CN101102540A - Multiple Access Method Supporting Quality of Service - Google Patents

Abstract

The invention relates to a multiple access method supporting quality of service, comprising: a node judges the service type according to the service group to be sent, if it is a real-time service, the node sends a forecast burst declaring the service type, and performs the next step; if it is not For real-time services, the node listens to a mini-slot with a predicted burst length. If it does not detect a predicted burst that declares the real-time service type, go to the next step; the node determines the start micro-slot for sending the predicted burst and sends the predicted burst The number of groups, the node listens to whether the channel is idle before the start of the mini-slot, if yes, the node sends one or more forecast bursts, and then judges whether the channel is idle, if yes, the node accesses the channel and sends a service packet . This method absorbs the ideas of burst reservation and conflict resolution, greatly reduces the influence of hidden terminals in packet transmission, and ensures the quality of service.

Description

Multiple Access Method Supporting Quality of Service

technical field

The invention relates to a multiple access method supporting quality of service, in particular to a multiple access method supporting quality of service relying on declarations to differentiate service types.

Background technique

Multiple access is a method to solve how multiple nodes or users share channel resources quickly, efficiently, fairly and reliably. According to channel allocation methods, multiple access methods can generally be divided into three types: fixed allocation, random access, and on-demand allocation.

The fixed-allocation multiple access method generally allocates channel resources to some nodes or all nodes that share the channel for a long time. Since there are a large number of mobile nodes in various mobile communication networks, and the business of each node is mostly bursty business, the multiple access method of fixed allocation will cause a lot of channel resources to be idle and waste, which is not suitable for mobile communication networks. Direct application in mobile communication network.

In the multiple access method of random access, each node usually competes to use the channel after a random delay according to the carrier sense situation. Although this method can overcome the resource waste problem in the fixed allocation access method, and can obtain a small access delay when the traffic volume is small, each node shares the wireless broadcast channel in a multi-hop network structure based on carrier sensing. When , there will be problems of hidden terminals and exposed terminals, which will greatly reduce the performance of multiple access. Especially when the number of sending nodes and network traffic increase, the probability of packet collision and retransmission will increase sharply, thus greatly increasing the average packet delay and average packet discarding rate, reducing the channel throughput, and at the same time Issues such as unfair sharing of channels occur.

In the multiple access method of on-demand allocation, each node applies for channel resources according to business conditions, and uses the channel resources after the application is successful. According to the different ways of applying for reservation and allocating channels, the method can be divided into two types based on random contention and based on non-conflict. The method based on random competition mainly adopts various short control group handshakes (such as sending request/clear request, Request To Send/Clear To Send, hereinafter referred to as RTS/CTS), periodic state information exchange and other distributed reservation methods, which are suitable for sudden Highly explosive and short-transmission business transmission, such as IEEE 802.11 protocol distributed coordination function (Distributed Coordination Function, referred to as DCF), dual busy tone multiple access (Dual Busy Tone Multiple Access, referred to as DBTMA) and distributed grouping Reservation multiple access (Dynamic Packet Reservation Multiple Access, referred to as DPRMA) and other methods. The non-conflict-based method mainly uses the central control node to coordinate to achieve on-demand allocation, which is suitable for business types that require a long period of stable transmission after an access is established, and can provide a good quality of service (QoS for short). ) guarantee, and its typical representatives mostly use polling mechanisms, such as Point Coordination Function (PCF for short) and Virtual Base Station (Virtual Base Station, VBS for short) of the IEEE 802.11 protocol. However, the former still has packet collisions in the application reservation part, and the influence of hidden terminals is only weakened, but not eliminated; the latter can avoid the occurrence of packet collisions, but when many nodes do not send, this method will waste Lots of polling control overhead.

At the same time, there are other problems in the on-demand allocation multiple access method proposed in the prior art. For example, when the network traffic is low, compared with the random access method, the on-demand allocation method has an excessive proportion of control overhead. When the network traffic is high, compared with the fixed allocation method, the on-demand allocation method has problems such as the maximum channel throughput is not high enough, and the fairness of the shared channel cannot be guaranteed. In addition, among the various multiple access methods mentioned above, there are many multiple access methods that can only be realized under the premise of establishing relatively accurate network synchronization. accurate synchronization.

At present, multiple access protocols also consider the support of QoS for multimedia services, and their implementation methods can generally be divided into two categories: one is based on service differentiation protocols, that is, priority allocation and fair scheduling for different services, such as IEEE 802.11 The Enhanced Distributed Coordination Function (EDCF for short) of e-protocol adopts differentiated frame interval (Inter Frame space, IFS for short) and back-off algorithm for four access types, and supports eight different service priorities; The other is a protocol based on resource reservation, which mainly provides QoS services for real-time services through reservation and scheduling mechanisms. There are still many research works based on the IEEE 802.11 standard Carrier Sense Multiple Access with Collision Detection (CSMA/CA for short) based on the idea of real-time service priority, docking The entry mechanism is improved by dividing business priority and using different back-off strategies, so as to realize QoS support on the existing network. However, when the CSMA/CA-based access mechanism is applied to a multi-hop network, it is difficult to ensure that the delay of all high-priority services is limited to a small range, because the transmission of low-priority services that are being alternately carried out in adjacent nodes may It hinders the start of high-priority services, and the RTS/CTS handshake without start time limit also restricts the QoS performance of real-time services in multi-hop networks.

Contents of the invention

One aspect of the present invention is to provide a multiple access method that supports quality of service. This method can support QoS without a central control node. The two types of services are first differentiated by declarations, and then reserve channels and conflicts with short burst competition. The solution mechanism ensures that real-time service packets can quickly access the channel to the greatest extent, obtain the right to use the channel, and complete transmission prior to general non-real-time service packets.

One aspect of the present invention provides the following technical solution through some embodiments. The technical solution specifically provides a multiple access method supporting quality of service, including:

Step 1, the node judges the service type according to the service grouping to be sent, if it is a real-time service, the node then sends a forecast burst (Forecast Burst, hereinafter referred to as FB) packet declaring the service type, and performs step 2; if it is a non-real-time service , the node listens to a mini-slot of the FB packet length, if no FB packet declaring the real-time service type is heard, then step 2 is performed;

Step 2, the node determines the starting mini-slot for sending FB packets and the number of sending FB packets, whether the node listens to the channel before the mini-slots before the starting mini-slot, if yes, then Execute step 3; otherwise, return to step 1;

Step 3, the node sends one or more FB packets to determine whether the channel is in an idle state, if yes, then perform step 4; otherwise, return to step 1;

Step 4. The node accesses the channel and sends a service packet.

In the multiple access method supporting quality of service provided by the embodiment of the present invention, nodes send FB packets in the competition stage to perform competition and conflict resolution technical solutions, which ensures that real-time service packets can access channels more preferentially, and greatly reduces the Possible packet collisions during transmission.

In summary, the embodiment of the multiple access method supporting quality of service in the present invention absorbs the ideas of burst reservation and conflict resolution, greatly reduces the influence of hidden terminals in packet transmission, and enables flexible and simple burst prediction and conflict resolution The method can enable the nodes to access the channel faster and more effectively, and can guarantee the conflict-free transmission of real-time service packets to the greatest extent. The embodiment of the multi-access method supporting quality of service of the present invention enables the multi-hop wireless network to have high channel throughput, small access delay, low packet discarding rate, guaranteed QoS, simple transceiver equipment requirements, and multi-hop application It can be used as a mobile ad hoc network (or mobile ad hoc packet wireless Ad Hoc network), wireless access network and other mobile wireless communication networks under the condition of no central control node. A method for users to share wireless channel resources.

The technical solutions of the present invention will be described in further detail below with reference to the accompanying drawings and embodiments.

Description of drawings

FIG. 1 is a flowchart of Embodiment 1 of a multiple access method supporting quality of service according to the present invention;

FIG. 2 is a flowchart of Embodiment 2 of the multiple access method supporting quality of service according to the present invention;

FIG. 3 is a flow chart of Embodiment 3 of the multiple access method supporting quality of service according to the present invention;

FIG. 4 is a sequence diagram of real-time service node access in Embodiment 4 of the multiple access method supporting quality of service according to the present invention;

FIG. 5 is a sequence diagram of non-real-time service node access in Embodiment 5 of the multiple access method supporting QoS of the present invention.

Detailed ways

Example 1:

FIG. 1 is a flow chart of Embodiment 1 of the multiple access method supporting QoS of the present invention, as shown in FIG. 1 , specifically including the following steps:

Step 1. The node judges the service type according to the service group to be sent. If it is a real-time service, the node sends an FB packet declaring the real-time service type. Packet length, the above-mentioned nodes enter the competition stage, and perform step 2; if it is a non-real-time service, the node continues to listen to a mini-slot of the FB packet length, if it does not hear the FB packet declaring the real-time service type sent by the real-time service node , the above-mentioned nodes enter the competition stage and execute step 2;

Wherein, the above competition stage is a stage before the node obtains the channel access right, and in this stage, the node sends one or more FB packets to obtain the channel access right. After the node obtains the channel access right, it enters the transmission stage and sends service packets.

Step 2, the node that is allowed to enter the competition stage determines the number of the beginning mini-slot and FB grouping of sending FB packets; whether the node listens to the channel before the determined beginning mini-slots and whether the mini-slots are all in idle state, if so , then go to step 3; otherwise, go back to step 1;

Step 3, the node then sends one or more (determined number) FB packets to judge whether the channel is in an idle state at this time, if it is judged that the channel is in an idle state according to the monitoring result, it means that no higher priority service packets are sent If the node is sending FB packets, the node obtains the channel access right, and executes step 4; if it is judged that the channel is busy according to the listening result, it means that there are nodes sending higher priority service packets sending longer FB packets, then The node fails to compete and backs down, returning to step 1;

Step 4. The node that has obtained the channel access right enters the transmission phase to send service packets.

Among them, the announcement forecast in step 1 (declaring the FB group of the real-time service type) ensures that the real-time service first enters the competition stage and obtains the channel access right first, and the non-real-time service can only be sent when no real-time service participates in the competition, that is, there is no announcement forecast Only then can they enter the competition stage.

In this embodiment, the real-time service and the non-real-time service firstly distinguish the service types through the statement, and then use the mechanism of short burst competition reservation channel and conflict resolution to ensure that the real-time service group can quickly access the channel and obtain the right to use the channel. The business packet transmission is completed prior to the general non-real-time business packets.

In Embodiment 1 of the present invention above, sensitive carrier sensing is used to judge the channel occupancy within the two-hop range of the node, so that collisions that may be caused by hidden terminals can be avoided. Specifically, in a wireless network, the distance at which the receiver can monitor the carrier of the transmitter is about twice the distance at which the packet can be received correctly, that is, by listening to the signal strength of the carrier in the channel at the physical layer, the node can control ( The Media Access Control (MAC) sublayer judges whether the channel is occupied within the range of two hops, so as to avoid the hidden terminal problem.

Example 2:

As shown in FIG. 2, it is a flow chart of Embodiment 2 of the multiple access method supporting QoS of the present invention. Compared with the previous embodiment, it also includes before step 1:

Step 0. When a node has a service and needs to access the channel, the node first monitors the channel for a window time, and judges whether the channel is in an idle state at this time. If the channel is in an idle state during the listening window time, then perform step 1; If the channel is busy within the listening window, the node repeats step 0.

Compared with the previous embodiment, the return step 1 in steps 2 and 3 is replaced by return step 0; in step 3, it is judged whether the channel is in an idle state at this time by listening to a mini-slot of the channel . In addition, compared with the previous embodiment, the following steps are also included after step 4:

Step 5, wait to receive the message of feedback acknowledgment grouping, judge whether to receive the feedback acknowledgment (acknowledgment, hereinafter referred to as ACK) grouping message after the receiving node correctly completes the service grouping, if correctly receive the message of ACK grouping, then execute step 6; Otherwise , return to step 0;

Step 6. Complete the transmission of this service packet, and delete the service packet that has been transmitted and received correctly from the buffer queue.

The two embodiments of the above-mentioned multiple access method supporting quality of service in the present invention propose a multiple access method supporting quality of service by declaring the service type, and nodes perform competition and conflict resolution by sending forecast bursts during the competition phase The technical solution ensures that real-time service packets can be accessed to the channel more preferentially, and greatly reduces possible packet collisions during the transmission phase.

Example 3:

FIG. 3 is a flow chart of Embodiment 3 of the multiple access method supporting QoS of the present invention, as shown in FIG. 3 , specifically including the following steps:

Step 1. Nodes with real-time services and non-real-time services are distinguished through declarations: the node listens to the channel for a window time T _win before accessing the channel. If the channel is idle within this time, the node judges the service type according to the service group to be sent. That is, the node (real-time service node) that has real-time service grouping to send then sends the FB grouping of a declaration service type immediately after _Twin is idle, enters the competition stage; Has the node (non-real-time service node) that non-real-time service grouping will send Then continue to listen to a micro-slot of FB length after _Twin is idle, if there is no statement from the real-time service node, the non-real-time service node enters the competition stage; otherwise, the non-real-time service node retreats;

Step 2, according to the priority and time delay situation that will send business grouping, the node that enters the contention stage determines the beginning mini-slot that will begin to send FB packet, represents the serial number of above-mentioned beginning mini-slot with I, and I is a positive integer. The competition phase can be divided into several mini-slots T _slot (T _slot <T _win ), the size of T _slot is the sum of the maximum signal propagation delay, the conversion time of sending and receiving, and the receiver monitoring time; in order to obtain satisfactory access efficiency, Can adjust respectively the size of real-time service and the non-real-time service competition stage mini-slot number according to load situation; Judging whether the burst mini-slot before beginning micro-slot (the 1st mini-slot) of channel is all in idle state, if The burst time slots before the Ith mini-slot are all idle, that is, the 1st to (I-1) mini-slots are all idle, indicating that no other adjacent nodes start to send FB packets, and this node starts from the I-th micro-slot Slot begins to send FB grouping, executes step 3, if detect the FB grouping that node sends in the time slot before the 1st mini-slot, then this node no longer joins competition, returns to step 1;

Step 3, start from the 1st mini-slot, the node that will send the FB packet starts to send the predetermined number of FB packets according to the priority and the time delay situation of the service packet to be sent by it, and represents the above-mentioned predetermined number with K; Send K After FB groups of FBs, the node monitors the channel for an observation time T _obs (T _obs = T _slot ) to determine whether the channel is idle at this time. If the channel is idle, the node obtains access and determines that the access is successful , then execute step 4, if the channel is busy, it means that there are nodes sending higher priority service packets sending longer FB packets, then the node fails this competition and backs down, then returns to step 1;

Step 4. The node sending the FB packet successfully obtains the channel access right through competition, and immediately sends the service packet. The length of the service packet should be much larger than the length of the FB packet, so as to ensure that the protocol has a relatively small overhead; the node waits for the receiving node ACK packet feedback after correct reception, if the ACK packet is received correctly, it means that the business packet transmission is successful, then go to step 5, otherwise, it means that the business packet has not been received correctly, the node waits to enter a new round of competition stage, and returns to step 1 , re-access and retransmit the packet;

Step 5. Complete the transmission of this service packet, delete the packet that has been transmitted and received correctly from the buffer queue, and start the competition and sending process of the next packet according to the node service load. .

Wherein, the selection and determination of starting mini-slot (I mini-slot) in step 3 meet the probability distribution with packet priority and time delay as parameters, and are less than the total number of competition time slots allocated to this kind of service. Specifically, I may be subject to a truncated geometric probability distribution with parameter q, and the size of q is related to the priority and delay of the service packets to be sent. The number K of FB packets to be sent, that is, the length of the FB packets, is determined by the priority and delay of the service packets to be sent. Specifically, the number of FB packets sent by the node from the Ith mini-slot is K, and the time length is K T _FB (T _FB = T _slot ), the value of K should be consistent with the priority and time of the service packets to be sent. The higher the priority, the greater the K; according to the earliest deadline first (EDP) criterion, the size of K should be proportional to the delay of the real-time service group, and the delay of the above-mentioned real-time service group is represented by D , namely K∝D/D _max , where D _max is the maximum allowable delay of real-time service packets. Therefore, the node with the higher priority and the earliest invalid packet starts to send the longer FB packet in the earlier time slot, that is, the node with the longer FB packet enjoys a higher access right. When there is a heavy traffic packet load, the contention time slot can be appropriately increased in order to obtain satisfactory access efficiency.

When sending FB packets, it is stipulated that the channel can only send FB packets when all the mini-slots before the start of the mini-slot are idle, that is, the earliest competing nodes are allowed to send FB packets. Nodes that start transmitting in the same mini-slot have the right to enter the list of transmission candidates, and they are the nodes with the highest service priority.

In the above embodiment 3 of the multiple access method supporting QoS of the present invention, the listening window time _Twin determines that there is no ongoing transmission and contention in the channel. Before entering the competition stage, nodes rely on FB packets that declare real-time service types to distinguish the sending priority of different service packets. Real-time service nodes send FB packets and enter the competition stage first; non-real-time service nodes listen to the statement sent by real-time service nodes The FB group of the service type can enter the competition stage when no real-time service node participates in the competition.

In addition, in Embodiment 3 of the multiple access method supporting quality of service of the present invention, the contention access and service packet transmission are separated, and the conflict resolution mechanism of predicting burst is used in the contention stage to make the real-time service group obtain preferentially by declaring Access, and solve the conflict problem of multiple business nodes. In the transmission stage, the short FB collision is used to replace the collision of the long service packet in the service packet transmission stage. The reduction of the collision probability improves the network throughput and reduces the delay of the service packet, so that the network performance is greatly improved.

Example 4:

FIG. 4 is a sequence diagram of real-time service node access in Embodiment 4 of the multiple access method supporting QoS of the present invention. The node ( Taking the access process of real-time service nodes) A and B as an example, the access and sending process of real-time packets in the present invention will be further described in detail. As shown in Figure 4, it specifically includes the following steps:

Step 1, after the real-time service node A and the real-time service node B monitor the channel T _win time, confirm that the channel state is idle, and enter the competition stage _T1 after sending a FB packet declaring the real-time service type respectively;

Step 2, according to the priority of the business grouping type and the time delay situation, utilize the truncated geometric probability distribution to determine the beginning micro-slot of the FB of the real-time service node A and the real-time service node B, that is, determine the value of I: if the real-time service node A and The real-time service Node B chooses to start sending FB with the same starting mini-slot, that is, I is the same, for example, I is 3, and no FB packets are sent in the first to second mini-slots of the competition stage _T1 before this, indicating that At present, the service packets to be sent by the real-time service node A and the real-time service node B are service packets with the highest priority, therefore, both the real-time service node A and the real-time service node B are allowed to send FB packets to compete for the channel;

Step 3, the real-time service node A that allows to send FB grouping and the real-time service node B start to send respectively the FB grouping of certain length (predetermined number) from the 1st mini-slot to compete, and the quantity K of FB grouping is determined by the number K of service grouping Determined by the priority and delay, the higher the priority and the longer the delay, the higher the priority of the packet, and the greater the K of the node where it is located; if the real-time service node A can send 4 FB packets, and the real-time service node B needs The service group sent can only send 2 FB groups due to the small time delay; the real-time service node A and the real-time service node B will respectively pre-determined number of FB groups (the real-time service node A is 4 and the real-time service node B is 2 ) after sending is completed, listen to the channel T _obs time, the number of FB packets sent by the real-time service node B is small, and the sending is completed earlier, and it can be heard that the real-time service node A is still sending FB packets within T _obs , that is, Knowing that there are service packets of other nodes with higher access priority, the real-time service node B backs off and returns to step 1 to re-access; after the real-time service node A completes sending, it becomes the longest FB among the nodes currently sending FB packets The number of nodes in the group, so the real-time service node A detects that the channel is idle in T _obs , thus confirming the success of the competition and obtaining access;

Step 4. The accessing real-time service node A enters the transmission phase T ₂ , sends a service packet (Packet, PKT for short), and receives an ACK packet. If the ACK from the receiving node is received within a predetermined time, it means that the transmission is successful. Execute step 5; otherwise, return to step 1 and resend the packet according to the retransmission mechanism;

Step 5. According to the condition of the cache queue, continue to access and send or turn to an idle state.

Example 5:

Fig. 5 is a non-real-time service node access sequence diagram of embodiment 5 of the multiple access method supporting quality of service according to the present invention. Taking the access process of nodes (non-real-time service nodes) C and D as an example, the process of accessing and sending non-real-time packets in the present invention is further described in detail. The competition process of non-real-time grouping is different from real-time business only in step 1, as shown in Figure 5, which specifically includes the following steps:

Step 1. After non-real-time service node C and non-real-time service node D listen to the channel for T _win time, confirm that the channel state is idle, and continue to listen to the declared time slot, and neither of them receives any real-time packet service node to send from the neighboring nodes FB grouping of the statement, at this time the non-real-time service nodes C and D enter the competition stage T ₁ ;

Thereafter, steps 2 to 5 of the non-real-time service nodes C and D accessing the competition stage _T1 and the transmission stage _T2 are similar to the corresponding steps of the real-time service nodes A and B shown in FIG. 3 , and will not be repeated here.

The embodiment of the multiple access method supporting quality of service of the present invention adopts the strategy of distinguishing priority of service groups. When the real-time service group node determines that it will access the channel, it first sends a declaration forecast, so it can start sending FB groups first and compete , so that the delay of real-time services can be guaranteed to the greatest extent. Especially when the business load is heavy, it is given priority to ensure that the nodes sending real-time business packets can obtain the access channel quickly, while the nodes sending non-real-time business packets can do best-effort transmission guarantee through the retransmission mechanism.

In addition, the embodiment of the multiple access method supporting quality of service in the present invention also ensures the fairness of the nodes accessing the channel. Nodes compete for channel access rights through FB packets, and the length of FB packets is determined by the priority and delay of service packets. The delay of the service packet of the node with more sending times should be relatively small, so it cannot always occupy the right to use the channel; the node with more serious delay can obtain priority access under the same priority, ensuring that the node Fairness at access time.

Each node in the embodiment of the multi-access method supporting quality of service of the present invention has only one half-duplex transceiver, and the equipment requirements are simple. In addition, the embodiments of the QoS-supporting multiple access method of the present invention are applicable to multiple multi-hop node access structures connected through broadcast media, and have a wide range of applications.

Those of ordinary skill in the art can understand that all or part of the steps for realizing the above-mentioned method embodiments can be completed by hardware related to program instructions, and the aforementioned program can be stored in a computer-readable storage medium. When the program is executed, the It includes the steps of the above method embodiments; and the aforementioned storage medium includes: ROM, RAM, magnetic disk or optical disk and other various media that can store program codes.

Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: it can still be Modifications are made to the technical solutions described in the foregoing embodiments, or equivalent replacements are made to some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims (10)

1, a kind of multiple access method of supporting service quality is characterized in that, comprising:

Step 1, node are judged type of service according to the traffic packets that will send, if real time business, described node then sends the forecast burst group of a statement type of service, execution in step 2; If non-real-time service, described node is then intercepted the mini-slot of a forecast burst group length, if do not listen to the forecast burst group of statement real time business type, then execution in step 2;

The quantity that step 2, described node are determined to send the beginning mini-slot of forecast burst group and sent forecast burst group, described node is intercepted the mini-slot of channel before described beginning mini-slot and whether all is in idle condition, if then execution in step 3; Otherwise, then return step 1;

Step 3, described node send one or more forecast burst group, judge whether channel is in idle condition, if then execution in step 4; Otherwise, then return step 1;

Step 4, described node access channel send traffic packets.

2, the multiple access method of support service quality according to claim 1, it is characterized in that the forecast burst group that node described in the described step 1 sends a statement type of service is specially: described node sends a forecast burst group of carrying the statement real time business type of real time business sign.

3, the multiple access method of support service quality according to claim 1, it is characterized in that the forecast burst group that node described in the described step 1 sends a statement type of service is specially: described node sends the forecast burst group of a length much smaller than the statement real time business type of traffic packets length.

4, the multiple access method of support service quality according to claim 1 is characterized in that, also comprises the steps: that node intercepts window time of channel before the described step 1, if channel idle, then execution in step 1.

5, the multiple access method of support service quality according to claim 1, it is characterized in that the quantity that node described in the described step 2 determine to send the beginning mini-slot of forecast burst group and sends forecast burst group is specially that " described node determines to send the beginning mini-slot of forecast burst group and the quantity of transmission forecast burst group according to priority that will send traffic packets and time delay.

6, the multiple access method of support service quality according to claim 1 is characterized in that, judges in the described step 3 whether channel is in idle condition and is specially: intercept mini-slot of channel, judge whether channel is in idle condition.

7, the multiple access method of support service quality according to claim 1 is characterized in that, also comprises after the described step 4:

Step 5, wait receive the message of feedback acknowledgment grouping, if correctly receive the message of feedback acknowledgment grouping, then execution in step 6; Otherwise, return step 1;

Step 6, the traffic packets that deletion is finished transmission and correctly received from the buffering formation.

8, the multiple access method of support service quality according to claim 5, it is characterized in that, described node determines that according to priority that will send traffic packets and time delay the beginning mini-slot that sends forecast burst group is specially: described node is the probability distribution of parameter according to the priority and the time delay that will send traffic packets with the node that enters the competitive stage, determines to send the beginning mini-slot of forecast burst group.

9, the multiple access method of support service quality according to claim 8, it is characterized in that, described node is the probability distribution of parameter according to the priority and the time delay that will send traffic packets with the node that enters the competitive stage, determine that the time slot that described node begins to send is specially: described node distributes according to will send the priority of traffic packets and brachymemma geometric probability that time delay is parameter with the node that enters the competitive stage, determines the beginning mini-slot of transmission forecast burst group.

10, the multiple access method of support service quality according to claim 5, it is characterized in that described node determines that according to priority that will send traffic packets and time delay the quantity that sends forecast burst group is specially: described node is the many more and definite quantity that sends forecast burst group of the preferential criterion that lost efficacy the earliest according to the high more quantity of priority.

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