CN102196585A - Method for determining downlink transmission mode of coordinated multi-point transmission - Google Patents

Abstract

The invention provides a method for determining the downlink transmission mode of a coordinated multi-point transmission. The method comprises the following steps of: calculating the signal-to-interference and noise ratios of each user to be scheduled in non-coordinated multi-point transmission; dividing all the users to be scheduled into edge users and central users according to the signal-to-interference and noise ratios or the current locations of the users; calculating the Auij of each user uij to be scheduled; determining orthogonal threshold values muuij of each user uij to be scheduled according to muuij=max{delta, Auij}, wherein SINR<CoMP>uij:thetauij=1 represents the signal-to-interference and noise ratio of the user uij adopting a coordinated multi-point transmission mode and completely orthogonal with a paired user, and delta is a preset orthogonal threshold regulation parameter; for each edge user, determining the paired user of the edge user according to the principle of ensuring orthogonal characteristics among a plurality of simultaneously served users are higher than own orthogonal threshold values, and determining that the edge user and the paired user thereof adopt the coordinated multi-point transmission mode, and serving the edge user and the paired user thereof; and determining that the un-served central user adopts a non-coordinated multi-point transmission mode, and serving the un-served central user. By the method, system edge performance can be effectively improved, and simultaneously, system center performance is ensured.

Description

A kind of definite method of collaborative multicast communication downlink transmission mode

Technical field

The present invention relates to the dispatching technique in the mobile communication system, particularly relate to after introducing collaborative multicast communication (CoMP) technology in the system definite method of user's downlink transmission mode.

Background technology

CoMP is one of important technology in the long evolving system (LTE), and its core concept is by multipoint cooperative, constitutes virtual multiple-input and multiple-output (VMIMO), thereby can effectively solve presence of intercell interference, promotes cell edge and average behavior.But the employing of CoMP technology needs more downlink signaling, mainly is that the DMRS letter is modern, and these signalings will take the descending channel resource that is used for transfer of data.

Take all factors into consideration the performance gain of CoMP and the signaling consumption that CoMP brings, for the certain user, it can be balanced out by demodulated reference signal (DMRS) signaling consumption that CoMP causes because of the performance gain that CoMP brings, even these users' the situation of equivalent CoMP performance gain for bearing can occur.Therefore, in order to realize better system performance, need reasonably divide CoMP user and non-CoMP user.

At present, some definite methods about differentiation CoMP user and non-CoMP user's downlink transmission mode have been proposed.Its basic ideas are unanimous on the whole: the user of poor-performing and is transmitted according to the CoMP-SU mode these users as CoMP user during with non-CoMP, and this CoMP-SU mode is the mode that a plurality of base stations are served a user simultaneously.

Said method can improve the edge performance of system, and still, the transmission means of CoMP-SU can only be served a user at every turn, therefore, can prolong whole scheduling time, thereby influences the center performance of system.

Summary of the invention

In view of this, main purpose of the present invention is to provide a kind of definite method of collaborative multicast communication downlink transmission mode formula, and this method can guarantee the center performance of system when effectively improving the system edges performance.

In order to achieve the above object, the technical scheme of the present invention's proposition is:

A kind of definite method of collaborative multicast communication downlink transmission mode, this method may further comprise the steps:

A, the Signal to Interference plus Noise Ratio when calculating each non-collaborative multicast communication for the treatment of dispatched users; Current location according to described Signal to Interference plus Noise Ratio or user is divided into two classes with remaining dispatched users, and wherein, a class is an edge customer, and another kind of is central user, and the described Signal to Interference plus Noise Ratio of described edge customer is less than the described Signal to Interference plus Noise Ratio of described central user;

According to $A_{u_{\mathrm{ij}}}={{\mathrm{SINR}}_{u_{\mathrm{ij}}}^{\mathrm{CoMP}}|}_{{\mathrm{\&theta;}}_{u_{\mathrm{ij}}=1}}/{\mathrm{SINR}}_{u_{\mathrm{ij}}}^{\mathrm{NoCoMP}},$ Calculate each and treat dispatched users u _Ij

According to ${\mathrm{\&mu;}}_{u_{\mathrm{ij}}}=\max \{\&PartialD;,A_{u_{\mathrm{ij}}}\},$ Determine that each treats dispatched users u _IjThe quadrature thresholding

Wherein,

Be user u _IjAdopt collaborative multipoint transmission mode and and the Signal to Interference plus Noise Ratio during the complete quadrature of its pairing user,

Be user u _IjSignal to Interference plus Noise Ratio when adopting non-collaborative multipoint transmission mode,

For default quadrature thresholding is adjusted parameter, u _IjBe j user of i sub-district;

B, for each described edge customer, the principle that is higher than described separately quadrature thresholding according to the orthogonal property between a plurality of users that guarantee to serve is simultaneously determined the pairing user of this edge customer, determines that this edge customer and pairing user thereof adopt collaborative multipoint transmission mode and serve;

C, determine that user not serviced in the described central user adopts non-collaborative multipoint transmission mode and serves.

In sum, definite method of the collaborative multicast communication downlink transmission mode that the present invention proposes, Signal to Interference plus Noise Ratio during according to user's non-collaborative multicast communication, select the edge customer that must adopt the CoMP transmission mode, and determine the pairing user of each edge customer according to the principle of the orthogonal property between a plurality of users that guarantee to serve simultaneously, thereby can when effectively improving the system edges performance, guarantee the center performance of system.

Description of drawings

Fig. 1 is the flow chart of the embodiment of the invention one;

Fig. 2 is the flow chart of step 104 among Fig. 1;

Fig. 3 determines that with the downlink transmission mode that tradition is distinguished CoMP user and non-CoMP user the performance of method compares schematic diagram for the present invention.

Embodiment

For making the purpose, technical solutions and advantages of the present invention clearer, the present invention is described in further detail below in conjunction with the accompanying drawings and the specific embodiments.

Core concept of the present invention is: the performance of Signal to Interference plus Noise Ratio poor user when being effectively to improve non-collaborative multicast communication in view of the main effect of collaborative multicast communication, the dried less dispatched users (hereinafter being called edge customer) for the treatment of of making an uproar of letter when the present invention will select non-collaborative multicast communication, as the user that must adopt collaborative multipoint transmission mode, with the performance gain of the collaborative multicast communication of abundant acquisition, improve the edge performance of system.Simultaneously, in order to reduce whole scheduling time, the present invention will serve a plurality of users as far as possible simultaneously when each scheduling.Promptly, for each edge customer, to be higher than the principle of quadrature thresholding separately according to the orthogonal property between a plurality of users that guarantee to serve simultaneously, from remaining dispatched users, select the pairing user (i.e. the user who serves simultaneously) of this edge customer, if this edge customer has the pairing user, determine that then this edge customer and pairing user thereof adopt the mode of multi-user collaborative multicast communication; If this edge customer does not match the user, determine that then this edge customer and pairing user thereof adopt the mode of single user collaborative multicast communication.And, then adopt the mode of non-collaborative multicast communication for matching user the user except that edge user and being selected as in the remaining dispatched users.Because in the practical application, when the orthogonal property between a plurality of users of service simultaneously can be guaranteed, all user performances of carrying out the CoMP transmission must be better than all user performances of non-CoMP transmission, promptly will obtain CoMP performance gain preferably.Therefore, the present invention determines its pairing user by the principle that is higher than quadrature thresholding separately according to the orthogonal property between a plurality of users that guarantee to serve simultaneously for each edge customer, can be under the prerequisite that guarantees acquisition CoMP performance gain, the number of users that increase is engaged in the space-time sub-service, reduce the scheduling time of entire system, and then guarantee the center performance of system.

Fig. 1 is the flow chart of the embodiment of the invention one, and as shown in Figure 1, this embodiment mainly comprises:

Step 101, the Signal to Interference plus Noise Ratio when calculating each non-collaborative multicast communication for the treatment of dispatched users.

The concrete grammar that calculates described Signal to Interference plus Noise Ratio in this step is grasped by those skilled in the art.

Step 102, according to described Signal to Interference plus Noise Ratio remaining dispatched users is divided into two classes, wherein, a class is an edge customer, and another kind of is central user, and the described Signal to Interference plus Noise Ratio of described edge customer is less than the described Signal to Interference plus Noise Ratio of described central user.

Here, the Signal to Interference plus Noise Ratio during according to the non-collaborative multicast communication of respectively treating dispatched users in the system that obtains in the step 101 is assessed each user's performance, and in view of the above the user is classified.Because the performance of Cell Center User is better than the performance of Cell Edge User usually, therefore, here described Signal to Interference plus Noise Ratio is high user is called central user, the user that described Signal to Interference plus Noise Ratio is low is called edge customer, and promptly the described Signal to Interference plus Noise Ratio of edge customer is less than the described Signal to Interference plus Noise Ratio of central user.

In actual applications, can also be directly according to treating that respectively the current location of dispatched users or other performance index carry out the classification of edge customer and central user, for example, when a user is defined as edge customer with this user apart from the position of its serving BS during greater than a certain predetermined threshold value, otherwise this user is defined as central user.

Among the present invention, edge customer will with the performance gain of the collaborative multicast communication of abundant acquisition, improve the edge performance of system as the user that must adopt collaborative multipoint transmission mode.And for central user, if its can and edge customer satisfy orthogonal property between a plurality of users of service simultaneously when dispatching at the same time, then can adopt collaborative multipoint transmission mode to it, otherwise, can only adopt non-collaborative multipoint transmission mode, subsequent step will carry out specific implementation to above-mentioned thought.

Concrete, carry out described classification according to described Signal to Interference plus Noise Ratio in this step and can adopt following two kinds of methods to realize:

Method one, with the described Signal to Interference plus Noise Ratio of remaining dispatched users, according to ascending rank order, that selects the described Signal to Interference plus Noise Ratio correspondence of top n treats dispatched users as edge customer, remaining treats that dispatched users then is central user.

Wherein, described N counts threshold value for default edge customer.In actual applications, those skilled in the art can be provided with suitable value to this value by emulation or according to practical application experience.

Method two, the described Signal to Interference plus Noise Ratio of remaining dispatched users is compared with default Signal to Interference plus Noise Ratio threshold value respectively, with described Signal to Interference plus Noise Ratio greater than described Signal to Interference plus Noise Ratio threshold value treat dispatched users as central user, treat that with what described Signal to Interference plus Noise Ratio was less than or equal to described Signal to Interference plus Noise Ratio threshold value dispatched users is as edge customer.

Here, described Signal to Interference plus Noise Ratio threshold value can be provided with suitable value by emulation or according to practical application experience to it by those skilled in the art for dividing the foundation of central user and edge customer.

In the said method one, the quantity of edge customer is fixed, and the quantity of edge customer is with current channel circumstance dynamic change in the method two, specifically selects which kind of method to be selected according to actual needs by those skilled in the art.

Step 103, according to $A_{u_{\mathrm{ij}}}={\mathrm{SINR}}_{u_{\mathrm{ij}}}^{\mathrm{CoMP}}{|}_{{\mathrm{\&theta;}}_{u_{\mathrm{ij}}}=1}/{\mathrm{SINR}}_{u_{\mathrm{ij}}}^{\mathrm{NoCoMP}},$ Calculate each and treat dispatched users u _Ij According to ${\mathrm{\&mu;}}_{u_{\mathrm{ij}}}=\max \{\&PartialD;,A_{u_{\mathrm{ij}}}\},$ Determine that each treats dispatched users u _IjThe quadrature thresholding

Here,

For treating dispatched users u _IjAdopt collaborative multipoint transmission mode and and the Signal to Interference plus Noise Ratio during the complete quadrature of its pairing user,

For treating dispatched users u _IjSignal to Interference plus Noise Ratio when adopting non-collaborative multipoint transmission mode,

For default quadrature thresholding is adjusted parameter, u _IjBe j user of i sub-district.

Need to prove, if user u in actual applications _IjBad with other user's orthogonality of service simultaneously, i.e. user u _IjAnd and its simultaneously serviced user between the quadrature performance parameter

Too little, then the performance behind the CoMP can be very poor.Thereby in order to ensure the performance behind the CoMP, the present invention will take into full account the orthogonality of guaranteeing between the multi-user when carrying out sky branch multi-subscriber dispatching.For this reason, in this step, each is treated dispatched users u _IjThe quadrature thresholding Determine.Below the choosing method and the principle of this quadrature thresholding in the present embodiment are analyzed explanation.

Consider the MIMO-OFDM cellular system of a M sub-district.There is N the base station of each sub-district _tIndividual antenna, each sub-district have U user, and every user has only an antenna.If u _IjJ the user who represents i sub-district, i=1 ..., M, j=1 ..., U.Simultaneously, K subcarrier arranged in the whole bandwidth of supposing the system, and definition $h_{u_{\mathrm{ij}}m}^k\&Element;{\mathrm{<figure-callout\; id="1"\; label="C"\; filenames="HSA00000051869600031.png"\; state="\{\{state\}\}">C</figure-callout>}}^{1\&times;N_t}$ Expression user u _IjAnd the channel between m base station on k subcarrier, $H_{u_{\mathrm{ij}}}^k=[h_{u_{\mathrm{ij}}1}^k,\&CenterDot;\&CenterDot;\&CenterDot;,h_{u_{\mathrm{ij}}M}^k]\&Element;{\mathrm{<figure-callout\; id="1"\; label="C"\; filenames="HSA00000051869600031.png"\; state="\{\{state\}\}">C</figure-callout>}}^{1\&times;{\mathrm{MN}}_t}$ Expression u _IjAnd the channel between all base stations on k subcarrier.M base station adopts ZF (ZF) precoding to descend line space to divide transmission to a plurality of users.

Here, suppose on each subcarrier, all to carry out independently definite process of transmission means of the present invention, for simplicity, all omitted the label of subcarrier below in analysis and the formula.Need to prove: under actual scene, each subcarrier is handled independently, may cause bigger complexity; In real system, a plurality of subcarriers can be handled as a unit unification, promptly only on some carrier waves, carry out definite process of transmission means of the present invention, can adopt the last transmission means of determining to get final product on other subcarriers, to reduce complexity.

At user u _Ij, the Signal to Interference plus Noise Ratio when it is carried out non-CoMP transmission is

${\mathrm{SINR}}_{u_{\mathrm{ij}}}^{\mathrm{NoCoMP}}=\frac{{\left|h_{u_{\mathrm{ij}}i}\right|}^2}{\underset{n=1,n\&NotEqual;i}{\overset{M}{\mathrm{\&Sigma;}}}{\left|h_{u_{\mathrm{ij}}n}\right|}^2+{\mathrm{\&sigma;}}^2},---\left(1\right)$

Wherein, σ ²The expression noise energy, n is the base station sequence number.

To user u _IjWhen carrying out the CoMP transmission, this user's Signal to Interference plus Noise Ratio is

${\mathrm{SINR}}_{u_{\mathrm{ij}}}^{\mathrm{CoMP}}=\frac{{\mathrm{\&theta;}}_{u_{\mathrm{ij}}}{\left|H_{u_{\mathrm{ij}}}\right|}^2}{{\mathrm{\&sigma;}}^2},---\left(2\right)$

Wherein, Be one less than 1 number, characterized user u _IjAnd and its simultaneously serviced user between orthogonal property. ${\mathrm{\&theta;}}_{u_{\mathrm{ij}}}={\cos }^2\mathrm{\&alpha;},$ α represents user u _IjThe angle of other users' that channel direction and while are serviced kernel that channel constitutes.If user u _IjWith the complete quadrature of described other user's channel, α=0 then, ${\mathrm{\&theta;}}_{u_{\mathrm{ij}}}=1.$

In order to make user u _IjObtained performance gains after adopting collaborative multipoint transmission mode, needs to satisfy:

${\mathrm{SINR}}_{u_{\mathrm{ij}}}^{\mathrm{CoMP}}\&GreaterEqual;{\mathrm{SINR}}_{u_{\mathrm{ij}}}^{\mathrm{NoCoMP}}---\left(3\right)$

To can get in formula (1) and (2) substitution formula (3):

${\mathrm{\&theta;}}_{u_{\mathrm{ij}}}\&GreaterEqual;\frac{{\mathrm{\&sigma;}}^2}{\underset{n=1,n\&NotEqual;i}{\overset{M}{\mathrm{\&Sigma;}}}{\left|h_{u_{\mathrm{ij}}n}\right|}^2+{\mathrm{\&sigma;}}^2}\&times;\frac{{\left|h_{u_{\mathrm{ij}}i}\right|}^2}{{\left|H_{u_{\mathrm{ij}}}\right|}^2}---\left(4\right)$

Wherein, formula (4) the right $\frac{{\mathrm{\&sigma;}}^2}{\underset{n=1,n\&NotEqual;i}{\overset{M}{\mathrm{\&Sigma;}}}{\left|h_{u_{\mathrm{ij}}n}\right|}^2+{\mathrm{\&sigma;}}^2}\&times;\frac{{\left|h_{u_{\mathrm{ij}}i}\right|}^2}{{\left|H_{u_{\mathrm{ij}}}\right|}^2}$ Equal ${\mathrm{SINR}}_{u_{\mathrm{ij}}}^{\mathrm{CoMP}}{|}_{{\mathrm{\&theta;}}_{u_{\mathrm{ij}}}=1}/{\mathrm{SINR}}_{u_{\mathrm{ij}}}^{\mathrm{NoCoMP}}.$

Order $A_{u_{\mathrm{ij}}}={\mathrm{SINR}}_{u_{\mathrm{ij}}}^{\mathrm{CoMP}}{|}_{{\mathrm{\&theta;}}_{u_{\mathrm{ij}}}=1}/{\mathrm{SINR}}_{u_{\mathrm{ij}}}^{\mathrm{NoCoMP}}.$

Be one less than 1 number, expression guarantees user u _IjWhen adopting CoMP with respect to non-CoMP performance boost to be arranged afterwards, user u _IjAnd and its simultaneously serviced user between the quadrature performance parameter

Lower limit.So,

Can be used as user u _IjThe quadrature thresholding.

But, notice: $\frac{1}{A_{u_{\mathrm{ij}}}}=\frac{{\mathrm{SINR}}_{u_{\mathrm{ij}}}^{\mathrm{CoMP}}{|}_{{\mathrm{\&theta;}}_{u_{\mathrm{ij}}}=1}}{{\mathrm{SINR}}_{u_{\mathrm{ij}}}^{\mathrm{NoCoMP}}}---\left(3\right)$

Characterized user u _IjCarrying out desirable CoMP (is u _IjWith the user with its pairing be completely orthogonal) time its Signal to Interference plus Noise Ratio multiple of promoting during with respect to non-collaborative multipoint transmission mode.Can with

Be considered as user u _IjCarry out the potentiality of performance boost behind the CoMP.Usually right

Lower edge customer,

Can be bigger, promptly the performance boost potentiality behind the CoMP are very big.

When big, promptly Less, according to formula (4), edge customer does not need and matches and satisfy very high orthogonality between the user, just can be so that the performance behind the CoMP has lifting with respect to non-CoMP.But,, only guarantee in order to give full play to the performance boost potentiality behind these edge customers CoMP ${\mathrm{\&theta;}}_{u_{\mathrm{ij}}}\&GreaterEqual;A_{u_{\mathrm{ij}}}$ Be not enough, so, in the present embodiment with user u _IjThe quadrature thresholding

Be set to:

${\mathrm{\&mu;}}_{u_{\mathrm{ij}}}=\max \{\&PartialD;,A_{u_{\mathrm{ij}}}\}.---\left(6\right)$

Wherein,

Adjust parameter for the quadrature thresholding, span is the arbitrary numerical value between 0～1.According to formula (6), when $A_{u_{\mathrm{ij}}}\&GreaterEqual;\&PartialD;$ The time, this user u _IjThe quadrature thresholding

For Can guarantee that the performance behind this user CoMP is better than the performance of non-CoMP; When $A_{u_{\mathrm{ij}}}<\&PartialD;$ The time, u _IjThe quadrature thresholding be

Performance behind this user CoMP is better than non-CoMP performance at this moment

Doubly.When Too hour, the determined quadrature thresholding of (6) formula substantially by

Decision, at this moment, for edge customer, this quadrature thresholding is too loose, only can guarantee that the performance behind the edge customer CoMP is better than non-CoMP, but can not give full play to the potentiality of performance boost behind the edge customer CoMP; When α → 1, (6) the definite quadrature thresholding of formula levels off to 1, this quadrature thresholding is too strict, almost can't select the user of quadrature, thereby only an edge customer is carried out the CoMP transmission, because the empty number of users of dividing of CoMP is very few, can cause scheduling time to become very long, thereby the overall performance of system is all bad.In actual applications, those skilled in the art can be according to above-mentioned principle, determines by emulation and can obtain better throughput of system and transmission data rate

Value.

In actual applications, step 103 also can be carried out before step 102.

Step 104, for each described edge customer, be higher than the principle of described separately quadrature thresholding according to the orthogonal property between a plurality of users that guarantee to serve simultaneously, determine this edge customer u _IjThe pairing user, determine that this edge customer and pairing user thereof adopt collaborative multipoint transmission mode and serve.

This step is used to each edge customer to determine pairing user (promptly carrying out the user of CoMP simultaneously), to increase the empty branch number of users of CoMP as far as possible, to reduce whole scheduling time.Preferably, can preferentially in all edge customers, select the pairing user of each edge customer, promptly in all edge customers, select the empty user of branch, had only when this moment, the selected sky that goes out divided number of users not reach sky that system can support as yet to divide the number of users maximum, from central user, select the pairing user again, in addition, the orthogonal property between a plurality of users that select described pairing user must guarantee to serve simultaneously is bigger, promptly is higher than described separately quadrature thresholding.So, can under the situation that does not reduce systematic function, farthest utilize on the one hand CoMP to improve the performance of edge customer, can guarantee to obtain farthest to improve the empty branch number of users of CoMP under the situation of CoMP gain on the other hand.

Particularly, as shown in Figure 2, this step can adopt following method to realize:

Step 201, the empty user of the branch set of initialization candidate, selected empty divide user's set and orthogonal users set, wherein, described candidate is empty to divide user's set to comprise current all edge customers of not serving, and described selected sky divides user's set and the set of described orthogonal users to be sky.

Step 202, from the empty user of the branch set of current described candidate, select a user, calculate when this user adds the current described empty user of branch and gather quadrature performance parameter between each user of the described empty branch user in back in gathering user, judge whether that quadrature performance parameter between all described users is all greater than the described quadrature thresholding of its respective user, if, then selected user is added in the described orthogonal users set, and in the empty user of the branch set of described candidate, delete this user, otherwise, in the empty user of the branch set of described candidate, delete this user.

Here, judge whether that quadrature performance parameter between all described users is all greater than the described quadrature thresholding of its respective user, orthogonal property between a plurality of users that are used to guarantee to serve simultaneously is higher than described separately quadrature thresholding, only described be judged as "Yes" in, just selected user is added in the described orthogonal users set, after this will in subsequent step, from described orthogonal users set, select a user to add in selected user's set, and to adopting the CoMP mode to transmit in selected user's set.As seen can guarantee that by this step sky divides the orthogonal property between the user.

Step 203, judge whether the empty user of the branch set of current described candidate is empty, if then execution in step 204, otherwise, re-execute step 202.

Step 204, judge whether current described orthogonal users set is empty, if then execution in step 206; Otherwise, execution in step 205.

Here, if current described orthogonal users set is for empty, then illustrate and in the edge customer of current not service, can't select the user who matches with the current user who has selected in user's set again, to change step 206 this moment over to, if current described orthogonal users set is not empty, then execution in step 206, so that select a user to put into the described selected empty user of branch set from described orthogonal users set.

Step 205, for each user in the current described orthogonal users set, calculate as this user and add current described selected empty branch user when gathering, that all users are empty in the described selected empty user of the branch set when dividing service and data transfer rate, select described in the current described orthogonal users set and the user of data transfer rate maximum correspondence joins in current described selected user's set, upgrade the empty user of the branch set of described candidate, the empty user of the branch set of candidate after the described renewal comprise remove in current all described edge customers of not serving current described selected user gather in user the user, return step 202.

When this step is used for dividing service according to sky and data transfer rate, from described orthogonal users set, select a user to put into the described selected empty user of branch set.

After executing, this step will re-execute step 202, the user that the user in continuing to select to gather with current described selected user match from current all described edge customers of not serving.

Above-mentioned steps is used for finishing the process of selecting the pairing user at edge customer, and following step will be used for selecting the pairing user in central user for edge customer.

Step 206, judge whether the number of users in current described selected user's set reaches the number of users upper limit that system dispatches simultaneously, if then execution in step 207, otherwise execution in step 208.

In this step, if the number of users of judging in current selected user's set does not reach the number of users upper limit that system dispatches simultaneously, then change the user is matched in step 208 continuation in central user selection over to, with under the prerequisite of guaranteed performance, the number of users that increase is engaged in the space-time sub-service, detailed process is similar to the method for selecting in edge customer.If the number of users of judging in current selected user's set reaches the number of users upper limit that system dispatches simultaneously, the user who then changes in step 207 pair current described selected user's set carries out the CoMP transmission.

Here, determine that the method for the number of users upper limit that described system dispatches is simultaneously grasped by those skilled in the art, do not repeat them here.

Step 207, determine that user in current described selected user's set adopts collaborative multipoint transmission mode and serves, judge whether that all edge customers are all serviced, if then execution in step 105, otherwise, return step 201.

Here, described service is promptly carried out transfer of data to the user, does not repeat them here.

Step 208, the empty user of branch of renewal candidate gather, and the empty branch of the described candidate user set after the described renewal comprises current all described central user of not serving.

Step 209, from the empty user of the branch set of current described candidate, select a user, calculate when this user adds the current described empty user of branch and gather quadrature performance parameter between each user of the described empty branch user in back in gathering user, judge whether that quadrature performance parameter between all described users is all greater than the described quadrature thresholding of its respective user, if, then selected user is added in the described orthogonal users set, and in the empty user of the branch set of described candidate, delete this user, otherwise, in the empty user of the branch set of described candidate, delete this user.

Step 210, judge whether the empty user of the branch set of current described candidate is empty, if then execution in step 211, otherwise, re-execute step 209.

Step 211, judge whether current described orthogonal users set is empty, if then execution in step 213; Otherwise, execution in step 212.

In this step, if current described orthogonal users set is for empty, illustrate then and in the central user of current not service, can't select the user who matches with the current user who has selected in user's set again that the user who then changes in step 213 pair current selected user's set carries out the CoMP transmission.

Step 212, for each user in the current described orthogonal users set, calculate as this user and add current described selected empty branch user when gathering, that all users are empty in the described selected empty user of the branch set when dividing service and data transfer rate, select described in the current described orthogonal users set and the user of data transfer rate maximum correspondence joins in current described selected user's set, upgrade the empty user of the branch set of described candidate, the empty user of the branch set of candidate after the described renewal comprise remove in current all described central user of not serving current described selected user gather in user the user, return step 209.

Step 213, determine that user in current described selected user's set adopts collaborative multipoint transmission mode and serves, judge whether that all edge customers are all serviced, if then execution in step 105, otherwise, return step 201.

Step 105, determine that user not serviced in the described central user adopts non-collaborative multipoint transmission mode and serves.

This step is used for the user not serviced to all central user, promptly is not selected as the pairing user's of edge customer central user, adopts non-collaborative multicast communication.If by said process as can be seen a central user be not selected as the pairing user of edge customer, illustrate that then the orthogonality between itself and edge customer is lower, can not obtain CoMP gain preferably, therefore, the CoMP gain of system can be effectively guaranteed in the differentiation to CoMP user and non-CoMP user that realizes of present embodiment.

In sum, the present invention can reasonably distinguish CoMP user and non-CoMP user, can determine user's CoMP transmission mode (single user's transmission or multi-user's transmission) simultaneously, carries out the empty multi-user of the branch service of CoMP.Below by an examples of simulation, further specify the performance advantage that the embodiment of the invention one is had with respect to existing method.

Concrete simulated conditions is as shown in table 1:

The simulation parameter title	The simulation parameter value
		Cell topology	3 hexagonal cell
Station spacing	500m
		Antenna configurations	Base station 2 antennas, user's 1 antenna
The user scatters	Every sub-district 10 users, uniformly dispersing in the sub-district

Path loss	36.3+37.6log (d), the unit of d is a rice
		Time domain channel	The Rayleigh multipath channel, power delay profile
Number of sub carrier wave	600 subcarriers, per 12 subcarriers constitute a Resource Block
		Noise factor	9dBi
Transmitting power	46dBm
		Power division	Single base station power is limited, and the frequency domain constant power distributes, and the empty multi-user of branch constant power distributes
Precoding	ZF precoding (ZFBF)
		DMRS	6 resource particle of every user
Data transfer rate calculates	Consider signaling consumption
		Operating unit	With 5 Resource Block is that the unit carries out CoMP user's division, divides CoMP user on each unit independently

Table 1

When calculating the user's data rate, consider signaling consumption taking to the downlink data transmission resource.If when not considering the DMRS signaling consumption, certain user's data rate is R, then consider the DMRS signaling consumption after, this user's data rate is $R^{\#}=\frac{116-6*L}{116}\&times;R,$ ......

Wherein, L represents the total number of users together serviced with this user.

Fig. 3 determines the performance comparison schematic diagram of method for adopting the present invention under the above-mentioned simulated conditions and traditional differentiation CoMP user and non-CoMP user's transmission means.

As can be seen from Figure 3: the present invention can determine (the corresponding curve of abscissa 0.2-0.4 part in referring to figure) under the consistent prerequisite of method in assurance marginal date rate and conventional transmission mode, improve centre data rate (referring to the corresponding curve of abscissa 0.6-1.2 part among the figure) effectively, and then improve the performance of entire system.For example, see from Fig. 3 that definite method of conventional transmission mode probability distribution value of correspondence when data transfer rate is 0.8 bps/hertz is 0.85, and the probability distribution value of the present invention's correspondence when same data transfer rate is 0.78.

In sum, more than be preferred embodiment of the present invention only, be not to be used to limit protection scope of the present invention.Within the spirit and principles in the present invention all, any modification of being done, be equal to replacement, improvement etc., all should be included within protection scope of the present invention.

Claims (4)

1. definite method of a collaborative multicast communication downlink transmission mode is characterized in that, this method may further comprise the steps:

A, the Signal to Interference plus Noise Ratio when calculating each non-collaborative multicast communication for the treatment of dispatched users; Current location according to described Signal to Interference plus Noise Ratio or user is divided into two classes with remaining dispatched users, and wherein, a class is an edge customer, and another kind of is central user, and the described Signal to Interference plus Noise Ratio of described edge customer is less than the described Signal to Interference plus Noise Ratio of described central user;

According to $A_{u_{\mathrm{ij}}}={\mathrm{SINR}}_{u_{\mathrm{ij}}}^{\mathrm{CoMp}}{|}_{0_{u_{\mathrm{ij}}}=1}/{\mathrm{SINR}}_{u_{\mathrm{ij}}}^{\mathrm{NoCoMP}},$ Calculate each and treat dispatched users u _Ij

According to ${\mathrm{\&mu;}}_{u_{\mathrm{ij}}}=\max \{\&PartialD;,A_{u_{\mathrm{ij}}}\},$ Determine that each treats dispatched users u _IjThe quadrature thresholding

Wherein,

Be user u _IjAdopt collaborative multipoint transmission mode and and the Signal to Interference plus Noise Ratio during the complete quadrature of its pairing user,

Be user u _IjSignal to Interference plus Noise Ratio when adopting non-collaborative multipoint transmission mode,

For default quadrature thresholding is adjusted parameter, u _IjBe j user of i sub-district;

B, for each described edge customer, the principle that is higher than described separately quadrature thresholding according to the orthogonal property between a plurality of users that guarantee to serve simultaneously, determine the pairing user of this edge customer, determine that this edge customer and pairing user thereof adopt collaborative multipoint transmission mode and serve;

C, determine that user not serviced in the described central user adopts non-collaborative multipoint transmission mode and serves.

2. method according to claim 1 is characterized in that, described step b comprises:

B1, the empty user of the branch set of initialization candidate, selected empty divide user's set and orthogonal users set, wherein, described candidate is empty to divide user's set to comprise current all described edge customers of not serving, and described selected sky divides user's set and the set of described orthogonal users to be sky;

B2, from the empty user of the branch set of current described candidate, select a user, calculate when this user adds the current described empty user of branch and gather quadrature performance parameter between each user of the described empty branch user in back in gathering user, judge whether that quadrature performance parameter between all described users is all greater than the described quadrature thresholding of its respective user, if, then selected user is added in the described orthogonal users set, and in the empty user of the branch set of described candidate, delete this user, otherwise, in the empty user of the branch set of described candidate, delete this user;

B3, judge whether the empty user of the branch set of current described candidate is empty, if, execution in step b4 then, otherwise, re-execute step b2;

B4, judge whether current described orthogonal users set is empty, if, execution in step b6 then; Otherwise, execution in step b5;

B5, for each user in the current described orthogonal users set, calculate as this user and add current described selected empty branch user when gathering, that all users are empty in the described selected empty user of the branch set when dividing service and data transfer rate, select described in the current described orthogonal users set and the user of data transfer rate maximum correspondence joins in current described selected user's set, upgrade the empty user of the branch set of described candidate, the empty user of the branch set of candidate after the described renewal comprise remove in current all described edge customers of not serving current described selected user gather in user the user, return step b2;

B6, judge whether the number of users in current described selected user's set reaches the number of users upper limit that system dispatches simultaneously, if, execution in step b7 then, otherwise execution in step b8;

B7, determine that the user in current described selected user's set adopts collaborative multipoint transmission mode and is taken after mixing with liquid affair, judge whether that all edge customers are all serviced, if, execution in step c then, otherwise, step b1 returned;

B8, the empty user of branch of renewal candidate gather, and the empty branch of the described candidate user set after the described renewal comprises current all described central user of not serving;

B9, from the empty user of the branch set of current described candidate, select a user, calculate when this user adds the current described empty user of branch and gather quadrature performance parameter between each user of the described empty branch user in back in gathering user, judge whether that quadrature performance parameter between all described users is all greater than the described quadrature thresholding of its respective user, if, then selected user is added in the described orthogonal users set, and in the empty user of the branch set of described candidate, delete this user, otherwise, in the empty user of the branch set of described candidate, delete this user;

B10, judge whether the empty user of the branch set of current described candidate is empty, if, execution in step b11 then, otherwise, re-execute step b9;

B11, judge whether current described orthogonal users set is empty, if, execution in step b13 then; Otherwise, execution in step b12;

B12, for each user in the current described orthogonal users set, calculate as this user and add current described selected empty branch user when gathering, that all users are empty in the described selected empty user of the branch set when dividing service and data transfer rate, select described in the current described orthogonal users set and the user of data transfer rate maximum correspondence joins in current described selected user's set, upgrade the empty user of the branch set of described candidate, the empty user of the branch set of candidate after the described renewal comprise remove in current all described central user of not serving current described selected user gather in user the user, return step b9;

B13, determine that user in current described selected user's set adopts multi-user's collaborative multipoint transmission mode and serves, judge whether that all edge customers are all serviced, if, execution in step c then, otherwise, step b1 returned.

3. method according to claim 1 is characterized in that, according to described Signal to Interference plus Noise Ratio remaining dispatched users is divided into two classes among the step a and comprises:

Described Signal to Interference plus Noise Ratio with remaining dispatched users, according to ascending rank order, that selects the described Signal to Interference plus Noise Ratio correspondence of top n treats dispatched users as edge customer, and remaining treats that dispatched users then is central user, wherein, described N counts threshold value for default edge customer.

4. method according to claim 1 is characterized in that, according to described Signal to Interference plus Noise Ratio remaining dispatched users is divided into two classes among the step a and comprises:

The described Signal to Interference plus Noise Ratio of remaining dispatched users is compared with the Signal to Interference plus Noise Ratio threshold value of presetting respectively, with described Signal to Interference plus Noise Ratio greater than described Signal to Interference plus Noise Ratio threshold value treat dispatched users as central user, treat that with what described Signal to Interference plus Noise Ratio was less than or equal to described Signal to Interference plus Noise Ratio threshold value dispatched users is as edge customer.

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