Configuration of overhead channels in a mixed bandwidth system

• US 20040233890A1
• Filed: 06/28/2004
• Published: 11/25/2004
• Est. Priority Date: 04/23/1999
• Status: Active Grant

• Current Assignee: Yu-Cheun Jou
• Original Assignee: Yu-Cheun Jou
• Inventors: Jou, Yu-Cheun
• Granted Patent: US 7,486,653 B2
• Time in Patent Office: Days
• US Class Current: 370/350
• CPC Class Codes: H04L 27/262 Reduction thereof by selection of pilot symbols
• CPC Class Codes: H04L 27/2657 Carrier synchronisation
• CPC Class Codes: H04L 5/0021 in which codes are applied as a frequency-domain sequences, e.g. MC-CDMA
• 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: H04L 5/0064 Rate requirement of the data, e.g. scalable bandwidth, data priority

Abstract

A method and apparatus for transmitting broadcast information in a multi-carrier communication system. The Sync Channel of the multi-carrier system is transmitted a 1.25 MHz channel bandwidth (i.e., over a single carrier), and to specify the preferred channels for the Sync Channel transmission instead of the preferred channels for the entire multi-carrier system. The Sync Channel Message will carry additional information indicating the center frequency of a multi-carrier system within a reserved set of frequency bands and indicating the frequency of a single carrier system in the reserved set of frequency bands. Considering the A block of the PCS band again, the preferred channels for Sync Channel transmission can be selected as channels 75, 150 and 225. This selection ensures that one of the preferred channels will always be used by any multi-carrier system regardless of the location of its center channel.

Claims

1. A method of acquiring sync channel by a mobile station in a mixed bandwidth communications system, said mobile station operable in at least one of a multi-carrier mode and a single carrier mode, comprising:

tuning to a first preferred channel of a selected set of preferred channels;

attempting to detect a pilot signal on the first preferred channel, wherein the pilot signal has a unique pilot signal offset;

receiving a sync channel message, if the pilot signal is detected on the first preferred channel; and

tuning to a second preferred channel of the selected set of preferred channels, if the pilot signal is not detected on the first preferred channel.

2. A method according to claim 1, wherein attempting to detect a pilot signal on the first preferred channel, wherein the pilot signal has a unique pilot signal offset, further comprises:

searching possible PN offset hypotheses; and

testing each PN offset hypothesis.

3. A method according to claim 2, wherein testing each PN offset hypothesis, further comprises:

computing the correlation between the received signal on the first preferred channel within the preferred frequency band and each PN hypothesis being tested to determine if the received signal is the pilot signal having a unique pilot signal offset.

4. A method according to claim 3, wherein the pilot signal is not detected on the first preferred channel if the correlation energy for all PN hypotheses is less than a threshold value.

5. A method according to claim 4, wherein the pilot signal is detected on the first preferred channel when a sufficient correlation energy is detected between the received signal at the preferred channel frequency and a PN offset hypothesis.

6. A method according to claim 1, wherein the sync channel message is transmitted in a single 1×

band, and a frame boundary of a sync channel frame and an interleaver boundary are aligned with a short PN sequence used to spread the pilot channel signal such that upon detection of the pilot channel signal the sync channel message can be de-interleaved and decoded.

7. A method according to claim 1, further comprising:

if the sync channel message is received,

determining the center frequency of a multi-carrier system from the sync channel message in the current set of bands if one exists; and

determining the location of a single carrier band in the current set of bands if one exists.

8. A method according to claim 7, wherein if the mobile station decides to operate in multi-carrier mode the mobile station uses the received Sync Channel message to determine the center frequency of a multi-carrier system in the current set of frequency bands if one exists, further comprising:

initiating RF hardware in the mobile station for multi-carrier reception;

receiving the broadcast channel (BCH) signal and from that channel learn among other information the number of common control channels used by the communication system; and

hashing the number of common control channels to determine the code channel that it should use to receive pages.

9. A method according to claim 7, wherein if the mobile station decides to operate in single carrier mode further comprises:

initiating RF hardware in the mobile station for single-carrier reception; and

receiving a general page message on a predetermined code channel that states the number of paging channels used by the system;

hashing the number of paging channels used to determine the code channel that it will use to receive directed pages from the serving base station.

10. A wireless device, operable in at least one of a multi-carrier mode and a single carrier mode, and configured to acquire a sync channel in a mixed bandwidth communications system, comprising:

means for tuning to a first preferred channel of a selected set of preferred channels;

means for attempting to detect a pilot signal on the first preferred channel, wherein the pilot signal has a unique pilot signal offset;

means for receiving a sync channel message, if the pilot signal is detected on the first preferred channel; and

means for tuning to a second preferred channel of the selected set of preferred channels, if the pilot signal is not detected on the first preferred channel.

11. A wireless device according to claim 10, wherein means for attempting to detect a pilot signal on the first preferred channel, comprises:

means for searching possible PN offset hypotheses; and

means for testing each PN offset hypothesis.

12. A wireless device according to claim 11, wherein means for testing each PN offset hypothesis, comprises:

means for computing the correlation between the received signal on the first preferred channel within the preferred frequency band and each PN hypothesis being tested to determine if the received signal is the pilot signal having a unique pilot signal offset.

13. A wireless device according to claim 12, wherein the pilot signal is not detected on the first preferred channel if the correlation energy for all PN hypotheses is less than a threshold value.

14. A wireless device according to claim 13, wherein the pilot signal is detected on the first preferred channel when a sufficient correlation energy is detected between the received signal at the preferred channel frequency and a PN offset hypothesis.

15. A wireless device according to claim 10, wherein the sync channel message is transmitted in a single 10×

band, and a frame boundary of a sync channel frame and a boundary are aligned with a short PN sequence used to spread the pilot channel signal such that upon detection of the pilot channel signal the sync channel message can be de-interleaved and decoded.

16. A wireless device according to claim 10, further comprising:

if the sync channel message is received,

means for determining the center frequency of a multi-carrier system from the sync channel message in the current set of bands if one exists; and

means for determining the location of a single carrier band in the current set of bands if one exists.

17. A wireless device according to claim 16, wherein if the wireless device decides to operate in multi-carrier mode the wireless device uses the received sync channel message to determine the center frequency of a multi-carrier system in the current set of frequency bands if one exists, further comprising:

means for initiating RF hardware in the wireless device for multi-carrier reception;

means for receiving the broadcast channel (BCH) signal and from that channel learn among other information the number of common control channels used by the communication system; and

means for hashing the number of common control channels to determine the code channel that it should use to receive pages.

18. A wireless device according to claim 16, wherein if the wireless device decides to operate in single carrier mode further comprises:

means for initiating RF hardware in the wireless device for single-carrier reception; and

means for receiving a general page message on a predetermined code channel that states the number of paging channels used by the system;

means for hashing the number of paging channels used to determine the code channel that it will use to receive directed pages from the serving base station.