CN103561427B - A kind of base station power control method of lte-a system multi-cell radio network - Google Patents

Abstract

The invention discloses the base station power control method of a kind of LTE A system multi-cell radio network, the CQI information that reports of UE in load and community in eNodeB periodically detects community in system, when load state meets power control threshold value, i.e. start virtual power and control overloaded cells load is shifted to Di Zai community；If community not existing load imbalance problem or load imbalance having been resolved, then judge Cell Edge User ratio by CQI, if this ratio is more than threshold value, then starts the power control scheme of multi-point cooperative transmission, improve Cell Edge User QoS；If community not existing load imbalance problem and there is not edge customer QoS less than threshold value situation, or the problems referred to above having been resolved, then the method raising cell energies utilization rate adjusted by actual power.The present invention controls to solve the problems such as load imbalance under multiple cell scene, cell edge QoS and capacity usage ratio in a flow process by actual or virtual power, it is to avoid separately carry out the imperfect problem of system control.

Description

A kind of base station power control method of lte-a system multi-cell radio network

Technical field

The present invention relates to the base station power control method of a kind of lte-a system multi-cell radio network, in order to solve Certainly under multiple cell scene, load imbalance, cell edge quality of service ensure the problem such as (QoS) and power utilization, Belong to network communication technology field.

Background technology

LTE-A is that 3GPP organizes newest standards chemical conversion fruit, and it greatly improves wireless communication transmissions speed. But also will be faced with many significant challenge simultaneously.Load balancing, the raising of edge customer QoS and raising energy Amount utilization rate is to need three major issues of solution badly.

General, when load imbalance, lte-a system reaches load transfer by adjusting handoff parameter； When Cell Edge User is too much, system reaches to improve Cell Edge User communication by CoMP technology； When loading relatively low, base station power can be reduced and be even switched off base station to reach to improve capacity usage ratio.

The problems referred to above are generally separately solved by prior art, cause algorithm the most complicated.For this reason, it may be necessary to a kind of letter Single harmonized programme solves above-mentioned challenge.

Summary of the invention

Goal of the invention: for problems of the prior art with not enough, the present invention provides a kind of LTE-A system The base station power control method of system multi-cell radio network, it, for realizing load balancing simply, improves limit, community Edge QoS and raising cell energies efficiency describe a framework.Ask owing to improving load imbalance in community The priority of topic ensures higher than improving cell edge QoS, improves the priority of cell edge QoS higher than increasing Cell energies utilization rate.Technical scheme is as follows.

Technical scheme: the base station power control method of a kind of lte-a system multi-cell radio network, in judgement On the basis of Cheng Gong, successively community is used virtual power control, coordinated multipoint transmission (CoMP) and merit Rate controls.If cell load is uneven, Ze Dui community carries out the cell breathing controlled based on virtual power；If it is little Area edge user's ratio is more than threshold value, i.e. explanation Cell Edge User is too much, and Ze Dui community carries out multipoint cooperative Transmission is to improve edge customer traffic rate；If cell load is less than threshold value, Ze Dui community uses power to control To improve cell energies utilization rate.Lte-a system will circulate whole flow process in N number of TTI.

Specifically comprise the following steps that

Step one: lte-a system periodically detects community every the TTI time period within N × TTI time I (i=1,2,3 ...) loadsAnd the Signal to Interference plus Noise Ratio that in cell i, UE j reports T=t₀+ TTI, t₀+ 2 TTI ..., t₀+ N TTI, wherein, t₀At the end of upper N × TTI cycle Between point；The load statistics meansigma methods of cell i is calculated according to rule [1]And calculate according to rule [2] The Signal to Interference plus Noise Ratio average of UE j in cell iAnd perform step 2；

Step 2: if current area i loads load_iMore than threshold value L, the Target cell choosing of rule-based [3] Determine rule to choose suitable community and divert the aim community as load, and to current area and Target cell according to base Carry out load balancing in rule [5] and [6] of the load balancing of virtual emission power, terminate.If current area i Load load_iLess than threshold value L, then perform step 3；

Step 3: judge current area i inward flange user proportion r, if r is more than threshold value R, then holds Row step 4；If it is not, then perform step 5；

Step 4: judge UE type according to rule [8], current area i and its neighbor cell are carried out power Control, for using multi-point cooperative transmission (CoMP) to combine the transmission plans such as transmission, combined dispatching and velocity of wave molding Ready.If UE belongs to the user of edge type A, then the cooperation cell number of UE is 2；If UE belongs to In the user of edge type B, then the cooperation cell number of UE is 3；

Step 5: if the idle load of i neighbor cell can remain off after cell i the former logical of UE in cell i Letter speed, then perform step 6；If it is not, then perform step 7；

Step 6: if cell i load is less than or equal to the load of its adjacent arbitrary community, then according to rule [9] whether [10] [11] can close cell i.The most then close cell i, terminate；If it is not, then by current area It is revised as the community j that load adjacent for i is minimum, and new current area j is used above-mentioned steps five；

Step 7: according to the actual emission power of rule [14] amendment cell i to P_A' so that P_A' be able to maintain that User in cell i keeps original traffic rate.Assume P_A" it is less than P_A' arbitrarily launch power, then P_A″ The original traffic rate of user that all will reduce in cell i.

Described step one, to step 7, repeats according to cycle M × N × TTI；Wherein, TTI represents LTE Transmission Time Interval in system, usually 1ms.

Further, in described step one, cell load weighted statistical mean value computation rule-based [1]:

Wherein,For cell i t load, k represents cycle (referring to N × TTI) number.

Further, in described step one, the SINR mean value computation of UE is rule-based [2]:

Wherein,The size of the SINR value calculated for the CQI that reports based on user's t, K represents cycle (referring to N × TTI) number.

Further, in described step 2, load diverts the aim the selection rule-based [3] of community:

Wherein, T_cellRepresent Target cell numbering, load_iRepresent the load of present overload community, load_ITable Show the load of cell i neighbor cell, P_iThe reception power of the cell i that expression UE detects, P_IExamine for UE The j community measured accept power, w₁And w₂For weight coefficient, generally take 1.Community will select T_cell? Big neighbor cell diverts the aim community as load.

Further, in described step 2, cell i load calculates rule-based [4]:

Wherein,PRB quantity used by user j any in cell i.For in cell i The PRB total amount of all CUs, N_cellPRB quantity for community.

Further, in described step 2, the virtual emission merit of t+1 moment current area i and Target cell I Rate is revised rule-based [5] [6] respectively:

Pⁱ _V(t+1)=P^I _V(t)+P^I _A(t)-Pⁱ _A(t)+Δ_iI, rule [5]

Wherein, Pⁱ _V(t+1) it is the cell i virtual emission power in the t+1 moment, P^I _VT () is that community I is in t Virtual emission power, Pⁱ _AT () is cell i t actual emission power, P^I _AT () is that I community t is actual Launch power, Δ_iIFor cell i and the correction value of cell i virtual emission power,WithPoint The actual power from cell i not received for t UE and virtual power,With It is respectively the actual power from community I and virtual power that t UE receives.

Further, in described step 3, the calculating of Cell Edge User ratio is rule-based [7]:

Wherein, N_belowRefer to the traffic rate quantity less than the UE of threshold value V in cell i, N_sumIt is UE quantity total in referring to cell i.

Further, in described step 4, the judgement of edge type belonging to user is rule-based [8]:

Wherein, P_iRepresent the signal intensity from cell i that user receives, P_jRepresent that user receives next From the signal intensity of community j, T_edgeFor predetermined threshold value.

Further, in described step 6, after whether the idle load of i neighbor cell can maintain cell i to close The former traffic rate of UE rule-based [9] [10] [11] in cell i:

Wherein,Represent the idle load of the neighbor cell j of i, N_mRepresent that UE j is made before the handover PRB quantity,Represent that the SINR statistics before switching occurs of the UE j in cell i is flat Average,Representing the SINR value after switching occurs of the UE j in cell i, S represents switching The signal intensity that front UE receives, S' represents the signal intensity of target handover cell.S and S' can pass through UE Report acquisition,Can rule-based [2] obtain.

Further, in described step 7, P_A' value rule-based [14]:

Wherein, P_AT () is the primary power of penetrating of cell i, ρ is former cell i load,Former for cell i The meansigma methods of SINR in UE,Can be calculated by rule [11].

Beneficial effect: compared with prior art, the lte-a system multi-cell radio network that the present invention provides Base station power control method, solves load imbalance under multiple cell scene, cell edge QoS and energy The problems such as utilization rate, it is to avoid separately carry out the imperfect problem of system control, improve systematic function, reduce The complexity of the problem of solution.

Accompanying drawing explanation

Fig. 1 is the network structure of the embodiment of the present invention；

Fig. 2 is the flow chart of the embodiment of the present invention.

Detailed description of the invention

Below in conjunction with specific embodiment, it is further elucidated with the present invention, it should be understood that these embodiments are merely to illustrate this Invention rather than restriction the scope of the present invention, after having read the present invention, those skilled in the art are to this The amendment of the bright various equivalent form of values all falls within the application claims limited range.

As in figure 2 it is shown, for the base station power control method of lte-a system multi-cell radio network,

(1) SINR information that system reports at N number of TTI periodically each cell load of detection and each UE, Calculate and compare the SINR average statistical of each UE in each cell load weighted statistical average and each community, and Perform step (2)；

Wherein, the calculating rule-based [1] of each cell load weighted statistical average:

The calculating of the SINR average of each UE rule-based [2] in community:

(1) if current area i loads load_iMore than threshold value L, select rule based on Target cell and choose suitably Community is as Target cell, and current area and Target cell are used load balancing based on virtual emission power Scheme.If current area i loads load_iLess than threshold value L, then perform step (3)；

Wherein, UE diverts the aim the selection rule-based [3] of community:

Cell i load calculates rule-based [4]:

The virtual emission power of t+1 moment current area i and Target cell I is revised rule-based [5] [6] respectively:

Pⁱ _V(t+1)=P^I _V(t)+P^I _A(t)-Pⁱ _A(t)+Δ_iI, rule [5]

(2) current area i judges ratio r of Cell Edge User by the SINR information that UE feeds back.If r Higher than threshold value R, then current area i and its neighbor cell are taked CoMP technology, and performs step (4). If r is less than threshold value R, and performs step (5)；

Wherein, the calculating of Cell Edge User ratio rule-based [7]:

(3) UE type is judged.If UE belongs to A type edge customer, then the cooperation cell number of UE is 2；If UE belongs to Type B edge customer, then the cooperation cell number of UE is 3；

Wherein, the judgement of edge type belonging to user rule-based [8]:

(5) if the idle load of i neighbor cell can remain off after cell i the former traffic rate of UE in cell i, Then perform step (6)；If it is not, then perform step (7)；

Wherein, the former traffic rate of UE in cell i after whether the idle load of i neighbor cell can maintain cell i to close Rule-based [8] [9] [10]:

(6) if cell i load is less than or equal to the load of its adjacent arbitrary community, then cell i is closed；If it is not, Then current area is revised as the community j that load adjacent for i is minimum, and new current area j is used above-mentioned mistake Journey；

(7) actual emission power of amendment cell i is to P_A' so that P_A' the user that is able to maintain that in cell i keeps Original traffic rate.Assume P_A" it is less than P_A' arbitrarily launch power, then P_A" all will reduce in cell i The original traffic rate of user.

Wherein, P_A' value rule-based [14]:

Described step (1)～(7) repeat according to several TTI of cycle；Wherein, TTI represents transmission Time interval, for 1ms.

Embodiment one

Structure one structure TDD-LTE-A network as shown in Figure 2, one has 19 communities, each community Using omnidirectional antenna, the frequency duplex factor as one of minizone is 1, and in addition to edge cell, each community has six Neighbor cell.Base station power is limited to P_max=30w.The cycle that power controls to run every time is 100 × 10 TTI。

Following table provides the real system parameter list of TDD-LTE-A network:

(1) the average load situation of system-computed 100 × 10 GeTTINei community 1:

${\mathrm{load}}_1^{\mathrm{avg}}=\frac{\underset{t=0}{\overset{99\×(10\×1\mathrm{ms})}{\∑}}{\mathrm{load}}_1^{\mathrm{cur}}(t+t_0)}{100}$

The average statistical of the SINR in 100 × 10 TTI of the UE j in calculating community 1:

${\mathrm{SINR}}_{1,j}^{avg}\left(t\right)=\frac{\underset{t=0}{\overset{99\×(10\×1ms)}{\Σ}}{\mathrm{SINR}}_{1,j}^{cur}(t+t_0)}{N}$

(2) ifMore than threshold value L=0.95, then start virtual power and control.If it is not, then perform Step (3) continues to judge.

(3) in calculating community 1, SINR is less than ratio r total for UE shared by the UE of threshold value S=0.5dB Whether more than threshold value R=20%.The most then start CoMP to improve Cell Edge User traffic rate.

(4) edge type belonging to edge UE is judged.If UE belongs to A type edge customer, then utilize 2 Individual community carries out multipoint cooperative communication to UE；If UE belongs to Type B edge customer, then utilize 3 communities pair UE carries out multipoint cooperative communication.

(5) judge in the case of community 1 is closed, the neighbor cell (community 2,3,4,5,6 and 7) of community 1 Idle load can maintain the traffic rate of each UE in former community 1.If so, step (6) is performed；If it is not, Then perform step (7).

(6) judge whether that the load of community 1 is less than any one community in its neighbor cell.The most then Close community 1.If it is not, then Target cell is transferred in its neighbor cell the community loading minimum, and little to this District performs step (5).Wherein, Fig. 2 is referred to for the calculating of logarithm with 2 as the end in rule [10].

(7) acquiescence reducing community 1 launches power P_A=30w to P_A' so that each UE communication in community 1 Speed is unaffected.

Whole system every time will in 100 × 10 TTI repeat the above steps.

Embodiment two

As shown in figure (3), construct a structure FDD-LTE-A network, comprise 19 communities equally, each Community uses omnidirectional antenna, and the frequency duplex factor as one of minizone is 1, and in addition to edge cell, each community has Six neighbor cells.Base station power is limited to P_max=30w.The cycle that power controls to run every time is 100 × 10 Individual TTI.

(1) the average load situation of system-computed 100 GeTTINei community 1:

${\mathrm{load}}_1^{avg}=\frac{\underset{t=0}{\overset{99\×(10\×1ms)}{\Σ}}{\mathrm{load}}_1^{cur}(t+t_0)}{100}$

The average statistical of the SINR in 100 × 10 TTI of the UE j in calculating community 1:

${\mathrm{SINR}}_{1,j}^{avg}\left(t\right)=\frac{\underset{t=0}{\overset{99\×(10\×1ms)}{\Σ}}{\mathrm{SINR}}_{1,j}^{cur}(t+t_0)}{N}$

(2) ifMore than threshold value L=0.95, then start virtual power and control.If it is not, then perform step Suddenly (3) continue to judge.

(3) in calculating community 1, SINR is less than ratio r total for UE shared by the UE of threshold value S=0.5dB Whether more than threshold value R=20%.The most then start CoMP to improve Cell Edge User traffic rate.

(4) edge type belonging to edge UE is judged.If UE belongs to A type edge customer, then utilize 2 Individual community carries out multipoint cooperative communication to UE；If UE belongs to Type B edge customer, then utilize 3 communities pair UE carries out multipoint cooperative communication.

(5) judge in the case of community 1 is closed, the neighbor cell (community 2,3,4,5,6 and 7) of community 1 Idle load can maintain the traffic rate of each UE in former community 1.If so, step (6) is performed；If it is not, Then perform step (7).For rule [10] in 2 be end logarithm calculating refer to Fig. 2 equally.

(6) judge whether that the load of community 1 is less than any one community in its neighbor cell.The most then Close community 1.If it is not, then Target cell is transferred in its neighbor cell the community loading minimum, and little to this District performs step (5).

(7) acquiescence reducing community 1 launches power P_A=30w to P_A' so that each UE communication in community 1 Speed is unaffected.

Whole system every time will in 100 × 10 TTI repeat the above steps.

Claims (6)

1. the base station power control method of a lte-a system multi-cell radio network, it is characterised in that: net In network, each base station sets an actual emission power P_A(t) and virtual power P_V(t)；

Power control process specifically comprises the following steps that

Step one: lte-a system is at M × N × periodically examine every N × TTI time period in the TTI time Survey cell i (i=1,2,3 ...) loadAnd the Signal to Interference plus Noise Ratio that in cell i, UE j reportsT=t₀+ N × TTI, t₀+ 2 × N × TTI ..., t₀+ M × N × TTI, wherein, t₀For upper The end time point in one M × N × TTI cycle；Calculate the load weighted statistical average of cell i simultaneouslyAnd according to the Signal to Interference plus Noise Ratio average of UE j in rule [2] calculating cell iAnd hold Row step 2

Step 2: if current area i loads load_iMore than threshold value L, choose suitable community and turn as load Move Target cell, and current area and Target cell are carried out load balancing based on virtual emission power, terminate； If current area i loads load_iLess than threshold value L, then perform step 3；

Load diverts the aim the selection rule-based [3] of community:

Wherein, T_cellRepresent Target cell numbering, load_iRepresent the load of current area i, load_IRepresent The load of cell i neighbor cell I, P_iThe reception power of the cell i that expression UE detects, P_IExamine for UE The reception power of the community I measured, w₁And w₂For weight coefficient, generally take 1；Community will select T_cell? Big neighbor cell diverts the aim community as load；

In described step 2, the virtual emission power of t+1 moment current area i and Target cell I is revised respectively Rule-based [5] [6]:

Pⁱ _V(t+1)=P^I _V(t)+P^I _A(t)-Pⁱ _A(t)+Δ_iI, rule [5]

Wherein, Pⁱ _V(t+1) it is the cell i virtual emission power in the t+1 moment, P^I _VT () is that community I is in t Virtual emission power, Pⁱ _AT () is cell i t actual emission power, P^I _AT () is that I community t is actual Launch power, Δ_iIFor cell i and the correction value of community I virtual emission power,WithPoint The actual power from cell i not received for t UE and virtual power,With It is respectively the actual power from community I and virtual power that t UE receives；

Step 3: judge current area i inward flange user proportion r is if r is more than threshold value R, the most right CoMP technology is taked in current area i and its neighbor cell, and performs step 4；If it is not, then perform step Five；

The calculating of Cell Edge User ratio is rule-based [7]:

Wherein, N_belowRefer to the traffic rate quantity less than the UE of threshold value V in cell i, N_sumIt is UE quantity total in referring to cell i；

Step 4: judge UE type, carries out power control to current area i and its neighbor cell；If UE Belong to A type edge customer, then the cooperation cell number of UE is 2；If UE belongs to Type B edge customer, then The cooperation cell number of UE is 3；A type and Type B edge customer are defined as:

Wherein, P_iRepresent the signal intensity from cell i that user receives, P_jRepresent that user receives next From the signal intensity of community j, T_edgeFor predetermined threshold value, terminate；

Step 5: if the idle load of cell i neighbor cell can remain off after cell i UE in cell i Former traffic rate, then perform step 6；If it is not, then perform step 7；

Step 6: if cell i load is less than or equal to the load of its adjacent arbitrary community, then judge whether to close Close cell i；The most then close cell i, terminate；If it is not, then current area to be revised as the adjacent load of i Minimum community j, and new current area j is used the process of step 5；

Step 7: the actual emission power of amendment cell i to P '_ASo that P '_AThe use being able to maintain that in cell i Family keeps original traffic rate；Assume P "_AFor less than P '_AArbitrarily launch power, then P "_AWill be unable to maintain The original traffic rate of user in cell i；

Repeat above-mentioned steps one to step 7；Wherein, Transmission Time Interval during TTI represents LTE system.

2. the base station power control method of lte-a system multi-cell radio network as claimed in claim 1, It is characterized in that: in described step one, cell load weighted statistical mean value computation rule-based [1]:

Wherein,For cell i t load, k represents periodicity, and m (t) represents that load adds Weight coefficient, m (t) generally can be set to 1.

3. the base station power control method of lte-a system multi-cell radio network as claimed in claim 1, It is characterized in that: in described step one, the SINR mean value computation of UE is rule-based [2]:

Wherein,The size of the SINR value for reporting in t based on UE j arbitrary in cell i, K represents periodicity.

4. the base station power control method of lte-a system multi-cell radio network as claimed in claim 1, It is characterized in that: in described step 2, cell i load calculates rule-based [4]:

Wherein,PRB quantity used by user j any in cell i,For in cell i The PRB total amount of all CUs, N_cellPRB quantity for community.

5. the base station power control method of lte-a system multi-cell radio network as claimed in claim 3, It is characterized in that: in described step 6, whether the idle load of i neighbor cell is little after cell i can be maintained to close The former traffic rate of UE rule-based [9] [10] [11] in district i:

Wherein,Represent the idle load of the neighbor cell j of i, N_jRepresent that UE j is made before the handover PRB quantity, N_cellRepresent the PRB quantity that every community is total,Represent in cell i UE j SINR assembly average before switching occurs,Represent that the UE j in cell i is cutting Changing the SINR value after life, S represents the signal intensity that the front UE of switching receives, and S' represents that target switching is little The signal intensity in district, S and S' can report acquisition by UE,Can rule-based [2] obtain.

6. the base station power control method of lte-a system multi-cell radio network as claimed in claim 5, It is characterized in that: in described step 7, P '_AValue rule-based [14]:

Wherein, P_AT () is the primary power of penetrating of cell i, ρ is former cell i load,For little before switching The meansigma methods of the SINR of all UE in district i,Can be calculated by rule [11].