CN104683987B - Transmission dispatching method of the SVC videos in cognitive radio multichannel - Google Patents
Transmission dispatching method of the SVC videos in cognitive radio multichannel Download PDFInfo
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Abstract
The present invention proposes a kind of transmission dispatching method of SVC videos in cognitive radio multichannel, on the one hand methods described provides dynamic spectrum access scheme of the mechanics for considering primary user based on Flexible timeslot, unnecessary channel detection is reduced, further increases the utilization rate of wireless signal-path band width；On the other hand the present invention also provides a SVC video and the multi channel graduation matching strategy of cognitive radio, pass through the priority of reasonable distribution SVC video datas, the transmission order of arrangement SVC video datas and SVC video datas and the multi channel dynamic adaptation of cognitive radio, the SVC data that importance is higher in a long term time frames are enabled to be transmitted by the higher radio channel resource of reliability, the relatively low SVC video datas of importance are transmitted by the relatively low channel resource of reliability.Optimized by both sides, make more video data Successful transmissions, and the validity of the video data received is higher, the quality for the video that final optimization pass receives.
Description
Technical field
The invention belongs to Video coding and transmission field, and in particular to a kind of SVC videos are in cognitive radio multichannel
Transmission dispatching method.
Background technology
Video Applications in wireless environment are increasingly favored by user, but this also brings problems simultaneously.It is first
First, it is understood that a video traffic can in most cases take more channel moneys than common audio and text services
Source, the wireless terminal emerged in multitude to video traffic request also cause wireless environment in video flow proportion and regard
The total amount of frequency stream is increasing, therefore radio spectrum resources also just seem relative scarcity.Secondly, wireless channel is by surrounding environment
Have a great influence, radio link quality there are larger time-varying characteristics, and then video flowing is preferably adapted to the wireless of this time-varying
Channel is a very big challenge.Again, wireless terminal species is various, and its resolution ratio, disposal ability, power reservoir capacity all may be poor
Often it is difficult to directly be adapted to a variety of wireless terminals away from larger, single video source.Problems also promote wireless ring
The development of transmission of video correlative study in border.
Cognitive radio (Cognitive Radio, CR) is a kind of by frequency spectrum perception and system intelligence learning, to realize
The dynamically distributes of frequency spectrum and the technology of frequency spectrum share.It finds sky therein on the basis of mandate frequency range proper communication is not influenceed
Ideler frequency is composed and rationally utilizes these frequency spectrums.CR improves the frequency spectrum caused by the fixed allocation policy of frequency spectrum and provided to a certain extent
The low present situation of source utilization rate, alleviate the situation of radio spectrum resources relative scarcity.There are primary user and secondary in CR networks
Point of user, secondary user's detect the state of multiple channels, and only could access channel and transmit number there is channel idle
According to.More dynamic spectrum access schemes using fixed time slot in existing research, i.e. a time slot include a fixed detection
Duration and a fixed transmission duration, and only when according to result of detection judge channel for it is idle when, channel can be accessed
And transmit data.The access scheme of this fixed time slot does not have the specific mechanics for considering primary user corresponding to channel, because
This is possible to cause many unnecessary frequent detections, and this reduces the utilization rate of channel width.Some research considerations pass through
Adaptive adjustment detection duration reduces unnecessary channel detection with transmission duration, so as to improve the utilization rate of channel width.
These mostly researchs are optimized for single channel, without mutually coordinated between the multiple channels of consideration, therefore each letter
Detection period and the arrangement of the separation of transmission period in road will have no rule.When a secondary user's monitor multiple letters simultaneously
During road, secondary user's need to judge channel status at detection period with transmission period separation, and whether decision-making accesses, sends
Which type of data.It is difficult that arrival is optimal that the data for causing secondary user's are assigned decision-making by this irregular decision point arrangement.
" opportunism " access way that this wait idle channel of secondary user's occurs causes the available of secondary user's
Bandwidth changes greatly.The problem of unstability of bandwidth has been aggravated in first paragraph to a certain extent two, i.e. packet loss are sensitive to be regarded
The multichannel that frequency business is preferably adapted in CR networks will be more difficult.Telescopic video compared with other non-telescopic videos more
Adapt to the unstable CR network multiple-channel scenes of this network condition.Using the Scalable Video of layered encoding structure
Coding（SVC）All there is scalability in three time, space and quality dimensions, it can by a video frequency source coding into
One SVC video flowing for including multiple subflows, each of which subflow can reconstruct a source video, simply in time, sky
Between or the resolution ratio of quality on have difference.SVC telescopic nature causes the video anti-packet loss ability of coding to protrude, even if
In network condition, still heat energy accesses relatively good video quality in poor and unstable wireless network.
Some existing researchs further transmission of the optimization telescopic video in cognitive radio networks, but these grind
It is to apply the Inherent advantage of telescopic video to study carefully work, and the flexible configuration without can further excavate telescopic video exists
Video is improved to the effectiveness in the adaptability of channel.
The content of the invention
It is an object of the present invention to overcome above mentioned problem, by further optimizing the dynamic in cognitive radio technology
Frequency spectrum access scheme improves channel bandwidth utilization ratio, and this is larger to promoting the development of the larger wireless video business of bandwidth consumption to have
Benefit；On the other hand employ the SVC videos for having preferable adaptability to channel, go forward side by side one-step optimization SVC videos to time-varying,
The multi channel adaptability of the different cognitive radio of reliability, the quality of final optimization pass receiving terminal video.
To reach above-mentioned purpose, the present invention provides a kind of transmission of SVC videos in cognitive radio multichannel environment and adjusted
Degree method, methods described include：Channel first for the detection of some secondary user's defines the flexible factor, and the flexible factor is used to retouch
State the slot length of channel；Then, each channel detected based on the flexible factor and primary user's mechanics it is optimal flexibly
The factor；Finally, when judging that channel that user has access to and user access the transmission of some channel according to the optimal flexibly factor
The length of gap.
Optionally, above-mentioned transmission dispatching method comprises the following steps：
Step 101）Secondary user's are in TsThe free time of the N number of wireless channel of detection or busy condition, then define N in period
The slot length of each channel in individual channel is θ times of a fixed slot length, and the θ is the flexible factor；
Step 102）
The mechanics model of primary user is established, obtain primary user according to model keeps idle condition within certain section of period
Or the probability of busy condition, and obtain primary user within this time by it is busy be converted to the free time or by free time be converted to it is busy
Probability；
The probability of idle condition or busy condition, primary user is kept to be converted to sky by busy based on the flexible factor, primary user
Collision probability that is not busy and being changed into busy probability, acquisition secondary user's and primary user by the free time；
Collision probability according to secondary user's and primary user be no more than primary user patient maximum crash probability original
Then, the optimal flexible factor of each channel in N number of channel is calculated
Step 103）Available channel using optimal channel of the flexibly factor more than or equal to 1 as secondary user's, and it is all
The number of available channel is G, and wherein G is less than or equal to N；
Step 104）Secondary user's are accessed into available channel, the SVC video datas of secondary user's are sent using G channel,
Return to step 101）, until all data of secondary user's are sent completely；
Wherein, the duration of the channel n progress SVC video data transmissions in G idle channel of secondary user's access isThe fixed slot length is " Ts+Tt", TtFor the period of a fixed size.
In such scheme, the calculation formula of any one channel n optimal flexibly factor is as follows：
Wherein,The probability to be collided for secondary user's and primary user in channel n,For primary user on channel n
Patient maximum collision probability, the channel n be N number of channel in some channel.
Optionally, it is above-mentionedCalculation formula be：
Wherein,Represent channel n in SEThe probability of free time at moment, and SEFor secondary user's sounding channel detection when
Section TsThe ending moment.
Optionally, obtainThe step of be：
Step 201）The step of obtaining primary user's mechanics model, it is specially：
The mechanics of primary user obeys continuous time Markov model, i.e., between the free time of primary user and busy condition
Transfer obey Markov characteristic, while the duration of " busy and idle " two states of primary user obey respectively it is as follows
Quantum condition entropy, obtain following quantum condition entropy and obtain primary user's mechanics model：
Above-mentioned fI(t) represent the probability density function of primary user's free time in channel n in the value of t, αnValue root
It is believed that the historical data of primary user's activity obtains in road n, the value is equal to the phase that primary user in channel n is in the duration of idle period
The inverse of prestige value；
fB(t) represent the busy probability density function of primary user in channel n in the value of t, βnValue be equal to root
It is believed that the historical data of primary user's activity obtains in road n, the value is equal to the phase that primary user in channel n is in the duration of busy period
The inverse of prestige value；
Step 202）According to the mechanics model of obtained primary user, exist according to equation below prediction（0, ε）Period
It is interior, the idle or busy probability of channel n shared by primary user：
Wherein, FI(ε) and FB(ε) is respectively primary user keeps idle shape within the period from the moment of t=0 to t=ε moment
The probability of state and busy condition；“1-FI(ε) " is that primary user is transformed to out of t=0 moment to the period at t=ε moment by the free time
Busy probability；1-FB(ε) be primary user out of t=0 moment to the period at t=ε moment by the busy probability for being transformed to the free time；
Step 203）Defining actual idle probability of the channel n in the detection finish time SE of secondary user's is：
Wherein, detection period of the secondary user's to channel n is from SBMoment, to SEMoment terminates；RS is that secondary user's exist
Moment, i.e. S are completed in the detection to channel n every timeEAt the moment, obtain a result of detection, and it is empty that RS=0, which represents the result of detection,
Not busy state, RS=1 represent the result of detection as busy condition；γnThe probability occurred for false-alarm, i.e., be idle shape when channel is actual
State, i.e. AS=0, but result of detection is busy, i.e. RS=1；δnThe probability occurred for false dismissal, i.e., be busy condition when channel is actual,
That is AS=1, but result of detection is idle condition, i.e. RS=0；
Step 204）According to FI(ε)、FB(ε)、1-FI(ε) and 1-FB(ε) obtains P（AS=0）And P（AS=1）Value, specifically
For：
Wherein,It is channel n in SBMoment actual idle probability, the probable value rely on SBUpper one before moment
Individual non-slotted channel n state；When in SBSecondary user's success before in channel n transmits data, then it is assumed that idle general of channel n
Rate isWhen in SBSecondary user's think that the idle probability of channel n is before after being collided with primary userWhen secondary user's do not transmit data in the channel, then the channel after the period can be detected according to a upper time slot
Idle probability calculates, andPrediction equation it is as follows：
Represented a upper detection time slot finish times of the channel n in secondary user'sWhen idle probability；
Channel n state is represented respectively in transmission duration TtIt is interior to keep idle probability and from busy conversion
To the probable value of free time.
Optionally, step 104）The step of SVC video datas of described transmission secondary user's, further includes：
Step 104-1）SVC video datas are set into priority and the starting point and cut off of each frame are set, positioned at starting
NALU in the range of point and cut off is effective, and effective NALU is placed on according to priority and sent in buffering area；
Step 104-2）Will send buffer area in each NALU split encapsulation, and will split encapsulation packet transmission with
G idle interchannel carries out dynamic adaptation, so as to which the packet of more high priority is used into the more reliable channel of channel performance
It is transmitted.
Optionally, above-mentioned steps 104-1）Further include：
Step 104-1-1）The SVC video datas for encoding to obtain using GOP are subjected to following principle and carry out priority stroke
Point：
It is higher to set the priority of the frame that time stratum level is lower in a GOP, and multiple time stratum levels are identical
Frame in playing sequence it is more early frame priority it is higher；
And meet：
Mass segregation lower grade NALU priority is higher in a frame in one GOP；
And meet：
The priority of all NALU in one GOP in a certain mass segregation grade, it is overall to be higher than positioned at more high-quality
The priority of all NALU on stratum level is measured, and less than positioned at the preferential of all NALU more on low quality stratum level
Level；
Step 104-1-2）According to the transmission order of all frames in one GOP of priority level initializing of definition, and in the GOP
Each frame distributes a starting point and a cut off, when being sometime between the starting point of some frame and cut off,
Then all NALU in the frame are effective, and these effective NALU are arranged according to the priority of definition in buffering area is sent
Sequence；
Wherein,
When cut off reaches, the NALU data sent in buffering area but not yet will be disabled and abandon, and open
Effective NALU in next GOP is put into buffering area by the beginning；
The setting principle of above-mentioned starting point and cut off is：Time difference between adjacent two frames starting point is normally broadcast equal to two frames
Time interval when putting；And all frames share same cut off in a GOP, the shared cut off is next
The starting point of the first frame included in GOP.
Optionally, above-mentioned steps 104-2）Further include：
Step 104-2-1）The collection that the available channel for detecting to obtain by the secondary user's when in certain decision-making is formed
It is combined into C={ c1,c2,...,cg,...,cG, and the decision-making moment positioned at send buffering area in NALU set expression for Φ=
{φ1,φ2,...,φk,...,φK}；
Wherein, φk＜ φk+1, i.e., index is φkNALU priority be more than index be φk+1NALU priority；
Step 104-2-2）The descending of NALU priority in buffering area is sent according to above-mentioned detection moment, is maximized successively
Each element φ in NALU setkThe probability for successfully being received and being decoded, finally give and send the optimal of video source data
Send and arrange vector；
Wherein, will enter according to optimal vector positioned at the NALU sent in buffering area with the channel in available channel set C
Row matching.
Optionally, above-mentioned steps 104-2-2）Determine that optimal transmission arranges vector using equation below
Wherein,
It is above-mentionedRepresent that index is φkNALU be successfully received and the probability that can decode,Represent bagPress
According toPacket loss of link probability in the case of arrangement,Represent bagAccording toThe feelings of arrangement
Collision drop probabilities under condition,Represent that by index be φkNALU carry out splitting the index of each bag that encapsulation obtains, k
Span be 1≤k≤K '.
Optionally, optimal vector is obtained using greedy algorithmValue, be specially：
When set of available channels is C={ c1,c2,...,cg,...,cG, send buffering area in NALU set Φ=
{φ1,φ2,...,φk,...,φKWhen：
Step 301）By optimal vectorIt is initialized as：Wherein,Represent empty set；
Step 302）Each NALU sent in buffering area in effective NALU set Φ is split into simultaneously package；
Step 303）Judge send in buffering area whether have the bag not sent, if entering step 304）；Otherwise enter
Enter step 306）；
Step 304）Judge whether there is available channel resource in set C, if then entering step 305）；Otherwise enter
Step 306）；
Step 305）Send to take out in buffering area from data and come most preceding bag（Highest priority), it is assumed that for bagSuccessful transmissions probability when calculating it respectively remaining available channel being transmitted in set C；
Selection can provide the transmission arrangement of the channel and specific package location of maximum Successful transmissions probability as the bag, such as position
Put (cg,q)；
It will arrangeIt is added to setIn,It isIn an element；
Update in set C in remaining available channel information and channel specifically remaining available volume of resources information；Renewal is sent
Remaining packet information to be sent in buffering area Φ；Return to step 303）；
Step 306）Obtain SVC data and the best fit strategy of Wireless Multi-Channel
Compared with prior art, the technical advantages of the present invention are that：
First, the present invention proposes a kind of dynamic spectrum access side of Flexible timeslot using the mechanics of primary user as foundation
Case, this scheme improve not still in order to improve the utilization rate of channel width, and consider the coordination between CR multichannels
Secondary user's distribute the validity of data in CR multichannels.Secondly, the present invention is with the dynamic spectrum access scheme of Flexible timeslot
Based on, devise a SVC video and the multi channel graduation matching strategies of CR.A consideration data are included in the strategy
The ageing scheme that data transmission arrangement is carried out with priority orders, it is contemplated that may have multiple reliability phases during each decision-making
The larger available channel of difference, the importance that the program to send the data in buffering area during decision-making also have larger gap, this
Allow for the more important data in long-term to can be transferred through relatively reliable channel and be transmitted to be possibly realized, receive the matter of video
Amount also can further be optimized.
Brief description of the drawings
Fig. 1 is the dynamic spectrum access scheme exemplary plot of the fixation time slot of prior art；When Sense represents detection in the figure
Section, IDLE represent idle condition, and BUSY represents busy condition；
Fig. 2 is that transmitting and scheduling of the SVC videos provided by the invention in cognitive radio multichannel environment performs flow
Rough schematic；
Fig. 3 is SVC videos provided by the invention and the multi channel matching schematic flow sheet of available cognitive radio；
Fig. 4 is the dynamic spectrum access scheme exemplary plot of the Flexible timeslot of the present invention；When Sense represents detection in the figure
Section, IDLE represent idle condition, and BUSY represents busy condition；
Fig. 5 is SVC data priorities allocation example figure of the present invention；
Fig. 6（a）With 6（b）It is the coded sequence and transmission order example of SVC frame of video of the present invention；
Fig. 7 is that the priority orders data of the consideration data age of the embodiment of the present invention send arrangement scheme exemplary plot.
Embodiment
The method of the invention is described in detail with reference to the accompanying drawings and examples.
First, the dynamic spectrum access scheme provided by the invention based on Flexible timeslot is as described below：
A kind of transmission dispatching method of the SVC videos provided by the invention in cognitive radio multichannel environment, the side
Method includes：
Step 101）Secondary user's are in TsThe free time of the N number of wireless channel of detection or busy condition, then define N in period
The slot length of each channel in individual channel is θ times of a fixed slot length, and the θ is the flexible factor；
Step 102）
The mechanics model of primary user is established, obtain primary user according to model keeps idle condition within some period
Or the probability of busy condition, and obtain primary user within this time by it is busy be converted to the free time or by free time be changed into it is busy
Probability；
The probability of idle condition or busy condition, primary user is kept to be converted to sky by busy based on the flexible factor, primary user
Collision probability that is not busy and being changed into busy probability, acquisition secondary user's and primary user by the free time；
Collision probability according to secondary user's and primary user be no more than primary user patient maximum crash probability original
Then, the optimal flexible factor of each channel in N number of channel is calculated；
Step 103）Available channel using optimal channel of the flexibly factor more than or equal to 1 as secondary user's, and it is all
The number of available channel is G, and wherein G is less than or equal to N；
Step 104）Secondary user's are accessed into available channel, the SVC video datas of secondary user's are sent using G channel,
Return to step 101）, until all data of secondary user's are sent completely；
Wherein, the duration of the channel n progress SVC video data transmissions in G idle channel of secondary user's access isThe fixed slot length is " Ts+Tt”。
It is referred to for the logical relation of above-mentioned 4 steps shown in Fig. 2.
The principle of above steps and all formula being related to are as described below：
Multiple channels are there may be in cognitive radio networks, each channel has its corresponding primary user, primary user couple
The access of channel has priority, i.e., only when primary user need not transmit data, secondary user's could access channel and transmit
Data.And from the point of view of the side of secondary user's one, whether only can understand primary user by the detection to channel is transmitting data, enters
And it could judge whether channel is idle, can access and transmit data.Therefore secondary user's are just relied on the detecting strategy of channel
The mechanics of primary user, next, which also needs to design, can coordinate the secondary user's access scheme of multiple channels.The part will divide three
Individual subitem illustrates this thought.
1.1st, primary user's mechanics models --- continuous time Markov model
Such as a secondary user's monitor 8 channels, channel n（N=1,2 ..., 8）Corresponding primary user have two kinds from
Scattered state BUSY/IDLE, BUSY corresponds to primary user's busy condition（The busy BUSY of channel）, IDLE corresponds to primary user's idle condition
（Channel idle IDLE）.The mechanics of primary user obeys continuous time Markov model, i.e., between primary user's two states
Transfer obey Markov characteristic, while two states BUSY/IDLE duration obeys quantum condition entropy, but its is each
From parameter it is but not necessarily identical.Primary user Pn（N=1,2 ..., 8）Mean down time beThe average busy time isAssume in the embodimentIt is equal to 2 seconds, the probability density function of corresponding free time length is that parameter is αnRefer to
Number function, its expression formula such as formula（1）It is shown；The probability density function of busy duration is that parameter is βnExponential function, its table
Up to formula such as formula（2）It is shown,
According to the memoryless characteristic of exponential function, primary user PnFrom some moment（t=0）In at least ε times started
The probability for keeping its state ID LE or BUSY is respectively FI(ε) and FB(ε), it calculates such as formula（3）With（4）It is shown.According to FI
(ε) and FBIt is 1-F that (ε), which and then can also calculate primary user Pn states and be transformed to busy probability by the free time,I(ε) and by busy change
The probability for being changed to the free time is 1-FB(ε).According to above primary user's mechanics model, it is possible to predict primary user's a period of time
Activity situation, and then also can predicts channel n idle or busy situation.
2.1st, the access scheme of secondary user's
The secondary user's access scheme of prior art is the dynamic spectrum access scheme of fixed time slot, i.e., each channel when
Between be divided into continuous time slot on domain, the length of each time slot is fixed, and each time slot includes the detection period of fixed duration
TsWith the transmission period T of fixed durationt, T is set in the embodiments=10ms, Tt=50ms.Secondary user's are opened from the detection period
Beginning opening position sounding channel, if judging that channel is idle condition at the ending of detection period, secondary user's can connect
Enter channel and transmit data, otherwise secondary user's can not access channel.The detection period of multiple channels in cognitive radio networks
It is considered as with section boundary during transmission synchronous.Fig. 1 is illustrated to fix the dynamic spectrum access scheme of time slot with an example
Implication.
In order to further improve the utilization rate of channel width, according to the mechanics of primary user in the invention, spirit is devised
The dynamic spectrum access scheme of time slot living.Each channel is still divided into continuous time slot in time-domain in the program, but respectively
The length of time slot may be different：Detection duration is remained in that as Ts, but transmission duration can be according to the current moving type of primary user
Condition is adjusted, and the essence of this design is the reduction of unnecessary frequent channel detection.While in order to coordinate in each channel
Period and section boundary during transmission are detected, the length that a Flexible timeslot is provided in the design should be a fixed slot length
θ times (θ=1,2 ...), wherein θ is referred to as the flexible factor.
Fig. 4 illustrates the implication of the dynamic spectrum access scheme of Flexible timeslot with an example, empty wherein in channel 1,2,3
The flexible factor for the time slot that line rectangle is surrounded is respectively 2,2,3.Although it can be seen that in Flexible timeslot structure simultaneously from example
Section boundary all Complete Synchronizations when detection period in not all channel and transmission, but the period is detected with transmitting the side of period
Boundary or Partial synchronization, this effective distribution for being data in multichannel provides condition.
3.1st, the decision-making of optimal flexibly factor θ
Channel n（N=1,2 ..., 8）The detection period from SBMoment, to SEMoment terminates.Secondary user's are right every time
After channel n detection is completed, i.e. SEAt the moment, it can all obtain a result of detection RS, the fruit that RS=0 represents detection is IDLE, is believed
Road is idle；The result that RS=1 represents detection is busy as BUSY, channel.But unstable, the other users signal of signal intensity are done
The inaccuracy of result of detection can be caused by the factor such as disturbing, therefore be IDLE state, i.e. AS=0 when channel is actual, but result of detection is
BUSY, i.e. RS=1, we term it the probability γ that false-alarm, false-alarm occurn；It is BUSY states, i.e. AS=1 when channel is actual, but visits
Survey result is IDLE, i.e. RS=0, and we term it false dismissal, the probability that false dismissal occurs is δn。
Considering the possibility of false-alarm and false dismissal, and in the case of channel history information, channel n is in SEMoment is actual empty
Not busy probability is set to, it calculates such as formula（5）It is shown,（5）Calculating reference formula（6）With（7）,
In above formulaThe state for representing channel n respectively keeps IDLE within the detection period
Probability, the probability that transforms to from BUSY IDLE probability, BUSY is transformed to from IDLE and the probability for keeping BUSY.It is each to visit
Survey period TsInterior or transmission period TtThe conversion of interior channel status at most occurs once, because TsAnd TtIt is remote in practice
Less than the duration of a certain state of primary user, therefore according to formula（3）With（4）, can obtain
What is be respectively worth is calculated as follows,
Formula（6）With（7）InIt is channel n in SBMoment actual idle probability, the probable value rely on SBWhen
The state of a upper non-slotted channel n before quarter.When in SBSecondary user's success before transmits data in channel n, then it is assumed that
Probability idle channel n is；When in SBSecondary user's think channel n skies before after being collided with primary user
Not busy probability is；When secondary user's do not transmit data in the channel, then the period can be detected according to a upper time slot
Channel idle probability afterwards calculates, it calculates such as formula（12）It is shown,
In above formulaRepresent channel n and detect finish time period in a upper time slotWhen idle probability；
WithChannel n state is represented respectively in transmission duration TtInterior holding IDLE probability and transform to the general of IDLE from BUSY
Rate, therefore according to formula（3）With（4）, can obtainTwo values are calculated as follows,
Derivation more than, can obtain SEProbability idle moment channel n.Herein on basis, when this is set
The flexible factor of gap is θ, i.e., the Flexible timeslot is θ times of fixed slot length, then from SEMoment starts to the Flexible timeslot
The time at end is θ (Ts+Tt)-Ts.If within this time, channel status is converted to BUSY by IDLE, then there occurs master
User and the collision of secondary user's, the probability stamps of collision are, according to formula（3）With（4）It can calculateIt is as follows,
Primary user corresponding to known channel n patient maximum collision probability beIt should then cause in decision-making θIt is no more thanSo optimal flexible factor that channel n adopts at the decision-making momentCalculating such as formula（16）Institute
Show, whereinIt is to round symbol downwards.
To channel n, if calculatedThen mean channel n probably in ensuing transmission period TtIn
Busy condition is transformed to by idle condition, then secondary user's should not access channel；IfThen mean channel n shape
State is in ensuing transmission period TtInterior smaller by the idle probability for being transformed to busy condition, secondary user's can access channel simultaneously
Transmit data, especially whenWhen, the advantage of the dynamic spectrum access scheme of Flexible timeslot emerges from, channel width
Utilization rate is lifted.
Two, additionally provided when the present invention is for sending SVC data based on SVC videos with cognitive radio is multi channel grades
Level matching strategy, i.e., further optimize above-mentioned steps 104）The method for sending the SVC video datas of secondary user's, this method tool
Body includes：
Step 104-1）SVC video datas are set into priority and the starting point and cut off of each frame are set, positioned at starting
NALU in the range of point and cut off is effective, and effective NALU is placed on according to priority and sent in buffering area；
Step 104-2）Will send buffer area in each NALU split encapsulation, and will split encapsulation packet transmission with
G idle interchannel carries out dynamic adaptation, so as to which the packet of more high priority is used into the more reliable channel of channel performance
It is transmitted.
It is referred to for the logical relation of above-mentioned two step shown in Fig. 3, and above-mentioned steps 104-1）And 104-2）
Concrete principle and implementation be described in detail as follows：
2nd, SVC videos and the multi channel graduation matching strategies of CR
The relevant portion of the present invention gives multi channel model in CR networks, and this model is also the part on SVC
The basis that video matches with the graduation of CR multichannels.The strategy that SVC videos match with the graduation of CR multichannels has specifically included three
Individual subitem：The distribution of SVC video data priorities, consider that the priority orders data of data age send arrangement scheme, number
According to the matching algorithm with channel, these three subitems interknit and constitute the graduation matching strategy of the part.
2.1st, the distribution of SVC video data priorities
Prior art has scalability using the SVC of layered encoding structure in three dimensions：Quality dimensions, time dimension
Degree and Spatial Dimension.SVC can go out regarding containing multiple quality layers, multiple time horizons and multiple space layers according to configuration codes
Frequently, each specific layer corresponds to specific video definition, frame per second and spatial resolution.In practical application, user can root
Some specific quality layers, time horizon and space layers in extraction SVC videos are needed according to oneself, it is a certain specific clear so as to obtain
The compression video of degree, frame per second and spatial resolution.
SVC uses GOP in the present invention（Group of Pictures）Structured coding video, quality scalable dimension adopts
Use MGS（Medium Grain Scalability）Coding structure, time scalable dimension using Hierarchical-B compile
Code structure, spatial scalability are not used.There are 4 mass segregations in the SVC video datas being encoded into the embodiment（F0,
F1, F2, F3）It is layered with 4 times（T0, T1, T2, T3）, then each GOP will have 2^ (4-1)=8 frame, 8 are referred to as GOP rule
Mould, the data of each frame are encoded into 4 NALU by mass segregation again（Network Abstraction Layer Unit）In, institute
To share 8*4=32 NALU in each GOP, Fig. 5 is that the data of the embodiment are formed.
In time scalable dimension, the time layering that the video data obtained by user includes is more, then means to regard
The frame that frequency includes is more intensive, and the video that video is decoded and obtained when playing will be more smooth.But the prediction used in SVC codings
Coding and layered encoding structure cause the frame that time stratum level is higher in video directly or indirectly to rely on some time layerings etc.
The relatively low frame of level.I.e. if some time that a higher frame of time stratum level directly relies on or indirectly relying on layering etc.
The relatively low frame of level is not present, then this frame cannot be decoded smoothly.Therefore setting time stratum level is lower in the invention
Frame priority it is higher.There can be multiple time stratum level identical frames in one GOP simultaneously, when being set in the invention
Between in stratum level identical frame the more early frame priority of those playing sequences it is higher.
In quality scalable dimension, the effective mass segregation data included in a frame are more, then mean to solve
The NALU of code is more, and the image that the frame is decoded rear gained is more clear.According to SVC coding principles, some matter is in a frame
The decoding dependency for measuring the NALU of stratum level is less than those NALU of the NALU in all mass segregation grades.Only when being relied on
Those NALU when all exist, a NALU just can be decoded smoothly, and be considered as effective.Therefore in the invention
It is higher to set the NALU priority of mass segregation lower grade in a frame.
In the case of resource-constrained, user is more likely on the basis of video fluency is ensured, just goes further to obtain
More quality enhancement layer datas are obtained to go to increase the definition of video.Therefore considering quality scalable dimension and time can stretch
Contracting dimension, the invention set the priority of the NALU in identical mass segregation grade in those different frames, are integrally higher than
Those mass segregation higher grades NALU priority, overall NALU's less than those mass segregation lower grades is preferential
Level.
In summary analyze, 32 included in the GOP in the embodiment NALU will be allocated unique corresponding preferential
Level, the index of priority is 1,2 ..., 32, wherein it is higher to index the smaller priority for meaning NALU.Fig. 5 is that the embodiment regards
Frequency data priority distribution diagram.
2nd, consider that the priority orders data of data age send arrangement scheme
The order that frame of video is encoded is different from the playing sequence of frame of video, in Fig. 6（a）It is video in the embodiment
The coded sequence of frame；The order that frame of video is sent in the invention simultaneously had both been different from the playing sequence of frame, was different from frame again
The order being encoded.The other transmission order of frame level set in the invention is consistent with the other priority of frame level, i.e., frame is excellent
First level is higher, and the more early consideration of the frame is sent, in Fig. 6（b）It is the transmission order of frame of video in the embodiment.One frame is by more
Individual NALU compositions, the invention devises a kind of consideration NALU timeliness based on the other transmission order of frame level, in NALU ranks
Property priority orders data send arrangement scheme.
A starting point and a cut off are allocated according to the other transmission order of frame level, each frame in one GOP, only
When being between the starting point of the frame and cut off the current time, it is multiple effectively, in the frame just to think the frame
NALU is effective, and these NALU, which should be placed into, to be sent in buffering area with to be sent.When cut off reaches, in buffering area
Failure is all dropped by the data not yet sent, and starts effective NALU in next GOP being placed into buffering area.Starting
Point and cut off set rule as：Time difference between adjacent two frames starting point is equal to time interval during two frame normal plays；
All frames share same cut off in one GOP, and this cut off is also the starting point of next frames of GOP first.Therefore
At a time, send in buffering area may have the NALU for being still within the term of validity in multiple frames wait it is to be sent, these
NALU is arranged in buffering area is sent according to priority, and the more early considerations of the higher NALU of priority are sent, and this is to consider
The priority orders data of data age send the implication of arrangement scheme.
Fig. 7 is that the figure is with Fig. 6 using the embodiment as background explanation such scheme（b）The middle other transmission order of frame level is base
Plinth,（1、9、17、25）The NALU in frame 1 is represented,（2,10,18,26）The NALU in frame 2 is represented, the like；Starting point and cut
The implication of stop can also be found out by Fig. 7 examples.At the time point of red arrow logo, frame 1, frame 2 and frame 3 are all in the term of validity
In, their NALU, which should be placed to, to be sent in buffering area and is transmitted according to NALU priority orders, the number in figure
It has been successfully sent, and has indexed as 3,11,17,18,19,25,26 and 27 for 1,9,2 and 10 NALU according to meaning to index
It is medium to be sent that NALU still stays in transmission buffering area successively.
Consider that the advantage of the priority orders data transmission arrangement scheme of data age is embodied in two aspects.1）In CR
In network multiple-channel environment, secondary user's may have multiple idle channels can use simultaneously at some decision-making moment, and it is multiple can
Channel may have larger gap in terms of the reliability of transmission data.Using the priority of consideration data age as above
Alphabetic data sends arrangement scheme, and the medium NALU to be sent of transmission buffering area priority limit can be made larger, i.e., higher
The NALU of priority, high medium priority and lower priority is present.Under such arrangement scheme, it can be incited somebody to action with next subitem
The data and the matching algorithm of channel to be made referrals to so that the higher NALU of importance is often using can in long term time frames
It is transmitted by the higher channel resource of property；Often the relatively low channel resource of application reliability is passed the relatively low NALU of importance
It is defeated.2）The delivery plan is based on the other priority orders of frame level, therefore the higher frame of importance tends to earlier
Arrange its NALU transmission using channel resource, and the NALU in the relatively low frame of importance be then possible to when cut off closes on because
CR channel resource deficiencies have little time to send, so as to be simply discarded.In the case of resource-constrained, the program causes limited letter
Road resource is used for the transmission of the relatively heavy video data wanted, while again leads to data more important in the data that these are transmitted
Cross more reliable channel resource to be transmitted, the relatively poor data of importance are entered by the relatively poor channel resource of reliability
Row transmission.Which ultimately increases the validity of the video data received, the video data that can not be decoded received is reduced, depending on
The quality of frequency is improved.
3rd, SVC data and the multi channel matching algorithms of CR
A secondary user's with multiple wave points detect 8 channels simultaneously in above-described embodiment, at certain once
The collection that available channel is formed during decision-making is combined into C={ c1,c2,...,cg,...,cG, it is 8 channels that wherein G, which is no more than 8, C,
A subset；The set expression that NALU in buffering area is sent at the decision-making moment is Φ={ φ1,φ2,...,φk,...,φK,
Wherein K is no more than 32, and φk＜ φk+1, index as φkNALU priority can be more than index be φk+1NALU it is excellent
First level.
SVC video datas are transmitted with data packet form.Index as φkNALU length beTo it
Carry out splitting the bag number that can split into of package beWherein LspuTo tear the length of packetized units open, the implementation
L in examplespu1400 are set to, so each that to be dispatched bag has an indexIt is by indexThe operation that is arranged in when in CR channels of bag beIt will index and beBag be arranged in work as
Channel c after the preceding decision-making momentgIn q-th of package location on.Index as φkNALU in all bags transmission arrangement
Set expression beAnd then in the range of channel width limitation, the final individual NALU of K ' for arranging to complete transmission arrangement set
Constitute a vectorSVC data and the multi channel matching algorithms of CR in the invention are exactly optimal in order to find one
Vector
Packet may be because radio link quality difference during transmission or be collided and be lost with primary user
Lose；And the NALU decodable codes are just only thought after all subpackages all have received in a NALU, index as φkNALU
The probability that is successfully received and can decode can be expressed asSVC data in the invention and CR multichannel matching schemes be by
It is approved for distribution to send the descending of NALU priority in buffering area to maximize the probability that they are successfully received and decoded successively, obtained with thisAnd reach effect of optimization, such as formula（16）With（17）It is shown.
Represent if using feasible solutionWhen be assigned to channel cgIn data volume；Represent channel cgInstitute
The stock number that can be provided, can pass through formula（18）Obtain, whereinRepresent channel cgBandwidth, each channel in the embodiment
Bandwidth range be all 400Kbps-1Mbps,It is channel cgThe optimal flexible factor.
Formula（17）InBag is represented respectivelyArrangingIn the case of link lose
Bag probability and collision drop probabilities.Any bit in one packet all thinks the bag because channel link qualities make a mistake
There occurs packet loss of link, the bit error rate of a channel and the SNR of the channel（Signal-to-noise ratio, signal to noise ratio）
It is closely related with modulating mode, channel cgBit error rate be identified asIt calculates such as formula（19）It is shown, wherein R tables
Show the channel SNR, amAnd bmIt is empirical coefficient when using index as m modulating mode, they can pass through 1 acquisition of tabling look-up.Enter
And can be according to channel cgBit error rate derive bagPacket loss of link probabilitySuch as formula（20）It is shown.At this
The modulating mode that embodiment uses is that for code efficiency corresponding to index m=2 for 1/2 QPSK, SNR scope is 6-50dB.
Parameter list under the different modulating pattern of form 1
| AMC（m） | m=1 | m=2 | m=3 | m=4 | m=5 | m=6 |
| Modulation | BPSK | QPSK | QPSK | 16-QAM | 16-QAM | 64-QAM |
| Coding Rate | 1/2 | 1/2 | 3/4 | 9/16 | 3/4 | 3/4 |
| am | 1.1369 | 0.3351 | 0.2197 | 0.2081 | 0.1936 | 0.1887 |
| bm | 7.5556 | 3.2543 | 1.5244 | 0.6250 | 0.3484 | 0.0871 |
To bagCollision drop probabilitiesCalculating be actually estimate it is main before the coating is properly received
User resumes channel cgProbability, i.e., touched if resuming channel in some moment primary user with secondary user's
Hit, then schedule ahead in the channel, the bag that is not yet successfully received will all lose.Channel cgBand it is a width ofBagIt is arranged at channel cgIn q-th of package location, it transmit need time beAnd then it can push away
Transmitted data to calculating after the decision-making including bagThe time that inside q bag be expected to be successfully received needs isIf in this tqChannel status is converted to busy by the free time in time, i.e., primary user has resumed channel, that
BagJust there occurs collision packet loss, its probability calculation formula is such as（21）It is shown.
The above is SVC data and the multi channel matching ideas of CR, and the present invention also follows the thought and devises a greed calculation
Method obtains best fit strategyI.e. the present invention realizes SVC data and the multi channel matchings of CR using greedy algorithm.The reality
Apply when performing the algorithm in example current priority highest bag always to arrange prior to others coating, and be to be arranged using can carry
It is transmitted for the channel resource of highest Successful transmissions probability.Pass through the solution obtained by the greedy algorithmWith it is above
SVC data are consistent with the expection solution in the multi channel matching ideas of CR；And avoided using the greedy algorithm to numerous
Feasible solution traversal, greatly reduce amount of calculation.
The invention described above use greedy algorithm be specially：
When set of available channels is C={ c1,c2,...,cg,...,cG, send buffering area in NALU set Φ=
{φ1,φ2,...,φk,...,φKWhen：
Step 301）By optimal vectorIt is initialized as：Wherein,Represent empty set；
Step 302）Each NALU sent in buffering area in effective NALU set Φ is split into simultaneously package；
Step 303）Judge send in buffering area whether have the bag not sent, if entering step 304）；Otherwise enter
Enter step 306）；
Step 304）Judge whether there is available channel resource in set C, if then entering step 305）；Otherwise enter
Step 306）；
Step 305）Send to take out in buffering area from data and come most preceding bag（Highest priority), it is assumed that for bagSuccessful transmissions probability when calculating it respectively remaining available channel being transmitted in set C；
Selection can provide the transmission arrangement of the channel and specific package location of maximum Successful transmissions probability as the bag, such as position
Put (cg,q)；
It will arrangeIt is added to setIn,In an element；
Update in set C in remaining available channel information and channel specifically remaining available volume of resources information；Renewal is sent
Remaining packet information to be sent in buffering area Φ；Return to step 303）；
Step 306）Obtain SVC data and the best fit strategy of Wireless Multi-Channel
In summary, the present invention relates to a kind of SVC（Scalable Video Coding）Video is believed the cognitive radio more
Transmission dispatching method in road environment, its using cognitive radio technology can improve wireless signal-path band width utilization rate the characteristics of,
More radio channel resources can be excavated out, and then promote the development of the Video Applications of high bandwidth；SVC video scalabilities are utilized again
The characteristic adaptability good to time varying channel, the validity of transmission of video is improved, can properly increase and connect under the conditions of equivalent channel
The quality of rating frequency.The invention is further optimized based on the inherent advantage of cognitive radio and SVC videos：It is proposed
One dynamic spectrum access scheme based on Flexible timeslot, the program consider the mechanics of primary user, and it is unnecessary to reduce
Channel detection, further increase the utilization rate of wireless signal-path band width；A SVC video is devised with cognitive radio to believe more
The graduation matching strategy in road, the strategy pass through the priority of reasonable distribution SVC video datas, the hair of arrangement SVC video datas
Order and SVC video datas and the multi channel dynamic adaptation of cognitive radio are sent, is enabled in a long term time frames
The higher SVC data of importance are transmitted by the higher radio channel resource of reliability, the relatively low SVC video counts of importance
It is transmitted according to by the relatively low channel resource of reliability, improves video transmission efficiency.Optimized by both sides, can had more
More video data Successful transmissions, and the validity of the video data received is higher, the video that this final optimization pass receives
Quality.
The dynamic spectrum access scheme based on Flexible timeslot in the present invention reduces the detection period within certain limits
Number, be advantageous to improve the utilization rate of channel resource.SVC videos cause long-term interior with the multi channel graduation matching strategies of CR
The higher data of importance can be transmitted by the higher channel of reliability, and the relatively low data of importance can be by reliable
The relatively low channel of property is transmitted.The video quality that this 2 advantages of the invention can to receive further is carried
Rise.
It should be noted last that the above embodiments are merely illustrative of the technical solutions of the present invention and it is unrestricted.Although ginseng
The present invention is described in detail according to embodiment, it will be understood by those within the art that, to the technical side of the present invention
Case is modified or equivalent substitution, and without departure from the spirit and scope of technical solution of the present invention, it all should cover in the present invention
Right among.
Claims (9)
1. a kind of transmission dispatching method of SVC videos in cognitive radio multichannel, methods described include：It is first some time
The channel of level user's detection defines the flexible factor, and the flexible factor is used for the slot length for describing channel；Then, based on it is flexible because
The optimal flexible factor for each channel that son and primary user's mechanics are detected；Finally, judge to use according to the optimal flexibly factor
The channel and user that family has access to access the length of the transmission period of some channel；
The transmission dispatching method specifically includes：
Step 101) secondary user's are in TsThe free time of the N number of wireless channel of detection or busy condition, then define N number of letter in period
The slot length of each channel in road is θ times of a fixed slot length, and the θ is the flexible factor；
Step 102) establishes the mechanics model of primary user, and obtain primary user according to model keeps idle within certain section of period
The probability of state or busy condition, and obtain primary user and be converted to the free time by busy within this time or be converted to by the free time busy
Commonplace probability；
Based on the flexible factor, primary user keep the probability of idle condition or busy condition, primary user by it is busy be converted to it is idle and
Busy probability is changed into by the free time, obtains secondary user's and the collision probability of primary user；
Collision probability according to secondary user's and primary user is no more than the principle of the patient maximum crash probability of primary user institute, counts
Calculate the optimal flexible factor of each channel in N number of channel
Step 103) regard optimal channel of the flexibly factor more than or equal to 1 as the available channel of secondary user's, and all can use
The number of channel is G, and wherein G is less than or equal to N；
Secondary user's are accessed available channel by step 104), and the SVC video datas of secondary user's are sent using G channel, are returned
Step 101), until all data of secondary user's are sent completely；
Wherein, the duration of n-th of channel progress SVC video data transmissions in G idle channel of secondary user's access isThe fixed slot length is " Ts+Tt", TtFor the period of a fixed size.
2. transmission dispatching method of the SVC videos according to claim 1 in cognitive radio multichannel, its feature exist
In the calculation formula of any one channel n optimal flexibly factor is as follows：
Wherein,The probability to be collided for secondary user's and primary user in channel n,For primary user institute energy on channel n
The maximum collision probability of tolerance, the channel n are some channel in N number of channel.
3. transmission dispatching method of the SVC videos according to claim 2 in cognitive radio multichannel, its feature exist
In describedCalculation formula be：
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The ending moment, αnValue according in channel n primary user activity historical data obtain, the value be equal to channel n in primary user
The inverse of the desired value of duration in idle period.
4. transmission dispatching method of the SVC videos according to claim 3 in cognitive radio multichannel, its feature exist
In acquisitionThe step of be：
Step 201) obtains the step of primary user's mechanics model, is specially：
The mechanics of primary user obeys continuous time Markov model, i.e., turns between the free time of primary user and busy condition
Move and obey Markov characteristic, while the duration of " busy and idle " two states of primary user obeys following negative finger respectively
Number distribution, obtains following quantum condition entropy and obtains primary user's mechanics model：
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fB(t) represent the busy probability density function of primary user in channel n in the value of t, βnValue according to channel n
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Step 202) is predicted within (0, the ε) period, master according to the mechanics model of obtained primary user according to equation below
The idle or busy probability of channel n shared by user：
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Wherein, FI(ε) and FB(ε) is respectively primary user from the t=0 moment to keeping idle condition in the period at t=ε moment
With the probability of busy condition；“1-FI(ε) " is primary user from the t=0 moment to being transformed to by the free time in the period at t=ε moment
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Step 203) defines detection finish time Ss of the channel n in secondary user'sEWhen actual idle probability be：
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Wherein, detection period of the secondary user's to channel n is from SBMoment, to SEMoment terminates；RS is secondary user's each
Moment, i.e. S are completed in detection to channel nEThe result that moment, an obtained result of detection, and RS=0 represent detection is idle
State, RS=1 represent the result of detection as busy condition；γnThe probability occurred for false-alarm, i.e., be idle shape when channel is actual
State, i.e. AS=0, but result of detection is busy, i.e. RS=1；δnThe probability occurred for false dismissal, i.e., be busy shape when channel is actual
State, i.e. AS=1, but result of detection is idle condition, i.e. RS=0；
Step 204) is according to FI(ε)、FB(ε)、1-FI(ε) and 1-FB(ε) obtains P (AS=0) and P (AS=1) value, is specially：
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Wherein,WithRepresent respectively probability that channel n state keeps idle within the detection period,
Busy probability is transformed to from the busy probability for transforming to the free time, from the free time and keeps busy probability；For channel n
In SBMoment actual idle probability, the probable value rely on SBThe state of a upper non-slotted channel n before moment；When in SBIt
The success of preceding secondary user's transmits data in channel n, then it is assumed that probability idle channel n isWhen in SBIt is previous
Level user thinks that the idle probability of channel n is after being collided with primary userWhen secondary user's not in the channel
Data are transmitted, then the channel idle probability reckoning after the period can be detected according to a upper time slotAnd's
Prediction equation is as follows：
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Represented a upper detection time slot finish times of the channel n in secondary user'sWhen idle probability；WithChannel n state is represented respectively in transmission duration TtIt is interior to keep the probability of free time and transform to idle probability from busy
Value.
5. transmission dispatching method of the SVC videos according to claim 1 in cognitive radio multichannel, its feature exist
Further included in the step of, SVC video datas of the transmission secondary user's described in step 104)：
Step 104-1) SVC video datas are set into priority and the starting point and cut off of each frame be set, positioned at starting point and
NALU in the range of cut off is effective, and effective NALU is placed on according to priority and sent in buffering area；
Step 104-2) each NALU that will send in buffer area splits encapsulation, and will split the transmission of the packet of encapsulation with it is idle
G interchannel carry out dynamic adaptation, so as to which the packet of more high priority be carried out using the more reliable channel of channel performance
Send.
6. transmission dispatching method of the SVC videos according to claim 5 in cognitive radio multichannel, its feature exist
In the step 104-1) further include：
Step 104-1-1) obtained SVC video datas will be encoded using GOP and carry out priority division according to following principle：
It is higher to set the priority of the frame that time stratum level is lower in a GOP, and multiple time stratum level identical frames
The more early frame priority of middle playing sequence is higher；
And meet：
Mass segregation lower grade NALU priority is higher in a frame in one GOP；
And meet：
The priority of all NALU in one GOP in a certain mass segregation grade, it is overall to be higher than positioned at higher quality point
The priority of all NALU in layer grade, and less than the priority positioned at all NALU more on low quality stratum level；
Step 104-1-2) transmission order according to all frames in one GOP of priority level initializing of definition, and to be each in the GOP
Frame distributes a starting point and a cut off, when being sometime between the starting point of some frame and cut off, then should
All NALU in frame are effective, and these effective NALU are sorted according to the priority of definition in buffering area is sent；
Wherein,
When cut off reaches, the NALU data sent in buffering area but not yet will fail and be dropped, and start by
Effective NALU in next GOP is put into buffering area；
The setting principle of above-mentioned starting point and cut off is：When time difference between adjacent two frames starting point is equal to two frame normal plays
Time interval；And all frames share same cut off in a GOP, the shared cut off is in next GOP
Comprising the first frame starting point.
7. transmission dispatching method of the SVC videos according to claim 5 in cognitive radio multichannel, its feature exist
In the step 104-2) further include：
Step 104-2-1) collection that forms of the available channel that detects to obtain by the secondary user's when in certain decision-making is combined into C
={ c1,c2,...,cg,...,cG, and NALU set expression is Φ={ φ in buffering area is sent at the decision-making moment1,
φ2,...,φk,...,φK}；
Wherein, φk＜ φk+1, i.e., index is φkNALU priority be more than index be φk+1NALU priority；
Step 104-2-2) descending of NALU priority in buffering area is sent according to above-mentioned detection moment, NALU is maximized successively
Each element φ in setkThe probability for successfully being received and being decoded, finally give the optimal transmission peace for sending video source data
Row's vector；
Wherein, will be carried out positioned at the channel sent in NALU and the available channel set C in buffering area according to optimal vector
Match somebody with somebody.
8. transmission dispatching method of the SVC videos according to claim 7 in cognitive radio multichannel, its feature exist
In the step 104-2-2) using equation below determine it is optimal send arrange vector：
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Wherein,
Index as φkNALU length beIt is carried out to split the bag number that can split into of package beIts
Middle LspuTo tear the length of packetized units open, so each that to be dispatched bag has an index
It is by indexThe operation that is arranged in when in CR channels of bag beIt will index and beBao An
Come the channel c after the current decision momentgIn q-th of package location on；Index as φkNALU in all bags hair
The set expression for sending arrangement is
It is above-mentionedRepresent that index is φkNALU be successfully received and the probability that can decode,Represent bagAccording toPacket loss of link probability in the case of arrangement,Represent bagAccording toThe situation of arrangement
Under collision drop probabilities,Represent that by index be φkNALU carry out splitting the index of each bag that encapsulation obtains, k's
Span is 1≤k≤K '.
9. transmission dispatching method of the SVC videos according to claim 8 in cognitive radio multichannel, its feature exist
In using greedy algorithm acquisition optimal vectorValue, be specially：
When set of available channels is C={ c1,c2,...,cg,...,cG, send buffering area in NALU set Φ={ φ1,
φ2,...,φk,...,φKWhen：
Step 301) is by optimal vectorIt is initialized as：Wherein,Represent empty set；
Each NALU sent in buffering area in effective NALU set Φ is split simultaneously package by step 302)；
Step 303) judges send in buffering area whether have the bag not sent, if entering step 304)；Otherwise step is entered
It is rapid 306)；
Step 304) judges whether there is available channel resource in set C, if then entering step 305)；Otherwise step is entered
306)；
Step 305) sends to take out in buffering area from data comes most preceding bag, it is assumed that for bagIt is calculated respectively to gather
Successful transmissions probability when remaining available channel is transmitted in C；
Selection can provide the transmission arrangement of the channel and specific package location of maximum Successful transmissions probability as the bag, such as position
(cg,q)；
It will arrangeIt is added to setIn,It isIn an element；
Update in set C in remaining available channel information and channel specifically remaining available volume of resources information；Renewal sends buffering
Remaining packet information to be sent in area Φ；Return to step 303)；
Step 306) obtains SVC data and the best fit strategy of Wireless Multi-Channel
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| CN102088324A (en) * | 2011-03-24 | 2011-06-08 | 电子科技大学 | Spectrum detection method of cognitive radio system |
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| CN103313054A (en) * | 2013-05-22 | 2013-09-18 | 中国科学院声学研究所 | Transferring and scheduling method of scalable video coding (SVC) video |
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