Monitoring of CDMA load and frequency reuse based on reverse link signal-to-noise ratio

• US 6,356,531 B1
• Filed: 06/07/1999
• Issued: 03/12/2002
• Est. Priority Date: 06/07/1999
• Status: Expired due to Term

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Soliman, Samir S.
• Primary Examiner(s): Chin, Wellington
• Assistant Examiner(s): Harper, Kevin C.
• Application Number:
  US09/327,103
• Time in Patent Office: 1,009 Days
• Field of Search: 370/241, 370/254, 370/320, 370/335, 370/342, 370/441, 370/479, 455/423, 455/447, 455/450, 455/501, 455/504, 455/522, 455/67.1, 455/67.3
• US Class Current: 370/241
• CPC Class Codes: H04W 16/04 Traffic adaptive resource partitioning
• CPC Class Codes: Y02D 30/70 in wireless communication networks

Abstract

A system and method for monitoring the load on a CDMA communication system having a base station and a plurality of users. A measure of voice activity in the communication system is determined, and a current value of frequency reuse efficiency equal to an initial value of frequency reuse efficiency is provided. A power determination is made according to the measured voice activity and the current value of frequency reuse efficiency. The current value of frequency reuse efficiency is updated using the power determination to provide a new current value of frequency reuse efficiency. The power determination and the update of the frequency reuse efficiency are iteratively repeated until convergence to provide a converged value of frequency reuse efficiency. The load on the communication system is then determined according to the converged frequency reuse efficiency value.

Claims

1. A method for monitoring the load on a CDMA communication system, comprising the steps of:

(a) determining a measure of voice activity in the communication system;

(b) providing a current value of frequency reuse efficiency equal to an initial value of frequency reuse efficiency;

(c) making a power determination according to the determined voice activity and the current value of frequency reuse efficiency;

(d) using the power determination to update the current value of frequency reuse efficiency to provide a new current value of frequency reuse efficiency;

(e) repeating steps (c) and (d) until convergence to provide a converged frequency reuse efficiency value; and

(f) determining the load on the communication system in accordance with the converged frequency reuse efficiency value.

2. The method of claim 1, wherein the communication system comprises a base station that services a plurality of mobile stations.

3. The method of claim 2, wherein step (c) comprises the steps of:

(i) determining a total received power (P_t) associated with a kth sector; and

(ii) calculating a power value (P_cdma(n)) in accordance with the total received power (P_t) associated with the kth sector, the determined voice activity and a current value of frequency reuse efficiency associated with the kth sector (F_k(n)).

4. The method of claim 3, wherein step (d) comprises the step of calculating a new current value of frequency reuse efficiency associated with the kth sector F_k(n+1) using the power value (P_cdma(n)) and the total received power (P_t) associated with the kth sector.

5. The method of claim 4, wherein the new current value of frequency reuse efficiency F_k(n+1) is determined in step (d) in accordance with the following equation:

$F_k<br><br>\left(n+1\right)=\frac{P<br><br>\left(n\right)}{P_t-N_o<br><br>W}$

wherein N_oW represents background noise received at the base station.

6. The method of claim 5, wherein step (e) comprises the step of repeating steps (c) and (d) until a difference between the new current value of frequency reuse efficiency F_k(n+1) and the current value of frequency reuse efficiency F_k(n) is less than a predetermined threshold.

7. The method of claim 6, wherein step (e) comprises the step of repeating steps (c) and (d) until the new current value of frequency reuse efficiency F_k(n+1) and the current value of frequency reuse efficiency F_k(n) are equal.

8. The method of claim 6, wherein step (f) comprises determining a load (L) on the communication system in accordance with the following equation:

$L=\frac{1}{F_k}<br><br>\underset{i=1}{\overset{N}{\sum <br><br>}}<br><br>\text{\hspace{1em}<br><br>}<br><br>\frac{v_i<br><br>x_i}{W/R_i+\frac{1}{F_k}<br><br>v_i<br><br>x_i}$

where F_k is the converged frequency reuse efficiency value, v_i corresponds to the voice activity measured in step (a), R_i is the data rate of a user of the communication system, and x_i is the energy per bit to noise power spectral density of a reverse traffic channel in the communication system.

9. The method of claim 1, wherein the communication system includes a sector, and step (f) comprises determining the load of the sector according to the converged frequency reuse efficiency value.

10. The method of claim 9, further comprising the step of controlling the communication system according to the sector loading.

11. The method of claim 1, further comprising the step of controlling the admission of new users to the communication system according to the load determined in step (f).

12. The method of claim 1, further comprising the step of collecting peak hour activities according to the load value determined in step (f).

13. The method of claim 1, wherein the initial value of frequency reuse efficiency is approximately 0.66.

14. A system for monitoring the load on a CDMA communication system, comprising:

(a) a value representing voice activity in the communication system;

(b) a current value of frequency reuse efficiency equal to an initial value of frequency reuse efficiency;

(c) a value representing system power determined according to the voice activity and the current value of frequency reuse efficiency;

(d) a new current value of frequency reuse efficiency provided by updating the current value of the frequency reuse efficiency in accordance with the value representing system power;

(e) a converged frequency reuse efficiency value determined by performing iterative operations on the determined system power and the current value of frequency reuse efficiency; and

(f) a controller that determines the load on the communication system according to the converged frequency reuse efficiency value.

15. A system for monitoring the load on a CDMA communication system, comprising:

(a) means for determining a measure of voice activity in the communication system;

(b) means for providing a current value of frequency reuse efficiency equal to an initial value of frequency reuse efficiency;

(c) means for making a power determination according to the determined voice activity and the current value of frequency reuse efficiency;

(d) means for using the power determination to update the current value of frequency reuse efficiency to provide a new current value of the frequency reuse efficiency;

(e) means for providing a converged frequency reuse efficiency value by performing iterative operations on the determined system power and the current value of frequency reuse efficiency; and

(f) means for determining the load on the communication system according to the converged frequency reuse value.