Computer Engineering
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Browsing Computer Engineering by Author "Eckford, Andrew W."
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Item Open Access Nonnegative Code Division Multiple Access Techniques in Molecular Communication(2017-07-27) Wang, Linchen; Eckford, Andrew W.In molecular communication, two types of multiple access have been studied: time division and molecule division. In this work, we consider code division multiple access. However, unlike code division multiple access that has been used for electromagnetic signals, we investigate optical code division multiple access: since molecular signals have the same non-negativity feature as optical signals, this scheme is a promising solution for molecular communication. In this thesis, we perform experiments and set up simulation models which match these experiments. Moreover, using simulations, we find the features of optical code division multiple access for molecular communication. Our results include an optimal information transmission scheme, and an algorithm to decode molecular information signals. Finally, we demonstrate reliable communication with multiple access by using this scheme.Item Open Access Performance Analysis of Coexistence Schemes for LTE in Unlicensed Bands(2017-07-27) Jabbariardebili, Lida; Eckford, Andrew W.LTE in the unlicensed spectrum, is becoming a popular area of research. Since LTE-Unlicensed (LTE-U) provides subscribers with higher-quality mobile voice, and video experience in high-traffic or low-signal locations, a fair coexistence mechanism with other networks, like Wi-Fi is essential. In this thesis, we propose two coexistence mechanisms that could be employed to ensure a fair channel access. First, we consider coexistence mechanism fundamentals, and then downlink system performance of two coexistence mechanisms are analyzed for multi-operator LTE-Unlicensed (LTE-U) deployments with different simulation scenarios, using NS-3. First we introduce the most trustworthy coexistence mechanism, and then a high-performance coexistence scenario is provided. We conclude that Licensed Assisted Access (LAA) can coexist with Wi-Fi without impacting Wi-Fi more than an equivalent Wi-Fi network. In the second part, uplink performance evaluation of LTE in licensed spectrum is also demonstrated.