Advances in multimedia services over emerging wireless networks
The advances of emerging wireless networks and new multimedia technologies have inspired more diversified multimedia applications and services. It can be seen that the emerging wireless networks will make possible a new generation of multimedia services and applications. This special issue mainly aims to congregate the state of the art and future oriented research contributions that focus on the applications, architectures, and protocols developed for emerging wireless multimedia services. Basically, this issue tends to encompass theoretical and practical research on the recent advances in multimedia services over emerging wireless networks. Among several high quality papers, only four were included in this special issue. A summary of papers is as follows. "Exploiting Multiple Description Coding for Intermediate Recovery in Wireless Mesh Networks" by Pradipta De, Nilanjan Banerjee, and Swades De, proposes a solution to combine Multiple Description Coding (MDC) and meshed multipath routing in such a way that multiple descriptions are sent over different paths in the network and are merged at the intermediate nodes for possible recovery of lost or corrupted descriptions by using the link error information (De et al. 2014) This approach reduces the possibility of error propagation, thereby improving the overall image/video quality at the destination. The authors have investigated an optimum spatial interleaving based MDC scheme that maximizes the intermediate recovery possibility for a given recovery filter design in order to achieve high gain in terms of peak signal to noise ratio (PSNR) They have also explored the choice of an optimum number of descriptions at an intermediate merging point that maximizes the PSNR gain. In the paper "Peer assisted Video On demand Streaming System in Practical WiFi based Mobile Opportunistic Networks" Hayoung Yoon, Hayoung Yoon, JongWon Kim, and Robert Hsieh pointed out challenges in on demand streaming services over mobile WiFi enabled devices including smart phones, tablets, e book viewers and personal media players (Yoon et al. 2014) They have enhanced their previous work onMobile Opportunistic Video on demand (MOVi) by exploiting the use of cooperative content sharing concept in gaining performance advantages and proposed an improved scheduling algorithm, which incorporates H hop blocking and opportunistic download skipping schemes. Furthermore, they have analyzed the scalability of the extended MOVi system by extensive simulations and several experiments with prototype implementation over OMF (Control and Management Framework) enabled wireless network testbeds. "Amulti channel architecture for IPv6 enabled wireless sensor and actuator networks featuring PnP support" authored by Paulo A. Neves, Joel J. Rodrigues, Min Chen, and Athanasios V. Vasilakos, presents a novel multi channel architecture for sensor data gathering and actuation, featuring Plug and Play like functionality for node attachment and operation, IPv6 at the node level, and dedicated communication semantic protocols the ZenSens system architecture (Neves et al. 2014) The architecture incorporates sensor/actuator nodes, personal computer application (SenseLab) mobile application (SenseLab mobile) and World Wide Web access (WebSensor) presenting the user with a complete sensing and actuation solution. The proposed architecture is validated through a series of experiments on real hardware, using a test bed with TelosB motes running ContikiOS. Quality of Service (QoS) consideration is vitally important while adapting multimedia content through user preferences. In the paper "Multimedia
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