Cell search method, forward link frame transmission method, apparatus using the same and forward link frame structure

• US 7,969,964 B2
• Filed: 07/25/2007
• Issued: 06/28/2011
• Est. Priority Date: 07/25/2006
• Status: Active Grant

• Current Assignee: Electronics and Telecommunications Research Institute
• Original Assignee: Electronics and Telecommunications Research Institute
• Inventors: Kim, Il-Gyu, Park, Hyeong-Geun, Ko, Young-Jo, Chang, Kapseok, YI, Hyoseok, Kim, Young-Hoon, Bang, Seung-Chan
• Primary Examiner(s): AJIBADE AKONAI, OLUMIDE
• Application Number:
  US12/162,237
• Publication Number:
  US 20090232125A1
• Time in Patent Office: 1,434 Days
• Field of Search: 455/502, 455/515, 455/524, 455/525, 370/328, 370/329, 370/342, 370/350, 370/503, 370/508, 370/509, 370/510, 370/512, 370/514, 370/520, 370/208, 370/209, 370/324, 370/506, 370/511, 370/513
• US Class Current: 370/350
• CPC Class Codes: H04J 11/0069 Cell search, i.e. determining cell identity [cell-ID] design of multiplexing codes H04J13/00; processing access restriction or access information H04W48/16; discovery of network devices for network data management H04W8/005; sounding signals for channel estimation H04L25/0226; structure of reference signals in multicarrier modulation systems H04L27/2613; frame, time or carrier synchronisation in multicarrier modulation systems H04L27/2655
• CPC Class Codes: H04J 11/0093 Neighbour cell search
• CPC Class Codes: H04L 27/2613 Structure of the reference signals
• CPC Class Codes: H04L 27/2655 Synchronisation arrangements
• CPC Class Codes: H04L 27/2675 Pilot or known symbols
• CPC Class Codes: H04L 5/0037 Inter-user or inter-terminal allocation
• CPC Class Codes: H04L 5/005 of common pilots, i.e. pilots destined for multiple users or terminals
• CPC Class Codes: H04L 5/0053 Allocation of signaling, i.e. of overhead other than pilot signals
• CPC Class Codes: H04W 36/0061 of neighbour cell information
• CPC Class Codes: H04W 36/08 Reselecting an access point
• CPC Class Codes: H04W 56/00 Synchronisation arrangements
• CPC Class Codes: H04W 56/001 Synchronization between nodes

Abstract

In a cellular system in which OFDM is used, a forward link synchronization channel, a common pilot channel structure, an initial cell searching method of a mobile station, and an adjacent cell searching method for handover are required.

A method of transmitting a forward synchronization signal in a wireless communication system according to the present invention includes generating a frame comprised of a plurality of sync blocks; and transmitting the frame through a forward link, wherein the frame comprises primary synchronization channel sequences which provide timing information of the sync blocks and a plurality of secondary synchronization channel sequences which provide timing information of the frame, wherein a cell identifier is specified by a combination of the primary synchronization channel sequence and a hopping code word specified by the plurality of the secondary synchronization channel sequences. Therefore, the cell searching time can be efficiently reduced in an OFDM system.

Claims

1. A method of generating a forward link frame in a communication system in which a plurality of cells are grouped into a plurality of cell groups, and each cell group includes at least two cells, the method comprising:

generating secondary synchronization signals for identifying a cell group;

generating a primary synchronization signal for identifying a cell in the cell group corresponding to the secondary synchronization signals; and

generating the forward link frame using the secondary synchronization signals and the primary synchronization signal,

wherein the forward link frame comprises a plurality of symbols in a time domain,

the secondary synchronization signals are disposed on at least two symbols, respectively, and

the secondary synchronization signals disposed on the different symbols are different sequences from each other.

2. The method of claim 1, wherein each cell belongs to only one of the plurality of cell groups.

3. The method of claim 1, wherein the forward link frame comprises a plurality of symbols in a time domain, and

the primary synchronization signal and each of the secondary synchronization signals are mapped to two adjacent symbols.

4. The method of claim 1, wherein the forward link frame comprises a plurality of symbols in a time domain, and

the primary synchronization signal is repeatedly disposed on at least two symbols.

5. The method of claim 1, wherein the secondary synchronization signals provide timing information of a start of the forward link frame.

6. An apparatus for generating a forward link frame in a communication system in which a plurality of cells are grouped into a plurality of cell groups, and each cell group includes at least two cells, the apparatus comprising:

means for generating secondary synchronization signals for identifying a cell group;

means for generating a primary synchronization signal for identifying a cell in the cell group corresponding to the secondary synchronization signals; and

means for generating the forward link frame using the secondary synchronization signals and the primary synchronization signal,

wherein the forward link frame comprises a plurality of symbols in a time domain,

the secondary synchronization signals are disposed on at least two symbols, respectively, and

the secondary synchronization signals disposed on the different symbols are different sequences from each other.

7. The apparatus of claim 6, wherein each cell belongs to only one of the plurality of cell groups.

8. The apparatus of claim 6, wherein the forward link frame comprises a plurality of symbols in a time domain, and

the primary synchronization signal and each of the secondary synchronization signals are mapped to two adjacent symbols.

9. The apparatus of claim 6, wherein the forward link frame comprises a plurality of symbols in a time domain, and

the primary synchronization signal is repeatedly disposed on at least two symbols.

10. The apparatus of claim 6, wherein the secondary synchronization signals provide timing information of a start of the forward link frame.

11. A method of searching a cell in a mobile station of a communication system in which a plurality of cells are grouped into a plurality of cell groups, and each cell group includes at least two cells, the method comprising:

detecting secondary synchronization signals and a primary synchronization signal from a received signal; and

identifying a cell ID using information of the secondary and primary synchronization signals,

wherein the secondary synchronization signals include information of a cell group to which the mobile station belongs, and the primary synchronization signal includes information of a cell to which the mobile station belongs among cells within the cell group,

wherein a frame of the received signal comprises a plurality of symbols in a time domain,

the secondary synchronization signals are disposed on at least two symbols, respectively, and

the secondary synchronization signals disposed on the different symbols are different sequences from each other.

12. The method of claim 11, wherein each cell belongs to only one of the plurality of cell groups.

13. The method of claim 11, wherein a frame of the received signal comprises a plurality of symbols in a time domain, and

the primary synchronization signal and each of the secondary synchronization signals are mapped to two adjacent symbols.

14. The method of claim 11, wherein a frame of the received signal comprises a plurality of symbols in a time domain, and

the primary synchronization signal is repeatedly disposed on at least two symbols.

15. The method of claim 11, wherein the secondary synchronization signals provide timing information of a start of a forward link frame.

16. An apparatus for searching a cell in a mobile station of a communication system in which a plurality of cells are grouped into a plurality of cell groups, and each cell group includes at least two cells, the apparatus comprising:

means for detecting secondary synchronization signals and a primary synchronization signal from a received signal; and

means for identifying a cell ID using information of the secondary and primary synchronization signals,

wherein the secondary synchronization signals include information of a cell group to which the mobile station belongs, and the primary synchronization signal includes information of a cell to which the mobile station belongs among cells within the cell group,

wherein a frame of the received signal comprises a plurality of symbols in a time domain,

the secondary synchronization signals are disposed on at least two symbols, respectively, and

the secondary synchronization signals disposed on the different symbols are different sequences from each other.

17. The apparatus of claim 16, wherein each cell belongs to only one of the plurality of cell groups.

18. The apparatus of claim 16, wherein a frame of the received signal comprises a plurality of symbols in a time domain, and

the primary synchronization signal and each of the secondary synchronization signals are mapped to two adjacent symbols.

19. The apparatus of claim 16, wherein a frame of the received signal comprises a plurality of symbols in a time domain, and

the primary synchronization signal is repeatedly disposed on at least two symbols.

20. The apparatus of claim 16, wherein the secondary synchronization signals provide timing information of a start of a forward link frame.

21. A non-transitory computer-readable medium having a program stored thereon for executing a method in a communication system in which a plurality of cells are grouped into a plurality of cell groups, and each cell group includes at least two cells, the method comprising:

generating secondary synchronization signals for identifying a cell group;

generating a primary synchronization signal for identifying a cell in the cell group corresponding to the secondary synchronization signals; and

generating a forward link frame using the secondary synchronization signals and the primary synchronization signal,

wherein the forward link frame comprises a plurality of symbols in a time domain,

the secondary synchronization signals are disposed on at least two symbols, respectively, and

the secondary synchronization signals disposed on the different symbols are different sequences from each other.

22. The non-transitory computer-readable medium of claim 21, wherein each cell belongs to only one of the plurality of cell groups.

23. The non-transitory computer-readable medium of claim 21, wherein the forward link frame comprises a plurality of symbols in a time domain, and

the primary synchronization signal and each of the secondary synchronization signals are mapped to two adjacent symbols.

24. The non-transitory computer-readable medium of claim 21, wherein the forward link frame comprises a plurality of symbols in a time domain, and

the primary synchronization signal is repeatedly disposed on at least two symbols.

25. The non-transitory computer-readable medium of claim 21, wherein the secondary synchronization signals provide timing information of a start of the forward link frame.