CN101404800B - Semi-static interference coordination method based on void cell in OFDMA cellular system - Google Patents

Abstract

The invention provides a semi-static interference coordination method based on a virtual subdistrict and is suitable for a broadband honeycomb mobile communication system based on OFDMA. The method uses strong mutual interference characteristics between sectors in the virtual subdistrict, takes the virtual district as a basic interference coordination unit, and uses a soft frequency reuse method of an edge frequency bank and a center frequency band being orthometric between the sectors in the virtual subdistrict; the reuse factor frf<C>=1 of a component channel of the center district of each sector and the reuse factor frf<E> of the component channel of the edge district are determined according to the average verge of each sector in the virtual subdistrict and the duty factor of the center district; frf<E> is more than one; the component channel quantity allocation of the centre and the edge of each sector in the virtual subdistrict is determined according to the duty factor of the center and the edge of each sector and is adjusted along with load distribution variation of the virtual subdistrict; the same frequency interference received by the edge area of the sector is reduced by forward planning order of priority of the component channel.

Description

In the OFDMA cellular system based on the method for coordinating semi-static interference of void cell

Technical field

The present invention relates to wireless communication technology field, be specifically related to a kind of based on the disturbance coordination method in the broadband cellular mobile communication system of OFDM.

Background technology

Increasing rapidly of mobile service amount makes people have higher requirement to wireless network.Since multi-carrier modulation technology can optimization system transmission performance, improve power system capacity, in recent years, be the extensive concern that the multi-carrier modulation technology of representative has been subjected to people with OFDM (OFDM).The OFDM technology has been listed in one of main candidate technologies of Beyond 3G system, people just considering with its be used in wireless MAN based on IEEE 802.16 standards, based in the private wireless network of IEEE 802.15 standards and the following radio honeycomb mobile communication system of future generation.

The OFDM technology is a kind of multi-carrier modulation technology, and it is divided into the son stream of several low speed with data flow at a high speed, and transmits respectively on different subcarriers.The cycle of each OFDM symbol will be much larger than the cycle of data symbol like this, and intersymbol interference problem will be alleviated greatly; By in the OFDM symbol, adding protection interval and Cyclic Prefix, can eliminate intersymbol interference and inter-carrier interference in addition.Because the channel fading on each subcarrier of OFDM is relatively independent, can adopt different modulation coding modes on different subcarriers, realizes making full use of of Radio Resource, thereby further improve the efficiency of transmission of system.

In ofdm system, if the employing frequency duplex factor as one is 1 frequency reuse scheme, then the user in the sub-district will be subjected to the stronger interference of neighbor cell.The available signal power that Cell Edge User not only receives a little less than, and the interference that is subjected to also is eager to excel than Cell Center User, therefore, frequency duplex factor as one is that 1 frequency reuse scheme will cause relatively poor relatively service quality in cell edge place and lower data rate.

In order to improve the cell-edge performance of ofdm system, need the effective interference coordination schemes of research.In existing various interference coordination schemes, can improve cell-edge performance preferably based on the interference coordination schemes of soft-frequency reuse, guarantee the fairness between edge customer and the central user.Yet, the distribution that static soft-frequency reuse scheme can not be adjusted frequency flexibly along with the load Distribution situation, thus lower at cell edge and central loading skewness time-frequency spectrum efficient.And existing semi-static scheme mostly needs to have the support of the hierarchical network architecture of RNC, and its basic coordination unit is a plurality of cellular cells under the RNC management, and the flexibility ratio of coordination is lower.Because signaling consumption is too big, the research of relevant dynamic interference coordination is few.

In sum, as can be seen, disturbance coordination method in the past can not well adapt to the requirement of following cell mobile communication systems, can not provide for the individual layer access network structure that lacks RNC a kind of easy realization, disturbance coordination method flexibly and effectively.So, be necessary to study and be applicable to new disturbance coordination method new single layer network structure, that can effectively improve cell edge throughput and system spectrum utilance, optimization system performance.

Summary of the invention

The objective of the invention is to provides a kind of semi-static Inter-Cell Interference Coordination technical scheme for the wide-band mobile communication system based on OFDM, by frequency planning based on load Distribution, when improving Cell Edge User service quality, realize system load balancing, improve the spectrum efficiency of system.Simultaneously, utilize the strong interference characteristic mutually in void cell interior wing interval, with void cell as basic interference coordination unit, carry out coordinating semi-static interference by the information interaction between three sectors in the void cell, the information interaction amount and the system control overhead of minizone when reducing interference coordination, reduce system complexity, for the flat network configuration that lacks RNC provides a kind of simple and effective coordinating semi-static interference realization mechanism.

The present invention is unit with the void cell, adopts the soft-frequency reuse interference coordination schemes of edge frequency range and center frequency range quadrature in each sector of void cell.The subchannel that is about to system is divided into center subchannel and edge subchannel two parts, and subchannel frequency duplex factor as one in the void cell scope in center is 1, is used jointly by the central area user of each sector in the void cell; Subchannel frequency duplex factor as one in void cell in edge is N _SOr N _S/ 2 (N _SBe a sector number that void cell comprises), by the N of void cell _SThe fringe region user of individual sector uses.The frequency duplex factor as one of edge subchannel is decided according to the average margin and center load ratio in the void cell.

Center number of subchannels and the edge number of subchannels of calculating each sector according to the multiplexing factor of center and peripheral sub-channel frequencies and the center and peripheral area load ratio of its each sector in the void cell.

Each sector is chosen the edge subchannel according to required edge number of subchannels according to the preferential selecting sequence of edge subchannel of planning in advance, and then the center subchannel of definite void cell.The subchannel quadrature of basic principle for as far as possible the adjacent sectors fringe region being used of the preferential selecting sequence planning of edge subchannel.

After having determined edge and center subchannel, each sector is that selected subchannel distributes power according to the high power frequency range and the low-power frequency range of planning in advance.The basic principle of high and low power frequency range planning is for making each sector co-channel interference minimum that fringe region is subjected to when selecting the edge subchannel according to the priority of planning in advance as far as possible.

The center number of subchannels and the edge number of subchannels of each void cell are adjusted along with the load variations in the void cell.Because the load Distribution changed condition is slower, can adopt long interval periodically to adjust or upgrade with the pattern of Event triggered, promptly adopt semi-static coordination mode, to reduce system control overhead.

The present invention program's performing step is as follows:

1, initialization: the index and the threshold value of determining to divide central user and edge customer; Plan the preferential selecting sequence of edge subchannel of each sector; Determine to divide the average margin and center load of the void cell ratio threshold value γ of the multiplexing factor of edge sub-channel frequencies _ThPlan the high power frequency range and the low-power frequency range of each sector.

2, determine central user and edge customer: the user in each sector is divided into central user or edge customer two big classes according to the thresholding of predesignating.

3, determine the center number of subchannels and the edge number of subchannels of each sector of void cell: calculate the average margin and center load ratio γ of each sector in the void cell, when γ less than the average margin and center load of void cell ratio threshold value γ _ThThe time, the frequency duplex factor as one frf of sector-edge subchannel _E=N _SWhen γ greater than γ _ThThe time, frf _E=N _S/ 2.The multiplexing factor frf of center sub-channel frequencies of each sector _C=1.Calculate required center number of subchannels and the edge number of subchannels in each sector of void cell according to the frequency duplex factor as one of center and peripheral subchannel and the load ratio in each center and peripheral zone, sector, computational methods are as follows:

$N_C^{\&prime;}=\mathrm{round}[N\&CenterDot;\frac{1}{N_S}\&CenterDot;\underset{i}{\mathrm{\&Sigma;}}\frac{\mathrm{\&alpha;}\&CenterDot;D_{\mathrm{Ci}}}{\mathrm{\&alpha;}\&CenterDot;D_{\mathrm{Ci}}+D_{\mathrm{Ei}}}]$

$N_{\mathrm{Ei}}^{\&prime;}=\mathrm{round}[(N-N_C^{\&prime;})\&CenterDot;\frac{D_{\mathrm{Ei}}}{\underset{i}{\mathrm{\&Sigma;}}{D}_{\mathrm{Ei}}}]$

$N_C=N-\underset{i}{\mathrm{\&Sigma;}}{N}_{\mathrm{Ei}}^{\&prime;}$

Work as frf _E=N _SThe time, N _Ei=N ' _Ei

When ${\mathrm{frf}}_E=\frac{{\mathrm{<figure-callout\; id="2"\; label="N\; S"\; filenames="S2008101017517E00021.png,S2008101017517E00031.png"\; state="\{\{state\}\}">N</figure-callout>}}_S}{2}$ The time, $N_{\mathrm{Ei}}=N_{\mathrm{Ei}}^{\&prime;}+\min \{N_{\mathrm{Ei}}^{\&prime;},\underset{j\&NotEqual;i}{\mathrm{\&Sigma;}}{N}_{\mathrm{Ej}}^{\&prime;}\}$

N _CEach central area, sector number of subchannels of expression void cell, N _EiRepresent i sector-edge zone subchannels number in each void cell, round[A] represent A is carried out round, $\mathrm{\&alpha;}=\frac{{\mathrm{frf}}_C}{{\mathrm{frf}}_E}$ The expression equivalent resources occupation proportion factor, D _CiThe total number of users or the total bandwidth need of central area, i sector in the expression void cell, D _EiTotal number of users in i sector-edge zone or total bandwidth need in the expression void cell (i=1,2 ..., N _S), N represents the total number of subchannels of system, N _SThe sector number that comprises for void cell.

4, determine the edge subchannel of each sector: the sector-edge number of subchannels that obtains according to previous step is that the edge subchannel is chosen in each sector of void cell according to the preferential selecting sequence of planning in advance.

5, determine the center subchannel of void cell: with all are not selected as the center subchannel of the subchannel of edge subchannel as this void cell in the void cell.

6, distribute power: each sector gives more high-power transmission according to the high power frequency range and the low-power frequency range of planning in advance to the subchannel that belongs to its high power frequency range in its selected subchannel, and the subchannel that belongs to its low-power frequency range gives smaller power and sends.

7, regular update: adopt to periodically update or pattern that Event triggered is upgraded, regularly adjust the center subchannel and the edge subchannel of each void cell.Renewal process is finished by repeating aforementioned 2～6 steps.

Description of drawings

Referring now to accompanying drawing 1～6 explanation embodiments of the invention.

Fig. 1 has shown the present invention program's realization flow figure.

Fig. 2 has shown the void cell in the hexagon cellular cell system of 120 ° of sectorization.

Fig. 3 has shown according to sector number schematic diagram of the present invention.

Fig. 4 has shown the exemplary planning according to the preferential selecting sequence of edge subchannel of different numberings of the present invention sector.

Fig. 5 has shown according to two kinds of exemplary sub-channel group technologies of the present invention.

Fig. 6 has shown the high and low power frequency range division according to different numberings sector in the example of the present invention.

Fig. 7 has shown that certain void cell carries out an example of frequency, power programming, wherein sector-edge sub-channel frequencies multiplexing factor frf according to this programme _E=3.

Fig. 8 has shown that certain void cell carries out an example of frequency, power programming, wherein sector-edge sub-channel frequencies multiplexing factor frf according to this programme _E=3/2.

Embodiment

Fig. 1 has shown the present invention program's realization flow figure.

Be example hereinafter, the specific embodiment of the present invention be described according to the present invention program's performing step with the void cell structure in 120 ° of sectorization hexagon cellular cell systems.

Fig. 2 has shown the void cell in the hexagon cellular cell system of 120 ° of sectorization.

In the hexagon cellular cell system of 120 ° of sectorization, when the antenna direction of each sector all points to the intersection of two neighbor cells, then each sector all can constitute a hexagonal void cell with adjacent with it two sectors in the neighbor cell, as shown in Figure 2,1,6,8 three sector among the figure can constitute a hexagonal void cell.

The present invention adopts based on the edge frequency range of void cell scope and the soft-frequency reuse scheme of center frequency range quadrature, promptly in each void cell, the subchannel of system is divided into center subchannel and edge subchannel two parts, subchannel frequency duplex factor as one in the void cell scope in center is 1, is used jointly by the central user of three sectors of void cell; The frequency duplex factor as one of edge subchannel in void cell will or be decided to be 3 or be decided to be 3/2 according to the size of the average margin and center load of this void cell ratio, and the edge customer by three sectors uses respectively.Because subchannel frequency repeat utilization ratio in void cell in edge is lower, so the co-channel interference from adjacent sectors in the void cell that edge customer is subjected to is less, edge performance is improved.Concrete implementation step is as follows:

One, initialization

1. determine to divide the index of central user and edge customer and divide thresholding

(Carrier To Interference Ratio, the distance C/I) or between user and base station is got certain value as dividing thresholding then as dividing index can to select user's average link carrier/interface ratio.

2. plan the preferential selecting sequence of edge subchannel of each sector

Planning the purpose of the preferential selecting sequence of edge subchannel for each sector is in order to reduce as far as possible from the outer edge co-channel interference of this void cell.A planing method of the present invention is as follows:

At first, the sector in all sub-districts is numbered according to identical mode, makes that the numbering of the sector that all positions are adjacent is all inequality, separate by a sector at least and have between two sectors of identical numbering.Fig. 3 has shown according to a sector number example of the present invention.

Then, be the different preferential selecting sequence of edge subchannel of difference numbering sector planning.

Because after adopting soft-frequency reuse scheme based on void cell, the edge co-channel interference in void cell interior wing interval will be eliminated (when the frequency duplex factor as one of edge frequency range is 3) fully or significantly reduce (when the frequency duplex factor as one of edge frequency range is 3/2), and the main interference that each sector-edge user is subjected to will come from the sector of the outer different numberings of this void cell.As shown in Figure 3, be numbered main interference that 1 sector is subjected to and will come from its void cell and be numbered 2 and 3 sector outward, wherein Zui Da two interference sectors are two other sectors in its real sub-district.For the preferential selecting sequence of each sector planning edge subchannel the time, adopt the identical preferential selecting sequence of edge subchannel if make the identical sector of all numberings, then the edge subchannel of all identical numbering sectors will overlap substantially, the center subchannel of all sectors also overlaps substantially, and edge subchannels of all different numberings sectors are basic quadrature, and the interference outward from this void cell that sector-edge user is subjected to significantly reduces.

Fig. 4 has provided the preferential selecting sequence planning of a kind of edge subchannel example, and supposing the system comprises 24 subchannels in the example, all is used for transfer of data.System's available subchannels is divided into equal-sized 3 groups of subchannels, this 3 groups of subchannels are used according to different priority orders in different numberings sector when choosing the edge subchannel, and the order of choosing subchannel in same groups of subchannels is also inequality, chooses order shown in the direction of arrow of corresponding numbering sector on this groups of subchannels among Fig. 5.The division of Fig. 4 sub-channels group can be continous way also can be discrete type.

Fig. 5 has shown according to two kinds of exemplary sub-channel group technologies of the present invention.

3. determine margin and center load ratio threshold value

Determine to divide the average margin and center load of the void cell ratio threshold value γ of the multiplexing factor of edge sub-channel frequencies _Thγ _ThValue is used to define the multiplexing factor frf of edge sub-channel frequencies of void cell _EDetermine that according to average margin and center load ratio the sub-channel frequencies multiplexing factor in edge is in order to guarantee certain frequency repeat utilization ratio, avoid reducing too much the frequency repeat utilization ratio of void cell when the edge load to be big.

4. plan the high power frequency range and the low-power frequency range of each sector

Preferential selecting sequence of edge subchannel and margin and center load ratio threshold value γ according to each sector of having planned _ThPlan the high power frequency range and the low-power frequency range of each sector.The planing method of high and low power frequency range is as follows:

1) selected integer value X makes X satisfy:

①N-3X＞0；

② $\frac{X}{N-3X}\&le;{\mathrm{\&gamma;}}_{\mathrm{th}}<\frac{X+1}{N-3(X+1)}$ Or $\frac{X}{N-3X}\&le;{\mathrm{\&gamma;}}_{\mathrm{th}}$ And N-3 (X+1)≤0

N is total number of subchannels of system in the formula.

2) according to the preferential selecting sequence of edge subchannel of each sector of having planned, X subchannel conduct high power subchannel is separately selected in the sector that is respectively three groups of different numberings, N-3X subchannel to not chosen by three numbering sectors also numbered the high power subchannel of sector as each simultaneously, and the remaining subchannel in each sector this moment then is its low-power subchannel.

Each is numbered the high power subchannel of selecting according to the method described above the sector and represents that big probability is elected to be the subchannel of edge and center subchannel by identical numbering sector in the system, and the low-power subchannel represents that then big probability is elected to be the subchannel of edge subchannel by difference numbering sector.Fig. 6 has shown that this carries out an example results of high and low power frequency range planning according to the method described above, and the discrete packets mode is adopted in the subchannel grouping among the figure.

Two, determine central user and edge customer

According to division index of determining in the initialization and division thresholding the user in each sector is divided into central user and edge customer two big classes.For example the average link carrier/interface ratio is higher than certain thresholding or and the base station between distance be decided to be the sector central user less than the user of certain thresholding, remaining user is decided to be sector-edge user.

Three, determine the center number of subchannels and the edge number of subchannels of each sector of void cell

1. determine the frequency duplex factor as one of edge subchannel

After having divided central user and edge customer, void cell calculates its average margin and center load ratio γ, when γ less than the average margin and center load ratio threshold value γ that predesignates _ThThe time, the frequency duplex factor as one frf of its edge subchannel _E=3; Otherwise frf _E=3/2.

The computing formula of γ as the formula (1), D wherein _CiThe total number of users or the total bandwidth need of central area, i sector in the expression void cell, D _EiTotal number of users or the total bandwidth need (i=1,2,3) of representing this sector-edge zone.

$\mathrm{\&gamma;}=\frac{1}{3}\&times;\underset{i=1}{\overset{3}{\mathrm{\&Sigma;}}}\frac{D_{\mathrm{Ei}}}{D_{\mathrm{Ci}}}...\left(1\right)$

2. computer center's number of subchannels and edge number of subchannels

At the frequency duplex factor as one frf that determines the edge subchannel _EAfter, each central area, sector number of subchannels N in the void cell _CAnd i sector-edge zone subchannels counted N in the void cell _EiComputational methods as follows:

$N_C^{\&prime;}=\mathrm{round}[N\&CenterDot;\frac{1}{3}\&CenterDot;\underset{i}{\mathrm{\&Sigma;}}\frac{\mathrm{\&alpha;}\&CenterDot;D_{\mathrm{Ci}}}{\mathrm{\&alpha;}\&CenterDot;D_{\mathrm{Ci}}+D_{\mathrm{Ei}}}]...\left(2\right)$

$N_{\mathrm{Ei}}^{\&prime;}=\mathrm{round}[(N-N_C^{\&prime;})\&CenterDot;\frac{D_{\mathrm{Ei}}}{\underset{i}{\mathrm{\&Sigma;}}{D}_{\mathrm{Ei}}}]...\left(3\right)$

$N_C=N-\underset{i}{\mathrm{\&Sigma;}}{N}_{\mathrm{Ei}}^{\&prime;}...\left(4\right)$

Work as frf _E=N _SThe time,

N _Ei＝N′ _Ei ...(5)

When ${\mathrm{frf}}_E=\frac{{\mathrm{<figure-callout\; id="2"\; label="N\; S"\; filenames="S2008101017517E00021.png,S2008101017517E00031.png"\; state="\{\{state\}\}">N</figure-callout>}}_S}{2}$ The time,

$N_{\mathrm{Ei}}=N_{\mathrm{Ei}}^{\&prime;}+\min \{N_{\mathrm{Ei}}^{\&prime;},\underset{j\&NotEqual;i}{\mathrm{\&Sigma;}}{N}_{\mathrm{Ej}}^{\&prime;}\}...\left(6\right)$

Round[A in the formula] represent A is carried out round, $\mathrm{\&alpha;}=\frac{{\mathrm{frf}}_C}{{\mathrm{frf}}_E}$ The expression equivalent resources occupation proportion factor, N represents the total number of subchannels of system, D _Ci, N _EiMeaning is the same.

Four, determine the edge subchannel of each sector

After the edge number of subchannels of the center number of subchannels that calculates void cell and each sector, the edge subchannel is chosen according to the preferential selecting sequence of edge subchannel of planning in advance in each sector in the void cell.Under the different multiplexing factors of edge sub-channel frequencies (3 or 3/2), the selection course of edge subchannel is different, hereinafter illustrates at frf in conjunction with example respectively _E=3 and frf _EThe selection course of=3/2 o'clock sector-edge subchannel.

1.frf _E＝3

Work as frf _E=3 o'clock, the edge number of subchannels that each sector basis calculates in the void cell was chosen the edge subchannel according to priority selecting sequence shown in Figure 4 and is got final product.

2.frf _E＝3/2

When ${\mathrm{frf}}_E=\frac{3}{2}$ The time, the selection of edge subchannel in two steps:

(1) N ' is chosen according to priority selecting sequence shown in Figure 4 in each sector _EiIndividual edge subchannel, the edge subchannel of each sector selection is mutually orthogonal in this course.

(2) remaining N is selected in each sector _Ei-N ' _EiIndividual edge subchannel, from the maximum sector of edge number of subchannels, each sector has been selected in (1) step of two other sector successively and has been chosen residue edge subchannel in the edge subchannel, chooses order and carries out according to the preferential selecting sequence of its edge subchannel (being order shown in Figure 4).

Five, determine the center subchannel of void cell

After the edge subchannel had been selected according to previously described method in three sectors in the void cell, the remaining subchannel of not chosen by three sectors was the center subchannel of this void cell.

Six, power division

After the center and peripheral subchannel has been determined in each sector, need determine the transmitted power on each subchannel.Each sector is according to the high power frequency range and the low-power frequency range of planning in advance, to the subchannel that belongs to its high power frequency range in its selected subchannel with sub-channel power upper limit P (annotate: $\stackrel{\&OverBar;}{P}=\frac{P_{\mathrm{Total}}}{N_T},$ P _TotalBe total transmitted power of base station, N _TTotal number of subchannels for system) send, the subchannel that belongs to its low-power frequency range then sends with the power less than P.Because the subchannel in the low-power frequency range represents big probability and be elected to be the subchannel of edge subchannel by difference numbering sector, therefore such power allocation scheme helps further to reduce that edge customer in the void cell is subjected to from the outer interference of this void cell.

Fig. 7 and Fig. 8 have shown that respectively certain void cell carries out the example of frequency, power programming, wherein the multiplexing factor frf of sector-edge sub-channel frequencies in Fig. 7 example according to this programme _EThe edge number of subchannels of=3, three sectors is respectively 3,4,2; Sector-edge frequency duplex factor as one frf in Fig. 8 example _EThe edge number of subchannels of=3/2, three sectors is respectively 6,8,4.

Seven, regular update

In real system, the load Distribution in the void cell is time dependent, and the center subchannel of each sector and edge subchannel distribute and need and adjust along with the variation of the load Distribution in the void cell in each void cell.Because the load Distribution changed condition is slower, can adopt long interval periodically to adjust or upgrade with the pattern of Event triggered.

When each the renewal, three sector base stations of void cell only need the mutual total number of users in central area (or total bandwidth need) D separately _CiWith the total number of users of fringe region (or total bandwidth need) D _EiFinish the edge subchannel and the selection of center subchannel of void cell then separately according to computational methods among the present invention and subchannel system of selection, promptly carry out identical calculating and selection course in the base station of three sectors, each sector is that edge and the center subchannel of selecting separately distributes power according to the high and low power frequency range of planning in advance then.

It more than is a specific embodiment of the present invention.For those skilled in the art of the present technique can realize or use institute of the present invention extracting method, above the disclosed embodiments are specifically described.To those skilled in the art, the various alter modes of these embodiment all are conspicuous, and method used in this application also can be applicable to other embodiment on the basis that does not break away from spirit of the present invention and protection range.Therefore, the present invention is not limited to the embodiment that the application provides, but the most extensive consistent with the application's disclosed method and novel features.

Claims (9)

1. method for coordinating semi-static interference based on void cell that is applicable to the OFDMA cell mobile communication systems comprises step:

The multiplexing factor frf of sub-channel frequencies of a, each central area, sector of void cell _C=1, the multiplexing factor frf of sub-channel frequencies in each sector-edge zone of void cell _EDecide frf according to the load Distribution ratio between each sector-edge and central area in the void cell _E＞1;

B, each sector center and peripheral zone subchannels frequency duplex factor as one of void cell of determining according to previous step and the load Distribution in each center and peripheral zone, sector are the center and peripheral region allocation available subchannels quantity of each sector of void cell, realize the equilibrium of void cell internal burden, computational methods are as follows:

Work as frf _E=N _SThe time, N _Ei=N _Ei'

When

The time,

N _CEach central area, sector number of subchannels of expression void cell, N _EiRepresent i sector-edge zone subchannels number in each void cell, round[A] represent A is carried out round,

The expression equivalent resources occupation proportion factor, D _CiThe total number of users or the total bandwidth need of central area, i sector in the expression void cell, D _EiTotal number of users in i sector-edge zone or total bandwidth need in the expression void cell (i=1,2 ..., N _S), N represents the total number of subchannels of system, N _SThe sector number that comprises for void cell;

C, the sector-edge number of sub-channels and the center number of sub-channels that obtain according to previous step, preferential selecting sequence according to planning in advance is that edge subchannel and center subchannel are chosen in each sector of void cell, makes fringe region uses between adjacent sectors subchannel quadrature as far as possible;

D, each sector are that its selected center and peripheral zone subchannels is distributed power according to the power allocation scheme of planning in advance;

E, according to each sector center and peripheral zone subchannels of void cell internal burden changes in distribution regular update, power distribution result, renewal process is finished by repeating abovementioned steps.

2. the method for claim 1, wherein cellular cell adopts hexagonal structure, each hexagon cellular cell is divided into three sectors according to 120 ° of sectorization forms, the antenna direction of each sector all points to the intersection of two neighbor cells, a void cell is made of three adjacent sectors that belong to three neighbor cells, and void cell is shaped as hexagon.

3. the method for claim 1, wherein the division of center, sector and fringe region is determined according to user link carrier/interface ratio (C/I) in this zone.

4. the method for claim 1, wherein the load ratio is calculated according to the user bandwidth demand percentage between zones of different.

5. the method for claim 1, wherein when the average margin and center load ratio γ of each sector of void cell less than certain threshold value γ _ThThe time, the frequency duplex factor as one frf of sector-edge subchannel _E=N _S(N _SThe sector number that comprises for void cell); When the average margin and center load ratio γ of each sector of void cell greater than threshold value γ _ThThe time, the frequency duplex factor as one of edge subchannel

6. the method for claim 1, wherein the edge and the central area subchannel system of selection of each sector is as follows in the void cell: i sector of void cell is this sector selection N according to the preferential selecting sequence of edge subchannel of planning in advance _EiIndividual edge subchannel, the subchannel quadrature of basic principle for as far as possible the adjacent sectors fringe region being used of the preferential selecting sequence planning of edge subchannel, after the edge subchannel had been selected in each sector, all were not selected as the center subchannel of the subchannel of edge subchannel as this each sector of void cell in the void cell.

7. the method for claim 1, wherein the available subchannels of each sector is divided into high and low two kinds of power frequency ranges, the high and low power frequency range of each sector was planned in advance in the starting stage, each sector gives more high-power transmission to the subchannel that belongs to its high power frequency range in its selected subchannel, the subchannel that belongs to its low-power frequency range gives smaller power and sends, and the basic principle of high and low power frequency range planning is for making each sector co-channel interference minimum that fringe region is subjected to when selecting the edge subchannel according to the priority of planning in advance as far as possible.

8. method as claimed in claim 7, wherein the preferential selecting sequence planing method of each sector-edge subchannel is as follows in the void cell that is made of 3 sectors: system's available subchannels is divided into equal-sized 3 groups of subchannels, respectively as the fringe region first preferential chooser channel group of 3 sectors of void cell, when the edge of certain sector number of subchannels surpasses the number of subchannels of its edge first preferential groups of subchannels, can be from the edge first preferential groups of subchannels of other sectors the borrow resource, the worst interference situation should appear when avoiding using to the full extent in the preferential selecting sequence arrangement of the edge subchannel of each sector in each groups of subchannels.

9. method as claimed in claim 7, wherein the planing method of the high and low power frequency range of each sector is as follows in the void cell that is made of 3 sectors:

A, selected integer value X make X satisfy:

①N-3X＞0；

2.

Or

And N-3 (X+1)≤0,

N is total number of subchannels of system in the formula, γ _ThBe the average margin and center load ratio thresholding of void cell,

B, according to the preferential selecting sequence of edge subchannel of each sector of having planned, X subchannel conduct high power subchannel is separately selected in 3 sectors that are respectively void cell, N-3X the subchannel of simultaneously will be not chosen by 3 sectors is also as the high power subchannel of each sector, and the remaining subchannel in each sector then is a low-power subchannel separately at this moment.

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