Rohde & Schwarz R&S FSL3 - Introduction; Signal Processing Block Diagram

R&S FSL WiMAX, WiBro Measurements (Options K92/K93)
1300.2519.12 2.155 E-11
Introduction
The following description provides a brief overview of the digital signal processing used in the IEEE
802.16 OFDMA measurement application.
From the received IF signal as the point of origin to the actual analysis results like EVM or CINR, the
digital signal processing can be divided into four major groups:
napplicatio tmeasuremenOFDMA
Analysis
onequalizati /estimation Channel
ationSynchroniz
capturing Data
3
4
3
5
6
•
•
•
•
The description of the IEEE802.16–2005 OFDMA/WiBro measurement signal processing is structured
accordingly.
Signal Processing Block Diagram
pow er
detection
window
subfram e
detection
window
f
re q u e n c y
com pensation
coarse
c h a n n e l e s t.
(
pream ble)
fin e tim in g
FFT
coarse
c h a n n e l e s t.
(p ilo ts )
equalizer
a n d s y m b o l
decision
M U X
MUX
fin e
c h a n n e l e s t.
(s y m b o ls )
I/Q -im b a la n c e
estim ation
equalizer
fu ll
com pensation
u s e r d e fin e d
com pensation
tra c k in g
estim ation
SFO
re s . C F O
analysis
s
ubcarrier
selection
D
f
c
oarse

I/Q -d a ta
(c a p tu re b u ffe r)
i
coarse

i
fine

H
pream ble

H
fine

H
pilots

H
pream ble

a
l
,k

D Q

re fe re n c e p a th
m
e a s u re m e n t p a th
c a rrie d o u t tw ic e
fo r U L s u b fra m e s
r
l
,k
r
l
,k
'
r
l,k
''
r
l,k
'''
CPE
gain
Fig. 2-93 Signal processing of the IEEE 802.16 OFDMA measurement application
The block diagram in Fig. 2-93 shows the OFDMA measurement application from the capture buffer
containing the I/Q data to the actual analysis block. Outcome of the fully compensated reference path
(green) are the estimates
kl
a
,
ˆ
of the transmitted data symbols
kl
a
,
. Depending on the user defined
compensation, the received samples
kl
r
,
2
2
2
of the measurement path (orange) still contain the transmitted
signal impairments of interest. The analysis block reveals these impairments by comparing the
reference and the measurement path. Prior to the analysis, diverse synchronization and channel
estimation tasks have to be accomplished.