System and method for secure cell redirection in wireless networks

User equipment (UE), comprising:

• a wireless interface configured to connect to a first access network and a second access network;
• and
• a processing circuit configured to:
• generate a Radio Resource Control (RRC) Connection message without integrity protection including an NAS signaling message, wherein the NAS signaling message includes an initial attach indicator with a service request for a voice call;
• transmit the RRC connection message without integrity protection to the first access network prior to having an established security context with a wireless base station in the first access network;
• perform a Non-Access Stratum (NAS) authentication procedure with a mobility management entity (MME) in a core network for securing communications between the MME and the UE;
• process an RRC connection release message from the mobility management entity (MME) via the first access network, wherein the RRC connection release message includes a cell redirection command in a payload with integrity protection;
• and
• perform authentication of the cell redirection command in the payload of the RRC connection release message.

A control node in a core network, comprising:

• a network interface configured to communicate signaling messages with user equipment (UE) via a base station in a first access network;
• a processing device configured to:
• receive an initial attach request message from the UE in the first access network prior to an NAS security context with the UE, wherein the initial connection message includes a service request for a voice call;
• perform an NAS authentication procedure with the UE and generate an integrity key;
• process the service request from the UE;
• generate an NAS signaling message with integrity protection generated using the integrity key, wherein the NAS signaling message includes a cell redirection command;
• and
• wherein the NAS signalling message is included in a payload of an RRC connection message for transmission to the UE.