CN1145295C - Method for soft switching subzone of mobile station in CDMA communication system - Google Patents

Abstract

The present invention discloses a cell soft switching method for a mobile station in a code division multiple access communication system. In the method, the influence conditions of reverse link interference are mainly added, and the performance of reverse links is determined by forward fading and reverse loading. The method can comprehensively evaluate the conditions of forward link interference and reverse link interference and also comprehensively consider the load and the distance fading of forward links and reverse links of cells. Consequently, the cell situations can be thoroughly evaluated during cell selection through soft switching; when the selectable service cells are in a large quantity, the most suitable branches of soft switching can be conveniently established so as to ensure that the service cell which brings the maximum gain to a system is selected.

Description

The method of soft switching subzone of mobile station in the code division multiple address communication system

Technical field

The present invention relates to wide-band mobile communication system, more specifically refer in the CDMA2000 system, the method for soft switching subzone of mobile station in a kind of code division multiple address communication system.

Background technology

Can carry out soft handover is a distinctive advantage of code division multiple access (CDMA) system.It refers in particular to travelling carriage in the switching between different districts (or sector) on the frequency, generally comprise three steps, 1) travelling carriage is periodically searched for the pilot signal of all available PN (please mark Chinese implication) biasing on current frequency, die down the grow of neighbor cell with the pilot tone of finding original Serving cell; 2) travelling carriage reports pilot strength measurement report (PSMM) to give base station controller (BSC), base station controller (BSC) allows the new sub-district be travelling carriage distribution service channel by base station transceiver (BTS) issuing message, connect, this moment, travelling carriage did not interrupt with being connected yet of former sub-district, entered the diversity status that while and a plurality of base station transceiver (BTS) connect; 3) along with the former further away from each other sub-district of travelling carriage, after former cell signal is reduced to a certain following a period of time of thresholding, travelling carriage reports pilot strength measurement report (PSMM) to make former sub-district end and being connected of travelling carriage for base station controller (BSC), base station transceiver (BTS) issuing message.Provide service for travelling carriage separately by new sub-district.So far, soft switching process finishes.For the purpose of the statement, do not consider the situation of sectorization in the sub-district here for convenience.

Soft handover may be to be moved by location of mobile station to cause, also may be to wait other reasons to cause because wireless environment changes, and in a word, causes owing to wireless receiving situation between sub-district and travelling carriage changes.All patterns available of travelling carriage continuous measurement, as long as record pilot tone and base station controller (BSC) permission of intensity greater than certain thresholding, just foundation and its respective cell is connected.Soft handover is that the benefit that system brings has: 1) really realized seamless switching.Travelling carriage is remaining business when soft handover, do not have the dropped calls that hard cut measurement causes, and has reduced the possibility of call drop.When 2) travelling carriage kept being connected with a plurality of base stations simultaneously, base station controller (BSC) had improved the frame error rate of reverse received signal by diversity, has reduced the required transmitting power of travelling carriage, has reduced the interference on the reverse link, has increased reverse capacity.

In order to obtain best diversity and behind soft handover, to enter best cell, select forward direction wireless connections better cell when generally requiring soft handover, what the travelling carriage diversity merged like this is optimum received signal.Can reduce the required transmitting power of forward direction.But this only considers that the cell selecting of forward direction is incomplete, also should be taken into account reverse influence.On the reverse link, when being in soft changing state, travelling carriage generally neighbor cell has been constituted strong jamming, if the sub-district that insert this moment can make required back emitted power minimum, the interference of adjacent sub-district is dropped to minimum, just can increase the reverse capacity of system to greatest extent.

Therefore soft switching subzone is selected also should consider following three aspect factor: 1) range attenuation.2) interference of forward link.3) interference of reverse link.In conventional method, switch decision is only based on the measurement to the pilot frequency intensity of forward link, measurement be the E of pilot signal _c/ I _oValue, what this value reflected is the interference size of base station distance distance and forward link, and does not embody the influence of reverse load.In the system (as IS-95) of professional symmetry, preceding reverse link load quite, can consider the interference of reverse link in addition, and business is asymmetric in the CDMA2000 system, if the forward direction load is greater than reverse load, promptly when the forward direction capacity limit is the bottleneck of service access, for simplicity, also can not consider the influence of reverse load.Yet when if some zone reverse load is loaded greater than forward direction, the selection of sub-district needs to take all factors into consideration the factor of above three aspects.Although otherwise the transmitting power of the sub-district forward direction needs that might occur selecting is little, because reverse load is heavy, transmission power of mobile station height, reverse capacity reduce and have limited the overall performance of system.

Existing soft hand-off is based on the E of pilot tone when selecting the sub-district _c/ I _o, value, this value can only reflect the decline situation of signal on the forward link and the interference size of forward link, the disturbed condition that can't reflect reverse link, it is better to make travelling carriage insert a forward link like this, but in the bigger sub-district of back emitted power, has but reduced reverse capacity.In fact, because forward link means that well forward emitting power is less, so this means and to take all factors into consideration forward emitting power and back emitted power.Obviously hour be optimum all at the two.Yet may exist such situation, travelling carriage and sub-district 1 connect, and the forward emitting power that needs is little but back emitted power is big; Travelling carriage and sub-district 2 connect, and the forward emitting power that needs is big but back emitted power is little, and should select which sub-district to insert needs the influence of this two aspects factor of overall merit to system.Therefore, existing soft handover method only emphasizes that an aspect is perfect inadequately.

Summary of the invention

For this reason, the objective of the invention is to propose soft switching subzone of mobile station method in a kind of code division multiple address communication system, this method can be taken all factors into consideration the load and the distance decline of reverse link before the sub-district, increase the influence condition of return link interferences, when soft handover is selected the sub-district, can more fully estimate the sub-district, guarantee to select the Serving cell that makes the system gain maximum.

To achieve these goals, the present invention adopts following technical scheme; This soft switching subzone method is based on code division multiple access system, in this system, comprise a base station controller, several base station transceivers by this base station controller control, by travelling carriage to the reverse link of the base station transceiver that activates with by the forward link of the base station transceiver that activates to travelling carriage, travelling carriage and each base station transceiver include a transreceiver, it is characterized in that this method may further comprise the steps:

A makes at least one base station transceiver in travelling carriage and this system set up Traffic Channel, and travelling carriage is periodically searched for the pilot tone of using each base station transceiver on the frequency;

B, base station controller be according to the pilot tone number in the travelling carriage pilot tone Active Set, determines that Active Set adds thresholding or Active Set dynamically adds thresholding, and Active Set is added thresholding or Active Set dynamically add thresholding and be handed down to travelling carriage;

C, the pilot frequency intensity of each base station transceiver of travelling carriage continuous detecting also reports base station controller;

D, base station controller is judged the pilot tone number in the current Active Set of travelling carriage and judged result is handed down to travelling carriage and relevant base station transceiver by forward link;

E, the low sub-district of base station controller selective system performance preferred value Es is rejected in the Active Set and maybe will not be entered, again by the pilot tone assignment message with the cell notification travelling carriage of choosing, travelling carriage is according to the instruction foundation of base station controller and being connected of new sub-district, return step a after being finished again, wherein, described systematic function preferred value Es and forward link interference, return link interferences and range attenuation negative correlation;

F, above step cycle is carried out, till travelling carriage winding-up state.

Because the soft switching subzone of mobile station method has adopted above-mentioned method in the code division multiple address communication system of the present invention, increase the influence condition of return link interferences, reverse link performance is judged with forward direction decline and reverse load, therefore, the interference of method energy overall merit forward link of the present invention and the disturbed condition of reverse link, can also take all factors into consideration the load and the distance decline of reverse link before the sub-district, when selecting the sub-district, soft handover can more fully estimate the sub-district situation, at optional Serving cell more for a long time, be convenient to set up optimal soft handover branches, guarantee to select the Serving cell that makes the system gain maximum.

Description of drawings

Below in conjunction with drawings and Examples, method of the present invention is done one explains:

Fig. 1 is the code division multiple address communication system principle schematic.

Fig. 2 is in code division multiple address communication system, travelling carriage and sub-district schematic diagram that connects.

Fig. 3 is in code division multiple address communication system, travelling carriage and a plurality of sub-district schematic diagram that connects.

Fig. 4 method flow schematic diagram of the present invention.

Embodiment

See also shown in Figure 1, usually, in code division multiple address communication system, at least comprise a base station controller 11, by a plurality of base station transceiver 121～12N (the corresponding sub-district of each base station transceiver) of this base station controller 11 controls, by travelling carriage 13 to the reverse link of the base station transceiver (BTS) that activates with by the base station transceiver of activation forward link to travelling carriage 13.Wherein, travelling carriage 13 comprises a transreceiver, and each base station transceiver also includes a transreceiver.

During non-switching state, 13 of travelling carriages detect the pilot tone of an intensity greater than Active Set adding thresholding T_ADD, promptly have only the base station transceiver of an activation and travelling carriage 13 foundation to get in touch.The pilot tone that adds thresholding T_ADD if any a plurality of intensity the earth Active Sets, then might set up with a plurality of base stations simultaneously and get in touch, promptly set up a plurality of soft handover branches, see Fig. 2, consider that setting up branch can reduce forward-link capacity, and too much branch has little significance to backward gain, and soft branches generally is not more than 3.

In general, travelling carriage makes the less sub-district of forward emitting power because of forward direction E when selecting the sub-district after the access _c/ I _oBe worth greatlyyer, the lower-powered sub-district of required back emitted is should signal-to-jamming ratio relatively large when satisfying identical demodulation threshold, this require corresponding Radio Link decline little, disturb little.But oppositely decline also can't accurately record at present, can only be with the forward direction approximate evaluation that declines.

When soft switching subzone is selected, if select the heavy or big sub-district that oppositely declines of reverse load, because the signal-to-jamming ratio on this link is less relatively, when back emitted power is constant, the signal frame error rate that this cell base station receives is bigger, after reverse diversity merged, the back emitted power that power control requires down was also bigger.It is bigger than inserting the back emitted power that other reverse loads sub-district light or that decline little needs to insert this sub-district when that is to say soft handover.And transmission power of mobile station is big more, and is just big more to the reverse interference of each sub-district.Therefore when selecting, also should preferentially select the sub-district that reverse load is light, decline is little in conjunction with the reverse link situation.

Based on above-mentioned consideration, soft switching subzone method of the present invention may further comprise the steps:

A, make move 13 with this system at least one base station transceiver set up Traffic Channel, travelling carriage 13 is in the service condition, the frequency of use is f1, travelling carriage 13 is periodically searched for the pilot tone of each base station transceiver 121-12N on the frequency f1.

B, base station controller 11 is according to the pilot tone number in the travelling carriage 13 pilot tone Active Sets, determine that Active Set adds thresholding T_ADD or Active Set dynamically adds thresholding T_ADD_DYC, and Active Set is added thresholding T_ADD or Active Set dynamically add thresholding T_ADD_DYC and be handed down to travelling carriage 13.The meaning that dynamically adds thresholding T_ADD_DYC is to work as the soft handover branches set up more for a long time, and the new branch that limiting gain is not high sets up.

C, the pilot frequency intensity of each base station transceiver 121-12N of travelling carriage 13 continuous detecting also reports base station controller 11.

D, the pilot tone number in 11 pairs of travelling carriages of base station controller, the 13 current Active Sets is judged and judged result is handed down to travelling carriage and relevant base station transceiver by forward link.

E, the low sub-district of base station controller 11 selective system performance preferred value Es is rejected in the Active Set and maybe will not be entered, again by the pilot tone assignment message with the cell notification travelling carriage of choosing 13, travelling carriage 13 returns step a again according to the instruction foundation of base station controller 11 and being connected of new sub-district after being finished.

F, above step cycle is carried out, till travelling carriage 13 winding-up states.

In described step b, if in the travelling carriage 13 pilot tone Active Sets when having only a pilot tone, then base station controller 11 issues Active Set and adds thresholding T_ADD and give travelling carriage; If when an above pilot tone was arranged in the travelling carriage 13 pilot tone Active Sets, then base station controller 11 issued Active Set dynamic threshold T_ADD_DYC and gives travelling carriage 13.

Described Active Set adds thresholding T ADD value by default, generally gets-13db; Described Active Set dynamically adds thresholding T_ADD_DYC value according to formula (1)

Obtain.

In described step c, the pilot frequency intensity of travelling carriage 13 each base station transceiver of continuous detecting also reports base station controller 11 and is meant when finding to have pilot frequency intensity to add thresholding T_ADD or Active Set when dynamically adding the pilot tone of thresholding T_ADD_DYC greater than Active Set, by pilot strength measurement report message this pilot tone is reported base station controller 11.

In described steps d, when the pilot tone number in 11 pairs of current Active Sets of travelling carriage of base station controller is judged, if the pilot tone number less than 3 o'clock, then directly adds new pilot tone in the Active Set; If the pilot tone number was more than or equal to 3 o'clock, because preceding back emitted power is relatively independent, overall merit can adopt weighted sum to the influence of system, then according to formula (2)

$\mathrm{Es}=\frac{\mathrm{\α}}{P_f/P_{f\_\max }}+\frac{\mathrm{\β}}{P_r/P_r\_\max }.............\left(2\right)$

Calculate the pilot tone in the current Active Set and the systematic function preferred value Es of new pilot tone, select the minimum pilot tone of preferred value, if this pilot tone is in the current Active Set, then delete from Active Set, if this pilot tone is new pilot tone, then refusal adds Active Set.

In the formula (2), Es is the systematic function preferred value of obtaining, the cell selecting when judging soft handover by this value, and preferred this value is set up soft handover branches than higher sub-district.Pf is the forward direction Initial Trans, i.e. the required Initial Trans in base station.Pr is reverse Initial Trans, i.e. the required transmitting power of travelling carriage.P _{F_max}Be the maximum transmission power that forward direction distributes to unique user, α is positive weights, and the reflection forward emitting power is to the influence of systematic function, and β also is positive weights, and reflection back emitted power is to the influence of systematic function.These two values are set in background data base, can be by system's adjustment.Simplify the operation or reverse load does not overweight under the situation of forward direction load at needs, can get β=0.

Described formula (2) $\mathrm{Es}=\frac{\mathrm{\α}}{P_f/P_{f\_\max }}+\frac{\mathrm{\β}}{P_r/P_r\_\max }$ In, the forward direction Initial Trans Pf of travelling carriage appointment is according to formula (3)

$P_f=\min [P_{\mathrm{pilot}\_\mathrm{send}}\·10\frac{D+0.5M}{10}\·\frac{R}{W,}{P}_{\max }]............\left(3\right)$ Calculate.In the formula (3), P _fForward direction Initial Trans for the travelling carriage appointment;

P _{Pilot_send}Forward pilot intensity for base station;

D is that above-mentioned mobile station side demodulation is desired, the information bit bit energy that the base station must be satisfied and the ratio of disturbance spectrum density, promptly (mobile station side);

M is the content of the above-mentioned forward pilot intensity item that obtains, M=-210logPS;

P _MaxBe the operable maximum power of travelling carriage.

And reverse Initial Trans Pr is according to formula (4)

$P_r=\frac{{\left(\frac{E_b}{I_0}\right)}_{\mathrm{BS}}\·R\·\mathrm{RSSI}}{P_{r\_\mathrm{loss}}\·W}............\left(4\right)$ Calculate.

In the formula (4),

Be that the base station side demodulation is desired, the information bit bit energy that above-mentioned travelling carriage must satisfy in order to satisfy quality of service requirement and the ratio of disturbance spectrum density;

R is professional information rate;

RSSI is the reverse link signal overall strength, is recorded by the base station;

P _{R_loss}Be reverse path decline, similar with reverse open loop power control, can be with the forward path P that declines _{F_loss}Estimate, i.e. P _{R_loss}≈ P _{F_loss}, and

$P_{f\_\mathrm{loss}}=P_{\mathrm{pilot}\_\mathrm{rec}}/P_{\mathrm{pilot}\_\mathrm{send}}=\frac{\left(\frac{E_c}{I_o}\right)\·I_o\·1.2288\·{10}^6(\mathrm{chip}/s)}{P_{\mathrm{pilot}\_\mathrm{send}}}\·\frac{R}{W}$

So formula (4) has:

$P_r=\frac{{\left(\frac{E_b}{I_o}\right)}_{\mathrm{BS}}\·R\·\mathrm{RSSI}}{P_{r\_\mathrm{loss}}\·W}\≈\frac{{\left(\frac{E_b}{I_o}\right)}_{\mathrm{BS}}\·P_{\mathrm{pilot}\_\mathrm{send}\·R}}{\left(\frac{E_c}{I_o}\right)\·I_o\·1.2288\·{10}^6(\mathrm{chip}/s)}\·\frac{\mathrm{RSSI}}{W}\·\frac{R}{W}.$

In the soft switching process, travelling carriage can detect the pilot tone of a plurality of intensity greater than Active Set adding thresholding T_ADD, and deterministic process is asked for an interview following table 1 and table 2 signal:

Table 1

E c/I o(dB)	-18	-16	-14	-12	-10	-8
								36	32	28	24	20	16
P send	2.63	1.66	1.05	0.66	0.42	0.26

Table 2

Table 1 is one group of respective value of pilot frequency intensity that forward direction Initial Trans and travelling carriage receive, wherein,

Get P _Pilot=3 watts,

${\left(\frac{E_b}{I_o}\right)}_{\mathrm{mobile}}=4\mathrm{dB},$

$D={10}^{{(E_b/I_o)}_{\mathrm{mobiie}}/10}=2.5$

$M=-20\·\log \left(\frac{E_c}{I_o}\right)=-2\·\left(\frac{E_c}{I_o}\right)\mathrm{dB},\frac{W}{R}=128$

$P_{\mathrm{send}}=P_{\mathrm{pilot}}\·10\frac{D+0.5M}{10}\·\frac{R}{W}$

Table 2 is one group of respective value of the reverse link signal overall strength RSSI that records of back emitted power and base station, wherein,

Get P _{Pilot_semd}=3 watts, $\left(\frac{E_b}{I_o}\right)\mathrm{BS}=7\mathrm{dB},$ $\frac{E_c}{I_o}=-13\mathrm{dB},$ R＝9.6kbits/s

$P_r=\frac{{\left(\frac{E_b}{I_o}\right)}_{\mathrm{BS}}\·R\·\mathrm{RSSI}}{P_{r\_\mathrm{loss}}\·W}\≈\frac{{\left(\frac{E_b}{I_o}\right)}_{\mathrm{BS}}\·P_{\mathrm{piot}\_\mathrm{send}}\·R}{\left(\frac{E_c}{I_o}\right)\·I_o\·1.2288\·{10}^6(\mathrm{chip}/s)}\·\frac{\mathrm{RSSI}}{W}\·\frac{R}{W}---W=1.23\mathrm{Mbits}/s,$

Table 1, table 2 correspond respectively to each E _c/ I _o, under the reverse load value, required preceding, reverse Initial Trans numerical tabular (supposing that business is the data service of a fixed rate).As can be seen from Table 2 during same pilot intensity, the transmitting power of travelling carriage under the different reverse loads has reflected that relatively poor pilot frequency intensity and heavier reverse load are respectively to the influence degree of systematic function.

Corresponding to different reception pilot frequency intensities, forward direction Initial Trans difference for reducing the increase to the forward direction load, should be selected for use to receive the bigger sub-district of pilot frequency intensity as shown in Table 1.

Corresponding to different reverse signal overall strengths, back emitted power difference for reducing the increase to reverse load, should be selected the less sub-district of reverse signal overall strength for use when oppositely decline is identical as shown in Table 2.

Because preceding back emitted power is relatively independent, for the influence of overall merit to system, has adopted the method for weighted sum, that is:

$\mathrm{Es}=\frac{\mathrm{\α}}{P_f/P_{f\_\max }}+\frac{\mathrm{\β}}{P_r/P_r\_\max }$

E wherein _sBe the systematic function preferred value of obtaining, the cell selecting when carrying out soft handover by this value, preferred this value is set up soft handover branches than higher sub-district.P _fBe the forward direction Initial Trans, promptly the required transmitting power in base station supposes it is under the condition of desirable power control here.Pr is a back emitted power, i.e. the required transmitting power of travelling carriage.P _{F_max}Be that forward direction is to the maximum transmission power that unique user distributes, when getting system's full load herein and being the basic rate business, so P _{F_max}Can roughly be taken as 1 watt; P _{R_max}Be reverse maximum transmission power, generally be taken as 20 milliwatts.α is positive weights, and the reflection forward emitting power is to the influence of systematic function, and β also is positive weights, and reflection back emitted power is to the influence of systematic function.Get α=0.6 herein, β=0.4, these two weights can require to adjust according to the difference of system's practical business to preceding reverse capacity.

Following table 3 is to take all factors into consideration forward direction With under the influence of reverse RSSI to the selection of sub-district

Table 3

The district		Transmitting power (watt)	Degree (RSSI) (milliwatt)	Power (milliwatt)	Preferred value	The result
							A	-16	1.66	5×10 -9	15	0.89	Do not select
B	-14	1.05	1.59×10 -6	18	1.02	Select

RSSI calculates reverse Initial Trans according to the reverse link signal overall strength, fairly simple estimation the stationary value of back emitted power because the reverse attenuation amount can't obtain, be to adopt the forward direction attenuation to estimate, so estimated value and actual value have certain deviation.

Soft handover method of the present invention adopts existing C DMA2000 air interface protocol and corresponding construction, and this method is convenient to realize and calculates the not obviously increase of used time that the existing CDMA2000 system of parameters needed and hardware can provide.The mapping table 1-table 3 proof institute that draws through numerical computations based on thought be rational, than traditional changing method, it can improve systematic function effectively.By top description, those skilled in the art is not difficult to realize this soft switching subzone selection in conjunction with reverse load in the CDMA2000 system.

Claims (7)

1, soft switching subzone of mobile station method in a kind of code division multiple address communication system, this method is based on code division multiple access system, in this system, comprise a base station controller, several base station transceivers by this base station controller control, to the reverse link of the base station transceiver that activates with by the forward link of the base station transceiver that activates to travelling carriage, travelling carriage and each base station transceiver include a transreceiver, it is characterized in that this method may further comprise the steps by travelling carriage:

A makes at least one base station transceiver in travelling carriage and this system set up Traffic Channel, and travelling carriage is periodically searched for the pilot tone of using each base station transceiver on the frequency;

B, base station controller be according to the pilot tone number in the travelling carriage pilot tone Active Set, determines that Active Set adds thresholding or Active Set dynamically adds thresholding, and Active Set is added thresholding or Active Set dynamically add thresholding and be handed down to travelling carriage;

C, the pilot frequency intensity of each base station transceiver of travelling carriage continuous detecting also reports base station controller;

D, base station controller is judged the pilot tone number in the current Active Set of travelling carriage and judged result is handed down to travelling carriage and relevant base station transceiver by forward link;

E, the low sub-district of base station controller selective system performance preferred value Es is rejected in the Active Set and maybe will not be entered, again by the pilot tone assignment message with the cell notification travelling carriage of choosing, travelling carriage is according to the instruction foundation of base station controller and being connected of new sub-district, return step a after being finished again, wherein, described systematic function preferred value Es and forward link interference, return link interferences and range attenuation negative correlation;

F, above step cycle is carried out, till travelling carriage winding-up state.

2, soft switching subzone of mobile station method in the code division multiple address communication system as claimed in claim 1, it is characterized in that: among the described step b, if when having only a pilot tone in the travelling carriage pilot tone Active Set, then base station controller issues Active Set adding thresholding T_ADD and gives travelling carriage; If when an above pilot tone was arranged in the travelling carriage pilot tone Active Set, then base station controller issued Active Set dynamic threshold T_ADD_DYC and gives travelling carriage.

3, soft switching subzone of mobile station method in the code division multiple address communication system as claimed in claim 2 is characterized in that: described Active Set adds thresholding T_ADD value by default, generally gets-13db; Described Active Set dynamically adds thresholding T_ADD_DYC value according to formula

Obtain,

Wherein T_ADD_DYC is that Active Set dynamically adds thresholding, SOFT_SLOPEs is the dynamic slope that Active Set adds thresholding, Psi is the forward pilot intensity of I base station, and ADD_INTERCEPTs is the dynamic intercept that Active Set adds thresholding, and T_ADD is that Active Set adds thresholding.

4, soft switching subzone of mobile station method in the code division multiple address communication system as claimed in claim 1, it is characterized in that: among the described step c, the pilot frequency intensity of each base station transceiver of travelling carriage continuous detecting also reports base station controller and is meant when finding to have pilot frequency intensity to add thresholding T_ADD or Active Set when dynamically adding the pilot tone of thresholding T_ADD_DYC greater than Active Set, by pilot strength measurement report message this pilot tone is reported base station controller.

5, soft switching subzone of mobile station method in the code division multiple address communication system as claimed in claim 1, it is characterized in that: in the described steps d, when base station controller is judged the pilot tone number in the current Active Set of travelling carriage, if the pilot tone number less than 3 o'clock, then directly adds new pilot tone in the Active Set; If the pilot tone number is more than or equal to 3 o'clock, then according to formula

$\mathrm{Es}=\frac{\mathrm{\α}}{P_f/P_{f\_\max }}+\frac{\mathrm{\β}}{P_r/P_r\_\max }$

Calculate the pilot tone in the current Active Set and the systematic function preferred value Es of new pilot tone, wherein, P _fBe the forward direction Initial Trans, P _rBe reverse Initial Trans, P _{F_max}Be the maximum transmission power that forward direction distributes to unique user, P _{R_max}It is the maximum transmission power that oppositely distributes to unique user, α is positive weights, the reflection forward emitting power is to the influence of systematic function, β also is positive weights, and reflection back emitted power is selected the minimum pilot tone of preferred value to the influence of systematic function, if this pilot tone is in the current Active Set, then delete from Active Set, if this pilot tone is new pilot tone, then refusal adds Active Set.

6, soft switching subzone of mobile station method in the code division multiple address communication system as claimed in claim 5 is characterized in that: described formula $\mathrm{Es}=\frac{\mathrm{\α}}{P_f/P_{f\_\max }}+\frac{\mathrm{\β}}{P_r/P_r\_\max }$ In, the forward direction Initial Trans Pf of travelling carriage appointment is according to formula

$P_f=\min [P_{\mathrm{pilot}\_\mathrm{send}}\·10\frac{D+0.5M}{10}\·\frac{R}{W,}{P}_{\max }]$ Calculate, wherein, P _{Pilot_send}Be the forward pilot intensity of base station, D is the desired base station of the above-mentioned mobile station side demodulation information bit bit energy that must satisfy and the ratio of disturbance spectrum density, and M is the content of the above-mentioned forward pilot intensity item that obtains, and R is professional information rate, P _MaxBe the operable maximum power of travelling carriage, W=1.23Mbit/s.

7, soft switching subzone of mobile station method in the code division multiple address communication system as claimed in claim 5 is characterized in that: described formula $\mathrm{Es}=\frac{\mathrm{\α}}{P_f/P_{f\_\max }}+\frac{\mathrm{\β}}{P_r/P_r\_\max }$ In, oppositely Initial Trans Pr is according to formula $P_r=\frac{{\left(\frac{E_b}{I_0}\right)}_{\mathrm{BS}}\·R\·\mathrm{RSSI}}{P_{r\_\mathrm{loss}}\·W}$ Calculate, wherein,

Be the information bit bit energy and the ratio of disturbance spectrum density that the desired above-mentioned travelling carriage of base station side demodulation must satisfy in order to satisfy quality of service requirement, R is the information rate of business, and RSSI is the reverse link signal overall strength, P _{R_loss}It is the reverse path decline.

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