Topic
SC-FDE
About: SC-FDE is a research topic. Over the lifetime, 438 publications have been published within this topic receiving 7547 citations.
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TL;DR: This paper investigates the performance of Vector OFDM with linear receivers, i.e., the Zero-Forcing (ZF) and Minimum Mean Square Error (MMSE) receivers, and proves that for both ZF and MMSE receivers, all the transmitted symbols have equal performance.
Abstract: Vector Orthogonal Frequency Division Multiplexing (OFDM) for single transmit antenna systems is a general transmission scheme, where OFDM and Single-Carrier Frequency Domain Equalization (SC-FDE) can be treated as two special/extreme cases. Due to its flexibility, it has drawn more and more attention recently. So far, all the studies about Vector OFDM assume the Maximum Likelihood (ML) receiver. In this paper, we investigate the performance of Vector OFDM with linear receivers, i.e., the Zero-Forcing (ZF) and Minimum Mean Square Error (MMSE) receivers. We first show that the detection SNR gap between the MMSE and ZF receivers increases with both channel SNR and the vector blocks (VB) size defined in Vector OFDM. Then, it is proved that for both ZF and MMSE receivers, all the transmitted symbols have equal performance. This is different from the Vector OFDM with ML receiver, where different VBs may have different coding gain, and thus may have different performances. We analyze the diversity order for Vector OFDM with MMSE receiver, and show that, regardless of the Vector OFDM symbol length N, the diversity order can be represented as min{[M2-R],D}+1, where M is the VB size, R is the spectrum efficiency in bits/symbol, and D is the maximum delay of the multipath channel. For Vector OFDM with ZF receiver, we show that the diversity order equals 1 and the performance is the same as the conventional OFDM at high SNR.
55 citations
22 Apr 2003
TL;DR: Two novel schemes for reconstructing the cycle prefix for coded single-carrier frequency-domain equalization systems that employ insufficient length of cycle prefix at the transmitter are discussed and the performance of these schemes is shown by computer simulations.
Abstract: In this paper, we propose iterative methods to reconstruct the cycle prefix for coded single-carrier frequency-domain equalization (SC-FDE) systems that employ insufficient length of cycle prefix at the transmitter. Since the insertion of the cyclic prefix for SC-FDE systems decreases the bandwidth utilization efficiency as the channel's delay span increase, it is desirable to improve the bandwidth utilization efficiency by limiting the length of the cycle prefix. Two novel schemes for reconstructing the cycle prefix of coded SC-FDE systems are discussed: one employing the soft output of the soft output of the decoder and the other employing precoding. The performance of these schemes is shown by computer simulations.
50 citations
23 Apr 2007
TL;DR: A concept similar to the standard FMCW (frequency-modulated continuous wave) radar principle is used to estimate the offset in time and in frequency between two wireless communication units, allowing for a synchronization of both offsets significantly below 100 ps and 10 Hz.
Abstract: In this paper we present a novel approach for high precision clock synchronization in wireless systems. A concept similar to the standard FMCW (frequency-modulated continuous wave) radar principle is used to estimate the offset in time and in frequency between two wireless communication units. The novel approach allows for a synchronization of both offsets significantly below 100 ps and 10 Hz, respectively. This highly accurate synchronization is used in a prototype system to measure the distance between wireless units similar to a secondary radar. The prototype works within the 5.8 GHz ISM-band and uses a bandwidth of 150 MHz. With the setup presented we can measure the distance between two radio units with a standard deviation of 4 to 5 cm over a range of 200 m. This distance deviation implies a clock and center frequency synchronization of both communication modules significantly below 100 ps and 1 ppb, respectively. The broadband measurement principle is robust towards multi-path interference. It can be extended to other frequency bands and is well-suited for direct integration into communication channels and novel modulation principles such as OFDM (orthogonal frequency division multiplexing) or SC/FDE (single carrier transmission with frequency domain equalization), e.g. for locatable WLAN (wireless local area network) devices or wireless sensor networks
48 citations
TL;DR: It is shown through analysis that although SC-FDE is reasonably robust to a constant timing offset, it is fairly sensitive to random timing jitter.
Abstract: In this paper, the effects of carrier frequency offset (CFO) and sampling time offset (STO) on the performance of single-carrier block transmission with frequency-domain equalization (SC-FDE) and orthogonal frequency-division multiplexing (OFDM) over ultrawideband (UWB) channels are investigated. The signal-to-interference-plus-noise ratio (SINR) of SC-FDE in the presence of CFO is derived and compared with that of OFDM. The effects of CFO on the bit error rate (BER) performance of both systems are also simulated and compared. Two forms of STO are considered, i.e., a constant timing shift from its optimum sampling timing instant and a random timing jitter. We show through analysis that although SC-FDE is reasonably robust to a constant timing offset, it is fairly sensitive to random timing jitter. The BER performances of SC-FDE in the presence of a constant STO and random timing jitter are simulated and compared with OFDM.
42 citations
TL;DR: A mean square error (MSE) lower bound for the frequency domain LMMSE channel estimator is derived and the optimal pilot sequence that achieves this lower bound is obtained.
Abstract: Recently, single-carrier block transmission with frequency-domain equalization (SC-FDE) has been shown to be a promising candidate for ultra-wideband (UWB) communications. In this paper, we address the channel estimation problem for SC-FDE transmission over UWB channels. A mean-square error (MSE) lower bound for the frequency-domain linear minimum mean-squared error (LMMSE) channel estimator is derived, and the optimal pilot sequence that achieves this lower bound is obtained. Further simplification leads to a frequency-domain channel estimator with reduced computational complexity. The performance of the simplified estimator for SC-FDE over UWB channels is evaluated and compared with that with perfect channel state information. The effects of nonoptimal and optimal pilot symbols are also investigated. Our results show that the proposed frequency-domain channel estimator performs well over UWB channels with only small performance degradation, compared with that with perfect channel estimation
41 citations