TY  - JOUR
T1  - Adaptive frequency-domain equalization and diversity combining for broadband wireless communications.
JF  - IEEE Journal on selected areas in communications
A1  - Clark, M.V
LA  - English
UL  - https://tuklas.up.edu.ph/Record/UP-99796217609332982
AB  - We introduce a new kind of adaptive equalizer that operates in the spatial-frequency domain and uses either least mean square (LMS) or recursive least squares (RLS) adaptive processing. We simulate the equalizer's performance in an 8-Mb/s quaternary phase-shift keying (QPSK) link over a frequency-selective Rayleigh fading multipath channel with ~3 μs RMS delay spread, corresponding to 60 symbols of dispersion. With the RLS algorithm and two diversity branches, our results show rapid convergence and channel tracking for a range of mobile speeds (up to ~100 mi/h). With a mobile speed of 40 mi/h, for example, the equalizer achieves an average bit error rate (BER) of 10 -4 at a signal-to-noise ratio (SNR) of 15 dB, falling short of optimum linear receiver performance by about 4 dB. Moreover, it requires only ~50 complex operations per detected bit, i.e., ~400 M operations per second, which is close to achievable with state-of-the-art digital signal processing technology. An equivalent time-domain equalizer, if it converged at all, would require orders-of-magnitude more processing
KW  - BER.
KW  - LMS.
KW  - QPSK link.
KW  - RLS algorithm.
KW  - SNR.
KW  - Adaptive frequency-domain equalization.
KW  - Adaptive processing.
KW  - Average bit error rate.
KW  - Broadband wireless communications.
KW  - Cellular telephony.
KW  - Channel tracking.
KW  - Convergence.
KW  - Delay spread.
KW  - Digital signal processing technology.
KW  - Diversity combining.
KW  - Equalizer performance.
KW  - Frequency-selective Rayleigh fading multipath channel.
KW  - Least mean square.
KW  - Mobile speeds.
KW  - Optimum linear receiver performance.
KW  - Quaternary phase-shift keying.
KW  - Recursive least squares.
KW  - Signal-to-noise ratio.
KW  - Spatial-frequency domain.
KW  - Time-domain equalizer.
ER  -