Trellis-Based Receivers for SC-FDMA Transmission over MIMO ISI Channels

Abstract

Abstract-For the uplink of the E-UTRA Long Term Evolution (LTE) system, single-carrier frequency-division multiple access (SC-FDMA) transmission has been selected. Frequency-domain linear and decision-feedback equalizers have been already given in the literature for an SC-FDMA transmission over a multipleinput multiple-output (MIMO) intersymbol interference (ISI) channel. In this paper, a soft-output trellis-based equalizer is proposed, taking into account the cyclic ISI structure arising in SC-FDMA, which is especially suited for turbo-encoded transmission over channels with low-to-moderate signal-to-noise ratios (SNRs). A preprocessing stage is necessary for the trellisbased equalizer consisting of a minimum mean-squared error (MMSE) MIMO linear equalizer and a MIMO prediction-error filter, whose design is addressed. Simulation results for an LTE scenario demonstrate that the novel receiver yields significant gains compared to MMSE linear equalization in particular for square MIMO systems.

Performance limits of conventional and widely linear DFT-precoded-OFDM receivers in wideband frequency-selective channels

“…The solution obtained in our case becomes a multiple-receiver antenna generalization of the results presented in [21]. Similarly, Gerstacker et al [31] presented an alternative approach for MIMO systems where the problem of designing the FBF is formulated as one of finite length prediction error filter design. This alternative approach results in a solution that agrees with our results for the multiple-receiver antenna case.…”

“…The results of this paper show that MMSE-LE-based initialization is sufficient to obtain near-ideal performance. An alternative receiver initialization method is also discussed in [31] for trellis-based receivers. Different iterative block DFE methods have been proposed in [23,32] for DFEprecoded-OFDMA systems.…”

“…MMSE-DFE filter expressions are given in [21] for the single-receiver antenna case and results for multipleinput-multiple-output (MIMO) systems are available in [31]. In order to obtain an expression for the mean-square error (MSE) which enables closed-form analysis in i.i.d.…”

“…In DFT-precoded-OFDM systems, the MMSE-DFE [18][19][20] equalizer can be implemented efficiently using a frequency domain FFF followed by a time domain DFE [21][22][23][24][25][26][27][28][29][30][31]. Computation of FFF and feedback filters (FBF) for DFT-precoded-OFDM differs from conventional singlecarrier methods.…”

A Novel User Pairing Algorithm for Lte Femtocell Uplink

“…donates the size of the modulation alphabet; donates Q function, which is defined as where M is the number of subcarriers; the intermedium variable Σ 1 is constrained by the following equation [11]:…”