- 3 A The Umts Utra Tdd Uu Radio Interface Diagram Is Shown In Fig 3 Where The Chipping Rate Is Fixed At 3 84mchip S A 1 (93.21 KiB) Viewed 11 times
all the questions.
3. a) The UMTS UTRA-TDD Uu radio interface diagram is shown in Fig.3, where the chipping rate is fixed at 3.84Mchip/s, and the radio frame with a time duration of 10ms contains 38,400 chips. The radio frame consists of 15 time slots, each of which has 2,560 chips and a time duration of 666.7μs. Five different spreading factors including 1,2,4,8 and 16 can be used to satisfy various bandwidth requirements. Based on Fig.3 and assuming the lowest signal modulation format is used, answer the following five questions: i) If a TDD radio frame has 10 time slots for downlink transmission and 5 time slots for uplink transmission. Work out the minimum net signal bit rates for both downlink and uplink. [3+3=6] ii) For each uplink connection, maximum five channels may be made available to a single user. Work out the maximum theoretical net signal bit rate offered to the user. iii) If a user would like to upload a file at a speed of 0.4Mb/s, work out the spreading factor that the user may choose, and identify the corresponding net signal bit rate associated with the chosen spreading factor. [4] iv) Under the fixed chipping rate of 3.84Mchip/s, state the relationship between the bandwidths of various signals produced using different spreading factors. [3] v) Assuming the chipping rate is proportional to spreading factor, state the bandwidth relationships between various signals produced using different spreading factors. [3] Radio frame 10 ms 0 1 2 12 13 14 Time slot Midample Data 256 chips 1104 chips 2560 chips Fig.3 666.7 µs Data 1104 chips GP Traffic burst GP: guard period 96 chips