CN101431811A - Cross-layer structure for guaranteeing QoS in WiMAX and QoS combination control method - Google Patents

Abstract

The invention discloses a layer-crossing structure for assuring the QoS in the WiMAX and a compound control method of the QoS. The layer-crossing design is used to divide the basic data control plane into two planes of QoS resource management and data service delivery. The QoS resource managing plane delivers the multiple media communication service flow by applying the layer to the MAC layer; controlling the PHY layer be gathered by the AMC channel mode selection information to the MAC layer transmission, security system to achieve cross-layer QoS control of the joint management of data services and access to the QoS flow control performance indicators set by the user in the system the threshold value; data streaming services to submit sub-plane containing a variety of norms to follow IEEE 802.16 data services stream processing module, the management of their resources in accordance with sub-QoS management plane carries control signaling information data services for all types of flow classification and scheduling to achieve layer by layer submitted. The present invention system in maintaining a high throughput at the same time being able to service a number of QoS flow limit indicators within the target threshold, taking into account a fair rate of customers.

Description

The cross-layer structure of guaranteed qos and QoS combination control method thereof among the WiMAX

Technical field

The invention belongs to communication technical field, relate to the wireless network cross-layer structure and the QoS combination control method thereof that a little arrive multiple spot PMP whole world inserting of microwave interoperability WiMAX network.

Background technology

WiMAX based on IEEE 802.16 standards is a kind of emerging wireless access wide band technology that is applicable to wireless MAN WMAN, be expected to replace cable modem or Digital Subscriber Line mode, in nlos environment, insert for numerous users provide the WiMAX of " last mile ".Fig. 1 has provided typical PMP WiMAX network topology structure, the service that each subscriber station SS expectation base station BS provides not only is confined to simple data communication, also comprise various multimedia communications, for example, video conference, Streaming Media download etc., how limited at capacity, become when bit error rate is very high in the wireless environment to numerous users provide high speed high-quality multimedia communication service, become one of technical problem that the WiMAX development needs to be resolved hurrily.

Service quality QoS has embodied the consumer provides the satisfaction of service to the server, is a kind of overall merit to server's service level.For communication network, a series of service requests that should satisfy when QoS is the Network Transmission Business Stream, performance parameters such as concrete available bandwidth, time delay, delay variation, Loss Rate, throughput characterize.At present, the various methods for designing of guaranteed qos are based upon on this layer architecture of the Open System Interconnection OSI Reference Model basis usually in the wireless network, typical 5 layers of layer architecture comprise physical layer, data link layer, network layer, transport layer and application layer from the bottom to top successively, and this wireless network layer architecture faces following two challenges greatly:

1. for the high level that comprises network layer, transport layer and application layer, can support the service flow that the QoS type is different, and be responsible for being provided with end-to-end link, if adopt the wireless network hierarchical design, the low layer that comprises physical layer and data link layer is difficult to the QoS demand of acquisition from high level, for example, time delay and throughput are so can't in time adjust the resource distribution strategy.

2. for low layer, can detect the dynamic characteristic of wireless channel, wireless channel has that capacity is limited, bit error rate is higher, channel quality in time with characteristics such as frequency change, when particularly wireless channel experiences the deep fading, connect the very big bandwidth of distribution even system is a certain service, its performance still may not reach the qos requirement of predesignating, if adopt traditional wireless network hierarchical design, high-rise being difficult to obtains these characteristics, so can't in time adjust the call admission control strategy.

To sum up can get, the mutability of communication environment and the diversity of communication service have determined WiMAX to stride the necessity of layer design.Stride layer design philosophy and clearly proposed by Zygmunt J.Haas the earliest, in wireless network 5 layer protocol architectural models, information sharing is not limited in the adjacent layering, also is present in non-conterminous minute interlayer.As shown in Figure 2, desirable cross-layer method is that the information transmission is divided into upwards information sharing and downward information sharing two parts, each layer running coordinated in signaling transmission by necessity, thereby reach the purpose of improving overall performance, this thought is that WiMAX network configuration design of new generation has indicated direction.

As the current approach that leads to WiMAX, IEEE 802.16 standards have only defined the air interface data control plane between BS and the SS, are made up of physical layer and media access control MAC layer, as shown in Figure 3.WiMAX supports four kinds of physical layer transmission technology, be respectively that single carrier SC, single carrier insert SCa, orthogonal frequency division multiplex OFDM and OFDM access OFDMA, four kinds of technology all can adopt these three kinds of transmission mechanisms of TDD, FDD and Half-Frequency Division Duplex Half-FDD.In recent years, the OFDMA based on tdd mode becomes the broadband wireless transmission technology that people pay close attention to.OFDM can make data send across whole frequency band, OFDMA as its evolution technology then can be loaded into the service flow of transmitting on the parton carrier wave on channel subcarrier basis, each system user is with selective channel condition subchannel transmission service flow preferably, guarantee that each subcarrier is all used by the more excellent user of respective channels condition, thereby obtain the multi-user diversity gain on the frequency.

In IEEE 802.16 standards, the MAC layer is made of three sublayers, is respectively:

1. serve the specific CS of converging sublayer: provide external network data to arrive the mapping of MAC layer.By CS Service Access Point SAP external network data is mapped to MAC layer service data unit MSDU, and related with corresponding M AC service flow sign SFID and connection identifiers CID, finish the classification of MSDU.

2. public portion C PS sublayer: the Core Feature of MAC layer is provided, comprises system's access, allocated bandwidth, connection foundation and be connected maintenance.Receive MSDU by MAC SAP from the CS sublayer, and according to its category division to specific MAC connections, carry out transfer of data according to every kind of data delivery mechanism that connects support then.

3. Security Sublayer: cipher key change and encryption function that authentication, safety are provided.

IEEE 802.16 standards are introduced the MAC layer with the QoS support scheme, to be divided into 5 classes from the application layer multimedia communication service flow on upper strata, be respectively unsolicited grant service UGS, real-time polling service rtPS, Extended real-time Polling Service ertPS, non-real-time polling service nrtPS and Best-Effort service BE, adopt connection-oriented mode to provide various multimedia communication access services to numerous users.Yet, in wireless network, the QoS safeguard work of finishing multimedia service stream that protocol layer all can not isolate arbitrarily, every layer all has the agreement that relates to the QoS management, for example, the transmission control protocol TCP of transport layer and User Datagram Protoco (UDP) UDP, network layer be based on various standards on the integrated service IntServ of Mobile Internet Protocol IP and Differentiated Services DiffServ and the MAC layer, for example, and the QoS support scheme that IEEE 802.11 and IEEE 802.16 relate to.It should be noted that: the protocol layer difference, the QoS performance index of weighing the multimedia communication service flow are also different, for example, the performance index of physical layer are bit error rates, the performance index of MAC layer are throughput or the throughputs that SS obtains, network layer performance characterizes with time delay usually, and transport layer then is a packet error rate.Usually need use a plurality of performance index to weigh the quality of service flow simultaneously, for example, the throughput span of video conference be (32kb/s, 384kb/s), time delay is no more than 160ms, delay variation is no more than 50ms.

Summary of the invention

The objective of the invention is to the deficiency of avoiding above-mentioned wireless network hierarchy aspect the QoS guarantee, to exist, employing is striden layer design philosophy existing MAC layer QoS support scheme in IEEE 802.16 standards is expanded, the cross-layer structure and the QoS combination control method thereof of guaranteed qos among a kind of WiMAX are proposed, thus the time become in the wireless WiMAX network and provide high speed high-quality multimedia communication service to numerous users.

For achieving the above object, the cross-layer structure of guaranteed qos among the WiMAX that the present invention adopts, comprise: PHY layer, MAC layer and high level, these three layers constitute the WiMAX basic data control plane, and whole WiMAX basic data control plane vertically is divided into the sub-plane of QoS resource management and data, services stream is submitted sub-plane; Wherein, the different QoS administration module of multiple function is contained on the sub-plane of described QoS resource management, these modules are by various managing signaling coordinate operation, control is high-rise transmits the application layer QoS demand of all kinds of multimedia communication service flow to the MAC layer, to the transmission of MAC layer, the QoS performance index that data, services stream is obtained are limited in the system user preset threshold control PHY layer with the subchannel AMC model selection information collected; Described data, services stream is submitted sub-plane, contain the different data, services stream processing module of multiple function, these modules are followed the standard of IEEE 802.16 standard formulations, and according to the control information of managing signaling carrying in the sub-plane of QoS resource management the Various types of data service flow is classified, dispatch, realization is successively submitted.

For achieving the above object, the present invention has adopted the QoS combination control method based on cross-layer structure, comprises the steps:

1. the channel status detecting module that is positioned at the BS place is broadcast probe request signaling CQI-REQ periodically, the channel state feedback module that is positioned at each SS place receives after this signaling that loopback CQI-RSP in response immediately, and channel SNR surveyed, the channel state feedback module sends the CQI-ACK that carries this SNR information by the channel status detecting module of based on feedback link to the BS place;

2. the AMC mode selection module that is positioned at the BS place sends demand signalling AMC-REQ periodically to the channel status detecting module, behind the response signaling AMC-RSP that receives the loopback of channel status detecting module, according to the signal to noise ratio aggregate information { SNR of this signaling bear _{K, n}| k=1,2 ..., K ﹠amp; N=1,2 ..., N} and predefined AMC model selection strategy generate AMC model selection aggregate information { l _{K, n}| k=1,2 ..., K ﹠amp; N=1,2 ..., N};

3. the AMC mode selection module that is positioned at the BS place sends layer signaling AMC-MES that stride that carries AMC model selection aggregate information periodically to the sub channel resource configuration module, the AMC mode selection module generates user's subchannel pairing aggregate information { C according to AMC model selection aggregate information and predefined sub channel resource configuration module strategy _{K, n, l}| k=1,2 ..., K ﹠amp; N=1,2 ..., N}, the sub channel resource configuration module generates DL-MAP and UL-MAP according to user's subchannel pairing set ground information cycle, and the one-tenth frame module that data, services stream is submitted in the sub-plane encapsulates and framing downlink burst stream and uplink burst stream according to this two classes signaling;

4. after a certain SS in BS and the system sets up synchronously, the call admission administration module of call admission administration module to the BS place that is positioned at this SS place sends call admission request signaling DSA-REQ periodically, BS at first sends the DSA-RSP signaling as response after receiving this signaling, send resource query signaling RES-REQ to the sub channel resource configuration module then, when the sub channel resource configuration module finished for the 3rd step, again to the call admission administration module loopback resource acquisition signaling RES-ACK at BS place, the call admission administration module at BS place will return to a connection approval of the SS of this system signaling DSA-ACK after receiving RES-ACK, finish the connection of setting up data, services stream between BS and this SS;

5. after BS and SS set up data, services stream and are connected, QoS priority control module receives the application layer QoS demand signaling QoS-MES from high level periodically, DL-MAP/UL-MAP and data, services stream from the sub channel resource configuration module are submitted the scheduling feedback signaling SCH-MES that scheduler module is sent in the sub-plane, and according to the application layer QoS demand information of these signaling bears, user's subchannel unpaired message, the MSDU schedule information of all kinds of QoS and predefined QoS priority block strategy generate the PRI-MES signaling, are positioned at data, services and flow the QoS pri function value Φ of the dispatching sequence of all kinds of QoS MSDU in sub-plane by this signaling bear _{M, k, n}Determine that wherein, k is a customer identification number, m is any one in UGS, rtPS, ertPS, nrtPS and the BE type;

6. data, services stream is submitted the standard that several data processing module in the sub-plane is followed IEEE 802.16 standard formulations, according to the control information that managing signaling PRI-MES and DL-MAP/UL-MAP in the sub-plane of QoS resource management are carried all kinds of QoS data, services streams are classified, dispatched, realize successively submitting.

The present invention has following advantage:

1. the present invention has provided a kind of PMP WiMAX cross-layer structure that can effectively ensure QoS, because this framework realizes that in the sub-plane of QoS resource management QoS jointly controls, in data, services stream is submitted sub-plane, realize data processing and successively submit, therefore, simple in structure, function is well defined, and is specially adapted to actual engineering design.

2. the present invention is in the sub-plane of QoS resource management, by managing signaling a plurality of administration modules are united QoS control, can be in the maintenance system high throughput, data, services is flowed BER, time delay and transmission rate to be limited in the predetermined threshold value, also taken into account the fairness of system SS simultaneously, as Fig. 5, Fig. 6, Fig. 7 and shown in Figure 8 based on speed.

3. the present invention by adopting AMC mode selection module strategy, can select the modulation system of higher-order and higher code rate for use for the SS of system under desirable channel condition in the sub-plane of QoS resource management; Under less-than-ideal channel condition, select the modulation system of lower-order and lower code rate for use for the SS of system, when limiting BER, subchannel SNR and modulation system and code rate present one-to-one relationship, solved portable terminal multimedia communication problem of unstable under varying environment, different conditions to a great extent, as shown in Figure 5 and Figure 6.

4. the present invention is in the sub-plane of QoS resource management, by adopting sub channel resource configuration module strategy, having loosened " the transient data transmission rate that all SS obtain in the system must equate " this absolute fairness limits, can utilize multi-user diversity to obtain the higher system throughput based on AMC mechanism, take into account the fairness of the SS of system simultaneously, as Fig. 5, Fig. 6 and shown in Figure 7, this design complexities is lower, is specially adapted to practical engineering application.

5. the present invention is in the sub-plane of QoS resource management, by adopting QoS priority block strategy, the dispatching sequence who can the control data service flow submits each MSDU of QoS type buffer team in the sub-plane, hang down threshold value at the SS of system acceptable the QoS Properties Control that all kinds of connections obtain, as shown in Figure 8, QoS pri function model is simple, and its parameter designing is an open problem, can set flexibly at expectation of Virtual network operator profit or user's request.

Description of drawings

Fig. 1 is existing P MP WiMAX network topology structure figure;

Fig. 2 is existing desirable wireless network cross-layer structure figure;

Fig. 3 is the Data Control plane basic block diagram of IEEE 802.16 standard definitions;

Fig. 4 is the WiMAX cross-layer structure block diagram of the guaranteed qos that provides of the present invention;

Fig. 5 is that the SS of system number is 10 o'clock, the simulation curve figure that throughput of system changes with average SNR when adopting different control method;

Fig. 6 be when adopting different control method system's average throughput along with the simulation curve figure of SS number of variations;

Fig. 7 is that system QoS is violated the simulation curve figure of probability along with the SS number of variations when adopting different control method;

Fig. 8 be when adopting different control method the FI of system along with the simulation curve figure of SS number of variations.

Embodiment

1. term explanation

WiMAX: global inserting of microwave interoperability

PMP: put multiple spot

WMAN: wireless MAN

BS: base station

SS: subscriber station

QoS: service quality

OSI: Open System Interconnection

MAC: media access control layer

PHY: physical layer

SC: single carrier

SCa: single carrier inserts

OFDM: OFDM

OFDMA: OFDM inserts

TDD: time division duplex

FDD: Frequency Division Duplexing (FDD)

Half-FDD: Half-Frequency Division Duplex

CS: serve specific convergence sub-layer

CPS: common part sublayer

SAP: Service Access Point

MSDU:MAC layer service data unit

SFID: service flow sign

CID: connection identifier

UGS: unsolicited grant service

RtPS: real-time polling service

ErtPS: Extended real-time Polling Service

NrtPS: non-real-time polling service

BE: Best-Effort service

TCP: transmission control protocol

UDP: User Datagram Protoco (UDP)

IP: Internet protocol

IntServ: integrated service

DiffServ: and Differentiated Services

AMC: Adaptive Modulation and Coding

CQI-REQ: channel status probe requests thereby signaling

CQI-RSP: channel status probe response signaling

CQI-ACK: channel status is surveyed feedback signaling

DSA-REQ: call admission request signaling

DSA-RSP: call admission response signaling

DSA-ACK: call admission is replied signaling

AMC-REQ:AMC mode request signaling

AMC-RSP:AMC mode response signaling

RES-REQ: sub channel resource configuring request signaling

RES-RSP: sub channel resource configuration response signaling

DL-MAP/UL-MAP: sub channel resource configuration signal

AMC-MES:AMC model selection signaling

QoS-MES: application layer QoS demand signaling

PRI-MES:QoS priority control signaling

SCH-MES: scheduling feedback signaling

BER: bit error rate

SNR: signal to noise ratio

MSNR: maximization signal to noise ratio

WRR: weighted round robin

FI: fairness index

2. execution mode

Below in conjunction with accompanying drawing the solution of the present invention and effect are done and to be described in further detail:

With reference to Fig. 4, the present invention is based on layer design of striding of IEEE802.16 standard, the WiMAX basic data control plane comprises PHY layer, MAC layer and high level, and vertically is divided into two big sub-planes according to function: sub-plane of QoS resource management and data, services stream are submitted sub-plane.For ease of research, the present invention is referred to as high level with the above protocal layers of WiMAX MAC layer, and this layer mainly is responsible for the generation of various application and multimedia communication service flow, also the Security Sublayer that has nothing to do with the QoS guarantee in the MAC layer is ignored.The sub-plane of QoS resource management is adopted and is striden the corporate management control that layer thought realizes safeguards system QoS, comprise a plurality of QoS administration modules, it is channel status detecting module/feedback module, the AMC mode selection module, the sub channel resource configuration module, call admission administration module and QoS priority control module, these modules are by various managing signaling coordinate operation, control is high-rise transmits the application layer QoS demand of all kinds of multimedia communication service flow to the MAC layer, to the transmission of MAC layer, the QoS performance index that data, services stream is obtained are limited in the system user preset threshold control PHY layer with the subchannel AMC model selection information collected.The main function that data, services flows sub-plane is to carry out data processing also to realize successively submitting, comprise a plurality of data, services stream processing modules, be multimedia communication service flow generation module, SFID-CID mapping block, scheduler module, segmentation/one-tenth frame module, series connection/remove serial module structure and become frame module, these modules are followed the standard of IEEE802.16 standard formulation, and the Various types of data service flow is classified and dispatch according to the control information of managing signaling carrying in the sub-plane of QoS resource management, realization is successively submitted.Managing signaling in the sub-plane of QoS resource management comprises: the 1) signaling of transmitting between the asymmetrical QoS administration module on the different agreement layer in similar sub-plane, be called again and stride a layer signaling, such signaling comprises: AMC model selection signaling AMC-MES and application layer QoS demand signaling QoS-MES; 2) signaling of in similar sub-plane, transmitting between the reciprocity QoS administration module on the same protocol layer, such signaling comprises: channel status probe requests thereby signaling CQI-REQ, channel status probe response signaling CQI-RSP, channel status are surveyed feedback signaling CQI-ACK, call admission request signaling DSA-REQ, call admission response signaling DSA-RSP and call admission and are replied signaling DSA-ACK; 3) signaling of in similar sub-plane, transmitting between the asymmetrical QoS administration module on the same protocol layer, such signaling comprises: AMC mode request signaling AMC-REQ, AMC mode response signaling AMC-RSP, sub channel resource configuring request signaling RES-REQ, sub channel resource configuration response signaling RES-RSP and sub channel resource configuration signal DL-MAP/UL-MAP; 4) signaling of transmitting between the asymmetrical QoS administration module on the same protocol layer in the sub-plane of difference, such signaling comprises: QoS priority control signaling PRI-MES and scheduling feedback signaling SCH-MES.The direction of transfer of these managing signalings is shown in Fig. 4 dotted arrow.

QoS combination control method based on above-mentioned cross-layer structure comprises the steps:

The channel status detecting module at step 1:BS place obtains the channel condition information of the SS of system.

The channel status detecting module that is positioned at the BS place is broadcast probe request signaling CQI-REQ periodically, the channel state feedback module that is positioned at each SS place receives after this signaling that loopback CQI-RSP in response immediately, and channel SNR surveyed, the channel state feedback module sends the CQI-ACK that carries this SNR information by the channel status detecting module of based on feedback link to the BS place.

The AMC mode selection module at step 2:BS place generates AMC model selection aggregate information.

The AMC mode selection module that is positioned at the BS place sends demand signalling AMC-REQ periodically to the channel status detecting module, behind the response signaling AMC-RSP that receives the loopback of channel status detecting module, according to the signal to noise ratio aggregate information { SNR of this signaling bear _{K, n}| k=1,2 ..., K ﹠amp; N=1,2 ..., N} and predefined AMC model selection strategy generate AMC model selection aggregate information { l _{K, n}| k=1,2 ..., K ﹠amp; N=1,2 ..., N} promptly when the PHY layer adopts TDD-OFDMA based on subchannel transmission, supposes that the SS of system number is K, and number of subchannels is N, and the BER threshold value is certain, according to SNR _{K, n}Residing signal to noise ratio interval query AMC modal sets form can obtain model selection grade l _{K, n}, AMC modal sets form is referring to table 1.In the table 1, R _{PHY, k, n, l}Be the PHY layer normalization channel capacity of user k on subchannel n, R _{C, k, n, l}Be code rate, R _{PHY, k, n, l}And R _{C, k, n, l}By l _{K, n}Decision; R _{MAC, k, n, l}For the MAC layer transmission rate of user k on subchannel n, by R _{PHY, k, n, l}And R _{C, k, n, l}Calculate acquisition according to (1) formula.

In the formula, Bsub is a subchannel bandwidth,

The maximum integer that is less than or equal to value is got in expression.

Table 1 AMC modal sets

The sub channel resource configuration module at step 3:BS place generates user's subchannel pairing aggregate information.

The AMC mode selection module that is positioned at the BS place sends layer signaling AMC-MES that stride that carries AMC model selection aggregate information periodically to the sub channel resource configuration module, the AMC mode selection module generates user's subchannel pairing aggregate information { C according to AMC model selection aggregate information and predefined sub channel resource configuration module strategy _{K, n, l}| k=1,2 .., K ﹠amp; N=1,2 ..., N}, the sub channel resource configuration module generates DL-MAP and UL-MAP according to user's subchannel pairing set ground information cycle, and the one-tenth frame module that data, services stream is submitted in the sub-plane encapsulates and framing downlink burst stream and uplink burst stream according to this two classes signaling.The generative process of user's subchannel pairing aggregate information is as follows:

1) is assumed to the number of subchannels N that each SS distributes _kCan obtain by formula (2):

In the formula, ξ _kFor the system resource of SS k takies the factor, N is system's number of subchannels, and K is the SS of a system number.

2) the SS k number of subchannels N that determines according to step 1) _k, for each SS k picks out N from N ' _kIndividual subchannel is used for transfer of data:

2a) all variablees of initialization:

$\begin{array}{cc}{R}_{\mathrm{MAC},k}=0& \∀k\∈\{\mathrm{1,2},...,K\}\end{array}$

N′＝{1，2，...，N}

K′＝{1，2，...，K}

Wherein, C _{K, n, l}Be user's subchannel pairing identifier, when user k obtains l _{K, n}During level subchannel n, C _{K, n, l,}Value is 1; When user k does not obtain subchannel n, C _{K, n, l}Value is 0, R _{MAC, k}Be the MAC layer instantaneous transmission speed on the user k, N ' is unappropriated sets of sub-channels still, and K ' is for waiting for user's set of allocated sub-channels resource.

2b) distribute l for each SS _{K, n}The highest idle sub-channels:

The search l from k=1 to the K ascending order _{K, n}, order $n=\arg \underset{n\∈N}{\max }{l}_{k,n},$ And have:

C _k，n，l＝1，N _k＝N _k-1，N′＝N′/{n}，R _MAC，k＝R _MAC，k+R _{MAC，k，n，l}

Wherein, N ' n} represent from the set N ' removal element n, R _{MAC, k, n, l}Be the MAC layer transmission rate of user k on subchannel n.

If 2c) number of subchannels of SS k acquisition does not reach N as yet _k, will be R in the sub-channel assignment procedure every the wheel _{MAC, k}Minimum user k selects l _{K, n}The highest subchannel n is used for the data, services flow transmission, and process is as follows:

At first, for satisfying The user k to be allocated of condition obtains to select subchannel $n=\arg \underset{n\∈N}{\max }{l}_{k,n}$ Preferential right, if N _k0, user k just can obtain this subchannel n, i.e. C _{K, n, l}=1, and the subchannel n that will distribute from the set N ' removal, promptly N '=N ' { n}; Then, upgrade the number of subchannels to be allocated of user k, i.e. Nk=Nk-1 upgrades the instantaneous MAC layer transmission rate of user k, i.e. RMAC, k=R _{MAC, k}+ R _{MAC, k, n, l}

Constantly repeat the above-mentioned process of selecting, will satisfy N earlier before each is taken turns and selects _k=0 user removes from user to be allocated set, promptly K '=K ' { k} is until set

Wherein, K ' k} represent from the set K ' removal element k.

3) if N ^*≠ 0, residue N ^*The allocation strategy of individual subchannel is:

3a) reinitialize variable:

K '=and 1,2 ..., K}3b) set each user and only can obtain N ^*1 subchannel in the individual subchannel, and from n=1 to N ^*Ascending order search l _{K, n}, for satisfying $k=\arg \underset{k\∈K}{\max }{l}_{k,n}$ The user k to be allocated of condition will obtain subchannel n, i.e. C _{K, n, l}=1, and this user k gathered removal the K ' from user to be allocated, promptly K '=K ' { k} constantly repeats this sub-channel assignment procedure, until set Wherein, $N^{*}=N-{\mathrm{\Σ}}_{k=1}^K{N}_k,$ It is through still unappropriated number of subchannels after the step 7.2.

Step 4: set up BS and be connected with the data, services stream of the SS of system.

After a certain SS in BS and the system sets up synchronously, the call admission administration module of call admission administration module to the BS place that is positioned at this SS place sends call admission request signaling DSA-REQ periodically, BS at first sends the DSA-RSP signaling as response after receiving this signaling, send resource query signaling RES-REQ to the sub channel resource configuration module then, when sub channel resource configuration module completing steps 3, again to the call admission administration module loopback resource acquisition signaling RES-ACK at BS place, the call admission administration module at BS place will return to a connection approval of the SS of this system signaling DSA-ACK after receiving RES-ACK, finish the connection of setting up data, services stream between BS and this SS.

Step 5: the dispatching sequence who submits all kinds of MPDU in the sub-plane according to QoS priority control module strategy specified data service flow.

After BS and SS set up data, services stream and are connected, QoS priority control module receives the application layer QoS demand signaling QoS-MES from high level periodically, DL-MAP/UL-MAP and data, services stream from the sub channel resource configuration module are submitted the scheduling feedback signaling SCH-MES that scheduler module is sent in the sub-plane, and according to the application layer QoS demand information of these signaling bears, user's subchannel unpaired message, the MSDU schedule information of all kinds of QoS and predefined QoS priority block strategy generate the PRI-MES signaling, are positioned at data, services and flow the QoS pri function value Φ of the dispatching sequence of all kinds of QoS MSDU in sub-plane by this signaling bear _{M, k, n}Determine that wherein, k is a customer identification number, m is any one in UGS, rtPS, ertPS, nrtPS and the BE type.Scheduling constantly, data, services stream submits that to be under the jurisdiction of user k, type in the sub-plane be that the dispatching sequence of MSDU on subchannel n of m is by Φ _{M, k, n}Determine, that is:

Φ _{M, k, n}=β _mσ _{M, k, n}β _m≤ 1 and σ _{M, k, n}≤ 1 (3)

In the formula (3), β _mFor QoS COS weight, provide by QoS-MES, be used for characterizing the significance level that MSDU to be dispatched is subordinate to COS, β _mValue is big more, shows that the dispatching priority of such MSDU is high more; σ _{M, k, n}Be QoS performance index weight, determine jointly, be used for characterizing MSDU to be dispatched and be subordinate to the degree that the QoS demand is satisfied in connection, σ by QoS-MES, DL-MAP/UL-MAP and SCH-MES loaded information _{M, k, n}Value is big more, shows that the probability of this MSDU violation QoS is big more, and corresponding dispatching priority is high more.

Below provided two kinds of QoS priority control strategies that are applicable to this cross-layer structure:

1), σ is arranged all to any m _{M, k, n}=1, this is a kind of the simplest weighted Q oS priority control strategy.In function phi _{M, k, n}=β _m(β _m≤ 1) under the control, is positioned at data, services stream and submits the scheduler module on sub-plane and can adopt weighted round robin WRR scheduling mode fixedly classification of all kinds of MSDU, β _mIn case determine, for example, β _RtPS=1, β _NrtPS=0.8, β _BE=0.6, the dispatching sequence of every class MSDU will no longer change.This QoS priority control strategy can guarantee that the high application level service stream of rank obtains QoS performance preferably, but can cause the resource distribution injustice of types of applications level service flow, and the application level service stream that rank is lower can't obtain QoS performance assurance preferably.

2), σ is arranged all to any m _{M, k, n}≤ 1, this is a kind of Adaptive QoS priority control strategy.In function phi _{M, k, n}=β _mσ _{M, k, n}(β _m≤ 1) under the control, is positioned at the scheduler module that data, services stream is submitted sub-plane, dynamically adjusts the dispatching sequence of all kinds of service buffer MSDU of squadron according to QoS pri function value.COS m difference, σ _{M, k, n}Definition is different, is example with rtPS, nrtPS and BE service, σ _{RtPS, k, n}, σ _{NrtPS, k, n}And σ _{BE, k, n}Available formula (4), formula (5) and formula (6) expression respectively:

σ _BE，k，n＝1(6)

Wherein, in the formula (4), T _RtPSBe the delay requirement of rtPS service flow, W _RtPSBe the wait time delay of the rtPS COS buffer MSDU of team in buffer, Δ T _RtPSFor rtPS guard time interval, be made as frame length usually; In the formula (5), R _{NrtPS, MAC, min}Be the minimum reserved rate requirement of nrtPS service flow, R _{NrtPS, MAC}For being subordinate to, the nrtPS COS buffer MSDU of team is connected scheduling average transmission rate constantly, available formula (7) expression:

${\stackrel{\‾}{R}}_{\mathrm{nrtPS},\mathrm{MAC}}={\stackrel{\‾}{R\′}}_{\mathrm{nrtPS},\mathrm{MAC}}(1-1/t_c)+R_{\mathrm{nrtPS},\mathrm{MAC}}^{\′}(1/t_c)---\left(7\right)$

In the formula (7), t _cBe the time window size, R ＇ _{NrtPS, MAC}Represent that this MSDU is subordinate to the average transmission rate that is connected a scheduling moment,

Represent that this MPDU is subordinate to the instantaneous transmission speed that is connected a scheduling moment, satisfies formula (8):

$R_{\mathrm{nrtPS},\mathrm{MAC}}=\underset{n-1}{\overset{N}{\mathrm{\Σ}}}{C}_{k,n,l}{R}_{\mathrm{MAC},k,n,l}---\left(8\right)$

Described (4) formula can guarantee effectively that rtPS connects the satisfied time delay tolerance limit requirement of predesignating, described (5) formula can guarantee effectively that nrtPS connects the satisfied minimum reserved rate requirement of predesignating, and the BE business is to time delay and the equal no requirement (NR) of speed, so in (6) formula, σ _{BE, k, n}Perseverance is 1.

Step 6: in data, services stream is submitted sub-plane, finish all kinds of multimedia communications according to classification, the scheduling of service flow with successively submit.

Data, services stream is submitted the standard that several data processing module in the sub-plane is followed IEEE 802.16 standard formulations, with PMPWiMAX network down link is example, the control information that these modules are carried according to managing signaling PRI-MES and DL-MAP/UL-MAP in the sub-plane of QoS resource management, the process that all kinds of QoS data, services streams are classified, dispatched and realize successively submitting is as follows:

1) the higher layer applications level service flow at BS place, for example VoIP, MPEG and FTP at first enter MAC CS sublayer, and this sublayer is bound corresponding SFID and CID according to the service flow type for it, finish the mapping of SFID-CID, thereby application level protocol data cell PDU is converted into MSDU;

2) the IEEE802.16 standard series has defined 5 class QoS service, be respectively: UGS, rtPS, ertPS, nrtPS and BE, in MAC CPS sublayer, all corresponding 1 the type buffer queue of every class QoS service, after MSDU enters CPS, MSDU with identical SFID can enter in the same type buffer queue, CID has then write down these MSDU and has been under the jurisdiction of which bar which SS initiates respectively and communicates to connect, can see, descending submitting at BS CPS has 5 QoS type buffer queues on the direction, corresponding 5 mutually different SFID values;

3) in MAC CPS, carry the QoS pri function value information of the correct MSDU of each type buffer queue from the PRI-MES of the sub-plane of QoS resource management QoS priority control module, its dispatching sequence will be determined by this multidate information, the MSDU that is scheduled then can carry out segmentation/one-tenth piece according to pre-sizing, and is packaged into Medium Access Control (MAC) Protocol Data Unit MPDU;

4) several MPDU series connection backs form burst Burst, the time-frequency position that each burst Burst occupies in downlink subframe is to provide ground DL-MAP to determine by the sub-plane of the QoS resource management sub channel resource configuration module cycle, some burst Burst form PHY layer protocol data cell PPDU again through encapsulation, and broadcast to SS by wireless channel;

5) UL-MAP/DL-MAP has carried time-frequency positional information and the affiliated SS information of each burst in a frame, after each SS receives broadcast service stream, to from downlink subframe, obtain one's own burst flow according to the DL-MAP domain information in every frame, and submit to the SS high level.

Effect of the present invention can be described further by following emulation:

1. simulated conditions

Be the performance of each QoS module coordinate operation in the check cross-layer structure, the QoS combination control method that the present invention is adopted carries out emulation relatively with typical PMP WiMAX control method.It should be noted that, what the QoS combination control method was selected for use at the MAC layer is self-adaptation type QoS priority block strategy, typical PMP WiMAX control method typical case PMP WiMAX control based on IEEE 802.16 standards is adopted AMC model selection strategy and maximization signal to noise ratio strategy MSNR at the PHY layer, and changes team's head grouping that the RR mode is dispatched each QoS buffer queue at the MAC layer with wheel.The MSNR strategy is a kind of typical sub channel resource collocation strategy, can utilize the multi-user diversity gain maximum system throughput, basic thought is: each subchannel at first can be selected channel conditions the best, be that the highest SS formation user subchannel of SNR or lkn is right, if the service flow that arrives this SS is arranged, then subchannel can transmit this SS service flow, otherwise, search is had low one-level l _KnSS to constitute new subchannel user right.Though it is simple that above-mentioned MSNR strategy is implemented, and can make throughput of system reach maximum, be difficult to guarantee the fairness of serving cause minority to monopolize system resource easily, and that the SS that is located in cell edge obtains the probability of base station services is low near BS or the strong SS of signal.

2. simulation parameter is set

The service flow generating rate of the different SS of table 2 and QoS performance requirement

Table 3 system parameters

Suppose that analogue system is made of 1 SS and several SS, SS is with the 50km/h uniform motion.All have a rtPS connection, a nrtPS to connect and be connected with a BE on each SS, corresponding QoS COS weight is respectively: β _RtPS=1.0, β _NrtPS=0.8, β _BE=0.6.Among Fig. 4, the service flow generative process of high-rise multimedia communication service flow generator is obeyed Poisson distribution, and the service flow generating rate and the QoS performance requirement that are under the jurisdiction of different SS all have difference, referring to table 2.The present invention adopts continous way ContiguousFDMA subchannel constituted mode, and 1 Basic Transmission Unit Slot is definite jointly by the piece and the symbol Symbol of some, and each piece all comprises 9 subcarriers.The IEEE802.16 standard definition 4 kinds of system bandwidth: 1.25MHz, 5MHz, 10MHz and 20MHz, sub-carrier number is respectively: 128,512,1024 and 2048.For studying conveniently, the present invention selects 10MHz system bandwidth and 2 pieces, and 3 symbol combination are research object.Table 3 has provided all the other all system parameterss.

3. simulation performance relatively

Emulation has mainly been studied in the PMP WiMAX network based on the QoS combination control method of the cross-layer structure performance impact to system QoS guarantee, user fairness and throughput of system.For quantitative description performance of the present invention, adopt throughput of system, QoS violation probability and these three indexs of user fairness sex index FI that it is compared.

At first, the QoS combination control method that the present invention is based on cross-layer structure is carried out throughput performance relatively with typical PMP WiMAX control method.It is identical to suppose that each SS arrives the distance of BS, and promptly the average SNR that receives of each SS is identical, and it is the simulation curve figure of the throughput of system of 10 o'clock two kinds of methods with the channel changed condition that Fig. 5 has provided system SS number.Owing to introduced in PMP WiMAX and stride a layer QoS controlling mechanism, in the whole SNR zone, the throughput of system that obtains based on the QoS combination control method of cross-layer structure is all less than typical method, but is more or less the same.In 13dB SNR zone,, obtain fast lifting at specific 9dB based on the throughput of system of the QoS combination control method of cross-layer structure because the qos requirement that all kinds of services connect all is met.When the system user number constantly increases, Fig. 6 has compared the average system throughput of two kinds of schemes, as seen from Figure 6, increase along with number of users, system's average throughput of two kinds of methods all promotes to some extent, compares with typical method, guarantees and user fairness in order to obtain QoS, QoS combination control method based on cross-layer structure has been sacrificed the part throughput performance, and this also is inevitable result in the practical application.It should be noted that two kinds of methods have all adopted AMC model selection strategy at the PHY layer, so the two has all obtained the higher system throughput.

Then, the QoS combination control method that the present invention is based on cross-layer structure is carried out the SS of system fairness relatively with typical PMP WiMAX control method.Introduce fairness index FI as the index of investigating the SS of system fairness, FI is more near 1, and the fairness that illustrative system SS obtains is good more.Definition can be obtained by formula (9) based on the FI of speed:

$\mathrm{FI}=\frac{{\left(\underset{k=1}{\overset{K}{\mathrm{\Σ}}}{R}_{\mathrm{MAC},k}\right)}^2}{K\underset{k=1}{\overset{K}{\mathrm{\Σ}}}{\left(R_{\mathrm{MAC},k}\right)}^2}---\left(9\right)$

In the formula, R _{MAC, k}Be the instantaneous MAC layer transmission rate of user k, can calculate acquisition by formula (10):

Fig. 7 has provided the situation of the FI curve of two kinds of schemes with the SS of system number K variation.As seen from Figure 7 along with the increase gradually of the SS of system number, constantly rise based on the FI of the QoS combination control method of cross-layer structure, compare with typical PMPWiMAX control method, system can obtain better the user fairness based on speed.

At last, the QoS combination control method that the present invention is based on cross-layer structure is carried out the QoS performance relatively with typical PMPWiMAX control method.The QoS that Fig. 8 has provided two kinds of methods violates the probabilistic simulation curve, and rtPS class service flow and nrtPS class service flow are corresponding respectively, and maximum delay violation probability and minimum reserved rate are violated probability.As seen from Figure 8, the QoS that obtains based on the QoS combination control method of cross-layer structure violates probability well below typical PMP WiMAX control method.Though still can bring lower QoS to violate probability, this is complete acceptable result in actual applications, therefore the QoS combination control method based on cross-layer structure can effectively guarantee the QoS performance that all kinds of services connect.

Claims (10)

1. the cross-layer structure of guaranteed qos among the WiMAX, comprise PHY layer, MAC layer and high level, these three layers formation WiMAX basic data control plane is characterized in that whole WiMAX basic data control plane vertically is divided into the sub-plane of QoS resource management and data, services stream is submitted sub-plane;

The sub-plane of described QoS resource management, contain the different QoS administration module of multiple function, these modules are by various managing signaling coordinate operation, control is high-rise transmits the application layer QoS demand of all kinds of multimedia communication service flow to the MAC layer, to the transmission of MAC layer, the QoS performance index that data, services stream is obtained are limited in the system user preset threshold control PHY layer with the subchannel AMC model selection information collected;

Described data, services stream is submitted sub-plane, contain the different data, services stream processing module of multiple function, these modules are followed the standard of IEEE 802.16 standard formulations, and according to the control information of managing signaling carrying in the sub-plane of QoS resource management the Various types of data service flow is classified, dispatch, realization is successively submitted.

2. cross-layer structure according to claim 1 is characterized in that described QoS administration module comprises channel status detection/feedback module, AMC mode selection module, sub channel resource configuration module, call admission administration module and QoS priority control module; Described data, services stream processing module comprises multimedia communication service flow generation module, SFID-CID mapping block, scheduler module, segmentation/one-tenth frame module, series connection/remove serial module structure and become frame module.

3. cross-layer structure according to claim 1 is characterized in that described managing signaling comprises:

3.1) signaling in similar sub-plane, transmitted between the asymmetrical QoS administration module on the different agreement layer, being called again and striding a layer signaling, such signaling comprises: AMC model selection signaling AMC-MES and application layer QoS demand signaling QoS-MES;

3.2) signaling transmitted between the reciprocity QoS administration module in similar sub-plane on the same protocol layer, such signaling comprises: channel status probe requests thereby signaling CQI-REQ, channel status probe response signaling CQI-RSP, channel status are surveyed feedback signaling CQI-ACK, call admission request signaling DSA-REQ, call admission response signaling DSA-RSP and call admission and are replied signaling DSA-ACK;

3.3) signaling transmitted between the asymmetrical QoS administration module in similar sub-plane on the same protocol layer, such signaling comprises: AMC mode request signaling AMC-REQ, AMC mode response signaling AMC-RSP, sub channel resource configuring request signaling RES-REQ, sub channel resource configuration response signaling RES-RSP and sub channel resource configuration signal DL-MAP/UL-MAP;

3.4) signaling transmitted between the asymmetrical QoS administration module in the sub-plane of difference on the same protocol layer, such signaling comprises: QoS priority control signaling PRI-MES and scheduling feedback signaling SCH-MES.

4. the QoS combination control method based on cross-layer structure comprises the steps:

4.1) the channel status detecting module that is positioned at BS place broadcast probe request signaling CQI-REQ periodically, the channel state feedback module that is positioned at each SS place receives after this signaling that loopback CQI-RSP in response immediately, and channel SNR surveyed, the channel state feedback module sends the CQI-ACK that carries this SNR information by the channel status detecting module of based on feedback link to the BS place;

4.2) the AMC mode selection module that is positioned at the BS place sends demand signalling AMC-REQ periodically to the channel status detecting module, behind the response signaling AMC-RSP that receives the loopback of channel status detecting module, according to the signal to noise ratio aggregate information { SNR of this signaling bear _{K, n}| k=1,2 ..., K ﹠amp; N=1,2 ..., N} and predefined AMC model selection strategy generate AMC model selection aggregate information { l _{K, n}| k=1,2 ..., K ﹠amp; N=1,2 ..., N};

4.3) the AMC mode selection module that is positioned at the BS place sends layer signaling AMC-MES that stride that carries AMC model selection aggregate information periodically to the sub channel resource configuration module, the AMC mode selection module generates user's subchannel pairing aggregate information { C according to AMC model selection aggregate information and predefined sub channel resource configuration module strategy _{K, n, l}| k=1,2 ..., K ﹠amp; N=1,2 ..., N}, the sub channel resource configuration module generates DL-MAP and UL-MAP according to user's subchannel pairing set ground information cycle, and the one-tenth frame module that data, services stream is submitted in the sub-plane encapsulates and framing downlink burst stream and uplink burst stream according to this two classes signaling;

4.4) after a certain SS in BS and the system sets up synchronously, the call admission administration module of call admission administration module to the BS place that is positioned at this SS place sends call admission request signaling DSA-REQ periodically, BS at first sends the DSA-RSP signaling as response after receiving this signaling, send resource query signaling RES-REQ to the sub channel resource configuration module then, when the sub channel resource configuration module finishes the 4.3rd) step, again to the call admission administration module loopback resource acquisition signaling RES-ACK at BS place, the call admission administration module at BS place will return to a connection approval of the SS of this system signaling DSA-ACK after receiving RES-ACK, finish the connection of setting up data, services stream between BS and this SS;

4.5) after BS and SS set up data, services stream and be connected, QoS priority control module receives the application layer QoS demand signaling QoS-MES from high level periodically, DL-MAP/UL-MAP and data, services stream from the sub channel resource configuration module are submitted the scheduling feedback signaling SCH-MES that scheduler module is sent in the sub-plane, and according to the application layer QoS demand information of these signaling bears, user's subchannel unpaired message, the MSDU schedule information of all kinds of QoS and predefined QoS priority block strategy generate the PRI-MES signaling, are positioned at data, services and flow the QoS pri function value Φ of the dispatching sequence of all kinds of QoS MSDU in sub-plane by this signaling bear _{M, k, n}Determine that wherein, k is a customer identification number, m is any one in UGS, rtPS, ertPS, nrtPS and the BE type;

4.6) data, services stream submits the standard that several data processing module in the sub-plane is followed IEEE 802.16 standard formulations, according to the control information that managing signaling PRI-MES and DL-MAP/UL-MAP in the sub-plane of QoS resource management are carried all kinds of QoS data, services streams are classified, dispatched, realize successively submitting.

5. QoS combination control method according to claim 4, wherein step 4.2) described AMC model selection aggregate information { l _{K, n}| k=1,2 ..., K ﹠amp; N=1,2 ..., N} is the signal to noise ratio aggregate information { SNR that provides according to CQI-MES _{K, n}| k=1,2 ..., K ﹠amp; N=1,2 ..., N} and predefined AMC model selection strategy determine, promptly when PHY layer employing during based on the OFDMA of subchannel transmission, supposes that the SS of system number is K, and number of subchannels is N, and the BER threshold value is certain, according to SNR _{K, n}Residing signal to noise ratio interval query AMC modal sets form obtains model selection grade l _{K, n}

6. QoS combination control method according to claim 4, wherein step 4.3) described user's subchannel pairing aggregate information { C _{K, n, l}| k=1,2 ..., K ﹠amp; N=1,2 ..., N} is according to AMC model selection aggregate information and predefined sub channel resource configuration module strategy, determines as follows:

6.1) set the number of subchannels N that each SS distributes _kFor:

In the formula, ξ _kFor the system resource of SSk takies the factor, N is system's number of subchannels, and K is the SS of a system number;

6.2) according to the SS k number of subchannels N that determines _k, for each SS k picks out N from N ' _kIndividual subchannel is used for transfer of data, and wherein, N ' is unappropriated sets of sub-channels still;

6.3) set $N^{*}=N-{\mathrm{\Σ}}_{k=1}^K{N}_k$ Be remaining number of subchannels, if N ^*≠ 0, for each user from N ^*Pick out 1 subchannel in the individual subchannel and be used for the data, services flow transmission.

7. QoS combination control method according to claim 6, wherein step 6.2) describedly from N ', pick out N for each SS k _kIndividual subchannel is used for transfer of data, selects as follows:

7.1) all variablees of initialization:

C _k，n，l＝0?

R _MAC，k＝0? $\∀k\∈\{\mathrm{1,2},...,K\}$

N′＝{1，2，...，N}

K′＝{1，2，...，K}

Wherein, C _{K, n, l}Be user's subchannel pairing identifier, when user k obtains l _{K, n}During level subchannel n, C _{K, n, l}Value is 1; When user k does not obtain subchannel n, C _{K, n, l}Value is 0, R _{MAC, k}Be the MAC layer instantaneous transmission speed on the user k, K ' is for waiting for user's set of allocated sub-channels resource;

7.2) be that each SS distributes l _{K, n}The highest idle sub-channels:

The search lk from k=1 to the K ascending order, n, order $n=\arg \underset{n\∈N}{\max }{l}_{k,n},$ And have:

$C_{k,n,l}=1,N_k=N_k-1,N\′=N\′/\left\{n\right\},R_{\mathrm{MAC},k}=R_{\mathrm{MAC},k}+R_{\mathrm{MAC},k,n,l}$

Wherein, N ' n} represent from the set N ' removal element n, R _{MAC, k, n, l}Be the MAC layer transmission rate of user k on subchannel n;

7.3) if the number of subchannels that SS k obtains does not reach N as yet _k, will be R in the sub-channel assignment procedure every the wheel _{MAC, k}Minimum user k selects l _{K, n}The highest subchannel n is used for the data, services flow transmission.

8. QoS combination control method according to claim 6, wherein step 6.3) described be that each user is from N ^*Pick out 1 subchannel fourth data, services flow transmission in the individual subchannel, select as follows:

8.1) reinitialize variable:

K′＝{1，2，...，K}

8.2) set each user for each and only can obtain N ^*1 subchannel in the individual subchannel, and from n=1 to N ^*Ascending order search l _{K, n}, for satisfying $k=\arg \underset{k\∈K}{\max }{l}_{k,n}$ The user k to be allocated of condition will obtain subchannel n, i.e. C _{K, n, l}=1, and this user k gathered removal the K ' from user to be allocated, promptly K '=K ' { k} constantly repeats this sub-channel assignment procedure, until set

9. QoS combination control method according to claim 7, wherein step 7.3) describedly be R every take turns in the sub-channel assignment procedure _{MAC, k}Minimum user k selects l _{K, n}The highest subchannel n, step is as follows:

9.1) for satisfying $k=\arg \underset{k\∈K}{\min }{R}_{\mathrm{MAC},k}$ ﹠amp; The user k to be allocated of k ∈ K ' condition obtains to select subchannel $n=\arg \underset{n\∈N}{\max }{l}_{k,n}$ Preferential right, if N _k0, user k just can obtain this subchannel n, i.e. C _{K, n, l}=1, and the subchannel n that will distribute from the set N ' removal, promptly N '=N ' { n};

9.2) upgrade the number of subchannels to be allocated of user k, i.e. N _k=N _k-1, the instantaneous MAC layer transmission rate of renewal user k, i.e. R _{MAC, k}=R _{MAC, k}+ R _{MAC, k, n, l}

Constantly repeat the above-mentioned process of selecting, will satisfy N earlier before each is taken turns and selects _k=0 user removes from user to be allocated set, promptly K '=K ' { k} is until set Wherein, K ' k} represent from the set K ' removal element k.

10. QoS combination control method according to claim 4, wherein step 4.5) described QoS priority control module strategy is to use pri function Φ _{M, k, n}Characterize, in scheduling constantly promptly, data, services stream submits that to be under the jurisdiction of user k, type in the sub-plane be that the dispatching sequence of MSDU on subchannel n of m is by Φ _{M, k, n}Determine, that is:

Φ _{M, k, n}=β _mσ _{M, k, n}β _m≤ 1 and σ _{M, k, n}≤ 1

In the formula, β _mFor QoS COS weight, provide by QoS-MES, be used for characterizing the significance level that MSDU to be dispatched is subordinate to COS, β _mValue is big more, shows that the dispatching priority of such MSDU is high more; σ _{M, k, n}Be QoS performance index weight, determine jointly, be used for characterizing MSDU to be dispatched and be subordinate to the degree that the QoS demand is satisfied in connection, σ by QoS-MES, DL-MAP/UL-MAP and SCH-MES loaded information _{M, k, n}Value is big more, shows that the probability of this MSDU violation QoS is big more, and corresponding dispatching priority is high more.

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