Page 95 - From GMS to LTE

General Packet Radio Service (GPRS) and EDGE 81

White bits are guessed,
as they were not transmitted
1/3 coder

1. Transmission

Decoder now has two of three coded bits
In further transmission attempts
different bits are sent
2. Transmission

Decoder now has all three original bits

3. Transmission

Figure 2.8 MCS‐9 convolutional coding and incremental redundancy.

Table 2.4 Re‐segmentation of EDGE blocks using a different MCS.

MCS Family Speed (kbit/s) Re‐segmentation
MCS‐9 A 59.2 (2 × 29.2) 2 × MCS‐6
MCS‐8 A 54.4 (2 × 29.2 + padding) 2 × MCS‐6 (+ padding)
MCS‐6 A 29.2 (2 × 14.8) 2 × MCS‐3
MCS‐3 A 14.8 –
MCS‐7 B 44.8 (2 × 22.4) 2 × MCS‐5
MCS‐5 B 22.4 (2 × 11.2) 2 × MCS‐2
MCS‐2 B 11.2 –
MCS‐4 C 17.6 2 × MCS‐1
MCS‐1 C 8.8 –

burst, it has been decided to decrease the block size for MCS‐7, MCS‐8 and MCS‐9 to
fit in two bursts instead of four. This reduces the number of bits that need to be retrans-
mitted after a block error has occurred and thus helps the system to recover more
quickly. The block length reduction is especially useful if frequency hopping is used in
the system. When frequency hopping is used, every burst is sent on a different