In the EEA2 option for encryption in LTE the AES-128 algorithm is mechanized. There, the nonce used in the CTR Mode is a 128-bit value. The first 64-bits are covered by a COUNTER, a BEARER, a DIRECTION, and a LENGTH parameter. LENGTH parameter is supposed to control the output of the KEYSTREAM length (not changing the bits themselves).
However, I was not able to find anywhere a useful description of how this parameter actually works. Available documentation gives detailed descriptions of the COUNTER, BEARER, and DIRECTION parameters (these amount to 38-bits) and the rest 26-bits are set to 0 (the remaining 64-bits are set to 0 and then incremented).
Does anyone know what this LENGTH parameter does and how it works? It seems to me it has no particular reason to be mentioned...