

Type of Document Dissertation Author Cameron, Rick A. URN etd-23349150973140 Title Fixed-Point Implementation of a Multistage Receiver Degree PhD Department Electrical and Computer Engineering Advisory Committee
Advisor Name Title Brian Woerner Committee Chair Hugh VanLandingham none Jeffrey H. Reed none John Kobza none Theodore Rappaport none Keywords
- interference cancellation
- quantization
- synchronization
- CDMA
Date of Defense 1997-01-13 Availability unrestricted Abstract This dissertation provides a study of
synchronization and quantization issues in
implementing a multistage receiver in
fixed-point Digital Signal Processing (DSP)
hardware. Current multistage receiver analysis
has neglected the effects of synchronization
and quantization; however, these effects can
degrade system performance and therefore
decrease overall system capacity.
The first objective is to analyze and simulate
various effects of synchronization in a
multistage system. These effects include the
effect of unsynchronized users on the bit error
rate (BER) of synchronized users, and
determining whether interference cancellation
can be used to improve the synchronization
time. This information is used to determine
whether synchronization will limit overall
system capacity. Both analytical and
simulation techniques are presented.
The second objective is to study the effects of
quantization on the performance of the
multistage receiver. A DSP implementation of
a practical receiver will require a DSP chip
with a fewer number of bits than the computer
chips typically used in simulation of receiver
performance. Therefore, the DSP
implementation performs poorer than the
simulation results predict. In addition, a
fixed-point implementation is often favored
over a floating-point implementation, due to
the high processing requirements necessitated
by the high chip rate. This further degrades
performance because of the limited dynamic
range available with fixed-point arithmetic.
The performance of the receiver using a
fixed-point implementation is analyzed and
simulated.
We also relate these topics to other important
issues in the hardware implementation of
multistage receivers, including the effects of
frequency offsets at the receiver and
developing a multiuser air protocol interface
(API). This dissertation represents a
contribution to the ongoing hardware
development effort in multistage receivers at
Virginia Tech.
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