Distributed MIMO Radio System Architectures and Algorithms for Future High Performance IoT 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

There are now many proprietary, pseudo-open (e.g. Sigfox, LoRa, Wi-SUN) and few open standards (e.g. NB-IoT) Internet of Things (IoT) solutions. Existing solutions are predominantly based on star architectures, with minimal geographic cell overlap, or a smaller number of mesh systems.
Over-dimensioned Massive MIMO is a very promising solution for future urban mobile cellular systems, where sophisticated base station systems are hosted at a single mast location.
This research project is intended to investigate MIMO concepts applied to low data rate IoT systems, where the ‘Massive’ aspect comes instead from use of multiple, distributed and overlapping geographic cells.

The project will address a subset of the following topics:-
1) Distributed MIMO systems are scalable and have a potential to offer high availability of reliable data connectivity over a wide geographic area.
2) The over-dimensionality of MIMO is anticipated to facilitate use of low-cost, imperfect radio hardware.
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 resources offers possibilities for flexible, low cost installation.
4) Available IoT systems, so far, do not offer an acceptable balance of manufactured cost vs operational cost vs end product size, for anticipated future product concepts. An example of such a need is in healthcare monitoring and alarm systems, which often demand low-cost, high reliability yet low likelihood of use and ultra-long service life.
5) International regulatory authorities are keen to deregulate spectrum, leading to increased sharing between (often) widely different signal types - with inevitable increase in interference. For example, Ofcom supports the use of the 868MHz shared SRD band for IoT systems. There is also spectrum being proposed in the 70MHz ‘Business Radio’ band for use by IoT applications.

The research project will investigate some of the above topics and propose novel radio architectures and algorithms relevant to future IoT. Aspects of the research will therefore encompass:-
• Novel hardware system architectures, signal processing algorithms (modulation/demodulation) and Software Defined Radio concepts to use signals from multiple distributed IoT base station sites – forming a wide area distributed Massive MIMO system
• Novel Air Access MACs & PHY signals & waveforms
• Novell approaches to implementing 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.