 it is extra radio power, a noise component, as far as these CDMA equations are concerned. We need to add this noise component to the equations to model the effects of forward pilots and signaling channels. Each base station puts out some amount of overhead radio power in its forward pilot and signaling channels. For each user terminal, we can regard the total received power of all the overhead channels of all the base stations as a component of its receiver noise, part of the Nu term in Eq. (28.10). Downloaded from Digital Engineering Library @ McGraw-Hill (www.digitalengineeringlibrary.com) Copyright © 2004 The McGraw-Hill Companies. All rights reserved. Any use is subject to the Terms of Use as given at the website. CDMA Principles for Multicellular Systems CDMA Principles for Multicellular Systems This makes sense from a physical perspective. Suppose that the forward pilot for an- tenna face b has transmit power t and reaches user terminal u with received power r = tGub. Then the component of noise N representing that pilot is P = r/Gub, which is just t. What we are saying here is that the model for the forward direction in the CDMA equations treats the pilot power as another interferer when we include it in the noise coefficient N. This model includes the adverse effect of having a region with several pilots with nearly equal received power competing to serve it. This effect is called pilot pollution, and it is discussed in Sec. 32.1. 28.3.2 Soft and softer handoffs A call in soft or softer handoff is using more than one forward channel. The CDMA equations present earlier do not reflect having multiple CDMA channels for one call. The areas with nearly equal radio paths are the areas in soft or softer handoff. When a call in the calculation has an alternative cell sector close to the highest radio signal path gain, the wireless telephone system almost certainly will put that call into a soft or softer handoff state and will replicate its forward signal on two antenna faces, C and d. This means that the forwar