Handbook

ClearFill Star CDMA
1100187 Rev. 1.0
Page 23 of 152
3 System Design Guidelines
3.1 CDMA Basics (in preparation)
3.1.1 Data (in preparation)
3.1.2 Voice (in preparation)
3.2 Required information for system design
A successful and reliable RF-design is based on many different parameters and assumptions
and cannot be described completely in this handbook. The goal of indoor system design is to
meet the requirements for excellent performance and QoS.
Understanding requirements should include, but not be limited to:
 Capacity vs. coverage
 Current and future needs
 Timeline for implementation
 Customers expectation
The essential key information for a proper system design:
 Coverage area
 Building details
 Expected traffic
 Frequency plan
o Pilot pollution issues
o Carrier to Interference Ratio
3.2.1 Power level
A main parameter for the system design is the required signal strength level.
The minimal required signal strength level should be selected in accordance to the on site
conditions. There are several parameters to take into consideration.
Typical values for the min. required signal strength level are in the range of -80dBm to -
85dBm for Common Pilot Channel (CPICH).
Other present cells (usually strong outdoor cells) may require to increase the signal strength
level at least 10dB (-70 to-75dBm for CPICH).
In CDMA systems, the indicated minimum signal strength level refers to the CPICH,
representing the most important parameter for the RF-designer. It is essential for a proper
connection that the mobile can receive a dominant CPICH; otherwise poor quality of service
occurs (QoS).
Poor QoS results in dropped calls, poor voice quality and poor data throughput.
High signal strength level needs more active equipment resulting in higher costs for the
system.