CN103687023B

CN103687023B - Optimization Radio Resource method based on time delay differentiated service and proportionality rate constraint

Info

Publication number: CN103687023B
Application number: CN201310518212.4A
Authority: CN
Inventors: 余雪勇; 胡逸阳; 朱洪波
Original assignee: Nanjing Post and Telecommunication University
Current assignee: Nanjing huaruizhiguang Information Technology Research Institute Co., Ltd
Priority date: 2013-10-28
Filing date: 2013-10-28
Publication date: 2017-09-29
Anticipated expiration: 2033-10-28
Also published as: CN103687023A

Abstract

The invention discloses a kind of optimization Radio Resource method based on time delay differentiated service and proportionality rate constraint, delineation of activities is two types from physical layer by this method：Delay constraint type (Delay Constraint, DC) business and type (Best Effort, BE) business of doing one's best；Specifically, optimized allocation of resources is formulated for linear problem by the present invention, by introducing timesharing parameter, exponential mixed integer programming problem is converted into convex problem to solve；Result is asked again Lagrangian differential obtain bandwidth optimum performance response, checking the result is that it is no rationally, if unreasonable, decision-making is changed forward；If rationally, calculating other network allocation parameters；In a word instant invention overcomes the shortcoming that existing radio resource management method does not consider the fairness between type of service and user, and different kinds of business is met to service quality (quality of service, QoS diversity requirement), realize that message transmission rate is maximized, system overall data transmission rate is improved to greatest extent.

Description

Optimization Radio Resource method based on time delay differentiated service and proportionality rate constraint

Technical field

The present invention relates to Computer Wireless Communication technical field, time delay area is based in more particularly to a kind of heterogeneous wireless network The optimization Radio Resource method of separate service and proportionality rate constraint.

Background technology

As broadband wireless network being carried to the continuous of service quality (Quality of Service, QoS) demand in recent years Height, RRM (Radio Resource Management, RRM) becomes the emphasis of research and development.Existing industry Service type, such as the speech transmission service very sensitive to time delay are, it is necessary to ensure that it has certain handling capacity；And some business The of short duration time delay of (such as Email and file download service) tolerable, therefore they adapt to variable transmission rate.Orthogonal frequency Multiple access access (orthogonal frequency division multiple access, OFDMA) technology is divided to exist as one kind Emerging air interface solution in broadband network.Formulate the resource management plan of the heterogeneous wireless network comprising OFDMA technologies It slightly will be current and following study hotspot.

In current research field, Radio Resource generally includes transmit power and frequency bandwidth, can be dynamic using it Ground distribution, the time in processing broadband wireless fading channel or frequency selectivity problem.Optimal resource allocation plan in the past, and The key factors such as fairness between type of service and user are not considered, are inefficiently divided so as to result in rare Radio Resource Match somebody with somebody and utilize, in existing Resource Allocation Formula, based on bankruptcy strategy propose cooperative radio resource management (Joint RRM, JRRM it is) tactful, it is contemplated that the diversity of Radio Resource and seek system load and user on the basis of effective distributing radio resource/ The QoS demand of service, however, radio resource allocation mechanism (such as power and bandwidth) is using collaboration diversity technology and further full In the diversified qos requirement of sufficient different kinds of business, huge challenge is still suffered from.

As one kind common recognition, in terms of the overall data transmission rate and user fairness of balance system, the present invention always The constraint of user's proportionality transmission rate is used as equity criterion.Relative to traditional RRM strategies, the present invention is in the total speed of the system that meets Outside the user rate under the conditions of user rate constraint ratio is maximized and required, moreover it is possible to obtain higher message transmission rate and Fairness, and the problem of can solve above well.

The content of the invention

Present invention aims at providing, a kind of optimization based on time delay differentiated service and the constraint of proportionality rate fairness is wireless Resource allocation methods, this method is effectively reduced the switching times of wireless network and improves the service quality of network transmission (QoS), this method using business to Qos different demands come differentiated service type, introduce timesharing shared variable, multistep checking meter Result is calculated, the result after synthesis is applied in resource allocation, so as to improve the performance of radio resource allocation.

Delineation of activities is two kinds of fundamental types from physical layer by the present invention, and its two kinds of fundamental types are respectively：Delay constraint Type (Delay-Constraint, DC) business and type (Best-Effort, BE) business of doing one's best.Pure DC systems (only consider DC Business), refer to minimize system emission power, moreover it is possible to meet the master data transmission rate constraint of each user；Pure BE System (only considers BE business), refers to the total speed of system can be made to reach maximization, and obey total transmission power constraints.

The present invention is adopted the technical scheme that to solve its technical problem：The present invention proposes a kind of based on OFDMA technologies Heterogeneous network in optimized allocation of resources method, this method meet the total speed of system maximize and user's proportionality speed about The requirement of service quality under beam, this method considers different type of service and user fairness sex factor, and re-establishes one kind The network insertion model for allowing user multiple access to access, by delineation of activities is two types from physical layer：Delay constraint type (Delay-Constraint, DC) business and type (Best-Effort, BE) business of doing one's best.

Heterogeneous network will not only consider transmission rate constraint and type of service, also resource point when carrying out network selection Method of completing the square meets validity of the business to qos requirement, it is ensured that maximize power system capacity under the limitation of business minimum speed limit.By drawing Access customer proportionality rate constraint is used as equity criterion, and RRM planning problems are converted to linear programming problem, and index is complicated The mixed integer programming of property is converted into the maximized target of the transmission rate of BE business, while meeting different DC types business respectively Basic transmission rate, to greatest extent improve the total speed of system.The present invention has used for reference time sharing application, is ensureing BE type business Under the constraint of general power proportional fairness convex problem condition, using the solution and gradient projection method of dual problem to BE type business Comprehensive analysis is carried out with DC types business, it is ensured that DC type business has minimum transmission rate request, and BE types business is in no delay constraint Under the conditions of carried out data transmission in the way of doing one's best, but transfer rate is constrained by proportional fairness.

Method flow：

Step one：Assuming that in LTE-WLAN heterogeneous networks, there are M support different service types enlivens multimode terminal With the available wireless access technology of N kinds；In the lte networks, it is assumed that the wireless channel between base station and terminal is frequency selection Rayleigh fading channel, the channel of each subcarrier is narrower, therefore it is flat fading；r_inRepresent in each OFDM symbol time In interval, the transfer rate that user i is obtained based on subcarrier n, its value depends on channel gain h_inSubcarrier n is based on user i On the power P distributed_in；r_inIt is typically denoted as

Wherein, N₀It is the power spectral density of additive white Gaussian noise, Γ is a constant, referred to as SN space；

In the WLAN of 802.11 agreements, the present invention uses for reference the method for keeping out of the way information merged in MAC header, allows user with one The mode for planting TDMA accesses WLAN；All power transmissions are assumed, and user i is represented as r in j-th of WLAN_ij, equally For in above formula, r_ijIt can be represented as

Wherein, β represents the spectrum efficiency of provided subsystem, i.e., the validity of each subsystem；

Step 2：The difference required according to service delay, M MMT can be divided into two types：First kind DC types MMT, quantity is K, and the minimum transmission rate request of its business is(i=1,2 ..., K)；Second Type has (M-K) individual BE Type MMT, although without delay constraint, carried out data transmission in the way of doing one's best, but transmission rate is public by proportionality Flat constraint

DC type MMT and BE types MMT condition is expressed as：

r_K+1:r_k+2:...:r_M=γ_K+1:γ_K+2:...:γ_M；

Step 3：Under user's proportionality rate constraint, the total speed of maximum of all users is calculated：

Step 4：Define ρ_ijRepresent that (wherein 1≤j≤N refers to LTE network to user i, and N+1≤j≤N+L refers in network j J-th of WLAN) in time frame allocation of parameters.And introduce a variable s_ij, make s_ij=ρ_ijP_ij.Define α_ij=| h_ij|²/Γ_kN₀B_j, and by time frame allocation of parameters ρ_ij, can be by R_iIt is rewritten asConstraints It is rewritten as

Step 5：Using the Lagrangian of primal problem to s_ijPartial differential is sought, then result is updated to Caro need-storehouse In grace-Plutarch (Karush-Kuhn-Tucker, KKT) condition, you can obtain

Step 6：Using GRADIENT PROJECTION METHODS, the optimum performance response for obtaining bandwidth is And s is obtained by the conclusion in step 5_ij；

Step 7：Consider the continuous differential expression of the dual function of primal problem, optimization aim letter is updated using gradient projection method Several non-negative Lagrange multipliers, obtains suitable ρ_ijAnd s_ijAfterwards, the optimization solution of object function is obtained.

The system of the present invention includes：

First, system model

I. the present invention sets up LTE-WLAN heterogeneous networks (3GPP-LTE, hereinafter referred to as LTE) system model, and this model is basic Include the necessary factor such as network insertion and resource allocation.

Heterogeneous network system model is made up of 1 LTE network and L wlan network.Wherein, LTE base station and WLAN hot spot Overlay area can be overlapping, and assume all WLAN hot spots overlay area completely inside LTE overlay area.WLAN and LTE working frequency is separate, in the absence of inter-network interference.The channel of different WLAN distribution is not overlapping, also in the absence of interference. There are multiple multimode terminals in all signal coverage areas, can concurrently or separately access LTE network or wlan network.

Assuming that the Two dimensional Distribution model of a LTE-WLAN heterogeneous network is as shown in Figure 2.The base station of LTE network is located at coordinate Origin (0,0), three fan antennas, radius of society is 500m.Wherein, support IEEE 802.11a WLAN radius of society is 200m.In one LTE sector, two WLAN can partly overlap, and the two WLAN access points are located at coordinate (300,200) respectively The coverage of (300,200).The use for the sector being randomly dispersed in LTE is applied to this RRM per family.In emulation, this hair Bright hypothesis has 3 MMTS, and their random distributions are in the zone.1 DC (=12Mbps's) MMT and 2 (γ₂:γ₃=1: 1) MMT, multiple wireless networks can be accessed simultaneously.

II. in the lte networks, the total bandwidth of system is divided into F subcarrier, and comprising M in a RRM time frame Individual OFDM symbol interval.Therefore, system has N=FM resource block under total bandwidth, and each resource block corresponds to an OFDM A subcarrier in mark space.r_0inRepresent the transfer rate that user i is obtained based on resource block n, wherein n=(a-1) F+b Represent the resource block (1≤a≤M, 1≤b≤F, 1≤n≤N) of b-th of subcarrier in a-th of OFDM symbol interval.Assuming that all The fading coefficients of user keep constant in a time frame, variable in different time frames.Central controller in base station All channel informations can be predicted, the channel information that each terminal collection is estimated is sent to base station by feedback channel, or Channel estimation is carried out by the up-link in time division duplex (TDD) system.Subcarrier is substituted into using the feedback information being recovered to In power distribution method, central controller is allowed to distribute different subcarriers for user, and determined often according to transient channel input Power/the bit quantity sent on individual subcarrier.If the transmission power of base station is P_T。

III. present invention assumes that the wireless channel between base station and terminal is the rayleigh fading channel of frequency selection.However, The channel of each subcarrier is narrower, therefore it is flat fading.r_inRepresent in each OFDM symbol time interval, user i The transfer rate obtained based on subcarrier n, its value depends on channel gain h_inWith user i based on the work(distributed on subcarrier n Rate P_in.Generally, r_inIt is typically denoted as

Here, N₀It is the power spectral density of additive white Gaussian noise, Γ is a constant, referred to as SN space.

In the WLAN of 802.11 agreements, media access control (MAC) agreement that the present invention considers is used based on reservation Modified distributed coordination function.By merging the information of keeping out of the way in MAC header, user can collision free conflict completely.Therefore, The present invention can simply allow user to access WLAN in the way of a kind of TDMA, and each user exclusively enjoys in the time frame distributed All bandwidth.All power transmissions are assumed, and user i is represented as r in j, ground WLAN_ij, in upper, r_ijCan To be represented as

In (1) and (2), β is that, the invention provides the validity of each subsystem, it represents provided subsystem Spectrum efficiency.

2nd, mathematical modeling

I. the present invention is modeled again first, it is assumed that in LTE-WLAN heterogeneous networks, there are M support different service types Enliven multimode terminal (Multi-Mode Terminal, MMT) and the available wireless access technology of N kinds (RAT).Each MMT can To obtain the Radio Resource of heterogeneous networks by way of multiple access.Different according to the requirement of service delay, M MMT can be by Divide into two types：First kind DC type MMT, quantity is K, and the minimum transmission rate request of its business is(i=1, 2,...,K)；Second Type has (M-K) individual BE types MMT, without delay constraint, is carried out data transmission in the way of doing one's best, But transfer rate is constrained by proportional fairness.

DC and BE condition is expressed as：

r_K+1:r_k+2:...:r_M=γ_K+1:γ_K+2:...:γ_M(4)

HereIt is DC types MMT minimum transmission rate constraint, is the mathematical expectation of DC type MMT minimum-rates.γ_i (i=K+1, K+2 ..., M) is BE types MMT proportionality fairness parameter.

In II.LTE-WLAN heterogeneous networks, under user's proportionality rate constraint, the total speed of maximum of all users is solved It is as follows：

Wherein, j represents network index (i.e. j=0 is that LTE and network j (1≤j≤L) is j-th of wlan network).α_ijRepresent Network selection parameters of the user i in network j.f_ijFor resource allocation parameters of the user i in LTE resource block n, t_ijFor user i In the time frame allocation of parameters of j-th of wlan network.

Wherein, formula (5b) ensures that each user can only have access single network in each RRM time frames, and (5c) ensures Resource block in the lte networks can only be by single user occupancy.R_iFor user i data rate, (5g) represents different proportion User data transmission rate limit.{γ_k+1,γ_k+2,...,γ_MIt is to ensure fair preset of resource allocation between different user Value.

III. above-mentioned (5b) and (5c) integer constraints are relaxed.MMT can pass through multiple RATs parallel transmissions numbers According to network be referred to as multiple wireless access (multi-radio access, MRA) system, it can accommodate LTE and 802.11WLAN Subsystem.If α_ij=1, the single network selection constraint of expression can relax can be while access multiple networks for user.Secondly, this hair It is bright to allow multiple users to share a resource element in LTE, multiple users is shared in the way of FDMA in LTE network Same resource block.Formula (5e) is expressed as

Wherein 0≤f_ij≤ 1 represents the part that user i is distributed by resource block n.

Finally, abbreviation (5) is as follows：

3rd, the application of timesharing technology of sharing

I. the present invention is approximately carry out time frame distribution in TDMA modes, i.e. OFDM- the resource element in LTE TDMA.In order to reduce the complexity of the problem, the present invention is converted into a convex letter by introducing a timesharing shared variable Number optimization problem.

Define ρ_ijRepresent user i in network j (whereinRefer to LTE network, N+1≤j≤N+L refers to j-th WLAN the time frame allocation of parameters in).Introduce a variable s_ij, make s_ij=ρ_ijP_ij.Obviously, s_ijUser i is assigned to exist J-th of subcarrier (1≤j≤N) or the power of j-th of WLAN (N+1≤j≤N+L).P_ijSubcarrier or WLAN access points by with The power that family i takes.

For the sake of simplicity, defining α_ij=| h_ij|²/Γ_kN₀B_j, represent efficient channel noise ratios of the user i in subcarrier n (CNR).Therefore, R_iIt can be expressed as

II. by time frame allocation of parameters ρ_ij, (6) are converted to following form：

Here P_TIt is the total transmission power from LTE base station and WLAN access points.Wherein, (8a) is f (ρ_ij,s_ij)=β_jB_jρ_ijlog₂(1+s_ijC/ρ_ij) summation, wherein C is normal number.

By assessing f (ρ_ij,s_ij) in ρ_ij,s_ijHessian matrixes, the present invention can prove f (ρ i_j,s_ij) it is recessed letter Number, because the inequality constraints equation of (8b) is convex equation, and it is all affine function that (8c)-(8f) is all, this optimization The feasible zone of scheme is convex function collection.Thus the present invention can be converted to equation (8) a convex optimization problem, and multinomial Unique optimal solution is obtained in the formula time.

4th, many wireless access

I. for the optimal solution of capacity greatest problem, formula (9) gives Lagrangian, wherein λ_j,μ,v_iAnd ω_iIt is The Lagrange multiplier of non-negative.By introducing on λ_j,μ,v_iAnd ω_iDerivative, by KKT conditions, the present invention can obtain two kinds The general differential equation of type of service：

Inequality (10), (11) are ρ_ijAnd s_ijNecessary condition and adequate condition.

As 1≤i≤K

As K+1≤i≤M, have

By inequality (10), (11) have：

II. { ρ is set_ijIt is a given subcarrier distribution scheme.By Lagrangian (9) to s_ijDifferentiate, then knot Fruit is updated to that KKT conditions (11) are inner, and the present invention can be obtained

Wherein i=1,2 ... K, K+1 ..., M and j=1,2 ..., L+N.Here [z]⁺=max { z, 0 }.Formula (17) is represented Optimal power allocation obeys standard water flood, in addition, allocated power only relies upon ρ_ijTime frame.In order to obtain ρ_ijWith s_ijOptimal solution, by equation (9), the present invention can obtain its dual problem and be：

D(λ_j,μ,v_i,ω_i)=max L (s_ij,ρ_ij,λ_j,μ,v_i,ω_i) (18)

III. basis is found to convex problem analysis, and primal problem (9) and its dual problem (18) have strong duality.Cause This, the present invention can obtain the optimal solution of (9) by solving (18).If iteration step length selection is appropriate, gradient projection is utilized Method is come to move closer to optimal solution be feasible.So, the present invention is adopted to be responded to obtain the optimum performance of bandwidth with the following method:

Here δ is ρ_ijConstant iteration step length, as long as step-length δ selections are appropriate, ρ_ijIt can converge to optimal value.Obtaining ρ_ijAfterwards, s_ijIt can be tried to achieve by (17).The optimal solution of Lagrange multiplier value is obtained, the present invention considers continuously differentiable antithesis Equation.Using gradient projection method, the power distribution for the non-negative multiplier tried to achieve is as follows

WhereinIt is the constant vector of a step-length.According to alternative manner, the present invention solves heterogeneous network The optimization problem of multiple access in network, improves the total capacity of system to greatest extent.

5th, the Radio Resource optimum management method based on time delay differentiated service and proportionality rate constraint

Include for multimode terminal (MMT) i as follows：

Step 1：Initialization：δ is set,μ⁰,WithInitial value,

Iterations initial value k=0 is set；

Step 2：Calculated with gradient projection method

Step 3：Obtain

Step 4：The ρ that if alternative manners are obtained_ijAnd s_ijMeet the condition of convergence or reach maximum iteration；

then

UtilizeWithTo calculate RAT (s) transmission message transmission rate；

else

UtilizeWithTo updateand

k←k+1,goto step 2)；

end if

Include for the access point in RAT j：

Step 1：UtilizeCalculate

Step 2：After renewalAll MMTs are broadcast to,

Step 3：k←k+1,goto step 1)

The present invention seeks to solve the problems, such as the optimal solution of (7), dual equation D (λ using based on projection gradient method_j,μ, v_i,ω_i) it is convex, the method for gradient type can go to update D (λ according to the appropriate direction of search_j,μ,v_i,ω_i) and obtain D simultaneously (λ_j,μ,v_i,ω_i) minimum value, so that it is guaranteed that it converges to optimal solution.In general, D (λ_j,μ,v_i,ω_i) can be not micro-, I.e. its gradient is not present.

Beneficial effect：

1st, the present invention realizes the message transmission rate of BE type business under the conditions of the basic transmission rate of DC type business is met Maximize, so that the total handling capacity of system reaches maximum.

2nd, the present invention is according to optimal allocation strategy, it is easy to draw under resource proportionality fair allocat, multiple BE types Business is capable of the Radio Resources such as the acquisition bandwidth and power of justice, so as to each reach corresponding message transmission rate.

Brief description of the drawings

Fig. 1 is present system illustraton of model.

Fig. 2 is the simulation model figure of LTE-WLAN networks of the present invention.

Fig. 3 is flow chart of the method for the present invention.

Embodiment

The invention is described in further detail below in conjunction with Figure of description.

As shown in figure 3, a kind of Radio Resource based on time delay differentiated service and proportionality rate constraint of present invention offer is excellent Change management method, this method comprises the following steps：

Wherein, N₀It is the power spectral density of additive white Gaussian noise, Γ is a constant, referred to as SN space； In the WLAN of 802.11 agreements, user accesses WLAN in the way of TDMA；All power transmissions are assumed, and user i is in jth R is represented as in individual WLAN_ij, similarly in above formula, r_ijIt is represented as

DC type MMT and BE types MMT condition is expressed as：

r_K+1:r_k+2:...:r_M=γ_K+1:γ_K+2:...:γ_M；

Step 4：Define ρ_ijRepresent that (wherein 1≤j≤N refers to LTE network to user i, and N+1≤j≤N+L refers in network j J-th of WLAN) in time frame allocation of parameters, and introduce a variable s_ij, make s_ij=ρ i_jP_ij, define α_ij=| h_ij|²/ Γ_kN₀B_j, and by time frame allocation of parameters ρ_ij, can be by R_iIt is rewritten asConstrain bar Part is rewritten as

The system of the present invention includes：

First, system model

I. the research of the RRM mechanism under heterogeneous network based on OFDMA technologies, the present invention sets up LTE- WLAN heterogeneous networks (3GPP-LTE, hereinafter referred to as LTE) system model, this model includes network insertion and resource allocation etc. substantially Necessary factor.

Heterogeneous network system model such as Fig. 1, is made up of 1 LTE network and L wlan network.Wherein, LTE base station and WLAN The overlay area of focus can be overlapping, and assumes the overlay area of all WLAN hot spots completely inside LTE overlay area.WLAN Working frequency with LTE is separate, in the absence of inter-network interference.The channel of different WLAN distribution is not overlapping, also in the absence of dry Disturb.There are multiple multimode terminals in all signal coverage areas, can concurrently or separately access LTE network or wlan network.

2nd, mathematical modeling

DC and BE condition is expressed as：

r_K+1:r_k+2:...:r_M=γ_K+1:γ_K+2:...:γ_M (4)

III. above-mentioned (5b) and (5c) integer constraints are relaxed.MMT can pass through multiple RATs parallel transmissions numbers According to network be referred to as multiple wireless access (multi-radio access, MRA) system, it can accommodate LTE and 802.11 WLAN Subsystem.If α_ij=1, the single network selection constraint of expression can relax can be while access multiple networks for user.Secondly, this hair It is bright to allow multiple users to share a resource element in LTE, multiple users is shared in the way of FDMA in LTE network Same resource block.Formula (5e) is expressed as

Finally, abbreviation (5) is as follows：

3rd, the application of timesharing technology of sharing

Define ρ_ijRepresent that (wherein 1≤j≤N refers to LTE network to user i, and N+1≤j≤N+L refers to j-th in network j WLAN the time frame allocation of parameters in).Introduce a variable s_ij, make s_ij=ρ_ijP_ij.Obviously, s_ijUser i is assigned to exist J-th of subcarrier (1≤j≤N) or the power of j-th of WLAN (N+1≤j≤N+L).P_ijSubcarrier or WLAN access points by with The power that family i takes.

By assessing f (ρ_ij,s_ij) in ρ_ij,s_ijHessian matrixes, the present invention can prove f (ρ_ij,s_ij) it is recessed letter Number.Because the inequality constraints equation of (8b) is convex equation, and it is all affine function that (8c)-(8f) is all, this optimization The feasible zone of scheme is convex function collection.Thus the present invention can be converted to equation (8) a convex optimization problem, and multinomial Unique optimal solution is obtained in the formula time.

4th, many wireless access

As 1≤i≤K

As K+1≤i≤M, have

By inequality (10), (11) have：

D(λ_j,μ,v_i,ω_i)=maxL (s_ij,ρ_ij,λ_j,μ,v_i,ω_i) (18)

Include for multimode terminal (MMT) i as follows：

Step 1：Initialization：δ is set,μ⁰,WithInitial value,

Iterations initial value k=0 is set；

Step 2：Calculated with gradient projection method

Step 3：Obtain

then

UtilizeWithTo calculate RAT (s) transmission message transmission rate；

else

UtilizeWithTo updateand

k←k+1,goto step 2)；

end if

Include for the access point in RAT j as follows：

Step 1：UtilizeCalculate

Step 2：After renewalAll MMTs are broadcast to,

Step 3：k←k+1,goto step 1)

As shown in Figures 1 and 2, the multiple access optimal condition under being distinguished based on type of service, the present invention utilizes projection Seek to solve the problems, such as the optimal solution of (7) based on gradient method, because dual equation D (λ_j,μ,v_i,ω_i) it is convex, gradient The method of formula can go to update D (λ according to the appropriate direction of search_j,μ,v_i,ω_i) and obtain D (λ simultaneously_j,μ,v_i,ω_i) most Small value, so that it is guaranteed that it converges to optimal solution.In general, D (λ_j,μ,v_i,ω_i) can be not micro-, i.e., its gradient is not deposited .

The present invention in multiple access radio resource allocation problem in order to maximize overall system capacity, it is also proposed that one point Cloth decision mode, its complexity is the function that iteration step length and initial value are together decided on.Although (7) can be excellent by centralization Change method solves convergency value, and can ensure that no loss of signal, but the present invention or first choice use distributed optimization method, so that Each MMT does decision-making under the operation of correct synchronized update, applied to the wireless connection between each terminal and different access networks In.

Claims

1. a kind of optimization radio resource management method based on time delay differentiated service and proportionality rate constraint, it is characterised in that Methods described comprises the following steps：

Step one：Assuming that in LTE-WLAN heterogeneous networks, there are M support different service types enlivens multimode terminal and N Plant available wireless access technology；In the lte networks, it is assumed that the wireless channel between base station and terminal is the Rayleigh of frequency selection Fading channel, the channel of each subcarrier is narrower, therefore it is flat fading；r_inRepresent in each OFDM symbol time interval Interior, the transfer rate that user i is obtained based on subcarrier n, its value depends on channel gain h_inInstitute on subcarrier n is based on user i The power P of distribution_in；r_inIt is typically denoted as：

<mrow> <msub> <mi>r</mi> <mrow> <mi>i</mi> <mi>n</mi> </mrow> </msub> <mo>=</mo> <msub> <mi>&beta;</mi> <mn>0</mn> </msub> <msub> <mi>B</mi> <mn>0</mn> </msub> <msub> <mi>log</mi> <mn>2</mn> </msub> <mrow> <mo>(</mo> <mn>1</mn> <mo>+</mo> <mfrac> <mrow> <msub> <mi>P</mi> <mrow> <mi>i</mi> <mi>n</mi> </mrow> </msub> <msup> <mrow> <mo>|</mo> <msub> <mi>h</mi> <mrow> <mi>i</mi> <mi>n</mi> </mrow> </msub> <mo>|</mo> </mrow> <mn>2</mn> </msup> </mrow> <mrow> <msub> <mi>&Gamma;N</mi> <mn>0</mn> </msub> <msub> <mi>B</mi> <mn>0</mn> </msub> </mrow> </mfrac> <mo>)</mo> </mrow> </mrow>

Wherein, N₀It is the power spectral density of additive white Gaussian noise, Γ is a constant, referred to as SN space；802.11 In the WLAN of agreement, user accesses WLAN in the way of TDMA；All power transmissions are assumed, and user i is in j-th of WLAN Middle data transmission rate is represented as r_ij, similarly in above formula, r_ijIt is represented as：

<mrow> <msub> <mi>r</mi> <mrow> <mi>i</mi> <mi>j</mi> </mrow> </msub> <mo>=</mo> <msub> <mi>&beta;</mi> <mi>j</mi> </msub> <msub> <mi>B</mi> <mi>j</mi> </msub> <msub> <mi>log</mi> <mn>2</mn> </msub> <mrow> <mo>(</mo> <mn>1</mn> <mo>+</mo> <mfrac> <mrow> <msub> <mi>P</mi> <mrow> <mi>i</mi> <mi>j</mi> </mrow> </msub> <msup> <mrow> <mo>|</mo> <msub> <mi>h</mi> <mrow> <mi>i</mi> <mi>j</mi> </mrow> </msub> <mo>|</mo> </mrow> <mn>2</mn> </msup> </mrow> <mrow> <msub> <mi>&Gamma;N</mi> <mn>0</mn> </msub> <msub> <mi>B</mi> <mi>j</mi> </msub> </mrow> </mfrac> <mo>)</mo> </mrow> </mrow>

Step 2：The difference required according to service delay, M MMT is divided into two types：First kind DC type MMT, quantity is K, the minimum transmission rate request of its business is(i=1,2 ..., K)；Second Type has (M-K) individual BE types MMT, although There is no delay constraint, carried out data transmission in the way of doing one's best, but transmission rate is constrained by proportionality fair play

DC type MMT and BE types MMT condition is expressed as：

<mrow> <msub> <mi>r</mi> <mi>i</mi> </msub> <mo>&GreaterEqual;</mo> <msubsup> <mi>R</mi> <mi>i</mi> <mi>min</mi> </msubsup> <mo>,</mo> <mi>i</mi> <mo>=</mo> <mn>1</mn> <mo>,</mo> <mn>2</mn> <mo>,</mo> <mo>...</mo> <mo>,</mo> <mi>K</mi> <mo>,</mo> </mrow>

r_K+1:r_K+2:...:r_M=γ_K+1:γ_K+2:...:γ_M；

<mfenced open='' close=''> <mtable> <mtr> <mtd> <mi>Max</mi> </mtd> <mtd> <munderover> <mi>&Sigma;</mi> <mrow> <mi>i</mi> <mo>=</mo> <mn>1</mn> </mrow> <mi>M</mi> </munderover> <msub> <mi>R</mi> <mi>i</mi> </msub> </mtd> </mtr> </mtable> </mfenced>

<mfenced open = "" close = ""> <mtable> <mtr> <mtd> <mrow> <mi>s</mi> <mi>u</mi> <mi>b</mi> <mi>j</mi> <mi>e</mi> <mi>c</mi> <mi>t</mi> <mi> </mi> <mi>t</mi> <mi>o</mi> </mrow> </mtd> <mtd> <mrow> <munderover> <mo>&Sigma;</mo> <mrow> <mi>j</mi> <mo>=</mo> <mn>0</mn> </mrow> <mi>L</mi> </munderover> <msub> <mi>&alpha;</mi> <mrow> <mi>i</mi> <mi>j</mi> </mrow> </msub> <mo>&le;</mo> <mn>1</mn> <mo>,</mo> <mo>&ForAll;</mo> <mi>i</mi> <mo>,</mo> <msub> <mi>&alpha;</mi> <mrow> <mi>i</mi> <mi>j</mi> </mrow> </msub> <mo>&Element;</mo> <mo>{</mo> <mn>0</mn> <mo>,</mo> <mn>1</mn> <mo>}</mo> <mo>,</mo> <mo>&ForAll;</mo> <mi>i</mi> <mo>,</mo> <mi>j</mi> </mrow> </mtd> </mtr> </mtable> </mfenced>

<mrow> <munderover> <mo>&Sigma;</mo> <mrow> <mi>i</mi> <mo>=</mo> <mn>1</mn> </mrow> <mi>M</mi> </munderover> <msub> <mi>f</mi> <mrow> <mi>i</mi> <mi>n</mi> </mrow> </msub> <mo>&le;</mo> <mn>1</mn> <mo>,</mo> <mo>&ForAll;</mo> <mi>n</mi> <mo>,</mo> <msub> <mi>f</mi> <mrow> <mi>i</mi> <mi>n</mi> </mrow> </msub> <mo>&Element;</mo> <mo>{</mo> <mn>0</mn> <mo>,</mo> <mn>1</mn> <mo>}</mo> <mo>,</mo> <mo>&ForAll;</mo> <mi>i</mi> <mo>,</mo> <mi>n</mi> </mrow>

<mrow> <munderover> <mo>&Sigma;</mo> <mrow> <mi>i</mi> <mo>=</mo> <mn>1</mn> </mrow> <mi>M</mi> </munderover> <msub> <mi>t</mi> <mrow> <mi>i</mi> <mi>j</mi> </mrow> </msub> <mo>&le;</mo> <mn>1</mn> <mo>,</mo> <mo>&ForAll;</mo> <mi>j</mi> <mo>,</mo> <mn>0</mn> <mo>&le;</mo> <msub> <mi>t</mi> <mrow> <mi>i</mi> <mi>j</mi> </mrow> </msub> <mo>&le;</mo> <mn>1</mn> <mo>,</mo> <mo>&ForAll;</mo> <mi>j</mi> <mo>,</mo> <mi>i</mi> </mrow>

<mrow> <msub> <mi>R</mi> <mi>i</mi> </msub> <mo>=</mo> <munderover> <mo>&Sigma;</mo> <mrow> <mi>n</mi> <mo>=</mo> <mn>1</mn> </mrow> <mi>N</mi> </munderover> <msub> <mi>f</mi> <mrow> <mi>i</mi> <mi>n</mi> </mrow> </msub> <msub> <mi>r</mi> <mrow> <mn>0</mn> <mi>i</mi> <mi>n</mi> </mrow> </msub> <mo>+</mo> <munderover> <mo>&Sigma;</mo> <mrow> <mi>j</mi> <mo>=</mo> <mn>1</mn> </mrow> <mi>L</mi> </munderover> <msub> <mi>t</mi> <mrow> <mi>i</mi> <mi>j</mi> </mrow> </msub> <msub> <mi>r</mi> <mrow> <mi>i</mi> <mi>j</mi> </mrow> </msub> </mrow>

<mrow> <msub> <mi>R</mi> <mi>i</mi> </msub> <mo>&GreaterEqual;</mo> <msubsup> <mi>R</mi> <mi>i</mi> <mi>min</mi> </msubsup> <mo>,</mo> <mo>&ForAll;</mo> <mi>i</mi> <mo>=</mo> <mn>1</mn> <mo>,</mo> <mn>2</mn> <mo>,</mo> <mo>...</mo> <mo>,</mo> <mi>K</mi> </mrow>

<mrow> <mfrac> <msub> <mi>R</mi> <mi>i</mi> </msub> <msub> <mi>&gamma;</mi> <mi>i</mi> </msub> </mfrac> <mo>=</mo> <mfrac> <msub> <mi>R</mi> <mrow> <mi>K</mi> <mo>+</mo> <mn>1</mn> </mrow> </msub> <msub> <mi>&gamma;</mi> <mrow> <mi>K</mi> <mo>+</mo> <mn>1</mn> </mrow> </msub> </mfrac> <mo>,</mo> <mo>&ForAll;</mo> <mi>i</mi> <mo>&Element;</mo> <mi>K</mi> <mo>+</mo> <mn>1</mn> <mo>,</mo> <mi>K</mi> <mo>+</mo> <mn>2</mn> <mo>,</mo> <mn>...</mn> <mo>,</mo> <mi>M</mi> <mo>;</mo> </mrow>

Step 4：Define ρ_ijUser i is represented in network j, wherein 1≤j≤N refers to LTE network, N+1≤j≤N+L refers to j-th Time frame allocation of parameters in WLAN, and introduce a variable s_ij, make s_ij=ρ_ijP_ij, define α_ij=| h_ij|²/Γ_kN₀B_j, And by time frame allocation of parameters ρ_ij, by R_iIt is rewritten asConstraints is rewritten as

<mrow> <mfrac> <msub> <mi>R</mi> <mi>i</mi> </msub> <msub> <mi>&gamma;</mi> <mi>i</mi> </msub> </mfrac> <mo>=</mo> <mfrac> <msub> <mi>R</mi> <mrow> <mi>K</mi> <mo>+</mo> <mn>1</mn> </mrow> </msub> <msub> <mi>&gamma;</mi> <mrow> <mi>K</mi> <mo>+</mo> <mn>1</mn> </mrow> </msub> </mfrac> <mo>,</mo> <mo>&ForAll;</mo> <mi>i</mi> <mo>&Element;</mo> <mi>K</mi> <mo>+</mo> <mn>1</mn> <mo>,</mo> <mi>K</mi> <mo>+</mo> <mn>2</mn> <mo>,</mo> <mo>...</mo> <mo>,</mo> <mi>M</mi> </mrow>

<mrow> <munderover> <mo>&Sigma;</mo> <mrow> <mi>i</mi> <mo>=</mo> <mn>1</mn> </mrow> <mi>M</mi> </munderover> <munderover> <mo>&Sigma;</mo> <mrow> <mi>j</mi> <mo>=</mo> <mn>1</mn> </mrow> <mrow> <mi>N</mi> <mo>+</mo> <mi>L</mi> </mrow> </munderover> <msub> <mi>s</mi> <mrow> <mi>i</mi> <mi>j</mi> </mrow> </msub> <mo>=</mo> <msub> <mi>P</mi> <mi>T</mi> </msub> </mrow>

<mrow> <munderover> <mo>&Sigma;</mo> <mrow> <mi>i</mi> <mo>=</mo> <mn>1</mn> </mrow> <mi>M</mi> </munderover> <msub> <mi>&rho;</mi> <mrow> <mi>i</mi> <mi>j</mi> </mrow> </msub> <mo>=</mo> <mn>1</mn> <mo>,</mo> <mo>&ForAll;</mo> <mi>j</mi> </mrow>

<mrow> <msub> <mi>s</mi> <mrow> <mi>i</mi> <mi>j</mi> </mrow> </msub> <mo>&GreaterEqual;</mo> <mn>0</mn> <mo>,</mo> <mn>0</mn> <mo>&le;</mo> <msub> <mi>&rho;</mi> <mrow> <mi>i</mi> <mi>j</mi> </mrow> </msub> <mo>&le;</mo> <mn>1</mn> <mo>,</mo> <mo>&ForAll;</mo> <mi>i</mi> <mo>,</mo> <mi>j</mi> <mo>;</mo> </mrow>

Step 5：Using the Lagrangian of primal problem to s_ijSeeking partial differential, then result is updated to Caro needs-Ku En-tower In gram (Karush-Kuhn-Tucker, KKT) condition, you can obtain

Step 6：Using GRADIENT PROJECTION METHODS, the optimum performance response for obtaining bandwidth isAnd S is obtained by the conclusion in step 5_ij；

Step 7：Consider the continuous differential expression of the dual function of primal problem, optimization object function is updated using gradient projection method Non-negative Lagrange multiplier, obtains suitable ρ_ijAnd s_ijAfterwards, the optimization solution of object function is obtained；

Wherein, B₀Represent subcarrier bandwidth, B_jRepresent j-th of WLAN bandwidth, α_ijRepresent that user i selects ginseng in network j network Number, f_inRepresent resource allocation parameters of the user i in LTE resource block n, t_ijRepresent user i j-th wlan network when Between frame allocation of parameters, r_0inRepresent user i obtained based on resource block n transfer rate, s_ijRepresent that the actual occupancy of user i is distributed J-th of the subcarrier (1≤j≤N) or power, the v of j-th of WLAN (N+1≤j≤N+L) arrived_iIt is the non-negative of constraints with μ Lagrange multiplier, δ are variable ρs_ijConstant iteration step length, MMT represent that multimode terminal, DC represent that delay constraint type, BE are represented Do one's best type.

2. a kind of optimization Radio Resource pipe based on time delay differentiated service and proportionality rate constraint according to claim 1 Reason method, it is characterised in that：Methods described includes setting up LTE-WLAN heterogeneous network system models.

3. a kind of optimization Radio Resource pipe based on time delay differentiated service and proportionality rate constraint according to claim 1 Reason method, it is characterised in that methods described is to be from physical layer by delineation of activities：Delay constraint type business and type industry of doing one's best Business.

4. a kind of optimization Radio Resource pipe based on time delay differentiated service and proportionality rate constraint according to claim 3 Reason method, it is characterised in that methods described is, come differentiated service type, to introduce timesharing and be total to using business to Qos different demands Variable is enjoyed, the result after synthesis is applied in resource allocation by multistep checking result of calculation.