Abstract— The optical transmission of full standard
ECMA368 OFDMUWB signals 400 Mbit/s per single user over
50 km SSMF, and the impact of optical transmission in the radio
performance experimentally analyzed in this paper.
Index Terms—Optical communication, Ultra-wide band
(UWB), access networks, fiber-to-the-home (FTTH)
I. INTRODUCTION
LTRA-WIDEBAND (UWB) wireless technology is
experiencing a fast market introduction targeting low-
cost short-range high bitrate communications (480 Mbit/s in
market-available devices, capable of 1 Gbit/s per user [1]).
UWB-on-fibre distribution in fiber-to-the-home (FTTH)
networks, was first proposed for impulse-radio and OFDM-
based UWB in [2]. UWB distribution on FTTH is an adequate
approach forward because: (i) UWB employs, in large extent,
Wimediadefined orthogonal frequency-division multiplexing
(OFDM) modulation [3], which is especially well suited for
fibre transmission impairments as chromatic dispersion,
intrachannel nonlinear distortion, and nonlinear phase noise
can be compensated [4]. (ii) UWB employs the band from 3.1
to 10.6 GHz in current regulation, so a large number of UWB
channels can be allocated on a single fiber. (iii) Is inherently a
low cost solution as UWB signals transmitted through fiber
can be received by commercial low-cost receivers.
This paper reports, by first time to our knowledge, the
impact of optical transmission of UWB signals through four
FTTH links in the performance expected by the final user after
radio transmission. The error-vector magnitude (EVM)
degradation due to optical fiber transmission, ranging between
5 and 50 km, is reported at the expected distances (03 m) in
UWB wireless applications.
II. EXPERIMENTAL SET-UP
UWB is defined as a radio modulation technique with
bandwidth (BW) larger than 500 MHz or at least with 20 %
fractional BW [5]. The experimental work herein reported
employs ECMA368 standard UWB signals [6] through
standard single mode fiber (SSMF) at typical FTTH distances.
After FTTH distribution, the UWB signal is photodetected,
amplified, and radiated to the user. Amplification is required
after photodetection to adjust the equivalent isotropic radiated
power (EIRP) to 41.3 dBm/MHz, the maximum level
allowed in current UWB regulation [5].
Fig. 1 shows the experimental set-up. The impact of
integrated UWB fiber transmission and wireless radio is
evaluated measuring the EVM at wireless distance d, after
optical transmission through different FTTH spans. The UWB
signal comprises two channels (generated by a Wisair
DV9110 module) 528 MHz BW following current regulation
[6]. Each channel bears one OFDM signal comprised by 128
carriers QPSK-modulated, 6 null carriers, and 12 pilot tones.
Each channel bitrate is 200 Mbit/s, providing an aggregated
bitrate of 400 Mbit/s per user. Each channel is centered at
3.432 GHz (Ch1) and 3.96 GHz (Ch2), respectively
Fig. 2(a). The two UWB channels are modulated on a Mach-
Zehnder electro-optical modulator (V=4.5) and transmitted
through 5, 10, 25 and 50 km FTTH links as described in
Fig. 1.
After fiber transmission the OFDM-UWB signals are
photodetected, amplified adjusting the EIRP to the regulated
level of 41.3 dBm/MHz, to generate the wireless signal.
Fig. 2(c) shows the power spectrum density (PSD) of the two
UWB channels where the degradation introduced by 25 km of
optical transmission SSMF can be observed.
Integrated performance analysis of UWB
wireless optical transmission in FTTH networks
Maria Morant, Joaquin Pérez, Marta Beltran, Roberto Llorente and Javier Marti
Nanophotonics Technology Centre, Universidad Politécnica de Valencia, Spain
{mmorant, joapeso, marbelra, rllorent, jmarti}@ntc.upv.es
U
Att
TX1
=1555nm
MZEOM
RFtoOpticalCONVERTER
(HEADEND)
PIN
L=5km,10,25km
WisairUWB
DV9110
OpticaltoRF
(1)
TX
ANTENNA
RX
ANTENNA
RADIOPROPAGATION
EVM
AgilentDSA80000B
d
OBPF EDFA
Ptx Prx
(2)
Amp#2
Amp#1
Amp#2
TX2
FTTHOPTICALTRANSMISSION
EDFA
L1=25km,L2=25km
L
L1 L2
UWBOFDMECMA368
OBPF
Fig. 1. Laboratory setup for combined performance analysis of UWB-on-fibre and further UWB wireless radio. MZ-EOM: Mach-Zehnder electro-optical
modulator; Amp: RF amplifier; OBPF: optical band-pass filter; EDFA: erbium doped fibre amplifier; Att: attenuator; PIN: positive-intrinsic-negative;
TX: transmitter, RX: receiver; DSA: digital signal analyzer.
87
MJ4
4:30 PM – 4:45 PM
978-1-4244-1932-6/08/$25.00 ©2008 IEEE