Using the repetition of an erasure indicator bit to enhance a power control command during handoff
View Patent ↗A wireless communication network ( 20 ) includes a power control technique that includes repeating an erasure indicator bit in a transmission from a mobile station ( 22 ) to a base station ( 24, 30, 36 ). The repeated erasure indicator bit is transmitted on the uplink to each base station. The base station then uses the majority rule of those repeated erasure indicator bits to adjust its transmit power. It results in a desired power control command corresponding to the quality of a downlink between a base station ( 24, 30, 36 ) and the mobile station ( 22 ). A disclosed example includes using the repeated error indicator bit for deciding whether a recent frame should be considered an erasure. If so, the base station increases power on the downlink forward channel. If not, the base station decreases the transmit power on the downlink forward channel. A disclosed example includes alternative power control adjustment techniques, depending on the recent history of the quality of the downlink.
1. A method of communicating, comprising
using a repeated erasure indicator bit that is repeated a plurality of times within a single frame as an indication of a power control command from a mobile station;
wherein the repeated erasure indicator bit has a first value when a previous frame received at the mobile station comprises an erasure and the repeated erasure indicator bit has a second, different value when a previous frame was successfully received at the mobile station;
receiving the repeated erasure indicator bit; and
determining whether a number of the received bits having the first value exceeds a number of the received bits having the second value.
2. The method of claim 1 , comprising
receiving the repeated erasure indicator bit; and
adjusting a forward link transmit power level in a manner corresponding to a value of at least a majority of the received repeated erasure indicator bit.
3. The method of claim 2 , comprising
automatically increasing the transmit power level using a predetermined increment when the repeated erasure indicator bit indicates a command for increased transmit power.
4. The method of claim 2 , comprising
determining whether using a predetermined increment for increasing the transmit power level will result in the transmit power level exceeding a maximum level; and
increasing the transmit power level by the predetermined increment if using the predetermined increment will not result in the transmit power level exceeding the maximum level; or
setting the transmit power level to the maximum level if using the predetermined increment will result in the transmit power level exceeding the maximum level.
5. The method of claim 2 , comprising
automatically decreasing the transmit power level using a predetermined amount when the repeated erasure indicator bit indicates a command for decreased transmit power.
6. The method of claim 5 , comprising
determining a number of consecutive frames in which the repeated erasure indicator bit indicates a command for decreased transmit power; and
decreasing the transmit power by the predetermined amount when the determined number is below a threshold; or
decreasing the transmit power by the predetermined amount multiplied by a factor comprising the determined number when the determined number exceeds the threshold.
7. The method of claim 6 , wherein the factor comprises the square root of the determined number.
8. The method of claim 6 , wherein the threshold comprises two consecutive frames.
9. The method of claim 2 , comprising
determining whether using a predetermined amount for decreasing the transmit power level will result in a transmit power level that is below a lock threshold; and
decreasing the transmit power level by the predetermined amount if decreasing the transmit power level by the predetermined amount will result in a transmit power level exceeding the lock threshold; or
setting the transmit power level to the lock threshold level if decreasing the transmit power level by the predetermined amount will result in a transmit power level below the lock threshold.
10. The method of claim 1 , wherein the erasure indicator bit is repeated a number of times corresponding to an entire set of power control groups within the frame.
11. The method of claim 1 , wherein the erasure indicator bit is repeated 16 times within the frame.
12. The method of claim 1 , comprising
using the repeated erasure indicator bit during soft handoff.
13. The method of claim 1 , wherein the repeated erasure indicator bit first value is 1 and the second value is 0.
14. The method of claim 13 , wherein the repeated erasure indicator bit value of 1 corresponds to a power control command for increasing transmit power on a forward link and the value of 0 corresponds to a power control command for decreasing the transmit power.
15. The method of claim 13 , comprising
increasing a forward link transmit power when the number of the received bits having the value 1 exceeds the number having the value 0; or
decreasing the forward link transmit power when the number of the received bits having the value 0 exceeds the number having the value 1.