초록 ▼

A method for performing a hard handoff of a call from a first cell site of a CDMA cellular network to a target cell site of a second cellular network, such as an AMPS network or a second CDMA network. As a mobile unit operating in the first CDMA network moves toward the second cellular network, the

A method for performing a hard handoff of a call from a first cell site of a CDMA cellular network to a target cell site of a second cellular network, such as an AMPS network or a second CDMA network. As a mobile unit operating in the first CDMA network moves toward the second cellular network, the first cell site uses two separate RTD thresholds for comparison with a measured RTD distance between the mobile unit and the first cell site. Handoff is initiated when the RTD distance exceeds the first RTD threshold and is completed when the RTD distance exceeds the second RTD threshold. If the first cell site is not co-located with a cell site of the second network, the first cell site utilizes receivers placed in the target cell site for handoff. If the first cell site is co-located with a second cell site of the second network, the second cell site of the second network is always the target cell site.

대표청구항 ▼

[ What is claimed is:] [1.] In a CDMA cellular network overlaid on an AMPS cellular network, a method for performing a handoff of a call from a mobile unit in a CDMA cell site of the CDMA cellular network wherein the CDMA cell site is co-located with an AMPS cell site of the AMPS cellular network, t

[ What is claimed is:] [1.] In a CDMA cellular network overlaid on an AMPS cellular network, a method for performing a handoff of a call from a mobile unit in a CDMA cell site of the CDMA cellular network wherein the CDMA cell site is co-located with an AMPS cell site of the AMPS cellular network, the method comprising the steps of:measuring a round trip delay ("RLTD") value representing a distance from the mobile unit to the CDMA cell site;comparing the RTD value with a first predetermined value;if the RTD value exceeds the first predetermined value, determining whether any other CDMA cell site is available for handoff;comparing the RTD value with a second predetermined value;if the RTD value exceeds the second predetermined value, handing off the call to a second CDMA cell site if one is available; andif no other CDMA cell site is available for handoff, handing off the call to the AMPS cell site.