ABSTRACT
Wireless sensor networks (WSNs) have unique characteristics, such as self-conguration, low cost, easy deployment, and distributed sensing capacity. As a result, the eld of WSNs has enjoyed tremendous research attention over the past decade. Traditional WSNs are often deployed in hard-to-reach areas for prolonged durations to report various real-time scalar data such as temperature, humidity, and light intensity. Usually such networks are operated for a long time without any human intervention. Successful WSN deployment [1-3] has gained a new and promising dimension among the research community with the introduction of multimedia data such as image and video. As a result, applications can get highdimensional data with increased accuracy both in event detection and periodic monitoring. Furthermore, for cost-benet analysis,
recent trends indicate that multiple applications with varied QoS requirements can be eciently deployed in a single network [4,5]. Consequently, WMSNs have received a great deal of research attention in recent years. Traditional protocols for WSN cannot cope with MWSN gracefully because they were designed to handle scalar data from a single application. In this chapter, we present a novel QoS-aware packet delivery technique to support high data rates and delay bound requirements for WMSNs. e promising pace of technological growth has led to the design of sensor nodes with the capability of sensing the environment and producing multimedia data. However, because multimedia trac contains images, video, audio, and scalar data, each merits a dierent metric. To accommodate a high data rate, designing an ecient routing protocol is of primary interest. e signicance of such a protocol becomes clear with a few challenging and motivating facts. First, research challenges found in Ref. [6] state that existing data rates of about 40 and 250 kbit/s supported by the MICA2 and MICAz [7] motes are not geared to support multimedia trac. Instead of improving the hardware and thus increasing cost, an alternate approach is to more eciently utilize the available bandwidth. By using multiple channels in a spatially overlapped manner, the existing bandwidth can be leveraged to support multimedia applications. Second, the use of multipath technology has two clear advantages: (1) the load may be balanced so as not to overwhelm the limited buers at the intermediate sensor nodes and (2) one path condition may not permit a high data rate for the entire duration of the event being monitored. By allowing multiple paths, the eective data rate of each path gets reduced and the application can be supported. is chapter presents a protocol that targets the application of WMSNs where sensors produce multimedia content from the deployed area to deal with both critical and general data. Applications may include critical condition monitoring and security surveillance tasks such as monitoring a volcano explosion, toxic gases, or a forest re; military applications such as sniper or enemy detection; and civil applications such as the location of survivors for rescue services. Once a node detects an important event, fast and reliable delivery is required; late or failed delivery may cause disaster. In a real-time application
such as multimedia streaming, delivered data can become useless in only a few milliseconds.
