CN102196585B - 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 downlink transmission mode of coordinated multi-point transmission

Technical field

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

Background technology

CoMP is one of important technology in long evolving system (LTE), and its core concept is by multipoint cooperative, forms 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, need more downlink signaling, be mainly that the DMRS letter is modern, these signalings will take the descending channel resource for transfer of data.

Consider the performance gain of CoMP and the signaling consumption that CoMP brings, for the certain user, demodulated reference signal (DMRS) signaling consumption that its performance gain brought because of CoMP can be caused by CoMP balances out, and even there will be these users' equivalent CoMP performance gain is negative situation.Therefore, in order to realize better systematic function, need to 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: during using non-CoMP, the user of poor-performing, as CoMP user, and is transmitted according to the CoMP-SU mode these users, and this CoMP-SU mode is the mode that a user is served in a plurality of base stations 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 extend whole scheduling time, thereby affects 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 downlink transmission mode of coordinated multi-point transmission formula, and the method can, when effectively improving the system edges performance, guarantee the center performance of system.

In order to achieve the above object, the technical scheme that the present invention proposes is:

A kind of definite method of downlink transmission mode of coordinated multi-point transmission, the method comprises the following steps:

A, the Signal to Interference plus Noise Ratio while calculating each non-collaborative multicast communication until dispatched users; According to described Signal to Interference plus Noise Ratio or user's current location, remained dispatched users is divided into to two classes, wherein, a class is edge customer, another kind of centered by the user, 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,

For user u _IjSignal to Interference plus Noise Ratio when adopting collaborative multipoint transmission mode and matching the complete quadrature of user with it, For user u _IjSignal to Interference plus Noise Ratio while adopting non-collaborative multipoint transmission mode,

For default quadrature thresholding is adjusted parameter, u _IjBe j user of i community;

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

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

In sum, definite method of the downlink transmission mode of coordinated multi-point transmission 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.

The accompanying drawing explanation

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

The flow chart that Fig. 2 is step 104 in Fig. 1;

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

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 while being effectively to improve non-collaborative multicast communication in view of the Main Function of working in coordination with multicast communication, the dry less dispatched users (hereinafter referred to 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, fully to obtain the performance gain of collaborative multicast communication, improve the edge performance of system.Simultaneously, in order to reduce the integrated scheduling time, the present invention will serve a plurality of users as far as possible when each scheduling simultaneously.; for each edge customer; will be according to the orthogonal property between a plurality of users that guarantee to serve simultaneously higher than the principle of quadrature thresholding separately; select the pairing user (user who simultaneously serves) of this edge customer from remained dispatched users; if this edge customer has the pairing user, determine that 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 this edge customer and pairing user thereof adopt the mode of the collaborative multicast communication in alone family.And, for the user who matches the user except edge user and being selected as in remained dispatched users, adopt the mode of non-collaborative multicast communication.In 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, will obtain CoMP performance gain preferably.Therefore, the present invention determines its pairing user higher than the principle of quadrature thresholding separately for each edge customer by the orthogonal property between a plurality of users according to guarantee to serve simultaneously, can guarantee to obtain under the prerequisite of CoMP performance gain, increase is with the number of users of space-time sub-service business, reduce the scheduling time of entire system, and then guarantee the center performance of system.

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

Step 101, the Signal to Interference plus Noise Ratio while calculating each non-collaborative multicast communication until 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, remained dispatched users is divided into to two classes, wherein, a class is edge customer, another kind of centered by the user, 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, according to the Signal to Interference plus Noise Ratio when the non-collaborative multicast communication of dispatched users respectively in the system obtained in step 101, assess each user's performance, and accordingly the user is classified.Because the performance of Cell Center User is better than the performance of Cell Edge User usually, therefore, here by described Signal to Interference plus Noise Ratio, high user is called central user, the user that described Signal to Interference plus Noise Ratio is low is called edge customer, and 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 respectively treating that 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 by this user when the position of its serving BS is greater than a certain predetermined threshold value, otherwise this user is defined as to central user.

In the present invention, edge customer will, as the user that must adopt collaborative multipoint transmission mode, fully to obtain the performance gain of collaborative multicast communication, improve the edge performance of system.And for central user, if its can and edge customer meet the orthogonal property between a plurality of users of service simultaneously while dispatching at the same time, 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, by the described Signal to Interference plus Noise Ratio of remained dispatched users, according to the sequence of ascending order, dispatched users is as edge customer to select corresponding the treating of the described Signal to Interference plus Noise Ratio of top n, remaining treats user centered by dispatched users.

Wherein, described N is that default edge customer is counted threshold value.In actual applications, those skilled in the art can arrange suitable value to this value by emulation or according to practical application experience.

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

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

In said method one, the quantity of edge customer is fixed, and in method two, the quantity of edge customer is with current channel circumstance dynamic change, 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 _IjSignal to Interference plus Noise Ratio when adopting collaborative multipoint transmission mode and matching the complete quadrature of user with it,

For treating dispatched users u _IjSignal to Interference plus Noise Ratio while adopting non-collaborative multipoint transmission mode, For default quadrature thresholding is adjusted parameter, u _IjBe j user of i community.

It should be noted that, if user u in actual applications _IjBad with other user's orthogonality of service simultaneously, i.e. user u _IjAnd and its quadrature performance parameter between serviced user simultaneously Too little, the performance after CoMP can be very poor.Thereby, in order to ensure the performance after CoMP, the present invention, when carrying out sky minute multi-subscriber dispatching, will take into full account the orthogonality of guaranteeing between the multi-user.For this reason, in this step, each is treated to dispatched users u _IjThe quadrature thresholding

Determine.Below choosing method and the principle of this quadrature thresholding in the present embodiment are carried out to analytic explanation.

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

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

For user u _Ij, Signal to Interference plus Noise Ratio when it is carried out to 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 ²Mean noise energy, n is the base station sequence number.

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

In order to make user u _IjObtain performance gain after adopting collaborative multipoint transmission mode, need to meet:

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

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

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

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 and be less than 1 number, mean to guarantee user u _IjWhile adopting CoMP with respect to non-CoMP, performance boost to be arranged afterwards, user u _IjAnd and its quadrature performance parameter between serviced user simultaneously

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 by

Be considered as user u _IjCarry out the potentiality of performance boost after CoMP.Usually right Lower edge customer,

Can be larger, the performance boost potentiality after CoMP are very large.

When larger,

Less, according to formula (4), edge customer does not need and matches between the user to meet very high orthogonality, just can be so that the performance after CoMP has lifting with respect to non-CoMP.But, in order to give full play to the performance boost potentiality after these edge customers CoMP, only guarantee ${\mathrm{\&theta;}}_{u_{\mathrm{ij}}}\&GreaterEqual;A_{u_{\mathrm{ij}}}$ Inadequate, so, in the present embodiment by 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 after this user CoMP is better than the performance of non-CoMP; When $A_{u_{\mathrm{ij}}}<\&PartialD;$ The time, u _IjThe quadrature thresholding be

Now the performance after this user CoMP is better than non-CoMP performance

Doubly.When

Too hour, the determined quadrature thresholding of (6) formula substantially by Determine, now, for edge customer, this quadrature thresholding is too loose, only can guarantee that the performance after edge customer CoMP is better than non-CoMP, but can not give full play to the potentiality of performance boost after 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 to the CoMP transmission, because the empty minute number of users 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, by emulation, determines 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, higher than the principle of described quadrature thresholding separately, determine this edge customer u according to the orthogonal property between a plurality of users that guarantee to serve simultaneously _IjThe pairing user, determine that this edge customer and pairing user thereof adopt collaborative multipoint transmission mode and served.

This step is used to each edge customer to determine pairing user (simultaneously carrying out the user of CoMP), to increase the empty minute 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, select empty minute user in all edge customers, only have when the selected sky gone out now divides number of users not yet to reach sky that system can support to divide the number of users maximum, select again the pairing user from central user, in addition, the orthogonal property between a plurality of users that select described pairing user must guarantee simultaneously to serve is larger, higher than described quadrature thresholding separately.So, can farthest utilize CoMP to improve the performance of edge customer in the situation that do not reduce systematic function on the one hand, can farthest improve the empty minute number of users of CoMP in the situation that guarantee to obtain the CoMP gain on the other hand.

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

Step 201, initialization candidate user's set in empty minute, user's set in selected empty minute and orthogonal users set, wherein, the current all not edge customers of service of the empty minute user's set-inclusion of described candidate, user's set in described selected empty minute and described orthogonal users set are sky.

Step 202, from current described candidate user's set in empty minute, select a user, calculate quadrature performance parameter between the user that after this user adds current described sky to divide the user to gather described sky divides each user of user in gathering, judge whether that quadrature performance parameter between all described users all is greater than the described quadrature thresholding of its respective user, if, selected user is added in described orthogonal users set, and delete this user in described candidate user's set in empty minute, otherwise, in described candidate user's set in empty minute, delete this user.

Here, judge whether that quadrature performance parameter between all described users all is greater than the described quadrature thresholding of its respective user, for the orthogonal property between a plurality of users that guarantee to serve simultaneously higher than described quadrature thresholding separately, only described be judged as "Yes" in, just selected user is added in 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 in selected user's set, adopting the CoMP mode to transmit.By this step, can guarantee the empty minute orthogonal property between the user as seen.

Step 203, judge whether the user's set in empty minute of current described candidate is empty, if so, performs step 204, otherwise, re-execute step 202.

Step 204, judge that whether current described orthogonal users set is empty, if so, performs step 206; Otherwise, perform step 205.

Here, if current described orthogonal users set is empty, illustrate and can't select again the user that the user in gathering with current selected user is matched in the edge customer of current not service, now will proceed to step 206, if current described orthogonal users set is not empty, perform step 206, in order to select a user to put into user's set in described selected empty minute from described orthogonal users set.

Step 205, for each user in current described orthogonal users set, calculate when this user adds a current described selected empty minute user to gather, in user's set in described selected empty minute during all users service in empty minute and data transfer rate, select with user corresponding to data transfer rate maximum, to join in current described selected user's set described in current described orthogonal users set, upgrade described candidate user's set in empty minute, candidate after described renewal is empty to be divided in the current all described edge customers of not serving of user's set-inclusion except the current described user the user in user's set that selected, return to step 202.

This step for divide when service according to sky and data transfer rate, from described orthogonal users set, select a user to put into user's set in described selected empty minute.

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 is matched from the described edge customer of current all not services.

Above-mentioned steps has been used for selecting at edge customer pairing user's process, and following step will be for selecting the pairing user in central user for edge customer.

Step 206, judge that whether the number of users in current described selected user's set reaches the number of users upper limit that system is dispatched simultaneously, if so, performs step 207, otherwise performs 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 is dispatched simultaneously, proceed to step 208 and continue the selection of being matched the user in central user, with under the prerequisite of guaranteed performance, increase is with the number of users of space-time sub-service business, and 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 is dispatched simultaneously, the user who proceeds 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 is dispatched is simultaneously grasped by those skilled in the art, do not repeat them here.

Step 207, determine that the user in current described selected user's set adopts collaborative multipoint transmission mode and served, judge whether that all edge customers are all serviced, if so, perform step 105, otherwise, step 201 returned to.

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

Step 208, renewal candidate user's set in empty minute, the described candidate after described renewal is empty divides user's set-inclusion current all not described central user of service.

Step 209, from current described candidate user's set in empty minute, select a user, calculate quadrature performance parameter between the user that after this user adds current described sky to divide the user to gather described sky divides each user of user in gathering, judge whether that quadrature performance parameter between all described users all is greater than the described quadrature thresholding of its respective user, if, selected user is added in described orthogonal users set, and delete this user in described candidate user's set in empty minute, otherwise, in described candidate user's set in empty minute, delete this user.

Step 210, judge whether current described candidate user's set in empty minute is empty, if so, performs step 211, otherwise, re-execute step 209.

Step 211, judge that whether current described orthogonal users set is empty, if so, performs step 213; Otherwise, perform step 212.

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

Step 212, for each user in current described orthogonal users set, calculate when this user adds a current described selected empty minute user to gather, in user's set in described selected empty minute during all users service in empty minute and data transfer rate, select with user corresponding to data transfer rate maximum, to join in current described selected user's set described in current described orthogonal users set, upgrade described candidate user's set in empty minute, candidate after described renewal is empty to be divided in the current all described central user of not serving of user's set-inclusion except the current described user the user in user's set that selected, return to step 209.

Step 213, determine that the user in current described selected user's set adopts collaborative multipoint transmission mode and served, judge whether that all edge customers are all serviced, if so, perform step 105, otherwise, step 201 returned to.

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

This step, for the user not serviced to all central user, is not selected as the pairing user's of edge customer central user, adopts non-collaborative multicast communication.By said process, can find out if a central user is not selected as the pairing user of edge customer, illustrate that 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 the present embodiment is realized.

In sum, the present invention can reasonably distinguish CoMP user and non-CoMP user, can determine user's CoMP transmission mode (transmission of alone family or multi-user transmission) simultaneously, carries out the empty minute multi-user services of CoMP.Below by an examples of simulation, further illustrate the performance advantage that the embodiment of the present invention one has 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 configuration	Base station 2 antennas, user's 1 antenna
The user scatters	Uniformly dispersing in 10 user ，Zai communities, every community
		Path loss	36.3+37.6log (d), the unit of d is rice
Time domain channel	The Rayleigh multipath channel, power delay profile

Number of sub carrier wave	600 subcarriers, every 12 subcarriers form 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 empty minute multi-user's constant power distributes
Precoding	ZF precoding (ZFBF)
		DMRS	6 resource particle of every user
Data transfer rate calculates	Consider signaling consumption
		Operating unit	5 Resource Block of take carry out CoMP user's division as unit, divide independently CoMP user on each unit

Table 1

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

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

Fig. 3 is for adopting the present invention under above-mentioned simulated conditions and traditional differentiation CoMP user and non-CoMP user's transmission means to determine that the Performance Ratio of method is than schematic diagram.

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

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

Claims (3)

1. definite method of a downlink transmission mode of coordinated multi-point transmission, is characterized in that, the method comprises the following steps:

A, the Signal to Interference plus Noise Ratio while calculating each non-collaborative multicast communication until dispatched users; According to described Signal to Interference plus Noise Ratio or user's current location, remained dispatched users is divided into to two classes, wherein, a class is edge customer, another kind of centered by the user, 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

Calculate each and treat dispatched users u _Ij

According to

Determine that each treats dispatched users u _IjThe quadrature thresholding

Wherein, For user u _IjSignal to Interference plus Noise Ratio when adopting collaborative multipoint transmission mode and matching the complete quadrature of user with it, For user u _IjSignal to Interference plus Noise Ratio while adopting non-collaborative multipoint transmission mode,

For default quadrature thresholding is adjusted parameter, u _IjBe j user of i community;

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

C, determine that user not serviced in described central user adopts non-collaborative multipoint transmission mode and served;

Described step b comprises:

B1, initialization candidate user's set in empty minute, user's set in selected empty minute and orthogonal users set, wherein, the current all not described edge customers of service of the empty minute user's set-inclusion of described candidate, user's set in described selected empty minute and described orthogonal users set are sky;

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

B3, judge whether the user's set in empty minute of current described candidate is empty, if so, performs step b4, otherwise, re-execute step b2;

B4, judge that whether current described orthogonal users set is empty, if so, performs step b6; Otherwise, execution step b5;

B5, for each user in current described orthogonal users set, calculate when this user adds a current described selected empty minute user to gather, in user's set in described selected empty minute during all users service in empty minute and data transfer rate, select with user corresponding to data transfer rate maximum, to join in user's set in current described selected empty minute described in current described orthogonal users set, upgrade described candidate user's set in empty minute, divide the user the user in user's set except current described selected sky in the described edge customers of the current all not services of candidate's sky minute user's set-inclusion after described renewal, return to step b2,

B6, judge whether the current described selected empty minute number of users in user's set reaches the number of users upper limit that system is dispatched simultaneously, if so, performs step b7, otherwise execution step b8;

B7, determine that the current described selected empty minute user in user's set adopts collaborative multipoint transmission mode and served, judge whether that all edge customers are all serviced, if so, perform step c, otherwise, step b1 returned to;

B8, renewal candidate user's set in empty minute, the described candidate after described renewal is empty divides user's set-inclusion current all not described central user of service;

B9, from current described candidate user's set in empty minute, select a user, calculate quadrature performance parameter between the user that after this user adds current described sky to divide the user to gather described sky divides each user of user in gathering, judge whether that quadrature performance parameter between all described users all is greater than the described quadrature thresholding of its respective user, if, selected user is added in described orthogonal users set, and delete this user in described candidate user's set in empty minute, otherwise, in described candidate user's set in empty minute, delete this user;

B10, judge whether the user's set in empty minute of current described candidate is empty, if so, performs step b11, otherwise, re-execute step b9;

B11, judge that whether current described orthogonal users set is empty, if so, performs step b13; Otherwise, execution step b12;

B12, for each user in current described orthogonal users set, calculate when this user adds a current described selected empty minute user to gather, in user's set in described selected empty minute during all users service in empty minute and data transfer rate, select with user corresponding to data transfer rate maximum, to join in user's set in current described selected empty minute described in current described orthogonal users set, upgrade described candidate user's set in empty minute, divide the user the user in user's set except current described selected sky in the described central user of the current all not services of candidate's sky minute user's set-inclusion after described renewal, return to step b9,

B13, determine that the current described selected empty minute user in user's set adopts multi-user's collaborative multipoint transmission mode and served, judge whether that all edge customers are all serviced, if so, perform step c, otherwise, step b1 returned to.

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

Described Signal to Interference plus Noise Ratio by remained dispatched users, according to the sequence of ascending order, dispatched users is as edge customer to select corresponding the treating of the described Signal to Interference plus Noise Ratio of top n, and remaining treats user centered by dispatched users, wherein, described N is that default edge customer is counted threshold value.

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

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

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