Spillage in Indoor Cells

For low throughput in Level P and Level2 C, Can we check the values for parameter of all the serving cells Cell Individual Offset, IntraRelThdFor1A, IntraRelThdFor1B, TrigTime1A,TrigTime1B, Hystfor1A, Hystfor1B and compare with the default valuesHystfor1AIf this parameter is set to a greater value, the coverage area where a soft handover can be performed reduces, for an incoming UE. However, the coverage area for an outgoing UE enlarges. If the UEs which enter the area are equal to those who leave the area, the ratio of SHOs remains unchanged. If this parameter is set to a greater value, the ability of resisting signal fluctuation improves and the number of ping-pong handovers decreases. However, the handover algorithm becomes slow in responding to the signal change.

This parameter specifies the hysteretic value for event 1A. For details on the definition of event 1A, see 3GPP TS 25.331. Event 1A, as a key event, refers to the event triggered when a cell is added to the active set. To ensure that the handover is triggered timely, the hysteresis for event 1A should be smaller than the hysteresis used for events 1B, 1F, 1C, and 1D. A too large difference between the hysteresis values affects the ratio of soft handovers (SHOs). In addition, filter coefficient and trigger delay must be considered in setting this parameter. The value of this parameter is associated with slow fading. If this parameter is set to a large value, the possibility of ping-pong handovers and incorrect handover decisions decreases but events cannot be triggered timely.

Hystfor1BThis parameter specifies the hysteretic value for event 1B. The value of this parameter is associated with the slow fading, and it can be used to reduce ping-pong handovers and incorrect handovers. For details on the definition of this parameter, see 3GPP TS 25.331.In addition, filter coefficient and interval time must be considered in setting this parameter.If this parameter is set to a greater value, the coverage area where a soft handover can be performed reduces, for an incoming UE. However, the coverage area for an outgoing UE enlarges. If the UEs which enter the area are equal to those who leave the area, the ratio of SHOs remains unchanged. If this parameter is set to a greater value, the ability of resisting signal fluctuation improves and the number of ping-pong handovers decreases. However, the handover algorithm becomes slow in responding to the signal change.

CIOThe larger the sum, the higher the handover priority of the neighboring cell. The smaller the sum, the lower the handover priority of the neighboring cell. Usually it is configured to 0. The larger the parameter, the easier of the handover to the neighboring cell. The smaller the parameter, the harder the handover to the neighboring cell.

IntraRelThdFor1ACSNVPRelative threshold for event 1A decision when non-VP service is performed in CS domain. If this parameter is set to a greater value, the probability of triggering event 1A increases. If this parameter is set to a smaller value, the probability of triggering event 1A reduces. For details on the definition of event 1A, see 3GPP TS 25.331.The relative threshold can directly affect the SHO ratio. Therefore, the threshold should be wisely chosen to achieve smooth SHOs. The value of this parameter determines the SHO area and SHO ratio. In the CDMA system, the ratio of the UE involved in soft handover should reach 30% to 40% to ensure smooth handover. Based on simulation results, when the relative threshold is set to 5 dB, the ratio of the UE involved in soft handover (the number of cells in the active set is at least 2) is about 35%. you are advised to set the relative threshold to a great value (5 dB to 7 dB) during site deployment, and to reduce the threshold when the users increase. the threshold must be higher than 3 dB to avoid the ping-pong handover. You can set different relative thresholds for event 1A and event 1B to reduce the ping-pong effect and change the soft handover ratio. In general applications, the relative thresholds for events 1A and 1B should be consistent, and you can curb the ping-pong effect through the triggering delay, L3 filtering coefficient, and hysteresis. In some specific applications, if the ping-pong effect cannot be curbed by adjusting the hysteresis values for event 1A and event 1B, you can curb it by setting a higher relative threshold for event 1B and a lower threshold for event 1A.

this parameter is set to a greater value, the probability of adding a cell to the active set increases. In this case, more UEs are in soft handover status; however, more forward resources are occupied. If this parameter is set to a smaller value, the probability of adding a cell to the active set reduces. Under this situation, the communication quality cannot be guaranteed, and smooth handover will be affected.

("IntraRelThdFor1ACSNVP" - "Hystfor1A" / 2) < ("IntraRelThdFor1BCSNVP" + "Hystfor1B" / 2).

IntraRelThdFor1BCSNVPRelative threshold for event 1B decision when non-VP service is performed in CS domain. If this parameter is set to a smaller value, the probability of triggering event 1B increases. If this parameter is set to a greater value, the probability of triggering event 1B reduces. For details on the definition of event 1B, see 3GPP TS 25.331. The relative threshold can directly affect the SHO ratio. Therefore, the threshold should be wisely chosen to achieve smooth SHOs. The value of this parameter determines the SHO area and SHO ratio. In the CDMA system, the ratio of the UE involved in soft handover should reach 30% to 40% to ensure smooth handover. Based on simulation results, when the relative threshold is set to 5 dB, the ratio of the UE involved in soft handover (the number of cells in the active set is at least 2) is about 35%. You are advised to set the relative threshold to a great value (5 dB to 7 dB) during site deployment, and to reduce the threshold when the users increase. the threshold must be higher than 3 dB to avoid the ping-pong handover. You can set different relative thresholds for event 1A and event 1B to reduce the ping-pong effect and change the soft handover ratio. In general applications, the relative thresholds for events 1A and 1B should be consistent, and you can curb the ping-pong effect through the triggering delay, L3 filtering coefficient, and hysteresis. In some specific applications, if the ping-pong effect cannot be curbed by adjusting the hysteresis values for event 1A and event 1B, you can curb it by setting a higher relative threshold for event 1B and a lower threshold for event 1A.

If this parameter is set to a greater value, the probability of adding a cell to the active set increases. In this case, more UEs are in soft handover status; however, more forward resources are occupied. If this parameter is set to a smaller value, the probability of adding a cell to the active set reduces. Under this situation, the communication quality cannot be guaranteed, and smooth handover will be affected.

TrigTime1AThis parameter specifies the interval time between detection of event 1A and sending of the measurement report. The value of this parameter is associated with slow fading. If this parameter is set to a greater value, the probability of incorrect decision becomes low; however, the handover algorithm becomes slow in responding to signal change. The time-to-trigger mechanism is introduced for the following purposes: - reducing the number of wrong event reports caused by burst signals, - preventing the ping-pong handover, - reducing the impact of shadow fading on event decisions. Setting an appropriate triggering delay effectively reduces the average number of handovers and the number of wrong handovers, preventing unnecessary handovers. If the handover cannot be triggered in time, the time-to-trigger parameter for event 1A needs to be changed to 200 ms or 100 ms, and the delay for event 1B needs to be changed to 1280 ms or 2560 ms.

If this parameter is set to a greater value, the average number of handovers decreases, but call drops may occur. If this parameter value set to a smaller value, handovers can be triggered timely, therefore reducing the call drop rate. According to TS 25.133 V3.6.0, intra-frequency measurement physical layer updates the measurement result once every 200 ms. Therefore, the time-to-trigger mechanism is invalid if the interval is shorter than 200 ms. The time-to-trigger interval should be close to a multiple of 200 ms. For details, see 3GPP TS 25.133. In addition, the UE at different rates may react differently to the same interval. For the fast-moving UE, the call drop rate is more sensitive to the interval, whereas, for the slow-moving UE, the call drop rate is less sensitive to the interval. Slow moving can also reduce ping-pong handovers and incorrect handovers. Therefore, for the cell where most UEs are in fast movement, this parameter can be set to a smaller value than its default value, whereas for the cell where most UEs are in slow movement, this parameter can be set to a greater value than its default value. In addition, different events require different values of the time-to-trigger parameter: the event of adding cells to the active set (event 1A) requires a smaller value of the time-to-trigger parameter; the events of replacing cells in the active set (events 1C and 1D) require fewer ping-pong and incorrect handovers and have no great impact on the call drop rate, and therefore the time-to-trigger parameter can be set to a great value; the events of deleting cells in the active set (events 1B and 1F) require fewer ping-pong handovers, and thus the time-to-trigger parameter can be adjusted, based on the actual network statistics. If the interval for event 1A is shortened, handovers can be triggered timely, thus reducing the call drop rate. If the interval for event 1B is prolonged, the average number of handovers and number of ping-pong handovers decrease, thus reducing the call drop rate. These adjustments, however, may cause the growth of the SHO ratio and the over use of the forward resources.

TrigTime1BThis parameter specifies the interval time between detection of event 1B and sending of the measurement report. The value of this parameter is associated with slow fading. If this parameter is set to a greater value, the probability of incorrect decision becomes low; however, the handover algorithm becomes slow in responding to signal change. The time-to-trigger mechanism is introduced for the following purposes: - reducing the number of wrong event reports caused by burst signals, - preventing the ping-pong handover, - reducing the impact of shadow fading on event decisions. Setting an appropriate interval time effectively reduces the average number of handovers and the number of wrong handovers, preventing unnecessary handovers. If the handover cannot be triggered in time, the time-to-trigger parameter for event 1A needs to be changed to 200 ms or 100 ms, and the delay for event 1B needs to be changed to 1280 ms or 2560 ms.

this parameter is set to a greater value, the average number of handovers decreases, but call drops may occur. If this parameter is set to a smaller value, handovers can be triggered timely, therefore reducing the call drop rate. According to TS 25.133 V3.6.0, intra-frequency measurement physical layer updates the measurement result once every 200 ms. Therefore, the time-to-trigger mechanism is invalid if the interval is shorter than 200 ms. The time-to-trigger interval should be close to a multiple of 200 ms. For details, see 3GPP TS 25.133. In addition, the UE at different rates may react differently to the same interval. For the fast-moving UE, the call drop rate is more sensitive to the interval, whereas, for the slow-moving UE, the call drop rate is less sensitive to the interval. Slow moving can also reduce ping-pong handovers and incorrect handovers. Therefore, for the cell where most UEs are in fast movement, this parameter can be set to a smaller value than its default value, whereas for the cell where most UEs are in slow movement, this parameter can be set to a greater value than its default value. In addition, different events require different values of the time-to-trigger parameter: the event of adding cells to the active set (event 1A) requires a smaller value of the time-to-trigger parameter; the events of replacing cells in the active set (events 1C and 1D) require fewer ping-pong and incorrect handovers and have no great impact on the call drop rate, and therefore the time-to-trigger parameter can be set to a great value; the events of deleting cells in the active set (events 1B and 1F) require fewer ping-pong handovers, and thus the time-to-trigger parameter can be adjusted, based on the actual network statistics. It is advised to set the time-to-trigger parameter for different events in a macro cell to a value from the following ranges: \Table 1. Typical time-to-trigger interval for events 1B or 1F on various channels At the speed of 5 (km/h): the range is 640~1280 (ms), it is advise to set the time-to-trigger parameter to 1280 (ms). At the speed of 50 (km/h): the range is 240~640 (ms), it is advise to set the time-to-trigger parameter to 640 (ms). At the speed of 120 (km/h): the range is 240~640 (ms), it is advise to set the time-to-trigger parameter to 640 (ms). Typical configuration of the time-to-trigger parameter for events 1B or 1F: the range is 640~1280 (ms), it is advised to set the parameter to 640 (ms). In a micro cell, the time-to-trigger parameter for different events should be shortened as required. If the interval for event 1A is shortened, handovers can be triggered timely, thus reducing the call drop rate. If the interval for event 1B is prolonged, the average number of handovers and number of ping-pong handovers decrease, thus reducing the call drop rate. These adjustments, however, may cause the growth of the SHO ratio and the over use of the forward resources.

MNew is the measurement value of the cell in the reporting range. CIONew is equal to the sum of Cell oriented Cell Individual Offset and Neighboring cell oriented CIO, which is the offset between the cell in the reporting range and the best cell in the active set. MBest is the measurement value of the best cell in the active set. R1A is the reporting range or the relative threshold of soft handover. The threshold parameters of the CS non-VP service, VP service, and PS service are as follows: CS non VP service 1A event relative THD VP service 1A event relative THD PS service 1A event relative threshold H1A represents 1A hysteresis, the hysteresis value of event 1A. The case for 1A event report

CIO (cell individual offset) Source cell in SRNC, Target cell in SRNC CIO of target cell = CIO (i.e. Cell oriented Cell Individual Offset) + CIOOffset (i.e. Neighboring cell oriented CIO ) MML: set CIO through ADD/MOD CELLSETUP, set CIOoffset through ADD/MOD INTRAFREQNCELL or ADD/MOD INTERFREQNCELL Source cell in SRNC, Target cell is GSM cell CIO of target cell = CIO (i.e. Cell oriented Cell Individual Offset) + CIOOffset (i.e. Neighboring cell oriented CIO ) MML: set CIO through ADD/MOD GSMCELL, set CIOoffset through ADD/MOD GSMNCELL

Cell oriented Cell Individual Offset Parameter ID: CIO Value range: -10 to +10 Content: This parameter is used together with Neighboring cell oriented CIO. The sum of the two parameter values is added to the measurement quantity before the UE evaluates whether an event occurred. In handover algorithms, this parameter is used for moving the border of a cell. The recommended value of this parameter is 0 ( 0dB ) Set this parameter through ADD CELLSETUP / MOD CELLSETUP Neighboring cell oriented CIO Parameter ID: CIOOffset Value range: -10 to +10 Content: This parameter is used together with Cell oriented Cell Individual Offset. The sum of the two parameter values is added to the measurement quantity before the UE evaluates whether an event has occurred. In handover algorithms, this parameter is used for moving the border of 2 neighbors. The recommended value of this parameter is 0 ( 0dB ) Set this parameter through ADD INTRAFREQNCELL / MOD INTRAFREQNCELL Source cell in SRNC, Target cell in DRNC CIO of target cell = CIO (i.e. Cell oriented Cell Individual Offset) + CIOOffset (i.e. Neighboring cell oriented CIO ) MML: set CIO through ADD/MOD NRNCCELL, set CIOoffset through ADD/MOD INTRAFREQNCELL or ADD/MOD INTERFREQNCELL Target cell in DRNC SRNC can get CIO of target cell through RNSAP_RL_SETUP_RSP / RNSAP_RL_ADD_RSP from DRNC

1A Event Report Mode: Event Trigger Report Event to Periodical Report The parameters for 1A Event to Periodical Report 1A event to periodical report period 1A event to periodical report number The report mode of 1A is Event Trigger Report . Generally the event 1A is triggered by event only once. However, to avoid measurement report loss, the event 1A reporting can be turned to periodical reporting. 1A event to periodical rpt period Parameter ID: ReportIntervalfor1A Value range: NON_PERIODIC_REPORT, D250, D500, D1000, D2000, D4000, D8000, D16000 Content: The reporting period for the event 1A. Generally the event 1A is reported only once. However, to avoid measurement report loss, the event 1A reporting can be turned to periodical reporting. The default value of this parameter is D4000 (4000 ms) 1A event to periodical rpt number Parameter ID: PeriodMRReportNumfor1A Value range: D1, D2, D4, D8, D16, D32, D64, infinity Content: The periodical reporting times for the event 1A. When the actual times exceed this parameter, the periodical reporting comes to an end. The recommended value of this parameter is D16 Set above parameters through SET INTRAFREQHO / ADD CELLINTRAFREQHO / MOD CELLINTRAFREQHO

1B EVENT Event 1B is triggered on the basis of the following formula MOld is the measurement value of the cell that becomes worse. CIOOld is equal to the sum of Cell oriented Cell Individual Offset and Neighboring cell oriented CIO, which is the offset between the cell in the reporting range and the best cell in the active set. R1B is the reporting range or the relative threshold of soft handover. The threshold parameters of the CS non-VP service, VP service, and PS services are as follows: CS non VP service 1B event relative THD VP service 1B event relative THD PS service 1B event relative threshold H1B represents 1B hysteresis, the hysteresis value of event 1B. The case for 1B event reportParameters of 1B Event CS non VP service 1B event relative THD Parameter ID: IntraRelThdFor1BCSNVP Value range: 0~14.5; step: 0.5 Content: This parameter specifies the relative threshold of event 1B for the CS non-VP service. The smaller the parameter value is, the more easily event 1B is triggered . The default value of this parameter is 12 (6dB) VP service 1B event relative THD Parameter ID: IntraRelThdFor1BCSVP Value range: 0~14.5; step: 0.5 Content: This parameter specifies the relative threshold of event 1A for the VP service. The smaller the parameter value is, the more easily event 1B is triggered . The default value of this parameter is 12 (6dB) PS service 1A event relative THD Parameter ID: IntraRelThdFor1APS Value range: 0~14.5; step: 0.5 Content: This parameter specifies the PS service relative threshold of event 1A. The smaller the parameter value is, the more easily event 1B is triggered . The default value of this parameter is 12 (6dB) Notes : For the PS and CS combined services, the threshold for CS services is used. For the signaling connection of the UE, the threshold for CS services is used. 1B hysteresis Parameter ID: Hystfor1B Value range: 0~7.5; step: 0.5 Content: This parameter specifies the hysteresis value of event 1B. It is related to the slow fading characteristic. The default value of this parameter is 0 (0dB) 1B event trigger delay time Parameter ID: TrigTime1B Value range: 0, 10, 20, 40, 60, 80, 100, 120, 160, 200, 240, 320, 640, 1280, 2560, 5000 ms Content: This parameter specifies the trigger delay time of event 1B. It is related to the slow fading characteristic. The greater the parameter value, the smaller the probability of misjudgment, but the slower the response of event reporting, triggered by measured signal changes. The recommended value of this parameter is D640 ( 640ms ) Set above parameters through SET INTRAFREQHO / ADD CELLINTRAFREQHO / MOD CELLINTRAFREQHO

For Spillage control in indoor cell: Intra Relthd !A to reduce and IntraRelThd1B to be increased.Time to Trigg IB to be reduced for fast removal report request Time to trigger 1A to be increased

CIO to be positive or negative CIO positive is to enhance the handover to neigbour and negative CIO to reduce the handover to the neigbour the spilling cell will be the active set but not as primary cpichTrgtime 1A to be increases to delay the addition and Trig time IB to be reduced to enhance the removal of the cell

Pls chk the SHO attempt, add attempt and add success attempt before and after the change of the parameter.

To avoid pingpong handover the you have change the You can set different relative thresholds for event 1A and event 1B to reduce the ping-pong effect and change the soft handover ratio. In general applications, the relative thresholds for events 1A and 1B should be consistent, and you can curb the ping-pong effect through the triggering delay, L3 filtering coefficient, and hysteresis. In some specific applications, if the ping-pong effect cannot be curbed by adjusting the hysteresis values for event 1A and event 1B, you can curb it by setting a higher relative threshold for event 1B and a lower threshold for event 1A.

WCDMA dropped call analysis and solution yjnter June 30th, 2010 Abroad, WCDMA has already put into commercially a plurality of countries; In our country, WCDMA products are moving to maturity progressively, the step of commercialization of network is being accelerated. In networking and operation, cutting off rate (calldroprate) It is one of the important indexes which reflects network quality; The dropped call problem is a piece of Q&A faced in daily network optimization too. Basic procedure, various dropped call data analytical methods, ways to solve the problem of dropped call,etc. respect that this text deals with the definition of the dropped call, dropped call are studied, and combine the real dropped call case to analyze. First, definition of the dropped call 1.The dropped call of road measuring is defined The dropped call of road measuring is defined: Look from air interface signalling that UE side is recorded, in the conversation course (under connected state) China, if any that empty oral news meets 3 following conditions is regarded as the dropped call of road measuring. (1)Receive any broadcast channel news. (2)Receive the released news of Radio Resource RR and the released reason is abnormal. (3)The news of releasing etc. of receiving call control and breaking connecting, call control, and the released reason is abnormal. 2.The dropped call in interconnected system index is defined The broad cutting off rate should include the cuttings off rate of CN and UTRAN, because the cutting off rate index of the side with UTRAN of paying close attention that the network is excellent, this text cutting off rate describes KPI index of UTRAN side of paying close attention too. Say from the great respect, the dropped call is divided into two big classes, the signalling surface dropped call and dropped call of the User plane. The ones that need proving are: The definition of the interconnected system dropped call of radio network is counted only in terms of Iu interface, have counted the number of times of released request of abnormal resource that RNC initiates voluntarily; The dropped call of road measuring defines that mainly combines reason value to define with the news that is not entered floor from empty oral news, the two no perfect agreement. For example, as to carrying on the main incoming call at the same time, record the caller's air interface news with tool, if Called unusual dropped call, analyze the caller's procedure will be dropped call, but in view of interconnected system, this calling does not have dropped call index to record. So the definition of the two is not totally concerted, need to distinguish while analyzing. Second, dropped call case study Because dropped call analyze, involve concrete signalling, analyze so this text consult China go on and analyze for the parameter setting of the apparatus, the parameter definition of different apparatuses might not be the same, but the analytical method is communicating. 1.The vicinity leaks and mixes Generally speaking, the great majority are cause by the fact that it is worthy of that the vicinity leak in optimizing course initial stage in the dropped call. As to the co-frequency vicinity, usually confirm by following method whether to leak to match for the co-frequency vicinity. The first method: Active set EcIo information of UE record and BestServerEcIo information of the record before observing dropped call. If EcIo of UE record is very bad, and BestServer EcIo recorded is very good, in the vicinity tabulation of co-frequency measuring control whether the audit record Best Server EcIo scramble appears before the dropped call recently at the same time. If there are no scrambles in the vicinity tabulation of measuring control of co-frequency, can then confirm it is the vicinity that leaks and mixes. The method two: If UE reconnection at once after the dropped call, the scramble of Residential Area of UE reconnection is inconsistent with the scramble at the time of the dropped call, also can suspect it is the vicinity that leaks and mixes the issue, can further confirm through measuring control (begin with news of the position of dropped call to look for forward, find recently a piece of co-frequency measures control message, check this vicinity tabulation of measuring control message) . The method three: Some UE will appear in the newspaper and measure and collect (DetectedSet) Information, if the dropped call finds that there is corresponding scramble information while collecting information before taking place, also can confirm it is the vicinity that leaks the question mixed. The vicinity leaks the dropped call including pilot frequency vicinity that is worthy of causing leaks and mixes and the different systematic vicinity leaks and mixes. It is the same as nearly of co-frequency that the pilot frequency vicinity leaks the affirmation method mixed, it is mainly the time when dropped call takes place, the mobile phone has not measured or appeared in the newspaper the pilot frequency vicinity, but resident reaches to the pilot frequency vicinity again after the dropped call of the mobile phone. The different systematic vicinity leaks and worthy of being shown as the mobile phone in 3G network dropped call, the network to 2G of resident of network selecting again of the mobile phone after the dropped call, according to signal quality, the quality of 2G network is very good (some tests the mobile phone using 2G and observes RSSI signal in the dropped call) . 2.Cover difference Generally speaking, as to Voice, EcIo in CPICH greater than 14dB, RSCP greater than at the 100dBm (the measured value adopted) ,It can not be because of not covering the dropped call that causes and doing. Usually said cover difference mainly means RSCP is very bad. Table 1 OutdoorEcIo and Ec that require require plan, ' Come from the network planning of Hong Kong SUNDAY) . The up run is covered with difference and descented and covered with the bad problem to need confirming by the upstream or descending special channel power before the dropped call. Lack, stand, sector connect by mistake, result in, stand reason of closing etc. can result in, cover difference by the intersection of power amplifier and trouble, in some indoor, because too big penetration loss, too can result in, cover with too poor. The sector is connected by mistake or the site is easy to present in the course of optimizing to close and wait for because of trouble, the cover difference clicked in the dropped call in other Residential Areas that shown as, need paying attention to analyzing distinguish. 3.Switch over the dropped call caused Soft handover / co-frequency causes the dropped call to mainly have two kinds of reasons: It is too late to switch over or the table tennis is switched over. In view of signalling procedure, CS business show as mobile phone charge active set upgrade order (co-frequency when the hard handover for physical the intersection of signal channel and rearrangement) ,PS business too may charge active set upgrade order, take place first before switching over probably too TRB reset. Solve and switch over the dropped call too late to cause, can expand the switching section through adjusting the aerial, can dispose the intersection of 1a and the intersection of switch and parameter of incident, make it take place easily not to switch over, dispose CIO, enable the intersection of goal and Residential Area switch over ahead of time. Solve the table tennis and switch over the dropped call problem brought, can adjust the aerial to make the overlay area form the leading Residential Area, also the switch parameter that can dispose 1b incident reduces the table tennis method of emergence,etc. to switch over goes on. Switched over and intersystem and switches over as to pilot frequency, need to carry on pilot frequency or different systematic measurement by starting and compressing the mode before switching over. Compress mode start too late, may cause mobile phone to be too late to measure the intersection of goal and signal of Residential Area, thus produce dropped call, might mobile phone finish measurement too, pilot frequency that issue switch over and different systematic the intersection of Handover request and mobile phone can't receive and lead to the fact the dropped call normally. 4.Dropped call that the interference causes Descent and upstream interference will all cause the dropped call. Generally speaking, for descenting, collect as activating CPICHRSCP is greater than - 85dB, collects comprehensive EcIo and is smaller than in and activation - 13dB has produced the dropped call, question (when switching over in time of the interference that it can be regarded as descenting that basically, also perhaps the serving cell RSCP signal appears very good, EcIo is very bad but monitors and collects Residential Areas RSCP and EcIo at this moment all very good) ; As to upstream RTWP than normal value ' -107- -105)Exceed 10dB, interfering with time exceeds 2- 3s, may cause the dropped call, needs solving especially. Descent, interfere with usually guiding, polluting frequently, mean, cover area, have more than 3 Residential Area meet, switch over terms, because the fluctuation of the signal often replaces or changes in the optimum Residential Area the active set, look on the intersection of active set and kind overall quality (EcIo of CPICH fluctuate from side to side in 10dB) as usually ,It causes SRB to reset to switch over failing easily, may reset TRB too. The upstream interference has increased and connected the modal mobile phone upstream transmitted power, thus has produced high BLER has caused SRB, TRB to reset or because the loss of synchronism causes the dropped called. In addition, when switching over, the newly-built periodic line causes the periodic line and be unable to move ahead simultaneously because of the upstream interference, thus cause the switch success rate of this Residential Area to be low, or cause and switch over failing and causing the dropped call. 5.Dropped call that the apparatus question causes The dropped call that the apparatus defect causes includes the mobile phone supports reasons such as the cooperation of the respect, apparatus of radio network and mobile phone,etc.. This kind of question needs to analyze, there is no general processing method to particular procedure and mobile phone. Analyze the procedure in third, dropped call 1.Analyze the procedure in dropped call The data analysis procedure of the dropped call is shown as in Fig. 1. 2.Prepare the data The software of road measuring is gathered the data file, RNC records individual user's tracing, RNC records CDL. 3.Obtain the position of dropped call Adopt the data processing software of road measuring, for example: Time and place obtaining the dropped call with Analyzer, the pilot frequency data gathered before and after obtaining the dropped call, collect information in active set and monitoring that the mobile phone is gathered, signalling procedure,etc.. 4.Analyze the change of the leading Residential Area The variety situation of the leading Residential Area of main analysis, if the leading Residential Area is relatively stable, further analyze the situations of RSCP and EcIo; If change frequently in the leading Residential Area, need to distinguish the leading Residential Area and changing the quick situation. Without the situation of the leading Residential Area, then further carry on the table tennis and switch over the analysis of dropped call. 5.Analyze the leading signal RSCP and EcNo of Residential Area Observe the leading Residential Area RSCP and EcNo, deal with respectively according to different situations. RSCP is bad, EcNo is bad, can confirm as and cover the question. (get rid of, switch over too late to cause, co-frequency vicinity interfered with) ,Can confirm as the interference problem of pilot frequency; RSCP EcNo normal normal, if the intersection of UE and the intersection of activity and centralized Residential Area, until Residential Area inconsistent preferably, may vicinity leak, mix or switch over too late dropped call that lead to the fact; If the intersection of UE and the intersection of activity and centralized Residential Area with identical Residential Area preferably, might interfere with unusual dropped call for the up run. 6.Road measuring reproduces the question Because road measuring may not be sure to be gathered to and positioned all required information of dropped call question, data gathering needs to come through further road measuring at this moment. Can confirm too this dropped call is clicked but clicked or fixed the dropped call to click by random dropped call through further road measuring, fixed dropped call order, will certainly need, solve generally speaking, but random dropped call order, need, confirm, need, solve according to probability taking place in dropped call. Fourth, solution of the dropped call 1.The project parameter is adjusted The adjustment of the project parameter is very definite, the most fundamentally can adjust position, height, lobe width, antenna gain and steering angle of lower dip angles, aerials of aerial of the site,etc.. Or descent and cover with the dropped call that the question causes as to the up run, the site of increase is a preferably method, can consider changing the height of the aerial, lower dip angle at the same time, can change the more high aerial of the gain to noise temperature ratio or increase the tower to put too. As to pinpoint and corner effect, it is more valid solution to adjust the aerial, because pinpoint effect and corner effect often appear at the place where the street turns round or the places of two pieces of juncture of residential district, can consider staggering the way of certain angle to adjust through steering angle and street of the aerial, need, notice, can't make the intersection of street and the intersection of roadside and retail shop to very great influence covered originally at the same time. As to the cover question that the interference of pilot frequency causes, can pass the project parameter of adjusting a certain aerial, make this aerial interfere with the position and become the leading Residential Area; Also can be through adjusting some other aerial parameters, reduce the intensity that the signal reaches these districts to reduce the number of pilot frequency; If the condition permits, can increase the new base station and cover this area; If the interference comes from two sectors of a base station, can consider amalgamating the sector. The adjustment of the project parameter needs to consider the adjustment result of the whole Residential Area synthetically, should pay attention to not introducing the new problem while solving a problem in the area of others. Generally speaking, when it is inconvenient to frequently adjust the aerial and have ready conditions to carry on artificially, need to analyze the simulation result before and after adjustment; If condition does not carry on emulation, but convenient while adjusting the aerial many times, can adjust according to the experience and method to combine actual road measuring. 2.The parameter is adjusted (1)Bias in the Residential Area This value and actual measured value add the incident evaluation process that the resulting number value is used in UE. UE uses for the co-frequency of UE and switches over the judgement as the measuring result after adding this Residential Area of primitive measured values to this bias, play a role in moving the boundry of Residential Area in switching over algorithms. The greater this parameter setting is, then the easier soft handover is, the more UE in soft handover state is, take up the more resourceses; Set up the smaller, the more difficult soft handover is, may influence receiving quality. As to the pinpoint effect or corner effect, it is a better solution to dispose CIO about 5dB, but will bring and increase the side effect which switch over proportion,etc.. (2)Associated delay triggered time of soft handover It is the triggered time that 1A, 1B, 1C are correlated with 1D incident to delay triggered time, the disposition of triggered time will influence the timeliness switched over. Generally speaking, the disposition of the default parameter can meet the requirements of most scenes, but to some intensive urban areas, need through apt to join active set and concentrate on, delete such a way, come, switch over from activity too frequent too late to switch over and prevent the dropped call from while being difficult. Touch off the impact on proportion of switching section of the time allocation bigger, especially the adjustment of triggered time of 1B incident can control and switch over the proportion better. Switching over the parameter can be set up to the Residential Area, after presuming a set of basic parameters according to the environment, adjust alone to each Residential Area, can limit the influence that the parameter changes among several Residential Areas, the impact on system is minor too. (3)Dropped call solution of soft handover a.Adjust the aerial, make the aerial in the Residential Area of the goal cover and cross the corner, can switch over before the corner, or make the aerial in the Residential Area covering and crossing the corner at present, thus prevent the signal brought in corner from changing the course fast to reduce the dropped call. In actual implementation, because the adjustment of the project parameter of the aerial and judgement that can cross the corner depend on the experience too much, difficulty of making the implementation of this method sure. b.Dispose 1A incident parameter to the Residential Area, so as to switch over easier to touch off. For example, reduce triggered time as 200ms, it is sluggish to reduce; The general condition needs to carry on the disposition to the Residential Area, the change of this parameter will cause this Residential Area and other Residential Areas (the Residential Area without corner effect) Switch happening,may cause by too much table tennis switch. c.Formulate the corner effect and produce CIO between two Residential Areas, make the Residential Area of the goal easier to join. Because CIO only influences the switch behavior between two Residential Areas, influences the face to be relatively minor, but CIO will be to switching over and exerting an influence, this kind of disposition may result in switching over the increase of the proportion. Measure to synthesize the above, propose adopting a preferably, if a can't be solved, adopts the method b, in case of b unable problem solving finally, adopt the method c. Fifth, summarize The cause of the dropped call question is very complicated, need to carry on analysis carefully as to some local dropped call reasons, prevent from, confuse surface phenomena, could find out the basic reason of the problem thorough problem solving. Tags: wcdma