Linear receivers for massive MIMO FBMC/OQAM under strong channel frequency selectivity (original) (raw)

Filter Bank Multicarrier for Massive MIMO

2014 IEEE 80th Vehicular Technology Conference (VTC2014-Fall), 2014

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.

Filter Bank Multicarrier in Massive MIMO: Analysis and Channel Equalization

IEEE Transactions on Signal Processing, 2018

We perform an asymptotic study of the performance of filter bank multicarrier (FBMC) in the context of massive multi-input multi-output (MIMO). We show that the effects of channel distortions, i.e., intersymbol interference and intercarrier interference, do not vanish as the base station (BS) array size increases. As a result, the signal-to-interference-plus-noise ratio (SINR) cannot grow unboundedly by increasing the number of BS antennas, and is upper bounded by a certain deterministic value. We show that this phenomenon is a result of the correlation between the multi-antenna combining tap values and the channel impulse responses between the mobile terminals and the BS antennas. To resolve this problem, we introduce an efficient equalization method that removes this correlation, enabling us to achieve arbitrarily large SINR values by increasing the number of BS antennas. We perform a thorough analysis of the proposed system and find analytical expressions for both equalizer coefficients and the respective SINR.

Spectral Efficiency of Massive MIMO using FBMC-OQAM Modulation

Anais de XXXVI Simpósio Brasileiro de Telecomunicações e Processamento de Sinais

This article covers the potential of Filter Bank Multicarrier (FBMC) modulation to be used in the future 5G wireless networks where Massive Multiple-Input Multiple-Output (MIMO) will be deployed. The study compares orthogonal frequency division multiplexing (OFDM) with FBMC. The former is the multiplexing technique in 4G communications and the latter is one of the strongest candidates to replace OFDM in 5G networks. This comparison evaluates the spectral efficiency (SE) of a massive MIMO (MM) system uplink under a singlecell environment. Due to the absence of the cyclic prefix, the FBMC has better SE than the OFDM as the signal-to-noise-ratio (SNR) increases. However, to the best of the authors' knowledge, this study has not yet been conducted under a MM scenario. In summary, this article presents an analysis of SE of FBMC considering a MM setup. While limiting the modulation to 64-Quadrature Amplitude Modulation (QAM) per sub carrier, it was observed that as the SE increases, the required number of antennas for the OFDM becomes the double or the triple of the counterpart using FBMC, or even it is not achieved by the OFDM.

Spectral Efficiency Analysis in Massive MIMO using FBMC-OQAM Modulation

Journal of Microwaves, Optoelectronics and Electromagnetic Applications

This article covers the potential of Filter Bank Multicarrier (FBMC) modulation as an alternative to be used in the future 5G wireless networks in which Massive Multiple-Input Multiple-Output (MIMO) will be deployed. The study compares orthogonal frequency division multiplexing (OFDM) with FBMC. The former is the multiplexing technique in 4G communications and the latter is one of the strongest candidates to replace OFDM in 5G networks. This comparison evaluates the spectral efficiency (SE) of a Massive MIMO (MM) system uplink under a single-cell environment. The diversity in MM permits a self-equalization of the channel, which the FBMC further benefits from, due to the confinement of the subcarrier in an assigned range. Due to the absence of the cyclic prefix, the FBMC has better SE than the OFDM for increasing signal-to-noise-ratio (SNR). One may find a scarce literature covering the FBMC in a large-scale multiuser MIMO scenario, which considers a large number of antennas at the base station (BS). Various scenarios are considered by varying the number of antennas, users and different cell radius. Moreover, the subcarrier modulations are simulated, and not considered Gaussian distributed, as in Shannon limit theory. In some cases, the FBMC allows doubling the cell radius for the same SE value of 3.8 bits/s/Hz/user. For a fixed cell radius of 750m and a SE of 3.5 bits/s/Hz/user, the OFDM requires three times more antennas than FBMC when both modulations are under the same conditions.

Frequency spreading equalization in multicarrier massive MIMO

2015 IEEE International Conference on Communication Workshop (ICCW), 2015

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.

Channel Equalization for Multi-Antenna FBMC/OQAM Receivers

IEEE Transactions on Vehicular Technology, 2000

In this paper, the problem of channel equalization in filter bank multicarrier (FBMC) transmission based on the offset QAM (OQAM) subcarrier modulation is addressed. Finite impulse response (FIR) per-subchannel equalizers are derived, based on the frequency sampling (FS) approach, both for the single-input multiple-output (SIMO) receive diversity and the multiple-input multiple-output (MIMO) spatially-multiplexed FBMC/OQAM systems. The FS design consists of computing the equalizer in the frequency domain at a number of frequency points within a subchannel bandwidth, based on which the coefficients of subcarrier-wise equalizers are derived. We evaluate the error rate performance and computational complexity of the proposed scheme for the both antenna configurations and compare them with those of the SIMO/MIMO OFDM equalizers. The obtained results confirm the effectiveness of the proposed technique with channels that exhibit significant frequency selectivity at subchannel level, and show a performance comparable to that of the optimum minimum mean squared error (MMSE) equalizer despite a significantly lower computational complexity. The possibility of tolerating a significant subchannel frequency selectivity gives more freedom in the multicarrier system parametrization. For example, it is possible to use a significantly wider subcarrier spacing than what is feasible in OFDM, thus relieving various critical design constraints.

Prototype filter design for FBMC in massive MIMO channels

2017 IEEE International Conference on Communications (ICC), 2017

We perform an asymptotic study on the performance of filter bank multicarrier (FBMC) in the context of massive multi-input multi-output (MIMO). We show that the signal-tointerference-plus-noise ratio (SINR) cannot grow unboundedly by increasing the number of base station (BS) antennas, and is upper bounded by a certain deterministic value. This is a result of the correlation between the multi-antenna combining tap values and the channel impulse responses between the terminals and the BS antennas. To solve this problem, we introduce a simple FBMC prototype filter design method that removes this correlation, enabling us to achieve arbitrarily large SINR values by increasing the number of BS antennas.

Towards a non-error floor multi-stream beamforming design for FBMC/OQAM

2015 IEEE International Conference on Communications (ICC), 2015

This paper investigates the application of filter bank multicarrier modulation based on the OQAM (FBMC/OQAM) to multiple-input-multiple-output (MIMO) systems. Existing solutions guarantee satisfactory performance when the streams multiplexed on each subcarrier (S) and the number of transmit (NT) and receive (NR) antennas are related as S = min (NT , NR). When S < min (NT , NR), the techniques presented in previous works either exhibit an error floor or perform much worse than orthogonal frequency division multiplexing (OFDM). To make progress towards the combination of FBMC/OQAM with MIMO we propose a two-step approach and a coordinated beamforming algorithm to design the transmit and the receive processing. Numerical results show that the two-step method provides similar bit error rate (BER) as OFDM when S + 1 = NT = NR. Resorting to the coordinated beamforming solution, which is based on an iterative method, the application of FBMC/OQAM is extended to the general case S < min (NT , NR). Hence, the techniques presented in this paper demonstrate that FBMC/OQAM can achieve practically the same BER as OFDM with an increased spectral efficiency and a significantly decreased out-of-band radiation, which is an important advantage for non-contiguous spectrum allocations. • Simulation-based results show that the two-step approach remains competitive with OFDM and outperforms [4],

FBMC Receiver Design and Analysis for Medium and Large Scale Antenna Systems

IEEE Transactions on Vehicular Technology, 2022

In this paper, we design receivers for filter bank multicarrier-based (FBMC-based) massive MIMO considering practical aspects such as channel estimation and equalization. In particular, we propose a spectrally efficient pilot structure and a channel estimation technique in the uplink to jointly estimate all the users' channel impulse responses. We mathematically analyze our proposed channel estimator and find the statistics of the channel estimation errors. These statistics are incorporated into our proposed equalizers to deal with the imperfect channel state information (CSI) effect. We revisit the channel equalization problem for FBMC-based massive MIMO, address the shortcomings of the existing equalizers in the literature, and make them more applicable to practical scenarios. The proposed receiver in this paper consists of two stages. In the first stage, a linear combining of the received signals at the base station (BS) antennas provides a coarse channel equalization and removes any multiuser interference. In the second stage, a per subcarrier fractionally spaced equalizer (FSE) takes care of any residual distortion of the channel for the user of interest. We propose an FSE design based on the equivalent channel at the linear combiner output. This enables the applicability of our proposed technique to small and/or distributed antenna setups such as cell-free massive MIMO. Finally, the efficacy of the proposed techniques is corroborated through numerical analysis.