UMTS multiple access types
This tutorial on UMTS covers multiple access types used in UMTS system.
UMTS uses Direct Sequence CDMA and information is spread across bandwidth in
multiple ways as shown below, which derives different physical channels or air interfaces.
1. Information is spread across 1.6 MHz BW (1.28Mcps), referred as narrowband CDMA
2. Information is spread across 5 MHz BW (3.84 Mcps), referred as WCDMA
3. Information is spread across 10MHz BW (7.68 Mcps)
UMTS supports both FDD and TDD duplex modes. FDD is supported in 3.84Mcps option. TDD is supported in all the three options i.e. 1.28, 3.84 and 7.68 Mcps.