The fast increasing of mobile data traffic, and the stringent requirements of the emerging services in terms of latency and bandwidth, have spurred numerous influences for the change of Cloud Radio Access Network (C-RAN) and cloud computing. MEC enabled C-RAN have emerged as promising candidates for the next generation access network techniques to accommodate the fast growing IoT traffic and improve the performance of IoT services. Deploying MEC servers in C-RAN, which brings IoT services to the edge network, not only improve users quality of service (QoS), but also alleviates the network traffic of core network. The deployment performance of MEC servers is, however, highly related to the workload assignment. Therefore, the deployment mechanism of MEC servers and workload assignment scheme would jointly affect QoS of users, economic benefits of operators. In this paper, we jointly consider MEC deployment and workload assignment for minimizing the sum of deployment cost and delay in C-RAN based on optical rings. Simulation results showed that the proposed algorithm not only minimizes the total cost (MEC deployment cost and E2E delay), but also demonstrate good trade-off between deployment cost and average delay.
The TDM-PON is a promising candidate for mobile fronthaul due to its high scalability and cost effectiveness. Mobile fronthaul traffic has a strict one-way latency requirement of about 250μs. Therefore, latency is a critical issue for applying TDM-PON to mobile fronthaul. The traditional equal-length transmission division scheme can reduce the latency in TDM-PON. However, the scheme can still be optimized in terms of latency and bandwidth utilization. We propose a variable-length transmission division scheme to further reduce the latency in TDM-PON and improve the bandwidth utilization compared with the traditional scheme.
With the rapid growth of 4G mobile network and vehicular network services，mobile terminal users have increasing demand on data sharing among different radio remote units (RRUs) and roadside units (RSUs). Meanwhile, commercial video-streaming, video/voice conference applications delivered through peer-to-peer (P2P) technology are still keep on stimulating the sharp increment of bandwidth demand in both business and residential subscribers. However, a significant issue is that, although wavelength division multiplexing (WDM) and orthogonal frequency division multiplexing (OFDM) technology have been proposed to fulfil the ever-increasing bandwidth demand in access network, the bandwidth of optical fiber is not unlimited due to the restriction of optical component properties and modulation/demodulation technology, and blindly increase the wavelength cannot meet the cost-sensitive characteristic of the access network. In this paper, we propose a software defined multi-OLT PON architecture to support efficient scheduling of access network traffic. By introducing software defined networking technology and wavelength selective switch into TWDM PON system in central office, multiple OLTs can be considered as a bandwidth resource pool and support flexible traffic allocation for optical network units (ONUs). Moreover, under the configuration of the control plane, ONUs have the capability of changing affiliation between different OLTs under different traffic situations, thus the inter-OLT traffic can be localized and the data exchange pressure of the core network can be released. Considering this architecture is designed to be maximum following the TWDM PON specification, the existing optical distribution network (ODN) investment can be saved and conventional EPON/GPON equipment can be compatible with the proposed architecture. What’s more, based on this architecture, we propose a dynamic wavelength scheduling algorithm, which can be deployed as an application on control plane and achieve effective scheduling OLT wavelength resources between different OLTs based on various traffic situation. Simulation results show that, by using the scheduling algorithm, network traffic between different OLTs can be optimized effectively, and the wavelength utilization of the multi-OLT system can be improved due to the flexible wavelength scheduling.
We address the problem of content delivery network for HD-VoD service. Content delivery network (CDN) is a network
that puts users closer to the storage resources. The conventional CDN structure for video delivery is based on the
IP-over- WDM network which could not meet the requirements for HD-VoD service, such as high-speed transfer and low
latency and jitter. A novel all-optical CDN network model for high-definition VoD service is proposed in this paper. We
introduce the concept of optical timeslot in the lightpath provision. A mini-control plane mechanism based on ring
topology is also designed for the fast optical timeslot setup/release. Simulation results and analysis of our model is
showed at the end of paper.