1,026 research outputs found
Filter Bank Multicarrier for Massive MIMO
This paper introduces filter bank multicarrier (FBMC) as a potential
candidate in the application of massive MIMO communication. It also points out
the advantages of FBMC over OFDM (orthogonal frequency division multiplexing)
in the application of massive MIMO. The absence of cyclic prefix in FBMC
increases the bandwidth efficiency. In addition, FBMC allows carrier
aggregation straightforwardly. Self-equalization, a property of FBMC in massive
MIMO that is introduced in this paper, has the impact of reducing (i)
complexity; (ii) sensitivity to carrier frequency offset (CFO); (iii)
peak-to-average power ratio (PAPR); (iv) system latency; and (v) increasing
bandwidth efficiency. The numerical results that corroborate these claims are
presented.Comment: 7 pages, 6 figure
Frequency Spreading Equalization in Multicarrier Massive MIMO
Application of filter bank multicarrier (FBMC) as an effective method for
signaling over massive MIMO channels has been recently proposed. This paper
further expands the application of FBMC to massive MIMO by applying frequency
spreading equalization (FSE) to these channels. FSE allows us to achieve a more
accurate equalization. Hence, higher number of bits per symbol can be
transmitted and the bandwidth of each subcarrier can be widened. Widening the
bandwidth of each subcarrier leads to (i) higher bandwidth efficiency; (ii)
lower complexity; (iii) lower sensitivity to carrier frequency offset (CFO);
(iv) reduced peak-to-average power ratio (PAPR); and (iv) reduced latency. All
these appealing advantages have a direct impact on the digital as well as
analog circuitry that is needed for the system implementation. In this paper,
we develop the mathematical formulation of the minimum mean square error (MMSE)
FSE for massive MIMO systems. This analysis guides us to decide on the number
of subcarriers that will be sufficient for practical channel models.Comment: Accepted in IEEE ICC 2015 - Workshop on 5G & Beyond - Enabling
Technologies and Application
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
Adaptive antennas at the mobile and base stations in an OFDM/TDMA system
In recent years, several smart antenna systems have been proposed and demonstrated at the base station (BS) of wire-less communications systems, and these have shown that significant system performance improvement is possible. In this paper, we consider the use of adaptive antennas at the BS and mobile stations (MS), operating jointly, in combination with orthogonal frequency-division multiplexing. The advantages of the proposed system includes reductions in average error probability and increases in capacity compared to conventional systems. Multiuser access, in space, time, and through subcarriers, is also possible and expressions for the exact joint optimal antenna weights at the BS and MS under cochannel interference conditions for fading channels are derived. To demonstrate the potential of our proposed system, analytical along with Monte Carlo simulation results are provided
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