Patent ID: 9735863
Date: 2017-08-15
CPC Classifications: H04B,H04W

Claim:
1. A method for clock distribution and recovery for an optical mobile backhaul, comprising: generating an Orthogonal Frequency-Division Multiple Access (OFDMA) signal with a transmitter (Tx) at an optical line terminal (OLT), the OFDMA signal generated by assigning orthogonal subcarriers to different cell sites through digital signal processing; generating two electrical clock signals: a baseband square wave clock, Csquare, that controls Tx-side digital logic and a sine wave clock Csine, that controls a digital to analog converter (DAC); combining the OFDMA signal and clock signals; intensity-modulating the resulting joint OFDMA signal+clock signal; optically multiplexing aggregate OFDMA signal+clock signals on multiple wavelengths with a dense wavelength division multiplexing DWDM λ-spacing; distributing at a remote node (RN) each wavelength by a de-multiplexer (Demux) to a designated general small cell area to which cell sites are connected by optical splitters; and photodetecting and digitizing received OFDMA signal and clock signals at each optical network unit (ONU), wherein downstream (DS) information for each cell is then digitally extracted and prepared for wireless radio frequency (RF) transmission over an air interface: wherein the clock signals are time and frequency synchronous with the OFDMA signal due to optical locking that occurs during intensity modulation of a combined Tx-side data and clock signal.