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Orthogonal Frequency division multiplexing is the modulation technique used for the fourth generation wireless communication system. In OFDM, Signals can be modulated by multiple carriers. OFDM uses the bandwidth of the spectrum efficiently. But the limitation of the OFDM system is the high Peak to Average Power Ratio (PAPR) which results in the degradation of the signal quality. Hence reducing the...
Block by block differential encoding is proposed for two-way relay network using amplify and forward protocol at the relays. In order to achieve bandwidth efficiency the bits are mapped into 16-ary differential amplitude phase shift keying (DAPSK) symbols. Phase estimation and reference carrier estimation at the receiver is avoided by using this non-coherent detection technique. The symbols are mapped...
This paper develops a brand new approach towards data transfer using position-modulated pulses. The core idea is to encode a data value in terms of the time gap between two transmitted pulses whose positions are modulated accordingly. It is shown that this concept allows sending a data value using significantly less number of pulses or logical bits as used in conventional packet-based transports....
In this work, we propose a link adaptation scheme called truncated channel inversion (TCI) as an effective power allocation strategy for block adaptive modulation, coding, and spatial mode (AMCS). Since water-filling based power allocation is no longer optimal to minimize bit error rate (BER) in block modulation system, block AMCS is considered as a practical link adaptation scheme. We first investigate...
Screen-camera communication, which uses a liquid crystal display (LCD) screen and camera image sensors, has been an attractive variant of visible light communications (VLC) since display and camera have been equipped with in various mobile devices. To improve transmission rates, we investigate the impact of nonlinear channel equalization and nonbinary channel coding as well as high-order modulation...
The capacity of the AWGN broadcast is achieved by superposition coding, but superposition of individual coded modulations does not in general obey a predefined constellation. We propose a coded modulation broadcast with strict channel input modulation constraint via multilevel coding (MLC). For a degraded broadcast channel, conditions of optimality of the multilevel decomposition of a superposition...
We present results on the performance of a network-coding based method for broadcast file delivery in an ad hoc network consisting of half-duplex packet radios. Our technique allows a receiver to exploit the broadcast nature of the wireless medium by overhearing packets sent by a node that is not necessarily one of the receiver's designated relays. Delivery of the file to the remote destinations is...
Direct Current (DC) line balanced SpaceWire is attractive for a number of reasons. Firstly, a DC line balanced interface provides the ability to isolate the physical layer with either a transformer or capacitor to achieve higher common mode voltage rejection and/or the complete galvanic isolation in the case of a transformer. Secondly, it provides the possibility to reduce the number of conductors...
This paper presents a comprehensive cross-layer analysis framework on the performance of transmission control protocol (TCP) over free-space optical (FSO) links, which employ the automatic repeat request (ARQ) and adaptive modulation and coding (AMC) schemes. From the framework, we quantify the impacts of different parameters/settings of ARQ, AMC and FSO links on TCP throughput performance. We also...
Media-based Modulation (MBM), introduced by Khandani, is based on bearing part of information in the variations of transmission media. However, MBM combined with forward error correction (FEC) codes is limited to hard decision decoding in the literature, which causes a performance loss. In this paper, a novel scheme is proposed, called polar coded MBM (PCMBM), to provide a higher coding gain and better...
This paper provide the performance comparison of the IEEE 802.11n and IEEE 802.11ac Wireless Local Area Network (WLAN). The IEEE 802.11ac protocol currently has been used widely. Network Simulator (NS-3) is used to simulate it. The advantages of the research using Network Simulator are shorter time to explore, low cost and flexibility on scenario developed. Our project analyzes and compares the 802...
In the past 8 years, the Centre for Maritime Research and Experimentation (CMRE) has developed, tested and promoted JANUS - a robust and simple modulation and coding scheme to be used as the first standard to support interoperability in digital underwater communications. This document aims at reporting the current status of JANUS and a first look at possible routes for evolution of this soon-to-be...
We demonstrate a novel approach for encoding images using onto a metasurface design composed of resonant dipole based unit cells. This is accomplished by varying the conductivity of individual dipole, resulting in amplitude modulation of the transmitted THz beam. However, since only a narrow regime of conductivity variation was used, the dipole array appears to be uniform visually. Thus, this offers...
The ultrafast wireless information transmission method using sliced spectral continuum in the THz frequency range, formed by a pair of THz pulses, is presented. The sliced spectral continuum contained 31 spectral lines with 23 GHz spacing in the range from 0.04 to 0.75 THz transmitted via 2 meters of free-space by common THz time-domain spectrometer. Nanoscale polycrystalline CdSxSex−1 material proposed...
Visible light communication (VLC) has recently gained popularity as a complementary technology to radio frequency (RF) based alternatives for vehicular communications as a low-cost, secure and RF interference free technology. In this paper, we propose IEEE 802.15.7 standard-compliant physical layer (PHY) implementation and experimental evaluation, using commercial off-the-shelf (COTS) automotive light...
Complexity issues and limited feedback rate strictly constraint the number of transmission modes in discrete link adaptation. A new algorithm is designed for selecting an optimum set of modes out of all the possible transmission modes based on the link's characteristics and the constraints. The design goal is to maximize the average spectral efficiency and the selection is done using a combination...
Existing finite field network coding (FFNC) can be applied in networks where all users have the same data rate and can thus use the same modulation type. In most practical scenarios, different users typically have different data rates. With simple changes such as zero-padding and repetition to the data sequences of different users received at relays, it is still possible to employ the existing FFNC...
The design of information pushing system based on visible light communication (VLC) and its optical channel performance testing were presented. The system was designed to meet requirements of some intensive conferences or special security area. The results showed that the transmission bandwidth of video signal was 500Kbps. Besides, data transmission rate of 4Mbit/s at the distance of 2.5m was achieved...
An efficient modulation and coding scheme combined with multiple LDPC codes and PPM modulation is proposed to mitigate the effect of atmospheric turbulence, which can have an unfavorable impact on the reliability of the communication link in the laser channel of the integration network of satellite and ground. The research is mainly about the reliability of the communication link under different orders...
This paper presented a multi-rate Star-QAM encoding and decoding method based on the hierarchical coding which could be adjusted to achieve the channel coding efficiency and modulation. The design is based on the combination of soft / hard decision in layered decoding. We have successfully increased BER performance to 0.5dB which achieved 10−5 when SNR is 11 compared to no stratification codec considering...
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