2G Network Optimization
- 2. 2G Network Optimization Objectives Overview of Optimization Purpose of Optimization Flow of Optimization Process of Optimization 2G Main KPIs Common problem on network Solution
- 3. Optimization overview What is 2G? The second generation of cellular networks, based on the Global System for Mobile Communication (GSM). Designed to accommodate the growing number of mobile phones, GSM introduced cellular services like SMS, multimedia messaging, and digitally encrypted voice conversations. Why need Optimization? Network design. Network problem identification and resolution. Network planning for expand capacity. Network Planning to save resource.
- 4. Optimization Purpose Purpose Optimization? Ensure mobile network quality service are best for use. Optimization of growing networks to meet customer demands. Optimization to provide good quality service for current and future. Check and provide best solution for future network expand with less cost. Deployment new technology and solution to improve network needs.
- 5. Optimization Flow OPTIMIZATIO N SUMMARY PROBLEM & SOLUTION EVALUATE RESULT IMPLEMENT SOLUTION ANALYSIS & IDENTIFY PROBLEM EVALUATION OPTIMIZATION SOLUTION
- 6. ANALYSIS & INDENTIY PROBLEM OPTIMIZATION SOLUTION IMPLEMENT SOLUTION EVALUATE RESULT SUMMARY PROBLEM & SOLUTION - Collect statistics data from OSS, driving test report and result of prior actions . - Do analyze - Identify problem - Evaluation need to optimize. - Evaluate best solution for improvement and potential affect when apply solution. - Make Optimization plan detail about action and solution to ensure that network will is has improvement . Optimization Process - Collect statistics data from OSS, driving test report before and after apply solution. - Make detail report comparation before and after apply solution. - Summary all action and problem in detail to prevent problem from happened again. - Continue apply solution if network is still needs. - Prepare for next plan.
- 7. GSM Main KPIs 2G Main KPIs • SCR (SDCCH Congestion Rate) • SDR (SDCCH Drop Rate) • TCR (TCH Congestion Rate) • CSSR (Call Setup Success Rate) • CDR (Call Drop Rate) • HOSR (Handover Outgoing Success Rate)
- 8. Common Problem Common network optimization problem 1. Coverage 2. Interference 3. Congestion 4. Handover 5. Call drop
- 9. 2G Optimization Solution Reason Solution 1. Coverage 1. Blind spot 2. Overshooting 3. Overlaps 1. Adjust network parameter(RXLEV ACCESS MIN) 2. Adjust antenna and feeder 3. Increase power of TRX 4. Add new site
- 10. Phenomenon Solution 2. Interference 1. Bad voice quality 2. High call drop rate 3. Ping-pong handover 4. Handover failure 1. Reduce BTS power 2. Avoid external interference frequency 3. Adjust antenna height, azimuth, down tilt 4. Adjust frequency plan 5. Use frequency-hopping 2G Optimization Solution
- 11. Phenomenon Solution 3. Congestion (1/2) 1. Incoming handover failure 2. Low calling success rate 3. Difficult to make a call Solution-TCH congestion: 1. Adjust antenna height, direction, down tilt 2. Change BTS power 3. Adjust cell access, reselection and handover parameter 4. Open half rate function 5. Expand TRX or add new site 2G Optimization Solution
- 12. Phenomenon Solution 3. Congestion (2/2) 1. Incoming handover failure 2. Low calling success rate 3. Difficult to make a call Solution – SDCCH congestion 1. Reasonable plan LAC 2. Increase T3122 and T3212 3. Add SDCCH channel 4. Adjust cell access parameter 5. Adjust cell selection and reselection parameter 6. Check frequency interference 2G Optimization Solution
- 13. Phenomenon Solution 4. Handover (1/2) 1. Handover failure or handover success rate low 2. Frequent handover 3. Unreasonable ratio of handover in/out 1. Hardware: very high HO failure rate-work out hardware problem 2. Neighbor cell: same frequency and same BSIC for nearby cells, 3. Congestion and transmission fault: neighbor cell high load, neighbor cell TRX fault, neighbor cell transmission fault 4. Bad radio environment: check interference 2G Optimization Solution
- 14. Phenomenon Solution 4. Handover (2/2) 1. Handover failure or handover success rate low 2. Frequent handover 3. Unreasonable ratio of handover in/out 5. Coverage: no enough overlap area between source cell and target cell-improve coverage 6. Parameter setting problem: check and adjust HO parameter 7. LAC not defined in MSC: complete LAC information in MSC 8. Signaling link heavy load: A interface signaling load congestion, lead HO signaling lost-Expansion 2G Optimization Solution
- 15. Three type of call drop Solution 5. Call drop (1/2) 1. Radio link timeout: MS can not decode SACCH result in RLT timeout and dropped call 2. Handover call drop: HO failure, MS is unable to access the target cell, and can not return to the original cell as well 3. LAPD call drop: Equipment failure cause the call drop, such as LAPD link break and so on 1. Coverage: blind spot, poor indoor coverage, overshooting-adjust radio parameter, solve hardware problem. 2. Handover: unreasonable parameter, neighbor cell not complete, same BCCH&BSIC, traffic congestion-adjust parameter, balance traffic 3. Interference: adjust engineering parameter or frequency plan, open frequency hopping, solve equipment problem 2G Optimization Solution
- 16. Three type of call drop Solution 5. Call drop (2/2) 1:Radio link timeout: MS can not decode SACCH result in RLT timeout and dropped call 2.Handover call drop: HO failure, MS is unable to access the target cell, and can not return to the original cell as well 3.LAPD call drop: Equipment failure cause the call drop, such as LAPD link break and so on 4. Antenna and feeder: antenna, feeder damage, leak water; feeder mistake connection 5. Transmission: transmission break, interrupt, high BER 6. Unreasonable radio parameter: RLT, rxlev-acc- min 2G Optimization Solution