CN105451315A - Serial energy acquisition method with characteristic of throughput maximization - Google Patents

Abstract

The invention discloses a serial energy acquisition method with characteristic of throughput maximization. The method comprises the steps: step one, network initialization; step two, initial network transmission; step three, optimal network time distribution; and step four, network transmission. According to the invention, the signal energy of uplinks and downlinks of user nodes can be collected reasonably; a time distribution scheme of information transmission and energy collection between user nodes can be optimized effectively; the energy collection efficiency of the user node of the network can be improved; and an objective of network throughput maximization can be achieved.

Description

Throughput-maximized serial energy-collecting method

Technical field

The present invention relates to the information transmission under a kind of cordless communication network and energy-collecting method, particularly relate to a kind of throughput-maximized serial energy-collecting method, belong to wireless power technical field of communication network.

Background technology

The wireless power communication technology is the important research field in present communications subject, is proposed the earliest, derived multiple research direction through development for many years by the father tesla of alternating current, and wherein electromagnetic induction is current modal wireless charging scheme.Wireless communication system take then electromagnetic wave as transmission medium, achieves effective transmission of telecommunications breath.For this feature, VarshneyLavR. in 2008 IEEEInternationalSymposiumonInformationTheory publish thesis " Transportinginformationandenergysimultaneously " show to compromise and realize radio communication and power delivery.2010, GroverPulkit and SahaiAnant IEEEInternationalSymposiumonInformationTheoryProceedings publish thesis " shannonmeetstesla:wirelessinformationandpowertransfer " show also can obtain the dual gain of information and Energy Transfer in frequency-selective channel simultaneously.Subsequently, people expand research for the method realizing radio communication and electrical transfer simultaneously, JuHyungsik published thesis " ThroughputMaximizationinWirelessPoweredCommunicationNetw orks " in 2014 at IEEETransactionsonWirelessCommunications, the document gives optimal time allocative decision, achieves this wireless power communication network uplink throughput and maximizes.But the method only considers the transmission plan of each user node from Integrated access point collecting energy, does not study the situation of energy acquisition between user node.

Under considering proximity condition, between wireless power network neighboring user node, implement the situation that collecting energy may be better than implementing from remote accessing point energy acquisition.For this reason, the present invention is based on throughput-maximized criterion, design a kind of new particle group optimizing wireless power communication network transmission method, the time devided modulation scheme of information transmission and energy acquisition between effective optimizing user node, improve network user node energy acquisition efficiency, reach the object of optimized network throughput.

Summary of the invention

The object of the present invention is to provide a kind of throughput-maximized serial energy-collecting method, by being optimized distribution to the time of information transmission and energy acquisition, effectively improving network energy collecting efficiency, realizing network uplink throughput-maximized.

Object of the present invention is achieved by the following technical programs:

A throughput-maximized serial energy-collecting method, the method comprises the following steps:

1. netinit, disposes K+1 node; Numbering 0 is Integrated access point, and numbering 1 ~ K is user node; It is P that Integrated access point has firm power ₀watt, user node initial power is 0 watt; Integrated access point 0 and the total communication time of all K user node are T second, are 0 ~ K peer distribution initialization time t at random ₀t, t ₁t ..., t _kt; Wherein, t _ifor time devided modulation weight (i=0,1 ..., K), and t ₀+ t ₁+ ... + t _k=1, make t=[t ₀t ₁t _k];

2. network initial transmission

1) down link energy acquisition: Integrated access point is at time t ₀with power P in T ₀continue to send down link signal x ₀, each user node is at time t ₀the down link signal x that in T, continuous reception Integrated access point sends ₀, gather and store this signal energy; A kth user node Received signal strength is y _k=h _{k, 0}x ₀+ z _k(k=1 ..., K), wherein, h _{k, 0}for Integrated access point 0 is to the channel condition information of a kth user node, z _kfor additive white Gaussian noise;

2) uplink energy collection and information transmission: a kth user node is in the time interior enforcement energy acquisition also stores, at time t _kself up-link information x is sent according to time division multiple access way in T _k(k=1 ..., K), namely a kth user node sends the uplink signal moment a front k-1 user and carries out energy acquisition, subsequently complete send self up-link information after enter park mode immediately;

3. network time optimizes distribution:

1) a kth user node collecting energy is calculated k=1 ..., K;

In formula, P _iit is the transmitted power of i-th user node; D _{k, i}, α _{k, i}be respectively the Distance geometry path transmission loss factor of i-th user node to a kth user node; ζ _kfor the energy conversion efficiency of a kth user node, 0 < ζ _k< 1;

2) calculate a kth user node and gather power P _k: P _k=η _ke _k/ (t _kt), η in formula _kfor collecting energy utilance;

3) calculate each user node and can obtain uplink throughput C _k(t): C _k(t)=t _klog ₂(1+|h _{0, k}| ²p _k/ δ ²), h in formula _{0, k}for a kth user node is to the channel condition information of Integrated access point 0, δ ²for noise variance;

4) computing network current Uplink throughput

5) solve and upgrade peer distribution time t, computing network current Uplink throughput C (t); With uplink throughput maximization for criterion, C (t) value corresponding to more different distribution time t:

$\begin{array}{c}\underset{t}{\max }\left\{C\left(t\right)\right\}.\\ s.t.P_k\&le;P_0,\underset{k=0}{\overset{K}{\&Sigma;}}{t}_k=1,t_k\&GreaterEqual;0\end{array}$

In formula, { C (t) } represents the set that the C (t) that different distribution time t is corresponding is formed; represent choose C (t) corresponding to different distribution time t institute form gather in maximum C (t) value; S.t.P _k≤ P ₀represent the collecting energy constraints that should meet calculated in C (t) process, namely each node can collecting energy P _kintegrated access point 0 energy P should be less than ₀;

6) the peer distribution time t preserving corresponding maximum C (t) value is the time devided modulation value after optimizing;

4. the Internet Transmission stage

In same fading channel block, according to the time devided modulation value t after each node optimization, time division multiple access transmission means is adopted to carry out information transmission and energy acquisition; In subsequent channels fading channel block, if channel condition information changes, then optimization is re-started, repeated execution of steps 3 to network each peer distribution time; Otherwise, still by the time devided modulation value after current each node optimization, adopt time division multiple access transmission means to carry out information transmission and energy acquisition.

Object of the present invention can also be realized further by following technical measures:

Aforementioned throughput-maximized serial energy-collecting method, wherein user node possesses two radio frequency links, can complete the function of information transmission and energy acquisition in step 2 in downlink communication in different radio frequency link simultaneously.

Aforementioned throughput-maximized serial energy-collecting method, wherein ζ in step 3 _kbe less than 0.7.

Aforementioned throughput-maximized serial energy-collecting method, wherein optimizes allocated phase in step 3 network time, solves based on convex optimized algorithm to peer distribution time t.

Aforementioned throughput-maximized serial energy-collecting method, wherein optimize allocated phase in step 3 network time, based on heuristic value, peer distribution time t is solved, based on the standard particle group optimizing method in heuristic value to each peer distribution time t _kcarry out method for solving as follows:

(1) K+1 node is mapped to n particle;

(2) initialization particle rapidity v _kbe one group of random number, initialization fitness function value C _k(t)=0, each node time apportioning cost of initialization is one group of random number, itself and be T, and this time apportioning cost is mapped to particle initial position y _k(t);

(3) collecting energy and transmitted power is calculated;

A. a kth particle collecting energy is: k=1 ..., K; In formula, P _iit is the transmitted power of i-th user node; D _{k, i}, α _{k, i}be respectively the Distance geometry path transmission loss factor of i-th user node to a kth user node; ζ _kfor the energy conversion efficiency of a kth user node, 0 < ζ _k< 1;

B. a kth particle transmitted power is: P _k=η _ke _k/ (t _kt), η in formula _kfor collecting energy utilance;

(4) maximize criterion based on uplink throughput, calculate fitness function:

C _k(t)＝t _klog ₂(1+|h _0，k| ²P _k/δ ²)；

Based on fitness function computing network current Uplink throughput:

$C\left(t\right)=\underset{k=1}{\overset{K}{\&Sigma;}}{C}_k\left(t\right)$

(5) population is upgraded

If a. the individual extreme value of current particle is better than the individual extreme value of this particle of a moment, then upgrade the individual extreme value of current particle;

If b. the individual extreme value of current particle is better than a moment global extremum, then upgrade current global extremum;

C. the speed v of each particle is upgraded _kwith position y _k(t);

(6) repeated execution of steps (3)-(5) are until reach maximum iteration time;

(7) when reaching maximum iteration time, mapping global optimum's particle position is optimal network node time apportioning cost t, and corresponding C (t) is uplink throughput maximum.

Compared with prior art, the invention has the beneficial effects as follows: the uplink and downlink signal energy rationally gathering user node, the time devided modulation scheme of information transmission and energy acquisition between effective optimizing user node, improve network user node energy acquisition efficiency, reach the maximized object of network throughput.

Accompanying drawing explanation

Fig. 1 is the structure principle chart of wireless power of the present invention and communication network;

Fig. 2 is communication protocol sequential chart of the present invention;

Fig. 3 is time-optimized allocation flow figure of the present invention.

Embodiment

Below in conjunction with the drawings and specific embodiments, the invention will be further described.

Transmit while throughput-maximized serial energy-collecting method of the present invention can realize wireless communication system information and energy, be applicable to the cordless communication network with a node arbitrarily.As shown in Figure 1, in region, cordless communication network comprises 1 Integrated access point (node 0) and several user nodes (node 1 ~ K); The function of Integrated access point 0 is at downlink communication time t ₀energy is sent, at uplink communication time t in T ₁t ..., t _kin T, receiving data information (supposes in specific embodiment that each user node only has single radio frequency link, namely in downlink communication, only carries out energy acquisition.But when user node possesses two radio frequency links, in downlink communication, also can complete the function of information transmission and energy acquisition in different radio frequency link) simultaneously.User node k (k=1 ..., K) function be at downlink communication time t ₀collection Integrated access point being sent to signal energy is completed, at uplink communication time t in T ₁t ..., t _k-1the energy acquisition to front k-1 user node uplink signal is completed in T, and by its data information at uplink communication time t _ktransfer to Integrated access point 0 in T, immediately enter park mode.

The present invention proposes a kind of novel the particle group optimizing information transmission and the energy-collecting method that maximize criterion based on wireless uplink link throughput, institute's extracting method can the reasonable distribution node communication time, effectively improve wireless communication efficiency, improve network energy utilance, embodiment is as follows:

1. the netinit stage

As shown in Figure 1, intra-zone administration K+1 node, numbering 0 is Integrated access point, and numbering 1 ~ K is user node.Integrated access point is deployed in certain of network surrounding, has constant transmitted power P ₀, data message can be realized and receive; Each user node all can directly realize communicating with Integrated access point, has the function of energy acquisition, data processing and transmission.The total communication time of each node of network is T second, and initial phase is 0 ~ K peer distribution initialization time t at random ₀t, t ₁t ..., t _kt.Wherein, t _ifor time devided modulation weight (i=0,1 ..., K), t ₀+ t ₁+ ... + t _k=1, make t=[t ₀t ₁t _k].

2. network initial transmission phase

1) down link energy acquisition.Integrated access point 0 is at time t ₀with power P in T ₀continue to send down link signal x ₀, each user node is at time t ₀continuous reception down link signal x in T ₀, gather and store this signal energy.Now, a kth user node Received signal strength is y _k=h _{k, 0}x ₀+ z _k(k=1 ..., K).Wherein, h _{k, 0}for Integrated access point 0 is to the channel condition information of a kth user node, z _kfor additive white Gaussian noise, and suppose that noise power that each node receives can be ignored.

2) uplink energy collection and information transmission.Each user node, in uplink communication, all implements forward direction information transmission and backward energy acquisition by sequence number.When user node 1 is at time t ₁with power P in T ₁when sending up-link information to Integrated access point 0 (forward direction), user node 2 ..., K (backward) is at time t ₁energy acquisition is implemented in T; When user node 2 is at time t ₂with power P in T ₂when sending up-link information to Integrated access point 0 (forward direction), user node 3 ..., K (backward) is at time t ₂energy acquisition is implemented in T; By that analogy, when user node k is at time t _kwith power P in T _kwhen sending up-link information to Integrated access point 0 (forward direction), user node k+1 ..., K (backward) is at time t _kenergy acquisition is implemented in T.That is, a kth user node is in the time inside carry out energy acquisition and store, at time t _krespective up-link information x is sent according to time division multiple access way order in T _k(k=1 ..., K), after completing self up-link information of transmission, enter park mode immediately subsequently, sequential chart is as shown in Figure 2.

3. network time optimizes allocated phase, as shown in Figure 3, is time-optimized allocation flow figure of the present invention:

1) K+1 node is mapped to n particle.

2) initialization particle rapidity v _kbe one group of random number, initialization fitness function value C _kt ()=0, each node time apportioning cost of initialization is one group of random number (itself and for T), and this time apportioning cost is mapped to particle initial position y _k(t).

3) collecting energy and transmitted power is calculated.

1. a kth particle collecting energy is: k=1 ..., K.In formula, P _iit is the transmitted power of i-th user node; D _{k, i}, α _{k, i}be respectively the Distance geometry path transmission loss factor of i-th user node to a kth user node; ζ _kfor the energy conversion efficiency of a kth user node, 0 < ζ _k< 1.ζ _kconcrete value need be determined by real system circuit characteristic, is generally less than 0.7 with state-of-the art.

2. a kth particle transmitted power is: P _k=η _ke _k/ (t _kt), η in formula _kfor collecting energy utilance.

4) maximize criterion based on uplink throughput, calculate fitness function

C _k(t)＝t _klog ₂(1+|h _0，k| ²P _k/δ ²)

Based on fitness function computing network current Uplink throughput

$C\left(t\right)=\underset{k=1}{\overset{K}{\&Sigma;}}{C}_k\left(t\right)$

5) population is upgraded

If 1. the individual extreme value of current particle is better than the individual extreme value of this particle of a moment, then upgrade the individual extreme value of current particle.

If 2. the individual extreme value of current particle is better than a moment global extremum, then upgrade current global extremum.

3. the speed v of each particle is upgraded _kwith position y _k(t)

6) repeated execution of steps 3)-5) until reach maximum iteration time.

7) when reaching maximum iteration time, mapping global optimum's particle position is optimal network node time apportioning cost t, and corresponding C (t) is uplink throughput maximum.

4. the Internet Transmission stage

In same fading channel block, according to the time devided modulation value t after each node optimization, time division multiple access transmission means is adopted to carry out information transmission and energy acquisition.That is, Integrated access point 0 is at time t ₀with power P in T ₀continue to send down link signal x ₀, each user node is at time t ₀continuous reception down link signal x in T ₀, gather and store this signal energy; When user node 1 is at time t ₁with power P in T ₁when sending up-link information to Integrated access point 0 (forward direction), user node 2 ..., K (backward) is at time t ₁energy acquisition is implemented in T; When user node 2 is at time t ₂with power P in T ₂when sending up-link information to Integrated access point 0 (forward direction), user node 3 ..., K (backward) is at time t ₂energy acquisition is implemented in T; By that analogy, when user node k is at time t _kwith power P in T _kwhen sending up-link information to Integrated access point 0 (forward direction), user node k+1 ..., K (backward) is at time t _kenergy acquisition is implemented, as shown in Figure 2 in T.In subsequent channels fading channel block, if channel condition information changes, then optimization is re-started, repeated execution of steps 3 to network each peer distribution time.Otherwise, still by the time devided modulation value after current each node optimization, adopt time division multiple access transmission means to carry out information transmission and energy acquisition.

In addition to the implementation, the present invention can also have other execution modes, and all employings are equal to the technical scheme of replacement or equivalent transformation formation, all drop in the protection range of application claims.

Claims (5)

1. a throughput-maximized serial energy-collecting method, it is characterized in that, the method comprises the following steps:

1) netinit, disposes K+1 node; Numbering 0 is Integrated access point, and numbering 1 ~ K is user node; It is P that Integrated access point has firm power ₀watt, user node initial power is 0 watt; Integrated access point 0 and the total communication time of all K user node are T second, are 0 ~ K peer distribution initialization time t at random ₀t,t ₁t ..., t _kt; Wherein, t _ifor time devided modulation weight (i=0,1 ..., K), and t ₀+ t ₁+ ... + t _k=1, make t=[t ₀t ₁t _k];

2) network initial transmission

(1) down link energy acquisition: Integrated access point is at time t ₀with power P in T ₀continue to send down link signal x ₀, each user node is at time t ₀the down link signal x that in T, continuous reception Integrated access point sends ₀, gather and store this signal energy; A kth user node Received signal strength is y _k=h _{k, 0}x ₀+ z _k(k=1 ..., K), wherein, h _{k, 0}for Integrated access point 0 is to the channel condition information of a kth user node, z _kfor additive white Gaussian noise;

(2) uplink energy collection and information transmission: a kth user node is in the time interior enforcement energy acquisition also stores, at time t _kself up-link information xk (k=1 is sent according to time division multiple access way in T, K), namely a kth user node sends the uplink signal moment a front k-1 user and carries out energy acquisition, subsequently complete send self up-link information after enter park mode immediately;

3) network time optimizes distribution:

(1) a kth user node collecting energy E is calculated _k: k=1 ..., K;

In formula, P _iit is the transmitted power of i-th user node; D _k,i, α _k,ibe respectively the Distance geometry path transmission loss factor of i-th user node to a kth user node; ζ _kfor the energy conversion efficiency of a kth user node, 0< ζ _k<1;

(2) calculate a kth user node and gather power P _k: P _k=η _ke _k/ (t _kt), η in formula _kfor collecting energy utilance;

(3) calculate each user node and can obtain uplink throughput C _k(t): C _k(t)=t _klog ₂(1+|h _{0, k}| ²p _k/ δ ²), h in formula _{0, k}for a kth user node is to the channel condition information of Integrated access point 0, δ ²for noise variance;

(4) computing network current Uplink throughput

(5) solve and upgrade peer distribution time t, computing network current Uplink throughput C (t); With uplink throughput maximization for criterion, C (t) value corresponding to more different distribution time t:

$\underset{t}{max}\left\{C\left(t\right)\right\}.$

$s.t.P_k\&le;P_0,\underset{k=0}{\overset{K}{\&Sigma;}}{t}_k=1,t_k\&GreaterEqual;0$

In formula, { C (t) } represents the set that the C (t) that different distribution time t is corresponding is formed; represent choose C (t) corresponding to different distribution time t institute form gather in maximum C (t) value; S.t.P _k≤ P ₀represent the collecting energy constraints that should meet calculated in C (t) process, namely each node can collecting energy P _kintegrated access point 0 energy P should be less than ₀;

(6) the peer distribution time t preserving corresponding maximum C (t) value is the time devided modulation value after optimizing;

4) the Internet Transmission stage

In same fading channel block, according to the time devided modulation value t after each node optimization, time division multiple access transmission means is adopted to carry out information transmission and energy acquisition; In subsequent channels fading channel block, if channel condition information changes, then optimization is re-started, repeated execution of steps 3 to network each peer distribution time); Otherwise, still by the time devided modulation value after current each node optimization, adopt time division multiple access transmission means to carry out information transmission and energy acquisition.

2. serial energy-collecting method throughput-maximized as claimed in claim 1, it is characterized in that, described user node possesses two radio frequency links, in step 2) in downlink communication, the function of information transmission and energy acquisition can be completed in different radio frequency link simultaneously.

3. serial energy-collecting method throughput-maximized as claimed in claim 1, is characterized in that, described step 3) middle ζ _kbe less than 0.7.

4. serial energy-collecting method throughput-maximized as claimed in claim 1, is characterized in that, described step 3) network time optimization allocated phase, based on convex optimized algorithm, peer distribution time t is solved.

5. serial energy-collecting method throughput-maximized as claimed in claim 1, it is characterized in that, described step 3) network time optimization allocated phase, based on heuristic value, peer distribution time t is solved, based on the standard particle group optimizing method in heuristic value to each peer distribution time t _kcarry out method for solving as follows:

(1) K+1 node is mapped to n particle;

(2) initialization particle rapidity v _kbe one group of random number, initialization fitness function value C _k(t)=0, each node time apportioning cost of initialization is one group of random number, itself and be T, and this time apportioning cost is mapped to particle initial position y _k(t);

(3) collecting energy and transmitted power is calculated;

A. a kth particle collecting energy is: k=1 ..., K; In formula, P _iit is the transmitted power of i-th user node; D _k,i, α _k,ibe respectively the Distance geometry path transmission loss factor of i-th user node to a kth user node; ζ _kfor the energy conversion efficiency of a kth user node, 0< ζ _k<1;

B. a kth particle transmitted power is: P _k=η _ke _k/ (t _kt), η in formula _kfor collecting energy utilance;

(4) maximize criterion based on uplink throughput, calculate fitness function:

C _k(t)＝t _klog ₂(1+|h _0,k| ²P _k/δ ²)；

Based on fitness function computing network current Uplink throughput:

$C\left(t\right)=\underset{k=1}{\overset{K}{\&Sigma;}}{C}_k\left(t\right)$

(5) population is upgraded

If a. the individual extreme value of current particle is better than the individual extreme value of this particle of a moment, then upgrade the individual extreme value of current particle;

If b. the individual extreme value of current particle is better than a moment global extremum, then upgrade current global extremum;

C. the speed v of each particle is upgraded _kwith position y _k(t);

(6) repeated execution of steps (3)-(5) are until reach maximum iteration time;

(7) when reaching maximum iteration time, mapping global optimum's particle position is optimal network node time apportioning cost t, and corresponding C (t) is uplink throughput maximum.