System and method of determining standby time for mobile stations

• US 20070184827A1
• Filed: 07/28/2006
• Published: 08/09/2007
• Est. Priority Date: 07/29/2005
• Status: Active Grant

• Current Assignee: Malikie Innovations Limited (Key Patent Innovations Limited)
• Original Assignee: Blackberry Limited
• Inventors: Mallalieu, Jennifer, Jin, Xin, Shearer, Fiona
• Granted Patent: US 7,706,845 B2
• Time in Patent Office: Days
• US Class Current: 455/423
• CPC Class Codes: H04M 1/24 Arrangements for testing
• CPC Class Codes: H04W 52/0261 managing power supply demand, e.g. depending on battery level
• CPC Class Codes: Y02D 30/70 in wireless communication networks

Abstract

A method and system for determining standby time for a mobile station uses a battery simulator, a base station emulator, a computer to control the test equipment and MSUT for testing a mobile station. The computer includes a module for determining a radio off battery voltage, a module for deriving a battery capacity in dependence upon the radio off battery voltage, a module for measuring battery capacity usage in a predetermined time while the mobile station is in standby mode and a module for determining a standby time for the mobile station in dependence upon the battery capacity and the battery capacity usage, where the predetermined time is less than the standby time.

Claims

1. A method of determining standby time for a mobile station, the method comprising the steps of:

measuring average current while the mobile station is in standby mode;

determining available battery capacity of a battery in the mobile station; and

determining a standby time for the mobile station in dependence upon the available battery capacity and the average current consumption.

2. The method as claimed in claim 1, wherein the step of measuring the average current is performed over a predetermined time less than the standby time.

3. The method as claimed in claim 1, wherein the available battery capacity determined upon a radio off battery voltage.

4. The method as claimed in claim 2, further comprising the step of determining a radio off battery voltage, the available battery capacity determined upon a radio off battery voltage.

5. The method as claimed in claim 4, wherein the step of determining a radio off battery voltage comprises the steps of:

providing a simulated battery voltage at a first voltage value to the mobile station;

determining if the mobile station radio is on;

if the mobile station radio is on, decrementing the first voltage value to a next voltage value by a predetermined amount;

repeating until the mobile station radio is off the steps of;

re-determining if the mobile station radio is on; and

if the mobile station radio is on, decrementing the next voltage value; and

recording the radio off battery voltage

6. The method as claimed in claim 5, wherein the steps of determining a radio off battery voltage are repeated a plurality of times and the resulting voltage value is averaged to determine the radio off battery voltage.

7. The method as claimed in claim 6, further comprising the step of simulating the ESR effect of the battery while determining the radio off battery voltage.

8. The method as claimed in claim 7, wherein the step of measuring average current consumption includes the step of determining average transmit current by collecting a time span of current measurement data points comprising at least one complete transmit event and extracting the current measurement data points of the at least one complete transmit event relating to the time the transmitter is turned on;

and

setting the base station emulator to request the MSUT to register more frequently than the registration period to be tested.

9. The method as claimed in claim 8, further comprising the step of calculating the capacity used of each transmit event of the at least one complete transmit event.

10. The method as claimed in claim 9, wherein the steps of determining average transmit current are repeated to record a plurality of transmit measurements

11. The method as claimed in claim 10, further comprising the step of calculating an average capacity usage in each transmit event (Ctx) as:

$C_{\mathrm{tx}}=\left(\underset{j=1}{\overset{N}{\sum <br><br>}}<br><br>\left(C_j\right)\right)/N,$

where N is the total number of transmit events measured; and

calculating the average transmit current (i_tx) as;

i _tx =C _tx /T _tx

where T_tx is a registration interval.

12. The method as claimed in claim 11, wherein the step of determining average transmit current further comprises the step of triggering the simulator to start collecting current measurement data points when a transmit activity is detected and wherein the steps of triggering comprises the step of setting a threshold for current level exceeding the current consumption level for receiver only operation.

13. The method as claimed in claim 12, wherein the step of determining the standby time comprises the step of determining receive capacity usage and;

wherein the step of determining receive capacity usage comprises the steps of;

configuring the base station emulator to disable timer based registration and all other types registrations except the power up registration; and

measuring the receive current array of MSUT segment by segment using a sampling interval small enough to capture all current activities.

14. The method as claimed in claim 13, wherein the step of determining receive capacity usage further comprises the steps of:

record multiple receive current segments;

for each segment;

post processing the current measurement data array; and

calculating the mean current value of each receive segment;

calculating the mean (i_rx) over all the segments measured; and

determining the capacity used while in receive mode for 1 hour (hr) of MSUT operation.

15. The method as claimed in claim 14, wherein the capacity used for 1 hour by receive mode (C_rx—

<sub>in—

1 hr</sub>) is calculated by;

$C_{\mathrm{rx\_in}<br><br>\_<br><br>1<br><br>\text{\hspace{1em}<br><br>}<br><br>\mathrm{hr}}=\left(i_{\mathrm{rx}}*\left(1-t_{\mathrm{tx\_in}<br><br>\_<br><br>1<br><br>\text{\hspace{1em}<br><br>}<br><br>\mathrm{hr}}\right)\right)$ $\mathrm{where}$ $t_{\mathrm{tx\_in}<br><br>\_<br><br>1<br><br>\text{\hspace{1em}<br><br>}<br><br>\mathrm{hr}}=\left(\underset{j=1}{\overset{N}{\sum <br><br>}}<br><br>\left(t_j\right)\right)*\left(M/N\right);<br><br>$ $t_j=m*\mathrm{\Delta <br><br>}<br><br>\text{\hspace{1em}<br><br>}<br><br>t;<br><br>$

m is the last point of transmit activity; and

Δ

t is a sample interval;

the total capacity used by the MSUT in one hour is;

C_{1 hr}=C<sub>rx—

in—

1 hr</sub>+C<sub>tx—

in—

1 hr</sub>;

and the standby time in hours is calculated to be;

T_standby=(C_new−

C_cutoff)/(C_{1 hr})

where C_new−

C_cutoff is the capacity difference between a fully charged battery and the capacity at the cutoff voltage.

16. The method as claimed in claim 14, capacity used for 1 hour by receive mode (C_rx—

<sub>in—

1 hr</sub>) is calculated by;

C<sub>rx—

in—

1 hr</sub>=(i_rx*1 hr).

17. The method as claimed in claim 12, wherein the step of determining the standby time comprises the step of determining average receive current and wherein the step of determining average receive current comprises the steps of:

configuring the base station emulator to disable timer based registration and all other types registrations except the power up registration; and

measuring the receive current array of MSUT segment by segment using a sampling interval small enough to capture all current activities.

18. The method as claimed in claim 17, wherein the step of determining receive capacity usage further comprises the steps of:

record multiple receive current segments;

for each segment;

post processing the current measurement data array; and

calculating the mean current value of each receive segment; and

calculating the mean (i_rx) over all the segments measured.

19. The method as claimed in claim 18, wherein the standby time in hours is calculated to be:

T_standby=(C_new−

C_cutoff)/(i_tx+i_rx)

where Cnew−

Ccutoff is the capacity difference between a fully charged battery and the capacity at the cutoff voltage, and i_tx+i_rx is the total of the average transmit current and average receive current.

20. A system for determining standby time for a mobile station, the system comprising:

a battery simulator;

a base station emulator; and

a computer including a module for determining a radio off battery voltage, a module for deriving a battery capacity in dependence upon the radio off battery voltage, a module for measuring current while the mobile station is in standby mode and a module for determining a standby time for the mobile station in dependence upon they available battery capacity and average current, where the predetermined time is less than the standby time.

21. The system as claimed in claim 20, wherein the module for deriving average current includes a module for determining average transmit current.