686 research outputs found
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
Time-Frequency Warped Waveforms
The forthcoming communication systems are advancing towards improved
flexibility in various aspects. Improved flexibility is crucial to cater
diverse service requirements. This letter proposes a novel waveform design
scheme that exploits axis warping to enable peaceful coexistence of different
pulse shapes. A warping transform manipulates the lattice samples non-uniformly
and provides flexibility to handle the time-frequency occupancy of a signal.
The proposed approach enables the utilization of flexible pulse shapes in a
quasi-orthogonal manner and increases the spectral efficiency. In addition, the
rectangular resource block structure, which assists an efficient resource
allocation, is preserved with the warped waveform design as well.Comment: 4 pages, 5 figures; accepted version (The URL for the final version:
http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=8540914&isnumber=8605392
Multi-service systems: an enabler of flexible 5G air-interface
Multi-service system is an enabler to flexibly support
diverse communication requirements for the next generation
wireless communications. In such a system, multiple types of
services co-exist in one baseband system with each service having
its optimal frame structure and low out of band emission (OoBE)
waveforms operating on the service frequency band to reduce the
inter-service-band-interference (ISvcBI). In this article, a
framework for multi-service system is established and the
challenges and possible solutions are studied. The multi-service
system implementation in both time and frequency domain is
discussed. Two representative subband filtered multicarrier
(SFMC) waveforms: filtered orthogonal frequency division
multiplexing (F-OFDM) and universal filtered multi-carrier
(UFMC) are considered in this article. Specifically, the design
methodology, criteria, orthogonality conditions and prospective
application scenarios in the context of 5G are discussed. We
consider both single-rate (SR) and multi-rate (MR) signal
processing methods. Compared with the SR system, the MR
system has significantly reduced computational complexity at the
expense of performance loss due to inter-subband-interference
(ISubBI) in MR systems. The ISvcBI and ISubBI in MR systems
are investigated with proposed low-complexity interference
cancelation algorithms to enable the multi-service operation in
low interference level conditions
Efficient Fast-Convolution-Based Waveform Processing for 5G Physical Layer
This paper investigates the application of fast-convolution (FC) filtering
schemes for flexible and effective waveform generation and processing in the
fifth generation (5G) systems. FC-based filtering is presented as a generic
multimode waveform processing engine while, following the progress of 5G new
radio standardization in the Third-Generation Partnership Project, the main
focus is on efficient generation and processing of subband-filtered cyclic
prefix orthogonal frequency-division multiplexing (CP-OFDM) signals. First, a
matrix model for analyzing FC filter processing responses is presented and used
for designing optimized multiplexing of filtered groups of CP-OFDM physical
resource blocks (PRBs) in a spectrally well-localized manner, i.e., with narrow
guardbands. Subband filtering is able to suppress interference leakage between
adjacent subbands, thus supporting independent waveform parametrization and
different numerologies for different groups of PRBs, as well as asynchronous
multiuser operation in uplink. These are central ingredients in the 5G waveform
developments, particularly at sub-6-GHz bands. The FC filter optimization
criterion is passband error vector magnitude minimization subject to a given
subband band-limitation constraint. Optimized designs with different guardband
widths, PRB group sizes, and essential design parameters are compared in terms
of interference levels and implementation complexity. Finally, extensive coded
5G radio link simulation results are presented to compare the proposed approach
with other subband-filtered CP-OFDM schemes and time-domain windowing methods,
considering cases with different numerologies or asynchronous transmissions in
adjacent subbands. Also the feasibility of using independent transmitter and
receiver processing for CP-OFDM spectrum control is demonstrated
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