Telefonaktiebolaget Lm Ericsson (publ)

Ingemar Backlund

Gunnar Mildh

John Walter Diachina

Lars Tedenvall

Ann-Christine Eriksson

Sandra Collins

A mobile station (MS) and method for base station handover from a source cell of a source base station to a target cell of a target base station in a packet-switched cellular radio network. While the MS is still in the source cell, the MS receives from the network, a handover command message and information regarding a next expected uplink packet for a packet flow subject to lossless packet-switched handover. Upon arrival of the MS in the target cell, the MS transmits an uplink sequence number status message to the target base station providing a downlink sequence number status for the packet flow, and starts uplink data transmission to the target base station beginning with the next expected uplink packet.

Method and system for base station change of packet switched communications in a mobile communications system

The present invention relates to change of base stations transferring packet switched communications between a mobile station and a support node. The base station change is of lossless type allowing lossless base station change of packet switched communications in unacknowledged mode between the mobile station and the support node.

The present invention relates to a method and apparatus for improving the procedures for error detection and recovery in data communication systems and thereby facilitating a better use of data transmission resources. According to the invention, different protocols capable of re-transmission of data are made to communicate with each other in order to avoid that several protocols simultaneously re-transmit the same data towards the same interface. The transmitting entity of a higher layer protocol will, according to the invention, await the result of the transmission of a certain protocol data unit by a lower layer protocol before making the decision of whether or not the transmitting entity of the higher layer protocol should re-transmit the certain protocol data unit.

Method and apparatus relating to retransmission of data between different protocol layers

A method ensures that data is not lost during an inter-Routing Area or inter-Network Service Entity cell change in a GPRS network. When a mobile station passes from one cell into another, a command is sent from the SGSN to the BSS serving the first cell, causing that BSS to discard any data awaiting transmission to the mobile station. A reply is sent from the BSS to the SGSN, and, in response thereto, the SGSN transmits data to the BSS serving the new cell, in order to ensure that all of the data intended for the mobile station is transmitted thereto.

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Sollentuna, Sweden

Ingemar Backlund