Contribution to the Rapid Acquisition of Signals for UWB Communication Systems

Ultra Wide-band is a promising technology for future short-range wireless communications with high data rate. In generally, one of the biggest difficult tasks for researchers today is the acquisition task of signals, where they are looking through different tools for getting a good quality of transmission; the phenomenon of multipath always stands up in the front as the first problem to be faced. When we talk about the Ultra Wide Band (UWB) signals, the problem becomes more complicated due to ultrashort impulses duration used by this kind of signals that causes the generation of paths by huge numbers. In this thesis, to address the task mentioned above, the study is subdivided into two aspects. The first one is the UWB channel estimation that we have done to have information about the amplitudes and the delays of the paths. For this purpose, a maximum likelihood method is used to find the amplitudes and the delays estimate using two estimation contexts: Data Aided (DA) and Non-Data-Aided (NDA). In the second aspect, various parameters affecting the acquisition of signals are evaluated. Furthermore, several contributions in the framework of a new strategy based on an Intelligent Controlling System (ICS) are done and detailed in this thesis for the first once. This system is characterised by its flexibility through two techniques, one that allows to users to communicate even with different M-ary PPM levels at the same time. Another technique that gives the flexibility for dealing with the phenomenon of multipath, where this latter is combated through manipulating the modulation’s levels via the ICS to achieve a rapid acquisition of UWB signals

Lameness detection in sheep via multi-data analysis of a wearable sensor

Lameness is one of the significant concerns in the sheep industry in the UK. The prior detection of the lame sheep will be expected to decrease the prevalence of lameness, eliminate the annual loss of the individual sheep, and increase the overall farm productivity. The movement measurements for an individual sheep was retrieved from a mounted sensor on its neck. The sensor readings will be analysed according to data mining algorithms to predict lameness in its early stage. This study aims to build an automatic model to enable the shepherd to react quickly to the better treatment for the lame sheep

Towards 5G wireless systems: A modified Rake receiver for UWB indoor multipath channels

This paper presents a modified receiver based on the conventional Rake receiver for Ultra-Wide Band (UWB) indoor channels of femtocell systems and aims to propose a new solution to mitigate the multipath phenomenon. Furthermore, this work proposes an upgrade for the conventional Rake receiver to fulfill the needs of 5G wireless systems through a new concept named “hybrid femtocell” that joins UWB with millimeter wave (mmWave) signals. The modified receiver is considered to be a part of the UWB/mmWave hybrid femtocell system, where it is developed for confronting the indoor multipath channels and to ensure a flexible transmission based on an Intelligent Controlling System (ICS). Hence, we seek to exploit the circumstances when the channel is less complex to switch the transmission to a higher data rate through higher M-ary Pulse Position Modulation (PPM). Furthermore, an ICS algorithm is proposed and an analytical model is developed followed by performance studies through simulation results. The results show that using the UWB technology through the modified receiver in femtocells could aid in mitigating the multipath effects and ensuring high throughputs. Thus, the UWB based system promotes Internet of Things (IoT) devices in indoor multipath channels of future 5G

Evaluation of multi-user effects on the channel in the TH-UWB communication systems

This paper investigates the UWB channel to focus the light on the multi-user and their impact on the UWB communication performance. We addressed the performance evaluation of Time Hopping Ultra-Wideband (TH-UWB) system with the Pulse Position Modulation (PPM) by assuming multiuser scenarios. The channel used here is the IEEE 802.15.3a that consists of Channel Models (CM1~CM4). Moreover, a Rake receiver is adopted to collect the multipath occurring in the UWB channel. Thus, the reception of signals requires a channel estimation stage (for amplitudes and delays) which is achieved here using the Maximum-Likelihood (ML) approach with two contexts i.e. Data Added (DA) and Non-Data Added (NDA). Simulation results confirm that the channel estimation is affected slightly by the multi-user in terms of amplitudes and considerably in terms of delays, and thus leads to focus much on multipath time resolution to gain better UWB communication accuracy and BER performance

Novel detection algorithm of speech activity and the impact of speech codecs on remote speaker recognition system

International audienceIn this paper, we studied the effects of voice codecs on remote speaker recognition system, considering three types of speech codec: PCM, DPCM and ADPCM conforming to International Telecommunications Union - Telecoms (ITU-T) recommendation used in telephony and VoIP (Voice over Internet Protocol). To improve the performance of speaker recognition in a noisy environment, we propose a new speech activity detection algorithm (SAD) using "Adaptive Threshold", which can be simulated with speech wave files of TIMIT (Texas Instruments Massachusetts Institute of Technology) database that allows recognition system to be done under almost ideal conditions. Moreover, the speaker recognition system is based on Vector Quantization as speaker modeling technique and Mel Frequency Cepstral Coefficient (MFCC) as feature extraction technique. Where, the feature extraction proceed after (for testing phase) and before (for training phase) the speech is sending over communication channel. Therefore, the digital channels can introduce several types of degradation. To overcome the channel degradation, a convolutional code is used as error-control coding with AWGN channel. Finely, In our simulation with Matlab we have used 30 speakers of different regions (10 male and 20female), the best overall performance of speech codecs was observed for the PCM code in terms of recognition rate accuracy and runtim

The use of multivariable sensor data to early detect lameness in sheep

Lameness is a clinical symptom referring to locomotion changes that widely differ from normal gait or posture [1]. Lameness has a negative impact on both farm productivity and sheep welfare. The annual loss to the British sheep industry, because of the footrot only ;which is one of the common lameness causes, is estimated by £10 for each ewe[2]. Since lameness is often an infectious disease that can be easily spread¬ within the flock, the prior detection of the lame sheep will be expected to decrease the prevalence of lameness and enabling the shepherd to react quickly to the better treatment. The prototype sensor has been developed primarily to conduct this research, offering an automatic monitoring of individual sheep to collect behavioural data measurements from a precise sensor that mounted within a neck collar. The sensor variables include 3-axis acceleration, 3-axis Gyroscope, (Roll, Pitch, Heading) angles, longitude, latitude and time. The sensor parameters were be used as inputs to data analysis algorithms. The preliminary results from applying pre-existing classification algorithms gave a positive indication for earlier lameness detection, however; the next experiments aim to simplify the process of lameness detection by eliminating the least effective parameters. [1] Van Nuffel, A., Zwertvaegher, I., Pluym, L., et al., 2015. Lameness Detection in Dairy Cows: Part 1. How to Distinguish between Non-Lame and Lame Cows Based on Differences in Locomotion or Behavior. Animals, 5(3), pp.838–860. Available at: http://www.mdpi.com/2076-2615/5/3/0387/. [2] AHDB Beef & Lamb, Agriculture & Horticulture Development Board. 2016. Manual 7 - Reducing lameness for better returns. [ONLINE] Available at: http://beefandlamb.ahdb.org.uk/returns/health-and-fertility/. [Accessed 25 October 16]