Nowadays, cognitive radio (CR) is considered the key technology to deploy wireless nodes that are able to adapt their\ntransmission parameters based on the characteristics of the environment. In our previous works, we leveraged the\nreconfigurability properties offered by the CR technology to implement Cognitive Wireless Mesh Networks (CMNs)\noperating on the 2.4-GHz industrial, scientific, and medical (ISM) band. Urban-X, a new architecture for Multi-radio\nCognitive Mesh Networks, self-configures and self-adapts to the dynamic interference conditions experienced on the\nWi-Fi channels in dense urban environments. Urban-X estimates traffic load of existing users outside the mesh in each\nchannel and utilizes less occupied channels opportunistically. In such dynamic environment, a transport layer protocol\ncan suffer from variation in delay and available bandwidth due to spectrum sensing and mobility. Several TCP solutions\nfor the CWMNs have been proposed but they could not be employed for implementation due to complexity and\ninefficiency. Instead, we adopt network function virtualization (NFV) technique which allows to instantiate virtualized\nnetwork functions (VNFs) dynamically on demands. For this, we propose overall architecture of NFV framework for the\nCMNs and apply TCP accelerators (ACC) VNFs to improve TCP throughput as a case study. Simulation results show\nTCP-ACC VNF can achieve a notable performance enhancement compared to previous TCPs for the CMNs.
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