CN108924851A - Cognition wireless sensor network QoS based on directional aerial ensures chance method for routing - Google Patents
Cognition wireless sensor network QoS based on directional aerial ensures chance method for routing Download PDFInfo
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- CN108924851A CN108924851A CN201811148566.3A CN201811148566A CN108924851A CN 108924851 A CN108924851 A CN 108924851A CN 201811148566 A CN201811148566 A CN 201811148566A CN 108924851 A CN108924851 A CN 108924851A
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04W—WIRELESS COMMUNICATION NETWORKS
- H04W16/00—Network planning, e.g. coverage or traffic planning tools; Network deployment, e.g. resource partitioning or cells structures
- H04W16/22—Traffic simulation tools or models
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04W—WIRELESS COMMUNICATION NETWORKS
- H04W28/00—Network traffic management; Network resource management
- H04W28/16—Central resource management; Negotiation of resources or communication parameters, e.g. negotiating bandwidth or QoS [Quality of Service]
- H04W28/24—Negotiating SLA [Service Level Agreement]; Negotiating QoS [Quality of Service]
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04W—WIRELESS COMMUNICATION NETWORKS
- H04W40/00—Communication routing or communication path finding
- H04W40/02—Communication route or path selection, e.g. power-based or shortest path routing
- H04W40/04—Communication route or path selection, e.g. power-based or shortest path routing based on wireless node resources
- H04W40/06—Communication route or path selection, e.g. power-based or shortest path routing based on wireless node resources based on characteristics of available antennas
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04W—WIRELESS COMMUNICATION NETWORKS
- H04W40/00—Communication routing or communication path finding
- H04W40/02—Communication route or path selection, e.g. power-based or shortest path routing
- H04W40/12—Communication route or path selection, e.g. power-based or shortest path routing based on transmission quality or channel quality
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04W—WIRELESS COMMUNICATION NETWORKS
- H04W40/00—Communication routing or communication path finding
- H04W40/02—Communication route or path selection, e.g. power-based or shortest path routing
- H04W40/12—Communication route or path selection, e.g. power-based or shortest path routing based on transmission quality or channel quality
- H04W40/14—Communication route or path selection, e.g. power-based or shortest path routing based on transmission quality or channel quality based on stability
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04W—WIRELESS COMMUNICATION NETWORKS
- H04W84/00—Network topologies
- H04W84/18—Self-organising networks, e.g. ad-hoc networks or sensor networks
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02D—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN INFORMATION AND COMMUNICATION TECHNOLOGIES [ICT], I.E. INFORMATION AND COMMUNICATION TECHNOLOGIES AIMING AT THE REDUCTION OF THEIR OWN ENERGY USE
- Y02D30/00—Reducing energy consumption in communication networks
- Y02D30/70—Reducing energy consumption in communication networks in wireless communication networks
Abstract
The invention discloses a kind of, and the cognition wireless sensor network QoS based on directional aerial ensures chance method for routing, belongs to directional aerial with cognition wireless sensor network and routes the field combined.The method of the invention includes the following steps：Firstly, analysis directional aerial adjusts the influence to frequency spectrum access and Route Selection；Secondly, modeling to antenna system, network model, and the combined optimization problem of antenna sector, transmission channel and Route Selection is proposed on this basis.Then, a kind of approximate schemes and heuritic approach are proposed, to select for the antenna sector of data transmission and channel, create candidate forward node list.Finally, carrying out emulation experiment and interpretation of result.The present invention can be well adapted for the environment of cognitive radio network of usable spectrum dynamic change, and provide high reliability, low energy consumption, the QoS guarantee of low delay.
Description
Technical field
The present invention relates to a kind of cognition wireless sensor network QoSs to ensure chance routing mechanism, belongs to directional aerial and recognizes
Know the field that wireless sensor network routing combines.
Background technique
Existing wireless sensor network mostly works in the ISM band without authorization, but as new generation of wireless is set
Standby is universal, these common unauthorized frequency ranges become increasingly crowded.To alleviate the above problems, it can be realized dynamic spectrum access
CRSN (Cognitive Radio SensorNetworks, cognition wireless sensor network) come into being.In CRSN, only
Otherwise PU (Primary User, primary user) communication is interfered, sensor node can occupy to chance these idle authorizations
Frequency spectrum (channel).Once PU signal returns, node need to withdraw the frequency range immediately, and find new frequency spectrum access chance.This
In usable spectrum constrained environment, the stability that data are transmitted between node is difficult to be guaranteed, and how to carry out network layer design
Meet the QoS demand of upper layer application, receives more and more attention.
The design of cognition wireless sensor network routing mechanism is usually required the selection of transmission channel and forward node
Selection joins together to consider, to reduce available channel dynamic change to the adverse effect of transmission performance.But this respect at present
Research work is mostly based on：(1) opportunistic frequency spectrum accesses, i.e., waits for an opportunity insertion authority channel when PU is inactive, from time-domain
Frequency spectrum resource is multiplexed；(2) omni-direction transmissions, i.e. node equably emit signal to all directions, be easy to cause to PU compared with
Big interference, to reduce the connectivity of cognition network interior joint.Based on the above two o'clock, it may be considered that answer directional antenna technique
It uses in routing Design, will measure and concentrate on some specific direction being radiated.On the one hand, it advantageously reduces on other directions
Interference to PU further increases the chance of cognition sensor node insertion authority channel from spatial domain.On the other hand, favorably
Hop count is forwarded end to end in expanding the transmission range of signal, reducing, to reduce total delay and the total energy consumption of data transmission.
Chance routing refers to that data packet forwards with carrying out opportunistic using multiple potential both candidate nodes, can further mention
The reliability of high Radio Link.However, can also be opened a gate to while improving authorization frequency spectrum access chance using directional aerial
Routing Design brings no small challenge：(1) due to the limitation of beam angle, when directional aerial is pointed in different directions, node will
Obtain different neighbor node collection；(2) beam angle of directional aerial is narrower, and the transmission range of signal is bigger, is more conducive to subtract
It is small to forward hop count end to end.However, beam angle is narrower, it is meant that signal area coverage is smaller, is unfavorable for obtaining
The forward node of high transformation property；(3) due to the difference in primary user geographical location, the available channel that is detected on different directions
It can be different.
The method that following is a brief introduction of existing cognition routing and directional aerial application：
Liu et al. people proposes that distributed opportunity cognition routes OCR agreement, according to local channel use information and geographical location
Its next-hop is selected independently in information, each intermediate forwarding nodes, to rapidly adapt to the Radio Link of dynamic change.Pan etc.
People proposes that CRSN multichannel machine can route, and when establishing both candidate nodes conflict set, has weighed the contradiction between energy consumption and delivery ratio,
It is intended to obtain delivery ratio as high as possible by consuming less energy.But above-mentioned these routing mechanisms consideration is all
Omni-direction transmissions are not directly applicable the CRSN based on directional aerial.
It is applied to the problems in conventional wireless network routing for by directional aerial, Fang et al. proposes orientation free routing
DART agreement is routed, respectively under two kinds of environment that beam angle is fixed and beam angle can be changed, considers directed routing selection
Problem.Directional aerial and free routing routing are combined by the DSMA that Feng et al. is proposed, and have inquired into antenna direction scheduling
With the Combination selection problem of transmission rate.However, due to the characteristic and sensor node energy of cognitive radio networks itself
Limitation, the method for conventional wireless network routing Design are not fully appropriate for CRSN environment.
Currently, it is relatively fewer that directional aerial is applied to the technology in cognition wireless network, and have focused largely on frequency spectrum sense
Know, channel cross with network connectivity analysis etc..Zhao et al. analyzes the detection probability of frequency spectrum cavity-pocket from angle domain,
Wang et al. is proposed for analyzing the orientation internuncial theoretical model of cognitive self-organizing network.For the ring that PU quantity is excessive
Border, Song et al. proposes that a kind of channel based on directional aerial crosses mechanism, to improve the success rate that cognitive nodes channel crosses.
Dai et al. devises a kind of effective route matrix, by detecting the PU signal on different directions using directional aerial, thus
Judge whether cognitive nodes are in the boundary of PU signal cover, to reduce the interference to it.
By being compared and analyzed to above-mentioned related research result, it is found that at present in CRSN about chance routing with
The co-design scheme that directional aerial is adjusted is relatively fewer, and the utilization of directional aerial is brought to the routing Design under cognitive environment
Advantage it is worthy of further study with research.
Summary of the invention
The technical problem to be solved by the present invention is to：It is passed for finite energy and the cognition wireless of usable spectrum dynamic change
Sensor network provides a kind of effectively chance routing mechanism based on directional aerial, to realize high reliability, low delay, low energy
The data of consumption are transmitted.
The present invention uses following technical scheme to solve above-mentioned technical problem：
A kind of cognition wireless sensor network QoS guarantee chance method for routing based on directional aerial, includes the following steps：
Step (1)：It is adjusted by analysis directional aerial to environment of cognitive radio network interior joint insertion authority frequency spectrum, routing
The influence of node selection, establishes the system model including antenna model and network model；
Step (2)：On the basis of step (1), establishes directional aerial adjusting and combining for cognitron meeting routing Design is excellent
Change mathematical model；It is sector, channel selection, and candidate the two ranks of forward node list creating by combined optimization PROBLEM DECOMPOSITION
Section, and establish corresponding Optimized model；
Step (3)：It is routed using the candidate forward node list that step (2) are established；
Step (4)：Analysis and assessment are carried out to routing performance by Matlab emulation experiment.
Further, the antenna model is established in step (1) of the present invention to specifically include：
Wherein, PrIndicate the reception power of node, PtIndicate the constant power of progress signal transmission, Gt、GrRespectively indicate hair
The antenna gain of machine and receiver is penetrated, l indicates that the distance between two nodes, α are path loss index, and ω is that mean value is zero and mark
Quasi- deviation is the lognormal stochastic variable of σ；
The directional aerial for being θ for beam angle, transmitting or gain G=2 π/θ, the π of 0≤θ≤2 for receiving signal, when adopting
When being received with directional transmissions, omnidirectional, i.e. Gt=G, GrWhen=1, the transmission range r of signal is that formula (2) are shown, correspondingly, signal
Area coverage S is shown in formula (3)：
Wherein, Δ represents the power attenuation between two nodes, Δ=Pt/Pr, ΔtIndicate given power attenuation, when
α、ω、ΔtOne timing, beam angle θ is smaller, and antenna gain G is bigger, and transmission range is remoter, and signal area coverage is smaller.
Further, establishing the network model in step (1) of the present invention is specially：
The holding time of PU in each data channel is assumed to be to the ON/OFF random process for obeying exponential distribution：If ON
State indicates that channel is occupied by PU, and it is respectively z with mean value that OFF state, which indicates channel idle,mAnd umExponential type variable describe
Channel m is in the duration of ON, OFF state, and m ∈ M, M represent one group of data channel, then channel m occupancy or the probability of free time
It is expressed as：
PU motility model is expanded into each sector, is usedIndicate node viIt is in directionBeam angle is the day of θ
The available probability of channel m is detected on line sector.
Further, the connection of directional aerial adjusting with cognitron meeting routing Design is established described in step of the invention (2)
Optimized mathematical model is closed, directional aerial parameter regulation, data channel selection and candidate forward node list creating are specially related to
Combined optimization problem, specially：
If Ti、RiIt indicates to node viThe local delay of single-hop forwarding and reliability requirement,Indicate node viIn side
Xiang WeiBeam angle is the orientation neighbor node set on the sector of θ, candidate forward node listIndicate node viOne group of ordered candidate forward node set on respective sectors and channel m, m ∈
M,N indicates the quantity of candidate forward node, then viSelect data channel, beam sector
It is described as follows with the rule of candidate forward node：
Given：Ti,Ri,M
Find：m*,θ*,
Min：
Subject to：
Wherein, node viSelect local optimum data channel m*, beam directionBeam angle θ*And corresponding candidate turn
Send out listNode energy consumption is minimized while meeting reliability, delay requirement, formula (4) is to minimize energy consumption
Target, condition (5) and condition (6) are to utilize candidate node listCarry out chance forwarding need the reliability that meets and
Delay requirement.
Further, combined optimization PROBLEM DECOMPOSITION is sector, channel selection by step of the invention (2), and candidate turns
Hair node listing creates the two stages, specific as follows：
1., 360 ° of angle domain is divided into N number of antenna sector with fixed beam width and direction, to control sector
Range of choice, each sector crosses over 2 π/N angle, and the direction set expression of these sectors is by θ=2 π/N For present node vi, the mathematical model selected for antenna sector and transmission channel is as follows：
Given:M,
Find:m*,
Maximize:
Subject to:
Wherein,Indicate node viIt is in directionDetect that channel m can be used on the antenna sector that beam angle is θ
Probability, m ∈ M, M represent one group of data channel, m*Indicate selected local optimum data channel,Indicate optimum data channel
The direction of corresponding antenna sector, γ indicate viWith the angle between destination node s, QiIt indicates the thresholding of channel availability, utilizes
Inequality (21) tentatively exclude channel availability lower some channels and antenna sector combination, then using formula (22) come
It determines the antenna sector for data transmission, and selects the highest data channel of availability on the sector；
2., candidate forwarding list is created using heuritic approach, the preferential neighbor node for selecting high priority, once it is full
Sufficient qos requirement, then without selecting more both candidate nodes, wherein the mathematical model for candidate forward node list creating is such as
Under：
Given:m*,Ti,Ri,
Find:
Minimize:
Subject to：
The heuritic approach is created using a kind of method of recursive searchSpecially：
Before search starts,Not comprising any node, every time from neighbor nodeIn select one
A node vj, by its withIn node be added in transient node set F together, and according toSize drop
Sequence arrangement, if the expectation reliability and deferred gratification qos requirement of F, finding out from the neighbor node of these meet demands makes
It must it is expected that energy consumption reaches the smallest node vt, and be added in candidate forwarding list；Otherwise, willMiddle priority
Highest node v1It is put into candidate forwarding list, then above-mentioned ergodic process is repeated from remaining neighbor node, until not having
Remaining optional node or until finding the node listing for meeting QoS demand.
The invention adopts the above technical scheme compared with prior art, has the following technical effects：
1, by applying directional aerial in cognition wireless network, to reduce cognitive nodes to the signal interference of PU, increase
The chance of frequency spectrum access is authorized, further ensures the stability of data transmission in cognition network.
2, by the adjusting of antenna parameter, the creation of the selection of transmission channel and candidate forward node list, it is described as one
The mathematical model of combined optimization, and propose a kind of approximate solution close to optimal solution, realize energy conservation, with QoS guarantee
Data stream transmitting simultaneously effective reduces computation complexity.
3, candidate forward node list being created based on recursive heuritic approach using one kind, complexity is low, high-efficient,
The routing performance close to optimal case can be obtained simultaneously.
4, under equivalent network environment, the chance routing mechanism of the present invention based on directional aerial QoS ensure, handle up
Better than the typically QoS routing plan based on omnidirectional antenna in terms of amount and efficiency.
Detailed description of the invention
Fig. 1 is the frequency spectrum access figure of the present invention based on directional aerial.
Fig. 2 is two kinds of different antenna sector figures of beam angle of the present invention.
Fig. 3 is flow chart of the method for the present invention.
Specific embodiment
Technical solution of the present invention is described in further detail with reference to the accompanying drawing：
Those skilled in the art can understand that unless otherwise defined, all terms used herein (including skill
Art term and scientific term) there is meaning identical with the general understanding of those of ordinary skill in fields of the present invention.Also
It should be understood that those terms such as defined in the general dictionary should be understood that have in the context of the prior art
The consistent meaning of meaning will not be explained in an idealized or overly formal meaning and unless defined as here.
Currently CRSN is directed to time-multiplexed mostly, i.e., cognition sensor node accesses idle award when PU is inactive
Frequency spectrum is weighed, and another possibility scheme for increasing CRSN benefit is exactly to utilize spatial reuse.Directional aerial is as in wireless network
Realize a kind of effective means of spatial reuse, it is possible to reduce signal interference improves the availability of frequency spectrum, this promotes the present invention being based on
Route Selection is unfolded to study in the CRSN of directional aerial.
Refering to what is shown in Fig. 3, process of the invention is as follows：
Step (1), analysis directional aerial adjust the influence to environment of cognitive radio network, mainly include awarding to node access
Weigh the influence of frequency spectrum and routing node selection.
A, directional aerial adjusts the influence accessed to frequency spectrum：
As shown in Figure 1, the omni-direction transmissions range of represented by dashed circles node, solid line sector represents directional transmissions range, letter
Road c1、c2Occupied by primary user.Since sending node cannot cause signal interference to the primary user in its transmission range,
Work as v1When transmitting using omnidirectional antenna, only allow the channel not occupied by primary user using other.On the contrary, if node is using fixed
To antenna transmission, wireless signal can only cover entire sector.Even if v1Busy channel c1The primary user of surrounding will not be caused to do
It disturbs, thus considerably increases the chance of cognitive nodes insertion authority frequency spectrum.
Although the use of directional aerial is that cognitive nodes create more frequency spectrums access chances, in the Route Selection stage
But it needs that suitable antenna direction and beam angle is arranged.Because of the difference in primary user geographical location, if cognitive nodes are determined
It is improper to select to antenna direction, it is also possible to interfere to communicating primary user, to lose the machine of access local channel
Meeting.
B, directional aerial adjusts the influence to Route Selection：
As shown in Fig. 2, the main lobe of directional antenna beams be similar to radius be r sector, θ,Respectively indicate beam angle and
Beam direction.Two different sectors of beam angle, θ ' > θ are given in figure.Compared with narrow beam width, beam angle is got over
Greatly, signal coverage areas is bigger, and obtainable potential forward node is more.However, beam angle is bigger, transmission range is shorter,
The advanced speed of data packet is smaller.On the other hand, beam angle is narrow means that signal transmission distance is remoter, advantageously reduces end and arrives
The forwarding hop count and transmission delay at end.But since the range of choice of forward node is relatively narrow, routing performance is also possible to be damaged.
On the other hand, due to the limitation of beam angle, when antenna beam is pointed in different directions, node will obtain different neighbours
Occupy node set.If antenna direction selection is improper, it is also possible to reduce network transmission performance.
Step (2) establishes system model, including antenna model and network model.
A, antenna model：
Consider that a multichannel CRSN, sensor node are furnished with smart antenna, is capable of providing the two kinds of work of orientation and omnidirectional
Mode.It is imagined as two independent antennas：One single beam antenna that can be turned to and an omnidirectional antenna, by integrated fixed
The antenna system can be realized to transmitter and omnidirectional/direction-finding receiver.Omni-directional mode is mainly used for receiving, and in directional pattern
Under, node can only select the wave beam on some direction, will measure and put together progress signal transmitting or reception.
Usually with antenna gain come the transmission or reception capability of artificial antenna.For beam angle be θ directional aerial and
Speech, transmitting or the gain G=2 π/θ, the π of 0≤θ≤2 for receiving signal.If with constant power PtSignal transmission is carried out, then node
Receiving power can indicate：
Wherein, l indicates the distance between two nodes, Gt、GrIndicate the antenna gain of transmitter and receiver.α is path damage
Index is consumed, under normal conditions 2≤α≤6.ω is the lognormal stochastic variable that mean value is zero and standard deviation is σ, for simulating
The influence of shadow fading effect.In practice, the quality usually transmitted with the power attenuation Δ between two nodes come gauge signal,
Δ=Pt/Pr.The present invention allows power attenuation to be limited in given threshold value ΔtOn, then it can be derived according to formula (1), when using fixed
(G when being received to transmitting, omnidirectionalt=G, Gr=1), the transmission range r of signal is represented by shown in formula (2).Correspondingly, signal
Area coverage S is represented by shown in formula (3)：
As can be seen that working as α, ω, ΔtOne timing, beam angle θ is smaller, and antenna gain G is bigger, and transmission range is remoter, letter
Number area coverage is smaller.
B, network model：
Assuming that there are a common control channel (CCC) and one group of data channel M, CCC between node in the network
The interaction of control message, data channel have all licensed to primary user, and cognition sensor node is not only interfering primary user logical
Under the premise of letter, idle channel therein can be accessed to opportunistic.When source node initiates data communication to its destination node,
Channel access chance is obtained by frequency spectrum perception first, is then selected suitably to forward section in idle channel according to routing mechanism
Point finally completes data transmission.The present invention relates to the chance routings that QoS is ensured, therefore need to select one in relay selection process
Group neighbor node distributes certain priority as candidate forward node, and for these nodes, then according to actual transmissions situation
Next-hop node is selected to chance to carry out data forwarding.By GPS or other positioning devices, its available position of each node
Confidence breath.
Due to the movable randomness of PU, for cognitive nodes, the availability of channel is in spectrum-sensing stage and data
The transmission stage, there may be differences.In order to portray this dynamic variation characteristic of available channel, the present invention believes each data
The holding time of PU is assumed to be the ON/OFF random process for obeying exponential distribution in road：ON state indicates that channel is occupied by PU；OFF
State indicates channel idle.It is respectively z with mean valuemAnd umExponential type variable to describe, channel m is in ON, OFF state continues
Time, m ∈ M, then channel m is occupied or the probability of free time is represented by：With It is more careless
Taste channel m it is more stable, more suitable for data transmit.In view of channel availability of the node on each antenna sector
It is dynamically that PU motility model is expanded to each sector by the present invention, usesIndicate node viIt is in directionBeam angle
To detect the available probability of channel m on the antenna sector of θ.
Step (3), the combined optimization mathematical model for establishing directional aerial adjusting and chance routing Design
The present invention inquires into a kind of cognition wireless sensor network QoS guarantee chance routing DAOR based on directional aerial, leads to
Available channel information, the localized network status information etc. arrived using node perceived is crossed, which is meeting the same of QoS constraint condition
When, realize the low energy consumption transmission of data flow.The combined optimization problem of directional aerial adjusting and chance Route Selection is described first,
Then link standard and energy model are provided, ultimate analysis reliability and delay require.
The description of combined optimization problem：
Unlike the routing of conventional wireless network chance, cognitive nodes must determine that it transmits day before transmitting data
Line sector (being determined by antenna direction and beam angle), data channel and candidate forward node.Sensor network is applied to QoS's
Demand, without loss of generality, the present invention consider time delay and two kinds of demands of reliability.Due to the dynamic characteristic of wireless medium, it is impossible to
Obtain real-time, accurate end-to-end link state.Therefore, end-to-end QoS demand is divided into and needs to single-hop QoS by the present invention
It asks, if meeting the requirement of each jump, QoS will be substantially achieved guarantee end to end.
If Ti、RiIt indicates to node viThe local delay of single-hop forwarding and reliability requirement,Indicate node viIn side
Xiang WeiBeam angle is the orientation neighbor node set on the sector of θ, candidate forward node listIndicate node viOne group of ordered candidate forward node set on respective sectors and channel m,Then viSelect the rule of data channel, beam sector and candidate forward node
It is described as follows：
Given：Ti,Ri,M
Find：m*,θ*,
Min：
Subject to：
Node viSelect local optimum data channel m*, beam directionBeam angle θ*And corresponding candidate forwarding listNode energy consumption can be minimized while meeting reliability, delay requirement.Formula (4) is to minimize energy consumption mesh
Mark, condition (5) and condition (6) are to utilize candidate node listCarry out chance forwarding need the reliability that meets and when
Prolong requirement.
Neighbours' discovery：
As shown in Fig. 2, with (xi,yi)、(xj,yj) indicate node v in planeiWith node vjGeographical coordinate, then they it
Between Euclidean distance d (vi,vj) and angle β be represented by：
If the distance between two nodes are less than or equal to directional transmissions distance, d (i, j)≤r, and its angle and are no more than wave beam
Boundary,Illustrate node vjFall in viSignal cover in, note
In conventional wireless network, can establish if two nodes fall into mutual transmission region, between them one it is logical
Believe link.Communication link can be formed but in wireless cognition network, between two nodes and depends not only on signal transmission ranges, also
Depending on spectrum availability.When meeting following two condition, node viAnd vjBetween can establish communication link：(1)
viAnd vjEach fall within mutual transmission region, i.e. vi、vjNeighbor node each other；(2)viAnd vjWith public available channel, this meaning
Taste in node-node transmission region be not present active primary user.
Energy loss：
According to the energy model in existing document it is found that if node viAnother node-node transmission to except l distance
The data packet of Lbit, then transmitting energy consumption is：
Et,i=Eelec·L+εamp·lα·L (9)
Wherein, EelecIndicate that transceiver circuit sends or receives energy consumed by 1bit data, εampIndicate power amplification
The operating power consumption of device, α are path loss index.In view of packet loss problem present in data transmission procedure, node vjIt may be only
It receivesThe data packet of bit, whereinIndicate node vi、vjBetween delivery ratio of the link on channel m, then receive energy
Consumption is represented by：
Assuming that node only monitors the transport behavior for being sent to oneself, and energy loss is mainly used for the transmission of data and connects
It receives.In order to investigate the influence that primary user's activity communicates node, invention defines a new indexs to assess Node station meeting
Energy consumption it is expected in the cognition of forwarding, as shown in formula (11).Wherein, n indicates the quantity of candidate forward node,
Reliability Assurance：
Using data packet delivery fraction, that is, the data packet for being successfully transferred to destination node accounts for total percentage for sending data packet and comes
Assess the reliability of link.If it is desired to every hop link on path provides same reliability, then node viSelect both candidate nodes
The local delivery rate met needed for list can be estimated as：
Wherein, Ri,sAnd HiIt respectively indicates from viTo the reliability requirement between destination node s and it is expected transmission hop count, i.e.,：
Wherein,It indicates from source node to present node viAverage single-hop forward travel distance.
Definition expectation delivery ratioForIn at least exist a both candidate nodes be successfully received node
viThe probability of the data packet of transmission, since the packet loss event of different chain roads is mutually indepedent, thenIt is represented by：
Delay Guarantee：
Proposed by the present invention is the routing algorithm based on frequency spectrum perception, and in each jump data transmission procedure, node is first had to
Idle channel is detected, idle channel transmitting data information is then utilized.After receiving data packet, both candidate nodes then according to setting in advance
The time of evading set replys confirmation message ACK.Priority is higher, and it is shorter to evade the time, more first replys.Sending node is once received
It is replied to ACK, then broadcast is completed to receive message CTR on CCC, to notify other both candidate nodes sender has received ACK to disappear
Breath repeats to forward to reduce unnecessary data packet.Assuming that node vjIt is the both candidate nodes that priority comes jth position, Then utilize node vjThe single-hop delay of forwarding data is mainly represented by：
ti,j=tS+tDATA+tW (15)
Wherein, tS、tDATAIndicate channel perception and data transmission delay, tWIndicate mutually coordinated time delay between both candidate nodes,
tW=j (2 μ+tACK+tCTR), i.e., node waits the time for replying ACK after receiving data packet.μ indicates minimum short frame slot
Interval, tACK、tCTRRespectively indicate the time for replying ACK, CLR message.
Data transmission delay constraint substantially also can be regarded as the space-time restriction of data packet migration, so the present invention utilizes
Mechanism based on geographical location estimates the requirement to single-hop delay by the limitation to advanced speed：
Wherein, Ti,sIt indicates from viDelay requirement between destination node s,It is utilized respectivelyExpectation forward travel distance and the expectation delay for carrying out opportunistic forwarding, as shown in formula (18) and (19).aij=d (vi,
s)-d(vj, s), indicate node viTo each both candidate nodes vjForward travel distance,
It needs to consider factors in the process for carrying out routing Design and adjusting directional aerial parameter, relies solely on single finger
It is impossible that mark, which obtains best solution,.Next, it is above-mentioned in relation to routing choosing to simplify to introduce a kind of approximate schemes
Select the combined optimization problem with antenna adjustments.
Step (4)：For combined optimization problem described in step (3), a kind of approximation solution close to optimal solution is proposed
Scheme.
Theoretically the variation space of antenna direction and beam angle is continuous, can thus there is infinite mutiple antennas fan
Area is available, but directional aerial can not be designed to such complexity in real life, and carry out under each sector
Exhaustive search is also unpractical to find best solution.Therefore, 360 ° of angle domain is divided into and has by the present invention
N number of antenna sector of fixed beam width and direction, to control the range of choice of sector.2 π/N angle, θ are crossed in each sector
The direction set expression of=2 π/N, these sectors isFor each node, antenna sector
Beam angle is fixed, so only it needs to be determined that the direction of sector.
It is exactly to obtain optimal data channel, transmission sector and corresponding candidate forwarding list, most intuitive method
Carry out exhaustive search：All data channels are combined with sector directions, for each combination, traverse the institute of neighbor node
There is subset, filters out and not only meet QoS demand, energy loss but also least forward node list.If | M |=C,
Then one is sharedKind selection.When N, C or n are very big, this is limited energy and processing capacity
It is unpractical for CRSN.In order to reduce the complexity of calculating, it is necessary to design an approximation close to optimal solution and solve
Scheme.
Therefore optimization problem is decomposed into two stages by the present invention：Firstly, determining forwarding sector and transmission channel；Secondly,
Under selected antenna sector and data channel, building had not only met QoS demand, energy loss but also least forward node list.
The selection of antenna sector and data channel：
In the chance forwarding routing based on geographical location, often selected using the forward travel distance of node as next-hop
Index, to approach Shortest path routing.If the antenna sector for being directed toward destination node can be selected, before inevitably facilitating acquisition
Into apart from biggish forward node, to increase the advanced speed of data packet, reduce transmission delay.But only according to antenna
Direction come select transmission sector, do not ensure that the channel availability with higher on the sector.Channel availability is poorer, recognizes
A possibility that knowing the communication link acceptor customer impact between node and interrupting is bigger, will lead to number of retransmissions and increases.Another party
Face, if the present invention follows the principle of maximum channel availability simply to select antenna sector and communication channel, having very much can
Can cause the transmission path of selection it is longer, delay it is bigger.
In short, one suitable antenna sector of selection and transmission channel depend not only on sector directions, the fan is additionally depended on
Channel availability in area.Therefore, the present invention devises the selection scheme of a kind of practical joint sector and channel, it is therefore intended that
Transmission cost is reduced as much as possible, while the guarantee of high channel availability being provided.For present node vi, antenna sector and data
The selection rule of channel is as follows：
Given:M,
Find:m*,
Maximize:
Subject to:
Wherein, γ indicates viWith the angle between destination node s, QiIndicate the thresholding of channel availability.Utilize inequality
(21), the combination of channel availability lower some channels and antenna sector can be tentatively excluded, then on this basis, is utilized
Formula (22) is determined for the antenna sector of data transmission, and selects the highest data channel of availability on the sector.
Next, the present invention will set the threshold value Q of channel availability using the thought of probability guaranteei, that is, allow
Probability be not less than λ, be expressed as：
It enablesThen formula (23) can be exchanged into：
The mean μ and variances sigma of given stochastic variable X2, according to unilateral Chebyshev inequality, meet condition：
By the way that Chebyshev inequality is applied to formula (24), it can be deduced that：
Wherein,WithRespectively indicate variableMean value and variance.According to the transmitting of inequality (24) and (26)
Property, if meeting condition
Probability guarantee can will be then obtained with availability defined in formula (23).Corresponding threshold value can be set to：
Create the heuritic approach of candidate forward node list：
Using given antenna sector and data channel, next needs to select candidate forward node and distribute for it preferential
Grade.In general, if distributing priority according to the single-hop forward travel distance of both candidate nodes, it is expected that forward travel distance gain is incited somebody to action
To maximization.If distributing priority according to data packet delivery fraction, desired transmission delay can be reduced.In view of dynamic
Wireless link environment in, signal transmission distance is remoter, and data packet delivery fraction is lower.Therefore the present invention uses a kind of plan of compromise
Slightly, it utilizesTo distribute priority for candidate forward node.The selection rule of candidate forward node is as follows：
Given:m*,Ti,Ri,
Find:
Minimize:
Subject to：
In order to obtain optimal forward node list, intuitive method is exactly exhaustive search, but this can bring higher meter
Complexity is calculated, it is for the sensor node that energy is limited with processing capacity and improper.In addition, candidate forwarding list is not yet
Preferably include too many node because energy consumption and coordinate delay cost also can with the increase of candidate forward node quantity and
Increase.Therefore the present invention devises a kind of effective heuritic approach to create candidate forwarding list, the preferential high priority that selects
Neighbor node, once meet qos requirement, then without selecting more both candidate nodes.
The implementation procedure of algorithm is as shown in algorithm 1, and wherein h indicates the maximum quantity of candidate forward node.Algorithm uses one
The method of recursive search is planted to createBefore search starts,Not comprising any node.Every time from
Neighbor nodeIn select a node vj, by its withIn node be added to transient node set F together
In, and according toSize descending arrangement.If the expectation reliability and deferred gratification qos requirement of F, from these satisfactions
It is found out in the neighbor node of demand so that it is expected that energy consumption reaches the smallest node vt, and be added in candidate forwarding list.
Otherwise, willThe node v of middle highest priority1It is put into candidate forwarding list, is then repeated from remaining neighbor node
Above-mentioned ergodic process, until no remaining optional node or until finding the node listing for meeting QoS demand.WhenThe time complexity of algorithm 1 is O (n2).If scanned for using enumeration, time complexity O
(n！).It can be seen that once n becomes very large, heuritic approach will be more more efficient than exhaustive search.
Those skilled in the art can understand that can realize these structure charts with computer program instructions
And/or the combination of each frame and these structure charts and/or the frame in block diagram and/or flow graph in block diagram and/or flow graph.It can be with
These computer program instructions are supplied to the processing of general purpose computer, special purpose computer or other programmable data processing methods
Device generates machine, creates to be performed instruction by the processor of computer or other programmable data processing methods
For realizing the method specified in the frame or multiple frames of structure chart and/or block diagram and/or flow graph.
Those skilled in the art can understand that the various operations crossed by discussion in the present invention, method, process
In step, measure, scheme can be replaced, changed, combined or be deleted.Further, there is in the present invention mistake by discussion
Various operations, method, other steps, measures, and schemes in process can also be replaced, change, reset, decomposing, combining or
It deletes.Further, it is in the prior art have in various operations, method disclosed in the present invention, process step, arrange
It applies, scheme may also be alternated, changed, rearranged, decomposed, combined or deleted.
Embodiments of the present invention are explained in detail above in conjunction with attached drawing, but the invention is not limited to above-mentioned
Embodiment within the knowledge of a person skilled in the art can also be before not departing from present inventive concept
It puts and makes a variety of changes.
Claims (6)
1. a kind of cognition wireless sensor network QoS based on directional aerial ensures chance method for routing, it is characterised in that including
Following steps：
Step (1)：It is adjusted by analysis directional aerial to environment of cognitive radio network interior joint insertion authority frequency spectrum, routing node
The system model including antenna model and network model is established in the influence of selection；
Step (2)：On the basis of step (1), the combined optimization number of directional aerial adjusting with cognitron meeting routing Design is established
Learn model, combined optimization problem be further broken into sector and channel selection, and candidate forward node list creating this two
A stage, and establish corresponding Optimized model；
Step (3)：It is routed using the candidate forward node list that step (2) are established.
2. the cognition wireless sensor network QoS according to claim 1 based on directional aerial ensures chance method for routing,
It is specifically included it is characterized in that, establishing the antenna model in step (1)：
Wherein, PrIndicate the reception power of node, PtIndicate the constant power of progress signal transmission, Gt、GrRespectively indicate transmitter
With the antenna gain of receiver, l indicates the distance between two nodes, and α is path loss index, and ω is that mean value is zero and standard deviation
Difference is the lognormal stochastic variable of σ；
The directional aerial for being θ for beam angle, transmitting or gain G=2 π/θ, the π of 0≤θ≤2 for receiving signal, when using fixed
When being received to transmitting, omnidirectional, i.e. Gt=G, GrWhen=1, the transmission range r of signal is shown in formula (2), and correspondingly, signal covers
Area S is shown in formula (3)：
Wherein, Δ represents the power attenuation between two nodes, Δ=Pt/Pr, ΔtIndicate given power attenuation, when α,
ω、ΔtOne timing, beam angle θ is smaller, and antenna gain G is bigger, and transmission range is remoter, and signal area coverage is smaller.
3. the cognition wireless sensor network QoS according to claim 1 based on directional aerial ensures chance method for routing,
It is characterized in that, establishing the network model in step (1) and being specially：
The holding time of PU in each data channel is assumed to be to the ON/OFF random process for obeying exponential distribution：If ON state
Indicate that channel is occupied by PU, it is respectively z with mean value that OFF state, which indicates channel idle,mAnd umExponential type variable channel m described
Duration in ON, OFF state, m ∈ M, M represent one group of data channel, then channel m is occupied or the probability of free time indicates
For：
PU motility model is expanded into each sector, is usedIndicate node viIt is in directionThe antenna that beam angle is θ is fanned
The available probability of channel m is detected in area.
4. the cognition wireless sensor network QoS according to claim 1 based on directional aerial ensures chance method for routing,
It is characterized in that, the combined optimization mathematical model of directional aerial adjusting with cognitron meeting routing Design is established described in step (2),
Specially it is related to the combined optimization problem of directional aerial parameter regulation, data channel selection and candidate forward node list creating,
Specially：
If Ti、RiIt indicates to node viThe local delay of single-hop forwarding and reliability requirement,Indicate node viIt is in directionBeam angle is the orientation neighbor node set on the sector of θ, candidate forward node listTable
Show node viOne group of ordered candidate forward node set on respective sectors and channel m, m ∈ M,N indicates the quantity of candidate forward node, then viSelect data channel, beam sector and
The rule of candidate forward node is described as follows：
Given：
Find：
Min：
Subject to：
Wherein, node viSelect local optimum data channel m*, beam directionBeam angle θ*And corresponding candidate forwarding listNode energy consumption is minimized while meeting reliability, delay requirement, formula (4) is to minimize power dissipation obj ectives, item
Part (5) and condition (6) are to utilize candidate node listCarrying out chance forwarding needs the reliability met and time delay to want
It asks.
5. the cognition wireless sensor network QoS according to claim 4 based on directional aerial ensures chance method for routing,
It is characterized in that, combined optimization PROBLEM DECOMPOSITION is sector, channel selection, and candidate forward node list creating by step (2)
It is the two stages, specific as follows：
1., 360 ° of angle domain is divided into N number of antenna sector with fixed beam width and direction, to control the choosing of sector
Range is selected, 2 π/N angle is crossed in each sector, and the direction set expression of these sectors is by θ=2 π/N For present node vi, the mathematical model selected for antenna sector and transmission channel is as follows：
Given:
Find:
Maximize:
Subject to:
Wherein,Indicate node viIt is in directionDetect that channel m is available general on the antenna sector that beam angle is θ
Rate, m ∈ M, M represent one group of data channel, m*Indicate selected local optimum data channel,Indicate that optimum data channel institute is right
The direction of antenna sector is answered, γ indicates viWith the angle between destination node s, QiThe thresholding for indicating channel availability, using differing
Formula (21) tentatively excludes the combination of channel availability lower some channels and antenna sector, is then determined using formula (22)
For the antenna sector of data transmission, and select the highest data channel of availability on the sector；
2., candidate forwarding list is created using heuritic approach, the preferential neighbor node for selecting high priority, once meet
Qos requirement, then without selecting more both candidate nodes, wherein the mathematical model for candidate forward node list creating is as follows：
Given:
Find:
Minimize:
Subject to：
The heuritic approach is created using a kind of method of recursive searchSpecially：
Before search starts,Not comprising any node, every time from neighbor nodeIn select a section
Point vj, by its withIn node be added in transient node set F together, and according toSize descending row
Column, if the expectation reliability and deferred gratification qos requirement of F, found out from the neighbor node of these meet demands so that the phase
Energy consumption is hoped to reach the smallest node vt, and be added in candidate forwarding list；Otherwise, willMiddle highest priority
Node v1It is put into candidate forwarding list, then above-mentioned ergodic process is repeated from remaining neighbor node, until not remaining
Optional node or until finding the node listing for meeting QoS demand.
6. the cognition wireless sensor network QoS according to claim 1 based on directional aerial ensures chance method for routing,
It is characterized in that, further including step (4)：Analysis and assessment are carried out to routing performance by Matlab emulation experiment.
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