WCDMA RNO Special Guide Coverage Problem AnalysisInternal open Document code Target readers Edited by WCDMA RNP Product name Product version Document version WCDMA RNP 2.0 1.0 WCDMA RNO Special Guide Coverage Problem Analysis (For internal use only) Drafted by: Reviewed by: Reviewed by: Approved by: WCDMA RNP Date: Date: Date: Date: November 21, 20004 Huawei Technologies Co., Ltd. All rights reserved 2005-07-13 All rights reserved Page 1 , Total36 WCDMA RNO Special Guide Coverage Problem Analysis Internal open Revision Records Date 2004-11-21 2005-02-28 Revised version 1.00 1.10 Description First draft completed Revision based on review comments Author Chen Qi Chen Qi 2005-07-13 All rights reserved Page 2 , Total36 WCDMA RNO Special Guide Coverage Problem Analysis Internal open Table of Contents 1 Overview of Coverage Analysis ................................................................................................................ 6 2 Coverage Problems Classifications ............................................................................................................ 6 2.1 Signal Dead Zone .................................................................................................................................. 6 2.2 Coverage Void ...................................................................................................................................... 7 2.3 Cross-cell Coverage .............................................................................................................................. 7 2.4 Pilot Pollution........................................................................................................................................ 8 2.5 Imbalance of Uplink and Downlink ...................................................................................................... 9 3 Coverage Analysis Flow .......................................................................................................................... 10 3.1 Preparations for related Knowledge .................................................................................................... 10 3.1.1 Planning Scheme .......................................................................................................................... 10 3.1.2 Analysis Tools .............................................................................................................................. 11 3.1.3 Configuration Parameters Adjustment .......................................................................................... 11 3.2 Coverage Data Analysis ...................................................................................................................... 13 3.2.1 Drive Test Data Analysis .............................................................................................................. 13 3.2.2 Traffic Measurement Data Analysis ............................................................................................. 21 3.2.3 Trace Data Analysis ...................................................................................................................... 21 3.2.4 User Complaints Analysis ............................................................................................................ 21 4 Coverage Enhancement Strategies ........................................................................................................... 21 4.1 NodeB Configuration Adjustment....................................................................................................... 21 4.2 Coverage Enhancement Technology ................................................................................................... 26 5 Typical Coverage Problems ..................................................................................................................... 27 5.1 Coverage Void due to Inappropriate Site Planning ............................................................................. 27 5.1.1 Problem Descriptions.................................................................................................................... 27 5.1.2 Analysis ........................................................................................................................................ 28 5.2 Cross-cell Coverage due to Inappropriate Site Selection .................................................................... 29 5.2.1 Problem Descriptions.................................................................................................................... 29 5.2.2 Analysis ........................................................................................................................................ 30 5.3 Coverage Restricted due to Irrational Antenna Installation ................................................................ 31 5.3.1 Problem Descriptions.................................................................................................................... 31 5.3.2 Analysis ........................................................................................................................................ 32 5.4 Coverage Restricted due to Antenna Installation Failure .................................................................... 33 5.4.1 Problem Descriptions.................................................................................................................... 33 5.4.2 Analysis ........................................................................................................................................ 33 6 Concerns at the Network Optimization Phases ........................................................................................ 34 6.1 Single Site Test Phase ......................................................................................................................... 34 6.2 Evaluation Phase before the Optimization .......................................................................................... 34 6.3 RF Optimization Phase........................................................................................................................ 34 6.4 Parameter Optimization Phase ............................................................................................................ 35 6.5 Network Optimization Project Acceptance Phase............................................................................... 35 7 Summary 35 2005-07-13 All rights reserved Page 3 , Total36 ....... 18 Figure 7 Abnormal UL RTWP recorded in the NodeB ............................................................................................................................................................. 14 Figure 2 Pilot Ec/Io Best Server distribution........... 20 Figure 9 UE transmit power distribution (macro-cellular) ................. 33 List of Figures Table 1 Huawei serial NodeBs and features (V100R003) ……………………………………21 2005-07-13 All rights reserved Page 4 . 31 Figure 15 Coverage restriction at the bottom of site without considering the shielding of platform 32 Figure 16 Optimization of antenna design implementation .................................................................................................. 28 Figure 11 Coverage prediction of XX pilot ................................... 16 Figure 5 Downlink code transmit power PDF of Voice service in the case of 50% load ...........WCDMA RNO Special Guide Coverage Problem Analysis Internal open List of Figures Figure 1 Pilot strength distribution ........................................................................................................................................................................................................................... 15 Figure 4 Comparison and analysis between the Scanner coverage and UE coverage ............................................................................................................................................................... 15 Figure 3 Pilot Ec/Io Best Server distribution..... 30 Figure 14 Cross-cell coverage after the optimization ................................................... 29 Figure 13 Cross-cell coverage before the optimization ............................................................................................................................................................................................................. Total36 ....................................................................... 20 Figure 10 Coverage void due to irrational site distribution ......................... 17 Figure 6 UE soft handover ratio ............... 33 Figure 17 Pilot RSCP coverage before and after the correction of antenna installation of 701640_ElzHse site.............. 19 Figure 8 UE transmit power distribution (micro-cellular) ......... 28 Figure 12 Site distribution ....... pilot pollution. and imbalance of uplink and downlink Abstract: This document instructs the network optimization engineers to analyze and solve the pilot coverage and service coverage problems that are present during the network optimization. cross-cell coverage. coverage void. Total36 . Acronyms and abbreviations: Acronyms Full spelling 2005-07-13 All rights reserved Page 5 . measure the network coverage performance and describes the coverage enhancement strategies.WCDMA RNO Special Guide Coverage Problem Analysis Internal open WCDMA RNO Coverage Problem Analysis Guide Key words: Signal dead zone. 2005-07-13 All rights reserved Page 6 . the engineering implementation must consider the interference. RSCP threshold is -115dBm. after the network planning and optimization. and the service coverage range of radio carrier is an important aspect of service quality. and Ec/Io threshold -18dB).27R (R is the cell radius) of overlapped coverage depth and the soft handover area and concern the same-neighbor frequency interference caused because the coverage range increases. tunnel. From the perspective of telecom operators. see the related documents. including from the site obtaining and antenna device indexes analysis to antenna type selection and propagation mode research from the pilot coverage and traffic distribution predication to static emulation and capacity analysis from the detailed design of engineering parameter and cell parameter to single site installation and test from the test route design and network performance test to system parameter adjustment optimization and KPI evaluation and the coverage analysis penetrates the whole process of network construction.WCDMA RNO Special Guide Coverage Problem Analysis Internal open 1 Overview of Coverage Analysis WCDMA radio network planning and optimization is a systematical project. the service quality provide by the network is the most concern. In addition. Analyzing and solving the problems found during the coverage verification of planning result is not involved in the document.1 Coverage Problems Classifications Signal Dead Zone The signal dead zone refers to the coverage area whose pilot signal is lower than the minimum access threshold of mobile phone (for example. the RF repeater may generate intermodulation interference. If there are many users in the non-overlapped coverage areas of two neighbor NodeBs or the non-overlapped coverage area is relatively larger. This document instructs the network optimization engineers to analyze and solve the pilot coverage and service coverage problems that are present during the network optimization and measure the network coverage performance. For details. Therefore. When the dead zone caused in the valley and the opposite of sideill is present. elevator well. Total36 . opposite of the sidehill. such as valley. add the NodeB or adopt the RRU or repeater to compensate effectively the dead zone and extension coverage range in the coverage areas. construct a new NodeB or add the coverage range of peripheral NodeBs (increase the pilot transmit power and antenna height at the risk of capacity) to ensure about 0. 2 2. underground garage or basement and inside of the high buildings. leakage cable. the transmission signal spreads far along with the hills or road and primary coverage is present in the coverage areas of other NodeBs to generate an “island”. For example. For example. and inside of high buildings is present. indoor distribution system. The pilot Ec/Io of network under certain load should not be lower than the minimum requirement for full-coverage service. where the mobile phone fails to camp on the cell and originates the location update and registration and the network drop is present. unideal site is inevitable.2 Coverage Void The coverage void refers to the coverage area whose pilot signal is lower than the minimum requirement of full-coverage services (such as Voice. During the network planning phase. In addition. repeater. the coverage void. but the pilot channel Ec/Io cannot satisfy the minimum requirement for full-coverage service because of intra-frequency interference increase. increase the antenna mounted height or reduce the mechanism tilt of antenna to optimize the coverage. the cell breathing effect generated due to the increase of the capacity of peripheral cells in the soft handover area results in the decrease of coverage quality in the soft handover areas. 2. 2. all the RSCPs of pilot signal in some areas can satisfy the requirement. When the coverage void is present. underground garage or basement. Out of the consideration of the restrictions of logistics and device installation. tunnel. when the traffic distribution is relatively balanced. or directional antenna. select the high gain antenna. If the RF adjustment does not effectively improve pilot Ec/Io coverage. the site distribution should be rational and an appropriate site can ensure that: The pilot RSCP strength of network is up to certain level (such as. VP and PS64K) but higher than the minimum access threshold of mobile phone. The coverage void is from the perspective of the mobile phone services. When access the “island” area far away from a 2005-07-13 All rights reserved Page 7 . that is. If the coverage void is not very critical.3 Cross-cell Coverage Cross-cell coverage means that the coverage areas of some NodeBs exceed the specified range but the primary areas without continuously satisfying the requirement of full-coverage service are generated in the coverage areas of other NodeBs.WCDMA RNO Special Guide Coverage Problem Analysis Internal open When the dead zone caused in the elevator well. the dense city: -65dBm and common city: -80dBm). no RSCP in some areas can satisfy the minimum requirement for full-coverage service due to the NodeB distribution imbalance. See two examples: For the sites excessively higher than mean height of peripheral buildings. Total36 . adopt the RRU. adjust the pilot power (increase the strongest power and reduce others) to generate the primary cell. different from the signal dead zone. construct a new micro-NodeB or repeater to strengthen the coverage. If there is a higher site. besides adjusting the layout and antenna parameter and reducing the pilot power. adjust the pilot power or use the electrical tilt antenna to reduce coverage range and eliminate the “island” effect. If necessary. the peripheral environment effect can summarized as the block to the signal from high buildings or mountains. The pilot pollution should be avoided at the planning 2005-07-13 All rights reserved Page 8 . Total36 . The pilot pollution is contributed to: Irrational cell layout Too high site or antenna mounted height Irrational setting of antenna direction angle Antenna back lobe effect Irrational setting of pilot power Peripheral environment effect Where. Meanwhile. For the areas at both sides of V Harbor. an effective method of reducing the cross-cell coverage is to change the site address. This document introduces the following method to judge whether the pilot pollution exists: There are more than three pilots satisfying the condition CPICH _ RSCP 95dBm and (CPICH _ RSCP1st CPICH _ RSCP4th ) 5dB Where. not immediate handover is easy to result in the call drop because the “island” area is over-small. and the excessive adjustment of mechanism tilt of antenna also distorts the antenna pattern. confirm whether the same-frequency interference to other NodeBs is generated. if there is no special design for the NodeBs at the Central and Coast of H Island.4 Pilot Pollution The pilot pollution means that too pilots are received in one point but there is no stronger primary pilot. Therefore. the interference to the useful signal is generated due to many strong pilots to increase Io and BLER. Owing to the restrictions of logistics and device installation. the call drop is present immediately if the mobile station moves out of the “island”. reduce Ec/Io and easily form the ping-pong handover resulting in call drop. Whatever the micro-cellular or macro-cellular coverage area. the absolute threshold judgement of pilot RSCP is to differentiate the coverage void and no primary cell at the target coverage cell edge. an appropriate site around the original site is unreachable. combining the NodeB sectors or deleting redundant sectors also can reduce the pilot pollution if the capacity is not affected. 2. To reduce the cross-cell coverage must avoid the antenna propagation directed to the road or uses the shield effect of peripheral buildings. if the pilot pollution is present.WCDMA RNO Special Guide Coverage Problem Analysis Internal open NodeB but served by the NodeB and the cells around the “island” are not set to the adjacent cells as setting the cell handover parameters. the cross-cell coverage is easily present to generate the interference because two sides of the harbor are too close. Even though the adjacent cells are configured. relatively far propagation extension of signal from the streets or the reflection of signal from high glass buildings. Total36 . For the imbalance of uplink and downlink generated by downlink power restriction. change the antenna installation location. but the inter-cell interference level and soft handover ratio must be controlled. The imbalance of uplink and downlink generated due to the uplink interference monitors RTWP alarms of NodeBs to detect the problems and checks antenna installation and adds antenna configuration to solve the problem. and the good pilot coverage is the precondition to guarantee service coverage quality. adopt the mounted amplifier to increase NodeB sensitivity under the condition of allowed downlink capacity loss. the uplink coverage restriction can be thought that the maximum transmit power of UE still cannot satisfy the receiver sensitivity requirement of NodeB. For example. If adopting the sectorization. For example. Theoretically.5 Imbalance of Uplink and Downlink The imbalance of uplink and downlink means the uplink coverage restriction (representing that the maximum transmit power of UE also cannot satisfy the uplink BLER requirement) or downlink coverage restriction (representing that the maximum transmit power of downlink dedicated channel code still cannot satisfy downlink BLER requirement) in the target coverage areas. See the examples: If 3G network shares the antenna with 2G network. the intermodulation interference and signal leakage generated by the cell edge or co-located device and inappropriate uplink gain setting of repeater generate the interference to NodeB RTWP uplink to increase the thermal noise and uplink coupling loss. For the interference from the repeater. adding the users increases local cell interference or adjacent cell interference and restricts the downlink power (such as the hybrid network of 10W power amplifier and 20W power amplifier causes the imbalance of radio resource configuration). The downlink coverage restriction can be thought as the increase of noise received by downlink mobile phone to deteriorate Ec/Io. or adopt sectorization. and partial areas must support asymmetrical service of discontinuous coverage (such as the service with 64K uplink and PS128K downlink and service with 64K uplink and PS384K downlink). add the carrier or construct a new cellular. or compare cell’s busy hour traffic volume with the calculated capacity to judge the traffic congestion. The most concern of telecom operators is the service coverage quality mapped to the traffic measurement indexes. add the band pass filter. check the congestion through the OMC traffic measurement data. the target areas must ensure the balance of uplink and downlink of continuous full-coverage service. For the uplink coverage restriction of cell edge. 2. 2005-07-13 All rights reserved Page 9 . Because WCDMA supports multi-service bearers.WCDMA RNO Special Guide Coverage Problem Analysis Internal open design phase to facilitate the later network optimization. the selected antenna type should be of narrow beam and high gain to increase the system capacity and improve the service coverage. The imbalance coverage of uplink and downlink easily generates call drop. antenna configuration. that is. coverage void. readjust the resource based on the network load. and type cannot use the pure coverage rule and must consider the capacity requirement and confirm the cellular structure type of target area from the perspective of redundancy cellular or capacity enhancement technology.1 Coverage Analysis Flow Preparation for related Knowledge Planning Scheme GSM planning scheme is based on the coverage range planning and frequency planning. Therefore. see the following: 1. terrain features. For details. 5. 3. NodeB configuration Understand the installed NodeB type. and cell primary scramble. cell transmit power. EIRP. signal dead zone. 2. NodeB configuration. the mapping between sector and cell. and tilt angle). Antenna configuration Understand the antenna type selection. 2005-07-13 All rights reserved Page 10 . and service load distribution. sector distribution. the network planning aims to improve the capacity requirement and frequency spectrum efficiency. the precondition of pilot coverage and reference service coverage analysis is to understand the planning scheme of target area. WCDMA has intra-frequency interference but no additional free of channel number allocated in TDMA system. Compared with GSM.1. uplink/downlink capacity distribution and restriction of each cell. In WCDMA. Pilot coverage prediction Understand the pilot coverage prediction result provided by the planning software and the service coverage in the areas based on the pilot coverage threshold of services. size. cell channel power configuration. soft handover area after the static emulation.1 3. which conform to respectively the coverage range rule and capacity rule obtained from the typical environment where earlier mobile communication system. and site type of each site in the area through the site survey report and obtain the site coverage target information. and antenna gain). 4. direction angle. The initial cellular design density. and cross-cell coverage. including sites distribution. pilot coverage prediction.WCDMA RNO Special Guide Coverage Problem Analysis Internal open 3 3. From the perspective of the resource allocation. and analyze whether the pilot pollution. height. Total36 . the succeeding parameter adjustment cannot solve the problem fundamentally. and antenna installation (antenna mounted height. antenna parameter (horizontal beamwidth. if the density of initial resource allocation cellular over the capacity restriction is irrational. Site distribution Obtain the surrounding clutter. site address. vertical beamwidth. Service load distribution Understand the reference traffic distribution. 2. analyzing whether the network cellular density fits the traffic distribution of users plays an important role.3 Configuration Parameters Adjustment The following lists the adjusted radio configuration parameters aiming to solve the coverage problems: 1. In the cell where the coverage is required. and check the signal coverage in a specific area through the replay similar to the foreground. and drive test coverage performance provided by the tools. 3. In general. After the network commercial use. We can refer to the auto analysis report of call event. TEMS also provides BAM analysis tools of data collected by the foreground.2 Analysis Tools The analysis of coverage data contains: Drive test call and the BAM of pilot census data Traffic measurement of current network UL RTWP alarm of each cell User call process traced by RNC Using proficiently the analysis tools helps to detect the network coverage problems and perform the planning and adjustment in combination with the planning tools. soft handover. Traffic measurement tools The traffic measurement analysis tools based on the traffic measurement point secondary development helps to grasp fast the traffic distribution and the cell performance indexes. Drive test BAM The common drive test data BAM analysis tools are Actix and Huawei Genex Assistant. Testability log Use RNC Debug Management System to analyze the testability log of records and the causes triggering the drop call of users. Setting the parameter should consider the actual system environment. such as cell coverage range (radius) and geographical environment. Total36 . 1. CPICH TX Power This parameter defines the transmit power of intra-cell PCPICH. In the cell where the soft handover cell is required. setting the parameter aims to ensure the soft handover area ratio required by the network planning. the parameter value is 10% of the cell downlink total transmit power.1. 4. 3. UL RTWP alarm system Monitor the uplink interference of network based on UL RTWP alarm reported by NodeB. In addition. 2005-07-13 All rights reserved Page 11 . setting the parameter aims to ensure the downlink coverage.1.WCDMA RNO Special Guide Coverage Problem Analysis Internal open 3. If the connection ratio is worse. UE probably fails to receive the data packet of FACH or receives an error data packet. For example. Intra-frequency cell reselection should precede the inter-frequency/inter-system cell reselection. 5. set the Sintrasearch to 7. When UE detects that serving cell quality (CPICH Ec/N0 measured by the UE) is lower than “minimum quality standard (that is. Qqualmin) of serving cell + the threshold”. Sintrasearch. MaxFACHPower This parameter defines the maximum transmit power of FACH (the maximum transmit powers of two FACHs in the MOD SCCPCH are FACH1MaxPower and FACH2MaxPower respectively). Sintersearch. 1. The measurement value of layer-3 filter has passed the layer-1 filter to eliminate basically the fast fading effect. the power waste is present. This parameter is defaulted to 5. in the area with dense cellular. layer-3 shall perform the smooth filter to shadow fading and seldom fast fading burr to provide better measurement data for the event decision. If the transmit power of FACH is too low. preamble power is not the required one and UE access fails. set the parameter to -1dB (corresponding to the pilot). The smooth capability and signal tracing capability should be balanced. inter-frequency cell reselection start threshold (Sintersearch). and Ssearchrat The parameters contain intra-frequency cell reselection start threshold (Sintrasearch). the Sintrasearch must be larger than Sintersearch and Ssearchrat. or 6. When setting the three parameters. in the area with dense cellular. 4 (that is. UE increase the power continuously and performs the access repeatedly to interfere with other users. 10dB). corresponding to the transmit power of PCPICH. PreambleRetransMax This parameter defines the maximum retransmission times of preamble in a preamble ascending cycle. This parameter is defaulted to 8.WCDMA RNO Special Guide Coverage Problem Analysis Internal open 2. For example. 4. 2. the stronger for the smooth capability of burr and the weaker the capacity of tracing the signal is. When the Ec/Io accessed at the edge cell is -12dB.3. Set the parameter based on difference scenarios. 8dB) and 2 (that is. The protocol recommends that the filter coefficient value be set to 0. start the intra-frequency/inter-frequency/inter-system cell reselection process. 4dB) respectively. If this parameter is too small. If the parameter is too large. set the parameter to 2.5. 2005-07-13 All rights reserved Page 12 . Set the parameters based on different scenarios. The layer-3 filter must filter the random impact capability to ensure the filtered measurement value reflects basic change trend of actual measurement. Therefore. The bigger the filter coefficient is. and inter-RAT cell reselection start threshold (Ssearchrat). If the transmit power of FACH is too large. Intra-FILTERCOEF This parameter means the measurement smooth coefficient adopted when layer-3 intra-frequency measurement report filters. increase the parameter. Total36 . Sintrasearch.4. 3. Setting the maximum transmit power of FACH can ensure target BLER. Sintersearch and Ssearchrat are defaulted to 5 (that is. WCDMA RNO Special Guide Coverage Problem Analysis Internal open 6. This parameter is defaulted to 0. Intra-CellIndividualOffset This parameter means cell CPICH measurement value offset of intra-frequency handover. During the preplanning phase. In the case of adjacent cell configuration. it aims to move the cell edge. Set the parameter based on actual environment of network planning. to trigger the handover easily. the transmit power is too lower due to SIR estimation erro. otherwise. the coverage result is inconsistent with the planning coverage. Consider RLMaxDLPwr from the persepective of the capacity. the downlink power contorl may be affected. As shown in Figure 1. use the coverage predication result of planning tools to evaluate and select the site distribution to ensure the network coverage balance. The receiving quality also may be affected. the easier the soft handover and the more the UE located in soft handover status but occupying many forward resources. Pilot coverage strength analysis The received strongest RSCP downlink in the coverage area must be more than -85dBm. In the handover algorithm.1 Coverage Data Analysis Drive Test Data Analysis 1. Total36 . which is used for intra-frequency handover decision of UE. 3. set and adjust the parameter based on actual Signal-Interference Ratio target value required by capacity design and actual traffic measurement indexes. Because the digital map may has no information of some buildings and deviation from actual site address. Adding this offset to actual value is used for event evaluation of UE. represented by relative value to CPICH. The pilot RSCP Best Server coverage also can measure whether site distribution is rational. If the full-coverage service is not required. the more difficult the soft handover is. unable to satisfy the performance requirement of service coverage. The smaller the parameter. The 2005-07-13 All rights reserved Page 13 . and it can be set to 15dB.If the RLMinDLPwr is too large. set a positive value. For the coverage void. Downlink Coverage I. Under the conditions. RLMaxDLPwr and RLMinDLPwr (oriented to the service) The parameters indicate the maximum transmit power and minimum transmit power of downlink DPDCH symbol. the area with the RSCP ranging from -105dBm to -85dBm in the road is present. 7.2 3. neglect the effect of the parameter. UE adds the original measurement value of the cell to this offset as the final measurement result. The larger the parameter. that is. the Ec/Io fading is generated. set a negative value. adopt the coverage enhancement technology to improve the coverage.2. If the RLMinDLPwr is too small. if the RSSI received by the downlink does not change dramatically. The power control dynamic adjustment range exists between the maximum transmit power and minimum transmit power. check the downlink coverage from the perspective of the data of Scanner. analyze the Ec/Io Best Server distribution of each cell by the Scanner when there is no user and 50% of users. avoid the incomplete pilot information measured by UE due to adjacent cell not configured. there is a difference of penetration loss ranging from 5dB to 7dB. the cell reselection and soft handover set the threshold based on the change of Ec/Io. 2005-07-13 All rights reserved Page 14 . which provides the important basis for RF optimization measures. Therefore. it may be thought no primary cell. Under normal circumstance. the primary cell analysis is required. In this way. Total36 . If an area has multiple Best Servers and Best Server changes frequently.WCDMA RNO Special Guide Coverage Problem Analysis Internal open pilot RSCP is normal from the perspective of Scanner and UE. If the antenna of Scanner is mounted outside the vehicle but the UE is in the vehicle. Primary cell analysis Currently. the cross-cell discontinuous coverage due to high site or pilot pollution (as shown in Figure 2) and coverage void present in the coverage edge ( as shown in Figure 3) easily cause no primary cell to generate the intra-frequency interference and ping-pong handover and affect service coverage performance. Therefore. Figure 1 Pilot strength distribution II. At the unloaded single site test and pilot coverage verification test phase before the optimization and downlink loaded 50% of service test phase after the optimization. Total36 . the Best Server in the active set when UE is in the connection mode or camped cell under the idle mode is inconsistent with Scanner primary cell. the Best Severs of Ec/Io of UE 2005-07-13 All rights reserved Page 15 . After the optimization.WCDMA RNO Special Guide Coverage Problem Analysis Internal open Figure 2 Pilot Ec/Io Best Server distribution Figure 3 Pilot Ec/Io Best Server distribution III. UE and Scanner coverage comparison analysis If the adjacent cells are not configured or soft handover parameter and cell reselection parameter are irrational. Import the data into an Excel table to obtain the probability density distribution. Meanwhile. For detailed operation method. and if the UE downlink power control is normal and network coverage is good. Downlink code transmit power distribution analysis Import the UE drive test data into BAM analysis software (Genex Assistant). see WCDMA RNO Special Guide Call Trace Data Collection. 2005-07-13 All rights reserved Page 16 . Figure 4 Comparison and analysis between the Scanner coverage and UE coverage IV. ensure that UE coverage figure has a definite Best Server borderline. as shown in Figure 4. Total36 . Although the maximum values and minimum values of each service downlink code transmit power are different.WCDMA RNO Special Guide Coverage Problem Analysis Internal open must be consistent with that of Scanner. Only the transmit powers in seldom areas are relatively high. the downlink code transmit powers of most points of whole network drive test are similar. The downlink code transmit power of NodeB can be recorded in the RNC BAM. as shown in Figure 5. and import the time aligned downlink code transmit power data and the data binning can be performed. The drive test data mainly analyzes the areas with the power higher than the mean and maximum downlink code transmit power for long. and cannot reflect the resource consumption from the soft handover and the effect on the system capacity. the soft handover area ratio is defined as follows: The soft handover ratio is the ratio of soft handover area dimension in the network to the total network coverage dimension. The external interference also should be considered. Soft handover ratio analysis According to the Scanner drive test data. V. define the soft handover ration from the perspective of traffic. If no pilot pollution is present. the BLER of downlink traffic transmission channel does not converge the target value. 2005-07-13 All rights reserved Page 17 . analyze the Best Server coverage of pilot Ec/Io in this area and the cell number in the active set and monitor set. and whether the downlink coupling loss increases due to intra-frequency interference by the pilot pollution. Total36 .WCDMA RNO Special Guide Coverage Problem Analysis Internal open Figure 5 Downlink code transmit power PDF of Voice service in the case of 50% load The mean downlink code transmit power obtained through the whole network drive test measures the downlink path loss and intra-frequency interference of the coverage area. concern further the change of downlink RSSI. compare with the data collected by Scanner and primary cell and analyze whether adjacent cell is neglected. Therefore. although the frequency sweeping test is performed during the site construction. And then. If RSSI increases dramatically. resulting in directly relatively higher downlink code transmit power. Compared with UE drive test data. Analyze first the Best Server coverage of pilot RSCP in this area and the path loss increases due to signal dead zone or coverage void. the ratio of drive test points in the soft handover state to all the drive test points is the soft handover ratio and must range from 30% to 40%. see WCDMA RNO Special Guide Call Trace Data Collection. the causes for uplink interference are not described here. the soft handover ratio is relatively high due to dense site. adopt the UE drive test data of the whole network. Uplink interference analysis The uplink RTWP data of each cell in the NodeB can be recorded in the RNC BAM. the antennas in the cell are space diversity receivers. trigger threshold and hysteresis of 1B event Increase CIO For the micro-cellular areas. Because it is similar to the design and installation of antenna and the each carrier has different features. as shown in Figure 6. The uplink interference is a major factor affecting the uplink coverage. because there is no user. Uplink coverage I. This part describes how to examine the uplink interference through uplink RTWP record.WCDMA RNO Special Guide Coverage Problem Analysis Internal open For example. Under normal conditions. During the network optimization. Total36 . For detailed methods. Adding soft handover ratio is contributed to: Reduce the filter coefficient and trigger time. After the binning. Figure 6 UE soft handover ratio 2. As shown in Figure 7. the change 2005-07-13 All rights reserved Page 18 . trigger threshold and hysteresis of 1A event Increase the trigger time. Figure 8 shows that the transmit power of UE is lower than 10dBm. whatever micro-cellular or macro-cellular. and network performance is worse. Figure 7 Abnormal UL RTWP recorded in the NodeB II. UE uplink transmit power distribution The transmit power distribution of UE illustrates the distribution of uplink interference and uplink path loss. The figure shows that the signal in the Tx/Rx antenna does not fluctuate but 20dBm fluctuation is present in the Rx antenna. Only when uplink interference or coverage area edge is present. the transmit power increases dramatically and is up to 21dBm and the uplink is restricted. indicating that intermittent interference is present in the secondary set. Total36 . Similar to the downlink coverage restriction when downlink code transmit power continuously reaches the maximum.WCDMA RNO Special Guide Coverage Problem Analysis Internal open trends of receiving signals of two antennas are the same. The uplink coverage restriction is present in the macro-cellular more easily than in micro-cellular. 2005-07-13 All rights reserved Page 19 . under normal conditions. the uplink interference also result in the uplink coverage restriction. Total36 .WCDMA RNO Special Guide Coverage Problem Analysis Internal open Figure 8 UE transmit power distribution (micro-cellular) Figure 9 UE transmit power distribution (macro-cellular) 2005-07-13 All rights reserved Page 20 . 2dB Better than -125dBm ≥52dB ≥35dB Single sector ≤ 180Km (it is configurable and the unit is 300m) BTS3806A 2.2dB Better than -125dBm ≥52dB ≥35dB Single sector ≤ 180Km (it is configurable and the unit is 300m) BTS3806 2. Serial NodeBs features Table 1 describes Huawei serial NodeBs configuration and features. Traffic distribution The coverage problem due to traffic volume measurement and imbalance of service distribution 3.2.2.2dB Better than -125dBm ≥52dB ≥35dB Single sector ≤ 180Km (it is configurable and the unit is 300m) Page 21 . (The methods of coverage analysis based on current network traffic data are still under way.3 Trace Data Analysis Supplement later (the methods of coverage analysis based on CDL are still under way) 3. Total36 Recei ve perfo rman ce Maximum receive search radius 2005-07-13 All rights reserved .WCDMA RNO Special Guide Coverage Problem Analysis Internal open 3.2dB Better than -125dBm ≥52dB ≥35dB Single sector ≤ 180Km (it is configurable and the unit is 300m) BTS3802C 2.) 1.2 Traffic Measurement Data Analysis Supplement later. congestion ratio.4 User Complaints Analysis Supplement later (the methods of coverage analysis based on user complaints are still under way) 4 4.2dB Better than -125dBm ≥52dB ≥35dB Single sector ≤ 180Km (it is configurable and the unit is 300m) RRU3802C 2. Table 1 Huawei serial NodeBs and features (V100R003) Version Static noise coefficient Static receiver sensitivity Receive adjacent channel selectivity Receive dynamic range BTS3812 2. Traffic measurement indexes The effect on access success ratio.1 Coverage Enhancement Strategies NodeB Configuration Adjustment 1. Excessive busy/idle cell The effect on the coverage based on the load adjustment 3. and handover success ratio from the coverage 2. call drop ratio.2. the set top port output ≥2×25W (diversity) Satisfy the 141 protocol of 3GPP ≥10dB ≥22dB ≤±2dB ( all the temperatures ).1% PS144K BLER=0. the set top port output ≥2×25W (diversity) Satisfy the 141 protocol of 3GPP ≥10dB ≥22dB ≤±2dB (all the temperature s ). the set top port output≥2×25W (diversity) Satisfy the 141 protocol of 3GPP ≥10dB ≥22dB ≤±2dB (all the temperatures).≤±1dB (normal temperature ) 6 Under the condition of single carrier wave.2K BLER=1% CS64K BLER=0.334(1 0W maximum value)250(fo ur-antenna receive a maximum of 5W )358(fou r-antenna receive a maximum of 5W) 2 128*2 (128*2) 32*2 (40*2) 32*2 (48*2) 16*2 (24*2) 8*2 (12*2) 1*1 no diversity Power consumption Powe r consu mptio n 1*1 diversity 1118 (typical value)1212 (maximum value) 1078 (typical value)1172 (maximum value) 2005-07-13 All rights reserved Page 22 .5dB Capa city desig n specif icatio ns Single cabinet maximum sector number Single sector maximum carrier wave number Single cabinet maximum Cell number AMR12.≤±1dB (normal temperature) 3 Internal open Transmit power Under the condition of single carrier wave.WCDMA RNO Special Guide Coverage Problem Analysis Under the condition of single carrier wave.1% PS64K BLER=0.1% PS384K BLER=0. ≤±1dB (normal temperature) 2×5W (diversity) or 2×10W (diversity) 2×5W (diversity) or 2×10W (diversity) Trans mit perfo rman ce Spurious emission Static transmit power control range Dynamic transmit Power control range Satisfy the 141 protocol of 3GPP ≥10dB ≥22dB Satisfy the 141 protocol of 3GPP ≥10dB ≥22dB Transmit power absolute accuracy ≤±0. Total36 .214(1 0W maximum value) 235(5W maximum value).5dB ≤±0.1% 3 2 2 4 2 2 2 2 12 128*12 (128*12) 32*12 (40*12) 32*12 (48*12) 16*12 (24*12) 8*12 (12*12) 708 (typical value)762 (maximum value) 6 128*6 (128*6) 32*6 (40*6) 32*6 (48*6) 16*6 (24*6) 8*6 (12*6) 668 (typical value)722 (maximum value) 6 128*6 (128*6) 32*6 (40*6) 32*6 (48*6) 16*6 (24*6) 8*6 (12*6) 2 64 (64) 16 (20) 16 (24) 8 (12) 4 (6) 159(5W maximum value). In the case of heating. it is 3679W/3 892W.WCDMA RNO Special Guide Coverage Problem Analysis Air-condition Type: under the normal temperature In the case of cooling. it is 2579W/2 792W. Page 23 . it is 4579W/4 792W. in the case of cooling. it is 2310W/2 478W. Heat exchanger type: In the case of cooling. In the case of heating. in the case of heating. it is 2930W (typical value)/30 98W (maximu m value). Total36 3 *2 no diversity 3023 (typical value) 3316 (maximum value) 1829 (typical value)2017 (maximum value) 2005-07-13 All rights reserved . it is 4310W/4 478W Internal open 3 * 1 no diversity 1633 (typical value)1780 (maximum value) 1593 (typical value)1740 (maximum value) 3 * 1 diversity 3023 (typical value) 3316 (maximum value) 1663 (typical value)1836 (maximum value) Air-condition Type: under the normal temperature. Heat exchanger type: in the case of cooling. it is 4310W/4 478W. 85 58.ITU I.703.957 Support Support (each (each interface interface Support (each processing processing interface unit supports unit supports processing unit three three supports three optic-fiber optic-fiber optic-fiber interfaces interfaces interfaces and and single and single single optic-fiber optic-fiber optic-fiber supports at supports at supports at most four most four most four Not support main/diversit main/diversit main/diversity y RF remote y RF remote RF remote modules.ITU G.432. Total36 All rights reserved . and the distance between NodeB and RRU transmission signal cell is no more than 100Km) ANSI T1.5 65 null null Null Null 6* 2 no diversity Sound power lever(Bel) noise Sound pressure level(dBA) STM-1 RRU suppo rt RRU (maximum distance between RRU and NodeB is 40Km. and modules.WCDMA RNO Special Guide Coverage Problem Analysis in the case of heating. and macro macro macro NodeB NodeB NodeB supports at supports at supports at most six RRI most 12 most six transmission RRU RRU signal transmission transmission coverage cells) signal signal coverage coverage cells) cells) Support Support Support Support Support Support Support Support Support Support Open loop transmit Diversity Closed loop transmit diversity mode 1 Diver sity Closed loop transmit diversity mode Support Support Support Support Support Two-antenna receive 2005-07-13 Support Support Support Support Support Page 24 . and modules. it is 4867W/5 080W Internal open 3 *2 diversity 3009 (typical value) 3317 (maximum value) 3515 (typical value) 3828 (maximum value) 7 60 6.105-1995.5 7.2 G. that is. From the perspective of macro-cellular. which directly affect the system capacity. the service coverage performance also improves. Adjust the RRM algorithm parameters (such as active set size and soft handover threshold) to maintain about 40% of soft handover ratio. When the NodeB transmit power does not exceed. The radio propagation feature of micro-cellular is to mount the antenna in different directions and cannot ensure sufficient separation between the primary cell and other cells in the coverage cell. For 3G NodeB co-located with 2G. When NodeB expands to three sectors from one sector. soft handover area ratio and allowed maximum propagation path loss. Total36 . The most importance factor for affecting the sectorization performance is the antenna selection. When the sector adds. further reduce the maximum path loss of cell or adding NodeB transmit power does not improve the NodeB capacity unlimitedly. When the NodeB expands to six sectors. In this way. micro-cellular sectorization does not exceed two sectors. While adding the sectors. optimize the parameters involved in the downlink load formula to improve the NodeB capacity. the capacity is 1. the side lobe of antenna also increases. Pay enough attention to the antenna selection to ensure the appropriate inter-cell separation. Under the normal condition. the antenna increases and the separation must consider.WCDMA RNO Special Guide Coverage Problem Analysis diversity Four-antenna receive diversity S-CPICH/Cell Chan nel DSCH CPCH TTA Other s OTSR Electrical antenna support Cell breathing Support Not support Not support Not support Support (12dB) Support Support Support Not support Not support Not support Not support Support (12dB) Support Support Support Not support Not support Not support Not support Support (12dB) Support Support Support Support Not support Not support Not support Not support Not support Not support Support Internal open Support Not support Not support Not support Not support Not support Not support Support 2. the added NodeB sectors help improve the capacity. meanwhile. The service coverage is affected by allowed maximum propagation path loss. In addition. At that time. reduce the Eb/No or adjacent cell interference through the optimization methods to improve the downlink capacity of NodeB. reduce appropriately the maximum path loss of cell and the NodeB can support more users.8 times of three-sector capacity. For example. it determines inter-cell interference level. the antenna gain and adjacent cell interference increase.8 times of original capacity. for most directional antennas. Sectorized configuration Use the sectorization to improve the system capacity. the sector selection focuses on the antenna installation. 2005-07-13 All rights reserved Page 25 . each NodeB also can be expanded to six sectors. the NodeB capacity is 2. Widely speaking. Improve the uplink sensitivity by 2. adopt four-antenna receiving diversity to decrease the Eb/No requirement by demodulation. Eb/No requiredby the uplink demodulation increases dramatically. Tower mounted amplifier Tower mounted amplifier (TMA) reduces the total noise coefficient of NodeB receiving subsystem to improve the uplink coverage performance and the coverage gain depends on the mechanism of receiving subsystem and the feeder loss. Transceiver diversity In the downlink. the effect on the system capacity from the repeater depends on: Link budget between primary NodeB and repeater Repeater power transmission setting Maximum path loss related to repeater coverage area Service allocation between host cell and repeater Meanwhile. Repeater The repeater expands the coverage range of primary cell. WCDMA repeater is similar to the analog repeater and the noise and signal are expanded at the same time. If the uplink of system capacity is restricted. The uplink/downlink budget improves and remote coverage through RRU means that coverage performance increases but the capacity does not reduce. Under the condition of LOS. the indoor depth coverage of repeater is also an effective way.5-3dB.WCDMA RNO Special Guide Coverage Problem Analysis Internal open 4. Typically. the TMA reduces the system capacity. The repeater increases the Eb/No required by uplink/downlink demodulation.0dB. 4. the gain of two-antenna four receiving diversity is about 2. If the system capacity is restricted downlink. provide the Time Switched Transmit Diversity (TSTD) and Space Time Transmit Diversity to add the RAKE receiver number of UE and improve the quality to increase the coverage range. 2005-07-13 All rights reserved Page 26 . 3. improve the system capacity and reduce the NodeB number.2 Coverage Enhancement Technology 1. Compared with the remote coverage through the RRU. the TMA adds the maximum path loss and introduces insertion loss to reduce the EIRP of NodeB. If the downlink of system capacity is restricted. and reduce the site quantity by 25%-30%. Total36 . and most repeaters do not adopt uplink receiving diversity technology. In this way. 2.5-3. compared with two-antenna two receiving diversity. use the repeater to reduce the system capacity. In the uplink. Remote RF amplifier The remote RF amplifier allows the physical separation of NodeB RF module and baseband module and RF module is placed far away without using long feeder. the capacity loss ranges from 6% to 10%. 1 5. 6. and is less than the signal coverage level of peripheral area and the coverage void is present. At that time.WCDMA RNO Special Guide Coverage Problem Analysis Internal open 5. 5 5. Total36 . the micro-cellular can solve the high capacity and applicable for city and dense city.1 Typical Coverage Problems Coverage Void due to Inappropriate Site Planning Problem Description In partial sites of coverage area. the pilot signal strength is less than -90dBm. Micro-cellular The city and dense areas require high NodeB density and the site selection is also difficult. Omni Transmission Sectorized Receive Technology Omni Transmission Sectorized Receive (OTSR) transmits in the omni-direction and receives with three sectors. It is applicable for wide coverage and low user density. The micro-cellular can effectively use blockings of buildings to reduce the interference ratio of adjacent cell and improve the downlink capacity. the coverage radius is farther. Because the gain of directional antenna is higher than that of omni-directional antenna. lower capacity requires and OTSR can reduce the network construction cost and improve the coverage range. At the earlier stage of network construction.1. 2005-07-13 All rights reserved Page 27 . For the areas with mean traffic.1. that is. Total36 .WCDMA RNO Special Guide Coverage Problem Analysis Figure 10 Coverage void due to irrational site distribution Internal open 5. the signal fluctuation is basically not present in the coverage area. Figure 11 Coverage prediction of XX pilot 2005-07-13 All rights reserved Page 28 . the cellular density also should be average. In this way.2 Analysis The drive test data and coverage simulation prediction of actual network construction in Figure 11 show that the pilot signal strength Ec in some areas is less than -90dBm. avoid the area with signal fading from the perspective of network design. The inter-site distance also illustrates the cause of lower coverage level in the central areas. Therefore. 2005-07-13 All rights reserved Page 29 .1 Cross-cell Coverage due to Inappropriate Site Selection Problem Description In the XX pilot. Total36 .WCDMA RNO Special Guide Coverage Problem Analysis Internal open Figure 12 Site distribution 5. the site of XX road is 60 meters high and 20 meters higher than peripheral average buildings.2. the cross-cell coverage is present easily and the intra-frequency interference with other sites is generated.2 5. this optimization does not change. Total36 . the cross-cell coverage problem is not found at the planning phase. replace the 2° of fixed electrical tilt antenna with 6°. Add the mechanism tilt angle and adjust the directional angle to solve the cross-cell coverage.2 Analysis For the high site problem. adjust the antenna directional angle and tilt angle to reduce the interference with other sites. especially in the primary cell of NodeB in the XX road. but some cross-cell coverage is still present in the road.WCDMA RNO Special Guide Coverage Problem Analysis Internal open Figure 13 Cross-cell coverage before the optimization 5.2. Therefore. 2005-07-13 All rights reserved Page 30 . Because the city construction speeds up and the digital map does not contain the features of new buildings to result in the inaccurate pilot coverage prediction in some areas. Figure 14 shows that the cross-cell coverage in most areas is solved. Because the XX road is at the network coverage edge. 3. At the optimization phase after the network construction.1 Coverage Restricted due to Irrational Antenna Installation Problem Description The Pilot Network: 701070_ParkLaneHotel site of S project covers the V Park and the antenna is mounted on the platform (10 meters high).3 5. before the traffic light under the antenna. Total36 . 2005-07-13 All rights reserved Page 31 . as shown in Figure 15.WCDMA RNO Special Guide Coverage Problem Analysis Internal open Figure 14 Cross-cell coverage after the optimization 5. Video Phone mosaic adds and image quality is worse and PS 384K service is reactivated. as shown in Figure 16.2 Analysis From the perspective of planning. 3G antenna is close to the platform and the wall blocks the signal to not satisfy the installation conditions of antenna. Therefore.WCDMA RNO Special Guide Coverage Problem Analysis Internal open Figure 15 Coverage restriction at the bottom of site without considering the shielding of platform 5. From the perspective of antenna installation scenarios. that is.3. change at least the solution without affecting the 2G coverage and connect the transceiver feeders of 3G and 2G respectively with two antennas of external broad frequency polarization antenna. Compared with 2G coverage test data. Total36 . Meanwhile. if the antennas of 3G network and 2G network are in the same location. 2005-07-13 All rights reserved Page 32 . 2G network has not large signal fluctuation under the road and site. the road’s 3G coverage should be caused by 701070_ParkLaneHotel_Podium site. After the discussion with 2G network engineers. 3G network and 2G network co-locate. 2G antenna and installation components affect the 3G antenna patter. it is difficult to change 3G antenna location. and connect other transceiver feeders of 3G and 2G with two antennas of internal broad frequency antennas. Figure 17 shows the comparison of pilot RSCP before and after the antenna installation correction. the coverage of sector A is 20dB stronger than that of sector B and sector C. During the antenna installation at the NodeB construction phase. 701640_ElzHse1 site has only one cell and combined by transmitter A.4. 2005-07-13 All rights reserved Page 33 . especially for the micro-cellular site.2 Analysis The pilot RSCP before the antenna correction in the Figure 17 shows that the signals close to the bottom of the site are below -76dBm. and is the combination of three antenna receiving signals and distribution of NodeB transmission signal). it is difficult to find the pilot RSCP is larger than -85dBm.WCDMA RNO Special Guide Coverage Problem Analysis Figure 16 Optimization of antenna design implementation Internal open 5. obviously. The problem is found after RF engineers test RTWP interference at the site. Figure 17 Pilot RSCP coverage before and after the correction of antenna installation of 701640_ElzHse site 5. so sector B and C have no signals to transmit and the coverage effect is worse. Compared the coverage of three sectors.1 Coverage Restricted due to Antenna Installation Failure Problem Descriptions In the Pilot network of S project. B and C (It is not OTSR.4 5. Before the problem is found. From the perspective of current single site test Checklist.4. the single site test is passed and the problem is not found in the later network optimization test. all the transmission feeders are combined to sector A by mistake. Total36 . use the 2G coverage distribution to check whether the 3G coverage is normal. the sites are basically normal. For example. Cross-cell coverage Concern the repeated coverage due to inconsistent site height. 6. 3. 6.3 RF Optimization Phase 1. 2. Currently. 2. Total36 . Ec/Io mean Under the unloaded downlink and loaded downlink. compare the distribution area ranging from -90dBm to -80dBm. Signal dead zone Concern the major coverage target of each transmitter and confirm whether the signal dead zone is present based on the specified target. and only when the minimum working level at the bottom of 3G sites also should reach about -60dBm. 2. the minimum working level of 2G network is about -60dBm. Coverage void Concern whether the continuous coverage of full-coverage service can be guaranteed.WCDMA RNO Special Guide Coverage Problem Analysis Internal open Most sites of S project share 2G sites location or sector. Therefore. 6 6. Pilot pollution Concern whether the ping-pong handover exists in the soft handover area to reduce the 2005-07-13 All rights reserved Page 34 . and perform a comparison and verification between the coverage prediction and actual drive test data.2 Evaluation Phase before the Optimization 1. Planning verification Concern the difference between the digital map and actual environment.1 Concerns at the Network Optimization Phases Single Site Test Phase 1. Uplink/downlink interference Concern the change of uplink RTWP of each cell. Scanner in the drive test or RSSI of UE. concern whether the areas less than the mean value affects continuous coverage of full-coverage service 3. RSCP mean Concern whether areas with the mean value affect continuous coverage of full coverage service. technology. Although the coverage indexes are not reflected in the KPI. Only the radio performance optimization based on the requirement takes effect. and WCDMA experience (personnel. 2005-07-13 All rights reserved Page 35 . Traffic measurement indexes Concern the inconsistency between the specified coverage target and actual user traffic distribution.WCDMA RNO Special Guide Coverage Problem Analysis Internal open intra-frequency interference. the coverage optimization is the basic requirement for improving the network performance. 7 Summary The network optimization can improve the whole network quality by the mobile users and utilizes effectively network resources. 6.5 Network Optimization Project Acceptance Phase 1.4 Parameter Optimization Phase 1. Total36 . 6. Soft handover ratio Concern the capacity restriction due to over-high soft handover ratio. and tools) plays a vital role. Huawei WCDMA R & D Caliber Summary 20040302.WCDMA RNO Special Guide Coverage Problem Analysis Internal open List of reference 1. 2.doc 2005-07-13 All rights reserved Page 36 .00 by Jamal. Total36 .xls WCDMA Radio Network Optimization---RF Optimization Guidelines V1.
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