In this executive summary of an extended commercial and technical white paper we explore, in particular the performance tradeoffs and note the growing importance of higher frequency systems, given the significant spectrum allocations and high performance in key deployment areas. We would also like to thank Prof. Michel Bousquet, of Institut Supérieur de l'Aéronautique et de l'Espace, Toulouse, and Avanti Communications  for their collaboration and support in the development of this paper. In addition to this executive summary, a detailed whitepaper is

available.