CN1274167C - Fair scheduling method based on priority level - Google Patents

Abstract

The present invention relates to a fair scheduling method based on priorities, which can enhance the transmission efficiency of a system, improve fairness among users and ensure user service quality requirements. The realization process of the method comprises the following a plurality of steps: maximum data transmission quantity corresponding to the signal-to-noise ratio is calculated in each operation cycle and is saved in a parameter table form; system operation cost generated by user data waiting time t is calculated; the corresponding maximum data transmission quantity thi(t) is searched in the table stored in first step according to the estimation value of a channel to the signal-to-noise ratio; a smaller value in the maximum data transmission quantity and the waiting data quantity is the data quantity transmitted in the next operation cycle by the system; P_waiti(t) obtains time delay cost by the rule 2 for each user; the communication system transmits data to the user with highest PRIi(t) in the next operation cycle to finish one-time scheduling process; the scheduling method repeats the steps from the second step to the fifth step in the operation cycle every time.

Description

Dispatching method based on priority

Technical field

The present invention is a kind of method that is used for the mobile communication system wireless resource scheduling, belongs to RRM research field in the mobile communication system.

Background technology

Mobile communication develops rapidly in the world, and data service will replace the main business that voice service becomes mobile communication.The transmission rate of data service will dynamic change on a large scale; Compare with the general ip data service, data service is responsive more to the requirement of propagation delay time.Therefore, the professional transmission requirement that need to use flexibly, allocation of radio resources and management method adapts to mobile communication system efficiently.Traditional radio resource management method mainly uses power control and rate controlled, channel allocation, scheduling, access control, switching controls, radio link adaptation, independently allotment and management algorithm separately such as QoS end to end, is optimized design at the use of mobile communication system and Radio Resource thereof.The wireless resource management algorithm of common various optimizations has improved systematic function to a certain extent, and each algorithm can adopt lower static method of computational complexity or the higher dynamic approach of complexity to realize the management and the allotment of Radio Resource.Use treatment technology, multi-carrier modulation technology when empty in the future mobile communication system and comprise the novel radio transmission technologys such as mixing multiple access technology of time domain, frequency domain, sign indicating number territory, spatial domain, make the Radio Resource of wireless system air interface present the multidimensional characteristic.Therefore, need consider that at the RRM of future mobile communication system making the use of Radio Resource can be adapted to service bearer towards the rational allocation of multidimensional Radio Resource requires variation with quality of wireless channel, to improve the availability of frequency spectrum and shared to greatest extent Radio Resource.

Summary of the invention

Technical problem: the purpose of this invention is to provide and a kind ofly can improve the mobile communication system efficiency of transmission, improve fairness between the user, ensure the equity dispatching method that QoS of customer (QoS) requires based on priority.

Technical scheme: the equity dispatching method based on priority of the present invention, according to each user since user data wait for system operation cost that time delay produces and next cycle of operation system and the user between can data quantity transmitted situation adjust user's dispatching priority, the dispatching priority according to each user's correspondence dynamically changes Resource Allocation Formula again.

Dispatching priority is to be positioned at the stand-by period of user's waiting list head of the queue packet and user's respective channels can correctly send data volume in the next cycle of operation mathematical function.Can correctly send data volume and be meant that channel is at the next cycle of operation data volume that can transmit and the smaller value of waiting for data volume.

Scheme operation idiographic flow is as follows:

The 1st step: the estimated value γ of the channel signal to noise ratio that bandwidth B that takies based on mobile communication system and channel estimating apparatus estimate, foundation

C=τ Blog (1+ γ) [rule 1]

Calculate each corresponding channel of different numerical value channel signal to noise ratios with each can transmit in each cycle of operation length maximum amount of data and preserve with the parameter list form, in rule 1, τ is the length of each cycle of operation, can be slot length or transmission frame length, C is the mobile communication system maximum amount of data that channel can transmit in cycle of operation length, B is system's occupied bandwidth, and γ is the estimated value of channel signal to noise ratio;

The 2nd step: at moment t, according to what concern between the system operation cost P_wait (t) that characterizes user data stand-by period and generation

$P_{-}\mathrm{wait}\left(t\right)=\frac{2\·(P_2-P_1)}{D}\×t+\frac{3\·P_1-P_2}{2}$

[rule 2]

Calculate because the system operation cost that user data stand-by period t produces, in rule 2, D is that (t≤D), P1 and P2 are the system operation cost that user data produces when waiting for time of D/4 and 3D/4 for the maximum latency of user data;

The 3rd step is at moment t, according to the estimated value γ of each user's channel signal to noise ratio _iFrom the form of the 1st step preservation, search the maximum amount of data C that corresponding channel can transmit _i(t), according to

Th _i(t)=min{C _i(t), S _i(t) } [rule 3]

The maximum amount of data C that channel can transmit _i(t) wait for data volume S with the user _i(t) smaller value is exactly can data quantity transmitted th between next one cycle of operation system and user _i(t);

The 4th step, according to

PRI _i(t)=th _i(t) P_wait _i(t) [rule 4]

Calculate each Subscriber Queue dispatching priority, in rule 3, PRI _i(t) be user's dispatching priority, th _i(t) be obtained in the 3rd step next cycle of operation system and the user between can data quantity transmitted, P_wait _i(t) draw according to rule 2 because user data is waited for the system operation cost that time delay produces at each user;

In the 5th step, in the next cycle of operation, communication system is PRI _i(t) the highest user is transmitted data, finishes scheduling process one time;

Each dispatching method is to repeat the above the 2nd to the 5th to go on foot in each cycle of operation.

Beneficial effect: the dispatching algorithm based on priority of the present invention can improve system transmissions efficient, improves fairness between the user, ensures QoS of customer (QoS) requirement.The groundwork of algorithm is the dispatching priority that calculates the user, after the method for use look-up table is simplified processing, only needs at initial phase relevant parameter to be calculated storage, and complexity is not high in the real system running.

Description of drawings

Fig. 1 is that the present invention program moves the idiographic flow schematic diagram.

Fig. 2 is based on the scheduling scheme implement device schematic diagram of priority, is calculated with formation choice device three parts by channel estimating apparatus, waiting list supervising device, dispatching priority and forms.

Embodiment

Fig. 2 has provided the implement device of this method, estimate the signal to noise ratio of channel by channel estimating apparatus, the waiting list monitoring device is responsible for monitoring the data stand-by period and the individual queue wait data quantity transmitted of each waiting list, and dispatching priority calculates and is used for calculating the corresponding dispatching priority of each waiting list and provides service according to the one or more formations of priority selective sequential from high to low with the formation choice device.

The calculating of dispatching priority is the key of whole algorithm.In the present invention, user's dispatching priority is to wait for the data volume decision that can correctly send between system operation cost that time delay produces and system and the user by the user data of individual queue.

Each scheduling only needs to select from waiting list the user with limit priority to serve.

The specific implementation step:

Initialization system has the individual user of m (m＞0).System's occupied bandwidth is B (Hz), and cycle of operation length is 10ms, and the channel signal to noise ratio that the channel status estimation unit obtains has 16, and note is made γ 1, and γ 2 ..., γ 16; The user data maximum wait transmission time is 1s.

The 1st step, system initialization.Corresponding relation between the maximum amount of data C that calculating channel can transmit and the estimated value γ of each channel signal to noise ratio, the occupied bandwidth B of system and the cycle of operation length 10ms, promptly

C＝0.01×B×log(1+γ)

And following table form storage

The corresponding relation of table 1 signal to noise ratio and channel capacity

γ1	γ2	γ3	γ4	γ5	γ6	γ7	γ8	γ9	γ10	γ11	γ12	γ13	γ14	γ15	γ16
																C1	C2	C3	C4	C5	C6	C7	C8	C9	C10	C11	C12	C13	C14	C15	C16

The 2nd step: at maximum latency 1s and the stand-by period and the system transmissions time delay relation of user data, choose its propagation delay time respective value of 2 calculating of 0.25s and 0.75s and be respectively 0.2231 and 0.6065, according to (0.25,0.2231) and (0.75,0.6065) 2 points, the relation between calculated data stand-by period and the system operation cost:

P_wait(t)＝0.7668×t+0.0314

In the 3rd step, from table 1, search and channel status estimated value γ _iThe maximum amount of data C that corresponding channel can transmit _i(t), C _i(t) the wait data volume S that provides with the waiting list monitoring device _i(t) smaller value between is exactly can data quantity transmitted th between next one cycle of operation system and user _i(t);

The 4th step, data quantity transmitted th _i(t) the system operation cost P_wait that produces with the stand-by period _i(t) product is exactly user's dispatching priority PRI _i(t) be PRI _i(t)=th _i(t) P_wait _i(t);

In the 5th step, from m wait user, select PRI _i(t) Zui Da user provides service in the next cycle of operation, finishes once scheduling;

Repeated for the 2nd to the 5th step in the next scheduling process.

In each scheduling process, mobile communication system all is to have the user of high dispatching priority to transmit data.User's dispatching priority be by each user since user data wait for system operation cost that time delay produces and next cycle of operation system and the user between can data quantity transmitted product determine.

Claims (1)

1, a kind of dispatching method based on priority is characterized in that the implementation procedure of this method comprises following step:

The 1st step: the estimated value γ of the channel signal to noise ratio that bandwidth B that takies according to mobile communication system and channel estimating apparatus estimate, calculate each corresponding channel of different numerical value channel signal to noise ratios with each can transmit in each cycle of operation length maximum amount of data and preserve according to regular 1C=τ Blog (1+ γ) with the parameter list form, in rule 1, τ is that the length of each cycle of operation can be slot length or transmission frame length, C is the mobile communication system maximum amount of data that channel can transmit in cycle of operation length, B is system's occupied bandwidth, and γ is the estimated value of channel signal to noise ratio;

The 2nd step: according to the rule of relation between the system operation cost P_wait (t) that characterizes user data stand-by period and generation $2P\_\mathrm{wait}\left(t\right)=\frac{2\·(P_2-P_1)}{D}\×t+\frac{3\·P_1-P_2}{2}$ Calculate each user because the system operation cost P_wait that produces in the user data stand-by period t _t(t), in rule 2, D is that the maximum latency of user data is t≤D, P ₁And P ₂For user data etc. by the time the system operation cost that D/4 and 3D/4 produced during the time;

The 3rd step: according to the estimated value γ of each user's channel signal to noise ratio _iFrom the form of the 1st step preservation, search the maximum amount of data C that corresponding channel can transmit _i(t), according to regular 3th _i(t)=min{C _i(t) i, S _i(t) }, the channel maximum amount of data C that can transmit _i(t) wait for data volume S with the user _i(t) smaller value is exactly can data quantity transmitted th between next one cycle of operation system and user _i(t);

The 4th step is according to regular 4 PRI _i(t)=th _i(t) P_wait _i(t) calculate each Subscriber Queue dispatching priority, in rule 4, PRI _i(t) be user's dispatching priority, P_wait _i(t) be that the 2nd step drew because user data is waited for the system operation cost that time delay produces, th _i(t) be obtained in the 3rd step next cycle of operation system and the user between can data quantity transmitted;

In the 5th step, in the next cycle of operation, communication system is PRI _i(t) the highest user is transmitted data, finishes scheduling process one time;

Each dispatching method is to repeat the above the 2nd to the 5th to go on foot in each cycle of operation.

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