In this paper we identify the most prominent problems of wireless multimedia networking and present several state-of-the-art solutions with a focus on energy efficiency. Three key problems in networked wireless multimedia systems are 1) the need to maintain a minimum quality of service over time-varying channels, 2) to operate with limited energy resources, and 3) to operate in a heterogeneous environment. We identify two main principles to solve these problems. The first principle is that energy efficiency should involve all layers of the system. Second, Quality of Service is an essential mechanism for mobile multimedia systems not only to give users an adequate level of service, but also as a tool to achieve an energy-efficient system. Due to the dynamic wireless environment, adaptability of the system will be a key issue in achieving this. Keywords -- energy efficiency, wireless networking, mobile computing, quality of service. 1 Introduction Advances in technology enabl...

Data aggregation protocols are implemented in resource constrained wireless sensor networks to eliminate redundant data transmission for improving bandwidth utilization and energyefficiency of sensor nodes. This paper presents a secure differential data aggregation (SDDA) protocol for wireless cluster-based sensor networks. SDDA prevents redundant data transmission from sensor nodes to cluster-heads, whereas conventional data aggregation techniques eliminate redundant data at cluster-heads. SDDA first implements a sleep protocol which puts all but one sensor node that sense the same data to sleep, and then awake sensor nodes generate pattern codes to represent the main characteristics of sensed data. Cluster-heads first determine distinct pattern codes and then request only one sensor node for each distinct pattern code to transmit data to base station. Hence, cluster-heads perform data aggregation based on pattern codes. While sensors transmit their raw data to cluster-heads in conventional data aggregation algorithms, in SDDA, raw data sensed by sensor nodes are compared with reference data values and then only the difference data are transmitted. Reference data are taken as the average value of a number of previous readings. The fact that SDDA does not require cluster-heads to examine the sensed data for data aggregation helps implementing secure data transmission because the encrypted data of sensor nodes need not be decrypted by cluster-heads along the transmission path. By taking advantage of deployment estimation of sensor nodes, SDDA establishes secure connectivity among sensor nodes without performing any online key distribution. Performance of SDDA is evaluated in terms of bandwidth efficiency and energy consumption. Simulation results show that SDDA is more e...

Programming Sensor Networks currently is a subtle task not because of enormous amount of code but due to inherent limitations of embedded hardware like the power, memory, network bandwidth and clock speed. In addition, there are very few programming abstractions and standards available which lead to close coupling between the application code and the embedded OS requiring understanding of low-level primitives during implementation. A Middleware can provide glue code between the applications and the heterogeneity of devices by providing optimized set of services for autonomously managing the resources and functionality of wireless nodes in a distributed wireless sensor network. This paper presents an autonomous middleware framework for low power distributed wireless sensor networks that support adaptive sensor functionality, context aware communications, clustering, quality of service and faulttolerance. Finally an application on how to use the autonomous middleware is illustrated on the Envelope

Development of wireless technology enabled mobile networking at any time, anyplace. In the not too remote future, many everyday objects such as portable devices and appliances will be equipped with small wireless network interfaces and tied to digital networks. Utilizing such nodes and vast number of networked sensors scattered in every place will provide unprecedented flexible services. We call this kind of network High-Density Networks. In high-density networks, ad-hoc routing protocol is a key technology because it is essential to send and receive data packets among all nodes. In this paper, we present SARAH (Stable Adaptive Routing in Ad-hoc Networks of Heterogeneous Nodes), which is a routing protocol for high-density network s. SARAH can cope with node diversity and can provide stable connection between nodes. The performance of SARAH in terms of stable route construction is shown by computer simulation..

Abstract—Most wireless sensor network (WSN) proposals are unrelated to multimedia and other smart home infrastructures. This paper combines these issues and presents a solution where the Kilavi sensor network platform can be used as middleware to provide information for ZUMA. Kilavi is a centralized protocol designed for communication between high capacity management point and low capacity sensor nodes in building environment. ZUMA is a centralized future smart-home platform that interconnects all kinds devices in the home environment. This paper mainly focuses on sensor network operation issues. The discussion is on the benefits that the centralized architecture can provide in typical sensor network operations that are node discovery, routing and data dissemination, power control, and security. To support the discussion, the paper gives numbers that illustrate the benefits that centralization has over typical decentralized WSN solutions in home environment.

Wireless network is composed of sensor nodes. Sensor nodes are deployed in harsh physical environment to gather data and deliver the data to the remote base station. Since sensor nodes have energy source they have limited computation capability. The sensed information is difficult to operate the sensor network for a long period of time in an energy efficiency manner. The data collection problem is described in a round of communication; each sensor node has a packet to be sent to the distant base station. If each node transmits its sensed data directly to the base station then it will deplete its power quickly. The LEACH protocol is a chic solution to this data collection problem, where a small number of clusters are formed to fuse data and then sending to the base station. It chooses the cluster head to transmit the base station. A factor of 8 perfection is attained compared to the direct