Monitoring

2.7 Downlink Load 2.7.1 Monitoring Principles The downlink capacity of a cell is limited by its total available transmit power, which is determined by the NodeB power amplifier capability and the power configured for the cell. The downlink transmit power consists of the following, as shown in Figure 2-7:  Common channel (CCH) power  Non-HSPA power without CCH  HSPA power  Power margin Figure 2-7 Dynamic power resource allocation Downlink power resources are allocated as follows: 1. Downlink power resources are first reserved for common physical channels and allocated to the DPCH. The remaining power resources are available for HSPA, including HSUPA and HSDPA. The HSPA power resources are first allocated to the HSUPA downlink control channels, including the E-AGCH, E-RGCH, and E-HICH. The remaining power resources are available for HSDPA. The HSDPA power resources are first allocated to the downlink control channel HSSCCH. The remaining power resources are available for the traffic channel HS-PDSCH. 2. 3. Downlink power consumption is related to cell coverage, UE locations, and the traffic load in the cell. Large cell coverage, UEs being far away from the cell center, and heavy traffic load all contribute to large downlink power consumption. Therefore, downlink power overload is more likely to occur in hotspots or in cells with large coverage. When the downlink transmit power is insufficient, the following occurs:  The cell coverage shrinks.  The mean utility ratio of the transmitted carrier power for non-HSPA users in a cell (including non-HSPA users on CCHs) is calculated using the following formula: MeanNonHSTCP Utility Ratio = MeanNonHSTCP/MAXTXPOWER x 100%  The mean utility ratio of the transmitted carrier power for all users in a cell is calculated using the following formula: MeanTCP Utility Ratio = MeanTCP/MAXTXPOWER x 100%    To obtain MAXTXPOWER.1 Monitoring Principles Use the RTWP to measure the uplink cell capability on WCDMA networks.MeanTCP.  New service requests are likely to be rejected. add a carrier for the current sector if possible.8 Uplink Load 2.MeanChThroughput: mean downlink throughput of single HSDPA MAC-d flows for cell The downlink cell load is indicated by the mean utility ratio of transmitted carrier power in a cell." 2.  For cells with light traffic and poor coverage.7. 2. add a NodeB or split the sector if the number of carriers in the sector reaches the maximum. add a NodeB.  The service quality declines. intra-system interference. RTWP includes the background noise.HSDPA.MeanTCP: mean transmitted power of carrier for cell  VS.8. The data throughput decreases.  The MeanTCP Utility Ratio is greater than 85% and the value of the VS. run the LST UCELL command. and RF interference.NonHS: mean Non-HSDPA transmitted carrier power for cell  VS. and convert the parameter value from the unit "0.HSDPA.7. query the value of the Max Transmit Power of Cell parameter. Intrasystem interference includes the uplink signals sent by the UEs in the serving and neighboring cells. RF interference includes the RF interference from an external source (for example. 300 kbit/s) required by subscribers during peak hours for three consecutive days in one week. The capacity expansion methods are as follows:  For cells with heavy traffic.1 dBm" to "watt. 2. the RF interference from another RAT or from equipment other than communication equipment) .3 Optimization Suggestions Perform capacity expansion in the following scenarios:  The MeanNonHSTCP Utility Ratio is greater than 70% during peak hours for three consecutive days in one week.2 Monitoring Methods The following TCP-associated counters are defined for Huawei RNCs:  VS.MeanChThroughput counter is lower than the value (for example. The uplink cell capacity is restricted by the rise over thermal (RoT). a 3 dB noise increase corresponds to 50% of the uplink load and a 6 dB noise increase corresponds to 75% of the uplink load.and intra-system RF interference (for example. The formula is as follows: If there is no RF interference. The NodeB measures the RTWP on each receive channel in each cell.8. The cell RTWP obtained by the RNC is the linear average of the RTWPs measured on all receive channels in a cell under the NodeB. hardware faults (for example.MeanRTWP: average RTWP in a cell  VS. the cell coverage shrinks. or new service requests are rejected. If the RTWP value is too large. The RTWP reflects the interference to a NodeB and indicates the signal strength on the RX port on the RF module. Figure 2-8 Relationship between RTWP. intermodulation interference produced by hardware components). and uplink load A large RTWP value in a cell is caused by traffic overflow.MinRTWP: minimum RTWP in a cell . noise increase. Under this condition. or external interference. the RoT is generated by intra-system interference.2 Monitoring Methods The RTWP and Equivalent Number of Users (ENU) are indicated by the following counters:  VS. 2. poor quality of antennas or feeder connectors). the quality of admitted services declines. the RoT is used as a criterion to evaluate the uplinkload. which equals the RTWP minus the cell background noise. The relationship between the RoT and the uplink load factor is as follows: For example. MinRTWP counter (the RTWP value obtained when the cell carries no traffic) is considered the background noise. The RTWP of a cell is considered too high when the value of the VS.MeanRTWP counter is greater than 90 dBm after hardware faults and external interference are rectified. A cell is considered heavily loaded if the UL ENU Ratio exceeds 75% during peak hours for two or three consecutive days in one week. Alarm ID ALM-26522 ALM-26521 ALM-26532 ALM-26752 ALM-26758 ALM-26755 ALM-26757 ALM-26541 ALM-26529 Alarm Name RF Unit RX Channel RTWP/RSSI Unbalanced RF Unit RX Channel RTWP/RSSI Too Low RF Unit Hardware Fault ALD Hardware Fault TMA Running Data and Configuration Mismatch TMA Bypass RET Antenna Running Data and Configuration Mismatch ALD Maintenance Link Failure RF Unit VSWR Threshold Crossed  If the value of the VS. the background noise increases to -106 dBm or above due to external interference or hardware faults. there are hardware faults or external interference. If the value of the VS.UL. enable the following features as required: − − WRFD-140215 Dynamic Configuration of HSDPA CQI Feedback Period WRFD-010712 Adaptive Configuration of Traffic Channel Power offset for HSUPA .EqvUserNum: number of uplink ENUs on all dedicated channels in a cell The ENU can be specified by the following parameter: UlTotalEqUserNum: UL total equivalent user number.RAC. VS.MeanRTWP counter is greater than 90 dBm during peak hours for three consecutive days in one week. 2.MinRTWP counter is greater than -100 dBm or less than -110 dBm during off-peak hours for three consecutive days in one week. The following table lists the RF alarms reported by the NodeB. the value of the VS.8.3 Optimization Suggestions Perform capacity expansion in the following scenarios:  If the value of the VS. Locate and rectify the faults. Locate and rectify the faults.UL.EqvUserNum/UlTotalEqUserNum In some areas. The uplink ENU ratio (UL ENU Ratio) is calculated using the following formula: UL ENU Ratio = VS.MeanRTWP counter is greater than -100 dBm during off-peak hours or greater than -90 dBm during peak hours for two or three consecutive days in one week. If this occurs. which can be queried using the RNC command LST UCELLCAC.RAC. hardware faults or external interference exists. 1 Monitoring Principles On WCDMA networks. 16 SF16 codes. In a WCDMA cell. see Power Control Feature Parameter Description in RAN Feature Documentation. For . OVSF codes distinguish the downlink physical channels of different UEs in a cell.  If the number of uplink ENUs is insufficient and the amount of uplink power is sufficient. An OVSF code tree can be divided into 4 SF4 codes. and all user data is transmitted over the same central frequency almost at the same time. each cell is allocated a unique scrambling code. run the MOD UCELLCAC command with the UL total equivalent user number parameter set to a larger value.. If there are no additional UARFCNs available. add NodeBs as required.. 8 SF8 codes. each UE is allocated a unique scrambling code. If the uplink capacity of the cell still does not meet the requirements after the preceding features are enabled. For details about how to enable the "WRFD-140215 Dynamic Configuration of HSDPA CQI Feedback Period" feature.. different user data is distinguished by CDMA technique. Therefore. run the SET UADMCTRL command with the AF of hsupa interactive service andAF of hsupa background service parameters set to 10. In the downlink. That is. In the uplink. see Dynamic Configuration Based on the Uplink Load Feature Parameter Description in RAN Feature Documentation. OVSF codes provide perfect orthogonality. In addition. add carriers as required.9 OVSF Code Usage 2. Each channel uses two types of code: scrambling code and orthogonal variable spreading factor (OVSF) code.  For details about how to enable the " WRFD-010712 Adaptive Configuration of Traffic Channel Power offset for HSUPA" feature. . channels are distinguished by code. 2. 256 SF256 codes. all UEs in a cell use the same scrambling code but each of them is allocated a unique OVSF code.9. the maximum spreading factor (SF) is 256. Figure 2-9 OVSF code tree In the downlink. Figure 2-9 shows an OVSF code tree. minimizing interference between different users. Codes with various SFs can be considered as equivalent to SF256 codes. HSPDSCH code resource management can be performed at both RNC and NodeB levels. HSDPA and R99 services share OVSF codes. NodeB-controlled dynamic code allocation is enabled through the DynCodeSw parameter. Figure 2-10 RNC-controlled static code allocation Figure 2-11 shows RNC-controlled dynamic code allocation. HSDPA services do not require admission control based on cell code resources. only one OVSF code tree is available. the OVSF code usage can be calculated for a user or a cell. Figure 2-12 shows NodeB-controlled dynamic code allocation.example. In a cell. once a code is allocated to a user. but are non-orthogonal to their parent or child codes. If available OVSF codes are insufficient. Using this method. a code with SF8 is equivalent to 32 codes with SF256. OVSF code resources are limited. Figure 2-10 shows RNC-controlled static code allocation. As a result. After HSDPA service is introduced. sibling codes are orthogonal to each other. Therefore. RNCcontrolled static or dynamic code allocation is enabled through the Allocate Code Mode parameter. In the OVSF code tree. Figure 2-12 NodeB-controlled dynamic code allocation . and these code resources can be shared among HSDPA services. Figure 2-11 RNC-controlled dynamic code allocation The system reserves code resources for HSDPA services. neither its parent nor child code can be allocated to any other user. a new call request is rejected. SF16>) x 16 + (<VS. see HSDPA Feature Parameter Description in RAN Feature Documentation.SF32> + <VS. The codes available for the DCH can be calculated using the following formula: DCH_OVSF_CODE = (<VS.3 Optimization Suggestions If the value of the DCH_OVSF_Utilization counter is greater than 70% during peak hours for three consecutive days in one week.  Add a carrier or split the sector.SF128>) x 2 + (<VS.MultRAB.SF4> + <VS.NodeB-controlled dynamic code allocation is more flexible than RNC-controlled dynamic code allocation. Preferentially allocate idle codes to HSDPA UEs to improve the HSDPA UE throughput.MultRAB.RAB.SF32>) x 8 + (<VS.SF64>) x 4 + (<VS. and two HS-SCCHs.MultRAB.SF16> + <VS.SFOccupy counter. a cell runs out of OVSF codes. one E-AGCH.SingleRAB.SF8> + <VS. OVSF code usages are calculated as follows:  OVSF_Utilization = VS.(Codes occupied by CCHs + Codes occupied by E-AGCHs + Codes occupied by E-RGCHs and E-HICHs + Codes reserved for HS-PDSCHs + HSSCCH codes) For example. Then.SF128> + <VS. one ERGCH/E-HICH. Recommended measures are as follows:  Enable the WRFD-010631 Dynamic Code Allocation Based on NodeB feature if this feature has not been enabled. .SingleRAB.  Enable the WRFD-010653 96 HSDPA Users per Cell feature if this feature is supported.SingleRAB.MultRAB.MultRAB. if the following conditions are met:  A cell that supports HSPA is configured with one SCCPCH.SingleRAB. It shortens the response time and saves the Iub signaling used for code allocation.SingleRAB.SF64> + <VS.(8 + 1 + 2 + 16 + 4) = 225. which is measured by the VS.SF256> + <VS.SingleRAB. For details about how to enable the "WRFD-010631 Dynamic Code Allocation Based on NodeB" feature and the "WRFD-010653 96 HSDPA Users per Cell" feature.9.MultRAB.SF4>) x 64 + (<VS.SingleRAB.MultRAB.SF8>) x 32 + (<VS.RAB.SF256>) The maximum number of codes available for the DCH can be calculated using the following formula: DCH_OVSF_CODE_Ava = 256 . 2.  At least one code is reserved for HSDPA services. DCH_OVSF_CODE_Ava = 256 .SFOccupy/256 x 100%  DCH_OVSF_Utilization = DCH_OVSF_CODE/DCH_OVSF_CODE_Ava 2.2 Monitoring Methods Huawei RNCs monitor the average usage of an OVSF code tree based on the number of equivalent codes with SF256.9. 10. the stronger the service processing capability of the NodeB. CE resources allocated by licenses are shared among services on the NodeB.10 CE Usage 2. Rateone RLC PDU).  If CE Overbooking is disabled: The RNC calculates the usage of CEs for admitted UEs by adding up credit resources reserved for each UE. If available CE resources are insufficient.4 13. − − R99 UE: The NodeB calculates the usage of credit resources for an R99 UE based on the MBR. − − R99 UEs: The RNC calculates the usage of credit resources for an R99 UE based on the mobility binding record (MBR).1 Monitoring Principles CEs are baseband resources provided by NodeBs and measure the baseband capability of NodeBs. Rateone RLC PDU). Signaling carried on an associated channel of the dedicated channel (DCH) does not consume extra CE resources. HSUPA UE using a 2 ms TTI: The NodeB adjusts the credit resource usage of such a UE based on the UE's rate and the minimum number of CEs reserved for admitting such a UE. HSUPA UE: The RNC calculates the usage of credit resources for an HSUPA UE based on MAX(GBR. The NodeB sends the response message that carries its CE capability to the RNC. CCHs do not require extra CE resources because the RNC reserves CE resources for services on these channels. After the adjustment. The value range is 1 to 8. The CE capability of the NodeB is limited by both the installed hardware and the configured software licenses.  If CE Overbooking is enabled: The NodeB calculates the usage of credit resources for all admitted UEs at the cell and NodeB levels and periodically reports the measurement result to the RNC. Downlink CE resources are associated with the baseband processing boards where a cell is set up. Uplink CE resources can be shared in an uplink resource group.6 256 64 2 2 4 4 . the NodeB rejects a new call request. Rateone RLC PDU). Table 2-3 to Table 2-8 provide the number of CEs consumed by different services. HSUPA UE using a 10 ms transmission time interval (TTI): The NodeB adjusts the credit resource usage of such a UE based on the UE's rate. the credit resources consumed by such a UE must be less than the credit resources required by MAX(GBR. − The minimum number of CEs reserved for admitting an HSUPA UE using a 2 ms TTI is 4 by default. After the adjustment. The more CEs a NodeB supports. Table 2-3 Uplink CEs consumed by an R99 service Direction Rate (kbit/s) SF 2RX:Number of CEs Consumed 1 1 2RX:Corresponding Credits Consumed 4RX:Number of CEs Consumed 2 2 4RX:Corresponding Credits Consumed UL 3.2. The usage of CEs for admitted UEs is calculated in different ways depending on whether the CE Overbooking feature is enabled. but not between uplink resource groups. the credit resources consumed by such a UE must be less than the credit resources required by MAX(GBR. One CE can be consumed by a 12.2 kbit/s voice call. Direction Rate (kbit/s) SF 2RX:Number of CEs Consumed 1 1 1.4 13. SRB over DCH) Direction Rate (kbit/s) SF > minSF UL 32 64 128 Rate (kbit/s) SF = minSF 64 128 256 32 16 8 SF 2RX:Number of CEs Consumed 2RX:Corresponding Credits Consumed 4RX:Number of CEs Consumed 4RX:Corres Credits Con 1 2 4 2 4 8 2 2 4 4 4 8 .6 8 16 32 64 128 144 256 384 SF Number of CEs Consumed Corresponding Consumed 1 1 1 1 1 2 4 4 8 8 Credits DL 256 128 128 128 64 32 16 16 8 8 1 1 1 1 1 2 4 4 8 8 Table 2-5 CEs consumed by an HSUPA service (10 ms TTI.5 3 5 5 10 10 2RX:Corresponding Credits Consumed 4RX:Number of CEs Consumed 2 2 2 3 5 5 10 10 4RX:Corresponding Credits Consumed 8 16 32 64 128 144 256 384 64 64 32 16 8 8 4 4 2 2 3 6 10 10 20 20 4 4 4 6 10 10 20 20 Table 2-4 Downlink CEs consumed by an R99 service Direction Rate (kbit/s) 3. Direction Rate (kbit/s) SF > minSF 608 1280 1800 Rate (kbit/s) SF = minSF 608 1280 1800 SF 2RX:Number of CEs Consumed 2RX:Corresponding Credits Consumed 4RX:Number of CEs Consumed 4RX:Corres Credits Con 4 2SF4 2SF2 8 16 32 16 32 64 8 16 32 16 32 64 Table 2-6 CEs consumed by an HSUPA service (2 ms TTI. SRB over HSUPA) Direction Rate (kbit/s) SF > minSF UL 16 32 128 608 1280 1800 Rate (kbit/s) SF = minSF 64 128 256 608 1280 1800 32 16 8 4 2SF4 2SF2 SF 2RX:Number of CEs Consumed 2RX:Corresponding Credits Consumed 4RX:Number of CEs Consumed 4RX:Corres Credits Con 1 2 4 8 16 32 2 4 8 16 32 64 2 2 4 8 16 32 4 4 8 16 32 64 Table 2-8 CEs consumed by an HSUPA service (2 ms TTI. SRB over HSUPA) Direction Rate (kbit/s) SF > minSF UL 608 1280 Rate (kbit/s) SF = minSF 608 1280 4 2SF4 SF 2RX:Number of CEs Consumed 2RX:Corresponding Credits Consumed 4RX:Number of CEs Consumed 4RX:C Credi 8 16 16 32 8 16 16 32 . SRB over DCH) Direction Rate (kbit/s) SF > minSF UL 608 1280 2720 Rate (kbit/s) SF = minSF 608 1280 2720 4 2SF4 2SF2 SF 2RX:Number of CEs Consumed 2RX:Corresponding Credits Consumed 4RX:Number of CEs Consumed 4RX:Corres Credits Con 8 16 32 16 32 64 8 16 32 16 32 64 Table 2-7 CEs consumed by an HSUPA service (10 ms TTI. NodeB. whereas the number of downlink credit resources is equal to the number of downlink CEs. and WBBPf boards in 3900 series base stations. − − UL License CE Number = UL NodeB License CE Cfg Number  Hardware-based downlink CE usage DL CE Capacity Utility Ratio = DL NodeB Mean CE Used Number/DL CE Capacity Number .DLCreditUsed. WBBPd.LC.ULCreditUsed.Mean/2) where "/2" is used because the number of uplink credit resources is twice the number of uplink CEs. and the following formula is true: UL NodeB Mean CE Used Number = VS.LC. HSDPA services do not consume CEs of R99 services in the downlink. HSUPA services and R99 services share uplink CEs.ULCreditUsed. Therefore. the NodeB manages uplink and downlink CE resources separately.NodeB.NodeB.Mean: average uplink credit resource usage of a NodeB in a cell  VS.Mean: average downlink credit resource usage of a NodeB in a cell The NodeB uses separate baseband processing units in the uplink and downlink.Mean: average uplink credit resource usage of a NodeB when CE Overbooking is enabled  VS.DLCreditUsed. the following counters are used to monitor CE usage:  VS.LC.ULCreditUsed.Mean counter is greater than 0.ULCreditUsed. the CE Overbooking feature has taken effect.Direction Rate (kbit/s) SF > minSF 2720 5760 Rate (kbit/s) SF = minSF 2720 5760 SF 2RX:Number of CEs Consumed 2RX:Corresponding Credits Consumed 4RX:Number of CEs Consumed 4RX:C Credi 2SF2 2SF2+2SF4 32 48 64 96 32 48 64 96 Table 2-3 to Table 2-8 apply only to WBBPb.LC.2 Monitoring Methods For Huawei RNCs.ULCreditUsed.Mean) DL License CE Number = DL NodeB License CE Cfg Number  License-based uplink CE usage UL License CE Resource Utility Ratio = UL NodeB Mean CE Used Number/UL License CE Number If the value of the VS.Mean/2 Otherwise. 2.10. Usages of uplink and downlink CE resources are calculated as follows:  License-based downlink CE usage − − − − DL License CE Resource Utility Ratio = DL NodeB Mean CE Used Number/DL License CE Number DL NodeB Mean CE Used Number = Sum_AllCells_of_NodeB(VS. the following formula is true: UL NodeB Mean CE Used Number = Sum_AllCells_of_NodeB(VS. ATM and IP transmission resources can be classified into physical resources. DL CE Capacity Number = VS. CE resources are limited by the license. upgrade the license file. the Iub interface can use ATM transmission or IP transmission.ULCreditAvailable The CE resource usage can be monitored by alarms. logical port resources.11 Iub Bandwidth 2. add WBBP boards.11. respectively.− − − − − The value of DL NodeB Mean CE Used Number equals that used for calculating the license-based downlink CE usage. CE resources are limited by the hardware capacity. 2. ALM-28230 Base Station Service Overload is reported. resource groups. expand capacity as follows:  If the license-based CE usage exceeds its capacity expansion threshold. In this case. 2. Depending on transmission medium.DLCreditAvailable  Hardware-based uplink CE usage UL CE Capacity Utility Ratio = UL NodeB Mean CE Used Number/UL CE Capacity Number The value of UL NodeB Mean CE Used Number equals that used for calculating the license-based uplink CE usage. . Newly added CE resources can share traffic with hotspots and relieve CE congestion caused by traffic overflow. In this step. In this case. UL CE Capacity Number = VS.HW. as shown inFigure 2-13 and Figure 2-14. select the DRA_DCCC_SWITCH andDRA_BASE_ADM_CE_BE_TTI_RECFG_SWITC H check boxes under the Dynamic Resource Allocation Switch parameter to enable the DCCC algorithm and the TTI dynamic adjustment algorithm for admission CEbased BE services.3 Optimization Suggestions If the uplink or downlink License-based or Hardware-based CE usage is constantly higher than 70% during peak hours for three consecutive days in one week. If the CE hardware capacity is exceeded. If capacity expansion is inapplicable.10. and link resources.1 Monitoring Principles The Iub interface is between the NodeB and the RNC.HW.  If the hardware-based CE usage exceeds its capacity expansion threshold. perform the following operations to optimize the CE usage:  Run the RNC command SET UCORRMALGOSWITCH.  Run the RNC command SET UUSERGBR with the Uplink GBR for BE service parameter set to D32. Figure 2-13 ATM transmission resources Figure 2-14 IP transmission resources .