CN106533941A - Compressed sensing theory based low-jitter coding awareness routing method - Google Patents

Abstract

The invention discloses a compressed sensing theory based low-jitter coding awareness routing method, and belongs to the field of wireless network. The compressed sensing theory based low-jitter coding awareness routing method is invented to mainly solve the problem in the prior art that data packet jitter performances at various rates cannot be improved efficiently in the presence of network congestion. The technical scheme comprises the steps of 1, carrying out coding awareness routing discovery in a network, and finding coding nodes and a coding path by adopting routing measurement of routing hops which gives consideration to a coding opportunity; 2, carrying out network jitter training for the found coding nodes on the path by using a queue length based cache management strategy so as to realize selection of an optimal threshold value; and 3, adopting a corresponding queue length based decision-making strategy for received data packets by the coding nodes based on a given optimal threshold value. Compared with the prior art, the compressed sensing theory based low-jitter coding awareness routing method can improve various network performances including the data packet jitter at various rates efficiently in the presence of the network congestion.

Description

Low jitter coding perception route method based on compressive sensing theory

Technical field

The invention belongs to field of wireless, is related to a kind of method for routing of backbone network, can be used for various speed scenes Under wireless multimedia service.

Background technology

In recent years, with the fast development of radio network technique, wireless multimedia service is also into people's daily life With the every field of work, multimedia service occupies increasingly consequence in network communications.Some multimedia services have The demand of the aspects such as data package jitter, this design to wireless network proposes new demand.Data package jitter is internetworking One of important indicator of energy, it is particularly important to multimedia application.

Compared with traditional store-and-forward mode, network code can make full use of the broadcast characteristic of wireless channel, by original The unicast transmission of the multiple raw data packets come is changed into the broadcast transmission of first encoding packet, and is not take up extra channel Capacity, so as to reduce data transmission times, has postponed the generation of channel congestion, reduces the purpose of data package jitter.

So-called network code perception route, be exactly route metric in the route discovery stage add " network code " because Element, guiding data flow is towards the path transmission that can increase network coding opportunity.However, existing coding perception route agreement is adopted It is the network code strategy based on chance, does not account for the buffer status of coding nodes, the forwarding of packet will not be postponed To wait the code machine meeting in future.This way can lose some potential code machine meetings, reduce network code to packet The contribution of shake.In the case of network congestion, it is considered to the needs of multimedia service, the data package jitter for reducing wireless network has Important meaning.

Analyze based on more than, the jitter of coding perception route if making full use of code cache state, can be improved Can, further reduce data package jitter.In the case of considering code cache state in data packet coding, existing coding nodes In cache management strategy, get up fairly simple based on the strategy implement of queue length, if the queue length of caching is more than one Threshold value, packet will be by codeless forwardings.But if it is improper that threshold value is chosen, the shake of packet may be larger.

The concept of compressed sensing (Compressed Sensing, CS) is that Donoho and Candes et al. in 2006 are proposed , the linear projection that primary signal is actually completed from higher dimensional space to lower dimensional space using calculation matrix by it obtains few Projection value of the amount comprising primary signal full detail, then make use of the openness/compressibility reality of signal in algorithm for reconstructing The high probability Exact Reconstruction of primary signal is showed.Different from the signal sampling of Nyquist, CS is that original signal information is adopted Sample, the data of sampling only those contain the data of signal of interest information.

In order to Exact recovery primary signal, the sampling process of CS must assure that the information for not destroying primary signal, i.e., Ensure that the measured value after projection possesses the full detail of primary signal.In the case where network transmission reaches and stablizes, sub-fraction The network performance that packet is characterized possesses the information of the longer-term network performance that all packets are characterized.The theoretical thoughts of CS are used for reference, In the case where network reaches and stablizes, the network performance that sub-fraction packet is characterized can just reflect all numbers of network transmission According to the longer-term network performance that bag is characterized.

Therefore, how coding perception routing algorithm and buffer storage managing algorithm are combined based on compressive sensing theory, is given full play to Its advantage improves the jitter performance of network in the case of network congestion to implement a kind of simple, effective method for routing, is one Individual good problem to study.

The content of the invention

For the problems referred to above, the present invention proposes a kind of low jitter coding perception route side based on compressive sensing theory Method, in coding nodes using the packet decision strategy based on queue length, devises the number that can characterize network jitter performance According to bag tolerance AVPWD (Average Variation in Packet Waiting Delay), and the theoretical thoughts of CS are used for reference, Its long-term jitter performance is reflected with the AVPWD of data flow small part packet, network was introduced before data transfer phase and is trembled The dynamic training stage, coding nodes are made to obtain the optimal threshold based on queue length strategy.In view of PACKET RECEIVE SEQUENCE pair Impact of the packet number in the impact and coding queue of network jitter performance to code machine meeting, based on queue length strategy Threshold search scope the upper bound and Nonzero Lower Bounds be respectively set as min (K-1,11) He 5, here K for coding nodes queue Length.The inventive method can in the case of network congestion, lifted under various speed scenes including including data package jitter Every network performance.

For achieving the above object, the present invention is employed the following technical solutions, and a kind of low jitter based on compressive sensing theory is compiled Code perception route method, comprises the steps：

(1) carry out in a network encoding perception route discovery, according to coding opportunity information and hop count information acquisition road By measuring, and coding nodes and path are chosen according to route metric；

(2) coding nodes on the path that searches out in step (1) are entered with the cache management strategy based on queue length The following network jitter training of row, realizes the selection of optimal threshold：

2a) setting characterizes the packet average waiting delay change of each threshold value i of multimedia service dither flow performance For：

Wherein, AVPWD changes for packet average waiting delay, i ∈ { 0 } ∪ [5, min (11, K-1)], and K is coding section The queue length of point, p_ijIt is coding nodes correspondence threshold value i and multimedia service stream j-th of Successful transmissions in the sampling interval t Packet, B (p_ij) and A (p_ij) packet p is represented respectively_ijCoding queue in go out group time and queuing time, M_iFor coding The packet number of the node correspondence threshold value i and multimedia service stream Successful transmissions in the sampling interval t；

Threshold value i is initialized as into 0 2b), source node sends packet according to the path for searching out, and coding nodes are with based on team The cache management strategy of row length is effectively transmitted or is waited to the packet from different data streams, steady in data transfer Regularly, in a fixed sampling interval t, each packet p of the Successful transmissions of coding nodes record multimedia service stream_0j Queuing time A (p in coding queue_0j) and go out group time B (p_0j), and count the Successful transmissions of multimedia service stream Number M of packet₀Afterwards, according to step 2a) in formula be calculated AVPWD (0)；

2c) threshold value i is increased as 5, in a fixed sampling interval t, coding nodes record multimedia service stream Each packet p of Successful transmissions_5jQueuing time A (p in coding queue_5j) and go out group time B (p_5j), and count many Number M of the packet of the Successful transmissions of media business stream₅Afterwards, according to step 2a) in formula be calculated AVPWD (5)；

2d) by threshold value i in step 2c) on the basis of be incremented by every time 1, by step 2c) it is same in the way of, coding nodes are obtained Packet average waiting delay change AVPWD (6) of correspondence threshold value i in the t of interval, AVPWD (7) ..., AVPWD (min (K-1, 11))；

2e) from AVPWD obtained above (0), AVPWD (5) ..., packet is found out in AVPWD (min (K-1,11)) and is put down Corresponding threshold value when waiting Delay Variation numerical value minimum, using the threshold value as optimal threshold；

(3) coding nodes are long using queue is based on to the packet for receiving according to the optimal threshold chosen in step (2) The decision strategy of degree carries out coding forwarding, directly forwarding or wait.

The present invention has advantages below compared with prior art：

1st, the present invention substitutes existing base using packet decision strategy effectively based on queue length in coding nodes In the network code strategy of chance, code cache state is taken full advantage of, overcome traditional network code plan based on chance The deficiency of following code machine meeting can not be slightly waited, network jitter performance is optimized；

2nd, the present invention devises packet tolerance AVPWD, and which can characterize the jitter performance of network；

3rd, the present invention uses for reference the theoretical thoughts of CS, reflects its long-term jitter with the AVPWD of data flow small part packet Can, the network jitter training stage is introduced before data transfer phase, coding nodes is obtained based on queue length strategy Optimal threshold, overcome the negative effect for being generally basede on that queue length strategy may be caused to data package jitter performance, effectively The data package jitter performance improved under network congestion.

Description of the drawings

Fig. 1 be the present invention realize general flow chart；

Fig. 2 is the schematic diagram of the backbone network that present invention emulation is used；

Fig. 3 for etc. in the case of speed, the network performance comparison diagram of distinct methods；

In the case that Fig. 4 is the change of all streaming rates, the network performance comparison diagram of distinct methods；

In the case that Fig. 5 is the change of an only data flow velocity rate, the network performance comparison diagram of distinct methods.

Specific embodiment

Describe the present invention referring to the drawings.

With reference to Fig. 1, the low jitter coding perception route method based on compressive sensing theory of the present invention, including following step Suddenly：

Step 1：Carry out in a network encoding perception route discovery, according to coding opportunity information and hop count acquisition of information Route metric, finds coding nodes and path with this；The route metric of the present invention is used for weighing hop count information and code machine Can information.

1a) source node n_srcTo its neighbor node broadcast route request packet RREQ, the RREQ bags are in original plane on demand Routing information item path_addr is increased on the RREQ package bases of distance vector routing protocol AODV, path_addr have recorded this The node experienced by path；

1b) when intermediate node receives a RREQ bag, first check whether to have received the RREQ bags, if It is then to abandon the RREQ bags to avoid the formation of loop, execution step 1c)；If it is not, then intermediate node will be updated in RREQ Routing information path_addr, oneself will be added on the path that the data flow is passed through, and broadcasts this RREQ bag；

1c) when RREQ is coated with destination node n_dstWhen receiving, destination node n_dstWill be to source node n_srcRoute is sent reversely Reply data bag RREP, the RREP bags are a unicast packets, contain source node n_srcTo destination node n_dstRequired road Coding opportunity information n (p) of footpath information p and path p, wherein n (p) represent that the code machine of path p can number；

1d) when intermediate node receives RREP bags, that is, obtain the routing information p of new route, intermediate node is according to obtaining The routing information for obtaining judges whether oneself can be encoded：

If the node preserves the routing information of other data flows for flowing through, and the path and new route p are in the middle of this Node it is upper and lower one jump in the range of exist overlap, then the intermediate node in RREP the vertex ticks be " can encode ", together Shi Gengxin n (p) items；

1e) as source node n_srcAfter receiving multiple RREP bags, source node n_srcWill be potential according to what is included in these RREP bags Code machine can n (p) calculating R_NCP ()=HopCount (p)-n (p), selects R_NC(p) minimum path p_lAnd start to send data Bag, into the network jitter training stage, wherein HopCount (p) represents the hop count of path p；

1f) after first packet reaches intermediate node, the intermediate node will preserve the path of selected new route Information p_l, and continue to forward the packet.

Step 2：Coding nodes on the path that searches out are carried out with the cache management strategy based on queue length as follows Network jitter is trained, and realizes the selection of optimal threshold.

2a) for the packet decision strategy based on queue length of coding nodes, setting characterizes multimedia service stream and trembles The packet average waiting delay of each threshold value i of dynamic performance changes AVPWD：

Here i ∈ { 0 } ∪ [5, min (11, K-1)], queue lengths of the K for coding nodes, p_ijFor coding nodes correspondence threshold J-th packet of the value i and multimedia service stream Successful transmissions in the sampling interval t, B (p_ij) and A (p_ij) data are represented respectively Bag p_ijCoding queue in go out group time and queuing time, M_iIt is that coding nodes correspondence threshold value i and multimedia service stream are being adopted The packet number of Successful transmissions in the t of sample interval；

Threshold value i is initialized as into 0 2b), source node sends packet along selected path, and coding nodes are with based on queue The cache management mode of length strategy is effectively transmitted or is waited to the packet from different data streams, in data transfer When stable, in a fixed sampling interval t, each packet of the Successful transmissions corresponding to multimedia service stream is recorded p_0jFor the queuing time A (p in code cache queue_0j) and go out group time B (p_0j), and count corresponding to multimedia service stream Successful transmissions packet number M₀, it is calculated AVPWD (0)；

It is 5 2c) to increase threshold value i, and in a fixed sampling interval t, coding nodes are recorded corresponding to multimedia Each packet p of the Successful transmissions of Business Stream_5jA (p_5j) and B (p_5j), and count the success corresponding to multimedia service stream Number M of transmission packet₅, according to 2a) formula be calculated AVPWD (5), and while make threshold value i add 1, the above-mentioned mistake of repetition Journey, node can obtain correspondence threshold value i interval t in numerical value AVPWD (6), AVPWD (7) ..., AVPWD (min (K-1, 11))；

2d) from AVPWD obtained above (0), AVPWD (5) ..., numerical value is found out in AVPWD (min (K-1,11)) minimum When corresponding threshold value, using the threshold value as optimum threshold value.

Step 3：Coding nodes are according to the optimal threshold selected to the packet for receiving using determining based on queue length Plan strategy carries out coding forwarding, directly forwarding or wait.

Setting L^*The optimal threshold based on queue length strategy obtained by network jitter training stage coding nodes.

3a) coding nodes are judged to the packet for receiving, and judge that the packet is coding bag or original packet；

If the packet is coding wrapped, whether have in checking decoding caching for decoding the remainder data that this coding is wrapped Stream information, if it is not, abandoning the coding bag, process ends；If it has, then isolating the original of the data flow of needs Bag, execution step 3b)；

If the packet is original packet, execution step 3b)；

3b) check whether the coding nodes have the packet on matching flow path to reach, if it has, then to carrying out Self Matching stream The packet in path carries out coding forwarding, process ends；If it is not, the coding nodes are inserted it in code cache Then the length of the buffer queue is checked, L, execution step 3c is set to)；

If 3c) L is more than L^*, then directly otherwise, waited in coding queue without coding forwarding.

The effect of the present invention can be further illustrated by following experiment：

1st, experiment condition and content：

NS2.35 network simulation platforms are adopted in experiment, the com-parison and analysis in wireless backbone network topology as shown in Figure 2 Based on the inventive method and two kinds of coding perception routes of the network code strategy based on chance in the case of network congestion Every network performance of algorithm, the performance change of wherein data package jitter are directed to data flow 1, devise a kind of wireless backbone Network, as shown in Fig. 2 DCF mechanism of the mac-layer protocol using IEEE802.11, double-wave model is obeyed in signal attenuation, using UDP Data source, buffer queue size are 50 packets, and the network jitter training interior joint sampling interval is using empirical value 0.4s.

Two data streams, respectively data flow 1 and data flow 2 are there are in the network of emulation, wherein data flow 1 is spy Fixed multimedia service stream, its source node is 1, and destination node is 4；The source node of data flow 2 is 4, and destination node is 3.This Network code method for routing in bright is defined as BLJCAR, the coding perception route of the traditional network code strategy based on chance Method is defined as ONC.

2nd, emulation experiment and result：

Experiment one：In this simulated environment, data flow 1 and both speed of data flow 2 are equal and be 280～560kbps.Figure 3 (a), Fig. 3 (b), Fig. 3 (c) and Fig. 3 (d) respectively illustrate above-mentioned 2 kinds of algorithms under this scene average data packet jitter change, Network throughput change, the change of average end-to-end time delay and bursts dropping ratio change.

Fig. 3 shows that the inventive method is in average data packet jitter, network throughput, average end-to-end time delay and packet Advantage in terms of Loss Rate is obvious.

Experiment two：In this simulated environment, the speed of data flow 1 is 2 times of 2 speed of data flow, and the speed of data flow 2 For 230～340kbps.Fig. 4 (a), Fig. 4 (b), Fig. 4 (c) and Fig. 4 (d) respectively illustrate corresponding 2 kinds of algorithms under this scene Performance change.

Fig. 4 shows that the inventive method can be lifted including the every net including data package jitter in the case of network congestion Network performance.

Experiment three：In this simulated environment, the speed of data flow 1 is fixed as 300kbps, and the speed of data flow 2 is 300 ～600kbps.Fig. 5 (a), Fig. 5 (b), Fig. 5 (c) and Fig. 5 (d) respectively illustrate the performance of corresponding 2 kinds of algorithms under this scene and become Change.

Fig. 5 shows, the inventive method improves the jitter performance of network, and network throughput, it is average end-to-end when Traditional network code strategy based on chance is better than in terms of prolonging with bursts dropping ratio..

Above three emulation shows that the inventive method can lift the bag under various speed scenes in the case of network congestion Data package jitter is included in interior every network performance.

Presently preferred embodiments of the present invention is the foregoing is only, is not construed as limiting the invention, it is all in the present invention Spirit and principle within, any modification, equivalent substitution and improvements done etc., should be included in protection scope of the present invention it It is interior.

Claims (3)

1. a kind of low jitter based on compressive sensing theory encodes perception route method, it is characterised in that comprise the steps：

(1) carry out in a network encoding perception route discovery, according to coding opportunity information and hop count information acquisition route degree Amount, and coding nodes and path are chosen according to route metric；

(2) coding nodes on the path that searches out in step (1) are carried out with the cache management strategy based on queue length as Lower network shake training, realizes the selection of optimal threshold：

2a) the packet average waiting delay of each threshold value i of setting sign multimedia service dither flow performance becomes and turns to：

$AVPWD\left(i\right)=\frac{1}{M_i-1}\underset{j=1}{\overset{M_i-1}{\Σ}}\[\left(B\right(p_{ij+1})-A(p_{ij+1}\left)\right)-\left(B\right(p_{ij})-A(p_{ij}\left)\right)\]$

Wherein, AVPWD changes for packet average waiting delay, i ∈ { 0 } ∪ [5, min (11, K-1)], and K is coding nodes Queue length, p_ijJ-th data of the Successful transmissions in the sampling interval t for coding nodes correspondence threshold value i and multimedia service stream Bag, B (p_ij) and A (p_ij) packet p is represented respectively_ijCoding queue in go out group time and queuing time, M_iFor coding nodes The packet number of the correspondence threshold value i and multimedia service stream Successful transmissions in the sampling interval t；

Threshold value i is initialized as into 0 2b), source node sends packet according to the path for searching out, coding nodes are long with queue is based on The cache management strategy of degree is effectively transmitted or is waited to the packet from different data streams, stable in data transfer When, in a fixed sampling interval t, each packet p of the Successful transmissions of coding nodes record multimedia service stream_0j Queuing time A (p in coding queue_0j) and go out group time B (p_0j), and count the number of the Successful transmissions of multimedia service stream According to number M of bag₀Afterwards, according to step 2a) in formula be calculated AVPWD (0)；

2c) threshold value i is increased as 5, in a fixed sampling interval t, the success of coding nodes record multimedia service stream Each packet p of transmission_5jQueuing time A (p in coding queue_5j) and go out group time B (p_5j), and count multimedia Number M of the packet of the Successful transmissions of Business Stream₅Afterwards, according to step 2a) in formula be calculated AVPWD (5)；

2d) by threshold value i in step 2c) on the basis of be incremented by every time 1, by step 2c) it is same in the way of, coding nodes obtain correspondence Packet average waiting delay change AVPWD (6) of threshold value i in the t of interval, AVPWD (7) ..., AVPWD (min (K-1, 11))；

2e) from AVPWD obtained above (0), AVPWD (5) ..., packet is found out in AVPWD (min (K-1,11)) averagely etc. Corresponding threshold value when Delay Variation numerical value is minimum, using the threshold value as optimal threshold；

(3) coding nodes according in step (2) choose optimal threshold to the packet for receiving using based on queue length Decision strategy carries out coding forwarding, directly forwarding or wait.

2. the low jitter based on compressive sensing theory according to claim 1 encodes perception route method, it is characterised in that Described in step (1) according to coding opportunity information and hop count information acquisition route metric, and chosen according to route metric Coding nodes and path, specifically include following steps：

1a) source node to its neighbor node broadcast route request packet RREQ, swear in original plan range on demand by the RREQ bags Routing information item path_addr, the routing information item path_ be increased on the basis of the RREQ bags of amount Routing Protocol AODV Addr have recorded the node experienced by the path；

1b) when intermediate node receives route request packet RREQ, first check whether to have received the RREQ bags, such as Fruit is then to abandon the RREQ bags, execution step 1c)；If it is not, then the routing information item path_addr in RREQ bags is updated, Oneself will be added on the path that the data flow is passed through, and broadcast the RREQ bags after updating, execution step 1c)；

1c) when destination node receives the RREQ bags after updating, destination node is to source node singlecast router reply data bag RREP, the RREP bags contain the coding opportunity information of routing information and the routing information needed for source node to destination node；

1d) when intermediate node receives route replies packet RREP, that is, routing information is obtained, intermediate node is according to acquisition Routing information judge whether oneself can be encoded：

If the intermediate node preserves the routing information of other data flows for flowing through, and the routing information and the path letter for obtaining Cease to exist in the range of jumping upper and lower the one of the intermediate node and overlap, then the intermediate node the vertex ticks is in RREP bags " can encode ", while updating coding opportunity information；

1e) after source node receives multiple route replies packet RREP, source node is according to the coding included in these RREP bags Opportunity information and hop count information path selection simultaneously start to send packet；

The path selection, specially：By R_NCP ()=HopCount (p)-n (p) calculates route metric, by degree of route When amount is minimum, corresponding path is used as the path for sending packet；In formula, R_NCP () represents the route metric of path p, HopCount P () represents the hop count information of path p, n (p) represents the coding opportunity information of path p；

1f) after first packet reaches intermediate node, the intermediate node will preserve step 1e) selected in path path Information, and continue to forward the packet.

3. the low jitter based on compressive sensing theory according to claim 2 encodes perception route method, it is characterised in that： The step (3) specifically includes following steps：

3a) coding nodes judge that the packet for receiving is coding bag or original packet；The coding bag is encoded number According to bag, original packet is the packet without coding；

If the packet is coding bag, whether have in checking caching for decoding this remainder data stream information for encoding bag, If it is not, abandoning the coding bag, process ends；If it has, then isolating the original packet of the data flow of needs, step is performed Rapid 3b)；

If the packet is original packet, execution step 3b)；

3b) check whether the coding nodes have the packet on matching flow path to reach, if it has, then to carrying out Self Matching flow path Packet carry out coding forwarding, process ends；If it is not, the coding nodes the original packet separated and without Detached original packet is inserted in code cache, then checks the length of the buffer queue, execution step 3c)；Described matching Flow path refers to the data flow paths traversed that there is code machine meeting in coding nodes, and these data flows match stream each other；

3c) length of buffer queue and optimal threshold are compared, if the length of buffer queue is more than optimal threshold, directly Switch through and send out, otherwise, waited in coding queue.