Disclosure of Invention
In view of the above, the present invention provides a method for pricing load-based time-phased energy resources for reconfigurable intelligent surface-assisted wireless power communication networks, so as to solve at least some of the technical problems mentioned in the background art.
In order to achieve the above purpose, the present invention adopts the following technical scheme:
A time-sharing energy resource pricing method based on load is applied to a time-sharing energy resource pricing system, and comprises the following steps:
s1, constructing an energy collection model and a throughput model of the Internet of things equipment under a hybrid access point mode and an inherent energy node mode based on a time block model;
S2, enabling the Internet of things equipment to collect energy in the hybrid access point mode and/or the inherent energy node mode;
S3, dividing energy collection of the Internet of things equipment into a peak period and a non-peak period according to the energy supply demand of the Internet of things equipment, establishing a corresponding resource pricing model, and realizing time-division energy resource pricing through the resource pricing model.
Further, the energy supply node of the hybrid access point mode is a hybrid access point, and the energy supply node of the inherent energy node mode is an inherent energy node.
Further, the time block model divides the time block with the duration of T into an energy transmission duration and an information transmission duration.
Further, the step S1 specifically includes:
(1) In the energy transmission time length, under the hybrid access point mode, an energy collection model of the Internet of things equipment is built, wherein the energy collection model is specifically expressed as follows:
wherein E h,k represents energy collected by the Internet of things device k through the hybrid access point in the energy transmission time period, eta represents energy conversion efficiency, tau represents energy transmission time period, P h represents transmission power of the hybrid access point, w t,k represents a transmission beam forming vector of the hybrid access point, and Represents a set of plural numbers,Represents a complex matrix set with the size of Mx1, M represents the number of antennas equipped by the hybrid access point, h d,k represents a downlink channel between the hybrid access point and the Internet of things equipment k, andH r,k denotes a downlink channel between the reconfigurable intelligent surface and the internet of things device k, andN represents the number of reflecting units constituting the reconfigurable intelligent surface, (. Cndot.) H represents the conjugate transpose operation; Represents the conjugate transpose of H r,k, H d represents the downlink channel between the hybrid access point and the reconfigurable intelligent surface, and Θ 0 represents the energy reflective phase shift matrix of the reconfigurable smart surface, andΘ 0,n represents the phase reflection coefficient of the nth reflection unit of the reconfigurable intelligent surface during energy transmission, and θ 0,n ε [0,2π); Representing the complex exponential form of the phase reflection coefficient theta 0,n, Representing imaginary units, letV 0 denotes the reflection coefficient vector of the reconfigurable intelligent surface upon energy transfer, (·) T denotes the transpose operation;
(2) In the energy transmission time length, under the inherent energy node mode, an energy collection model of the Internet of things equipment is built, and the method specifically comprises the following steps:
E c,k represents energy collected by the internet of things device k through an inherent energy node in energy transmission time; the charging power of the internet of things equipment k in the inherent energy node mode is represented; Indicating the charging efficiency; The discharging power of the internet of things equipment k in the inherent energy node mode is represented; Indicating discharge efficiency;
(3) In the information transmission time length, under the mixed access point mode, a throughput model of the Internet of things equipment is built, and the method specifically comprises the following steps:
Wherein R h,k represents throughput of the Internet of things device k when energy transmission information is collected through the hybrid access point in the information transmission time period (1-tau) T represents the information transmission time period; G u,k represents an uplink channel between the Internet of things equipment k and the hybrid access point, and G r,k denotes an uplink channel between the internet of things device k and the reconfigurable intelligent surface, andG u denotes the uplink channel between the reconfigurable intelligent surface and the hybrid access point, andΘ 1 represents the information reflective phase shift matrix of the reconfigurable smart surface, andTheta 1,n represents the phase reflection coefficient of the nth reflection unit of the reconfigurable intelligent surface during information transmission, and theta 1,n E [0,2 pi ], letV 1 represents a reflection coefficient vector of the reconfigurable intelligent surface during information transmission; The method comprises the steps of decoding a beam forming vector when information transmitted by an Internet of things device K is decoded, wherein K represents the number of single-antenna Internet of things devices, P h,i represents the transmitting power of the information transmitted by the Internet of things device i in a hybrid access point mode, g u,i represents an uplink channel between the Internet of things device i and a hybrid access point, and g r,i represents an uplink channel between the Internet of things device i and a reconfigurable intelligent surface; Represents the conjugate transpose of g r,i, w r,i represents the transmit beamforming vector when decoding the information transmitted by the internet of things device i, σ 2 represents the additive white gaussian noise power;
(4) In the information transmission time length, under the inherent energy node mode, a throughput model of the Internet of things equipment is built, and the method specifically comprises the following steps:
wherein, R c,k represents throughput when the internet of things device k collects energy transmission information through the inherent energy node in the information transmission time; and the transmission power of the information transmitted by the internet of things device k in the inherent energy node mode is represented.
Further, in the step S2, when the internet of things device collects energy in the hybrid access point mode and the inherent energy node mode, energy is preferentially acquired in the hybrid access point mode, and when the hybrid access point load exceeds a preset value, energy is acquired in the inherent energy node mode.
Further, in the step S2, when the internet of things device collects energy in the intrinsic energy node mode, it is determined that one intrinsic energy node provides energy for the internet of things device according to the reputation value of the intrinsic energy node.
Further, the reputation value of the inherent energy node is expressed as:
Where S j represents the reputation value of the inherent energy node, N j represents the number of times the history of inherent energy node j was selected, and N max represents the maximum number of times the history of all inherent energy nodes was selected.
Further, the resource pricing model is expressed as:
wherein p represents energy resource pricing of the hybrid access point or the inherent energy node, B represents current load of the hybrid access point or the inherent energy node, and B is more than or equal to 0 and less than or equal to B max,Bmax, K is the number of single-antenna internet of things equipment, K is the kth internet of things equipment, alpha k is an energy demand indicating variable of the internet of things equipment K, alpha k =1 is that the internet of things equipment K needs energy supply, alpha k =0 is that the internet of things equipment K does not need energy supply, and p 0 is an energy resource initial price of a hybrid access point or an inherent energy node.
Further, the method further comprises the following steps:
S4, taking the Internet of things equipment as a leader, taking the energy supply node as a follower, and establishing a Stackelberg game model of energy transaction between the energy supply node and the Internet of things equipment, so as to maximize utility functions of the Internet of things equipment and the energy supply node.
Further, in the Stackelberg gaming model:
(1) The utility function maximization problem of the Internet of things equipment is expressed as:
s.t.C1:0≤B≤Bmax
C2:0<τ<1
C3:|v1|=1
Wherein U I represents a utility function of the Internet of things device, R represents rewards of unit throughput gain of the Internet of things device, p represents energy resource pricing of a hybrid access point or an inherent energy node, w r,k represents a beamforming vector when decoding information transmitted by the Internet of things device k, τ represents a time distribution ratio, τT represents an energy transmission duration, R k represents throughput when the Internet of things device k collects energy transmission information through the hybrid access point or the inherent energy node within the information transmission duration, E k represents energy collected by the Internet of things device k through the hybrid access point or the inherent energy node within the energy transmission duration, B represents current load of the hybrid access point or the inherent energy node, B max represents a load maximum, Θ 1 represents an information reflection phase shift matrix of a reconfigurable intelligent surface, and Theta 1,n represents the phase reflection coefficient of the nth reflection unit of the reconfigurable intelligent surface during information transmission, and theta 1,n E [0,2 pi ], letV 1 represents a reflection coefficient vector of the reconfigurable intelligent surface during information transmission, C1 represents a first constraint condition, C2 represents a second constraint condition, and C3 represents a third constraint condition;
(2) The energy supply node utility function maximization problem is expressed as:
s.t.C4:Pe≥0
C5:|v0|=1
Wherein U e represents the utility function of the energy supply node, w t,k represents the transmit beamforming vector of the hybrid access point, Θ 0 represents the energy reflective phase shift matrix of the reconfigurable smart surface; The method comprises the steps of representing a cost function of energy resources provided by an energy supply node in unit time, P e representing the transmitting power of a hybrid access point or the charging power of the Internet of things equipment k in an inherent energy node mode, wherein the charging power of the Internet of things equipment k in the inherent energy node mode is equal to the transmitting power of the inherent energy node, C4 representing a fourth constraint condition, and C5 representing a fifth constraint condition.
Compared with the prior art, the invention discloses a time-period energy resource pricing method based on load, which has the following beneficial effects:
According to the method, the energy resource price is properly adjusted in the peak time through the resource pricing model, the access of the Internet of things equipment is restrained, the energy resource price is properly reduced in the off-peak time, the Internet of things equipment is stimulated to access to obtain energy, and therefore the problem of pricing of the energy supply resources of the Internet of things equipment in a wireless power supply communication network scene can be effectively solved.
The method builds a Stackelberg game model of energy transaction between the energy supply node and the Internet of things equipment, gives the Internet of things equipment proper rewards in the information transmission stage of the Internet of things equipment so as to excite the Internet of things equipment to transmit information with larger transmitting power, thereby obtaining higher throughput, and finally enables the utility of both parties to be maximum through games between the energy supply node and the Internet of things equipment.
Additional features and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention.
The technical scheme of the invention is further described in detail through the drawings and the embodiments.
Detailed Description
The following description of the embodiments of the present invention will be made clearly and completely with reference to the accompanying drawings, in which it is apparent that the embodiments described are only some embodiments of the present invention, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
The embodiment of the invention discloses a load-based time-sharing energy resource pricing method, which is applied to a time-sharing energy resource pricing system, wherein the time-sharing energy resource pricing system is shown in figure 1 and comprises a hybrid access point provided with M antennas, a reconfigurable intelligent surface formed by N reflecting units, a RIS controller embedded into the reconfigurable intelligent surface, K single-antenna Internet of things devices, J inherent energy nodes and a central control unit embedded into the hybrid access point, wherein:
The hybrid access point is used for broadcasting energy to the Internet of things equipment and receiving information transmitted by the Internet of things equipment;
the inherent energy node provides energy for the equipment of the Internet of things in a leasing mode;
a Reconfigurable Intelligent Surface (RIS) for adjusting a wireless propagation environment between a hybrid access point and an Internet of things device;
a reconfigurable intelligent surface controller (RIS controller) for controlling the reconfigurable intelligent surface;
the internet of things equipment is used for energy receiving and information sending;
And the central control unit is used for adjusting the energy transaction prices and the energy acquisition modes in different time periods.
Based on the time-sharing energy resource pricing system, the load-based time-sharing energy resource pricing method provided by the invention is shown in figure 2, and comprises the following steps of
S1, constructing an energy collection model and a throughput model of the Internet of things equipment under a hybrid access point mode and an inherent energy node mode based on a time block model;
S2, the Internet of things equipment collects energy in a hybrid access point mode and/or an inherent energy node mode;
S3, dividing energy collection of the Internet of things equipment into a peak period and a non-peak period according to the energy supply demand of the Internet of things equipment, establishing a corresponding resource pricing model, and realizing time-interval energy resource pricing through the resource pricing model.
The respective steps described above are described in detail below.
In the step S1, an energy collection model and a throughput model of the internet of things device in two energy supply modes are established based on the time block model;
In the time block model, a time block with the duration of T is divided into two parts for energy transmission and information transmission respectively, and the energy transmission duration is defined as tau (1-tau) T, wherein tau represents the time distribution proportion and tau epsilon (0, 1);
The two energy supply modes comprise a hybrid access point mode and an inherent energy node mode, wherein the energy supply node of the hybrid access point mode is a hybrid access point, the energy supply node of the inherent energy node mode is an inherent energy node, the resource provided by the hybrid access point is called radio frequency resource, and the resource provided by the inherent energy node is called leased resource;
Based on the above, based on the time block model, respectively in a hybrid access point mode and an inherent energy node mode, an energy collection model and a throughput model of the internet of things device are constructed, which specifically comprises:
(1) In the energy transmission time length, under the hybrid access point mode, an energy collection model of the Internet of things equipment is built, wherein the energy collection model is specifically expressed as follows:
wherein E h,k represents energy collected by the Internet of things device k through the hybrid access point in the energy transmission time period, eta represents energy conversion efficiency, tau represents energy transmission time period, P h represents transmission power of the hybrid access point, w t,k represents a transmission beam forming vector of the hybrid access point, and Represents a set of plural numbers,Represents a complex matrix set with the size of Mx1, M represents the number of antennas equipped by the hybrid access point, h d,k represents a downlink channel between the hybrid access point and the Internet of things equipment k, andH r,k denotes a downlink channel between the reconfigurable intelligent surface and the internet of things device k, andN represents the number of reflecting units constituting the reconfigurable intelligent surface, (. Cndot.) H represents the conjugate transpose operation; Represents the conjugate transpose of H r,k, H d represents the downlink channel between the hybrid access point and the reconfigurable intelligent surface, and Θ 0 represents the energy reflective phase shift matrix of the reconfigurable smart surface, andΘ 0,n represents the phase reflection coefficient of the nth reflection unit of the reconfigurable intelligent surface during energy transmission, and θ 0,n ε [0,2π); Representing the complex exponential form of the phase reflection coefficient theta 0,n, Representing imaginary units, letV 0 denotes the reflection coefficient vector of the reconfigurable intelligent surface upon energy transfer, (·) T denotes the transpose operation;
(2) In the energy transmission time length, under the inherent energy node mode, an energy collection model of the Internet of things equipment is built, and the method specifically comprises the following steps:
E c,k represents energy collected by the internet of things device k through an inherent energy node in energy transmission time; the charging power of the internet of things equipment k in the inherent energy node mode is represented; Indicating the charging efficiency; The discharging power of the internet of things equipment k in the inherent energy node mode is represented; Indicating discharge efficiency;
(3) In the information transmission time length, under the mixed access point mode, a throughput model of the Internet of things equipment is built, and the method specifically comprises the following steps:
Wherein R h,k represents throughput of the Internet of things device k when energy transmission information is collected through the hybrid access point in the information transmission time period (1-tau) T represents the information transmission time period; G u,k represents an uplink channel between the Internet of things equipment k and the hybrid access point, and G r,k denotes an uplink channel between the internet of things device k and the reconfigurable intelligent surface, andG u denotes the uplink channel between the reconfigurable intelligent surface and the hybrid access point, andΘ 1 represents the information reflective phase shift matrix of the reconfigurable smart surface, andTheta 1,n represents the phase reflection coefficient of the nth reflection unit of the reconfigurable intelligent surface during information transmission, and theta 1,n E [0,2 pi ], letV 1 represents a reflection coefficient vector of the reconfigurable intelligent surface during information transmission; The method comprises the steps of decoding a beam forming vector when information transmitted by an Internet of things device K is decoded, wherein K represents the number of single-antenna Internet of things devices, P h,i represents the transmitting power of the information transmitted by the Internet of things device i in a hybrid access point mode, g u,i represents an uplink channel between the Internet of things device i and a hybrid access point, and g r,i represents an uplink channel between the Internet of things device i and a reconfigurable intelligent surface; Represents the conjugate transpose of g r,i, w r,i represents the transmit beamforming vector when decoding the information transmitted by the internet of things device i, σ 2 represents the additive white gaussian noise power;
(4) In the information transmission time length, under the inherent energy node mode, a throughput model of the Internet of things equipment is built, and the method specifically comprises the following steps:
wherein, R c,k represents throughput when the internet of things device k collects energy transmission information through the inherent energy node in the information transmission time; and the transmission power of the information transmitted by the internet of things device k in the inherent energy node mode is represented.
In the step S2, the internet of things device collects energy in the hybrid access point mode and/or the inherent energy node mode;
When the load of the hybrid access point exceeds a preset value (for example, 80%), the energy is acquired in the inherent energy node mode;
when the Internet of things equipment collects energy in an inherent energy node mode, determining one inherent energy node to provide energy for the Internet of things equipment according to the reputation value of the inherent energy node;
the reputation value of an inherent energy node is expressed as:
The method comprises the steps of S j, N j, N max and N max, wherein the S j represents the reputation value of an inherent energy node, the N j represents the historical selected times of the inherent energy node, the N max represents the maximum historical selected times of all inherent energy nodes, and the inherent energy node with the highest reputation value is selected to supply energy for the Internet of things equipment. At the same time, the internet of things equipment can only select one energy supply mode.
In the step S3, according to the energy supply requirement of the internet of things device, the energy collection of the internet of things device is divided into a peak period and a non-peak period, and a corresponding resource pricing model is established, the time-division energy resource pricing is realized through the resource pricing model, and the resource pricing model is expressed as:
wherein p represents energy resource pricing of the hybrid access point or the inherent energy node, B represents current load of the hybrid access point or the inherent energy node, and B is more than or equal to 0 and less than or equal to B max,Bmax, K is the number of single-antenna internet of things equipment, K is the kth internet of things equipment, alpha k is an energy demand indicating variable of the internet of things equipment K, alpha k =1 is that the internet of things equipment K needs energy supply, alpha k =0 is that the internet of things equipment K does not need energy supply, and p 0 is an energy resource initial price of a hybrid access point or an inherent energy node.
In another embodiment, the method further comprises:
S4, taking the Internet of things equipment as a leader, taking the energy supply node as a follower, establishing a Stackelberg game model of energy transaction between the energy supply node and the Internet of things equipment, and maximizing utility functions of the Internet of things equipment and the energy supply node, wherein the method comprises the following steps:
The energy supply node comprises a hybrid access point or an inherent energy node and is used for providing radio frequency resources or leasing resources for the Internet of things equipment, the energy supply node charges the Internet of things equipment, the energy collected by the Internet of things equipment is used for information transmission, the Internet of things equipment obtains rewards in an information transmission stage, and the Internet of things equipment is stimulated to transmit information with higher transmitting power to obtain higher throughput, so that the utility function of the Internet of things equipment is expressed as the difference between throughput benefit and energy expenditure and is expressed as:
UI=rRk-pEk
The energy supply node utility function is expressed as the difference between the energy return and the energy cost, expressed as:
Ue=pEk-τTC(Pe)
wherein, R k={Rh,k,Rc,k},Ek={Eh,k,Ec,k }, Representing the cost of providing energy resources per unit time by an energy supply node, whereinP h denotes the transmit power of the hybrid access point; the charging power of the Internet of things equipment k in the inherent energy node mode is represented The transmitting power of the node is equal to that of the inherent energy node, and a and b are normal numbers which can be obtained through actual data fitting;
the internet of things equipment decides whether to purchase energy or not, so the internet of things equipment is taken as a leader, an energy supply node is taken as a follower, and the following Stackelberg game model is established:
(1) The utility function maximization problem of the Internet of things equipment is expressed as:
s.t.C1:0≤B≤Bmax
C2:0<τ<1
C3:|v1|=1
Wherein U I represents a utility function of the Internet of things device, R represents rewards of unit throughput gain of the Internet of things device, p represents energy resource pricing of a hybrid access point or an inherent energy node, w r,k represents a beamforming vector when decoding information transmitted by the Internet of things device k, τ represents a time distribution ratio, τT represents an energy transmission duration, R k represents throughput when the Internet of things device k collects energy transmission information through the hybrid access point or the inherent energy node within the information transmission duration, E k represents energy collected by the Internet of things device k through the hybrid access point or the inherent energy node within the energy transmission duration, B represents current load of the hybrid access point or the inherent energy node, B max represents a load maximum, Θ 1 represents an information reflection phase shift matrix of a reconfigurable intelligent surface, and Theta 1,n represents the phase reflection coefficient of the nth reflection unit of the reconfigurable intelligent surface during information transmission, and theta 1,n E [0,2 pi ], letV 1 denotes a reflection coefficient vector of the reconfigurable intelligent surface in information transmission, C1 denotes a first constraint condition that the load of the energy supply node cannot exceed a maximum value B max, C2 denotes a second constraint condition that the distribution ratio of energy and information transmission time is between (0, 1), C3 denotes a third constraint condition that the phase reflection coefficient module of the reconfigurable intelligent surface in information transmission is 1;
(2) The energy supply node utility function maximization problem is expressed as:
s.t.C4:Pe≥0
C5:|v0|=1
Wherein U e represents the utility function of the energy supply node, w t,k represents the transmit beamforming vector of the hybrid access point, Θ 0 represents the energy reflective phase shift matrix of the reconfigurable smart surface; The method comprises the steps of representing a cost function of energy resources provided by an energy supply node in unit time, P e representing the transmitting power of a hybrid access point or the charging power of an Internet of things device k in an inherent energy node mode, wherein the charging power of the Internet of things device k in the inherent energy node mode is equal to the transmitting power of the inherent energy node, C4 representing a fourth constraint condition, representing that the transmitting power of the energy supply node is non-negative, C5 representing a fifth constraint condition, and representing that the phase reflection coefficient of a reconfigurable intelligent surface is 1 during energy transmission.
In summary, aiming at the problem that the wireless power supply communication network of the Internet of things is assisted by a reconfigurable intelligent surface, the invention aims at the problem of resource cost from the viewpoint of a service provider, provides a time-sharing energy resource pricing method based on load, which is used for properly adjusting the energy resource price in peak time and inhibiting the access of Internet of things equipment, properly reducing the energy resource price in off-peak time and exciting the access of the Internet of things equipment to acquire energy.
In the present specification, each embodiment is described in a progressive manner, and each embodiment is mainly described in a different point from other embodiments, and identical and similar parts between the embodiments are all enough to refer to each other. The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.