CDMA Spectral EfficiencyEnhancing the most secured system
CDMA Technology
CDMA – “Most secured”
Fast growing rate of CDMA subscribers
Evolution of Ev-DO technology in year 2000
Need of spectral efficiency using 1X advance features.
Spectral Efficiency techniques
Network Handset 4GV Vocoders Transmit diversity in Base
Station New Radio Configuration 4-way receive diversity in
Base Station Quasi orthogonal functions 1/8th rate gating on R-FCH RL interference cancellation
4GV Vocoders Receive diversity in mobile
terminals Quasi orthogonal functions New Radio Configuration Quasi-linear interference
cancellation in mobiles Enhanced FL interference
cancellation 1/8th rate gating on R-FCH
Quasi-Linear interference cancellation (QLIC) Pilot consumes sizable
amount of power .
Interference is common.
Important to initialize Pilot Interference Cancelation (PIC) and forward link interference cancelation (FLIC).
Reverse Link Interference cancellation (RLIC)
Reverse link interference cancellation equally important.
Mobile transmits less power .
Increase the battery life.
1/8 rate Gating on R-FCH
It is put “ON” at MSC level MS will gate the R-FCH/R-Pilot Channel when
transmitting at 1/8th rate. Power control factor is achieved
4GV Dynamically prioritize voice quality to increase
network capacity EVRC-B is an enhancement to EVRC Used both at the network as well as in the handset.
Radio Configuration Set of forward traffic channel and reverse traffic
channel Physical layer parameters such as data rates,
modulation characteristics, and spreading rates.
Quasi-Orthogonal functions (QOF) Increasing of the number of users.
Walsh code is limited for much possible users.
QOF process optimal cross-correlation with Walsh code
6 Sectorization Some places with high utilization and
excess softer handoff.
6 sector s one of the solution.
Instead of using 1 BTS, 2 BTS are used
Antenna can be separated from each other at 60 degrees instead of 120 degrees.
Network Optimization
Ec/Io optimization
Forward and reverse link imbalance
Excessive soft handoff areas
Improper RF parameters settings
Use repeaters for low utilized sectors
Antenna Diversity Improve the quality of a wireless link Mitigate these multipath situations Using multiple antennas decreases the number of
drop-outs and lost connections
Conclusion
A growth of 375% in the traffic capacity. 120 active users per carrier, per sector. Spectral efficiency takes place.
Increase in the traffic capacity
Thank You