Method and apparatus for minimizing a probability of self-interference among neighboring wireless networks

• US 6,278,723 B1
• Filed: 03/08/2000
• Issued: 08/21/2001
• Est. Priority Date: 03/08/2000
• Status: Expired due to Term

• Current Assignee: Google Technology Holdings LLC (Alphabet Inc.)
• Original Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Inventors: Dehner, Leo G., Meihofer, Eric F.
• Primary Examiner(s): Chin, Stephen
• Assistant Examiner(s): GHAYOUR, MOHAMMAD H
• Application Number:
  US09/521,153
• Time in Patent Office: 531 Days
• Field of Search: 375/133, 375/132, 375/131, 375/138, 375/220, 370/330, 370/338, 370/468, 455/63, 455/67.3
• US Class Current: 375/133
• CPC Class Codes: H04B 1/715 Interference-related aspects
• CPC Class Codes: H04B 1/7156 Arrangements for sequence synchronisation
• CPC Class Codes: H04B 2001/7154 with means for preventing interference
• CPC Class Codes: H04W 16/14 Spectrum sharing arrangements between different networks
• CPC Class Codes: H04W 56/00 Synchronisation arrangements

Abstract

A first master transceiver (102) of a first wireless network monitors (602) neighboring wireless networks to discover a strongest interfering master transceiver in one of the neighboring wireless networks. The first master transceiver then time-aligns (604) hop intervals of the first master transceiver with the hop intervals of the strongest interfering master transceiver to ensure that a transmission of the strongest interfering master transceiver during each hop interval used by the strongest interfering master transceiver cannot interfere with the transmission of the first master transceiver during more than one hop interval of the first master transceiver, thereby minimizing the probability of self-interference between the first wireless network and the one of the neighboring wireless networks.

Claims

1. A method for minimizing a probability of self-interference among neighboring wireless networks operating in accordance with differing frequency hopping plans that are not frequency-coordinated among the neighboring wireless networks, the method comprising in a first master transceiver of a first wireless network the steps of:

monitoring the neighboring wireless networks to discover a strongest interfering master transceiver in one of the neighboring wireless networks; and

time-aligning hop intervals of the first master transceiver with the hop intervals of the strongest interfering master transceiver to ensure that a transmission of the strongest interfering master transceiver during each hop interval used by the strongest interfering master transceiver cannot interfere with the transmission of the first master transceiver during more than one hop interval of the first master transceiver, thereby minimizing the probability of self-interference between the first wireless network and the one of the neighboring wireless networks.

2. The method of claim 1, wherein the monitoring step comprises the steps of:

measuring signal strengths of neighboring interfering master transceivers; and

selecting an interfering master transceiver having a highest signal strength as the strongest interfering master transceiver.

3. The method of claim 1, wherein the monitoring step comprises the step of:

measuring duty cycles of neighboring interfering master transceivers; and

selecting an interfering master transceiver as the strongest interfering master transceiver according to a duty cycle of the interfering master transceiver.

4. The method of claim 1, wherein the time-aligning step comprises the steps of:

time-aligning transmit hop intervals of the first master transceiver with the transmit hop intervals of the strongest interfering master transceiver; and

time-aligning receive hop intervals of the first master transceiver with the receive hop intervals of the strongest interfering master transceiver.

5. The method of claim 1, further comprising in the first master transceiver the steps of:

maintaining statistics on an outbound transmission quality and an inbound transmission quality while communicating with a slave transceiver;

detecting whether the outbound transmission quality is worse than the inbound transmission quality by more than a predetermined margin; and

commanding the slave transceiver to take control of the first wireless network as master, in response to detecting that the outbound transmission quality is worse than the inbound transmission quality by more than the predetermined margin.

6. The method of claim 1, further comprising in the first master transceiver the steps of:

continuing to monitor the neighboring wireless networks in an attempt to discover a different strongest interfering master transceiver; and

time-aligning the hop intervals of the first master transceiver with the hop intervals of the different strongest interfering master transceiver, in response to discovering the different strongest interfering master transceiver.

7. The method of claim 1, wherein the time-aligning step is performed sufficiently slowly to maintain uninterrupted synchronization with a slave transceiver in communication with the first master transceiver.

8. A first master transceiver of a first wireless network for minimizing a probability of self-interference among neighboring wireless networks operating in accordance with differing frequency hopping plans that are not frequency-coordinated among the neighboring wireless networks, the first master transceiver comprising:

a receiver for monitoring the neighboring wireless networks to discover a strongest interfering master transceiver in one of the neighboring wireless networks;

a processor coupled to the receiver and coupled to a transmitter for time-aligning hop intervals of the first master transceiver with the hop intervals of the strongest interfering master transceiver to ensure that a transmission of the strongest interfering master transceiver during each hop interval used by the strongest interfering master transceiver cannot interfere with the transmission of the first master transceiver during more than one hop interval of the first master transceiver, thereby minimizing the probability of self-interference between the first wireless network and the one of the neighboring wireless networks; and

the transmitter for sending information to a slave transceiver.

9. The first master transceiver of claim 8, wherein the processor is programmed to:

cooperate with the receiver to measure signal strengths of neighboring interfering master transceivers; and

select an interfering master transceiver having a highest signal strength as the strongest interfering master transceiver.

10. The first master transceiver of claim 8, wherein the processor is programmed to:

cooperate with the receiver to measure duty cycles of neighboring interfering master transceivers; and

select an interfering master transceiver as the strongest interfering master transceiver according to a duty cycle of the interfering master transceiver.

11. The first master transceiver of claim 8, wherein the processor is programmed to:

time-align transmit hop intervals of the first master transceiver with the transmit hop intervals of the strongest interfering master transceiver; and

time-align receive hop intervals of the first master transceiver with the receive hop intervals of the strongest interfering master transceiver.

12. The first master transceiver of claim 8, wherein the processor is programmed to:

maintain statistics on an outbound transmission quality and an inbound transmission quality while communicating with the slave transceiver;

detect whether the outbound transmission quality is worse than the inbound transmission quality by more than a predetermined margin; and

cooperate with the transmitter to command the slave transceiver to take control of the first wireless network as master, in response to detecting that the outbound transmission quality is worse than the inbound transmission quality by more than the predetermined margin.

13. The first master transceiver of claim 8, wherein the processor is programmed to:

continue to cooperate with the receiver to monitor the neighboring wireless networks in an attempt to discover a different strongest interfering master transceiver; and

time-align the hop intervals of the first master transceiver with the hop intervals of the different strongest interfering master transceiver, in response to discovering the different strongest interfering master transceiver.

14. The first master transceiver of claim 8, wherein the processor is programmed to time-align the hop intervals of the first master transceiver sufficiently slowly to maintain uninterrupted synchronization with the slave transceiver.

15. A first wireless network for minimizing a probability of self-interference with neighboring wireless networks operating in accordance with differing frequency hopping plans that are not frequency-coordinated among the neighboring wireless networks, the first wireless network comprising:

a first master transceiver arranged and programmed to;

monitor the neighboring wireless networks to discover a strongest interfering master transceiver in one of the neighboring wireless networks; and

time-align hop intervals of the first master transceiver with the hop intervals of the strongest interfering master transceiver to ensure that a transmission of the strongest interfering master transceiver during each hop interval used by the strongest interfering master transceiver cannot interfere with the transmission of the first master transceiver during more than one hop interval of the first master transceiver, thereby minimizing the probability of self-interference between the first wireless network and the one of the neighboring wireless networks; and

a slave transceiver communicating wirelessly with the first master transceiver.

16. The first wireless network of claim 15, wherein the first master transceiver is further arranged and programmed to:

measure signal strengths of neighboring interfering master transceivers; and

select an interfering master transceiver having a highest signal strength as the strongest interfering master transceiver.

17. The first wireless network of claim 15, wherein the first master transceiver is further arranged and programmed to:

measure duty cycles of neighboring interfering master transceivers; and

select an interfering master transceiver as the strongest interfering master transceiver according to a duty cycle of the interfering master transceiver.

18. The first wireless network of claim 15, wherein the first master transceiver is further arranged and programmed to:

time-align transmit hop intervals of the first master transceiver with the transmit hop intervals of the strongest interfering master transceiver; and

time-align receive hop intervals of the first master transceiver with the receive hop intervals of the strongest interfering master transceiver.

19. The first wireless network of claim 15, wherein the first master transceiver is further arranged and programmed to:

maintain statistics on an outbound transmission quality and an inbound transmission quality while communicating with the slave transceiver;

detect whether the outbound transmission quality is worse than the inbound transmission quality by more than a predetermined margin; and

command the slave transceiver to take control of the first wireless network as master, in response to detecting that the outbound transmission quality is worse than the inbound transmission quality by more than the predetermined margin.

20. The first wireless network of claim 15, wherein the first master transceiver is further arranged and programmed to:

continue to monitor the neighboring wireless networks in an attempt to discover a different strongest interfering master transceiver, and

time-align the hop intervals of the first master transceiver with the hop intervals of the different strongest interfering master transceiver, in response to discovering the different strongest interfering master transceiver.

21. The first wireless network of claim 15, wherein the first master transceiver is further arranged and programmed to time-align the hop intervals of the first master transceiver sufficiently slowly to maintain uninterrupted synchronization with the slave transceiver.