DSL Advances

6.7. CORE SHDSL Framer (PMS-TC)

The structure of the SHDSL core frame is based on the superframe structure of HDSL2 as described in Chapter 4. This section briefly describes the SHDSL core frame per Recommendation G.991.2.

Figure 6.19 shows the core SHDSL physical layer superframe. The nominal frame period (T_frame) is 6 msec. There are four blocks for payload data bits identified as PB1–PB4. Because the line bit rate is variable, the number of bits in an SHDSL superframe will depend on the payload bit rate.

Figure 6.19. SHDSL core frame structure.

There are also five subblocks allocated for overhead bits labeled as OH1–OH4 and block SB (stuff ...