CN100448222C - Channel assignment method in special peer-to-peer network - Google Patents

Abstract

The present invention relates to a method for channel assignment in special peer-to-peer networks (Ad Hoc Networks), which uses reservation requirements (RREQ), reservation responses (RRSP), code assignment (CASN), Code Conflict Detection (CCD), Code Conflict Report (CCR), and Code Confirmation (CCFM) six-stage retention procedures and inter-cluster RTS-CTS dialogue protocol to establish Time Division Multiple Access (TDMA) Time slots and designated codes can be used to support real-time communication in multi-step special peer-to-peer networks and provide QoS guarantees.

Description

Channel assignment method in special peer-to-peer network

technical field

The invention relates to the technical field of a special peer-to-peer network, in particular to a channel assignment method suitable for supporting real-time traffic in a special peer-to-peer network.

Background technique

In recent years, wireless networks (Wireless networks) have developed vigorously, and one of the fastest growing ones is Mobile Ad Hoc Networks (Mobile Ad Hoc Networks). Compared with other networks (such as mobile phone networks or satellite networks), the biggest feature of special peer-to-peer networks is that they do not have a fixed infrastructure. Such networks only contain mobile nodes. In the case of a limited transmission range of each node, all nodes can help their adjacent nodes to relay (relay) data, so the network is formed by communication between mobile nodes, and the network extension Pau (Topology) will change dynamically as some mobile nodes join or leave. Therefore, the special peer-to-peer network has considerable flexibility and robustness, and it can be applied to harsh environments where fixed infrastructure cannot be used, such as in For battlefields or areas damaged by natural disasters such as earthquakes, special peer-to-peer networks can be quickly deployed to provide the required communication services.

In the aforementioned special peer-to-peer network, the effective communication distance between a mobile node and another mobile node is called a hop, and due to the limitation of the effective communication distance of each mobile node, when the distance is greater than the When two nodes at a communication distance want to establish a connection for communication, they must rely on the relay of other mobile nodes to relay data, thus forming a multi-hop environment. Compared with a wireless network with infrastructure (such as a mobile phone network), the communication requirements of all mobile stations can be known through the base station, and bandwidth reservation can be easily realized. In such networks, for the acquisition and configuration of channels, there is no centralized control to coordinate the allocation of resources, so the scheduling (scheduling) is complicated. In addition, the wireless communication platform is an open space, and it is possible at any time Therefore, it is not easy to achieve the guarantee of quality of service (QoS) by establishing a connection in a multi-hop network and reserving bandwidth to support real-time traffic (Real-Time Traffic). In the peer-to-peer network, distributed computing must be used to realize the required control functions, and the network structure into a hierarchical organization becomes a problem to be solved by distributed computing. and other networks have been widely used. As shown in FIG. 1, each cluster 11 (cluster) is generally composed of a plurality of mobile nodes 12 that are geographically close to each other, and the mobile nodes 12 in the same cluster 11 can communicate with each other. , and one of the two adjacent clusters 11 has at least one gateway node 12 capable of communicating with the other cluster 11 .

The wireless channel shared between the mobile nodes 12 of the above-mentioned special peer-to-peer network adopts TDMA (Time Division Multiple Access) and CDMA (Code Division Multiple Access) to allocate bandwidth, that is, a channel essentially includes a time slot (Time slot) and a code (Code), when a link (link) is established, the transmitting node 121 and the receiving node 123 use the same code to communicate in a configured time slot, that is, to transmit and receive packets. One of the major challenges of this special peer-to-peer network is how to properly allocate channels among the clusters 11 to ensure that data can be successfully transmitted without collisions, and at the same time increase the channel reuse rate to improve system performance.

In order to configure a channel between mobile nodes 12, it is necessary to select a pair of codes for the mobile node 12. If the number of available codes is more than the number of mobile nodes 12, each mobile node 12 can be assigned a Specific encoding, in this case, there are two ways of communication: one is RCA (Receiver-based code assignment), that is, the transmitting end communicates with it according to the encoding of the receiving end; the other is TCA (Transmitter-based code assignment ), the receiving end uses the encoding of the transmitting end to receive data. However, in a general ad hoc network, since the number of available codes is less than the number of mobile nodes 12, how to efficiently reuse codes becomes an extremely important issue.

Also, in a special peer-to-peer network, as shown in FIG. 1, there may be two nodes 121 and 122 that are out of the communication range from each other and transmit packets to the same other node 123 at the same time, causing a frontal collision (Head collision) at the node 123. -on collision), or because node 121 transmits a packet to node 124, and node 122 transmits a packet to node 123, causing a side collision (Side-way collision) at node 123, thus causing the so-called hidden terminal (hidden terminal) problem , but must be resolved during system design.

Contents of the invention

An object of the present invention is to provide a channel assignment method to support real-time transmission in an ad hoc peer-to-peer network.

Another object of the present invention is to provide a channel assignment method, which can ensure no coding conflicts and hidden endpoints, completely avoid any interference, and achieve better coding efficiency.

In order to achieve the above object, the present invention proposes a channel assignment method in a special peer-to-peer network, wherein the special peer-to-peer network has a plurality of mobile nodes, which are formed into several clusters, and a control node is defined in each cluster node , the control node is one step away from any node in the same slave set, and a common code is defined in each cluster, so that all nodes in the cluster can use the common code to encode and send packets. This method It includes: a step of assigning channels within a cluster and a step of reserving bandwidth between clusters. The steps of channel assignment in the cluster include: a reservation request (RREQ) stage, in which a RREQ packet is sent by a desired transmission node to reserve information time slots; a reservation response (RRSP) stage, in which a receiving node reports receipt of the RREQ Packet; A code assigns (CASN) stage, selects a specified code from its coding table by the control node that detects the transmission of the RRSP packet to assign to these intended transmission nodes and receiving nodes; A code conflict detection (CCD) stage, It is to send a greeting message (hello) to the receiving node by using the specified code to transmit a node that has been assigned the specified code or the node that is already transmitting, so as to test the possible collision of the specified code assignment conflict; a code conflict report (CCR ) stage is to report the collision of the possible designated code assignment conflict by the receiving node; and a code confirmation (CCFM) stage is to report a confirmation message to its control node to establish by the transmission node that does not have a collision among the receiving nodes. For the reserved channel, if a CCR packet is received, the control node releases the previously assigned designation code back into the coding table. The steps of reserving the bandwidth between the clusters include: -request to transmit (RTS) stage, which is sent by a desired transmission node with a common code of a receiving node -RTS information is given to the receiving nodes of adjacent clusters; and a start transmission (CTS) ) stage, when the receiving node receives the unique RTS information, the receiving node sends out -CTS information with its common code in response to inform that the RTS has been received successfully, and the reserved bandwidth is established.

Description of drawings

FIG. 1 shows a known cluster-ad hoc peer-to-peer network.

FIG. 2 shows the system architecture implementing the channel assignment method in the special peer-to-peer network of the present invention.

FIG. 3 shows a frame structure defined by timing according to the method of the present invention.

FIG. 4 shows the flow of channel assignment in a regional sub-control slot according to the method of the present invention.

FIG. 5 shows the process of performing bandwidth reservation in adjacent clusters in a global sub-control slot according to the method of the present invention.

FIG. 6 shows an example of a specific peer-to-peer network implementing the channel assignment method of the present invention.

FIG. 7 shows an example of an ad hoc peer-to-peer network implementing the channel assignment method of the present invention.

Figure 8 shows an example of the operation of the six phases of the special peer-to-peer network in a regional sub-control slot according to the present invention

Figure 9 shows various possible schemes of the control node's RREQ with respect to two intra-cluster links according to the invention.

FIG. 10 shows various conditions of channel establishment by the method of the present invention when there is inter-cluster link interference of adjacent clusters.

Detailed ways

Regarding the channel assignment method in the special peer-to-peer network of the present invention, please refer to the system architecture diagram implementing the method of the present invention shown in Figure 2 first, wherein, all mobile nodes 20 (Mobile Node, MN) of the special peer-to-peer network form There are several clusters 21 (clusters), and the nodes 20 of each cluster 21 can be divided into three roles: control node (Cluster-head), gateway node (Gateway node) and general node. Each cluster 21 will have a control node 22, and this control node 22 is only one step away from any node 20 in the same cluster 21, that is, in a cluster 21, any node 20 and other nodes 20 at most Two steps apart (two-hop). A common code (common code) is defined in each cluster 21 again, so that all nodes 20 in the cluster 21 can use the common code to encode and transmit packets to other nodes 20 in the same cluster 21, and The common codes of adjacent clusters are different to avoid mutual interference with each other. In two adjacent clusters 211 and 212, one of the clusters 211 has at least one gateway node 203 that can communicate with the node 20 of the other cluster 212 (that is, the gateway node 203 is one step away from at least one node 20 of the adjacent cluster 212 Procedure). In addition, the mobile nodes 20 in the special peer-to-peer network transmit in half-duplex mode, that is, any mobile node 20 can only transmit packets or receive packets at the same time.

In the aforementioned special peer-to-peer network, packets are sent and received between nodes 20 through a dynamically established wireless channel, which is defined by a time slot (Time slot) and a code (Code), and the time slot is controlled by A time slot (control slot, CS) and an information time slot (information slot, IFS) are formed, and the aforementioned time slot is defined in a sequence, so that all nodes 20 follow this sequence for sending and receiving. FIG. 3 shows that according to the aforementioned sequence The defined frame structure (frame structure), which is formed by the continuation of control time slot (CS) and information time slot (IFS), wherein, in the control time slot, the node 20 can send and receive control packets, and in the information time slot Among them, the node 20 can send and receive data packets, as shown in Figure 3, the control time slot further includes a plurality of global sub-control time slots G(i), i=1..M (for clusters 21) and multiple areas Secondary control time slot L(j), j=1..N (used in cluster 21), each global secondary control time slot G includes a request to send (Request To Send, RTS) and a start to send (Clear To Send , CTS) phase (phase), and each regional sub-control time slot L includes Reservation Request (Reservation Request, RREQ), Reservation Response (Reservation Response, RRSP), Code Assignment (Code Assignment, CASN), Code Conflict Detection (Code Conflict Detection) Conflict Detection (CCD), code conflict report (Code Conflict Report, CCR), and code confirmation (Code Conform, CCFM) and other six stages.

Fig. 4 shows the process flow of the distributed algorithm channel assignment method in the special peer-to-peer network of the present invention, and please refer to the system architecture diagram shown in Fig. 2, when a mobile node 20 intends to establish a link (link) to transmit data, as The established link belongs to the same cluster 21, then carry out an intra-cluster procedure to use the regional control time slot L to compete and establish a channel by the winner, and then use the information time slot (IFS) to transmit data; If the established links do not belong to the same cluster 21, an inter-cluster procedure is performed to compete using the global secondary control time slot G and the winner establishes a channel, which is then transmitted in an information time slot (IFS) data. Fig. 5 shows the process that a node 201 that wants to transmit in the cluster 21 performs channel assignment in an area sub-control time slot L by the procedure in the aforementioned cluster. First, in the RREQ stage, the node 201 that wants to transmit sends a RREQ packet Time slot for retaining information. In detail, the intended transmitting node 201 will transmit a RREQ packet to a receiving node 202 with its common code encoding, while other nodes 20 that do not transmit receive the RREQ packet with the common code encoding, and they may not receive the RREQ packet , or a neighboring node receives one RREQ packet, or more than one RREQ packet, if more than one RREQ packet is received, a collision occurs and all RREQ packets are invalid.

Secondly, in the RRSP stage, the receiving node 202 reports the receipt of the RREQ packet in the previous stage. That is, if the receiving node 202 receives a single RREQ packet with its common code, then the receiving node 202 sends an RRSP packet with its common code encoding to indicate that it has successfully received the RREQ packet, and the control node in the cluster 21 22 also receives the RRSP packet with its common code, so the transmission node 201 can determine whether the RREQ packet it transmits is successful according to whether it receives the RRSP packet at this stage, if the transmission node 201 does not receive the RRSP packet, then Indicates that the transmission of the RREQ packet failed.

In the CASN phase, the control node 22 that detected the transmission of the RRSP packet in the previous phase will assign a specific code to the node pair that has successfully completed the RREQ and RRSP phases. Specifically, if the control node 22 has previously received at least one RRSP packet or sent an RRSP packet, the control node 22 selects an appropriate specified code, such as _C1 , from the code table 213 to which its cluster 211 belongs. , and broadcast the assignment information of the designated code _C1 with its common code, and the node 201 to be transmitted and the receiving node 202 will receive the designated code with their common code.

In the CCD phase, the transmission node 201 that has been assigned the specified code in the previous stage uses this specified code to send a greeting message (hello) to the receiving node 202, and the receiving node 202 needs to receive the packet with this specified code, so as to To test possible conflicts of assigned codes, other nodes that do not have any tasks are idle and do not act. In detail, the desired transmission node 201 sends a greeting message (hello) with the specified code _C1 , and any node within the transmission distance and using the specified code _C1 for communication can also receive the greeting message, and at the same time, in the network The sender of any established link in 202 will also send a greeting message with the specified code C _X used by it, and the receiving node 202 may receive one or more than one greeting message, wherein, more than one greeting message is received Indicates a collision of assigned codes, which means that at least one node pair belonging to an adjacent cluster is also assigned the same assigned code, which is equivalent to a collision of hidden endpoints between clusters.

In the CCR stage, the receiving node 202 reports the collisions that occurred in the previous stage. That is, if the receiving node 202 receives two or more greeting messages (hello) with the specified code C ₁ , then the receiving node 202 sends a collision message (collision) with the specified code C ₁ , and the desired transmitting node 201 can pass Whether the collision information is received at this stage is known whether the specified code encounters a conflict between clusters.

In the CCFM stage, the transmission node 201 that has no collision in the previous stage reports a confirmation message to its control node 22 to establish a reserved channel. That is, if the transmission node 201 does not receive the collision information (collision), then the transmission node 201 transmits an acknowledgment message (ack) with its common code encoding, and the control node 22 receives the acknowledgment message with its common code, and can Determine that this specified code C ₁ has been successfully assigned to the intended transmission node 201 and receiving node 202, and release this specified code from the coding table, so the transmitting node 201 and the receiving node 202 will be able to use this specified code in the information time slot (IFS) Designate code _C1 to transmit and receive data packets without causing interference to other links.

Fig. 6 shows the process that node 202 performs bandwidth reservation in adjacent clusters 211 and 212 in a global secondary control time slot G. First, in the RTS phase, as the desired transmission node 203 of cluster 211 (it is a gateway node or a control node ) to transmit a packet to the receiving node 204 of the adjacent cluster 212, the desired transmitting node 203 will send an RTS message to the receiving node 204 with the common code of the receiving node 204 in the next global sub-control time slot, and the remaining data has not been received The nodes 20 of the nodes receive the packets with the common codes of the respective clusters they belong to.

If the transmitting node of another cluster or the transmitting node of the same cluster also transmits the RTS information in this global sub-control time slot, a collision occurs at the receiving node 204 and causes transmission failure, and the desired transmitting node 203 will send the RTS information at the next opportunity Contest again, for example, resend an RTS message in the next global control time slot.

In the CTS stage, if the receiving node 204 receives the unique RTS, it will send a CTS message with its common code to respond to the successful receipt of the RTS, and the node 203 to be transmitted that has sent the RTS message will receive the packet with the common code of the receiving node 204 , and when receiving the CTS information, confirm the establishment of the reserved bandwidth, and transmit data with the common code of the receiving node.

Figure 7 shows an example of a special peer-to-peer network implementing the channel assignment method of the present invention, which includes four clusters 61-64, cluster 61 includes nodes N1, N2 and N3 (N3 is a gateway node), and cluster 62 includes node N4 and N5, cluster 63 includes nodes N6, N7, and N8 (N6 is a gateway node), cluster 64 includes nodes N9, N10, and N11 (N9 is a gateway node), and clusters 61 to 64 share CC ₁ to CC ₄ respectively Code, the nodes N2, N4, N7 and N10 are the control nodes of the clusters 61-64 respectively.

Figure 8 shows the operation example of the aforementioned special peer-to-peer network in the six stages of RREQ, RRSP, CASN, CCD, CCR, and CCFM in the sub-control time slot L of a region. First, in the RREQ stage, the node N1 is coded with the common code CC ₁ Send the RREQ packet to node N2, node N3 encodes the common code CC ₁ to send the RREQ packet to node N2, node N5 encodes the common code CC ₂ to send the RREQ packet to node N4, node N6 encodes the common code CC ₃ to send the RREQ packet to the node N7, node N10 transmits RREQ packet to node N11 with common code CC ₄ encoding, node N9 transmits RREQ packet to node N10 with common code CC ₄ encoding (because node N10 also transmits RREQ packet, under half-duplex mode, it does not receive RREQ packet transmitted by N9), it can be known that nodes N2, N4, N7 and N11 are receiving nodes.

In the RRSP stage, since the receiving node N2 received two RRSP packets, it was judged to be invalid, while the other receiving nodes N4, N7 and N11 all received the only RREQ packet, so the node N4 transmitted an RRSP packet with the common code CC ₂ , which is received by node N5 which is one step away; node N7 transmits an RRSP packet encoded with common code CC ₃ , and is received by nodes N6 and N8 which are one step apart; node N11 transmits an RRSP packet encoded with common code CC ₄ , and is received by the node N10 which is one step away.

In the CASN stage, the control node N4 that previously sent an RRSP packet finds out a specified code C ₁ in its coding table 621, and sends the information of the specified code C ₁ with the common code CC ₂ , and the distance between Received by node N5 of one trip. The control node N7 that previously sent an RRSP packet finds out a specific code C ₁ , and encodes the specific code C ₁ with the common code CC ₃ and transmits it, which is then received by the nodes N6 and N8 one step apart. The control node N10 that previously received an RRSP packet finds a specific code C ₂ , and sends the specific code C ₂ with the common code CC ₄ to be received by the nodes N9 and N11 one step apart.

In the CCD stage, the node N5 to transmit sends a hello message (hello) with the specified code _C1 , and the node N4 within one step receives the hello message with the specified code _C1 . The transmitting node N6 sends a hello message with the assigned code _C1 , and the hello message is received by the nodes N4 and N7 within one step. The node N10 to transmit sends a hello message with the specified code _C2 , and the node N11 within one step receives the hello message, and the other nodes without any tasks are all idle and do not act.

In the CCR stage, since the receiving node N4 receives two greeting messages (hello) with the specified code _C1 , the receiving node N4 sends a collision message (collision) with the specified code _C1 to the nodes N5 and N6 which are one step apart, wherein Nodes N5 and N6 determine a communicable node through a collision analysis program, for example, node N6 is selected according to the rules that control nodes have priority over normal nodes, or nodes that have previously established links have priority over nodes that send collision information.

In the CCFM stage, because the node N6 to be transmitted can be regarded as not receiving the collision information (collision) due to the selection of the priority, the node N6 to transmit is coded with the common code CC ₃ to transmit an acknowledgment message (ack), and the control node If received by N7, the control node N7 confirms that the specified code C ₁ does not conflict, and assigns the specified code C ₁ to the node N6 to be transmitted and the node N7 to receive the packet for packet transmission. In addition, the node N10 to transmit has not received the collision information (collision), so the node N10 to transmit transmits an acknowledgment message encoded with the common code _CC4 , and is received by the nodes N9 and N11, because the node N10 to transmit is itself a control node , so it confirms that the specified code _C2 does not conflict, and assigns the specified code _C2 to the node N10 to be transmitted and the node N11 to receive the packet for packet transmission.

The aforementioned method of the present invention can ensure that co-channel interference (co-channel interference) or hidden terminal (hidden terminal) problems will not occur within a cluster or between clusters. To illustrate this effect, FIG. 9 shows that the control node H is related to Various possible schemes of RREQ linked in two clusters, for each scheme, the behavior of the control node is shown in the first three phases (RREQ, RRSP, CASN), where, in Figure 9(A), in the RREQ phase, node N1 and N3 both send RREQ packets to node N2, so control node H receives two RREQ packets; in the RRSP stage, because node N2 receives two RREQ packets and collides, so control node H does not receive any RRSP packets; therefore, in In the CASN stage, there will be no action.

In Fig. 9(B), in the RREQ phase, the control node H sends the RREQ packet to the node N1 (the node N2 also sends the RREQ packet to the node N1); in the RRSP phase, because the node N1 receives two RREQ packets and collides, the control node H does not receive any RRSP packet; therefore, there will be no action during the CASN phase.

In Fig. 9(C), in the RREQ stage, nodes N1 and N2 both send RREQ packets to the control node H, so the control node H receives two RREQ packets; in the RRSP stage, the control node H receives two RREQ packets and collides , so the control node H will not send any RRSP packets; therefore, there will be no action during the CASN stage.

In Fig. 9(D), in the RREQ stage, node N1 sends RREQ packets to node N3 and node N2 sends RREQ packets to control node H, so control node H receives two RREQ packets; in RRSP stage, because control node H receives Two RREQ packets collide, so the control node H will not send any RRSP packets, but the node N1 will send an RRSP packet and be received by the control node H; therefore, in the CASN stage, the control node H will assign a specific code to the node N1 and Links between nodes N3.

In Figure 9(E), in the RREQ phase, the control node H sends a RREQ packet to the node N1 (the node N3 also sends a RREQ packet to the node N2); in the RRSP phase, the node N2 receives two RREQ packets and collides, and the control node H only The RRSP packet transmitted by the node N1 is received; therefore, in the CASN stage, the control node H assigns a specific code to the link between the control node H and the node N1.

In Fig. 9(F), in the RREQ stage, node N1 sends a RREQ packet to node N4 and node N3 sends a RREQ packet to node N2, so the control node H receives two RREQ packets; in the RRSP stage, node N2 receives two RREQ packets When the packets collide, the control node H only receives the RRSP packet sent by the node N4; therefore, in the CASN stage, the control node H will assign a specific code to the link between the node N1 and the node N4.

In Fig. 9(G), in the RREQ stage, the control node H sends the RREQ packet to the node N2 (the node N1 also sends the RREQ packet to the control node H); in the RRSP stage, the control node H only receives the packet sent by the node N2 RRSP packet; therefore, in the CASN stage, the control node H will assign a specific code to the link between the control node H and the node N2.

In Fig. 9(H), in the RREQ stage, node N2 sends a RREQ packet to node N1 and node N3 sends a RREQ packet to node N2, so the control node H receives two RREQ packets; in the RRSP stage, the control node H only receives The RRSP packet sent by the node N1; therefore, in the CASN phase, the control node H will assign a specific code to the link between the node N1 and the node N2.

In Fig. 9 (I), in the RREQ stage, node N2 sends RREQ packet to node N1 and node N4 sends RREQ packet to node N3, so control node H receives two RREQ packets; in RRSP stage, control node H receives RRSP packets transmitted by nodes N3 and N2; therefore, in the CASN stage, the control node H assigns specific codes to the link between node N1 and node N2 and the link between node N3 and node N4. This case mainly shows that two links are in the same cluster, but they will not interfere with each other, and the effect of coexistence can also be achieved by using this channel assignment method.

It can be seen from the above-mentioned Figures 9(A)-(I) that the first three stages of the method of the present invention can eliminate collisions caused by link interference within the cluster, and after eliminating the collisions caused by link interference within the cluster, it is necessary to further avoid Collisions caused by inter-cluster link interference, Figure 10 shows the various conditions of channel establishment when there is intra-cluster link interference of adjacent clusters, Figure 10(A) shows the links between nodes N1-N2 of two adjacent clusters I and J There is an interference with the N3-N4 link. When the two links are established at the same time, a collision is detected in the CCD stage. In the CCR stage, it is determined that the node N3-N4 link is successful, and the assignment to the node N3-N4 link can be confirmed in the CCFM stage. In the case that the two links are not established at the same time, if the node N1-N2 link is established earlier, the collision is detected in the CCD stage, and the node N4 receives the collision information in the CCR stage, so that the node N3-N4 link fails (But the node N1-N2 link still exists), and there will be no action in the CCFM stage. Another example is that the node N3-N4 link is established earlier, the collision is detected in the CCD stage, and the node N1 receives the collision information in the CCR stage. The node N1-N2 link fails (but the node N3-N4 link still exists), and there will be no action during the CCFM stage.

Figure 10(B) shows two adjacent clusters I and J, the node N1-N2 link and the N4-N3 link produce two interferences. In the case that the two links are established at the same time, the collision is detected in the CCD stage, and the node is determined in the CCR stage Both the N1-N2 link and the node N3-N4 link fail, and there will be no action in the CCFM stage; and in the case that the two links are not established at the same time, if the node N1-N2 link is established earlier, it will be detected by the CCD stage Collision, when nodes N1 and N4 receive collision information in the CCR stage, the node N3-N4 link fails (but the node N1-N2 link still exists), and there will be no action in the CCFM stage. It is established early, and the collision is detected in the CCD stage. In the CCR stage, the nodes N1 and N4 receive the collision information and the node N1-N2 link fails (but the node N3-N4 link still exists), and there will be no action in the CCFM stage.

It can be seen from the above-mentioned Fig. 10 (A) and (B) that when the same designated code is used in the intra-cluster link of the adjacent cluster and interferes, the method of the present invention can eliminate the relevant code in the last three stages (CCD, CCR, CCFM). The specified code of the problem, so that the channel can be established without collision.

As can be seen from the above description, the channel assignment method of the present invention establishes time division multiple access (TDMA) by using the six-stage reservation procedure in the cluster (intra-cluster) and the RTS-CTS dialogue protocol in the cluster (inter-cluster). ) time slots and selected designated codes, which can realize the purpose of supporting real-time transmission in a multi-step special peer-to-peer network. Among them, the first three stages of the six-stage reservation procedure can solve the collision in the cluster, and the last three stages are used to solve Collisions caused by the selection of designated codes between clusters can ensure that conflicts of designated codes and problems of hidden endpoints will not occur, completely avoid any interference, and provide QoS guarantees. Moreover, since the distributed algorithm channel assignment method of the present invention uses the designated codes dynamically, better usage efficiency of the designated codes can be achieved.

The above-mentioned embodiments are only examples for convenience of description, and the scope of rights claimed by the present invention should be determined by the scope of the claims, rather than limited to the above-mentioned embodiments.

Claims (12)

1. decentralized algorithm channel assigning method in special peer-to-peer network, wherein, this special peer-to-peer network has a plurality of mobile nodes, it forms some gathering together, definition has a Control Node in each node of gathering together, arbitrary node in this Control Node and same the gathering together is all at a distance of a step journey, come the sending and receiving package by a radio channel between the node, this passage is defined by a time slot and a coding, this time slot is formed by control time slot and information time slot, in the control time slot, node transmitting-receiving control package is competed with transceive data package in the information time slot, in each definition of gathering together make code is altogether arranged again, so that all nodes in this is gathered together are all with this common yard sending and receiving package of encoding, in adjacent two gather together, wherein one gather together have at least one can with the gateway node of another node communication of gathering together, be that gateway node and adjacent at least one node of gathering together are at a distance of a step journey, and the adjacent defined common sign indicating number of gathering together is inequality, when a mobile node tendency to develop transmission of data to same mobile node of gathering together, this method is carried out the following internal program of gathering together:

In one beachhead demand RREQ stage, send a RREQ package to keep the information time slot by the defeated node of a tendency to develop;

One keeps the response RRSP stage, keep response RRSP in the stage in this, receive unique RREQ package as a receiving node with its common sign indicating number, then this receiving node is sent out a RRSP package with its common sign indicating number coding, the RREQ package is received in i.e. this receiving node repayment, and the Control Node in it is gathered together also receives this RRSP package with its common sign indicating number;

One code assignment CASN stage was to assign a designated code to give the defeated node of this tendency to develop and this receiving node by the Control Node of the transmission that detects the RRSP package;

Generation code conflicts detects the CCD stage, is to use this designated code to transmit a greeting information by the defeated node of this tendency to develop that is assigned designated code to give this receiving node, assign the collision of conflict to test possible designated code;

The generation code conflicts repayment CCR stage is to repay the collision that this possible designated code is assigned conflict by receiving node; And

One code is confirmed the CCFM stage, is to repay a confirmation by the defeated node of the tendency to develop of not generation collision to give the passage of the Control Node in it is gathered together to confirm that designated code is errorless and foundation keeps;

Wherein, when the mobile nodes that a mobile node tendency to develop transmission of data is gathered together to difference, this method is carried out a following program of gathering together:

One requires to transmit the RTS stage, is to send a RTS information to an adjacent receiving node of gathering together by the defeated node of a tendency to develop, and wherein, this RTS information transmits with the common sign indicating number of this receiving node; And

Transmit the CTS stage at the beginning, when this receiving node is received unique RTS information, send a CTS information by this receiving node with its common sign indicating number and inform that with response success receives RTS information, and set up the frequency range that keeps.

2. the method for claim 1, wherein in this beachhead demand RREQ in the stage, the defeated node of this tendency to develop transmits RREQ package with its common sign indicating number coding and gives a receiving node.

3. method as claimed in claim 2, wherein, in this beachhead demand RREQ stage, other node that does not transmit receives package with the common sign indicating number coding of gathering together under it.

4. the method for claim 1, wherein, in this code assignment CASN in the stage, before received at least one RRSP package or sent out a RRSP package as Control Node, then find out a designated code the coding schedule of this Control Node under it is gathered together, and the assignment information of this designated code sent out with its common sign indicating number coding, and defeated node of this tendency to develop and receiving node will receive this designated code with its common sign indicating number.

5. the method for claim 1, wherein, in stage, the defeated node of tendency to develop is sent a greeting information with this designated code, and any transmitting terminal of having set up link in network also can be sent a greeting information with the employed designated code of this transmitting terminal in this code collision detection CCD.

6. method as claimed in claim 5, wherein, in the code collision detection CCD stage, all the other are failure to actuate for idle without any the node of task.

7. the method for claim 1, wherein repay CCR in the stage in this code conflict, if this receiving node is received plural greeting information with designated code, then this receiving node is sent a collision information with designated code.

8. method as claimed in claim 7 wherein, in the stage, is received plural greeting information if set up the node of link earlier with designated code in this code conflict repayment CCR, and then this node of setting up link is earlier sent a collision information with designated code.

9. method as claimed in claim 8, wherein, in this code conflict repayment CCR stage, the node that bumps be determine via a collision analysis program one can communication node.

10. method as claimed in claim 9, wherein, this collision analysis program has precedence over the rule of the node except that Control Node and gateway node and selects node according to Control Node.

11. the method for claim 1, wherein, confirm that in this code CCFM is in the stage, if the defeated node of this tendency to develop is not received collision information, then the defeated node of this tendency to develop transmits a confirmation with its common sign indicating number coding, this Control Node is received this confirmation with its common sign indicating number, carries out the package transmission and confirm this designated code is assigned between the defeated node of this tendency to develop and this receiving node, and this designated code is discharged from coding schedule.

12. the method for claim 1, wherein require to transmit RTS in the stage in this, all the other nodes that do not transmit data receive package with the common sign indicating number of gathering together under separately.

Images