Search

Recently, the femtocell has been proposed to offload the traffic from the macrocell. In femto/macrocell networks, a location management should be supported to keep track of the current location of a mobile node (MN). Since the conventional mobility management scheme of femto/macrocell networks does not consider mobility pattern of the MN, unnecessary location updates occur. Specifically, when the MN moves along the contour of the femtocell coverage, the MN frequently executes location update which causes high location update cost. To address this problem, we propose a mobility-aware location management (MALM) scheme that the MN does not execute location update in femtocells where the MN stops by while conducting location update at the specific locations expected that the MN stays for a long time. Then, to optimize MALM, a Markov decision process (MDP) problem is formulated and the optimal policy is determined. Evaluation results demonstrate that MALM with the optimal policy can reduce the number of location updates and provide sufficient offloading effect.

For multimedia streaming in mobile environments, video bitrate should be carefully determined and different channel quality and pricing in heterogeneous wireless networks (e.g., cellular and WiFi networks) need to be considered. In this work, we propose a new bitrate adaptation (BA) technique called mobility-aware dynamic adaptive streaming over HTTP (MDASH), in which a cellular data usage is minimized through a Markov Decision Process (MDP) framework. Preliminary simulation results are shown that MDASH can reduce 23% of the cellular data usage without any playback interruptions while minimizing the temporal variations in the video quality.

Contents oriented network (CON) is a new network paradigm to redesign Internet for providing enhanced user experience in contents delivery services. In this paper, we introduce a cross layer approach to reduce the contents access latency when CON is deployed in mobile environments. The proposed scheme can be easily implemented by means of IEEE 802.21 media independent handover (MIH) and can reduce the contents access latency significantly.

In home networks, a variety of smart devices are connected to a WiFi access point (AP) and the oversized buffer of the AP causes high latency/delay jitter and reduced network throughput (known as the bufferbloat problem). To mitigate this problem, appropriate active queue management (AQM) algorithms should be implemented at the AP. In this paper, we conduct extensive simulation study on the performance of CoDel, which is one of the most effective AQMs. Simulation results demonstrate that CoDel with carefully configured parameters can provide comparable throughput and shorter round-trip time compared to the tail drop queue management algorithm.

Recently, a data packet forwarding scheme between evolved node Bs (eNBs) in long-term evolution (LTE)/LTE-advanced (LTE-A) networks has been proposed to reduce the signaling overhead and delay incurred in the data path switching scheme. However, the conventional data packet forwarding scheme suffers from the increased delay when the length of the data packet forwarding chain is inappropriately long. To attain the optimal handover performance in LTE/LTE-A networks, we propose an optimized and distributed data packet forwarding scheme where an optimal length of the forwarding chain is obtained by a Markov decision process (MDP). Numerical results demonstrate that the proposed scheme achieves the optimal and adaptive performance in diverse network environments.

Recently distributed mobility management (DMM) in ID/locator separation architectures has been widely investigated to provide load balanced and scalable mobility services. However, it has drawbacks in terms of the network mobility (NEMO) support since IDs cannot be aggregated. In this paper, a novel network mobility support protocol is proposed in a distributed ID/locator separation architecture. In the proposed protocol, a mobile router sends an aggregate location update message on the behalf of multiple mobile nodes and thus the signaling overhead and delay can be significantly reduced.