1. Explanation of draft TP IP Radio Network Development Department
on Cell Search
IP Radio Network Development Department
NTT DoCoMo, Inc.
March 8, 2006

2. Purpose of Draft Text Proposal on
Cell Search

3. Purpose of Draft Text Proposal on Cell Search
To reach common agreed views on E-UTRA cell search, we propose draft text proposal (TP) on cell search as the starting point of discussion
Through discussion on cell search, we would like to reach common views as much as possible at the coming RAN1#44bis, in order to accelerate the SI discussion of LTE.
To achieve agreements as much as possible among RAN1 members, we tried to make contents of the text proposal be general statements by including several options for items, which it seems difficult to align at the moment

4. Purpose of Draft Text Proposal on Cell Search
Following the purpose in the previous slide, we made draft TP on cell search based on the contributions, which were submitted to RAN1 meetings by #44 in February, 2006
The contributions referred in draft TP are listed in the next slide

5. References (1)
3GPP, R , Nokia, “EUTRA Cell Search for initial synchronization and neighbor cell identification”
3GPP, R , NTT DoCoMo, Ericsson, Fujitsu, Mitsubishi Electric, Motorola, NEC, Panasonic, Sharp, Siemens, Toshiba Corporation, “Text Proposal on Cell Search in E-UTRA (1): Radio Frame Structure“
3GPP, R , NTT DoCoMo, Ericsson, Fujitsu, Mitsubishi Electric, NEC, Nokia, Panasonic, Sharp, Siemens, Toshiba Corporation, “Text Proposal on Cell Search in E-UTRA (2): Sub-frame Structure“
3GPP, R , NTT DoCoMo, Ericsson, Fujitsu, Mitsubishi Electric, Motorola, NEC, Panasonic, Sharp, Toshiba Corporation, “Text Proposal on Cell Search in E-UTRA (3): Frequency Domain Structure and Basic Cell Search Procedure“
3GPP, R , NTT DoCoMo, NEC, Sharp, “SCH Structure and Cell Search Method for E-UTRA Downlink”
3GPP, R , NTT DoCoMo, Fujitsu, Mitsubishi Electric, NEC, Sharp, “Cell Search Method for MIMO Node B in E-UTRA Downlink”
3GPP, R , NTT DoCoMo, Fujitsu, NEC, Panasonic, Toshiba Corporation, “Cell Search Method for Connected and Idle Mode in E-UTRA Downlink”
3GPP, R , Huawei, “Non-hierarchical cell search for E-UTRA”
3GPP, R , Samsung, “Cell search and related physical channel mapping”
3GPP, R , Samsung, “Text proposal on cell search and related physical channel mapping”
3GPP, R , Siemens, “Considerations on E-UTRA Cell Search and Initial Access”
3GPP, R , InterDigital, “Considerations on SCH for Cell Search in E-UTRA”
3GPP, R , Motorola, “Cell Search and Initial Acquisition for EUTRA”

6. References (2) 3GPP, R1-060426, ETRI, “Cell Search Scheme for EUTRA”
3GPP, R , ETRI, “Text Proposal for Cell Search and SCH Structure”
3GPP, R , Texas Instruments, “Aspects and Design of DL SYNC channel (SCH) for E-UTRA”
3GPP, R , Texas Instruments, “Timing and cell-specific info detection in cell search procedure for E-UTRA“
3GPP, R , NTT DoCoMo, NEC, Toshiba Corporation, “Comparison of SCH Structures for Timing Detection in E-UTRA Downlink”
3GPP, R , TD Tech, “Downlink cell search design for E-UTRA TDD”
3GPP, R , Qualcomm Europe, “DL Acquisition for E-UTRA”
3GPP, R , ZTE, “Cell Search Scheme for Evolved UTRA”
３GPP, R CATT, RITT, “Cell Search procedure of EUTRA TDD system for the initial synchronization”
3GPP, R , Fujitsu, “Channel Design and Long CP Sub-frame Structure for Initial Cell Search”
3GPP, R , IPWireless, “Downlink Synchronisation Signal Placement”
3GPP, R , Nortel, “Cell search / Synchronization channel design for E-UTRA“
3GPP, R , Nortel, “TP for Cell search / Synchronization channel design for E-UTRA”

7. Outlines of Sections on Cell Search

8. Explanation of Each Section of Draft TP (1)
Purposes of SCH, Reference signal, and BCH are specified
OFDM symbol (SCH symbol) timing detection by using SCH
(Note that most companies agreed the purpose)
Radio frame timing (= 10 msec) detection using either of following channels
Option 1: SCH (e.g. DoCoMo, Ericsson, Huawei, Motorola, Nortel, Qualcomm, Samsung, TI, ZTE)
Option 2: BCH (e.g. Nokia, Siemens)
Cell ID or Cell ID group detection using either of following channels
Option 1: SCH (e.g. Ericsson, Huawei, Motorola, Nortel, TI, Samsung, ZTE)
Option 2: Reference signal (e.g. CATT, Nokia, RITT, Siemens)
Option 3: SCH for cell ID group detection and Reference signal for final cell ID detection (e.g. DoCoMo, ETRI, Motorola, Nortel, Qualcomm, Samsung, Siemens, TI)
Note that the usage of cell ID grouping is FFS during study item
Continued to next slide

9. Explanation of Each Section of Draft TP (2)
Continued from previous slide
Lists of other system information that are detected during cell search using either of SCH, reference signal and BCH
System bandwidth
Cell configuration (number of cells within same Node B, etc)
MIMO antenna configuration (number of transmitter antennas)
BCH bandwidth if multiple transmission bandwidths of BCH are defined (detected by either of SCH or reference symbol)
CP length
Note that we don’t identify concrete channel for each information in the statements

10. Explanation of Each Section of Draft TP (3)
Structures of SCH and BCH in time domain are specified
Only the positions of the SCH and BCH transmission timing are specified. Note that detailed SCH sequence structure is not specified since there are too many proposals at the moment.
Number of SCH and BCH transmissions during one radio frame
Option 1: One time (e.g. Motorola, Qualcomm, Samsung, ZTE)
Option 2: Multiple times (e.g. CATT, DoCoMo, Ericsson, ETRI, Motorola, Nokia, Nortel, RITT, Siemens, TI, ZTE)
Note that the number of transmission for SCH and BCH can be different.
SCH position within sub-frame
Option 1: Last OFDM symbol to make constant SCH transmission timing regardless of CP length (e.g. DoCoMo, Motorola, Nokia, Nortel, Siemens, TI, ZTE)
Option 2: Any OFDM symbol(s) with restriction of mandatory usage of same CP length for sub-frame with SCH (e.g. CATT, Ericsson, Motorola, RITT)

11. Explanation of Each Section of Draft TP (4)
Structures of SCH and BCH in frequency domain are specified
SCH is transmitted from the center of entire transmission bandwidth using constant 1.25 MHz bandwidth regardless of entire transmission bandwidth, in order to support cell search in scalable system bandwidth (we consider most of companies agreed the method)
BCH is also transmitted from the center of entire transmission bandwidth. But, there is two bandwidth options at this stage.
Option 1: 1.25 MHz for simplicity (e.g. CATT, Ericsson, ETRI, Motorola, Nokia, Nortel, Qualcomm, RITT)
Option 2: 5 MHz to increase the frequency diversity effect when the system bandwidth is equal to or wider than 5 MHz (e.g. DoCoMo, Nortel, Qualcomm)
Necessity of cell ID detection using only the central portion of the system bandwidth (i.e., the part of the bandwidth containing the SCH) is specified for fast cell search regardless of Node B’s system bandwidth
Detailed frequency domain SCH structure is not described since we think it is difficult to align one SCH structure now (i.e., the statements don’t identify auto-correlation based timing detection or cross-correlation based (replica based) timing detection)

12. Explanation of Each Section of Draft TP (5)
Transmit diversity methods for SCH and BCH are specified
Possible candidates are listed.
For SCH, following transmit diversity methods that don’t need a priori knowledge of the number of the transmission antennas are the candidates for evaluation.
Option 1: Time switched transmit diversity (TSTD)
Option 2: Delay diversity including cyclic delay diversity (CDD)
For BCH, following transmit diversity methods are the candidates for evaluation. Note that since BCH is decoded after SCH and reference signal identification, more complex transmit diversity requiring a priori knowledge of the number of the transmission antennas can be applicable.
Option 3: Block code-based transmit diversity