-
[show abstract]
[hide abstract]
ABSTRACT: This paper reports a new simulation method using software based
millimeter-wave test bed that has been developed to emulate a wide range
of millimeter-wave communication concepts in the
hardware-in-the-loop-simulations and to evaluate an advanced signal
processing algorithm for the high speed communication. The system
description of the test bed architecture and the implementation of a
millimeter-wave transceiver of 38 and 60 GHz are presented. To evaluate
the test bed performance, the BERs and the constellations are measured
Radio and Wireless Conference, 1999. RAWCON 99. 1999 IEEE; 02/1999
-
[show abstract]
[hide abstract]
ABSTRACT: In this paper, 60 GHz indoor broadband wireless channels are
measured with various configurations in a typical office environment.
Measurements are taken at nine positions of the room and the
base-station antenna is placed either at the center or at an edge of the
measurement room, and the remote-station antenna is of either sharp beam
or broad beam type. The RMS delay spread (RDS) and normalized received
power (NRP) are estimated from the measurements. Statistical models of
the 60 GHz indoor wireless channels are also presented with model
parameters from the measured channel data based on the Saleh's (1987)
indoor channel modeling method. Bit error rate (BER) simulations are
performed using measured and simulated channel impulse responses with
DQPSK-OFDM modulation, respectively. Using sharp beam antenna results in
superior performances to using broad beam antenna in terms of both bit
error rates (BER) and NRP penalty. Also, placing the base-station
antenna at the center is superior to placing it at an edge in terms of
BER and NRP
Personal, Indoor and Mobile Radio Communications, 1998. The Ninth IEEE International Symposium on; 10/1998
-
[show abstract]
[hide abstract]
ABSTRACT: We propose a novel nonlinear model and a nonlinear equalizer for
high density magnetic recording channels. The model is based on the
superposition of data transition dependent pulses. The proposed
nonlinear equalizer utilizes the proposed nonlinear model. When tested
with actual read back signals, the model using 2 and 32 pulses achieved
gains of 4.6 dB and 29.4 dB, respectively, over the linear model. Also
the proposed nonlinear equalizer attained a gain of 1.5 dB over the
RAM-DFE at a bit error rate of 1E10<sup>-</sup>6 when the nonlinear
signal was generated by a finite state machine model
Communications, 1998. ICC 98. Conference Record.1998 IEEE International Conference on; 07/1998
-
[show abstract]
[hide abstract]
ABSTRACT: Nonlinear distortions, which limit detector performance at high
recording densities, are known as the nonlinear transition shift and
partial erasure. The nonlinear transition shift is known to be reduced
substantially by the precompensation technique, while the partial
erasure requires sophisticated nonlinear equalization techniques. In
this paper, a new calculation intensive adaptive technique is presented
that uses stochastic gradient method to minimize the mean squared error
between actual playback signal samples and modeled signal samples. The
effectiveness of the proposed adaptive approach to separately estimate
these two nonlinear parameters uniquely is demonstrated by computer
simulation
IEEE Transactions on Magnetics 02/1998; · 1.36 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: In this paper, the convergence behavior of the timing phase when
an adaptive partial response equalizer and a decision-directed type of
phase-locked loop (PLL) are used together in the tracking mode for a
digital recording channel is described. The phenomenon of bias in the
timing phase when the convergence parameter of the adaptive partial
response equalizer and the timing recovery constant of the PLL are not
selected properly is introduced. The phenomenon, occurring due to the
combining effect of two tracking algorithms for the adaptive equalizer
and the PLL are investigated, by computer simulation, and the region of
convergence for timing phase recovery is discussed. Also, a method to
overcome the phenomenon using a variable step-size parameter is
described
Global Telecommunications Conference, 1996. GLOBECOM '96. 'Communications: The Key to Global Prosperity; 12/1996
-
[show abstract]
[hide abstract]
ABSTRACT: This paper compares performances of several linear and nonlinear equalization/detection methods for magnetooptical storage channels. The simulation data sets with linear and nonlinear distortion are generated based on the measured characteristics of a real magneto-optical disk, in which the data is (1,7) run-length limited coded and recorded in NRZI format. For linear signals, FDTS/DP of depth 3 has the lowest bit error rate. For nonlinear signals, the nonlinear detection methods for fixed delay tree search with decision (FDTS/DF) and multilevel decision feedback equaliser (MDFE) using look-up table achieve a significant improvement in performance over the linear methods. For PRML (partial response maximum likelihood) with PR II, however, the minimum run length constraint is the most dominant factor for the performance for both linear and nonlinear signals
Communications, 1995. ICC '95 Seattle, 'Gateway to Globalization', 1995 IEEE International Conference on; 07/1995
