CN101287275A - Method for measuring interference of adjacent cell in downlink direction based on CDMA system - Google Patents

Abstract

The invention discloses a method for measuring the interference from adjacent cells in the downlink direction based on a CDMA system. The method of the invention comprises the steps that: 1) the RSSI of a carrier frequency where a target cell locates is obtained when UE is switched; 2) the transmission code power (TCP) of the base station of a source cell to the UE and the interference to the UE by other users of the cell are then obtained; 3) when the UE is switched to a target cell with the same frequency, the interference from the adjacent cells in the downlink direction to the UE is RSSI - the transmission code power (TCP) of the base station of the source cell to the UE - the interference to the UE by other users of the cell; 4) when the UE is switched to a target cell with the same frequency, the interference from the adjacent cells in the downlink direction to the UE is RSSI - the interference to the UE by other users of the cell. By adopting the method of the invention, the accuracy for measuring the interference from downlink adjacent cells of the CDMA system can be improved, thereby improving the accuracy for estimating the algorithm of downlink admission control and open-loop power control during the process that the UE is switched and also effectively improving the call completion ratio and the stability of the system.

Description

A kind of method of measurement of disturbing based on the adjacent cell in downlink direction of cdma system

Technical field

The present invention relates to wireless communication field, specifically relate to the method for measurement that adjacent cell in downlink direction disturbs in CDMA (Code DivisionMultiple Access, the code division multiple access) system.

Background technology

Cdma system is power and interference-limited system.When the user in the system too much and wireless environment comparatively abominable the time, can produce the situation of traffic overload, show as: up direction UE (User Equipment, subscriber equipment) the mutually soaring up separately emitted power of meeting between, total transmitting power of harmful competition base station between each UE of down direction; Cause the interference each other of whole system excessive and can't break through the power bottleneck again at last, all user Qos (Quality of Service, service quality) are serious to descend, and finally causes large batch of conversation loss.

Cdma system is in order to guarantee user's Qos, and prevention system traffic overload occurs and introduced the RRM strategy of admitting control or access control.The principle of admission control scheme can be brought how many interference increment and power increment to system after predicting new access exactly or switching subscriber access system, and unsafe those users occur by the system that might make after admitting the control thresholding to refuse those connecting systems.In addition, in the prior art open loop power control algorithm of cdma system also be according to the user insert preceding or switch before the initial uplink transmitting power of this area interference of being subjected at Target cell of UE and adjacent area Interference Estimation UE and Node B to the initial downlink transmitting power of UE, therefore obtain the suffered interference value of UE the Qos that guarantees the user had great importance.

Because CDMA FDD (Frequency Division Duplex, Frequency Division Duplexing (FDD)) system and CDMATDD (Time Division Duplex, time division duplex) system embody the limited unlimited feature of descending power.Therefore the admittance control or the access control of down direction seem particularly important.The admittance control of down direction or the principle of access control are exactly will be according to this area interference of current system and the situation of adjacent area interference, the power increment that can cause behind the prediction UE connecting system.

Down direction UE supports Interference Signal Code Power (ISCP for the CDMA-TDD system, Interference Signal Code Power), though this amount can be represented the interference that adjacent area interference and this sub-district can not be eliminated, but ISCP only refers to the interferometry of co-frequency cell, does not then support this measurement for alien frequencies.Switch for alien frequencies, the general way of industry is to adopt adjacent this specific factor to estimate the adjacent area interference at present.

Adjacent this specific factor is that a fixed proportion relation is arranged between hypothesis this area interference level and the adjacent area interference level.But situation that disturb the actual conditions adjacent area and user are apart from the position of base station, the quantity of adjacent community user, user's distribution all has substantial connection, especially for the CDMA-TDD system owing to adopted intelligent antenna technology, the adjacent area is disturbed and is also depended on the arrival bearing angular distribution of different user to the base station, therefore adopting adjacent this specific factor is an estimated value on the average meaning, can't be applicable to all scenes, must cause and admit control and the estimation of open loop power control algorithm to have, cause the erroneous judgement system that makes instability or loss capacity to occur than large deviation.

Summary of the invention

The purpose of this invention is to provide a kind of method of measurement that cdma system handoff procedure adjacent cell in downlink direction disturbs that is used for.To solve the inaccurate problem of measurement that exists in the prior art.

In order to address the above problem, general thought of the present invention is: with UTRA Carrier RSSI (Received Signal Strength Indicator, carrier wave received signal intensity indication) measured value RSSI deduct the base station to the useful signal of UE be TCP transmission code power and other users of this sub-district to its interference value, its result is disturbed as the adjacent cell in downlink direction that UE is subjected to.

UE supports RSSI in cdma system, RSSI represents all signal strength signal intensities that UE receives in nominated bandwidth, this amount is illustrated in the assigned timeslot in CDMA TDD system, in the bandwidth of filter definition by the received power of receiver pulse shaping, comprising thermal noise and the noise that produces by receiver.Yet implication like the representation class in the CDMAFDD system, difference is: time slot is not distinguished in this measurement in the CDMAFDD system.

Technical scheme of the present invention comprises the steps:

1) when switching, obtains UE the carrier wave received signal RSSI of strength indicator value of Target cell place carrier frequency;

2) obtain the TCP transmission code power of source cell base station, and other users of this sub-district are to the interference of UE to UE;

3) when UE switched to Target cell frequently, the adjacent cell in downlink direction of UE disturbed and is: the carrier wave received signal RSSI-of strength indicator value source cell base station is to TCP transmission code power-other users of this sub-district of UE interference value to UE;

4) when UE switches to the alien frequencies Target cell, the adjacent cell in downlink direction of UE disturbs and is: the carrier wave received signal RSSI-of strength indicator value other users of this sub-district are to the interference value of UE.

The described source cell base station of obtaining comprises following treatment step to the TCP transmission code power of UE:

Obtain the transmitting power P of cell-of-origin to UE _{Tx_org}, UE is at the path loss PL of this sub-district _Org

Source cell base station to the TCP transmission code power of UE is: the cell-of-origin is to the transmitting power P of UE _{Tx_org}/ UE is at the path loss PL of this sub-district _Org

Describedly obtain other users of this sub-district the interference value of UE comprised following treatment step:

Obtain the path loss PL of UE at Target cell _Dst, and the horizontal P of transmission carrier power of Target cell _{Total_dst}

Other users of this sub-district to the interference value of UE are: the horizontal P of transmission carrier power of Target cell _{Total_dst}/ UE is at the path loss PL of Target cell _Dst

When system adopts smart antenna, set the average inhibitor gamma of smart antenna to disturbing between this community user _Ra, γ _RaValue between 0 to 1, if do not adopt smart antenna then this factor value is 1.

Other users of this sub-district to the interference value of UE are: (the horizontal P of transmission carrier power of Target cell _{Total_dst}The average inhibitor gamma of * smart antenna to disturbing between this community user _Ra)/UE is at the path loss PL of Target cell _Dst

Preferably, the obtain manner of the carrier wave received signal RSSI of strength indicator value of Target cell place carrier frequency is in the described step 1): UE periodically reports the carrier wave received signal RSSI of strength indicator value of Target cell place carrier frequency, gets during switching to switch a preceding nearest value.

Preferably, the obtain manner of the carrier wave received signal RSSI of strength indicator value of Target cell place carrier frequency is in the described step 1): the carrier wave received signal RSSI of strength indicator value of place, measurement target sub-district carrier frequency during switching.

When the system of measuring is the CDMA-TDD system, need obtain the RSSI of each downlink business time slot in the carrier frequency of Target cell place.

Wherein, this sub-district of mentioning among the present invention is meant sub-district, the current place of UE.The sub-district at UE place before the cell-of-origin just is meant and switches, Target cell be meant UE switch finish after the sub-district at place.

Adopt the method for the invention to improve and measure the levels of precision that disturb the adjacent area, thereby also can improve the descending acceptance control in the handoff procedure and the estimation precision of open Loop Power control algorithm, can effectively improve the call completion ratio of system and the stability of enhanced system.

Below by embodiment also in conjunction with the accompanying drawings, the present invention is described in further detail.

Description of drawings

Fig. 1 is used for the schematic flow sheet of the method for measurement of cdma system handoff procedure adjacent cell in downlink direction interference for the present invention.

Embodiment

Embodiment one:

When the present invention is applied to the CDMA-FDD system, and when adopting smart antenna.With reference to accompanying drawing 1, the method for measurement that adjacent cell in downlink direction disturbs comprises the steps:

When 101) UE switches, UE reports with frequency handover measurement incident 1G or alien frequencies handover measurement incident 2A, carry the UTRA Carrier rssi measurement value RSSI of Target cell place carrier frequency simultaneously, perhaps UE periodically reports UTRA Carrier RSSI, RNC (Radio Network Controller, radio network controller) gets and switches the report that the previous cycle takes place.

102) UE is reported to the path loss PL of source cell base station _OrgWith path loss PL to target cell base station _Dst

103) RNC obtains source cell base station to UE transmitting power P _{Tx_org}With the horizontal P of Target cell transmission carrier power _{Total_dst}

104) RNC makes switch decision, judges that this switching is with frequency handover measurement incident 1G or alien frequencies handover measurement incident 2A.

105) turning to according to judged result determination procedure flow process; If, then change step 106 over to frequency handover measurement incident 1G; If alien frequencies handover measurement incident 2A then changes step 107 over to.

106) when switching to frequency handover measurement incident 1G, UE disturbs with expression formula (1) in the adjacent area that Target cell is subjected to and calculates:

$I_{\mathrm{other}\_\mathrm{dst}}=\mathrm{RSSI}-P_{\mathrm{tx}\_\mathrm{org}}\·\frac{1}{{\mathrm{PL}}_{\mathrm{org}}}-P_{\mathrm{total}\_\mathrm{dst}}\·\stackrel{\‾}{{\mathrm{\γ}}_{\mathrm{ra}}}\·\frac{1}{{\mathrm{PL}}_{\mathrm{dst}}}---\left(1\right)$

γ wherein _RaThe average inhibiting factor of expression smart antenna to disturbing between this community user, this parameter is one 0～1 a coefficient.

107) when switching to alien frequencies handover measurement incident 2A, UE disturbs with expression formula (2) in the adjacent area that Target cell is subjected to and calculates:

$I_{\mathrm{other}\_\mathrm{dst}}=\mathrm{RSSI}-P_{\mathrm{total}\_\mathrm{dst}}\·\stackrel{\‾}{{\mathrm{\γ}}_{\mathrm{ra}}}\·\frac{1}{{\mathrm{PL}}_{\mathrm{dst}}}---\left(2\right).$

Embodiment two:

When the present invention is applied to the CDMA-FDD system, and when not adopting smart antenna.Method of measurement and embodiment one that adjacent cell in downlink direction disturbs are similar, and difference is, the average inhibitor gamma of smart antenna to disturbing between this community user in step 106 and the step 107 _RaValue is 1.

Embodiment three:

When the present invention is applied to the CDMA-TDD system, and when adopting smart antenna.With reference to accompanying drawing 1, the method for measurement that adjacent cell in downlink direction disturbs comprises the steps:

When 101) UE switches, UE reports with frequency handover measurement incident 1G or alien frequencies handover measurement incident 2A, carry the UTRA Carrier rssi measurement value RSSI of each downlink business time slot place carrier frequency of Target cell simultaneously, perhaps UE periodically reports UTRA Carrier RSSI, and RNC gets and switches the report that the previous cycle takes place.

102) UE is reported to the path loss PL of source cell base station _OrgWith path loss PL to target cell base station _Dst

103) RNC obtains source cell base station to UE transmitting power P _{Tx_org}With the horizontal P of each business time-slot transmission carrier power of Target cell _{Total_dst}

104) RNC makes switch decision, judges that this switching is with frequency handover measurement incident 1G or alien frequencies handover measurement incident 2A.

105) turning to according to judged result determination procedure flow process; If then change step 106 over to frequency handover measurement incident 1G; If alien frequencies handover measurement incident 2A then changes step 107 over to.

106) when switching to frequency handover measurement incident 1G, UE disturbs with expression formula (1) in the adjacent area that Target cell is subjected to and calculates:

$I_{\mathrm{other}\_\mathrm{dst}}=\mathrm{RSSI}-P_{\mathrm{tx}\_\mathrm{org}}\·\frac{1}{{\mathrm{PL}}_{\mathrm{org}}}-P_{\mathrm{total}\_\mathrm{dst}}\·\stackrel{\‾}{{\mathrm{\γ}}_{\mathrm{ra}}}\·\frac{1}{{\mathrm{PL}}_{\mathrm{dst}}}---\left(1\right)$ γ wherein _RaThe average inhibiting factor of expression smart antenna to disturbing between this community user, this parameter is one 0～1 a coefficient.

107) when switching to alien frequencies handover measurement incident 2A, UE disturbs with expression formula (2) in the adjacent area that Target cell is subjected to and calculates: $I_{\mathrm{other}\_\mathrm{dst}}=\mathrm{RSSI}-P_{\mathrm{total}\_\mathrm{dst}}\·\stackrel{\‾}{{\mathrm{\γ}}_{\mathrm{ra}}}\·\frac{1}{{\mathrm{PL}}_{\mathrm{dst}}}---\left(2\right).$

Claims (7)

1. method of measurement of disturbing based on the adjacent cell in downlink direction of cdma system is characterized in that described method comprises following treatment step:

1) when switching, obtains UE the carrier wave received signal RSSI of strength indicator value of Target cell place carrier frequency;

2) obtain the TCP transmission code power of source cell base station, and obtain the interference value of other users of this sub-district UE to UE;

3) when UE switched to Target cell frequently, the adjacent cell in downlink direction of UE disturbed and is: the carrier wave received signal RSSI-of strength indicator value source cell base station is to TCP transmission code power-other users of this sub-district of UE interference value to UE;

4) when UE switches to the alien frequencies Target cell, the adjacent cell in downlink direction of UE disturbs and is: the carrier wave received signal RSSI-of strength indicator value other users of this sub-district are to the interference of UE.

2. the method for measurement that the adjacent cell in downlink direction based on cdma system according to claim 1 disturbs is characterized in that, the described source cell base station of obtaining comprises following treatment step to the TCP transmission code power of UE:

Obtain the transmitting power P of cell-of-origin to UE _{Tx_org}, UE is at the path loss PL of this sub-district _Org

Source cell base station to the TCP transmission code power of UE is: the cell-of-origin is to the transmitting power P of UE _{Tx_org}/ UE is at the path loss PL of this sub-district _Org

3. the method for measurement that the adjacent cell in downlink direction based on cdma system according to claim 1 disturbs is characterized in that, describedly obtains other users of this sub-district the interference value of UE is comprised following treatment step:

Obtain the path loss PL of UE at Target cell _Dst, and the horizontal P of transmission carrier power of Target cell _{Total_dst}

Other users of this sub-district to the interference value of UE are: the horizontal P of transmission carrier power of Target cell _{Total_dst}/ UE is at the path loss PL of Target cell _Dst

4. the method for measurement of disturbing based on the adjacent cell in downlink direction of cdma system according to claim 3 is characterized in that, when system adopts smart antenna, sets the average inhibitor gamma of smart antenna to disturbing between this community user _Ra, γ _RaValue between 0 to 1, other users of this sub-district to the interference of UE are: (the horizontal P of transmission carrier power of Target cell _{Total_dst}The average inhibitor gamma of * smart antenna to disturbing between this community user _Ra)/UE is at the path loss PL of Target cell _Dst

5. according to the arbitrary described method of measurement of disturbing based on the adjacent cell in downlink direction of cdma system of claim 1-4, it is characterized in that, the obtain manner of the carrier wave received signal RSSI of strength indicator value of Target cell place carrier frequency is in the described step 1): UE periodically reports the carrier wave received signal RSSI of strength indicator value of Target cell place carrier frequency, gets during switching to switch a preceding nearest value.

6. according to the arbitrary described method of measurement of disturbing based on the adjacent cell in downlink direction of cdma system of claim 1-4, it is characterized in that the obtain manner of the carrier wave received signal RSSI of strength indicator value of Target cell place carrier frequency is in the described step 1): the carrier wave received signal RSSI of strength indicator value of place, measurement target sub-district carrier frequency during switching.

7. according to the arbitrary described method of measurement of disturbing based on the adjacent cell in downlink direction of cdma system of claim 1-4, it is characterized in that,, obtain the RSSI of each downlink business time slot in the carrier frequency of Target cell place for the CDMA-TDD system.

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