Protocol-Stack-in-Wifi-Chips

Protocol Stack in Wi-Fi Devices

WiFi设备中的软件层次结构图如下:

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Figure 1: Protocol Stack in Wi-Fi Devices

Full MAC & Soft MAC

Wi-Fi芯片可以根据是否包含MLME功能分为 Full MACSoft MAC

What is the advantage of having (or not having) the MLME in the Wi-Fi chipset?

Ans: MLME is MAC Sublayer Management Entity and takes care of various management procedures like Assocation, Authentication etc. 芯片中如果包含了MLME功能,则主芯片可以将一些特定的功能(如漫游功 能)交给Wi-Fi芯片。另一方面,也会导致Wi-Fi芯片的开销增加(如需要更多 的内存、更多的处理工作)。 Full MAC 芯片适用电池驱动的设备,而 Soft MAC 则适用于直接供电的设备。

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Figure 2: Full MAC

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Figure 3: Soft MAC