CN1354570A - Up-line load linear estimation method of wide-band code division multiple address system - Google Patents

Abstract

The invention discloses a method for linearly estimating the upload in WCDMA system. The invention method is adopted in the controller of base station. Based on the powr measured by base station, the relevant information through lub interface is transferred to wireless network controller where the work for estimating the upload is done by sub process for estimating the upload in wireless resources management layer. The invented method first puts forward the issue of linear measurement of upload estimation and gives a estimating formula with good linearity and within region of load, by using the measuring value of received total power as variable. The invention corrects serious non-linearity in traditional estimating method, makes the estimation more accurate.

Description

A kind of up-line load linear estimation method of wide-band code division multiple address system

The present invention relates to WCDMA system uplink method of load estimation, belong to 3-G (Generation Three mobile communication system) one Wideband Code Division Multiple Access (WCDMA) (WCDMA) field.

Development is very rapid since mobile communication system begins extensive use the nineties, a short part that became human lives's interwoveness in several years, under the promotion of Internet fast development, people have greatly promoted the development of 3-G (Generation Three mobile communication system) (IMT-2000) to craving for of mobile Internet simultaneously.The WCDMA technology is the mainstream technology of 3-G (Generation Three mobile communication system), the WCDMA system standardization organize 3GPP 99 years by and the wireless interface technology standard of having issued Release 99 ' version.Because need to consider between the 3-G (Generation Three mobile communication system), the compatibling problem between the third generation and the second generation, the network standardization flow of research of IMT-2000 comparatively lags behind than the Standardization Research process of wireless access network (RAN).Simultaneously, because the soft capacity characteristic of cdma system, and power system capacity is also relevant with wireless environment, traffic performance etc. with load, therefore 3GPP is difficult to system-level control method is worked out unified standard, and it is the method for narrowband CDMA that second generation mobile communication system is mainly still adopted in the estimation of power system capacity and load.

3-G (Generation Three mobile communication system) is that loaded service is different with the main distinction of second generation mobile communication system, second-generation system is mainly based on voice service, third generation system is then based on multimedia service, voice service and Packet data service are laid equal stress on, and support the high speed data transfer up to 2Mbps.

The load control of WCDMA system is divided into several aspects, because Radio Resource is very in short supply, main bottleneck is on the wireless link between base station (Node-B) and the mobile subscriber terminal (UE), therefore the load estimation and the control of air interface seem extremely important, and the load estimation correctness is the prerequisite of load control.A general base station (Node B) is divided into 3 sub-districts (cell), and respectively load estimation and control is carried out in each sub-district.The load of sub-district is divided into uplink load and downlink load.At present, estimate two kinds of methods of the general employing of uplink load: one is based on the method for base station received power, and two are based on the method for throughput.Concrete " wireless access of the WCDMA-3G (Third Generation) Moblie of UMTS " book of being shown based on the 3GPP protocol specification with reference to people such as the Harri Holma of Nokia Telecommunications.

At present as follows based on the uplink air load estimation formula of power method: ${\mathrm{\η}}_{\mathrm{UL}}=1-\frac{P_N}{P_{\mathrm{total}}}=1-\frac{1}{N_r}---\left(1\right)$

(1) formula satisfies N _r=1, η _UL=0; N _r=∞, η _UL=1 edge-restraint condition.

η _ULBe uplink load, P _NBe the thermal noise power relevant, comprised white noise and receiver system noise with ambient temperature.The receiver system noise comprises parts such as antenna for base station noise, feeder loss, receiver internal noise.P _TotalBe the measured value that the base station receives gross power, comprise the interference power of thermal noise power, multiple access interference power and peripheral cell.N _rBe the noise climbing number, be illustrated in the WCDMA system insert the user after, disturb the degree of comparing rising with thermal noise at base station receiving terminal multiple access.This shows, adopt base station measurement to receive gross power and estimate that the method for uplink load has practical significance, can be easily calculate the aerial load of up link during from the power measurement fructufy that periodically reports.

Be provided with N user and insert a sub-district, consider the interference of peripheral cell, then have:

P _otal＝P _N+P _s1+P _s2+P _s3+...P _sN+P _othercell $N_r=\frac{P_{\mathrm{total}}}{P_N}=1+\frac{P_{s1}}{P_N}+\frac{P_{s2}}{P_N}+\…+\frac{P_{\mathrm{sN}}}{P_N}+\frac{P_{\mathrm{othercell}}}{P_N}$

As seen, noise climbing number N _rAlways greater than 1.

N _rPhysical meaning be that the multiple access interference power is suitable with the background heat noise power, at this moment N when to insert an aerial speed be 960Kbps professional _r=2; The rest may be inferred, when the service access of 6 960Kbps, and N _r=7.By the technical specification of 3-G (Generation Three mobile communication system), because the quadrature code tree is limit, a user can only have the up channel of 6 960Kbps, i.e. N at most _r=7 o'clock near up full load.

If according to the curve that formula (1) is made, clearly, curve has presented the severe nonlinear characteristic.At N _rHour slope is very big, works as N _rPresent saturation characteristics when big.For example from zero load when setting up the Radio Link of a 960Kbps, load only takes about 1/6 of load, load from 0 be increased to 50%! At N _rWhen big, as load only is 85.7% when load is 83.3%, 6 when setting up 5 wireless links, and as seen, the relation of load and noise climbing number is non-linear.For example, from 5 link to 6 links, load η _ULFrom 83.3% to 85.7%, load estimation presents great non-linear saturation characteristic, changes very for a short time, and receives the same order of magnitude of error that gross power is measured.Nonlinear characteristic caused under the high-speed data service situation to load measure inaccurate, can't carry out the accurate control of system loading, thereby be difficult to the operation stably under higher load condition of assurance system.Make the load of system's difficult control high-speed data service part when load control, and support the high speed data transfer maximum glamour place of 3-G (Generation Three mobile communication system) just to be the characteristic indication of 3-G (Generation Three mobile communication system).Therefore be necessary to adopt a kind of new, linear method to estimate the uplink load of sub-district.

The objective of the invention is to propose a kind of uplink load Linear Estimation method of under WCDMA system high speed data service situation, laod measurement accurately being controlled.The present invention proposes uplink load Linear Estimation method and comes the estimating uplink load, may further comprise the steps:

1) according to ambient temperature T ₀And base station (Node-B) receiver system equivalent noise coefficient F, calculate heat

Noise power, and be converted into numerical value P by the dB value _N, further may further comprise the steps;

(1) calculates the white noise power P _WN=kT ₀B, T ₀Be ambient temperature, k is Boltzmann

Constant is 1.38 * 10 ^-23Joule/° K, B is a communication bandwidth, the WCDMA system

Communication bandwidth be 5MHz.And pass through P _WN(dB)=101g (kT ₀B) calculate white noise

The dB value of acoustical power.

(2) calculate receiver noise power by receiver system equivalent noise coefficient F

P _R(dB)＝101gF。

(3) by P _N(dB)=P _WN(dB)+P _R(dB) the dB value of calculating noise power.

(4) by

Calculate the numerical value of thermal noise power.

2) from Radio Resource control (RRC) signaling, obtain the received power measured value that the base station reports, and by

Following formula is converted into numerical value P with the dB value of received power _Total $P_{\mathrm{total}}={10}^{0.1P_{\mathrm{total}}\left(\mathrm{dB}\right)}$

3) by The calculating noise climbing number.

4) according to following new uplink load Linear Estimation formula calculation plot uplink load amount η _UL ${\mathrm{\η}}_{\mathrm{UL}}=1-e^{\frac{1-N_r}{{10}^{(1-0.1N_r)}}}$

5) η that will load _ULConvert the interface function value to and export to admittance control and load control subprocess.The present invention is further illustrated below in conjunction with accompanying drawing.

Fig. 1 is based on uplink air load estimation formula function curve diagram in the prior art; Fig. 2 is the flow chart of the inventive method; Fig. 3 is based on the uplink air of the present invention linear estimation formulas function curve diagram of loading; Fig. 4 is prior art and the uplink air of the present invention linear estimation formulas function curve comparison diagram of loading.Fig. 1 is present uplink air load estimation formula function curve diagram; Promptly based on formula

The curve of being done.

As seen from the figure, curve has presented the severe nonlinear characteristic, and promptly the relation of uplink load and noise climbing number is non-linear.At N _rHour slope is very big, works as N _rPresent saturation characteristics when big.For example never load (zero load) is when setting up the Radio Link of 1 960Kbps, and load only takes about 1/6 of load, and the noise power climbing number is loaded and is increased to 50% from 0 by 1 to 2;

At N _rWhen big, as time load is 83.3% to set up 5 wireless links, article 6, load only is 85.7% the time, during from 5 to 6, load variations is very little, as seen, load and the relation of noise climbing number are non-linear and the same order of magnitude of measure error power, therefore present method is difficult to the true load of measurement system by power measurement values calculated load value, especially under the high-speed data service situation, it is inaccurate that load is measured, and can't carry out the accurate estimation and the control of system loading, thus the stability of system's operation when being difficult to guarantee higher load.And support the high speed data transfer maximum glamour place of 3-G (Generation Three mobile communication system) just to be the characteristic indication of 3-G (Generation Three mobile communication system).Therefore be necessary to adopt a kind of new, linear method to estimate the uplink load of sub-district.Fig. 2 is a method flow diagram of the present invention.In order to obtain the noise climbing number of system cell, at first want the total thermal noise power of calculation base station, also to from reporting, base station measurement obtain the base station total received power.Be exactly total the numerical value of total received power divided by noise power numerical value noise climbing number.Because measuring the performance number and the thermal noise power that report is unit with the decibel, must convert numerical value to by decibel value.As variable, substitution formula (2) calculates can obtain cell uplink load accurately with the noise climbing number, load is exported to admitted control and load to control the foundation of subprocess as judgement.Fig. 3 is based on the uplink air of the present invention linear estimation formulas function curve diagram of loading; Promptly based on formula that the present invention creates The curve chart of being done.

In order to overcome the defective of present method of load estimation, at N _rHour high slope and N _rSaturation characteristic when big, constructed one brand-new, keeping linear load estimation formula in a big way, see formula (2), curve is seen Fig. 2.As seen from Figure 2, new uplink load estimation formulas still keeps better linearity near full load the time, can truly reflect the uplink load of system in the scope of measuring of load.See Fig. 3 with present method contrast.Can see that by Fig. 3 new method has the better linearity and the wideer range of linearity than present method, can satisfy the needs of system loading control.

The core concept of formula of the present invention is clearly to have proposed the linear measure of load estimation first, and to have provided to receive the gross power measured value be variable, formula that the linearity is splendid in load range.Load estimation is the prerequisite of system's control, and the precision of system's control depends on the precision of load estimation, and the efficient of system's operation and stability depend on the precision of system's control again; Load estimation algorithm subprocess belongs to high-rise RRM (RRM) algorithm of radio network controller (RNC), measure the gross power of its reception in physical layer by Node B base station, each frame (10ms) reports the high-rise RRM functional module of once giving among the RNC by the RRC signaling, finishes load estimation work by RRM.Formula of the present invention still satisfies N _r=1, η _UL=0; N _r=∞, η _UL=1 boundary constraint relation is worked as N _r=2 o'clock, η _UL=14.3%; N _r=3 o'clock, η _UL=32.9%; N _r=4 o'clock, η _UL=52.9%; N _r=5 o'clock, η _UL=71.8%; N _r=6 o'clock, η _UL=86.3%; N _r=7 o'clock, η _UL=95.1%; Substantially near linear characteristic.Fig. 4 is prior art and the uplink air of the present invention linear estimation formulas function curve comparison diagram of loading.The curve of the inventive method is shown in the dotted line among the figure.As seen from Figure 4, the linearity of this method method more used than present prior art is far better.In the greatest physical limit of power (6 960Kbps physical channel) of WCDMA system, the scope of load from 0% to 95% has kept better linearity.In sum, the present invention adopts in base station controller (RNC), the received power that measures according to base station (Node B) is sent to high-rise RRM (RRM) the load estimation algorithm subprocess of RNC (radio network controller) by Iub interface, finishes load estimation work by it.The core concept of described method is the linear measure problem that has clearly proposed load estimation first, and has provided to receive the gross power measured value to be variable, the estimation formulas of the fine linearity is arranged in load range.The present invention is used for the network design of 3-G (Generation Three mobile communication system) and the load estimation and the control of the network operation, can reach that uplink load is estimated accurately, load control easily, improve wireless resource utility efficiency, improve network operation stability, reduce the percent of call lost and switch the effect of cutting off rate.The present invention is not limited to the WCDMA system.After adopting the new method of load estimation of the present invention's proposition, load estimation is seriously non-linear when having revised original high-speed data service and inserting, make the estimation of system uplink load more accurate, under the prerequisite that guarantees system stable operation, admit more business as much as possible, improved the efficient of system, reduce the percent of call lost, improved service quality and economic benefit.

Claims (5)

1, uplink load Linear Estimation method in a kind of WCDMA system is characterized in that may further comprise the steps:

Step 1: calculate thermal noise power, and be converted into numerical value P by the dB value _N

Step 2: from Radio Resource control (RRC) signaling, obtain the received power measured value that the base station reports,

And the dB value of received power is converted into numerical value P _Total

Step 3: by

The calculating noise climbing number;

Step 4: according to following new uplink load Linear Estimation formula calculation plot uplink load amount η _UL ${\mathrm{\η}}_{\mathrm{UL}}=1-e^{\frac{1-N_r}{{10}^{(1-0.1N_r)}}};$

Step 5: η will load _ULConvert the interface function value to and export to admittance control and load control subprocess.

2, uplink load Linear Estimation method in the WCDMA according to claim 1 system, it is characterized in that: described step 1 comprises:

At first calculate the white noise power P _WN=kT ₀B, and pass through P _WN(dB)=101g (kT ₀B) calculate white noise

The dB value of power, wherein T ₀Be ambient temperature, k is a Boltzmann constant, is 1.38 * 10 ^-23Joule/° K,

B is a communication bandwidth, and the communication bandwidth of WCDMA system is 5MHz;

Secondly calculate the receiver noise power P by receiver system equivalent noise coefficient F _R(dB)=101gF;

Then by P _N(dB)=P _WN(dB)+P _R(dB) the dB value of calculating noise power;

At last by Calculate the numerical value of thermal noise power.

3, uplink load Linear Estimation method in the WCDMA according to claim 1 system, it is characterized in that: the dB value of received power is converted into numerical value P in the described step 2 _TotalBe according to following formula: $P_{\mathrm{total}}={10}^{0.1P_{\mathrm{total}}\left(\mathrm{dB}\right)}.$

4, uplink load Linear Estimation method in the WCDMA according to claim 1 system, it is characterized in that: described step 1 is according to ambient temperature T ₀And base station (Node-B) receiver system equivalent noise coefficient F calculating.

5, uplink load Linear Estimation method in the WCDMA according to claim 1 system is characterized in that:

In the step 4 Formula still satisfies N _r=1, η _UL=0; N _r=∞, η _UL=1 boundary constraint relation.

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