Wavelength Assignment Scheme of ONUs in Hybrid TDM/WDM Fiber-Wireless Networks

Recently, the hybrid Fiber-Wireless (FiWi) access network integrating passive optical networks (PONs) and wireless mesh networks (WMNs) has been proposed to provide the high bandwidth, low cost and ubiquitous Internet access. Typically, for the PON subnetwork of FiWi networks, a hybrid TDM/WDM architecture has been applied due to its cost efficiency and the high bandwidth provided by multiple wavelengths carried in the optical trunk. In such hybrid TDM/WDM FiWi networks, we aim to maximize the overall network throughput and meanwhile to find an appropriate wavelength assignment scheme of ONUs to achieve the approximate maximal throughput with the minimum number of wavelengths to be used. In this paper, we first obtain the maximal achievable throughput at ONUs and then get the minimal number of wavelength to be used. Given the number of wavelengths, we first use LP-based formulations to estimate the expected traffic load range at each ONU and then proposed the Approximate Wavelength Assignment(AWA) algorithm to calculate the appropriate traffic load at each ONU and obtain the proper wavelength assignment scheme of ONUs. We also verify the efficiency of the wavelength assignment scheme obtained through AWA algorithm. Simulation results strongly validate our algorithm.