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

An apparatus for initiating reverse link portions of handoffs that have previously been directed 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) mobile station transmission control facilities configured to send a pilot strength measurement message to the serving base station, and to add the target base station to an active set when a first parameter, Ec/Io, associated with the target base station is greater than a threshold parameter T_Add;
• and
• b) a mobile station handoff control module configured to initiate a reverse link intergenerational hard handoff as the reverse link portion of a previously directed intergenerational handoff when second parameter, Eb/Nt, associated with the serving base station is less than or equal to a sum of a third parameter, Eb/Nt, associated with the target base station and an offset,
• wherein the reverse link intergenerational hard handoff comprises the reverse link portion, distinct from a forward link portion, of the intergenerational handoff, and includes terminating transmissions from the mobile station to the serving base station and subsequently initiating transmissions from the mobile station to the target base station.

A computer program executable on a computing device, wherein the program is capable of directing initiation of reverse link portions of previously directed handoffs 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) a first set of instructions for monitoring a first parameter obtained from the serving base station, wherein the first parameter comprises the value of Eb/Nt that is associated with the serving base station;
• b) a second set of instructions for monitoring a second parameter obtained from the target base station, wherein the second parameter comprises the value Eb/Nt that is associated with the target base station;
• c) a third set of instructions for determining if the first parameter is less than or equal to the sum of the second parameter and an offset;
• and
• d) a fourth set of instructions for initiating a reverse link intergenerational hard handoff as the reverse link portion of a previously directed intergenerational 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 intergenerational hard handoff comprises the reverse link portion, distinct from a forward link portion, of the intergenerational handoff, and includes terminating transmissions from the mobile station to the serving base station and subsequently initiating transmissions from the mobile station to the target base station.

An apparatus for initiating a reverse link portion of a handoff that has previously been directed 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, and wherein the serving base station and the target base station operate in accordance to different generations of CDMA systems, comprising:

• a) means for sending a pilot signal measurement message (“PSMM”) to the serving base station and adding the target base station to an active set when a first parameter, Ec/Io, associated with the target base station is greater than a threshold parameter T_Add;
• and
• b) means for initiating a reverse link intergenerational hard handoff, wherein the hard handoff initiation means is responsive to the serving base station, and wherein the hard handoff initiation means initiates the reverse link intergenerational hard handoff as a reverse link portion of the intergenerational handoff when the serving base station transmits an intergenerational handoff direction message to the mobile station and when a second parameter, Eb/Nt, associated with the serving base station is less than or equal to a sum of a third parameter, Eb/Nt, associated with the target base station and an offset,
• wherein the reverse link intergenerational hard handoff comprises the reverse link portion, distinct from a forward link portion, of the intergenerational handoff, and includes terminating transmissions from the mobile station to the serving base station and subsequently initiating transmissions from the mobile station to the target base station.

A method of initiating 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, and wherein the serving base station and the target base station operate in accordance to different generations of CDMA systems, comprising:

• a) monitoring a first parameter Eb/Nt, reflective of a signal received from the serving base station;
• b) monitoring a second parameter Eb/Nt, reflective of a signal received from the target base station;
• c) monitoring a different third parameter Ec/Io, reflective of a signal received from the target base station;
• d) determining whether the third parameter is greater than a predetermined threshold parameter T_Add, and returning to step (a) if not, else sending a pilot strength measurement message (PSMM) to the serving base station and adding the target base station to an active set;
• e) determining whether the serving base station transmitted an intergenerational handoff direction message to the mobile station, and returning to step (a) if not, else continuing to step (f);
• f) determining whether the first parameter is less than or equal to the sum of the second parameter and an offset, and returning to step (a) if not, else initiating a reverse link handoff between the serving and target base stations.