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A link adaptation scheme for MIMO-OFDM systems over high speed rail environment is addressed in this paper. In this study, a selection method of MIMO transmission mode and the modulation and coding scheme (MCS) according to the Rician channel K-factor from our previous work is considered. A hidden Markov model of time-varying Rician channel K-factor is constructed by using the real measured channel...
This paper focuses on a multiple input multiple output (MIMO) orthogonal frequency division multiple (OFDM) system, which uses space frequency block coding (SFBC) and an intercarrier interference (ICI) estimation/mitigation module for high mobility environment. The proposed algorithm is with low complexity which is proportional to O(N) (instead of O(N3)) and flexibly to apply to single input single...
Hierarchical modulation provides layered transmission and is a very promising mechanism to reliably provide basic services to receivers with various reception conditions. Because the high priority layer is allocated with more power, the low priority layer is vulnerable to noise and interference. This paper applies a repetition coding to either of the layers of hierarchical modulation to cancel the...
Hybrid transport system employing half-split-band and remote light injection techniques is proposed and demonstrated. Over an 80-km SMF transmission, good performances of CNR, CSO, CTB and BER were obtained for CATV and 16-QAM OFDM band.
This paper presents a link adaptation scheme for the MIMO-OFDM system to achieve high spectral efficiency in a required BER performance. The modulation order and MIMO transmission mode are selected via a look-up table according to the SNR and Rician channel K-factor instead of the channel relative condition number. The BER and spectral efficiency performance of the MIMO-OFDM system is evaluated by...
This paper proposes a packet retransmission scheme with interference cancellation for OFDM systems based on the basic principle of spread spectrum technique. The proposed design orthogonally spreads packets in transmission-domain to separate the desired signal from the interferences. Almost without increasing complexity, it outperforms the conventional packet retransmission scheme.
Based on the basic principle of spread spectrum systems, this paper proposes a hybrid automatic-repeat-request (HARQ) scheme with interference mitigation for multiple-input-multiple-output (MIMO) orthogonal frequency-division multiplexing (OFDM) systems. The proposed hybrid media access control (MAC) and physical layer (PHY) design orthogonally spreads signals in the transmission domain to separate...
Based on the principle of spread spectrum systems, this paper presents a hybrid automatic-repeat-request (HARQ) scheme with the mitigation of intercarrier interference (ICI) by orthogonally encoding transmitted signals on subcarriers for orthogonal frequency division multiplexing (OFDM) systems. The proposed scheme not only increases the signal-to-noise ratio (SNR) but also reduces the ICI. Simulations...
This paper presents the mobile receiving performance based on measured DVB-T signals. During mobile reception, the OFDM system suffers ICI because of time- varying channel. In this paper, the ICI effect is reduced in time domain utilizing the ISI-free region by using receiver windowing method with Franks window coefficients. The partial ensemble correlation symbol timing synchronization algorithm...
In wireless communication, the channel response may vary rapidly when the user's mobility is high. Since pilot signals are usually limited, channel estimation often involves interpolation. How to perform channel interpolation/estimation in high-mobility scenario is then a challenge problem. This is particularly true for an OFDM system operated in long-delay- profile channels. In this paper, we consider...
In this paper, we consider the ICI effect induced by time-varying channel. A simple and low-complex method is proposed to suppress ICI by windowing the received signal using Franks window coefficients in time domain and combining the extended signal interval which was not interfered by multipath to the corresponding information part of the cyclic-prefix (cp) based OFDM system. The ICI are suppressed...
The purpose of this work is to design a wideband DTV (Digital TV) antenna with a multiple-structure of transmission line antenna. A technique of varying the width of transmission line antenna is developed firstly to shorten its length. By adding three individual transmission line antenna with different bands together, a wideband characteristics is achieved in the UHF band. This is suitable for digital...
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