The 5G mobile communication systems introduce multiples functional splits between base station elements, new transmission bands and a large number of antennas supporting beamforming. In this scenario, a viable strategy to avoid building penetration losses is to deploy the antenna elements indoor and use a fronthaul link to establish the connection between them and the rest of the radio access network. This work explores a 5G fronthaul scheme based on analog radio over coaxial cables, leveraging this existing fixed access infrastructure to facilitate 5G deployments. Results indicate that the fronthaul solution discussed here is able to support the high capacity requirement of 5G, with the additional benefits of low transmit power, low latency and low cost. The main novelty of this paper is to investigate the potential of this kind of fronthaul architecture considering both the physical layer and economic aspects.

G.fast is a new standard from the International Telecommunication Union, which targets 1 Gb/s over short copper loops using frequencies up to 212 MHz. This new technology requires accurate parametric cable models for simulation, design, and performance evaluation tests. Some existing copper cable models were designed for the very high speed digital subscriber line spectra, i.e., frequencies up to 30 MHz, and adopt assumptions that are violated when the frequency range is extended to G.fast frequencies. This paper introduces a simple and causal cable model that is able to accurately characterize copper loops composed by single or multiple segments, in both frequency and time domains. Results using G.fast topologies show that, apart from being accurate, the new model is attractive due to its low computational cost and closed-form expressions for fitting its parameters to measurement data.

The use of a hybrid copper and fiber architecture is attractive in both fixed access and mobile backhauling scenarios. This trend led the industry and academia to start developing the fourth generation broadband system, which aims at achieving bit-rates of 1 Gb/s over short copper loops. In this context, accurate models of short twisted-pair cables operating at relatively high frequencies are key elements. This work describes new parametric cable models that incorporate four important characteristics: support of frequencies up to 200 MHz, few parameters, causal impulse responses and require relatively easy fitting procedures. The results show that the models achieve good accuracy for single segments, which are the expected topology for G.fast deployments.