CN101267237B - 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=(wAC<(m)>), 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 corresponding to the antenna itself shown in the description; wherein omega<(k, m)>=alpha<(k)>* wAC<(m)>* rho PC<(k)>; and if the modular multiplication summation 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 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 up of aerial array, utilize transmission of wireless signals spatial character and Digital Signal Processing, can realize the estimation of shape-endowing weight value vector and down beam shaping, thereby reach the object 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—Synchronous Code Division Multiple Access cdma communication system that adopts TDD mode, its upper and lower channel meets symmetrical requirement, if employing smart antenna, can realize each user's shape-endowing weight value vector estimation according to uplink receiving signal corresponding to aerial array or channel estimating, and then complete down beam shaping, solve preferably the problems such as anti-multipath interference and anti-multiple access interference.

In antenna system, the down transmitting power of antenna is subject to the direct impact of all multi-parameters, comprise descending beam shape-endowing weight value vector, antenna calibration weighted vector, power control factor and the power back-off factor etc., and there is undoubtedly the upper limit in the transmitting power of each passage.Owing to thering is certain independence between above-mentioned parameter; between multiple parameters, interact, therefore, in specific situation, may there is transshipping phenomenon in the transmitting power of some antenna channels; if the safeguard measure of employing, must cause system link performance and network performance obviously to decline.

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, in predetermined time interval, according to N power per liter and M predetermined alternating sequence that falls power, the down transmitting power of base station is controlled, can, at the up-link wireless link of base station side under desynchronizing state, avoid the abnormal power control of base station down transmitting power, make the down transmitting power of base station keep stable.The method can be controlled total down transmitting power control of base station side, but has only considered the impact of power control factor parameter, does not distinguish each antenna channels, cannot judge whether single-antenna transmission power transships.

Summary of the invention

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

1.1) overload identification: the descending beam shape-endowing weight value vector w based on the each user of each antenna ^(k)={ w ^{(k, m)}, antenna calibration weighted vector power control factor 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 k refers to k user, K user altogether, and m refers to m antenna, altogether M antenna;

1.2) overload is controlled: if described mould quadratic sum be greater than 1, 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) in to revise be the each user's downlink composite weights ω that reduces in proportion respective antenna ^{(k, m)}.

According to control method provided by the invention, described ratio refers to 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) in to revise be 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 mould square value, reduce its mould square until described mould quadratic sum to wherein coming foremost with fixed size at every turn be less than or equal to 1.

According to control method provided by the invention, described in to come top be one of maximum or maximum, that is: maximum can be same large one or more, only appoints to get that wherein any comes foremost when multiple.

According to control method provided by the invention, described power back-off factor-alpha ^(k)be expressed as wherein η ^(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

According to control method provided by the invention, described different beams forms and 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 uplink receiving 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 according to ripple reach angle estimate obtain.

Smart antenna downlink transmission power overload control method provided by the invention, based on descending beam shape-endowing weight value vector, antenna calibration weighted vector, 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 transmission power transships and antenna correction respective user downlink composite weights to transmission power overload, thereby can transship control to any single antenna of transmission power overload in smart antenna, the transmitting power of each antenna is met design requirement, safeguards system equipment is normally worked, and reduce as far as possible the performance loss of system.

brief description of the drawings

Below in conjunction with the drawings and specific embodiments, further the present invention is described in detail.

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

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

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

Embodiment

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

110), based on descending beam shape-endowing weight value vector, antenna calibration weighted vector, power control factor and the power back-off factor, calculate downlink transmission power overload flags parameters and corresponding each 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 antenna calibration weighted vector is $w_{\mathrm{AC}}=\left\{w_{\mathrm{AC}}^{\left(m\right)}\right\}{|}_{m=\mathrm{0,1},\&CenterDot;\&CenterDot;\&CenterDot;,M-1};$ K user's the power back-off factor is α ^(k); Number of users is K, and antenna number is M.

Calculate m the downlink transmission power overload flags parameters that antenna is corresponding, 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＝0，1，…，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 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 broadcast beam, conventionally $\frac{M}{4}\&le;{\mathrm{\&eta;}}^{\left(k\right)}\&le;4\&CenterDot;M.$

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

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

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

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

Do are 140) whether all antennas all disposed? if not, process next antenna, go to step 120); If so, the downlink composite weighted vector of exporting user, is disposed.

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

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

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

Proportionality coefficient on m power overload antenna, between a k user's downlink composite weights power and gross power is 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＝0，1，...，M

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

On m power overload antenna, need the power reducing to be

ΔF ^(m)＝F ^(m)-1

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

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

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

Simple in order to express, can be designated as

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

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

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

On m power overload antenna, in current downlink composite weights power, user's sequence number corresponding to maximum is

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

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

302), for m power overload antenna, downlink composite weights power corresponding to prominent user reduces S (dB).

On m power overload antenna, downlink composite weights power corresponding to prominent user reduces S (dB), is expressed as

$10\&CenterDot;\lg \left({\left|{\stackrel{\&CenterDot;}{\mathrm{\&omega;}}}^{(\tilde{k},m)}\right|}^2\right)=10\&CenterDot;\lg \left({\left|{\mathrm{\&omega;}}^{(\tilde{k},m)}\right|}^2\right)-S$

?

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

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

303) recalculate m the downlink transmission power overload flags parameters that antenna is corresponding.

Simple in order to express, on m power overload antenna, revise k user's downlink composite weight table afterwards and be 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) whether overload still of the down transmitting power that judges m antenna? if so, go to step 301); Otherwise the step of revising downlink composite weights finishes, that is:

If F ^(m)>1, shows that the transmitting power of m antenna is still transshipped, and goes to step 301), continue to realize overload protection measure; If F ^(m)≤ 1, the transmitting power that shows m antenna has reached does not transship requirement, and 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, comprises the following steps:

1.1) overload identification: the descending beam shape-endowing weight value vector w based on the each user of each antenna ^(k)={ w ^{(k, m)}, antenna calibration weighted vector power control factor 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 k refers to k user, K user altogether, and m refers to m antenna, altogether M antenna;

1.2) overload is controlled: if described mould quadratic sum be greater than 1, 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. control method according to claim 1, is characterized in that described step 1.2) in to revise be the each user's downlink composite weights ω that reduces in proportion respective antenna ^{(k, m)}.

3. control method according to claim 2, is characterized in that, described ratio refers to user's downlink composite weights mould square | ω ^{(k, m)}| ²with each user's downlink composite weights mould quadratic sum proportionality coefficient.

4. control method according to claim 1, 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 mould square value, toply reduce its mould square until described mould quadratic sum with fixed size to wherein coming at every turn be less than or equal to 1.

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

6. control method according to claim 1, is characterized in that described power back-off factor-alpha ^(k)be expressed as wherein η ^(k)it is the gain compensation factor between k user's different beams forms.

7. control method according to claim 6, is characterized in that, described different beams forms and comprises business beam and broadcast beam; η ^(k)span can be

8. control method according to claim 1, 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 uplink receiving signal or channel estimating.

9. control method according to claim 8, 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. control method according to claim 1, 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)}according to ripple reach angle estimate obtain.