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System Information Block (SIB) Transmission Setup

LTE FDD Signal Studio can support SIB transmission on DL-SCH with user defined SIB contents. This topic discusses how to setup up the SIB transmission measurement. Refer to 3GPP TS 36.321 and 3GPP TS 36.331.

This topic contains the following sections:

• Overview of SIB Preparation of Transmission

• Assumptions for this Example

• Configure the Signal Studio Software

Overview of SIB Preparation of Transmission

• System Information Block (SIB): There are 13 SIBs (SIB1 to SIB13) in the above 3GPP standard specification. Each SIB contains specific information. SIB1 means System Information Block Type1.

• System Information (SI): The System Information message is used to convey one or more System Information Blocks.

• Assign SI message to SIBs combinations are flexibly defined in SIB1 contents.

• SIB can be transmitted with following DCI combinations.

  DCI Format	Resource Allocation Type
  1A	Type 2, Localized
  1A	Type 2, Distributed
  1C	Type2, Distributed

• SIB1 is a special SIB which has a fixed schedule with a periodicity of 80 ms and repetitions made within 80 ms. The first transmission of SIB1 is scheduled in subframe #5 of the radio frames for which the SFN mod 8 = 0, and repetitions are scheduled in subframe #5 of all other radio frames for which SFN mod 2 = 0.

• The SI messages are transmitted within periodically occurring time domain windows (referred to as SI-windows) using dynamic scheduling. Each SI message is associated with a SI-window and the SI-windows of different SI messages do not overlap. That is, within one SI-window only the corresponding SI is transmitted. The length of the SI-window is common for all SI messages, and is configurable. Within the SI-window, the corresponding SI message can be transmitted a number of times in any subframe other than the Multicast Broadcast Multimedia Services Single Frequency Network (MBSFN) subframes and subframe #5 of radio frames for which SFN mod 2 = 0. The UE acquires the detailed time-domain scheduling and other information (e.g. frequency-domain scheduling and used transport format) from decoding SI-RNTI on PDCCH (Refer to 3GPP TS 36.321).

• SIB1 configures the SI-window length and the transmission periodicity for the SI messages.

• SIB1 RV Index = ceiling (3/2*k) modulo 4, where k = (SFN/2) modulo 4.

• SIB RV Index = ceiling (3/2*k) modulo 4, where k depends on the type of system information messages, k=i modulo 4, i =0,1,…, n_s^w–1, where i denotes the subframe number within the SI window n_s^w.

Assumptions for this SIB Transmission Example:

• System Bandwidth = 10 MHz (50RB), SIB1 and SI1 (SIB2 and SIB3) message.

• SIB1 is assigned to DL-SCH1

• SI1 (SIB2 and SIB3) is assigned to DL-SCH2

• SI-Window = 20 (ms)

• User has generated their own SIB contents

Configure the Signal Studio Software:

• Setting up Signal Studio (General)

• Setting up SIB1

• Setting up SI1

Setting up Signal Studio (General)

1. Starting with the default setup for the N7624B Signal Studio software.

2. Delete the existing carrier.

3. Click Add Carrier and add Advanced LTE FDD Downlink Carrier.

4. At the Carrier node, in the 1. General area, click Channel Configuration and click on the down arrow to select Full filled QPSK 10MHz (50RB). (Or in the Downlink node, you can click the Predefined Config. button to access the same channel configurations.)

5. Click Waveform Generation Length and set to 80 ms.

Setting up SIB1

1. In the Channel Setup node, select DL-SCH1 and then change RNTI Type to SI-RNTI.

2. Click Transmission Configuration Length and set to 80 ms.

3. Click Transmission Configuration to open the DL-SCH1 Tx Sequence window.

4. Click Column Preset button and select Select all "State" to OFF.

5. Click State to set the necessary state of the Subframe #5 of even number frame to on for the SIB transmission. (For this SIB1 transmission case, SIB1 transmission has to satisfy 3GPP section 5.2.1.2 of 36.331.)

   For this SIB Transmission example use the following settings:

   Sequence #	Frame #:	Subframe #	State
   6	0	5	on
   26	2	5	on
   46	4	5	on
   66	6	5	on

6. Click Column Preset and select Set all MCS#1 to..., then enter 4 to satisfy TB #1 ≤ TB Size #1.

7. Click Column Preset and select Set all N_1A_PRB to 2 (default).

8. Set each Subframe RV #1 (RV Index) using the values below. This example is for SIB1 transmission.

   Sequence #	Frame #	Subframe #	RV #1 (RV Index) Value
   6	0	5	ceiling (3/2*(SFN/2) modulo 4) modulo 4 = 0
   26	2	5	2
   46	4	5	3
   66	6	5	1

   Refer to 3GPP section 5.3.1 36.321.

9. Click OK to close DL-SCH1 Tx Sequence window.

10. Click in the Data #1 cell to open the Data Source Selection window and select User Defined Bits. Then enter your own generated SIB contents by importing or direct entry into the bit field. Click OK when finished.

Setting up SI1 (SIB2 and SIB3)

1. In the Channel Setup node, select DL-SCH2.

2. In General Settings, set State to On for SI1 (SIB2 and SIB3) message transmission.

3. In the General Settings, click the RNTI Type drop down and select SI-RNTI.

4. Click Transmission Configuration Length and set to 80 ms.

5. Click Transmission Configuration to open the DL-SCH2 Tx Sequence window.

6. Click Column Preset and click Select all "State" to OFF.

7. Set the required State of the Subframes to on for SI1 (for this example, SIB2 and SIB3) transmission. Click Sequence 12, Frame 1, Subframe #1, State check box.

   For this example of the SI1 message transmission case, it is assumed that the transmission on Sequence #12, Frame #1, Subframe #1 State = on. Transmission Sequence 12, Frame 1, Subframe #1 is just an example, you can select any subframe to transmit that satisfies the 3GPP standard. Refer to section 5.2.1.2 36.331.

8. Select MCS Index (MCS #1) to satisfy the desire TB Size ≤ setting TB Size.

   Example: where 30 bytes (240 bits) = TB Size

   1. Set MCS #1 (MCS Index) to 8.

   2. Set N_1A_PRB to 2 (default).

   3. Verify that TB Size now displays 256.

9. Set each Subframe RV #1 (RV Index).

   For this example:

   Sequence #12, Frame #1, Subframe #1 RV #1(RV Index)= ceiling (3/2*(11 modulo 4)) modulo 4 = 1.

   Refer to 3GPP section 5.3.1 36.321.

10. Click OK to close the DL-SCH2 Tx Sequence window.

11. Generate user-defined SIB contents (customer supplied) and insert the data into Data #1 on DL-SCH2 as User Defined Bits.

    Example where TB Size (User-Defined SIB Contents) < setting TB Size:

    • User-generated SIB contents is 240 bits

    • Setting TB Size is 256 bits

      1. Set the data for Data #1 of DL-SCH2 as User Defined Bits.

      2. Append 16 zero bit to user defined SIB contents.

12. Click OK to close Data Source Selection window.