Real Time

PRACH Wizard (Basic LTE-A FDD)

Parameter Descriptions

 

Configure PRACH Preamble

Detail Parameters

System Bandwidth

Preamble Format

Resource Block Offset

PRACH Configuration Index

Auto-configuration

Logical Root Sequence Index

Waveform Generation Length

Cyclic Shift Set (High speed flag)

 

Ncs Configuration

 

Ncs value

 

Preamble Index

 

Physical Root Sequence Index

 

Cyclic Shift v

 

Increase Time Offset

Additional Detail Parameter Descriptions

These additional parameters are displayed when Auto-configuration is set to PRACH Test Preamble (36.141).

Additional Detail Parameters

Increase Time Offset

Time Offset Base State

Time Offset Base Value

System Bandwidth

Choice: 1.4 MHz (6RB) | 3 MHz (15RB) | 5 MHz (25RB) | 10 MHz (50RB) | 15 MHz (75RB) | 20 MHz (100RB)

Default: 5 MHz (25RB)

Double-click or use the drop-down menu to set the system bandwidth and number of Resource Blocks (RB).

Resource Block Offset

Range: 0 to maximum number of RB in the System Bandwidth - 6.

Default: 0

Enter the number of resource blocks by which to offset the PRACH preamble.

System Bandwidth

Resource Block Offset Range

Resource Block Offset Default Value

1.4 MHz

0

0

3 MHz

0 to 9

0

5 MHz

0 to 19

0

10 MHz

0 to 44

0

15 MHz

0 to 69

0

20 MHz

0 to 94

0

Auto-configuration

Choice: RA Configuration | PRACH Test Preambles (36.141)

Default: RA Configuration

Double-click or use the drop-down menu to set Auto-configuration.

Where Auto-configuration = RA configuration, the value of Waveform Generation Length is automatically set by the software based on PRACH Configuration Index parameter.

Where Auto-configuration = PRACH Test Preamble (36.141), the wizard configures PRACH Test Preambles based on 3GPP TS 36.141 and without Cyclic Shift v. In this case, you must set the Preamble Index to satisfy Cyclic Shift v as defined in 36.141 on setting the PRACH Test Preambles (refer to tables below).

Example: Auto-configuration = PRACH Test Preamble (36.141),Cyclic Shift Set = Normal Mode, and Burst (Preamble) Format = 0, so Preamble Index should be set to 32 to satisfy Cyclic Shift v = 32 (refer to 34.141 and tables below).

Test Preambles for Normal Mode

Burst Format

Ncs value

Logical Root Sequence Index

Cycle Shift v

0

13

22

32

1

167

22

2

2

167

22

0

3

0

22

0

4

10

0

0

Test Preambles for High Speed Mode

Burst Format

Ncs value

Logical Root Sequence Index

Cycle Shift v

0

15

384

0

1

202

384

0

2

202

384

0

3

237

384

0

Waveform Generation Length

This parameter is read only and the value is automatically set by the software based on PRACH Configuration Index.

Preamble Format 

The software sets the Preamble Format based on the PRACH Configuration Index as shown in the table for that parameter.

Preamble Format

PRACH Cyclic Prefix Length (Tcp)

PRACH Sequence Length (Tseq)

PRACH Length (Tcp + Tseq)

0

3168 x Ts = 0.103125 ms

24576 x Ts = 0.8 ms

0.903.125 ms

1

21024 x Ts = 0.684375 ms

24576 x Ts = 0.8 ms

1.484375 ms

2

6240 x Ts = 0.203125 ms

2 x 24576 x Ts = 1.6 ms

1.803125 ms

3

21024 x Ts = 0.684375 ms

2 x 24576 x Ts = 1.6 ms

2.284375 ms

PRACH Configuration Index

Range: 0 to 63

Default: 14

Enter a value for the PRACH Configuration Index. The software configures the PRACH bursts according to the following table when you click OK.

Index numbers 30, 46, 60, 61, and 62 are not assigned, and are not available for input.

PRACH Configuration index

Preamble Format

System Frame Number

Subframe Number

0

0

Even

1

1

0

Even

4

2

0

Even

7

3

0

Any

1

4

0

Any

4

5

0

Any

7

6

0

Any

1, 6

7

0

Any

2, 7

8

0

Any

3, 8

9

0

Any

1, 4, 7

10

0

Any

2, 5, 8

11

0

Any

3, 6, 9

12

0

Any

0, 2, 4, 6, 8

13

0

Any

1, 3, 5, 7, 9

14

0

Any

0, 1, 2, 3, 4, 5, 6, 7, 8, 9

15

0

Even

9

16

1

Even

1

17

1

Even

4

18

1

Even

7

19

1

Any

1

20

1

Any

4

21

1

Any

7

22

1

Any

1, 6

23

1

Any

2, 7

24

1

Any

3, 8

25

1

Any

1, 4, 7

26

1

Any

2, 5, 8

27

1

Any

3, 6, 9

28

1

Any

0, 2, 4, 6, 8

29

1

Any

1, 3, 5, 7. 9

30

N/A

N/A

N/A

31

1

Even

9

32

2

Even

1

33

2

Even

4

34

2

Even

7

35

2

Any

1

36

2

Any

4

37

2

Any

7

38

2

Any

1, 6

39

2

Any

2, 7

40

2

Any

3, 8

41

2

Any

1, 4, 7

42

2

Any

2, 5, 8

43

2

Any

3, 6, 9

44

2

Any

0, 2, 4, 6, 8

45

2

Any

1, 3, 5, 7. 9

46

N/A

N/A

N/A

47

2

Even

9

48

3

Even

1

49

3

Even

4

50

3

Even

7

51

3

Any

1

52

3

Any

4

53

3

Any

7

54

3

Any

1, 6

55

3

Any

2, 7

56

3

Any

3, 8

57

3

Any

1, 4, 7

58

3

Any

2, 5, 8

59

3

Any

3, 6, 9

60

N/A

N/A

N/A

61

N/A

N/A

N/A

62

N/A

N/A

N/A

63

3

Even

9

Logical Root Sequence Index 

Range: 0 to 837

Default: 0

Enter a value for the logical root sequence index. (See 3GPP TS 36.211.) This parameter is read-only when Auto-configuration is set to On.

The Logical Root Sequence Index is the value of RACH_ROOT_SEQUENCE which is the logical index for the Zadoff-Chu sequence used for PRACH preamble generation. There is a relationship between the Logical Root Sequence Index and the Physical Root Sequence Index given by Root Zadoff-Chu sequence order table and preamble format.

In the case where preambles corresponding to Preamble Index cannot be generated from a single root Zadoff-Chu sequence, Logical Root Sequence Index is incremented until corresponding Preamble sequences are found.

That incremented Logical Root Sequence Index is displayed in the Logical Root Sequence Index (Incremented) field.

Physical Root Sequence Index, Cyclic Shift v and Incremented Logical Root Sequence Index are automatically changed on GUI based on Cyclic Shift Set, Ncs Configuration, Logical Root Sequence Index and Preamble Index.

Logical Root Sequence Index (Incremented)

Range:

0 to 837 for Format 0 to 3

Default: 0

Displays a value for the incremented logical root sequence index. Refer to 3GPP TS 36.211.

In the case where preambles corresponding to Preamble Index cannot be generated from a single root Zadoff-Chu sequence, Logical Root Sequence Index is incremented until corresponding Preamble sequences are found.

That incremented Logical Root Sequence Index is displayed in the Logical Root Sequence Index (Incremented) field.

Physical Root Sequence Index, Cyclic Shift v and Incremented Logical Root Sequence Index are automatically changed on GUI based on Cyclic Shift Set, Ncs Configuration, Logical Root Sequence Index and Preamble Index.

Cyclic Shift Set (High Speed Flag)

Choice: Unrestricted Sets | Restricted Sets

Default: Unrestricted Sets

Double-click or use the drop-down menu to set the cyclic shift restriction method. (See 3GPP TS 36.211.)

The Unrestricted Set and Restricted Set value for each Ncs configuration is shown in the following table:

Ncs Configuration

Unrestricted Set Value

Restricted Set Value

0

0

15

1

13

18

2

15

22

3

18

26

4

22

32

5

26

38

6

32

46

7

38

55

8

46

68

9

59

82

10

76

100

11

93

128

12

119

158

13

167

202

14

279

237

15

419

-

Ncs Configuration

Range:

0 to 15 (Unrestricted) for Format 0 to 3

0 to 14 (Restricted) for Format 0 to 3

Default: 0

When Auto-configuration is set to RA Configuration, enter a value for the number of cycle shifts (Ncs) configuration for preamble generation.

Ncs value is determined by Ncs configuration, Cyclic Shift Set, and Preamble format.

The corresponding Unrestricted Sets values and Restricted Sets values are shown in the table for Cyclic Shift Set.

When Auto-configuration is set to PRACH Test Preambles (36.141), this parameter is read-only.

In the case preambles corresponding to Preamble Index cannot be generated from a single root Zadoff-Chu sequence, Logical Root Sequence Index is incremented until corresponding Preamble sequences are found.

That incremented Logical Root Sequence Index is displayed on Logical Root Sequence Index (Incremented) parameter.

Physical Root Sequence Index, Cyclic Shift v, and Incremented Logical Root Sequence Index are automatically changed on the PRACH Wizard based on Cyclic Shift Set, Ncs Configuration, Logical Root Sequence Index, and Preamble Index.

See 3GPP TS 36.211 and 26.141 for more information.

Ncs value

The software sets this value based on the Ncs Configuration setting.

Preamble Index 

Range: 0 to 63

Default: 0

Enter a value for the preamble index. (See 3GPP TS 36.211.)

When the Auto-configuration parameter is set to PRACH Test Preamble (36.141),you must set the Preamble Index to satisfy Cyclic Shift v as defined in 3GPP 36.141 (PRACH Test Preambles test).

Example: Auto-configuration = PRACH Test Preamble (3GPP TS 36.141),Cyclic Shift Set = Normal Mode, and Preamble Format = 0, so Preamble Index should be set to 32 to satisfy Cyclic Shift v = 32 (refer to 34.141 A.6).

Test preambles for Normal Mode
Burst Format Ncs value Logical Root Sequence Index Cycle Shift v
0 13 22 32
1 167 22 2
2 167 22 0
3 0 22 0
4 10 0 0

 

Test preambles for High Speed Mode
Burst Format Ncs value Logical Root Sequence Index Cycle Shift v
0 15 384 0
1 202 384 0
2 202 384 0
3 237 384 0

Refer to Preamble Index-related information in TS36.212 5.3.3.1.3, TS36.321 5.1, and TS36.331 6.3.2.

Physical Root Sequence Index

This parameter is read only and the value is automatically set by the software based on Logical Root Sequence Index and the Preamble Index.

In the case where preambles corresponding to Preamble Index cannot be generated from a single root Zadoff-Chu sequence, Logical Root Sequence Index is incremented until corresponding Preamble sequences are found.

That incremented Logical Root Sequence Index is displayed in the Logical Root Sequence Index (Incremented) field.

Physical Root Sequence Index, Cyclic Shift v and Incremented Logical Root Sequence Index are automatically changed on GUI based on Cyclic Shift Set, Ncs Configuration, Logical Root Sequence Index and Preamble Index.

Cyclic Shift v

This parameter is read only and the value is automatically set by the software based on Logical Root Sequence Index , Preamble Index, Ncs Configuration, and Cyclic Shift Set. Refer to 34.141 A.6.

In the case where preambles corresponding to Preamble Index cannot be generated from a single root Zadoff-Chu sequence, Logical Root Sequence Index is incremented until corresponding Preamble sequences are found.

That incremented Logical Root Sequence Index is displayed in the Logical Root Sequence Index (Incremented) field.

Physical Root Sequence Index, Cyclic Shift v and Incremented Logical Root Sequence Index are automatically changed on GUI based on Cyclic Shift Set, Ncs Configuration, Logical Root Sequence Index and Preamble Index.

Test preambles for Normal Mode
Burst Format Ncs value Logical Root Sequence Index Cycle Shift v
0 13 22 32
1 167 22 2
2 167 22 0
3 0 22 0
4 10 0 0

 

Test preambles for High Speed Mode
Burst Format Ncs value Logical Root Sequence Index Cycle Shift v
0 15 384 0
1 202 384 0
2 202 384 0
3 237 384 0

Refer to Preamble Index-related information in TS36.212 5.3.3.1.3, TS36.321 5.1, and TS36.331 6.3.2.

Increase Time Offset

Choice: On | Off

Default: On

Double-click or use the drop-down menu to turn the Increase Time Offset on or off.

When the Increase Time Offset is turned on, the Preamble Time Offset in each preamble is increased by adding in each step a value of 0.1 (us).

This parameter is visible when the Auto-configuration is set to PRACH Test Preamble (36.141). Otherwise it’s hidden.

When this parameter is off or the Auto-configuration is set to RA Configuration, the Preamble Time Offset in each preamble is set to zero.

See 3GPP TS 36.141 for more information.

Time Offset Base State

Choice: On | Off

Default: On

When the Auto-configuration is PRACH Test Preambles (36.141), double-click or use the drop-down menu to turn the Time Offset Base State on or off. Otherwise it’s hidden.

When the Time Offset Base State is on, the Timing Offset in the component carrier node is set to the Time Offset Base Value. Otherwise it's not set.

Time Offset Base Value

Choice: On | Off

Default: On

When the Auto-Configuration is PRACH Test Preambles (36.141), displays the Time Offset Base Value. Otherwise it’s hidden.

When the Time Offset Base State is on, the Timing Offset in the component carrier node is set to the Time Offset Base Value. Otherwise it's not set.

The Time Offset Base Value depends on the Preamble Format and Cyclic Shift Set (High-speed flag).

See 3GPP TS 36.211 and 36.141 for more information.