Dynamic frequency hopping

• US 6,501,785 B1
• Filed: 12/28/1999
• Issued: 12/31/2002
• Est. Priority Date: 11/17/1999
• Status: Expired due to Term

• Current Assignee: AT&T Corporation (AT&T, Inc.)
• Original Assignee: AT&T Corporation (AT&T, Inc.)
• Inventors: Sollenberger, Nelson, Chang, Li Fung, Kostic, Zoran, Qiu, Xiaoxin, Chawla, Kapil K., Chuang, Justin C.
• Primary Examiner(s): Le, Amanda T.
• Application Number:
  US09/472,784
• Time in Patent Office: 1,099 Days
• Field of Search: 375/130, 375/132, 375/133, 375/135, 375/134, 375/136, 375/137, 370/252, 370/337, 370/442, 455/452
• US Class Current: 375/133
• CPC Class Codes: H04B 7/2621 using frequency division multiple access [FDMA] H04B7/2615 takes precedence
• CPC Class Codes: H04W 16/10 Dynamic resource partitioning

Abstract

This invention provides a dynamic frequency hopping system that utilizes information from multiple base stations. The system assigns frequency hopping patterns based on current interference and traffic environments to avoid interference thus gaining the benefits of interference averaging and interference avoidance. The system imposes less stringent measurement requirements on terminals (wireless mobile devices) because many measurement requirements are replaced by generating estimates based on measurement data received from other base stations within a base station neighborhood. The system may continuously verify that the frequency hopping patterns assigned to the links of the system optimizes system performance. The system compares system performance of possible frequency hopping patterns against currently assigned frequency hopping pattern to optimize system performance. When a request for a link is received, a similar process as above is performed where the request is granted/denied/delayed based on system optimization requirements. In this way, the frequency hopping patterns of the links of the system may be assigned so that an optimum system performance may be obtained.

Claims

1. A method for assigning frequency hopping patterns in a communication system 1, comprising:

identifying available frequencies for one or more links based on information received from one or more base stations in base station neighborhoods of base stations servicing the links; and

assigning a portion of the available frequencies to form frequency hopping patterns for the links based on system performance parameters.

2. The method of claim 1, wherein the identifying comprises determining available frequencies corresponding to a selected link of the links, the method further comprising:

including unassigned frequencies in the available frequencies; and

including frequencies assigned to first currently active links in the available frequencies if the selected link is not included in link neighborhoods of the first currently active links.

3. The method of claim 2, further comprising including frequencies assigned to each of second currently active links whose link neighborhoods include the selected link if a performance of each of the second currently active links for the assigned frequencies falls below a threshold.

4. The method of claim 2, wherein a base station neighborhood of the base station neighborhoods corresponds to a base station, the base station neighborhood including base stations that service links whose link neighborhoods include the selected link.

5. The method of claim 1, wherein the assigning frequency hopping patterns comprises:

generating a link quality for each frequency of a frequency hopping pattern of a link;

identifying a first number of replaceable frequencies of the frequency hopping pattern that have link qualities that are less than a link quality threshold;

marking the link if the first number exceeds a marking threshold; and

assigning the replacement frequencies to links that are marked.

6. The method of claim 5, wherein the assigning replacement frequencies comprises:

selecting randomly a second number of the available frequencies that correspond to the link, each of the second number of the available frequencies having a link quality that exceeds an assigning threshold, the second number being the same as the first number; and

assigning the second number of selected available frequencies to replace the first number of replaceable frequencies.

7. The method of claim 5, wherein the assigning replacement frequencies comprises:

selecting a second number of the available frequencies that correspond to the link, have largest link qualities and exceed the link quality threshold, the second number being the same as the first number; and

assigning the second number of the selected available frequencies to replace the replaceable frequencies.

8. The method of claim 5, wherein the link quality includes signal-interference-plus-noise-ratio (SINR), block error rate or bit error rate quality.

9. The method of claim 1, wherein the assigning frequency hopping patterns comprises:

selecting ones of the available frequencies that;

a) correspond to a selected link, and

b) either optimize an estimated performance of the link, or optimize estimated performances of one or more other links serviced by a base station servicing the link; and

assigning the selected ones of the available frequencies to a new frequency pattern for the link.

10. The method of claim 9, wherein the optimum estimated performance includes one or more of highest estimated throughput, an estimated throughput that exceeds a throughput threshold, a predetermined level of estimated quality of service, a maximum number of terminals serviced at a set level of estimated quality, or an estimated error rate less than a error rate threshold.

11. The method of claim 1, wherein the assigning frequency hopping patterns comprises:

receiving a token in a base station;

selecting ones of the available frequencies that correspond to the link and optimize an estimated communication system performance; and

assigning the selected ones of the available frequencies to a new frequency pattern for the link.

12. The method of claim 1, wherein the assigning frequency hopping patterns comprises:

receiving information from all base station of the communication system in a centralized unit;

selecting ones of the available frequencies that optimize an estimated communication system performance; and

assigning the selected ones of the available frequencies to new frequency patterns to the links.

13. The method of claim 1, wherein the communication system uses time division multiplexing (TDM), the method further comprising:

identifying available slots corresponding to the identified available frequencies;

assigning a combination of the available slots and the available frequencies based on system performance parameters.

14. A dynamic frequency hopping communication system, comprising:

a database;

a dynamic frequency hopping management device coupled to the database, the dynamic frequency hopping management device identifies available frequencies for one or more links based on information received from one or more base stations in base station neighborhoods of base stations servicing the links, and assigns a portion of the available frequencies to form frequency hopping patterns for the links based on system performance parameters.

15. The system of claim 14, wherein the dynamic frequency hopping management device determines available frequencies corresponding to a selected link of the links, includes unassigned frequencies in the available frequencies, and includes frequencies assigned to currently active links in the available frequencies if the selected link is not included in link neighborhoods of the currently active links.

16. The system of claim 15, wherein the dynamic frequency hopping management device includes frequencies assigned to each of the currently active links if a performance of each of the currently active links for the assigned frequencies falls below a threshold.

17. The system of claim 14, wherein a base station neighborhood of the base station neighborhoods corresponds to a base station, the base station neighborhood including base stations that service links whose link neighborhoods include the selected link.

18. The system of claim 14, wherein the dynamic frequency hopping management device generates a link quality for each frequency of a frequency hopping pattern of a link, identifies a first number of replacement frequencies of the frequency hopping pattern that have link qualities that are less than a link quality threshold, marks the link if the first number exceeds a marking threshold, and assigns the replacement frequencies to links that are marked.

19. The system of claim 18, wherein the dynamic frequency hopping management device selects randomly a second number of the available frequencies that correspond to the link, each of the second number of the available frequencies having a link quality that exceeds an assigning threshold, the second number being the same as the first number, the dynamic frequency hopping management device assigning the second number of selected available frequencies to replace the replaceable frequencies.

20. The system of claim 18, wherein the dynamic frequency hopping management device selects a second number of the available frequencies that correspond to the link, have largest link qualities and exceed the link quality threshold, the second number being the same as the first number, the dynamic frequency hopping management device assigning the second number of the selected available frequencies to replace the replaceable frequencies.

21. The system of claim 18, wherein the link quality includes signal-interference-plus-noise-ratio (SINR), block error rate or bit error rate quality.

22. The system of claim 14, wherein the dynamic frequency hopping management device:

selects ones of the available frequencies that;

a) correspond to the link; and

b) one of optimize an estimated performance of the link or optimize estimated performances of one or more other links serviced by a base station servicing the link; and

assigns the selected ones of the available frequencies to a new frequency pattern for the link.

23. The system of claim 22, wherein the optimum estimated performance includes one or more of highest estimated throughput, an estimated throughput that exceeds a throughput threshold, a predetermined level of estimated quality of service, a maximum number of terminals serviced at a set level of estimated quality, or an estimated error rate less than a error rate threshold.

24. The system of claim 14, wherein the dynamic frequency hopping management device receives a token, selects ones of the available frequencies that correspond to the link and optimize an estimated communication system performance, and assigns the selected ones of the available frequencies to a new frequency pattern for the link.

25. The system of claim 14, wherein the dynamic frequency hopping management device receives information from all base station of the communication system, selects ones of the available frequencies that optimize an estimated communication system performance, and assigns the selected ones of the available frequencies to new frequency patterns to the links.

26. The system of claim 14, wherein the communication system uses time division multiplexing (TDM), the dynamic frequency hopping management device identifying available slots corresponding to the identified available frequencies, assigning a combination of the available slots and the available frequencies based on system performance parameters.