Page 778 - 5G Basics - Core Network Aspects

2 Transport aspects

Figure 10-12 – Combination of a pair of 1-bit constellations to
build a 2-bit constellation

Figure 10-13 shows the constellation for the case b  3.

5 6
+3

7 0
+1

-3 -1 +1 +3
-1
2 1
3
4 -3

Figure 10-13 – Constellation labels for b  3

For odd values of b that are greater than three, the two MSBs of X and the two MSBs of Y shall be
determined by the five MSBs of the b bits (vb–1 vb–2 ... v1 v0). Let c = (b+1)/2, then X and Y shall have the
two's complement binary representations (Xc Xc–1 vb–4 vb–6...v3 v1 1) and (Yc Yc–1 vb–5 vb–7 ...v2 v0 1), where Xc
and Yc are the sign bits of X and Y respectively. The relationship between Xc, Xc–1, Yc, Yc–1, and (vb–1 vb–2...vb–5)
shall be as shown in Table 10-4.

Table 10-4 – Determining the top two bits of X and Y

vb–1 vb–2...vb–5 Xc Xc–1 Yc Yc–1 vb–1 vb–2...vb–5 Xc Xc–1 Yc Yc–1
0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 1 0 0
0 0 0 0 1 0 0 0 0 1 0 0 0 1 0 1 0 0
0 0 0 1 0 0 0 0 0 1 0 0 1 0 1 0 0 0
0 0 0 1 1 0 0 0 0 1 0 0 1 1 1 0 0 0

0 0 1 0 0 0 0 1 1 1 0 1 0 0 0 0 0 1
0 0 1 0 1 0 0 1 1 1 0 1 0 1 0 0 1 0
0 0 1 1 0 0 0 1 1 1 0 1 1 0 0 0 0 1
0 0 1 1 1 0 0 1 1 1 0 1 1 1 0 0 1 0
0 1 0 0 0 1 1 0 0 1 1 0 0 0 1 1 0 1

768