WLAN
- WPS：Wi-Fi Protected Setup；
- Most modern WLANs are based on IEEE 802.11 standards and are marketed under the Wi-Fi brand name.
- Wi-Fi 4 (802.11n), Wi-Fi 5 (802.11ac) and Wi-Fi 6 / Wi-Fi 6E (802.11ax 10G).
- Wi-Fi 7 (802.11be 30G) 2022 聯(lián)發(fā)科 MediaTek Filogic。
- RouterCtrl：help regular internet users with every network and network equipment issue。
Wi-Fi Education
BLE：Bluetooth Low Energy
- Introduction to GATT: Generic ATTribute Profile. 知乎。
- Services, characteristics, and descriptors are collectively referred to as attributes, and identified by UUIDs：128 bit，通常標(biāo)識為 16 bit（2個(gè)字節(jié)），Allocated UUID、Bluetooth Assigned Numbers。例如：
0x1131 Headset - HS，0x1112 Headset - Audio Gateway (AG)，0x1131和0x1112就是為 Headset Profile兩個(gè)角色HS和AG分配的UUID。 - List of Bluetooth profiles.
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HSP @bluetooth.com: Headset Profile 1.2，2008年。
AT command set、及其 External links。 -
HRP: Heart Rate Profile 1.0，2011年。
All transactions are started by the main device(Central role), the GATT Client, which receives response from the secondary device(Peripheral role), the GATT Server.
Profile, Services and Characteristics
Heart Rate Profile 1.0 - Heart Rate Service Characteristic Discovery:
1、Heart Rate Measurement Characteristic (shall)
2、Body Sensor Location Characteristic (may)
3、Heart Rate Control Point Characteristic (may)
SmartPhone
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IMEI：International Mobile Equipment Identity。在 這里 可以查一下手機(jī)終端的型號參數(shù)，還挺準(zhǔn)。
15位：8位TAC+6位序列號+1位校驗(yàn)碼，例如：356709086591456。iPhone 8 plus 實(shí)現(xiàn) Bluetooth 5.0。 - MEID 和 IMEI 類似。手機(jī)撥號鍵入
*#06#即可顯示。 - ICCID：SIM 卡號。比如：89860316xx010yyyyyy0。共20位：89產(chǎn)業(yè)代碼，8603 表中國電信，16表年份，010表地區(qū)，0校驗(yàn)碼。
- 流暢性/卡頓：在用戶有操作的前提下平均掉幀率。只有在某一時(shí)刻發(fā)生的掉幀（跳幀）情況遠(yuǎn)遠(yuǎn)大于其他時(shí)刻，那么才界定為卡頓。界面的掉幀程度更直觀的反映出卡頓。幀率 FPS (每秒顯示幀數(shù))。12 FPS 連貫，一般電影 25 ~ 30FPS，游戲畫面體驗(yàn) 60FPS。首先反映的是播放的穩(wěn)定性。
- DROP LEVEL：frozen high middle normal best.
WLAN
WLAN 工作在 OSI 的層一和層二，即 Physical layer （PHY）and Data Link layer（MAC & LLC）。如果你熟悉 wired network，如 Ethernet，對照了解即可。
A wireless local area network (WLAN) is a wireless computer network that links two or more devices using a wireless distribution method (often spread-spectrum or OFDM radio) within a limited area such as a home, school, computer laboratory, or office building.
Wi-Fi
簡單地說，Wi-Fi 是 WLAN 的一個(gè)具體實(shí)現(xiàn)技術(shù)，基于 802.11 標(biāo)準(zhǔn)，致力于業(yè)界產(chǎn)品互操作性的測試和認(rèn)證，Wi-Fi 商標(biāo)由 Wi-Fi 聯(lián)盟擁有。追溯起來，Wi-Fi 不是什么縮寫，就是選出的一個(gè) 名字。
Wi-Fi is a trademark of Wi-Fi Alliance. It is actually not a standard and only ensures that products using this trademark can interoperate with each other. As most Wi-Fi products use the IEEE 802.11b standard, Wi-Fi usually refers to 802.11b. Wi-Fi is a new technology that uses the WLAN protocol.
Wi-Fi can provide wireless coverage in an area with a radius of up to 90 m (300 inches), while the WLAN can provide wireless coverage in an area with a radius 5 km (with antennas used). The biggest advantage of Wi-Fi is its high transmission speed (up to 11 Mbit/s). Wi-Fi is a short-distance wireless transmission technology applicable to offices and households.
Hotspot (Wi-Fi)
A hotspot is a physical location where people may obtain Internet access, typically using Wi-Fi technology, via a wireless local area network (WLAN) using a router connected to an internet service provider.
- Apple OS 7 以上，通過 Personal Hotspot 可以對外共享 3G/4G 互聯(lián)網(wǎng)連接，這是以軟件實(shí)現(xiàn)的 Wi-Fi 熱點(diǎn)（Software hotspots）。
Wi-Fi、Access Point and Hotspot
Wi-Fi is the technology. You build a wireless network based on the Wi-Fi specifications and principles.
An Access Point is a physical device which is used to offer Wi-Fi service to a small area.
A Hotspot is the area served by an access point.
So, you go to a hotspot so you can connect with an access point using Wi-Fi.
Hotspot is the where, access point is the what, Wi-Fi is the how.
Wi-Fi and Internet 示意
Residential gateway
簡單的一個(gè)應(yīng)用場景就是你家的家用網(wǎng)關(guān)，也能了解到不少知識。
