很多小伙伴都搞不清楚RSSI、ED、LQI、CCA等概念，那我們就看看802.15.4標(biāo)準(zhǔn)文檔中的定義吧。

802.15.4標(biāo)準(zhǔn)文檔：
《IEEE Std 802.15.4?-2015, IEEE Standard for Low-Rate Wireless Networks》
CSDN下載地址（1積分）：https://download.csdn.net/download/gjh13/10453909
或者官網(wǎng)去下載，免費(fèi)的。

10.2.5、Receiver ED
The receiver ED measurement is intended for use by a network layer as part of a channel selection algorithm. It is an estimate of the received signal power within the bandwidth of the channel. No attempt is made to identify or decode signals on the channel. The ED measurement time, to average over, shall be equal to 8 symbol periods.

The ED result shall be reported to the next higher layer using MLME-SCAN.confirm. The minimum ED value (zero) shall indicate received power less than 10 dB above the lowest specified receiver sensitivity, in dBm, for the PHY. The range of received power spanned by the ED values shall be at least 40 dB. Within this range, the mapping from the received power in decibels to ED value shall be linear with an accuracy of ± 6 dB.

10.2.6 Link quality indicator (LQI)
The LQI measurement is a characterization of the strength and/or quality of a received packet. The measurement may be implemented using receiver ED, a signal-to-noise ratio estimation, or a combination of these methods. The use of the LQI result by the network or application layers is not specified in this standard.

The LQI measurement shall be performed for each received packet. The minimum and maximum LQI values (0x00 and 0xff) should be associated with the lowest and highest quality compliant signals detectable by the receiver, and LQI values in between should be uniformly distributed between these two limits. At least eight unique values of LQI shall be used.

總結(jié)

以上是生活随笔為你收集整理的Receiver ED、Link quality indicator (LQI)、Clear channel assessment (CCA)究竟是什么？802.15.4标准的全部?jī)?nèi)容，希望文章能夠幫你解決所遇到的問題。

如果覺得生活随笔網(wǎng)站內(nèi)容還不錯(cuò)，歡迎將生活随笔推薦給好友。