chris horn's blog

In the 70s I was a postgraduate student at TCD Computer Science, and interested in digital satellite networking and local area networking technologies. I spent some time studying the design of the Cambridge Ring and other token ring networks. I was then completely inspired by the emergence of CSMSA/CD Ethernet algorithm (in turn derived from the earlier ALOHAnet radio broadcast network) whereby instead of carefully synchronized access to the shared medium, senders are optimistically allowed to transmit whenever they wish: if interference occurs on the medium because of simultaneous transmission, then a randomized backoff procedure allows the system to recover.

I was reminded of all this when I was chatting last week to Lawrence Cowsar, head of Bell Labs Ireland and CTO of the CTVR initiative (I'm chair at CTVR). Sometimes interesting systems result from relaxing constraints and encouraging established taboos to be challenged: for Ethernet, the taboo of careful synchronized access was replaced by unconstrained transmission initiation.

Lawrence, over dinner, was bemoaning the fact that academic research funding is usually and inevitably given for highly focused, highly specialist, uni-disciplinary research. As a result, although the majority of postgraduate researchers, PhDs and post-doctorates may have some experience in team work, that team work is only within the constraints of their own particular research area, under the guidance in most cases of an appropriately myopic faculty member.

By contrast, in general in industry, and in Bell Labs as one example, researchers pro-actively participate in inter-disciplinary teams. This in general seems to be in complete contrast to most academic research. One reason this seems to be is that in general it is difficult to find funding agencies willing to invest in real inter-disciplinary projects, for which multiple research laboratories and multiple terminologies and backgrounds are involved – in general proposals for such research are peer reviewed by research specialists who in turn emphasize uni-disciplinary and singular focus as the best way that their own particular state of the art can be advanced.

I was also reminded of the inertia towards “interference” of disciplines and research when chatting to Lawrence about the technology and algorithms of co-channel management for mobile phone (cellular phone, if you are US) networks. In today’s mobile networks, transmitter masts are carefully erected across a city or landscape so as to minimize interference between masts which reuse the same radio frequencies. This co-channel management challenge is usually resolved by map-colouring algorithms, which allocate frequencies to masts during the network design so as to minimize interference. Sometimes, I smiled to myself, do research proposers seeking financial support from various funding agencies use a map colouring algorithm to minimize the overlaps between their work and so optimize their chances of funding ?

CTVR, and the other CSETs funded by SFI, really are inter-disciplinary: multiple laboratories, academic and industrial, with a very large set of skills and backgrounds. Terminology and a common ability to communicate and collaborate were definitely a problem in the early stage of CTVR. However, we are now seeing highly interesting results which IMHO could only have emerged specifically because of the inter-disciplinary nature of CTVR.

One example is collaboration between the thermal (heat) management research team in the University of Limerick, the radio frequency (RF) and dynamic spectrum research team in NUI Maynooth, the software radio team in TCD, and finally the constraint and optimization analysts at UCC (a full list of CTVR partners is here). It turns out that the taboo of pair-wise interference minimization for co-channel algorithms for mobile (cellular) phone networks can be broken. In fact, channels need not be carefully separated, and interference can be allowed. Using insights from “temperature interference” in thermal management systems, instead of pair-wise constraints between transmitters, a single constraint can be applied to all transmitters whose signals can still be reliably discerned by a receiver. Channels can then be allocated in mobile networks in such a way that has the commercial benefit of reducing the numbers of transmission masts and equipment required.

Who would have thought that research into heat management would lead to an interesting new way of allocating channel frequencies in a mobile phone network ?

Another example of multi-disciplinary work is the application of well understood results in the radio frequency and dynamic spectrum field to the relatively younger area of photonics and management of light, for next generation 100Gigabit Ethernet – work being led by Tyndall at UCC, but for which the NUI Maynooth RF engineers have been able to bring remarkable insight.

In my view – and I believe I speak for Lawrence too – some of the ablest and best researchers which industry can hire come from those postgraduates and post-doctorates who have truly experienced and innovated in inter-disciplinary research. Taboos can sometimes be best challenged and overcome by researchers from outside the immediate specialist domain in question. And yet, world-wide, much academic research seems structurally resistant to such ways of working.