Parameter check list in Huawei System for high TCH Drops.

What is Call Drop? The TCH call drop rate refers to the ratio of call drops to successful TCH seizures after the BSC successfully assigns TCHs to MSs. The TCH call drop rate can be measured from the following aspects: TCH call drop rate (including handover) TCH call drop rate (excluding handover) Formulas for Call Drop including handovers: TCH call drop rate (including handover) = Number of call drops on TCH/(Number of successful TCH seizures (signaling channel) + Number of successful TCH seizures (TCH) + Number of successful TCH Seizures in TCH handovers (TCH)) x 100% Formulas for Call Drop excluding handovers: TCH call drop rate (excluding handover) = Number of call drops on TCH/Number of successful TCH seizures (TCH) x 100% Parameter Check list for Call Drop: These parameters are common for all the vendors the only difference is its name will be different. The settings of some parameters on the BSC and MSC sides may affect the TCH call drop rate. If the following situations occur, the TCH call drop rate may increase: 1. The parameters SACCH Multi-Frames and Radio Link Timeout are set to too small values. 2. The parameter RXLEV_ACCESS_MIN is set to a too small value. 3. The parameter RACH Min.Access Level is set to a too small value. 4. The parameters Min DL Power on HO Candidate Cell and Min Access Level Offset are inappropriately set. 5. The length of timer T3103 (this timer is set to wait for a Handover Complete message) is set to a too small value. 6. The length of timer T3109 (this timer is set to wait for a Release Indication message) is set to a too small value. 7. The length of timer T3111 (this timer specifies the connection release delay) is set to a too small value. 8. The length of timer T305/T308 is set to an invalid or too great value. 9. The parameter TCH Traffic Busy Threshold is set to a too small value. 10. The parameter Call Reestablishment Forbidden is set to Yes. 11. The parameters related to edge handover are inappropriately set. 12. The parameters related to BQ handover are inappropriately set. 13. The parameters related to interference handover are inappropriately set. 14. The parameters related to concentric cell handover are inappropriately set. 15. The parameters related to power control are inappropriately set. 16. T200 and N200 are set to too small values. 17. Some neighboring cell relations are not configured. 18. The parameter MAIO is inappropriately set. 19. The parameter Disconnect Handover Protect Timer is set to a too small value. 20. The parameter TR1N is set to a too small value. 21. The parameters Software Parameter 13 and MAX TA are set to too small values. 22. If a repeater is used, the parameter Directly Magnifier Site Flag is set to No.

Coverage problem troubleshooting

Troubleshooting Process of Coverage Problems: In case of coverage problems, the onsite engineers can do as follows to handle the problems: 1. Analyze the hardware configuration, parameter settings, traffic statistics, and alarms. 2. Check the BTS hardware, test the TRX power and the transmit power on top of the cabinet, and perform drive tests on site. 3. Communicate with the customer that makes the complaints and perform field tests.Then, most coverage problems can be solved. 4. Check the hardware configuration: Check whether capacity expansion is performed and whether the combination mode changes according to the TRX configuration provided by the customer. Checking the hardware configuration helps determine whether a TRX is faulty or whether the TRXs are sufficient, because the number of TRXs may be smaller than that before network replacement, which leads to congestion and traffic decrease. 5. Check the parameter settings: Check the PDCH configuration and settings of the parameters closely related to the coverage, such as Power Class (0), RACH Min.Access Level (≤1), RXLEV_ACCESS_MIN, and Cell Layer (same as the layer of the neighboring cell). In addition, check the configuration of the neighboring cell relations. Cells in the same BSC should be configured as bidirectional neighboring cells; cells between different BSCs should be configured as external neighboring cells. Note that the serving cell should be configured as the neighboring cell of other cells. 6. Check the alarms and traffic statistics: > The coverage-related alarms are generated mainly because the TRX is faulty. i) Hardware alarms: LAPD alarm, TRX configuration alarm, TRX processor running Alarm, radio link critical alarm, TRX power decrease alarm, TRX power amplifier shutdown alarm, TRX voltage abnormal alarm, TRX hardware alarm, TRX VSWR alarm, TRX board communication alarm, CDU level-1 VSWR alarm, and CDU level-2 VSWR alarm. ii) Clock alarms: clock reference abnormal alarm, frame or TS number alarm, TRX clock major alarm, phase-locked loop critical alarm, and TMU clock alarm. iii) Transmission alarms: LAPD OML fault alarm, E1 remote alarm, and E1 local alarm. The preceding alarms do not necessarily cause the coverage decrease; however, if alarms are generated and cleared frequently, the coverage seems to be poor and the signal seems to fluctuate for the customer. In problem identification, handle these alarms first. > The measurement counters are related to KPI Measurement per Cell, Incoming/Outgoing Internal/External Inter-Cell Handover Measurement per Cell, Measurement of Power Control Messages per Cell, Receive Quality Measurement per TRX, and Uplink-and-Downlink Balance Measurement per TRX. i) Compare the number of SDCCH requests and the number of TCH requests respectively before and after network replacement to check whether the number of SDCCH requests and the number of TCH requests during paging response are normal. ii) Check whether congestion occurs according to the congestion rate. If the congestion rate is high, access to the network becomes difficult, thus causing complaints. iii) Compare the traffic volume in busy hours before and after network replacement to check whether the traffic volume decreases. Traffic volume is an important indicator of the coverage. iv) Compare the number of incoming inter-cell handovers and the number of outgoing inter-cell handovers respectively before and after network replacement to check whether the cooperation with the neighboring BTS is normal. v) Check the average receive level and the average receive quality in the uplink and the downlink. 7. Compare the drive test data before and after network replacement: This method is effective to solve the coverage problem and can provide valid evidence for coverage decrease. If network replacement is performed by the customer, the drive test data before network replacement may be unavailable; therefore, identifying the coverage problem becomes more difficult. You can perform drive tests after network replacement and check the BTS to identify the problems such as reverse connection of the feeder, poor coverage of the antenna, and handover failure. In addition, you need to communicate with the customer that makes the complaints and perform field tests to obtain the firsthand data for future comparison. 8. Check the BTS antenna and feeder: With the drive test results, check the antenna and feeder connections. If the drive test results show that the antenna coverage is poor, use the SITEMASTER to test whether the VSWR is smaller than 1.5. If the VSWR is greater than 1.5, check whether water runs into the antenna connector or feeder connector and whether the surge protector is faulty. If there are complaints about poor coverage after network replacement but the drive test results show that the coverage is normal, the poor coverage in some areas may be concerned with the antenna, especially the omnidirectional antenna, of the main BCCH changes, or the tilt or azimuth angle of the antenna changes. If the TMA is installed, you need to check whether the TMA is activated and functional. 9. Test the transmit power on top of the cabinet: Ensure that the cables are securely connected. Then, check whether the transmit power on top of the cabinet is normal. If the transmit power is abnormal, use a power meter to check the power of the TRX and combiner. If the TRX power decreases or the combiner loss is too high, replace the faulty TRX or combiner. The receiver sensitivity can be tested by only the CMD57, which is unavailable on site. Therefore, you can replace the faulty TRX. 10. Find out other causes: insufficient coverage, interference, poor electromagnetic environment, MS fault, SIM fault, or mistaken complaints due to the surrounding environment of the antenna, building in the cell, vegetation in the cell, transmission model, and emergence of new hotspot areas.

Which Parameters helps to reduce TCH Congestion Rate?

Below mentioned parameters may cause TCH Congestion & also help you to reduce TCH Congestion: 1. TCH Traffic Busy Threshold(%) 2. RXLEV_ACCESS_MIN 3. SACCH Multi-Frames and Radio Link Timeout 4. SDCCH Dynamic Adjustment 5. RACH Min.Access Level 6. Speech Version 7. TCH Immediate Assignment 8. Speech Version 9. Fix Abis Prior Choose Abis Load Threshold 10. Assignment Cell Load Judge Enable 11. Flex Abis Prior Choose Abis Load Threshold 12. Directed Retry Load Access Threshold 13. Balance Traffic Allowed 14. Load HO Allowed 15. Load HO Step Period 16. Load HO Step Level 17. Cell Direct Try Forbidden Threshold 18. Direct Retry 19. SDCCH Dynamic Adjustment 20. Direct Retry and Cell Direct Try Forbidden Threshold 21. AMR TCH/H Prior Allowed 22. T3103 23. T3107 24. F2H HO th/ H2F HO th 25. Maximum Ratio Threshold of PDTCH

How to deal with clock abnormal alarm without frequency meter in HUAWEI SYSTEM

Many times we are getting "Abnormal Clock Frequency" alarm in our system, find herewith troubleshooting of this alarm in HUAWEI System without frequency meter. Log on LMT and choose the site has clock abnormal alarm Right click its GTMU board , choose maintain clock Click on query, you can see some information, one is trace mode Right click “trace mode”, choose “setting clock” In trace mode, choose “disable trace range limit” and click set. Query again, you can see : trace mode is disable trace range limit After click set, query board information In clock state, now it’s capture, we need to wait until “locked”, it lasts about 30 mins or more,1h,2h,……….. After clock state is locked, do step 5 again, we can get the current value of clock ,remember the current value number. In trace mode, choose “enable trace range limited” ; Click “ set calibration value “ Write the calibration value with the same current value. At last, click set. Query again. Step 3 Make sure the clock abnormal alarm is cleared and feedback the 3 value : product value , current value , adjust value

The simple truth about LTE

What is LTE? LTE stands for Long Term Evolution and it represents the next step in mobile radio communications after HSPA. 3GPP is the standardization body behind LTE.Another name for LTE is e-UTRA (Evolved-UMTS Terrestrial Radio Access). LTE is expected to be the most competitive radio technology in coming years by offering high-data-rates with low-latency, improving services, lowering the costs and allowing for spectrum refarming thanks to the frequency and bandwidth flexibility. Some main aspects of LTE are: Peak data rate of 50 / 100 Mbps (uplink 2.5bit/s/Hz / downlink 5bit/s/Hz) Reduced latency enabling RTT (round trip time) <10 ms Packet-optimized Improved spectrum efficiency between 2- 4 times higher than Release 6 HSPA Frequency flexibility: standard defines 15 FDD and 8 TDD operating bands Bandwidth scalability with allocations of 1.4, 3, 5, 10, 15 and 20 MHz Operation in FDD and TDD modes Support for inter-working with UMTS and non-3GPP systems (i.e. WiMAX) Good level of mobility: optimized for low mobile speeds (up to 15km/h) but support also high mobile speeds (up to 350km/h) Improved terminal power efficiency

3G vs. 4G Wireless - What is the Difference?

3G is currently the world’s best connection method when it comes to mobile phones, and especially mobile Internet. 3G stands for 3rd generation as it is just that in terms of the evolutionary path of the mobile phone industry. 4G means 4th generation. This is a set of standard that is being developed as a future successor of 3G in the very near future. The biggest difference between the two is in the existence of compliant technologies. There are a bunch of technologies that fall under 3G, including WCDMA, EV-DO, and HSPA among others. Although a lot of mobile phone companies are quick to dub their technologies as 4G, such as LTE, WiMax, and UMB, none of these are actually compliant to the specifications set forth by the 4G standard. These technologies are often referred to as Pre-4G or 3.9G. 4G speeds are meant to exceed that of 3G. Current 3G speeds are topped out at 14Mbps downlink and 5.8Mbps uplink. To be able to qualify as a 4G technology, speeds of up to 100Mbps must be reached for a moving user and 1Gbps for a stationary user. So far, these speeds are only reachable with wired LANs. Another key change in 4G is the abandonment of circuit switching. 3G technologies use a hybrid of circuit switching and packet switching. Circuit switching is a very old technology that has been used in telephone systems for a very long time. The downside to this technology is that it ties up the resource for as long as the connection is kept up. Packet switching is a technology that is very prevalent in computer networks but has since appeared in mobile phones as well. With packet switching, resources are only used when there is information to be sent across. The efficiency of packet switching allows the mobile phone company to squeeze more conversations into the same bandwidth. 4G technologies would no longer utilize circuit switching even for voice calls and video calls. All information that is passed around would be packet switched to enhance efficiency. Summary: 1. 3G stands for 3rd generation while 4G stands for 4th generation 2. 3G technologies are in widespread use while 4G compliant technologies are still in the horizon 3. 4G speeds are much faster compared to 3G 4. 3G is a mix of circuit and packet switching network while 4G is only a packet switching network

What is Paging Flow Control?

Paging Flow Control is alarm triggered in Ericsson MSC when PCH load is high. Paging flow control alarm for a LAI at the Ericsson MSC At that time Problem in Terminated Calls.Originating calls have no problems. Also notice that a lot of discarded pages due to full paging queue but zero or very few discarded pages due to old paging messages. Solution:LAI split is good solution and also check SDCCH congestion after LAI splitting. Also Check Different value of MFRMS? MFRMS RELATED TO PAGING GROUPS FOR NCOMB Paging Group=(9-AGBLK)*MFRMS FOR COMB Paging Group=(3-AGBLK)*MFRMS