CN104333779B - The bandwidth allocation methods of Stream Media Application fast cache - Google Patents

Abstract

The bandwidth allocation methods of Stream Media Application fast cache of the present invention, for the scene of single base station multi-user in mobile cellular net, under the scene, channel competition can occur between multiple users, cause data awaiting transmission and video cardton, the present invention disposes bandwidth allocation agency between the base station of Cellular Networks and core net, bandwidth allocation acts on behalf of the service bandwidth of periodic collection network flow-medium application, the signal strength information of each user, the information such as the speed that each user video is played, the stream medium data size of user's request；When mobile subscriber's request stream medium data in network, the bandwidth allocation algorithm of agency's operation Stream Media Application fast cache, the distribution of Streaming Media bandwidth is carried out for the Streaming Media user in Cellular Networks, can ensure that each user can glibly play video, buffer time and the interim card of video are reduced, Consumer's Experience is improved.

Description

The bandwidth allocation methods of Stream Media Application fast cache

Technical field

The invention belongs to the Stream Media Application bandwidth resource allocation technical field in mobile cellular net, more particularly to a kind of stream The bandwidth allocation methods of media application fast cache.

Background technology

The Stream Media Applications such as current PPLive, youku.com are increasingly welcome by masses, with the wireless access skill such as 3G and LTE Art is developed rapidly, and user increasingly liked in the online video of bus, subway.Referred to according to the cisco networks of 2014 Number investigation report, the flow of current Stream Media Application has accounted for the 53% of total network traffics, it is contemplated that by 2018, be up to 69% or so.Therefore, it is very necessary and urgent to improve Consumer's Experience of the user when streaming media video is watched.

In mobile cellular net, the index for weighing mobile flow medium application is mainly buffer time.When mobile client is slow When depositing middle data less than a thresholding, video playback pause, it is necessary to wait pending data to be played again after downloading, during the interval of this section of video Between be buffer time.Video playback is more smooth, and buffer time is smaller, and Consumer's Experience is better.But in wireless mobile cellular net In, due to the bandwidth for changing, the competition between the continuous mobility of user and multi-user all may result in stream medium data Insufficient supply, cause user watch video interim card.

For the interim card problem of video, existing work is concentrated mainly on and meets the current code check of user and control wait team Arrange the two aspects.Ali et al. reduces interim card number of times by the control of the buffer size to unique user.This article root Reached according to Markov Chain streaming media data and using being analyzed, so as to reduce the number of times of interim card.But, article is not examined Consider the change of network signal intensity and the situation of multiple users, be only suitable for theoretic research and analysis, in practical application In reference value than relatively limited.

Article PROTEUS considers the change of network condition, by the signal intensity and network of predicting following a period of time Situation adjusts the download of video data, improves the experience of user.Because the accuracy predicted network condition will have a strong impact on The performance of system, therefore reliable accuracy can be reached seem particularly significant.According to investigation, the prediction of machine learning, it is accurate The method that true rate only has 70% or so, historical path prediction can reach 90% or so in the ideal case.Therefore, using prediction To improve the experience of user, there is certain risk.Chen et al. has put forward a kind of dispatching algorithm, meets the current bit of user Rate, improves resource utilization.But the method ensures the broadcasting of current video, the broadcasting situation not looked to the future, and delays Middle data are deposited also not embody the influence played.

The content of the invention

In order to overcome the shortcoming of above-mentioned prior art, it is an object of the invention to provide a kind of Stream Media Application fast cache Bandwidth allocation methods, when in a mobile cellular net base station range, having multiple user's request stream medium datas, between multi-user There is the competition of channel, the wait of data transfer and the interim card of video, the present invention can be caused to be directed to this scene, by online tune Degree, it is not necessary to be predicted to signal intensity, improves the practicality and bandwidth availability ratio of algorithm, ensure that streaming media video is broadcast The fluency put, improves the experience that user plays, and is applicable not only to the scene of single base station, can be applicable to single AP resource contentions Scene.

To achieve these goals, the technical solution adopted by the present invention is：

A kind of bandwidth allocation methods of Stream Media Application fast cache, portion is needed between the base station of Cellular Networks and core net Administration bandwidth allocation agency, when mobile subscriber's request stream medium data in network, bandwidth allocation agency is as follows each Individual user's distribution bandwidth：

Step one, in time slot t, user i is M to bandwidth allocation proxy requests stream medium data, size_i, bandwidth allocation Proxy records user；If time slot t have user leave or user data end of transmission, bandwidth allocation agency discharges the use The request at family, no longer for it distributes wide bandwidth resource；

Step 2, bandwidth allocation agency collects the signal intensity s of user i_i(t), the Mean Speed p that user video is played_i, Base station records this time slot with parameter S and distributes remaining amount of bandwidth in available streaming media service bandwidth B (t) of this time slot, when When gap starts, S=B (t) is made；

Step 3, bandwidth allocation agency is allocated according to the data collected to user's request bandwidth now：Initially Change, d_iT bandwidth that () record bandwidth assignment agent is distributed in time slot t to user i, when time slot starts, assigns initial value 0, d_i(t)← 0, i=1,2 ..., N；d_supI () records bandwidth assignment agent can be to the maximum bandwidth of user i distribution, in time slot in this time slot During beginning, initial value 1, d is assigned_supI () ← 1, i=1, wherein 2 ..., N, N are user's number；Note bandwidth allocation intermediate parameters are designated as d′_iT (), when time slot starts, makes d '_i(t)=d_i(t)；Note bandwidth left amount intermediate parameters are designated as S ', when time slot starts, order S '=S；

Step 4, by the playback rate p of N number of user_iIt is ranked up from small to large, and renumbers, calculates each user The data volume d for maintaining smooth playing to be needed to next time slot_need(i)；

Step 5, from the 1st user to n-th user, when base station is in the remaining bandwidth S of this time slot>When 0, first is carried out Secondary bandwidth allocation：

A () calculates now this base station can be to the data volume d of user i transmission_sup(i)；

If (b) d_sup(i)3d_needI (), then make d_i(t)=d '_i(t)+d_need(i), S=S '-d_need(i), d_sum=B T ()-S, now updates bandwidth allocation intermediate parameters d '_iT () and remaining bandwidth intermediate parameters S ', makes d '_i(t)=d_i(t), S '= S；

If (c) d_sup(i)<d_need(i), then d_i(t)=d '_i(t)+d_sup(i), S=S '-d_sup(i), d_sum=B (t)-S, And update bandwidth allocation intermediate parameters d '_iT () and remaining bandwidth intermediate parameters S ', makes d '_i(t)=d_i(t), S '=S；

Wherein d_sumExpression has distributed data volume, is recording parameters；

Step 6, the now system that calculates can be to the data volume d of user i transmission_sup(i)；

Step 7, if now remaining bandwidth S>When 0 and there is d_sup(i) ≠ 0, then by remaining bandwidth allocation to user, From the 1st user to n-th user, the data to user's one time slot of distribution are p every time_i, it is ensured that the fairness of user：

If (a) d_sup(i)≥p_i, then d_i(t)=d '_i(t)+p_i, S=S '-p_i, d_sum=B (t)-S, and update bandwidth point With intermediate parameters d '_iT () and remaining bandwidth intermediate parameters S ', makes d '_i(t)=d_i(t), S '=S；

If (b) d_sup(i)<p_i, then d_i(t)=d '_i(t)+d_sup(i), S=S '-d_sup(i), d_sum=B (t)-S, and more New bandwidth allocation intermediate parameters d '_iT () and remaining bandwidth intermediate parameters S ', makes d '_i(t)=d_i(t), S '=S；

Step 8, the now system that recalculates can be to the data volume d of user i transmission_sup(i), if remaining bandwidth S> When 0 and there is d_supI () ≠ 0, rerun step 7；

Step 9, according to the d of distribution_iT () carries out bandwidth allocation to user present in base station；

Step 10, scheduling enters next time slot, perceives the entrance of user and leaving for user, change of service bandwidth etc., Carry out new round scheduling decision.

Here is the basic mode for arriving used herein and parameter setting：

Define 1

Data block：The stream medium data that one mobile terminal is received in a time slot, referred to as one data block.Data block must Must receive use completely, i.e., data block can only be used in next time slot.

Define 2

Signal intensity s_i(t)：s_iT () is the signal intensity of user i mobile terminals when time slot t, it is assumed that a time slot Interior, signal intensity remains constant.

Define 3

Maximum throughput rate Th (s_i(t))：Under certain signal intensity, base station can distribute to user's per time slot Maximum transmitted code check (unit is byte/s), referred to as maximum throughput rate.General signal intensity is bigger, and the data volume that can be transmitted is got over Greatly.If allocated time slot t to user i a width of d of band_i(t) (byte/s), then it is required that d_i(t)≤Th(s_i(t))。

Define 4

Maximum service bandwidth B (t)：Because base station services various applications, Stream Media Application only accounts for a portion, in time slot T can distribute to the bandwidth of Stream Media Application.It is required that

The computational methods of the user buffering time that the present invention is used are as follows：

Define 5

Video playback speed p_i：The data volume of Stream Media Application each time slot mean consumption is referred to as playback rate.

Define 6

Remaining data r_i(t)：When time slot t starts, remaining data volume is referred to as remaining data in user cache, makes r_i(0) =0.

If the data deficiencies in caching is reached, the broadcasting of user will interim card.The remaining data amount of time slot t+1 can basis The situation of previous time slot is calculated, r_i(t+1)=max { (r_i(t)+d_i(t)-tp_i),0}.

Define 7

Buffer time c_i(t)：In time slot t because the data in caching are inadequate, the time for causing user to wait, c is made_i(0)= 0。

Buffer time can be calculated according to remaining data amount, When user has obtained all of data, then the stand-by period of the time slot is 0.Then in time T, all users' is average Stand-by period can be expressed as

Optimization and the limited requirement of service bandwidth based on Consumer's Experience, problem of the invention can be turned in form：

Method for solving based on this optimization problem, the present invention devises the resource allocation algorithm of online Streaming Media bandwidth, I.e. when each time slot starts, according to above formula, the bandwidth resources to base station are allocated, after being assigned, according to point With result data are transmitted to user.The execution cycle of this algorithm is 1s, can change the execution cycle, and basic skills is constant.

The variable used in some algorithms is defined below：

Define 8

Demand data d_need(i)：d_needThe data volume of (i) for needed for maintaining user in next time slot smooth playing；

d_needI the calculating of () is related to data in the caching of user,

Define 9

Data volume d is distributed_sum：d_sumIt is recording parameters, records the allocated amount of bandwidth in algorithm running；

Define 10

Available data d_sup(i)：d_sup(i) be base station meet (1) (2) limited case under, can be carried for user The bandwidth of confession, d_sup(i)=min { Th (s_i(t))-d_i(t),B(t)-d_sum}；

Compared with prior art, the invention provides one kind in mobile cellular net, the Streaming Media of single base station multi-user Using the bandwidth allocation methods of fast cache.Answered when in a mobile cellular net base station range, there are multiple user's request Streaming Medias During data, base station needs distribution bandwidth resource, and the present invention is a kind of bandwidth resources of minimal buffering time in this case Allocation algorithm, the video playback speed according to different user adjusts bandwidth allocation, can efficiently solve single base stations and multiuser Streaming Media bandwidth allocation problems, to obtain user video smooth playing, reduce the interim card and time delay of video as far as possible, improve user's body Test.

Brief description of the drawings

Fig. 1 is deployment schematic diagram of the invention.

Fig. 2 is the bandwidth allocation algorithm flow of Stream Media Application fast cache in the case of single base stations and multiuser of the invention Figure.

Specific embodiment

Describe embodiments of the present invention in detail with reference to the accompanying drawings and examples.

A kind of bandwidth allocation methods of the Stream Media Application fast cache of single base stations and multiuser of the present invention, it is intended to minimize and move The average buffer time of mobile terminal in dynamic Cellular Networks.The agency of the bandwidth allocation algorithm of Stream Media Application fast cache is deployed in Between the base station of Cellular Networks and core net, by collecting the data volume of mobile terminal request, signal intensity, user's stream medium data The parameters such as wear rate, the bandwidth resources to base station are allocated, on the premise of fair and raising bandwidth availability ratio is ensured, The bandwidth that decision-making each terminal should be obtained.Its specific deployment method of operation is as shown in figure 1, the band of Stream Media Application fast cache The controller of allocation algorithm wide is largely divided into four parts：Information receiving module, data transmission module, data reception module is adjusted Degree module.Information receiving module receives and collects the information of mobile terminal, and the bandwidth resources that now base station can provide.Number The data from server are received according to receiver module, waits instruction to be transmitted after caching.Should according to the information Streaming Media collected Performed in scheduler module with the bandwidth allocation algorithm of fast cache, bandwidth of the decision-making to each user distribution.According to bandwidth resources The result of allocation algorithm, data transmission module carries out data transmission.

When signal intensity is different, the data volume that base station can transmit be it is different, Stream Media Application fast cache Bandwidth allocation algorithm is scheduled transmission according to signal intensity and the wear rate of user video to each user in network, and Take into account the fairness of bandwidth allocation.Stream Media Application is a kind of application played when downloading, very sensitive to time delay.Work as caching Data deficiencies when, user terminal take link downloading data.The bandwidth allocation algorithm of Stream Media Application fast cache can be reduced The competition of link, improves the utilization rate of bandwidth, reduces the interim card time of video playback, improves Consumer's Experience.

The bandwidth allocation algorithm of Stream Media Application fast cache is needed according to periodic duty in time-domain, and the moment monitors letter The entrance of the information and user in road is left, and updates the measurement of bandwidth allocation, improves the utilization rate of bandwidth, it is ensured that the justice of user Property, the run time of this bandwidth resource allocation algorithm is typically defined at intervals of a time slot, slot length fixes tentatively t=1s, i.e., often Second updates a bandwidth allocation for base station.If time slot t has N number of user, then the bandwidth allocation of Stream Media Application fast cache is calculated Method needs to be scheduled N number of user.

Above is some general principles that the present invention is based on, specifically, as shown in figure 1, first, in the base station of Cellular Networks Deployment bandwidth allocation is needed to act on behalf of and core net between.Bandwidth allocation acts on behalf of the service bandwidth of periodic collection network flow-medium application B (t), the signal strength information s of each user_i(t), the speed p that each user video is played_i, the stream medium data of user's request Size M_iEtc. information.When mobile subscriber in network (such as cellphone subscriber, PSP user etc.) request stream medium data, in order to Ensure that each user can glibly play video, the buffering and interim card of video, agency's operation Stream Media Application are reduced as best one can The bandwidth allocation algorithm of fast cache, is distribution that Streaming Media user in Cellular Networks carries out Streaming Media bandwidth.Specific method Implemented by following step.

Step one, in time slot t, mobile device i is M to bandwidth allocation proxy requests stream medium data, size_i, agency Record user；If time slot t has user to leave, not request data, bandwidth allocation agency discharges the request of the user, width of not reallocating Bandwidth resources；

Step 2, agency is according to the signal intensity s for collecting user i_i(t), the Mean Speed p that user video is played_i, base station In available streaming media service bandwidth B (t) of this time slot, this time slot is recorded with parameter S and distributes remaining amount of bandwidth, time slot is opened During the beginning, S=B (t) is made；

Step 3, agency is allocated according to the data collected, the bandwidth to user's request now.Initialization, d_i(t) The bandwidth that record agency distributes in time slot t to user i, it is 0, d to assign initial value at first in time slot_i(t) ← 0, i=1, 2,…,N；d_supI () record agency can give the user i maximum bandwidths of distribution in this time slot, assigned at first initially in time slot Be worth is 1, d_sup(i) ← 1, i=1,2 ..., N；Note bandwidth allocation intermediate parameters are designated as d '_iT (), when time slot starts, makes d '_i(t) =d_i(t)；Note bandwidth left amount intermediate parameters are designated as S ', when time slot starts, make S '=S；

Step 4, to the playback rate p of N number of user_iIt is ranked up from small to large, and renumbers, calculates each user Maintain smooth playing to the demand data amount d of next time slot_need(i)；

Step 5, from the 1st user to n-th user, as remaining bandwidth S>When 0, first time bandwidth point is carried out first Match somebody with somebody：

A () calculates now base station can be to the data volume d of user i transmission_sup(i)；

If (b) d_sup(i)3d_needI (), then make d_i(t)=d '_i(t)+d_need(i), S=S '-d_need(i), d_sum=B T ()-S, now updates bandwidth allocation intermediate parameters d '_iT () and remaining bandwidth intermediate parameters S ', makes d '_i(t)=d_i(t), S '= S；

If (c) d_sup(i)<d_need(i), then d_i(t)=d '_i(t)+d_sup(i), S=S '-d_sup(i), d_sum=B (t)-S, Now update bandwidth allocation intermediate parameters d '_iT () and remaining bandwidth intermediate parameters S ', makes d '_i(t)=d_i(t), S '=S；

Wherein d_sumExpression has distributed data volume, is recording parameters；

Step 6, the now system that calculates can be to the data volume d of user i transmission_sup(i)；

Step 7, if now remaining bandwidth S>When 0 and there is d_sup(i) ≠ 0, then by remaining bandwidth allocation to user, From the 1st user to n-th user, the data to user's one time slot of distribution are p every time_i, it is ensured that the fairness of user：

If (a) d_sup(i)≥p_i, then d_i(t)=d ' i (t)+p_i, S=S '-p_i, d_sum=B (t)-S, now updates bandwidth Distribution intermediate parameters d '_iT () and remaining bandwidth intermediate parameters S ', makes d '_i(t)=d_i(t), S '=S；

If (b) d_sup(i)<p_i, then d_i(t)=d '_i(t)+d_sup(i), S=S '-d_sup(i), d_sum=B (t)-S, now Update bandwidth allocation intermediate parameters d '_iT () and remaining bandwidth intermediate parameters S ', makes d '_i(t)=d_i(t), S '=S；Step 8, weight It is new to calculate the data volume d that now system be transmitted to user i_sup(i), if remaining bandwidth S>When 0 and there is d_sup(i)≠ 0, rerun step 7；

Step 9, according to the d of distribution_iT () carries out bandwidth allocation to user present in base station.

Step 10, scheduling enters next time slot, perceives the entrance of user and leaving for user, change of service bandwidth etc., Carry out new round scheduling decision.

Claims (4)

1. a kind of bandwidth allocation methods of Stream Media Application fast cache, it is characterised in that the single base station of Cellular Networks and its Deployment bandwidth allocation is needed to act on behalf of between core net, when mobile subscriber's request stream medium data in network, bandwidth allocation agency It is as follows each user's distribution bandwidth in the base station：

Step one, in time slot t, user i is M to bandwidth allocation proxy requests stream medium data, size_i, bandwidth allocation agency's note Employ family；If time slot t have user leave or user data end of transmission, what bandwidth allocation agency discharged the user please Ask, no longer for it distributes wide bandwidth resource；

Step 2, bandwidth allocation agency collects the signal intensity s of user i_i(t), the Mean Speed p that user video is played_i, base station In available streaming media service bandwidth B (t) of this time slot, this time slot is recorded with parameter S and distributes remaining amount of bandwidth, time slot is opened During the beginning, S=B (t) is made；

Step 3, bandwidth allocation agency is allocated according to the data collected to user's request bandwidth now：Initialization, d_i T bandwidth that () record bandwidth assignment agent is distributed in time slot t to user i, when time slot starts, assigns initial value 0, d_i(t) ← 0, i= 1,2,…,N；d_supI () records bandwidth assignment agent and can start in time slot to the maximum bandwidth of user i distribution in this time slot When, assign initial value 1, d_supI () ← 1, i=1, wherein 2 ..., N, N are user's number；Note bandwidth allocation intermediate parameters are designated as d_i′ T (), when time slot starts, makes d_i' (t)=d_i(t)；Note bandwidth left amount intermediate parameters are designated as S ', when time slot starts, make S ' =S；

Step 4, by the playback rate p of N number of user_iIt is ranked up from small to large, and renumbers, calculates each user and maintain stream Freely it is played to the data volume d that next time slot needs_need(i)；

Step 5, from the 1st user to n-th user, when base station is in the remaining bandwidth S ＞ 0 of this time slot, carries out first time band Width distribution：

A () calculates now bandwidth allocation agency can be to the maximum bandwidth d of user i distribution in this time slot_sup(i)；

If (b) d_sup(i)≥d_needI (), then make d_i(t)=d_i′(t)+d_need(i), S=S '-d_need(i), d_sum=B (t)-S, Now update bandwidth allocation intermediate parameters d_i' (t) and remaining bandwidth intermediate parameters S ', makes d_i' (t)=d_i(t), S '=S；

If (c) d_sup(i) ＜ d_need(i), then d_i(t)=d_i′(t)+d_sup(i), S=S '-d_sup(i), d_sum=B (t)-S, and Update bandwidth allocation intermediate parameters d_i' (t) and remaining bandwidth intermediate parameters S ', makes d '_i(t)=d_i(t), S '=S；

Wherein d_sumExpression has distributed data volume, is recording parameters；

Step 6, calculating now bandwidth allocation agency can be to the maximum bandwidth d of user i distribution_sup(i)；

Step 7, if now remaining bandwidth S ＞ 0 when and there is d_supI () ≠ 0, will carry out the second wheel bandwidth allocation, by residue Bandwidth allocation to user, from the 1st user to n-th user, it is p to distribute the data of a time slot to user every time_i, Ensure the fairness of user：

If (a) d_sup(i)≥p_i, then d_i(t)=d_i′(t)+p_i, S=S '-p_i, d_sum=B (t)-S, and update bandwidth allocation Between parameter d_i' (t) and remaining bandwidth intermediate parameters S ', makes d '_i(t)=d_i(t), S '=S；

If (b) d_sup(i) ＜ p_i, then d_i(t)=d_i′(t)+d_sup(i), S=S '-d_sup(i), d_sum=B (t)-S, and update band Width distribution intermediate parameters d_i' (t) and remaining bandwidth intermediate parameters S ', makes d '_i(t)=d_i(t), S '=S；

Step 8, recalculating now bandwidth allocation agency can be to the maximum bandwidth d of user i distribution_sup(i), if remaining During bandwidth S ＞ 0 and there is d_supI () ≠ 0, rerun step 7；

Step 9, according to the d of distribution_iT () carries out bandwidth allocation to user present in base station；

Step 10, scheduling enters next time slot, perceives the entrance of user and leaving for user, change of service bandwidth etc., carries out New round scheduling decision.

2. bandwidth allocation methods of Stream Media Application fast cache according to claim 1, it is characterised in that the step 4 Middle d_needI () computing formula is：

$d_{need}\left(i\right)=\left\{\begin{array}{cc}{p}_i& r_i\left(t\right)=0\\ p_i-r_i\left(t\right)& 0<r_i\left(t\right)<p_i\left(t\right)\\ 0& r_i\left(t\right)\&GreaterEqual;p_i\left(t\right)\end{array}\right.$

Wherein, r_iT () represents remaining data, when meaning that time slot t starts, remaining data volume, r in user cache_i(0)=0, r_i (t+1)=max { (r_i(t)+d_i(t)-tp_i),0}；

3. bandwidth allocation methods of Stream Media Application fast cache according to claim 1, it is characterised in that the step 5 Middle d_supI () computing formula is：

d_sup(i)=min { Th (s_i(t))-d_i(t),B(t)-d_sum}

Wherein, Th (s_i(t)) represent under certain signal intensity, base station can distribute to the maximum biography of user per time slot Defeated code check, i.e. maximum throughput rate.

4. bandwidth allocation methods of Stream Media Application fast cache according to claim 1, it is characterised in that the d_sup(i) Meet the limitation of following condition (1) and condition (2)：

$\begin{array}{ccc}\min & \stackrel{\&OverBar;}{C}& \\ S.T.& d_i\left(t\right)\&le;\mathrm{Th}\left({\mathrm{signal}}_i\left(t\right)\right)& i=\mathrm{1,2},...,N\\ & & t=\mathrm{0,1},...,T\end{array}---\left(1\right)$

$\underset{i=1}{\overset{N}{\&Sigma;}}{d}_i\left(t\right)\&le;B\left(t\right),t=0,1,...,T---\left(2\right)$

Wherein,Represent in time T, the average stand-by period of all users,c_iT () represents slow Rush the time, c_i(0)=0,