Method and radio access point for handling communication between wireless devices

1. A method performed by a radio access point in a wireless network for handling a two-way communication between a first wireless device and a second wireless device, wherein the first and second wireless devices are both served by the radio access point and wherein a set of candidate transmission modes are available for use in the two-way communication, the method comprising:

identifying, among a plurality of radio resources, a set of radio resources that are unused,

obtaining a mode-specific quality metric related to a predicted Signal to Interference and Noise Ratio SINR for each transmission mode in the set of candidate transmission modes on the identified set of radio resources,

selecting a transmission mode from the set of candidate transmission modes based on the mode-specific quality metrics obtained for the set of candidate transmission modes, and

applying the selected transmission mode for the two-way communication between the first and second wireless devices.

2. The method according to claim 1 , wherein the set of candidate transmission modes comprises at least two of:

a cellular mode where the first wireless device and the second wireless device communicate via the radio access point over respective cellular radio links,

a Device-to-Device D2D mode where the first wireless device and the second wireless device communicate directly over a D2D radio link between the first and second wireless devices,

a network coding mode where the first wireless device and the second wireless device communicate via the radio access point over the respective cellular radio links and the radio access point performs network coding of first data transmitted from the first wireless device and of second data transmitted from the second wireless device,

a network coding with combining mode where the first wireless device and the second wireless device communicate over the D2D radio link assisted by network coding by the radio access point of the first data transmitted from the first wireless device and of the second data transmitted from the second wireless device, and

a physical layer network coding mode where the radio access point amplifies and transmits a superposition of signals simultaneously transmitted by the first wireless device and the second wireless device.

3. The method according to claim 1 , wherein the predicted SINR of each transmission mode is an end-to-end SINR valid for a total communication path between the first wireless device and the second wireless device.

4. The method according to claim 1 , wherein the radio access point selects the transmission mode according to at least one of:

select the transmission mode that has the highest predicted end-to-end SINR,

select the transmission mode that has the highest predicted spectral efficiency, and

select the transmission mode that has the lowest predicted Bit Error Rate BERI.

5. The method according to claim 1 , wherein applying the selected transmission mode comprises signalling the selected transmission mode to the first wireless device and to the second wireless device.

6. The method according to claim 1 , wherein the radio access point obtains the mode-specific quality metric based on a Device-to-Device D2D radio link quality report received from at least one of the first wireless device and the second wireless device.

7. The method according to claim 1 , wherein the radio access point obtains the mode-specific quality metrics, for the set of candidate transmission modes, based on measurements of respective cellular radio links between the radio access point and the first and second wireless devices.

8. A radio access point operable in a wireless network and arranged to handle a two-way communication between a first wireless device and a second wireless device, wherein the first and second wireless devices are both served by the radio access point, and wherein a set of candidate transmission modes are available for use in the two-way communication, the radio access point comprising a processor configured to:

identify, among a plurality of radio resources, a set of radio resources that are unused, obtain a mode-specific quality metric related to a predicted Signal to Interference and Noise Ratio SINR for each transmission mode in the set of candidate transmission modes on the identified set of radio resources,

select a transmission mode, from the set of candidate transmission modes, based on the mode-specific quality metrics obtained for the set of candidate transmission modes, and

apply the selected transmission mode for the two-way communication between the first and second wireless devices.

9. The radio access point according to claim 8 , wherein the set of candidate transmission modes comprises at least two of:

a cellular mode where the first wireless device and the second wireless device communicate via the radio access point over respective cellular radio links,

a Device-to-Device D2D mode where the first wireless device and the second wireless device communicate directly over a D2D radio link between the first and second wireless devices,

a network coding mode where the first wireless device and the second wireless device communicate via the radio access point over the respective cellular radio links and the radio access point performs network coding of first data transmitted from the first wireless device and of second data transmitted from the second wireless device,

a network coding with combining mode where the first wireless device and the second wireless device communicate over the D2D radio link assisted by network coding by the radio access point of the first data transmitted from the first wireless device and of the second data transmitted from the second wireless device, and

a physical layer network coding mode where the radio access point amplifies and transmits a superposition of signals simultaneously transmitted by the first wireless device and the second wireless device.

10. The radio access point according to claim 8 , wherein the predicted SINR of each transmission mode is an end-to-end SINR valid for a total communication path between the first wireless device and the second wireless device.

11. The radio access point according to claim 8 , wherein the processor is configured to select the transmission mode according to at least one of:

select the transmission mode that has the highest predicted end-to-end SINR,

select the transmission mode that has the highest predicted spectral efficiency, and

select the transmission mode that has the lowest predicted Bit Error Rate BER.

12. The radio access point according to claim 8 , wherein the processor is configured to apply the selected transmission mode by signalling the selected transmission mode to the first wireless device and to the second wireless device.

13. The radio access point according to claim 8 , wherein the processor is configured to obtain the mode-specific quality metric based on a Device-to-Device D2D radio link quality report received from at least one of the first wireless device and the second wireless device.

14. The radio access point according to claim 8 , wherein the processor is configured to obtain the mode-specific quality metrics, for the set of candidate transmission modes, based on measurements of respective cellular radio links between the radio access point and the first and second wireless devices.