| 摘要 |
In a wireless communications system having a centralized interworking functi on (IWF) and geographically distributed base stations, a packet-oriented frame selection/distribution (FSD) function forwards forward-link user data intended for a particular mobile un it directly to a primary base station, which determines whether to transmit the forward user data to the mobile unit using a fundamental channel or a supplemental channel. If the data is to be transmitted using a fundamental channel, when the base station is operating in soft handoff, the forward user data is transmitted from the primary base station back to a circuit-oriented FSD function for forwarding to all of the base stations currently participating in the soft handoff, so tha t all of the base stations can transmit the forward-link user data to the mobile unit at the same time. If the data is to be transmitted using a supplemental channel, then the primary base station is able to assign a supplemental channel and transmit the forward user data to the mobile unit using the supplemental channel in simplex mode, independent of whether or not the mobile unit is otherwise operating in soft handoff. In this way, forward-link data transmissions can be performed without first having to coordinate either the timing or the data rate with anyother base stations or with the FSD function. As such, the reactivation time needed to resume active forward-link data transmissions using a supplemental channel from the control hold state is less than the corresponding reactivation time under the prior art, which does require coordination of timing and data rate between all base stations in soft handoff.
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