Analysis and Design for Cell-Free Massive MIMO

Lead Research Organisation: Queen's University of Belfast
Department Name: Electronics Electrical Eng and Comp Sci

Abstract

Demand for wireless traffic (data traffic and the number of connected devices) has grown exponentially. With the dramatic growth of wireless devices (such as smart-phones, tablets, and laptops) and services/applications (such as real-time video calls, high-quality movies, real-time 3D games, and Internet of Things), the wireless traffic demand will continue to gain momentum. According to Cisco, global mobile data traffic will reach 43 Exabyte per month by 2021, which is about a 7-fold increase over 2016, and a 3-fold increase over 2018. By 2021, there will be 11.6 billion mobile-connected devices, which corresponds to 1.5 devices per capita. In addition, there is growing concern about green communications (low energy radiation/consumption), security and privacy. To summarize, future wireless networks have to satisfy the following requirements: (1) manage at the same time many (thousands or even millions) devices; (2) each needs a high throughput (spectral efficiency) to support many services/applications; (3) high energy efficiency; and (4) high-level security services.

Mobile network is one of the core networks in wireless communications. In conventional mobile networks, a coverage area is divided into cells. Each cell is served by one base station. We have seen many revolutions related to the cellular wireless network since its first trial was introduced in the 1970s. One of the inherent limitations of cellular networks is inter-cell interference which is the interference from other users in other cells. In particular, users at the cell boundaries perform badly due to the strong inter-cell interference which limits the performance of the whole networks. To reduce this bottleneck, network multiple-input multiple-output (MIMO) was introduced in the 2000s. In network MIMO, the base stations cooperate to serve the users. More precisely, the coverage area is divided into several disjoint clusters, each is jointly served by several base stations. Basically, network MIMO is equivalent to the cellular network with larger cell size and each cell is served by multiple base stations. There are still concepts of cells and cell boundaries, and hence, the inter-cell interference persists. In addition, network MIMO requires complicated signal co-processing with high backhaul overhead and deployment costs to reduce the effect of inter-cell interference.

In this project, we are targeting a new practical, useful, and scalable version of network MIMO called "cell-free massive MIMO". In cell-free Massive MIMO, a number of access points, which are distributed at random in a very wide area (e.g. over an entire city), serve simultaneously many users randomly distributed in the same area. There are no concepts of cells or cell boundaries. Cell-free massive MIMO reaps all benefits obtained from massive MIMO and network MIMO, and hence, it is expected to offer many advantages compared with the conventional wireless systems: 1) huge data throughput; 2) huge energy efficiency; 3) and high coverage probability. Thus, cell-free Massive MIMO is a disruptive technology for next generations of densified wireless systems. Since cell-free massive MIMO a very new research topic, a number of issues and questions still need to be tackled before rolling-out it into practice. The main objective of this project is to develop a complete, useful, and practical cell-free massive MIMO system which includes signal processing schemes, channel estimation, pilot assignment schemes, power controls, and AP selection schemes.

The application of the project results will contribute to the reduction of the ICT sector's contribution to global warming, through reduced power consumption and improved energy efficiency. It will also influence many dynamic economic sectors within the UK: telecom equipment manufacturing, telecom operators, smart cities, e-health, surveillance sector, military equipment and automotive companies.

Planned Impact

This project develops novel, low-cost, and eco-friendly solutions for future wireless systems. The project will influence broad communities and facilitate the development of vibrant businesses around the proposed technology. The following list summarises potential impacts:

1) The new knowledge will be timely for standards bodies (IEEE, ITU-IMT 2020), government agencies (Ofcom), network operators (Vodafone-UK, O2-UK), and hardware manufacturers (BAE, Thales) which are currently investing an extensive amount of resources into the research of 5G and beyond wireless systems, in order to deliver high and ubiquitous data rates to millions/billions of users. It is expected that the outcomes of the project will help these authorities to reap the theoretical benefits of deploying cell-free massive MIMO to serve the UK citizens.

2) Cell-free massive MIMO is very promising research topic and is expected to meet the demands of future wireless networks. Undoubtedly, the project has huge potential to boost research in this field, attract industrial partners, suggest ideas which will lead to research patents, and also develop solutions that will be incorporated in future communication standards. Our research outcomes will speed up the realisation of 5G and beyond networks, which are expected to enable new applications in various domains and environments ranging from entertainment to health, transport and industry, stimulating economic development in many sectors of the economy. Thus, our research results will broaden the UK competitiveness and turn the opportunities in upcoming market segments into new products and employment growth.

3) Cell-free massive MIMO can serve simultaneously thousands/millions of users in urban environments with aggregate data rates 1000x faster compared to current 4G networks. This new technology can be applied in the future networked UK society including smart cities, e-healthcare, smart vehicles, and energy management. Consequently, the results of the project will create new jobs, start-up companies, thereby creating wealth and better services for the UK population, once fully commercially exploited. In addition, the UK's ICT market is the most dynamic in the EU, characterised by a high percentage of early adopters of innovative technologies, open and transparent market, and importantly, excellent engineering skills. This project, while helps maintain the UK's research excellence, will contribute to building up the next generations of highly skilled researchers as a step towards establishing world-class research systems.

4. We recall that the overall ICT footprint has represented about 2 percent of global CO2 emissions in 2007. This percentage is predicted to increase to more than 4% in 2020, which is more than one-third of the present annual emissions of whole of United Kingdom. Furthermore, there is an increasing concern about green communications, which connect to the effects of the radiation emitted from wireless devices on the human body. Different from the conventional cellular systems where the base station sends out the information to a wide area, in cell-free massive MIMO, all access points work together to send out concentrated beams of information to the desired users at desired locations. In addition, cell-free massive MIMO can be implemented using rather simple components with low cost and footprint. As a result, cell-free massive MIMO offers huge energy efficiency with low carbon footprint. The proposed research will contribute substantially to the reduction of the ICT sector's contribution to global warming. Note that ICT is accountable for more than 10% of the UK electricity consumption. Furthermore, the radiation emitted from wireless devices on the human body will be reduced significantly.
 
Description - We have proposed a simple, efficient, and very fast algorithm to control the transmit power for cell-free massive multiple-input multiple-output (MIMO) systems. This makes cell-free massive MIMO feasible for practical implementation.
- We have developed a novel channel estimator for the cell-free massive MIMO systems. The proposed estimator is based on the machine learning technique, and can reduce the resources for channel acquisition significantly, compared to the conventional channel estimation scheme.
- We have proposed how to use cell-free massive MIMO technologies to support federated learnings.
Exploitation Route - My research outcomes have been currently published in the top IEEE journals (i.e. IEEE Transactions on Communications and IEEE Transactions on Wireless Communications) and presented in IEEE flagship conferences. These activities will be beneficial to promote our research outcomes to expert audiences (the researchers in the area of wireless communications).
- I created a blog about cell-free massive MIMO which updates all project's results and relevant research results from other researchers. This helps attracting research attention as well as disseminating knowledge to potential users (business and industry professionals)
Sectors Digital/Communication/Information Technologies (including Software),Electronics

URL https://cell-free.blogspot.com/
 
Description Cooperative-Coordinated Network Design with Fronthaul Limitation
Amount £228,416 (GBP)
Funding ID R7906ECS 
Organisation Huawei Technologies Sweden AB 
Sector Private
Country Sweden
Start 11/2021 
End 11/2023
 
Title Cell-Free Massive MIMO for Wireless Federated Learning 
Description We have designed a novel cell-free massive MIMO-based algorithm to support federated learning in a wireless environment. The proposed algorithm aims at minimising the training time of federated learning networks. This makes the use of cell-free massive MIMO for federated learning more practical, and therefore, accelerates the realisation of 6G networks. 
Type Of Material Computer model/algorithm 
Year Produced 2020 
Provided To Others? Yes  
Impact Our results demonstrate that the proposed algorithm can remarkably reduce the training time in federated learning network. Thus, this work has huge potential to boost research in machine learning and cell-free massive MIMO systems. 
URL https://ieeexplore.ieee.org/abstract/document/9124715?casa_token=1xodtihend8AAAAA:CSD6chB9dgJsCGWYp2...
 
Title Energy Efficiency Maximization in Large-Scale Cell-Free Massive MIMO: A Projected Gradient Approach 
Description In cell-free massive MIMO systems, existing solutions for this optimization problem are based on solving a sequence of second-order cone programs, whose computational complexity scales dramatically with the network size. Therefore, they are not implementable for practical large-scale cell-free massive MIMO systems. To tackle this issue, we propose an iterative power control algorithm based on the frame work of an accelerated projected gradient (APG) method. 
Type Of Material Computer model/algorithm 
Year Produced 2022 
Provided To Others? Yes  
Impact Compared with the existing approaches, our proposed method achieves the same performance, while its run time is much faster, i.e., one to two orders of magnitude reduction. Therefore, this method has a great potential to deal with large-scale optimization problems in cell-free massive MIMO, and hence, can be applied to practical scenarios. 
URL https://ieeexplore.ieee.org/document/9709200
 
Title Machine learning-based channel prediction in massive MIMO with channel aging 
Description To support the ever increasing number of devices in massive multiple-input multiple-output systems, an excessive amount of overhead is required for conventional orthogonal pilot-based channel estimation (CE) schemes. To circumvent this fundamental constraint, we design a machine learning (ML)-based time-division duplex algorithm in which channel state information (CSI) can be obtained by leveraging the temporal channel correlation. The presence of the temporal channel correlation is due to the stationarity of the propagation environment across time. The proposed ML-based predictors involve a pattern extraction implemented via a convolutional neural network (CNN), and a CSI predictor realized by an autoregressive (AR) predictor or an autoregressive network with exogenous inputs recurrent neural network (NARX-RNN). 
Type Of Material Computer model/algorithm 
Year Produced 2020 
Provided To Others? Yes  
Impact Our results demonstrate that the proposed ML-based model can remarkably improve the prediction quality for both low and high mobility scenarios, and offer great performance gains on the per-user achievable throughput. 
URL https://ieeexplore.ieee.org/abstract/document/8979256
 
Description Research collaboration with CentraleSupelec, Paris-Saclay University, France 
Organisation University of Paris-Saclay
Country France 
Sector Academic/University 
PI Contribution We have collaborated on the design of reconfigurable intelligent surface-assisted cell-free massive MIMO systems under spatially-correlated channels. With my expertise on the fundamental of the cell-free massive MIMO technology, I have contributed on the system model, performance analysis, as well as technical points related to this system.
Collaborator Contribution The research team at CentraleSupelec, Paris-Saclay University (Leading by Prof Marco Di Renzo) is very strong at reconfigurable intelligent surface technologies. They have contributed on the system modeling of intelligent surface-assisted cell-free massive MIMO systems.
Impact One top-decile IEEE journal paper (Q1): DOI 10.1109/TWC.2021.3136925
Start Year 2021
 
Description Research collaboration with SnT, University of Luxembourg, Luxembourg 
Organisation University of Luxembourg
Department Interdisciplinary Centre for Security, Reliability and Trust (SnT)
Country Luxembourg 
Sector Academic/University 
PI Contribution We have collaborated on the design of cellular/cell-free massive multiple-input multiple-output (MIMO) systems with different channel models as well as reconfigurable intelligent surface technologies. With my expertise on the fundamental of the cellular/cell-free massive MIMO technology, I have contributed on the system model, performance analysis, as well as technical points related to these systems.
Collaborator Contribution A research group at University of Luxembourg (leading by Prof Björn Ottersten) is very strong at reconfigurable intelligent surface and optimization designs. They have contributed on the application of optimization to cellular/cell-free massive multiple-input multiple-output (MIMO) systems with different channel models as well as reconfigurable intelligent surface technologies.
Impact With our collaboration, we have published 1 book chapter, 3 top decile IEEE journals (Q1), 3 top-level conference papers: 1) Book chapper: DOI 10.1049/PBTE093E_ch; 2) Journal papers: DOI 10.1109/TWC.2021.3136925; DOI 10.1109/TWC.2021.3108849; 10.1109/TVT.2021.3091020; and 3) Conference papers: DOI 10.1109/ICC42927.2021.9500981; DOI 10.1109/ICCWorkshops49005.2020.9145298
Start Year 2020
 
Description Research collaboration with a research group at Chongqing University, China 
Organisation Chongqing University
Country China 
Sector Academic/University 
PI Contribution We have proposed a novel non-coherent detection scheme in massive MIMO systems. With my expertise on massive MIMO, I have contributed on the use of massive MIMO for non-coherent detection.
Collaborator Contribution We have proposed a novel non-coherent detection scheme in massive MIMO systems. A research group at Chongqing University (leading by Dr Weiyang Xu) is very strong at signal detection, especially at non-coherent detection. They have contributed on building a novel non-coherent detection which is suitable for massive MIMO systems.
Impact A top-level conference paper: DOI 10.1109/ICC.2019.8761100
Start Year 2019
 
Description Research collaboration with a research group at Ericsson, Sweden 
Organisation Ericsson
Country Sweden 
Sector Private 
PI Contribution We have proposed a novel downlink pilot scheme for cell-free massive MIMO. My main contributions: help to derive the spectral efficiencies of cell-free massive MIMO with and without downlink pilots, and help to find the optimal power control coefficients to maximize the minimun of the spectral efficiencies..
Collaborator Contribution We have proposed a novel downlink pilot scheme for cell-free massive MIMO. The main contributions from Ericsson's side: propose the use of downlink pilots, formulate and solve an optimization power allocation problem.
Impact A top-decile IEEE journal paper (Q1): DOI 10.1109/TWC.2019.2933831
Start Year 2019
 
Description Research collaboration with a research group at Hanoi University of Science & Technology, Vietnam 
Organisation Hanoi University of Science and Technology
Country Viet Nam 
Sector Academic/University 
PI Contribution We have collaborated on the nove design of massive multiple-input multiple-output (MIMO) systems including pilot assignment and power control algorithms. With my expertise on the fundamental of the massive MIMO technology, I have contributed on the system model, performance analysis, as well as technical points related to this system.
Collaborator Contribution The research team at Hanoi University of Science & Technology (Leading by Tien Hoa Nguyen) is very strong at pilot designs for wireless communication systems. They proposed a novel pilot assignment for joint uplink-downlink spectral efficiency enhancement in massive MIMO systems with spatial correlation.
Impact One top-decile IEEE journal paper (Q1): DOI 10.1109/TVT.2021.3091020
Start Year 2021
 
Description Research collaboration with a research group at Linkoping University, Sweden 
Organisation Linkoping University
Country Sweden 
Sector Academic/University 
PI Contribution We have jointly written a journal which investigates the enormous potential of cell-free massive MIMO while addressing practical deployment issues to deal with the increased back/front-hauling overhead deriving from the signal co-processing. My main contributions: discussing the technical points of the paper, and writing the power allocation and pilot assignment parts.
Collaborator Contribution We have jointly written a journal which investigates the enormous potential of cell-free massive MIMO while addressing practical deployment issues to deal with the increased back/front-hauling overhead deriving from the signal co-processing. A research group at Linkoping University (leading by Prof Erik G. Larsson) is very strong at practical deployment issues. They have contributed on the practical aspects including radio stripe systems, front-haul and back-haul capacity, and network synchronization
Impact With our collaboration, we have published 4 top decile IEEE journals (Q1), 2 top-level conference papers: 1) 4 IEEE Journal papers: (DOI) 10.1109/TCOMM.2021.3055522; (DOI) 10.1109/TCOMM.2020.3028305; (DOI) 10.1109/TGCN.2019.2932071; and (DOI) 10.1109/TWC.2019.2933831; 2) 1 EURASIP journal paper: (DOI) 10.1186/s13638-019-1507-0; and 3) IEEE conference papers: (DOI) 10.1109/GLOBECOM46510.2021.9685968; and (DOI) 10.1109/ICC.2019.8761134
Start Year 2019
 
Description Research collaboration with a research group at Pompeu Fabra University, Spain 
Organisation Pompeu Fabra University
Country Spain 
Sector Academic/University 
PI Contribution We have proposed a solution to the channel estimation and hybrid combining problems in wideband THz massive MIMO. With my expertise on massive MIMO, my research team has contributed on a feasible design of massive MIMO in THz commications.
Collaborator Contribution A research group at Pompeu Fabra University (leading by Dr Weiyang Xu) is strong at THz communications. They have contributed on THz channel model with spatial-frequency wideband effects, and proposing compressive sensing algorithm along with a wideband dictionary to acquire reliably the channel state information with reduced training overhead under the spatial-wideband effect.
Impact One top-decile IEEE journal paper (Q1): accepted One top-level conference paper: DOI 10.1109/ICC40277.2020.9148706
Start Year 2020
 
Description Research collaboration with a research group at University College Dublin, Ireland 
Organisation University College Dublin
Country Ireland 
Sector Academic/University 
PI Contribution We have proposed a novel, low cost and scalable power control algorithm for cell-free massive MIMO systems. My research team has contributed on building a specific cell-free massive MIMO system including a completed transmission protocol.
Collaborator Contribution The research team at University College Dublin (Leading by Dr Le-Nam Tran) is very strong at optimzation designs. They proposed a novel and scalable technique to control the powers transmitted from the access points and the users in the cell-free massive MIMO systems.
Impact One top-level conference paper:DOI: 10.1109/PIMRC48278.2020.9217298 One top-decile IEEE journal paper (Q1) is submitted. Link: https://arxiv.org/pdf/2009.07167.pdf
Start Year 2019
 
Description Research collaboration with a research group at University of Saskatchewan, Canada 
Organisation University of Saskatchewan
Country Canada 
Sector Academic/University 
PI Contribution We have proposed a novel pilot design to improve the performance of multicarrier massive MIMO systems. My research team has contributed on building a specific massive MIMO system and some corresponding fundamental aspects.
Collaborator Contribution The research team at University of Saskatchewan (Leading by Prof Ha H. Nguyen) is strong at multicarrier systems. They proposed a novel pilot design for massive MIMO system to reduce the channel estimation overhead, and hence, increase the spectral efficiency.
Impact One top-level IEEE journal: DOI: 10.1109/LWC.2022.3155610
Start Year 2021
 
Description Research collaboration with a research group at University of Technology Sydney, Australia 
Organisation University of Technology Sydney
Country Australia 
Sector Academic/University 
PI Contribution We have collaborated on the design of cell-free massive multiple-input multiple-output (MIMO) in the short blocklength regime. The design is applied for ultra-reliable low-latency communications (URLLCs). With my expertise on the cell-free massive MIMO technology, I have contributed on the system model, performance analysis, as well as technical points related to this system.
Collaborator Contribution The research team at University of Technology, Sydney (Leading by Prof Tuan D. Hoang) is very strong at optimzation as well as short blocklength designs. They proposed a novel power control algorithm to optimize the performance of cell-free massive MIMO in the short blocklength regime.
Impact One top-decile IEEE journal paper (Q1): DOI 10.1109/TWC.2021.3070836
Start Year 2021
 
Description Research collaboration with a research group at the McGill University, Canada 
Organisation McGill University
Country Canada 
Sector Academic/University 
PI Contribution We proposed a novel cell-free massive MIMO system with full-duplex mode. I have contributed on the cell-free massive aspect.
Collaborator Contribution We proposed a novel cell-free massive MIMO system with full-duplex mode. Prof Tho Le-Ngoc at McGill University is an expert on full-duplex systems. He has proposed to use full-duplex mode for cell-free massive MIMO.
Impact A top-level conference paper: DOI 10.1109/ICC.2019.8761711
Start Year 2019
 
Description Research collaboration with a research group at the University Of Surrey, UK 
Organisation University of Surrey
Country United Kingdom 
Sector Academic/University 
PI Contribution We have worked on the energy efficiency aspect of cell-free massive MIMO systems. My main contributions: derive the energy efficiency of a cell-free massive MIMO system, and discuss technical points related to cell-free massive MIMO with the collaborators.
Collaborator Contribution We have worked on the energy efficiency aspect of cell-free massive MIMO systems. A research group at the University Of Surrey (leading by Prof Pei Xiao) is very strong at optimization theory. They have contributed on proposing and solving a power allocation problem which maximizes the system energy efficiency.
Impact A top IEEE journal paper (Q1): DOI: 10.1109/TGCN.2019.2932071 A top-level conference paper: DOI: 10.1109/ICC.2019.8761134
Start Year 2019
 
Description Research collaboration with a research group at the University of Newcastle, Australia 
Organisation University of Newcastle
Country Australia 
Sector Academic/University 
PI Contribution We have proposed a novel transmission protocol of cell-free massive MIMO to support federated learning networks. My team have contributed on the designs of transmission protocol and signal processing for cell-free massive MIMO systems.
Collaborator Contribution The research group at the University of Newcastle (leading by Dr Duy Ngo) is very strong at optimization and machine learning. They have contributed on the federated learning design and resource allocations.
Impact With our collaboration, we have published 1 top decile IEEE journals (Q1), 2 top-level conference papers: 1) 1 top-decile IEEE journal paper (Q1): (DOI)10.1109/TWC.2020.3002988; and 2) 2 Conference papers: (DOI)10.1109/GLOBECOM46510.2021.9685968; and (DOI)10.1109/ICC42927.2021.9500541
Start Year 2020
 
Description Research collaboration with a research group at the University of Southampton, UK 
Organisation University of Southampton
Country United Kingdom 
Sector Academic/University 
PI Contribution We worked on the application of non-orthogonal multiple access (NOMA) technique to cell-free massive MIMO systems. My main contributions: help to derive the spectral efficiency of cell-free massive MIMO with NOMA, and help to solve the an optimal power control problem which maximizes the minimum BE of a user under per-access point power constraints.
Collaborator Contribution We worked on the application of non-orthogonal multiple access (NOMA) technique to cell-free massive MIMO systems. Prof Lajos Hanzo (University of Southampton, UK) is an expert on NOMA. He has contributed on the method to use NOMA technology for cell-free massive MIMO.
Impact A top IEEE journal paper (Q1): DOI 10.1109/TCOMM.2019.2952574 A top-level conference paper: DOI 10.1109/ICC.2019.8761134
Start Year 2019
 
Description Research collaboration with a research group at the University of York, UK 
Organisation University of York
Country United Kingdom 
Sector Academic/University 
PI Contribution We have collaborated on the design of cell-free massive multiple-input multiple-output (MIMO) systems under limited back-hauls. With my expertise on the fundamental of the cell-free massive MIMO technology, I have contributed on the system model, performance analysis, as well as technical points related to this system.
Collaborator Contribution We have collaborated on the design of cell-free massive multiple-input multiple-output (MIMO) systems under limited back-hauls. A research group at the University of York (leading by Prof Alister Burr) is very strong at quantization theory. They have contributed on the application of quantization theory to cell-free massive MIMO systems when the limited back-hauls are taken into account.
Impact With our collaboration, we have published 2 top decile IEEE journals (Q1), 3 top-level conference papers: 1) Journal papers: DOI 10.1109/TGCN.2019.2932071 10.1109/TCOMM.2019.2952574 2) Conference papers: DOI: 10.1109/ICC.2019.8761134 10.1109/ICC.2019.8761072 10.1109/TCOMM.2019.2926706
Start Year 2019
 
Description (Online) Invited Talk, Huawei Stockholm, Sweden 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Industry/Business
Results and Impact The talk is about the novel cell-free massive MIMO technology (my UKRI FLF research direction) which I am developing. The purpose of this talk is to attract the research interest from big telecom companies like Huawei, and to establish a strong research collaboration with industry. This will help to translate the scientific results into practical benefits.
Output: a research collaboration project (between my team and Huawei-Sweden) was discussed and is being finalized.
Year(s) Of Engagement Activity 2020
 
Description (Online) Tutorial at the IEEE International Conference on Communications and Electronics (ICCE) 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Postgraduate students
Results and Impact I gave a tutorial on cellular/cell-free massive MIMO systems at the IEEE International Conference on Communications and Electronics (ICCE), Jan 13, 2021. About 30 researchers attended the tutorial. The main purpose of the tutorial is to provide comprehensive overview of state-of-the-art research on cellular/cell-free massive MIMO. Fundamental aspects of these systems will be discussed in detail. The discussion will serve as a good roadmap for start-up and consequently motivates researchers from both industry and academia to work in this area. There were a lot of research interest of the tutorial. Many research questions were discussed after the tutorial.
Year(s) Of Engagement Activity 2021
URL https://www.ieee-icce.org/p/tutorials
 
Description Asilomar conference special session chair 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact I co-organised a special session on "Massive MIMO: Cell-Free and Beyond" at the Asilomar Conference on Signals, Systems, and Computers, Nov 2020. The goal of the special session is to solicit the recent developments of cell-free massive MIMO technologies for beyond-5G networks. This special brought together academic and industrial researchers to identify and discuss potential use cases, open research problems, technical challenges, and solution methods in this context.
Year(s) Of Engagement Activity 2020
 
Description Cell-Free Massive MIMO Blog 
Form Of Engagement Activity Engagement focused website, blog or social media channel
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Policymakers/politicians
Results and Impact I have created a blog about cell-free massive MIMO which updates the project's results and relevant research results from other researchers. The blog has received the interest from researchers in both academia and industry working on cell-free massive MIMO. This enables us to disseminate knowledge to potential users.
Year(s) Of Engagement Activity 2019,2020
URL https://cell-free.blogspot.com/
 
Description ICC Workshop chair 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact I co-organised a workshop at the IEEE International Conference on Communications (ICC) which is a flagship conference in the field of communications. The workshop is a full-day workshop on "Scalable Massive MIMO Technologies for beyond 5G". The goal of the workshop is to solicit the recent developments of massive MIMO technologies with a vision of their potential evolvement into beyond 5G and towards 6G. This workshop brought together academic and industrial researchers to identify and discuss potential use cases, open research problems, technical challenges, and solution methods in this context. This workshop has received a lot of research interest with more than 40 high-quality paper submissions, and 16 best papers are selected to present.
Year(s) Of Engagement Activity 2020
URL https://icc2020.ieee-icc.org/workshop/ws-13-workshop-on-scalable-massive-mimo-technologies-beyond-5g
 
Description Interview for IEEE Signal Processing Magazine 
Form Of Engagement Activity A magazine, newsletter or online publication
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact I was interviewed about my current work related to this project by a writer of IEEE Signal Processing magazine. After the interview, an article is published. This helps to attract the research interest in cell-free massive MIMO (which is my project topic).
Year(s) Of Engagement Activity 2020
URL https://ieeexplore.ieee.org/document/8962363
 
Description Invited Talk at the Asilomar Conference, USA 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact The Asilomar Conference on Signals, Systems, and Computers is a yearly Conference held on the Asilomar Grounds in Pacific Grove, CA, USA. The IEEE Signal Processing Society is a technical co-sponsor. It provides a forum for presenting recent and novel work in various areas of theoretical and applied signal processing.

I was invited to give a talk about "First-Order Methods for Power Control in Cell-Free Massive MIMO". The novel first order method for power control in my talk has received a lot of research interest from both academia and industry.
Year(s) Of Engagement Activity 2019
URL https://signalprocessingsociety.org/blog/acssc-2019-2019-asilomar-conference-signals-systems-and-com...
 
Description Invited Talk at the Toshiba Research Europe Limited, Bristol, UK 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach Regional
Primary Audience Industry/Business
Results and Impact Visit the Toshiba Research Europe Limited, Bristol, UK and give a talk about "Cell-Free Massive MIMO: Key Technology for the Future Wireless Systems". Host is Dr. Woon Hau Chin. The purpose of this talk is to introduce my project topic which is very new as well as to attract the research interest from industry. After the talk, I have received good feedback and interest from the audiences.
Year(s) Of Engagement Activity 2019
 
Description Invited Talk at the University of Bristol, UK 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach Regional
Primary Audience Professional Practitioners
Results and Impact Visit the University of Bristol, Bristol, UK, and give a talk about "Cell-Free Massive MIMO: Key Technology for the Future Wireless Systems". Host is Prof. Mark Beach. The purpose of this talk is to introduce my project topic which is very new. After the talk, I have received good feedback and interest from the audiences.
Year(s) Of Engagement Activity 2019
 
Description Keynote Speaker at Radio Access Network Techniques for 6G, supported by DCMS and UK SPF 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Professional Practitioners
Results and Impact The UK Spectrum Policy Forum (SPF) and DCMS are supporting a series of University-run workshops to showcase the current research projects having the best potential to address 6G wireless research priorities. Bristol, Surrey and Strathclyde have been selected to run the workshops but the intention is for these workshops to be a platform for all UK universities having relevant wireless research. Each hosting University has been entrusted by the SPF and DCMS to identify outstanding research projects from other Universities to showcase at their workshops. The output from this series of workshops will be a White Paper for the UK SPF to present to government that validates the research projects as relevant to UK 6G research priorities, identifies gaps, suggests opportunities for collaboration, looks at the adequacy of research funding streams and flag potential implications for 6G spectrum policy.
Year(s) Of Engagement Activity 2021
URL https://www.techuk.org/what-we-deliver/events/radio-access-network-techniques-for-6g.html
 
Description Keynote Speaker at the Millimeter Wave Symposium, Belfast, UK 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact The mm-Wave symposium was held on 18th October 2019 in the Great Hall of Queen's University Belfast. It focused on wireless communications for densely populated environments, a big challenge for future 5G networks (millimetre wave). In this symposium, we had a number of talks from academic and industry experts from the USA, Sweden, Ireland, Scotland and England about how 5G will provide densely populated places with unprecedented wireless connectivity.This balance worked well as it is always extremely valuable to learn the thoughts of industry and our stakeholders so that research remains informed.
Year(s) Of Engagement Activity 2019
URL https://www.qub.ac.uk/ecit/News/TheCentreforWirelessInnovationhost4thmm-Wavesymposium.html
 
Description Special session chair, IEEE International Conference on Communications and Electronics 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Postgraduate students
Results and Impact I co-organised a special session "Special Session on MIMO Technologies for Beyond 5G and Towards 6G" at the IEEE International Conference on Communications and Electronics, January 2021. The goal of the special session is to solicit the recent developments of MIMO technologies with a vision of their potential evolvement into beyond 5G and towards 6G. This special session brought together academic and industrial researchers to identify and discuss potential use cases, open research problems, technical challenges, and solution methods in this context. This workshop has received a lot of research interest.
Year(s) Of Engagement Activity 2021,2022
 
Description Talk at SPAWC, France 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact Present two research works "Massive MIMO AF Relaying with Channel Estimation and Power Control Techniques" and "Machine Learning-Based Channel Estimation in Massive MIMO with Channel Aging" at the IEEE International Workshop on Signal Processing Advances in Wireless Communications (SPAWC), France 2019. Both works are about the designs of massive MIMO systems. After the talk, our work has received more research interest from the signal processing society.
Year(s) Of Engagement Activity 2019
URL http://www.spawc2019.org/program/tech_prog/
 
Description Tutorial at the 30th Biennial Symposium on Communications (BSC) 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Postgraduate students
Results and Impact I gave a tutorial on "Massive MIMO: From Cellular to Cell-Free Networks" at the 30th Biennial Symposium on Communications (BSC), Canada, June, 2021. About 50 researchers attended the tutorial. The main purpose of the tutorial is to provide comprehensive overview of state-of-the-art research on cellular/cell-free massive MIMO. Fundamental aspects of these systems will be discussed in detail. The discussion will serve as a good roadmap for start-up and consequently motivates researchers from both industry and academia to work in this area. There were a lot of research interest of the tutorial. Many research questions were discussed after the tutorial.
Year(s) Of Engagement Activity 2021
URL http://infotheory.ca/bsc2021/Tutorials.html