How extension items are encoded in unaligned Per Sequence?

asked 2018-03-22 12:18:14 +0000


Currently I am working on LPP protocol encoding. It is unaligned Basic PER protocol. In a Sequence I am able to encode root items with out any issues. But not able to encode extension items.

Ex: OTDOA-ProvideCapabilities ::= SEQUENCE { otdoa-Mode BIT STRING { ue-assisted (0), ue-assisted-NB-r14 (1) } (SIZE (1..8)), ..., supportedBandListEUTRA SEQUENCE (SIZE (1..maxBands)) OF SupportedBandEUTRA OPTIONAL }

according x691 spec extension part will have 1 bit set 0, then number of optional elements are encoded in next 6 bits. then follows Preamble. The rest is encoded as open type.

After Preamble what should be followed? If Length has to be updated then is it in terms of Octet or bits? If it's octet then what if we have not encoded complete byte. Example 12 bits?

I appreciate any help on this. Thanks in advance

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