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Higher data rates and better Signal to Noise Ratio (SNR) are the key factors for contemporary broad-band applications of next generation wireless communications. Robustness to multipath effects impaired by the channel is the guaranteed motto of Orthogonal Frequency Division Multiplexing (OFDM). Forward Error Control Codes (FEC) like the Convolution encoder and the Viterbi decoders are used to enhance...
The spectral efficiency of cellular communication systems is limited by inter-cell interference. Especially cell edge users will experience bad performance. A potential remedy to inter-cell interference is joint signal processing on the base station (BS) side. In the cellular uplink the received signals of multiple BSs can be processed at a central node, referred to as joint detection (JD). Field...
Recently the demand for high data rate has been increasing along with the need to connect many users to an access point (AP) or a base station (BS). In this paper, we propose a bit-interleaved coded multi-user multilevel modulation (MU-MLM) for orthogonal frequency division multiple access (OFDMA) systems. MU-MLM is multilevel modulation (MLM) incorporating multiple users at each modulated symbol...
Maximum likelihood detection (MLD) has been shown to offer large performance gains within the context of linearly precoded MIMO-OFDM systems with multiple-stream transmission when compared to an all-linear setup (i.e., linear transmitter/receiver), although at the cost of a higher computational complexity. To overcome this handicap, this paper proposes a method to selectively choose the detection...
Channel estimation is a crucial task for the overall communication performance of a wireless receiver. Compared to traditional approaches the estimation of the wireless channel can be improved by using iterative estimation with feedback from other receiver components, however the VLSI implementation of such iterative channel estimation in multiple-input multiple-output (MIMO) orthogonal frequency...
Parallel Sequence Spread Spectrum (PSSS) is a physical layer (PHY) base band technology. It was selected for the wireless sensor network standard IEEE802.15.4-2006, in order to increase data rate and radio performance in fading channels for frequency bands below 1GHz. In the work presented in this paper PSSS is used for the first time in the 60 GHz ISM Band to achieve ultra-high transmission speed...
We present the use of visible light as an alternative to wireless radio communication. We use common data encryption techniques followed by modulation of the signal using Orthogonal Frequency Division Multiplexing. The modulated signal is used to drive common Light Emitting Diodes which transmit a binary bit-stream in the form of light, through air as the medium. A photo detector, used at the receiver,...
Channel estimation is a crucial task for the overall communication performance of a wireless receiver. Compared to traditional approaches the estimation of the wireless channel can be improved by using iterative estimation with feedback from other receiver components, however the VLSI implementation of such iterative channel estimation in multiple-input multiple-output (MIMO) orthogonal frequency...
Software Defined Radio platforms are a flexible and cost efficient solution to deal with the increasing number of today's wireless communication standards. One interesting use case can be found in the automotive industry where the IEEE 802.11p standard enables Car-to-Car and Car-to-Infrastructure communication. In the context of this paper we present a physical layer implementation of the 802.11p...
In what follows the problem of finding upper bounds on denial probability and probability of erroneous decoding in a coded Dynamic Hopset Allocation Frequency Hopping system with noncoherent threshold reception is considered
Coded cooperation is an attractive user cooperation scheme for wireless systems, where different parts of a coded packet are transmitted over different channels. In this paper, we propose a new approach to improve the performance of coded cooperation. We present cooperative maximum-ratio combining (C-MRC) based coded cooperation to guarantee full diversity even if the inter-user link is not ideal...
The investigation of MIMO technology with OFDM has recently been the focus of extensive research. The main objectives of this technology are to improve bandwidth efficiency and bit error rates. In this paper, we propose an approach for high data rate communication systems. Our approach incorporates the turbo and space-time-frequency coding approaches. The proposed space-time-frequency turbo code (STF-TC)...
To meet the requirements of the COFDM (coded orthogonal frequency division multiplexing) wireless video transmission system for real-time and high-quality transmission of video signals, in this paper, we take Turbo code as the channel coding of COFDM system because of its superior performance. COFDM wireless video transmission system is briefly described at first, then detailed describe the encoding...
Interference alignment (IA) has been shown to achieve the maximum degrees of freedom in the multiple-input multiple-output (MIMO) K-user interference channel (IFC). In the presence of frequency-selective channels, orthogonal frequency-division multiplexing (OFDM) is typically used to deal with the multipath nature of the channel. While IA techniques can be applied in a per-subcarrier basis (post-FFT),...
In this paper, a spatially multiplexed orthogonal frequency division multiplexing multiple input multiple output (SM-OFDM-MIMO) IEEE 802.11n system is assumed. The 802.11n system performance is comparatively analyzed implementing either linear minimum mean squared error (MMSE) receiver or MMSE ordered successive cancellation (MMSE/OSIC) receiver with both hard and soft decision Viterbi decoding over...
Coordinated multi-point (CoMP) processing is a key technique in next generation mobile communications. It can effectively solve the interference problem encountered in cell edges. To conduct the processing, however, base stations need to exchange users' informations, yielding a communication overhead for the backhaul. This paper considers inter-site uplink CoMP processing for multi-input-multi-output...
To facilitate practical implementation of a dynamic decode-&-forward (DDF) for type-2 user equipment (UE) relay defined in 3GPP which is being considered for next-generation cellular standards (e.g., LTE-Advanced), we propose “Modified Dynamic DF (M-DDF)” to realize fast jump-in relaying and decoding scheme for cooperative transmission. More specifically, subframe based sequential decoding is...
This paper addresses the concatenation of a convolutional code and COFDM/OQAM modulation transmitted over a time-dispersive radio channel. The proposed receiver is composed of a suitable OFDM/OQAM filter-bank demodulator, followed by an intersymbol and inter(-subchannel) interferences canceller and a SISO (Soft Input - Soft Output) decoder put in Turbo-like mode. The iterative algorithms are based...
This paper deals with the DVB-T (Digital Video Broadcasting-Terrestrial) and DVB-T2 (DVB-2nd Generation Terrestrial) standards and their transmission performance in fixed TV channels. For the analysis and simulation of performance of both standards, classical Ricean and Rayleigh multipath fading channels with 20 independent paths were used. Simulation results of the BER (Bit Error Ratio) before and...
In this paper, a novel configuration of VLC system based on sub-carrier multiplexing of MISO OFDM is proposed. The system consists of a 2×1 MISO array of white LEDs to transmit and receive data. The data is respectively modulated by two sub-carriers at 6.25MHz and 12.5MHz. An overview of the system configuration is described, and the transmission experiment is setup. The experimental results and the...
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