ZTE Corporation CBTSI18A Manuale Utente
Chapter 2 - BTS Hardware
Confidential and Proprietary Information of ZTE CORPORATION 31
RFS Schematic Diagram
Located between BDS and MS (Mobile Station), RFS connects to the BDS
through a data interface and to the MS through the air RF interface. Its
through a data interface and to the MS through the air RF interface. Its
working principle is shown in Fig. 7.
F
I G
. 7
R F S S
C H E M A T I C
D
I A G R A M
Ctl-Bus
& clk
Rev.Link
Fwd.Link
......
......
Rev.Link
Rev.Link
......
Co
n
tr
o
l
B
u
s
&
lk
RFS
......
Control Bus & Clk
BDS
RFE
RFE
PA
PA
BTM
Combin/TSM/RSM
TRX
TRX
TRX
RMM
Functions of RFS are:
TRX: performs signal up- and down-frequency conversion.
RMM: Connects RFS and BDS.
LPA: performs signal power amplification on the forward link.
RFE: performs low noise amplification, being the interface between RFS
and the antenna feeder.
BTM: performs the radio test for the BTS.
PIM: works as the interface of power amplifier.
RFS Working Principle
Call processing flow in RFS is as follows.
In the forward link, the data stream from the BDS converges in RMM
and then is distributed to TRX. The stream in TRX changes to
intermediate frequency (IF) signals first and then goes to RFE for up-
intermediate frequency (IF) signals first and then goes to RFE for up-
conversion. The RF signals generated are finally transmitted through
RFE and antenna feeder after power amplification.
RFE and antenna feeder after power amplification.