TECHNICAL FIELD

The present disclosure pertains to wireless communication technology, in particular radio access technology (RAT) and/or a radio access network (RAN), which may be a 5G network, e.g. according to 3GPP/NR (New Radio).

BACKGROUND

The physical layer of NR (the 3GPP 5G mobile radio systems) is expected to handle a vast number of different transmission scenarios by supporting multiple transmission numerologies, variable data transmission time intervals and early decoding for latency critical applications. These new scenarios impose a need for the physical layer to be even more flexible than the case when LTE was first designed. In addition to these new transmission scenarios, the physical layer of NR should be able to handle different transmission characteristics in terms of large variations in SINR, Doppler, delay spreads and channel richness.

In mobile radio systems, reference signals for coherent demodulation of physical layer control and data channels signals may be transmitted within an OFDM waveform. The reference signal (RS) is multiplexed with the physical layer channels and mapped on the OFDM time-frequency resource grid as configured by the network. In LTE downlink, the demodulation can be based on either cell-specific RS (CRS) or UE-specific RS (e.g. DM-RS), the type of which to be used depends on configured transmission mode. The mapping of CRS on the time-frequency resource grid follows from the transmit-antenna configuration together with a cell-specific frequency shift, derived during initial access, whereas the DM-RS mapping depends on the number of MIMO-layers.

The UE-specifically configured DM-RS can be pre-coded in the same way as the corresponding physical layer channels and dynamically adapt the number of MIMO-layers to the radio channel conditions. Hence, one DM-RS antenna port is used per spatial MIMO layer scheduled to the UE. An antenna port is associated to a given RS pattern of resource elements over a time and frequency region. Different antenna ports may map to different resource elements to provide orthogonality.

Each transmitted MIMO layer thus has one associated DM-RS antenna port, and, since the data transmitted in that layer is precoded with the same precoder as the associated DM-RS, it is said that the data is transmitted on the associated DM-RS antenna port. The receiver will use the associated antenna port when demodulating the data of a layer.

It may be preferable if different antenna ports are orthogonal when transmitted, as it gives better channel estimation performance at the receiver. This can be achieved by separation in time and frequency (different resource elements) or by using a combination with orthogonal cover codes (OCC) across multiple resource elements in time or frequency.

With DM-RS, LTE supports up to 8-MIMO layers in downlink by using OCC in time.

FIG. 1exemplarily illustrates the mapping of CRS and DM-RS patterns.

Like LTE, NR will be using OFDM based waveforms with reference signals and physical layer channels mapped on a time-frequency resource grid (in particular, for DL, in UL a special form of OFDM may be used, SC-FDM). Reference signals to be used in NR for demodulation of physical layer channels have not yet been specified but will primarily be based on UE-specifically configured DM-RS patterns that can support multiple transmission numerologies, variable data transmission time intervals and early decoding for latency critical applications.

FIG. 2shows DM-RS structures that have been discussed to meet requirements of early decoding or for low Doppler/low UE mobility (e.g., low relative speed). In this structure, the early transmission of DM-RS enables demodulation and decoding of data to start almost directly after receiving the second OFDM symbol in the slot.

SUMMARY

It is an object of this disclosure to provide approaches allowing improved handling of reference signaling, in particular PT-RS. The approaches in some aspects may facilitate low overhead for configuring and/or adaptive correction for phase errors.

There is disclosed a transmitting node for a Radio Access Network, the transmitting node being adapted for transmitting, based on one or more transmission parameters, of reference signaling and/or signaling including reference signaling. The reference signaling comprises phase tracking reference signaling, and the one or more transmission parameters comprise a Modulation and Coding Scheme, MCS.

Also, a method for operating a transmitting node in a Radio Access Network, the method comprises transmitting, based on one or more transmission parameters, of reference signaling and/or signaling including reference signaling. The reference signaling comprises phase tracking reference signaling, and the one or more transmission parameters comprise a Modulation and Coding Scheme, MCS.

The one or more transmission parameters may pertain to transmission by the transmitting node, e.g. according to a configuration, and/or to a specific channel like a physical channel, e.g. a data channel like a Physical Uplink Shared CHannel like PUSCH, or a Physical Downlink Shared Channel like PDSCH, or a control channel like a physical uplink or downlink control channel like PUCCH or PDCCH.

Accordingly, no additional signaling is needed to indicate whether and/or how the reference signaling is to be transmitted.

In general, the one or more transmission parameters may be configured or indicated with a control message, in particular a DCI message. Transmission of reference signaling like phase tracking reference signaling may be based on a reference signaling configuration. The configuration may be indicated by the control message, e.g. a MCS indication therein. A MCS indication may generally comprise an indicator or index or pointer or value or bit field indicating a MCS type and/or a MCS to be used or used for transmission. A transmission parameter may be configured or scheduled, and may be considered a scheduling parameter.

The transmitting node may be a radio node, in particular a terminal or a network node. A receiving node receiving the reference signaling or associated transmission may be complementary thereto a network node or a terminal.

In some cases, transmitting may be in downlink, and/or may be terminal-specific and/or beam-formed.

Phase tracking reference signaling may be on one or more subcarriers, e.g. associated to a carrier or carrier frequency. The one or more subcarriers may be carriers for which also demodulation reference signaling (DM-RS) is scheduled, e.g. for the same slot or subframe, and/or leading in time compared to the phase tracking reference signaling.

There is also disclosed a program product comprising code executable by control circuitry, the code causing the control circuitry to carry out and/or control a method as described herein.

Moreover, a carrier medium arrangement carrying and/or storing a program product as disclosed herein is described.

Alternative or additional approaches are also discussed in the following.

