FDMA-TDMA-CDMA: An Introduction By Dr. Ernest Simo 4.0 CODE DIVISION MULTIPLE ACCESS In Code Division Multiple Access or CDMA strategies, we create yet another Dimension (in addition to the Frequency and Time dimensions). This new, orthogonal dimension is referred to as the Code Dimension ©. Given a wideband slice of the total bandwidth B, our focus will now be placed on the newly created Code Dimension: Here several users are allowed, "at all times", to access the broadband Frequency slice. However, each user must employ a unique Code (Ci). Since co-users are isolated by codes rather than Frequencies, the ability to reuse frequencies is very high. This further enhances the overall spectral efficiency. If these codes are orthogonal, they will isolate the users in the Code Dimension. (Just like different frequencies and different Time-Slots do in the Frequency and Time Dimensions respectively.) FDMA-TDMA-CDMA: AN INTRODUCTION By Dr. Ernest Simo © 1999 DR. ERNEST SIMO - SPACE2000