US Patent 8681660 Enabling coexistence between FDD and TDD wireless networks

Systems and methods for detecting and mitigating interference between from a wireless time division duplex (TDD) communications device and a wireless frequency division duplex (FDD) communications device includes processing quality-indicator reports received from the FDD device to determine if the FDD device has experienced interference from the TDD device. Such interference may be mitigated by adjusting a downlink configuration of the FDD base station in communication with the FDD device. To detect and mitigate interference from an FDD device to a TDD device, it is determined if a monitored value of an operational parameter of the FDD device is within a fixed range of a maximum value of the operational parameter, and if so, a specific time interval or frequency of the FDD device is assigned for communication purposes. Similar interference detection and mitigation techniques may also be used for interference scenarios between two TDD systems including TDD devices.