Enabling coexistence between FDD and TDD wireless networks
View Patent ↗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.
1. A method of detecting and mitigating interference between a wireless frequency division duplex (FDD) communications device in communication with an FDD base station and a wireless time division duplex (TDD) communications device, wherein an FDD uplink frequency band includes first and second frequencies, such that the first frequency is adjacent to a TDD transmission frequency band, the method comprising:
determining, using a processor, whether 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
responsive to a determination that the monitored value of the operational parameter of the FDD device is within the fixed range of the maximum value of the operational parameter,
configuring the FDD base station such that the FDD base station receives data packets from the FDD device on a reduced-interference frequency selected from within the FDD uplink frequency band such that the reduced-interference frequency is either closer to the second frequency than the first frequency, or the reduced-interference frequency is at a center of the FDD uplink frequency band.
2. The method of claim 1 , wherein a TDD base station in communication with the TDD base station comprises a WiMAX base station and the TDD device comprises a WiMAX device, and the FDD base station comprises an LTE base station and the FDD device comprises an LTE device.
3. The method of claim 1 , wherein the operational parameter comprises a transmit power level at which the FDD device is transmitting FDD frames to the FDD base station.
4. An apparatus capable of operating in a wireless network, and detecting and mitigating interference between wireless devices, the apparatus comprising:
a transceiver configured to exchange FDD data packets with a wireless frequency division duplex (FDD) communications device, such that an FDD uplink frequency band includes first and second frequencies, such that the first frequency is adjacent to a TDD transmission frequency band of a TDD network;
a parameter-monitoring module to determine 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;
a memory device configured to store the monitored value of the operational parameter of the FDD device, and frame information including a TDD downlink time interval associated with TDD frames; and
a configuration-adjustment module that, responsive to a determination that the monitored value is within the fixed range of the maximum value of the operational parameter, configures the transceiver such that:
the transceiver receives FDD data packets from the FDD device on a reduced-interference frequency selected from within the FDD uplink frequency band such that the reduced-interference frequency is either closer to the second frequency than the first frequency, or the reduced-interference frequency is at a center of the FDD uplink frequency band.
5. The apparatus of claim 4 , wherein the operational parameter comprises a transmit power level at which the FDD device is transmitting FDD frames to the transceiver.
6. The method of claim 1 , further comprising, responsive to the determination that the monitored value of the operational parameter of the FDD device is within the fixed range of the maximum value of the operational parameter, configuring the FDD base station such that the FDD device does not transmit data packets to the FDD base station during a TDD downlink time interval.
7. The method of claim 6 , further comprising providing a frame-structure parameter to the FDD base station, wherein the frame-structure parameter indicates a frame configuration of TDD frames including the TDD downlink time interval.
8. The apparatus of claim 4 , wherein the configuration-adjustment module, responsive to the determination that the monitored value is within the fixed range of the maximum value of the operational parameter, further configures the transceiver such that the FDD device does not transmit data packets to the transceiver during the TDD downlink time interval.