蓝牙低能耗RSSI周期性变化，在Android设备上 [英] Bluetooth-Low-Energy RSSI changes periodically on Android devices

问题描述

我注意到，在机器人收到的蓝牙低能量的信号强度在周期是变化的。
下面再$ P $图表超过两分钟，psents 1 BLE信标的RSSI值。接收Android和信标均用1米的距离是静态的。我确信，还有低干扰越好。而Android是Nexus 5的，但我不得不与其他Android设备同样的现象，在API 21.所有正在运行的我无法测试它在iOS上呢。

I noticed that the signal strength of Bluetooth Low Energy received on Androids is varying in cycles. The graph below represents the RSSI values of one BLE beacon over two minutes. The receiving Android and the beacon were both static with a distance of 1 meter. I made sure that there is as low interference as possible. The Android was a Nexus 5, but I had the same phenomenon with other Android devices, all running on API 21. I could not test it on iOS yet.

RSSI图表

您可以看到有对RSSI 3大的层次每隔15秒，如低重复 - >中 - >高级 - >低 - >中 - >高等等

You can see that there are 3 major levels for the RSSI repeating every 15 seconds, like low -> middle -> high -> low -> middle -> high etc.

我的猜测是，原因在于对Android的一面，不知道是否是因为硬件或软件的原因。

My guess is that the reason lies on the android side, not sure whether it is because of hardware or software reasons.

为什么RSSI循环一段时间？有人能解释一下吗？

Why is the RSSI cyclic over time? Can someone explain?

推荐答案

现在看了大量进入正题之后，我可能已经到了一个答案。

After reading a lot into the topic now, I might have come to an answer.

蓝牙低功耗信标使用三个不同的渠道广告，这是他们的跳频，以避免与其他2.4GHz的信号干扰的适应。这种情况发生比正常蓝牙（1600 / s）的慢得多。 - 根据我的每5秒左右的测量

Bluetooth Low Energy beacons use three different channels for advertising, which is their adaption of frequency hopping to avoid interference with other 2.4GHz signals. This happens much slower than for normal Bluetooth (1600/s) - according to my measurements around every 5 seconds.

这里更多：
<一href=\"http://www.argenox.com/bluetooth-low-energy-ble-v4-0-development/library/a-ble-advertising-primer/\" rel=\"nofollow\">http://www.argenox.com/bluetooth-low-energy-ble-v4-0-development/library/a-ble-advertising-primer/

接收到的信号强度明显依赖于频率，因此，如果频率变化到另一个频道，则RSSI是不同的。如何应对，现在是一个不同的问题。

The received signal strength depends obviously on the frequency, so if the frequency changes to another channel, the RSSI is different. How to deal with that is now a different question.

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