Slide #4

Time-Division Duplex uses only one frequency band for both uplink and downlink, and it goes alternately, depending on what time allocation will be used for both…Frequency Division Duplex uses different frequency bands for uplink and downlink.. in A third generation mobile system, CDMA is a possible choice… TDD concept can be very useful for 3rd generation mobile systems and one of the very useful concept of TDD systems is its flexibility, especially in providing asymmetric channels…. Which are suited well for multimedia services, that has different capacity requirements . the bandwidth utilisation about TDD is not fixed unlike FDD …..

Slide #13- Asymmetric channels are more easily achieved using TDD than FDD. To divide an FDD

system into asymmetric channels requires different bandwiths for the two links which must have independent filters, different data rates and perhaps equalisers…

Slide #18

- The guard times in a TDD system must accommodate the maximum round trip delay time in the cell as well as the hardware delays.

- The frame shown has a downlink capacity of 10 times that for the uplink, but the air interface is flexible and will allow extra timeslots to be added to the uplink at the expense of downlink timeslot