2G Network Optimization

1. 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