Iterative turbo beamforming for OFDM based hybrid terrestrial-satellite mobile system

In the context of orthogonal frequency division multiplexing (OFDM)-based systems, pilot-based beamforming (BF) exhibits a high degree of sensitivity to the pilot sub-carriers. Increasing the number of reference pilots significantly improves BF performance as well as system performance. However, this increase comes at the cost of data throughput, which inevitably shrinks due to transmission of additional pilots. Hence an approach where reference signals available to the BF process can be increased without transmitting additional pilots can exhibit superior system performance without compromising throughput. Thus, the authors present a novel three-stage iterative turbo beamforming (ITBF) algorithm for an OFDM-based hybrid terrestrial-satellite mobile system, which utilises both pilots and data to perform interference mitigation. Data sub-carriers are utilised as virtual reference signals in the BF process. Results show that when compared to non-iterative conventional BF, the proposed ITBF exhibits bit error rate gain of up to 2.5 dB with only one iteration

An Integrated Approach for Future RAN Architecture

No abstract available

Energy efficiency of transmit diversity systems under a realistic power consumption model

We compare the downlink energy efficiency of spatial diversity multiple transmit antenna schemes. We determine the minimum required transmit power for a given outage probability. Our analysis shows that antenna selection is in general the most energy efficient option as it requires a single radio-frequency chain. We also investigate the limiting distances up to which the antenna selection technique outperforms the transmit beamforming scheme for different numbers of transmit antennas

Information theoretic analysis of LSD scheme

In this paper, the capacity region of Low Density Signature Multiple Access Channel (LDS-MAC) is calculated through information theoretic analysis. LDS Code Division Multiple Access (LDS-CDMA) uses spreading sequences of low density for spreading the data symbols in time domain. This technique benefits from a less complex Multiuser Detector (MUD) compared to conventional CDMA with optimum MUD; while keeping the performance close to the single user scenario for up to 200% loaded conditions. Also evaluated is the effect of different factors on the capacity of LDS MAC

Average energy efficiency contours with multiple decoding policies

This letter addresses energy-efficient design in multi-user, single-carrier uplink channels by employing multiple decoding policies. The comparison metric used in this study is based on average energy efficiency contours, where an optimal rate vector is obtained based on four system targets: Maximum energy efficiency, a trade-off between maximum energy efficiency and rate fairness, achieving energy efficiency target with maximum sum-rate and achieving energy efficiency target with fairness. The transmit power function is approximated using Taylor series expansion, with simulation results demonstrating the achievability of the optimal rate vector, and negligible performance difference in employing this approximation

Throughput analysis for cognitive radio networks with multiple primary users and imperfect spectrum sensing

In cognitive radio networks, the licensed frequency bands of the primary users (PUs) are available to the secondary user (SU) provided that they do not cause significant interference to the PUs. In this study, the authors analysed the normalised throughput of the SU with multiple PUs coexisting under any frequency division multiple access communication protocol. The authors consider a cognitive radio transmission where the frame structure consists of sensing and data transmission slots. In order to achieve the maximum normalised throughput of the SU and control the interference level to the legal PUs, the optimal frame length of the SU is found via simulation. In this context, a new analytical formula has been expressed for the achievable normalised throughput of SU with multiple PUs under prefect and imperfect spectrum sensing scenarios. Moreover, the impact of imperfect sensing, variable frame length of SU and the variable PU traffic loads, on the normalised throughput has been critically investigated. It has been shown that the analytical and simulation results are in perfect agreement. The authors analytical results are much useful to determine how to select the frame duration length subject to the parameters of cognitive radio network, such as network traffic load, achievable sensing accuracy and number of coexisting PUs

Redefining older Australians: moving beyond stereotypes and consumer narratives in print media representations

First published online November 1, 2023. OnlinePublThis paper investigates how Australian print media shape the identities of older individuals through their use of language and reporting techniques. By examining newspaper articles published between 2011 and 2021 through the lens of critical discourse analysis, the study highlights the societal, economic, and journalistic factors that influence the media's portrayal of older persons. The findings reveal that economic discourses dominate the construction of identities, with the financial reliance of older individuals on the government being a significant factor in their representation. The study demonstrates how newspapers create and disseminate narratives that appear to exonerate the government of accountability for providing aged care. Through the application of Fairclough's three-dimensional approach, this study shows how media constructs older individuals as either consumers or a burden in Australia. This study emphasises the need for print media to reflect critically on their representations of older people, avoiding harmful stereotypes and promoting positive and diverse images of ageing.Muhammad Asim Imra

News Values, Older People and Journalistic Practices in Australia and Malaysia

ANZCA Special Issue 2022This article builds on a research project examining news values, journalistic practices, and media power in Australia and Malaysia. These two countries differ from each other in socio-cultural, religious, regional, political perspectives, and journalistic practices but share the presence of indigenous people, appreciation for multiculturalism, and increasing numbers of older people. The comparison of journalistic practices – Asian-based development journalism and Western journalism practices – along with other differences, especially socio-cultural values, provides the rationale for the selection of these two countries. The study draws on Fairclough’s three-dimensional critical discourse analysis and Caple and Bednarek’s discursive news values analysis to explore the discursive practices of journalists in providing voices and prioritising different actors in news stories. 99 news articles from 8 mainstream Australian newspapers – The Age, The Sydney Morning Herald, The Australian, The Advertiser, The Daily Telegraph, The Courier-Mail, The Herald Sun, and The Canberra Times – and 5 English-language Malaysian newspapers – New Straits Times, The Malay Mail, The Star, The Borneo Post, and The Sun – published between January 2011 and December 2013 are selected as the dataset in this study. The study finds that reference to elite persons remains a uniform news value in both Australian and Malaysian newspapers, indicating the role of journalists in reflecting and reinforcing the status quo, and the imbalance of power in society. This dominant news value amongst journalists tends to silence those who are not conceived as newsworthy or seen as less newsworthy, such as older people. While the dominance of elites can be linked to social norms in Malaysia that prevent challenges to the social hierarchy and the maintenance of a high regard for people in authority such as political leaders, the discursive practices of Australian journalists do not align with their role to provide a uniform forum for the exchange of ideas, as elderly Australians are given limited opportunities to be active participants.Muhammad Asim Imra

Surface Phonon Polariton Modes in Suspended Monolayer Hexagonal Boron Nitrides

Dispersion properties and characteristics of transverse magnetic (TM) and transverse electric (TE) surface phonon polaritons (SPhP) in suspended monolayer hexagonal boron nitrides (hBN) was studied extensively. The analytical results show that the hBN based TM (TE) phonon polaritons exist in restsrahlen bands when imaginary surface conductivity is positive. The effective mode index of TM phonon polaritons is much higher than that of TE phonon polaritons with respective values of ~3000 and ~1.0002 which makes TM SPhP more promising in the practical realization. In addition, the propagation length of TE SPhP is less lossy and surpass that of TM SPhP by factor of 104. This study compares these important properties and sheds more insight into their applications in optical communications, photonics and optoelectronics devices

Skin Conductance as Proxy for the Identification of Hydration Level in Human Body

The skin dehydration level can be used to infer serious health conditions in patients since diseases like cardiovascular abnormality, diabetes and cancer symptoms do exhibit correlation with skin disorders. Therefore a systematic analysis of human skin hydration levels is critical for multiple health care applications. Motivated by this, in this study we proposed a unique approach of measuring body hydration levels against different body postures using skin conductance electrical activity. In this paper, we report the collection, processing and analysis techniques used in the analysis of skin conductance data. Subsequently in order to predict body hydration levels we employed state-of-the-art machine learning models using the skin conductance data and achieved 81.82% and 73.91% recognition accuracy for the data of standing and sitting postures,respectively using KNN model