ViewsonRemainingIssuesonSCHDesign..doc

3GPP TSG RAN WG1 49 R1-072189 Kobe, Japan, 26 – 30 March, 2007 Source: Texas Instruments Title: Views on Remaining Issues on SCH Design Agenda Item: 7.2 Document for: Discussion and Decision Introduction A number of aspects of cell search and SC design were resolved in RAN1#48bis, e.g. non-repetitive P-SCH structure with ZC sequences, S-SCH design based on a combination of 2 codes. In this contribution, the additional unresolved details related to the SCH design are discussed in relation to the working assumptions that were agreed upon in RAN1#48bis. The following aspects are covered in this contribution: Detection of cell-specific information other than cell ID P-SCH design S-SCH design Detection of Cell-Specific Information According to the working assumption [1]: Cell ID group is detected in step 2 (via the S-SCH): 170 hypotheses Cell ID within the group can be detected in step 1 (via the P-SCH) or step 3 (via the 2D-RS orthogonal codes): 3 hypotheses Frame timing is detected in step 2 (via the S-SCH): 2 hypotheses It is assumed that the CP size of the SCH sub-frame is blindly detected. It was also decided that the hopping indicator is removed. There are 2 possibilities regarding the detection of the CCPCH transmit diversity indication (N is the number of hypotheses in the S-SCH): N=1: CCPCH uses transparent transmit diversity N=2: CCPCH uses non-transparent transmit diversity Our preference is N=2 since we prefer to use the same Tx diversity scheme for CCPCH, PDCCH, and PDSCH. The reasoning is as follows: Non-transparent transmit diversity schemes (SFBC for 2-Tx, SFBC-FSTD or SFBC-PSD for 4-Tx) perform better than transparent schemes (e.g. CDD) for CCPCH (see, e.g. [2-5]). Although the S-SCH does not accommodate N=3, reliable blind detection of the TX diversity scheme is possible via decoding the CCPCH twice with both hypotheses (2 or 4 antennas). Each hypothesis is associated with the transmit diversity sc