Browsing by Author "Manamperi, WN"

Now showing 1 - 2 of 2

item: Thesis-Full-text
Enhancing the Wi-Fi Direct protocol for Vehicular Ad-hoc Networks
Manamperi, WN; Samarasinghe, T; Dias, D
We present a technique for enhancing Wi-Fi Direct (WD) for vehicular environments. Dedicated short range communication (DSRC) has been standardized for communication in Intelligent Transportation Systems (ITS). However, due to high costs at initiation, alternative communication strategies are of interest in order to facilitate the quick deployment of ITSs. WD, which is a relatively mature technology available in mobile devices, has come across as a possible alternate candidate. However, the presence of large communication delays in the WD protocol stack is a shortcoming in deploying this in highly dynamic vehicular scenarios. The objective of our work is to propose and evaluate a method to overcome some of the large transmission delays in WD. Our proposal is to use a broadcast mechanism in the downlink between the group owner (GO) and the clients of a WD group, as an alternative to the currently used peer-to-peer (P2P) method. We study our technique by simulating a bi-directional highway scenario with multiple lanes. We set up the vehicular channel model using two well-known models: Friis propagation model and the Nakagami fading model. Performance measures such as average total delay, average energy consumption of the GO, average packet loss ratio, and average packet reception ratio are presented. While the proposed GO Broadcast method reduces the downlink delay, it increases the probability of packet losses due to the lack of retransmissions. Our results demonstrate a gain in terms of average total delay and the average energy consumption of the GO. We use a theoretical analysis as well as a simulation study using OMNeT-r-K It is also shown that the degradation in performance on the downlink due to packet losses is within tolerable limits, given that the size of the group is selected properly.
item: Conference-Abstract
An Optimised stimulus for hearing screening of infants using the auditory brainstem response
Manamperi, WN; De Silva, AC
This study presents an effective stimulus which enhances the auditory brainstem responses (ABRs) from the underlying EEG. A range of different types of stimuli are implemented and tested using a modified ABR model which is a mathematical approximation of the auditory pathway that generates the ABR. The optimised stimulus is based on a chirp signal which is designed to compensate the travelling delay caused by the anatomical structure of the cochlea, especially at sound intensity levels near the hearing threshold. Results suggest an average increase of 36% in the amplitude of wave V compared to the chirp which used to design the optimised stimulus.