CN101436891A - Method for scheduling global proportionality equitableness of multiple base stations and multiuser - Google Patents

Abstract

The invention discloses a method for dispatching overall scale fairness of multiple base stations and multiple users, which comprises the following steps: initializing all average throughputs at a first time slot; selecting users transmitted by each base station at the t time slot for all base stations; setting a value of an indicative function selected by the users at the t time slot for all the base stations; updating respective average throughput by each base station; mutually broadcasting the respective average throughput by all the base stations; and obtaining the total average throughput obtained by each user from the base stations by each base station. The method improves the total average throughput of each user, promotes stability of the total average throughput of each user, has high fairness of the total average throughput among the users, can be fully executed asynchronously, can ensure good astringency at asynchronous execution, and finally converge to the same average throughput as a standard overall scale fairness dispatching algorithm.

Description

A kind of method for scheduling global proportionality equitableness of multi-BS (base station) multi-user

Technical field

The present invention relates to wireless communication technology field, particularly relate to a kind of method for scheduling global proportionality equitableness of multi-BS (base station) multi-user.

Background technology

At present, the technical research at B3G and 4G has obtained remarkable progress in the world, and the collaboration communication technology has begun to move towards to use from theory as a technological highlights in the next generation mobile communication system.And China has carried out a large amount of beforehand research and input on collaboration communication.But, the trial of practical communication system does not also appear collaboration communication thought is applied at present.

The network configuration that a kind of a plurality of users in a plurality of base station are transmitted simultaneously as shown in Figure 1.Time-multiplexed mode is adopted in base station and user-user information transmission, can guarantee that like this a base station can provide service to a plurality of user terminals.Because the fading characteristic of wireless channel, each base station all exists certain probability user adjacent thereto to carry out message transmission in the mobile network.In order to make full use of the characteristic of wireless fading channel, greedy scheduling strategy commonly used allows each base station to transmit each best user of time slot selective channel situation, but greedy dispatching algorithm will cause the user near apart from the base station to take the BTS channel resource in the overwhelming majority time, thereby make the user away from the base station can't obtain enough service time slots, cause between the user reducing in the fairness of information resources aspect utilizing.The algorithm of time slot allocation fairness is the polled transmission algorithm between another kind of commonly used assurance user, and promptly the base station is served each user in turn, no matter the current channel conditions of this user how.This algorithm may cause the waste of information resources.For example, if the user of current selection transmission is under the very poor channel condition, all transmission this moment all may be failed, and will cause the time interval resource waste like this.Comparatively speaking, the proportional fairness algorithm synthesis has been considered fairness between multi-user diversity and user,, can address the above problem preferably the situation of single base station as choice criteria with the ratio of average throughput in current achievable rate and the time window.For the wireless network of many base stations, this proportional fairness algorithm is to be difficult to adapt to its poor-performing.

The Proportional Fair algorithm that in multi-user's scheduling transmission task of down link, adopts QualCom company to propose in present HSDPA (High Speed Downlink Packet Access, the high speed downlink packet inserts) system.This algorithm can utilize the multi-user diversity characteristic of wireless fading channel on the one hand, improves the throughput of system; The user that can guarantee the channel conditions difference on the other hand again obtains high relatively throughput, and the raising system is to the fairness of different user service.Its concrete steps are described below:

The first step: at first time slot, all average throughputs of initialization.When time slot t=1,, make R to all base station n and user m _{N, m}(t)=1, wherein, n=1,2 ..., N, m=1,2 ..., M.

Second step:, select the user of this base station t slot transmission according to following criterion to each base station n:

$m_n^{*}\left(t\right)=\underset{m=\mathrm{1,2},\·\·\·,M}{\arg \max }\frac{r_{n,m}\left(t\right)}{{\stackrel{\‾}{R}}_{n,m}(t-1)}$

The 3rd step: to all base station n, the user that t time slot is set selects the value of indicative function, and is as follows:

The 4th step: average throughput is separately upgraded in each base station:

${\stackrel{\‾}{R}}_{n,m}\left(t\right)=\frac{t-1}{t}{\stackrel{\‾}{R}}_{n,m}(t-1)+\frac{1}{t}{r}_{n,m}\left(t\right)I_{n,m}\left(t\right)$

Wherein, n=1,2 ..., N, m=1,2 ..., M.

But this traditional Proportional Fair algorithm is based on single base station, can interactive information between a plurality of base stations in the future communications system, utilize the virtual antenna array technology, a plurality of base stations provide service can be simultaneously for a plurality of users, finish scheduling under the multi-BS (base station) multi-user environment so need a kind of new dispatching algorithm badly.

Summary of the invention

The problem to be solved in the present invention provides a kind of method for scheduling global proportionality equitableness of multi-BS (base station) multi-user, realizing a plurality of base station collaborations, for the user is provided at service guarantee on throughput and the fairness.

For achieving the above object, the invention provides a kind of method for scheduling global proportionality equitableness of multi-BS (base station) multi-user, said method comprising the steps of: at first time slot, all average throughputs of initialization; To all base stations, select the user of each base station t slot transmission; To all base stations, the user that t time slot is set selects the value of indicative function; Average throughput is separately upgraded in each base station; All base stations are broadcasting average throughput separately mutually; Each base station obtains the overall average throughput that each user obtains from all base stations.

Wherein, in the step of described all average throughputs of initialization, specifically comprise: when time slot t=1,, make R all base station n and user m _{N, m}(t)=1, wherein, n=1,2 ..., N, m=1,2 ..., M, N are the number that can carry out the base station of collaboration communication in the network, M be in the network can with the number of the user terminal of each base station communication, R _{N, m}(t) be to finish the local average throughput that user m obtains from base station n by the end of t timeslot scheduling.

Wherein,, in the user's of t slot transmission step, specifically comprise: in each base station of described selection according to formula

$m_n^{*}\left(t\right)=\underset{m=\mathrm{1,2},\·\·\·,M}{\arg \max }\frac{r_{n,m}\left(t\right)-{\stackrel{\‾}{R}}_{n,m}(t-1)}{{\hat{R}}_m(t-1)}$

Select the user of base station n t slot transmission, wherein, r _{N, m}(t) be in t time slot, the achievable rate that base station n can provide for user m, R _{N, m}(t-1) be to finish by the end of t-1 timeslot scheduling, the local average throughput that user m obtains from base station n,

For finish total average throughput that user m obtains from all base stations by the end of t-1 timeslot scheduling.

Wherein, select specifically to comprise: according to formula in the step of value of indicative function the described user that t time slot is set

The user that t time slot is set selects the value of indicative function, wherein, and I _{N, m}(t) be the indicative function of choice relation between base station and user, I _{N, m}(t)=1 be illustrated in t time slot, base station n selects user m to transmit; I _{N, m}(t)=0 being illustrated in t time slot user m is not selected to transmit by base station n.

Wherein, upgrade in the step of average throughput separately, specifically comprise: to all base station n and user m, according to formula in described each base station

${\stackrel{\‾}{R}}_{n,m}\left(t\right)=\frac{t-1}{t}{\stackrel{\‾}{R}}_{n,m}(t-1)+\frac{1}{t}{r}_{n,m}\left(t\right)I_{n,m}\left(t\right).$

Average throughput is separately upgraded in each base station, wherein, n=1,2 ..., N, m=1,2 ..., M, N are the number that can carry out the base station of collaboration communication in the network, M be in the network can with the number of the user terminal of each base station communication, R _{N, m}(t) be to finish the local average throughput that user m obtains from base station n, R by the end of t timeslot scheduling _{N, m}(t-1) be to finish the local average throughput that user m obtains from base station n, r by the end of t-1 timeslot scheduling _{N, m}(t) be in t time slot, the achievable rate that base station n can provide for user m, I _{N, m}(t) be the indicative function of choice relation between base station and user.

Wherein, broadcast in the step of average throughput separately mutually in described all base stations, specifically comprise: each base station is carried out R one time every T time slot _{N, m}(t) broadcasting, R _{N, m}(t) be to finish the local average throughput that user m obtains from base station n by the end of t timeslot scheduling.

Wherein,, specifically comprise mutually in the step of broadcasting average throughput separately in described all base stations: each base station at each time slot with certain Probability p (0＜p＜1) broadcasting R separately _{N, m}(t), R _{N, m}(t) be to finish the local average throughput that user m obtains from base station n by the end of t timeslot scheduling.

Wherein, obtain each user from the step of the overall average throughput of all base stations acquisitions, specifically comprise: according to formula in described each base station

${\hat{R}}_m\left(t\right)=\underset{n=1}{\overset{N}{\mathrm{\Σ}}}{\stackrel{\‾}{R}}_{n,m}\left(t\right)$

Obtain described overall average throughput, wherein,

For finishing by the end of t timeslot scheduling, total average throughput that user m obtains from all base stations, N are the number that can carry out the base station of collaboration communication in the network, R _{N, m}(t) be to finish the local average throughput that user m obtains from base station n by the end of t timeslot scheduling

Compared with prior art, technical scheme of the present invention has following advantage:

1. the total average throughput of each user is improved.

2. the stability of the total average throughput of each user gets a promotion.

3. the fairness of total average throughput is very high between the user.

4. the present invention can complete asynchronous execution, still can guarantee good convergence in asynchronous execution, and finally converge to the average throughput identical with the global proportionality fair scheduling algorithm of standard.

Description of drawings

Fig. 1 is the network structure that a plurality of users in a kind of a plurality of base stations of prior art are transmitted simultaneously;

Fig. 2 is the flow chart of the method for scheduling global proportionality equitableness of a kind of multi-BS (base station) multi-user of the present invention;

Fig. 3 is that standard global proportionality fair scheduling algorithm of the present invention and algorithm are promoted one comparison diagram;

Fig. 4 is that standard global proportionality fair scheduling algorithm of the present invention and algorithm are promoted two comparison diagram;

Fig. 5 is the comparison diagram of throughput of the Proportional Fair algorithm of global proportionality fair scheduling algorithm of the present invention and prior art;

Fig. 6 is the comparison diagram that the throughput of the Proportional Fair algorithm of global proportionality fair scheduling algorithm of the present invention and prior art is shaken;

Fig. 7 is the throughput fairness schematic diagram of global proportionality fair scheduling algorithm of the present invention.

Embodiment

Below in conjunction with drawings and Examples, the specific embodiment of the present invention is described in further detail.Following examples are used to illustrate the present invention, but are not used for limiting the scope of the invention.

When adopting the network configuration that a plurality of users in a plurality of base stations shown in Figure 1 transmit simultaneously, the flow process of the method for scheduling global proportionality equitableness of a kind of multi-BS (base station) multi-user of the present invention may further comprise the steps as shown in Figure 2:

Step s201, at first time slot, all average throughputs of initialization.When time slot t=1,, make R to all base station n and user m _{N, m}(t)=1, wherein, n=1,2 ..., N, m=1,2 ..., M, N are the number that can carry out the base station of collaboration communication in the network, M be in the network can with the number of the user terminal of each base station communication, R _{N, m}(t) be to finish the local average throughput that user m obtains from base station n by the end of t timeslot scheduling.

Step s202 to all base stations, selects the user of each base station t slot transmission.According to formula

$m_n^{*}\left(t\right)=\underset{m=\mathrm{1,2},\·\·\·,M}{\arg \max }\frac{r_{n,m}\left(t\right)-{\stackrel{\‾}{R}}_{n,m}(t-1)}{{\hat{R}}_m(t-1)}$

Select the user of base station n t slot transmission, wherein, r _{N, m}(t) be in t time slot, the achievable rate that base station n can provide for user m, R _{N, m}(t-1) be to finish by the end of t-1 timeslot scheduling, the local average throughput that user m obtains from base station n,

For finish total average throughput that user m obtains from all base stations by the end of t-1 timeslot scheduling.

Step s203, to all base stations, the user that t time slot is set selects the value of indicative function.According to formula

The user that t time slot is set selects the value of indicative function, wherein, and I _{N, m}(t) be the indicative function of choice relation between base station and user, I _{N, m}(t)=1 be illustrated in t time slot, base station n selects user m to transmit; I _{N, m}(t)=0 being illustrated in t time slot user m is not selected to transmit by base station n.

Step s204, average throughput is separately upgraded in each base station.To all base station n and user m, according to formula

${\stackrel{\‾}{R}}_{n,m}\left(t\right)=\frac{t-1}{t}{\stackrel{\‾}{R}}_{n,m}(t-1)+\frac{1}{t}{r}_{n,m}\left(t\right)I_{n,m}\left(t\right).$

Average throughput is separately upgraded in each base station, wherein, n=1,2 ..., N, m=1,2 ..., M, N are the number that can carry out the base station of collaboration communication in the network, M be in the network can with the number of the user terminal of each base station communication, R _{N, m}(t) be to finish the local average throughput that user m obtains from base station n, R by the end of t timeslot scheduling _{N, m}(t-1) be to finish the local average throughput that user m obtains from base station n, r by the end of t-1 timeslot scheduling _{N, m}(t) be in t time slot, the achievable rate that base station n can provide for user m, I _{N, m}(t) be the indicative function of choice relation between base station and user.

Step s205, all base stations are broadcasting average throughput separately mutually, and each base station obtains the overall average throughput that each user obtains from all base stations.According to formula

${\hat{R}}_m\left(t\right)=\underset{n=1}{\overset{N}{\mathrm{\Σ}}}{\stackrel{\‾}{R}}_{n,m}\left(t\right)$

Obtain described overall average throughput, wherein,

For finishing by the end of t timeslot scheduling, total average throughput that user m obtains from all base stations, N are the number that can carry out the base station of collaboration communication in the network, R _{N, m}(t) be to finish the local average throughput that user m obtains from base station n by the end of t timeslot scheduling.

Above process is the description of global proportionality equity dispatching method, in step s205, in each time slot, after the scheduling and user throughput renewal end of each base station, the average throughput information that requires to broadcast mutually separately between all base stations is given other base station, and this step will be brought following problem:

(1) needs precise synchronization between different base station, thereby guarantee the alignment of each time slot;

(2) after the finishing scheduling of each time slot, extra communication and computing cost all will be brought to other base station broadcast in each base station;

So we promote this algorithm.

Promote one: broadcast local average throughput R every T time slot _{N, m}(t) global proportionality fair scheduling algorithm.

At first, we relax different base station and will carry out R at each time slot _{N, m}(t) Guang Bo requirement, but allow each base station to carry out R one time every T time slot _{N, m}(t) broadcasting.Emulation confirms: this popularization algorithm can converge on the result that the global proportionality fair scheduling algorithm of standard provides well.Simulation result is seen shown in Figure 3, and among this Fig. 3, the cycle that local average throughput broadcasting is carried out in all base stations is set to T=100 and T=1000.

Promote two: complete asynchronous global proportionality fair scheduling algorithm.

This promote to allow each base station at each time slot with the local throughput R of certain Probability p to other base station broadcast oneself _{N, m}(t).Emulation confirms: this popularization algorithm can well converge on the result that the global proportionality fair scheduling algorithm of standard provides.Concrete outcome is seen shown in Figure 4.In Fig. 4, each base station is set to p=0.01 and p=0.001 at the probability of the own local average throughput of each time slot broadcasting.

The present invention can be embedded in existing GSM and the TD-SCDMA network, and the key technology that also can be used as base station in the next generation communication system is used, and has the wide scope of application.

The present invention compares with Proportional Fair algorithm of the prior art, has following advantage:

(1) the total average throughput of each user is improved.

Fig. 5 has shown corresponding results.For each user, the total throughput that adopts the global proportionality fair scheduling algorithm to obtain all is higher than the total throughput that adopts local equitable proportion to obtain.

(2) stability of the total average throughput of each user gets a promotion.

The stability of total average throughput utilizes it to be measured around the amount of jitter of mean value.The amount of jitter δ of total average throughput _m(t) be defined as follows:

${\mathrm{\δ}}_m\left(t\right)=\frac{1}{t}\underset{\mathrm{\τ}=1}{\overset{t}{\mathrm{\Σ}}}{\left[\frac{{\mathrm{\Σ}}_{n=1}^N{r}_{n,m}\left(\mathrm{\τ}\right)I_{n,m}\left(\mathrm{\τ}\right)-{\hat{R}}_m\left(\mathrm{\τ}\right)}{{\hat{R}}_m\left(\mathrm{\τ}\right)}\right]}^2$

$=\frac{t-1}{t}{\mathrm{\δ}}_m(t-1)+\frac{1}{t}{\left[\frac{{\mathrm{\Σ}}_{n=1}^N{r}_{n,m}\left(t\right)I_{n,m}\left(t\right)-{\hat{R}}_m\left(t\right)}{{\hat{R}}_m\left(t\right)}\right]}^2$

The result of Fig. 6 shows: for each user, the total throughput amount of jitter that adopts the global proportionality fair scheduling algorithm to obtain all is lower than the result who adopts local equitable proportion to obtain, this means that each user can obtain more stable service speed, guarantee the service quality of system.

(3) fairness of total average throughput is very high between the user.

The present invention weighs the fairness of the total average throughput of each user with Jain fairness coefficient, and this fairness coefficient is defined as follows, to one group of data x ₁, x ₂..., x _M, its Jain fairness coefficient is:

$f(x_1,x_2,....x_M)=\frac{{\left({\mathrm{\Σ}}_{i=1}^M{x}_i\right)}^2}{M{\mathrm{\Σ}}_{i=1}^M{x}_i^2}$

This coefficient approaches 1 more, shows that the fairness between these group data is high more, otherwise, illustrate that the fairness of these group data is low more.Fig. 7 result shows that the fairness coefficient of throughput extremely approaches 1 between the user that the present invention causes, and illustrates that the present invention can guarantee well that different user obtains fair relatively throughput distribution.

(4) the present invention can complete asynchronous execution, still can guarantee good convergence in asynchronous execution, and finally converge to the average throughput identical with the global proportionality fair scheduling algorithm of standard.

The present invention is mainly used in the base station end in the next generation mobile communication system, both can this algorithm be solidificated in peripheral chip or the embedded system with the form of hardware, utilize bus structures to be configured on the existing base station server, make the local average throughput information that can offer each user between different base station alternately, finish from of the evolution of current mobile communication system to next generation mobile communication system.On the other hand, the present invention can realize with the form of software again, and this software is installed on base station server of future generation, utilizes the communication function of base station of future generation self, carries out the global proportionality fair scheduling algorithm.

The present invention only requires at the base station end and carries out hardware configuration or software installation, to the requirement of user terminal without any execution mode, can be used with second generation portable terminal, also can support the third generation or following mobile communication terminal, improve the throughput of user terminal and the guarantee of certain service fairness is provided.

The above only is a preferred implementation of the present invention; should be pointed out that for those skilled in the art, under the prerequisite that does not break away from the technology of the present invention principle; can also make some improvements and modifications, these improvements and modifications also should be considered as protection scope of the present invention.

Claims (8)

1, a kind of method for scheduling global proportionality equitableness of multi-BS (base station) multi-user is characterized in that, said method comprising the steps of:

At first time slot, all average throughputs of initialization;

To all base stations, select the user of each base station in same time slot t transmission;

To all base stations, the user that described time slot t is set selects the value of indicative function;

Average throughput is separately upgraded in each base station;

All base stations are broadcasting average throughput separately mutually;

Each base station obtains the overall average throughput that each user obtains from all base stations.

2, the method for scheduling global proportionality equitableness of multi-BS (base station) multi-user according to claim 1 is characterized in that, in the step of described all average throughputs of initialization, specifically comprises:

When time slot t=1,, make R to all base station n and user m _{N, m}(t)=1, wherein, n=1,2 ..., N, m=1,2 ..., M, N are the number that can carry out the base station of collaboration communication in the network, M be in the network can with the number of the user terminal of each base station communication, R _{N, m}(t) be to finish the local average throughput that user m obtains from base station n by the end of t timeslot scheduling.

3, as the method for scheduling global proportionality equitableness of multi-BS (base station) multi-user as described in the claim 2, it is characterized in that, in the user's of t slot transmission step, specifically comprise in each base station of described selection:

According to formula

$m_n^{*}\left(t\right)=\underset{m=\mathrm{1,2},\·\·\·,M}{\arg \max }\frac{r_{n,m}\left(t\right)-{\stackrel{\‾}{R}}_{n,m}(t-1)}{{\hat{R}}_m(t-1)}$

Select the user of base station n t slot transmission, wherein, r _{N, m}(t) be in t time slot, the achievable rate that base station n can provide for user m, R _{N, m}(t-1) be to finish by the end of t-1 timeslot scheduling, the local average throughput that user m obtains from base station n,

For finish total average throughput that user m obtains from all base stations by the end of t-1 timeslot scheduling.

4, as the method for scheduling global proportionality equitableness of multi-BS (base station) multi-user as described in the claim 3, it is characterized in that, select specifically to comprise in the step of value of indicative function the described user that t time slot is set:

According to formula

The user that t time slot is set selects the value of indicative function, wherein, and I _{N, m}(t) be the indicative function of choice relation between base station and user, I _{N, m}(t)=1 be illustrated in t time slot, base station n selects user m to transmit; I _{N, m}(t)=0 being illustrated in t time slot user m is not selected to transmit by base station n.

5, as the method for scheduling global proportionality equitableness of multi-BS (base station) multi-user as described in the claim 4, it is characterized in that, upgrade in the step of average throughput separately, specifically comprise in described each base station:

To all base station n and user m, according to formula

${\stackrel{\‾}{R}}_{n,m}\left(t\right)=\frac{t-1}{t}{\stackrel{\‾}{R}}_{n,m}(t-1)+\frac{1}{t}{r}_{n,m}\left(t\right)I_{n,m}\left(t\right).$

Average throughput is separately upgraded in each base station, wherein, n=1,2 ..., N, m=1,2 ..., M, N are the number that can carry out the base station of collaboration communication in the network, M be in the network can with the number of the user terminal of each base station communication, R _{N, m}(t) be to finish the local average throughput that user m obtains from base station n, R by the end of t timeslot scheduling _{N, m}(t-1) be to finish the local average throughput that user m obtains from base station n, r by the end of t-1 timeslot scheduling _{N, m}(t) be in t time slot, the achievable rate that base station n can provide for user m, I _{N, m}(t) be the indicative function of choice relation between base station and user.

6, as the method for scheduling global proportionality equitableness of multi-BS (base station) multi-user as described in the claim 5, it is characterized in that, mutually in the step of broadcasting average throughput separately, specifically comprise in described all base stations:

Each base station is carried out R one time every T time slot _{N, m}(t) broadcasting, R _{N, m}(t) be to finish the local average throughput that user m obtains from base station n by the end of t timeslot scheduling.

7, as the method for scheduling global proportionality equitableness of multi-BS (base station) multi-user as described in the claim 5, it is characterized in that, mutually in the step of broadcasting average throughput separately, specifically comprise in described all base stations:

Each base station at each time slot with certain Probability p broadcasting R separately _{N, m}(t), R _{N, m}(t) be to finish the local average throughput that user m obtains from base station n by the end of t timeslot scheduling.

8, as the method for scheduling global proportionality equitableness of multi-BS (base station) multi-user as described in claim 6 or 7, it is characterized in that, obtain the step of the overall average throughput that each user obtains from all base stations, specifically comprise in described each base station:

According to formula

${\hat{R}}_m\left(t\right)=\underset{n=1}{\overset{N}{\mathrm{\Σ}}}{\stackrel{\‾}{R}}_{n,m}\left(t\right)$

Obtain described overall average throughput, wherein, For finishing by the end of t timeslot scheduling, total average throughput that user m obtains from all base stations, N are the number that can carry out the base station of collaboration communication in the network, R _{N, m}(t) be to finish the local average throughput that user m obtains from base station n by the end of t timeslot scheduling.

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