Method and apparatus for initiating a reverse link intergenerational handoff in a CDMA communication system

Apparatus in a subject mobile station for initiating reverse-link portions of handoffs between a serving base station and a target base station in a CDMA communication system having a plurality of base stations in communication with at least one mobile station, comprising:

• a) a pilot strength reporting block for sending a pilot strength measurement message (PSMM) to the serving base station when a first signal strength-related parameter associated with the target base station is greater than a threshold parameter “T_Add”;
• and
• b) a reverse link handoff control block configured to implement a reverse link intergenerational hard handoff when, after the serving base station transmits an intergenerational handoff direction message to the mobile station, a second parameter describing a signal strength-related characteristic of a signal from the serving base station is less than or equal to a sum of a current value of the first parameter and an offset;
• wherein the reverse link intergenerational hard handoff comprises a portion of an intergenerational handoff, distinct from a forward link portion, and includes terminating signal transmissions from the mobile station to the serving base station and subsequently initiating signal transmission from the mobile station to the target base station.

A computer program executable on a computing device, wherein the program is capable of directing performance of a reverse link handoff between a serving base station and a target base station that has been directed by a CDMA communication system having a plurality of base stations in communication with at least one mobile station, wherein each base station transmits at least one associated and corresponding pilot channel that uniquely identifies the base station, comprising:

• a) a first set of instructions for monitoring, after the subject mobile station has been directed to initiate the handoff to the target base station, a first signal strength-related parameter reflective of a signal received by the subject mobile station from the serving base station;
• b) a second set of instructions for monitoring, after the subject mobile station has been directed to initiate the handoff to the target base station, a second signal strength-related parameter reflective of a signal received by the subject mobile station from the target base station;
• c) a third set of instructions for determining if the first parameter is less than or equal to a sum of the second parameter and an offset;
• and
• d) a fourth set of instructions for initiating the reverse link handoff between the serving and target base stations if the first parameter is less than or equal to the sum of the second parameter and the offset;
• wherein the reverse link handoff comprises a reverse link portion of a complete handoff, and wherein the reverse link portion includes terminating signal transmissions from the mobile station to the serving base station and subsequently initiating signal transmission from the mobile station to the target base station, and wherein the reverse link portion is distinct from a forward link portion of the complete handoff.

A method of controlling completion of a handoff between a serving base station and a target base station in a CDMA communication system having a plurality of base stations in communication with at least one mobile station, wherein each base station transmits at least one associated and corresponding pilot channel that uniquely identifies the base station, comprising:

• a) first receiving, at a subject mobile station, a message from the serving base station directing performance of a handoff to the target base station;
• and thereafter
• b) monitoring a first signal strength-related parameter reflective of a signal received by the subject mobile station from the serving base station;
• c) monitoring a second signal strength-related parameter reflective of a signal received by the subject mobile station from the target base station;
• d) comparing current values of the first parameter to corresponding values of the second parameter;
• e) returning to step (b) if a current value of the first parameter is not less than a sum of an offset plus a corresponding current value of the second parameter;
• and
• f) initiating a reverse link portion of the handoff between the serving and target base stations if the current value of the first parameter is less than a sum of an offset plus the corresponding current value of the second parameter;
• wherein the reverse link portion of the handoff includes terminating signal transmissions from the mobile station to the serving base station and subsequently initiating signal transmission from the mobile station to the target base station, and wherein the reverse link portion is distinct from a forward link portion of the handoff.