Optical fiber and millimeter wireless could be commercially ready in 3-5 years and will deliver 1-10 Gbps (gigabit per second) communication speed.
Hybrid fiber-wireless networks incorporating WDM technology for fixed wireless access operating in the sub-millimeter-wave and millimeter-wave (mm-wave) frequency regions are being actively pursued to provide untethered connectivity for ultrahigh bandwidth communications. The architecture of such radio networks requires a large number of antenna base-stations with high throughput to be deployed to maximize the geographical coverage with the main switching and routing functionalities located in a centralized location. The transportation of mm-wave wireless signals within the hybrid network is subject to several impairments including low opto-electronic conversion efficiency, fiber chromatic dispersion and also degradation due to nonlinearities along the link. One of the major technical challenges in implementing such networks lies in the mitigation of these various optical impairments that the wireless signals experience within the hybrid network. In this paper, we present an overview of different techniques to optically transport mm-wave wireless signals and to overcome impairments associated with the transport of the wireless signals. We also review the different designs of subsystems for integrating fiber-wireless technology onto existing optical infrastructure.
The wavelength division multiplexed passive optical network (WDM-PON) is an attractive upgrade solution for current access networks due to its large capacity, ease of upgradeability, and security guarantee. Such a network will provide a future-proof solution to delivering bandwidth-intensive services to end-users. Nonetheless, the lack of cost-effective optical sources at the end-user site remains as a dominant factor that is impeding the widespread uptake of WDM-PONs.