Spread-spectrum carrier transmission power control in wireless telecommunications systems

• US 6,628,637 B1
• Filed: 12/15/1999
• Issued: 09/30/2003
• Est. Priority Date: 12/15/1999
• Status: Expired due to Term

• Current Assignee: Apple Inc.
• Original Assignee: Nortel Networks Limited (Nortel Networks Corporation)
• Inventors: Li, Huan, Yang, Ping
• Primary Examiner(s): Bost, Dwayne
• Assistant Examiner(s): GELIN, JEAN ALLAND
• Application Number:
  US09/464,667
• Time in Patent Office: 1,385 Days
• Field of Search: 455/69, 455/70, 455/522, 455/63, 455/453, 455/436, 455/450, 455/438, 455/439, 370/252, 370/335, 370/342, 370/230, 370/329, 370/330, 370/331, 370/332, 370/333, 370/441, 370/445, 370/447, 370/320, 370/328, 370/318
• US Class Current: 370/342
• CPC Class Codes: H04W 48/06 based on traffic conditions
• CPC Class Codes: H04W 52/12 Outer and inner loops
• CPC Class Codes: H04W 52/228 using past power values or information
• CPC Class Codes: H04W 52/285 taking into account the mobility of the user
• CPC Class Codes: H04W 52/34 TPC management, i.e. sharing limited amount of power among users or channels or data types, e.g. cell loading

Abstract

A new call blocking threshold of one or more BTS forward links is adjusted to compensate for variation in traffic demand and, optionally, user mobility as well. Anticipated traffic demand from new calls and user mobility are derived from operational measurement data obtained and stored in a management and control system. The new call blocking threshold is adjusted with a frequency relating to the rate of change in traffic demand or user mobility.

Claims

1. A method of enhancing the grade of service of one or more CDMA wireless links in a wireless telecommunications system, comprising:

determining the total transmission power T_x of one or more wireless transmission forward links;

setting a transmission power T_x threshold T_Th for new calls transmitted on one or more of the forward links;

blocking one or more new calls directed to one or more of the forward links of the total transmission power T_x from exceeding the transmission power threshold T_Th;

selecting one or more desired maximum new call blocking probabilities P_Bmax for one or more of the forward links; and

adjusting the transmission power threshold T_Th for one or more of the forward links to correspond to the desired maximum new call blocking probability P_Bmax.

2. The method of claim 1, further comprising:

determining the user mobility h within one or more sectors serviced by one or more forward links; and

wherein the step of adjusting the transmission power threshold T_Th for one or more forward links is completed with reference to both new call traffic and the user mobility h within one or more sectors serviced by one or more of the forward links.

3. The method of claim 1, wherein the step of adjusting the transmission power threshold T_Th is completed with reference to operational measurement data for one or more sectors serviced by one or more of the forward links.

4. The method of claim 2, wherein the step of adjusting the transmission power threshold T_Th for one or more forward links is completed with reference to operational measurement data for one or more sectors serviced by one or more of the forward links.

5. The method of claim 1, further comprising:

determining the number of new calls blocked for one or more of the forward links during a preceding time interval;

estimating the new call blocking probability P_B(k+1) for one or more of the forward links for a subsequent time interval with reference to the number of new calls blocked during the preceding time interval; and

adjusting the transmission power threshold T_Th for one or more of the forward links if the estimated new call blocking probability P_B(k+1) is not equivalent to the desired maximum new call blocking probability P_Bmax.

6. The method of claim 2, further comprising:

determining the mobility of users for one or more sectors serviced by one or more of the forward links during a preceding time interval;

estimating the user mobility for one or more sectors serviced by one or more of the forward links for a subsequent time interval with reference to the user mobility determined for the preceding time interval; and

adjusting the transmission power threshold T_Th for one or more of the forward links. with reference, at least in part, to the user mobility estimated for the subsequent time interval.

7. The method of claim 1, further comprising:

determining a new call blocking value representing the portion of new calls blocked from transmission over one or more of the forward links in a prior time interval;

comparing the determined new call blocking value to the desired maximum new call blocking probability P_Bmax; and

adjusting the transmission power T_x threshold T_Th of one or more of the forward links in relation to whether the determined new call blocking value is less than or greater than the desired maximum new call blocking probability.

8. The method of claim 2, further comprising:

determining a user mobility h value representing at least in part the number of handoffs or hand-overs in one or more sectors serviced by one or more of the forward links in a prior time interval; and

adjusting the transmission power T_x threshold T_Th of one or more of the forward links in relation to the determined mobility value h.

9. The method of claim 7, further comprising:

monitoring user traffic in one or more sectors serviced by one or more of the forward links; and

varying the frequency of adjusting the transmission power T_x threshold T_Th of one or more of the forward links servicing one or more of the monitored sectors in relation to whether the monitored user traffic is increasing or decreasing.

10. The method of claim 8, further comprising varying the frequency of adjusting the transmission power T_x threshold T_Th of one or more of the forward links in relation to whether the monitored user mobility h is increasing or decreasing.

11. The method of claim 9, further comprising varying the frequency of adjusting the transmission power T_x threshold T_Th of one or more of the forward links with reference to one or both of an upper and lower threshold rate of change in the monitored user traffic.

12. The method of claim 10, further comprising varying the frequency of adjusting the transmission power T_x threshold T_Th of one or more of the forward links with reference to one or both of an upper and lower threshold rate of change in the monitored user mobility.

13. The method of claim 7, further comprising:

collecting and storing in memory operational measurement data including representations of new calls blocked from transmission on one or more of the forward links; and

wherein the new call blocking value is determined with reference to the operational measurement data.

14. The method of claim 8, further comprising:

collecting and storing in memory operational measurement data including representations of user mobility within one or more sectors serviced by one or more of the forward links; and

wherein the user mobility h value is determined with reference to the operational measurement data.

15. The method of claim 13, wherein the operational measurement data is collected and stored for a time interval and wherein the new call blocking value is determined from a prior time interval in which the operational measurement data is collected and stored.

16. The method of claim 14, wherein the operational measurement data is collected and stored for a time interval and wherein the user mobility h value is determined from a prior time interval in which the operational measurement data is collected and stored.

17. A system for enhancing the grade of service of one or more CDMA wireless links in a wireless telecommunications system, comprising:

monitoring means for determining the total transmission power T_x of one or more wireless transmission forward links;

means for setting a transmission power T_x threshold T_Th for new calls transmitted on one or more of the forward links;

means for blocking one or more new calls directed to one or more of the forward links if the total transmission power T_x exceeds the transmission power threshold T_Th;

means for establishing one or more desired maximum new call blocking probabilities P_Bmax for one or more of the forward links; and

means for adjusting the transmission power threshold T_Th for one or more of the forward links in relation to the desired maximum new call blocking probability P_Bmax.

18. The system of claim 17, further comprising:

means for determining the user mobility h within one or more sectors serviced by one or more forward links; and

wherein the means for adjusting the transmission power threshold T_Th for one or more forward links completes the adjustment with reference to both new call traffic and the user mobility h within one or more sectors serviced by one or more of the forward links.

19. The system of claim 17, wherein the means for adjusting the transmission power threshold T_Th completes the adjustment with reference to operational measurement data for one or more sectors serviced by one or more of the forward links.

20. The system of claim 18, further comprising means for adjusting the transmission power threshold T_Th for one or more forward links with reference to operational measurement data for one or more sectors serviced by one or more of the forward links.

21. The system of claim 17, further comprising:

means for determining the number of new calls blocked for one or more of the forward links during a preceding time interval;

means for estimating the new call blocking probability P_B(k+1) for one or more of the forward links for a subsequent time interval with reference to the number of new calls blocked during the preceding time interval; and

means for adjusting the transmission power threshold T_Th for one or more of the forward links if the estimated new call blocking probability P_B(k+1) is not equivalent to the desired maximum new call blocking probability P_Bmax.

22. The system of claim 18, further comprising:

means for determining the mobility of users for one or more sectors serviced by one or more of the forward links during a preceding time interval;

means for estimating the user mobility for one or more sectors serviced by one or more of the forward links for a subsequent time interval with reference to the user mobility determined for the preceding time interval; and

means for adjusting the transmission power threshold T_Th for one or more of the forward links with reference at least in part to the user mobility estimated for the subsequent time interval.

23. The system of claim 17, further comprising:

means for determining a new call blocking value representing the portion of new calls blocked from transmission over one or more of the forward links in a prior time interval;

means for comparing the determined new call blocking value to the desired maximum new call blocking probability P_Bmax; and

means for adjusting the transmission power T_x threshold T_Th of one or more of the forward links in relation to whether the determined new call blocking value is less than or greater than the desired maximum new call blocking probability.

24. The system of claim 18, further comprising:

means for determining a user mobility h value representing at least in part the number of handoffs or hand-overs in one or more sectors serviced by one or more of the forward links in a prior time interval; and

means for adjusting the transmission power T_x threshold T_Th of one or more of the forward links in relation to the determined mobility value h.

25. The system of claim 23, further comprising:

means for monitoring user traffic in one or more sectors serviced by one or more of the forward links; and

means for varying the frequency of adjusting the transmission power T_x threshold T_Th of one or more of the forward links servicing one or more of the monitored sectors in relation to whether the monitored user traffic is increasing or decreasing.

26. The system of claim 24, further comprising means for varying the frequency of adjusting the transmission power T_x threshold T_Th of one or more of the forward links in relation to whether the monitored user mobility h is increasing or decreasing.

27. The system of claim 25, further comprising means for varying the frequency of adjusting the transmission power T_x threshold T_Th of one or more of the forward links with reference to one or both of an upper and lower threshold rate of change in the monitored user traffic.

28. The system of claim 26, further comprising means for varying the frequency of adjusting the transmission power T_x threshold T_Th of one or more of the forward links with reference to one or both of an upper and lower threshold rate of change in the monitored user mobility.

29. The system of claim 23, further comprising:

means for collecting and storing in memory operational measurement data including representations of new calls blocked from transmission on one or more of the forward links; and

means for determining the new call blocking value with reference to the operational measurement data.

30. The system of claim 24, further comprising:

means for collecting and storing in memory operational measurement data including representations of user mobility within one or more sectors serviced by one or more of the forward links; and

means for determining the user mobility h value is determined with reference to the operational measurement data.

31. The system of claim 29, wherein the operational measurement data is collected and stored by the data collecting and storing means for a time interval and wherein the new call blocking value is determined by the new call blocking value determining means from a prior time interval in which the operational measurement data is collected and stored.

32. The system of claim 30, wherein the operational measurement data is collected and stored by the data collecting and storing means for a time interval and wherein the user mobility h value is determined by the user mobility value determining means from a prior time interval in which the operational measurement data is collected and stored.

33. A method of adjusting the call blocking threshold of a forward link of a wireless telecommunications system, comprising:

determining a measured call blocking value related to a ratio of a number of calls made to a number of blocked calls on the forward link during one or more time intervals;

selecting a desired call blocking value representing a desired ratio of a number of calls made to a number of calls blocked on the forward link;

comparing the measured call blocking value to the desired call blocking value; and

adjusting the call blocking threshold of the forward link in relation to the comparison of the measured call blocking value and the desired call blocking value.

34. The method of claim 33, wherein the measured call blocking value is used to determine a measured grade of service value for one or more of the time intervals, the desired call blocking value is used to determine a desired grade of service, and the call blocking threshold is adjusted in relation to a comparison of the measured grade of service and the desired grade of service.

35. A method of setting a call blocking threshold of a CDMA forward link in a wireless telecommunications system, comprising:

(a) setting the call blocking threshold of the forward link at a first value during a first time interval;

(b) selecting a target grade of service for the forward link;

(c) obtaining and storing user traffic data and user mobility data during at least a portion of the first time interval for a sector serviced by the forward link;

(d) determining an actual grade of service for the forward link from the user traffic data and user mobility data during the first time interval;

(e) updating the call blocking threshold of the forward link for a second subsequent time interval to a second value that is lower than the first value if the actual grade of service exceeds the selected target grade of service and to a second value that is higher than the first value if the actual grade of service is less than the selected target grade of service;

(f) obtaining and storing user traffic data and user mobility data during at least a portion of the second time interval for the sector serviced by the forward link; and

(g) adjusting the duration of the second time interval if either or both of the user traffic data and user mobility data obtained during one or more preceding time intervals indicates an increase or decrease in the user traffic or user mobility.

36. The method of claim 35, wherein the user traffic data and the user mobility data are obtained with reference to operational measurement data.

37. The method of claim 35, further comprising:

a third time interval during which user traffic and user mobility data are obtained and stored; and

wherein the third time interval is adjusted in relation to whether either or both of the user traffic data and the user mobility data obtained for the first and second time intervals indicate an increase or decrease in user traffic or user mobility within the sector.

38. The method of claim 37, further comprising:

deriving user traffic data and user mobility data during at least a portion of the second time interval; and

wherein the third time interval is adjusted in relation to whether either or both of the user traffic data or the user mobility data indicates an increase or decrease in user traffic or user mobility within the sector during the second time interval as compared to the first time interval.

39. The method of claim 38, further comprising:

selecting a threshold value of user traffic rate change Δ

A_max;

determining the absolute value |Δ

A_1,2| of the difference between user traffic for the sector during the first and second time intervals; and

decreasing the duration of the third time interval if the value |Δ

A_1,2| is greater than the user traffic rate change threshold Δ

A_max.

40. The method of claim 38 or 39, further comprising:

selecting a threshold value of user traffic rate change Δ

A_min;

determining the absolute value of the difference between user traffic |Δ

A_1,2| for the sector during the first and second time intervals; and

increasing the duration of the third time interval if the value |Δ

A_1,2| is less than the user traffic rate change threshold Δ

A_min.

41. The method of claim 38, further comprising:

selecting a threshold value of user mobility rate change Δ

h_max;

determining the absolute value of the difference between user mobility |Δ

h_1,2| for the sector during the first and second time intervals; and

decreasing the duration of the third time interval if the value |Δ

h_1,2| is greater than the user traffic rate change threshold Δ

h_max.

42. The method of claim 38 or 41, further comprising:

selecting a threshold value of user mobility rate change Δ

h_min;

determining the absolute value of the difference between user mobility |Δ

h_1,2| for the sector during the first and second time intervals; and

increasing the duration of the third time interval if the value |Δ

h_1,2 | is less than the user traffic rate change threshold Δ

h_min.