A serving MSC in a wireless communication network, such as an IS-2000 network,
uses standard signaling messages in an unconventional manner to allow it to take
on the role of an anchor MSC under certain inter-MSC handoff conditions. When a
mobile station engaged in an active packet data call is handed off from an anchor
MSC to the serving MSC, the serving MSC sends an indication to the anchor MSC that
the data call has been released even though the call is still active. The serving
MSC then causes the HLR location information for the mobile station to be updated
to identify the serving MSC as the new anchor MSC. Thus, the serving MSC becomes
the anchor MSC under conditions where it otherwise would not, which avoids routing
subsequent voice calls through the previous anchor MSC. The above approach also
includes variations that accommodate concurrent voice and data handoff scenarios.
