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In this letter, we propose and experimentally investigate a training-aided iterative frequency offset estimation (IFOE) method, which can track dynamic frequency offset (FO) drift in coherent optical orthogonal frequency division multiplexing (CO-OFDM) systems. In contrast to existing FO estimation algorithms that compute specific FO values, in IFOE, only the sign value of FO is judged and recorded...
In the recent fifth generation (5G) research, filter bank multi-carrier (FBMC) technique is one of the competitive substitutes to orthogonal frequency division multiplexing (OFDM). The conventional FBMC schemes, such as FBMC staggered-modulated multitone (FBMC-SMT) and frequency spreading FBMC (FS-FBMC), have the intrinsic time-domain interference which is caused by the overlap of symbols and depend...
A new preamble structure is proposed for Narrowband Power Line Communication (NB-PLC) system, and therefore a corresponding timing estimator with interval detection and pattern matching is put forward. In the new estimator, firstly the received signals are conducted cross-correlation with the preamble in the transmitter, then the cross-correlation values are obtained and divided into several groups...
Selecting Sub-carrier Modulation (SScM) scheme, in which the information bits are used for both modulation and active-sub-carrier selection, can be used to improve Energy Efficiency (EE) without deteriorating spectrum efficiency (SE) in Orthogonal Frequency Division Multiplexing (OFDM) system. In this paper, SScM is extended to Generalized Selecting Subcarrier Modulation (GSScM) to further improve...
Channel reciprocity is an inherent feature of time division duplex (TDD) system while in frequency division duplex (FDD) system it is limited due to different frequencies being used for the uplink and the downlink. As a consequence, channel reciprocity-based secret generating methods used in TDD systems cannot be applied directly to FDD systems. In this paper, we present a novel secret key generation...
To verify the performance of communication systems, software and hardware prototypes are widely used. However, with the increasing complexity of communication systems, software prototypes cannot meet the needs of real-time operations while hardware prototypes are expensive and time-consuming to develop. Nowadays, Graphics Processing Unit (GPU) shows great prospect as a coprocessor and has the capability...
Channel reciprocity is limited in frequency division duplex (FDD) system, and thus those channel reciprocity-based secret key extraction methods which are widely adopted in time division duplex (TDD) systems can hardly be implemented in FDD systems. In this paper, a novel secret key extraction method in OFDM-FDD system is proposed to achieve physical-layer security, by which the channel frequency...
By exploiting the sparsity of the channel impulse response (CIR), compressive channel sensing methods are capable of recovering the channel state information with overwhelming probability, given that the sensing matrix holds the restricted isometry property (RIP). To this end, random pilot patterns are often assumed to ensure the RIP of the sensing matrix. In practical orthogonal frequency division...
With the tremendous growth in wireless networks market, unprecedented energy consumption and emissions of carbon dioxide (CO2) is a growing concern for both operators and governments. OFDM technology has been adopted by many standards organizations due to its high spectrum efficiency, but induces poor energy efficiency of power amplifier (PA). A new scheme named Selecting Sub-Carriers Modulation (SSCM)...
This paper investigates the problem of single-tone jamming in orthogonal frequency division multiplexing (OFDM) systems. A frequency-domain estimation and elimination scheme for single-tone interference is proposed. The proposed scheme is independent of any pilot or vacant sub carrier. Simulation results demonstrate that the proposed method is superior to the typical time-domain prediction filter...
Time-varying channel degrades the performance of LTE-Advanced system due to the Intercarrier Interference (ICI) and imperfect channel estimation. In this paper, we propose a practical strategy by bit-interleaving preprocessing in transmitting part for Doppler diversity in high-speed scenario. Time-varying channel frequency response and effect of coding rate to this algorithm are analyzed. In addition,...
In this paper we proposed a novel approach of channel estimation based on wavelet and MMSE. Recently, there have been tremendous demands for high-speed data transmission in underwater acoustic communications. Accurate channel estimation is necessary for coherent detection of the underwater acoustic orthogonal frequency division multiplexing (OFDM) signals. Pilot-assisted channel estimation using training...
In this paper we proposed a novel approach of blind channel equalizer for underwater multiple-input multiple-output orthogonal frequency diversity multiple (MIMO-OFDM) system. Convolutional encoder is applied on reference frequency bin and each block before entre the underwater MIMO-OFDM system. The transform imposed a correlation structure on the transmitted block, after every reference frequency...
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