M3-Cast: A Novel Multicast Scheme in Multi-Channel and Multi-Rate WiFi Direct Networks for Public Safety

WiFi direct (WD) network is of significant interest during public safety scenarios due to its easy, quick, and efficient implementation. WD provides device to device communication using the MAC and PHY layers specifications of 802.11 standards, which facilitate multiple communications channels and a number of transmission rates to cope with the requirements and challenges of emerging applications in public safety and disaster management. Although they achieve substantial benefits in terms of high throughput, it creates a performance anomaly problem, wherein the selection of a particular communication channel and transmission rate can significantly affect the performance of a wireless communication system. This paper investigates the problem of selecting the most favorable channel and rate for a multicast communication system in the context of public safety using a WD 802.11 network. To this end, M
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-Cast protocol is proposed, which refers to a novel multi-rate multi-channel multicast scheme. M
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-Cast not only chooses the most favorable communication channel and transmission rate, but also considers the implementation details of the underlying WD technology, thereby optimizing the overall system performance. M
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-Cast is formulated analytically and evaluated by a complete system level simulation. The detailed results and the analysis considers a number of performance metrics, such as bit error rate, multicast capacity, and system throughput under different multiple input multiple output configurations, channel bandwidths, and various network radii. Consequently, the simulation and analytical results show that M
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-Cast protocol outperforms the standard multicast protocol of WD by almost twofold in terms of system throughput.