Prose operation on non-serving carrier frequency

A network node for enabling Proximity Services (ProSe) operation for a wireless device on a non-serving carrier, the network node being configured to serve the wireless device on a cell on a serving carrier, the network node comprising:

• a communication interface circuit configured to communicate with the wireless device;
• a processor circuit operatively coupled to the communication interface circuit;
• and
• a memory operatively coupled to the processor circuit and storing program instructions for execution by the processor circuit, such that the processor circuit is configured to:
• receive a gap request from the wireless device for performing ProSe operation on a target cell of the non-serving carrier;
• upon receiving the gap request, determine whether the target cell on the non-serving carrier, on which the wireless device is to perform the ProSe operation, is known or unknown to the wireless device based on the wireless device being synchronized to the target cell on the non-serving carrier by knowing a timing of the target cell and being able to receive radio signals from the target cell;
• configure the wireless device, using the communication interface circuit:
• with a first gap configuration for a case that the target cell on the non-serving carrier is known to the wireless device, wherein the first gap configuration comprises a first gap of a first duration before a start of a ProSe operation duration, wherein the ProSe operation duration includes transmission durations that correspond to subframes expected to be used for ProSe;
• and
• with a second gap configuration for a case that the target cell on the non-serving carrier is unknown to the wireless device, wherein the second gap configuration comprises a second gap of a second duration before the start of the ProSe operation duration, and wherein the duration of the gap of the first gap configuration and the second gap configuration is lesser than a ProSe transmission period;
• adapt scheduling for the wireless device based on the first gap configuration and the second gap configuration, wherein the adapting the scheduling of the wireless device comprises not scheduling the wireless device on the cell on the serving carrier during one of:
• the duration of the gap of the first gap configuration for the case that the target cell on the non-serving carrier is known to the wireless device, and
• the duration of the gap of the second gap configuration for the case that the target cell on the non-serving carrier is unknown to the wireless device;
• and
• signal the gap configuration configured for the wireless device to one or more network nodes.

A method performed in a wireless device for performing Proximity Services (ProSe) operation on a non-serving carrier, the wireless device being served by a network node on a cell on a serving carrier, the method comprising:

• sending a gap request to a network node for performing ProSe operation on a target cell of the non-serving carrier;
• obtaining:
• a first gap configuration for a case that the target cell on the non-serving carrier is known to the wireless device, wherein the first gap configuration comprises a first gap of a first duration before the start of a Prose operation duration, wherein the ProSe operation duration includes transmission durations that correspond to subframes expected to be used for ProSe, and
• a second gap configuration for a case that the target cell on the non-serving carrier is unknown to the wireless device, wherein the second gap configuration comprises a second gap of a second duration before start of the ProSe operation duration;
• determining whether the target cell on the non-serving carrier is known or unknown to the wireless device based on the wireless device being synchronized to the target cell on the non-serving carrier by knowing a timing of the target cell and being able to receive radio signals from the target cell;
• and
• applying one of the first gap configuration and the second gap configuration for
• performing the ProSe operation on the target cell on the non-serving carrier, wherein the wireless device is not scheduled on the cell on the serving carrier during one of:
• the duration of the gap of the first gap configuration for the case that the target cell on the non-serving carrier is known to the wireless device, and
• the duration of the gap of the second gap configuration for the case that the target cell on the non-serving carrier is unknown to the wireless device, and wherein the duration of the gap of the first gap configuration and the second gap configuration is lesser than a ProSe transmission period.

A wireless device for performing Proximity Services (ProSe) operation on a non-serving carrier, the wireless device being served by a network node on a cell on a serving carrier, the wireless device comprising:

• a receiver and a transmitter configured to communicate with the network node;
• a processor circuit operatively coupled to the receiver and the transmitter;
• and
• a memory operatively coupled to the processor circuit and storing program instructions for execution by the processor circuit, such that the processor circuit is configured to:
• send a gap request to the network node for performing ProSe operation on a target cell of the non-serving carrier;
• obtain:
• a first gap configuration for a case that the target cell on the non-serving carrier is known to the wireless device, wherein the first gap configuration comprises a first gap of a first duration before the start of a Prose operation duration, wherein the ProSe operation duration includes transmission durations that correspond to subframes expected to be used for ProSe;
• and
• a second gap configuration for a case that the target cell on the non-serving carrier is unknown to the wireless device, wherein the second gap configuration comprises a second gap of a second duration before start of the ProSe operation duration;
• determine whether the target cell on the non-serving carrier is known or unknown to the wireless device based on the wireless device being synchronized to the target cell on the non-serving carrier by knowing a timing of the target cell and being able to receive radio signals from the target cell;
• and
• apply one of the first gap configuration and the second gap configuration for performing the ProSe operation on the target cell on the non-serving carrier, wherein the wireless device is not scheduled on the cell on the serving carrier during one of:
• the duration of the gap of the first gap configuration for the case that the target cell on the non-serving carrier is known to the wireless device, and
• the duration of the gap of the second gap configuration for the case that the target cell on the non-serving carrier is unknown to the wireless device,
• wherein the duration of the gap of the first gap configuration and the second gap configuration is lesser than a ProSe transmission period, wherein the processor is further configured to:
• obtain by determining whether the target cell on the non-serving carrier, on which the wireless device is to perform the ProSe operation, is known or unknown to the wireless device, and to:
• determine a duration of a gap of the first gap configuration for the case that the target cell on the non-serving carrier is known to the wireless device, and
• determine a duration of a gap of a second gap configuration for the case that the target cell on the non-serving carrier is unknown to the wireless device, and wherein the wireless device is further configured to signal the determined durations to the network node.