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In this paper, we propose a novel transmit signal structure for OFDM (orthogonal frequency division multiplexing). Instead of the conventional cyclic prefix (CP), we use a deterministic sequence, which we call unique word (UW), as guard interval. We show how unique words, which are already well investigated for single carrier systems with frequency domain equalization (SC/FDE), can also be introduced...
This paper investigates the transmission in time dispersive channels of Spectrally Efficient Frequency Division Multiplexed (SEFDM) signals, where carrier orthogonality is intentionally violated in order to increase bandwidth efficiency. Sufficient statistics of the transmitted SEFDM signal can be obtained by projecting the received signal onto an orthonormal base generated at the receiver using an...
This work considers the problem of channel estimation in the context of non-binary-LDPC-coded OFDM transmission over doubly-selective multipath channels. The potential of channel encoding is exploited to derive an iterative Wiener-filter-based estimation method using both time and frequency autocorrelation of the channel. The proposed algorithm can use either the soft information or the hard decisions...
Digital Radio Mondiale (DRM) is a new digital radio broadcasting system for the frequency bands below 30 MHz. High quality audio and data transmission is achieved by adopting COFDM modulation combined with a multilevel coding scheme, which has high resistance to multipath fading and interference. In this paper, we present the algorithm design and implementation of a low-power consumption portable...
To deal with the multi-path delay spread in non- line-of-sight (NLOS) environments, single-carrier frequency- domain equalization (SC-FDE), a.k.a., single-carrier block transmission (SCBT), is thought to be an effective alternative of orthogonal frequency division multiplexing (OFDM). On the other hand, the low-density parity-check (LDPC) coding is considered as the high-performance channel coding...
This paper presents a practical low-density parity-check (LDPC) coded OFDM system designed for the underwater acoustic channel with its attendant multipath channel and large Doppler shift. The Doppler shift and channel state information (CSI) are assumed unavailable to both to the transmitter and the receiver. Due to the slow speed of sound in water, even small platform motions can affect the performance...
In this paper differential space-frequency frequency division multiplexing (MIMO-OFDM) and multiple-symbol differential detection (MSDD) without channel state information (CSI) at the receiver is considered. Inspired by previous work presented in the literature, a novel DSFM scheme is devised, which makes use of spatial and/or spectral (multipath) diversity and is particularly suited for MIMO-OFDM...
Orthogonal frequency division multiplexing (OFDM) is the modulation scheme of choice for digital video broadcasting-handheld (DVB-H), which is required to operate under high mobility conditions resulting in significant Inter-carrier Interference (ICI). To mitigate ICI, several cancellation schemes have been proposed but they require reliable channel information at the receiver which is quite challenging...
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