Hi Vicamo:
 Thanks for your comment!!

For LTE signal, rxlev | rsrp | rssnr (at least one) are necessary for reporting LTE signal strength. (see [1])
(If we got invalid LTE signal strength, the value shoule be 99, 0x7FFFFFFF, 0x7FFFFFFF for rxlev, rsrp and rssnr which is defined in ril.h)

In short, there should be *no* "no arguments" case, and, for the error handling of no arguments was done at #1628.

Please share with me your thought if any.
Thanks!!
Shawn

[1] https://github.com/android/platform_frameworks_base/blob/master/telephony/java/android/telephony/SignalStrength.java#L740