The expansion unit consists of 4 FPGAs (xc7k160tfgg676-2) and 8 RF Transceivers (AD9370). Each FPGA has 8 optical ports, 4 of which are used to communicate with the AD9370, and 2 are used to communicate with the BS. The networking method is shown in Figure 1-1.
The optical interface that communicates with the BS has a rate of 9.8304 Gbps.
TD-LTE data select 30.72M sampling rate to transmit 20M/15M bandwidth signal, select 15.36M sampling rate to transmit 10M/5M bandwidth signal, due to support MIMO, as to transmit dual-antenna signal, an FPGA maximum support 3 carriers (30.72M*2 carriers and 15.36M*1 carriers). The TD-LTE data sampling rate is shown in the figure below:
|Carrier Bandwidth（MHz）||Sample Rate|
Figure 1-1 Carrier Sample Rate