CN103402233B - Based on the high throughput wireless distributed network method for routing of serial interference elimination - Google Patents

Abstract

The invention discloses a kind of high throughput wireless distributed network method for routing based on serial interference elimination, its implementation procedure is: each node is set up and maintenance of neighbor node table, local information table and interfering link information table; When business arrives, source node broadcasts is by asking bag; Intermediate node receives routing request packet, after calculating the interference level of link and the space resources of consumption, upgrades route requests package informatin and broadcasts; The routing request packet that destination node process receives obtains the route metric in wherein path, i.e. interference level and space resources, then the tolerance by comparing path obtains an optimal path, finally, destination node sends route replies bag to source node, and the routing procedure based on serial interference elimination terminates.The invention solves the problem that the cognitive route entire throughput of traditional interference is low and consumption of network resources is more, significantly improve the entire throughput of multi-hop wireless network, can be used for the routing procedure of multi-hop wireless distributed network.

Description

Based on the high throughput wireless distributed network method for routing of serial interference elimination

Technical field

The invention belongs to radio network technique field, relate generally to multi-hop wireless network method for routing, specifically a kind of high throughput wireless distributed network method for routing based on serial interference elimination, for multi-hop wireless distributed network.

Background technology

Interference is the major influence factors of restriction multi-hop wireless throughput performance.Due to the broadcast characteristic of wireless channel, the wireless signal simultaneously transmitted can disturb mutually, when the interference in network is not effectively controlled, can cause Transmission, network congestion, finally cause the throughput of network significantly to decline.By distributing the mutual interference that different Internet resources (such as time, space, band resource) can be avoided between signal to unlike signal.Therefore, a kind of effective procotol how is designed very important to utilize limited network resources to obtain higher throughput.

Routing Protocol in the end-to-end throughput performance of network and network is closely related.And traditional wireless network route technology does not consider the impact of interference on throughput mostly, use the throughput of the network of this route technology general lower.In Wireless Network Routing Protocol, add interference perceptional factors can make the throughput of network be significantly improved, the overwhelming majority in the cognitive route of existing interference is based on interference avoidance mechanism, namely in routing decision process, the impact of interference on link performance is considered, make selected path avoid interference comparatively serious region as much as possible, thus alleviate the impact of interference on network throughput.But this method for routing has following shortcoming: the first, the method can only passively be avoided disturbing comparatively serious region in network, and it levels off to zero to the gain of network throughput gradually along with the increase in network interferences region; The second, disturb the execution avoided often to increase the resource such as space, bandwidth in the network of routing cost for cost, thus cause the further increase disturbed in network.Under so a kind of background, need a kind of new Interaction Handler system to break the limitation of the cognitive route of existing interference.

In recent years, along with the development of physical-layer techniques, serial interference elimination (SIC) technology obtain investigation and application widely.IEEETransactiononInformationTheory is published in by people such as Weber, document " Transmissioncapacityofwirelessadhocnetworkswithsuccessiv einterferencecancellation " on Vo1.53, No.8Aug.2007 demonstrates the gain of successive interference cancellation techniques to network throughput theoretically.Link receiving terminal can eliminate the impact of a part of interference signal on echo signal by using successive interference cancellation techniques, makes the link of interference mutually originally be transmitted so simultaneously, thus substantially increases the spatial reuse degree of wireless network.In multi-hop wireless network, use successive interference cancellation techniques, the impact of interference on wireless transmission can be alleviated on the one hand, thus reduce necessity that path avoids interference region to a certain extent; The space resources that link transmission consumes can be reduced on the other hand, thus enable network carry more business.Present stage has the chip production that possesses successive interference cancellation techniques and comes into operation, the CSM6850 chip of such as QUALCOMM company, and has relevant MAC layer scheduling protocol in succession to propose.Although use these scheduling protocols based on successive interference cancellation techniques can obtain significant MAC layer gain, be difficult to make the throughput end to end of network also to obtain so large gain by means of only these scheduling protocols.This is because end-to-end throughput depend primarily on Routing Protocol can appropriate design, and the existing Routing Protocol cognitive based on interference does not consider when routing decision the gain that serial interference elimination is brought wireless receiving on the one hand, this can cause route to consume unnecessary Internet resources in order to avoid those interference in fact can eliminated; On the other hand, because receiving terminal uses successive interference cancellation techniques to eliminate interference signal demand fulfillment Signal to Interference plus Noise Ratio condition, the signal number that successive interference cancellation techniques can be used in network to eliminate is subject to the impact in path selected by route.Therefore, using the gain of successive interference cancellation techniques to increase overall end-to-end throughput in network to make full use of physical layer, needing to design a kind of Routing Protocol based on successive interference cancellation techniques.Regrettably, the route based on serial interference elimination only rests on theoretical research stage, does not have distributed method for routing to propose so far.

Owing to not considering to disturb the impact on wireless transmission, use the throughput amount of the wireless network of traditional method for routing lower, although although the cognitive route of existing interference can improve the throughput of network to a certain extent, its gain is by the how many impact in serious interference region in network and have the possibility increasing network interferences further.Serial interference elimination is a kind of new technology effectively alleviating interference and affect wireless transmission, but is only limitted to theoretical research based on the route of this technology, does not propose based on the distributed routing method of this technology so far.

Summary of the invention

The object of the invention is in conventional wireless network based on the deficiency of the cognitive method for routing of interference, propose a kind ofly to save the distributed network method for routing based on serial interference elimination that Internet resources significantly improve throughput.

The present invention is a kind of high throughput wireless distributed routing method based on serial interference elimination, and the technical scheme realizing the object of the invention comprises the steps:

Step 1, initialization step, namely each node in multi-hop wireless network sets up oneself neighbor node table, local information table and interfering link information table respectively, wherein local information table for deposit this node double bounce within the scope of the IP address of all nodes and the traffic information of geographical position and link, interfering link information table is all with this node link that is receiving node with its link name mutually disturbed with can eliminate information for depositing.

Step 2, when source node s has the service needed to destination node d to set up route, s broadcasts a routing request packet P to neighbor node _q.

Step 3, when intermediate node u receives routing request packet P _qtime, check P _qwhether through u, if then direct by P _qdelete; Otherwise to P _qbroadcasted after upgrading routing information:

(3a) when intermediate node u receives routing request packet P _qtime, check P _qwhether through u, if then direct by P _qdelete; Otherwise pass through P _qin record find upper hop node v, perform (3b);

(3b) represent with v with m the link be sending node u being receiving node, calculate the interference level I of link m _m, perform (3c) afterwards;

(3c) the space resources S consumed when link m transmits is calculated _m, perform (3d) afterwards;

(3d) by the IP address of node u and I _mand S _minsert routing request packet P _qin, by P _qbroadcast.

Step 4, destination node d is receiving first from the t after the routing request packet of source node s _wtime memory stores up all routing request packet received, t _wafter time, process is carried out to the routing request packet received and obtain optimum route P*, and send route replies bag P to source node s _r, terminate based on the Route establishment process of successive interference cancellation techniques:

(4a) when to receive first take s as the routing request packet of source node to destination node d, start timer, storing what receive before the timer expires take s as all routing request packet of source node, after timer expired, by receive all be that the routing request packet of source node abandons with s;

(4b) after timer expired, node d travels through all routing request packet stored, read nodal information and the link information of the path P recorded in each routing request packet successively, in computing network when node possesses serial interference elimination ability the interference level I of path P _pwith the space resources S of routing cost _p;

(4c) travel through all paths obtained in (4b), if there is no interference level is less than interference level thresholding T _ipath, then in all paths, find the optimal path P* of the minimum path of interference level as business; Otherwise, be less than T at interference level I _ipath in find the optimal path P* of a minimum path of space resources S consumed as business;

(4d) information of the optimal path P* selected is write route replies bag P _r, by P _rbe sent to source node s according to the reversing paths of path P *, the Route establishment process based on successive interference cancellation techniques terminates.

The present invention, in order to reduce the impact of interference on throughput of wireless networks, considers interference suffered by wireless link and link to the consumption of Internet resources, thus significantly improves the throughput of wireless network in routing decision process.The interference level I used in the present invention and space resources S, as route metric, by using above-mentioned route metric in routing decision process, makes full use of the advantage of serial interference elimination, finds interference level low and the path that drain space resource is little.Use method for routing of the present invention under the prerequisite ensureing current business throughput, reduce the consumption of business transmission to cyberspace resource as far as possible.

Realization of the present invention is also: the intermediate node u described in step (3b) calculates the interference level I of link m _m, comprise the steps:

(3b1) initialization I _m=0, the interfering link information table of query node u, obtains all interfering links of link m, then inquires about the traffic carrying capacity that local information table obtains all interfering links, finally by the title of the interfering link of link m and m and traffic carrying capacity stored in list L1, perform step (3b2);

(3b2) checking list L1, is the link circuit deleting of 0 by traffic carrying capacitys all in L1, to judge in L1 whether be empty, if so, then I _mcalculate complete, otherwise, perform step (3b3);

(3b3) Stochastic choice link n in L1, checks whether the number of the link in L1 except n is 0, if, then perform step (3b7), otherwise, in the link except n, select a link r, perform step (3b4) afterwards;

(3b4) judging whether link n and link r meets can conditions to release, if it is performs step (3b6), otherwise performs step (3b5);

(3b5) judge whether the link in L1 except n was all checked, if so, then performed step (3b7), otherwise not selected a link r by the link checked, perform step (3b4) afterwards;

(3b6) I is made _m=I _m+ min{B _n, B _r, wherein Bn is the traffic carrying capacity of the link n recorded in list L1, amendment link n traffic carrying capacity B _n, make B _n=B _n-min{B _n, B _r, amendment link r traffic carrying capacity B _r, B _r=B _r-min{B _n, B _r, then perform step (3b2);

(3b7) I is made _m=I _m+ B _n, the traffic carrying capacity of modification list L1 link n, makes B _n=0, then perform step (3b2).

Because serial interference elimination can make link receiving terminal eliminate part interference, make originally because mutually disturb the link that cannot transmit to be transmitted simultaneously simultaneously, thus significantly reduce interference level.The interference level I of link m _m, on the one hand with the traffic carrying capacity monotone nondecreasing of the interfering link of link m, on the other hand with the dull non-increasing of number of the serial interference elimination chance in the interfering link of link m.The interference level I of link m is calculated by above-mentioned steps _m, make interference level I _mcan embody the traffic carrying capacity of the interfering link of link m number, can embody again serial interference elimination to part interference alleviate effect.Interference level I _mbe that the path selecting interference level lower in follow-up routing decision process provides foundation as a route metric.

Realization of the present invention is also: the intermediate node u described in step (3c) calculates the space resources S that link m transmission consumes _m, comprise the steps:

(3c1) by inquiry interfering link information table and local information table, the mark obtaining link m " can eliminate " traffic carrying capacity of interfering link, if exist traffic carrying capacity be not 0 mark interfering link " can be eliminated ", then perform step (3c2), otherwise perform step (3c3);

(3c2) S is calculated _m, make S _mequal the space resources that link m individual transmission consumes;

(3c3) it is not the link of 0 that the mark traveling through link m " can eliminate " traffic carrying capacity in interfering link, calculates the distance of receiving node to node u of these links successively, compares that link n obtained apart from minimum, calculates S _m, make S _mequal the difference of space resources that link m and n use successive interference cancellation techniques to consume when transmitting simultaneously and the space resources that link n individual transmission consumes.

Because serial interference elimination can make two links of interference mutually originally be transmitted simultaneously, thus namely the spatial reuse degree effectively raising network has saved space resources, and this method calculates the space resources S of link m consumption by above-mentioned steps _mthe above-mentioned advantage of serial interference elimination can be fully demonstrated.Space resources S _mbe that the path selecting consumption network space resources less in follow-up routing decision process provides foundation as a route metric.

Realization of the present invention is also: the destination node d described in step (4b) calculates the interference level I of path P in routing request packet _pwith the space resources S consumed _p, comprise the steps:

(4b1) in path P every bar link interference level I in maximizing, as the interference level I of path P _p, namely $I_p=\underset{l\∈p}{\max }{I}_l;$

(4b2) the space resources S that bar link every in path P consumes is sued for peace, as the space resources S that path P consumes _p, namely $S_P=\underset{l\∈P}{\mathrm{\Σ}}{S}_l.$

Because the throughput in path is determined by the bottleneck link in path, obtain the interference level I of path P by maximizing in the interference level I of bar link every in path P in the method _p.Space resources due to routing cost is the space resources sum that in path, each link consumes, in the method by obtaining the space resources S that path P consumes to the space resources S summation of bar link consumption every in path P _p.Calculate each paths interference level I _pwith the space resources S consumed _pfor this method is selected one interference level is low and the path taking Internet resources few provides basis for estimation in routing decision process.

Compared with prior art, tool has the following advantages in the present invention:

1) physical layer new technology serial interference elimination is dissolved in the Routing Protocol based on interference avoidance mechanism by the present invention, thus reduces interference and to handle up quantitative limitation to radio network end-to-end.Apply successive interference cancellation techniques within the physical layer, the number of links that in network, unit are can be transmitted simultaneously can be made greatly to increase, the present invention, by utilizing the above-mentioned advantage of successive interference cancellation techniques, alleviates the impact that wireless link is interfered, thus improves the throughput of network.

2) the present invention is from the angle application successive interference cancellation techniques of network layer, changing traditional agreement based on successive interference cancellation techniques can only passively utilize existing interference in network to eliminate the present situation of chance, the chance that link uses serial interference elimination is created, the use of positive guide serial interference elimination by the region that Path selection is suitable in a network.

3) the present invention selects one to be disturbed the less path of impact by the interference level of more different paths bottleneck link, do like this consider all links in path with prior art interference level sum compared with, be more conducive to selecting the higher path of a throughput.

4) the cognitive route of existing interference only considers the annoyance level in path in routing decision process, and this often causes for selecting the path of a transmission quality optimum to take the more real estate impact of network thus can limiting the transmission of follow-up business.The present invention, from the angle improving overall network throughput, while considering the annoyance level suffered by path, have also contemplated that the cyberspace resource of routing cost, is conducive to the throughput ensureing follow-up business, thus improves overall network throughput.

5) the route metric annoyance level I that uses in Routing Protocol of the present invention and space resources S is that node analytical calculation on the basis of local information obtains, timing is used to give out a contract for a project compared with the method that detects with prior art, both decrease routing cost, turn improve the accuracy of route metric.

Accompanying drawing explanation

Fig. 1 is overall flow schematic diagram of the present invention;

Fig. 2 is route initialization and safeguard the sub-process figure of step in the present invention;

Fig. 3 is the sub-process figure of step performed by intermediate node and destination node in route process of establishing in the present invention, the wherein sub-process figure of Fig. 3 .1 to be the sub-process figure of step performed by intermediate node in Route establishment process, Fig. 3 .2 be step performed by destination node in Route establishment process;

Fig. 4 is a kind of form schematic diagram of local information table in the present invention;

Fig. 5 is a kind of form schematic diagram of interfering link information table in the present invention;

Fig. 6 is the interference level I that in the present invention, intermediate node u calculates link m _msub-process figure;

Fig. 7 is the space resources S that in the present invention, intermediate node u calculates link m consumption _mtime the schematic diagram of protection zone that needs when m and link n serializable disturb and eliminate;

Fig. 8 is the change curve that the throughput of three kinds of method for routing of the embodiment of the present invention 4 increases with business demand;

Fig. 9 is the change curve that the throughput of three kinds of method for routing in the embodiment of the present invention 4 increases with business number;

Figure 10 is the scene topological diagram of the embodiment of the present invention 5.

Embodiment

Below in conjunction with accompanying drawing to the detailed description of the invention

Embodiment 1

This example, from a single-channel multi-hop wireless network, illustrates implementation process of the present invention.Suppose that network area is A, in network, have n node { x ₁..., x _nbe evenly distributed in this scene, and each node has an omnidirectional antenna, transmitted power P fixes, and transmission range is R _t, under being operated in half-duplex mechanism.The path-loss factor of wireless channel is α >=2, and all nodes are with fixing speed R transmission, and the Signal to Interference plus Noise Ratio thresholding needed for receiving terminal decoding success is β > 1.Each node in network has the ability using serial interference elimination, and such as serial interference elimination ability directly can be realized by the CSM6850 chip of QUALCOMM company, and MAC layer uses the center type dispatching algorithm based on serial interference elimination.

The present invention is a kind of high throughput wireless distributed routing method based on serial interference elimination, see Fig. 1, includes following steps:

Step 1, initialization step, each node in multi-hop wireless network is set up respectively and is safeguarded oneself neighbor node table, local information table and interfering link information table, wherein neighbor node table is for depositing IP address and the geographical position of all neighbor nodes of this node, local information table for deposit this node double bounce within the scope of the IP address of all nodes and the traffic carrying capacity of geographical position and link, interfering link information table is all with this node link that is receiving node with the title of its link information mutually disturbed with can eliminate information for depositing, the link information mutually disturbed with it refers to and the link information that the link being receiving node with this node disturbs mutually, initialization procedure is see Fig. 2, specifically comprise:

(1a) node identifies the neighbor node of oneself by exchanging hello bag, sets up the neighbor node table of oneself and safeguards, being implemented as follows of this step:

(1a1) each node moment of random choose within shorter time period sends hello bag towards periphery, indicates oneself node IP address and geographical position in hello bag;

(1a2) after a node receives hello bag, that in the neighbor node table of oneself, searches hello bag sends node whether in the neighbor node table of oneself, if, then upgrade the timestamp of its place list item, otherwise, a newly-built list item, adds the node IP address and geographical position that send hello bag in the table entry, and is inserted by this list item in the neighbor node table of oneself;

(1a3) each node periodically sends hello bag, and the hello bag simultaneously sent by the neighbor node regularly received is safeguarded the neighbor node table of oneself.

(1b) each node obtains all node IP address and geographical position and link traffic within the scope of double bounce by exchanging information of neighbor nodes bag, and the local information table setting up oneself is gone forward side by side the maintenance of line period;

(1c) each node obtains with from as the interfering link of all links of receiving end and whether serializable interference elimination information by analyzing local information, set up interfering link information table and safeguard, interfering link information tableau format is with reference to Fig. 5, the list item that interfering link information table is index by the link being receiving node with this node forms, each list item comprises the title of the interfering link of index link and can eliminate flag information, being implemented as follows of this step:

(1c1) set up the interfering link information table of oneself for node w, first all vertex ticks in the neighbor node table of oneself are " untreated " by node w, then perform step (1c2);

(1c2) node w inquires about the neighbor node table of oneself, checks whether the node of mark " untreated ", if do not had, then interfering link information table has been set up, and performs step (1c5) and carries out periodic maintenance.Otherwise, find the node v of a mark " untreated ", obtain taking v as transmitting terminal w the link m being receiving terminal, then by v mark " processed ", perform step (1c3) afterwards;

(1c3) list item that to set up with link-local m in interfering link information table be index, performs step (1c4);

(1c4) node w travels through the every bar link in local information table, check and whether mutually disturb with link m, mutual interference refer to when node without link m when serial interference elimination ability and link n because mutual interference can not be transmitted simultaneously, concrete determination methods is as follows: the sending node and the receiving node that represent link n with node i and j respectively, if node i, relation between j, v, w meet:

$\left\{\begin{array}{c}\left|\mathrm{vj}\right|<{\mathrm{\&beta;}}^{\frac{1}{\mathrm{\&alpha;}}}\left|\mathrm{ij}\right|\\ \left|\mathrm{iw}\right|<{\mathrm{\&beta;}}^{\frac{1}{\mathrm{\&alpha;}}}\left|\mathrm{vw}\right|\end{array}\right.,$

Then link m and link n disturbs mutually, and wherein β is that receiver successfully receives required Signal to Interference plus Noise Ratio thresholding, and a is the path fading index of channel, | vw| represents the distance between node w and node v; If link m and link n non-interference, directly skip link n and do not perform any operation.

If link m and link n disturbs mutually, judge whether link m and link n can realize transmitting by serial interference technology simultaneously, concrete determination methods is as follows: the sending node and the receiving node that represent link n with node i and j respectively, checks whether node i, relation between j, v, w meet one of following 3 kinds of situations:

$\left(1\right)\left\{\begin{array}{c}\left|\mathrm{vj}\right|\&le;{(\mathrm{\&beta;}+1)}^{-\frac{1}{\mathrm{\&alpha;}}}\left|\mathrm{ij}\right|\\ \left|\mathrm{iw}\right|\&GreaterEqual;{\mathrm{\&beta;}}^{\frac{1}{\mathrm{\&alpha;}}}\left|\mathrm{vw}\right|\end{array}\right.$ $\left(2\right)\left\{\begin{array}{c}\left|\mathrm{vj}\right|\&GreaterEqual;{\mathrm{\&beta;}}^{\frac{1}{\mathrm{\&alpha;}}}\left|\mathrm{ij}\right|\\ \left|\mathrm{iw}\right|\&le;{(\mathrm{\&beta;}+1)}^{-\frac{1}{\mathrm{\&alpha;}}}\left|\mathrm{vw}\right|\end{array}\right.$ $\left(3\right)\left\{\begin{array}{c}\left|\mathrm{vj}\right|\&le;{(\mathrm{\&beta;}+1)}^{-\frac{1}{\mathrm{\&alpha;}}}\left|\mathrm{ij}\right|\\ \left|\mathrm{iw}\right|\&le;{(\mathrm{\&beta;}+1)}^{-\frac{1}{\mathrm{\&alpha;}}}\left|\mathrm{vw}\right|\end{array}\right.,$

If satisfied condition, then link n being marked " can eliminate " inserts with in the link-local m list item that is index afterwards, otherwise, link n being marked " can not eliminate " inserts with in the link-local m list item that is index afterwards, return step (1c2), check whether also have untreated neighbor node;

(1c5), after interfering link information table has been set up, the periodic setting up procedure of node (1c1) upgrades interfering link information table.

By setting up the relation that interfering link information table makes serial interference elimination whether can be used to transmit between the interfering link of node acquisition link of node for the purpose of this node and link simultaneously in step 1, provide essential information for calculating route metric in routing procedure.

Step 2, source node s sends routing request packet.

When there being new business to arrive source node s, s is to all neighbor node broadcast route request bag P _q, in routing request packet, comprise P _qthe node of process and the information of link.

Step 3, intermediate node u process routing request packet, see Fig. 3 .1, concrete steps comprise:

(3a) intermediate node u receives routing request packet P _qafter first check bag in path, if comprise node u in path, then direct by P _qdelete, otherwise, from path, extract upper hop node v, then perform step (3b);

(3b) represent with v with m the link be sending node u being receiving node, node u calculates the interference level I of link m according to the data in local information table and interfering link information table table _m, with reference to Fig. 6, the specific implementation of this step comprises:

(3b1) initialization interference level, makes I _m=0, the interfering link information table of query node u, obtains all interfering links of link m, then inquires about the traffic carrying capacity that local information table obtains all interfering links, finally by the title of the interfering link of link m and m and traffic carrying capacity stored in list L1, perform step (3b2);

(3b2) checking list L1, is the link circuit deleting of 0 by traffic carrying capacitys all in L1, judges that whether L1 is empty, if so, then I _mcalculate complete, perform step (3c), otherwise namely L1 is not empty, performs step (3b3);

(3b3) Stochastic choice link n in L1, checks whether the number of the link in L1 except n is 0, if, then perform step (3b7), otherwise, in the link except n, select a link r, perform step (3b4) afterwards;

(3b4) judging whether link n and link r meets can conditions to release, and if so, namely meet can conditions to release for link n and link r, then perform step (3b6), otherwise perform step (3b5);

(3b5) judge whether the link in L1 except n was all checked, if so, then performed step (3b7), otherwise not selected a link r by the link checked, perform step (3b4) afterwards;

(3b6) the interference level I of link m is made _m=I _m+ min{B _n, B _r, wherein B _nthe traffic carrying capacity of the link n recorded in list L1, amendment link n traffic carrying capacity B _n, make B _n=B _n-min{B _n, B _r, the traffic carrying capacity B of amendment link r _r, make B _r=B _r-min{B _n, B _r, then perform step (3b2);

(3b7) I is made _m=I _m+ B _n, the traffic carrying capacity of modification list L1 link n, makes B _n=0, then perform step (3b2).

(3c) node u calculates the space resources S that link m transmission consumes _m, detailed process is:

(3c1) obtain mutually disturbing with link m by inquiry interfering link information table and mark the link of " can eliminate ", then the traffic carrying capacity of above-mentioned link is obtained by inquiry local information table, namely mutually disturb with link m and mark the traffic carrying capacity of the link of " can eliminate ", if mutually disturb with link m and mark in the link of " can eliminate " and there is the link that traffic carrying capacity is not 0, then perform step (3c3), otherwise perform step (3c2);

(3c2) the space resources S that link m consumes is calculated _m, make S _mequal the protection zone area needed for link m individual transmission, perform step (3d) afterwards;

(3c3) traversal and link m mutually disturb and mark traffic carrying capacity in the link of " can eliminate " is not the link of 0, calculate the distance of receiving node to node u of these links successively, relatively obtain apart from minimum that link n, calculate the space resources S that link m transmission consumes _m, make S _mequal the difference of required protection zone area and the protection zone area needed for link n individual transmission when link m and n uses successive interference cancellation techniques to transmit simultaneously, namely obtain link m and transmit the space resources S consumed _m, perform step (3d) afterwards.

(3d) node u is by the IP address of oneself and I _mand S _minsert routing request packet P _qin; Then by routing request packet P _qbroadcast.

About the route metric of link m and interference level I in step 3 _mwith space resources S _mcalculating be one of core of the present invention, by calculating the interference level I of link m _mwith space resources S _m, in order to select one in the follow-up routing decision stage, interference level is low and consumption of network resources is few path provides decision-making foundation.

Step 4, destination node d is receiving first from the t after the routing request packet of source node s _wtime memory stores up all routing request packet received, t _wafter time, process is carried out to the routing request packet received and obtain optimum route P*, and send route replies bag P to source node s _r, t _wtime can pass through timer sets, and see Fig. 3 .2, its concrete steps comprise:

(4a), after destination node d receives the routing request packet from s first, start timer, timer sets time-out time is t _w, record all routing request packet received before the timer expires;

(4b), after timer expired, node d reads the routing information recorded in each routing request packet successively, in path P every bar link interference level I in maximizing, as the interference level I of path P _p, namely again the space resources S that bar link every in path P consumes is sued for peace, as the space resources S that path P consumes _p, namely then by path P and tolerance I thereof _pand S _pbe stored in together in list B1.

(4c) all in traversal of lists B1 paths, if the interference level I of path P _pbe less than interference level thresholding T _i, interference level thresholding is an empirical data, can select, then path P be stored in list B2 between 0-1.

(4d) in the routing decision stage, destination node d attempts selection one in the path ensureing that under the prerequisite that suffered interference level is lower, consumption network space resources is minimum, if the interference level in all paths in network is all very high, then select the path that an interference level is minimum, namely first destination node d checks whether list B2 is empty table, if B2 is not empty table, then mean in network to there is the lower path of interference level, now destination node d finds the optimal path P* of a minimum path of space resources S consumed as business in B2; If B2 is empty table, then mean in network there is not the lower path of interference level, now destination node d finds the optimal path P* of the minimum path of interference level I as business in B1;

(4e) by the information of path P * write route replies bag P _r, by P _rbe sent to source node s according to the reversing paths of path P *, empty list B1 and B2, the Route establishment process based on successive interference cancellation techniques terminates.

Obtaining an optimal path to path information processing in routing request packet in step 4 is one of core of the present invention, obtained interference level I and the space resources S in different path by the routing information destination node in extraction process routing request packet, destination node obtains the low and path that consumption of network resources is few of interference level thus.

A kind of route metric based on successive interference cancellation techniques is devised in the present invention, this route metric comprises interference level I and space resources S, by using this route metric, this method for routing makes full use of successive interference cancellation techniques in the advantage alleviating interference and improve in spatial reuse degree, thus it is low and take the less path of drain space resource to obtain interference level, significantly improves the entire throughput of network.Wherein intermediate node u calculating route metric and destination node d obtain optimal path according to route metric is core of the present invention.

Physical layer new technology serial interference elimination is dissolved in the Routing Protocol based on interference avoidance mechanism by the present invention, thus reduces interference and to handle up quantitative limitation to radio network end-to-end.Apply successive interference cancellation techniques within the physical layer, the number of links that in network, unit are can be transmitted simultaneously can be made greatly to increase, the present invention, by utilizing the above-mentioned advantage of successive interference cancellation techniques, alleviates the impact that wireless link is interfered, thus improves the throughput of network.

Embodiment 2

Based on the high throughput wireless distributed routing method of serial interference elimination with embodiment 1.Local information tableau format wherein in step (1b) as shown in Figure 4, local information table is made up of the list item being index with the neighbor node of this node, each list item deposits the IP address of the neighbor node of index node, geographical position and from index node to the traffic carrying capacity of this neighbor node, and it is as follows that it sets up mode.

(1b1) after the neighbor node table of node u is set up, within shorter time period, random choose moment is to the neighbor node broadcast information of neighbor nodes bag of oneself, the IP address of all neighbor nodes of node u and geographical position and this node traffic carrying capacity to each neighbor node in present period is comprised in information of neighbor nodes bag, the circular of traffic carrying capacity is as follows: the traffic carrying capacity B being transferred to node u for T time interior nodes v wherein N is the number that T time interior nodes v is transferred to the packet of node u, and S is the size of each packet, and R is the transmission rate of node v to node u;

(1b2) after the information of neighbor nodes bag received from node v as a node u, the list item that whether to exist with node v be index is searched in the local information table of oneself, if exist, then upgrade the traffic carrying capacity of this list item interior joint v to a neighbor node, otherwise, the newly-built list item that is index with node v, comprises the neighbor node IP of node v and geographical position and the v traffic carrying capacity to each neighbor node business in this list item;

(1b3) each node periodically sends information of neighbor nodes bag, and the local information table of information of neighbor nodes bag to oneself simultaneously sent by the neighbor node regularly received is safeguarded.

Embodiment 3

Based on the high throughput wireless distributed routing method of serial interference elimination with embodiment 1-2.Wherein step (3c) also can realize as follows:

(3c1) interfering link information table and local information table is searched, find out in the interfering link of link m and mark " can eliminate " and the non-vanishing link of traffic carrying capacity is put into list L2 and checked whether list L2 is empty table, if, then perform step (3c2), otherwise perform step (3c3);

(3c2) S is calculated _m=A1, wherein A1 is the protection zone Z needed for link m individual transmission _marea, Z _mfor center of circle radius is with node u circle, perform step (3d) by broadcast route request bag after information updating.

(3c3) when L2 is not empty table, each link in traversal of lists L2, calculates the distance of receiving node to node u of these links successively, compares that link n obtained apart from minimum, calculates S _m=A2-A3, wherein A2 is the protection zone Z required when simultaneously transmitting of link m and n _mnarea, Z _mnbe that the center of circle is respectively node u and 1, radius is respectively with two circle cover regions, node k and node 1 are sending node and the receiving node of link n respectively, and A3 is the protection zone Z needed for link n individual transmission _narea, Z _nfor center of circle radius is with node 1 circle, Z _mnand Z _nrelation as shown in Figure 7, perform step (3d) by broadcast route request bag after information updating.

High throughput wireless distributed network method for routing based on serial interference elimination of the present invention, improves the problem that the cognitive route network throughput of traditional interference is low and consumption of network resources is more.Its implementation procedure is: each node is set up and maintenance of neighbor node table, local information table and interfering link information table; When business arrives, source node broadcasts is by asking bag; Intermediate node receives routing request packet, is broadcasted after upgrading the routing information of this bag; Destination node stores the routing request packet of these business all received in a period of time after receiving first routing request packet, an optimal path is obtained subsequently by the routing information processed in these routing request packet, finally, destination node sends route replies bag to source node.Invention increases the throughput of multi-hop wireless network, can be used for the routing procedure of multi-hop wireless distributed network.

Embodiment 4

Based on the high throughput wireless distributed routing method of serial interference elimination with embodiment 1-3.This example illustrates the gain of the present invention to network throughput by the emulation of a concrete scene.

1. simulating scenes

Suppose that network scenarios is 750m × 750m, in network, have 36 node { x ₁..., x ₃₆be evenly distributed in this scene, and each node has an omnidirectional antenna, transmitted power P fixes, and transmission range is 250m, under being operated in half-duplex mechanism.The path-loss factor of wireless channel is α=3, and all nodes are with fixing speed R transmission, and the Signal to Interference plus Noise Ratio thresholding needed for receiving terminal decoding success is β=2.Each node in network has the ability using serial interference elimination, the center type dispatching algorithm based on serial interference elimination that MAC layer uses the document " Schedulinginwirelessadhocnetworkswithsuccessiveinterfere ncecancellation " be published on 2011ProceedingsIEEEINFOCOM by people such as Lv to propose.Use the throughput performance of simulation software OPNET-Modeler diplomatic copy method for routing, and the throughput performance of shortest route traditional under using same scene and the cognitive route of interference contrasts.

2. simulation result and analysis

Fig. 8 is the change curve that the throughput of three kinds of method for routing increases with business demand.Wherein abscissa is the speed of each business, and ordinate is network throughput.Have the business of 8 random distribution to transmit in network, the speed of each business is incremented to 1.5Mbps from 0.2Mbps simultaneously.As can be seen from Figure 8: owing to not considering the impact disturbed, the throughput of shortest route method is minimum, reaches capacity when service rate in network reaches 0.7Mbps; Disturb the throughput of cognitive route to be significantly higher than shortest route, reach capacity when service rate in network is 1Mbps; Owing to taking full advantage of the advantage of successive interference cancellation techniques, the throughput of this method is the highest, with traditional shortest route with disturb cognitive route and compare the gain that can obtain 78% and 29% respectively.

Fig. 9 is the change curve that the throughput of three kinds of method for routing increases with business number.Wherein abscissa is the number of business in network, and ordinate is network throughput.In network, each business is with the speed rates of 1Mbps, and the number of business is incremented to 12 from 4.As can be seen from Figure 9 this method throughput and traditional shortest route with disturb cognitive route and compare the gain that can obtain 84% and 28% respectively.

The gain of this method for routing mainly comes from two aspects: 1. this method for routing considers the impact of interference on wireless transmission in routing decision process, thus makes the path of selection avoid interference too high region.2. in routing decision process, this method for routing considers that successive interference cancellation techniques alleviates the performance of interference and conserve space resource, thus one can be selected to take the less path of Internet resources, enables network carry more follow-up business.

Embodiment 5

Based on the high throughput wireless distributed routing method of serial interference elimination with embodiment 1-3.This example illustrates the implementation process of method for routing of the present invention by the emulation of a concrete scene.

As shown in Figure 10, comprise 7 nodes s, a, b, c, d, e, f, its position is represented by coordinate in Figure 10 the topology of network.In network, all nodes all have an omnidirectional antenna, and transmitted power P fixes, under being operated in half-duplex mechanism.The path-loss factor of wireless channel is α=2, and all nodes are with fixing speed R=1Mbps transmission, and the Signal to Interference plus Noise Ratio thresholding needed for receiving terminal decoding success is β=4.The link that it is receiving terminal for transmitting terminal with node b that use link ab represents with node a, all the other links by that analogy.Suppose that the upper existing constant service stream of link ab, bc, cf, ef exists, its traffic carrying capacity is respectively: 0.1,0.1,0.2,0.3.Known link ef and link cf can use successive interference cancellation techniques to transmit simultaneously, interference level thresholding T _i=0.6.Suppose that node s has speed to be that the service needed of 0.1Mbps is transferred to node d, use method for routing of the present invention to find an optimal path and comprise the steps:

Step 1: each node in network sets up oneself neighbor node table, local information table and interfering link information table respectively.For node a, comprise IP address and the geographical location information of its neighbor node s, b, e in the neighbor node table of node a, neighbor node table is table conventional in routing procedure, namely

The local information table of node a is:

The interfering link information table of node a is:

Step 2: source node s sends routing request packet P _q.

Step 3: intermediate node receives routing request packet P _qafter, for node a, it performs following steps:

(3a) first node a judges P _qnoly pass through oneself, if then direct by P _qdelete; Otherwise from routing request packet P _qin find P _qupper hop node be s.

(3b) node a calculates the interference level I of link sa _saand the space resources S consumed _sa.By the data in inquiry local information table and interfering link information table, the interfering link obtaining link sa of node a is ab, bc, ae, ef, and its traffic carrying capacity is respectively 0.1,0.1,0,0.3, uses embodiment 1 step (3b) to obtain I thus _sa=0.5, by the data in inquiry interfering link information table, find that link sa does not mark the interfering link of " can eliminate ", the step (3c2) performed in embodiment 3 calculates S _sa=4 π.

(3c) by the IP address of node a and I _saand S _sainsert routing request packet P _qafter, and by P _qbroadcast.

Step 4: destination node d receives two routing request packet, respectively through path P 1:s-a-b-c-f-d and path P 2:s-a-e-f-d.Read the path metric of two paths successively, wherein in path P 1, the interference level of 5 links is respectively: 0.5,0.5,0.5,0.5,0.4, consume space resources be respectively: 4 π, 4 π, 4 π, 0,4 π, in path P 2, the interference level of 4 links is respectively: 0.5,0.5,0.5,0.4, the space resources consumed is respectively: 4 π, 8 π, 4 π, 4 π, the path metric calculating P1 is I _p1=0.5, S _p1=16 π, the path metric calculating P2 is I _p2=0.5, S _p2=20 π.I can be obtained by the interference level comparing two links _p1=I _p2< T _i, namely the interference level of two paths is not high, and the space resources then comparing two link consumption can obtain S _p1< S _p2, therefore, destination node d obtains path P 1 for optimal path, and P1 is herein optimal path P*.Path P 1 is put into path response packet P by node d _rin, by P _rsend to source node s by the reversing paths of P1 and d-f-c-b-a-s, the routing procedure from source node s to destination node d terminates.

Letter and state it, the invention discloses a kind of high throughput wireless distributed network method for routing based on serial interference elimination, its implementation procedure is: each node is set up and maintenance of neighbor node table, local information table and interfering link information table; When business arrives, source node broadcasts is by asking bag; Intermediate node receives routing request packet, after calculating the interference level of link and the space resources of consumption, upgrades route requests package informatin and broadcasts; The routing request packet that destination node process receives obtains the route metric in wherein path, i.e. interference level and space resources, then the tolerance by comparing path obtains an optimal path, finally, destination node sends route replies bag to source node, and the routing procedure based on serial interference elimination terminates.The invention solves the problem that the cognitive route entire throughput of traditional interference is low and consumption of network resources is more, significantly improve the entire throughput of multi-hop wireless network, can be used for the routing procedure of multi-hop wireless distributed network.

Claims (2)

1., based on a high throughput wireless distributed network method for routing for serial interference elimination, it is characterized in that: include following steps:

Step 1, initialization step, namely each node in multi-hop wireless network sets up oneself neighbor node table, local information table and interfering link information table respectively, wherein local information table for deposit this node double bounce within the scope of the IP address of all nodes and the traffic information of geographical position and link, interfering link information table is all with this node link information that is receiving node, the link information mutually disturbed with above-mentioned link with can eliminate information for depositing, wherein, the foundation of interfering link information table is realized to step (1c5) by step (1c1):

(1c1) set up the interfering link information table of oneself for present node w, first all vertex ticks in the neighbor node table of oneself are " untreated " by node w, then perform step (1c2);

(1c2) node w inquires about the neighbor node table of oneself, checks whether the node of mark " untreated ", if do not had, then interfering link information table has been set up; Otherwise, find the node v of a mark " untreated ", obtain taking v as transmitting terminal w the link m being receiving terminal, then node v is marked " processed ", perform step (1c3) afterwards;

(1c3) list item that to set up with link-local m in interfering link information table be index, performs step (1c4);

(1c4) node w travels through the every bar link in local information table, check and whether mutually disturb with link m, mutual interference refer to when node without link m when serial interference elimination ability and link n because mutual interference can not be transmitted simultaneously, concrete determination methods is as follows: the sending node and the receiving node that represent link n with node i and j respectively, if node i, relation between j, v, w meet:

$\{\begin{array}{c}\left|vj\right|<{\mathrm{\&beta;}}^{\frac{1}{\mathrm{\&alpha;}}}\left|ij\right|\\ \left|iw\right|<{\mathrm{\&beta;}}^{\frac{1}{\mathrm{\&alpha;}}}\left|vw\right|\end{array},$

Then link m and link n disturbs mutually, and wherein β is that receiver successfully receives required Signal to Interference plus Noise Ratio thresholding, and α is the path fading index of channel, | vw| represents the distance between node w and node v; If link m and link n non-interference, directly skip link n and do not perform any operation,

If link m and link n disturbs mutually, judge whether link m and link n can realize transmitting by serial interference technology simultaneously, concrete determination methods is as follows: the sending node and the receiving node that represent link n with node i and j respectively, checks whether node i, relation between j, v, w meet one of following 3 kinds of situations:

$\begin{array}{ccc}\left(1\right)\left\{\begin{array}{c}\left|vj\right|\&le;{(\mathrm{\&beta;}+1)}^{-\frac{1}{\mathrm{\&alpha;}}}\left|ij\right|\\ \left|iw\right|\&GreaterEqual;{\mathrm{\&beta;}}^{\frac{1}{\mathrm{\&alpha;}}}\left|vw\right|\end{array}\right.& \left(2\right)\left\{\begin{array}{c}\left|vj\right|\&le;{\mathrm{\&beta;}}^{\frac{1}{\mathrm{\&alpha;}}}\left|ij\right|\\ \left|iw\right|\&le;{(\mathrm{\&beta;}+1)}^{-\frac{1}{\mathrm{\&alpha;}}}\left|vw\right|\end{array}\right.& \left(3\right)\{\begin{array}{c}\left|vj\right|\&le;{(\mathrm{\&beta;}+1)}^{-\frac{1}{\mathrm{\&alpha;}}}\left|ij\right|\\ \left|iw\right|\&le;{(\mathrm{\&beta;}+1)}^{-\frac{1}{\mathrm{\&alpha;}}}\left|vw\right|\end{array},\end{array}$

If satisfied condition, then link n being marked " can eliminate " inserts with in the link-local m list item that is index afterwards, otherwise, link n being marked " can not eliminate " inserts with in the link-local m list item that is index afterwards, return step (1c2), check whether also have untreated neighbor node;

(1c5), after interfering link information table has been set up, the periodic setting up procedure of node (1c1) upgrades interfering link information table;

Step 2, when source node s has the service needed to destination node d to set up route, s broadcasts a routing request packet P to neighbor node _q;

Step 3, when intermediate node u receives routing request packet P _qtime, check P _qwhether through u, if then direct by P _qdelete; Otherwise to P _qbroadcasted after upgrading routing information:

(3a) when intermediate node u receives routing request packet P _qtime, check P _qwhether through u, if then direct by P _qdelete; Otherwise pass through P _qin record find upper hop node v, perform (3b);

(3b) represent with v with m the link be sending node u being receiving node, calculate the interference level I of link m _m, perform (3c) afterwards, wherein calculate the interference level I of link m _mrealized to step (3b7) by step (3b1):

(3b1) initialization interference level, makes I _m=0, the interfering link information table of query node u, obtains all interfering links of link m, then inquires about the traffic carrying capacity that local information table obtains all interfering links, finally by the title of the interfering link of link m and m and traffic carrying capacity stored in list L1, perform step (3b2);

(3b2) checking list L1, is the link circuit deleting of 0 by traffic carrying capacitys all in L1, judges that whether L1 is empty, if so, then I _mcalculate complete, perform step (3c), otherwise namely L1 is not empty, performs step (3b3);

(3b3) Stochastic choice link n in L1, checks whether the number of the link in L1 except n is 0, if, then perform step (3b7), otherwise, in the link except n, select a link r, perform step (3b4) afterwards;

(3b4) judging whether link n and link r meets can conditions to release, and if so, namely meet can conditions to release for link n and link r, then perform step (3b6), otherwise perform step (3b5);

(3b5) judge whether the link in L1 except n was all checked, if so, then performed step (3b7), otherwise not selected a link r by the link checked, perform step (3b4) afterwards;

(3b6) the interference level I of link m is made _m=I _m+ min{B _n, B _r, wherein B _nthe traffic carrying capacity of the link n recorded in list L1, amendment link n traffic carrying capacity B _n, make B _n=B _n-min{B _n, B _r, the traffic carrying capacity B of amendment link r _r, make B _r=B _r-min{B _n, B _r, then perform step (3b2);

(3b7) I is made _m=I _m+ B _n, the traffic carrying capacity of modification list L1 link n, makes B _n=0, then perform step (3b2);

(3c) the space resources S consumed when link m transmits is calculated _m, perform step (3d), detailed process is:

(3c1) obtain mutually disturbing with link m by inquiry interfering link information table and mark the link of " can eliminate ", then the traffic carrying capacity of above-mentioned link is obtained by inquiry local information table, namely mutually disturb with link m and mark the traffic carrying capacity of the link of " can eliminate ", if mutually disturb with link m and mark in the link of " can eliminate " and there is the link that traffic carrying capacity is not 0, then perform step (3c3), otherwise perform step (3c2);

(3c2) the space resources S that link m consumes is calculated _m, make S _mequal the protection zone area needed for link m individual transmission, perform step (3d) afterwards;

(3c3) traversal and link m mutually disturb and mark traffic carrying capacity in the link of " can eliminate " is not the link of 0, calculate the distance of receiving node to node u of these links successively, relatively obtain apart from minimum that link n, calculate the space resources S that link m transmission consumes _m, make S _mequal the difference of required protection zone area and the protection zone area needed for link n individual transmission when link m and n uses successive interference cancellation techniques to transmit simultaneously, namely obtain link m and transmit the space resources S consumed _m, perform step (3d) afterwards;

(3d) by the IP address of node u and I _mand S _minsert routing request packet P _qin, by P _qbroadcast;

Step 4, destination node d is receiving first from the t after the routing request packet of source node s _wtime memory stores up all routing request packet received, t _wafter time, process is carried out to the routing request packet received and obtain optimum route P*, and send route replies bag P to source node s _r, comprise the steps:

(4a) when to receive first take s as the routing request packet of source node to destination node d, start timer, storing what receive before the timer expires take s as all routing request packet of source node, after timer expired, by receive all be that the routing request packet of source node abandons with s;

(4b), after timer expired, node d travels through all routing request packet stored, and reads nodal information and the link information of the path P recorded in each routing request packet successively, the interference level I of path P in computing network _pwith the space resources S of routing cost _p, concrete steps are as follows:

(4b1) the interference level I of every bar link 1 in path P ₁middle maximizing, as the interference level I of path P _p, namely $I_p=\underset{1\&Element;P}{\max }{I}_1;$

(4b2) to the space resources S that bar link 1 every in path P consumes ₁summation, as the space resources S that path P consumes _p, namely $S_p=\underset{1\&Element;P}{\&Sigma;}{S}_1;$

(4c) travel through all paths obtained in (4b), if there is no interference level is less than interference level thresholding T _ipath, then in all paths, find the optimal path P* of the minimum path of interference level as business; Otherwise, be less than T at interference level I _ipath in find the optimal path P* of a minimum path of space resources S consumed as business;

(4d) information of the optimal path P* selected is write route replies bag P _r, by P _rbe sent to source node s according to the reversing paths of path P *, complete the distributed routing procedure of high throughput wireless based on serial interference elimination.

2. the high throughput wireless distributed network method for routing based on serial interference elimination according to claim 1, it is characterized in that: each node in the network described in step 1 sets up oneself neighbor node table, local information table and interfering link information table respectively, comprises the steps:

(1a) in multi-hop wireless network, obtain IP address and the geographical position of the neighbor node of oneself between node by exchanging hello bag, each node sets up the neighbor node table of oneself according to the information in the hello bag received;

(1b), after node completes neighbor node table, the neighbor information being exchanged oneself by regular and neighbor node obtains the IP address of all nodes within the scope of double bounce and the traffic carrying capacity of geographical position and link, thus sets up local information table;

(1c), after the local information table of node completes, obtain all with this node link that is receiving node and the title of link mutually disturbed with above-mentioned link with can information be eliminated by analyzing local information, thus set up interfering link information table.