4 General

37.4663GPPIuant interface: Application partRelease 17TS

4.1 Procedure specification principles

The principle for specifying the procedure logic is to specify the functional behaviour of the RET antenna control unit and TMA Subunits exactly and completely. The RAN Node functional behaviour is left unspecified.

The following specification principles have been applied for the procedure text in clause 6:

– The procedure text discriminates between:

1) Functionality which "shall" be executed

The procedure text indicates that the receiving node "shall" perform a certain function Y under a certain condition. If the receiving node supports procedure X but cannot perform functionality Y requested in the REQUEST message of a Class 1 EP, the receiving node shall respond with the message used to report unsuccessful outcome for this procedure, containing an appropriate cause value.

2) Functionality which "shall, if supported" be executed

The procedure text indicates that the receiving node "shall, if supported," perform a certain function Y under a certain condition. If the receiving node supports procedure X, but does not support functionality Y, the receiving node shall proceed with the execution of the EP, possibly informing the requesting node about the not supported functionality.

4.2 Forwards and backwards compatibility

The forwards and backwards compatibility of all versions of the protocol shall be assured by a mechanism in which all current and further messages will not be changed in the future. These parts can always be decoded regardless of the standard version.

New functionalities are added into the specification by introducing new procedures and thus the existing messages are not changed in the future.

4.3 Multi-antenna units

The RETAP elementary procedures are split into a single-antenna oriented part, a multi-antenna oriented part and a common part for both device types in order to support RET units controlling single- or multi-antenna devices. The RET unit responds, upon request, the number of antennas it controls. All multi-antenna oriented elementary procedures include a parameter stating which antenna the elementary procedure addresses. Antennas are numbered 1 and upwards.

4.4 Integer representation

Multi-octet integer values are transmitted in little endian order. Signed integers are represented as 2-complement values.

4.5 TMA Subunits

TMA subunits shall be numbered starting with 1 and proceeding upwards. The error message format for TMA procedures follows that of multiple RET devices.