A fixed channel assignment plan for three-dimensional cellular system

A three-dimensional channel assignment algorithm in an indoor cellular communication system is described. The design is required to meet the objective of providing continuous communication within an area with maximum protection from adjacent interference for a given channel set and frequency reuse pattern. If this channel assignment algorithm based on a number theoretic approach is applied to two-dimensional 7-cell 21-sector channels, it becomes the channel assignment plan currently used in the US TIA (Telecommunication Industry Association) system. The channel assignment algorithm can also be applied to the code division multiple access (CDMA) system where the time/phase offset of the pseudo-random noise (PN) binary codes is used to distinguish signals received at a mobile station from different base stations. A method that can easily estimate the time/phase offset from the received PN code with respect to the receiver-stored replica of the PN code is described