A Two-Layered Shared Tree Multicast Routing Algorithm for Software Defined Hybrid Satellite-Terrestrial Communication Networks

Dynamic routing and congestion control are two major problems in software-defined hybrid satellite-terrestrial multicast networks research. Due to terrestrial users being allowed to join or leave the multicast group at any time and the differences between the satellite and the terrestrial networks, many multicast routing algorithms reroute rapidly and thus increase the rerouting overheads. Meanwhile, the congestion ratio is increased by some hot nodes of satellite-terrestrial link transmission paths. This paper focuses on rerouting overheads and congestion problems in satellite-terrestrial multicast networks. We present a satellite-terrestrial network architecture with the Software-Defined Networking (SDN) features to offer dynamic multicast services for terrestrial users. A Two-Layered Shared Tree Multicast (TSTM) routing algorithm is proposed to achieve efficient dynamic multicast group management, address the trade-off between bandwidth consumption and rerouting overheads. The algorithm also implements congestion control by using a load factor to reflect on the global network bandwidth usage in routing calculations. This algorithm balances the rerouting frequencies of satellite and terrestrial networks to decrease the rerouting overheads and also reduces the network congestion ratio. The simulation shows TSTM decreases rerouting cost, user time delay, and node congestion ratio compared with the locality-aware multicast approach (LAMA).

Quantifying the Density of mmWave NR Deployments for Provisioning Multi-Layer VR Services

The 5G New Radio (NR) technology operating in millimeter wave (mmWave) frequency band is designed for support bandwidth-greedy applications requiring extraordinary rates at the access interface. However, the use of directional antenna radiation patterns, as well as extremely large path losses and blockage phenomenon, requires efficient algorithms to support these services. In this study, we consider the multi-layer virtual reality (VR) service that utilizes multicast capabilities for baseline layer and unicast transmissions for delivering an enhanced experience. By utilizing the tools of stochastic geometry and queuing theory we develop a simple algorithm allowing to estimate the deployment density of mmWave NR base stations (BS) supporting prescribed delivery guarantees. Our numerical results show that the highest gains of utilizing multicast service for distributing base layer is observed for high UE densities. Despite of its simplicity, the proposed multicast group formation scheme operates close to the state-of-the-art algorithms utilizing the widest beams with longest coverage distance in approximately 50–70% of cases when UE density is λ≥0.3. Among other parameters, QoS profile and UE density have a profound impact on the required density of NR BSs while the effect of blockers density is non-linear having the greatest impact on strict QoS profiles. Depending on the system and service parameters the required density of NR BSs may vary in the range of 20–250 BS/km2.

Application Analysis of New Internet Multimedia Technology in Optimizing the Ideological and Political Education System of College Students

Ideological and political education is the most important part of the daily education management of college students. The methods and methods of ideological and political education are very old, and students’ learning efficiency is very low. How to use ideological and political education technology combined with modern technology for teaching has become a current research hotspot. Based on this background, this article proposes to use a new type of Internet multimedia technology interactive teaching. In the ideological and political network multimedia teaching system, use occasions suitable for IP multicast applications, such as broadcast teaching, group discussions, and on-demand courseware. Among these functions, the IP multicast mechanism is appropriately used. The adoption of the extended conversation node scales each conversation group to a multicast group, and the members of the multicast group represent the participants, which brings convenience and ease of management. Through case study analysis, it can be seen that this method can reduce the burden on the system and improve efficiency, and the number of multicast members is unlimited, which has a very good auxiliary effect on course learning. Through the Internet multimedia technology, the innovation of ideological and political education has been realized, the learning environment of students has been improved, the ways of ideological and political education have been broadened, and the education system has been better optimized.

Performance of MAODV and ODMRP Routing Protocol for Group Communication in Mobile Ad Hoc Network

A MANET is a self-conFigureuring system of mobile hosts connected by wireless links. The routers are free to move randomly and organize themselves arbitrarily; thus, the network's wireless topology may change rapidly and unpredictably. Routing is the process of exchanging information from one station to the other stations of the network. Multicasting is a popular mechanism for supporting group communication. In a multicast session, the sender transmits only one copy of each message that is replicated within the network and delivered to multiple recipients. This multicast routing is highly deal with self-organized network in recent days due to its broadcast characteristics. However, devising multicast protocols to provide group communications in mobile ad-hoc networks is significantly more complicated, because of the wireless medium, changing topology, battery power and available bandwidth as well. This paper, evaluates two prominent on-demand multicast routing protocols for group communication, namely, Multicast Ad hoc On-Demand Distance Vector (MAODV) and On-Demand Multicast Routing Protocol(ODMRP) as increasing number of multicast sources and receivers in both single-active multicast group and multi-active multicast group in the network.

Improving Energy Efficiency of Multimedia Content Dissemination by Adaptive Clustering and D2D Multicast

While achieving desired performance, there exist still many challenges in current cellular networks to support the multimedia content dissemination services. The conventional multimedia transmission schemes tend to serve all multicast group members with the data rate supported by the receiving user with the worst channel condition. The recent work discusses how to provide satisfactory quality of service (QoS) for all receiving users with different quality of experience (QoE) requirements, but the energy efficiency improvement of multimedia content dissemination is not its focus. In this paper, we address it based on adaptive clustering and device-to-device (D2D) multicast and propose an energy-efficient multimedia content dissemination scheme under a consistent QoE constraint. Our scheme extends the recent work with the proposed K-means-based D2D clustering method and the proposed game-based incentive mechanism, which can improve energy efficiency of multimedia content dissemination on the premise of ensuring the desired QoE for most multicast group members. In the proposed scheme, we jointly consider the cellular multicast, intracluster D2D multicast, and intercluster D2D multicast for designing the energy-efficient multimedia content dissemination scheme. In particular, we formulate the energy-efficient multicast transmission problem as a Stackelberg game model, where the macro base station (MBS) is the leader and the candidate D2D cluster heads (DCHs) are the followers. Also, the MBS acts as the buyer who buys the power from the candidate DCHs for intracluster and intercluster D2D multicast communications, and the candidate DCHs act as the sellers who earn reward by helping the MBS with D2D multicast communications. Through analyzing the above game model, we derive the Stackelberg equilibrium as the optimal allocation for cellular multicast power, intracluster D2D multicast power, and intercluster D2D multicast power, which can maximize the MBS’s utility function. Finally, the proposed scheme is verified through the simulation experiments designed in this paper.