METHOD AND APPARATUS FOR SYNCHRONIZATION IN AN OFDMA EVOLVED UTRA WIRELESS COMMUNICATION SYSTEM

• US 20160227498A1
• Filed: 04/08/2016
• Published: 08/04/2016
• Est. Priority Date: 04/18/2006
• Status: Active Grant

• Current Assignee: Interdigital Technology Corporation (InterDigital, Inc.)
• Original Assignee: Interdigital Technology Corporation (InterDigital, Inc.)
• Inventors: Zhang, Guodong, Pan, Kyle Jung-Lin, Tsai, Allan Yingming
• Granted Patent: US 10,123,293 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: H04J 11/00 Orthogonal multiplex systems, e.g. using WALSH codesH04J13/00 takes precedence
• 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: H04L 27/18 Phase-modulated carrier systems, i.e. using phase-shift keying H04L27/32 takes precedence
• CPC Class Codes: H04L 27/2613 Structure of the reference signals
• CPC Class Codes: H04L 27/2621 Reduction thereof using phase offsets between subcarriers
• CPC Class Codes: H04L 27/2655 Synchronisation arrangements
• 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 5/0023 Time-frequency-space
• CPC Class Codes: H04L 5/0048 Allocation of pilot signals, i.e. of signals known to the receiver
• CPC Class Codes: H04W 16/18 Network planning tools
• CPC Class Codes: H04W 56/00 Synchronisation arrangements
• CPC Class Codes: H04W 56/002 Mutual synchronization
• CPC Class Codes: H04W 72/0446 Resources in time domain, e.g. slots or frames
• CPC Class Codes: H04W 92/10 between terminal device and access point, i.e. wireless air interface

Abstract

A method and apparatus for synchronization in an orthogonal frequency division multiple access (OFDMA) evolved universal terrestrial radio access (E-UTRA) system including at least one base station and a plurality of wireless transmit/receive units (WTRUs). A secondary synchronization channel (S-SCH) symbol is generated to include cell-specific information. The S-SCH symbol is mapped to the center of the available bandwidth of the system. In one embodiment, the S-SCH symbol is transmitted on different subcarriers at different sectors in the system. In another embodiment, the S-SCH symbol is transmitted on the same subcarriers at different sectors in the system.

Claims

1. A user equipment for performing cell search in a long term evolution (LTE) network comprising:

a receiver and a processor configured to detect at least one primary synchronization signal and at least one secondary synchronization signal; and

the processor further configured in response to the detected at least one primary synchronization signal and the at least one secondary synchronization signal, to determine a radio frame timing and an identity of a cell that transmitted the primary synchronization signal and the secondary synchronization signal, wherein primary synchronization signals and secondary synchronization signals are received in a fixed number of subcarriers at a center of a system bandwidth, and wherein a transmission time interval (TTI) of one of the radio frames includes a primary synchronization signal and a secondary synchronization signal in respective orthogonal frequency division multiplex (OFDM) symbols of the TTI.

2. The user equipment of claim 1, wherein the primary synchronization signal and the secondary synchronization signal in the TTI are in adjacent OFDM symbols.

3. The user equipment of claim 1, wherein the secondary synchronization signals are binary phase shift keying modulated.

4. The user equipment of claim 1, wherein the secondary synchronization signals are derived from code sequences.

5. The user equipment of claim 1, wherein the secondary synchronization signals from different sectors are derived from different shifts of a sequence.

6. The user equipment of claim 1, wherein the primary synchronization signals are evenly spaced in the radio frames.

7. A method for use by a user equipment for performing cell search in a long term evolution (LTE) network, the method comprising:

detecting, by the user equipment, at least one primary synchronization signal and at least one secondary synchronization signal; and

in response to the detected at least one primary synchronization signal and the at least one secondary synchronization signal, determining a radio frame timing and an identity of a cell that transmitted the primary synchronization signal and the secondary synchronization signal, wherein primary synchronization signals and secondary synchronization signals are received in a fixed number of subcarriers at a center of a system bandwidth, and wherein a transmission time interval (TTI) of one of the radio frames includes a primary synchronization signal and a secondary synchronization signal in respective orthogonal frequency division multiplex (OFDM) symbols of the TTI.

8. The method of claim 7, wherein the primary synchronization signal and the secondary synchronization signal in the TTI are in adjacent OFDM symbols.

9. The method of claim 7, wherein the secondary synchronization signals are binary phase shift keying modulated.

10. The method of claim 7, wherein the secondary synchronization signals are derived from code sequences.

11. The method of claim 7, wherein the secondary synchronization signals from different sectors are derived from different shifts of a sequence.

12. The method of claim 7, wherein the primary synchronization signals are evenly spaced in the radio frames.

13. An eNodeB in a long term evolution (LTE) network comprising:

a transmitter operatively coupled to a processor and configured to transmit a primary synchronization signal and a secondary synchronization signal in a transmission time interval (TTI) of a radio frame, wherein an identity of a cell transmitting the primary synchronization signal and the secondary synchronization signal is determinable from the transmitted primary synchronization signal and secondary synchronization signal, wherein a frame timing of the radio frame is determinable from the transmitted primary synchronization signal and secondary synchronization signal, and wherein the primary synchronization signal and the secondary synchronization signal are transmitted in a same fixed number of subcarriers at a center of a system bandwidth of the cell and the primary synchronization signal and the secondary synchronization signal are transmitted in respective orthogonal frequency division multiplex (OFDM) symbols of the TTI.

14. The eNodeB of claim 13, wherein the primary synchronization signal and the secondary synchronization signal are in adjacent OFDM symbols.

15. The eNodeB of claim 13, wherein the secondary synchronization signal is binary phase shift keying modulated.

16. The eNodeB of claim 13, wherein the secondary synchronization signal is produced from a code sequence.

17. The eNodeB of claim 13, wherein secondary synchronization signals transmitted from different sectors are derived from different shifts of a sequence.