CN103580802B - A kind of multi-base station cooperative system transmission mode selects and user access method - Google Patents

Abstract

The open a kind of multi-base station cooperative system transmission mode of the present invention selects and user access method, each base station selected scheduled user measures each base station to self large scale channel strength and suffered interference power values, determine reporting channel set, feed back to corresponding home base stations, clean handling capacity is estimated by home base stations to CU, and estimate the clean handling capacity after system increases candidate's synergistic link respectively, it is iterated computing, choose the synergistic link corresponding to maximum and add system, and reject from candidate's synergistic link；The n that iterates takes turns, if n-th take turns iteration after clean handling capacity take turns more than the n-th 1, and without candidate's synergistic link, then the system after iteration of taking turns n-th accesses and transmission mode selection result as scheduled user；Otherwise, the system after iteration of taking turns the n-th 1 accesses and transmission mode selection result as scheduled user；The present invention effectively solves multi-user conflict problem, selects the suitableeest access base station and transmission mode for user, the spectrum efficiency of cellular system is substantially improved.

Description

A kind of multi-base station cooperative system transmission mode selects and user access method

Technical field

The invention belongs to wireless communication field, be mainly directed towards multi-base station cooperative system, be specifically related to a kind of multi-base station cooperative The transmission mode selection of customer-centric and user access method in system.

Background technology

Multi-base station cooperative, or referred to as coordinate multipoint (CoMP, Coordinated Multi-Point) transmission technology passes through base Between standing, cooperation eliminates presence of intercell interference and the spectrum efficiency of cellular network can be substantially improved.In the actual deployment of CoMP system, In view of implementation complexity and overhead (as trained expense and other signaling consumptions produced by channel information for obtaining Deng) restriction, cooperation is carried out in being typically only capable to be limited in the cooperative cluster of several base stations composition.For existing static cooperation bunch Dividing, cooperative cluster is static configuration and mutual no overlap, causes the user being positioned at cooperative cluster edge by outside by strong bunch Interference, governs the spectrum efficiency of system.Disturb between cooperative cluster to weaken, it may be considered that the dynamic clustering of customer-centric Mode, i.e. according to the channel conditions of user to neighbouring multiple base stations, if being advantageously selected for promoting the butt of this user communication quality Stand and form a cooperative cluster, this user of collaboration services.Owing to different users may need different sub-clustering results, a base station Often adhere to multiple different cooperative cluster separately, and the service ability of base station is limited, which results in user's access interference problem.Additionally, Considering when the affecting of factor such as the overhead that brings of cooperation between base stations and non-ideal communication channel information, all users are adopted The best by systematic function during cooperation transmission pattern, even not as non-cooperating system.Therefore, in actual cooperative system, need to examine Consider overhead and the impact of non-ideal communication channel information, transmission mode selection and user are accessed co-design, thus fully Play the potential of cooperative system.

Summary of the invention

In order to solve the problems referred to above, the present invention proposes many base stations association of customer-centric in a kind of multi-base station cooperative system Make transmission mode selection and user access method, make multi-base station cooperative system can open according to subscriber channel situation, current system Pin and the Non Ideal Degree of channel information, select cooperation transmission pattern or non-cooperating transmission mode for each user adaptively (in cooperation transmission pattern, scheduled user not only accesses main serving BS and also accesses cooperative base station, and the cooperation base of this user Stand in the interference as far as possible avoiding this user when carrying out downlink transfer；And in non-cooperating transmission mode, scheduled user only connects Becoming owner of serving BS, scheduled user also can be subject to while receiving the useful signal that the main serving BS self accessed is sent To from the interference of remaining base station) and the main serving BS that accesses and cooperative base station so that multi-base station cooperative system is actual Descending clean handling capacity is the biggest.

A kind of multi-base station cooperative system transmission mode selects and user access method, is realized by following step:

Step 1: each user to be serviced chooses the strongest base station of self large scale channel energy as home base stations.

Step 2: base station BS_bSelect 0 to T user to be serviced as scheduled user's (scheduling number of users of each base station Specific amounts can be different)；B represents base station sequence number, b=1,2,3 ..., N, N be total number of base in multi-base station cooperative system；T is The filled antenna amount in each base station；If N number of base station scheduled M user altogether, represent scheduled user's sequence number with u, u=1,2, 3 ..., M, and the user being scheduled by u is expressed as MS_u.If MS_uCorresponding home base stations serial number b_u, then MS_uCorresponding Home base stations be expressed as, and willAs MS_uMain serving BS,With MS_uBetween communication link be main clothes Business link.

Step 3: scheduled user MS_uMeasure whole base station large scale channel strength α to self_b,u={ α_1,u,α_2,u, α_3,u,......,α_N,u, α_b,uFor BS_bTo MS_uLarge scale channel.

Step 4: scheduled user MS_uDetermine reporting channel set.

Step 5: scheduled user MS_uMeasure respective experienced interference performance number I_u。

Step 6: scheduled user MS_uThe reporting channel set A that will be obtained in step 4 by up-link_uAnd step 5 In the scheduled user MS that obtains_uSuffered interference power values I_uFeed back to user MS_uCorresponding home base stations。

Step 7: scheduled user MS_uCorresponding home base stationsThe reporting channel set A that will collect_uAnd adjusted Degree user MS_uSuffered interference power values is by Backbone Transport to CU.

Step 8:CU is according to the reporting channel set A received_uAnd scheduled user MS_uSuffered interference power values I_uFor Scheduled user MS_uSelect transmission mode and access cooperative base station, particularly as follows:

(1) CU is according to the reporting channel set A received_uAnd scheduled user MS_uSuffered interference power values I_u, estimation When whole scheduled users all use non-cooperating transmission mode, (in non-cooperating transmission mode, scheduled user only accesses main clothes Business base station, scheduled user also suffer from while receiving the useful signal that the main serving BS that self accessed is sent from The interference of remaining base station) time, the clean handling capacity of multi-base station cooperative system, and willInitial as multi-base station cooperative system Clean handling capacity.

(2) if the large scale channel on a link at CU end it is known that i.e. large scale channel on this link belongs to A_u, Then this link is candidate's synergistic link；Making candidate's synergistic link in the present invention is W bar, and every synergistic link is expressed as H_i, i is Synergistic link number, i=1,2,3 ..., W, then constituted candidate's synergistic link collection by W bar candidate's synergistic link and be combined into U={H₁, H₂,H₃,......,H_W}；Thus, it is iterated computing by CU, obtains choosing each association respectively in candidate synergistic link set U Make link and add the clean handling capacity to current multi-base station cooperative system(i.e. CU is the most only by H₁Add multi-base station cooperative system After obtainThe most only by H₂Obtain after adding multi-base station cooperative systemBy that analogy, the most only by H_WAdd many base stations Obtain after cooperative system).

ChooseMiddle maximumCorresponding synergistic link H_iAdd current multi-base station cooperative system, simultaneously will cooperation Link H_iReject from candidate synergistic link set U, after completing to first round interative computation, enter step 3.

(3) the clean handling capacity of multi-base station cooperative system after interative computation is taken turns to n-th by CUAfter taking turns iteration with (n-1)th The clean handling capacity of systemMagnitude relationship:

If i.Time, then determine whether whether candidate synergistic link set U is empty set；If nonvoid set, then Return and perform step (2), again carry out next round iteration；If empty set, then enter step 9；

If ii.Iteration terminates, and enters step 10；

In step i and ii, as n=1,The original net handling capacity being

Step 9: the multi-base station cooperative system after iteration of taking turns n-th is as final scheduled user MS_uAccess and transmission Model selection result.

Step 10: multi-base station cooperative system when taking turns iteration using (n-1)th is as final scheduled user MS_uAccess and pass Defeated model selection result.

In above-mentioned steps 9 and step 10, by matrix S=[s_ub]_K×NRepresent main service link opening relationships；Wherein, S is There is the 0-1 matrix of K row N row, s_ubFor the element of u row b row in matrix S；And if base station BS_bFor scheduled user MS_uMaster Serving BS, then s_ub=1；Otherwise, s_ub=0.

By Matrix C=[c_ub]_K×NRepresent the opening relationships of synergistic link；Wherein, C is the 0-1 matrix with K row N row, c_ubFor the element of u row b row in Matrix C；And if base station BS_bIt is scheduled user MS_uCooperative base station, i.e. BS_bWith MS_uBetween deposit At synergistic link, then c_ub=1；Otherwise, c_ub=0.

Thus, scheduled user MS_uCooperative base station set is D_u=b | c_ub=1}, access base station set is E_u=D_u ∪{b_u}。

It is an advantage of the current invention that:

1, the inventive method accesses problem for the user in multi-base station cooperative system, in efficiently solving and with user being Multi-user conflict problem in heart mode, and with transmission mode selection co-design, can be according to the situation of each user, for it Select the suitableeest access base station and transmission mode such that it is able to the spectrum efficiency of cellular system is substantially improved；

2, the inventive method has taken into full account (the training expense and non-ideal of non-ideal factor in real system when design Channel information) impact on downlink transfer, and propose based on non-ideal communication channel information for this and there is expense perception characteristic Solution, it is possible to according to current system expense and the Non Ideal Degree of channel information, select suitably to transmit for user Pattern, the clean loss of throughput making system is the least, more has practical value；

3, the inventive method is merely with the large-scale channel information of user and interference power values, and they are all statistics letters Breath, changes slower；Therefore, be not required to when real system runs to switch frequently for each user access base station and Transmission mode, can be greatly reduced the deployment of the handover overhead of system, more conducively real system.

Accompanying drawing explanation

Fig. 1 is the inventive method overall flow figure；

Fig. 2 is multi-base station cooperative system schematic；

Fig. 3 is that in the inventive method, user accesses and transmission mode selection result schematic diagram.

Detailed description of the invention

The present invention is mainly directed towards multi-base station cooperative system: it is to be serviced with several that multi-base station cooperative system comprises N number of base station User, represents base station sequence number with b, b=1,2,3 ..., N, and the b base station table is shown as BS_b, the filled antenna number in each base station Amount is T root, launches power and is P.Each base station is connected to center processing unit CU by backbone network.The present invention is by following step Suddenly the many base station transmission mode realizing customer-centric select and user access method, as shown in Figure 1:

Step 1: each user to be serviced chooses the strongest base station of self large scale channel energy as home base stations.

Step 2: base station BS_bSelect 0 to T user to be serviced as scheduled user's (scheduling number of users of each base station Specific amounts can be different)；If N number of base station scheduled M user altogether, represent scheduled user's sequence number with u, u=1,2,3 ..., M, and the user that u is scheduled is expressed as MS_u.If MS_uCorresponding home base stations serial number b_u, then MS_uThis corresponding ground Station is expressed as, and willAs MS_uMain serving BS,With MS_uBetween communication link be main service link.

Step 3: scheduled user MS_uMeasure whole base station large scale channel strength α to self_b,u={ α_1,u,α_2,u, α_3,u,......,α_N,u, α_b,uFor BS_bTo MS_uLarge scale channel.

Step 4: scheduled user MS_uDetermine reporting channel set；

Reporting channel set can be determined by under type 1 or mode 2:

Mode 1: make scheduled user MS_uReporting channel set sizes be equal to F, 0 ＜ F≤N；Then in selecting step 3 The α obtained_b,uFront F the large scale channel A that middle large scale channel strength is the strongest_u；

Mode 2: make scheduled user MS_uReporting channel set sizes depend on that the large scale channel phase of self is arrived in base station To intensity, then scheduled user MS_uReporting channel set A_uFor:

$A_u=\left\{{\mathrm{\α}}_{b,u}\right|\frac{{\mathrm{\α}}_{b,u}^2}{{\mathrm{\α}}_{b_u,u}^2}>\mathrm{\θ}\}---\left(1\right)$

In formula (1),For MS_uHome base stationsTo MS_uLarge scale channel, θ is feedback threshold, 0 ＜ θ≤1.

Step 5: scheduled user MS_uMeasure respective experienced interference performance number I_u。

Step 6: scheduled user MS_uThe reporting channel set A that will be obtained in step 4 by up-link_uAnd step 5 In the scheduled user MS that obtains_uSuffered interference power values I_uFeed back to user MS_uCorresponding home base stations。

Step 7: scheduled user MS_uCorresponding home base stationsThe reporting channel set A that will collect_uAnd adjusted Degree user MS_uSuffered interference power values is by Backbone Transport to CU.

Step 8:CU is according to the reporting channel set A received_uAnd scheduled user MS_uSuffered interference power values I_uFor Scheduled user MS_uSelect transmission mode and access cooperative base station, particularly as follows:

(1) CU is according to the reporting channel set A received_uAnd scheduled user MS_uSuffered interference power values I_u, estimation When whole scheduled users all use non-cooperating transmission mode, the clean handling capacity of multi-base station cooperative systemAnd willAs The original net handling capacity of multi-base station cooperative system.

(2) if the large scale channel on a link at CU end it is known that i.e. large scale channel on this link belongs to A_u, Then this link is candidate's synergistic link；Making candidate's synergistic link in the present invention is W bar, and every synergistic link is expressed as H_i, i is Synergistic link number, i=1,2,3 ..., W, then constituted candidate's synergistic link collection by W bar candidate's synergistic link and be combined into U={H₁, H₂,H₃,......,H_W}；Thus, it is iterated computing by CU, obtains choosing each association respectively in candidate synergistic link set U Make link and add the clean handling capacity to current multi-base station cooperative system(i.e. CU is the most only by H₁Add multi-base station cooperative system After obtainThe most only by H₂Obtain after adding multi-base station cooperative systemBy that analogy, the most only by H_WAdd many base stations association Obtain after making system).

ChooseMiddle maximumCorresponding synergistic link H_iAdd current multi-base station cooperative system, simultaneously will cooperation Link H_iReject from candidate synergistic link set U, after completing to first round interative computation, enter step 3；

(3) the clean handling capacity of multi-base station cooperative system after interative computation is taken turns to n-th by CUAfter taking turns iteration with (n-1)th The clean handling capacity of systemMagnitude relationship:

If i.Time, then determine whether whether candidate synergistic link set U is empty set；If nonvoid set, then Return and perform step (2), again carry out next round iteration；If empty set, then enter step 9；

If ii.Iteration terminates, and enters step 10；

In step i and ii, as n=1,The original net handling capacity being。

In above-mentioned steps 8, the clean handling capacity evaluation method of multi-base station cooperative system is by CU:

By matrix S=[s_ub]_K×NRepresent the main service link opening relationships in step 2；Wherein, S is for having K row N row 0-1 matrix, s_ubFor the element of u row b row in matrix S；And if base station BS_bFor scheduled user MS_uMain serving BS, then s_ub=1；Otherwise, s_ub=0.

By Matrix C=[c_ub]_K×NRepresent the opening relationships of synergistic link in step 8；Wherein, C is to have K row N row 0-1 matrix, c_ubFor the element of u row b row in Matrix C；And if base station BS_bIt is scheduled user MS_uCooperative base station, i.e. BS_bWith MS_uBetween there is synergistic link, then c_ub=1；Otherwise, c_ub=0.

Thus, by scheduled user MS_uCooperative base station set is designated as D_u=b | c_ub=1}, access base station set (i.e. cooperates Bunch) it is designated as E_u=D_u∪{b_u}.Such as: if the 3rd row element of matrix B is [0,1,0,1,1,0,0], the 3rd row element of matrix S For [0,0,1,0,0,0,0], then user MS₃Main serving BS is BS₃, cooperative base station set D_u={BS₂,BS₄,BS₅, access base Stand set E_u={BS₂,BS₃,BS₄,BS₅}.Work as D_uDuring for empty set, namely E_u={ b_uTime, scheduled user MS_uDo not cooperate base Stand, then scheduled user MS_uUse non-cooperating transmission mode.

Then CU is by the clean handling capacity of following formula estimation multi-base station cooperative system:

$\stackrel{\‾}{R}=(1-\mathrm{YTv})\underset{u=1}{\overset{K}{\mathrm{\Σ}}}{\log }_2(1+{\stackrel{\‾}{\mathrm{\γ}}}_u)---\left(2\right)$

In formula (1),For CU to scheduled user MS_uReceive Signal to Interference plus Noise Ratio estimation；For FDD(FDD) be For system, v is the ratio that the training expense of every antenna takies family down time-frequency resource, and its value is configured with concrete system Close.d_bFor with BS_bBelong to the base station number of identical cooperative cluster together；k_bIt is to all base stations According to d_bDescending after sequence number；

Such as: if

$S+C=\left(\begin{array}{ccccccc}1& 0& 0& 1& 1& 0& 0\\ 1& 1& 0& 0& 0& 0& 1\\ 1& 1& 1& 0& 0& 0& 0\\ 1& 0& 0& 1& 1& 0& 0\\ 0& 0& 0& 0& 1& 0& 0\\ 1& 0& 0& 0& 1& 1& 0\\ 0& 0& 0& 0& 0& 1& 1\end{array}\right)$

Then have:

Drawn by following formula:

${\stackrel{\‾}{\mathrm{\γ}}}_u=\frac{\frac{{\mathrm{\α}}_{b_u,u}^2\mathrm{PT}}{Q_u}\left\{\right[1-2^B\mathrm{\β}(2^B,\frac{T}{T-1})]\frac{T-L_u}{T}+2^B\mathrm{\β}(2^B,\frac{T}{T-1})\frac{L_u}{T(T-1)}\}}{2^B\mathrm{\β}(2^B,\frac{T}{T-1})\frac{\mathrm{PT}}{T-1}(\frac{Q_u-1}{Q_u}{\mathrm{\α}}_{b_u,u}^2+\underset{j\∈E_u,j\≠b_u}{\mathrm{\Σ}}{\mathrm{\α}}_{j,u}^2)+I_u-\underset{j\∈E_u,j\≠b_u}{\mathrm{\Σ}}{\mathrm{P\α}}_{j,u}^2+{\mathrm{\σ}}^2}---\left(3\right)$

In formula (3), B is the quantizing bit number of channel codebook, σ²For user's receiving terminal noise power, (x y) is Beta letter to β Number, $\mathrm{\β}(x,y)={\∫}_0^{\∞}{v}^{x-1}{(1-v)}^{y-1}\mathrm{dv};Q_u={\mathrm{\Σ}}_{j=1}^K{s}_{{\mathrm{jb}}_u},L_u={\mathrm{\Σ}}_{j=1}^K(s_{{\mathrm{jb}}_u}+c_{{\mathrm{jb}}_u})-1.$

For TDD(time division duplex) system, v is the ratio that the training expense of every antenna takies the total running time-frequency resource of family up-downgoing Example, its value is relevant with concrete system configuration.d_uFor with scheduled user MS_uAccess The number of users of same base, k_uFor user according to d_uDescending after sequence number；

Such as: if

$S+C=\left(\begin{array}{ccccccc}1& 0& 0& 1& 1& 0& 0\\ 1& 1& 0& 0& 0& 0& 1\\ 1& 1& 1& 0& 0& 0& 0\\ 1& 0& 0& 1& 1& 0& 0\\ 0& 0& 0& 0& 1& 0& 0\\ 1& 0& 0& 0& 1& 1& 0\\ 0& 0& 0& 0& 0& 1& 1\end{array}\right)$

Then have:

Drawn by following formula:

${\stackrel{\‾}{\mathrm{\γ}}}_u=\frac{\frac{{\mathrm{\α}}_{b_u,u}^2\mathrm{PT}}{Q_u}[\frac{{\mathrm{\ρ}}^2}{1+{\mathrm{\ρ}}^2}(T-L_u-1)+1]}{\frac{1}{1+{\mathrm{\ρ}}^2}\frac{\mathrm{TP}}{T-1}(\frac{Q_u-1}{Q_u}{\mathrm{\α}}_{b_u,u}^2+\underset{j\∈E_u,j\≠b_u}{\mathrm{\Σ}}{\mathrm{\α}}_{j,u}^2)+I_u-\underset{j\∈E_u,j\≠b_u}{\mathrm{\Σ}}{\mathrm{P\α}}_{j,u}^2+{\mathrm{\σ}}^2}---\left(4\right)$

In formula (4), $Q_u={\mathrm{\Σ}}_{j=1}^K{s}_{{\mathrm{jb}}_u},L_u={\mathrm{\Σ}}_{j=1}^K(s_{{\mathrm{jb}}_u}+c_{{\mathrm{jb}}_u})-1,$ ρ is the evaluated error of channel, with training sequence Row design and real system relating to parameters.

Step 9: the multi-base station cooperative system after iteration of taking turns n-th is as final scheduled user MS_uAccess and transmission Model selection result.

Step 10: multi-base station cooperative system when taking turns iteration using (n-1)th is as final scheduled user MS_uAccess and pass Defeated model selection result.

In above-mentioned steps 9 and step 10, scheduled user MS_uCooperative base station set is D_u=b | c_ub=1}, accesses base Set of standing is E_u=D_u∪{b_u}。

Implement example, as in figure 2 it is shown, multi-base station cooperative system is FDD(FDD) working method, comprise 7 base stations BS₁,BS₂,BS₃,......,BS₇, all base stations are connected to 1 CU by backbone network.Each base station is equipped with T=4 root antenna, often The training expense of root antenna takies 0.75% user's down time-frequency resource, i.e. v=0.75%, and base station transmitting power is P=46dBm. Having 7 communities, each radius of society 250m, all there are 2 users to be serviced each community, user the most to be serviced totally 14, respectively For WMS₁,WMS₂,WMS₃,......,WMS₁₄；User's receiving terminal noise power is σ²=-95dBm, the quantization bit of channel codebook Number is B=8bit.

Step 1: each user to be serviced chooses the strongest base station of its channel energy as home base stations, result such as table 1 institute Show:

Table 1: the home base stations corresponding to user to be serviced

Step 2: 1 user is dispatched respectively as scheduled user in each base station, the main serving BS of the most each scheduled user, As shown in table 2 and Fig. 2:

Table 2: the main serving BS corresponding to scheduled user

Then representing main service link opening relationships by 0-1 matrix S, the value of matrix S is as follows:

$S=\left(\begin{array}{ccccccc}1& 0& 0& 0& 0& 0& 0\\ 0& 1& 0& 0& 0& 0& 0\\ 0& 0& 1& 0& 0& 0& 0\\ 0& 0& 0& 1& 0& 0& 0\\ 0& 0& 0& 0& 1& 0& 0\\ 0& 0& 0& 0& 0& 1& 0\\ 0& 0& 0& 0& 0& 0& 1\end{array}\right).$

Step 3: each scheduled user measures each base station large scale channel strength to self；

Step 4: each scheduled user MS_uDetermine reporting channel set；

In this example, the reporting channel set shown in employing mode 1 determines method, and makes F=3, i.e. each use that is scheduled Using front 3 big large scale channels the strongest for the large scale channel strength obtained in step 3 as reporting channel set, such as table 3 Shown in:

Table 3: the reporting channel set corresponding to scheduled user

Step 5: each scheduled user measures respective experienced interference performance number, as shown in table 4.

Scheduled user MSu	MS1	MS2	MS3	MS4	MS5	MS6	MS7
								Jamming power Iu(W)	9.63	5.26	8.32	7.68	2.63	11.2	6.63

Table 4: the interference power values corresponding to scheduled user

Step 6: each scheduled user feeds back, to self corresponding home base stations, the reporting channel set each obtained And interference power values suffered by self.

Step 7: the home base stations corresponding to each scheduled user is by the reporting channel set collected and interference merit Rate value is by Backbone Transport to CU.

Step 8:CU, according to the reporting channel set received and interference power values, selects to pass for each scheduled user Defeated pattern and access cooperative base station, particularly as follows:

(1) CU all adopts as whole scheduled users according to the reporting channel set received and interference power values, estimation During by non-cooperating transmission mode, the clean handling capacity of multi-base station cooperative systemAnd willInitial as multi-base station cooperative system Clean handling capacity.

Represented the opening relationships of synergistic link by 0-1 Matrix C, initialize Matrix C, make C⁽⁰⁾=0, according to formula (2), formula (3) obtain ${\stackrel{\‾}{R}}^{\left(0\right)}=20.967\mathrm{bit}/s/\mathrm{Hz}.$

(2) CU carries out first round iteration, and the synergistic link in synergistic link Candidate Set is added separately to current many base stations In cooperative system, i.e. to Matrix C⁽⁰⁾Middle one 1 element of interpolation respectively, obtains C⁽¹⁾, each C is estimated respectively by CU⁽¹⁾Many bases The clean handling capacity of cooperative system of standing, result of calculation is as shown in table 5:

Newly add 1 element	Clean handling capacity (bit/s/Hz)	Newly add 1 element	Clean handling capacity (bit/s/Hz)
				c15=1	20.9215	c41=1	20.8245
c16=1	21.0197	c56=1	21.6093
				c23=1	21.6951	c51=1	20.6675
c21=1	21.6902	c61=1	21.5145
				c31=1	21.2436	c67=1	20.6314
c32=1	20.7945	c76=1	21.6572
				c45=1	21.3021	c71=1	20.7466

Table 5: multi-base station cooperative system net handling capacity after first round iteration

Obtained by upper table: multi-base station cooperative system net handling capacity is to the maximumThen multi-base station cooperative system The synergistic link that newly adds during clean handling capacity maximum is BS₃→MS₂, the synergistic link of its correspondence is added to current multi-base station cooperative System, rejects from candidate's synergistic link simultaneously, finally gives:

$C^{\left(1\right)}=\left(\begin{array}{ccccccc}0& 0& 0& 0& 0& 0& 0\\ 0& 0& 1& 0& 0& 0& 0\\ 0& 0& 0& 0& 0& 0& 0\\ 0& 0& 0& 0& 0& 0& 0\\ 0& 0& 0& 0& 0& 0& 0\\ 0& 0& 0& 0& 0& 0& 0\\ 0& 0& 0& 0& 0& 0& 0\end{array}\right)$

Due toThen return (2nd) step in step 8 and continue iteration；Now by current cooperative link Candidate Set Synergistic link be added separately in current multi-base station cooperative system, i.e. to Matrix C⁽¹⁾Middle one 1 element of interpolation respectively, obtains C⁽²⁾, each C is estimated respectively by CU⁽²⁾Multi-base station cooperative system net handling capacity, result of calculation is as shown in table 6:

Multi-base station cooperative system net handling capacity after iteration taken turns by table 6: the second

Obtained by upper table: multi-base station cooperative system net handling capacity is to the maximumThen multi-base station cooperative system The synergistic link that newly adds during clean handling capacity maximum is BS₆→MS₇, the synergistic link of its correspondence is added to current multi-base station cooperative System, rejects from candidate's synergistic link simultaneously, finally gives:

$C^{\left(2\right)}=\left(\begin{array}{ccccccc}0& 0& 0& 0& 0& 0& 0\\ 0& 0& 1& 0& 0& 0& 0\\ 0& 0& 0& 0& 0& 0& 0\\ 0& 0& 0& 0& 0& 0& 0\\ 0& 0& 0& 0& 0& 0& 0\\ 0& 0& 0& 0& 0& 0& 0\\ 0& 0& 0& 0& 0& 1& 0\end{array}\right)$

Due toThen return step 8 (2nd) step and continue iteration, so iterate, as shown in table 7, obtain:

Table 7: nine take turns iteration after multi-base station cooperative system net handling capacity and newly add synergistic link as can be seen here,Now terminating iteration, the final value of Matrix C is as follows:

$C=C^{\left(8\right)}=\left(\begin{array}{ccccccc}0& 0& 0& 0& 0& 0& 0\\ 1& 0& 1& 0& 0& 0& 0\\ 1& 1& 0& 0& 0& 0& 0\\ 0& 0& 0& 0& 1& 0& 0\\ 0& 0& 0& 0& 0& 1& 0\\ 1& 0& 0& 0& 0& 0& 0\\ 0& 0& 0& 0& 0& 1& 0\end{array}\right)$

Thus, according to matrix S and C, obtain final user and access and transmission mode selection result, such as table 8 and Fig. 3 institute Show；In Fig. 3: zero represents user, and △ represents base station.

Table 8: user accesses and transmission mode selection result

Claims (4)

1. a multi-base station cooperative system transmission mode selects and user access method, it is characterised in that: real by following step Existing:

Step 1: each user to be serviced chooses the strongest base station of self large scale channel energy as home base stations；

Step 2: base station BS_bSelect 0 to T user to be serviced as scheduled user；B represents base station sequence number, b=1,2, 3 ..., N, N be total number of base in multi-base station cooperative system；T is filled antenna amount by each base station；If N number of base station is dispatched altogether M user, represents scheduled user sequence number with u, u=1,2,3 ..., M, and the user that u is scheduled is expressed as MS_uIf MS_uCorresponding home base stations serial number b_u, then MS_uCorresponding home base stations is expressed asAnd willAs MS_u's Main serving BS,With MS_uBetween communication link be main service link；

Step 3: scheduled user MS_uMeasure whole base station large scale channel strength α to self_b,u={ α_1,u,α_2,u, α_3,u,......,α_N,u, α_b,uFor BS_bTo MS_uLarge scale channel；

Step 4: scheduled user MS_uDetermine reporting channel set；

Step 5: scheduled user MS_uMeasure respective experienced interference performance number I_u；

Step 6: scheduled user MS_uThe reporting channel set A that will be obtained in step 4 by up-link_uAnd in step 5 The scheduled user MS arrived_uSuffered interference power values I_uFeed back to user MS_uCorresponding home base stations

Step 7: scheduled user MS_uCorresponding home base stationsThe reporting channel set A that will collect_uAnd scheduled user MS_uSuffered interference power values passes through Backbone Transport to center processing unit；

Step 8: center processing unit is according to the reporting channel set A received_uAnd scheduled user MS_uSuffered jamming power Value I_uFor scheduled user MS_uSelect transmission mode and access cooperative base station, particularly as follows:

(1) center processing unit is according to the reporting channel set A received_uAnd scheduled user MS_uSuffered interference power values I_u, estimate when whole scheduled users all use non-cooperating transmission mode, the clean handling capacity of multi-base station cooperative systemAnd willOriginal net handling capacity as multi-base station cooperative system；

(2) if the large scale channel on a link at center processing unit end it is known that i.e. large scale channel on this link Belong to A_u, then this link is candidate's synergistic link；Making candidate's synergistic link in the present invention is W bar, and every synergistic link represents For H_i, i be synergistic link numbering, i=1,2,3 ..., W, then constituted candidate's synergistic link set by W bar candidate's synergistic link For U={H₁,H₂,H₃,......,H_W}；Thus, it is iterated computing by center processing unit, obtains at candidate's synergistic link Set U chooses each synergistic link respectively and adds the clean handling capacity to current multi-base station cooperative system

ChooseMiddle maximumCorresponding synergistic link H_iAdd current multi-base station cooperative system, simultaneously by synergistic link H_iReject from candidate synergistic link set U, after completing to first round interative computation, enter step 3；

(3) the clean handling capacity of multi-base station cooperative system after interative computation is taken turns to n-th by center processing unitTake turns with (n-1)th The clean handling capacity of system after iterationMagnitude relationship:

If i.Time, then determine whether whether candidate synergistic link set U is empty set；If nonvoid set, then return Perform step (2), again carry out next round iteration；If empty set, then enter step 9；

If ii.Iteration terminates, and enters step 10；

In step i and ii, as n=1,The original net handling capacity being

Step 9: the multi-base station cooperative system after iteration of taking turns n-th is as final scheduled user MS_uAccess and transmission mode is selected Select result；

Step 10: multi-base station cooperative system when taking turns iteration using (n-1)th is as final scheduled user MS_uAccess and transmission mould Formula selects result；

Thus, by matrix S=[s_ub]_K×NRepresent the main service link opening relationships in step 2；Wherein, S is for having K row N row 0-1 matrix, s_ubFor the element of u row b row in matrix S；And if base station BS_bFor scheduled user MS_uMain serving BS, then s_ub=1；Otherwise, s_ub=0；

By Matrix C=[c_ub]_K×NRepresent the opening relationships of synergistic link in step 8；Wherein, C is the 0-1 square with K row N row Battle array, c_ubFor the element of u row b row in Matrix C；And if base station BS_bIt is scheduled user MS_uCooperative base station, i.e. BS_bWith MS_uBetween There is synergistic link, then c_ub=1；Otherwise, c_ub=0；

Thus, in step 9 and step 10, scheduled user MS_uCooperative base station set is designated as D_u=b | c_ub=1}, access base station collection Conjunction is designated as E_u=D_u∪{b_u}。

2. a kind of multi-base station cooperative system transmission mode selects and user access method, it is characterised in that: In described step 4, scheduled user MS_uDetermine reporting channel set, be accomplished by:

Make scheduled user MS_uThe signal set size that reports be equal to F, 0 ＜ F≤N；The α then obtained in selecting step 3_b,uIn Front F the large scale channel A that large scale channel strength is the strongest_u。

3. a kind of multi-base station cooperative system transmission mode selects and user access method, it is characterised in that: In described step 4, scheduled user MS_uDetermine reporting channel set, be accomplished by:

Make scheduled user MS_uReport signal set size to depend on the large scale channel relative intensity of self is arrived in base station, then by Scheduling user MS_uReporting channel set A_uFor:

In formula (1),For MS_uHome base stationsTo MS_uLarge scale channel, θ is feedback threshold, 0 ＜ θ≤1.

4. a kind of multi-base station cooperative system transmission mode selects and user access method, it is characterised in that: In described step 8, the clean handling capacity evaluation method of multi-base station cooperative system is by center processing unit:

In formula (1),Centered by processing unit to scheduled user MS_uReceive Signal to Interference plus Noise Ratio estimation；

For FDD system, v is the ratio that the training expense of every antenna takies family down time-frequency resource；

d_bFor with BS_bBelong to the base station number of identical cooperative cluster together；k_bIt is to all bases Stand according to d_bDescending after sequence number；

Drawn by following formula:

In formula (2), B is the quantizing bit number of channel codebook；P is the transmitting power of each base station；σ²Receive for user End noise power；β (x, y) is Beta function,

For TDD (time division duplex) system, v is the ratio that the training expense of every antenna takies the total running time-frequency resource of family up-downgoing；d_uFor with scheduled user MS_uAccess the number of users of same base, k_uFor user according to d_uDescending after sequence number；

Drawn by following formula:

In formula (3), ρ is the evaluated error of channel.