Current and previous generations of cellular systems use orthogonal multiple access (OMA) techniques mainly to provide voice, multimedia, and data communications. For instance, frequency-division multiple access (FDMA), time-division multiple access (TDMA), code-division multiple access (CDMA), and orthogonal frequency division multiple access (OFDMA) were adopted for the 1st generation (1G), 2G, 3G, and 4G systems, respectively. The main reason behind using OMA techniques is to simplify the receiver design and the implementation of scheduling algorithms. 5G systems are expected to provide new wireless services, such as, machine-to-machine communications for connected health solutions and vehicle-to-vehicle communications as part of smart cities.
Accordingly, future cellular systems face significant challenges due to the expected tremendous increase of data rate and massive connectivity required by the new services. For instance, it is crucial to significantly improve the spectral efficiency to handle the expected 1000-fold of mobile internet data traffic increase by 2020. Additionally, due to the rapid development of the Internet of Things (IoT) for various applications, e.g., smart cities and connected health, 5G systems needs to support massive connectivity of devices with low power, low latency, and high-priority requirements. Several potential candidates have been proposed to address the challenges of 5G systems.
In this project, we focus on a novel multiple access technique, named, non-orthogonal multiple access (NOMA), which is expected to increase the spectral efficiency, accommodate massive connectivity for IoT applications including connected health, and provide low transmission latency. In NOMA, users share the same resources, e.g., time slots and frequency bands, for transmission; but there are distinguished mainly either via power-domain or code-domain multiplexing. That said, NOMA systems can accommodate much more users when compared to OMA systems that can at best support a number of users equal to or less than the number of available resources. The main obstacle in designing NOMA systems is the inter-user interference, and proper interference cancellation techniques should be used to minimize the inflicted interference effect on each user while guaranteeing the required quality of service.
Our objective in this project is to design efficient power-domain NOMA systems for wireless applications with low-power and high-priority requirements, such as connected health solutions. To properly address the high-priority requirement, we need to evaluate the impact of the residual cancellation errors resulting from the imperfect self-interference cancellation (SIC) on the performance of the connected health solutions. This can be achieved by evaluating the outage probability or the outage capacity as a function of the variance of the residual errors. To address the low-power requirement, we need to develop robust optimization techniques that jointly optimize the transmission rate and power of each node to maximize the energy-efficiency or the nodes life time, while constraining the outage probability.
Please note the student working on this project is expected to have an optimization theory and signal processing background and very good experience in one of the programming language. The student will work in an office environment and use programming language, e.g., Matlab, on a daily basis to test the developed theory.
- To hold, or expect to achieve by 15 August, an Upper Second Class Honours (2:1) Degree or equivalent from a UK institution (or overseas award deemed to be equivalent via UK NARIC) in a related or cognate field.
The University offers the following awards to support PhD study and applications are invited from UK, EU and overseas for the following levels of support:
Vice Chancellors Research Studentship (VCRS)
Full award (full-time PhD fees + DfE level of maintenance grant + RTSG for 3 years).
This scholarship will cover full-time PhD tuition fees and provide the recipient with £15,000 maintenance grant per annum for three years (subject to satisfactory academic performance). This scholarship also comes with £900 per annum for three years as a research training support grant (RTSG) allocation to help support the PhD researcher.
Vice-Chancellor’s Research Bursary (VCRB)
Part award (full-time PhD fees + 50% DfE level of maintenance grant + RTSG for 3 years).
This scholarship will cover full-time PhD tuition fees and provide the recipient with £7,500 maintenance grant per annum for three years (subject to satisfactory academic performance). This scholarship also comes with £900 per annum for three years as a research training support grant (RTSG) allocation to help support the PhD researcher.
Vice-Chancellor’s Research Fees Bursary (VCRFB)
Fees only award (PhD fees + RTSG for 3 years).
This scholarship will cover full-time PhD tuition fees for three years (subject to satisfactory academic performance). This scholarship also comes with £900 per annum for three years as a research training support grant (RTSG) allocation to help support the PhD researcher.
Department for the Economy (DFE)
The scholarship will cover tuition fees at the Home rate and a maintenance allowance of £15,285 per annum for three years. EU applicants will only be eligible for the fee’s component of the studentship (no maintenance award is provided). For Non-EU nationals the candidate must be "settled" in the UK. This scholarship also comes with £900 per annum for three years as a research training support grant (RTSG) allocation to help support the PhD researcher.
Due consideration should be given to financing your studies; for further information on cost of living etc. please refer to: www.ulster.ac.uk/doctoralcollege/postgraduate-research/fees-and-funding/financing-your-studies