M50 Hardware Design
M50_HD_V2.0
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Appendix A: GPRS coding schemes
Four coding schemes are used in GPRS protocol. The differences between them are shown in
Table 39.
Table 39: Description of different coding schemes
Scheme Code
rate
USF Pre-coded
USF
Radio
Block
excl.USF
and BCS
BCS
Tail
Coded
bits
Punctured
bits
Data
rate
Kb/s
CS-1
1/2
3
3
181
40
4
456
0
9.05
CS-2
2/3
3
6
268
16
4
588
132
13.4
CS-3
3/4
3
6
312
16
4
676
220
15.6
CS-4
1
3
12
428
16
-
456
-
21.4
Radio block structure of CS-1, CS-2 and CS-3 is shown as Figure 60:
Figure 59: Radio block structure of CS-1, CS-2 and CS-3
Radio block structure of CS-4 is shown as Figure 61:
Figure 60: Radio block structure of CS-4
Block
code
No coding
456 bits
USF
BCS
Radio Block
Rate 1/2 convolutional coding
Puncturing
456 bits
USF
BCS
Radio Block
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