Invention content
For the disadvantages described above or Improvement requirement of the prior art, the present invention provides a kind of LTE based on optimized throughput
Downlink scheduling method, it is intended that solving existing LTE downlink schedulings method does not deeply consider distributed physics
Resource block interactional factor during actual transmissions data, and user in Physical Resource Block assigning process may be caused real
The technical issues of border volume of transmitted data is reduced.
To achieve the above object, according to one aspect of the present invention, a kind of LTE downlinks based on optimized throughput are provided
Link scheduling method, includes the following steps:
(1) the physical resource block number that can be called in single Transmission Time Interval is worth to according to the bandwidth of downlink
Mesh, and determination will carry out the number of users and resource allocation algorithm of Physical Resource Block distribution;
(2) all users of Physical Resource Block distribution are carried out according to the resource allocation algorithm determination determined in step (1)
Metric on all Physical Resource Block called;
(3) all users that carry out Physical Resource Block distribution obtained according to step (2) are in all physics called
All Physical Resource Block called are distributed to user by the metric on resource block.
Preferably, when the bandwidth value of LTE downlinks is respectively 1.4,3,5,10,15,20MHz when, corresponding physics
Resource block quantity is 6,15,25,50,75,100 respectively.
Preferably, resource allocation algorithm can be equitable proportion PF algorithms, maximum carry than dry Max-CQI algorithms, most greatly
Temporary prolong preferential M-LWDF algorithms or index proportion justice EXP/PF algorithms.
Preferably, step (2) is specially:
First, calculate to carry out the Physical Resource Block that all users of Physical Resource Block distribution have obtained synthesis it is effective
The ratio of signal and interference noise, specific formula for calculation are as follows:
effvaluen=10log (- log (s))
Wherein s is intermediate variable, and n expressions will carry out the physical resource that each user of Physical Resource Block distribution has obtained
Block number mesh;sinrjValue indicates to carry out each user having on j-th of Physical Resource Block of acquisition of Physical Resource Block distribution
Imitate the ratio of signal and interference noise;effvaluenIndicate n that each user that carry out Physical Resource Block distribution is obtained
The ratio of synthesis useful signal and interference noise on Physical Resource Block;
Secondly, the Physical Resource Block number n that has been obtained according to each user of Physical Resource Block distribution to be carried out and
The synthesis useful signal for the Physical Resource Block that all users have obtained and the ratio effvalue of interference noisenTo obtain the use
The data transmission total amount for all n Physical Resource Block that family has obtained, passes through following function representation:
bittransn=GetBit (effvaluen,n)
Wherein bittransnIndicate the actual amount of data that all n Physical Resource Block that user has obtained can transmit;
GetBit indicates to obtain the function expression of transmission data;
Then, the data transmission total amount of user's all n+1 Physical Resource Block to be obtained is calculatedWith
The data transmission total amount bittrans of all n Physical Resource Block obtainednBetween difference, as the user in physical resource
The changing value data_change of the front and back actual data transfer total amount of block distribution, specific formula are as follows:
Data_change=bittransn+1-bittransn
Finally, according to the resource allocation algorithm determined in step (1) and obtained user before and after Physical Resource Block distribution
The changing value data_change determinations of actual data transfer total amount to carry out all users of Physical Resource Block distribution it is all can
Metric metric on the Physical Resource Block of calling.
Preferably, the calculating process of the function expression GetBit of transmission data is obtained specifically, first according to ratio
effvaluenThe CQI coding mode tables for inquiring LTE system, to determine Physical Resource Block by the modulation of use and coding mode, so
Corresponding data carrying amount is found in CQI coding mode tables according to determining modulation and coding mode afterwards, finally by data
Carrying amount is multiplied by the quantity of Physical Resource Block, to obtain the data transmission of all n Physical Resource Block that the user has obtained
Total amount.
Preferably, when resource allocation algorithm is maximum carries than stem algorithm, the calculation formula of metric is as follows:
Wherein i indicates to carry out the serial number of the user of Physical Resource Block distribution.
Preferably, when resource allocation algorithm is proportional fair algorithm, the calculation formula of metric is as follows:
WhereinIndicate average throughput of i-th of user before current transmission time interval.
Preferably, when resource allocation algorithm is maximum weighted time delay priority algorithm, the calculation formula of metric is as follows:
Wherein intermediate variable ωi=-log δi/τi, wherein δiIndicate that the end of a thread queuing delay of i-th of user is more than delay threshold
The maximum likelihood of value, τiIndicate the target maximum delay of i-th of user, di(t) it is then the end of a thread queuing delay of i-th of user.
Preferably, when resource allocation algorithm is index proportional fair algorithm, the calculation formula of metric is as follows:
Wherein be averaged the end of a thread queuing delaynRIndicate the real-time service of user
Quantity.
Preferably, step (3) specifically includes following sub-step:
(3-1) statistics in all users of Physical Resource Block distribution to be carried out has data to need all users transmitted,
And metric of all users of statistics on all Physical Resource Block is obtained according to the result of step (2);
(3-2) distributes to all of step (3-1) statistics for each Physical Resource Block, by the Physical Resource Block
User in user in the corresponding metric of the Physical Resource Block corresponding to maximum value.
In general, through the invention it is contemplated above technical scheme is compared with the prior art, can obtain down and show
Beneficial effect:
(1) since present invention employs steps (2) to obtain degree of all users on all Physical Resource Block called
Magnitude, so as to ensure that all Physical Resource Block can increase actual volume of transmitted data in the assignment procedure, so as to
The technical issues of user's actual data transfer amount is reduced in Physical Resource Block assigning process may be led to by solving existing method.
(2) since the present invention enables to all Physical Resource Block to increase actual volume of transmitted data in the assignment procedure,
So as to effectively improve the handling capacity of entire LTE system, and improve the packet loss of LTE system.
Specific implementation mode
In order to make the purpose , technical scheme and advantage of the present invention be clearer, with reference to the accompanying drawings and embodiments, right
The present invention is further elaborated.It should be appreciated that the specific embodiments described herein are merely illustrative of the present invention, and
It is not used in the restriction present invention.As long as in addition, technical characteristic involved in the various embodiments of the present invention described below
It does not constitute a conflict with each other and can be combined with each other.
As shown in Figure 1, the LTE downlink scheduling methods the present invention is based on optimized throughput include the following steps:
(1) physics that being worth to according to the bandwidth of downlink can call in single Transmission Time Interval (1 millisecond) provides
Source block number, and determination will carry out the number of users and resource allocation algorithm of Physical Resource Block distribution;
Specifically, for the bandwidth value of downlink be respectively 1.4,3,5,10,15, for 20MHz, corresponding object
It is 6,15,25,50,75,100 to manage resource block quantity.
The resource allocation algorithm used in this step can be that equitable proportion (Proportional fair, abbreviation PF) is calculated
Method, maximum load are more preferential than doing (Max channel quality indicator, Max-CQI) algorithm, maximum weighted time delay
(Modified Largest Weighted Delay First, abbreviation M-LWDF) algorithm or index proportion are fair
(Exponential proportional fair, abbreviation EXP/PF) algorithm.
(2) all users of Physical Resource Block distribution are carried out according to the resource allocation algorithm determination determined in step (1)
Metric on all Physical Resource Block called;
Specifically, this step calculates first will carry out the physics money that all users of Physical Resource Block distribution have obtained
The synthesis useful signal of source block and the ratio of interference noise, specific formula for calculation are as follows:
effvaluen=10log (- log (s))
Wherein s is intermediate variable, and n expressions will carry out the physical resource that each user of Physical Resource Block distribution has obtained
Block number mesh;sinrjValue indicates to carry out each user having on j-th of Physical Resource Block of acquisition of Physical Resource Block distribution
Imitate the ratio of signal and interference noise (j is natural number, and has j≤x, and wherein x indicates the sum for the Physical Resource Block that can be called);
effvaluenIndicate that the synthesis that carry out on the n Physical Resource Block that each user of Physical Resource Block distribution is obtained is effective
The ratio of signal and interference noise, unit dB.
Secondly, the Physical Resource Block number n that has been obtained according to each user of Physical Resource Block distribution to be carried out and
The synthesis useful signal for the Physical Resource Block that all users have obtained and the ratio effvalue of interference noisenTo obtain the use
The data transmission total amount for all n Physical Resource Block that family has obtained, passes through following function representation:
bittransn=GetBit (effvaluen,n)
Wherein bittransnIndicate the actual amount of data that all n Physical Resource Block that user has obtained can transmit;
GetBit indicates to obtain the function expression of transmission data, is according to ratio effvalue firstnInquire the channel of LTE system
Quality indicates (Channel quality indicator, abbreviation CQI) coding mode table, to determine that Physical Resource Block will use
Modulation and coding mode, corresponding number is then found in CQI coding mode tables according to determining modulation and coding mode
According to carrying amount (Bits Carried), data carrying amount is finally multiplied by the quantity of Physical Resource Block, it will be able to obtain the user
The data transmission total amount of all n Physical Resource Block obtained.
Then, the data transmission total amount of user's all n+1 Physical Resource Block to be obtained is calculatedWith
The data transmission total amount bittrans of all n Physical Resource Block obtainednBetween difference, as the user in physical resource
The changing value data_change of the front and back actual data transfer total amount of block distribution, specific formula are as follows:
Data_change=bittransn+1-bittransn
Finally, according to the resource allocation algorithm determined in step (1) and obtained user before and after Physical Resource Block distribution
The changing value data_change determinations of actual data transfer total amount to carry out all users of Physical Resource Block distribution it is all can
Metric metric on the Physical Resource Block of calling;
Wherein, for maximum is carried than stem algorithm, the calculation formula of metric is as follows:
Wherein i indicates to carry out the serial number of the user of Physical Resource Block distribution, and has i≤y, and wherein y expressions will carry out object
Manage the number of users of resource block distribution;
For proportional fair algorithm, the calculation formula of metric is as follows:
WhereinIndicate average throughput of i-th of user before current transmission time interval.
For maximum weighted time delay priority algorithm, the calculation formula of metric is as follows:
Wherein intermediate variable ωi=-log δi/τi, wherein δiIndicate that the end of a thread of i-th of user is lined up (Head-of-line
Blocking, abbreviation HOL) it is delayed more than the maximum likelihood of delay threshold, τiIndicate the target maximum delay of i-th of user, di
(t) it is then the end of a thread queuing delay of i-th of user.
For index proportion fair algorithm, the calculation formula of metric is as follows:
Wherein be averaged the end of a thread queuing delaynRIndicate the real-time service of user
Quantity, real-time service include video, audio etc..
If the Physical Resource Block that can be called has x, the number of users that carry out Physical Resource Block distribution is y, then exists
After this step terminates, the metric of obtained the 1st user on all y Physical Resource Block is (metric11,
metric12, metric13, metric1y), metric of the 2nd user on all y Physical Resource Block is (metric21,
metric22, metric23, metric2y) ..., metric of x-th of user on all y Physical Resource Block is
(metricx1, metricx2, metricx3, metricxy)。
(3) all users that carry out Physical Resource Block distribution obtained according to step (2) are in all physics called
All Physical Resource Block called are distributed to user by the metric on resource block.
This step specifically includes following sub-step:
(3-1) statistics in all users of Physical Resource Block distribution to be carried out has data to need all users transmitted,
And metric of all users of statistics on all Physical Resource Block is obtained according to the result of step (2);
(3-2) distributes to all of step (3-1) statistics for each Physical Resource Block, by the Physical Resource Block
User in user in the corresponding metric of the Physical Resource Block corresponding to maximum value;
For example, for the 2nd Physical Resource Block, it is corresponding with multiple metrics, respectively metric12,
metric22..., metricx2, this step is exactly to find in these values maximum one, such as metric52, then the knot of this step
2nd Physical Resource Block is exactly distributed to the 5th user by fruit.
Experimental result and analysis
Tables 1 and 2 is respectively average throughput of the user in Video service under 30km/h and 120km/h.From image
From the point of view of list data comparison, the handling capacity of video traffic of the present invention has a degree of promotion, with number of users
It is continuously increased, the average throughput that video traffic is obtained constantly is reducing, but total incrementss are still more considerable.
Video average throughput (kbps) under 1 30km/h of table
Video average throughput (kbps) under 2 120km/h of table
In the following table 3 and table 4 be respectively 30km/h and 120km/h under user the type of doing one's best (Best effort, letter
Claim Be) service in average throughput.For playing MT algorithms, handling capacity of the invention has growth.And to MT algorithms
For, since Physical Resource Block is inherently distributed to the user with optimum channel by the algorithm, so in contrast, system
The promotion degree of handling capacity is minimum, or even since part physical resource block turns to be allocated to Video service, so Be types gulp down
The amount of spitting has a little decline, but the total handling capacity of the present invention is still in promotion state.
The handling capacity (kbps) that Be is serviced under 3 30km/h of table
The handling capacity (kbps) that Be is serviced under 4 120km/h of table
As it will be easily appreciated by one skilled in the art that the foregoing is merely illustrative of the preferred embodiments of the present invention, not to
The limitation present invention, all within the spirits and principles of the present invention made by all any modification, equivalent and improvement etc., should all include
Within protection scope of the present invention.