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In this paper, we focus on the design of a reliable communication scheme for generic 5-node wireless butterfly networks (WBN). Since the WBN represents a natural extension of the basic two-way relay communication channel, we follow the paradigm of Wireless Physical Layer Network Coding and we show that the design of novel adaptive constellations is desirable to exploit the promising performance of...
5G systems aim to achieve extremely high data rates, low end-to-end latency and ultra-low power consumption. Recently, there has been considerable interest in the design of 5G physical layer waveforms. One important candidate is Generalised Frequency Division Multiplexing (GFDM). In order to evaluate its performance and features, system- level studies should be undertaken in a range of scenarios....
The global move toward wireless access point (AP) densification has alluded toward the possibility of harvesting the unused ambient RF energy, especially in the 2.4-GHz unlicensed band, in order to power useful electronic devices, which collectively make up the so-called low energy Internet of Things (LE-IoT). Despite the huge market demand for free ambient energy and the research community’s efforts...
A wireless relay node employing Wireless Physical Layer Network Coding (WPLNC) must use a specific mapping in order to combine incoming signals. This mapping, however, cannot be selected arbitrarily. Together with the signals from the other network relays, it has to allow the destinations to be able to recover the source data from the available observations. Moreover the mapping should optimize a...
Wireless Physical Layer Network Coding (WNC) techniques exploit the inherent nature of wireless channels to improve the performance of wireless communication systems. Unlike conventional Network Coding, in WNC the transmitted signals constructively interact directly in the constellation space, thus inducing specific requirements on the source constellation design. Suitable multi-source constellations...
This paper presents a novel Time Domain (TD) based Multiple-Input Multiple Output (MIMO) implementation of the Expectation-Maximization (EM) algorithm. The algorithm is able to achieve Maximum Likelihood (ML) performance with reduced complexity. Results show how performance superior to the Recursive Least Square (RLS) algorithm, in terms of both convergence and residual Mean Squared Error (MSE), can...
In this paper, we analyze the symbol-error rate of a two-hop fixed-gain amplify-and-forward OFDM relay network when nonlinear distortion, as a consequence of relay amplifier saturation, is considered at the relay. We begin by constructing a theoretical model of the system. Due to the Gaussianity of OFDM waveforms, we are able to employ Bussgang's theorem in our model, which enables the calculation...
The antenna performance of three 2×2 802.11n wireless routers is assessed at 2.4GHz using a laptop as a reference client. The analysis combines in-situ measured 3D radiation patterns with state-of-the-art 3D ray-tracing for a number of different client locations and access-point/client orientations in a typical three-floor home. A router employing two PIFAs achieves the highest average signal level...
In this paper the relative performances of antenna elements are assessed by combining the measured full (3D) far-field radiation patterns of each with measured angle of arrival data for a laboratory/office space. Three element types (Cavity-backed Slot, Printed Inverted-F and Dielectric Resonator) at two positions on a small mobile terminal are considered, and the terminal is tilted and rotated in...
Throughput and packet error rate are analysed in a home environment for two different 3x3 wireless LAN solutions. A 3x3 EBF approach (using three radio chains) is compared with a reduced cost 2x2 architecture (using two radio chains). In the 2x2 solution the optimum antenna pair is selected from the same set of three antennas at the AP and client. The impact of directional, as well as omni- directional,...
In this paper the throughput and packet error rate for an in-home 802.11n network is theoretically derived for two different types of 3x3 antenna configurations. Our first configuration assumes the use of three low directivity omni-dectional elements. The second arrangement makes use of three orthogonally orientated directional elements. The spatial and temporal characteristics of the in-home channels...
This paper explores rules and defines cross layer parameters that enhance the received video quality per unit bandwidth while observing strict video QoS for unicast video transmission over mobile WiMAX. Channel capacity and goodput are estimated using a detailed MAC/PHY simulator. The simulator supports link adaptation of the PHY layer Modulation and Coding Scheme (MCS) alongside MAC layer Automatic...
This paper presents results from a novel OFDMA multi-cell mobile broadband system-level simulator. The tool is used to statistically characterize uplink and downlink inter-cell interference. Fully loaded interference studies cannot be performed on real-world networks until they have been fully deployed. As such, interference analysis and management must be accurately performed pre- deployment using...
This paper addresses the multicast capabilities of WiFi systems transmitting to handheld devices in outdoor public spaces. The analysis includes a comparison of access point antennas in terms of received signal strength for different conditions and handset orientations. An H.264 AVC encoder and IP packetisation unit is used to multicast IP video streams to WiFi enabled mobile clients. Measurement...
This study aimed to measure changes in household water lead and blood lead in young people living in Edinburgh over a period of 8 years. Two hundred and twenty-three families were eligible and 207 (93%) agreed to participate. A half-hour stagnation sample of kitchen cold water was taken from each household, and 171 young people (aged 14–17 years) provided a blood sample for lead analysis. Information...
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