CN103369699B - A kind of graded dispatching method based on relay cellular system - Google Patents

Abstract

The invention provides a kind of graded dispatching method based on relay cellular system, conventional proportional fair algorithm is utilized to take into account the feature of throughput and fairness, feature for relay cellular system is improved algorithm, propose the RE-PF algorithm being applicable to graded dispatching, the method is mainly divided into original allocation and the two-stage dynamic scheduling of resource two steps of resource, wherein, need distinguish a jumping user and double bounce user according to the downlink path loss value of user at initial dispensing phase, be a jumping user and relay station, relay station be double bounce user original allocation resource by base station.Afterwards, system information is upgraded again with the time window set, according to RE-PF scheduling rule, complete schedule level one by base station, relay station completes second-level dispatching, by improving, equitable proportion thought is applied in relay system by the present invention, thus under the prerequisite not increasing signaling consumption on a large scale, the throughput of elevator system, realizes the Appropriate application of resource.

Description

A kind of graded dispatching method based on relay cellular system

Technical field

The present invention relates to wireless communication field, particularly a kind of graded dispatching method of the relay cellular system provided for advanced Long Term Evolution (LTE-Advanced) communication system.

Background technology

Along with the development of wireless communication technology and the continuous evolution of network, increasing new business emerges.Particularly with the broadband multimedia services that video calling, Online Video are representative, new requirement is proposed to the covering performance of cellular network.And in the environment such as dense city, city blind spot, indoor environment, high-speed railway, rural environments, the covering performance of network is often restricted.How under these specific scenes, to strengthen the network coverage, to meet the requirement of new business, become a problem demanding prompt solution.Although increase base station deployment, reduce the covering performance that base station spacing can promote network, this will increase complexity and the deployed with devices cost of network greatly.In order to promote the covering performance at networking, third generation partner program (3GPP), in standard Release8, clearly proposes relaying technique (Relay).Utilize this technology, relay station (RelayNode, hereinafter referred to as RN) can be disposed in macrocellular (Macro-cell), form relaying honeycomb (Relay-cell) in macrocellular inside.When base station or user distally transmit, signal is first received by relay station and carries out enhancing process, is transmitted to destination user or base station more afterwards.Compared with increasing the scheme of base station deployment, the deployment of relay station is more simple, and with low cost.Therefore, it is a kind of lifting capacity of communication system that relaying strengthens, and improves the effective way of network covering property.

In LTE-Advanced system, relaying has multiple mode classification.Here, whether there is community ID according to relaying cell, relaying can be divided into two classes, be respectively TypeI relaying and TypeII relaying.The feature of these two kinds of relayings is as follows.

(1) TypeI relaying

TypeI relaying is a kind of nontransparent trunking scheme, and each Relay-cell has independently community ID, and RN independently sends synchronizing signal, reference signal etc., possesses independently scheduling of resource ability.In TypeI relaying, eNodeB(base station) and RN between link be called as back haul link (BackhaulLink, hereinafter referred to as BL), the link between RN and user (UE) is called as access link (AccessLink, hereinafter referred to as AL).

In general, TypeI relaying adopts the mode of relaying (In-bandRelay) in band, and namely BL and AL uses identical frequency band by time division way, realizes the half-duplex transmitting-receiving of RN.In addition, 3GPP also defines TypeIa and TypeIb two kinds of trunking schemes at the predevelopment phase of LTE-Advanced system, and they have the feature of TypeI relaying.But TypeIa relaying adopts the mode of the outer relaying of band (Out-bandRelay), namely BL and AL uses different frequency bands, without the need to time division transmission; Although TypeIb relaying is also relaying in band, the isolation of the radio frequency unit of BL and AL is better, can realize the full duplex transmitting-receiving of RN.

(2) TypeII relaying

TypeII relaying is a kind of transparent relay mode, and independently community ID, RN do not have independently broadcast channel, synchronizing channel, pilot tone and control channel, nothing independently scheduling of resource ability to each Relay-cell.

Because TypeI relaying can realize expanding the coverage area, the target of capacity, also possesses good backwards compatibility simultaneously, and thus this mode becomes the relay form that 3GPP mainly studies.

In a wireless communication system, normal adoption rate justice (ProportionalFair, hereinafter referred to as PF) dispatching algorithm completes wireless resource scheduling.PF algorithm has taken into full account the fairness between the Real-time Channel gain of each user and user's average transmission rate, for throughput of system and user fairness provide good compromise.The scheduling rule of PF algorithm can characterize by (1) formula.

$\widehat{k\left(t\right)}=\arg \underset{k\∈U}{\max }\left\{\frac{{\left[r_k\left(t\right)\right]}^{\mathrm{\α}}}{{\left[R_k\left(t\right)\right]}^{\mathrm{\β}}}\right\}---\left(1\right)$

Wherein, r _kt () is the real-time Data Transmission speed of t user k, the transmission user that t is selected, R _kt () is the average transmission bit rate to t user k, U is that user gathers, α and β is system call fairness modifying factor, and usual value is 1.

After each scheduling process terminates, system needs according to the average transmission bit rate in (2) formula section T update time.

$R_k(t+1)=(1-\frac{1}{T})R_k\left(t\right)+\frac{r_k\left(t\right)}{T}---\left(2\right)$

(2), in formula, T is a time window, and T is larger, and the throughput of system is larger; T is less, and the fairness of user scheduling is better.By this formula, scheduler can carry out dynamic dispatching to intrasystem Radio Resource, realizes the reasonable distribution of resource.

Traditional PF algorithm make use of the time-varying characteristics of subscriber channel fully, has taken into account throughput of system and user fairness, distributes limited frequency resource comparatively efficiently, thus becomes in wireless communication system and uses wider dynamic resource scheduling algorithm.But after introduce RN in LTE-Advanced system, the structure of relaying honeycomb there occurs no small change compared with legacy cellular, if directly apply in relay cellular system by traditional PF algorithm, will have following deficiency.

(1) in traditional cellular system, PF algorithm needs the time-varying characteristics utilizing channel, and system resource allocation situation and customer service request situation are fed back to base station end in real time.But, after introducing RN, whole macrocellular will be divided into central area and fringe region, central user (one jump user) can directly by information feed back to eNodeB, and edge customer (double bounce user) need could by information feed back to eNodeB by RN, this will bring extra signaling consumption for system, and increases time delay, and existing PF algorithm can not adapt to the demand of relay cellular network transmission means.

(2) traditional PF algorithm just broadly considers the transmission rate of single user, does not consider the priority orders of all kinds of business, thus cannot meet the demand of current cellular networks " multi-user " " multi-service " in scheduling rule.

Thus, traditional PF algorithm can not directly apply in relay cellular system, must improve according to the network design mode of reality.

Summary of the invention

The object of the present invention is to provide a kind of graded dispatching method based on relay cellular system.

For achieving the above object, present invention employs following technical scheme.

1) at Intra-cell, user area is divided into a jumping user and double bounce user according to downlink path propagation loss value by base station, completed the resource original allocation process of jumping user and relay station to by base station, complete the resource original allocation process to double bounce user by relay station;

2) after step 1), take time window as the cycle, by one jump user to described base station, double bounce user requires to described relay station feedback velocity, the priority of average transmission bit rate and new arrival business, meanwhile, system update one jumps the average transmission bit rate of user and double bounce user;

3) through step 2) after, calculate dispatching priority by described base station and relay station according to the proportional fair scheduling under relaying enhanced scene, then base station and relay station complete the two-stage dynamic scheduling of resource process.

Described resource original allocation process is a static assigning process, all users of new arrival community first send resource request to base station, simultaneously, in system initialisation phase, relay station also sends resource request to base station, base station jumps user or relay station Resources allocation according to the resource request that jumps user or relay station to one, after relay station obtains resource, then by relay station according to the resource request of double bounce user to double bounce user resource allocation.

When after the resource request that base station receives from relay station and user, relay station and user area branch away according to the source of request by base station, if resource request is from user, then base station sends reference signal to user, and then base station calculates downlink path propagation loss value L according to following formula:

L=58.83+37.6lgD+21lgf

Wherein, D represents the distance of base station and user, and f represents the carrier frequency (generally getting 2GHz) of relay cellular system, and base station is by the downlink path propagation loss value of each user and descending path loss decision threshold L _thcompare, L _thfetch bit in the downlink path propagation loss value of the user of relay station position, if L≤L _th, then user is a jumping user; If L>L _th, then user is double bounce user.

Described the two-stage dynamic scheduling of resource process comprises schedule level one and second-level dispatching, in schedule level one, is completed the scheduling of resource process of relay station and being jumped to user by base station; In second-level dispatching, complete the scheduling of resource process to double bounce user by relay station.

Described one dispatching priority of jumping user or double bounce user calculates according to the following formula:

$W_k=\mathrm{\αPR}{I}_k\×\mathrm{\β}\frac{\underset{i\∈U}{\mathrm{\Σ}}{R}_i\left(t\right)}{R_k\left(t\right)}\×\mathrm{\γ}\frac{R_k(t+1)}{\underset{i\∈U}{\mathrm{\Σ}}{R}_i(t+1)}$

Wherein, W _kthe dispatching priority of user, PRI _kfor user newly arrives the priority of business, R _kt () is the average transmission bit rate to t user k, R _it () is the average transmission bit rate of each user i of t, R _i(t+1) be average transmission bit rate to t+1 moment user i, U is that user gathers, and α, β and γ are regulation coefficient, generally, gets α=β=γ=1.

The dispatching priority of described relay station calculates according to the following formula:

$W_{\mathrm{RN}\_i}=\frac{\underset{i=1}{\overset{N}{\mathrm{\Σ}}}{R}_{\mathrm{RN}\_i}\left(t\right)}{R_{\mathrm{RN}\_i}\left(t\right)}\×\frac{R_{\mathrm{RN}\_i}(t+1)}{\underset{i=1}{\overset{N}{\mathrm{\Σ}}}{R}_{\mathrm{RN}\_i}(t+1)}$

Wherein, W _{rN_i}for the dispatching priority of relay station, N is the number of the relay station disposed in community, R _{rN_i}(t) for relay station i is to the average transmission bit rate of t, R _{rN_i}(t+1) be the average transmission bit rate in relay station i to t+1 moment, R _{rN_i}(t) and R _{rN_i}(t+1) all characterize by the average transmission bit rate sum of all double bounce users in relay station i administrative relaying honeycomb.

The present invention is according to the feature of relay cellular system, propose the concept of " the two-stage dynamic scheduling ", after completing the original allocation process of resource, the reasonable distribution of resource is realized by two-level scheduler, wherein, first order scheduling is completed by the scheduler of base station, and second level scheduling is completed by the scheduler of RN.After being divided into two-stage to complete scheduling of resource, a jumping user and double bounce user will be distinguished, and base station only need complete the scheduling of resource task of relay station and being jumped to user, and will have been come by relay station the scheduling of resource of double bounce user.Like this, the system resource distribution information in real time got and customer service solicited message can be fed back to the relay station of administration its place Relay-cell by double bounce user, for calculating dispatching priority, and without the need to information being reported again base station, like this, just decrease the signaling consumption of system, reduce scheduling delay simultaneously.

Dispatching method of the present invention improves existing proportional fair algorithm, the rate requirement, average transmission rate and the new business that are obtained respectively in region within the jurisdiction by base station and relay station arrive situation, and the priority of schedule level one and second-level dispatching is obtained by these data, this mode using the priority of business as a factor of influence, bring in the calculating of dispatching priority, this is the useful supplement to conventional P F algorithm, makes proportional fair algorithm more adapt to the multiple services demand of LTE-Advanced cellular network process.

Compared with traditional PF algorithm, the present invention also will bring following beneficial effect: the first, promote the average throughput of user; The second, the elevator system availability of frequency spectrum.

Accompanying drawing explanation

Fig. 1 is the schematic diagram of relay cellular system;

Fig. 2 is the graded dispatching method general flow chart that the present invention is based on relay cellular system;

Fig. 3 is resource original allocation flow chart of the present invention;

Fig. 4 is the algorithm flow chart of the two-stage dynamic scheduling of resource of the present invention;

Fig. 5 is that algorithm of the present invention compares with user's average throughput of conventional P F dispatching algorithm;

Fig. 6 is that algorithm of the present invention compares with the system spectrum utilance of conventional P F dispatching algorithm.

Embodiment

Below in conjunction with accompanying drawing, the invention will be further described.

For the feature of LTE-Advanced relay cellular system, the present invention makes improvement for traditional PF algorithm, proposes the PF dispatching algorithm (RelayEnhancedPF, hereinafter referred to as RE-PF) under relaying enhanced scene.RE-PF algorithm, on the basis of the design philosophy of inheriting tradition PF algorithm, is made improvement to the system call process after introducing RN, is made RN bear a part of scheduling feature, reduce the scheduling overhead of eNodeB., scheduling rule is revised, to adapt to the demand of service with different priority levels meanwhile.

The process of whole Resourse Distribute is divided into static resource initial dispensing phase and dynamically second-level dispatching stage.Resource initial dispensing phase, be in fact after having run long period of time to whole system restarting process, distribute to RN and UE resource requirement statically; In the second-level dispatching stage, after introducing RE-PF algorithm, reasonably dispatch arriving situation, average transmission bit rate and the resource of new rate requirement to network according to the new business of user.

All users in whole macrocellular are divided into a jumping user and double bounce user according to propagated loss value, are responsible for original allocation and the scheduler task of resource respectively by base station dispatcher and relay station scheduler.Compared with traditional base station centralized scheduling, in the present invention, relay station assume responsibility for a part of scheduling of resource task, like this, the system resource distribution information in real time got and customer service solicited message can be fed back to the RN of administration its place Relay-cell by double bounce user, for RE-PF algorithm, and without the need to information being reported again eNodeB, like this, just decrease the signaling consumption of system, reduce scheduling delay simultaneously.

Bring in the process of resource original allocation and resource dynamic scheduling using service priority as factor of influence, arrive business for object with user and propose resource request, system is traffic assignments resource according to the transmitted bit rate requirement of business.Like this, multiple services demand can be met well.

Being the process that a jumping user and RN complete schedule level one by eNodeB, is the process that double bounce user completes second-level dispatching by RN.These two processes are the processes connected each other again independently of one another." independently of one another " says that two steps will calculate respective dispatching priority respectively; " connect each other " is say that in second-level dispatching, the resource of RN needs to be distributed by eNodeB by schedule level one, and eNodeB carries out scheduling of resource to each RN and needs RN to feed back the rate information of the double bounce user in second-level dispatching in schedule level one, the two complements each other, and together constitutes a kind of dispatching method in relay cellular system.

The present invention inherits the feature of conventional proportional equity dispatching mode, the thought of proportion of utilization justice, in conjunction with the feature of relay cellular system, propose the Proportional Fair scheme of improvement---the PF dispatching algorithm under relaying enhanced scene, i.e. RE-PF algorithm, the scheduling rule of this algorithm is shown below:

$W_k=\mathrm{\αPR}{I}_k\×\mathrm{\β}\frac{\underset{i\∈U}{\mathrm{\Σ}}{R}_i\left(t\right)}{R_k\left(t\right)}\×\mathrm{\γ}\frac{R_k(t+1)}{\underset{i\∈U}{\mathrm{\Σ}}{R}_i(t+1)}$

Wherein, W _kthe dispatching priority of user, PRI _kfor user newly arrives the priority of business, R _kt () is the average transmission bit rate to t user k, R _i(t+1) be average transmission bit rate to t+1 moment user i, U is that user gathers, and α, β, γ are regulation coefficient (needing to arrange according to the concrete situation of network).This scheduling rule considers the current rate conditions of the priority of arrival business, user and user rate situation simultaneously.System will be first dispatching priority W _kthe user that value is large provides resource, and when other two constant, high PRI _kvalue, low R _k(t) value, high R _i(t+1) value is all said and is made W _kvalue increases, thus promotes the dispatching priority of user.

RN and UE all in community is counted as " user " (comprise RN, and jump user and double bounce user) of eNodeB, and a scheduling process mainly point two-stage has been come.

(1) schedule level one.In schedule level one, completed the scheduling of resource process of RN and being jumped to user by the scheduler of eNodeB.After eNodeB obtains rate requirement, average transmission rate and the new business arrival situation that this part " user " feed back, respectively user is jumped to RN and according to the scheduling rule of RE-PF and carry out scheduling of resource, realize the reasonable distribution of resource in Macro-cell.Wherein, the total rate requirement in the Relay-cell of the rate requirement of RN and average transmission rate also its administration i.e. and average transmission rate, draw after needing to add up double bounce user.

(2) second-level dispatching.In second-level dispatching, complete the scheduling of resource process to double bounce user by the scheduler of RN.After each RN obtains the rate requirement of double bounce user feedback, average transmission rate and the new business arrival situation in the Relay-cell of oneself administration, according to RE-PF scheduling rule, scheduling of resource is carried out to double bounce user, realize the reasonable distribution of resource in Relay-cell.

This two-level scheduler is all dynamic processes, needs eNodeB or RN to collect the rate information of inside, jurisdiction district in time, is realized the reasonable distribution of resource by scheduling rule.The dynamic of scheduling process is also ensured by RE-PF algorithm just.

Graded dispatching method based on relay cellular system proposed by the invention, comprises the following steps:

(1) all regarded as by RN and UE in whole cellular cell " user " of eNodeB, send resource request by " user " to eNodeB, eNodeB distinguishes RN and UE according to request source;

(2) eNodeB distinguishes a jumping user and double bounce user according to downlink path propagation loss value, and completes the resource original allocation process of jumping user and RN to; Subsequently, RN completes the resource original allocation process to double bounce user;

(3) after completing original allocation process, according to the time window set, jump user by one and arrive situation to eNodeB, double bounce user to the requirement of RN feedback velocity, Mean Speed and new business;

(4) system upgrades average transmission bit rate according to time window;

(5) the two-stage dynamic scheduling process is completed by eNodeB and RN respectively according to RE-PF scheduling rule.

In those steps, the original allocation process that (1) and (2) is resource, this process is a static assigning process; (3), (4), (5) are second-level dispatching process, and this process is a dynamically scheduling process.

Embodiment

The present invention is applicable to the relay cellular system in 4GLTE-Advanced communication network, is intended to the feature of proportional fair algorithm according to relay cellular system to improve, and is applied in this system.By the two-stage dynamic scheduling of resource, under the prerequisite not increasing signaling consumption, realize the Appropriate application to limited frequency resource, with capacity.A kind of graded dispatching method based on relay cellular system that the present invention proposes forms primarily of two parts, i.e. resource initial dispensing phase and resource the two-stage dynamic scheduling phase.

See Fig. 1, system that employs the mode of summit excitation, on the perpendicular bisector on little offset eNodeB two limits far away, apart from center (R is the radius of macrocellular) place sets up 2 RN(also can set up 4 or more RN according to actual needs).Wherein, the region that eNodeB directly administers is the region of Macro-cell, RN administration is the edge that Relay-cell, RN are deployed in Macro-cell.When distinguishing a jumping user and double bounce user, required path loss decision threshold L _thbe taken as the descending circuit loss value at RN place.In general, one jumps user is positioned at Macro-cell, and double bounce user is positioned at the region that Relay-cell does not overlap with Macro-cell, and specifically available (3) formula shows by aggregate manner.

$\left\{\begin{array}{c}\mathrm{One}\_\mathrm{hop}\_\mathrm{UE}\∈\mathrm{Macro}-\mathrm{cell}\\ \mathrm{Two}\_\mathrm{hops}\_\mathrm{UE}\∈\mathrm{Relay}-\mathrm{cell}\backslash (\mathrm{Relay}-\mathrm{cell}\∩\mathrm{Macro}-\mathrm{cell})\end{array}\right.---\left(3\right)$

See Fig. 2, what step [201] was corresponding is resource original allocation process, comprises the differentiation process of RN and UE, the differentiation process of a jumping user and double bounce user and resource original allocation process; What step [202] was corresponding is the two-stage dynamic scheduling of resource process, and window is to eNodeB or RN feedback resource allocation information process in required time to comprise user, eNodeB and RN completes the two-stage dynamic scheduling process according to RE-PF scheduling rule.

See Fig. 3, the step [201] in this process corresponding diagram 2, and [201] are divided into five sub-steps, namely step [301] is to [305].Deep elaboration will be done to [305] below to [301].

Step [301]: in Fig. 1 scene, no matter the new all UE arriving community, be in Macro-cell or Relay-cell, all the eNodeB first to macrocellular sent resource request.Meanwhile, in system initialisation phase, RN also will send resource request and can manage to obtain it part resource to eNodeB.When after the resource request that eNodeB receives from RN and UE, by according to the source of request, RN and UE is distinguished.In this step, eNodeB regards RN and UE of all transmission resource request as oneself " user ".When determining " user " for RN, go to step [302]; When determining " user " for UE, go to step [303];

Step [302]: if resource request is from RN, then eNodeB distributes the resource of 10%-15% to each RN, for RN administration scheduling;

Step [303]: if resource request is from UE, then eNodeB sends reference signal to UE, calculates descending circuit loss value L according to propagated loss formula (4).

L(dB)=58.83+37.6lgD(km)+21lgf(MHz)（4）

After eNodeB obtains the descending circuit loss value of each UE, need and the descending path loss decision threshold L set _thcompare, L _thget reference signal that eNodeB sends to radius of society Shang Ju center the descending circuit loss value of place user, as shown in (5) formula.

$L_{\mathrm{th}}\left(\mathrm{dB}\right)=58.83+37.61g\left(\frac{2}{3}R\right)\left(\mathrm{km}\right)+211\mathrm{gf}\left(\mathrm{MHz}\right)---\left(5\right)$

By L and L _thafter comparing, if L≤L _th, then UE is a jumping user; If L>L _th, then UE is double bounce user;

Step [304]: if UE is a jumping user, then press demand to its original allocation resource by eNodeB; If UE is double bounce user, then the RN to place Relay-cell sends resource request, then by RN as required to its original allocation resource.The resource requirement of user is determined by the concrete grade of service, and the business in LTE-Advanced system is divided into four large classes by 3GPP, as shown in table 1.For simplicity, when this part describes algorithm, give tacit consent to a user and can only accept a business simultaneously;

The LTE-Advanced system business priority of table 13GPP definition

Step [305]: eNodeB checks whether that all resource request are obtained for process, if not, then goes to step [301]; If so, then ending resource original allocation process.

See Fig. 4, the step [202] in this process corresponding diagram 2, and [202] are divided into three sub-steps, namely step [306] is to step [308].Deep elaboration will be done to [308] below to [306].

Step [306]: complete the process of resource original allocation at relay cellular system after, community provides service for user.Now, Preset Time window T is needed _r(being generally taken as 1ms), system with this time window for the cycle, will carry out the two-stage dynamic scheduling of resource process.At the end of time window, namely jump by one that user feeds back current user rate requirements to eNodeB, double bounce user to RN, the new business of average transmission rate and user arrives situation.ENodeB or RN obtains current network state, customer service arrives and rate requirement, for reasonably scheduling resource is prepared.

Step [307]: when each time window terminates, system upgrades the average transmission bit rate of user k in this time window according to the update rule shown in (6) formula.

$R_k(t+1)=(1-\frac{1}{T_r})R_k\left(t\right)+\frac{r_k\left(t\right)}{T_r}---\left(6\right)$

Wherein, R _kt () is the average transmission bit rate to t user k, R _k(t+1) be average transmission bit rate to t+1 moment user k, r _kt () is the real-time Data Transmission speed of t user k, T _rfor the value of time window.

Step [308]: after average transmission bit rate upgrades, eNodeB calculates according to RE-PF scheduling rule the schedule level one priority that one jumps user, and meanwhile, RN also calculates the second-level dispatching priority of double bounce user according to this rule.RE-PF scheduling rule is as shown in (7) formula.

$W_k=\mathrm{\αPR}{I}_k\×\mathrm{\β}\frac{\underset{i\∈U}{\mathrm{\Σ}}{R}_i\left(t\right)}{R_k\left(t\right)}\×\mathrm{\γ}\frac{R_k(t+1)}{\underset{i\∈U}{\mathrm{\Σ}}{R}_i(t+1)}---\left(7\right)$

Wherein, W _kthe dispatching priority of user, PRI _kfor user newly arrives the priority of business, R _kt () is the average transmission bit rate to t user k, R _i(t+1) be average transmission bit rate to t+1 moment user i, U is that user gathers, and α, β, γ are regulation coefficient, generally, gets α=β=γ=1.In formula, the rate conditions that three on the right of equal sign priority characterizing arrival business respectively, user are current and user rate situation.System will be first dispatching priority W _kbe worth large user scheduling resource, and when other two constant, high PRI _kvalue, low R _k(t) value, high R _i(t+1) value is all said and is made W _kvalue increases, thus promotes the dispatching priority of user.

Especially, the scheduling rule that eNodeB need provide by (8) formula for the schedule level one of RN performs.

$W_{\mathrm{RN}\_i}=\frac{\underset{i=1}{\overset{2}{\mathrm{\Σ}}}{R}_{\mathrm{RN}\_i}\left(t\right)}{R_{\mathrm{RN}\_i}\left(t\right)}\×\frac{R_{\mathrm{RN}\_i}(t+1)}{\underset{i=1}{\overset{2}{\mathrm{\Σ}}}{R}_{\mathrm{RN}\_i}(t+1)}---\left(8\right)$

Wherein, R _{rN_i}t () is RN _ito the average transmission bit rate of t, R _{rN_i}(t+1) be RN _ito the average transmission bit rate in t+1 moment, both all uses RN _iin administrative Relay-cell, the average transmission bit rate sum of all double bounce users characterizes.

So far, the two-stage dynamic scheduling of resource process just completes, and system can carry out according to the change of network state the dynamic dispatching that continues in ensuing time window.Because RE-PF dispatching algorithm inherits the characteristic of proportional fair algorithm, the compromise of throughput of system and scheduling fairness in LTE-Advanced relay cellular system thus can be realized.And algorithm improves for relay scene, the system that can ensure is under the prerequisite not increasing signaling consumption, and elevator system throughput, more reasonably utilizes frequency resource.

The present invention will bring following beneficial effect:

First, see Fig. 5, RE-PF algorithm makes user's average throughput obtain obvious lifting compared with conventional P F algorithm, this is because RE-PF algorithm can be the new arrival traffic scheduling resource of each user according to the priority of different business, thus be each traffic scheduling resource according to the urgent degree of resource requirement, achieve the Appropriate application of resource;

Secondly, see Fig. 6, because the RE-PF algorithm in the two-stage dynamic scheduling of resource is incorporated in dispatching priority computational process by newly arriving service priority, thus can be more reasonably user scheduling resource according to business demand, unit frequency resource is made to transmit more data, the elevator system availability of frequency spectrum.

In a word, the present invention is based on the feature of relaying cellular communication system, introduce the concept of " the two-stage dynamic scheduling ", propose RE-PF algorithm, by the scheduling of resource task of the whole community of eNodeB and RN shared.The present invention suggests plans and is mainly divided into following step:

[301] " user " sends resource request to eNodeB, and it is RN or UE that eNodeB distinguishes " user " according to message source.If " user " is RN, then go to step [302]; If " user " is UE, then go to step [303];

[302] eNodeB is to each RN original allocation resource;

[303] be calculated to the descending circuit loss value of UE by eNodeB, distinguish one by circuit loss value and jump user and double bounce user;

[304] if one jumps user, be then a jumping user original allocation resource by eNodeB according to service priority; If double bounce user, user determines the Relay-cell at oneself place, to RN request resource, after RN receives resource request, is double bounce user original allocation resource according to service priority;

[305] check whether that all resource request are obtained for process, if not, then go to step [301]; If so, then go to step [306];

[306] cellular cell provides service for user.The time window that presets of Tr(at set intervals), user requires to eNodeB or RN feedback velocity, average transmission rate and new business arrive situation;

[307] system is according to the average transmission bit rate in update rule window update time Tr;

[308] eNodeB is according to the scheduling rule first order calculation dispatching priority of RE-PF, completes schedule level one process; Meanwhile, RN also calculates second-level dispatching priority according to the scheduling rule of RE-PF, completes second-level dispatching process.After this has been dispatched, system continues to upgrade the information such as average transmission rate with time window Tr, enters dispatching cycle next time.

Wherein, step [301] to step [305] is resource original allocation process, and step [306] to step [308] is the two-stage dynamic scheduling process.

Claims (4)

1., based on a graded dispatching method for relay cellular system, it is characterized in that: comprise the following steps:

1) at Intra-cell, user area is divided into a jumping user and double bounce user according to downlink path propagation loss value by base station, completed the resource original allocation process of jumping user and relay station to by base station, complete the resource original allocation process to double bounce user by relay station;

2) through step 1) after, take time window as the cycle, by one jump user to described base station, double bounce user requires to described relay station feedback velocity, the priority of average transmission bit rate and new arrival business, meanwhile, system update one jumps the average transmission bit rate of user and double bounce user;

3) through step 2) after, calculate dispatching priority by described base station and relay station according to the proportional fair scheduling under relaying enhanced scene, then base station and relay station complete the two-stage dynamic scheduling of resource process;

Described one dispatching priority of jumping user or double bounce user calculates according to the following formula:

Wherein, W _kthe dispatching priority of user, PRI _kfor user newly arrives the priority of business, R _kt () is the average transmission bit rate to t user k, R _it () is the average transmission bit rate of t user i, R _i(t+1) be average transmission bit rate to t+1 moment user i, U is that user gathers, and α, β and γ are regulation coefficient;

The dispatching priority of described relay station calculates according to the following formula:

Wherein, W _{rN_i}for the dispatching priority of relay station, N is the number of the relay station disposed in community, R _{rN_i}(t) for relay station i is to the average transmission bit rate of t, R _{rN_i}(t+1) be the average transmission bit rate in relay station i to t+1 moment, R _{rN_i}(t) and R _{rN_i}(t+1) all characterize by the average transmission bit rate sum of all double bounce users in relay station i administrative relaying honeycomb.

2. a kind of graded dispatching method based on relay cellular system according to claim 1, it is characterized in that: described resource original allocation process is a static assigning process, all users of new arrival community first send resource request to base station, simultaneously, in system initialisation phase, relay station also sends resource request to base station, base station jumps user or relay station Resources allocation according to the resource request that jumps user or relay station to one, relay station obtains after resource, then by relay station according to the resource request of double bounce user to double bounce user resource allocation.

3. a kind of graded dispatching method based on relay cellular system according to claim 2, it is characterized in that: when after the resource request that base station receives from relay station and user, relay station and user area branch away according to the source of request by base station, if resource request is from user, then base station sends reference signal to user, and then base station calculates downlink path propagation loss value L according to following formula:

L＝58.83+37.6lgD+21lgf

Wherein, D represents the distance of base station and user, and f represents the carrier frequency of relay cellular system, and base station is by the downlink path propagation loss value of each user and descending path loss decision threshold L _thcompare, L _thfetch bit in the downlink path propagation loss value of the user of relay station position, if L≤L _th, then user is a jumping user; If L>L _th, then user is double bounce user.

4. a kind of graded dispatching method based on relay cellular system according to claim 1, it is characterized in that: described the two-stage dynamic scheduling of resource process comprises schedule level one and second-level dispatching, in schedule level one, completed the scheduling of resource process of relay station and being jumped to user by base station; In second-level dispatching, complete the scheduling of resource process to double bounce user by relay station.