摘要 |
Base station controlled vertical handoff is disclosed. When a hybrid access terminal is operating under a first air interface protocol (e.g., IS-2000), in a mode (e.g., active) in which the terminal does not search for the presence of wireless service under a second air interface protocol (e.g., IS-856), the terminal sends a request to a base station seeking to hand off to a wireless coverage area under the protocol. The base station then determines (e.g., by reference to the PN offset specified in the request) that the target coverage area additionally provides service under the second protocol. Responsively, the base station causes the terminal to transition to a second mode (e.g., dormant) in which the terminal does search for the presence of service under the second protocol. The terminal may thereby discover the presence of service under the second protocol and may hand off to operate under the second protocol.
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