1,825 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
Efficient implementation of filter bank multicarrier systems using circular fast convolution
In this paper, filter bank-based multicarrier systems using a fast convolution approach are investigated. We show that exploiting offset quadrature amplitude modulation enables us to perform FFT/IFFT-based convolution without overlapped processing, and the circular distortion can be discarded as a part of orthogonal interference terms. This property has two advantages. First, it leads to spectral efficiency enhancement in the system by removing the prototype filter transients. Second, the complexity of the system is significantly reduced as the result of using efficient FFT algorithms for convolution. The new scheme is compared with the conventional waveforms in terms of out-of-band radiation, orthogonality, spectral efficiency, and complexity. The performance of the receiver and the equalization methods are investigated and compared with other waveforms through simulations. Moreover, based on the time variant nature of the filter response of the proposed scheme, a pilot-based channel estimation technique with controlled transmit power is developed and analyzed through lower-bound derivations. The proposed transceiver is shown to be a competitive solution for future wireless networks
On Max-SINR Receiver for Hexagonal Multicarrier Transmission Over Doubly Dispersive Channel
In this paper, a novel receiver for Hexagonal Multicarrier Transmission (HMT)
system based on the maximizing Signal-to-Interference-plus-Noise Ratio
(Max-SINR) criterion is proposed. Theoretical analysis shows that the prototype
pulse of the proposed Max-SINR receiver should adapt to the root mean square
(RMS) delay spread of the doubly dispersive (DD) channel with exponential power
delay profile and U-shape Doppler spectrum. Simulation results show that the
proposed Max-SINR receiver outperforms traditional projection scheme and
obtains an approximation to the theoretical upper bound SINR performance within
the full range of channel spread factor. Meanwhile, the SINR performance of the
proposed prototype pulse is robust to the estimation error between the
estimated value and the real value of time delay spread.Comment: 6 pages. The paper has been published in Proc. IEEE GLOBECOM 2012.
Copyright transferred to IEEE. arXiv admin note: text overlap with
arXiv:1212.579
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
Modeling Interference Between OFDM/OQAM and CP-OFDM: Limitations of the PSD-Based Model
To answer the challenges put out by the next generation of wireless networks
(5G), important research efforts have been undertaken during the last few years
to find new waveforms that are better spectrally localized and less sensitive
to asynchronism effects than the widely deployed Cyclic Prefix Orthogonal
Frequency Division Multiplexing (CP-OFDM). One of the most studied schemes is
OFDM-Offset Quadrature Amplitude Modulation (OFDM/OQAM) based on the PHYDYAS
filter pulse. In the recent literature, spectrum coexistence between OFDM/OQAM
and CP-OFDM is commonly studied based on the Power Spectral Density (PSD)
model. In this paper, we show that this approach is flawed and we show that the
actual interference injected by OFDM/OQAM systems onto CP-OFDM is much higher
than what is classically expected with the PSD based model in the literature.
We show that though using OFDM/OQAM in secondary systems is still advantageous,
it brings limited gain in the context of coexistence with incumbent CP-OFDM
systems.Comment: 7 pages, 9 figures, ICT 201
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