US 7,889,867 B2 · Method for relocating SRNS in a mobile communication system

Abstract

A system and method for performing SRNS relocation in a communications system transmits radio resource information including a ciphering parameter from a source RNC to a target RNC, modifies the ciphering parameter to coincide with a deciphering parameter which a user terminal uses when out-of-sequence data is received, ciphers a data unit based on the modified ciphering parameter, and transmits the ciphered data unit from the target RNC to the user terminal. The method may be modified to operate in UM mode or AM mode and to transmit data over one of several radio bearers. In accordance with another embodiment, the system and method transmits radio resource information from a source RNC to a target RNC and then transmits a data unit from the target RNC to a user terminal. In this case, the data unit including a transmission sequence number which consecutively follows a transmission sequence number of a data unit last transmitted from the source RNC to the user terminal. In accordance with another embodiment, the system and method resets ciphering and state variables in a target RNC and then transmits a message instructing a user terminal to reset a deciphering and state variables to the same or similar values. All the embodiments are advantageous because they ensure successful communications will take place between the target RNC and user terminal after a serving radio network sub-system relocation procedure is performed.

Claims13

Dependent claims

A radio network controller for relocating serving radio network sub-systems, the radio network controller comprising:

a receiver adapted to receive ciphering information and a state variable value from a source radio network controller, wherein the ciphering information comprises at least a downlink hyper frame number of a first signaling radio bearer or an uplink hyper frame number of the first signaling radio bearer;
and
a processor adapted to perform steps of:
establishing an unacknowledged mode radio link control entity for the first signaling radio bearer;
ciphering a first data in the unacknowledged mode radio link control entity using at least the ciphering information or the state variable value received from the source radio network controller;
transmitting the ciphered first data to a mobile terminal;
establishing an acknowledged mode radio link control entity for a second signaling radio bearer;
determining a greater value between a downlink hyper frame number of the second signaling radio bearer and an uplink hyper frame number of the second signaling radio bearer;
incrementing the determined greater value by one;
and
receiving a second data including a start value.

8 more elements

Dependencies are inferred from the claim text.

Method for relocating SRNS in a mobile communication system

Life of this patent

Method for relocating SRNS in a mobile communication system

Life of this patent

Abstract

Claims13