Intrinsic interference mitigating coordinated beamforming for the FBMC/OQAM based downlink (original) (raw)
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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],
This paper provides solutions for per-user multistream transmissions in FBMC/OQAM based multi-user MIMO downlink systems under highly frequency selective propagation conditions. A signal-to-leakage-plus-noise-ratio (SLNR) based metric is proposed, and it is tailored for the downlink of FBMC/OQAM based multi-user MIMO settings. Then at the base station, per-subcarrier fractionally spaced multi-tap precoders are computed based on this metric to mitigate the multi-user interference (MUI), the inter-symbol interference (ISI), as well as the inter-carrier interference (ICI) and to map the multiple data streams of each user to the transmit antennas. With the base station carrying most of the computational load, each user terminal only employs a zero-forcing (ZF) based one-tap spatial equalizer to recover the desired streams. Simulation results show that the proposed SLNR based precoding scheme achieves satisfactory performances in various multi-user MIMO downlink scenarios. It significantly outperforms the existing algorithms that require the channel on each subcarrier to be flat fading.
Receiver Processing and Limited-Feedback User Scheduling for Multiuser MIMO and MIMO-OFDM Downlink
2009
Multiple-input multiple-output orthogonal frequency division multiplexing (MIMO-OFDM) has been proposed for many emerging standards and seems to be a promising solution for future high data rate wireless communications. In the first part of this thesis, a novel sub-optimum detection method called unified successive interference cancellation (U-SIC) for spatially multiplexed multicarrier code division multiplexing (SM-MC-CDM) transmission is proposed. It is shown that compared I would like to express my profound appreciation and sincere gratitude to my advisor, Dr. Witold A. Krzymień, for his guidance, patience and support throughout this work. I am very grateful for his insights and advice. I would also like to thank Dr. Xiaodai Dong for her support and guidance during the first two years of my Ph.D. program.
A Study on Recent Advancements in MIMO-FBMC Systems
International Journal of Computer Applications, 2014
Multicarrier (MC) techniques when combined with Multiple Input Multiple Output (MIMO) technology increases the throughput and QOS of the system. OFDM with its unique capability of converting the frequency selective channel into a set of frequency flat channel have proved to be one of the best multicarrier technique that can be applied to MIMO channels. However, OFDM suffers from Bandwidth loss due to the addition of cyclic prefix. Filter bank multicarrier (FBMC) modulation system on the other hand, is highly bandwidth efficient but its application to MIMO channels is still a subject of study to various researchers for the past decade. So far, only FMT based FBMC system offers same flexibility as OFDM in adopting MIMO techniques. This paper presents the various advancements or methods proposed to enhance the flexibility of FBMC systems (FMT,CMT,OFDM-OQAM) while adopting MIMO techniques mainly highlighting the ISI and ICI mitigation methods through improved decoding techniques, equalization schemes and modified FBMC schemes.
OFDM and FBMC performance comparison for multistream MIMO systems
Future Network and Mobile …
A comparison between two multicarrier (MC) transmission techniques is presented: OFDM, based on cyclic prefix (CP), and FBMC, based on filterbank architecture. Multistream multiple input multiple output (MIMO) techniques that require channel state information (CSI) at the transmitter and receiver, are applied in these schemes to improve their throughput. When perfect CSI is assumed, OFDM presents lower energy-efficiency than FBMC due to the use of the CP. However, unlike OFDM, the use of multiple streams increases interference in FBMC. When imperfect CSI is considered, while there is neither inter-symbol interference (ISI) nor inter-carrier interference (ICI) in OFDM, FBMC still suffers this effect. In scenarios with low coherence bandwidth channels, the performance of FBMC degrades due to a significant increase in interference. On the contrary, OFDM is shown to be more robust in such scenarios. In this paper, we explore analytically and by means of simulation, the sources of errors together with the effects of channel coherence bandwidth and the energy-efficiency trade-off observed for both systems.
Performance comparison between FBMC and OFDM in MIMO systems under channel uncertainty
2010 European Wireless Conference (EW), 2010
In this paper we present a comparison between two different multi-carrier transmission techniques: OFDM, based on the FFT and cyclic prefix (CP) addition; and OFDM/OQAM, based on a filterbank architecture. For both schemes, we propose a simple joint beamforming design to be applied in multi-inputmulti-output (MIMO) systems, which requires channel state information (CSI) at both communication ends.
Multi-User Interference Cancellation for Uplink FBMC-Based Multiple Access Channel
IEEE Communications Letters, 2021
In the uplink of multi-user systems, signals from different users may arrive at the base station with different timing offsets (TO), which degrades the performance of conventional OFDM systems. In this letter, an FBMC-based multiple access channel with timing errors is considered under frequency selective channels. To eliminate the intrinsic interference (InI), TO-induced interference (TOI) and multi-user interference (MUI) terms, an iterative receiver is proposed. The proposed receiver combines bit-interleaved coded modulation with iterative decoding (BICM-ID) processing with parallel interference cancellation and iterative interference cancellation. The results show that FBMC is robust to timing errors and the proposed receiver can effectively eliminate the interference terms. This motivates the use of FBMC as an alternative to OFDM in applications that require asynchronous transmissions.
Performance of Multiuser MIMO-OFDM downlink system with ZF-BF and MMSE-BF linear precoding
International Journal of Innovation and Applied Studies, 2013
The forthcoming wireless communication networks, commonly referred to as fourth generation (4G) systems, are expected to support extremely high data rates as close as possible to the theoretical channel capacity while satisfying quality of service (QoS) constraints. The development of these systems must take into account the problem of limited radio resources and the harshness of wireless channel conditions. Two emerging technologies that are potential candidates for 4G wireless networks are multiuser multiple-input multiple-output (MU-MIMO) wireless systems and orthogonal frequency division multiplexing (OFDM). The MU-MIMO technique allows the spatial multiplexing gain at the base station to be obtained without the need for multiple antenna terminals, thereby allowing multiple users to receive data over the downlink simultaneously. The use of OFDM provides protection against intersymbol interference (ISI) and allows high data rates to be achieved. Linear precoding schemes for MU-MIMO wireless systems, e.g., zero forcing beamforming (ZF-BF) and minimum mean squared error beamforming (MMSE-BF), have been widely concerned for their high performance in single-carrier MU-MIMO networks where a base station attempts to communicate simultaneously with multiple users. In this paper, we evaluate and extend the ZF-BF and MMSE-BF schemes from single-carrier MU-MIMO to multicarrier MU-MIMO architecture based on OFDM, i.e., MU-MIMO-OFDM system, assuming the availability of channel state information (CSI) at the transmitter. Numerical results demonstrate that both introduced linear precoding strategies provide a higher sum-rate capacity improvement compared to a conventional MU-MIMO-OFDM system where the users are served on a time division multiple access (TDMA) basis.
EQSM-based multiuser MIMO downlink transmission for correlated fading channels
EURASIP Journal on Wireless Communications and Networking
This paper presents three multiuser multiple input-multiple output (MU-MIMO) downlink transmission strategies based on the extended quadrature spatial modulation (EQSM) system for mobile communication. The three MU-MIMO precoding strategies utilised are block diagonalisation (BD), dirty paper coding (DPC), and a combined BD-DPC strategy. We analyse and compare the performance of these three MU-MIMO-EQSM schemes with the conventional MU-MIMO spatial multiplexing (MU-MIMO-SMux) system in terms of bit error rate (BER) and detection complexity considering correlated and uncorrelated fading channels. Results show that the BD-MIMO-EQSM and DPC-MIMO-EQSM systems outperform by 2−3 dB in BER performance their conventional counterparts with the additional advantage of a detection complexity reduction of up to 62% for the analysed cases. For the uncorrelated fading channel, the BD technique has better BER performance for a spectral efficiency (SE) of 12 bits per channel use (bpcu), while the D...
Joint Space-Frequency Iterative Interference Suppression in Multiuser MIMO-OFDM Systems
IEEE Communications Letters, 2007
In uplink multiuser multiple-input multiple-output (MIMO) orthogonal frequency-division multiplexing (OFDM) systems, inter-user interference includes co-channel interference (CCI) due to spatial multiplexing and inter-carrier interference (ICI) due to carrier-frequency offset (CFO). In this letter, a space-frequency joint processing scheme is proposed to suppress the two-dimensional interference alternatively and iteratively. Moreover, by the studies of convergence behavior of iterations, a sufficient condition for convergence is presented. The theoretical analysis and simulation results both show that this iterative scheme can effectively suppress inter-user interference with low complexity.