Cell Search in Wireless Communication System

• US 20140126568A1
• Filed: 01/10/2014
• Published: 05/08/2014
• Est. Priority Date: 07/11/2011
• Status: Active Grant

• Current Assignee: Huawei Technologies Co., Ltd. (Huawei Investment & Holding Co., Ltd.)
• Original Assignee: Huawei Technologies Co., Ltd. (Huawei Investment & Holding Co., Ltd.)
• Inventors: Berggren, Fredrik
• Granted Patent: US 9,282,506 B2
• Time in Patent Office: Days
• 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: H04L 25/0216 with estimation of channel length
• CPC Class Codes: H04L 27/2607 Cyclic extensions
• CPC Class Codes: H04L 27/2656 Frame synchronisation, e.g. packet synchronisation, time division duplex [TDD] switching point detection or subframe synchronisation
• CPC Class Codes: H04L 27/2662 Symbol synchronisation
• CPC Class Codes: H04L 5/001 the frequencies being arranged in component carriers
• CPC Class Codes: H04L 5/0053 Allocation of signaling, i.e. of overhead other than pilot signals
• CPC Class Codes: H04L 5/0094 Indication of how sub-channels of the path are allocated
• CPC Class Codes: H04W 48/16 Discovering, processing access restriction or access information
• CPC Class Codes: H04W 56/001 Synchronization between nodes
• CPC Class Codes: H04W 56/0015 one node acting as a reference for the others
• CPC Class Codes: H04W 56/0055 determining timing error of reception due to propagation delay

Abstract

A receiver performs synchronization to a secondary component carrier in a wireless communication system. The secondary component carrier is aggregated with a primary component carrier in the wireless communication system. Side information of the secondary component carrier is utilized to reduce occurrences of a number of synchronization hypotheses in a hypothesis test in the case that synchronization to the secondary component carrier is performed. Symbol timing synchronization of the secondary component carrier is determined in accordance with the reduced occurrences of the number of synchronization hypotheses.

Claims

1. A method of facilitating a receiver to perform synchronization to a secondary component carrier in a wireless communication system, the secondary component carrier being aggregated with a primary component carrier in the wireless communication system, the method comprising:

obtaining side information of the secondary component carrier;

utilizing the side information to reduce occurrences of a number of synchronization hypotheses in a hypothesis test in the case that synchronization to the secondary component carrier is performed; and

determining symbol timing synchronization of the secondary component carrier in accordance with the reduced occurrences of the number of the synchronization hypotheses.

2. The method of claim 1, wherein the side information is signaled to the receiver on the primary component carrier.

3. The method of claim 2, wherein the side information comprises any of:

a cell identity, a carrier frequency, a physical layer cell identity group number N_ID⁽¹⁾, and an identity number N_ID⁽²⁾ within a physical layer cell identity group.

4. The method of claim 3, wherein the cell identity is utilized as a verification of a cell identity detected in the synchronization of the receiver to the secondary component carrier.

5. The method of claim 1, wherein the side information is pre-determined and known to the receiver.

6. The method of claim 5, wherein the side information comprises any of:

a maximum timing error alignment, and a maximum channel delay spread.

7. The method of claim 1, wherein a number of the synchronization hypotheses is reduced by determining a reduced length of a receiver window, the receiver window being positioned in relation to detected synchronization of the primary component carrier.

8. The method of claim 7, wherein the reduced length is determined according to any of:

a maximum timing error alignment, and a maximum channel delay spread.

9. The method of claim 7, wherein the receiver window includes samples from the set S′

={n₁−

E, . . . , n₁+E}, where n₁ is a synchronization sample of the primary component carrier and 2E is the length of the receiver window.

10. The method of claim 1, wherein a number of the synchronization hypotheses is reduced by detecting a subset of primary synchronization signals.

11. The method of claim 1, wherein a number of the synchronization hypotheses is reduced by detecting a subset of secondary synchronization signals.

12. The method of claim 1, wherein a number of the synchronization hypotheses is reduced by applying frame synchronization detected for the primary component carrier on the secondary component carrier.

13. The method of claim 1, wherein a number of the synchronization hypotheses is reduced by detecting a secondary synchronization signal in time-domain.

14. The method of claim 13, wherein the secondary synchronization signal encodes frame timing of the secondary component carrier.

15. The method of claim 1, further comprising:

determining a cyclic prefix length of the secondary component carrier in accordance with reduced synchronization hypotheses; and

/or

determining frame timing synchronization of the secondary component carrier in accordance with reduced synchronization hypotheses.

16. The method of claim 1, wherein a number of the synchronization hypotheses is reduced by detecting all secondary synchronization signals of a radio frame in time-domain.

17. The method of claim 1, wherein the synchronization to the secondary component carrier is performed in an initial cell search facilitating the receiver to access a cell in the wireless communication system.

18. The method of claim 17, wherein the primary component carrier and the secondary component carrier are simultaneously used by the wireless communication system for communication of the receiver in the cell.

19. A receiver capable of performing synchronization to a secondary component carrier in a wireless communication system, the secondary component carrier being aggregated with a primary component carrier in the wireless communication system, the receiver comprising at least one processor configured to:

obtain side information of the secondary component carrier;

utilize the side information to reduce occurrences of a number of synchronization hypotheses in a hypothesis test in the case that synchronization to the secondary component carrier is performed; and

determine symbol timing synchronization of the secondary component carrier in accordance with the reduced occurrences of the number of synchronization hypotheses.

20. An apparatus for facilitating a receiver to perform synchronization to a secondary component carrier in a wireless communication system, the secondary component carrier being aggregated with a primary component carrier in the wireless communication system, the apparatus comprising at least one processor configured to:

obtain side information of the secondary component carrier;

utilize the side information to reduce occurrences of a number of synchronization hypotheses in a hypothesis test in the case that synchronization to the secondary component carrier is performed; and

determine symbol timing synchronization of the secondary component carrier in accordance with the reduced occurrences of the number of synchronization hypotheses.