1,506 research outputs found
A Comparison of CP-OFDM, PCC-OFDM and UFMC for 5G Uplink Communications
Polynomial-cancellation-coded orthogonal frequency division multiplexing
(PCC-OFDM) is a form of OFDM that has waveforms which are very well localized
in both the time and frequency domains and so it is ideally suited for use in
the 5G network. This paper analyzes the performance of PCC-OFDM in the uplink
of a multiuser system using orthogonal frequency division multiple access
(OFDMA) and compares it with conventional cyclic prefix OFDM (CP-OFDM), and
universal filtered multicarrier (UFMC). PCC-OFDM is shown to be much less
sensitive than either CP-OFDM or UFMC to time and frequency offsets. For a
given constellation size, PCC-OFDM in additive white Gaussian noise (AWGN)
requires 3dB lower signal-to-noise ratio (SNR) for a given bit-error-rate, and
the SNR advantage of PCC-OFDM increases rapidly when there are timing and/or
frequency offsets. For PCC-OFDM no frequency guard band is required between
different OFDMA users. PCC-OFDM is completely compatible with CP-OFDM and adds
negligible complexity and latency, as it uses a simple mapping of data onto
pairs of subcarriers at the transmitter, and a simple weighting-and-adding of
pairs of subcarriers at the receiver. The weighting and adding step, which has
been omitted in some of the literature, is shown to contribute substantially to
the SNR advantage of PCC-OFDM. A disadvantage of PCC-OFDM (without overlapping)
is the potential reduction in spectral efficiency because subcarriers are
modulated in pairs, but this reduction is more than regained because no guard
band or cyclic prefix is required and because, for a given channel, larger
constellations can be used
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
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