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.