Research Inventy : International Journal of Engineering and Science
Multiuser Pre-equalization for Pre-Rake DS-UWB Systems
1. Design of Multiuser Pre-Rake
Systems for Reliable
Ultra Wideband
Ultra-Wideband Communications
ZAHRA AHMADIAN
MICHAEL B. SHENOUDA
LUTZ LAMPE
2. Overview
I t d ti
Introduction to P R k UWB
t Pre-Rake
System Model
Problem Formulation
Convex Problem Formulation
Results
Conclusion
3. Introduction to Pre-Rake UWB 1/2
Traditional Rake Receiver
Pre-Rake Transmission
P E
Pre-Equalized P R k
li d Pre-Rake
4. Introduction to Pre-Rake UWB 2/2
MISO Pre-Equalized Pre-Rake (Torabi et al. 2009)
Multiuser MISO Pre-Equalized Pre-Rake
5. System Model
Transmitter Receiver
• Multiple Antenna Central transmitter • Single Antenna Receiver
• Pre-Equalizing Filter • De-Spreading Filter
• Up Sampler • Down Sampler
• Spreading Code • Equalizing Gain
• Pre-Rake Filter • Demodulator
6. System Model
Channel impulse responses generated according to
802.15.4a
802 15 4a model
Discrete time baseband channel impulse response
root-raised cosine pulse shaping filters
p p g
12. Results 3/3
350
= 0 08 CM2
0.08
300
= 0.10 CM2
= 0.08 CM6
= 0.10 CM6
250
# of channels with < X
200
150
f
100
50
0
5 10 15 20 25 30 35 40
X [dB]
13. Conclusion
We have proposed the use of multiuser pre-equalization
filters to mitigate the effect of ISI and MUI.
We have formulated the filter optimization problem
pertinent for the operation of such UWB systems
systems.
We have shown that this problem is equivalent to a convex
QCQP problem
The numerical results illustrated the efficacy of multiuser
pre-equalization to achieve quality of service constraints
with a minimal power budget
budget.
Future work
• Design of multiuser pre-equalization filters subject to
pre equalization
spectral mask constraints.