System and method for maintaining spectral capacity in time division duplex (TDD) systems

A plurality of time division duplex (TDD) platform pairs for use in a communications system which uses a TDD frame structure, each TDD platform pair comprising:

• a first communications platform;
• a second communications platform being coupled to said first communications platform, said first communications platform transmitting first data during a first frame, receiving second data during a second frame, said second communications platform receiving third data during said first frame, transmitting fourth data during said second frame;
• said first communications platform further comprises:
• a first crosslink antenna,
• a first crosslink transceiver coupled to said first crosslink antenna,
• a first subscriber link antenna,
• a first subscriber link transceiver coupled to said first subscriber link antenna, and
• a first controller coupled to said first crosslink transceiver and coupled to said first subscriber link transceiver;
• and
• said second communications platform further comprises:
• a second crosslink antenna,
• a second crosslink transceiver coupled to said second crosslink antenna,
• a second subscriber link antenna,
• a second subscriber link transceiver coupled to said second subscriber link antenna, and
• a second controller coupled to said second crosslink transceiver and coupled to said second subscriber link transceiver, said first communications platform being coupled to said second communications platform using a crosslink established between said first crosslink antenna and said second crosslink antenna;
• and
• said first subscriber link transceiver transmits said first data during a second sub-frame in said first frame and said second subscriber link transceiver receives said second data during a first sub-frame in said second frame.

A method of operating a time division duplex (TDD) platform pair, the method comprising the steps of:

• a) determining if a current frame has a count that is an odd number or an even number;
• b) when said count is said odd number, operating a first communications platform in a transmit mode during said current frame;
• c) when said count is said odd number, operating a second communications platform in a receive mode during said current frame;
• d) when said count is said even number, operating said first communications platform in said receive mode during said current frame;
• and
• e) when said count is said odd number, operating said second communications platform in said transmit mode during said current frame.

A method of operating a time division duplex subscriber unit (TDDSU), the method comprising the steps of:

• a) establishing a first link with a first communications platform in a TDD platform pair;
• b) establishing a second link with a second communications platform in said TDD platform pair;
• c) receiving first data from said first communications platform using said first link during a first frame, said first frame being in a TDD frame structure established by said TDD platform pair;
• d) transmitting third data to said second communications platform using said second link during said first frame;
• e) transmitting second data to said first communications platform using said first link during a second frame, said second frame being in said TDD frame structure established by said TDD platform pair;
• f) receiving fourth data from said second communications platform using said second link during said second frame;
• and
• g) processing said first data, said second data, said third data, and said fourth data.