CN105490724A - Energy-carrying communication system bidirectional relay selection scheme based on maximization of minimum receiving signal-to-noise ratio - Google Patents

Abstract

The invention is applied to wireless energy-carrying relay communication, and discloses an energy-carrying communication system bidirectional relay selection scheme based on maximization of a minimum receiving signal-to-noise ratio, for improving the relay performance of a system. When the system runs, multiple relay nodes for selection by a user exist, an optimal relay is selected by use of a relay selection technology according to the scheme provided by the invention, and a base station and the user forward information by use of the selected relay. A wireless energy conversion apparatus is configured for the user, energy is collected from received signals, and the base station and the relays are provided with batteries. By use of the scheme provided by the invention, compared to random selection in the prior art, the system has the advantages of obviously improving the maximum value of a receiving signal-to-noise ratio of the system, improving the communication quality of the system, reducing the relay probability and the error rate and improving the system throughput.

Description

A kind of based on minimum received signal to noise ratio maximized portable communications system bi-directional relaying selection scheme

Technical field

The present invention relates to base station and user's two-way communication, particularly relate to a kind of based on the system of selection of minimum received signal to noise ratio maximized portable communications system bi-directional relaying.

Background technology

Relaying is the connection device of networked physics layer, and major function is by resending or forwarding data-signal, expands the distance of Internet Transmission.Simply generally, relaying is just used to amplifying signal in a network, and bi-directional relaying communication plan supports two one-way channels in same physical channel, achieve larger and speed, therefore bi-directional relaying technology obtains and studies widely, this technology can improve throughput of system, makes up the shortcoming that one-way junction system spectrum is low.At present, bidirectional relay system is WLAN (wireless local area network) (WLAN, WirelessLocalAreaNetwork), wireless sensor network (WSN, WirelessSensorNetworks) the efficient data communication in provides a kind of effective technological means, has obtained the great attention of academia and industrial circle.

Here adopt based on minimum received signal to noise ratio Standard-making relay selection scheme.Signal to noise ratio is a key technical indexes of tolerance communication system communication reliability.Increasing or improve signal to noise ratio is improve a main task of communication quality.In the transmission, by improving transmission means and increasing device ability realizes.Such as adopt optical cable, coaxial cable or satellite channel to reduce loss and noise.But after channel is selected, main by increasing device ability, in satellite communication, such as improve antenna gain and reduce receiver equivalent noise temperature.

The bi-directional relaying communication of power supply is a kind of new network schemer, wherein, the battery of Wireless Telecom Equipment can realize long-range supplementary technology (WPT) by microwave wireless power transmission device, to be decoded the signal (DF) received with certain energy by given power allocation factor after user's Received signal strength, remaining energy is kept in user, communicates for next time.The communication network (WPCN) of wireless power decreases the frequent trouble manually changing battery and charging, and has higher throughput, longer component life and lower network operation cost.In addition, WPCN can according to different environment and its transmitting power of service demand modeling, waveform, holding time, frequency size etc.Compare with traditional collection of energy, such as, WPCN utilizes regenerative resource because regenerative resource is random and time dependent mostly, cannot realize as required energy requirement to be supplied to equipment end.These obvious advantages that WPT compares traditional energy Supply Method make WPCN become a promising new model, but it is undeniable, WPCN also brings huge challenge, energy trasfer needs more complicated system, building efficient WPCN is a challenging problem in practice, on the one hand, due to power along with the energy that the decay of distance receives can be very low, this energy near-far interference can cause there is unjust phenomenon the user of different positions; On the other hand, in WPCN, the joint design of transmitting energy is necessary, first, the transmission of wireless energy and information is often correlated with, such as, before an equipment transmission data, WPT needs to gather in the crops enough energy, second, energy trasfer shares frequency spectrum and communication channel, and this may cause the common-channel interference to concurrent information transmission.For above-mentioned reasons, need new physical layer transmission technology and Network Protocol Design, to optimize the performance of WPCN.

Summary of the invention

The technical problem to be solved in the present invention is: a kind of base station with wireless charging and the relay selection scheme of user's two-way communication under minimum signal to noise ratio optimum, thus improves communication quality and the interruption performance of system, is applicable to radio communication.Operationally, there is multiple via node selected for user, relay selection technology selects an optimum relaying according to certain criterion to system, and base station and user utilize selected relay forwarding information.Wherein user is equipped with rechargeable battery, harvest energy from the signal received, and base station and relaying are equipped with battery.Utilize the present invention, can significantly reduce outage probability, the error rate, improve the throughput of system.

The present invention is based on minimum signal to noise ratio to be criterion to the maximum and to carry out the technical scheme that relay selection takes and be specially: base station and user's intercommunication system are made up of a base station, multiple relaying and a user, wherein relaying has an amplifier, base station and user be a decoder, and system is also equipped with a relay selection controller.In the present invention, base station and relaying are furnished with battery, and user does not have power supply supply, adopt wireless charging technology, harvest energy and charging from Received signal strength.

Be with minimum signal to noise ratio the selection that criterion carries out relaying to the maximum in the present invention, minimum signal to noise ratio refers in base station and user's two-way communication process, base station and user's received signal to noise ratio the poorest reach maximum.All nodes are operated in same frequency range all in a half duplex mode, directly do not contact between the base station considered and user, but by selected relay cooperative communication.In first time slot, user and base station are simultaneously to their signal of repeat transmitted, and in second time slot, first the signal received amplifies by via node, then forward to user and base station, and base station and user decode required information separately.

Different junction networks has a corresponding amplifier, Received signal strength is used for amplify with the Power Limitation meeting relaying, base station and user have a decoder, transmitting terminal energy emitter and signal projector have two cover antenna systems, each node of system comprises receiving element, transmitting element and data processing unit, base station and user's relaying, under the control of access control unit, are communicated by relay forwarding.

System of the present invention, based on the relay selection scheme in the most relative superiority or inferiority of minimum signal to noise ratio, comprises the following steps:

Step one, relay selection controller detects each trunk channel state information, carries out relay selection according to the present invention program's criterion;

Step 2, base station and user send information to selected relaying simultaneously;

Step 3, relaying amplifies to the received signal and is transmitted to base station and user;

Step 4, base station and user to the signal decoding received, wherein user's harvest energy, be used for decoded signal at given power factor next part energy, part energy preserves for sending signal next time;

Suppose that base station is B, user is that U, i relaying is respectively R ₁, R ₂... R _i.

Base station received signal expression formula is

$y_B=\sqrt{P_{R_i}}{h_i}^H{\mathrm{\α}}_i{y}_{R_i}+n_B$

Signal to noise ratio expression formula is

${\mathrm{\γ}}_B=\frac{P_{R_i}{P}_U\left|h_i{|}^2\right|g_i{|}^2}{(P_B{{\mathrm{\σ}}_B}^2+P_{R_i}{{\mathrm{\σ}}_{R_i}}^2)|h_i{|}^2+P_U|g_i{|}^2{{\mathrm{\σ}}_B}^2+{{\mathrm{\σ}}_B}^2{{\mathrm{\σ}}_{R_i}}^2}$

User's Received signal strength expression formula is

${\mathrm{\γ}}_U=\frac{(1-\mathrm{\ρ})P_{R_i}{P}_U\left|h_i{|}^2\right|g_i{|}^2}{P_B|h_i{|}^2{{\mathrm{\σ}}_U}^2+\[(1-\mathrm{\ρ})P_{R_i}{{\mathrm{\σ}}_{R_i}}^2+P_U{{\mathrm{\σ}}_U}^2\]|g_i{|}^2+{{\mathrm{\σ}}_U}^2{{\mathrm{\σ}}_{R_i}}^2}$

The relaying R selected under the maximum scheme of minimum signal to noise ratio _ishould meet

$i_{RSM}=\arg \underset{i}{\max }min\left\{\right|\left|h_i\right|{|}^2,\left|\right|g_i\left|{|}^2\right\}$

Here define system outage probability is P _out=P _r{ min (γ _u, γ _b) < γ _th, then more Iarge-scale system outage probability is less for corresponding minimum signal to noise ratio, can characterize minimum signal to noise ratio with system break probability.

Wherein, relaying amplification factor for the signal that relay reception arrives, h _ifor base station and in channel coefficients then, g _ifor user and in channel coefficients then, σ _b, σ _u, be respectively user, base station and relay reception signal noise variance, ρ is user side power allocation factor.

The channel information of the interruption selection control that the present invention can accomplish system detection system before a communication, thus find best relaying.Compared with Stochastic choice, the program significantly improves the minimum received signal to noise ratio of system, reduces the outage probability of system, and then improves point stage gain of system, reduces outage probability and the error rate, thus improves the throughput of system.

Accompanying drawing explanation

Fig. 1 is present system structural representation;

Fig. 2 is the inventive method flow chart;

The outage probability comparison diagram of Fig. 3 this programme and Stochastic choice.

Embodiment

Further describe below in conjunction with the drawings and specific embodiments.

Composition graphs 1, Fig. 2, the present invention is based on minimum signal to noise ratio to be criterion to the maximum and to carry out relay base station and user's intercommunication system is made up of a base station, multiple relaying and a user, wherein relaying has an amplifier, base station and user be a decoder, and system is also equipped with one and interrupts selection control.In the present invention, base station and relaying are furnished with battery, and user does not have power supply supply, adopt wireless charging technology, harvest energy and charging from Received signal strength.

Be with minimum signal to noise ratio the selection that criterion carries out relaying to the maximum in the present invention, minimum signal to noise ratio refers to and can allow in base station and user's two-way communication process, base station and user's received signal to noise ratio the poorest reach maximum.All nodes are operated in same frequency range all in a half duplex mode, directly do not contact between the base station considered and user, but by selected relay cooperative communication.In first time slot, user and base station are simultaneously to their signal of repeat transmitted, and in second time slot, first the signal received amplifies by via node, then forward to user and base station, and base station and user decode required information separately.

Different junction networks has a corresponding amplifier, Received signal strength is used for amplify with the Power Limitation meeting relaying, base station and user have a decoder, transmitting terminal energy emitter and signal projector have two cover antenna systems, each node of system comprises receiving element, transmitting element and data processing unit, base station and user's relaying, under the control of access control unit, are communicated by relay forwarding.

Composition graphs 2, system, based on the relay selection scheme in the most relative superiority or inferiority of minimum signal to noise ratio, comprises the following steps:

Step one, interrupts selection control and detects each trunk channel state information, carry out relay selection according to the present invention program's criterion;

Step 2, base station and user send information to selected relaying simultaneously;

Step 3, relaying amplifies to the received signal and is transmitted to base station and user;

Step 4, base station and user to the signal decoding received, wherein user's harvest energy, be used for decoded signal at given power factor next part energy, part energy preserves for sending signal next time;

Suppose that base station is B, user is that U, i relaying is respectively R ₁, R ₂... R _i.

Base station received signal expression formula is

$y_B=\sqrt{P_{R_i}}{h_i}^H{\mathrm{\&alpha;}}_i{y}_{R_i}+n_B$

Signal to noise ratio expression formula is

${\mathrm{\&gamma;}}_B=\frac{P_{R_i}{P}_U\left|h_i{|}^2\right|g_i{|}^2}{(P_B{{\mathrm{\&sigma;}}_B}^2+P_{R_i}{{\mathrm{\&sigma;}}_{R_i}}^2)|h_i{|}^2+P_U|g_i{|}^2{{\mathrm{\&sigma;}}_B}^2+{{\mathrm{\&sigma;}}_B}^2{{\mathrm{\&sigma;}}_{R_i}}^2}$

User's Received signal strength expression formula is

${\mathrm{\&gamma;}}_U=\frac{(1-\mathrm{\&rho;})P_{R_i}{P}_U\left|h_i{|}^2\right|g_i{|}^2}{P_B|h_i{|}^2{{\mathrm{\&sigma;}}_U}^2+\&lsqb;(1-\mathrm{\&rho;})P_{R_i}{{\mathrm{\&sigma;}}_{R_i}}^2+P_U{{\mathrm{\&sigma;}}_U}^2\&rsqb;|g_i{|}^2+{{\mathrm{\&sigma;}}_U}^2{{\mathrm{\&sigma;}}_{R_i}}^2}$

The relaying R selected under the maximum scheme of minimum signal to noise ratio _ishould meet

$i_{RSM}=\arg \underset{i}{\max }min\left\{\right|\left|h_i\right|{|}^2,\left|\right|g_i\left|{|}^2\right\}$

Here define system outage probability is P _out=P _r{ min (γ _u, γ _b) < γ _th, then more Iarge-scale system outage probability is less for corresponding minimum signal to noise ratio, can characterize minimum signal to noise ratio with system break probability.

Wherein, relaying amplification factor for the signal that relay reception arrives, h _ifor base station and in channel coefficients then, g _ifor user and in channel coefficients then, σ _b, σ _u, be respectively user, base station and relay reception signal noise variance, ρ is user side power allocation factor.

Further, the channel information of the interruption selection control that the present invention can accomplish system detection system before a communication, thus find best relaying.Compared with Stochastic choice, the program significantly improves the minimum received signal to noise ratio of system, reduces the outage probability of system, and then improves point stage gain of system, reduces outage probability and the error rate, thus improves the throughput of system.

Embodiment

As shown in Figure 1, based on present system by base station B, K relaying R ₁, R ₂... R _k, a user U forms.Described system is also equipped with one and interrupts selection control, is used for utilizing sounding channel information of the present invention, selects relaying R _i.Wherein different relayings has a corresponding amplifier, is used for Received signal strength to amplify with the Power Limitation meeting relaying; Base station and user have a decoder, are used for decoding desired signal from mixed signal.In the present invention, base station and relaying are furnished with battery, and user does not have power supply supply, adopt wireless charging technology, harvest energy and charging from Received signal strength.

As shown in Figure 2, be the selection that criterion carries out relaying to the maximum in the present invention with minimum signal to noise ratio, minimum signal to noise ratio refers to and can allow in base station and user's two-way communication process, base station and user's received signal to noise ratio the poorest reach maximum.After transmission starts, the interruption selection control sounding channel information of system, selects relaying, in first time slot, base station and user send information to selected relaying; In second time slot, first the signal received amplifies by via node, then forwards to user and base station, and base station and user decode required information separately.

Specifically be implemented as follows:

1. system break selection control selects relaying R according to the channel information detected _i, institute according to principle be $i_{RSM}=\arg \underset{i}{\max }min\left\{\right|\left|h_i\right|{|}^2,\left|\right|g_i\left|{|}^2\right\};$

2. base station and user are to retransmit, and then relaying amplification forwarding is to user and base station, suppose base station B in emulation, relaying R _i, the transmitting power of user U meets wherein $P_B=P_{R_i}={\mathrm{\&gamma;}}_0,$ Noise power meets ${\mathrm{\&sigma;}}_B={\mathrm{\&sigma;}}_{R_i}={\mathrm{\&sigma;}}_U=1.$

3. supposition channel is Nakagami is channel, and owing to can carry out the minimum signal to noise ratio of characterization system by outage probability, emulation draws outage probability and Stochastic choice Comparative result figure in the present invention.Demonstrate the present invention can accomplish to significantly reduce system break probability, improve minimum signal to noise ratio, improve the communication quality of system, reduce outage probability, the error rate, improve the throughput of system.

Claims (2)

1. one kind based on the system of selection of minimum received signal to noise ratio maximized portable communications system bi-directional relaying, base station and user's intercommunication system are made up of a base station, multiple relaying and a user, system is also equipped with one and interrupts selection control, base station and relaying are furnished with battery, user does not have power supply supply, adopt wireless charging technology, harvest energy from Received signal strength also charges;

Maximize as criterion carries out the selection of relaying with minimum signal to noise ratio, namely in base station and user's two-way communication process, base station and user's received signal to noise ratio the poorest reach maximum, base station, relaying and user are operated in same frequency range in a half duplex mode, do not contact directly between the base station considered and user, but by selected relay cooperative communication; In first time slot, user and base station are simultaneously to the respective signal of repeat transmitted, and in second time slot, first the signal received amplifies by via node, then forwards to user and base station, and base station and user decode required information separately;

Each relaying has an amplifier, is used for Received signal strength to amplify, and this amplifier has Power Limitation; Base station and user have a decoder, the energy emitter of base station and signal projector respectively have a set of antenna system, base station, relaying and user include receiving element, transmitting element and data processing unit, base station and user's relaying, under the control of access control unit, are communicated by relay forwarding.

2. method according to claim 1, specifically comprises the following steps:

Step one, interrupts selection control and detects each trunk channel state information, maximizes criterion carry out relay selection according to minimum signal to noise ratio;

Step 2, base station and user send information to selected relaying simultaneously;

Step 3, relaying amplifies to the received signal and is transmitted to base station and user;

Step 4, base station and user decode to the received signal, wherein user's harvest energy, and be used for decoded signal at given power factor next part energy, part energy preserves provides energy for sending signal next time;

Suppose that base station is B, user is that U, i relaying is respectively R ₁, R ₂... R _i;

Base station received signal expression formula is

$y_B=\sqrt{P_{R_i}}{h_i}^H{\mathrm{\&alpha;}}_i{y}_{R_i}+n_B$

Signal to noise ratio expression formula is

${\mathrm{\&gamma;}}_B=\frac{P_{R_i}{P}_U\left|h_i{|}^2\right|g_i{|}^2}{(P_B{{\mathrm{\&sigma;}}_B}^2+P_{R_i}{{\mathrm{\&sigma;}}_{R_i}}^2)|h_i{|}^2+P_U|g_i{|}^2{{\mathrm{\&sigma;}}_B}^2+{{\mathrm{\&sigma;}}_B}^2{{\mathrm{\&sigma;}}_{R_i}}^2}$

User's Received signal strength expression formula is

$y_U=\sqrt{-\mathrm{\&rho;}}\sqrt{P_{R_i}}{g_i}^H{\mathrm{\&alpha;}}_i{y}_{R_i}+n_U$

Signal to noise ratio is

${\mathrm{\&gamma;}}_U=\frac{(1-\mathrm{\&rho;})P_{R_i}{P}_U|h_i{|}^2|g_i{|}^2}{P_B|h_i{|}^2{{\mathrm{\&sigma;}}_U}^2+\&lsqb;(1-\mathrm{\&rho;})P_{R_i}{{\mathrm{\&sigma;}}_{R_i}}^2+P_U{{\mathrm{\&sigma;}}_U}^2\&rsqb;|g_i{|}^2+{{\mathrm{\&sigma;}}_U}^2{{\mathrm{\&sigma;}}_{R_i}}^2}$

The relaying R selected under the maximum scheme of minimum signal to noise ratio _ishould meet

$i_{RSM}=\arg \underset{i}{max}min\left\{\right|\left|h_i\right|{|}^2,\left|\right|g_i\left|{|}^2\right\}$

Here define system outage probability is P _out=P _r{ min (γ _u, γ _b) < γ _th, then more Iarge-scale system outage probability is less for corresponding minimum signal to noise ratio, characterizes minimum signal to noise ratio with system break probability;

Wherein, relaying amplification factor for the signal that relay reception arrives, h _ifor base station and in channel coefficients then, g _ifor user and in channel coefficients then, σ _b, σ _u, be respectively user, base station and relay reception signal noise variance, ρ is user side power allocation factor.