the communication device B selects a route having a relatively strong received signal strength and establishes a route to each destination. More specifically, the routing protocol belonging to layer 2 of the communication device B selects a route with relatively high received signal strength even when the number of hops increases, and establishes a route to the transmission destination.

  As described above, in the present invention, the cross-layer processing between communication devices includes various cross-layer processing.

  According to this invention, since the communication device 10 includes the cross layer management unit 6 that manages the exchange of information for cross layer processing between the plurality of layers 1 to 4, each of the plurality of layers 1 to 4 Necessary information is acquired via the cross layer management unit 6. That is, the cross layer processing is performed between the plurality of layers via the cross layer management unit 6 while each of the plurality of layers independently performs its own operation. Therefore, according to the present invention, the cross layer process can be easily executed.

  In the present invention, cross-layer processing is performed on one or more different layers based on information exchange between layers, optimization of information from one or more layers, and information from one or more layers. It consists of instructing QoS (Quality of Service) and operations for the purpose of security.

  In the above, it has been described that the communication device 10 constitutes the wireless network system 100. However, in the present invention, the communication device 10 may constitute a wired network system. Is used as a communication device that supports cross-layer processing within and between terminal devices in all TCP / IP networks.

  For example, the communication device 10 is used as a communication device that supports cross-layer processing within an access point of a mesh wireless network or cross-layer processing between access points. The communication device 10 is used as a communication device that supports cross-layer processing in an ad hoc network.

  The information transmission unit 5 and the cross layer management unit 6 described above are realized by software. And the information transmission part 5 draws out the request | requirement and information, etc. from each of the layers 1-4, and outputs it to the cross layer management part 6, and sucks out the data, information, etc. from the cross layer management part 6, Give to 4. That is, the information transmission unit 5 functions to smoothly exchange information between each of the layers 1 to 4 and the cross layer management unit 6.

  As described above, since the information transmission unit 5 and the cross layer management unit 6 are added to the layers 1 to 4 in the communication device 10 by software, the unique operations performed independently by each of the layers 1 to 4 are guaranteed. The functions of the information transmission unit 5 and the cross layer management unit 6 can be easily implemented in the communication device 10 as they are.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is shown not by the above description of the embodiments but by the scope of claims for patent, and is intended to include meanings equivalent to the scope of claims for patent and all modifications within the scope.

  The present invention is applied to a communication apparatus that can easily execute cross-layer processing while maintaining the uniqueness of a plurality of layers.

It is the schematic which shows the structure of the communication apparatus by embodiment of this invention. It is a figure for demonstrating the 1st example of the cross layer process in a communication apparatus. 1 is a schematic diagram of a wireless network system. It is a figure which shows the example of a routing table. It is a figure for demonstrating the 2nd example of the cross layer process in a communication apparatus. It is a figure which shows the other example of a routing table. It is a block diagram of the exclusive packet used in the cross layer process between communication apparatuses. It is a conceptual diagram for demonstrating the 1st example of the cross layer process between communication apparatuses. It is a flowchart for demonstrating the 1st example of the cross layer process between communication apparatuses. It is a conceptual diagram for demonstrating the problem which generate | occur | produces in a network. It is a flowchart for demonstrating the detection of the problem 1 shown in FIG. It is a conceptual diagram for demonstrating the detection of the problem 2 shown in FIG. It is a flowchart for demonstrating the detection of the problem 2 shown in FIG. It is a conceptual diagram of the layer which supports two traffics. It is a flowchart for demonstrating the operation | movement which solves the problems 1 and 2 shown in FIG.

Explanation of symbols

  1-4 layers, 5 information transmission units, 6 cross-layer management units, 10, M1-M13 communication devices, 51-54 units, 100 wireless network systems.

Claims (6)

A plurality of layers that each independently perform its own operation and communicate with other communication devices as a whole,
In response to a request from a first layer that is at least one of the plurality of layers, a second of the first layer and the plurality of layers other than the first layer so as to satisfy the request A cross-layer management unit that manages cross-layer processing with other layers ,
An information transmission unit that is added to each of the plurality of layers and exchanges information between each of the plurality of layers and the cross-layer management unit ;
The cross-layer processing includes information exchange between layers, optimization of information from one or more layers, and QoS and security for one or more different layers based on information from one or more layers. A communication device comprising instructing an operation for the purpose . The cross-layer management section manages the exchange of information for the cross-layer processing between the first and second layers are in the same communication device, the communication device according to claim 1. The first layer receives predetermined information necessary for satisfying the request from the cross layer management unit, and based on the received predetermined information, communicates with the other communication device or a network state. The communication apparatus according to claim 2 , wherein control for optimization is performed. The communication device according to claim 1 , wherein the cross layer management unit exchanges information with the other communication device to manage the cross layer processing. The communication device according to claim 4 , wherein the cross layer management unit exchanges the information using a dedicated packet and manages the cross layer processing. The cross layer management unit receives predetermined information necessary to satisfy the request from the cross layer management unit in the other communication device, and gives the received predetermined information to the first layer,
Said first layer, on the basis of the predetermined information received from the cross-layer managing unit performs control for optimizing the state of the communication or the network with the other communication apparatus, according to claim 4, wherein Item 6. The communication device according to Item 5 .

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