CN106686679A - Multihop D2D route hop count limiting method based on energy efficiency in content center network - Google Patents

Abstract

The invention discloses a multihop D2D route hop count limiting method based on energy efficiency in a content center network. The method comprises the following steps of 1) calculating lowest energy consumption PD2Dmin, ij needed by a source user terminal i which acquires a data content from a target user terminal j through a multihop D2D communication mode under an ideal condition, and calculating energy consumption PDL, i during communication between the source user terminal i and a base station; 2) when the PD2Dmin, ij is greater than the PDL, i, acquiring the data content through direct communication between the source user terminal i and the base station, and when the PD2Dmin, ij is less than or equal to the PDL, i, jumping to a step3; 3) setting a maximum routing hop count Hoplimit based on time delay, calculating a minimum routing hop count Hoplower, ij among users based on a distance, and then calculating and acquiring a maximum hop count Hopmax, ij of the user based on energy efficiency; 4) calculating a shortest-path multi-hop D2D route; and 5) calculating energy consumption PD2D, ij of the source user terminal i which acquires the data content from the target user terminal j through the shortest-path multi-hop D2D route, and then according to the PD2D, ij and the PDL, i, reading the data content. By using the method, effectiveness of establishing the multi-hop D2D route can be effectively increased, energy efficiency of the system is low and system overheads are low.

Description

Multi-hop D2D hop count method for limiting based on efficiency in content center network

Technical field

The invention belongs to the network technique field in cordless communication network, it is related to be based on efficiency in a kind of content center network Multi-hop D2D hop count method for limiting.

Background technology

Due to the fast development of multimedia application, the data traffic demand of mobile network is experiencing blowout growth, And most mobile flow is all consumed on video resource.In view of future network be more using content as center, Content center network is proposed, it refers to user and is concerned with content in itself rather than the position of content, and D2D is content center The important component of network, it can set up the content that respective caching is shared in connection between user.

In D2D communications, what data traffic need not directly be transmitted by base station but between user, it can reduce biography Delivery of energy consumption and the interference that other are linked.Additionally, for some Hot Contents, repeatedly please by many users within certain time period Ask, these Hot Contents can be buffered in the user terminal that some have obtained the content from base station, by D2D communication parties Formula is user's transmission information of other request identical contents, can substantially reduce the load pressure of base station back haul link.Additionally, working as Preceding social networks Showed Very Brisk, having the content much issued in social networks is produced by smart mobile phone or wireless device , it is exactly to produce other users around content user that there is significant portion in colony interested in these contents, and these users are complete Content information can be obtained from the user terminal of content is produced by D2D communication modes entirely, be gone without each user Obtained from base station end.

Current D2D researchs focus mostly in the short-range direct communication of single-hop, also there is what small part communicated on multi-hop D2D Research, for multi-hop D2D communications, primary is to set up multihop routing, and because the communication between user typically has time delay to limit, Simultaneously time delay again with hop count into positive correlation, hop count is more, and time delay is bigger, and in general, D2D communications can save energy Consumption, improves efficiency, but for multi-hop D2D communications, energy consumption is closely related with D2D hop counts, it is anticipated that work as route When hop count exceedes certain value, the energy consumption that user obtains content under D2D communication patterns will be greater than by needed for base station acquisition content Energy consumption, in the communication pattern selection based on efficiency, such route belongs to invalid route and will be rejected, and is setting up this During a little invalid routes, increased overhead and each as via node energy consumption, it is therefore desirable to design one kind Method, can effectively improve the validity of multi-hop D2D routes, reduce the expense of system, improve system energy efficiency.

The content of the invention

Shortcoming it is an object of the invention to overcome above-mentioned prior art, there is provided energy is based in a kind of content center network The multi-hop D2D hop count method for limiting of effect, the method can effectively improve the validity for setting up multi-hop D2D routes, and The efficiency of system is higher, and overhead is relatively low.

To reach above-mentioned purpose, the multi-hop D2D hop counts based on efficiency are limited in content center network of the present invention Method processed is comprised the following steps：

1) source user terminal i under ideal conditions is calculated to be obtained from purpose user terminal j by multi-hop D2D communication modes Lowest energy consumption needed for data contentAnd calculate energy consumption P when being communicated between source user terminal i and base station_DL,i；

2) whenThen source user terminal i directly obtains data content with base station communication, completes content center net The multi-hop D2D hop counts based on efficiency are limited in network, whenThen go to step 3)；

3) the maximum hop count Hop based on time delay is set_limit, calculate minimum hop count between the user based on distance Hop_lower,ij, then in [Hop_lower,ij,Hop_limit] in the range of be calculated user be based on efficiency maximum hop count Hop_max,ij；

The multi-hop D2D routes set up between source user terminal i and purpose user terminal j, obtain shortest path multi-hop D2D roads By, wherein, when any one multi-hop D2D route hop count reach default maximum hop count when still without achieve the goal user terminal j when, Then give up multi-hop D2D routes；

Calculate source user terminal i and the energy that data content is obtained from purpose user terminal j is route by shortest path multi-hop D2D Consumption P_D2D,ij, work as P_D2D,ij≥P_DL,iWhen, then source user terminal i obtains data content by way of being communicated between base station, complete The multi-hop D2D hop counts based on efficiency are limited into content center network；Work as P_D2D,ij＜ P_DL,iWhen, source user terminal i is then led to Cross shortest path multi-hop D2D routes and data content is obtained from purpose user terminal j, complete to be based on efficiency in content center network Multi-hop D2D hop counts limitation.

If being communicated by multi-hop D2D communication modes between source user terminal i and purpose user terminal j, data are transmitted The via node that the multi-hop D2D of content is routed through being distributed between source user terminal i and purpose user terminal j reaches purpose use Family terminal j, then multi-hop D2D power of communications loss model be：

Wherein, P_D2DIt is the power attenuation of multi-hop D2D communications, P_activityIt is circuit power consumption of the terminal in active state, P_Dtx,kIt is the transmission power of via node k, P_Drv,kIt is the power consumption of via node k receive information post-processing informations.

Calculate source user terminal i and the energy that data content is obtained from purpose user terminal j is route by shortest path multi-hop D2D Consumption P_D2D,ijConcrete operations be：

Theoretic lowest energy consumption value during using limit approach estimation source user terminal i selection D2D multi-hop communication modes, if There are some other user terminals as via node between source user terminal i and purpose user terminal j, each relaying section The performance number that point processing information is consumed is P_Drv, and each jump link has identical receiving power in multi-hop D2D routes The distance between γ, via node k and via node k+1 are d_k, D_D2D,ijFor between source user terminal i and purpose user terminal j Air line distance, then have

Bring formula (11) into formula (10), obtain

d_k≤r (15)

Wherein,

Obtained according to formula (12), (13), (14) and (15)When it is whole The transmission power total energy consumption of link is minimum, therefore

If continuous variable x represents that hop count K, f (x) as the function of hop count, then have

F (x)=Δ P+ (x-1) (Δ P+P_Drv)+γD_D2D ^αx^1-α (17)

If 2≤α≤4, f (x) is carried out into derivation to x, obtained

If source user terminal i can obtain data content, root by multi-hop D2D communication modes from purpose user terminal j According to the air line distance D between source user terminal i and purpose user terminal j_D2D,ijMinimum hop count between the user of distance must be based on Hop_lower,ijFor：

In [Hop_lower,ij,Hop_limit] in the range of using dichotomy be calculated user be based on efficiency maximum hop count Hop_max,ij。

The invention has the advantages that：

The multi-hop D2D hop count method for limiting based on efficiency is in concrete operations in content center network of the present invention In, when judging that source user terminal chooses whether to attempt setting up multi-hop D2D routes, calculate source user terminal under ideal conditions Lowest energy consumption needed for obtaining data content from purpose user terminal by multi-hop D2D communication modesAnd calculate source use Energy consumption P when being communicated between family terminal and base station_DL,i, only whenWhen, just attempt in source user terminal and purpose Multi-hop D2D routes are set up between user terminal, so as to effectively reject the source user terminal trial that part is unsatisfactory for efficiency requirement The multi-hop D2D routes of foundation, reduce the foundation of invalid route；In addition, for the source user for allowing to attempt setting up multi-hop D2D routes Terminal, by minimum hop count Hop between the maximum hop count limitation based on time delay and the user based on distance_lower,ijTwo factors Limited, the maximum hop count that user is based on efficiency is then calculated again；Attempt setting up multi-hop D2D routes in source user terminal When, when any one multi-hop D2D route hop count reach default maximum hop count when still without achieve the goal user terminal when, then give up Multi-hop D2D route, so as to further reduce the foundation of invalid multi-hop D2D routes；That is set up only in maximum hop count is more Jumping D2D routes could enter in final decision, in final decision, by reference source user terminal in shortest path multi-hop D2D The energy consumption P of data content is obtained under route from purpose user terminal_D2D,ijEnergy consumption when being communicated between source user terminal and base station P_DL,iBetween the relation selection relatively low mode of energy consumption carry out the acquisition of data content so that final choice goes out the minimum side of energy consumption Formula is communicated, and the present invention greatly improves the validity of the multi-hop D2D routes that user is set up by screening twice, improves The efficiency of system, it is to avoid meaningless energy dissipation, while the expense of the system of reduction, and then greatly improve content center network Systematic function, is with a wide range of applications.

Brief description of the drawings

Fig. 1 is the flow chart of dichotomy in the present invention；

Fig. 2 is systematic schematic diagram of the invention.

Specific embodiment

The present invention is described in further detail below in conjunction with the accompanying drawings：

With reference to Fig. 2, the multi-hop D2D hop count method for limiting bags based on efficiency in content center network of the present invention Include following steps：

1) source user terminal i under ideal conditions is calculated to be obtained from purpose user terminal j by multi-hop D2D communication modes Lowest energy consumption needed for data contentAnd calculate energy consumption P when being communicated between source user terminal i and base station_DL,i；

2) whenThen source user terminal i directly obtains data content with base station communication, completes content center net The multi-hop D2D hop counts based on efficiency are limited in network, whenThen go to step 3)；

3) the maximum hop count Hop based on time delay is set_limit, calculate minimum hop count between the user based on distance Hop_lower,ij, then in [Hop_lower,ij,Hop_limit] in the range of be calculated user be based on efficiency maximum hop count Hop_max,ij；

The multi-hop D2D routes set up between source user terminal i and purpose user terminal j, obtain shortest path multi-hop D2D roads By, wherein, when any one multi-hop D2D route hop count reach default maximum hop count when still without achieve the goal user terminal j when, Then give up multi-hop D2D routes；

Calculate source user terminal i and the energy that data content is obtained from purpose user terminal j is route by shortest path multi-hop D2D Consumption P_D2D,ij, work as P_D2D,ij≥P_DL,iWhen, then source user terminal i obtains data content by way of being communicated between base station, complete The multi-hop D2D hop counts based on efficiency are limited into content center network；Work as P_D2D,ij＜ P_DL,iWhen, source user terminal i is then led to Cross shortest path multi-hop D2D routes and data content is obtained from purpose user terminal j, complete to be based on efficiency in content center network Multi-hop D2D hop counts limitation.

Step 1) in, by the average power consumption P of base station m_mThe linear function of average emitted power is modeled as, wherein,

P_m=a_mP_tx+b_m+c_m (1)

Wherein, P_txIt is the average emitted power of base station m, a_mIt is power attenuation degree, b_mBe due to base station m process signals and Base station cools down consumed power, c_mIt is the power attenuation by back haul link Optical Fiber Transmission data.

Base station from heterogeneous network back haul link obtain content when, heterogeneous network back haul link can power loss, then have

P=P_m+P_bh (2)

Wherein, P_bhIt is heterogeneous network back haul link power attenuation, P is the active loss power of base station.

When heterogeneous network back haul link power consumption refers to user to macro base station request service, content of the base station according to user's request The power that corresponding content is consumed is obtained from core net by heterogeneous network back haul link；And for D2D communications, due to it Communication process need not obtain content from core net, so also without by this process of heterogeneous network back haul link, macro base station backhaul Link energy consumptionIt is modeled as

Wherein, max_dlIt is maximum downstream interface number on the aggregation switch of macro base station end, P_sIt is aggregation switch Power consumption, P_dlIt is the power attenuation for receiving single downstream interface on the macro base station aggregation switch of backhaul link flow, I_ulFor The total number of upstream Interface, P_ulIt is the power attenuation of single upstream Interface；

The total number I of upstream Interface_ulFor：

Wherein, C_aggIt is the total flow in aggregation switch on macro base station, T_maxIt is a maximum transmitted for upstream switch Speed, then the power consumption P of aggregation switch_sFor：

Wherein, P_maxIt is the maximum power dissipation of interchanger,Be aggregating switching function carry maximum stream flow, α be weight because Son；

Assuming that in the content in heart network, the distance between two users are d_e, by one by K-1 between two users The multihop routing of via node transmits data, and the i-th repeater span jumped is d_i, then have

Wherein, P_outIt is transmission output power, η is path attenuation coefficient, and β represents the constant of antenna performance.

Assuming that being communicated by multi-hop D2D communication modes between source user terminal i and purpose user terminal j, number is transmitted The via node for being routed through being distributed between source user terminal i and purpose user terminal j according to the multi-hop D2D of content reaches purpose User terminal j, then multi-hop D2D power of communications loss model can be modeled as：

Wherein, P_D2DIt is the power attenuation of multi-hop D2D communications, P_activityThe circuit work(for being terminal device in active state Consumption, P_Dtx,kIt is the transmission power of via node k, P_Drv,kIt is the power consumption of node k receive information post-processing informations.

The extra power consumed when selecting two kinds of different communication modes concern is primarily with source user terminal i in the present invention Rate, due to no matter selecting which kind of mode communicates, source user terminal i consumption power it is identical, therefore source user terminal i power consumption not Take into account, additionally, terminal device circuitry power damage can be increased when source user terminal i is from idle state transition into active state Consumption.Source user terminal i obtains power that request content consumed from purpose user terminal j by multi-hop D2D communication modes can It is expressed as

Δ P=P_activity-P_idle(9)

Wherein, P_idleIt is circuit power consumption of the terminal device in idle condition.

Theoretic lowest energy consumption value when estimating source user terminal i selection D2D multi-hop communication modes using limit approach, It is located between source user terminal i and purpose user terminal j and there are some other user terminals as via node, each relaying The performance number P that node processing information is consumed_Drv, and each jump link has identical receiving power in multi-hop D2D routes γ；The distance between via node k and via node k+1 is d_k, D_D2D,ijFor between source user terminal i and purpose user terminal j Air line distance, then have

Bring formula (11) into formula (10), obtain

d_k≤r (15)

Wherein,

Obtained according to formula (12), (13), (14) and (15)When it is whole The transmission power total energy consumption of individual link is minimum, therefore

If continuous variable x represents that hop count K, f (x) as the function of hop count, then have

F (x)=Δ P+ (x-1) (Δ P+P_Drv)+γD_D2D ^αx^1-α (17)

If 2≤α≤4, f (x) is carried out into derivation to x, obtained

Can be drawn under ideal conditions by formula (18), the lowest power value consumed using multi-hop D2D communication patterns, because This, if other user terminals are cached with the content of source user terminal i request, attempts by setting up multi-hop D2D between two users Before route, system estimates power consumption P of the source user terminal i by base station communication respectively_DL,iAnd the lowest power consumption communicated by D2DIfShow that source user terminal i can attempt being set up and purpose user terminal j between multi-hop D2D and lead to Whether letter route to obtain request content, but finally selects D2D patterns, in addition it is also necessary to judged according to the actual energy consumption routeing； WhenIf then its actual power consumption values of expression source user terminal i selection D2D communication patterns are higher than necessarily base station communication Pattern, in the communication pattern decision-making based on efficiency, source user terminal i directly selects base station communication mode, and need not go to attempt Set up multi-hop D2D communication lines by, so as to substantially reduce user in network attempt setting up multi-hop D2D communication lines by number of times, reduce Overhead and energy dissipation.

For the content center network being made up of base station and user terminal, each base station in content center network can be pre- First estimate in its coverage, when between any two user terminal on all positions by D2D pattern communications most Low energy consumption, while can also estimate for the user on optional position, energy consumption during selection base station communication mode；These information will be by In the base station for pre-depositing, when user decides whether that D2D routes are set up in trial, base station is according to user current location and is cached with The user terminal location of request content, inquires about prestored information, and directly can be sent to the user for initiating request allows or forbid D2D route signalings are set up in trial.

The overall delay that data are transmitted in the wireless network is by treatment time delay, queuing delay, transmission delay and propagation delay group Into in D2D multi-hop communications, only at a distance of several meters to tens meters between two equipment of each jump, propagation delay is to network delay Influence can be ignored；Treatment time delay, queuing delay and transmission delay are directly proportional to hop count, therefore can use Hop count represents time delay, so as to the D2D communication issues of delay constraint to be translated into the D2D communication issues of hop count constraint.

When D2D hop counts exceed predetermined threshold value, the energy consumption of D2D communications will be with increasing for hop count and increase, because This, when D2D hop counts exceed maximum hop count, the energy consumption of D2D communications can will be carried out more than user's selection base station mode all the time The energy consumption of communication；When D2D hop counts are less than or equal to maximum hop count, user is possible to be less than by the energy consumption that D2D communicates Base station communication.

If Hop_limitIt is the D2D communication maximum hop counts by communication delay, works as D_D2D,ij≥Hop_limitDuring r, source user terminal i Base station communication mode is directly selected, works as D_D2D,ij<Hop_limitR, then willWith P_DL,iIt is compared, whenWhen, then show Hop_limitAlso the limited condition of efficiency, Hop are met_limitIt is exactly that D2D communicates hop count most Big admissible hop count；WhenWhen, then illustrate that the D2D communication lines for being limited to efficiency are less than by maximum hop count Hop_limit, to avoid source user terminal i during attempting setting up route, hop count is permitted more than the maximum for being limited to efficiency Perhaps hop count, then need to find out all position users that maximum can allow D2D hop counts in a variety of situations.

If source user terminal i can obtain request content, root by multi-hop D2D communication patterns from purpose user terminal j According to the air line distance D between source user terminal i and purpose user terminal j_D2D, minimum route is jumped between ij obtains the user based on distance Number Hop_lower,ij：

Because the maximum hop count that D2D communications are limited to time delay is Hop_max,ij, therefore efficiency limitation is extended to when meeting simultaneously The scope for routeing maximum hop count is [Hop_lower,ij,Hop_limit]；Between estimating each user using dichotomy on this basis D2D route maximum allowable hop count Hop_max,ij；

When source user terminal i attempt set up D2D multihop routings during, if through permission maximum hop count after still Without purpose user terminal j is reached, then terminate route and continue to be transmitted to next node, and remove this route.

Claims (6)

1. the multi-hop D2D hop count method for limiting of efficiency is based in a kind of content center network, it is characterised in that including following Step：

1) calculate source user terminal i under ideal conditions and data are obtained from purpose user terminal j by multi-hop D2D communication modes Lowest energy consumption needed for contentAnd calculate energy consumption P when being communicated between source user terminal i and base station_DL,i；

2) whenThen source user terminal i directly obtains data content with base station communication, in completion content center network Multi-hop D2D hop counts limitation based on efficiency, whenThen go to step 3)；

3) the maximum hop count Hop based on time delay is set_limit, calculate minimum hop count between the user based on distance Hop_lower,ij, then in [Hop_lower,ij,Hop_limit] in the range of be calculated user be based on efficiency maximum hop count Hop_max,ij；

The multi-hop D2D routes set up between source user terminal i and purpose user terminal j, obtain shortest path multi-hop D2D routes, its In, when any one multi-hop D2D route hop count reach default maximum hop count when still without achieve the goal user terminal j when, then give up Abandon multi-hop D2D routes；

Calculate source user terminal i and the energy consumption that data content is obtained from purpose user terminal j is route by shortest path multi-hop D2D P_D2D,ij, work as P_D2D,ij≥P_DL,iWhen, then source user terminal i obtains data content by way of being communicated between base station, completes The multi-hop D2D hop counts based on efficiency are limited in content center network；Work as P_D2D,ij＜ P_DL,iWhen, source user terminal i then passes through Shortest path multi-hop D2D route and data content is obtained from purpose user terminal j, completes to be based on efficiency in content center network Multi-hop D2D hop counts are limited.

2. the multi-hop D2D hop count method for limiting of efficiency is based in content center network according to claim 1, and it is special Levy and be, if being communicated by multi-hop D2D communication modes between source user terminal i and purpose user terminal j, in transmission data The via node that the multi-hop D2D of appearance is routed through being distributed between source user terminal i and purpose user terminal j reaches purpose user Terminal j, then multi-hop D2D power of communications loss model be：

$P_{D2D}=(K+1)P_{activity}+\underset{k=2}{\overset{K+1}{\&Sigma;}}{P}_{Dtx,k}+\underset{k=1}{\overset{K}{\&Sigma;}}{P}_{Drv,k}---\left(7\right)$

Wherein, P_D2DIt is the power attenuation of multi-hop D2D communications, P_activityIt is circuit power consumption of the terminal in active state, P_Dtx,kFor The transmission power of via node k, P_Drv,kIt is the power consumption of via node k receive information post-processing informations.

3. the multi-hop D2D hop count method for limiting of efficiency is based in content center network according to claim 2, and it is special Levy and be, calculate source user terminal i and the energy that data content is obtained from purpose user terminal j is route by shortest path multi-hop D2D Consumption P_D2D,ijConcrete operations be：

Theoretic lowest energy consumption value during using limit approach estimation source user terminal i selection D2D multi-hop communication modes, is located at source There are some other user terminals as via node between user terminal i and purpose user terminal j, at each via node The performance number that reason information is consumed is P_Drv, and each jump link has identical receiving power γ in multi-hop D2D routes, The distance between via node k and via node k+1 is d_k, D_D2D,ijFor between source user terminal i and purpose user terminal j Air line distance, then have

$P_{D2D,ij}=K\mathrm{\&Delta;}P+\underset{k=2}{\overset{K+1}{\mathrm{\&Sigma;}}}{P}_{Dtx,k}+(K-1)P_{Drv}---\left(10\right)$

$P_{Dtx,k}{d}_k^{-\mathrm{\&alpha;}}=\mathrm{\&gamma;}---\left(11\right)$

Bring formula (11) into formula (10), obtain

$P_{D2D,ij}=\mathrm{\&Delta;}P+(K-1)(\mathrm{\&Delta;}P+P_{Drv})+\mathrm{\&gamma;}\underset{k=2}{\overset{K+1}{\&Sigma;}}{d}_k^{\mathrm{\&alpha;}}---\left(12\right)$

$\underset{\stackrel{\&OverBar;}{d}}{min}{P}_{D2D,ij}---\left(13\right)$

$\begin{array}{cc}s.t& \underset{k=2}{\overset{K+1}{\mathrm{\&Sigma;}}}{d}_k=D_{D2D,ij}\end{array}---\left(14\right)$

d_k≤r (15)

Wherein,

4. the multi-hop D2D hop count method for limiting of efficiency is based in content center network according to claim 3, and it is special Levy and be, obtained according to formula (12), (13), (14) and (15)When it is whole The transmission power total energy consumption of link is minimum, therefore

If continuous variable x represents that hop count K, f (x) as the function of hop count, then have

F (x)=Δ P+ (x-1) (Δ P+P_Drv)+γD_D2D ^αx^1-α (17)

If 2≤α≤4, f (x) is carried out into derivation to x, obtained

5. the multi-hop D2D hop count method for limiting of efficiency is based in content center network according to claim 3, and it is special Levy and be, if source user terminal i can obtain data content by multi-hop D2D communication modes from purpose user terminal j, according to Air line distance D between source user terminal i and purpose user terminal j_D2D,ijMinimum hop count between the user of distance must be based on Hop_lower,ijFor：

6. the multi-hop D2D hop count method for limiting of efficiency is based in content center network according to claim 1, and it is special Levy and be, in [Hop_lower,ij,Hop_limit] in the range of using dichotomy be calculated user be based on efficiency maximum hop count Hop_max,ij。