This book is the first monographs in china.
Wireless LAN
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Role of BLE in Wearable TechnologyThe high penetration of smart phones in many mature markets, combined with the wide availability of lower cost MEMS sensors, has lead to the rise of new category of electronics known as wearable devices. A wearable device is a highly portable device that is worn or otherwise attached to the body, and is capable of measuring/capturing information via one or more sensors.
Wearable devices can be broadly classified based on the market segment they serve or the body part on which they are intended to be worn.
Most wearable devices are equipped with one or more sensor(s), a processor, storage, connectivity link (i.e., radio controller), display, and battery.
There are various communication protocols available for use in wearable, including standards like Bluetooth Classic, ZigBee, and Wi-Fi, as well as proprietary interfaces developed by silicon vendors. Standard protocols like Bluetooth classic, ZigBee, and Wi-Fi have not been designed with low power as the primary design consideration. For this reason, many OEMs chose to use a proprietary protocol focused on energy efficiency. The use of a proprietary protocol imposes many restrictions on the flexibility of these wearable products by restricting their interoperability to only devices using the same proprietary protocol.
To address the limitations, the Bluetooth Special Interest Group (SIG) has introduced Bluetooth Low Energy (BLE) specifically designed to achieve the lowest possible power for short-range communication. Just like Bluetooth classic, BLE continues to operate in 2.4 GHz ISM band with a bandwidth of 1 Mbps. Some of the salient features of BLE are: • BLE’s low data rate makes for an ideal fit for applications where only state information has to be exchanged. • The protocol is optimized to burst transmit small blocks of data at regular intervals, thus enabling the host processor to maximize the amount of time it can operate in a low-power mode when information is not being transmitted. • The protocol is optimized to reduce the time required from connection setup to data exchange to within a few mini-seconds. • Each layer of the architecture has been optimized to reduce power consumption:
• The physical layer’s modulation index is increased as compared to Bluetooth classic, thus helping reduce transmit and receive current.
• The link layer is optimized for quick re-connections, thereby reducing power.
• The controller implements various key tasks like establishing the connection and ignoring duplicate packets, thus enabling the host processor to stay in low-power modes for an extended duration. • BLE has a robust architecture similar to Bluetooth classic supporting Adaptive Frequency Hopping with a 32-bit CRC. • It supports only broadcaster mode so wearable communications does not have to undergo a connection procedure. A BLE device is not compatible with standard Bluetooth radio as it is a different technology. However, Bluetooth dual-mode devices do support both BLE and classic Bluetooth. Due to the adoption of Bluetooth Smart Ready host (dual-mode devices), BLE eliminates the need for a dongle for its operation as compared to proprietary protocols. |
News: Bluetooth Music, Color-Changing, Mesh Networking LightingBluetooth smart LED lighting, with music function, varies of color and strong networking power. Can be used in varies of fields: Bluetooth smart home mesh networking lighting, Bluetooth smart hotel mesh networking lighting, Bluetooth factory mesh networking lighting, Bluetooth hospital mesh networking lighting, Bluetooth smart school mesh networking lighting, Bluetooth agricultural mesh networking lighting, Bluetooth streetlights lighting, Bluetooth festival mesh networking lighting etc. |