Dynamic band selection for interference minimization in direct device to device communications

#The present disclosure relates to direct device to device communications in a cellular communication network and more particularly relates to minimizing interference resulting from direct device to device communications in a cellular communication network.

#Network-assisted direct device to device (D2D) communication is expected to be a key feature supported by next generation cellular communication networks. FIG. 1 illustrates a cellular communication network 10 that enables direct D2D communications. As illustrated, the cellular communication network 10 includes a base station (BS) 12 that serves a corresponding cell 14 of the cellular communication network 10. While only one base station 12 is illustrated, the cellular communication network 10 includes numerous base stations 12 serving corresponding cells 14. In this example, wireless devices (WDs) 16, 18, and 20 are located within the cell 14. The wireless devices 16 and 18 are in proximity to one another. As such, when the wireless devices 16 and 18 desire to establish a bearer link, rather than establishing the bearer link through the base station 12, the cellular communication network 10 assists the wireless devices 16 and 18 to establish a direct D2D communication link (i.e., a direct D2D bearer link) between one another. More specifically, through signaling with the base station 12 or some other mechanism, the wireless devices 16 and 18 discover one another using a D2D device discovery process and then establish a D2D communication link directly between one another rather than through the base station 12.

#Direct D2D communication is possible regardless of whether the cellular communication network 10 is Frequency Division Duplex (FDD) (i.e., uses different uplink and downlink frequency bands) or Time Division Duplex (TDD) (i.e., using the same frequency band but different time slots for uplink and downlink). However, it is commonly accepted that a direct D2D communication link, such as that established between the wireless devices 16 and 18, is preferably a TDD communication link where transmissions by one wireless device use the same resources as reception by the other wireless device. These “resources” are physical frequency and/or time resources depending on the particular implementation of the cellular communication network 10. TDD (i.e., half duplex operation) is preferred because operating a transmitter and receiver in the same frequency band in a half duplex fashion is easier to implement than a full duplex FDD implementation.

#The accompanying drawing figures incorporated in and forming a part of this specification illustrate several aspects of the disclosure, and together with the description serve to explain the principles of the disclosure.

#FIG. 1 illustrates a direct device-to-device (D2D) communication link in a cellular communication network;

#FIG. 2 illustrates a direct D2D communication link in a cellular communication network, where the direct D2D communication link utilizes a downlink (DL) resource of the cellular communication network and causes strong interference in a downlink to a wireless device in a neighboring cell that uses the same DL resource;

#The embodiments set forth below represent the necessary information to enable those skilled in the art to practice the embodiments and illustrate the best mode of practicing the embodiments. Upon reading the following description in light of the accompanying drawing figures, those skilled in the art will understand the concepts of the disclosure and will recognize applications of these concepts not particularly addressed herein. It should be understood that these concepts and applications fall within the scope of the disclosure and the accompanying claims.

#Systems and methods are disclosed for selecting resources for direct device to device (D2D) communications in a cellular communication network. Preferably, resources for the direct D2D communications are selected to minimize, or at least substantially reduce, interference that results from the direct D2D communications in the cellular communication network. In general, either an uplink (UL) resource or a downlink (DL) resource of the cellular communication network is selected for a direct D2D communication link between a first wireless device and a second wireless device in order to minimize, or at least substantially reduce, interference caused to a third wireless device that uses the same UL and DL resources in the same and/or a neighboring cell of the cellular communication network.

#FIG. 4 illustrates a cellular communication network 28 where a UL or DL resource of the cellular communication network 28 is selected for a direct D2D communication link in such a manner as to minimize, or at least substantially reduce, inter-cell interference according to one embodiment of the present disclosure. As illustrated in FIG. 4, the cellular communication network 28 includes a base station 30 (BS1) that serves a corresponding cell 32 of the cellular communication network 28. In addition, the cellular communication network 28 includes a base station 34 (BS2) that serves a corresponding cell 36 of the cellular communication network 28. The cells 32 and 36 neighbor one another in the cellular communication network 28. As such, the cell 36 is also referred to herein as a neighboring cell 36 of the cell 32, and the base station 34 is also referred to herein as a neighboring base station 34 of the base station 30. In one particular non-limiting embodiment, the base stations 30 and 34 are eNodeBs (eNBs) in a Long Term Evolution (LTE) cellular communication network. However, the base stations 30 and 34 are not limited thereto.