![]() Operational limits and quality issues will reduce the maximum number of calls somewhat lower than this value. There are 64 Walsh codes available to differentiate between calls and theoretical limits. ![]() How Does CDMA Work?ĬDMA allows up to 61 concurrent users in a 1.2288 MHz channel by processing each voice packet with two PN codes. Using a group of codes, which are orthogonal to each other, it is possible to select a signal with a given code in the presence of many other signals with different orthogonal codes. A code called spreading code is used to perform this action. Here, a signal is generated which extends over a wide bandwidth. Techniques generally used are direct sequence spread spectrum modulation (DS-CDMA), frequency hopping or mixed CDMA detection (JDCDMA). The basic principle is that different CDMA codes are used to distinguish among the different users. In this system, a user has access to the whole bandwidth for the entire duration. CDMA OverviewĬode Division Multiple Access system is very different from time and frequency multiplexing. ![]() ![]() The technology is commonly used in ultra-high-frequency (UHF) cellular telephone systems, bands ranging between the 800-MHz and 1.9-GHz. ![]() It optimizes the use of available bandwidth. Code Division Multiple Access (CDMA) is a sort of multiplexing that facilitates various signals to occupy a single transmission channel. ![]()
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