Distributed soft handoff among IP-based base stations
AssigneesTelcordia Technologies, Inc., Toshiba America Research, Inc.
InventorsPrathima Agrawal, Jyh-Cheng Chen, Tao Zhang
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Abstract
A technique for assigning an address (“shadow address”) to a mobile station that is compatible with the layer-2 address on the wireline network which serves the mobile station. The shadow address is then used as a wireline identifier for the destination address for frames ultimately destined for the mobile station. The shadow address is stored in a watch list for serving base stations, and any base station receiving a frame with a shadow address in its watch list process the frame to forward it the to mobile station. In this way, the shadow address facilitates carrying out soft handoff and smooth handoff.
Claims10
A method for synchronizing corresponding streams of packets sent to a mobile station from two different base stations, each of the packets having a corresponding Sequence number, the method comprising
- generating a stream of link layer frames by each of the base stations wherein each of the frames is of the same length,
- in each of the base stations filling in the frames with the packets starting with the same one of the packets,
- transmitting fully filled-in frames from each of the base stations to the mobile station,
- detecting two stream of frames at the mobile station wherein one of the streams is transmitted by the first of the base stations and another of the streams is transmitted by the second of the base stations,
- determining the packet sequence number of reach of the packets in each of the streams, and
- initiating a resynchronization procedure whenever packets in one or both of the steams do not have packet sequence numbers that are consecutive.
A method for transmitting data from a base station, said method comprising the steps of:
- generating layer-2 frames of the same length;
- filling each of said generated frames with data blocks received from a layer above layer-2;
- transmitting only said fully filled frames, unless
- a time expires, or
- instructions are received from the layer above layer-2 to transmit the frame currently being filled;
- receiving at the base station a first block, k, and a second block, m,
- losing data content synchronization between blocks k and m;
- and
- based on said loss of data content synchronization sending a request from the base station to at least one other base station to initiate resynchronization of data transmission beginning from a third data block, q, where q>m.
Dependencies are inferred from the claim text.