Patent ID: 6980805

Claim:
A handoff control method of a CDMA system, in the handoff method of the CDMA mobile communication system one or a plurality of tiers of wireless frequencies are assigned on an individual wireless zone basis, wherein locational information of a mobile device is obtained, and when said mobile device is judged to be moving to cross a frequency-tier boundary where different frequency tiers are assigned to a cell conducting a communication and an adjacent cell, an inter-frequency handoff is performed to a tier of a common frequency prepared commonly in both said cell conducting the communication and said adjacent cell, wherein said mobile device is judged to be moving to cross the frequency-tier boundary by predicting a moving direction of said mobile device wherein the moving direction of said mobile device is conjectured by combining the locational information of said mobile device with cartogranhic information of said cell conducting the communication. and wherein a subsequent soft handoff is performed following the inter-frequency handoff.