Experimental study of multi-gigabit copper data communication over surface wave links

Abstract

With increasing data throughput requirements, copper network access over twisted pairs is reaching data rate limitations. Fibre-to-premises deployment is however much slower, costly and time consuming than previously anticipated [1]. In the following research, we are exploring the potential of using surface wave mode transmission over existing cable networks, which may allow a significant increase in data rates whilst keeping the installation time and cost low. A characterisation of surface wave transmission was carried in comparison with the widely deployed G.fast standard. Surface waves, derived by Arnold Sommerfeld, have been defined as a low attenuation, low dispersion and very wideband electromagnetic mode transmission. In order to test surface waves’ potential, a proof-of-concept experimental setup was built. The setup consisted in data generation and processing, surface wave launchers design as well as choosing the wired link (in this case DW11 cable). Several experimental transmission parameters were investigated such as the modulation, equalisation, bandwidth and carrier frequency with the aim of achieving high data throughput. Furthermore, capacity models were built to predict surface wave transmission performance in vari ous scenarios. Because of the lab dimension restrictions, a novel surface wave capacity calculation was developed to estimate data rates over an extrapolated channel response (using two length experimental responses), and obtain longer link realistic capacity estimates. Data rates of over 12 Gb/s were experimentally demonstrated on a 6.1 m DW11 surface wave link, with a BER of 2.25 ×10−5 , the signal was an OFDM modulated 64QAM transmission with 2080 MHz bandwidth and 2.1 GHz carrier frequency. In the extrapolation simulation, a DW11 surface wave link of 100 m predicted up to 14 Gb/s and at 50 m up to 35 Gb/s for high modulation and bandwidth transmission. Compared to the G.fast data rates (up to 2 Gb/s up to 50 m) [2], the results obtained tend to indicate that surface wave communications may have potential for future twisted pair access network technologies.