Maximum Combining In Broadcast OFDM Systems Based On Multiple Receive Antennas

• US 20150003380A1
• Filed: 09/12/2014
• Published: 01/01/2015
• Est. Priority Date: 09/27/2005
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Ling, Fuyun, Li, Linbo, Mantravadi, Ashok
• Granted Patent: US 9,923,611 B2
• Time in Patent Office: Days
• US Class Current: 370/329
• CPC Class Codes: H04B 7/0404 the mobile station comprising multiple antennas, e.g. to provide uplink diversity
• CPC Class Codes: H04B 7/0805 with single receiver and antenna switching H04B7/0822 takes precedence
• CPC Class Codes: H04B 7/0808 comparing all antennas before reception
• CPC Class Codes: H04B 7/0811 during preamble or gap period
• CPC Class Codes: H04B 7/0814 based on current reception conditions, e.g. switching to different antenna when signal level is below threshold
• CPC Class Codes: H04B 7/0857 using maximum ratio combining techniques, e.g. signal-to- interference ratio [SIR], received signal strenght indication [RSS]
• CPC Class Codes: H04B 7/0874 using subgroups of receive antennas
• CPC Class Codes: H04L 1/0003 by switching between different modulation schemes
• CPC Class Codes: H04L 1/0057 Block codes H04L1/0061, H04L1/0064 take precedence
• CPC Class Codes: H04L 1/0066 Parallel concatenated codes
• CPC Class Codes: H04L 25/022 of frequency response
• CPC Class Codes: H04L 27/2647 Arrangements specific to the receiver only equalisation H04L27/01
• CPC Class Codes: H04W 72/542 using measured or perceived quality

Abstract

Systems and methods are provided for enhancing signal quality at receivers in a wireless network. In one embodiment, an antenna is selected from a subset of antennas based on a signal quality parameter such as received signal power or signal-to-noise ratio (SNR). In another embodiment, multiple antennas are applied to independent signal processing paths for the respective antennas where output from the paths is then combined to enhance overall signal quality at the receiver.

Claims

1. A method for receiving data in a wireless network, comprising:

receiving signals at a plurality of antennas;

selecting a subset of antennas from among the plurality of antennas, wherein the subset of antennas includes at least two antennas;

selecting a processing path from a set of processing paths based on a parameter representative of a Doppler spread associated with the signals received by the subset of antennas, wherein the selected processing path is used to process signals received by at least one antenna included in the subset of antennas to facilitate data reception, wherein the set of processing paths includes a switching processing path and a combining processing path, wherein the switching processing path performs data reception by selectively coupling a single antenna of the subset of antennas to a single receive chain included in a set of at least two receive chains, and wherein the combining processing path performs data reception by coupling each of the subset of antennas to a receive chain included in the set of at least two receive chains; and

performing data reception for the signals received by the subset of antennas using the selected processing path.

2. The method of claim 1, wherein the switching processing path is selected when the parameter satisfies a threshold representative of a small Doppler spread.

3. The method of claim 2, wherein the combining processing path is selected when the parameter does not satisfy the threshold.

4. The method of claim 1, wherein, when the selected processing path is the combining processing path, the method includes:

assigning the subset of antennas to the set of at least two receive chains, wherein each receive chain included in the set of at least two receive chains is assigned to a single antenna of the subset of antennas; and

processing the signals received by the subset of antennas using the set of at least two receive chains; and

combining outputs of the set of at least two receive chains to facilitate data reception.

5. The method of claim 4, wherein the outputs of the set of at least two receive chains are combined using maximum ratio combining.

6. The method of claim 1, wherein, when the selected processing path is the switching processing path, the method includes:

selectively coupling each antenna of the subset of antennas to a receive chain;

determining signal quality parameters for each antenna selectively coupled to the receive chain, wherein a signal quality parameter for a particular antenna is representative of a quality of the signal received by the particular antenna;

selecting the single antenna based on the signal quality parameters; and

processing signals received by the single antenna using the single receive chain.

7. The method of claim 1, wherein the subset of antennas includes more than two antennas, and wherein the combining processing path includes more than two receive chains.

8. A computer-readable storage medium storing instructions that, when executed by a processor, cause the processor to perform operations for receiving data in a wireless network, the operations comprising:

receiving signals at a plurality of antennas;

selecting a subset of antennas from among the plurality of antennas, wherein the subset of antennas includes at least two antennas;

selecting a processing path from a set of processing paths based on a parameter representative of a Doppler spread associated with the signals received by the subset of antennas, wherein the selected processing path is used to process signals received by at least one antenna included in the subset of antennas to facilitate data reception, wherein the set of processing paths includes a switching processing path and a combining processing path, wherein the switching processing path performs data reception by selectively coupling a single antenna of the subset of antennas to a single receive chain included in a set of at least two receive chains, and wherein the combining processing path performs data reception by coupling each of the subset of antennas to a receive chain included in the set of at least two receive chains; and

performing data reception for the signals received by the subset of antennas using the selected processing path.

9. The computer-readable storage medium of claim 8, wherein the switching processing path is selected when the parameter satisfies a threshold representative of a small Doppler spread, and wherein the combining processing path is selected when the parameter does not satisfy the threshold.

10. The computer-readable storage medium of claim 8, wherein, when the selected processing path is the combining processing path, the operations include:

assigning the subset of antennas to the set of at least two receive chains, wherein each receive chain included in the set of at least two receive chains is assigned to a single antenna of the subset of antennas; and

processing the signals received by the subset of antennas using the set of at least two receive chains; and

combining outputs of the set of at least two receive chains to facilitate data reception, wherein the outputs of the set of at least two receive chains are combined using maximum ratio combining.

11. The computer-readable storage medium of claim 8, wherein, when the selected processing path is the switching processing path, the operations include:

coupling each antenna of the subset of antennas to a receive chain;

determining signal quality parameters for each antenna of the subset of antennas, wherein a signal quality parameter for a particular antenna is representative of a quality of the signal received by the particular antenna; and

selecting the single antenna based on the signal quality parameters; and

processing signals received by the single antenna using the single receive chain.

12. A wireless communication device for receiving data in a wireless network, comprising:

means for receiving signals at a plurality of antennas;

means for selecting a subset of antennas from among the plurality of antennas, wherein the subset of antennas includes at least two antennas;

means for selecting a processing path from a set of processing paths based on a parameter representative of a Doppler spread associated with the signals received by the subset of antennas, wherein the selected processing path is used to process signals received by at least one antenna included in the subset of antennas to facilitate data reception, wherein the set of processing paths includes a switching processing path and a combining processing path, wherein the switching processing path performs data reception by selectively coupling a single antenna of the subset of antennas to a single receive chain included in a set of at least two receive chains, and wherein the combining processing path performs data reception by coupling each antenna of the subset of antennas to a receive chain included in the set of at least two receive chains; and

means for performing data reception for the signals received by the subset of antennas using the selected processing path.

13. The wireless communication device of claim 12, wherein the switching processing path is selected when the parameter satisfies a threshold representative of a small Doppler spread, and wherein the combining processing path is selected when the parameter does not satisfy the threshold.

14. The wireless communication device of claim 12, wherein the means for performing data reception includes:

means for assigning the subset of antennas to the set of at least two receive chains, wherein each receive chain included in the set of at least two receive chains is assigned to a single antenna of the subset of antennas when the selected processing path is the combining processing path, wherein each receive chain is assigned to a single antenna of the subset of antennas; and

means for the signals received by the subset of antennas using the set of at least two receive chains when the selected processing path is the combining processing path; and

means for combining outputs of the set of at least two receive chains to facilitate data reception when the selected processing path is the combining processing path, wherein the outputs of the set of at least two receive chains are combined using maximum ratio combining.

15. The wireless communication device of claim 12, wherein the means for performing data reception includes:

means for coupling each antenna of the subset of antennas to a receive chain when the selected processing path is the switching processing path;

means for determining signal quality parameters for each antenna of the subset of antennas when the selected processing path is the switching processing path, wherein a signal quality parameter for a particular antenna is representative of a quality of the signal received by the particular antenna; and

means for selecting the single antenna of the subset antennas based on the signal quality parameters when the selected processing path is the switching processing path; and

means for processing signals received by the single antenna using the single receive chain when the selected processing path is the switching processing path.

16. A wireless communication device for receiving data in a wireless network, comprising:

a plurality of antennas for receiving signals;

at least two receive chains configured to facilitate data reception for the signals received by one or more of the plurality of antennas using a selected processing path; and

at least one processor configured to;

select a subset of antennas from among the plurality of antennas, wherein the subset of antennas includes at least two antennas; and

select the processing path for data reception from a set of processing paths based on a parameter representative of a Doppler spread associated with the signals received by the subset of antennas, wherein the selected processing path is used to process signals received by at least one antenna of the subset of antennas to facilitate data reception, wherein the set of processing paths includes a switching processing path and a combining processing path, wherein the switching processing path performs data reception by selectively coupling a single antenna of the subset of antennas to a single receive chain of the at least two receive chains, and wherein the combining processing path performs data reception by coupling each antenna included in the subset of antennas to a receive chain of the at least two receive chains.

17. The wireless communication device of claim 16, wherein the processor is configured to select the processing path based at least on detected movement of the at least two antennas.

18. The wireless communication device of claim 16, wherein, when the selected processing path is the combining processing path, the at least one processor is configured to:

assign the subset of antennas to the set of at least two receive chains, wherein each receive chain included in the set of at least two receive chains is assigned to a single antenna of the subset of antennas; and

process the signals received by the subset of antennas using the set of at least two receive chains; and

combine outputs of the set of at least two receive chains to facilitate data reception.

19. The wireless communication device of claim 16, further comprising:

a switch configured to selectively couple each antenna of the subset of antennas to a receive chain,

wherein, when the selected processing path is the switching processing path, the processor is configured to;

generate a signal configured to cause the switch to selectively couple each of the subset of antennas to the receive chain;

determine signal quality parameters for each antenna selectively coupled to the receive chain, wherein a signal quality parameter for a particular antenna is representative of a quality of the signal received by the particular antenna; and

select the single antenna of the at least two antennas based on the signal quality parameters, wherein the data reception is performed using signals received by the single antenna using the single receive chain.

20. The wireless communication device of claim 19, wherein the processor is configured to independently select a single antenna of the at least two antennas at each subcarrier based on the signal quality parameter for each antenna, wherein the single antenna at each subcarrier is coupled to one of the at least two receive chains to facilitate the data reception.