We provide an overview of an architecture of today's Internet streaming media delivery networks and describe various problems that such systems pose with regard to video coding. We demonstrate that based on the distribution model (live or on-demand), the type of the network delivery mechanism (unicast versus multicast), and optimization criteria associated with particular segments of the network (e.g., minimization of distortion for a given connection rate, minimization of traffic in the dedicated delivery network, etc.), it is possible to identify several models of communication that may require different treatment from both source and channel coding perspectives. We explain how some of these problems can be addressed using a conventional framework of temporal motion-compensated, transform-based video compression algorithm, supported by appropriate channel-adaptation mechanisms in client and server components of a streaming media system. Most of these techniques have already been implemented in RealNetworks(R) RealSystem(R) 8 and its RealVideo(R) 8 codec, which we use throughout the paper to illustrate our results.

Video Coding for Streaming Media Delivery on the Internet

In the context of the 5G ecosystem, the integration between the terrestrial and satellite networks is envisioned as a potential approach to further enhance the network capabilities. In light of this integration, the satellite community is revisiting its role in the next generation 5G networks. Emerging technologies such as Software-Defined Networking (SDN) which rely on programmable and reconfigurable concepts, are foreseen to play a major role in this regard. Therefore, an interesting research topic is the introduction of management architecture solutions for future satellite networks driven by means of SDN. This anticipates the separation of the data layer from the control layer of the traditional satellite networks, where the control logic is placed on programmable SDN controllers within traditional satellite devices. While a centralized control layer promises delay reductions, it introduces additional overheads due to reconfiguration and migration costs. In this paper, we propose a method to quantify the overhead imposed on the network by the aforementioned parameters while investigating the use-case scenario of an SDN-enabled satellite space segment. We make use of an optimal controller placement and satellite-to-controller assignment which minimizes the average flow setup time with respect to varying traffic demands. Furthermore, we provide insights on the network performance with respect to the migration and reconfiguration cost for our proposed SDN-enabled architecture. Finally, we compare our proposed space segment SDN-enabled architecture with alternative solutions in the state-of-the-art given the aforementioned performance metrics.

/pdf/design-and-evaluation-of-reconfigurable-sdn-leo-45rzjg4gbc.pdf

Design and Evaluation of Reconfigurable SDN LEO Constellations

The integrated information network is a large capacity information network that integrates various communication platforms on the ground, at sea, in the air and in the deep air through the inter-satellite and satellite-ground links to acquire information accurately, process it quickly, and transmit it efficiently. The satellite communication, as an important part of integrated information networks, is one of main approaches to acquire, process and distribute communication information and resources. In this paper, based on current researches of the satellite communication network, we put forward a 3-layer satellite communication network model based on the Software Defined Network (SDN). Meanwhile, to improve current routing policies of the Low Earth Orbit (LEO) satellite communication network, we put forward an Adaptive Routing Algorithm (ARA) to sustain the shortest satellite communication link. Experiment results show that the proposed method can effectively reduce link distance and communication delay, and realize adaptive path planning.

An adaptive routing algorithm for integrated information networks

Summary In view of the problems of low routing efficiency, complex control process, and difficult network management in big data environment in the traditional integrated space‐terrestrial network,...

Routing algorithm design of satellite network architecture based on SDN and ICN

The low earth orbit (LEO) satellite network can benefit from software-defined networking (SDN) by lightening forwarding devices and improving service diversity. In order to apply SDN into the network, however, reliable SDN control links should be associated from satellite gateways to satellites, with the wireless and mobile properties of the network taken into account. Since these characteristics affect both control link association and gateway power allocation, we define a new cross layer SDN control link problem. To the best of our knowledge, this is the first attempt to explore the cross layer control link problem for the software-defined satellite network. A logically centralized SDN control framework constrained by maximum total power is introduced to enhance gateway power efficiency for control link setup. Based on the power control analysis of the problem, a power-efficient control link algorithm is developed, which establishes low latency control links with reduced power consumption. Along with the sensitivity analysis of the proposed control link algorithm, numerical results demonstrate low latency and high reliability of control links established by the algorithm, ultimately suggesting the feasibility, both technical and economical, of the software-defined LEO satellite network.

/pdf/cross-layer-optimization-of-wireless-control-links-in-the-4cck2a59pt.pdf

Cross Layer Optimization of Wireless Control Links in the Software-Defined LEO Satellite Network

In the next generation network, Low Earth Orbit (LEO) satellite networks are indispensable due to global seamless coverage and lower orbit altitude to maintain low- latency communication. However, the time-variant topologies of satellite networks bring great challenges to network management and robust routing algorithms design. Furthermore, non-uniform distribution of users will cause load unbalance among intersatellite links (ISL). In this paper, we embrace the idea of software-defined networking (SDN) to divide the satellite network into control and data plane. The satellites as switches only forward the data so that the on-board processing capacity is minimized. To realize flexible centralized management of the satellite network, we design a master controller and several slave controllers around the earth. Based on this, we propose a software defined routing algorithm (SDRA) which can obtain the optimal routing path by centralized routing strategy. With collecting congestion status of the satellites in real time, the controllers can bypass the congested ISLs when calculating routing paths. Compared with other routing algorithms, the proposed SDRA reduces the queueing delay by a nearly half, achieves a better traffic distribution and has better performance in terms of end-to- end delay, packet dropping probability and network throughput.

Software defined routing algorithm in LEO satellite networks

The invention relates to a various illumination face identification method based on small sample emulating and sparse expression and belongs to the technical field of image processing. The method comprises the steps of: creating an image illumination collection and combining into a virtual combined sample with an entropy image method, acquiring the sparse expression of the individual to be identified on a complete face base from the virtual combined sample by using a sparse expression method, rebuilding an original detected image after substituting the sample rebuilding factor in a classification band-pass function so as to acquire a residual error between each type of rebuilt sample and the original detected image, and guiding the residual error into a category identifying formula to acquire an indentifying result. The invention solves the problem that the traditional sparse frame requires huge learning sample and achieves an excellent identifying property. The method of the invention obtains a better robustness under shielding or various illumination conditions and acquires better properties of sampling requirement, identifying ratio and man-machine interaction efficiency.

Various illumination face identification method based on small sample emulating and sparse expression

Time synchronization plays an important role in UANs, which need fine-grained coordination among nodes. Precise time synchronization is also needed for a variety of other coordinate tasks in UANs such as data fusion, TDMA scheduling, localization, power-saving and so on. Recently, time synchronization protocol for point-to-point with high propagation delay has been proposed, while time synchronization for multi-hop UANs is still an open issue. In this paper, we propose a multi-hop time synchronization scheme for Underwater Acoustic Networks (MSUAN). MSUAN includes three stages. In the first stage, we assign each node a level by establishing a path to the reference node. During the second phase, nodes realize synchronization by receiving synchronization packets both from it's parent node and neighboring nodes. The third stage re-synchronizes nodes because the clock may drift away without synchronization for long time. Mathematical analysis of MSUAN's synchronization error shows that the more time-stamps we get, the more accurate skew we will get. At the end, we use OPNET to simulate MSUAN, and the simulation result under pyramid topology shows that even the hop accumulates to 8, for MSUAN, the average offset error is maintained at about 58us and the average skew error is below 2ppm.

http://ieeexplore.ieee.org/iel5/6387510/6404774/06404923.pdf

Multi-hop time synchronization for Underwater Acoustic Networks

LoRa is a well-known Low-Power Wide-Area Network (LPWAN) specification that often uses a star topology to directly connect IoT devices to the gateway, which sends data to the network server. In practical deployment, determination of the number of gateways and their locations is the key problem in LoRa network planning. In this paper, we model LoRa network planning as a constrained clustering problem and propose an improved ISODATA algorithm to solve it. Simulation results show that, the packet reception rate and the average throughput can be improved by 23.30% and 23.51% compared with the basic ISODATA algorithm.

LoRa Network Planning Based on Improved ISODATA Algorithm

The invention relates to an FARIMA model Hurst parameter estimation method based on domain searching. An FARIMA time sequence of the self-similarity long-range dependency characteristic possessed by simulating the actual network flow is used as an estimation source, and a mode of combining a time-variance graph method and a searching method is adopted for carrying out accurate estimation of Hurst parameters. The method specifically comprises the following steps that 1), the FARIMA time sequence of the network flow which can be simulated and has the self-similarity long-range dependency characteristic is generated; 2), an experience section used for roughly estimating a time block of the variance-time graph method of the FARIMA sequence is determined; 3), the variance-time graph method is used for carrying out Hurst parameter estimation of the FARIMA time sequence in the experience section obtained in the step 2); 4), the step size and precision parameters of the search method are determined, and precise search estimation of the Hurst parameters is carried out close to a rough estimation value. Compared with the prior art, the precision of Hurst parameter estimation is greatly improved.

Cheng Zhi

Papers

Software defined routing algorithm in LEO satellite networks

Various illumination face identification method based on small sample emulating and sparse expression

Multi-hop time synchronization for Underwater Acoustic Networks

LoRa Network Planning Based on Improved ISODATA Algorithm

FARIMA model Hurst parameter estimation method based on domain searching