Position based signaling for short packets with minimal interference to the macro

• US 9,584,281 B2
• Filed: 01/04/2012
• Issued: 02/28/2017
• Est. Priority Date: 01/04/2012
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Tavildar, Saurabh, Sampath, Ashwin
• Primary Examiner(s): Cheng, Peter
• Application Number:
  US13/343,571
• Publication Number:
  US 20130170440A1
• Time in Patent Office: 1,882 Days
• Field of Search: 370328-330, 370436-437, 370/468
• US Class Current: 1/1
• CPC Class Codes: H04L 5/0007 the frequencies being orthogonal, e.g. OFDM(A), DMT
• CPC Class Codes: H04L 5/0053 Allocation of signaling, i.e. of overhead other than pilot signals
• CPC Class Codes: H04W 92/18 between terminal devices

Abstract

Methods and apparatus for communicating short messages from a first device, e.g., a femto cell device or peer to peer device, over communications resources which are being used by an OFDM macro network, e.g., cellular network, are described. The signal goes on top of, e.g., is transmitted on the same communications resource(s), on which a macro signal, e.g. a downlink signal from a cellular base station, is transmitted. Since the signals are transmitted on the same resources as the signals from the macro base station, they interfere with the macro signal. However, the signals transmitted by the femto cell devices and/or peer to peer devices are designed so that they cause little interference to the macro base station in terms of overall throughput and/or with the macro base station'"'"'s ability to communicate control and/or pilot information.

Claims

1. A method of operating a first communications device located within a cell of a base station, to communicate information to a second communications device, using communications resources which are also being used by said base station, the method comprising:

identifying resource blocks being used by the base station to communicate traffic data;

identifying in the first communications device, a first set of tone-symbols being used by said base station to communicate control signals, wherein the first set of tone-symbols is available in the resource blocks;

identifying in the first communications device, a second set of tone-symbols being used by the base station to communicate pilot signals, wherein the second set of tone-symbols is available in the resource blocks; and

reducing interference between the base station and a plurality of wireless terminals being serviced by the base station by communicating information from the first communications device to the second communications device by using position coding, wherein the second communications device is different than the base station, wherein using position coding comprises transmitting one or more non-null signals using one or more tone-symbols available in one or more positions in a resource block of the resource blocks other than tone-symbols belonging to either the first set or the second set and selecting a tone-symbol from among the one or more tone-symbols within the resource block to carry a non-null signal from among the one or more non-null signals based on the communicated traffic data and the position coding, wherein the one or more positions within the resource block of the one or more tone-symbols transmitted by using position coding are used to communicate the information, and wherein using position coding further comprises transmitting energy on between three-quarters of one percent to two percent of the tone-symbols in each resource block.

2. The method of claim 1, wherein the identifying the resource blocks includes:

storing base station transmission scheduling information identifying resource blocks used for transmitting control information and resource blocks used for transmitting traffic data;

synchronizing said first communications device to said base station; and

identifying resource blocks used by said base station for transmitting traffic data based on said stored base station transmission scheduling information and the first communications device timing synchronization with said base station.

3. The method of claim 2, wherein using position coding further comprises transmitting energy on no more than a single tone-symbol of each resource block.

4. The method of claim 3, wherein each resource block includes at least 50 tone-symbols.

5. The method of claim 1, wherein each resource block includes less than one hundred fifty tone-symbols.

6. The method of claim 1, wherein using position coding further comprises transmitting power on individual tone-symbols at a transmission power level which is at least as high as the highest transmission power level used by said first communications device to transmit traffic data.

7. The method of claim 1, wherein said first communications device is a femto cell device located in a macro cell corresponding to said base station.

8. The method of claim 1, further comprising:

selecting based on a position coding scheme, the one or more tone-symbols from among tone-symbols other than those belonging to either the first set or the second set.

9. The method of claim 1, wherein the one or more non-null signals comprise one or more discovery signals that are scheduled by the first communications device, independent of the base station.

10. A first communications device comprising:

means for identifying resource blocks being used by a base station to communicate traffic data;

means for identifying a first set of tone-symbols being used by the base station to communicate control signals, wherein the first set of tone-symbols is available in the resource blocks;

means for identifying a second set of tone-symbols being used by the base station to communicate pilot signals, wherein the second set of tone-symbols is available in the resource blocks; and

means for reducing interference between the base station and a plurality of wireless terminals being serviced by the base station by communicating information to a second communications device using position coding, wherein the second communications device is different than the base station, wherein using position coding comprises transmitting one or more non-null signals using one or more tone-symbols available in one or more positions in a resource block of the resource blocks other than tone-symbols belonging to either the first set or the second set and selecting a tone-symbol from among the one or more tone-symbols within the resource block to carry a non-null signal from among the one or more non-null signals based on the communicated traffic data and the position coding, wherein the one or more positions within the resource block of the one or more tone-symbols transmitted by using position coding are used to communicate the information, and wherein using position coding further comprises transmitting energy on between three-quarters of one percent to two percent of the tone-symbols in each resource block.

11. The first communications device of claim 10, wherein each non-null signal comprises a non-null femto signal, and wherein coded information is carried by a location of the non-null femto signal.

12. The first communications device of claim 10, wherein said means for identifying the resource blocks includes:

means for storing base station transmission scheduling information identifying resource blocks used for transmitting control information and resource blocks used for transmitting traffic data;

means for synchronizing said first communications device to said base station; and

means for identifying resource blocks used by said base station for transmitting traffic data based on said stored base station transmission scheduling information and the first communications device timing synchronization with said base station.

13. The first communications device of claim 10,

wherein each resource block includes less than one hundred fifty tone-symbols.

14. A computer program product for use in a first communications device to communicate with a second communications device, the computer program product comprising:

a non-transitory computer readable medium storing instructions executable by a processor to perform a method, the method comprising;

identifying resource blocks being used by a base station to communicate traffic data;

identifying a first set of tone-symbols being used by the base station to communicate control signals, wherein the first set of tone-symbols is available in the resource blocks;

identifying a second set of tone-symbols being used by the base station to communicate pilot signals, wherein the second set of tone-symbols is available in the resource blocks; and

reducing interference between the base station and a plurality of wireless terminals being serviced by the base station by communicating information with the second communications device using position coding, wherein using position coding comprises transmitting one or more non-null signals using one or more tone-symbols available in one or more positions in a resource block of the resource blocks other than tone-symbols belonging to either the first set or the second set and selecting a tone-symbol from among the one or more tone-symbols within the resource block to carry a non-null signal from among the one or more non-null signals based on the communicated traffic data and the position coding, wherein the one or more positions within the resource block of the one or more tone-symbols transmitted by using position coding are used to communicate the information, and wherein using position coding further comprises transmitting energy on between three-quarters of one percent to two percent of the tone-symbols in each resource block.

15. A first communications device comprising:

at least one processor configured to;

identify resource blocks being used by a base station to communicate traffic data;

identify a first set of tone-symbols being used by the base station to communicate control signals, wherein the first set of tone-symbols is available in the resource blocks;

identify a second set of tone-symbols being used by the base station to communicate pilot signals, wherein the second set of tone-symbols is available in the resource blocks; and

reduce interference between the base station and a plurality of wireless terminals being serviced by the base station by communicating information to a second communications device that is different than the base station using position coding, wherein using position coding comprises transmitting one or more non-null signals using one or more tone-symbols available in one or more positions in a resource block of the resource blocks other than tone-symbols belonging to either the first set or the second set and selecting a tone-symbol from among the one or more tone-symbols within the resource block to carry a non-null signal from among the one or more non-null signals based on the communicated traffic data and the position coding, wherein the one or more positions within the resource block of the one or more tone-symbols transmitted by using position coding are used to communicate the information, and wherein using position coding further comprises transmitting energy on between three-quarters of one percent to two percent of the tone-symbols in each resource block; and

memory coupled to said at least one processor.

16. The first communications device of claim 15, wherein each non-null signal comprises a non-null femto signal, and wherein coded information is carried by a location of the non-null femto signal.

17. The first communications device of claim 15, wherein said at least one processor is configured to:

store base station transmission scheduling information identifying resource blocks used for transmitting control information and resource blocks used for transmitting traffic data;

synchronize said first communications device to said base station; and

identify resource blocks used by said base station for transmitting traffic data based on said stored base station transmission scheduling information and the first communications device timing synchronization with said base station, as part of being configured to identify the first set of tone-symbols.

18. The first communications device of claim 15, wherein each resource block includes less than one hundred fifty tone-symbols.