Cooperative backhaul aided next-generation digital subscriber loops

Cisco has recently released its traffic forecast study, which suggests that the world will enter into the Zetta-byte era in 2018. The UK alone generates and consumes approximately 10% of the entire global tele-traffic, making the UK one of the most data-dependent countries on the globe. To meet the demand of exponentially growing tele-traffic and to sustain the current level of economical growth, a high-quality digital infrastructure based on innovative and cost efficient solutions is required. The current geo-economics and building-preservation of historic cities do not favour the pervasive penetration of fibre. Hence, a lower-cost solution based on the improved exploitation of the existing copper network is essential to facilitate transformation of the digital infrastructure to support the next evolutionary step to Giga-bit/s data rates.

Since their emergence in the 80's, Digital Subscriber Lines (DSL) have remained the dominant technology for broadband access with 364.1 million subscribers worldwide. Eventually fibre solutions will become ubiquitous, but given the vast copper network across the UK/EU, the pervasive penetration of fibre may be delayed for decades and copper may remain the best solution for heritage environments to prevent irreparable damage to historical street fabric. Owing to significant technology investments, DSL technology has evolved dramatically, increasing the throughput from Kilo-bit/s upto Giga-bit/s, with the aid of the newly developed G.fast solution.

However, experts from our industrial partner BT believe that the throughput achieved with the aid of the state-of-the-art copper technology may only represent less than 30% of its ultimate capacity, when we exploit the hitherto unexploited high-frequency band. Hence, the research of next-generation ultra-high-throughput DSL systems beyond G.fast becomes of crucial importance and timely, where radically new signal processing techniques have to be conceived. The challenge is to conquer the entire Very High Frequency (VHF) band and to holistically design the amalgamated wire-line and wireless system considered. Our proposed research starts from the fundamental understanding of the DSL channel over the entire 500 MHz VHF band to the design of radical signal processing techniques for tackling the critical challenges. Holistic system optimization is proposed for exploiting the full potential of copper. Thanks to BT's huge support, our proposed research has a high immediate engineering impact and a long-term scientific adventure.

o Economic/Societal Impact - The digital infrastructure plays a major role in spreading scientific, educational business and social information globally. However, the UK's growth in digital infrastructure lags behind that of its competitors, where the City Growth Commission report underlines that the existing national infrastructure is not matching the needs of sustained growth and if no investments are made to circumvent this problem, a loss of £90 billion will be encountered by 2026. The report further suggests that for every £1 invested, the UK's GDP is boosted by £1.3. Owing to the expensive roll-out of a full fibre infrastructure, a novel copper technology achieving tens of Giga bits/s throughput will be required to generate significant revenue for meeting the tele-traffic demands in a cost-effective and sustainable way. Hence, the success of this proposal is vital and lies within the primary focus of the UK's economy.

o Personal Impact - The research would make a substantial impact on the wider research community. This would help the UK to play a leading role in these transformative research areas. It would also help both the University of Southampton and Newcastle University to maintain its world-class research reputation, as well as further developing the expertise and project leadership skills of the investigators. The experience obtained under this EPSRC project would enable us to undertake more ambitious projects in the future, for the sake of making an even wider impact and contributions.

o Academic Impact - The research would make a substantial impact on the wider research community, as detailed in the Academic Beneficiaries section.

The underlying scientific approach will shed light on radical advances in `digital signal processing' in support of `an intelligent information infrastructure', under the EPSRC priority `Information and Communication Technologies'. Moreover, our proposed research on ultra-high-throughput DSL systems will conceive the required high-capacity back-haul of small-cells in the 5G wireless networks, which is addressed under the growing EPSRC `RF and microwave communications' research area. Finally, the wire-line and wireless convergence facilitated by our proposed research provides the fundamental support for creating the next generation Internet, which is envisioned to provide £50 ~ £100 billion per year benefits for the UK according to the `UK Future Internet Strategy Group'. Hence, our proposed research will establish such a digital infrastructure for supporting `information technology as a utility', as envisioned by the `Digital Economy' theme.