Abstract
There has been greatly increasing interest in orthogonal frequency division multiplexing (OFDM) for broadband wireless transmission due to its robustness against multipath fading. However, OFDM signals have high peak-to-average power ratio (PAPR), and thus, a power amplifier must be operated with a large input power backoff (IBO). Recently, OFDM combined with time division multiplexing (OFDM/TDM) using minimum mean square error-frequency domain equalization (MMSE-FDE) has been presented to reduce the PAPR, while improving the bit error rate (BER) performance of conventional OFDM. In this article, by extensive computer simulation, we present a comprehensive performance comparison of OFDM-based schemes in a nonlinear and frequency-selective fading channel. We discuss about the transmission performance of OFDM-based schemes with respect to the transmit peak-power, the achievable capacity, the BER performance, and the signal bandwidth. Our results show that OFDM/TDM using MMSE-FDE achieves a lower peak-power and capacity than conventional OFDM, which means significant reduction of amplifier transmit-power backoff, but with a slight decrease in signal bandwidth occupancy.
Highlights
In a wireless channel, a signal propagates over a number of different paths that give rise to a frequency-selective fading, which produce severe inter-symbol interference (ISI) and degrades the transmission performance [1]
orthogonal frequency division multiplexing (OFDM) combined with time division multiplexing (OFDM/TDM) [15] using minimum mean square error frequency domain channel equalization (FDE) (MMSE-FDE) [16] was presented to reduce the peak-toaverage power ratio (PAPR), while improving the bit error rate (BER) performance of conventional OFDM
Our aim is to show that OFDM/TDM using MMSE-FDE can be used in practical systems to overcome the high PAPR problem of conventional OFDM at the cost of slight decrease in spectrum efficiency
Summary
A signal propagates over a number of different paths that give rise to a frequency-selective fading, which produce severe inter-symbol interference (ISI) and degrades the transmission performance [1]. To solve this problem, intensive research effort on frequency domain channel equalization (FDE) is currently ongoing in two directions: (i) orthogonal frequency division multiplexing (OFDM) [2], and (ii) single carrier (SC)-FDE [3]. In [14], the performance of clipped OFDM is analyzed in terms of the PAPR reduction capability and degradation of the channel capacity.
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