دانلود رایگان مقاله پروتکل تخصیص منابع ​​کنترل دسترسی مؤثر برای رادیو بیش از فیبر شبکه دسترسی

ABSTRACT

Users’ rapidly increasing demands for bandwidth and mobility in conjunction with the surge of delaysensitive applications, creates the necessity for further research and development of new energy- and cost-effective technologies such as radio-over-fiber (RoF) and radio-and-fiber (R&F). The research community is dealing with medium access control (MAC) protocol design for RoF networks, so that it can support bandwidth-demanding multimedia services such as voice over IP, video on demand, video conferencing, etc. In this work, a novel MAC protocol for RoF access networks is proposed, which is based on a modification of the multipoint control protocol (MPCP). The network’s decision centre receives detailed feedback from the mobile client queues via MPCP’s GATE/REPORT mechanism so as to efficiently allocate the bandwidth and the wavelength resources in a dynamic manner. The novelty of this protocol is that since wavelength reuse is achieved a single wavelength can be used by more than one remote antenna unit (RAU). The proposed MAC protocol also adapts its operation according to the clients’ actual traffic demands and manages to exploit the huge capacity that the optical medium provides. Furthermore, a best-fit algorithm is applied in order to achieve further optimization. Simulation results reveal the superior performance and the better scalability of the proposed protocol compared with similar proposals reported in the literature.

6. Conclusion

We have introduced a novel concept of MAC protocols for 60 GHz RoF networks that employs wavelength reuse in the optical part of the network. The RoF consists of an EPON in a bus topology and a 60 GHz wireless network. The proposed protocol employs MPCP in order to arbitrate traffic with REPORT and GATE messages. The protocol results in dynamic bandwidth allocation among the clients, dynamic wavelength reassignment and simultaneous wavelength use among RAUs. The proposed protocol’s performance is evaluated via simulations with different load conditions, different number of RAUs and different number of wavelengths. Performance evaluation results show better scalability, especially with fewer resources, and huge improvements in the network’s metrics including throughput and mean packet delay compared with competing protocols. The huge improvement in performance is achieved mainly through wavelength reuse among RAUs, which means simultaneous use of a wavelength from more than one RAU and therefore better wavelength utilization.