Distributed MIMO Radio System Architectures and Algorithms for Future Mobile Communications

Applications are invited for a 3 year Ph.D. studentship on the theme described below, as part of The University of Sheffield’s Communications Research Group and the Advanced Radio Technology Centre.

Details

Over-dimensioned Massive MIMO is one of the most promising solutions for meeting the data rate, delay and energy efficiency of future cellular systems. Most of the theoretical and experimental research towards Massive MIMO, however, has been carried out under the assumption of an urban environment with relatively small cells and high user densities where sophisticated base station systems can be hosted at a single mast location.
This project will address a subset of the following topics:-
1) Many rural and impoverished communities around the world are lagging behind in data connectivity, due to infrastructure deployment cost and subsequent operational cost. This is negatively impacting social inclusion and mobility as well as commercial development opportunities in such communities. Distributed MIMO systems are scalable and have a potential to offer high speed services to remote areas at a relatively low cost. However, the robustness of massive MIMO in the case of distributed transceivers is yet to be demonstrated.
2) Massive MIMO is tolerant against imperfect hardware components in the radio system signal chain (e.g. noise and non-linearity), at least in the large antenna limit. Hence the use of Massive MIMO may simplify the performance requirements for future RF systems. It is not, however, entirely clear how robust massive MIMO systems are in the non-asymptotic region whilst using cost effective components.
3) Use of ‘Cloud’ based computational resource for both signal processing (modulation/demodulation) and algorithmic processing (MAC and Network) is growing in relevance. Using such distributed computational resources offers a further possibility for a flexible low cost alternative to massive MIMO in areas where centralised base station would be too costly to deploy.
4) International regulatory authorities are keen to deregulate spectrum, leading to increased sharing between (often) widely different signal types - with inevitable increase in interference.

The research project will investigate some of the above topics and propose novel radio architectures and algorithms relevant to cellular communications Massive MIMO. Aspects of the research will therefore include:-
• Novel hardware system architectures, signal processing algorithms (modulation/demodulation) and Software Defined Radio concepts to use signals from multiple distributed base station sites – forming a wide area distributed Massive MIMO system.
• Novel Air Access MACs & PHY signals & waveforms
• Novell approaches to implement signal synchronisation in wide area distributed MIMO sites (symbol level and upwards)
• Distributed MIMO radio backhaul network topologies
• Cognitive Radio systems that intelligently assess and utilise shared spectrum
It is expected that the project will incorporate theoretical, software and hardware research. Hence, researchers can expect to become involved in designing, implementing and testing proposals in lab and field environments.