Phase tracking reference signal configuration for rate-splitting multiple input multiple output communications

An apparatus for wireless communication at a network node, comprising:

• one or more processors;
• memory coupled with the one or more processors;
• and
• instructions stored in the memory and executable by the one or more processors to cause the apparatus to:
• transmit, to a plurality of UEs comprising at least a first UE and a second UE, a first control message identifying that multi-user multiple input multiple output signals from the network node comprise one or more private messages for the first UE and one or more common messages for the first UE and at least the second UE;
• transmit a second control message that identifies a first phase tracking reference signal port for the one or more private messages and a second phase tracking reference signal port for the one or more common messages, wherein the second control message indicates that the first phase tracking reference signal port is associated with a lowest demodulation reference signal port index of a first plurality of demodulation reference signal port indices corresponding to the one or more private messages;
• and
• transmit the one or more private messages using the first phase tracking reference signal port that is based at least in part on the lowest demodulation reference signal port index and the one or more common messages using the second phase tracking reference signal port.

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

• receiving, from a network node, a first control message identifying that multi-user multiple input multiple output signals from the network node comprise one or more private messages for the UE and one or more common messages for the UE and at least one second UE;
• receiving a second control message that identifies a first phase tracking reference signal port for the one or more private messages and a second phase tracking reference signal port for the one or more common messages, wherein the second control message indicates that the first phase tracking reference signal port is associated with a lowest demodulation reference signal port index of a first plurality of demodulation reference signal port indices corresponding to the one or more private messages;
• and
• receiving the one or more private messages using the first phase tracking reference signal port that is identified based at least in part on the lowest demodulation reference signal port index and the one or more common messages using the second phase tracking reference signal port.

A method for wireless communication at a network node, comprising:

• transmitting, to a plurality of UEs comprising at least a first UE and a second UE, a first control message identifying that multi-user multiple input multiple output signals from the network node comprise one or more private messages for the first UE and one or more common messages for the first UE and at least the second UE;
• transmitting a second control message that identifies a first phase tracking reference signal port for the one or more private messages and a second phase tracking reference signal port for the one or more common messages, wherein the second control message indicates that the first phase tracking reference signal port is associated with a lowest demodulation reference signal port index of a first plurality of demodulation reference signal port indices corresponding to the one or more private messages;
• and
• transmitting the one or more private messages using the first phase tracking reference signal port that is identified based at least in part on the lowest demodulation reference signal port index and the one or more common messages using the second phase tracking reference signal port.