research activities
Multiple Access Communications Limited (MAC Ltd) is involved in a number of research projects, which are a mixture of targeted research for our customers, externally funded research and internal research initiatives.
Our involvement in communications research is one of the key ways that MAC Ltd updates its knowledge of new technologies and innovations. The majority of our engineers have worked on research projects previously and many maintain specific research interests, including but not limited to the following areas.
Wireless broadband technologies
In the main this is customer-funded research to assess one or more of the competing 3G and evolved-3G radio access technologies, often in terms of each technology's ability to exploit a particular radio transmission or receiver architecture enhancement. We are also actively monitoring and evaluating developments of all technologies that can be used to deliver broadband services to portable, nomadic or mobile users, including DAB, DMB and DVB-H. MAC Ltd did some of the earliest work on UWB in Europe, and continues to be an authority in this field.
Network simulation and modelling
With a long history of modelling and simulating 2G and 3G system performance, MAC Ltd has teamed up with Vodafone Group Services and Nortel Networks UK as part of a DTI-funded project to examine the use of advanced computer simulations for network optimisation (see this case study or the project web site for more information).
Interference detection and monitoring
A significant proportion of MAC Ltd's work addresses the analysis and modelling of interference between the same or dissimilar radio systems. Historically MAC Ltd has been active in the field of signal measurement, including the research that led to the development of its sophisticated CatchAll receiver. More recently this work lead to the development of a low-power, low-cost radio direction finding system for detecting the source of frequency hopping radio transmissions. MAC Ltd continues to investigate new ways to detect, monitor and locate sources of interference.
Software defined radio (SDR) and cognitive radio (CR)
Starting with research on the intelligent multimode terminal, MAC Ltd has been researching and advising on SDR for over 10 years. Latterly MAC Ltd secured funding from Ofcom (as part of a consortium that included another industrial partner and three academic partners) to assess SDR as a means to improve spectral efficiency in the UK and ultimately provide a platform for the realisation of CR systems.
Ad hoc and mesh networks
MAC Ltd researched aspects of ad hoc and mesh networking as part of a DTI-funded collaborative research project (see the DTI Next Wave Technologies and Markets programme and Envisense web sites, or read a related article for more information). The work culminated in the deployment and management of an 802.11b-based ad hoc sensor network, which necessitated work on TCP/IP network stack development, implementation of a self-configuring and self-healing DSR algorithm, embedded application development and microcontroller software development.
For a separate project MAC Ltd developed a flexible software simulator that is used to assess the relative performance of conventional versus ad hoc PMR networks to derive appropriate equipment specifications for deployments in the presence of deliberate external sources of interference. We have also developed our own ad hoc network at our offices in Southampton.
Pervasive computing and software agents
Trends in computing will see intelligence move from central processing cores to multiple processing units distributed throughout the environment, with software based on agent technology making autonomous decisions to satisfy a given set of objectives. MAC Ltd is evaluating pervasive computing and software agents using simulation and its own distributed network test bed. Although software agents can be applied to many aspects of life from air-traffic control to financial markets, MAC Ltd is researching the application of agent technology to the optimisation of wireless networks.
Other
This list is by no means exhaustive. MAC Ltd maintains a diverse interest in radio communications, often working with new technologies that are not well understood, non-mainstream technologies, or unusual applications of established technologies. All this requires a more thorough understanding of the principles of radio communications than work on mainstream technologies and/or well known applications of those technologies. It was this profile of experience that lead to our early involvement in CDMA research in the early 1990s, followed by work on satellite and HAPs, and more recently work on the ATCs of mobile satellite systems.