Antenna synchronization for coherent network MIMO

摘要

The invention relates to a method for synchronizing RF antenna signals (5a to 5i) of a plurality of RF antenna sites (3a to 3i) arranged at different locations of a radio transmission system (1b), the method comprising; generating a reference signal (7) in a reference oscillator (6) located at a central unit (2) of the radio transmission system (1b), transmitting the reference signal (7) as an optical signal from the central unit (2) to the RF antenna sites (3a to 3i) via a plurality of optical fiber links (9a″ to 9i″), and using the transmitted reference signal (7) for synchronizing the RF antenna signals (5a to 5i) of the different RF antenna sites (3a to 3i), The invention also relates to a radio transmission system (1b).

主权项

1. A method for synchronizing Radio Frequency (RF) antenna signals of a plurality of RF antenna sites arranged at different locations of a radio transmission system, the method comprising:
generating a reference signal having a radio frequency in a central reference oscillator located at a central unit of the radio transmission system; transmitting the reference signal as an optical signal from the central unit to the RF antenna sites via optical fiber links; using the transmitted reference signal for synchronizing the RF antenna signals of the different antenna sites; using the reference signal by at least two of the RF antenna sites for generating a carrier signal for at least two of the RF antenna signals; and transmitting the at least two RF antenna signals by at least two of the RF antenna sites; wherein said optical signal comprises two components having different wavelengths and wherein said method further comprises generating a clock reference as a difference between the two components by a frequency mixer of the RF antenna sites.