Page 740 - 5G Basics - Core Network Aspects

2 Transport aspects

NOTE – In the formulae above:
TBUDGET determines the index of the last symbol position in the logical frame that may be utilized for transmission of
a data symbol (as per Note 1 in Table 9-1). In any logical frame, except those containing a sync symbol, the index of
this symbol position is equal to TBUDGET+TA − 1 if TBUDGET is larger than TTR, otherwise it is equal to TBUDGET − 1.
The maximum number of symbols containing DTU bytes (RMC symbol and data symbols) in any logical frame that
does not include a sync symbol is equal to TBUDGET.
The maximum number of symbols containing DTU bytes (RMC symbol and data symbols) in a logical frame that
contains a sync symbol is equal to TBUDGET if TBUDGET + TA is less than the total number of symbol positions in a
logical frame, otherwise it is equal to TBUDGET − 1.
The settings of the TTR, TA and TBUDGET values for a particular logical frame are independent of a sync symbol being
present in the logical frame.

9.6 RMC
9.6.1 RMC frame format

The RMC primitives comprise the acknowledgement data and management/control data formatted into an
RMC frame (see clause 9.6.4). The RMC framer shall format the RMC message into an RMC frame, as
presented in Figure 9-5. The RMC frame shall include an integer number of bytes. The total size of the RMC
frame shall be as defined in clause 9.6.3. Padding shall be appended to the end of the last command of the
RMC message to align with the total size of the RMC frame. The padding bytes shall be all 0016.

Figure 9-5 – RMC frame format

The first byte of an RMC frame is the first byte of the first command of the RMC message (see Figure 9-7)
contained in this RMC frame.

9.6.2 RMC scrambler
The scrambling algorithm shall be as represented by the equation below and as illustrated in Figure 9-6; the
output bit of RMC data x(n) at the sample time n shall be:
x(n) = m(n)+ x (n – 18) + x (n – 23),

where m(n) is the input bit of the RMC at sample time n. The arithmetic in this clause shall be performed in
the Galois Field GF(2).

Figure 9-6 – RMC scrambler

The scrambler state [x(n – 1) : x(n – 23)], shall be reset to the CNTLF of the logical frame in which the RMC
frame is transmitted before inputting the first bit of each RMC frame. Bit 0 (LSB) of the CNTLF shall be used
to initialize the scrambler delay element x (n – 23) and bit 15 (MSB) of the CNTLF shall be used to initialize
the delay element x(n-8). Delay elements [x(n-1) : x(n-7)] shall be reset to zero.

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