CN103237309A - Quasi-dynamic frequency resource classification method for interference coordination of LTE-A (Long Term Evolution-Advanced) relay system - Google Patents

Abstract

The invention belongs to the field of wireless communication frequency resource management, and discloses a quasi-dynamic frequency resource classification method for interference coordination of an LTE-A (Long Term Evolution-Advanced) relay system. The quasi-dynamic frequency resource classification method comprises the following steps of initializing the system; planning a usable frequency resource in a cell; collocating the frequency resource in the cell; carrying out interference calculation; calculating SINRs (Signal to Interference plus Noise Ratios) of a user device in different positions in the cell; repetitively calculating SINR situation of the user device in the cell after the position of a relay station is changed; changing the communication environment into an OFDMA (Orthogonal Frequency Division Multiple Access)-based LTE-A communication system relay down link, and enabling the user device to obey uniform distribution between the position where the relay station is located and a cell edge; calculating spectrum effectiveness; calculating average spectrum effectiveness of a current method; and repetitively carrying out spectrum calculation until the trend of an average spectrum effectiveness curve is bright and clear. According to the quasi-dynamic frequency resource classification method disclosed by the invention, by planning the frequency resource in the cell, distributing a part of the resource as original resource and establishing a quasi-dynamic distribution mechanism for managing residue resource, the user communication quality is increased.

Description

The accurate dynamic frequency resource dividing method that is used for LTE-A relay system interference coordination

Technical field

The invention belongs to wireless communication frequency resource management field, relate to a kind of accurate dynamic frequency resource dividing method based on resource multiplex and scheduling.

Background technology

In nearly decades, along with the continuous increase of people to the mobile communication demand for services, mobile communication has obtained swift and violent development.In the first generation (1G) and the second generation (2G) mobile communication system, communication service mainly is based on traditional voice service.And in the third generation (3G) wide-band mobile communication system, because the development of Packet data service, make to have voice service and data service simultaneously in the system.Along with cell mobile communication systems towards high transfer rate more, more the direction of high spectrum utilization and bigger throughput of system develops, 3GPP is in order to tackle based on OFDM (Orthogonal Frequency Division Multiplexing, OFDM) market competition of broadband wireless access technologys such as the WiMAX of technology and Wi-Fi, begun universal mobile telecommunications system (Universal Mobile Telecommunications System the end of the year 2004, UMTS) and System Architecture Evolution (System Architecture Evolution, SAE) Long Term Evolution (Long Term Evolution, LTE) project, and after 4 years, started follow-up evolution (LTE-Advanced) project of LTE.On the basis that seamlessly transits from LTE, LTE-Advanced(is called for short LTE-A) introduced relaying (Relay), carrier aggregation (Carrier Aggregation, CA), cooperative multipoint transmission and reception (Coordinated Multi-Point transmission/reception, CoMP), key technology such as up-downgoing MIMO expansion, with further lifting network performance, improve the user for the experience of mobile communication business, reduce networking and O﹠M cost.

Owing to introduced relaying technique in the LTE-A system, make that the coverage of cell base station (BS) is enlarged, the portable terminal (UE) that is positioned at cell edge or communication blind spot region can carry out double bounce even multi-hop communication to promote its communication quality by access relay station (RS).Bring certain performance gain though relaying technique is communication system, owing to increased the communication link in the residential quarter, need be equipped with extra frequency resource for it, therefore introduced more interference.Because frequency planning is unreasonable, make and have the frequency close with this website operating frequency in neighbor cell or this residential quarter in the contiguous website (base station or relay station), perhaps this website or the adjacent sites coverage that causes based on certain factor is bigger than former designing requirement, and the interference that produces all belongs to adjacent and disturbs frequently.And carrier frequency is identical because the carrier frequency that transmits of other website and this website transmit, and the interference that receiving node is impacted is called co-channel interference.

In the LTE-A communication system, have two class co-channel interferences: the first kind is co-channel interference in the residential quarter, i.e. the interference that different websites use same frequency that receiving node is caused in the residential quarter.Because the LTE-A system has transmission and multiple access technology based on OFDM, therefore relatively reasonable as long as frequency resource is divided, disturbing in the residential quarter just can not be very outstanding; Second class is the minizone co-channel interference, and namely the transmitting node in neighbor cell website and this residential quarter uses the interference that same frequency causes receiving node, and this type of disturbs and is the main interference in the LTE-A communication system.In order to reduce presence of intercell interference, pertinent literature has proposed technology such as interference coordination, multi-cell cooperating.Wherein interference coordination have that realization is comparatively simple, the business that can be applied to various bandwidth, for disturbing the characteristics that suppress to have better effects, resource multiplex and scheduling then are one of important realization approach of interference coordination.

The paper that W.Lee etc. deliver at CCNC2008.5th IEEE " An orthogonal resource allocation algorithm to improve the performance of OFDMA-based cellular wireless systems using relays " Liang Min doctorate paper in 2010 " channeling in the wireless relay network and relay selection research ", in the paper pertinent literatures of delivering at Southwest Jiaotong University's journal in 2011 with Yang Li Na such as " adaptive resource allocation algorithm simulation studies in the LTE-A relay system ", all the frequency resource management to the LTE-A system has had comparatively deep research.The ORAA(Orthogonal Resource Allocation Algorithm of propositions such as W.Lee) method is divided into three parts with frequency range, relay station in the residential quarter in the common sector uses the part of whole resources, residual resource is used in base station in this sector, relay station in the different sectors uses the resource difference, and the resource part that use the base station is identical.The method that the W.Lee of Liang Min proposes is improved, and has proposed improving one's methods of two kinds of ORAA, and two kinds of relay stations of improving one's methods all adopt the directional antenna with certain argument.Improve one's methods and one frequency resource is divided into six parts uses; Each relay station uses 1/6 of whole frequency resources; The frequency resource of relay station non-conterminous 1/3 in base station use and this sector.Improving one's methods two is divided into 3 parts with frequency resource and uses, 1/3 of each relay station frequency of utilization resource, and with relay station frequency of utilization resource difference in the sector.The frequency resource different with relay station in this sector used in the base station.The RRIAS(RS-RS Interference Avoiding Scheme that Yang Lina proposes) with BRIAS(BS-RS Interference Avoiding Scheme) method, frequency resource has all been made finer division, and solved the interference of relay well interference and base station and relay well respectively to a certain extent, but when obtaining this aspect advantage, ignored the optimization on the other hand.The described method of above document lacks for frequency resource utilance in the inhibition of disturbing in the system and the residential quarter to be considered as a whole, and resource distribution mode fixes, dumb, can not adapt to the communication environment of variation.

Summary of the invention

At the inhibition to two kinds of interference in the LTE-A communication system that exists in the prior art, and frequency resource utilance shortage is considered as a whole in the residential quarter, resource distribution mode fixes, dumb, the problems such as communication environment that can not adapt to variation, the present invention has proposed a kind of accurate dynamic frequency resource division methods for LTE-A relay system interference coordination in conjunction with concepts such as resource nargin and resource distribution.

The present invention is by whole frequency resources in the careful planning residential quarter, and reasonable distribution part resource distributes as initial resource, sets up accurate dynamic distribution mechanism to manage the residue idling-resource, reaches the purpose that improves user communication quality.The present invention includes following steps:

Step 1 is carried out initialization to system, and method is as follows:

(1) setting the communication network model is 7 residential quarter double bounce OFDM junction network models, and the setting communication environment is the LTE-A down link based on the OFDMA technology;

(2) relay station that the base station cooperates with participation in the setting communication cell is as transmitting node, and subscriber equipment is as receiving node;

(3) set cell base station and relay station antenna and all adopt the directional antenna with certain argument, 2 * 2 patterns are taked in the antenna configuration, and setting power is fixed and satisfied certain ratio;

(4) communication mode of setting relay station is half duplex mode of communication;

(5) set subscriber equipment and obey evenly distribution at radius of society.

Step 2, available frequency resources in the planning residential quarter, method is as follows:

(1) whole resources evenly is divided into 20 less frequency resource f _j

(2) definition Ω _iBe a continuous group of frequencies of frequency physically, and with f _jConclude Ω _iIn; Subsequently according to the potential application band present situation configuration of LTE-A communication system Ω _iAffiliated frequency range;

(3) defined notion group F _iBe the discontinuous class frequency Resource Block of frequency resource in organizing, and with f _jConclude F again _iIn distribute in order to finish resource.

Frequency resource in the step 3, allocating cell, method is as follows:

(1) according to F _iConfiguration in the residential quarter on base station and the relay station, each F attaches troops to a unit _iIn f _jTo obtain frequency initial distribution of the present invention;

(2) set the dynamic idling-resource distribution mechanism of standard, distribute idle f according to communication requirement _jAsk website, and detect the idle f that has used _iWhether not busy in distributing website to dispose, put the spare time and then regain this f _i

Step 4 is taked to carry out interference calculation based on transmitting node to the average path loss model of receiving node geometric distance, and method is as follows:

The useful signal received power P of receiving node j _jCan be expressed as:

P _j＝g _ij×P _i(1)

In the formula, P _iBe the transmitting power of sending node, g _IjBe the signal fadeout from the transmitting node to the receiving node.

With the g in the following formula _IjBe refined as average path loss PL:

$\mathrm{PL}={\left(\frac{4\mathrm{\π}{d}_{0}f}{c}\right)}^2{\left(\frac{d}{d_0}\right)}^{\mathrm{\η}}---\left(2\right)$

In the formula, d ₀Be reference distance; F is carrier frequency; C is the light velocity; D is the geometric distance between sending node and the receiving node; η is spread index.

Step 5 is calculated as follows in the residential quarter subscriber equipment at the Signal Interference and Noise Ratio SINR(Signal of diverse location to Interference plus Noise Ratio):

In the formula, I _jBe external disturbance; v _jAdditive white Gaussian noise for the receiving node place;

Being orthogonal factor, is 0 in the OFDMA system.

Step 6, the change repeating station spacing also repeats step 5, obtains the SINR of subscriber equipment in the repeating station spacing residential quarter after changing.By comparing the SINR of user under the different repeating station spacings, select the optimal location of relay station.

Step 7 changes communication environment into based on OFDMA LTE-A communication system relaying down link, and sets subscriber equipment and obeys evenly distribution between relay station present position and cell edge.

Step 8 is calculated as follows spectrum efficiency k:

k＝log ₂(1+Kγ)(4)

$K=\frac{1.5}{\ln (0.2/{\mathrm{BER}}^{\mathrm{tar}})}---\left(5\right)$

In the formula, γ is the SINR of receiving node; BER ^TarBe error rate threshold value.

Step 9, the average of all trunk subscriber spectrum efficiencies under kind of the method for seeking common ground obtains the average spectral efficiency (ase) of current method.

Step 10, repeating step eight, nine, the user's average spectral efficiency (ase) under the method for seeking common ground, each total number of users increases progressively 10, and is bright and clear until the average spectral efficiency (ase) curvilinear trend.

The invention has the beneficial effects as follows: by to the making rational planning for and allocating of frequency resource in the residential quarter, reduced the number in co-channel interference source, avoided that part is adjacent to be disturbed frequently, improved user's SINR and average spectral efficiency (ase) in the residential quarter.Distribute by the dynamic idle frequence resource of standard, make that the component frequency resource is able to flexible allotment in the residential quarter, improved the utilance of frequency resource.

Description of drawings

Fig. 1 is method flow diagram involved in the present invention;

Fig. 2 is LTE-A relay cellular network model schematic diagram;

Fig. 3 is usable frequency planning schematic diagram;

Fig. 4 is concept class frequency configuration schematic diagram;

Fig. 5 is that concrete frequency resource is divided schematic diagram;

Fig. 6 is frequency initial distribution schematic diagram;

Fig. 7 dynamic idling-resource scheduling flow figure that is as the criterion;

Fig. 8 is method direct transmission user disturbed condition figure involved in the present invention;

Fig. 9 is method trunk subscriber disturbed condition figure involved in the present invention;

Figure 10 is the SINR comparison diagram of user's diverse location in the residential quarter, among the figure:

The SINR curve of representing method involved in the present invention, The SINR curve of expression control methods ORAA, Improve one's methods one SINR curve of expression control methods ORAA,

Improve one's methods two SINR curve of expression control methods ORAA;

Figure 11 is the SINR comparison diagram of repeating station spacing after changing, and the implication represented of synteny is not the same;

Figure 12 is trunk subscriber average spectral efficiency (ase) comparison diagram, among the figure:

The average spectral efficiency (ase) curve of representing method trunk subscriber involved in the present invention,

The average spectral efficiency (ase) curve of expression control methods ORAA trunk subscriber,

The improve one's methods average spectral efficiency (ase) curve of a trunk subscriber of expression control methods ORAA, The improve one's methods average spectral efficiency (ase) curve of two trunk subscribers of expression control methods ORAA.

Embodiment

Method flow diagram of the present invention may further comprise the steps as shown in Figure 1:

Step 1, system is carried out initialization: for 7 residential quarter double bounce OFDM junction network models, setting the communication cell radius is R=1000m, each residential quarter is divided 3 sectors altogether, the base station is positioned at center of housing estate, along 6 relay stations of regular hexagon diagonal symmetrical distribution of cellular cell, the distance between all relay stations and cell base station is L, and temporarily chooses L=2R/3.Based on the half-duplex characteristic of wireless relay network, consider that two links of BS-RS and BS-UE communicate at first time slot when the user selects to insert relay station, the RS-UE link communicates at second time slot.The transmitting power of fixed cells base station and relay station also determines that its ratio is 0.6, and the transmitting antenna of base station and each relay station is the directional antenna with certain argument in the residential quarter.Evenly distribution of distance obedience between subscriber equipment basis and base station in the residential quarter.Set according to the maximum system bandwidth of LTE-A system that available frequency resources F is 100MHz in the residential quarter.

Step 2 is divided and it is made regulation available frequency resources in the residential quarter, and method is as follows:

(1) for the ease of the allotment of subsequent step for frequency resource, earlier available frequency resources in the residential quarter evenly is divided into a plurality of f _j, wherein, f _j=5MHZ,

J=1,2 ..., 20.

(2) F is divided into 7 Ω _i, namely Set each Ω _iDiscrete mutually, in order to solve the adjacent interference problem frequently in the communication cell.Set Ω ₁～Ω ₆Be the original frequency group, be used for determining that the original frequency of this method distributes; Set Ω ₇For noiseless nargin and persisted.Based on the characteristic distributions that has three websites (cell base station and two relay stations) in the same sector in the residential quarter, set each Ω in the original frequency group _i3 f of interior configuration _jRemaining f ₁₉With f ₂₀Ω is given in configuration ₇Distribute as idling-resource.All frequency resource program resultses as shown in Figure 3 in the residential quarter.

(3) F is divided into again 4 F _i, i=1,2,3,4, i.e. F=F ₁∪ F ₂∪ F ₃∪ F ₄, and

Set F ₁～F ₃Be used for determining that original frequency distributes; F ₄For reserving nargin, i.e. F ₄=Ω ₇For F ₁～F ₃, set every group and have 6 f _j, and meet f _3j-2∈ F ₁, f _3j-1∈ F ₂, f _3j∈ F ₃, j=1,2 ..., 6.

Frequency resource, the i.e. f that has divided in the step 2 in the step 3, allocating cell _jWith F _i, method is as follows:

(1) based on the deployment scenario of base station and relay station, with F ₁～F ₃Distribute to repeating query three websites in each sector, and be positioned at the different F of website use of same position _i, namely guarantee F wherein _RSaWith F _RSbRepresent the F that two relay stations in the same sector use respectively _i, F _BSRepresent the F that use the base station in this sector _iFrequency initial distribution basis as shown in Figure 4.Subsequently according to the F that has obtained _iDistribution is with F ₁～F ₃Interior f _jDistribute to repeating query each website and obtain the allocation result shown in accompanying drawing 5, and the frequency initial distribution of this method in the accompanying drawing 6.Accompanying drawing 5 is divided and two angles of concept class frequency division from whole frequency resource, has shown all f _jFor F _iOwnership result and uses thereof.F among the figure _jThe side all indicates its position of attaching troops to a unit in the residential quarter, and " XX " shows this f _jBe not assigned with as yet.Because the frequency resource difference that each website uses in the residential quarter, so there is not co-channel interference substantially in inside, residential quarter.

(2) according to flow chart shown in the accompanying drawing 7 unappropriated frequency resource in the step 3 (1) is allocated:

A. preferentially call idle noiseless nargin Ω ₇

B. work as Ω ₇Whole when occupied, base station or the used F of relay station of preferential call request resource _iInterior f _jGive this website;

C. the base station or the used F of relay station that work as request resource _iInterior f _jWhen all occupied, call other idle f _j

D. as request distribution f _jWebsite when being relay station, the communication mode based on the relaying cooperation also need distribute f _i(i ≠ j) gives the base station of this sector, relay station place, f _iAlso preferentially select the used F in this base station _iInterior Resource Block;

E. the idling-resource f that calls _jAs far as possible the frequency resource of not used with website on every side is at same Ω _iIn;

F. ought obtain idling-resource f _jWebsite when no longer needing this resource, discharge f immediately _jTo supply other website demand;

If g. discharge f _jWebsite be relay station, then corresponding base station also should discharge f simultaneously with it _i

H. the f that has disposed in the initial distribution _jCan not discharge.

Step 4 is taked to carry out interference calculation based on transmitting node to the average path loss model of receiving node geometric distance.For the computing formula of average path loss PL as the formula (2), in the formula, reference distance d ₀Be made as 10m, carrier frequency f is made as 2GHz; Light velocity c is made as 3 * 10 ⁸M/s; D is the sending node of being calculated by Pythagorean theorem and the geometric distance between the receiving node.Since this method with BS-RS, BS-UE and three links of RS-UE all be made as visual link (Line of Sight, LOS), therefore, η=LOS=2.

Step 5 is calculated as follows the SINR of receiving node:

$\mathrm{\γ}=\frac{P_x/\mathrm{PL}\left(L_x\right)}{{\mathrm{\Σ}}_{i=a}^b{P}_{\mathrm{Bi}}/P\left(L_{\mathrm{Bi}}\right)+{\mathrm{\Σ}}_{j=c}^d{P}_{\mathrm{Rj}}\left(L_{\mathrm{Rj}}\right)}---\left(6\right)$

In the formula, P _xBe the transmitting power of transmitting node, L _xBe the geometric distance of transmitting node to destination node, x ∈ { BS, RS}; P _BiWith P _RjBe respectively the base station of serving as interference source and the transmitting power of relay station, L _BiAnd L _RjBe respectively the base station of interference source and relay station to the geometric distance of receiving node, a, b, c, d ∈ 1,2 ..., 20}.

Since in this method in the residential quarter transmitting antenna of base station and each relay station be the directional antenna with certain argument, therefore the disturbed condition of direct transmission user can be expressed as accompanying drawing 8, the interference that is direct transmission user only comes from 3 base stations of using same frequency resources of neighbor cell, and the SINR of direct transmission user can accurately be expressed as then:

${\mathrm{\γ}}_1=\frac{P_B/\mathrm{PL}\left(L_B\right)}{{\mathrm{\Σ}}_{i=1}^3{P}_{\mathrm{Bi}}/\mathrm{PL}\left(L_{\mathrm{Bi}}\right)}---\left(7\right)$

The disturbed condition of trunk subscriber can be expressed as accompanying drawing 9, i.e. 4 relay stations of same frequency resources are only used in the interference of trunk subscriber from neighbor cell, so the SINR of trunk subscriber can accurately be expressed as:

${\mathrm{\γ}}_2=\frac{P_R/\mathrm{PL}\left(L_R\right)}{{\mathrm{\Σ}}_{j=1}^4{P}_{\mathrm{Rj}}/\mathrm{PL}\left(L_{\mathrm{Rj}}\right)}---\left(8\right)$

Step 6 is made as R/2 with L, and repeating step five obtains the SINR situation of subscriber equipment in the repeating station spacing residential quarter after changing.The situation of L=2R/3 and the situation of L=R/2 are compared, choose the relay station optimal location as required.Situation as L=R/2 is still undesirable, can continue to choose L until satisfying the demands.

Step 7 changes communication environment into based on OFDMA LTE-A communication system relaying down link, and L is reset to 2R/3, and subscriber equipment is obeyed between relay station present position and cell edge evenly and distributed.

Step 8 is asked spectrum efficiency k by (2) formula, in the formula, and when L gets 2R/3, BER ^Tar=10 ^-6

Step 9, all trunk subscriber spectrum efficiencies under the method for the same race are averaged obtains the average spectral efficiency (ase) of current method.

Step 10, repeating step eight, nine, each total number of users increases progressively 10, till the average spectral efficiency (ase) curvilinear trend under the Same Way is bright and clear.Be limited to 100 on the selected trunk subscriber sum herein.

Accompanying drawing 10 is to adopt the SINR comparison diagram that method of the present invention and ORAA method, ORAA improve one's methods, ORAA improves one's methods two users that obtain diverse location in the residential quarter.By SINR curve contrast under the distinct methods among the figure as can be seen: the accurate dynamic frequency resource dividing method for LTE-A relay system interference coordination of the present invention, come down to avoid the adjacent relevant regulations of disturbing frequently, the emission argument of relaying station antenna is made restriction by being used for that frequency resource in the residential quarter is carried out, and make more careful division and distribution for frequency resource, promoted user's SINR.It should be noted that: because the deployed position of the method for the invention relay station and the setting of antenna argument, make the SINR of user in the residential quarter along with and cell base station between the increase of distance, be and reduce afterwards to take place the saltus step that makes progress, the trend that reduces again afterwards earlier; And ORAA method as a comparison, because relay station adopts omnidirectional antenna, so according to the relay station relevant parameter, set the user and begin to insert relaying from distance cell base station R/2, therefore the SINR of user in the residential quarter along with and cell base station between the increase of distance, be and reduce earlier afterwards to increase, reach the trend that reduces again behind the peak value.For the method for the invention, in the scope of 0～L, all with per family directly and the base station communicate.In nearer zone, distance base station, user's SINR can reach about 35dB, and at the SINR that still can possess near the zone of L more than the 5dB.In the zone of L～R, all are with selecting to carry out double bounce communication by relay station per family.In saltus step place of SINR curve, near the peak value that direct transmission user obtains the peak value that trunk subscriber obtains and the base station is close, and still can obtain the SINR about 10dB at the cell edge place.As seen from the figure, in 0～R/2 and L～Zone R territory, the present invention compares with three kinds of control methods, has remarkable advantages.

Accompanying drawing 11 is after two repeating station spacings that obtain that adopt that method of the present invention and ORAA method, ORAA improve one's methods, ORAA improves one's methods change, the SINR comparison diagram of user's diverse location in the residential quarter.As seen from the figure: method of the present invention can further promote the SINR performance of user in the residential quarter by adjusting the relay station present position.It should be noted that: because the setting of ORAA method relay station, the user can obtain higher SINR in R/2～2R/3 zone, so the ORAA method occupies certain advantage in this zone.In order to remedy the deficiency of the present invention in this zone, the present invention is suitably mobile to the cell base station direction with repeating station spacing, and particular location can be selected according to actual conditions, herein tentative L=R/2.As can be seen from Figure, close on the 500m place in the distance base station, direct transmission user can obtain the SINR about 8dB.At the about 620m in distance base station place, the method for the invention has obtained identical SINR with the ORAA method, and centered by this point, the SINR curve that is positioned at two kinds of methods of its both sides is symmetrical distribution substantially, and two kinds of methods are close at the SINR numerical value of peak value place acquisition.At the about 750m in distance base station place, two kinds of methods have obtained identical SINR value again.To the Zone R territory, the SINR of the method for the invention is better than the ORAA method again at this point, and has obtained the SINR about 6dB at the R place.

Accompanying drawing 12 be adopt the method for the invention and ORAA method, ORAA to improve one's methods one, ORAA improves one's methods the two trunk subscriber average spectral efficiency (ase) comparison diagrams that obtain.As seen from the figure: the method for the invention can promote the average spectral efficiency (ase) of user in the residential quarter by the SINR that improves receiving node.Compare with three kinds of control methods, the method of the invention has clear superiority, and when the relaying total number of users was 40, average spectral efficiency (ase) had reached 3bps/Hz, and along with the increase average spectral efficiency (ase) of sum continues slowly to increase, be stabilized in about 3.1bps/Hz at last.

Claims (1)

1. accurate dynamic frequency resource dividing method that is used for LTE-A relay system interference coordination, it is characterized in that by whole frequency resources in the planning residential quarter, the distribution portion resource distributes as initial resource, set up the approach of accurate dynamic distribution mechanism management surplus resources, thereby reach the purpose that improves user communication quality; Method of the present invention may further comprise the steps:

Step 1 is carried out initialization to system, and method is as follows:

(1) setting the communication network model is 7 residential quarter double bounce OFDM junction network models, and the setting communication environment is the LTE-A down link based on the OFDMA technology;

(2) relay station that the base station cooperates with participation in the setting communication cell is as transmitting node, and subscriber equipment is as receiving node;

(3) set cell base station and relay station antenna and all adopt the directional antenna with certain argument, 2 * 2 patterns are taked in the antenna configuration, and setting power is fixed and satisfied certain ratio;

(4) communication mode of setting relay station is half duplex mode of communication;

(5) set subscriber equipment and obey evenly distribution at radius of society;

Step 2, available frequency resources in the planning residential quarter, method is as follows:

(1) whole resources evenly is divided into 20 less frequency resource f _j

(2) definition Ω _iBe a continuous group of frequencies of frequency physically, and with f _jConclude Ω _iIn; Subsequently according to the potential application band present situation configuration of LTE-A communication system Ω _iAffiliated frequency range;

(3) defined notion group F _iBe the discontinuous class frequency Resource Block of frequency resource in organizing, and with f _jConclude F again _iIn distribute in order to finish resource;

Frequency resource in the step 3, allocating cell, method is as follows:

(1) according to F _iConfiguration in the residential quarter on base station and the relay station, each F attaches troops to a unit _iIn f _jTo obtain frequency initial distribution of the present invention;

(2) set the dynamic idling-resource distribution mechanism of standard, distribute idle f according to communication requirement _jAsk website, and detect the idle f that has used _iWhether not busy in distributing website to dispose, put the spare time and then regain this f _i

Step 4 is taked to carry out interference calculation based on transmitting node to the average path loss model of receiving node geometric distance, and method is as follows:

The useful signal received power P of receiving node j _jCan be expressed as:

P _j＝g _ij×P _i

In the formula, P _iBe the transmitting power of sending node, g _IjBe the signal fadeout from the transmitting node to the receiving node;

With the g in the following formula _IjBe refined as average path loss PL:

$\mathrm{PL}={\left(\frac{4\mathrm{\π}{d}_{0}f}{c}\right)}^2{\left(\frac{d}{d_0}\right)}^{\mathrm{\η}}$

In the formula, d ₀Be reference distance; F is carrier frequency; C is the light velocity; D is the geometric distance between sending node and the receiving node; η is spread index;

Step 5 is calculated as follows in the residential quarter subscriber equipment at the Signal Interference and Noise Ratio SINR of diverse location:

In the formula, I _jBe external disturbance; v _jAdditive white Gaussian noise for the receiving node place; Being orthogonal factor, is 0 in the OFDMA system;

Step 6, the change repeating station spacing also repeats step 5, obtains the SINR of subscriber equipment in the repeating station spacing residential quarter after changing; By comparing the SINR of user under the different repeating station spacings, select the optimal location of relay station;

Step 7 changes communication environment into based on OFDMA LTE-A communication system relaying down link, and sets subscriber equipment and obeys evenly distribution between relay station present position and cell edge;

Step 8 is calculated as follows spectrum efficiency k:

k＝log ₂(1+Kγ)

$K=\frac{1.5}{\ln (0.2/{\mathrm{BER}}^{\mathrm{tar}})}$

In the formula, γ is the SINR of receiving node; BER ^TarBe error rate threshold value;

Step 9, the average of all trunk subscriber spectrum efficiencies under kind of the method for seeking common ground obtains the average spectral efficiency (ase) of current method;

Step 10, repeating step eight, nine, the user's average spectral efficiency (ase) under the method for seeking common ground, each total number of users increases progressively 10, and is bright and clear until the average spectral efficiency (ase) curvilinear trend.

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