SPATIAL ALIGNMENT FOR D2D INTERFERENCE MITIGATION
First Claim
1. A method for operating an evolved Node B (eNB) in an LTE (Long Term Evolution) network, comprising:
- generating a spatial decoder for receiving uplink transmissions from a first user equipment (UE) based upon transmissions from the first UE;
receiving an uplink transmission from a second UE requesting device-to-device (D2D) time-frequency resources for transmitting to another UE over a D2D link; and
,employing the generated spatial decoder to compute a measure of the interference that would occur between uplink transmissions of the first UE and D2D transmissions of the second UE if common time-frequency resources were to be used.
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Abstract
Described are techniques for managing the interference produced by D2D (device-to-device) transmissions that may be used in conjunction with transmit power control but operate independently. In one technique, interference between D2D transmissions and cellular uplink transmissions using common resources as received at a base station is managed by opportunistic interference alignment and clustering of D2D devices. In another technique, interference between different D2D devices using the same resources is mitigated by base-station aided space-time interference alignment.
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Citations
25 Claims
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1. A method for operating an evolved Node B (eNB) in an LTE (Long Term Evolution) network, comprising:
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generating a spatial decoder for receiving uplink transmissions from a first user equipment (UE) based upon transmissions from the first UE; receiving an uplink transmission from a second UE requesting device-to-device (D2D) time-frequency resources for transmitting to another UE over a D2D link; and
,employing the generated spatial decoder to compute a measure of the interference that would occur between uplink transmissions of the first UE and D2D transmissions of the second UE if common time-frequency resources were to be used. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A user equipment (UE) device, comprising:
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a radio-frequency transceiver to provide an air interface for LTE (Long Term Evolution) and D2D (device-to-device) communications; and processing circuitry connected to the radio-frequency transceiver to; receive allocations of D2D time-frequency resources for transmitting in a D2D communications mode from an evolved Node B (eNB); receive a codebook index that specifies a spatial decoder from the eNB, wherein the codebook index corresponds to a spatial decoder generated by the eNB for receiving signals from a cellular UE; compare a spatial channel direction derived from the specified spatial decoder and a channel direction between the UE and the eNB to derive a measure of the interference that would occur at the eNB between D2D transmissions by the UE and uplink transmissions by the cellular UE. - View Dependent Claims (12, 13, 14, 15, 16)
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17. A method for operating an evolved Node B (eNB) serving a cell in an LTE (Long Term Evolution) network, comprising:
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receiving transmissions from D2D (device-to-device) transmitters belonging to a first set of D2D transmitter/receiver pairs using common time-frequency resources in a first time slot and employing multiple antennas to spatially decode symbols transmitted by each D2D transmitter; receiving transmissions from D2D transmitters belonging to a second set of D2D transmitter/receiver pairs using common time-frequency resources in a second time slot and employing multiple antennas to spatially decode symbols transmitted by each D2D transmitter; and
,transmitting to D2D receivers belonging to the first and second sets a weighted sum of the decoded symbols in a third time slot, wherein the weighting of the weighted sum is such that that the D2D receivers of the first set are able to extract the symbols transmitted during the first time slot and such that that the D2D receivers of the second set are able to extract the symbols transmitted during the second time slot. - View Dependent Claims (18, 19, 20, 21)
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22. A user equipment (UE) device, comprising:
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a radio transceiver to provide an air interface for communicating with an evolved node B (eNB) and for device-to-device (D2D) communications; and processing circuitry to; receive a transmitted symbol from a first D2D transmitter during a first time slot along with interfering transmissions from a second D2D transmitter using common time-frequency resources; receive interfering transmissions from third and fourth D2D transmitters in a second time slot; receive transmissions in a third time slot from the eNB that are a weighted sum of symbols transmitted by the first, second, third, and fourth D2D transmitters during the first and second time slots; use the transmissions received during the first, second, and third time slots to extract the symbol transmitted by the first D2D transmitter in the first time slot. - View Dependent Claims (23, 24, 25)
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Specification