CN101267237A - A smart antenna downlink transmission power overload control method - Google Patents

Abstract

The present invention relates to a method for controlling an intelligent antenna descending transmitting power overload. The method comprises the following procedures: based on a descending wave beam forming authority vector w<(k)>=(w<(k, m)>), an antenna correcting authority value vector WAC=(w(m)AC), a power control factor rho PC<(k)> and a power compensating factor alpha<(k)> of each antenna user, calculating a descending composite weight vector omega<(k)>=(omega<(k, m)>) of each antenna user an each user descending composite weight modular multiplication summation (formula I) corresponding to the antenna itself, wherein (formula II); and if the modular multiplication summation (formula III) is larger than 1, then modifying the user descending composite weight omega<(k, m)> of the corresponding antenna to lead to that the modular multiplication summation (formula IV) is smaller or equal to 1. The method can execute overload control to a random single antenna with transmitting power overload in the intelligent antenna, lead to that the transmitting power of each antenna satisfies the designing request. The normal operation of the system equipment is guaranteed and the capacity loss of the system is reduced to the greatest extent.

Description

A kind of smart antenna downlink transmission power overload control method

Technical field

The present invention relates to mobile communcations system, be specifically related to a kind of smart antenna downlink transmission power overload control method.

Background technology

Smart antenna is made of aerial array, utilize transmission of wireless signals spatial character and Digital Signal Processing, can realize shape-endowing weight value vector and down beam shaping, thereby reach the purpose that reduces interference, increase capacity, expansion covering, improves communication quality, reduction transmitting power and raising wireless data transmission rate.

Under certain user moving speed condition, for the S-CDMA cdma communication system that adopts the TDD mode, its upper and lower channel satisfies symmetrical requirement, if adopt smart antenna, the shape-endowing weight value vector that can realize each user then according to the up received signal or the channel estimating of aerial array correspondence, and then finish down beam shaping, solve problems such as anti-multipath interference and anti-multiple access interference preferably.

In the antenna system, the down transmitting power of antenna is subjected to the direct influence of all multi-parameters, comprise descending beam shape-endowing weight value vector, antenna correction weighted vector, power control factor and the power back-off factor etc., and there is the upper limit undoubtedly in the transmitting power of each passage.Owing to have certain independence between the above-mentioned parameter; interact between a plurality of parameters, therefore under specific situation, phenomenon may appear transshipping in the transmitting power of some antenna channels; if do not adopt safeguard measure, then must cause system link performance and network performance obviously to descend.

Chinese invention patent " a kind of method of base station down transmitting power control ", publication number CN1812284, a kind of method of base station down transmitting power control is disclosed, promptly at the fixed time at interval in, according to N power per liter and M predetermined alternating sequence that falls power the down transmitting power of base station is controlled, can be under the desynchronizing state at the up-link wireless link of base station side, avoid the unusual power control of base station down transmitting power, make the down transmitting power of base station keep stable.This method can be controlled total down transmitting power control of base station side, but has only considered the influence of power control factor parameter, does not distinguish each antenna channels, can't judge promptly whether single-antenna transmission power transships.

Summary of the invention

The technical issues that need to address of the present invention provide a kind of smart antenna downlink transmission power overload control method, can distinguish each antenna channels, and each antenna transmitting power in the smart antenna is transshipped control.

Above-mentioned technical problem of the present invention solves like this, and a kind of smart antenna downlink transmission power overload control method is provided, and may further comprise the steps:

1.1) overload identification: based on each each user's of antenna descending beam shape-endowing weight value vector w ^(k)={ w ^{(k, m)}, antenna proofreaies and correct weighted vector $w_{\mathrm{AC}}=\left\{w_{\mathrm{AC}}^{\left(m\right)}\right\}$ , power control factor ρ _PC ^(k)And power back-off factor-alpha ^(k), calculate each user's downlink composite weights ω of each antenna ^{(k, m)}And each user's downlink composite weights mould quadratic sum of correspondence self antenna

Wherein ${\mathrm{\&omega;}}^{(k,m)}={\mathrm{\&alpha;}}^{\left(k\right)}\&CenterDot;w_{\mathrm{AC}}^{\left(m\right)}\&CenterDot;w^{(k,m)}\&CenterDot;{\mathrm{\&rho;}}_{\mathrm{PC}}^{\left(k\right)},$ K refers to k user, is total to K user, and m refers to m antenna;

1.2) overload control: if described mould quadratic sum

Greater than 1, then revise user's downlink composite weights ω of respective antenna ^{(k, m)}Make described mould quadratic sum

Be less than or equal to 1.

According to control method provided by the invention, described step 1.2) revising in is each the user's downlink composite weights ω that reduces respective antenna in proportion ^{(k, m)}

According to control method provided by the invention, described ratio is meant user's downlink composite weights mould square | ω ^{(k, m)}| ²With each user's downlink composite weights mould quadratic sum

Proportionality coefficient.

According to control method provided by the invention, described step 1.2) revising in is to described user's downlink composite weights ω ^{(k, m)}Or revised user's downlink composite weights ω ^{(k, m)}Sort from big to small by the mould square value, reduce its mould square until described mould quadratic sum to wherein coming the foremost with fixed size at every turn

Be less than or equal to 1.

According to control method provided by the invention, described to come top be one of maximum or maximum, that is: maximum can be same big one or more, only appoints when a plurality of to get wherein any and come the foremost and get final product.

According to control method provided by the invention, described power back-off factor-alpha ^(k)Be expressed as ${\mathrm{\&alpha;}}^{\left(k\right)}=\frac{\sqrt{M}\&CenterDot;\sqrt{\underset{w_m^{\left(k\right)}}{\max }\left[{\left|w^{(k,m)}\right|}^2\right]}}{\sqrt{\underset{m=0}{\overset{M-1}{\mathrm{\&Sigma;}}}}{\left|w^{(k,m)}\right|}^2}\&CenterDot;{\mathrm{\&eta;}}^{\left(k\right)}$ , η wherein ^(k)It is the gain compensation factor between k user's different beams forms.

According to control method provided by the invention, η ^(k)General range be $\frac{M}{4}\&le;{\mathrm{\&eta;}}^{\left(k\right)}\&le;4\&CenterDot;M.$

According to control method provided by the invention, described wave beam includes, but are not limited to business beam and broadcast beam.

According to control method provided by the invention, this control method is applied in the synchronous CDMA communications system that adopts TDD, described descending beam shape-endowing weight value vector w ^(k)={ w ^{(k, m)}Obtain according to measuring corresponding up received signal or channel estimating.

According to control method provided by the invention, the synchronous CDMA communications system of described employing TDD can be the TD-SCDMA system of 1.28Mcps or 3.84Mcps.

According to control method provided by the invention, this control method is applied in the synchronous CDMA communications system that adopts FDD, described descending beam shape-endowing weight value vector w ^(k)={ w ^{(k, m)}Can reach the angle according to ripple and estimate to obtain.

Smart antenna downlink transmission power overload control method provided by the invention, based on the descending beam shape-endowing weight value vector, antenna is proofreaied and correct weighted vector, the power control factor and the power back-off factor, calculate each user's downlink composite weights of each antenna, further calculate and judge whether each antenna transmitting power transships and the antenna correction respective user downlink composite weights of transmission power overload, thereby can transship control to any single antenna of transmission power overload in the smart antenna, the transmitting power of each antenna is met design requirement, safeguards system equipment operate as normal, and reduce the performance loss of system as far as possible.

Description of drawings

Further the present invention is described in detail below in conjunction with the drawings and specific embodiments.

Fig. 1 is the schematic flow sheet of smart antenna transmission power overload control method correspondence of the present invention.

Fig. 2 is the schematic flow sheet of the implementation one of downlink composite weights correction among Fig. 1.

Fig. 3 is the schematic flow sheet of the implementation two of downlink composite weights correction among Fig. 1.

Embodiment

As shown in Figure 1, smart antenna downlink transmission power overload guard method of the present invention specifically may further comprise the steps:

110) proofread and correct weighted vector, power control factor and the power back-off factor based on descending beam shape-endowing weight value vector, antenna, calculate downlink transmission power overload flags parameters and each corresponding user's downlink composite weights of each antenna.

K user's descending beam shape-endowing weight value vector is w ^(k)={ w ^{(k, m)}| _{M=0,1 ..., M-1}K user's power control factor is ρ _PC ^(k)Antenna is proofreaied and correct weighted vector $w_{\mathrm{AC}}={\left\{w_{\mathrm{AC}}^{\left(m\right)}\right\}|}_{m=\mathrm{0,1},\&CenterDot;\&CenterDot;\&CenterDot;,M-1};$ K user's the power back-off factor is α ^(k)Number of users is K, and antenna number is M.

Calculate the downlink transmission power overload flags parameters of m antenna correspondence, be expressed as:

$F^{\left(m\right)}=\underset{k=0}{\overset{K-1}{\mathrm{\&Sigma;}}}{|{\mathrm{\&alpha;}}^{\left(k\right)}\&CenterDot;w_{\mathrm{AC}}^{\left(m\right)}\&CenterDot;w^{(k,m)}\&CenterDot;{\mathrm{\&rho;}}_{\mathrm{PC}}^{\left(k\right)}|}^2$

$=\underset{k=0}{\overset{K-1}{\mathrm{\&Sigma;}}}{\left|{\mathrm{\&omega;}}^{(k,m)}\right|}^2,m=\mathrm{0,1},\&CenterDot;\&CenterDot;\&CenterDot;,M-1$

M antenna, a k user's downlink composite weight table is shown:

${\mathrm{\&omega;}}^{(k,m)}={\mathrm{\&alpha;}}^{\left(k\right)}\&CenterDot;w_{\mathrm{AC}}^{\left(m\right)}\&CenterDot;w^{(k,m)}\&CenterDot;{\mathrm{\&rho;}}_{\mathrm{PC}}^{\left(k\right)}$

K user's power back-off factor representation is:

${\mathrm{\&alpha;}}^{\left(k\right)}=\frac{\sqrt{M}\&CenterDot;\sqrt{\underset{w_m^{\left(k\right)}}{\max }\left[{\left|w^{(k,m)}\right|}^2\right]}}{\sqrt{\underset{m=0}{\overset{M-1}{\mathrm{\&Sigma;}}}}{\left|w^{(k,m)}\right|}^2}\&CenterDot;{\mathrm{\&eta;}}^{\left(k\right)}$

η in the formula ^(k)Represent k the gain compensation factor between the formation of user's different beams, as the gain compensation factor between business beam and the broadcast beam, usually $\frac{M}{4}\&le;{\mathrm{\&eta;}}^{\left(k\right)}\&le;4\&CenterDot;M.$

Does 120) down transmitting power of judging a certain antenna transship? if carry out step 130); Otherwise, go to step 140), that is:

If satisfy F ^(m)＞1, show the transmission power overload of m antenna, then carry out step 130), realize the overload protection measure.

If satisfy F ^(m)≤ 1, show that the transmitting power of m antenna is not transshipped, then m antenna, all users' downlink composite weights all remain unchanged, and go to step 140).

130) for the transmission power overload antenna, realize the overload protection measure, revise corresponding downlink composite weights.

Do 140) whether all antennas all dispose? if not, then handle next antenna, go to step 120); If, then export user's downlink composite weighted vector, dispose.

Wherein, step 130) correction of user's downlink composite weights includes, but are not limited to following two kinds of schemes:

Scheme (one): on the antenna of transmission power overload, calculate the proportionality coefficient between compound weights power of each user and the gross power, and reduce each user's downlink composite weights power of dedicated channel in proportion, as shown in Figure 2, specifically may further comprise the steps:

201) calculate on m the power overload antenna, the proportionality coefficient between each user's downlink composite weights power and the gross power.

On m the power overload antenna, a k user's downlink composite weights power and the proportionality coefficient between the gross power be expressed as

${\mathrm{\&gamma;}}^{(k,m)}=\frac{{\left|{\mathrm{\&omega;}}^{(k,m)}\right|}^2}{\underset{k=0}{\overset{K-1}{\mathrm{\&Sigma;}}}{\left|{\mathrm{\&omega;}}^{(k,m)}\right|}^2}=\frac{{\left|{\mathrm{\&omega;}}^{(k,m)}\right|}^2}{F^{\left(m\right)}},k=\mathrm{0,1},...,M$

202), reduce each user's downlink composite weights power in proportion, that is: for m power overload antenna

The power that needs to reduce on m power overload antenna is

ΔF ^(m)＝F ^(m)-1

For m power overload antenna, k user's downlink composite weights power reduces in proportion, promptly

${\left|{\stackrel{\&CenterDot;}{\mathrm{\&omega;}}}^{(k.m)}\right|}^2={\left|{\mathrm{\&omega;}}^{(k,m)}\right|}^2-{\mathrm{\&gamma;}}^{(k,m)}\&CenterDot;\mathrm{\&Delta;}{F}^{\left(m\right)}$

${\stackrel{\&CenterDot;}{\mathrm{\&omega;}}}^{(k,m)}={\mathrm{\&omega;}}^{(k,m)}\&CenterDot;\frac{\sqrt{{\left|{\mathrm{\&omega;}}^{(k,m)}\right|}^2-{\mathrm{\&gamma;}}^{(k,m)}\&CenterDot;\mathrm{\&Delta;}{F}^{\left(m\right)}}}{\left|{\mathrm{\&omega;}}^{(k,m)}\right|}$

Simple in order to express, can be designated as

${\mathrm{\&omega;}}^{(k,m)}={\stackrel{\&CenterDot;}{\mathrm{\&omega;}}}^{(k,m)}$

Scheme (two): on the transmission power overload antenna,,, as shown in Figure 3, specifically may further comprise the steps with certain power step size, by the user's downlink composite weights power that reduces dedicated channel from large to small in proper order successively or alternately according to the compound weights power of each user:

301), search for user's sequence number of maximum correspondence in the current downlink composite weights power for m power overload antenna.

On m the power overload antenna, user's sequence number of maximum correspondence is in the current downlink composite weights power

$\tilde{k}=\underset{k}{\arg }\left\{\underset{{\mathrm{\&omega;}}^{(k,m)}}{\max }\left[{\left|{\mathrm{\&omega;}}^{(k,m)}\right|}^2\right]\right\}$

For m power overload antenna, if the maximum of two or more users' downlink composite weights power equates then optional one of them user's sequence number.

302) for m power overload antenna, the downlink composite weights power of prominent user's correspondence reduces S (dB).

On m the power overload antenna, the downlink composite weights power of prominent user's correspondence reduces S (dB), is expressed as

$10.1g\left({\left|{\stackrel{\&CenterDot;}{\mathrm{\&omega;}}}^{(\tilde{k},m)}\right|}^2\right)10.1g\left({\left|{\mathrm{\&omega;}}^{(\tilde{k},m)}\right|}^2\right)-S$

Promptly

${\stackrel{\&CenterDot;}{\mathrm{\&omega;}}}^{(\tilde{k},m)}=\frac{{\mathrm{\&omega;}}^{(\tilde{k},m)}}{{10}^{S/20}}$

S represents step-length in the formula, common 0.1≤S≤2, and unit is dB.

303) recomputate the downlink transmission power overload flags parameters of m antenna correspondence.

Simple in order to express, on m the power overload antenna, revise afterwards that k user's downlink composite weight table is shown

${\mathrm{\&omega;}}^{(k,m)}=\left\{\begin{array}{cc}{\stackrel{\&CenterDot;}{\mathrm{\&omega;}}}^{(k,m)},& k=\tilde{k}\\ {\mathrm{\&omega;}}^{(k,m)},& k\&NotEqual;\tilde{k}\end{array}\right.$

Corresponding downlink transmission power overload flags parameters is

$F^{\left(m\right)}=\underset{k=0}{\overset{K-1}{\mathrm{\&Sigma;}}}{\left|{\mathrm{\&omega;}}^{(k,m)}\right|}^2$

304) down transmitting power of judging m antenna overload still whether? if go to step 301); Otherwise the step of revising the downlink composite weights finishes, that is:

If F ^(m)＞1, show that the transmitting power of m antenna is still transshipped, then go to step 301), continue to realize the overload protection measure; If F ^(m)≤ 1, the transmitting power that shows m antenna has reached does not transship requirement, and then the step of the correction downlink composite weights of m antenna finishes.

Claims (10)

1. a smart antenna downlink transmission power overload control method is characterized in that, may further comprise the steps:

1.1) overload identification: based on each each user's of antenna descending beam shape-endowing weight value vector w ^(k)={ w ^{(k, m)}, antenna proofreaies and correct weighted vector $w_{\mathrm{AC}}=\left\{w_{\mathrm{AC}}^{\left(m\right)}\right\},$ Power control factor ρ _PC ^(k)And power back-off factor-alpha ^(k), calculate each user's downlink composite weights ω of each antenna ^{(k, m)}And each user's downlink composite weights mould quadratic sum of correspondence self antenna

Wherein ${\mathrm{\&omega;}}^{(k,m)}={\mathrm{\&alpha;}}^{\left(k\right)}\&CenterDot;w_{\mathrm{AC}}^{\left(m\right)}\&CenterDot;w^{(k,m)}\&CenterDot;{\mathrm{\&rho;}}_{\mathrm{PC}}^{\left(k\right)},$ K refers to k user, is total to K user, and m refers to m antenna;

1.2) overload control: if described mould quadratic sum

Greater than 1, then revise user's downlink composite weights ω of respective antenna ^{(k, m)}Make described mould quadratic sum Be less than or equal to 1.

2. according to the described control method of claim 1, it is characterized in that described step 1.2) in to revise be each the user's downlink composite weights ω that reduces respective antenna in proportion ^{(k, m)}

3. according to the described control method of claim 2, it is characterized in that described ratio is meant user's downlink composite weights mould square | ω ^{(k, m)}| ²With each user's downlink composite weights mould quadratic sum

Proportionality coefficient.

4. according to the described control method of claim 1, it is characterized in that described step 1.2) in to revise be to described user's downlink composite weights or revised user's downlink composite weights ω ^{(k, m)}Sort from big to small by the mould square value, toply reduce its mould square until described mould quadratic sum to wherein coming at every turn with fixed size

Be less than or equal to 1.

5. according to the described control method of claim 4, it is characterized in that described to come top be one of maximum or maximum.

6. according to the described control method of claim 1, it is characterized in that described power back-off factor-alpha ^(k)Be expressed as ${\mathrm{\&alpha;}}^{\left(k\right)}=\frac{\sqrt{M}\&CenterDot;\sqrt{\underset{w_m^{\left(k\right)}}{\max }\left[{\left|w^{(k,m)}\right|}^2\right]}}{\sqrt{\underset{m=0}{\overset{M-1}{\mathrm{\&Sigma;}}}|w^{(k,m)}{|}^2}}\&CenterDot;{\mathrm{\&eta;}}^{\left(k\right)},$ η wherein ^(k)It is the gain compensation factor between k user's different beams forms.

7. according to the described control method of claim 5, it is characterized in that described wave beam comprises business beam and broadcast beam; η ^(k)Span can be $\frac{M}{4}\&le;{\mathrm{\&eta;}}^{\left(k\right)}\&le;4\&CenterDot;M.$

8. according to the described control method of claim 1, it is characterized in that this control method is applied in the synchronous CDMA communications system that adopts TDD, described descending beam shape-endowing weight value vector w ^(k)={ w ^{(k, m)}Obtain according to measuring corresponding up received signal or channel estimating.

9. described according to Claim 8 control method is characterized in that, the synchronous CDMA communications system of described employing TDD can be the TD-SCDMA system of 1.28Mcps or 3.84Mcps.

10. according to the described control method of claim 1, it is characterized in that this control method is applied in the synchronous CDMA communications system that adopts FDD, described descending beam shape-endowing weight value vector w ^(k)={ w ^{(k, m)}Reach the angle according to ripple and estimate to obtain.

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