Channel for eavesdropping-mitigation and secret key generation

A method for wireless communications at a device, comprising:

• receiving, from a user equipment (UE), a sounding reference signal;
• estimating a channel between the UE and the device based at least in part on the sounding reference signal and using a set of antennas of a plurality of antennas configured at the device;
• selecting the set of antennas in order to transmit a downlink reference signal to the UE, selection of the set of antennas based at least in part on the set of antennas being used for reception of the sounding reference signal and on the device using the sounding reference signal as part of a security key generation procedure for communications between the UE and the device;
• transmitting the downlink reference signal to the UE using the set of antennas, the downlink reference signal being generated based at least in part on the estimated channel to produce a target value that is to be used, by the UE, to derive a security key to be used to secure the communications between the UE and the device;
• and
• communicating with the UE via the communications between the UE and the device and secured using the security key.

A user equipment (UE) for wireless communication, comprising:

• a processor;
• memory coupled with the processor;
• and
• instructions stored in the memory and executable by the processor to cause the UE to:
• transmit, to a device, a sounding reference signal using a first antenna of a plurality of antennas configured at the UE;
• select the first antenna in order to receive a downlink reference signal from the device, selection of the first antenna based at least in part on the first antenna being used for transmission of the sounding reference signal and on the UE using the downlink reference signal as part of a security key generation procedure for communications between the UE and the device;
• receive the downlink reference signal from the device using the first antenna;
• deriving, via the security key generation procedure and used a value associated with the downlink reference signal, a security key to be used to secure the communications between the UE and the device;
• and
• communicate with the device via the communications between the UE and the device and secured using the security key.

A device for wireless communications, comprising:

• a processor;
• memory coupled with the processor;
• and
• instructions stored in the memory and executable by the processor to cause the device to:
• receive, from a user equipment (UE), a sounding reference signal;
• estimate a channel between the UE and the device based at least in part on the sounding reference signal and using a set of antennas of a plurality of antennas configured at the device;
• select the set of antennas in order to transmit a downlink reference signal to the UE, selection of the set of antennas based at least in part on the set of antennas being used for reception of the sounding reference signal and on the device using the sounding reference signal as part of a security key generation procedure for communications between the UE and the device;
• transmit the downlink reference signal to the UE using the set of antennas, the downlink reference signal being generated based at least in part on the estimated channel to produce a target value that is to be used, by the UE, to derive a security key to be used to secure the communications between the UE and the device;
• and
• communicate with the UE via the communications between the UE and the device and secured using the security key.