In TDMA, each channel is divided into several time slots, which increases that channel's data-carrying capacity. Users transmit within the confines of predetermined time slots, and channelization of users in the same band must be achieved via separation in time. In FDMA, users are assigned specific channels and have the sole right to use a channel for the entire duration of a call. CDMA is based on spread-spectrum technology, in which the original signal is distributed over a frequency much wider than the minimum bandwidth required to send that signal. All users on a 1.25MHz-wide channel can share the same frequency spectrum.
Users share time and frequency allocations, and are channeled according to unique codes.
Thus, although CDMA's low frequency renders it much slower than the technologies I'll be discussing later, this attribute also gives CDMA its wider coverage capabilities. Much of the information available on these trials and deployments is available mainly through equipment vendors involved in such projects. Solid cost information is also scant. However, some generalities can be extrapolated. The Clearwire network is made up of multiple base stations that transmit signals to subscriber facilities.