دانلود رایگان مقاله روش چند کانالی و شناختی رادیویی برای شبکه حسگر بی سیم

Abstract

In traditional wireless sensor networks communicating on a single channel data throughput measured at the sink is constrained by the radio capability, interference, and collisions. Enabling a multi-channel transmission is a potential solution to alleviate the above problem and improve the network performance. Many approaches have been proposed to exploit multiple channels on unlicensed frequencies. The advanced development of cognitive radio enables wireless sensor networks to use vacant licensed channels. Cognitive radio wireless sensor networks enable a dynamic channel selection with the restriction of releasing a channel when a primary user is present. When nodes are set on different channels, coordination has to be carefully designed to ensure a successful transmission. This issue is mainly addressed at the MAC and network layers. In this paper, we provide an intensive survey on various aspects of traditional and cognitive multi-channel wireless sensor networks. Different approaches are categorized based on their underlying topology. Major developments are discussed and drawbacks of the existing approaches are identified.

5. Conclusions

Utilizing multiple channels in WSNs can alleviate interferences and reduce collisions, thus enhancing the network capacity. Existing approaches incorporate channel assignment to MAC protocols, routing protocols, or address it as a separate topology control problem. In this paper, we categorized and described WSN multichannel approaches proposed recently in the research literature. We further extended our discussion to the CRSN which is a newly emerging research area. CRSN is a multi-channel WSN utilizing licensed frequencies. The opportunistic access to licensed frequencies enabled by cognitive radio technology brings appealing bene- fits to WSNs as well as new design challenges due to the unique characteristics of cognitive radios. The approaches discussed in this paper are summarized in Table 2.