A method performed by a User Equipment, UE , the method comprising: identifying a policy indicating a first dedicated bearer associated with a first guaranteed Quality of Service, QoS, level is network-initiated, the first dedicated bearer being used to establish voice services through a core network and an Internet Protocol, IP, Media Subsystem, IMS, network; initiating a call by transmitting a first Session Initiation Protocol, SIP, message to the core network, the first SIP message requesting the voice services from the core network and the IMS network; receiving a second SIP message from the core network; in response to the second SIP message being received as a dedicated bearer establishment request message including a request to establish the dedicated bearer, triggering a timer associated with a wait time to start; determining, as an expired timer, the timer at expiration of the wait time, without a confirmation of establishment of the dedicated bearer associated with delivery of the voice services through the core network and the IMS network having been received; andin response to the expired timer being associated with a start time at which the dedicated bearer establishment request message has been received, and an expiration time at which establishment of the first dedicated bearer has not been confirmed, initiating a fallback option for the call, wherein initiating the fallback option comprises transmitting, to the core network, a request for a second dedicated bearer associated with a second guaranteed QoS level, the second guaranteed QoS level being lower than the first guaranteed QoS level; receiving a confirmation of the second dedicated bearer from the core network; and receiving the voice services from the core network via the second dedicated bearer. identifying a policy indicating a first dedicated bearer associated with a first guaranteed Quality of Service, QoS, level is network-initiated, the first dedicated bearer being used to establish voice services through a core network and an Internet Protocol, IP, Media Subsystem, IMS, network; initiating a call by transmitting a first Session Initiation Protocol, SIP, message to the core network, the first SIP message requesting the voice services from the core network and the IMS network; receiving a second SIP message from the core network; in response to the second SIP message being received as a dedicated bearer establishment request message including a request to establish the dedicated bearer, triggering a timer associated with a wait time to start; determining, as an expired timer, the timer at expiration of the wait time, without a confirmation of establishment of the dedicated bearer associated with delivery of the voice services through the core network and the IMS network having been received; andin response to the expired timer being associated with a start time at which the dedicated bearer establishment request message has been received, and an expiration time at which establishment of the first dedicated bearer has not been confirmed, initiating a fallback option for the call, wherein initiating the fallback option comprises transmitting, to the core network, a request for a second dedicated bearer associated with a second guaranteed QoS level, the second guaranteed QoS level being lower than the first guaranteed QoS level; receiving a confirmation of the second dedicated bearer from the core network; and receiving the voice services from the core network via the second dedicated bearer. <EOS>