Da Guo

Energy-Saving Power Allocation Scheme for Relay Networks Based on Graphical Method of Classification

With the development of mobile communication, there is a lot of research concentrating on cooperative relaying. However, the previous studies mainly focus on the transmission performance. In this paper, we considered a two-hop relay cooperative network, and proposed an energy-saving power allocation scheme based on graphical method of classification, so as to solve the problems of nonlinear constraints in the network scenario. As the scheme figures show, the proposed scheme can greatly reduce the difficulty of solving the problem, and from the simulation results, it can be concluded that the proposed scheme has realized the goal of energy-saving, and it improved the quality of service QoS at the same time.

The Energy Efficiency Research of Traffic Offloading Mechanism for Green Heterogeneous Networks.

Opportunistic Network as a novel networking, taking advantage of meeting opportunities of mobile nodes, completes the message transmission from the source node to the destination node through the way of each hop. Mobility model decides how the nodes move and is used to analyze network performance with various protocols, such as routing protocols, data dissemination protocols, etc. Currently many mobility models are proposed by researchers. To evaluate these mobility models, an analysis method is proposed. So we propose a method by analyzing mobile distance to assess node mobility models. This paper firstly introduced the commonly used mobility models based on ONE simulation platform, and then a calculation method of node mobile distance is put forward. Next, it was simulated and discussed that we have considered the nodes mobility features by mobile distance. Finally, we use the node contact duration and node inter-contact time as a validation, to make an evaluation for node mobility model.

A HMM-based content forwarding strategy in LEO satellite system

Using the low earth orbit (LEO) satellite technology to provide high capacity and high speed data service for the users, has been one of the most popular research hotspots in LEO satellite communication system. Whereas, the traditional researches in the field of satellite communication mainly focus on the optimization of channel resource allocation, which is based on the improvement of data transmission rate and reliability. Different from the traditional research, this paper considers the popularity of content in different earth station (ES) from the users perspective. Then we optimize the channel resources allocation between LEO satellite and ESs, and among ESs simultaneously, under the premise of maximizing the content forwarding capacity of the LEO satellite. In particular, the content forwarding of LEO satellite is modeled as hidden Markov model (HMM), and an optimal content forwarding algorithm based on Viterbi is proposed. At the same time, a multi-domain channel resource allocation algorithm based on HMM (MCR-H) is proposed to optimize the LEO satellite communication system. Numerical results demonstrate the performance and advantage of our new scheme.

An Energy-Saving Algorithm Based on Base Station Sleeping in Multi-Hop D2D Communication

Nowadays, with the increasing awareness of environmental and economic issues, energy efficiency has received an enormous amount of attention. In this paper, we investigate an energy-saving algorithm called Greedy Base Station Sleeping (G- BSS), based on clustering for Device-to-Device (D2D) communication in cellular network and derive the energy utility function to evaluate energy consumption of the implementation scenario. In addition, a novel user association scheme is developed for the first time to solve the communication problem of users in sleep cells, in which the D2D clusters in sleep cells associate to the selected inter-CH (Cluster Head) in neighbor cells according to location information and residual energy, namely forming a merger cluster. Extensive simulation results confirm that the proposed algorithm reduces efficiently energy consumption and achieves low delay.

Investigation on Mobility Model in Opportunistic Network

Opportunistic Network as a novel networking, taking advantage of meeting opportunities of mobile nodes, completes the message transmission from the source node to the destination node through the way of each hop. Mobility model decides how the nodes move and is used to analyze network performance with various protocols, such as routing protocols, data dissemination protocols, etc. Currently many mobility models are proposed by researchers. To evaluate these mobility models, an analysis method is proposed. So we propose a method by analyzing mobile distance to assess node mobility models. This paper firstly introduced the commonly used mobility models based on ONE simulation platform, and then a calculation method of node mobile distance is put forward. Next, it was simulated and discussed that we have considered the nodes mobility features by mobile distance. Finally, we use the node contact duration and node inter-contact time as a validation, to make an evaluation for node mobility model.

Single Link Routing Protocol for Wireless Sensor Network

In this paper, we have proposed a single link routing protocol for wireless sensor network for the pre-deployed nodes in areas such as Fire Protection and Wildlife Surveillance. In our routing protocol, the single link was taken into consideration, which always appeared by the lack of device energy, the bad environment or sleep/wake of nodes themselves. To solve the problem caused by that condition, we have proposed one method of detecting unidirectional links by the Neighbor Matrix described in our paper. Once we have maintained the whole routing information of the pre-deployed nodes, the whole network could be accessible by every available path, of course, single link is included; yet the single link is only available when transmission is from the upstream node to the downstream node. This manner not only solves the shortage of traditional one, but also improves the transmission rate and efficiency of the network. From the simulation results, the proposed scheme can achieve remarkable performance improvements in terms of network efficiency, network delivery and end-to-end delay when compared with the traditional one.

An optimization model for fragmentation-based routing in delay tolerant networks

The explosive growth of mobile data traffic has raised big penetration to cellular network. Fortunately, offloading part of traffic through Delay Tolerant Network (DTN) would be a promising option to relieve load pressure. However, the existing routing strategies designed for DTNs are inappropriate in offloading scenario, where i) large data item would take on the dominance of mobile traffic, ii) centralized control can be exploited with merge between DTN and cellular network. To improve the routing performance of large data transmission, we propose a novel optimization model by creating two-tier solution space based on fragmentation, maximizing the probability that the requested data item is successfully delivered before expiration, taking limited buffer space as constraint metric. Moreover, a specific routing scheme is instantiated from our model, which is supported by uniform fragmentation and fine-grained path selection. Extensive trace-driven simulations show that our scheme is more appropriate for offloading case with outstanding performance in terms of replication overhead and acceptable routing capability.创新点通过容断容迟网络分流数据,已成为缓解蜂窝系统流量负载的前瞻性举措。然而,针对容断容迟网络的路由策略不适用于具有以下特征的分流场景:1)大容量文件在移动流量中的占比较高;2)蜂窝网络引入了集中化控制的优势。因此,本文创新性地以节点缓存空间的有限性为约束条件,以最大化数据成功递交率为优化目标,基于分片传输策略,提出了具有双层解空间的优化模型。此外,利用均匀分片策略及细粒度的路径选择机制,实现了基于上述优化模型的路由策略,在大幅度降低网络副本开销的情况下保证了路由传输性能。

Data distribution mechanism over opportunistic networks with limited epidemic

Most of data distribution mechanism in Opportunistic Networks is derived by Epidemic data distribution, and Epidemic data distribution means that when each node meets another node, it may copy its own messages and transfer to another node. On the one hand, the copies improve the forwarding rate, and reduce the transmission delay. However, on the other hand, energy consumption increases and network survival time is reduced because the copies consume transmission resource. Therefore, copy number should be under control. In this paper, we first introduce the existing routing strategy based on Epidemic briefly, and present the Epidemic routing protocol analysis model and copy control mechanism based on the limited Epidemic in Opportunistic Networks. Then based on the limited copies scheme (LCS), we propose an energy balance scheme (EBS), the results show that EBS can improve the network survival time.

An Novel Message Delivery Mechanism in Opportunistic Networks

Opportunistic networks are ad hoc networks which can not maintain end-to-end paths between source and destination, especially in the environment of without fully-connective. Therefore, the problems brought about by the routing protocol and resource allocation are more serious than those by the traditional networks. In order to improve message delivery ratio and reduce message delivery delay, this paper puts forward a data transmission mechanism based on forward and replication, which takes community detection and delivery weight into account simultaneously. Firstly, our proposal is that we calculate contact probability through tracking nodes’ movement and designing the algorithm of community detection. Secondly, we estimate delivery weight based on historical data and use the corresponding strategy for message forwarding. Finally, our results show that the proposed mechanism is superior to that of the existed ones in terms of message delivery ratio and message delivery delay.

Quantum-Inspired Shuffled Frog Leaping Algorithm for Spectrum Sensing in Cooperative Cognitive Radio Network

Cognitive radio technology has been proposed to improve spectrum efficiency by having the cognitive radios act as secondary users to opportunistically access under-utilized frequency bands. Spectrum sensing, as a key enabling functionality in cognitive radio networks, needs to reliably detect signals from licensed primary radios to avoid harmful interference. In this paper, we propose a Quantum-inspired frog leaping algorithm (QSFLA) based on frog leaping algorithm and we evaluate the performance of the QSFLA through some classical benchmark functions. Simulation results for cognitive radio system are provided to show that the designed spectrum sensing algorithm is superior to some previous spectrum sensing algorithm in probability of detection, convergence rate and accurate convergence value.