CN105764022A - D2D mode selection method based on cellular network energy transaction - Google Patents

Abstract

The invention discloses a D2D mode selection method based on cellular network energy transaction. The method specifically comprises the following steps: initial energy E0 of DT, distance d between data quantities D0 and DT to be transmitted and a base station, distance r between D2D links, an energy threshold value Eth and a distance threshold value Dth are obtained; when the initial energy is greater than the energy threshold value, all data is transmitted via the D2D links; otherwise which of d and the distance threshold value Dth is greater is determined; when d is greater than the distance threshold value Dth, energy is collected from BS via DT, and the energy is used for sending all data to a D2D receiver; otherwise, a cellular mode is adopted for communication, the initial energy is used by DT to transmit a small amount of key information to BS, and BS searches original data on a current network according to the received key information and then sends the original data to DR; tests show that compared with all strategies that a D2D mode is by all D2D users after electric power is supplied via BS, the D2D mode selection method disclosed in the invention has beneficial effects of small energy consumption, energy efficiency improvement and whole system performance improvement when the same data is transmitted.

Description

A kind of D2D mode selecting method based on cellular network power exchange

Technical field

The invention belongs to wireless communication technology field, more particularly, to a kind of D2D mode selecting method based on cellular network power exchange.

Background technology

In the face of the scarcity of the growth of traffic demand and frequency spectrum resource, energy-saving and emission-reduction, reduce the green communications of power consumption and cause extensive concern gradually as a new generation's theory that communicates.D2D (Device-to-Device, equipment and equipment) communicates and can realize the direct-connected communication of low transmitting power between in-plant communication equipment, thus effectively reducing the energy consumption of user.Need double bounce to forward different to carry out data from traditional cellular communication, D2D communication only needs a jumping to complete data transmission, therefore can realize good single-hop gain, while saving channel resource, reduces communication delay.

In the cellular network comprising D2D communication, D2D user both can carry out direct-connected communication with D2D pattern, it would however also be possible to employ traditional honeycomb mode, carries out data forwarding by base station；If all D2D with adopt per family by BS (BaseStation, base station) power supply carry out communicating of D2D pattern, then user's energy consumption is higher.

Summary of the invention

For disadvantages described above or the Improvement requirement of prior art, the invention provides a kind of D2D mode selecting method based on cellular network power exchange, its object is to reduce the energy consumption of D2D communication in cellular network.

For achieving the above object, according to one aspect of the present invention, it is provided that a kind of D2D mode selecting method based on cellular network power exchange, comprise the following steps:

(1) update the essential information of current network, and obtain the primary power E of DT (D2DTransmitter, D2D transmitter) according to current network information₀, the data volume D of data to be transmitted₀With energy threshold E_th；

Wherein, energy threshold refers to that whole data waiting for transmission are given the least energy required for D2D receiver by direct connected link by D2D transmitter；Corresponding concrete communication scenes, energy threshold sets according to the data volume and tolerable maximum transmitted time delay of intending transmission；

(2) by DT to BS and the DR pilot signal transmitted corresponding to DT；Distance d, DR (D2DReceiver, D2D receiver) that BS obtains between BS and DT according to the path loss of the pilot signal received obtain the direct connected link distance r between DR and DT according to the path loss of the pilot signal received；

(3) the primary power E of DT is judged₀Whether be more than or equal to energy threshold E_th；If so, then by DT, whole data to be transmitted are transmitted directly to DR, otherwise, enter step (4)；

Primary power E₀Be more than or equal to energy threshold E_th, it was shown that total data is enough transferred to DR by D2D direct connected link by the primary power of DT；Directly data waiting for transmission are sent to DR by D2D direct connected link, without base station；Not only reduce the load of base station, and efficiently avoid the double bounce power attenuation that cellular communication brings, thus system capacity consumption is greatly lowered；

Primary power E₀Less than energy threshold E_th, it was shown that DT primary power is not enough, it is impossible to carry out direct-connected communication；

(4) DT is according to above-mentioned direct connected link distance r, obtains the distance threshold D communicating pattern switching_th；

(5) judge that whether the distance d between BS and DT is be more than or equal to described distance threshold D_th, if so, then collected energy by DT from BS, and utilized described energy that whole data waiting for transmission are sent to DR by DT；

If it is not, then adopt honeycomb mode to communicate, DT using primary power to transmit key message to BS, BS obtains data waiting for transmission according to the key message received from current network, and by BS, data waiting for transmission is transmitted to DR；

d≥D_th, it was shown that the distance d between BS and DT is much larger than the distance r between DR and DT, it was shown that the distance approximately equal between distance and BS and the DR between BS and DT；Adopting D2D pattern to carry out direct-connected communication, DT first catches energy necessary to transmission total data from BS, and utilizes this energy by whole data volume D to be sent₀It is sent to DR by D2D direct connected link；

D < D_th, it was shown that the distance between BS and DT is less than distance threshold；Employing honeycomb mode communicates, and DT first transmits key message to BS, BS search, with the key message received, the initial data intending transmission from current network for foundation, and carried out data forwarding by BS.

Preferably, the above-mentioned D2D mode selecting method based on cellular network power exchange, adopt filename or link as key message.

Preferably, the above-mentioned D2D mode selecting method based on cellular network power exchange, its step (2) is specific as follows:

Pilot signal transmitted is distinguished to BS and the DR corresponding to DT by DT；

The distance that BS determines between itself and DT according to path loss after receiving pilot signal

The distance that DR determines between itself and DT according to path loss after receiving pilot signal

Wherein, k is propagation coefficient, and α is path-loss factor, P_tIt is the DT pilot signal power launched, P_{r_BS}It is the BS signal power received, P_{r_DR}It it is the DR signal power received.

Preferably, the above-mentioned D2D mode selecting method based on cellular network power exchange, its step (4) described distance threshold

Wherein, λ is that BS carries out the energy signal wavelength of selection during power transmission.

In general, by the contemplated above technical scheme of the present invention compared with prior art, it is possible to obtain following beneficial effect:

(1) the D2D mode selecting method based on cellular network power exchange provided by the invention, when DT primary power is enough, without base station, directly sends the data to DR by D2D direct connected link；Reduce the load of base station on the one hand, on the other hand, owing to being the direct-connected communication between DT and DR, efficiently avoid the double bounce power attenuation that cellular communication brings, thus system capacity consumption is greatly lowered；

(2) the D2D mode selecting method based on cellular network power exchange provided by the invention, when DT primary power is inadequate, DT can only outwards transmit a small amount of data, therefore according to the distance d between DT and BS and distance threshold D_thMagnitude relationship, communicate the selection of pattern；

When distance between BS and DT is less than distance threshold, i.e. d < D_thTime, adopt honeycomb mode to communicate, DT with extremely low energy to a small amount of key message of base station transmission；From current network being found DT intend the initial data of transmission and be transmitted to DR with key message for clue by base station, the energy expenditure of this communication pattern occurs mainly in BS and forwards data phase；Although the distance between BS and DR is likely larger than the distance between BS and DT, but this communication pattern only has a jumping power attenuation, effectively prevent DT and carries out power transmission and the huge energy loss that brings owing to energy deficiency requires over base station；

Distance approximately equal between distance and BS and DR between BS and DT, the distance d between BS and DT is more than distance threshold, when DT and BS wide apart, i.e. d >=D_thTime, adopt D2D pattern to carry out direct-connected communication, DT collect energy from BS, and utilize this energy by total data amount D₀It is sent to DR；Although this communication pattern can produce double bounce power attenuation, but power attenuation amount is much larger than the power attenuation amount produced with equidistant lower RF power during due to direct connected link distance relatively close and telecommunication, compared to the communication strategy being forwarded total data by BS, during transmission same quantity of data, the energy that this scheme consumes is relatively low, embodies the near field advantage of the direct-connected communication of D2D further；

On the whole, the above technical scheme D2D all with prior art that the present invention proposes powers compared with the method carrying out D2D pattern communication by base station with selecting per family, it has the beneficial effect of energy efficiency of optimization system near field, can promote the performance of whole network.

Accompanying drawing explanation

Fig. 1 is the beehive network system model schematic comprising D2D user in embodiment；

Fig. 2 is the flow chart of the D2D mode selecting method based on cellular network power exchange of embodiment of the present invention confession；

Fig. 3 is the Energy Consumption Simulation comparison diagram of the method carrying out D2D pattern by BS after method and all D2D users of embodiment all select to be powered；

Fig. 4 is as d < D in embodiment_thTime, the graph of a relation of energy consumption and transmission data.

Detailed description of the invention

In order to make the purpose of the present invention, technical scheme and advantage clearly understand, below in conjunction with drawings and Examples, the present invention is further elaborated.Should be appreciated that specific embodiment described herein is only in order to explain the present invention, is not intended to limit the present invention.As long as just can be mutually combined additionally, technical characteristic involved in each embodiment of invention described below does not constitute conflict each other.

D2D mode selecting method based on cellular network power exchange provided by the invention, according to the distance d between DT and BS and distance threshold D_thMagnitude relationship, communicate the selection of pattern: as d >=D_thTime, adopt D2D pattern to carry out direct-connected communication, otherwise, adopt honeycomb mode to communicate；There is the effect reducing transmission energy consumption.

Shown in Fig. 1, it it is the beehive network system model schematic comprising D2D user in embodiment；Wherein, D2D user both can adopt D2D pattern to carry out direct-connected communication, it is also possible to selects traditional honeycomb mode, carries out data forwarding by base station；In embodiment, all base stations and D2D user obey independent Poisson distribution, the characteristic according to Poisson distribution, and the geometric properties of any community is all consistent with one of them community, and the analysis conclusion of one of them community can expand to all communities in cellular network.

Shown in Fig. 2, it is the flow chart of the D2D mode selecting method based on cellular network power exchange of embodiment confession, specifically includes following steps:

(1) carry out system initialization, DT update the essential information of current network, and obtain the primary power E of DT according to current network information₀, wait data volume D waiting for transmission₀And energy threshold E_th；In embodiment, energy threshold E_thIt it is 100 joules；

(2) by DT to corresponding BS and DR pilot signal transmitted；When BS and DR receives pilot signal, determine the distance r between distance d and DR and the DT between BS and DT according to the path loss of pilot signal；

(3) DT is by primary power E₀With energy threshold E_thCompare, if E₀≥E_th, it was shown that primary power is enough to DT and total data is transmitted directly to DR；If E₀< E_th, then step (4) is entered；

(4) DT obtains the distance threshold D communicating pattern switching according to D2D direct connected link distance r_th；

(5) by the distance d between BS and DT and distance threshold D_thCompare, as d >=D_thTime, adopt D2D pattern to carry out direct-connected communication, namely DT collects energy from BS, and utilizes this energy directly by total data amount D₀It is sent to DR；

Otherwise, adopting honeycomb mode to communicate, namely DT uses primary power to transmit a small amount of key message to BS, and BS searches the initial data intending transmission according to the key message received from current network, and forwards it to DR.

In embodiment, using D2D transmitter DT as the node in network, when its primary power be not enough to transmit all intend transmission data time, by catching energy from base station to maintain the transmission of corresponding data；When DT is from time close to base station, DT utilizes relatively low primary power that the key message needing the data of transmission is sent to BS, BS and searches, according to the key message received, initial data that plan transmits in current network and forward it to DR；Adopt link as key message in embodiment.

Shown in Fig. 3, it is carry out compared with the method for D2D communication after the D2D mode selecting method that embodiment provides all selects with all D2D users to be powered by BS, both Energy Consumption Simulation comparison diagrams；Wherein, parameter is: DT primary power E₀The energy threshold E of the direct-connected communication of=10J, D2D_th=100J, intends the data volume D of transmission₀=50Mbit, bandwidth W=1MHz, path-loss factor α=4, the fixed transmission powers P of BS_BS=100W, BS carry out the length r=2m that energy signal wavelength is λ=0.1m, D2D link of selection during RF power；In an embodiment, DT to BS transmit the energy that consumes of key message for the energy that transmission total data consumes very little, negligible.

As can be seen from Figure 3: ining contrast to all D2D with adopting the BS method carrying out D2D pattern communication after powering per family, the D2D mode selecting method that embodiment provides can optimize system power consumption, improves the energy efficiency of whole network.

Shown in Fig. 4, it is as d < D_thTime, the D2D mode selecting method that embodiment provides adopts the energy consumption comparison figure of the scheme carrying out direct-connected communication of being powered by base station per family with all D2D use；Wherein, parameter is: DT primary power E₀The energy threshold E of the direct-connected communication of=10J, D2D_th=100J, bandwidth W=1MHz, path-loss factor α=4, the fixed transmission powers P of BS_BS=100W, BS carry out the distance d=400m between length r=2m, DT and the BS that energy signal wavelength is λ=0.1m, D2D link of selection during RF power.

As can be seen from Figure 4: as d < D_thTime, when transmitting identical data volume, carry out the energy that cellular communication consumes and be less than to be powered by base station by transmitting key message to BS and carry out the scheme of the direct-connected communication of D2D.

Those skilled in the art will readily understand; the foregoing is only presently preferred embodiments of the present invention; not in order to limit the present invention, all any amendment, equivalent replacement and improvement etc. made within the spirit and principles in the present invention, should be included within protection scope of the present invention.

Claims (4)

1. the D2D mode selecting method based on cellular network power exchange, it is characterised in that comprise the steps:

(1) the primary power E of DT is obtained according to current network information₀, the data volume D of data to be transmitted₀With energy threshold E_th；

(2) by DT to BS and DR pilot signal transmitted；Distance d, DR that BS obtains between BS and DT according to the path loss of the pilot signal received obtain the direct connected link distance r between DR and DT according to the path loss of the pilot signal received；

(3) the primary power E of DT is judged₀Whether be more than or equal to energy threshold E_th, if so, then by DT, data waiting for transmission are transmitted directly to DR；If it is not, then enter step (4)；

(4) the distance threshold D communicating pattern switching is obtained according to described direct connected link distance r_th；

(5) judge that whether the distance d between BS and DT is be more than or equal to described distance threshold D_th, if so, then collected energy by DT from BS, and utilized described energy that data waiting for transmission are sent to DR by DT；

If it is not, then utilized primary power to send key message to BS by DT, and from current network, obtained data waiting for transmission by BS according to described key message, and described data waiting for transmission are transmitted to DR.

2. D2D mode selecting method as claimed in claim 1, it is characterised in that adopt filename or link as key message.

3. D2D mode selecting method as claimed in claim 1 or 2, it is characterised in that described step (2) is specific as follows:

(2.1) pilot signal transmitted is distinguished by DT to BS and DR；

(2.2) distance that BS determines between BS and DT according to path loss after receiving pilot signal

$d={\left(\frac{{\mathrm{kP}}_t}{P_{r\_\mathrm{BS}}}\right)}^{\frac{1}{\mathrm{\&alpha;}}};$

(2.3) distance that DR determines between DR and DT according to path loss after receiving pilot signal

Wherein, k is propagation coefficient, and α is path-loss factor, P_tIt is the DT pilot signal power launched, P_{r_BS}It is the BS signal power received, P_{r_DR}It it is the DR signal power received.

4. D2D mode selecting method as claimed in claim 1 or 2, it is characterised in that described distance threshold

Wherein, λ is that BS carries out the energy signal wavelength of selection during power transmission.