CN103997361B - The dual-mode selection technique method of two antenna wireless mobile relays - Google Patents

Abstract

The invention discloses a kind of dual-mode selection technique scheme of two antenna wireless mobile relay, it is characterised in that：Compare spectrum efficiency of the FD and HD patterns in double antenna relay system under AF agreements, by deriving the optimal power allocation under FD and HD patterns, obtain the SE expression formulas of maximum；According to theory analysis, a kind of new dual-mode selection strategy in two antenna AF relay systems is proposed, and verify by numerical result.The present invention proposes in two antenna AF relay systems a kind of new dual-mode selection strategy and verified by numerical result.

Description

The dual-mode selection technique method of two antenna wireless mobile relays

Technical field

The present invention relates to a kind of dual-mode selection technique scheme of two antenna wireless mobile relay.

Background technology

Relaying with multiple antennas can provide higher spectrum efficiency (SE) than single antenna relaying.The antenna number of mobile relay More, the spectrum efficiency that system can reach is higher.However, being limited by volume and cost, on the move after upper many of application Antenna is extremely difficult.In practice, a feasible scheme is exactly to configure two antennas in relay.

As hinge is connected between source node and destination node, relayed under full-duplex mode (FD) or semiduplex mode (HD) Complete reception and forwarding capability.When relaying is using FD patterns, signal is received at source node and is forwarded to destination node and is believed It number can share identical running time-frequency resource, but this can cause in antenna and is mutually disturbed between self-interference and antenna.The antenna of relay one Self-interference in antenna can be caused to occur when receiving and forward simultaneously；When relay antenna only completes individual event task (receive or forward) When, the signals leakiness of transmission antenna can reduce the performance of FD patterns into reception antenna (for example, mutually interference between antenna).Some grind The person of studying carefully begins one's study FD patterns, wherein all antennas relayed all simultaneously for receiving and forward to utilize day to greatest extent Line resource.However, for current self-interference technology for eliminating, mutual interference is real between eliminating inner antenna self-interference than eliminating antenna Now it is more difficult to.To avoid self-interference in antenna serious in FD patterns, a solution is to forbid any relay antenna while connecing Receive and forward signal.Two antenna FD herein are relayed, the scheme taken is that an antenna is used for receiving, and another antenna For forward signal, we are to waste the efficient running time-frequency resource utilization rate that some antennas resource has obtained FD patterns as cost.But It is that, under HD patterns and in the absence of self-interference problem, relaying all antennas can be used to receive and forward simultaneously.It is to account for High antenna efficiency is exchanged for more running time-frequency resources.Obviously, either FD patterns or HD patterns, can not all make full use of When-frequency-antenna resources.As far as we know up to the present, it is any double in two antenna wireless mobile relay cooperative systems It is still yet unresolved issue that work pattern, which can obtain higher spectrum efficiency,.

The content of the invention

The technical problem to be solved in the present invention is to overcome drawbacks described above there is provided a kind of duplex of two antenna wireless mobile relay Mode selection techniques scheme, the technical scheme theory analysis and numerical result all show that optimal dual-mode is provided depending on advantage Source, selection HD patterns mean that antenna resources are better than running time-frequency resource, and select FD patterns to mean that antenna resources are provided inferior to time-frequency Source.

To solve the above problems, the technical solution adopted in the present invention is：

A kind of dual-mode selection technique scheme of two antenna wireless mobile relay, it is characterised in that：

Compare spectrum efficiency of the FD and HD patterns in double antenna relay system under AF agreements, by deriving FD and HD patterns Under optimal power allocation, obtain maximum SE expression formulas；According to theory analysis, propose a kind of new in two antenna AF relay systems Dual-mode selection strategy, and verified by numerical result.

As a kind of technical scheme of optimization, system model is set up：Double antenna wireless mobile relay cooperative system, wherein source Node and destination node only have an antenna, are represented respectively by S and D, and relaying is equipped with two antennas, respectively with R1 and R2 tables Show.Under AF agreements, via node is simply to amplify the signal received and forward it to destination node, in FD patterns Under, R1 and R2 are respectively intended to receive and forward signal；And under HD patterns, R1 and R2 connect in first field in for a long time simultaneously The collection of letters number, in second field forward signal simultaneously interior for a long time；While FD relayings have higher time-frequency utilization rate in HD After with higher day line use ratio.

It is used as a kind of technical scheme of optimization, two antenna AF relay cooperative system maximum spectral efficiencies：Push away respectively first Then optimal power allocation under export FD and HD patterns proposes a two antenna AF to obtain the spectrum efficiency expression formula of maximum Relay dual-mode system of selection；

1), optimal power allocation under FD patterns：

In view of mutually being disturbed between antenna, the spectrum efficiency C under FD patterns_FDIt can be written as：

Understand that k=1 represents not leak into R1 power from R2 by formula (1), therefore the spectrum efficiency of FD patterns only depends on In γ₁₂And γ₂₁；When k level off to 0 when, such as transimission powers all R2 all leaks into R1, now FD relaying it is invalid；

Therefore, the optimization problem A1 of related maximization FD spectrum efficiency can be summarized as：

s.t.：1).P_s+P_r2≤P； (3)

2).P_s>=0, P_r2≥0 (4)

The general power of source node and relaying is P；Rain scavenging coefficient is introduced to characterize the spectrum efficiency of FD patterns.Due to finding log₂(1+ α) maximum is equivalent to find α maximum, and problem A1 translates into A2, and their solution is identical：

Constraints is still formula (3) and formula (4)；

2), the optimal power allocation of HD patterns：

Spectrum efficiency SE under HD patterns is expressed as C_HD,

Wherein, constant coefficient 1/2 is due to that under HD patterns, preceding half of frame length time is used to receive, rear half of frame length time For forwarding；Source node transmit power is 2Ps in preceding half of frame length time, and relay power is 2Pr in rear half of frame length time, this Sample just can guarantee that every frame power (Pr+Ps), meet the factor 2 and 4 in formula (19)；[2P_s(γ₁₁+γ₁₂)] and [2P_r2γ₂₂+ P_r1γ₂₁)] relaying and the received signal to noise ratio SNR of destination node are represented respectively.

Therefore, to be expressed as A3 as follows for related optimization problem：

s.t.：1).P_s+P_r1+P_r2≤P； (21)

2).P_s>=0, P_r1>=0, P_r2≥0 (22)

Wherein, the general power of source node and relaying is P；HD patterns are launched and received using all antennas of relaying. DefinitionIt can obtain

WhereinIt is because in the relay antenna assignment institute good to channel conditions that formula (23), which is set up, Some power rather than give each antenna distribution power；Therefore, defineAnd C_HDIt is [P_s(γ₁₁+γ₁₂)] and (P_r2γ₂₂+P_r1γ₂₁) monotonically increasing function, A3 can be converted into equivalence A4, i.e.,：

It is identical that constraints and formula (3) and (4) are provided；

Analyzed based on more than, the dual-mode system of selection in a double antenna AF relay cooperative system is proposed, with k γ₁₁ ≠γ₂₂WithExemplified by, due to compare the maximum spectral efficiency under FD and HD patterns with compared g (k) andIt is Valency, therefore the policy depiction proposed is as follows：

Dual-mode selection strategy：

The first step：For a given rain scavenging coefficient k, calculate g (k) andG (k) is constant,ForMinimum value；

Second step：IfHD patterns are selected, the 3rd step is otherwise gone to；

If g (k) is less thanMinimum value, because FD patterns and HD patterns are not intersected, for dual-mode Selection, it is not necessary that feedback γ₁₂With γ₂₁；

3rd step：For given γ₁₂And γ₂₁, calculateAnd be compared with g (k), if HD patterns are selected, FD patterns are otherwise selected.

By adopting the above-described technical solution, compared with prior art, the present invention considers mutually to do between antenna under FD patterns Disturb, spectrum efficiency of the FD and HD patterns in double antenna relay system is compared under AF agreements.By deriving under FD and HD patterns Optimal power allocation, obtain maximum SE expression formulas.According to theory analysis, it is proposed that a kind of new in two antenna AF relay systems Dual-mode selection strategy and verified by numerical result.

Embodiment

Embodiment：

A kind of dual-mode selection technique scheme of two antenna wireless mobile relay, it is characterised in that：

Compare spectrum efficiency of the FD and HD patterns in double antenna relay system under AF agreements, by deriving FD and HD patterns Under optimal power allocation, obtain maximum SE expression formulas；According to theory analysis, propose a kind of new in two antenna AF relay systems Dual-mode selection strategy, and verified by numerical result.

As a kind of technical scheme of optimization, system model is set up：Double antenna wireless mobile relay cooperative system, wherein source Node and destination node only have an antenna, are represented respectively by S and D, and relaying is equipped with two antennas, respectively with R1 and R2 tables Show.Under AF agreements, via node is simply to amplify the signal received and forward it to destination node, in FD patterns Under, R1 and R2 are respectively intended to receive and forward signal；And under HD patterns, R1 and R2 connect in first field in for a long time simultaneously The collection of letters number, in second field forward signal simultaneously interior for a long time；While FD relayings have higher time-frequency utilization rate in HD After with higher day line use ratio.

It is used as a kind of technical scheme of optimization, two antenna AF relay cooperative system maximum spectral efficiencies：Push away respectively first Then optimal power allocation under export FD and HD patterns proposes a two antenna AF to obtain the spectrum efficiency expression formula of maximum Relay dual-mode system of selection；

1), optimal power allocation under FD patterns：

In view of mutually being disturbed between antenna, the spectrum efficiency C under FD patterns_FDIt can be written as：

Understand that k=1 represents not leak into R1 power from R2 by formula (1), therefore the spectrum efficiency of FD patterns only depends on In γ₁₂And γ₂₁；When k level off to 0 when, such as transimission powers all R2 all leaks into R1, now FD relaying it is invalid；

Therefore, the optimization problem A1 of related maximization FD spectrum efficiency can be summarized as：

s.t.：1).P_s+P_r2≤P； (3)

2).P_s>=0, P_r2≥0 (4)

The general power of source node and relaying is P；Rain scavenging coefficient is introduced to characterize the spectrum efficiency of FD patterns.Due to finding log₂(1+ α) maximum is equivalent to find α maximum, and problem A1 translates into A2, and their solution is identical：

Constraints is still formula (3) and formula (4).

Lemma 1：Problem A2 is a strict convex optimization problem.

Prove：Defined function f (P_s, P_r2) as follows：

Due to [1/ (kP_Sγ₁₁P_r2γ₂₂)+1/(P_r2γ₂₂)+1/(kP_Sγ₁₁)] in (P_s, P_r2) what is opened is spatially one Individual strictly convex function, f (P_s, P_r2) in (P_s, P_r2) space in be a strictly convex function.On the other hand, it is easy to demonstrate,prove Bright P_s, P_r2And P_s+P_r2In (P_s, P_r2) what is opened is all spatially linear.Therefore, problem A2 is that a strict convex optimization is asked Topic.

In order to solve problem A2, we build A2 Lagrangian, are represented by J2：

Wherein λ is Lagrange multiplier, relevant with the constraints of formula (3).To J2 on P_sAnd P_r2Local derviation is asked to have：

Make respectivelyWithObtained equal to zero：

On the other hand, due to f (P_s, P_r2) (being provided by formula (6)) be P_sAnd P_r2Monotonically increasing function, optimization problem A2 Optimal solution must be fulfilled for following constraintss：

P_s+P_r2=P_. (10)

So, (10) are substituted into (9), Wo Menyou：

If k γ₁₁=γ₂₂, then the solution of (11) formula can be expressed as

If k γ₁₁≠γ₂₂, the solution of (11) formula is：

Wherein

In order to obtain k γ₁₁≠γ₂₂In the case of unique solution, we have following lemma 2.

Lemma 2：If k γ₁₁≠γ₂₂, problem A2 unique solution is

Wherein a, b, c are provided by (14) formula.

Prove：If k γ₁₁>γ₂₂, because (a-b)<0 and c>0, we can obtain P_S=[(a-b)/c]<0, this with about Beam condition P_S>=0 contradicts；If k γ₁₁<γ₂₂We have：

P can be obtained_S=[(a-b)/c]>P, this and constraints P_S≤ P is contradicted.Therefore, lemma 2 is set up.

Using equation (12)-(14), lemma 2 and constraints (10), we can obtain the optimal work(under FD patterns Rate is distributed：

2), the optimal power allocation of HD patterns：

Spectrum efficiency SE under HD patterns is expressed as C_HD,

Wherein, constant coefficient 1/2 is due to that under HD patterns, preceding half of frame length time is used to receive, rear half of frame length time For forwarding；Source node transmit power is 2Ps in preceding half of frame length time, and relay power is 2Pr in rear half of frame length time, this Sample just can guarantee that every frame power (Pr+Ps), meet the factor 2 and 4 in formula (19)；[2P_s(γ₁₁+γ₁₂)] and [2 (P_r2γ₂₂+ P_r1γ₂₁)] relaying and the received signal to noise ratio SNR of destination node are represented respectively.

Therefore, to be expressed as A3 as follows for related optimization problem：

s.t.：1).P_s+P_r1+P_r2≤P； (21)

2).P_s>=0, P_r1>=0, P_r2≥0 (22)

Wherein, the general power of source node and relaying is P；HD patterns are launched and received using all antennas of relaying. DefinitionIt can obtain

WhereinIt is because in the relay antenna assignment institute good to channel conditions that formula (23), which is set up, Some power rather than give each antenna distribution power；Therefore, defineAnd C_HDIt is [P_s(γ₁₁+γ₁₂)] (P_r2γ₂₂+P_r1γ₂₁) monotonically increasing function, A3 can be converted into equivalence A4, i.e.,：

It is identical that constraints and formula (3) and (4) are provided.

As lemma 1 is proved, it is also a Strict Convex optimization problem that we, which can equally obtain A4,.With A2 solution classes Seemingly, A4 optimal solution is：

Wherein

The spectrum efficiency of C.FD and HD patterns compares

Consider for fairness, compare identical γ₁₁And γ₂₂In the case of FD patterns and HD patterns maximum spectral efficiency. Formula (17) and (18) are substituted into (1), we can obtain the maximum spectral efficiency of FD patternsFor:

Wherein

Similar substitutes into formula (25)-(27) maximum spectral efficiency obtained in (19) under HD patterns For：

Wherein

From formula (28), it is easy to proveAs k increases monotonic increase.For given k,In γ₁₂ And γ₂₁Kept during change constant.Obviously, under FD patternsWithIt is the SE upper bound and lower bound respectively. As can be seen that the upper boundThanGreatly, andIt is γ₁₂And γ₂₁Monotonically increasing function.Therefore, faceAnd faceIn the presence of intersection.On the other hand, for lower boundDue toThereforeWithIn the absence of intersection.

Analyzed based on more than, the dual-mode system of selection in a double antenna AF relay cooperative system is proposed, with k γ₁₁ ≠γ₂₂WithExemplified by, due to compare the maximum spectral efficiency under FD and HD patterns with compared g (k) andIt is Valency, therefore the policy depiction proposed is as follows：

Dual-mode selection strategy：

The first step：For a given rain scavenging coefficient k, calculate g (k) andG (k) is constant,ForMinimum value；

Second step：IfHD patterns are selected, the 3rd step is otherwise gone to；

If g (k) is less thanMinimum value, because FD patterns and HD patterns are not intersected, for dual-mode Selection, it is not necessary that feedback γ₁₂With γ₂₁；

3rd step：For given γ₁₂And γ₂₁, calculateAnd be compared with g (k), ifHD patterns are selected, FD patterns are otherwise selected.

The present invention is not limited to above-mentioned preferred embodiment, and anyone should learn that what is made under the enlightenment of the present invention Structure change, it is every with it is of the invention have it is same or similar as technical scheme, belong to protection scope of the present invention.

Claims (1)

1. a kind of dual-mode system of selection of two antenna wireless mobile relay, it is characterised in that：

Compare the spectrum efficiency of full duplex FD and half-duplex HD patterns in double antenna relay system under AF agreements, by deriving FD With the optimal power allocation under HD patterns, the SE expression formulas of maximum are obtained；According to theory analysis, two antenna AF relay systems are proposed A kind of middle new dual-mode selection strategy, and verified by numerical result；

Set up system model：Double antenna wireless mobile relay cooperative system, wherein source node and destination node only have an antenna, Represented respectively by S and D, relaying is equipped with two antennas, is represented respectively with R1 and R2；Under AF agreements, via node is letter Signal that single amplification is received simultaneously forwards it to destination node, and under FD patterns, R1 and R2 are respectively intended to receive and forwarded Signal；And under HD patterns, R1 and R2 receive signal in first field in for a long time, in second field long-time simultaneously While forward signal；HD relayings have higher day line use ratio while FD relayings have higher time-frequency utilization rate；

Two antenna AF relay cooperative system maximum spectral efficiencies：Derive the optimal power point under FD and HD patterns respectively first It is equipped with and obtains maximum spectrum efficiency expression formula, then proposes a two antenna AF relaying dual-mode system of selection；

1), optimal power allocation under FD patterns：

In view of mutually being disturbed between antenna, the spectrum efficiency C under FD patterns_FDIt can be written as：

$C_{FD}={\log }_2(I-\frac{{\mathrm{\&kappa;P}}_s{\mathrm{\&gamma;}}_{11}{P}_{r2}{\mathrm{\&gamma;}}_{22}}{1+{\mathrm{\&kappa;P}}_s{\mathrm{\&gamma;}}_{11}+P_{r2}{\mathrm{\&gamma;}}_{22}}).---\left(1\right)$

Understand that k=1 represents not leak into R1 power from R2 by formula (1), therefore the spectrum efficiency of FD patterns is solely dependent upon γ₁₂ And γ₂₁；When k level off to 0 when, such as transimission powers all R2 all leaks into R1, now FD relaying it is invalid；

Therefore, the optimization problem A1 of related maximization FD spectrum efficiency can be summarized as：

A1：

s.t.：1).P_s+P_r2≤P； (3)

2).P_s>=0, P_r2≥0 (4)

S.t. represent to be limited to following condition；The general power of source node and relaying is P；Rain scavenging coefficient k is introduced to characterize FD patterns Spectrum efficiency；Due to finding log₂(1+ α) maximum is equivalent to find α maximum, and problem A1 translates into A2, and he Solution be identical：

A22

Constraints is still formula (3) and formula (4)；

2), the optimal power allocation of HD patterns：

Spectrum efficiency SE under HD patterns is expressed as C_HD,

$C_{HD}=\frac{1}{2}{\log }_2\&lsqb;1+\frac{4P_s({\mathrm{\&gamma;}}_{11}+{\mathrm{\&gamma;}}_{12})(P_{r2}{\mathrm{\&gamma;}}_{22}+P_{r1}{\mathrm{\&gamma;}}_{21})}{1+2P_s({\mathrm{\&gamma;}}_{11}+{\mathrm{\&gamma;}}_{12})+2(P_{r2}{\mathrm{\&gamma;}}_{22}+P_{r1}{\mathrm{\&gamma;}}_{21})}\&rsqb;---\left(19\right)$

Wherein, constant coefficient 1/2 is due to that under HD patterns, preceding half of frame length time is used to receive, and rear half of frame length time is used for Forwarding；Source node transmit power is 2Ps in preceding half of frame length time, and relay power is 2Pr in rear half of frame length time, so Every frame power (Pr+Ps) is can guarantee that, the factor 2 and 4 in formula (19) is met；[2P_s(γ₁₁+γ₁₂)] and [2 (P_r2γ₂₂+P_r1 γ₂₁)] relaying and the received signal to noise ratio SNR of destination node are represented respectively；

Therefore, to be expressed as A3 as follows for related optimization problem：

A3：

s.t.：1).P_s+p_r1+P_r2≤P； (21)

2).P_s>=0, P_r1>=0, P_r2≥0 (22)

Wherein, the general power of source node and relaying is P；HD patterns are launched and received using all antennas of relaying；DefinitionIt can obtain

$\max \{P_{r2}{\mathrm{\&gamma;}}_{22}+P_{r1}{\mathrm{\&gamma;}}_{21}\}=P_r{\widetilde{\mathrm{\&gamma;}}}_2,---\left(23\right)$

WhereinIt is because all work(of the antenna assignment good to channel conditions in relay that formula (23), which is set up, Rate rather than give each antenna distribution power；Therefore, defineAnd C_HDIt is [P_s(γ₁₁+γ₁₂)] and (P_r2 γ₂₂+P_r1γ₂₁) monotonically increasing function, A3 can be converted into equivalence A4, i.e.,：

A4：

It is identical that constraints and formula (3) and (4) are provided；

Analyzed based on more than, the dual-mode system of selection in a double antenna AF relay cooperative system is proposed, with k γ₁₁≠γ₂₂ WithExemplified by, due to compare the maximum spectral efficiency under FD and HD patterns with compared g (k) andBe it is of equal value, its In,

$g\left(\mathrm{\&kappa;}\right)\stackrel{\mathrm{\&Delta;}}{=}\frac{{\mathrm{\&kappa;P\&gamma;}}_{11}{\mathrm{\&gamma;}}_{22}\left(\frac{a+b}{c}\right)-{\mathrm{\&kappa;\&gamma;}}_{11}{\mathrm{\&gamma;}}_{22}{\left(\frac{a+b}{c}\right)}^2}{1+{\mathrm{P\&gamma;}}_{22}+\frac{1}{2}(a+b)}.---\left(29\right)$

$\tilde{g}({\mathrm{\&gamma;}}_{12},{\mathrm{\&gamma;}}_{21})\stackrel{\mathrm{\&Delta;}}{=}\frac{4P{\widetilde{\mathrm{\&gamma;}}}_1{\widetilde{\mathrm{\&gamma;}}}_2\left(\frac{\tilde{a}+\tilde{b}}{\tilde{c}}\right)-4{\widetilde{\mathrm{\&gamma;}}}_1{\widetilde{\mathrm{\&gamma;}}}_2\left(\frac{\tilde{a}+\tilde{b}}{\tilde{c}}\right)}{1+2P{\widetilde{\mathrm{\&gamma;}}}_2+\frac{1}{2}(\tilde{a}+\tilde{b})}.---\left(31\right)$

$\left\{\begin{array}{c}a=-2-2{\mathrm{P\&gamma;}}_{22};\\ b=\sqrt{4+4{\mathrm{P\&gamma;}}_{22}+4{\mathrm{\&kappa;\&gamma;}}_{11}P+4{\mathrm{\&kappa;\&gamma;}}_{11}{\mathrm{\&gamma;}}_{22}{P}^2};\\ c=2({\mathrm{\&kappa;\&gamma;}}_{11}-{\mathrm{\&gamma;}}_{21}).\end{array}\right.---\left(14\right)$

Therefore the policy depiction proposed is as follows：

Dual-mode selection strategy：

The first step：For a given rain scavenging coefficient k, calculate g (k) andG (k) is constant,For Minimum value；

Second step：IfHD patterns are selected, the 3rd step is otherwise gone to；

If g (k) is less thanMinimum value, because FD patterns and HD patterns are not intersected, for the choosing of dual-mode Select, it is not necessary that feedback γ₁₂With γ₂₁；

3rd step：For given γ₁₂And γ₂₁, calculateAnd be compared with g (k), if HD patterns are selected, FD patterns are otherwise selected.