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In order to address a wide variety of future requirements, Generalized Frequency Division Multiplexing (GFDM), a non-orthogonal multicarrier scheme, is considered as one of the most promising techniques available today. To improve the orthogonality of the conventional GFDM system, a multi-taper implementation of GFDM (MGFDM) using discrete prolate spheroidal sequences (DPSSs) or multi-tapers, which...
We study the information rates of several unipolar orthogonal frequency division multiplexing (OFDM) schemes in discrete-time Gaussian optical intensity channels under average optical power constraint. All our results are derived under the assumption that i.i.d. complex Gaussian codebook ensemble and nearest neighbor decoding (minimum Euclidean distance decoding) are used. Results for single-component...
The characteristics of underwater acoustic channel is strong multipath, severe Doppler and limited bandwidth. OFDM modulation has good ability in anti multipath and Turbo Product Codes(TPC) has excellent performance in a high code rate, We make full use of their advantages and designed an OFDM underwater acoustic communication system based on TPC. Using the BELLHOP simulation model to get the approximate...
Although Orthogonal Frequency Division Multiplexing (OFDM) seems to be a solution to achieve the demand of high data rates and immunity to the multipath fading channel, it has some drawbacks. High Peak to average power ratio (PAPR) is the most significant problem of these drawbacks. The main objective of this paper is to introduce a modified PAPR reduction technique named as samples clipping and then...
A novel hybrid orthogonal frequency division multiplexing (H-OFDM) technique, for 5G candidate waveforms, has been proposed to improve the performance of conventional OFDM systems in this paper. In H-OFDM system instead of conventional cyclic prefixes (CPs) it is used hybrid CP as a guard interval. The hybrid CP consists of zero tail (ZT), unique word (UW) and CP. Computer simulations have been performed...
First and second generation digital video broadcasting terrestrial systems (DVB-T and DVB-T2/T2-Lite), like many other wireless communication standards, contain an Orthogonal Frequency Division Multiplexing (OFDM) signal processing chain. One of the main disadvantages of the OFDM technique is its high sensitivity to the non-orthogonality between In-Phase and Quadrature (IQ) signals in the IQ modulator/demodulator...
A reliable feedback channel is vital to report decoding acknowledgments in retransmission mechanisms such as the hybrid automatic repeat request (HARQ). While the feedback bits are known to be costly for the wireless link, a feedback message more informative than the conventional single-bit feedback can increase resource utilization efficiency. Considering the practical limitations for increasing...
In this paper, we propose a simple and efficient soft- in soft-out (SISO) equalization for block Markov superposition transmission (BMST) in the coded OFDM system (called BMST-OFDM) over high-mobility wireless communication channels. In the BMST-OFDM system, the proposed SISO equalizer can exchange soft messages with the soft demapper and the BMST decoder in an iterative fashion. Simulation results...
With the development of high-speed trains (HST), efficient and reliable communication services in high mobility scenarios have become an urgent demand. As one of the strong candidates in 5G wireless system, polar codes along with its optimized design should also be investigated under high mobility scenarios. In this paper, a scheme of hash-concatenated polar codes is proposed to reduce the false alarm...
This paper considers a multicarrier faster-than-Nyquist (FTN) transceiver architecture when spectrally efficient frequency division multiplexing (SEFDM) is also utilized at the transmitter. The received symbols are corrupted by both the introduced inter-symbol interference (ISI) due to FTN and inter-carrier interference (ICI) due to SEFDM. The interferences have to be eliminated to recover the transmitted...
In this paper, alternative signal set designs for higher order constellations based on combinatorial structures are proposed. These system designs are practical for 5th and future generation of systems. Non-Orthogonal Multiple Access (NOMA) is currently recognized as a promising multi-access technique for fifth generation (5G) networks. NOMA techniques ensure that multiple users share the same spectrum...
Recently, rateless codes make a remarkable progress on achieving maximum network performance without incurring CSI feedback overhead, under dynamic contexts with time-varying channels. However, existing rateless codes are only optimal for single-carrier channels, but are far from optimal for multi-subcarrier OFDM channels that are dominantly adopted in modern high-speed wireless networks. In this...
Machine-to-machine (M2M) communications play an important role for applications that involve connections between a massive number of heterogeneous devices in home and industrial networks. For M2M networks, realizing low latency and high reliability is of great importance. In this paper, we show the great potential of polar-coded orthogonal frequency-division multiplexing (OFDM) to fulfill those requirements...
This paper presents an improvement to the end-to-end bit error rate (E2E-BER) performance of turbo-coded orthogonal frequency division multiplexing for physical layer network coding (TC-OFDM-PLNC) over power line communication (PLC) channels in the presence of impulsive noise. A novel detection scheme is introduced to transform the transmit signal constellation based on the frequency-domain channel...
A cyclic prefix orthogonal frequency division multiplexing (CP-OFDM) system that transmits information over a time-varying fading channel is considered. In channels with large Doppler spreads, the frequency orthogonality assumption of OFDM is not valid. Hence, inter-carrier interference (ICI) is introduced, which leads to higher bit error rates (BERs). We propose a channel equalizer based on the BCJR...
In massive MIMO systems, multiple high-speed high-resolution ADCs will be a major obstacle for real applications because of the hardware complexity and power consumption. One solution to this problem is to adopt low-cost low-resolution ADCs instead. Note that highly quantized signals will destroy the orthogonality of OFDM design, the key point remains to find computational decoding methods while maintaining...
Orthogonal Frequency Division Multiplexing, together with Multiple-Input Multiple-Output, is a pillar technique for new generation mobile networks, i.e., for the mobile networks in direction of 5G. Its crucial properties of robustness against fading and Inter-symbol Interference make it a great choice for the demanding data rates of future mobile networks. This paper presents a technique for additional...
Filter bank multi-carrier with offset quadrature amplitude modulation (FBMC/OQAM) is considered as a promising alternative to orthogonal frequency division multiplexing with the cyclic prefix insertion (CP-OFDM). In this paper, a MIMO-FBMC using turbo code is proposed and a comparison is made between turbo coded MIMO-OFDM and turbo coded MIMO-FBMC systems. The evaluation of bit error rate and signal-to-interference...
In this paper, we propose a new baseband architecture for Internet of Things (IoT) terminals that support long range communications such as those based on Orthogonal Frequency-Division Multiple Access (OFDMA) and spread spectrum technologies. We analyze the workload profiles of both systems and find that the frame detection unit has by far the highest computational load. Based on this analysis, we...
Due to their lack of assessment mechanisms of link quality in VANET environments, routing protocols do not deal efficiently with highly volatile links. One way to fill this gap would be to anticipate links breakages with new route computation. Currently available link quality indicators are not sufficiently responsive to consider forecasting. In this paper we present a novel predictive link quality...
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