System and method for variable reassignment of transmission channels

• US 6,442,151 B1
• Filed: 04/06/1999
• Issued: 08/27/2002
• Est. Priority Date: 04/06/1999
• Status: Expired due to Fees

• Current Assignee: Ericsson, Inc. (Telefonaktiebolaget LM Ericsson)
• Original Assignee: Ericsson, Inc. (Telefonaktiebolaget LM Ericsson)
• Inventors: Hʼmimy, Hossam H., Shah, Ali R.
• Primary Examiner(s): Hunter, Daniel
• Assistant Examiner(s): Harry, Andrew T
• Application Number:
  US09/287,140
• Time in Patent Office: 1,239 Days
• Field of Search: 455/62, 455/450, 455/452, 455/509, 455/512, 455/513, 370/329, 370/330, 370/331, 370/332, 370/333
• US Class Current: 370/333
• CPC Class Codes: H04W 36/06 Reselecting a communication resource in the serving access point
• CPC Class Codes: H04W 36/30 by measured or perceived connection quality data
• CPC Class Codes: H04W 72/541 using the level of interference
• CPC Class Codes: H04W 72/542 using measured or perceived quality

Abstract

A method of assigning a channel to a service in a wireless communications network based on interferences levels and channel quality. Channels are preassigned and then reassigned using an algorithm that assigns a channel to a service based on uplink interference and channel quality measurements. Reassignment can be achieved in one processing pass, rather than requiring multiple iterations.

Claims

1. In a wireless communications network having a plurality of channels for assignment to service, a method of assigning a channel to a service comprising the steps of:

preassigning a first channel to the service, said first channel having an interference level less than a predetermined blocking threshold;

monitoring the channel quality and interference level of the first channel; and

reassigning the service to a second channel based on the interference level and channel quality of the first channel.

2. The method of claim 1 wherein the step of reassigning the service to a second channel is performed using variable reassignment.

3. The method of claim 1 wherein the step of preassigning a first channel to the service is preceded by the steps of:

classifying all channels in the network into bands of interference according to measured levels of interference; and

classifying all channels in the network into categories of channel quality according to measured levels of channel quality.

4. The method of claim 3 further comprising the step of storing the bands of interference and categories of channel quality into a configuration defining a rule table.

5. The method of claim 4 wherein the step of reassigning the service to a second channel is performed using said rule table.

6. The method of claim 1 wherein the step of reassigning the service to a second channel is performed so that the lower the quality measurement of the first channel the lower the interference level of the second channel.

7. The method of claim 1 further comprising the steps of:

segregating channels in the network into some number, represented as n+1, of interference bands, in order from a best interference band, represented as I¹, to a worst interference band, represented as Iⁿ⁺¹, based on measured levels of interference for channels in the network; and

segregating channels in the network into some number, represented as m+1, of categories of channel quality in order from a lowest quality category, represented as Q¹, to a highest quality category, represented as Q^m+1.

8. The method of claim 6 wherein the step of reassigning the service is performed so that service is handed-off if the channel quality measurement of the first channel is in band Q¹.

9. The method of claim 6 wherein the step of reassigning the service is performed so that service is dropped if the channel quality of the first channel is in band Q¹.

10. The method of claim 6 wherein the step of reassigning the service is performed so that the second channel is within interference band I¹.

11. The method of claim 6 wherein the step of reassigning the service is performed so that for a first channel having a channel quality category Q^j and an interference band I^k, where j+k=n+2 and n>

m, the second channel is within interference band I<sup>(n−

m)+1</sup>.

12. The method of claim 6, wherein the step of reassigning the service is performed so that for a first channel having a channel quality category Q^j and an interference band Iⁿ⁻

p and n>

m, the second channel is within interference band I<sup>[(n−

m)+(j−

2)+p]+1</sup>.

13. The method of claim 1 wherein the step of monitoring channel quality is performed so the Bit Error Rate (BER) of the first channel is determined.

14. The method of claim 1 wherein the step of monitoring channel quality is performed so that the carrier-to-interference (C/I) ratio of the first channel is determined.

15. The method of claim 1 wherein the step of preassigning as first channel is performed by selecting the first available channel with the highest interference level less than the predetermined blocking threshold.

17. The method of claim 15 further comprising the step of storing the interference bands and categories of channel quality into a configuration defining a rule table.

19. The method of claim 15 further comprising the step of dropping the service when the channel quality category of the first channel is unacceptable for the network.

20. The method of claim 15 further comprising the step of handing off the service when the channel quality category of the first channel is unacceptable for the network.

22. The device of claim 20 wherein said algorithm resides in a base station controller of said wireless communications network.

23. The device of claim 20 wherein said algorithm resides in a base station of said wireless communications network.

24. The device of claim 20 wherein said algorithm further comprises a segregation function for classifying said plurality of transmission channels according to channel quality.

25. The device of claim 23 wherein said segregation function is adapted to create categories of channel quality.

26. The device of claim 24 wherein said segregation function is adapted to classify said plurality of transmission channels according to level of interference.

27. The device of claim 23 wherein said segregation function is adapted to create bands of interference.

28. The device of claim 26 wherein said segregation function is adapted to create a rule table containing a configuration of said categories of channel quality and bands of interference.

16. In a wireless communications network where an incoming request for service can be assigned to any one of a plurality of transmission channels, the interference levels of said plurality of transmission channels being less than a predetermined interference threshold, a method of assigning a channel to service comprising the steps of:

determining the interference of all of said plurality of transmission channels in the network;

measuring the channel quality of all of said plurality of transmission channels in the network;

segregating the plurality of transmission channels into interference bands according to levels of interference;

segregating the plurality of transmission channels into categories of channel quality according to levels of channel quality;

preassigning a first channel to an incoming request for service;

measuring the channel quality of the first channel; and

reassigning the service from the first channel to a second channel when the channel quality of the first channel falls below acceptable levels for the network, the interference band of the second channel selected using variable reassignment.

18. The method of claim 16 wherein the rule table is used in performing the step of reassigning the service from the first channel to a second channel.

21. In a wireless communications network having a plurality of transmission channels, an device containing an algorithm for assigning transmission channels to service, said algorithm comprising:

a discrimination function adapted to determine the interference and channel quality of transmission channels in the network;

a preassignment function adapted to preassign a first transmission channel with an interference level less than a predetermined blocking threshold of interference to the service;

a monitoring function adapted to continually monitor the channel quality of the preassigned transmission channel; and

a variable reassignment function adapted to reassign a second transmission channel to the service when the monitored levels of channel quality become unsatisfactory.