Collaborative mechanism of enhanced coexistence of collocated wireless networks

• US 20050239474A9
• Filed: 10/25/2001
• Published: 10/27/2005
• Est. Priority Date: 01/16/2001
• Status: Active Grant

• Current Assignee: Texas Instruments, Inc.
• Original Assignee: Texas Instruments, Inc.
• Inventors: Liang, Jie
• Granted Patent: US 7,099,671 B2
• Time in Patent Office: Days
• US Class Current: 455/454
• CPC Class Codes: H04W 16/14 Spectrum sharing arrangements between different networks
• CPC Class Codes: H04W 72/1215 for collaboration of different radio technologies

Abstract

A digital device 310 with a plurality of collocated wireless networks encounters inter-network interference if the collocated wireless networks operate in a common operating frequency. A coordinator unit 510, coupled to the plurality of wireless networks, provides a transmission reservation system wherein a wireless network with a need to transmit can request and receive a reservation for time to transmit. The coordinator unit 510 provides a way to schedule transmissions from the plurality of wireless networks and to reduce the probability of collisions.

Claims

1. A method for controlling access to a wireless communications medium shared a plurality of collocated wireless networks comprising:

receiving a reservation request at a coordinator unit;

deciding upon the reservation request; and

returning the results of the decision.

2. The method of claim 1, wherein the deciding step further comprises:

determining if a desired time specified in the reservation request is available;

granting the reservation request if the desired time is available; and

rejecting the reservation request if the desired time is not available.

3. The method of claim 2, wherein the determining step further comprises:

generating a start time and a stop time for the reservation request based on information provided in the reservation request; and

comparing the start time and the stop time for the reservation request against a list of granted start and stop times.

4. The method of claim 1, wherein the receiving step comprises receiving a single reservation request from one collocated wireless network.

5. The method of claim 1, wherein the receiving step comprises receiving a plurality of reservation requests for an overlapping transmission time from the plurality of collocated wireless networks.

6. The method of claim 5, wherein the deciding step further comprises:

selecting a random number, D;

comparing the random number against a threshold, DP; and

granting a reservation request from the plurality of reservation requests based on the comparison.

7. The method of claim 6, further comprises the step of rejecting all remaining reservation requests from the plurality of reservation requests.

8. The method of claim 7, wherein the returning step comprises returning a granted reservation request to a collocated wireless network whose reservation request was granted and returning rejected reservation requests to collocated wireless networks whose reservation requests were rejected.

9. The method of claim 6, wherein there are two collocated wireless networks, and wherein the threshold, DP, is a number between 0 and 1.

10. The method of claim 6, wherein there are three collocated wireless networks, and wherein the threshold, DP, is a set of two numbers between 0 and 1.

11. The method of claim 1, wherein the reservation request comprises a transmit start time and a transmit duration.

12. The method of claim 1, wherein the reservation request comprises a transmit start time and a transmit stop time.

13. A method for sharing a wireless communications medium among a plurality of collocated wireless networks comprising:

(a) determining a need to transmit;

(b) sending a reservation request to a coordinator unit;

(c) transmit if the reservation request was granted; and

(d) deferring transmission if the reservation request was rejected.

14. The method of claim 13, wherein the determining step comprises decoding a message addressed to self that requires a response.

15. The method of claim 13, wherein the determining step comprises receiving a message addressed to self that grants permission to transmit.

16. The method of claim 13, wherein the determining step comprises the assertion of a transmit indicator for transmission of a periodic transmission.

17. The method of claim 13, wherein the determining step comprises servicing a request to grant permission to transmit.

18. The method of claim 13, wherein the determining step further comprises:

determining that the wireless communications medium is idle;

waiting a specified time interval;

generating a random backoff time;

loading the random backoff time into a backoff timer;

decrementing the backoff timer each time an idle network slot expires; and

determining when the backoff timer reaches zero.

19. The method of claim 13, wherein the deferring step further comprises:

waiting until a next available transmission time; and

repeating steps (b)-(d).

20. The method of claim 13, wherein the deferring step further comprises:

sending a reservation request to the coordinator unit, requesting a next available time; and

repeating steps (c)-(d).

21. The method of claim 13, wherein the deferring step comprises repeating steps (a)-(d).

22. A coordinator unit comprising:

a reservation request flag line, the reservation request flag line to denote a status of a pending reservation request;

an arbiter unit coupled to the reservation request flag line, the arbiter unit containing circuitry to receive reservation requests and to grant reservation requests based on the state of the reservation request flag line; and

a scheduler unit coupled to the arbiter unit and the reservation request flag line, the scheduler unit containing circuitry to maintain a list of granted reservation requests and to assert the status of a pending reservation request on the reservation request flag line.

23. The coordinator unit of claim 22, wherein there is a plurality of wireless networks interfaces collocated in a digital device, and wherein the coordinator unit is coupled to each wireless network interface.

24. The coordinator unit of claim 23, wherein the coupling is a wired connection between the coordinator unit and each wireless network interface.

25. The coordinator unit of claim 24, wherein each wired connection is an electrically separate connection.

26. The coordinator unit of claim 23, wherein the coupling is a wireless connection between the coordinator unit and each wireless network interface.

27. The coordinator unit of claim 26, wherein each wireless connection operates at a different operating frequency.

28. The coordinator unit of claim 26, wherein each wireless network operates on a common operating frequency, and wherein each wireless connection operates at a different operating frequency the common operating frequency of the wireless networks.

29. The coordinator unit of claim 22, wherein the coordinator unit further comprises a random number generator unit coupled to the arbiter unit, the random number generator unit containing circuitry to generate a random number in a range of 0 to 1.

30. The coordinator unit of claim 29, wherein the coordinator unit further comprises a threshold comparator unit coupled to the arbiter unit, the threshold comparator unit containing circuitry to compare the random number generated by the random number generator unit against a prespecified threshold.

31. The coordinator unit of claim 30, wherein the prespecified threshold is a number in a range of 0 to 1.

32. A digital device containing a plurality of collocated wireless networks comprising:

a plurality of wireless network interface, one wireless network interface for each of the plurality of collocated wireless networks, each wireless network interface provides an connection between the digital device and the wireless network interface'"'"'s respective wireless network;

a coordinator unit coupled to each wireless network interface, the coordinator unit further comprises;

a reservation request flag line, the reservation request flag line to denote a status of a pending reservation request;

an arbiter unit coupled to the reservation request flag line, the arbiter unit containing circuitry to receive reservation requests and to grant reservation requests based on the state of the reservation request flag line; and

a scheduler unit coupled to the arbiter unit and the reservation request flag line, the scheduler unit containing circuitry to maintain a list of granted reservation requests and to assert the status of a pending reservation request on the reservation request flag line.

33. The digital device of claim 32, wherein the digital device is a personal computer.

34. The digital device of claim 32, wherein the digital device is a personal digital assistant.

35. The digital device of claim 32, wherein the digital device is a cellular telephone.