In this letter, we propose two computationally efficient precoding algorithms that achieve near-ML performance for multiuser MIMO downlink. The proposed algorithms perform tree expansion after lattice reduction. The first full expansion is tried by selecting the first level node with a minimum metric, constituting a reference metric. To find an optimal sequence, they iteratively visit each node...

An iterative receiver for Multiple-Input Multiple-Output (MIMO) Orthogonal Frequency Division Multiplexing (OFDM) systems in time-frequency wireless channels is presented. Multi-User Detection (MUD) and Channel Estimation (CE) are performed using soft information iteratively provided by the single-user decoders. Bidimensional Slepian expansion exploits time and frequency channel variation. Perf...

In this paper we investigate the deployment of filtered multitone (FMT) modulation over in-home wireless channels. We propose the adaptation of parameters (overhead factor) to the channel condition. Optimal and sub-optimal approaches are described. Comparisons with orthogonal frequency division multiplexing (OFDM) show that FMT provides significant improvements both in single user and multi use...

Multi-User Orthogonal Frequency Division Multiplexing (MU-OFDM) is an efficient technique for achieving high downlink capacity in high-speed communication systems. A key issue in MU-OFDM is the allocation of the OFDM subcarriers and power to users sharing the channel. In this paper a proportional rate-adaptive resource allocation algorithm for MU-OFDM is presented. Subcarrier and power allocati...

Orthogonal frequency division multiplexing (OFDM) is a multi-carrier digital modulation technique. It’s likely to be used in next generation high-speed railway communication system. When OFDM is used in the communication of high-speed railway user s, Doppler frequency shift will become an important technical barrier, because OFDM is sensitive to frequency offset. Especially in high-speed moveme...

In this thesis, a number of semi-blind structures are proposed for Orthogonal Frequency Division Multiplexing (OFDM) based wireless communication systems, with Carrier Frequency Offset (CFO) estimation and Independent Component Analysis (ICA) based equalization. In the first contribution, a semi-blind non-redundant single-user Multiple-Input Multiple-Output (MIMO) OFDM system is proposed, with ...

Space Division Multiple Access (SDMA) aided Oralso been employed in OFDM systems [7, 8] for achieving a nearthogonal Frequency Division Multiplexing (OFDM) systems assisted optimum performance. Against this background, the novel contriby efficient Multi-User Detection (MUD) techniques have recently bution of this paper is that we propose a MMSE-assisted Iteraattracted intensive research interes...

This work presents joint subcarrier, power and bit allocation schemes for multi-user OFDM based overlay cognitive radio under constraints on primary user throughput loss and total secondary user transmitted power. Closed form for expressions for the optimal power and bit allocations are initially derived. Subsequently, optimal and suboptimal algorithms to realise the joint subcarrier, power and...

Abstract This paper describes the experimental investigation of orthogonal time-frequency space (OTFS) modulation using a 28 GHz multi-user distributed multiple-input multiple-output (D-MIMO) testbed in over-the-air (OTA) and mobility environments to enhance cell throughput millimeter-wave band. We build D-MIMO having newly developed OTFS modulator demodulator, measured signals frequency-divisi...