Time Division Multiple Access (TDMA)

Time Division Multiple Access (TDMA) TDMA - INTRODUCTIONTime Division Multiple Access (TDMA) is a technology used in digital cellular telephone communication that divides each cellular channel into three time slots in order to increase the amount of data that can be carried. TDMA INTRODUCTION cont...TDMA improves spectrum capacity by splitting each frequency into time slotsIt also allows each user to access the entire radio frequency channel for the short period of a call.The base station continually switches from user to user on the channel. It is the dominant technology for the second generation mobile cellular networks.TDMA - HOW TDMA WORKSTDMA relies upon the fact that the audio signal has been digitized; that is, divided into a number of milliseconds-long packets. It allocates a single frequency channel for a short time and then moves to another channel. The digital samples from a single transmitter occupy different time slots in several bands at the same time.TDMA - HOW TDMA WORKS cont...

All stations transmit data on same frequency, but at different times

- Needs time synchronizationTDMA - APPLICATIONSi) TDMA in mobile phone systems2G systems : Most 2G cellular systems, are based on TDMA. GSM,D-AMPS, PDC, iDEN, andPHSare examples of TDMA cellular systems.

3G systems : Although most major 3G systems are primarily based uponCDMA, time division duplexing (TDD), packet scheduling (dynamic TDMA) and packet oriented multiple access schemes are available in 3G form, combined with CDMA to take advantage of the benefits of both technologies.

TDMA - APPLICATIONSii) TDMA in wired networks- TheITU-TG.hnstandard, which provides high-speed local area networking over existing home wiring (power lines, phone lines and coaxial cables) is based on a TDMA scheme.- FlexRay protocol which is also a wired network used for safety-critical communication in modern cars, uses the TDMA method for data transmission control.TDMA - PROS AND CONSProsusers can be given different amounts of bandwidthmobiles can use idle times to determine best base stationcan switch off power when not transmittingConssynchronization overheadgreater problems with multipath interference on wireless links "dead time" between time slots limits the potential bandwidth of a TDMA channel.