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Sleep monitoring system helps to diagnose various health problems. Traditional solutions for sleep monitoring are usually invasive or limited to medical facilities. Radio Frequency (RF) based methods require specialized devices or dedicated wireless sensors. Recently, Wi-Fi based methods without any wearable or dedicated devices obtain more attention, however, they all assume that all the users are...
The channel impulse response (CIR) under indoor stair environment is modeled. In this model, the amplitude and phase of the CIRs are described as Weibull and uniform distributed random variables, respectively. The CIRs can be simulated using the proposed model. Then, Orthogonal Frequency Division Multiplexing (OFDM) communication system is implemented on the measured and simulated channels. Based...
This paper presents a channel coding scheme for OFDM with 64-QAM and 256-QAM over Rayleigh channel. In our proposed scheme, the OFDM system employs three mode of IFFT with 4k, 16k, and 32k. In addition, the concatenated coding scheme of LDPC and BCH code is utilized as channel code referring to the standard from ETSI EN 302 755. Aside from the simulation, we also measure the system performance via...
This paper presents a robust concatenated coding scheme for OFDM with 64 QAM over AWGN channel. At the forward error correction unit, our proposed concatenated coding scheme employs standard form of BCH code as outer code and LDPC code as inner code. Varying from the code rates of BCH codes, we can find the minimum requirement of signal to noise ratio in the proposed concatenated coding scheme. In...
Subspace methods have been widely used in blind channel estimation of MIMO-OFDM system. However, direct subspace decomposition suffers from heavy computation complexity of o(N)³. In this paper, a new data projection method (DPM) based principal and minor subspace tracking algorithm is presented by exploiting a novel orthonormalization matrix. The new algorithm exhibits good numerical stability and...
In this paper, the truncated singular value decomposition expectation-maximization (TSVD-EM) based channel estimation on single transmit antenna transmission is extended to transmit diversity transmission. Particular attention is given to Long Term Evolution (LTE) systems. In order to obtain the received symbols for each transmit antenna, an approximation is proposed by using the soft symbols and...
We propose a novel discrete spectrum-scan routing scheme in flexible optical networks. Based on spectrum discretization, this scheme achieves optimal routing in a gridless network scenario while reducing the routing complexity from exponential to polynomial.
In this paper, an iterative channel estimation algorithm is considered in LTE systems. A simplified expectation maximization (EM) based algorithm is proposed for channel estimation in the frequency domain. In order to deal with “null” sub-carriers in the guard band and make the algorithm simpler, the truncated singular value decomposition method is integrated to EM (TSVD-EM). Together with a simple...
This work proposes an adaptive frequency-domain equalizer (FDE) for single carrier and OFDM indoor over Gbps data rate wireless receiver. System simulation and specifications are based on the IEEE 802.15.3c standard. The proposed LS-LMS FDE uses low computational complexity Least-Mean-Square (LMS) algorithm with Least-Square (LS) channel estimation to accelerate the convergence speed. The FDE can...
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,...
This paper gives an overview of the objectives and current research activities on interference exploitation in the EC funded research project ARTIST4G. Focus is on channel estimation and multi-cell joint processing. First field trial results for different cooperation schemes are provided.
As good candidates for uplink multiple access scheme in broadband wireless communication systems, orthogonal frequency division multiplexing (OFDM) and single-carrier (SC) with frequency division multiple access (FDMA) have gained enough attention recently. However, the non-linearity of amplifier deteriorates the performances of these two schemes. On the assumption of non-linear amplifier applied,...
Multiuser diversity can significantly improve wireless system performance by exploiting the feedback information that conveys the channel quality. In multiple input-multiple output and orthogonal frequency division multiplexing (MIMO-OFDM) systems, the per subcarrier on per antenna feedback induces a substantial amount of feedback overload and requires high computational complexity. This paper addresses...
In this paper, we demonstrate that SC-FDE has different error characteristic from OFDM. Accordingly, we point out that both comparisons of coded BER between OFDM with block interleaving and SC-FDE in the classical literatures are unfair. And then, we propose a new coding scheme, which could take the advantage of the constraint of the coded information bits, for SC-FDE. Convolutional codes with different...
A novel robust bit loading algorithm with uniform power constraint under desired rate for OFDM is proposed. In this algorithm, only strong subchannels are used to transmit data .The number of active subchannels is determined by a criterion named capacity criterion, then power is allocated among active subchannels. The most significant novelties of this algorithm are that two modulation schemes are...
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