Breathing effect on CDMA cellular networking

An operational problem in code division multiple access (CDMA) is the breathing effect. Breathing is caused by a full cell, so users at long enough distances cannot be connected to the service and the cell appears to have become smaller. If the user numbers are less, then cell capacity becomes the previous value, so the user can be connected again, hence the cell appears to grow. There may be areas not included in a cell boundary (blank spot). In digital communication, the connection quality judgement is by comparison of energy per bit per noise gain density, a parameter known as E_b/N₀. The observed E_b/N₀ value depends on user reflection gain which is determined by the chosen channel model. The paper investigates the free space, Lee, and Hata channel propagation models.