Cell identifier encoding and decoding methods and apparatus

• US 20080080439A1
• Filed: 09/29/2006
• Published: 04/03/2008
• Est. Priority Date: 09/29/2006
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: Apple Inc.
• Inventors: Chandrasekhar, Vikram, McCoy, James Wesley, Aziz, Ahsan U.
• Granted Patent: US 8,228,887 B2
• Time in Patent Office: Days
• US Class Current: 370/338
• CPC Class Codes: H04B 1/7083 Cell search, e.g. using a three-step approach
• CPC Class Codes: H04J 13/0055 ZCZ [zero correlation zone]
• CPC Class Codes: H04J 13/0066 GCL [generalized chirp-like] sequences
• CPC Class Codes: H04J 13/16 Code allocation
• CPC Class Codes: H04J 2013/165 Joint allocation of code together with frequency or time
• CPC Class Codes: H04L 27/2613 Structure of the reference signals
• CPC Class Codes: H04L 27/2657 Carrier synchronisation
• CPC Class Codes: H04L 27/2662 Symbol synchronisation
• CPC Class Codes: H04L 5/0007 the frequencies being orthogonal, e.g. OFDM(A), DMT
• CPC Class Codes: H04L 5/0016 Time-frequency-code
• CPC Class Codes: H04L 5/0048 Allocation of pilot signals, i.e. of signals known to the receiver
• CPC Class Codes: H04W 56/00 Synchronisation arrangements
• CPC Class Codes: H04W 8/26 Network addressing or numbering for mobility support

Abstract

In an embodiment, a wireless communication system (100, FIG. 1) includes one or more nodes (102-108) and one or more user equipments (UE) (110). A node may apply (502, FIG. 5) a cell-specific spreading code to a cell identifier, which indicates an identity of a cell (113, FIG. 1) serviced by the node. The node may insert (504, FIG. 5), into a frame (200, FIG. 2), at least one synchronization channel symbol, which corresponds to the spread cell identifier, and the node may transmit (506, FIG. 5) the frame over an air interface. A UE may receive (702, FIG. 7) a frame from the air interface. The UE may despread (708) the spread cell identifier, and acquire (712) a cell identifier corresponding to a particular cell.

Claims

9. A method for communication between a node and a user equipment within a multi-carrier network, wherein the node is configured to transmit at least one frame over an air interface, the method comprising:

receiving at least one secondary synchronization channel symbol, which corresponds to a cell identifier to which a spreading code has been applied;

despreading the at least one secondary synchronization channel symbol using one or more cell-specific spreading codes to produce a despreading operation result; and

acquiring a cell identifier based on the despreading operation result, wherein the cell identifier indicates an identity of a cell serviced by a node that transmitted the at least one secondary synchronization channel symbol.

10. The method of claim 9, wherein despreading the at least one secondary synchronization channel symbol comprises:

despreading the at least one secondary synchronization channel symbol multiple times by applying, to the at least one secondary synchronization channel symbol, multiple cell-specific spreading codes assigned to multiple system nodes, to produce a despreading operation result that includes signal-to-interference plus noise ratio values associated with each of the multiple system nodes.

11. The method of claim 10, wherein applying the multiple cell-specific spreading codes comprises:

applying multiple substantially orthogonal spreading codes to the at least one secondary synchronization channel symbol.

12. The method of claim 10, wherein applying the multiple cell-specific spreading codes comprises:

applying multiple cell-specific spreading codes, each of which includes seven elements.

13. The method of claim 9, further comprising:

processing at least one primary synchronization channel symbol to perform coarse timing adjustment and carrier frequency offset correction prior to despreading the at least one secondary synchronization channel symbol.

14. The method of claim 9, further comprising:

registering with the node associated with the cell identifier.

15. The method of claim 9, further comprising:

handing off to the node associated with the cell identifier.

16. An apparatus comprising:

one or more integrated circuits to apply a spreading code to a cell identifier to produce a spread cell identifier, wherein the cell identifier indicates an identity of a cell serviced by a node of a multi-carrier network, and to insert at least one synchronization channel symbol into a frame, wherein the at least one synchronization channel symbol corresponds to the spread cell identifier.

1. A method for communication between a node and a user equipment within a multi-carrier network, wherein the node is configured to transmit at least one frame over an air interface, the method comprising:

applying, by the node, a spreading code to a cell identifier to produce a spread cell identifier, wherein the cell identifier indicates an identity of a cell that is serviced by the node; and

inserting at least one synchronization channel symbol into the frame, wherein the at least one synchronization channel symbol corresponds to the spread cell identifier.

2. The method of claim 1, wherein applying the spreading code comprises:

applying the spreading code to the cell identifier, wherein the cell identifier is represented by a generalized chirp like index and a tone index.

3. The method of claim 1, wherein applying the spreading code comprises:

applying a substantially orthogonal spreading code to the cell identifier.

4. The method of claim 1, wherein applying the spreading code comprises:

applying a spreading code that includes seven elements.

5. The method of claim 1, wherein inserting the at least one synchronization channel symbol comprises:

inserting, into the frame, a first synchronization symbol pair that includes a first primary synchronization channel symbol and a first secondary synchronization channel symbol, wherein the first primary synchronization channel symbol can be used to decode the first secondary synchronization channel symbol, and wherein a first part of the cell identifier can be encoded into the first secondary synchronization channel symbol; and

inserting, into the frame, a second synchronization symbol pair that includes a second primary synchronization channel symbol and a second secondary synchronization channel symbol, wherein the second primary synchronization channel symbol can be used to decode the second secondary synchronization channel symbol, and wherein a second part of the cell identifier can be encoded into the second secondary synchronization channel symbol.

6. The method of claim 1, further comprising:

transmitting the frame over an air interface.

7. The method of claim 6, wherein transmitting the frame comprises:

transmitting the frame synchronously with at least one other node.

8. The method of claim 6, further comprising:

transmitting the frame asynchronously from at least one other node.

18. The apparatus of claim 16, wherein the apparatus forms a portion of the node, and the apparatus further comprises:

one or more air interface subsystems, operably coupled to the one or more integrated circuits, to transmit the frame synchronously over an air interface.

18-1. The apparatus of claim 16, wherein the apparatus forms a portion of the node, and the apparatus further comprises:

one or more air interface subsystems, operably coupled to the one or more integrated circuits, to transmit the frame asynchronously over an air interface.

19. An apparatus comprising:

one or more integrated circuits to receive at least one secondary synchronization channel symbol, which corresponds to a cell identifier to which a spreading code has been applied, and to despread the at least one secondary synchronization channel symbol using at least one cell-specific spreading code to produce a despreading operation result, and to acquire a cell identifier based on the despreading operation result, wherein the cell identifier indicates an identity of a cell serviced by a node that transmitted the at least one secondary synchronization channel symbol.

20. The apparatus of claim 19, wherein the apparatus forms a portion of a user equipment, and the apparatus further comprises:

one or more air interface subsystems, operably coupled to the one or more integrated circuits, to receive the at least one synchronization channel symbol over an air interface.