Methods and apparatus for efficient digital broadcast signaling in a wireless communications system

• US 7,990,840 B2
• Filed: 03/07/2006
• Issued: 08/02/2011
• Est. Priority Date: 03/08/2005
• Status: Expired due to Fees

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Das, Arnab, Laroia, Rajiv, Li, Junyi
• Primary Examiner(s): Jagannathan; Melanie
• Application Number:
  US11/369,899
• Publication Number:
  US 20060223520A1
• Time in Patent Office: 1,974 Days
• Field of Search: 370/319, 370/328, 370/326, 370/331, 370/343, 370/345
• US Class Current: 370/208
• CPC Class Codes: H04B 7/022 Site diversity; Macro-diversity using two or more spaced independent antennas H04B7/04
• CPC Class Codes: H04B 7/0491 using two or more sectors, i.e. sector diversity
• CPC Class Codes: H04B 7/0671 using different delays between antennas
• CPC Class Codes: H04H 20/22 Arrangements for broadcast of identical information via plural broadcast systems
• CPC Class Codes: H04H 20/26 Arrangements for switching distribution systems
• CPC Class Codes: H04H 20/72 of terrestrial networks
• CPC Class Codes: H04L 27/2604 Multiresolution systems by means of multiresolution subcarriers H04L27/183, H04L27/3488
• CPC Class Codes: H04W 52/143 Downlink power control
• CPC Class Codes: H04W 52/322 Power control of broadcast channels
• CPC Class Codes: H04W 52/42 in systems with time, space, frequency or polarisation diversity
• CPC Class Codes: H04W 52/54 Signalisation aspects of the TPC commands, e.g. frame structure

Abstract

First and second transmitters transmit signals communicating the same information, e.g., program segment, but at different times. Different carriers may, but need not be, used by the different transmitters. If a wireless terminal can not recover broadcast segment information from one carrier, the wireless terminal can switch to another transmitter and recover the information, e.g., on another carrier, since the broadcasts are intentionally offset in time. In some embodiments, the timing is offset such that a single channel receiver is able to recover signals corresponding to the same program segment from two sources, and perform a decoding and information recovery using input from both sources, where recovery using input from a single source is not possible. Symbol level timing synchronization of base stations is not required thereby allowing for simpler implementations and/or lower overhead, as compared to systems which require base stations to be synchronized to the symbol timing level.

Claims

1. A method operating a wireless terminal, comprising:

receiving a first broadcast signal at a receiver, said first broadcast signal corresponding to a first program on a first carrier;

performing a first decoding operation on the first received broadcast signal;

determining whether said first decoding operation was unsuccessful; and

if it is determined that said decoding operation was unsuccessful, tuning said receiver to a second carrier to obtain a second broadcast signal corresponding to the first program, said second carrier having a frequency which is different from a frequency of said first carrier,

wherein the first and second carriers each broadcast the first program concurrently, and

wherein the respective received broadcasts of the first program in the first and second carriers are deliberately offset from each other in time.

2. The method of claim 1, further comprising:

operating the wireless terminal to receive the second broadcast signal corresponding to the first program on the second carrier.

3. The method of claim 2, further comprising:

performing a decoding operation on the received second broadcast signal.

4. The method of claim 3, further comprising:

determining whether said second decoding operation was unsuccessful; and

if it is determined that said decoding operation was unsuccessful, tuning said receiver to the first carrier.

5. The method of claim 4, further comprising:

switching between the first and second carriers on an ongoing basis if a received signal can not be decoded.

6. The method of claim 1, where the first carrier is associated with a first base station transmitter and the second carrier is associated with a second base station transmitter, said first and second base station transmitters being located in adjacent cells or sectors.

7. The method of claim 1, wherein said first and second broadcast signals include the same program content of the first program but are received at different times such that the second broadcast signal corresponds to a time-delayed version of the first broadcast signal.

8. The method of claim 7, further comprising:

combining the first and second broadcast signals to generate a presentable copy of said first program.

9. The method of claim 1, wherein the first and second broadcast signals contain the same content portion of the first program.

10. The method of claim 1, wherein broadcast signals on the second carrier are each deliberately time-delayed versions of corresponding broadcast signals on the first carrier.

11. A wireless terminal, comprising:

a receiver for receiving broadcast signals associated with a broadcast program and transmitted on first and second carriers, said first and second carriers having different frequencies, wherein the first and second carriers broadcast the broadcast program concurrently, and wherein the respective transmissions of corresponding broadcast signals associated with the broadcast program in the first and second carriers are deliberately offset from each other in time;

a decoder coupled to said receiver for performing decoding operations on the received broadcast signals;

a decoding operation evaluation module for determining whether decoding of a broadcast signal was unsuccessful; and

a control module for controlling said receiver to switch receiving said broadcast signals between said first and second carriers in response to said decoding operation evaluation module determining that a decoding operation was unsuccessful.

12. The wireless terminal of claim 11, further comprising:

a program segment combining module for combining program segments generated by decoding signals received on different carriers to generate a presentable copy of said broadcast program.

13. The wireless terminal of claim 11, wherein the same program segments can be recovered from signals transmitted on both the first and second carriers but at different times, said control module including switching functionally which switches within a period of time which is less than a time offset between segment transmission having the same information content.

14. The wireless terminal of claim 12, further comprising:

a carrier strength monitoring module for checking the strength of signals indicative of the received strength of said first and second carrier signals; and

a carrier selection module for performing a carrier selection operation as a function of the relative received strengths of the first and second carriers as determined by the carrier strength monitoring module.

15. The wireless terminal of claim 12, wherein said receiver is a single carrier receiver capable of receiving a single carrier at a time.

16. The wireless terminal of claim 11, where the first carrier is associated with a first base station transmitter and the second carrier is associated with a second base station transmitter, said first and second base station transmitters being located in adjacent cells or sectors.

17. A wireless terminal, comprising:

receiver means for receiving broadcast signals associated with a broadcast program and transmitted on first and second carriers, said first and second carriers having different frequencies, wherein the first and second carriers broadcast the broadcast program concurrently, and wherein the respective transmissions of corresponding broadcast signals associated with the broadcast program in the first and second carriers are deliberately offset from each other in time;

decoder means coupled to said receiver for performing decoding operations on the received broadcast signals;

decoding operation evaluation means for determining whether decoding of a broadcast signal was unsuccessful; and

control means for controlling said receiver to switch between said first and second carriers in response to said decoding operation evaluation module determining that a decoding operation was unsuccessful.

18. The wireless terminal of claim 17, further comprising:

program segment combining means for combining program segments generated by decoding signals received on different carriers to generate a presentable copy of said broadcast program.

19. The wireless terminal of claim 17, wherein the same program segments can be recovered from signals transmitted on both the first and second carriers but at different times, said control means including means for switching between the first and second carriers within a period of time which is less than a time offset between segment transmission having the same information content.

20. The wireless terminal of claim 18, further comprising:

carrier strength monitoring means for checking the strength of signals indicative of the received strength of said first and second carrier signals; and

a carrier selection means for performing a carrier selection operation as a function of the relative received strengths of the first and second carriers as determined by the carrier strength monitoring module.

21. A non-transitory computer readable medium embodying instructions which, in response to being executed by a processor direct said processor to:

operate a wireless terminal to;

receive at a receiver a first broadcast signal corresponding to a first program on a first carrier;

perform a first decoding operation on the first received broadcast signal;

determine whether said first decoding operation was unsuccessful; and

if it is determined that said decoding operation was unsuccessful, tune said receiver to a second carrier to obtain a second broadcast signal corresponding to the first program, said second carrier having a frequency that is different from a frequency of said first carrier,

wherein the first and second carriers each broadcast the first program concurrently, and

wherein the respective received broadcasts of the first program in the first and second carriers are deliberately offset from each other in time.

22. The non-transitory computer readable medium of claim 21, wherein said instructions, in response to being executed by said processor, further direct said processor to:

operate the wireless terminal to receive the second broadcast signal corresponding to the first program on the second carrier.

23. The non-transitory computer readable medium of claim 22, wherein said instructions, in response to being executed by said processor, further direct said processor to:

operate the wireless terminal to perform a decoding operation on the received second broadcast signal.

24. The non-transitory computer readable medium of claim 23, wherein said instructions, in response to being executed by said processor, further direct said processor to:

operate the wireless terminal to;

determine whether said second decoding operation was unsuccessful; and

if it is determined that said decoding operation was unsuccessful, tune said receiver to the first carrier.

25. The non-transitory computer readable medium of claim 24, wherein said instructions, in response to being executed by said processor, further direct said processor to:

operate the wireless terminal to switch between the first and second carriers on an ongoing basis when a received signal cannot be decoded.