Multi-radio multi-channel technology can efficiently improve the multi-hop wireless networks' bandwidth and throughput,so that it has been becoming the researching hot spot.Among the so many researching key issues about the multi-radio multi-channel technology,wireless channel assignment and management are more important and difficult.This paper proposed a new dual-radio multi-channel MAC protocol using the standard 802.11 WiFi NIC,named as DIM(Dual-Interface Management MAC protocol).DIM can optimize the channel assignment by applying the channel conflict model,and take full use of the available IEEE802.11 wireless channels with little command on hardwire configuration.The simulation results show that DIM has more network throughput and less latency of packets delivery.
The particle filter is applicable to any kind of state estimation in nonlinear non-Gaussian system,and it has a wide range of application and flexibility.The choice of the proposed distribution directly determines the estimation accuracy and estimation efficiency.Aiming at the difficulty,a particle swarm optimization particle filter is proposed to determine the proposed distribution.The particle swarm optimization algorithm as a new intelligence algorithm also adapts all types of non-linear non-Gaussian systems,using the algorithm to determine the proposed distribution of particle filter ensures a wide range of application of particle filter and improves the estimation accuracy.Finally,simulation of multi-user detection of CDMA system was realized based on particle filter in Alpha stable noise environment.The results showed that using intelligent algorithms to determine the proposed distribution of the particle filter greatly improved the estimation accuracy.
Recently, data integrity in computer major becomes concern. The attackers are capable of using various methods to intrude computer network system. The phenomena of confidential information being tampered with or disclosed are emerging everywhere. Hardware-based attacks have emerged and have caused tremendous losses even threaten national security. Existing most of integrity verification designs have the characters of high operation overhead and only protect main memory. This paper presented an integrity protection scheme which can protect main memory and hard disk simultaneously. The scheme maintains an array on trusted on-chip storage to verify the data integrity. It can implement verification through each memory operations. Evaluation results showed that our scheme can protect data integrity of single processor with low overhead and high performance.
Focus on this question of high verification overhead of hash tree memory protection scheme, this paper proposed a hash tree optimize method called AH-Tree. Utilizing the locality character of memory accessing, the memory is divided into two parts and an asymmetric hash tree (AH-Tree) is constructed. The advantage of AH-Tree is low average operation overhead. The analysis and experiment results proved that the proposed scheme has shorter average verification path and better verify efficiency than hash tree scheme. AH-Tree is a feasible memory integrity protection scheme.
The rise of 5G Tactile Internet has attracted enormous attentions from the communication society for low latency applications, such as Vehicle to Vehicle (V2V) and Vehicle to Infrastructure (V2I) communications in intelligent transportation systems, which have already been considered as key use cases of the Tactile Internet. In the current practice, there are two leading solutions for vehicular communications: 802.11 p standardized by IEEE, and LTE-V suggested by Chinese mobile service providers and car manufacturers. With the pros and cons from both ends, it is feasible to leverage both 802.11p and LTE networks in order to fully exploit their advances. In this paper, we investigate low-latency vehicular communications in L TE-802.11p hybrid networks. In particular, we propose a novel vertical handoff protocol for seamless switching between 802.11p and LTE networks. We first study Quality-of-Service (QoS) characteristics of LTE and 802.11 p networks for vehicular communications with extensive simulations in NS-3, and develop a new model to reveal the relationship between communication delay and vehicle's position. Based on this model, we develop the proposed protocol for seamless handoff between 802.11p and LTE networks aiming at minimizing the communication delay in vehicular communications. Simulation results confirm the efficiency of the proposed handoff protocol.
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