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System Information Block (SIB) Transmission Setup

LTE TDD Signal Studio supports SIB transmission on DL-SCH with user defined SIB contents. This topic provides general information on system information blocks and an example setup. Refer to 3GPP TS 36.321 and 3GPP TS 36.331 for more details.

This topic contains the following sections:

• System Information Transmission Overview

• Example Setup

System Information Transmission Overview

• There are 13 System Information Blocks (SIBs), SIB1 to SIB13, defined in the 3 GPP standards characterized by the type of information that they include.

• The System Information Block Type 1 (SIB1) is unique in that it uses 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.

• System information blocks other than System Information Block Type 1 are carried in SI messages; there may be multiple SI messages transmitted with the same periodicity.

• Mapping of SIBs to SI messages is flexibly configurable by scheduling information included in System Information Block Type 1.

• SIBs can be transmitted with following DCI combinations.

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

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

• The SI messages are transmitted within periodically occurring time domain windows (referred to as SI-windows) using dynamic scheduling.

• Different SIs have different non-overlapping SI-windows. 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, uplink subframes in TDD, 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 the SI-RNTI on PDCCH (Refer to 3GPP TS 36.321).

• 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.

Example Setup

Assumptions:

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

• 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

Configuring the Signal Studio Software

• Setting up Signal Studio (General)

• Setting up SIB1

• Setting up SI1

Setting up Signal Studio (General)

1. Start with the default setup for the N7625C Signal Studio software.

2. Delete the existing carrier.

3. Click Add Carrier and add Advanced LTE TDD Carrier.

4. At the Downlink node, click the Predefined Config. button and select Full filled QPSK 10MHz (50RB).

5. At the Carrier node, set Waveform Generation Length to 8 frames (80 ms) and Uplink Downlink Configuration to 1.

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 8 frames (80 ms).

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

4. Click Column Preset button and Set 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 MCS Index 0 to..., then enter 4 to satisfy Transmit Block Size ≤ Block Size 0.

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

8. Set each Subframe RV Index 0using the values below. This example is for SIB1 transmission:

   Sequence #	Frame #	Subframe #	RV Index 0 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-SCH Tx Sequence window.

10. Click in the Data 0 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. Append zero bit (“0”) to make data length equal to the TB size set in step 6. Click OK when finished.

Setting up SI1 (SIB2 and SIB3)

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

2. In the 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 8 frames (80 ms).

5. In Transmissions Configuration to open the DL-SCH Tx Sequence window.

6. Click Column Preset and select Set 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 15, Frame 1, Subframe #4, State check box.

   For this example of the SI1 message transmission, it is assumed that the transmission on Sequence 15, Frame 1, Subframe #4 State = on. Transmission Sequence 15, Frame 1, Subframe #4 is just an example; you can select any subframe that satisfies the 3GPP standard. Refer to section 5.2.1.2 36.331.

8. Select MCS Index 0 to satisfy the desired TB Transport Block Size ≤ setting Transport Block Size.  

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

   1. Set MCS Index 0 to 8.

   2. Set N_1A_PRB to 2 (default).

   3. Verify that Block Size 0 now displays 256.

9. Set each Subframe RV Index 0.

   For this example:

   Sequence #12, Frame #1, Subframe #1, RV 0 = ceiling (3/2*(11 modulo 4)) modulo 4 = 1.

   Refer to 3GPP TS 36.321), section 5.3.1.

10. Click OK to close he DL-SCH Tx Sequence window.

11. Generate user-defined SIB contents (customer supplied) and insert the data into Data 0 on DL-SCH2 as User Defined Bits.

12. Click OK to close the Data Source Selection window.