On the Erlang capacity of CDMA cellular systems

In FDMA and TDMA cellular systems, a requested call will be blocked when all frequency or time slots have been assigned to other users. In a CDMA cellular system, blocking will occur when the reverse link multiple access interference power reaches a predetermined level which is set to maintain acceptable signal quality. The number of users for which the CDMA blocking probability equals a certain value (usually 1% or 2%) is defined to be the "Erlang capacity" of the system and is related to an equivalent number of channels in an FDMA or TDMA cellular system. In this paper, the calculation of the CDMA blocking probability is based on a new analysis of the total squared power of other-cell interference. The calculation of CDMA Erlang capacity based on this result gives a result that is higher than that given in previous analyses.