Applications supporting various multimedia data in wireless multimedia sensor networks (WMSNs) have specific QoS requirements on bandwidth, delay, and/or packet loss. Perception of applications' QoS requirements and detection of link states are indispensable for the design of QoS-aware routing mechanism. Software defined networking (SDN) is suitable for the purpose since it provides visibility of network resources and programmable interfaces. OpenFlow is the most recognized realization of SDN. We propose a QoS-aware routing mechanism for OpenFlow-enabled WMSNs. The mechanism consists of a framework and routing algorithms on SDN controller. The framework includes two functions: detection of link states among OpenFlow-enabled nodes and determination of flow's QoS requirements. The routing algorithms are achieved in two steps. First, the SDN controller seeks the feasible paths that satisfy QoS requirements of a flow. If there is no path which satisfies the required QoS, the path will be decided by the proposed algorithms depending on flow types: delay-sensitive, bandwidth-sensitive, and best-effort traffic. We conducted experiments on a SDN testbed to evaluate our mechanism and compared the results with conventional routing protocols. The results show that proposed routing mechanism increases the throughput by 43% for video data and reduces the delay by more than 30% for audio data.

In the environment of data explosion, how to make an effective and accurate personalized point of interest (POI) recommendation in location-based social networks (LBSNs) is a challenging and meaningful task. Fortunately, there is a lot of information that we can use. We can make recommendations by mining the rich information hidden in user check-in records. In this paper, we propose a recommend system named GFP-LORE. Specifically, we have designed a framework, which integrates various influencing factors. First, we modeled friend sign-in frequencies and POI popularity as a power-law distribution and the experiment proved that it is effective. Then, we got the influence of geographic information by modeling it according to the longitude and latitude of the user's check-in location. After that, we sorted the historical check-in records of all users according to time and then mine an overall pattern of location transfer-order pattern. Then, we combine it with each user's own unique location transfer record to get the possibility of the user going to the next POI. Finally, we synthesize the above four influence factors into a unified correlation probability rating and recommend a new location by this probability rating. We tested our system on the open real check-in data set, and the results of our simulation experiments show that the recommendation effect of our system is better than those algorithms used in the contrast test.

In mobile SCTP, a mobile terminal has two or more network interfaces and vertical handover occurs when it moves from one network to another. The delay due to the handover process and the slow-start phase of SCTP's congestion control after handover cause substantial performance degradation. If the mobile node goes back and forth frequently, excessive handovers occur and data transmission quality deteriorates. In order to provide the required level of QoS for on-going application, the frequency of handovers should be kept minimized. In this paper, we propose a transport layer handover mechanism using the mobile SCTP. We take the QoS requirements of application as the major criterion in deciding path switching. In our mechanism, the mobile node in overlapping area does not perform handover if the current network metrics satisfy the QoS requirements of on-going application. Both analytic evaluation and simulation results show that the proposed mechanism significantly improves the throughput by suppressing unnecessary handovers. Our research results can also be applied to distributed mobile sensor networks.

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Mobile Edge Computing (MEC) technology brings the unprecedented computing capacity to the edge of mobile network. It provides the cloud and end user swift high-quality services with seamless integration of mobile network and Internet. With powerful capability, virtualized network functions can be allocated to MEC. In this paper, we study QoS guaranteed multicasting routing with Network Function Virtualization (NFV) in MEC. Specifically, data should pass through a service function chain before reaching destinations along a multicast tree with minimal computational cost and meeting QoS requirements. Furthermore, to overcome the problems of traditional IP multicast and software-defined multicasting approaches, we propose an implementable multicast mechanism that delivers data along multicast tree but uses unicast sessions. We finally evaluate the performance of the proposed mechanism based on experimental simulations. The results show that our mechanism outperforms others reported in the literature.