Time division duplex for satellite communications

Satellite communications increasingly make use of on-board processing along with phased array technology to allow improved capacity. Conventional satellite operation uses frequency division duplex, requiring heavy duplexing filters for each of the array elements. If this could be eliminated then satellites with more beams and/or lower cost should be possible. This paper proposes a method for allowing satellites to operate time division duplex in spite of the very large round trip propagation delays