5G/NR - SLIV                             Home : www.sharetechnote.com

 

 

 

 

 

SLIV

 

SLIV is the Start and Length Indicator for the time domain allocation for PDSCH. One of the big difference between LTE and NR scheduling is that NR schedules not only for slot but also the symbols within the scheduled slot, whereas in LTE the schedule is done only for subframe level (not for the symbol levels within the scheduled subframe).

SLIV defines the start symbol and the number of consecutive symbols for PDSCH allocation using Single Number. Often, SLIV is considered to be very confusing because you need to figure out two quantities(start and length) from the single value.

How the single number(SLIV) can represent the two different quantity (i.e, start symbol and number of consecutive symbols) ? It is possible because SLIV is created by a specific rule as  defined in 38.214 5.1.2.1 Resource allocation in time domain as follows.

NOTE : With this formula, you can easily figure out SLIV value if you are given the start symbol and the number of symbols, but it is not that simple to figure out start and symbol length from a given SLIV.  To figure out start and length of symbols from a given SLIV value, it would be handy to use a lookup table in this page.

 

    if (L-1) <= 7 then

          SLIV = 14 x (L-1) + S

    else

          SLIV = 14 x (14-L+1) + (14-1-S)

          , where 0 < L <= 14 - S

                   S = Start Symbol Index

                   L = Number of Consecutive Symbols

 

According to the above equation, you can create a huge tables with the possible S and L values. But not all of the combinations are taken as valid.  Only the set of combinations meeting the condition in the following table is allowed.

 

< 38.214-Table 5.1.2.1-1: Valid S and L combinations >

 

< 38.214-Table 6.1.2.1-1: Valid S and L combinations >

 

 

PDSCH/PUSCH mapping type in the above table is specified in RRC message as shown below.

 

PDSCH-TimeDomainResourceAllocation ::=      SEQUENCE {

    k0                                  INTEGER (1..3)

    mappingType                         ENUMERATED {typeA, typeB},

    startSymbolAndLength                BIT STRING (SIZE (7)) // SLIV

}

 

PUSCH-TimeDomainResourceAllocation ::=  SEQUENCE {

    k2                                  INTEGER (0..7)                          

    mappingType                         ENUMERATED {typeA, typeB},

    startSymbolAndLength                BIT STRING (SIZE (7)) // SLIV

}

 

 

Applying the equation shown above and  38.214-Table 5.1.2.1-1, I have created a big table as below.

 

Following is the SLIV values that I calculated according to the formnula described above. You can use SLIV value as a key value to find out a unique pair of (S, L) in a look-up table. (NOTE : If you clicked on the linked page, you will get an example of PDSCH scheduling for a specific SLIV that I created using Matlab 5G Toolbox)

 

S

L

L-1

Last
Symbol

SLIV

Valid Mapping Type
(Normal CP)
PDSCH

Valid Mapping Type
(Normal CP)
PUSCH

0

1

0

0

0

Type B

2

1

1

14

Type B

Type B

3

2

2

28

Type A

Type B

4

3

3

42

Type A,Type B

Type A,Type B

5

4

4

56

Type A

Type A,Type B

6

5

5

70

Type A

Type A,Type B

7

6

6

84

Type A,Type B

Type A,Type B

8

7

7

98

Type A

Type A,Type B

9

8

8

97

Type A

Type A,Type B

10

9

9

83

Type A

Type A,Type B

11

10

10

69

Type A

Type A,Type B

12

11

11

55

Type A

Type A,Type B

13

12

12

41

Type A

Type A,Type B

14

13

13

27

Type A

Type A,Type B

1

1

0

1

1

Type B

2

1

2

15

TypeB

Type B

3

2

3

29

Type A

Type B

4

3

4

43

Type A,Type B

Type B

5

4

5

57

Type A

Type B

6

5

6

71

Type A

Type B

7

6

7

85

Type A,Type B

Type B

8

7

8

99

Type A

Type B

9

8

9

96

Type A

Type B

10

9

10

82

Type A

Type B

11

10

11

68

Type A

Type B

12

11

12

54

Type A

Type B

13

12

13

40

Type A

Type B

2

1

0

2

2

Type B

2

1

3

16

Type B

Type B

3

2

4

30

Type A

Type B

4

3

5

44

Type A,Type B

Type B

5

4

6

58

Type A

Type B

6

5

7

72

Type A

Type B

7

6

8

86

Type A,Type B

Type B

8

7

9

100

Type A

Type B

9

8

10

95

Type A

Type B

10

9

11

81

Type A

Type B

11

10

12

67

Type A

Type B

12

11

13

53

Type A

Type B

3

1

0

3

3

Type B

2

1

4

17

Type B

Type B

3

2

5

31

Type A

Type B

4

3

6

45

Type A,Type B

Type B

5

4

7

59

Type A

Type B

6

5

8

73

Type A

Type B

7

6

9

87

Type A,Type B

Type B

8

7

10

101

Type A

Type B

9

8

11

94

Type A

Type B

10

9

12

80

Type A

Type B

11

10

13

66

Type A

Type B

4

1

0

4

4

Type B

2

1

5

18

TypeB

Type B

3

2

6

32

Type B

4

3

7

46

Type B

Type B

5

4

8

60

Type B

6

5

9

74

Type B

7

6

10

88

Type B

Type B

8

7

11

102

Type B

9

8

12

93

Type B

10

9

13

79

Type B

5

1

0

5

5

Type B

2

1

6

19

TypeB

Type B

3

2

7

33

Type B

4

3

8

47

Type B

Type B

5

4

9

61

Type B

6

5

10

75

Type B

7

6

11

89

Type B

Type B

8

7

12

103

Type B

9

8

13

92

Type B

6

1

0

6

6

Type B

2

1

7

20

TypeB

Type B

3

2

8

34

Type B

4

3

9

48

Type B

Type B

5

4

10

62

Type B

6

5

11

76

Type B

7

6

12

90

Type B

Type B

8

7

13

104

Type B

7

1

0

7

7

Type B

2

1

8

21

Type B

Type B

3

2

9

35

Type B

4

3

10

49

Type B

Type B

5

4

11

63

Type B

6

5

12

77

Type B

7

6

13

91

Type B

Type B

8

1

0

8

8

Type B

2

1

9

22

Type B

Type B

3

2

10

36

Type B

4

3

11

50

Type B

Type B

5

4

12

64

Type B

6

5

13

78

Type B

9

1

0

9

9

Type B

2

1

10

23

Type B

Type B

3

2

11

37

Type B

4

3

12

51

Type B

Type B

5

4

13

65

Type B

10

1

0

10

10

Type B

2

1

11

24

Type B

Type B

3

2

12

38

Type B

4

3

13

52

Type B

Type B

11

1

0

11

11

Type B

2

1

12

25

Type B

Type B

3

2

13

39

Type B

12

1

0

12

12

Type B

2

1

13

26

Type B

Type B

13

1

0

13

13

Type B

 

 

Reference

 

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