CDMA forward channel carrier power varies greatly depending on how many traffic channels are in use, the characteristics of the users voices, the Forward Power Control settings as requested by each subscriber unit in use, and the power allocated for overhead functions (Pilot, Page and Sync).
An approximation of the CDMA forward channel carrier power can be defined as the power under the following conditions:
Number of Forward Links (or total Traffic Channels):
the number of traffic channels required at the 2% Blocked-Calls-Cleared (Erlang B) Grade of Service level plus the number of traffic channels that are in Soft Handoff with another cell, and/or in Softer Handoff with another sector of the same cell, i.e.,
Nfl = N(2%) x SSHOF, where SSHOF is the Soft plus Softer Handoff Factor
Traffic Channel power:
The power of the average traffic channel due to average modulation plus full rate Power Control Bits, i.e., approximately 0.15 x Ppilot for Rate Set 1, and approximately 0.27 x Ppilot for Rate Set 2
Forward Power Control:
The average Forward Power Control setting, at this setting the average traffic channel power is still approximately 0.15 x Ppilot for Rate Set 1, and approximately 0.27 x Ppilot for Rate Set 2
Overhead power:
Pilot plus Page plus Sync power is equal to Ppilot plus 0.75 x Ppilot plus 0.1 x Ppilot = 1.85x Ppilot
Since the component parts of the CDMA carrier power are all expressed in terms of Pilot power, and since Pilot power is generally determined by the site coverage requirements, we may sum this up as follows:
P(cdma) = Overhead power + Traffic Channel power
P(cdma) = 1.85 x Ppilot + Nfl x 0.15 x Ppilot (for Rate Set 1) or,
P(cdma) = 1.85 x Ppilot + Nfl x 0.27 x Ppilot (for Rate Set 2)
It must be realized that these formulas are approximations, since the power level of the Overhead components and the number and power level of the Traffic Channels continuously vary in the real world.