CN103957085A - Media access control method for wireless mesh network based on network coding - Google Patents
Media access control method for wireless mesh network based on network coding Download PDFInfo
- Publication number
- CN103957085A CN103957085A CN201410216133.2A CN201410216133A CN103957085A CN 103957085 A CN103957085 A CN 103957085A CN 201410216133 A CN201410216133 A CN 201410216133A CN 103957085 A CN103957085 A CN 103957085A
- Authority
- CN
- China
- Prior art keywords
- node
- packet
- general data
- data bag
- coded data
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
- 238000000034 method Methods 0.000 title claims abstract description 86
- 101100127285 Drosophila melanogaster unc-104 gene Proteins 0.000 claims description 12
- 238000000205 computational method Methods 0.000 claims description 7
- 230000001186 cumulative effect Effects 0.000 claims description 7
- 230000015572 biosynthetic process Effects 0.000 claims description 6
- 230000007246 mechanism Effects 0.000 abstract description 17
- 238000004364 calculation method Methods 0.000 abstract description 2
- 238000012544 monitoring process Methods 0.000 abstract description 2
- 238000002474 experimental method Methods 0.000 description 34
- 238000004891 communication Methods 0.000 description 23
- 230000008569 process Effects 0.000 description 23
- 230000005540 biological transmission Effects 0.000 description 22
- 238000011160 research Methods 0.000 description 11
- 238000012360 testing method Methods 0.000 description 10
- 101100172132 Mus musculus Eif3a gene Proteins 0.000 description 7
- 239000007787 solid Substances 0.000 description 7
- 230000009467 reduction Effects 0.000 description 6
- 238000004088 simulation Methods 0.000 description 6
- 238000010586 diagram Methods 0.000 description 5
- 239000000284 extract Substances 0.000 description 5
- 230000008901 benefit Effects 0.000 description 4
- 230000008859 change Effects 0.000 description 4
- 238000000151 deposition Methods 0.000 description 4
- 238000004422 calculation algorithm Methods 0.000 description 3
- 238000012545 processing Methods 0.000 description 3
- 238000012790 confirmation Methods 0.000 description 2
- 230000007547 defect Effects 0.000 description 2
- 238000009826 distribution Methods 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 238000005516 engineering process Methods 0.000 description 2
- 238000012423 maintenance Methods 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- 230000006855 networking Effects 0.000 description 2
- 238000003860 storage Methods 0.000 description 2
- 238000012546 transfer Methods 0.000 description 2
- 238000002834 transmittance Methods 0.000 description 2
- 102000006479 Heterogeneous-Nuclear Ribonucleoproteins Human genes 0.000 description 1
- 108010019372 Heterogeneous-Nuclear Ribonucleoproteins Proteins 0.000 description 1
- 241000396836 Trinodes Species 0.000 description 1
- 230000001133 acceleration Effects 0.000 description 1
- 239000000654 additive Substances 0.000 description 1
- 230000000996 additive effect Effects 0.000 description 1
- 238000013459 approach Methods 0.000 description 1
- 230000007812 deficiency Effects 0.000 description 1
- 238000013461 design Methods 0.000 description 1
- 201000010099 disease Diseases 0.000 description 1
- 208000037265 diseases, disorders, signs and symptoms Diseases 0.000 description 1
- 230000006870 function Effects 0.000 description 1
- 230000003993 interaction Effects 0.000 description 1
- 230000002452 interceptive effect Effects 0.000 description 1
- 238000011430 maximum method Methods 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 230000002969 morbid Effects 0.000 description 1
- 238000011084 recovery Methods 0.000 description 1
- 238000011946 reduction process Methods 0.000 description 1
- 238000007493 shaping process Methods 0.000 description 1
- 208000024891 symptom Diseases 0.000 description 1
- 230000001360 synchronised effect Effects 0.000 description 1
Landscapes
- Mobile Radio Communication Systems (AREA)
Abstract
The invention discloses a media access control method for a wireless mesh network based on network coding. The media access control method comprises the steps of a data package receiving stage, a data package transmitting stage and an ACK monitoring stage. According to the protocol, a network coding mechanism is introduced into a media access control layer, and throughput is increased compared with the traditional media access control method based on conflict avoidance. The media access control method is high in decoding success rate, less in control expenditure, low in calculation consumption of hardware, strong in portability, good in compatibility and capable of relieving network congestion partially.
Description
Technical field
The present invention relates to radio network technique field, be specifically related to a kind of wireless network medium access control method of coding Network Based, being applicable to provide high-throughput is the wireless mesh network of service object.
Background technology
How improving data throughout is the emphasis research topic of wireless mesh network.The in the situation that of channel medium resource-constrained, for access device provides the data transport service of the high high-quality of handling up of high bandwidth, the physical layer of wireless mesh network, media access control layer are proposed to high requirement.Meanwhile, the networking equipment price general charged of wireless mesh network is cheap, and data buffer storage ability, calculation process are limited in one's ability, under harsh like this hardware condition, guarantees that the operation of media access control method efficient stable is a critical problem equally.Because network code has remarkable effect to throughput hoisting, in addition, network code needs extra hardware resource, so the wireless mesh network media access control method that coding Network Based has stability autgmentability concurrently is a breach.
Wireless mesh network has had extensive use in recent years.Be mainly the crowded places such as enterprise, school, market, station wireless network access solution is provided.Be primarily characterized in that dispose convenient, with low cost, automatic network-building, autgmentability is high.At cable network, disposing difficulty, in the situation that autgmentability cannot guarantee, use wireless mesh network to substitute underlying basis facility, is the most simple and effective way.Utilize wireless mesh network to provide the key of Internet access service to be, how for numerous wireless terminals provide height, to handle up, stable data transmission mechanism.In prior art, in order to improve the data throughout of wireless mesh network, mainly contain following several research:
The first kind: physical layer is high bandwidth more; The shortcoming of the method is by hardware technology, improves single-frequency bandwidth or multifrequency multiplexing, and technical difficulty is large, has increased radio reception device price, high to terminal equipment requirement, belongs to a kind of solution of curing the symptoms, not the disease.While HF communication, multi-band communication, the cost that exchanges throughput for is the electromagnetic pollution in wireless signal space.
Equations of The Second Kind: network layer chance route; The shortcoming of the method is that additional communication expense is large, controls complexity, realizes difficulty large.Routing Protocol is generally operational in network layer, and normally the work control information of use of chance route needs additional transmissions to complete, and this causes data link layer to pay overhead.And the chance route implementing technical difficulty of getting up is large, and the consumption of hardware resource is not also had to detailed research.
The 3rd class: stricter media access control method; The shortcoming of these class methods is the tacit agreements that acquire a certain degree between requirement wireless netted network node and node, that is to say and knows each other the other side is about to what is done, and between node, clock synchronous requires high.And, once certain equipment goes wrong in network, also will face same problem with other equipment of its cooperation.Network universality, robustness, autgmentability all have problems.
The 4th class: network layer adds network code mechanism; The shortcoming of these class methods is that network code is independent of media access control layer and TCP layer, need to provide reliable broadcast service by extra radio broadcasting agreement.Meanwhile, these class methods can be in network the larger virtual bottleneck node of manufacture scope, cause network congestion on a large scale.And the congestion control of network layer is theoretical, can cause these class methods normally to work.In addition, these class methods are also seldom considered the consumption to hardware resource, implement technical difficulty large, and apparatus adaptability is poor.
The network code mechanism that is independent of media access control layer and TCP layer, each node wants chance to monitor the packet of neighbor node broadcast, is placed in the buffer memory of oneself, during in order to decoding, uses.Doing like this defect of bringing mainly contains: 1) to local cache, consumption is catastrophic to immoderate monitoring neighbours packet.Its buffer memory consumes except link load, affected by neighbours' number.And these packets that listen to whether can be utilized be also unknown number.The opportunity cost that throughput hoisting is paid is too high, and application is uncertain high, poor controllability.2) node prediction neighbours whether buffer memory certain packet, Main Basis link transmission success rate ETX index is carried out probability Estimation.According to ROC Calibration Theory, the estimation model of its use has fixing error rate.High at number of nodes, terminal equipment is many, and Communication Jamming is large, and in the poor situation of radio link quality, this fixed error rate can cause quite a few encoded packets not to be correctly decoded, thereby has wasted more hardware resources and channel resource.3) this mechanism is conventionally pursued at every turn and is encoded and all packet as much as possible is organized in once, to reduce the number of broadcast times of individual node.But this way is also improper in practice.One may not be all destination node can be correctly decoded, two reliable Radio Broadcasting Agreements, when destination node is many, tend to restriction node communication in larger scope, cause full wafer regional channel utilance low.
Summary of the invention
The wireless mesh network media access control method of coding Network Based is significantly different from common media access control method, deficiency for existing wireless mesh network media access control method in throughput hoisting ability and network layer are introduced many defects of encoding mechanism, the present invention proposes a kind ofly highly to handle up, low consumption, has the media access control method of universality robustness concurrently.
In order to realize above-mentioned task, the technical solution used in the present invention is:
A wireless mesh network media access control method for coding Network Based, in this wireless mesh network, receives after the packet that neighbor node sends when a node, judges that this packet is general data bag or coded data packet:
If coded data packet is decoded to this coded data packet, successfully decoded obtains the general data bag needing, unsuccessful this coded data packet that abandons of decoding;
If general data bag judges whether this general data bag reaches the formation condition of coded data packet, as reached, it is encoded, and the coded data packet obtaining after coding is broadcasted to neighbor node;
Formation condition and the cataloged procedure of coded data packet are as follows:
In this wireless mesh network, node A has two neighbor nodes at least, if the forwarding queue of initial time node A is empty, from initial time, start: node A receives the general data bag p2 that neighbor node sends, in forwarding queue, find a general data bag p1, if exist p1 to meet formula 1 and formula 2 simultaneously, p1 and p2 coding are become to coded data packet p;
In formula 1, s1, s2 are respectively the source node MAC Address of packet p1, p2, and d1, d2 are respectively the MAC Address of p1, p2 next-hop node, and t1, t2 are respectively the time that p1, p2 reach node A, and θ value is 0.3 second;
In formula 2, r and c are respectively node A from initial time, receive in the accumulative total number of general data bag and the forwarding queue of node A that neighbor node sends, meet the accumulative total number of the general data bag of formula 1, wherein r at every turn cumulative 1, c at every turn cumulative 2, ξ value be 0.08.
Further, general data bag p1 and p2 become coded data packet p through also exclusive disjunction coding, are specially:
The MAC Address of general data bag p2 destination node and p1 destination host MAC Address are done to also exclusive disjunction, and acquired results is inserted the destination host MAC field of p1; General data bag p2 source host MAC Address and p1 source host MAC Address are done to also exclusive disjunction, and acquired results is inserted the MAC field of the source node of p1; The data division of the data division of p2 and p1 is done to also exclusive disjunction, and acquired results is inserted the data division field of p1; If the data division length of p1 and p2 is inconsistent, 0 cover is filled out to by the shorter square tail portion of length, the new packet of generation is coded data packet p.
Further, in this wireless mesh network, in each node, be provided with resource queue, when being bundled into merit by a general data, node sends to after another node, this general data bag is moved into resource queue from forwarding queue, and is that this general data bag starts a count-down device, count-down device initial value is θ, after count-down device makes zero, this general data Bao Cong resource queue is removed.
Further, when node is received after a coded data packet, it is carried out to decode operation: node is found the general data bag corresponding with the coded data packet of receiving from the resource queue of oneself, the general data bag finding and the coded data packet of receiving are carried out to also exclusive disjunction, obtain the general data bag needing.
Further, node A generates after coded data packet p, and the step that p is broadcasted is as follows:
Step S1, creates broadcast RTS frame, the MAC Address of the next-hop node of general data bag p1, p2 write in RTS frame, and definite channel occupancy duration Tb, the call duration time field of Tb being added to broadcast RTS frame, Tb computational methods are as follows:
Tb=5 * SIFS+ (82+L) * t
0(formula 3)
In formula 3, SIFS is the shortest stand-by period constant of 802.11 agreement regulations, and L is the length of coded data packet p, t
0for transmitting a needed time of byte, by link bandwidth, determined;
Step S2, node A broadcast RTS frame request channel;
Step S3, neighbor node is received after RTS frame, determines and oneself replys the stand-by period Tcts of RTS frame, and after the stand-by period, reply CTS frame to node A; Tcts computational methods are as follows:
In formula 4, the MAC Address that iMAC is this neighbor node, d1, d2 are respectively the MAC Address of the next-hop node of packet p1, p2;
Step S4, node A sends broadcast RTS frame, waits for 2 * SIFS+28 * t
0after time, check the CTS frame condition of receiving, if receive respectively the CTS frame that the next-hop node of p1, p2 is replied, node A waits for that SIFS starts after the time to send coded data packet p, otherwise node A enters back-off wait.
Advantage of the present invention mainly contain following some:
1. increased network throughput;
Owing to introducing network code mechanism to data link layer, the present invention is from having promoted in essence network throughput.In the constant situation of hardware condition, use the present invention can improve the network data handling capacity of 7%-40%.
2. transplantability is strong, compatible good;
Good backward compatible due to CSMA/CA has been done, therefore support that equipment of the present invention can be with not supporting equipment proper communication of the present invention, networking.Meanwhile, the present invention increases and has strengthened MAC sublayer, and other aspects of network are not formed to impact, and interface is transparent.
3. be decoded into power high, additional communication is few;
Different from other network code mechanism, the present invention uses ACK frame and data packet head to transmit necessary coded message, and node is not used ETX route chi to predict, therefore, and the phenomenon of cannot decoding that does not exist predicated error to bring.And the present invention does not rely on the control information of other agreements (as chance route), do not need to transmit between node independently control information.
4. hardware consumption is few;
Compare with other network code mechanism, this method is more focused on taking cache resources and computational resource.Node no longer chance is monitored the communication between neighbours, thereby the buffer memory consumption of storage decode resources is down to minimum.
5. part has solved network congestion problem;
In there is no the network of congestion control, when offered load is large, there is congestion phenomenon around in trunk roads bottleneck node and bottleneck node unavoidably.This method is exactly utilized the large advantage of bottleneck node transmission information amount, by possible data packet coding together.Thereby allow these packets fast by bottleneck node, reduce congestedly, slow down congested generation.
Accompanying drawing explanation
Fig. 1 is encoding mechanism principle and network design schematic diagram;
Fig. 2 is data transmission phase procedure chart;
Fig. 3 is data receiver phase process figure;
Fig. 4 is ACK frame listen phase procedure chart;
Fig. 5 (a) and Fig. 5 (b) are the structural representations of frame in the present invention;
Fig. 6 is coded data packet broadcasting process schematic diagram;
Fig. 7 is this programme overall flow figure;
Fig. 8 is that research offered load is determined schematic diagram to impact and the ξ of code machine meeting;
Fig. 9 is the experimental result picture of research θ to code machine meeting number affects;
Figure 10 (a), Figure 10 (b), Figure 10 (c), Figure 10 (d) are under identical ω, different θ, decode resources queue service condition figure;
Figure 11 (a), Figure 11 (b), Figure 11 (c), Figure 11 (d) are under different ω, the affect schematic diagram of θ on three kinds of node proportions;
Figure 12 (a), Figure 12 (b) are the experimental result picture of research offered load to each method performance impact;
Figure 13 (a), Figure 13 (b) are the experimental result picture of research link transmission success rate to each method performance impact;
Figure 14 (a), Figure 14 (b), Figure 14 (c), Figure 14 (d) are that research offered load is used the experimental result picture of impact on each method buffer memory;
Embodiment
Applicant disposes large-scale wireless mesh network in building, for Internet access service being provided to the equipment such as mobile phone, notebook computer, need the media access control method that throughput is high, compatibility is good, consumption of natural resource is few, to ensure the data service quality of each access device.The complex situations such as limited for node hardware condition, the demand of handling up is high, quality of wireless channel is poor, have proposed the wireless mesh network media access control method of coding Network Based.
This method is used network code mechanism to improve throughput, therefore when wireless mesh network is disposed, except network edge node, other nodes at least will have 2 neighbor nodes, and in all neighbor nodes, at least there is 1 pair of neighbor node of direct communication mutually, as shown in Figure 1.Node B, C, D are in the communication range of A, but node D is not in the communication range of B, only in this way, node A could encode to the round data on this link of B-A-D, D is in the communication range of B else if, and B will be directly passed to D data, and A can not obtain code machine meeting.
The all node locations of this method are fixed or are only had small movement.The communication radius of all nodes is constant.In each node, all arrange and safeguard three queues: forwarding queue, for depositing the packet that will send to other nodes, can be general data bag, can be also coded data packet; Resource queue, the general data bag using while decoding for depositing; Reduction queue, sends for depositing coded data packet the general data bag that unsuccessfully rear restoring operation is used.
Network code that this method is used mechanism, its core concept is, and as shown in Figure 1, first node D sends general data bag p1 to B, and centre will forward through transit node A; A receives after p1, at once p1 is not transmitted to B, but by p1 buffer memory a period of time; Node B sends another general data bag p2 to node D, needs equally A transfer; A receives after p2, together with p2 is encoded to p1, coded data packet p1 ⊕ p2 is broadcasted away, and Node B and D receive after encoded packets p1 ⊕ p2, all carry out decode operation, the general data bag that obtains needing separately.Whole process consumes three communication cycles, reduces by a communication cycle, thereby reach the object that promotes throughput than original " reception---forwarding " process.
This method be take 802.11 agreements as basis, and the general data bag of using in scheme, is in 802.11 agreements, between two nodes for the packet of transfer data information.In this programme, broadcast RTS frame, coded data packet, three kinds of frame formats of coding ACK frame on the 802.11 original bases of agreement, have been increased, basic identical in the form of all kinds of frames and packet and 802.11, difference is to have increased at general data bag frame entity head the packet id field that length is 4B, at coded data packet frame entity head, has increased packet id field and data packet length field.Fig. 5 (a), Fig. 5 (b) have provided all Frames that use (bag) form, be therefore divided into Fig. 5 (a) and two figure of Fig. 5 (b), but its expression are a set of because picture is large; Table 1 is with the example that is exemplified as of Fig. 1, provided in the middle of the structure of the packet that this programme is used (frame), the explanation of the field different from packet (frame) implication identical in 802.11, except these fields, all the other fields are identical with the implication of field in 802.11 agreements.Wherein " frame " is data link layer concept, is the unit of packet.In this programme, " frame " is identical with the implication of " bag ", all refers to contain control information and data message at interior bit sequence.In this programme, be emphatically the discussion to frame or bag internal structure, therefore all available " bag " replacements of the place of all appearance " frame ", as " coded frame data " refers to " coded data packet ".
Table 1
One, the inventive method detailed step
In wireless mesh network structure of the present invention, except fringe node, all the other nodes all carry out forwarding and the processing procedure of packet according to this method, the thing that these nodes are done is identical, therefore for the ease of clearly introducing this programme, the model shown in Fig. 1 take below as example, scheme is simplified to an information interaction unit, the information interactive process between A, B, tri-nodes of D illustrates; A node in this model can be in mesh network except fringe node a node arbitrarily, and the neighbor node that B, D node are A, and D need to send general data bag p1 to B, B need to send general data bag p2 to node D simultaneously.
In this programme, at different intra-nodes, produce data packet receive stage, Packet Generation node and ACK frame listen phase, respectively each stage is described in detail below.
1. data packet receive stage
In this programme, from source node, send to the packet of destination node, when source node obtains this packet, be called general data bag, this packet is identical with the packet structure in 802.11, unique difference is that frame entity head at this packet has increased the packet id field that length is 4B, and this id field is generated by source node.General data wraps in the transmittance process of each node in network, if it meets encoding condition at certain Nodes, just two general data packet encoders is become to coded data packet broadcast; As it does not meet encoding condition, this general data bag equally forwards according to the general data bag in the middle of 802.11 agreements, thereby complete the transmittance process of this Nodes, therefore a node receives that the packet that neighbor node is sent just has two types: general data bag and coded data packet.
When a node A receives after the packet that neighbor node sends, judge that this packet is general data bag or coded data packet, as shown in Figure 3;
Step S10, the type of specified data bag
Node physical layer is received after complete errorless packet, according to packet MAC header length, judges that this is a general data bag or coded data packet.Frame is divided into three parts: frame head (Mac header), frame entity (body), FCS territory.If MAC header length is 30B, show to receive a general data bag, if MAC header length is 36B, show to receive a coded data packet.
For coded data packet, this coded data packet to be decoded, successfully decoded obtains the general data bag needing; Unsuccessful this coded data packet that abandons of decoding; Obtain after general data bag, node is equally processed this packet as the new packet receiving;
For general data bag, the packet ID that first node extracts this data packet frame entity head is denoted as idx, then in the resource queue of oneself, searches.If found the decode resources bag that comprises idx, illustrate that the general data bag of receiving was once a part for certain coded data packet, but that coded data packet is not successfully received, upper hop node is after coded data packet decoding, carried out retransmission operation, so node to remove the decode resources bag searching out.If can not find the decode resources bag that comprises idx, the general data bag of the receiving processing of can encoding is described.
Formation condition and the cataloged procedure of coded data packet are as follows:
The forwarding queue of initial time node A is set for empty, in forwarding queue, there is no packet.Each node is safeguarded two shaping variable r and c in buffer memory, four list lattice b.The initial time value of r and c is zero, and from initial time, the value of two variablees is always constantly cumulative; B deposits the supplementary of general data bag in forwarding queue.
The initial time is here the moment defining for the solution of the present invention is described, at this constantly, in the forwarding queue of node A, there is no packet.This initial time can be understood as node A and is arranged on the time point in sensor network, moment when sensor node is started working, from this constantly, the variable r safeguarding in node A and the value of c are just always cumulative since 0.
Node A receives after the general data bag p2 that neighbor node B sends, in the form b of forwarding queue by rear to general data bag p1 of front searching, if exist p1 to meet formula 1 and formula 2 simultaneously, p1 and p2 coding are become to coded data packet p;
In formula 1, s1, s2 are respectively the source node MAC Address of packet p1, p2, and d1, d2 are respectively the MAC Address of p1, p2 next-hop node, and node A can obtain by routing algorithm; T1, t2 are respectively the time that p1, p2 reach node A, and θ value is 0.3 second, and its deterministic process is shown in experiment two.
The given condition of formula 1 is, node A receives after general data bag p2, in its forwarding queue, exist packet p1 also not forward, and p1 and p2 meet: the next-hop node of p1 (destination node) is the source node of p2, the source node of p1 is the next-hop node (destination node) of p2, the time difference that p2 and p1 arrive node A is less than θ (being the copy of an in store p1 in the source node Hai resource queue of p1), meet after these conditions, be to provide in Fig. 1 example, D need to send general data bag p1 to B, B need to send general data bag p2 to this situation of node D simultaneously,
In formula 2, r be node A from initial time, receive the accumulative total number of the general data bag that neighbor node sends,, as long as A receives a general data bag, just the value of r is added to 1; In the forwarding queue of c dactylus point A, meet the accumulative total number of the general data bag of formula 1, can carry out the number of coded data bag, if the condition of a general data bag coincidence formula 1 can be encoded, the value of c cumulative 2; ξ is a fixed constant, and its value is 0.08; K is code switch, when k< ξ, illustrate that present node is operated in the situation of low load, or near network is providing service for application such as FTP, Streaming Medias, this general data bag does not need coding, and the general data bag according to 802.11 forwards; And during k> ξ, illustrate that the data flow direction of the present node of flowing through is enough complicated, and should adopt this method to carry out the coding of general data bag, the deterministic process of ξ value is shown in and tests one.
Step S11, the coding of general data bag
In this programme, to meeting the general data bag p1 of encoding condition and p2, through also exclusive disjunction coding, become coded data packet p, i.e. p=p1 ⊕ p2, is specially:
Node A puts into reduction queue by general data bag p2, and while sending unsuccessfully in order to coded data packet p, reduction process is used.Node A after destination node MAC field, increases a destination node 2MAC field in the MAC of p1 header, wherein writes the destination node MAC Address of p2; By the destination host MAC of p1 and the destination host MAC Address of p2, do also exclusive disjunction, acquired results is inserted the destination host MAC field of p1; By the source host MAC of p1 and the source host MAC Address of p2, do also exclusive disjunction, acquired results is inserted the source host MAC field of p1; After the frame solid data bag id field of p1, add packet ID, p1 frame solid data partial-length, the p2 frame solid data partial-length of p2; By the frame solid data part of p1, partly do also exclusive disjunction with the frame solid data of p2, acquired results is inserted the frame solid data part field of p1, if the data division length of p1 and p2 is inconsistent, 0 cover is filled out to by the shorter square tail portion of length; The new packet that both generate after encoding is coded data packet p.
Step S12, coded message transmission
After node A is encoded to general data bag p2 with p1 together with, make a coding ACK frame, the suffix ID1 field of this frame is inserted the packet ID of packet p1 frame header, and suffix ID2 field is inserted the packet ID of packet p2 frame header.Wait for that SIFS is after the time, node A sends to Node B by coding ACK frame.
Step S13, coded data packet decoding
A makes after coded data packet p, to neighbor node, broadcasts.When node D sends to packet p1 after node A, node D is moved into p1 resource queue from forwarding queue, and is that this general data bag p1 starts a count-down device, and count-down device initial value is θ, after count-down device makes zero, this general data Bao Cong resource queue is removed.The general data bag p1 being moved in resource queue is used when D receives that the coded data packet being generated by p1 is decoded.
Its neighbor node D receives the p of A broadcast, first from the head of the frame entity of this p, extracts packet 1ID, packet 2ID, packet 1 length, packet 2 length, is denoted as respectively id1, id2, l1, l2.Node D finds the general data bag corresponding with the coded data packet p receiving, the general data bag that frame entity head comprises id1 or id2 in the resource queue of oneself.After finding, this general data bag is denoted as to p3, if can not find p3, illustrates that p can not be successfully decoded, and abandons p.
Node D extracts packet ID and data packet length from p3, is denoted as respectively id3 and l3.If id3 equals id2, the destination node MAC field to p3 by the destination node 2MAC address reproduction of coded data packet p; By the destination host MAC Address of p3 and the coding destination host MAC Address of p, do also exclusive disjunction, acquired results is put into the destination host MAC field of p3; With the source host MAC Address of p3 and the coding source host MAC address of p, do also exclusive disjunction, acquired results is put into the source host MAC field of p3; By the coded data in the data division in p3 frame entity and p coded frame entity, partly do also exclusive disjunction, if acquired results length is greater than l2, intercept, only retain front l2 byte, and the result after intercepting is write to the frame solid data part of p3.When id3 equals id1, way is similar; The packet p2 that the p3 of new production obtains after decoding.
Node D, when decoding p, determines and replys ACK frame stand-by period Tack, then replys common ACK frame to node A, shows oneself to have received coded data packet, and packet is successfully decoded.Node D submits to network layer by the p3 packet of processing after p is successfully decoded.
The coded data packet decode procedure that note: step S13 partly introduces, the node D of take makes an explanation as present node, and if node A receives the coded data packet that other nodes are sent, be the same with the decode procedure of this part.The D of take is the explanation that the example that provides with Fig. 1 is carried out as present node makes an explanation, in fact in application process, the process that node A completes is all to occur in each node except fringe node, B-A-D be abstract out one for explaining the naive model of this programme, the process that B, D complete with A is in fact the same.
2. Packet Generation stage
Step S20, determines channel occupancy type
The length of first packet MAC header in the forwarding queue of node A judgement oneself, if 30B illustrates that this is a general data bag, the RTS-CTS flow operations according to 802.11.
If MAC header length is 36B, explanation will be broadcasted a coded data packet, as coded data packet p, as shown in 2.
Step S21, creates RTS frame
Create a broadcast RTS frame, the MAC Address of oneself is added to the source node MAC field of this frame, destination node 1MAC in the MAC header of p and destination node 2MAC field are copied to the corresponding field of this coding RTS frame, Fig. 1 institute representation model of take is example, and the MAC Address that is about to the next-hop node of general data bag p1, p2 copies to the MAC field of this broadcast RTS frame; Then determine channel occupancy duration Tb, add Tb to RTS frame traffic time field, Tb computational methods are as follows:
Tb=5 * SIFS+ (82+L) * t
0(formula 3)
In formula 3, SIFS is the shortest stand-by period constant of 802.11 agreement regulations, and L is the length of coded data packet p, t
0for transmitting a needed time of byte, by link bandwidth, determined; Fig. 6 is that coded data packet sends overall process schematic diagram, Tb starts to send broadcast RTS frame from node A to finish to send to Node B the time that ACK frame experiences, and comprises altogether 5 SIFS times, 1 broadcast RTS frame transmission time, 2 CTS frame transmission times, 1 coded frame data transmission time and 2 common ACK frame transmission times.Broadcast RTS frame length 26B, CTS frame and common ACK frame length are all 14B.
Step S22, node A broadcast RTS frame request channel;
Step S23, neighbor node is received after RTS frame, determines and oneself replys the stand-by period Tcts of RTS frame, and after the stand-by period, reply CTS frame to node A; Tcts computational methods are as follows:
In formula 4, iMAC is this neighbor node, as neighbor node D receives this RTS frame, is the MAC Address of D, and d1, d2 are respectively the MAC Address of the next-hop node of packet p1, p2, i.e. the MAC Address of B and D; Node D waits for that Tcts is after the time, if find there is no node around using channel, replys CTS frame to node A, shows oneself can communicate by letter with node A.At ensuing Tb-Tcts-40 * t
0in time, even if receive that again the RTS frame that other nodes send do not do any reply yet.If node D finds that channel is used around, directly lose the RTS frame that node A sends.The thing that Node B is done is identical with D.
Step S24, judges channel request result
Node A sends broadcast RTS frame, waits for 2 * SIFS+28 * t
0after time, check the CTS frame condition of receiving, if receive respectively the CTS frame that the next-hop node of p1, p2 is replied, channel request success is described, node A waits for that SIFS starts to send coded data packet p after the time, if only receive a CTS frame or do not receive CTS frame, the failure of specification request channel, node A enters back-off wait.
Node D receives after the coded frame data of A broadcast, carries out decode operation (detailed process is shown in step S13), and determines the stand-by period Tack that replys ACK frame, and Tack computational methods are as follows:
Wherein iMAC is the MAC Address of node D, and MACheader.DtMAC1 is the destination node 1MAC address of the coded data packet received of node D, the i.e. MAC Address of B; MACheader.DtMAC2 is destination node 2MAC address, the i.e. MAC Address of D.Node D waits for the Tack time, if encoded packets decoding is correct, replys common ACK frame to node A, otherwise directly abandons the coded data packet of receiving.The thing that Node B is done is identical with D.
Step S25, judges re-transmission state
After node A is sent p=p1 ⊕ p2, wait for 2 * SIFS+28 * t
0time, check the ACK frame condition of receiving.If node A receives respectively two ACK frames from Node B and node D, illustrate that B and D have received coded data packet p1 ⊕ p2 successfully decoding, at this moment node A removes p from forwarding queue, and finds p2 from the reduction queue of oneself, and p2 is removed.If an ACK frame is all confiscated, enter back-off wait.
If only receive the ACK frame that node D replys, and do not receive and illustrate that B could not correctly receive that coded data packet p maybe can not be correctly decoded by the ACK frame that B replys.Now, node A need to find general data bag p2 from the reduction queue of oneself, directly with p2, replaces the p1 ⊕ p2 in forwarding queue, then back-off wait.
If only receive the ACK frame that Node B is replied, and do not receive and illustrate that B could not correctly receive that coded data packet p1 ⊕ p2 maybe can not be correctly decoded by the ACK frame that D replys.Node A finds general data bag p2 from the reduction queue of oneself.Node A need to remove the destination node 2MAC field (address) in the MAC header of coded data packet p1 ⊕ p2; By the destination host MAC Address of coding destination host MAC Address and p2, do also exclusive disjunction, with acquired results, replace the coding destination host MAC Address of p; By the source host MAC Address of coding source host MAC address and p2, do also exclusive disjunction, with acquired results, replace the coding source host MAC address of p; Remove packet 2ID and packet 2 length of coded data packet frame entity head; With data division in the frame entity of coded data part in the frame entity of p and p2, do also exclusive disjunction, with acquired results, replace the coded data part of p; According to remaining packet 1 length of coded frame entity head, block coded frame entity, abandon redundance; Refresh the FCS field of p; Finally from reduction queue, remove p2.Like this, just coded data packet p is reduced into packet p1, then back-off wait.
3.ACK frame listen phase
Embodiment of the present invention ACK frame listen phase comprises upgrades resource queue, maintenance resources timer etc.Major function is the queue of management decode resources.At this one-phase, node not only will be intercepted the ACK frame that is about to send to oneself, also will be in back-off wait process, and the ACK frame transmitting between other nodes of idle listening.
Fig. 4 is ACK frame listen phase procedure chart, in conjunction with Fig. 1, Fig. 5 and Fig. 6, illustrates that the present embodiment ACK frame listen phase procedure chart concrete steps are as follows:
Step S30, determines ACK frame state.Node listens to after ACK frame, checks that whether the destination node MAC field of ACK frame is identical with the MAC Address of oneself.If identical, illustrate that this ACK frame is the confirmation of packet that oneself was sent just now, need to upgrade resource queue establishing resource timer; If not identical, illustrate that this ACK frame is that idle listening obtains, check whether this ACK frame is coding ACK frame, wherein whether comprises suffix id field, if do not contain suffix id field, directly this ACK frame is abandoned, otherwise, need maintenance resources timer.
Step S31, upgrades resource queue.Node B send general data bag p2 to node A after, wait for SIFS, if confiscate ACK frame, illustrate that p2 sends unsuccessfully, enters back-off wait.If receive ACK frame, the ACK frame no matter whether this ACK frame encodes, all illustrates that A has successfully received p2.Node B moves into resource queue by general data bag p2 from forwarding queue, and is that resource bag p2 starts a count-down device, and count-down device initial value is θ, after count-down device makes zero, resource Baop2Cong resource queue is removed.Because according to formula 1, count-down device makes zero, node A can not encode to p2 again.
Step S32, checks coded message.If the ACK frame that Node B is received belongs to coding ACK frame, illustrate that node A has not only successfully received general data bag p2, and p2 is arrived together with other data packet codings.Node B is extracted packet ID and is denoted as id1 from the suffix ID1 of ACK frame, i.e. the packet ID of general data bag p1 frame entity head.Node B stops the count-down device of opening for resource bag p2 in step S31, prevents that p2 from surprisingly being removed, and causes coded data packet p1 ⊕ p2 not decode.Node B changes the packet ID of general data bag p2 frame entity head into id1, so that step S13 operation.After this, in general data Baop2Cong resource queue, be removed and only have two kinds of situations to occur: the one, coded data packet p arrives and successfully decoding, and the 2nd, the packet that frame entity head is id1 arrives (step S13).
Step S33, upgrades count-down device.Node D send general data bag p1 to node A after, receive the confirmation ACK frame that node A replys, that is a common ACK frame, according to step S31, p1 is moved to the resource queue of node D, and a count-down device is being resource bag p1 timing.Although this posterior nodal point D is not used channel to send data, intercept the communication between other nodes in communication range always.Node A receives that Node B sends to its general data bag p2 and reaches after encoding condition, by p2 coding, and replys a coding ACK frame to Node B.This coding ACK frame of now node D meeting idle listening.The suffix ID1 that node D extracts coding ACK frame is denoted as id1, extracts suffix ID2 and is denoted as id2.It is id1 resource bag that node D searches frame entity head in resource queue, if found, illustrates that coding ACK frame that idle listening arrives, with own relevant, change the resource bag frame entity head finding into id2, and stops the count-down device of this resource bag; If can not find, illustrate that this coding ACK frame is irrelevant with oneself, directly abandoned.
Two, the determining of each relevant parameter in the inventive method:
Experiment one: the impact of research offered load on code machine meeting, and ξ's is definite;
Step 1, the initialization of emulation experiment scene:
It is 1400m that applicant simulates a length, and the wireless mesh network that width is 600m is wherein arranged 86 nodes.In this experiment, the communication radius of each node is 175m, and the link transmission success rate between node is recorded by physical environment.Each experiment simulation duration is 5s, ω packet of each node generation per second, and destination address is selected at random, and the length of each packet is 1000B, and link bandwidth is 54Mbps, and network layer is used minimum hop to count route, by ω, controls offered load.
Step 2, gets ω=50, and 100,150 ... 300, for the value of each ω, get θ=0.25s, 0.50s, 0.75s, 1.00s, therefore, has done 6 * 4 groups of assessments altogether.In order to guarantee the authenticity of experimental result, 1000 experiments have been carried out in every group of assessment, get the desired value of result as every group of final result.
Step 3, analyze and process experimental data:
Fig. 8 shows under different ω values, in step S23
the situation of change of (data flow complexity).The different θ values of not collinear representative in figure.From experimental result, can find out: (1), for different θ, data flow complexity has same tendency.(2), when ω <50, data flow complexity increases very fast; Along with ω increases, data flow complexity reduces gradually, then tends towards stability.(3) the data flow complexity curve distance of different θ is very near.These three observed result explanations, when offered load hour, node is easy to get channel resource, and the packet in forwarding queue seldom, almost can not find the packet that can be encoded to together; Along with offered load increases, forwarding queue starts to pile up packet, has occurred that many two packets can be encoded to situation together, that is to say that code machine can increase; But the total amount that can be encoded to packet together accounts for receives that the ratio of packet is not to increase always, when offered load reaches a very high value, data flow complexity levels off to a constant, this constant with the network bandwidth with dispose relevant.That is to say, when offered load is very high, the factor that affects data flow complexity is mainly the complexity of data flow in network.Therefore, we pass through to observe, when
during <0.08, only may have two kinds of situations to occur: the one, node and neighbours thereof are operated under low loading condition, and forwarding queue is empty substantially; The 2nd, node and neighbours thereof are for some special applications such as FTP, Streaming Media provide service, and in network, the complexity of data flow is lower, is unidirectional substantially.In order to reduce algorithm complexity, we are defined as 0.08 by ξ.
Experiment two: the impact of research θ on code machine meeting quantity;
Step 1, the initialization of emulation experiment scene:
It is 1400m that applicant simulates a length, and the wireless mesh network that width is 600m is wherein arranged 86 nodes.In this experiment, the communication radius of each node is 175m, and the link transmission success rate between node is recorded by physical environment.Each experiment simulation duration is 5s, ω packet of each node generation per second, and destination address is selected at random, and the length of each packet is 1000B, and link bandwidth is 54Mbps, and network layer is used minimum hop to count route, by ω, controls offered load.
Step 2, gets θ=0.25s, 0.50s, and 0.75s, 1.00s, gets ω=10, and 20,30,40,50,100,150,200,250,300, altogether carried out 4 * 10 groups of assessments.In order to guarantee the authenticity of experimental result, 1000 experiments have been carried out in every group of assessment, get the desired value of result as every group of final result.
Step 3, analyze and process experimental data:
Fig. 9 shows under different θ, and code machine can situation of change.The different ω values of not collinear representative in figure.From experimental result, can find out: (1), when ω <50, code machine can increase and change with θ hardly; (2), when ω >50, code machine can increase with θ.These two observed result explanations, when offered load hour, even if θ is large again, also there will not be more code machine meeting, and main node is easy to apply for that the data that will forward to channel send; When offered load is large, along with θ increases, code machine can increase gradually, and the growth trend under different loads is basically identical, and this increases acceleration has data flow complexity to determine.In addition, in Fig. 9, below the vertical range of 6 lines is larger, much larger than the vertical range of 4 lines above, illustrate that the impact that network complexity understands code machine is larger.This conclusion of finally obtaining of experiment is, θ on code machine can the impact ω that is far from large because can not θ be established very greatly in order to obtain more odd encoder chance.
Experiment three: the impact that research θ takies nodal cache, and θ's is definite;
Step 1, the initialization of emulation experiment scene:
It is 1400m that applicant simulates a length, and the wireless mesh network that width is 600m is wherein arranged 86 nodes.In this experiment, the communication radius of each node is 175m, and the link transmission success rate between node is recorded by physical environment.Each experiment simulation duration is 5s, ω packet of each node generation per second, and destination address is selected at random, and the length of each packet is 1000B, and link bandwidth is 54Mbps, and network layer is used minimum hop to count route, by ω, controls offered load.The buffer memory of each node is allocated as follows: forwarding queue length does not limit, decode resources queue length 400, if decode resources queue is finished using, separately having length is that 500 emergent queue is for depositing decode resources, recovery queue takies with decode resources queue service condition and has correlation, does not discuss.
Step 2, gets θ from 0.1s to 1.0s, and leapfrog is 0.1s, gets ω from 50 to 300, and leapfrog is 50, has altogether carried out 10 * 6 groups of assessments.In order to guarantee the authenticity of experimental result, 1000 experiments have been carried out in every group of assessment, get the desired value of result as every group of final result.
Step 3, analyze and process experimental data:
Figure 10 (a-d) shows under identical ω, different θ, resource queue's service condition.In figure, difformity point represents the node of different consumption level: square node resource consumption is serious, not only consumes Gan Liao resource queue, also employs emergent queue; Circular node resource is used normal; Rhombus node resource is used on the low side, and utilance is low.From experimental result, can find out: (1) θ hour, be not fully used by the resource queue of most nodes; (2), when θ is larger, although the resource queue of most nodes is fully used, the node that Dan Jiang resource queue exhausts also has a lot.
Figure 11 (a-d) shows under different ω, the impact of θ on three kinds of node proportions.From experimental result, can find out: (1) at offered load hour, along with θ increases, the distribution proportion of three kinds of nodes remains unchanged substantially; (2) at offered load during in middle reaches, compare the light situation of load, the node that Buffer Utilization is low significantly reduces, all convert normal node to, but simultaneously, under this intermediate part load, along with θ increases, understand some normal node and convert red ill node to, when θ >0.3s, this variation is obvious especially; (3) when offered load is higher, the low node of Buffer Utilization still less, but the quantity of this node also starts to receive the impact of θ, and, the quantity of morbid state node is instead than few under intermediate part load, this is that data volume can be dispersed in wider scope due under high load condition, rather than to a part of node, collects fast.
These observed result explanations, in the situation that offered load is lower, θ does not almost affect the service condition of buffer memory, this is deployment and the link-quality of network that affects the principal element of Buffer Utilization, when offered load is higher, the selection of θ can bring two major effects, and the one, affect the quantity of poor efficiency node, the 2nd, the quantity of the ill node of impact.From this experiment, the result finally obtaining is, wants to increase Buffer Utilization, controls ill node in the scope of standing simultaneously, and θ gets 0.3s.
Three, the contrast experiment of the inventive method and additive method
Getting off, we test to verify that by one group the inventive method is with respect to the advantage of other agreements.Experiment mainly compares the performance of following three kinds of algorithms:
(1) FSNC: the i.e. method that the present invention proposes.
(2) CSMA/CA: this agreement is the maximum media access control methods of 802.11 uses, is used RTS-CTS mechanism to conflict and avoids, and there is no reliable broadcast module, there is no encoding mechanism.
(3) XORs: the method classical case that to be first combine network code and practical application is also the maximum method of studied discussion.The method proposing from the present invention is different, and XORs is placed on network code mechanism between media access control layer and TCP layer, and two levels are not all made to modification.
In these experiments, we have used this concept of information throughput to do measurement index, its implication is: in the unit interval, the information content sum of the packet that all nodes of the whole network send, information content wherein, while referring to coding, participating in the also number of the packet of exclusive disjunction, is not 1 through coded data package informatin content perseverance.Experiment mainly proves advantage of the present invention from following several respects:
1. the impact of offered load on protocol capabilities, the 2. impact of link transmission success rate on protocol capabilities, the impact that 3. offered load utilizes buffer memory.
(1) impact of offered load on protocol capabilities:
Artificial network initialization:
It is 1400m that applicant simulates a length, and the wireless mesh network that width is 600m is wherein arranged 86 nodes.In this experiment, the communication radius of each node is 175m, and the link transmission success rate between node is recorded by physical environment.Each experiment simulation duration is 5s, ω packet of each node generation per second, and destination address is selected at random, and the length of each packet is 1000B, and link bandwidth is 54Mbps, and network layer is used minimum hop to count route, by ω, controls offered load.According to result of the test before, we setup parameter θ is 0.3s, and ξ is 0.08.
Emulation experiment process:
In this experiment, get ω=10,20,30,40,50,100,150,200,250,300, altogether carried out 10 groups of assessments.In order to guarantee experimental result authenticity, for each method, 1000 tests have been carried out in every group of assessment, get the desired value of result as every group of final result.
Experimental result:
Figure 12 (a, b) shows the relation in the middle of each agreement the whole network multi-to-multi throughput and offered load ω.As can be seen from the figure, along with offered load increases, do not have the throughput of the CSMA/CA of encoding mechanism to increase then and tend to be steady gradually, this is that channel width is depleted because offered load is when higher, and the whole network is handled up can infinitely not increased down; FSNC compares CSMA/CA obvious throughput hoisting, substantially maintains more than 7%, when, can reach 40%; Offered load is between 50 to 100 time, and the throughput of XORs will be higher than FSNC, and this is that main difference is to have used chance to intercept, and according to ETX route chi, carries out neighbor state prediction because XORs compares with FSNC, by a plurality of packet encoders to together.But in the lower and higher situation of load, the throughput of XORs is not as FSNC, this be because, when load is lower, XORs finds less than thereby a plurality of packet encoders are abandoned to coding to chance together, when load is higher, there is part of nodes once by a plurality of data packet codings together, be broadcast to more multi-object, but because XORs has also clearly been used reliable Radio Broadcasting Agreements, when this just causes broadcast code bag, request channel is very difficult, often because some node channel busy are cancelled whole broadcasting process; In addition, at the packet of large information capacity, during in broadcast, the neighbours of all receiving nodes can not use channel, have so just caused that channel resource utilance is low in larger scope, thereby have affected the whole network throughput.This description of test, FSNC has higher handling up than CSMA/CA, has better adaptability than XORs simultaneously, can adapt to multiple network load.
(2) impact of link transmission success rate on protocol capabilities:
Artificial network initialization:
It is 1400m that applicant simulates a length, and the wireless mesh network that width is 600m is wherein arranged 86 nodes.In this experiment, the communication radius of each node is 175m, each experiment simulation duration is 5s, ω packet of each node generation per second, destination address is selected at random, and the length of each packet is 1000B, and link bandwidth is 54Mbps, network layer is used minimum hop to count route, by ω, controls offered load.According to result of the test before, we setup parameter θ is 0.3s, and ξ is 0.08.
Emulation experiment process:
In this experiment, get ω=100,300, to use at random and generate, the link transmission success rate that meets Gaussian Profile replaces the actual link transmission success rate recording, and Gaussian Profile desired value gets 1 to 0.8, and leapfrog is 0.02.Altogether carried out 2 groups of assessments, in order to guarantee experimental result authenticity, for each agreement, 1000 tests have been carried out in every group of assessment, get the desired value of result as every group of final result.
Experimental result:
Figure 13 (a, b) shows under intermediate part load and high load condition, the relation between each agreement the whole network multi-to-multi throughput and link transmission success rate.As can be seen from the figure, in intermediate part load situation, along with channel circumstance variation, CSMA/CA and FSNC need to pay the mistake bag packet loss phenomenon that extra information throughput brings to overcome channel circumstance, and XORs is in the situation that channel circumstance is good, there is higher throughput, because at this be, the result that neighbours' forecast model of XORs draws is all correct very at high proportion, but along with channel circumstance variation, the forecast model accuracy of XORs starts to reduce, and a lot of encoded packets can not be successfully decoded, and throughput starts to approach to FSNC.Under high load condition, handling up of XORs and CSMA/CA is very approaching, and this is during due to XORs broadcast high information quantity encoded packets, and the neighbours of all receiving nodes, by as for silent status, cause regional channel utilization low, thereby affected the whole network, handle up; And the variation of handling up hardly with link-quality of these two kinds of agreements changes, this is because load is when high, and channel can not provide extra bandwidth for data packet retransmission.Now, FSNC is still keeping 7% the lifting of handling up.This description of test, the performance of FSNC is subject to the impact of link transmission success rate less, and robustness is stronger.
(3) impact that offered load utilizes buffer memory:
Artificial network initialization:
It is 1400m that applicant simulates a length, and the wireless mesh network that width is 600m is wherein arranged 86 nodes.In this experiment, the communication radius of each node is 175m, and the link transmission success rate between node is recorded by physical environment.Each experiment simulation duration is 5s, ω packet of each node generation per second, and destination address is selected at random, and the length of each packet is 1000B, and link bandwidth is 54Mbps, and network layer is used minimum hop to count route, by ω, controls offered load.According to result of the test before, we setup parameter θ is 0.3s, and ξ is 0.08.
Emulation experiment process:
In this experiment, get ω=60,100,200,300, altogether carried out 4 groups of assessments, in order to guarantee experimental result authenticity, for each agreement, 1000 tests have been carried out in every group of assessment, get the desired value of result as every group of final result.
Experimental result:
Figure 14 (a-d) shows XORs and the use of two kinds of method decode resources buffer queues of FSNC and the relation of offered load.As can be seen from the figure, under diverse network load, the buffer memory use amount of XORs node is all high than FSNC, some situation even exceeds several times, this is because the XORs node data that not only buffer memory self forwarded, the data of the neighbor node that also buffer memory chance listens to, and the good cache management mechanism of neither one.In addition, XORs point distributes more extensive than FSNC point, and FSNC point is more concentrated, means that the buffer memory usage variance of XORs is larger, method less stable, and to the more difficult control of the distribution of buffer memory, by contrast, FSNC is more stable, also more easily controls.
Claims (5)
1. the wireless mesh network media access control method of a coding Network Based, it is characterized in that, in this wireless mesh network, when a node, receive after the packet that neighbor node sends, judge that this packet is general data bag or coded data packet:
If coded data packet is decoded to this coded data packet, successfully decoded obtains the general data bag needing, unsuccessful this coded data packet that abandons of decoding;
If general data bag judges whether this general data bag reaches the formation condition of coded data packet, as reached, it is encoded, and the coded data packet obtaining after coding is broadcasted to neighbor node; As do not reached formation condition, this general data bag is forwarded according to 802.11 agreements;
Formation condition and the cataloged procedure of coded data packet are as follows:
In this wireless mesh network, node A has two neighbor nodes at least, if the forwarding queue of initial time node A is empty, from initial time, start: node A receives the general data bag p2 that neighbor node sends, in forwarding queue, find a general data bag p1, if exist p1 to meet formula 1 and formula 2 simultaneously, p1 and p2 coding are become to coded data packet p;
In formula 1, s1, s2 are respectively the source node MAC Address of packet p1, p2, and d1, d2 are respectively the MAC Address of p1, p2 next-hop node, and t1, t2 are respectively the time that p1, p2 reach node A, and θ value is 0.3 second;
In formula 2, r and c are respectively node A from initial time, receive in the accumulative total number of general data bag and the forwarding queue of node A that neighbor node sends, meet the accumulative total number of the general data bag of formula 1, wherein r at every turn cumulative 1, c at every turn cumulative 2, ξ value be 0.08.
2. the wireless mesh network media access control method of coding Network Based as claimed in claim 1, is characterized in that, described general data bag p1 and p2 become coded data packet p through also exclusive disjunction coding, are specially:
General data bag p2 destination host MAC Address and p1 destination host MAC Address are done to also exclusive disjunction, and acquired results is inserted the destination host MAC field of p1; General data bag p2 source host MAC Address and p1 source host MAC Address are done to also exclusive disjunction, and acquired results is inserted the source host MAC field of p1; The data division of the data division of p2 and p1 is done to also exclusive disjunction, and acquired results is inserted the data division field of p1; If the data division length of p1 and p2 is inconsistent, 0 cover is filled out to by the shorter square tail portion of length, the new packet of generation is coded data packet p.
3. the wireless mesh network media access control method of coding Network Based as claimed in claim 1, it is characterized in that, in this wireless mesh network, in each node, be provided with resource queue, when being bundled into merit by a general data, node sends to after another node, this general data bag is moved into resource queue from forwarding queue, and be that this general data bag starts a count-down device, count-down device initial value is θ, after count-down device makes zero, this general data Bao Cong resource queue is removed.
4. the wireless mesh network media access control method of coding Network Based as claimed in claim 3, it is characterized in that, when node is received after a coded data packet, it is carried out to decode operation: node is found the general data bag corresponding with the coded data packet of receiving from the resource queue of oneself, the general data bag finding and the coded data packet of receiving are carried out to also exclusive disjunction, obtain the general data bag needing.
5. the wireless mesh network media access control method of coding Network Based as claimed in claim 1, is characterized in that, described node A generates after coded data packet p, and the step that p is broadcasted is as follows:
Step S1, creates broadcast RTS frame, the MAC Address of the next-hop node of general data bag p1, p2 write in RTS frame, and definite channel occupancy duration Tb, the call duration time field of Tb being added to broadcast RTS frame, Tb computational methods are as follows:
Tb=5 * SIFS+ (82+L) * t
0(formula 3)
In formula 3, SIFS is the shortest stand-by period constant of 802.11 agreement regulations, and L is the length of coded data packet p, t
0for transmitting a needed time of byte, by link bandwidth, determined;
Step S2, node A broadcast RTS frame request channel;
Step S3, neighbor node is received after RTS frame, determines and oneself replys the stand-by period Tcts of RTS frame, and after the stand-by period, reply CTS frame to node A; Tcts computational methods are as follows:
In formula 4, the MAC Address that iMAC is this neighbor node, d1, d2 are respectively the MAC Address of the next-hop node of packet p1, p2;
Step S4, node A sends broadcast RTS frame, waits for 2 * SIFS+28 * t
0after time, check the CTS frame condition of receiving, if receive respectively the CTS frame that the next-hop node of p1, p2 is replied, node A waits for that SIFS starts after the time to send coded data packet p, otherwise node A enters back-off wait.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201410216133.2A CN103957085B (en) | 2014-05-21 | 2014-05-21 | Media access control method for wireless mesh network based on network coding |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201410216133.2A CN103957085B (en) | 2014-05-21 | 2014-05-21 | Media access control method for wireless mesh network based on network coding |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN103957085A true CN103957085A (en) | 2014-07-30 |
| CN103957085B CN103957085B (en) | 2017-02-15 |
Family
ID=51334319
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201410216133.2A Expired - Fee Related CN103957085B (en) | 2014-05-21 | 2014-05-21 | Media access control method for wireless mesh network based on network coding |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN103957085B (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107294807A (en) * | 2017-07-04 | 2017-10-24 | 中国联合网络通信集团有限公司 | Protocol interoperability method of testing and device |
| CN111327707A (en) * | 2020-03-05 | 2020-06-23 | 重庆邮电大学 | Cache replacement method based on network coding in wireless network |
| CN112584460A (en) * | 2020-12-09 | 2021-03-30 | 重庆邮电大学 | Opportunistic routing method based on network coding in wireless network |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20080247407A1 (en) * | 2007-04-04 | 2008-10-09 | Nokia Corporation | Combined scheduling and network coding for wireless mesh networks |
| CN101611598A (en) * | 2007-03-08 | 2009-12-23 | 英特尔公司 | For two-way relaying makes up grouping in physical layer |
| EP2216954A1 (en) * | 2009-02-10 | 2010-08-11 | Fujitsu Limited | Data relay apparatus, communication apparatus and communication method |
| CN101888358A (en) * | 2010-07-15 | 2010-11-17 | 华中科技大学 | Transmission method for reducing computational complexity of two-way relay nodes based on network coding |
-
2014
- 2014-05-21 CN CN201410216133.2A patent/CN103957085B/en not_active Expired - Fee Related
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101611598A (en) * | 2007-03-08 | 2009-12-23 | 英特尔公司 | For two-way relaying makes up grouping in physical layer |
| US20080247407A1 (en) * | 2007-04-04 | 2008-10-09 | Nokia Corporation | Combined scheduling and network coding for wireless mesh networks |
| EP2216954A1 (en) * | 2009-02-10 | 2010-08-11 | Fujitsu Limited | Data relay apparatus, communication apparatus and communication method |
| CN101888358A (en) * | 2010-07-15 | 2010-11-17 | 华中科技大学 | Transmission method for reducing computational complexity of two-way relay nodes based on network coding |
Non-Patent Citations (2)
| Title |
|---|
| 王龙翔: ""基于网络编码的MAC协议研究"", 《中国优秀硕士论文全文数据库》 * |
| 黄勐: ""无线多跳网络中基于网络编码的MAC机制研究"", 《中国优秀硕士学位论文全文数据库》 * |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107294807A (en) * | 2017-07-04 | 2017-10-24 | 中国联合网络通信集团有限公司 | Protocol interoperability method of testing and device |
| CN111327707A (en) * | 2020-03-05 | 2020-06-23 | 重庆邮电大学 | Cache replacement method based on network coding in wireless network |
| CN111327707B (en) * | 2020-03-05 | 2022-04-05 | 重庆邮电大学 | Cache replacement method based on network coding in wireless network |
| CN112584460A (en) * | 2020-12-09 | 2021-03-30 | 重庆邮电大学 | Opportunistic routing method based on network coding in wireless network |
| CN112584460B (en) * | 2020-12-09 | 2022-06-03 | 重庆邮电大学 | Opportunistic routing selection method based on network coding in wireless network |
Also Published As
| Publication number | Publication date |
|---|---|
| CN103957085B (en) | 2017-02-15 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN109995515B (en) | Quantum key relay method | |
| Zhuo et al. | Contact duration aware data replication in delay tolerant networks | |
| CA2854599C (en) | Routing communications based on link quality | |
| CA2854636C (en) | Routing communications based on node availability | |
| CN102273176A (en) | System and method for retransmission and fragmentation in a communication network | |
| US7996534B2 (en) | File distribution in wireless networks | |
| CN108696449A (en) | A kind of data dispatching method and device | |
| CN103957085A (en) | Media access control method for wireless mesh network based on network coding | |
| US20140321384A1 (en) | Data broadcasting with a prepare-to-broadcast message | |
| CN104243098A (en) | Transmitting method based on parallel batch network coding | |
| CN103188054B (en) | The acquisition methods of feedback delay, Apparatus and system | |
| He et al. | Greedy construction of load‐balanced virtual backbones in wireless sensor networks | |
| WO2015106444A1 (en) | Transmission method and transmission device for data packet | |
| CN103402233B (en) | Based on the high throughput wireless distributed network method for routing of serial interference elimination | |
| CN103634846A (en) | Method employing greedy algorithm to distribute channel resource in multichannel multi-hop wireless network | |
| Chlebus et al. | Energy efficient adversarial routing in shared channels | |
| JP2016201833A (en) | Data broadcast with prepare-to-broadcast message | |
| Yu et al. | PYRAMID: Informed content reconciliation for vehicular peer-to-peer systems | |
| Chhaya et al. | Cross layer optimization and simulation of smart grid home area network | |
| CN103002017B (en) | A kind of method of Gains resources, equipment and system | |
| CN104811720A (en) | Video IPB frame transmission mapping mechanism realization method based on Mesh network | |
| Wu et al. | A chain-based fast data aggregation algorithm based on suppositional cells for wireless sensor networks | |
| Zhou et al. | Performance analysis of network coded cooperative D2D communications | |
| Conde et al. | Content Distribution Optimization Algorithms in Vehicular Networks | |
| Narayana et al. | Using WAN Aggrandizement explication to remove defects in TCP performance in AD-Hoc network |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C06 | Publication | ||
| PB01 | Publication | ||
| C10 | Entry into substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20170215 |
|
| CF01 | Termination of patent right due to non-payment of annual fee |