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Beamforming (BF) is an effective method to restrain interference in cellular communication systems. Steering beam direction in 3D space can improve useful signal power that user equipments (UEs) received and eliminate interference effectively. In this paper, we focus on how to choose 3D-BF angles of beam and propose a cooperative angle selecting scheme based on maximum signal to leakage plus noise...
The present random access (RA) scheme in terrestrial LTE (T-LTE) cannot be applied in LTE-satellite system, for the remarkable miss detection probability caused by large difference of propagation delay in satellite communication system. In this paper, a Peak to Average Ratio after Deleting Quasi-users (PAR-DQ) detection algorithm is proposed. The algorithm can deal with the large difference of propagation...
Employing the low bitwidth, e.g. 1 bit or 2 bit analog-to-digital converter (ADC) can remarkably reduce the high power dissipation of ADC in the orthogonal frequency division multiplexing (OFDM) communications. However, the biterror-rate (BER) performance will be considerably undermined. In the paper, through deliberately reserving the subcarrier at the transmitter, the quantization distortion can...
In tone reservation (TR) methods, the high peak-to-average power ratio (PAPR) of orthogonal frequency division multiplexing (OFDM) signals is reduced through exploiting the reserved tones, i.e., peak-reduction tones (PRT), so as to manipulate the clipping noise generated from the soft limiter with predefined clipping threshold. In this work, from the least-squares perspective, the PRT are designed...
LTE system will share the same frequency band with fixed-satellite service (FSS) in 3400 ~ 3600 MHz, which has been identified as one of the candidate bands for the future development of mobile systems. In this paper, deterministic analysis and Monte Carlo simulation are adopted to study the co-existence of two systems in 3400~3600 MHz based on the FSS parameters in China. In deterministic analysis,...
Time-of-arrival (TOA) estimator design for impulse radio ultra-wideband (IR-UWB) ranging demands high sampling rate high resolution ADC, which is difficult to implement. Some tradeoffs can be made such as limiting amplitude resolution. In this paper, we propose a two-step threshold selection TOA estimator using a two-bit ADC. The quantization threshold of ADC is set as the coarse threshold to distinguish...
In this paper, a novel channel estimation scheme called Two-Pilot Estimation (TPE) is proposed for distributed space-time decoding in Amplify-and-Forward (AF) based wireless relay networks. For Maximum Likelihood (ML) decoding at the destination, directly estimating the product of source-relay (S-R) channel and relay-destination (R-D) channel either is difficult, or causes drastic receiver degradation...
In this paper, we investigated the impacts of temporal noise and spatial noise on video traffic characteristics. Our study demonstrated that the noise of camera seriously changes the features of motion JPEG sequences and MPEG sequences. The results of experiment can be used for traffic modeling. In addition, we found that the idea of differential is not suit for low signal-to-noise ratio environments.
In this paper, we study optimum SNR threshold based partial decode-and-forward (PDF) schemes where relays may choose to forward the demodulated symbols in form of distributed space-time coding (DSTC) or to remain silent according to instantaneous link qualities of the source to relays. Considering the possible error of Maximum likelihood decoding at intermediate relays, we model a general noise in...
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