Bluetooth, and especially Bluetooth-Low Energy take a different approach to theenergy problems of scanning outlined before. Originally designed as ultra-lowpower technology, Bluetooth radio in a smartphone can stay operational the entireday without changing its power consumption profile significantly, while in laptopsand tablets it is barely noticeable compared to the screen, CPU, and GPU. So,Bluetooth devices can afford to stay awake and broadcast some information aroundthem for discovery purposes. However, Bluetooth itself can not be utilized for theD2D file transfers or HD video streaming it just does not have the bitrate for it. Inaddition, Bluetooth lacks the necessary flexibility in terms of accepting connec-tions while establishing new ones, thus suffering from the same problem as WiFi itis too reliant on simple access point paradigm to implement topologies necessaryfor D2D. Indeed, scatternets (networks where a Bluetooth master device is also aslave in a different network) are standardized, it is still difficult for a single deviceto perform both scanning and establishing of the connection at once.Combined with WFD, Bluetooth provides an interesting solution for D2Dcommunications, as it can greatly reduce the cost of scanning for services, whileletting WiFi’s high bitrate sine when the proximity with service is confirmed.However, such hybrid system requires two short-range radios to stay online, whilealso interfering between each other. Therefore, when WiFi is used for data,
Bluetooth link can not be active, and if a single connection is started proximity
detection, as well as interaction with conventional Bluetooth peripherals, become
difficult.
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