112 research outputs found
Dual-Polarization OFDM-OQAM Wireless Communication System
In this paper we describe the overall idea and results of a recently proposed
radio access technique based on filter bank multicarrier (FBMC) communication
system using two orthogonal polarizations: dual-polarization FBMC (DP-FBMC).
Using this system we can alleviate the intrinsic interference problem in FBMC
systems. This enables use of all the multicarrier techniques used in
cyclic-prefix orthogonal frequency-division multiplexing (CP-OFDM) systems for
channel equalization, multiple-input/multiple-output (MIMO) processing, etc.,
without using the extra processing required for conventional FBMC. DP-FBMC also
provides other interesting advantages over CP-OFDM and FBMC such as more
robustness in multipath fading channels, and more robustness to receiver
carrier frequency offset (CFO) and timing offset (TO). For DP-FBMC we propose
three different structures based on different multiplexing techniques in time,
frequency, and polarization. We will show that one of these structures has
exactly the same system complexity and equipment as conventional FBMC. In our
simulation results DP-FBMC has better bit error ratio (BER) performance in
dispersive channels. Based on these results, DP-FBMC has potential as a
promising candidate for future wireless communication systems.Comment: 1.This paper is accepted to be published in IEEE Vehicular Technology
Conference (VTC) FALL 2018. 2.In this new submitted version authors have
revised the paper based on the VTC FALL reviewers comments. Therefore some
typos have fixed and some results have change
Waveform Design for 5G and Beyond
5G is envisioned to improve major key performance indicators (KPIs), such as
peak data rate, spectral efficiency, power consumption, complexity, connection
density, latency, and mobility. This chapter aims to provide a complete picture
of the ongoing 5G waveform discussions and overviews the major candidates. It
provides a brief description of the waveform and reveals the 5G use cases and
waveform design requirements. The chapter presents the main features of cyclic
prefix-orthogonal frequency-division multiplexing (CP-OFDM) that is deployed in
4G LTE systems. CP-OFDM is the baseline of the 5G waveform discussions since
the performance of a new waveform is usually compared with it. The chapter
examines the essential characteristics of the major waveform candidates along
with the related advantages and disadvantages. It summarizes and compares the
key features of different waveforms.Comment: 22 pages, 21 figures, 2 tables; accepted version (The URL for the
final version:
https://onlinelibrary.wiley.com/doi/abs/10.1002/9781119333142.ch2
Single- versus Multi-Carrier Terahertz-Band Communications: A Comparative Study
The prospects of utilizing single-carrier (SC) and multi-carrier (MC)
waveforms in future terahertz (THz)-band communication systems remain
unresolved. On the one hand, the limited multi-path components at high
frequencies result in frequency-flat channels that favor low-complexity
wideband SC systems. On the other hand, frequency-dependent molecular
absorption and transceiver characteristics and the existence of multi-path
components in indoor sub-THz systems can still result in frequency-selective
channels, favoring off-the-shelf MC schemes such as orthogonal
frequency-division multiplexing (OFDM). Variations of SC/MC designs result in
different THz spectrum utilization, but spectral efficiency is not the primary
concern with substantial available bandwidths; baseband complexity, power
efficiency, and hardware impairment constraints are predominant. This paper
presents a comprehensive study of SC/MC modulations for THz communications,
utilizing an accurate wideband THz channel model and highlighting the various
performance and complexity trade-offs of the candidate schemes. Simulations
demonstrate that discrete-Fourier-transform spread orthogonal time-frequency
space (DFT-s-OTFS) achieves a lower peak-to-average power ratio (PAPR) than
OFDM and OTFS and enhances immunity to THz impairments and Doppler spreads, but
at an increased complexity cost. Moreover, DFT-s-OFDM is a promising candidate
that increases robustness to THz impairments and phase noise (PHN) at a low
PAPR and overall complexity.Comment: 18 pages, 12 figures, journa
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