Radio network node, a wireless device and methods therein for re-establishing a radio connection

A method performed by a wireless device for re-establishing a radio connection in a wireless communications network comprising a first Radio Access Technology, RAT, and a second RAT being different from the first RAT, wherein the wireless device is operating in a first cell served by a first radio network node operating in the first RAT, and wherein the method comprises:

• when a connection failure with the first cell served by the first radio network node is detected:
• performing a cell selection;
• selecting a second cell served by a second radio network node operating in the second RAT, wherein the second cell is known by the wireless device to be a candidate for re-establishment;
• determining a first set of parameters associated with the first cell, wherein the first set of parameters comprises at least one parameter identifying the wireless device or the first cell;
• receiving a second set of parameters associated with the second cell, wherein the second set of parameters comprises at least one parameter identifying the wireless device or the second cell;
• determining an updated version of one or more parameters of the first set of parameters or an updated version of one or more parameters of the second set of parameters;
• determining a security token based on at least one out of:
• the first set of parameters and the updated version of the one or more parameters of the first set of parameters, and based on at least one out of:
• the second set of parameters and the updated version of the one or more parameters of the second set of parameters;
• and
• transmitting to the second cell, a re-establishment request message comprising the determined security token.