CN1283121C - Resource allocation method and apparatus in wireless communication system - Google Patents

Abstract

The present invention discloses a method for distributing channel resources in a radio communication system. The radio communication system comprises an access point and a plurality of user terminals. The method comprises the following procedures that a request message is received from each user terminal among a plurality of user terminals, and the request message comprises a business transmission rate requested on each sub-channel by each user terminal among a plurality of user terminals and a transmission rate which is already distributed to each user terminal so as to calculate the ratio of the business transmission rate requested on each sub-channel by each user terminal and the transmission rate which is already distributed to each user terminal; a corresponding user terminal with the maximum ratio is determined according to the ratio; in addition, the user terminal with the maximum ratio is invoked in the next transmission period. The throughput of the entire system is increased on the basis that different rate requests of each user terminal are satisfied according to the method of the present invention.

Description

Resource allocation methods in the wireless communication system and equipment

Technical field

The present invention relates to the resource allocation in the wireless communication system, particularly channel resource allocation method in the wireless communication system and equipment.

Background technology

Along with high speed development such as internet, Email, multimedia etc., for data service require growing.In order to support these Packet data services, must utilize finite wireless resources in the mode of the best, with increase capacity and guarantee service quality (QoS).How to guarantee the priority and the fairness of different business, extremely important for the channel resource allocation of wireless communication system.

In existing C DMA system, following several scheduling of resource mode is arranged:

A. maximum C/I scheduling, just scheduler selects to have the user terminal of the highest moment C/I.This scheduling mode is very simple, and it only carries out Resources allocation according to the gain of subchannel, and it does not consider the requirement of any fairness.The performance gain of maximum C/I dispatching method can be regarded as the upper limit of the performance that dynamic resource scheduling can obtain.

B. circulation (round-robin) scheduling, just scheduler selects maximum duration not obtain the user terminal of serving, and compares with maximum C/I scheduling mode, and the round-robin scheduling method is distributed to each user terminal with Channel Elements by the mode of poll.The life of round-robin scheduling method because being equivalent to fixed resource in fact, the resource allocation of round-robin scheduling method distributes, so can be regarded as the performance lower limit of Dynamic Resource Allocation for Multimedia algorithm.

C. equitable proportion (Proportional Fairness, PF) scheduling, the PF dispatching method of using in wireless communication system can be expressed as follows:

$s\left(n\right)=\arg \underset{i}{\max }\frac{{\mathrm{DRC}}_i\left(n\right)}{R_i\left(n\right)},---\left(1\right)$

Here, $R_i\left(n\right)=(1-\frac{1}{n})R_i(n-1)+\frac{1}{n}{\mathrm{DRC}}_i^{\mathrm{assigned}}\left(n\right);$ N is Transmission Time Interval (TTI) index number; I is the user terminal call number.DRC _i ⁽ⁿ⁾Be the application speed of i user terminal on n TTI.Proportional fair dispatching method is considered the fairness and the validity of system, but does not consider the qos requirement of each user terminal.

D. dynamic object (DTM) scheduling that has maximum/minimum-rate, disclose this DTM dispatching method at ChingYaoHuang and HueiYuan Su in " Schedulers for1xEV-DO:third generation wireless high speed data SyStems " literary composition of delivering spring in 2003, this literary composition is incorporated the present invention into as a reference.This DTM dispatching method be to the PF method improvement, its available following formulate:

$S\left(n\right)=\arg \underset{i}{\max }\frac{{\mathrm{DRC}}_i\left(n\right)}{R_i\left(n\right)}*F_i\left(n\right)$

Wherein

$F_i\left(n\right)=F_i(n-1)+\frac{F_i^d\left(n\right)}{M},$

$F_i^d\left(n\right)=\left\{\begin{array}{cc}-e^{(R_i\left(n\right)-R_{\max })},& R_{\max }<R_i\left(n\right)\\ -(R_i\left(n\right)-R_{\mathrm{Di}\arg \mathrm{et}}),& R_{\mathrm{Di}\arg \mathrm{et}}<R_i\left(n\right)<R_{\max }\\ -(R_i\left(n\right)-R_{\mathrm{Di}\arg \mathrm{et}}),& R_{\min }<R_i\left(n\right)<R_{\mathrm{Di}\arg \mathrm{et}}\\ e^{(R_{\min }-R_i\left(n\right))},& R_i\left(n\right)<R_{\min }\end{array}\right.,$

Wherein $R_{\mathrm{Di}\arg \mathrm{et}}\left(n\right)=\frac{\underset{i}{\mathrm{\&Sigma;}}{R}_i\left(n\right)}{N}.$

DRC wherein _i(n) and R _i(n) identical with implication in the formula (1), F _i(n) be the weighted factor of i user terminal, R _MaxAnd R _MinThe minimum and maximum throughput of expression user terminal, M is a variable, is used to represent come from the rank of the control of DTM, N is within a certain period of time the quantity of validated user terminal in the system.

The DTM dispatching method is the dispatching method that is applicable to single-channel system, and it is the scheduling on time shaft only, and it can not be dispatched at multichannel system, just can not carry out the bidimensional scheduling on time shaft and frequency axis.

In addition, the purpose of DTM dispatching method is to allow final rate distribution within a predetermined minimax scope, rather than, therefore, can not on the basis of satisfying each user terminal different rates request, promote the throughput of whole system at the QoS rate request of each user terminal.

Therefore, in wireless communication system, need a kind of new channel resource allocation method and device, be used for liberally and the resource of scheduling wireless communications system effectively, and allow each user terminal to specify different minimum request rates.

Summary of the invention

Therefore, the object of the present invention is to provide a kind of can be liberally and the resource in the scheduling wireless communications system effectively, and allow each user terminal to specify the channel resource allocation method of different minimum request rates.

According to the present invention, above-mentioned purpose is by providing a kind of method of carrying out resource allocation in wireless communication system to realize, described wireless communication system comprises access point and a plurality of user terminal, described method comprises the following steps: each the reception request message from described a plurality of user terminals, described request message comprises each service transmission rate of being asked of described a plurality of user terminals and the transmission rate of having distributed to each user terminal on each subchannel, to calculate the ratio of described each user terminal between service transmission rate of being asked on each subchannel and the transmission rate of having distributed to each user terminal; Be used for according to described ratio, determine to have the pairing user terminal of maximum ratio; And, between next transmission period, call described user terminal with described maximum ratio.

Another object of the present invention is to provides the equipment that carries out resource allocation in a kind of wireless communication system efficiently, is used for liberally and the resource of scheduling wireless communications system effectively, and allows each user terminal to specify different minimum request rates.

According to the present invention, above-mentioned purpose is to realize by a kind of equipment that is used for carrying out at wireless communication system resource allocation, described wireless communication system comprises access point and a plurality of user terminal, described equipment comprises: calculation element, each that is used for from described a plurality of user terminals receives request message, described request message comprises each service transmission rate of being asked of described a plurality of user terminals and the transmission rate of having distributed to each user terminal on each subchannel, to calculate the ratio of described each user terminal between service transmission rate of being asked on each subchannel and the transmission rate of having distributed to each user terminal; Determine device, be used for, determine to have the pairing user terminal of maximum ratio according to described ratio; And scheduler is used between next transmission period, calls the described user terminal with described maximum ratio.

The description of execution mode and accompanying drawing by the back, it is clearer that the other objects and features of the invention will become.Identical label is represented same or analogous parts in the accompanying drawing.

Description of drawings

Quote and the accompanying drawing of forming a specification part shows embodiments of the present invention at this, and be used to explain principle of the present invention in conjunction with declaratives.

Fig. 1 shows the wireless communication system that comprises channel resource allocation equipment of the present invention;

Fig. 2 shows the channel resource allocation equipment according to one embodiment of the present invention;

Fig. 3 is a schematic diagram, shows the resource allocation of the temporal frequency unit in ofdm system;

Fig. 4 shows the channel resource allocation equipment according to another embodiment of the present invention;

Fig. 5 shows the model of an emulation wireless communication system;

Fig. 6 is a schematic diagram, shows the performance of maximum C/I dispatching method;

Fig. 7 is a schematic diagram, shows the performance of round-robin scheduling method;

Fig. 8 is a schematic diagram, shows the performance of proportional fair dispatching method;

Fig. 9 is a schematic diagram, shows the performance of the dispatching method according to the present invention;

Figure 10 is a schematic diagram, shows the fairness and the validity curve of dispatching method of the present invention under the different situations; And

Figure 11 is a schematic diagram, shows the efficiency curve of dispatching method of the present invention under different situations.

Embodiment

Below in conjunction with accompanying drawing, preferred implementation of the present invention is described in detail.

Fig. 1 shows a kind of wireless communication system, and this wireless communication system comprises an access point 100 and a network controller 200.In addition, this wireless communication system also comprises a plurality of user terminals 300.Access point 100 is connected to network controller 200 by for example transmission network.Access point 100 calls different user terminal 300 according to certain rule, to set up communication link in the different time under the control of network controller 200.

Fig. 2 shows a kind of channel resource allocation equipment according to wireless communication system shown in the Fig. 1 of can be used for of the present invention.In fact, this channel resource allocation equipment is arranged in access point 100 or network controller 200.With regard to its effect, this channel resource allocation equipment is used for judging within a certain period of time according to coming from the report message of different user terminals, calls which user terminal and is used for next time transmission.

Referring to Fig. 2, channel resource allocation equipment according to the present invention comprises calculation element 210, determines device 230 and scheduler 250.Present embodiment is that example is described with OFDM (OFDM) system, but the present invention is not limited to this.

The scheduling of resource of ofdm system comes down to the scheduling on time, the frequency bidimensional resource.A basic temporal frequency scheduling unit (TFU) may be a subchannel on the Transmission Time Interval (TTI) in the system, as shown in Figure 3.

As can be seen from Figure 3, different user terminal has the requirement of different message transmission rates on different subchannels.Based on the two dimensional nature of OFDM scheduling of resource, to consider the fairness and the validity of resource allocation according to the dispatching method of present embodiment, to take into account of the requirement of each user terminal simultaneously to QoS.

Below with reference to Fig. 2, specifically describe operation principle according to channel resource allocation equipment of the present invention.

At first, the calculation element 210 of channel resource allocation equipment receives the request message that comes from a plurality of user terminals 300, and this request message comprises each institute's requested service transmission rate (DRC on each subchannel of a plurality of user terminals 300 _{I, j}) and up to the present to the transmission rate (R that distributes to each user terminal _i(n)), DRC wherein _{I, j}Expression is the rate request of i user terminal on j subchannel, R _i(n) speed of user terminal i is distributed in expression till current time slots.Calculation element 210 calculates the ratio of the transmission rate that each user terminal institute's requested service transmission rate and corresponding former each user terminal on each subchannel distributed, i.e. DRC _{I, j}/ R _i(n).

Then, be connected to definite device 230 of calculation element 210, the ratio DRC of the transmission rate of having distributed according to calculation element 210 resultant each user terminals institute's requested service transmission rate and corresponding former each user terminal on each subchannel _{I, j}/ R _i(n), therefrom choose its ratio maximum, and determine at the pairing user terminal of this maximum ratio.

Behind definite pairing user terminal of above-mentioned maximum, just have the user terminal of highest priority after, scheduler 250 according to the present invention is dispatched this user terminal between next transmission period.

Said process can pass through formula (2) expression:

$P_{i,j}\left(n\right)=\arg \underset{i}{\max }\frac{{\mathrm{DRC}}_{i,j}\left(n\right)}{R_i\left(n\right)}---\left(2\right)$

Wherein $R_i\left(n\right)=(1-\frac{1}{n})R_i(n-1)+\frac{1}{n}{\mathrm{DRC}}_i^{\mathrm{assigned}}\left(n\right)---\left(3\right)$

In expression formula (2), R _i(n) be the speed of till current time slots, distributing to user terminal i; p _{I, j}Be the dispatching priority of i user terminal on j subchannel.I, j are respectively that user terminal call number and sub-channel index .n are the call numbers of TTI; DRC _{I, j}Be the rate request of i user terminal on j subchannel.

Below with reference to Fig. 4, another execution mode according to the channel resource allocation equipment of wireless communication system shown in the Fig. 1 of can be used for of the present invention is described.

Referring to Fig. 4, except that comprising calculation element 210, determine also to comprise phase quadrupler 260 and weighting device 220 outside device 230 and the scheduler 250 according to channel resource allocation equipment of the present invention.In the present embodiment, be that example is described still, but the present invention is not limited to this with OFDM (OFDM) system.

Below with reference to Fig. 4, specifically describe operation principle according to the channel resource allocation equipment of present embodiment.

At first, the calculation element 210 of channel resource allocation equipment receives the request message that comes from a plurality of user terminals 300, and this request message comprises each institute's requested service transmission rate (DRC on each subchannel of a plurality of user terminals 300 _{I, j}) and be to the transmission rate (R that distributes to each user terminal up till now _i(n)), DRC wherein _{I, j}Expression is the rate request of i user terminal on j subchannel, R _i(n) speed of user terminal i is distributed in expression till current time slots.Calculation element 210 calculates the ratio of the transmission rate that each user terminal institute's requested service transmission rate and corresponding former each user terminal on each subchannel distributed, i.e. DRC _{I, j}/ R _i(n).

In the present embodiment, channel resource allocation equipment also comprises a weighting device 220, is used to produce weight coefficient W _i(n), each ratio that calculation element 210 is exported is weighted, and the result after the weighting is passed through phase quadrupler 260, outputs to and determines device 230.

Then, be connected to definite device 230 of calculation element 210, according to the ratio DRC of calculation element 210 resultant each user terminals between the transmission rate that institute's requested service transmission rate on each subchannel and corresponding former each user terminal have distributed _{I, j}/ R _i(n) and corresponding weight coefficient W _i(n), therefrom choose ratio and be weighted a maximum numerical value of back, and determine the pairing user terminal of this greatest measure.

Behind definite pairing user terminal of above-mentioned maximum, just have the user terminal of highest priority after, scheduler 250 according to the present invention is dispatched this user terminal between next transmission period.

Said process can pass through formula (4) expression:

$P_{i,j}\left(n\right)=\arg \underset{i}{\max }\frac{{\mathrm{DRC}}_{i,j}\left(n\right)}{R_i}{\&CenterDot;W}_j\left(n\right)---\left(4\right)$

Wherein $R_i\left(n\right)=(1-\frac{1}{n})R_i(n-1)+\frac{1}{n}{\mathrm{DRC}}_i^{\mathrm{assigned}}\left(n\right);$

$W_i\left(n\right)=\exp (\frac{{\mathrm{Rb}}_i-{\mathrm{Rf}}_i\left(n\right)}{{\mathrm{Rb}}_i}\&CenterDot;\frac{1}{M})---\left(5\right)$

${\mathrm{Rf}}_i\left(n\right)={\mathrm{Rf}}_i\left(n\right)+{\mathrm{DRC}}_{(i,j)}^{\mathrm{assigned}}\left(n\right)---\left(6\right)$

In expression formula (4), Rb _iRepresent the service request speed of i user terminal; R _i(n) be the speed of till current time slots, distributing to user terminal i; p _{I, j}Be the dispatching priority of i user terminal on j subchannel.I, j are respectively user terminal call number and sub-channel index number.N is the call number of TTI; DRC _{I, j}Be the rate request of i user terminal on j subchannel.Rf _iBe the tolerance of the rate-allocation of user terminal i in a TTI; Having after new sub channel resource distributes to user terminal i, it can upgrade according to formula (6) at every turn.M is a variant variables, is used to characterize the degree of convergence according to the inventive method.M gets different values, and method of the present invention will have different convergence dynamics, and causes different performances.Weight coefficient W _iBe that the instantaneous distribution speed that obtains with user terminal and the difference of QoS rate requirement are the exponential function of independent variable.(Rb when the QoS of user terminal rate request is not satisfied as yet _i＞Rf _i), W _iTo therefore improve the dispatching priority of this user terminal greater than 1; (Rb when the QoS of user terminal rate request has been satisfied _i＜Rf _i), weight coefficient W _iTo this means the terminal i for the active user less than 1, its dispatching priority will be lower than other priority that do not satisfy user terminal.

Below by a wireless communication system, come relatively and verify the performance of additive method in the method according to this invention and the prior art.

Fig. 5 shows an emulation wireless communication system.This wireless communication system comprises an access point (AP) and a plurality of portable terminal (MT).Here, we choose an AP and 16 equally distributed MT in the sub-district.Each MT has its oneself qos requirement, supposes that the summation of the rate request of all user terminals is no more than total transmittability of system.

For example, we consider the QoS rate request of each following user terminal: [0.8,0.1,0.8,0.2,1.0,0.1,1.0,0.1,0.8,2,0.2,0.8,0.2,1.0,0.1,0.8]. the model of wireless communication system is as shown in Figure 5.The decline of the air interface that each MT experienced is by obeys index distribution, and parameter is that 4 path loss, standard deviation are formed by 8 logarithm shadow fading and multipath Rayleigh decline.Each MT estimates and determines corresponding transmission rate (can be quantified as index sequence, i.e. drc signal) to the own quality of wireless channel that is experienced.The drc signal of each user terminal will periodically be fed back to AP and carry out sub channel resource by AP and distribute.At receiving terminal, the speed and the throughput of each user terminal will be calculated.

For realizing said system, in data transmission procedure, we suppose the mode that adopts the endless buffering, promptly after connecting foundation transfer of data are arranged all the time.In order to improve the validity of system, we have adopted the adaptive modulation and coding technology.Concrete adaptive modulation and coding scheme is as shown in table 1:

Table 1

The MT index	Modulation system	Encoding rate	Exchange SNR threshold value (dB)	Channel bit rate (Mbps)
					?1	?BPSK	?1/4	---	?1.68
?2	?BPSK	?1/2	7	?3.36
					?3	?QPSK	?1/2	10	?6.72
?4	?QPSK	?3/4	15	?10.88
					?5	?8PSK	?2/3	17	?13.44
?6	?16QAM	?3/4	21	?20.16
					?7	?64QAM	?2/3	24.8	?26.88

For the measurement of fairness and validity, we use following two parameters.The fairness coefficient may be defined as: $\mathrm{FC}=\frac{1}{1+V},$ Wherein V is the variance of each user terminal throughput; The validity coefficient may be defined as: $\mathrm{\&eta;}=\frac{M_{\mathrm{thr}}}{S_{\max }}$ M wherein _ThrBe the average of each user terminal throughput and S _MaxIt is the maximum of the throughput of system that can provide in the Adaptive Modulation and Coding scheme.According to this definition, the value of FC should be between 0 (unfairness) and 1 (the most fair). and η represents validity, and higher η value also just means the higher system throughput.

By relatively, can understand the performance of each resource regulating method earlier; Then, can further understand the method according to this invention.

Fig. 6 has shown the performance of different dispatching methods to Fig. 9.In Fig. 9, (a) show the QoS rate requirement of each user terminal at Fig. 6; (b) show the normalization result that TFU distributes; (c) speed that shows each user terminal and distributed; (d) show the throughput of each user terminal.

As can be seen, use different dispatching methods from Fig. 6 to Fig. 9, the performance of its generation also has very big difference.

Table 2 shows the comparison of various dispatching methods:

Table 2

Scheduling mode	Cell throughout and good output (Mbps)	Minimum and maximum user terminal speed (Mbps)	FC	η	Is QoS satisfied?
						Max?C/I	(26.8799， 26.7432)	(21.1805， 0.0000)	0.0337	?0.9949	---
Round-robin method	(15.8756，15.5990)	(1.6666， 0.3365)	0.8144	?0.5803	---
						PF	(21.3918， 20.8984)	(1.7748， 0.6215)	0.8171	?0.7774	---
Method of the present invention	(20.1180， 19.7052)	(2.6363， 0.3821)	(0.9002 mean F C)	?0.7330	Be

As can be seen from Table 2, most effective (η=0.9949) of maximum C/I dispatching method, but its fairness is also the poorest, just has a plurality of user terminals not to be assigned to any resource.In contrast, better (FC=0.8144) but efficient minimum (η=0.5803) of the fairness of round-robin scheduling method.

Simultaneously as can be seen, the PF dispatching method expanded in the ofdm system also can obtain preferable performance, its validity and fairness are respectively η=0.7774 and FC=0.8171.This is because the scheduling mode of ofdm system bidimensional obtains preferable performance for PF algorithm more freedom degree and space.

Fig. 9 has provided the performance of dispatching method of the present invention when M=3.0.This figure shows that dispatching method of the present invention at first can satisfy the qos requirement (each user terminal has all been distributed to more than or equal to its QoS rate request) of each user terminal.For the measurement of the fairness of method of the present invention, slightly different with the narration of front.Because given QoS rate request has in fact also just determined the FC value of an inherence, thereby as long as method of the present invention converges to the QoS speed of expectation, all should be near this FC value according to the fairness coefficient that above-mentioned method is calculated.

For accurately weighing the fairness of dispatching method of the present invention, we consider to have the user terminal grouping of identical QoS request rate (such as being divided into N child user group, user terminal number of each son group may be identical also may be different, but each user's QoS is all identical in each son group) and in this group according to before method investigate fairness.

Here can define $\mathrm{Sub}\_\mathrm{FC}=\frac{1.0}{1+\mathrm{var}\left({\mathrm{thr}}_{\mathrm{user}\_\mathrm{group}}\right)}$ With $\mathrm{Average}\_\mathrm{FC}=\frac{1}{N}\underset{i=1}{\overset{N}{\mathrm{\&Sigma;}}}\mathrm{Sub}\_{\mathrm{FC}}_i$ (thr _{User_group}It is an one-dimension array, represent the throughput of certain child user group, the variance computing is asked in function var () representative, Sub_FC represents the fairness coefficient of certain child user group, the Average_FC of back to all, the fairness coefficient of N user group asks on average, also just obtained the average fairness coefficient of interior all user terminals of whole system).For example, user terminal (1,3,9,12,16) all has common QoS request rate---0.8Mbps, their rate-allocation and throughput are respectively (1.1874,0.9852,0.8598,1.7676,1.9176) Mbps and (1,1442,0.9448,0.8206,1.7098,1.8977) Mbps.

Therefore, the fairness coefficient between these five user terminals be Sub-FC=0.8154. in like manner, also can determine other targeted rate is 0.1Mbps, the fairness between the user terminal group of 0.2Mbps and 1.0Mbps.Their sub-fairness coefficient is respectively: 0.9622,0.9797,0.8436.Thus, the average fair coefficient that can obtain dispatching method of the present invention is: 0.9002.

It can also be seen that in table 2 maximum C/I dispatching method is compared with the round-robin scheduling method, its throughput of system has promoted 54.5%.Simultaneously, can find that also fairness that the round-robin scheduling method provides is not necessarily best.Reason is that the round-robin scheduling method is a target so that TFU is distributed to each user terminal uniformly only, and the adaptive coding modulation of enabling in the system will be taked different transmission plans according to different subchannel quality.Top result shows that PF dispatching method and dispatching method of the present invention all can provide fairness and validity preferably, but has only dispatching method of the present invention can satisfy the request of different user terminals QoS fully.

In dispatching method of the present invention, M is a very important parameter, and as previously mentioned, different M values will cause different algorithmic statement dynamics.Fairness and validity curve in Figure 10, have been provided for the dispatching method of the present invention of different M values.

Can see that along with the M value is big more, the efficient of dispatching method of the present invention is high more.Work as M=1000, the performance of dispatching method of the present invention approaches the PF algorithm.In addition, we give the throughput of user terminal and the root MSE curve of QoS request.The increase of M value will cause MSE also increasing.Can verify that in above-mentioned wireless communication system model for current QoS request, when M＞4.0 (root MSE is near 0.36), dispatching method of the present invention can not satisfy predetermined QoS targeted rate.

Nethermost curve shows among Figure 10 with different M values, the gain ratio that dispatching method of the present invention obtains from Dynamic Resource Allocation for Multimedia (system gain with maximum C/I is a denominator).Can see that M is big more, dispatching method of the present invention can be just many more from the benefit that Dynamic Resource Allocation for Multimedia obtains.Work as M=3.0, dispatching method of the present invention can reach the 38%DRA gain.Work as M=1000, when the performance of dispatching method of the present invention approached the PF algorithm, it can obtain 47% throughput gain.

The following describes dispatching method according to the present invention is how to determine parameter M's.

Dispatching method of the present invention has provided the dispatching algorithm of a kind of giving consideration to channel quality and user terminal qos requirement.Wherein, undetermined parameter M has considerable influence to the performance of algorithm.To the qos requirement of any one group of user terminal, all exist a suitable M value to make dispatching method of the present invention set up.Provide definite method of M below.

A. initialization.QoS rate request (Rb with user terminal _i) represent with Mbps unit.Service rate as i user terminal is 500kbps, then Rb _i=0.5Mbps.In dispatching method emulation of the present invention, R _f, R _iIsoparametric value all is unit with Mbps.The initial value of setting M is 1.0;

B. will carry out procedure simulation in the M value substitution dispatching method of the present invention, the throughput of each user terminal after obtaining dispatching.

C. the scheduling rates that obtains is compared with the request rate Rb of user terminal, whether checking satisfies the request rate of user terminal.If satisfy, M=M+ Δ M then, wherein Δ M is an incremental step, decides according to the size of the number range in the reality.(usually Δ M gets the positive integer less than 10) if do not satisfy, then M=M-Δ M and repeating step b.

D. the value with M increases, and the proportional gain of the dynamic dispatching that dispatching method of the present invention obtains is also big more.So the value of M should make the speed after dispatching satisfy the request rate of user terminal, makes that again the proportional gain of dynamic dispatching is big as much as possible.Repeating step b and c, can make scheduling rates satisfy in all possible value of M of user terminal speed maximum M value be ask.

Figure 11 has provided the efficiency curve of dispatching method of the present invention with different M values.We can find, between the efficient of dispatching method of the present invention and MSE a compromise are arranged, and will choose suitable M value for different QoS requests and make the requirement that can satisfy QoS can reach the efficient of maximum again.

Believe that operation of the present invention and structure are very clear by top description.Do not depart from the scope of the present invention and conceive and to make many other changes and remodeling.Should be appreciated that to the invention is not restricted to certain embodiments, scope of the present invention is defined by the following claims.

Claims (11)

1. method that is used for carrying out channel resource allocation at wireless communication system, described wireless communication system comprises access point and a plurality of user terminal, described method comprises the following steps:

Each reception request message from described a plurality of user terminals, described request message comprises each service transmission rate of being asked of described a plurality of user terminals and the transmission rate of having distributed to each user terminal on each subchannel, to calculate the ratio of described each user terminal between service transmission rate of being asked on each subchannel and the transmission rate of having distributed to each user terminal;

According to described ratio, determine to have the pairing user terminal of maximum ratio; And

Between next transmission period, call described user terminal with described maximum ratio.

2. the method that is used for carrying out at wireless communication system channel resource allocation according to claim 1 is characterized in that, also comprises step:

Service transmission rate according to user terminal requests produces the particular weights coefficient with the transmission rate of distributing to described user terminal, so that described ratio is weighted; And

Select described ratio to be weighted a maximum numerical value of back, and determine the pairing user terminal of this greatest measure.

3. the method that is used for carrying out at wireless communication system channel resource allocation according to claim 1 is characterized in that, adopts following formula to determine the user terminal that will dispatch between next transmission period:

$P_{i,j}\left(n\right)=\arg \underset{i}{\max }\frac{{\mathrm{DRC}}_{i,j}\left(n\right)}{R_i\left(n\right)}$

Wherein

$R_i\left(n\right)=(1-\frac{1}{n})R_i(n-1)+\frac{1}{n}{\mathrm{DRC}}_i^{\mathrm{assigned}}\left(n\right)$

In expression formula, R _i(n) be the speed of till current time slots, distributing to user terminal i; p _{I, j}Be the dispatching priority of i user terminal on j subchannel, i, j are respectively user terminal call number and sub-channel index number, and n is the call number of Transmission Time Interval; DRC _{I, j}Be the rate request of i user terminal on j subchannel; DRC _i ^Assigned(n) being is the rate increment that i user terminal distributes on Transmission Time Interval n; $\arg \underset{i}{\max }=\frac{{\mathrm{DRC}}_{i,j}\left(n\right)}{R_i\left(n\right)}$ Be ratio $\frac{{\mathrm{DRC}}_{i,j}\left(n\right)}{R_i\left(n\right)}$ User terminal call number when maximum.

4. the method that is used for carrying out at wireless communication system channel resource allocation according to claim 2 is characterized in that, adopts following formula to determine the user terminal that will dispatch between next transmission period:

$P_{i,j}\left(n\right)=\arg \underset{i}{\max }\frac{{\mathrm{DRC}}_{i,j}\left(n\right)}{R_i\left(n\right)}{\&CenterDot;W}_i\left(n\right)$

Wherein

$R_i\left(n\right)=(1-\frac{1}{n})R_i(n-1)+\frac{1}{n}{\mathrm{DRC}}_i^{\mathrm{assigned}}\left(n\right);$

$W_i\left(n\right)=\exp (\frac{{\mathrm{Rb}}_i-{\mathrm{Rf}}_i\left(n\right)}{{\mathrm{Rb}}_i}\&CenterDot;\frac{1}{M})$

${\mathrm{Rf}}_i\left(n\right)={\mathrm{Rf}}_i\left(n\right)+{\mathrm{DRC}}_{(i,j)}^{\mathrm{assigned}}\left(n\right)$

In expression formula, Rb _iRepresent the service request speed of i user terminal; R _i ⁽ⁿ⁾Be the speed of till current time slots, distributing to user terminal i; p _{I, j}Be the dispatching priority of i user terminal on j subchannel, i, j are respectively user terminal call number and sub-channel index number, and n is the call number of Transmission Time Interval; DRC _{I, j}Be the rate request of i user terminal on j subchannel.Rf _iBe the tolerance of the rate-allocation of user terminal i in a Transmission Time Interval; M is a variant variables, is used to characterize the degree of convergence according to the inventive method, weight coefficient W _iBe that the instantaneous distribution speed that obtains with user terminal and the difference of QoS rate requirement are the exponential function of independent variable.DRC _i ^Assigned(n) being is the rate increment that i user terminal distributes on Transmission Time Interval n, DRC _{(i, j)} ^Assigned(n) being is i the rate increment that user terminal distributes on j subchannel on Transmission Time Interval n, $\arg \underset{i}{\max }\frac{{\mathrm{DRC}}_{i,j}\left(n\right)}{R_i\left(n\right)}$ Be ratio $\frac{{\mathrm{DRC}}_{i,j}\left(n\right)}{R_i\left(n\right)}$ User terminal call number when maximum.

5. the method that is used for carrying out at wireless communication system channel resource allocation according to claim 4 is characterized in that, when the QoS of user terminal rate request is not satisfied as yet, i.e. and Rb _i＞Rf _iThe time, weight coefficient W _iSetting is greater than 1, to improve the dispatching priority of this user terminal.

6. the method that is used for carrying out at wireless communication system channel resource allocation according to claim 4 is characterized in that, when the QoS of user terminal rate request has been satisfied, i.e. and Rb _i＜Rf _iThe time, weight coefficient W _iSetting that is to say the terminal i for the active user less than 1, and its dispatching priority will be lower than other priority that do not satisfy user terminal.

7. the method that is used for carrying out channel resource allocation according to claim 4 at wireless communication system, it is characterized in that, the value of M should make the speed after dispatching satisfy the request rate of user terminal, make that again the proportional gain of dynamic dispatching is big as much as possible, satisfy at scheduling rates under the prerequisite of user terminal speed, M gets the maximum in all possible M value.

8. according to each described method that is used for carrying out channel resource allocation of claim 1 to 4, it is characterized in that this wireless communication system is one of code division multiple access or ofdm system at wireless communication system.

9. equipment that is used for carrying out channel resource allocation at wireless communication system, described wireless communication system comprises access point and a plurality of user terminal, described equipment comprises:

Calculation element, each that is used for from described a plurality of user terminals receives request message, described request message comprises each service transmission rate of being asked of described a plurality of user terminals and the transmission rate of having distributed to each user terminal on each subchannel, to calculate the ratio of described each user terminal between service transmission rate of being asked on each subchannel and the transmission rate of having distributed to each user terminal;

Determine device, be used for, determine to have the pairing user terminal of maximum ratio according to described ratio; And

Scheduler is used between next transmission period, calls the described user terminal with described maximum ratio.

10. the equipment that is used for carrying out at wireless communication system channel resource allocation according to claim 9 is characterized in that, also comprises:

Weighting device is used for producing the particular weights coefficient according to the service transmission rate of user terminal requests with the transmission rate of distributing to described user terminal, so that described ratio is weighted;

11. the equipment that is used for carrying out at wireless communication system channel resource allocation according to claim 10 is characterized in that, described definite device selects described ratio to be weighted a maximum numerical value of back, and determines the pairing user terminal of this greatest measure.

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