METHODS AND APPARATUS FOR ENHANCED COEXISTENCE ALGORITHMS IN WIRELESS SYSTEMS

• US 20110081858A1
• Filed: 10/05/2009
• Published: 04/07/2011
• Est. Priority Date: 10/05/2009
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: Apple Inc.
• Inventors: Giles, Michael Jason, Le, Huy, Thomason, Gary, Tolentino, Jaime, Hardell, David A., Chen, Camille
• Granted Patent: US 8,340,578 B2
• Time in Patent Office: Days
• US Class Current: 455/41.2
• CPC Class Codes: H04B 15/00 Suppression or limitation of noise or interference by means associated with receiver H04B1/10
• CPC Class Codes: H04B 17/318 Received signal strength
• CPC Class Codes: H04B 17/345 Interference values signal-to-interference ratio [SIR] or carrier-to-interference ratio [CIR] H04B17/336
• CPC Class Codes: H04L 1/0001 Systems modifying transmission characteristics according to link quality, e.g. power backoff adaptive data allocation for multicarrier modulation H04L5/0044; controlling transmission power for radio systems H04W52/04
• CPC Class Codes: H04L 1/20 using signal quality detector
• CPC Class Codes: H04L 5/0007 the frequencies being orthogonal, e.g. OFDM(A), DMT
• CPC Class Codes: H04L 5/0012 Hopping in multicarrier systems for frequency hopping in spread spectrum systems H04B1/713
• CPC Class Codes: H04L 5/0066 Requirements on out-of-channel emissions
• CPC Class Codes: H04W 24/00 Supervisory, monitoring or testing arrangements
• CPC Class Codes: H04W 24/02 Arrangements for optimising operational condition
• CPC Class Codes: H04W 28/0236 radio quality, e.g. interference, losses or delay
• CPC Class Codes: H04W 28/04 Error control
• CPC Class Codes: H04W 4/80 Services using short range communication, e.g. near-field communication [NFC], radio-frequency identification [RFID] or low energy communication
• CPC Class Codes: H04W 52/245 taking into account received signal strength
• CPC Class Codes: H04W 72/02 Selection of wireless resources by user or terminal
• CPC Class Codes: H04W 72/1215 for collaboration of different radio technologies
• CPC Class Codes: H04W 72/542 using measured or perceived quality
• CPC Class Codes: H04W 84/12 WLAN [Wireless Local Area Networks]
• CPC Class Codes: H04W 84/18 Self-organising networks, e.g. ad-hoc networks or sensor networks
• CPC Class Codes: H04W 88/06 adapted for operation in multiple networks or having at least two operational modes, e.g. multi-mode terminals

Abstract

Methods and apparatus for mitigating the effects of interference between multiple air interfaces located on an electronic device. In one embodiment, the air interfaces include a WLAN interface and PAN (e.g., Bluetooth) interface, and information such as Receiver Signal Strength Index (RSSI) as well as system noise level information are used in order to intelligently execute interference mitigation methodologies, including the selective application of modified frequency selection, variation of transmitter power, and/or change of operating mode (e.g., from multiple-in multiple-out (MIMO) to single-in, single-out (SISO)) so as to reduce isolation requirements between the interfaces. These methods and apparatus are particularly well suited to use cases where the WLAN interface is operating with high data transmission rates. Business methods associated with the foregoing technology are also described.

Claims

1. A method for reducing interference in a wireless coexistence system, the wireless coexistence system including at least two differing wireless network interfaces that operate in at least a partially overlapping frequency band, the method comprising:

determining a receiver signal strength index (RSSI) at the wireless coexistence system;

determining a noise floor associated with the wireless coexistences system; and

implementing a coexistence algorithm to reduce interference in the wireless coexistence system based at least in part on the determined RSSI and determined noise floor.

2. The method of claim 1, wherein the coexistence algorithm adjusts the frequency utilization of at least one of the at least two differing wireless network interfaces.

3. The method of claim 2, wherein the coexistence algorithm adjusts the transmitter power of a transmitting one of the at least two wireless network interfaces.

4. The method of claim 2, wherein the coexistence algorithm imposes a data rate mask or limitation on a transmitting one of the at least two wireless network interfaces.

5. The method of claim 1, wherein the at least two wireless interfaces comprise a WLAN interface and a Bluetooth interface, and the act of implementing a coexistence algorithm comprises adjusting a channel map associated with an adaptive frequency hopping function of the Bluetooth interface.

6. The method of claim 5, wherein the adjusting a channel map comprises adjusting the selected frequencies of the map to maintain an increased frequency difference from a frequency associated with the WLAN interface relative to that of the adaptive frequency hopping function without such adjustment.

7. A wireless device, comprising:

a processing apparatus;

at least two differing wireless network interfaces that operate in at least a partially overlapping frequency band, at least one of the at least two differing wireless network interfaces operating according to a multiple-in multiple-out (MIMO) protocol; and

a computer readable apparatus having a storage medium with at least one computer program stored thereon, the at least one computer program comprising a plurality of computer executable instructions that when executed by the processing apparatus;

determine whether the wireless device is in an environment in which a first threshold for a system noise floor is exceeded;

if so, adjust a transmit power for at least one of the at least two differing wireless network interfaces;

determine whether the wireless device is in an environment in which a second threshold for the system noise floor is exceeded; and

if so, turn off at least one channel associated with the at least one wireless network interface operating according to the MIMO protocol.

8. The device of claim 7, wherein the at least two differing wireless interfaces comprise a WLAN interface and a Bluetooth interface, and the at least one computer program is further configured to:

measure a received signal strength using at least one of the interfaces;

evaluate the measured signal strength using one or more criteria; and

based at least in part on the evaluation, implement a modified adaptive frequency management protocol.

9. The device of claim 8, wherein the at least one computer program further comprises a plurality of computer executable instructions that when executed by the processing apparatus:

utilize an adjusted channel map associated with an adaptive frequency hopping function of the Bluetooth interface.

10. The device of claim 9, wherein the adjusted channel map comprises an adjusted portion of selected frequencies of the map to maintain an increased frequency difference from a center frequency associated with the WLAN interface relative to that of the adaptive frequency hopping function without such adjustment.

11. The device of claim 7, wherein the at least one computer program further comprises a plurality of computer executable instructions that when executed by the processing apparatus:

adjust the frequency utilization of at least one of the at least two differing wireless network interfaces.

12. A method for reducing interference in a wireless coexistence system, the wireless coexistence system including two wireless interfaces that operate in at least a partially overlapping frequency band, the method comprising:

determining a receiver signal strength index at one of the interfaces and based on the determined receiver signal strength index, selecting one of at least two different frequency use maps for a first of the two interfaces; and

determining a noise value associated with the wireless coexistence system and based on the determined noise value, selecting one of a plurality of operating modes of operation of a second of the two interfaces, the selected mode adjusting the transmit power of the second interface.

13. The method of claim 12, wherein the selected mode comprises a single-in single-out (SISO) mode of operation, while the other ones of the plurality of operating modes comprise multiple-in multiple-out (MIMO) modes of operation.

14. The method of claim 12, wherein at least one of the at least two different frequency use maps maintains an increased frequency difference from a center frequency associated with a first wireless interface relative to that of another one of the at least two different frequency use maps.

15. The method of claim 14, wherein the increased frequency difference from the center frequency is greater than 22 MHz for at least a portion of the at least one of the at least two different frequency use maps.

16. A method of operating a device having first and second air interfaces so as to mitigate interference therebetween without imposing time-sharing restrictions on either of the interfaces, the method comprising:

determining a received signal strength using at least one of the interfaces;

determining a noise parameter using at least one of the interfaces;

based on the acts of determining, selectively implementing a frequency use mapping for the first interface that substantially avoids one or more emitted sidebands associated with transmission from the second interface.

17. The method of claim 16, wherein the first interface comprises a PAN interface, the second interface comprises a WLAN interface, and the frequency use mapping comprises a mapping which allows only certain prescribed channels.

18. The method of claim 17, wherein the method further comprises:

after said selectively implementing, determining again the noise parameter;

evaluating the again determined noise parameter; and

based at least in part on the evaluation, implementing at least one of (i) transmitter power reduction on the WLAN interface; and

/or (ii) changing the mode of operation of the WLAN interface from multiple-in, multiple-out (MIMO) to single-in, single-out (SISO).

19. A method of operating a device having first and second wireless interfaces which overlap in frequency at least in part, the method comprising reducing the isolation requirements between the first and second interfaces through selective use of (i) frequency mapping for the first interface;

(ii) change in transmitter power for the second interface;

wherein the selective use is based in part on both signal strength and noise floor measurements within or proximate to the device.

20. A wireless device, comprising:

a processing apparatus;

at least two differing wireless network interfaces that operate in at least a partially overlapping frequency band; and

a computer readable apparatus having a storage medium with at least one computer program stored thereon, the at least one computer program comprising a plurality of computer executable instructions that when executed by the processing apparatus;

determine whether one of the at least two wireless network interfaces has a receiver signal strength index (RSSI) that exceeds a first criterion;

if so, read a first frequency utilization map for the one of the at least two wireless network interfaces, otherwise read a second frequency utilization map for the one of the at least two wireless network interfaces;

determine whether the wireless device is in an environment in which a first threshold for a system noise floor is exceeded;

if so, adjust a transmit power for at least one of the at least two differing wireless network interfaces;

if the transmit power is adjusted, determine whether the wireless device is in an environment in which a second threshold for the system noise floor is exceeded; and

if so, modify the operation of the at least one of the at least two differing wireless network interfaces.

21. The device of claim 20, wherein the modified operation comprises turning off at least one channel associated with the at least one wireless network interface operating according to a MIMO protocol.

22. The device of claim 20, wherein the modified operation comprises further adjusting the transmit power for the at least one of the at least two differing wireless network interfaces.