Multi-wavelength WiMAX-PONs with overlapping cells

An access network architecture integrating standard wireless signal formats over multi-wavelength splitter-PON based on radio over fiber (RoF) technology is demonstrated. Frequency division multiplexing (FDM) is applied to address individual base stations sharing a single wavelength. The extended wavelength band overlay overcomes the need for complex dispersion compensation techniques as it avoids the use of high frequency subcarriers in the FDM window. Also, it achieves enhanced network scalability to previously reported converged architectures as well as reduced component cost. Significantly, extended features of wireless networks have been presented through the application of overlapping cells to overcome the wireless spectrum congestion beyond current deployment scenarios and provide resilience for legacy PONs. To evaluate the network transmission characteristics, multiple IEEE802.16d channels, with 70 Mbits/s downstream and 40 Mbits/s upstream data rates, are frequency shifted around the same RF carrier and transmitted on two different wavelengths. The obtained results has demonstrated EVMs of -31 dB at ONU/BS remote antenna inputs and minimum 10-4 BERs bidirectionally over combined 20km and faded 330m overlapping micro-cells circumference without any error coding or relay techniques. The application of low-cost long-wavelength VCSEL array in upstream for colorless transmission demonstrated 0.7 dB power penalty to the received WiMAX channels in the OLT.