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Control of handoff in CDMA cellular systems

  • US 6,201,969 B1
  • Filed: 06/02/1998
  • Issued: 03/13/2001
  • Est. Priority Date: 06/02/1998
  • Status: Expired due to Term
First Claim
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1. In a wireless cellular CDMA telecommunications system, a method of obtaining a neighbor list for a base station being added to serve a call during a soft handoff, comprising the steps of:

  • storing a neighbor list and an associated time stamp for a plurality of base stations in each base station;

    in response to detecting a need for adding another base station for a soft handoff, transmitting a request message comprising a time stamp of a stored neighbor list of the base station to which the request is addressed;

    if the base station receiving the handoff request has a time stamp for its own neighbor list that is the same as the time stamp of the received request message, transmitting an acknowledgment that does not include a neighbor list;

    if the base station receiving the handoff request has a time stamp for its own neighbor list that is greater than the time stamp of the received handoff request message, transmitting in an acknowledgment message to the base station that sent the request message, a neighbor list and time stamp stored for the base station that is transmitting the acknowledgment message; and

    in response to receipt of a neighbor list and time stamp in the acknowledgment message, storing that neighbor list and time stamp as a data base entry for the base station transmitting the acknowledgment.

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