Implementing Enhanced MIMO with F-OFDM to Increase System Efficiency for Future 5G Cellular Networks

The upcoming fifth generation of cellular communication system is most likely to be deployed by the year 2020. The new generation of mobile network is expected to have high data rates, low latency and support a huge number of devices. Aside from this, machine type communication (MTC) and internet of things (IoT) are expected to be handled by 5G system in a better and efficient way. For this reason, a number of waveform candidates have been proposed. Filtered orthogonal frequency division multiplexing (F-OFDM) is one of the proposed candidates for 5G systems, which highly resembles to its predecessor that is orthogonal frequency division multiplexing (OFDM). The crucial difference between the two multicarrier waveforms is the use of a well-designed filter. F-OFDM in comparison with OFDM thus provides reduced out of band emission, which enables it to utilize the allocated spectrum efficiently. This research paper provides a brief review of F-OFDM performance with multiple input multiple output (MIMO) implementation. Using MATLAB, the MIMO system with F-OFDM has been tested for different configurations such as SIMO (receive diversity) and MISO (transmit diversity) with different digital modulation schemes including QPSK, 16-QAM, 64-QAM and 256-QAM. The bit error rate (BER) vs the signal to noise ratio (SNR) plots judge the performance of the system

Hybrid routing scheme for vehicular delay tolerant networks

In Vehicular Delay Tolerant Networks (VDTN) connection from source to destination at any required period is not necessarily available. Therefore, the node with the message, save it in its own buffer and carry it until an opportunity comes across for forwarding. Fix nodes enhances the performance of VDTN. It helps in message storage and relaying messages. Due to mobility the bit error rate is high in mobile nodes connection but it is not considered in any of the previous routing schemes for VDTN. The connection between fix nodes will always have low bit error rate as compared to connection involving mobile nodes. All the pervious schemes are one dimensional. Environmental hindrances are not taken under consideration as well. Its effect can be both negative and positive. In this paper, a scheme titled Hybrid routing scheme is suggested to overcome the above stated problems. Features of another vehicular network called Vehicular Ad Hoc Networks (VANETs) are added to Maximum Priority (MaxProp) routing scheme for VDTN. Different propagation models of VANETs are implemented for both with and without mobile node communication for VDTN. The concept of bit error rate is also featured in Hybrid routing scheme. This makes Hybrid routing scheme two dimensional and more intelligent. The implementation and performance assessment of the proposed scheme is evaluated via Opportunistic Network Environment (ONE) Simulator. The Hybrid routing scheme outperform MaxProp in terms of the delivery probability and delivery delay

Blind convolutive speech separation and dereverberation

Extraction of a target speech signal from the convolutive mixture of multiple sources observed in a cocktail party environment is a challenging task, especially when the room acoustic effects and background noise are present in the environment. Such acoustic distortions may further degrade the separation performance of many existing source separation algorithms. Algorithmic solutions to this problem are likely to have strong impact on many applications including automatic speech recognition, hearing aids and cochlear implants, and human-machine interaction. In such applications, to extract the target speech, it is usually required to deal with not only the interfering sound, but also the room reverberations and background noise. To address this problem, several methods are developed in this thesis. For the blind separation of a target speech signal from the convolutive mixture, a multistage algorithm is proposed in which a convolutive independent component analysis (leA) algorithm is applied to the mixture, followed by the estimation of an ideal binary mask (IBM) from the separated sources obtained with the convolutive leA algorithm. In the last step, the errors introduced due to estimation of the IBM are reduced by cepstral smoothing. The separation performance of the above algorithm, however, deteriorates with the increase in surface reflections and background noise within the room environment. Two different methods are therefore developed to reduce such effects. In the first method which is also a multistage method, acoustic effects and background' noise are treated together using an empirical-mode-decomposition (EMD) based algorithm. The noisy reverberant speech is decomposed adaptively into oscillatory components called intrinsic mode functions (IMFs) via an EMD algorithm. Denoising is then applied to selected high frequency IMFs using an EMD- based minimum mean squared error (MMSE) filter, followed by spectral subtraction of the resulting denoised high and low-frequency IMFs. The second method is a two-stage dereverberation algorithm in which the smoothed spectral subtraction mask based on a frequency dependent model is derived and then applied to the reverberant speech to reduce the effects of late reverberations. Wiener filtering is then applied such that the early reverberations are attenuated. Finally, an algorithm is developed for joint blind separation and blind dereverberation. The proposed method consists of a step for the blind estimation of reverberation time (RT). The method is employed in three different ways. Firstly, the available mixture signals are used to estimate blindly the RT, followed by the dereverberation of the mixture signals. Then, the separation algorithm is applied to these resultant mixtures. Secondly, the separation algorithm is applied first to the mixtures, followed by the blind dereverberation of the segregated speech signals. In the third scheme, the separation algorithm is split such that the convolutive leA is first applied to the mixtures, followed by the blind dereverberation of the signals obtained from convolutive leA. Then, the T-F representation of the dereverberated signals is used to estimate the IBM followed by cepstral smoothing.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

JOINT BLIND DEREVERBERATION AND SEPARATION OF SPEECH MIXTURES

ABSTRACT This paper proposes a method for jointly performing blind source separation (BSS) and blind dereverberation (BD) for speech mixtures. In most of the previous studies, BSS and BD have been explored separately. It is common that the performance of the speech separation algorithms deteriorates with the increase of room reverberations. Also most of the dereverberation algorithms rely on the availability of room impulse responses (RIRs) which are not readily accessible in practice. Therefore in this work the dereverberation and separation method are combined to mitigate the effects of room reverberations on the speech mixtures and hence to improve the separation performance. As required by the dereverberation algorithm, a step for blind estimation of reverberation time (RT) is used to estimate the decay rate of reverberations directly from the reverberant speech signal (i.e., speech mixtures) by modeling the decay as a Laplacian random process modulated by a deterministic envelope. Hence the developed algorithm works in a blind manner, i.e., directly dealing with the reverberant speech signals without explicit information from the RIRs. Evaluation results in terms of signal to distortion ratio (SDR) and segmental signal to reverberation ratio (SegSRR) reveal that using this method the performance of the separation algorithm that we have developed previously can be further enhanced

Investigating circular economy and sustainability marketing in the gulf: the case of UAE

Gulf countries are known for their high levels of consumption with the United Arab Emirates (UAE) topping the list. The per capita consumption rate of the UAE is reported to be over USD 21675 per person in 2021. This alarmingly high rate of consumption comes with the cost in the form of environmental decimation. Usually, marketing is considered the main culprit behind the high rate of consumption, as it usually encourages people (customers) to buy, use, and upgrade frequently. However, this is not entirely true because of the latest paradigm in marketing, which is, “Sustainability Marketing”. The concept of the “Circular Economy” and “Sustainability Marketing” could be used to mitigate this issue of environmental turndown through exploration, investigation, and education of these emerging concepts, especially, in the Gulf region. Circular economy and sustainability marketing are closely related concepts where the focus is on meeting the needs of the present without compromising the ability of future generations to meet their own needs through closed-loop systems. In this process, the waste is eliminated, and resources are conserved through reuse, repair, refurbishment, and recycling. Interestingly, these marketing philosophies are also aligned with the Islamic behaviour of moderation and avoiding wasteful spending and could be used as the potential driving forces to further enhance the concepts of circular economy and sustainability marketing. The present study attempts to undertake the same challenge in proposing and empirically investigating a comprehensive model of the circular economy and sustainability marketing in the Gulf by using the UAE as a representative case of the GCC countries. For this purpose, factors related to consumer intention have been extracted from the extensive review of the marketing literature. In this case, the underlying theory deemed appropriate was the Theory of Planned Behaviour (TPB). Further, TPB was extended by including two more variables related to the circular economy and sustainability marketing, namely, convenience, and environmental concern. A comprehensive model is then proposed and empirically tested by collecting data from 450 consumers in the UAE. Complex statistical analyses were performed for the same purpose. It includes detailed descriptive analysis for understanding respondents’ profiles, exploratory factor analysis for extracting the underlying factors in the data, confirmatory factors analysis for the confirmation of the extracted factors and validity, and finally, full-fledged structural model testing for the proposed model fitness along with hypotheses testing. Interesting findings emerged, which will certainly contribute to helping policymakers in the Gulf and specifically the UAE, devise strategies that are not only aligned with the philosophy of the circular economy and sustainability marketing but will also ensure positive consumer behaviour. The novelty of this research is evident from the fact that in marketing these concepts are rarely researched, and to the best of the knowledge of the researchers, never attempted in the context of the Gulf region. Therefore, it will not only be a guiding research for future researchers, but also a solid foundational attempt for education, as there is a greater need to incorporate sustainability concerns in marketing education in the Gulf countries. The results of the present study can also be generalised to other Gulf countries because of the cultural similarity

A MULTISTAGE APPROACH FOR BLIND SEPARATION OF CONVOLUTIVE SPEECH MIXTURES

In this paper, we propose a novel algorithm for the separation of convolutive speech mixtures using two-microphone recordings, based on the combination of independent component analysis (ICA) and ideal binary mask (IBM), together with a post-filtering process in the cepstral domain. Essentially, the proposed algorithm consists of three steps. First, a constrained convolutive ICA algorithm is applied to separate the source signals from two-microphone recordings. In the second step, we estimate the IBM by comparing the energy of corresponding time-frequency (T-F) units from the separated sources obtained with the convolutive ICA algorithm. The last step is to reduce musical noise caused typically by T-F masking using cepstral smoothing. The performance of the proposed approach is evaluated based on both reverberant mixtures generated using a simulated room model and real recordings. The proposed algorithm offers considerably higher efficiency, together with improved speech quality while producing similar separation performance as compared with a recent approach. Index Terms — Independent component analysis (ICA), ideal binary mask (IBM), estimated binary mask, cepstral smoothing, musical noise 1

A Novel Approach for Blind Estimation of Reverberation Time using Rayleigh Distribution Model

In this paper a blind estimation approach is proposed which directly utilizes the reverberant signal for estimating the RT (Reverberation Time).For estimation a very well-known method is used; MLE (Maximum Likelihood Estimation). Distribution of the decay rate is the core of the proposed method and can be achieved from the analysis of decay curve of the energy of the sound or from enclosure impulse response. In a pre-existing state of the art method Laplace distribution is used to model reverberation decay. The method proposed in this paper make use of the Rayleigh distribution and a spotting approach for modelling decay rate and identifying region of free decay in reverberant signal respectively. Motivation for the paper was deduced from the fact, when the reverberant speech RT falls in specific range then the signals decay rate impersonate Rayleigh distribution. On the basis of results of the experiments carried out for numerous reverberant signal it is clear that the performance and accuracy of the proposed method is better than other pre-existing method

Efficient Routing Scheme for Unidirectional links in Multi-hop Networks

This paper presents an efficient routing scheme for Multi-hop Network in the presence of unidirectional links. The distinct feature of this routing scheme is the capability to actively provide routing paths even though a large number of unidirectional links are present in the network. The results depicts that the routing scheme is able to reduce the delay and routing overhead compared with the already available routing scheme like AODV and AODV-Blacklist. The performance of proposed routing scheme called Active Reverse Route (ARR) scheme is compared with AODV and AODV-Blacklist routing protocols in Multi-hop networks. The performance analysis when compared with the three routing protocols to manage unidirectional links shows that our proposed ARR scheme is superior to the AODV and AODV-Blacklist