Method To Control The Effects Of Out-Of-Cell Interference In A Wireless Cellular System Using Over-The-Air Feedback Control

Abstract

A mobile terminal is controlled via over-the-air feedback so as to enable its data transmissions to be independently and successfully decoded at each of the base stations in its active set absent a transmit power limitation or data retransmission limit. Using the decoded data, the channel is re-estimated and the waveform received from the mobile terminal is reconstructed and subtracted from the total interference at each base station in the active set where decoding has been successful. As a result, transmissions from other mobile terminals, which have yet to be successfully decoded at such a base station, will experience a higher signal-to-noise ratio and thus an increased likelihood of being successfully decoded.

1 - 20 . (canceled) 
     
     
         21 . A mobile terminal, comprising:
 a receiver configured to receive commands from a plurality of base stations; and   a transmitter configured to:
 send, when the a mobile terminal is in handoff status, data packets to the plurality of base stations in the mobile terminal's active set of base stations, the active set including a serving base station and at least one non-serving base station; and 
 increase the transmit power of the transmitter, in response to the receiver receiving a command to increase the transmit power from any of the base stations, unless the transmit power is at its maximum power or the transmit power exceeds a power targeted by the serving base station by a predetermined amount. 
   
     
     
         22 . The mobile terminal of  claim 21  wherein the transmit power is increased by a predetermined up-step. 
     
     
         23 . The mobile terminal of  claim 21  wherein:
 in the event that:
 the transmit power is at its maximum power, or the transmit power exceeds a power targeted by the serving base station by a predetermined amount, and 
 the mobile terminal receives a command to increase its transmit power from any of the base stations in the active set, 
 
 the transmitter is configured to increase or decrease the transmit power only in response to commands received from the serving base station. 
 
     
     
         24 . The mobile terminal of  claim 21  wherein the transmitter is configured to increase the transmit power only if the receiver determines the received command is determined to be reliable. 
     
     
         25 . The mobile terminal of  claim 24  wherein the receiver determines that the command to increase the transmit power is reliable on the condition that a power of the received command to increase the power is greater than a predetermined threshold. 
     
     
         26 . A mobile terminal, comprising:
 a receiver configured to receive commands from a plurality of base stations; and   a transmitter configured to:
 send, when the mobile terminal is in handoff status, data packets to a plurality of base stations in an active set of base stations, the active set including a serving base station and at least one non-serving base station; and 
 increase a transmit power in response to the receiver receiving a negative acknowledgment (NACK) of a successful decoding of a given packet received from any of the base stations at the end of that packet's retransmission limit, unless the transmit power is at its maximum power or the transmit power exceeds a power targeted by the serving base station by a predetermined amount. 
   
     
     
         27 . The mobile terminal of  claim 26  wherein the transmitter is configured to increase the transmit power by a predetermined up-step. 
     
     
         28 . The mobile terminal of  claim 26  wherein:
 if
 the transmit power is at its maximum power or if the transmit power exceeds a power targeted by the serving base station by a predetermined amount, and 
 the receiver receives from any of the base stations in the active set a command to increase the transmit power, 
 
 then for a subsequent data transmission the transmitter is configured to increase the transmit power only if the receiver receives a NACK from the serving base station and to decrease the transmit power if the receiver receives an ACK from the serving base station. 
 
     
     
         29 . The mobile terminal of  claim 26  wherein the transmitter is configured to increase the transmit power only if the receiver determines a NACK received from any of the base stations in the active set is reliable. 
     
     
         30 . The mobile terminal of  claim 26  wherein the receiver determines the NACK is reliable by comparing a power of the received NACK with a predetermined threshold. 
     
     
         31 . A method for interference management in a wireless communication system, the method comprising:
 at a mobile terminal in handoff status, sending data packets to a plurality of base stations in the mobile terminal's active set of base stations, the active set including a serving base station and at least one non-serving base station; and   in response to receiving a command to increase the transmit power from any of the base stations in the active set, increasing the mobile terminal's transmit power, unless the transmit power is at its maximum power or the transmit power exceeds a power targeted by the serving base station by a predetermined amount, and   
     
     
         32 . The method of  claim 31  wherein the mobile terminal's transmit power is increased by a predetermined up-step. 
     
     
         33 . The method of  claim 31  wherein
 if
 the transmit power is at its maximum power or if the transmit power exceeds a power targeted by the serving base station by a predetermined amount, and 
 the mobile terminal receives a command to increase its transmit power from any of the base stations in the active set, 
 
 then controlling the transmit power up or down only in response to commands received from the serving base station. 
 
     
     
         34 . The method of  claim 31  further comprising determining the reliability of a received command to increase the transmit power, and increasing the transmit power only if the received command is determined to be reliable. 
     
     
         35 . The method of  claim 34  wherein the command to increase the transmit power is determined to be reliable if a power of the received command to increase the power is greater than a predetermined threshold. 
     
     
         36 . A method for interference management in a wireless communication system comprising:
 at a mobile terminal in handoff status, sending data packets to a plurality of base stations in its active set of base stations, the active set including a serving base station and at least one non-serving base station; and   in response to receiving a negative acknowledgment (NACK) of a successful decoding of the packet from any of the base stations in the active set at the end of a given packet's retransmission limit, increasing the mobile terminal's transmit power unless the transmit power is at its maximum power or the transmit power exceeds a power targeted by the serving base station by a predetermined amount.   
     
     
         37 . The method of  claim 36  wherein the mobile terminal's transmit power is increased by a predetermined up-step. 
     
     
         38 . The method of  claim 36  wherein:
 if
 the transmit power is at its maximum power or if the transmit power exceeds a power targeted by the serving base station by a predetermined amount, and 
 the mobile terminal receives a command to increase its transmit power from any of the base stations in the active set, 
 
 then for a subsequent data transmission the mobile terminal increases its transmit power only if it receives a NACK from the serving base station and decreases its transmit power if it receives an ACK from the serving base station. 
 
     
     
         39 . The method of  claim 36  further comprising determining the reliability of a received NACK from any of the base stations in the active set, and increasing the transmit power only if the received NACK is determined to be reliable. 
     
     
         40 . The method of  claim 36  wherein the NACK is determined to be reliable by comparing a power of the received NACK with a predetermined threshold.