RE: Thread Network Diagnostics Cluster always reports very low LQI

Susheel Nuguru — Thu, 26 Feb 2026 09:12:35 GMT

Sorry for the late reply but yes that is what it is . Link quality is derived from link margin and then bucketed to 0-3 with hysteresis. This is aøso documented here

  /**
     * Returns the current one-way link quality value. The link quality value is a number 0-3.
     *
     * The link quality is calculated by comparing the current link margin with a set of thresholds (per Thread spec).
     * More specifically, link margin > 20 dB gives link quality 3, link margin > 10 dB gives link quality 2,
     * link margin > 2 dB gives link quality 1, and link margin below or equal to 2 dB yields link quality of 0.
     *
     * In order to ensure that a link margin near the boundary of two different link quality values does not cause
     * frequent changes, a hysteresis of 2 dB is applied when determining the link quality. For example, the average
     * link margin must be at least 12 dB to change a quality 1 link to a quality 2 link.
     *
     * @returns The current link quality value (value 0-3 as per Thread specification).
     *
     */
    LinkQuality GetLinkQuality(void) const { return mLinkQuality; }

RE: Thread Network Diagnostics Cluster always reports very low LQI

Tom McGuinness — Wed, 25 Feb 2026 14:41:37 GMT

I think I have the answer to this. The OpenThread library uses a value of 0 to 3 for quality. 0 being the worst and 3 being the best.

Can you confirm this for me?