Backhaul need for speed: 60 GHz is the solution

The availability of 7–9 GHz of unlicensed spectrum at 60 GHz, advances in low-cost silicon technology, and high interference rejection due to atmospheric loss make 60 GHz an ideal solution for future 4G/5G small-cell backhaul links, where multi-gigabit rates are required. In this article, we review the 60 GHz propagation properties, the practical technology limits, and the regulatory and regional environmental impacts to present a framework for the 60 GHz backhaul link design that translates the link requirements to the essential transmitter and receiver system parameters. This approach includes a preliminary design that generates the input data set for an optimization problem. Two physical front-end architectures are discussed in this work: single-input single-output antenna for point-to-point applications and phased arrays for the future 4G/5G self-organizing backhaul networks. It is shown that selecting the proper channel bandwidth can increase the interference rejection. Furthermore, we calculate the physical data rates for the proposed modulation and coding schemes. When phased array is used, the backhaul link design can be defined as an optimization problem to find the optimum number of antennas and the gain per antenna.