WO2020030254A1

WO2020030254A1 - Joint channel estimation

Info

Publication number: WO2020030254A1
Application number: PCT/EP2018/071400
Authority: WO
Inventors: Xiaohui Liu; Neng Wang
Original assignee: Huawei Technologies Co., Ltd.
Priority date: 2018-08-07
Filing date: 2018-08-07
Publication date: 2020-02-13

Abstract

In order to demodulate data received via a physical downlink shared channel, PDSCH, a client device may need to estimate the channel of the PDSCH. The channel estimate quantifies how physical phenomena, such as the Doppler shift, affect the data during wireless transmission. It is an object to provide a procedure for improving channel estimation in wireless radio communication. A client device may perform joint channel estimation for PDSCH data based on a PDSCH reference signal, RS, and the at least one further signal being: physical downlink control channel, PDCCH, data, a PDCCH RS, or PDSCH data. The client device may use the channel estimate to decode PDSCH data. A client device, a network access device, methods, and a computer program are described.

Description

JOINT CHANNEL ESTIMATION

TECHNICAL FIELD

The disclosure relates to a field of wireless radio communications, and more particularly to a client device, a network access device, and a procedure for improving channel estimation. Furthermore, the disclosure relates to corresponding methods and a computer program.

BACKGROUND

In new radio, NR, enhanced mobile broad band, eMBB, and ultra reliable and low latency communication, URLLC, are intended for different types of scenarios with respect to target block error rate, BLER, and latency even though they can be unified into the same framework. eMBB may provide a greater data bandwidth complemented by moderate latency improvement compared to 4G long term evolution, LTE. The target BLER for eMBB may be 10 ¹ which is the same as in LTE. URLLC is designed for mission critical applications that can be especially latency-sensitive, and the target BLER for URLLC can be 10 ⁵, which may be more challenging to achieve than the 10 ¹ target in eMBB.

In order to demodulate data received via a physical downlink shared channel, PDSCH, in eMBB or URLLC, a client device may need to estimate the channel of the PDSCH. The channel estimate quantifies how physical phenomena, such as the Doppler shift, affect the data during wireless transmission. The client device may then use the channel estimate to compensate for these effects in the received data.

SUMMARY

This summary is provided to introduce a selection of concepts in a simplified form that are further described below in the detailed description. This summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used to limit the scope of the claimed subject matter.

It is an object to provide a procedure for improving channel estimation in wireless radio communication. The object is achieved by the features of the independent claims. Further implementation forms are provided in the dependent claims, the description and the figures.

According to a first aspect, a client device is configured to: receive from a network access device a physical downlink shared channel, PDSCH, reference signal, RS, and at least one further signal being: physical downlink control channel, PDCCH, data, a PDCCH RS, or PDSCH data; and perform joint channel estimation for the PDSCH data based on the PDSCH

RS and the at least one further signal. With these configurations, the client device can, for example, jointly utilise the PDSCH RS and the at least one further signal for improved channel estimation. Thus, higher effective signal-to-noise ratios may be achieved due to the improved channel estimation, and less radio resources may be needed for RS transmissions.

In an implementation form of the first aspect, the client device is further configured to: receive the PDSCH data from the network access device; and decode the PDSCH data using the performed joint channel estimation. With these configurations, the client device can, for example, utilise the joint channel estimate to decode the PDSCH data more accurately.

In a further implementation form of the first aspect, the client device is further configured to: receive a configuration signal from the network access device, instructing the client device to enable the joint channel estimation; and upon reception of the configuration signal, perform the joint channel estimation. With these configurations, the client device can, for example, collaborate with the network access device in enabling the joint channel estimation. This may, for example, improve radio resource utilisation, since the client device and the network access device may agree when joint channel estimation is used.

In a further implementation form of the first aspect, the client device is further configured to: detect based on the received PDSCH RS and at least one further signal if the joint channel estimation is possible; and perform the joint channel estimation if it is detected to be possible. With these configurations, the client device can, for example, blindly detect if the joint channel estimation is possible. Thus, the client device may use joint channel estimation even without explicit signalling with the network access device.

In a further implementation form of the first aspect, the client device is further configured to detect the joint channel estimation to be possible if all the following are fulfilled: quasi co-location, QCL, between the PDSCH RS and the further signal; same pre-coder for the PDSCH RS and the further signal; same frequency physical resource blocks, PRBs, for the PDSCH RS and the further signal. With these configurations, the client device can, for example, detect if the joint channel estimation may be utilized.

In a further implementation form of the first aspect, the client device is further configured to: construct virtual pilot signals based on the PDCCH data and/or the PDCCH RS; and perform the joint channel estimation based on a dedicated demodulation reference signal, DMRS, and virtual pilot signals. With these configurations, the client device can, for example, utilise the PDCCH data and/or the PDCCH RS with the DMRS for channel estimation. In a further implementation form of the first aspect, the client device is further configured to: transmit a category report to the network access device, wherein the category report indicates capability of the client device to jointly estimate a channel for the PDSCH data. With these configurations, the client device can, for example, signal to the network access device the capabilities of the client device so that the network access device can utilise these capabilities in PDCCH and PDSCH transmissions.

In a further implementation form of the first aspect, the category report further indicates the PDSCH RS and the at least one further signal. With these configurations, the client device can, for example, indicate to the network access device the at least one further signal the client device can use with the PDSCH RS for the joint channel estimation.

In a further implementation form of the first aspect, the client device is further configured to: transmit a confirmation signal to the network access device, wherein the confirmation signal indicates that the client device has enabled the joint channel estimation. With these configurations, the client device can, for example, indicate to the network access device that the joint channel estimation is enabled so that the network access device can take this into account in data and/or RS transmissions.

According to a second aspect, a network access device is configured to: receive a category report from a client device, wherein the category report indicates capability of the client device to perform joint channel estimation for physical downlink shared channel, PDSCH, data based on a PDSCH RS and at least one further signal being: physical downlink control channel, PDCCH, data, a PDCCH reference signal, RS, or the PDSCH data; and schedule the PDCCH and PDSCH to facilitate the joint channel estimation. With these configurations, the network access device can, for example, assist the client device in jointly utilising the PDSCH RS and the at least one further signal for channel estimation. Thus, higher effective signal-to -noise ratios may be achieved due to improved channel estimation, and less radio resources may be needed for RS transmissions.

In an implementation form of the second aspect, the network access device is further configured to: transmit a configuration signal to the client device, instructing the client device to enable the joint channel estimation. With these configurations, the network access device can, for example, collaborate with the client device in enabling the joint channel estimation.

In a further implementation form of the second aspect, the configuration signal comprises a radio resource control, RRC, signal and/or a downlink control information, DCI, signal. With these configurations, the network access device can, for example, transmit signals to the client device with compatibility. In a further implementation form of the second aspect, the configuration signal further configures the PDSCH RS and the at least one further signal. With these configurations, the network access device can, for example, explicitly indicate to the client device which signals the client device may use for the joint channel estimation.

In a further implementation form of the second aspect, the network access device is further configured to: indicate a dedicated demodulation reference signal, DMRS, pattern for the PDSCH by a fixed value indicating a fixed DMRS pattern or by a configurable value dynamically indicating a configurable DMRS pattern. With these configurations, the network access device can, for example, indicate the used DMRS pattern to the client device so that the client device can, for example, find the frequency resources used for the DMRS.

In a further implementation form of the second aspect, the network access device is further configured to: assign at least a part of the PDSCH in a same physical resource block, PRB, with the PDCCH; associate an antenna port of the PDCCH with the PDSCH; and align a coefficient of a pre-coder for each antenna element between the PDCCH and the PDSCH. With these configurations, the network access device can, for example, configure the PDCCH and the PDSCH in such a way that the client device can use PDCCH data and/or RS with the PDSCH RS for joint channel estimation.

According to a third aspect, a method comprises: receiving from a network access device a physical downlink shared channel, PDSCH, reference signal, RS, and at least one further signal being: physical downlink control channel, PDCCH, data, a PDCCH RS, or PDSCH data; and performing joint channel estimation for PDSCH data based on the PDSCH RS and the at least one further signal.

The method according to the third aspect can be extended into implementation forms corresponding to the implementation forms of the client device according to the first aspect. Hence, an implementation form of the method comprises the feature(s) of the corresponding implementation form of the client device.

The advantages of the methods according to the third aspect are the same as those for the corresponding implementation forms of the client device according to the first aspect.

According to a fourth aspect, a method comprises: receiving a category report from a client device, wherein the category report indicates capability of the client device to perform joint channel estimation for physical downlink shared channel, PDSCH, data based on a PDSCH reference signal, RS, and at least one further signal being: physical downlink control channel, PDCCH, data, a PDCCH RS, or the PDSCH data; and scheduling the PDCCH and PDSCH to facilitate the joint channel estimation. The method according to the fourth aspect can be extended into implementation forms corresponding to the implementation forms of the network access device according to the second aspect. Hence, an implementation form of the method comprises the feature(s) of the corresponding implementation form of the network access device.

The advantages of the methods according to the fourth aspect are the same as those for the corresponding implementation forms of the network access device according to the second aspect.

According to a fifth aspect, a computer program is provided, comprising program code configured to perform a method according to the third aspect or the fourth aspect when the computer program is executed on a computer.

Many of the attendant features will be more readily appreciated as they become better understood by reference to the following detailed description considered in connection with the accompanying drawings.

DESCRIPTION OF THE DRAWINGS

The present description will be better understood from the following detailed description read in light of the accompanying drawings, wherein:

FIG. 1 illustrates a schematic representation of a client device configured for joint channel estimation according to an embodiment;

FIG. 2 illustrates a schematic representation of a network access device configured for joint channel estimation according to an embodiment;

FIG. 3 illustrates a schematic representation of a time-frequency diagram for downlink transmission in eMBB according to an embodiment;

FIG. 4 illustrates a schematic representation of a time-frequency diagram for downlink transmission in URFFC according to an embodiment;

FIG. 5 illustrates a schematic representation of a signalling diagram according to an embodiment;

FIG. 6 illustrates a schematic representation of precoding according to an embodiment;

FIG. 7 illustrates a schematic representation of a time- frequency diagram of resources involved in joint channel estimation according to an embodiment;

FIG. 8 illustrates a schematic representation of a flow chart for blind detection according to an embodiment;

FIG. 9 illustrates a schematic representation of simulation results for an extended pedestrian A, EPA, 30 model in URFFC, according to an embodiment; FIG. 10 illustrates a schematic representation of simulation results for an EPA 70 model in URLLC, according to an embodiment;

FIG. 11 illustrates a schematic representation of simulation results for an EPA 120 model in URLLC, according to an embodiment;

FIG. 12 illustrates a schematic representation of simulation results for an EPA 300 model in URLLC, according to an embodiment;

FIG. 13 illustrates a schematic representation of a time-frequency diagram indicating resource element allocation for simulations according to an embodiment;

FIG. 14 illustrates a schematic representation of simulation results for an EPA 30 model in eMBB, according to an embodiment;

FIG. 15 illustrates a schematic representation of simulation results for an EPA 70 model in eMBB, according to an embodiment;

FIG. 16 illustrates a schematic representation of simulation results for an EPA 120 model in eMBB, according to an embodiment; and

FIG. 17 illustrates a schematic representation of simulation results for an EPA 300 model in eMBB, according to an embodiment.

Like references are used to designate like parts in the accompanying drawings.

DETAILED DESCRIPTION

The detailed description provided below in connection with the appended drawings is intended as a description of the embodiments and is not intended to represent the only forms in which the embodiment may be constructed or utilized. However, the same or equivalent functions and structures may be accomplished by different embodiments.

FIG. 1 schematically illustrates a client device 100 also called User Equipment, UE, such as a wireless device, for a wireless communication system according to an embodiment. The client device 100 comprises a processor 101, a transceiver 102, and memory 103. The client device 100 may be configured to perform the functionalities and operations relating to it as described in the embodiments. The wireless communication system may also comprise a network access device 200 as schematically illustrated in FIG. 2. The network access device 200 according to an embodiment may be a transmission and reception point, TRP, or a base station, such as a 5G base station, gNB, which may also comprise a processor 201 and a transceiver 202. The network access device 200 may also be configured to perform the functionalities and operations relating to the network access device 200 as described in the embodiments. According to an embodiment, the client device 100 is configured to receive from the network access device 200 a physical downlink shared channel, PDSCH, reference signal, RS, and at least one further signal being: physical downlink control channel, PDCCH, data, a PDCCH RS or PDSCH data. The client device 100 may be further configured to perform joint channel estimation for PDSCH data based on the PDSCH RS and the at least one further signal.

According to an embodiment, the client device 100 may be further configured to receive the PDSCH data from the network access device and decode the PDSCH data using the performed joint channel estimation. The client device 100 may be further configured to receive a configuration signal from the network access device 200, instructing the client device 100 to enable the joint channel estimation and upon reception of the configuration signal, perform the joint channel estimation. The client device 100 may be further configured to detect based on the received PDSCH RS and at least one further signal if the joint channel estimation is possible; and perform the joint channel estimation if it is detected to be possible.

According to an embodiment, the network access device 200 is configured to receive a category report from the client device 100, wherein the category report indicates capability of the client device 100 to perform joint channel estimation for physical downlink shared channel, PDSCH, data based on a PDSCH RS and at least one further signal being: physical downlink control channel, PDCCH, data, a PDCCH reference signal, RS, or the PDSCH data. The network access device 200 may be further configured to schedule the PDCCH and PDSCH to facilitate the joint channel estimation.

To facilitate the joint channel estimation, the network access device 200 may, for example, assign at least part of the PDSCH in the same physical resource blocks, PRBs, with the PDCCH, associate an antenna port of the PDCCH and of the PDSCH, and/or align the coefficient of a pre-coder for each antenna element between the PDCCH and the PDSCH.

An embodiment may improve physical layer performance, such as channel estimation, by transmitting and receiving the PDCCH and the PDSCH jointly. For example, the client device 100 may perform joint channel estimation using a PDCCH RS with PDCCH data, a PDSCH RS, and/or PDSCH data to estimate the channel of the PDSCH. A client device 100 may comprise an advanced receiver that may perform the joint channel estimation, or the advanced receiver may refer to the capability of the client device 100 to jointly estimate the channel. Thus, the PDCCH can be utilised beyond only using it to convey control information. This may be beneficial, since the reliability of the PDCCH can be higher than BLER < 10^-5. The advanced receiver can also achieve improved channel estimation performance. With collaboration between the client device 100 and the network access device 200 in addition to the advanced receiver, performance may be improved by jointly processing the RS and data of the PDCCH and PDSCH. The collaboration may comprise, for example, reporting and signalling between the client device 100 and the network access device 200.

The PDSCH RS may be used by default for PDSCH channel estimation. If data is going to be explored in the joint process, the data should be decoded, demodulated, or estimated. For example, if the client device 100 is capable of jointly processing PDSCH data and the PDSCH RS, the PDSCH data can be explored, for example, in an incremental fashion, in an iterative fashion, or both. For example, in an incremental way, data a can be estimated based on the RS, data b can be estimated based on the RS and the recovered data a, and data c can be estimated based on the RS and the recovered data a, b, ... . In an iterative way, data {a, b } can be estimated based on the RS, and then re-estimated based on the RS plus the recovered data {a, b }. In an incremental and iterative way, data {a, b } can be estimated based on the RS, and data {b, c } can be estimated based on the RS plus the recovered data {a, b}.

The embodiment discloses a method and a device for performance improvement of channel estimation/decoding. The client device 100 may comprise an advanced receiver to perform PDSCH channel estimation via exploring the PDCCH. Corresponding procedures and signalling between the network access device 200 and the client device 100 are introduced in various embodiments.

The client device 100 can detect if the PDCCH and PDSCH are Quasi Co-Located, QCL, and scheduled with the same pre-coder and frequency physical resource blocks, PRBs. After a cyclic redundancy check, CRC pass of the PDCCH, an advanced receiver can be implemented with the PDCCH RS, PDCCH data or both applied to PDSCH channel estimation together with the PDSCH DMRS. In case of single layer transmission, the additional complexity may be moderate due to quadrature phase shift keying, QPSK, modulation. In the case of multiple layer transmission, it can also be handled by either joint or per-layer spatial processing.

The client device 100 may report capability in terms of, for example, the client device category of the advanced receiver to the network access device 200. The network access device 200 can receive the information that the client device 100 can process the DMRS jointly with the PDCCH reference signal and/or data. The network access device 200 may associate an antenna port of the PDCCH and PDSCH and make sure that the same pre-coder is applied to each antenna element between the PDCCH and the PDSCH either based on RRC signalling and/or DCI. When receiving the PDCCH and PDSCH, the client device 100 may apply the advanced receiver according to signalling from the network access device 200 or blind detection. The embodiment may be useful for URLLC due to the desired PDSCH performance improvement.

The client device 100 and the network access device 200 may further comprise other components that are not illustrated in FIGs. 1 and 2. The client device 100 may communicate with, for example, the network access device 200 using the transceiver 102. The network access device 200 may communicate with, for example, a single or a plurality of client devices 100 using the transceiver 202. The client device 100 may communicate with, for example, a single or a plurality of network access devices 200 using the transceiver 102. The client device 100 may also comprise a plurality of transceivers 102 and communicate with the plurality of network access devices 200 using the plurality of transceivers 102. For example, the client device 100, such as a mobile phone, can be served by one gNodeB or multiple gNodeBs. For example, in dual connectivity, the client device 100 can be served by two gNodeBs. In carrier aggregation, the client device 100 can be served by more than one carrier.

The client device 100 may be any of a User Equipment (UE) in Long Term Evolution (LTE) or 5G new radio (NR), mobile station (MS), wireless terminal, or mobile terminal which is enabled to communicate wirelessly in a wireless communication system, sometimes also referred to as a cellular radio system. The client device 100 may further be referred to as a mobile telephone, a cellular telephone, a computer tablet or a laptop with wireless capability. The client device 100 in the present context may be, for example, a portable, pocket-storable, hand-held, computer-comprised, or vehicle-mounted mobile device, enabled to communicate voice or data, via a radio access network, with another entity, such as another receiver or a server. The client device 100 can be a Station (STA) which is any device that contains an IEEE 802.11 -conformant Media Access Control (MAC) and Physical Layer (PHY) interface to the Wireless Medium (WM).

The network access device 200 may be a transmission or reception point, TRP, or a NR 5G base station, gNB. The network access device 200 may be a base station, a (radio) network node or an access node or an access point or a base station, e.g., a Radio Base Station (RBS), which in some networks may be referred to as a transmitter,“eNB”,“eNodeB”,“gNB”, “gNodeB”,“NodeB”, or“B node”, depending on the technology and terminology used. The radio network nodes may be of different classes such as, e.g., macro eNodeB, home eNodeB or pico base station, based on transmission power and thereby also cell size. The radio network node can be a Station (STA) which is any device that contains an IEEE 802.11 -conformant Media Access Control (MAC) and Physical Layer (PHY) interface to the Wireless Medium (WM). FIG. 3 illustrates a schematic representation of a time-frequency diagram for downlink,

DL, transmission in eMBB according to an embodiment. In FIG. 3 and in similar figures herein, time runs along the horizontal direction, and frequency runs along the vertical direction. Each square in FIG. 3 may correspond to a single orthogonal frequency-division multiplexing, OFDM, subcarrier frequency in the frequency dimension and a single OFDM symbol in the time dimension. Each such square may be referred to as a resource element. FIG. 3 comprises 14 OFDM symbols. Such collection of OFDM symbols may be referred to as a subframe.

Herein, the pattern illustrated in each resource element may indicate a function the resource element is allocated for. For example, in FIG. 3 resource elements illustrated with white colour and without a pattern may be allocated for data transmission even though all such resource elements may not be marked with a reference number for clarity purposes.

Each resource element may be assigned for a certain function. For example, in FIG. 3, first two OFDM symbols (0 and 1) are assigned for a physical downlink control channel, PDCCH, 301. OFDM symbol 2 is assigned for reference signals, RS, and the reference signals are divided into code division multiplexing, CDM, group 0 302 2 and CDM group 1 302 1. The reference signals may be, for example, dedicated demodulation reference signals, DMRSs. The reference signals belonging to CDM group 0 302 2 or to CDM group 1 302 1 may be referred to as reference signals. Some resource elements are also assigned for data 304. The data 304 may be, for example, physical downlink shared channel, PDSCH, data.

FIG. 4 illustrates a schematic representation of a time-frequency diagram for downlink, DF, transmission in URFFC according to an embodiment. The time- frequency diagram presented in FIG. 4 may be similar to that presented for eMBB in FIG. 3. However, the diagram in FIG. 4 comprises only 7 OFDM symbols. Such collection of OFDM symbols may be referred to as a resource block. Each subframe may comprise two resource blocks. URFFC may have only one DMRS symbol 302 1 for channel estimation due to overhead considerations. Other DMRSs may be configured, for example, on OFDM symbol 4. This may only be desirable for edge cases with extremely high Doppler shift due to the additional 20% DMRS overhead. Furthermore, less OFDM symbols may be assigned for PDSCH data 304 in URFFC compared to eMBB as can be seen by comparing FIG. 3 with FIG. 4.

In order to decode the PDSCH data 304, the client device 100 may need to first decode the PDCCH data 301 in order to obtain related control information of the DMRSs 302 1, 302 2 and the PDSCH 304. The control information may comprise, for example, a frequency domain resource assignment which may indicate where the DMRS 302 1, 302 2 and PDSCH 304 are allocated in frequency. According to an embodiment, the DMRS pattern or simply pattern may refer to the manner in which resource elements in frequency and/or in time are allocated for reference signals, such as demodulation reference signals. For example, the fact that OFDM symbols 2 and 11 are used for DMRSs in FIG. 3 may be referred to as a DMRS pattern.

FIG. 5 illustrates a schematic representation of a signalling diagram according to an embodiment. According to an embodiment, the client device 100 may be further configured to transmit a category report to the network access device 200, wherein the category report indicates capability of the client device 100 to jointly estimate a channel for the PDSCH data. The category report may further indicate the PDSCH RS and the at least one further signal.

Since channel estimation and throughput performance can be significant from the advanced receiver technique, a specific client device category with different levels of capability can be defined and reported to the network access device 200. For example, as is illustrated in FIG. 5, the client device 100 may transmit its capability information to the network access device 200 using a category report 501. Based on the received category report 501 the in operation 502, the network access device 200 may update its information on client device 100 and for example derive information on how to optimally place the reference signals to fully take advantage of the capabilities of the client device 100.

According to an embodiment, the network access device 200 is further configured to transmit a configuration signal to the client device 100, instructing the client device 100 to enable the joint channel estimation. The configuration signal may comprise a radio resource control, RRC, signal and/or a downlink control information, DCI, signal. The configuration signal may further configure the PDSCH RS and the at least one further signal. For example, as is illustrated in FIG. 5, the network access device 200 may indicate the client device 100 to enable or disable the advanced receiver using enable/disable advanced receiver signalling 503. The network access device 200 may use, for example, radio resource control, RRC, signalling and/or downlink control information, DCI for the enable/disable signalling 503. Furthermore, information like DMRS density (pattern in frequency and/or time domain) indicated by the original field from the RRC signal and/or DCI may be implicitly adjusted depending on whether the advanced receiver is enabled or not.

According to an embodiment, the network access device 200 is configured to indicate a dedicated demodulation reference signal, DMRS, pattern for the PDSCH by a fixed value indicating a fixed DMRS pattern or by a configurable value dynamically indicating a configurable DMRS pattern. According to an embodiment, the client device 100 can be further configured to transmit a confirmation signal to the network access device 200, wherein the confirmation signal indicates that the client device 100 has enabled the joint channel estimation. For example, as is illustrated in FIG. 5, the client device 100 may optionally transmit a confirmation signal 504 to the network access device 200.

The category report 501 may indicate different levels of the advanced receiver to the network access device 200. These levels may comprise, for example:

capability to jointly process the PDCCH RS and PDSCH RS; and/or

capability to jointly process the PDCCH RS, PDCCH data and the PDSCH RS; and/or

capability to jointly process PDSCH data and the PDSCH RS; and/or

capability to jointly process the PDCCH RS, PDCCH data, PDSCH data and the PDSCH RS.

Correspondingly, the network access device 200 may in above mentioned step 502 adjust the PDCCH and PDSCH so that a join estimation at the client device 100 is possible. In addition the network access 200 can configure the client device 100 to enable/disable the advanced receiver on each level in step 503. In addition other related information can also be configured in step 502 and then signalled to the client device 100 e.g. in step 503. For example, the enable/disable signalling 503 may enable joint channel estimation using PDSCH data and the PDSCH RS. In this case, new PDSCH RS (DMRS) density in time (indicated by DL- DMRS-config-type, DL-DMRS-add-pos, DL-DMRS-typeA-pos in 3 GPP TS 38.211, 7.4.1.1.2.) can be configured implicitly as fixed parameters or indicated explicitly by the network access device 200 to the client device 100 as configurable parameters for example in step 503. For example one may configure DL-DMRS-add-pos = max( DL-DMRS-add-pos-X, 0), where X may be a fixed value (no need to be configured explicitly) or a dynamic value configured together with the signalling in step 503. Implicit configuring shall be understood as, when the client device 100 receives the instruction to activate its advanced receiver it already knows which configuration to use e.g. based on a definition in the relevant standard and can configure this configuration without explicit signalling.

The enable/disable signalling 503 may enable joint channel estimation using the PDCCH RS (and data) and PDSCH RS. In this case, antenna port association and precoding alignment between the PDCCH and the PDSCH can be configured and scheduled by the network access device 200. According to an embodiment, antenna port association and precoding alignment may comprise that all antenna elements, occupied by the PDCCH and the PDSCH, are associated, and that for each antenna element the same precoding coefficient is applied between the PDCCH and PDSCH for each group of resources (for example one physical

RB or one Precoding Resource block Group, PRG). With antenna port association and precoding alignment between the PDCCH and the PDSCH, an effective channel of the PDCCH and the PDSCH at the client device 100 side can be jointly estimated, for example, as the same concept of the precoding resource block Group, PRG, in the embodiment.

The network access device 200 may schedule the PDCCH and the PDSCH so that the scheduling 505 takes advantage of the joint channel estimation. The client device 100 may then use the advanced receiver 506 to perform joint channel estimation.

FIG. 6 illustrates a schematic representation of precoding according to an embodiment. In this embodiment, there are P antenna elements in total and the precoding coefficients p_n 601 are the same across the whole RB of the PDCCH and PDSCH for each antenna element.

FIG. 7 illustrates a schematic representation of a time- frequency diagram of resources involved in joint channel estimation according to an embodiment. FIG. 7 illustrates the resource element allocation for PDCCH data 301, PDCCH RS 303, PDSCH data 304, and PDSCH RS 302. Such resource element allocation may be configured for each transmitted layer and received antenna. In the advanced receiver, the channel for the PDSCH data 304 can be estimated based on the PDSCH RS 302, such as DMRS, together with at least one of the PDCCH RS 303, PDCCH data 301 and PDSCH data 304.

The client device 100 may enable the advanced receiver to jointly process PDSCH data and the PDSCH RS, based on a reconfigured DMRS pattern, for example, if signalled by the network access device 200. For the advanced receiver to jointly process the PDSCH and PDCCH, the client device 100 may enable it either based on network access device 200 configuration or blind detection. If the advanced receiver is configured by the network access device 200, it can be applied for physical RBs overlapped between the PDCCH and the PDSCH.

FIG. 8 illustrates a schematic representation of a flow chart for a blind detection in client device 100 according to an embodiment. If the advanced receiver is not explicitly configured by the network access device 200, the client device 100 may firstly detect if all conditions are satisfied for each physical RB, and secondly apply joint channel estimation using the advanced receiver.

In operation 801, the client device 100 decodes the PDCCH, and performs a cyclic redundancy check, CRC, on the PDCCH data in operation 802. If the CRC is not passed, the client device 100 may skip the slot in operation 803. If the CRC is passed, the client device 100 may fetch DCI configuration in operation 804. Based on RRC configuration in operation 805, DCI configuration in 804, PDSCH RS,

PDCCH RS and/or PDCCH data, the client device 100 may check if joint channel estimation is possible in following operations 806, 807, and 808. In operation 806, the client device 100 may check if the PDCCH and the PDSCH are QCL (quasi co-located). In operation 807, the client device 100 can check if the PDCCH and the PDSCH share the same pre-coder. This can be performed, for example, via a correlation match. In operation 808, the client device 100 can check if the PDCCH and the PDSCH comprise the same frequency PRBs based on, for example, RRC and DCI configuration. This can be performed using, for example, CORESET-pre-coder- granularity, CORESET-REG-bundle-size, frequency domain resource assignment, etc.

The QCL condition may be satisfied if the same Doppler shift and delay spread can be assumed for the PDCCH and the PDSCH. The same pre-coder condition may be satisfied if channel correlation of the effective channel is matched across all resources, regardless of whether it belongs to the PDCCH or the PDSCH. The same frequency PRBs condition may be satisfied if a PRB occupied by the PDSCH is also occupied by the PDCCH.

If all the aforementioned conditions are met, the client device 100 may construct virtual pilots based on PDCCH data and/or the RS in operation 809. The client device 100 may also perform DMRS extraction in operation 811. Joint channel estimation can be performed based on the DMRS and the virtual pilots in operation 812. (Normal) channel estimation based on the DMRS only can be performed for PRBs in operation 810 when at least one of the mentioned conditions is not satisfied.

According to an embodiment, the client device 100 is configured to detect the joint channel estimation to be possible if all the following are fulfilled: quasi co-location, QCL, between the PDSCH RS and the further signal; same pre-coder for the PDSCH RS and the further signal; same frequency physical resource blocks, PRBs, for the PDSCH RS and the further signal. The client device 100 may be further configured to construct virtual pilot signals based on the PDCCH data and/or the PDCCH RS; and perform the joint channel estimation based on a dedicated demodulation reference signal, DMRS, and virtual pilot signals.

According to an embodiment, the network access device 200 is configured to assign at least a part of the PDSCH in a same physical resource block, PRB, with the PDCCH, associate an antenna port of the PDCCH with the PDSCH, and align a coefficient of a pre-coder for each antenna element between the PDCCH and the PDSCH.

FIG. 9 illustrates a schematic representation of simulation results for an extended pedestrian A, EPA, 30 model in URLLC, according to an embodiment. Resource element allocation used for this simulation may be similar to that presented in FIG. 4. The DMRS may occupy CDM group 0 302 2 and CDM group 1 302 1. Curve 901 illustrates the effective signal-to -noise ratio, SNR, as a function of the SNR of the channel when an embodiment is used. Curve 902 illustrates the effective SNR as a function of the SNR of the channel when the embodiment is not used.

FIG. 10 illustrates a schematic representation of simulation results for an EPA 70 model in URLLC, according to an embodiment. Resource element allocation used for this simulation may be similar to that presented in FIG. 4. The DMRS may occupy CDM group 0 302 2 and CDM group 1 302 1. Curve 1001 illustrates the effective SNR as a function of the SNR of the channel when an embodiment is used. Curve 1002 illustrates the effective SNR as a function of the SNR of the channel when the embodiment is not used.

FIG. 11 illustrates a schematic representation of simulation results for an EPA 120 model in URFFC, according to an embodiment. Resource element allocation used for this simulation may be similar to that presented in FIG. 4. The DMRS may occupy CDM group 0 302 2 and CDM group 1 302 1. Curve 1101 illustrates the effective SNR as a function of the SNR of the channel when an embodiment is used. Curve 1102 illustrates the effective SNR as a function of the SNR of the channel when the embodiment is not used.

FIG. 12 illustrates a schematic representation of simulation results for an EPA 300 model in URFFC, according to an embodiment. Resource element allocation used for this simulation may be similar to that presented in FIG. 4. The DMRS may occupy CDM group 0 302 2 and CDM group 1 302 1. Curve 1201 illustrates the effective SNR as a function of the SNR of the channel when an embodiment is used. Curve 1202 illustrates the effective SNR as a function of the SNR of the channel when the embodiment is not used.

FIG. 13 illustrates a schematic representation of a time-frequency diagram indicating resource element allocation for simulations according to an embodiment. This resource element allocation is used for the eMBB simulations presented below. The DMRS may occupy CDM group 0 302 2 and CDM group 1 302 1.

FIG. 14 illustrates a schematic representation of simulation results for an EPA 30 model in eMBB, according to an embodiment. Resource element allocation used for this simulation may be similar to that presented in FIG. 13. Curve 1301 illustrates the effective SNR as a function of the SNR of the channel when an embodiment is used. Curve 1302 illustrates the effective SNR as a function of the SNR of the channel when the embodiment is not used.

FIG. 15 illustrates a schematic representation of simulation results for an EPA 70 model in eMBB, according to an embodiment. Resource element allocation used for this simulation may be similar to that presented in FIG. 13. Curve 1401 illustrates the effective SNR as a function of the SNR of the channel when an embodiment is used. Curve 1402 illustrates the effective SNR as a function of the SNR of the channel when the embodiment is not used.

FIG. 16 illustrates a schematic representation of simulation results for an EPA 120 model in eMBB, according to an embodiment. Resource element allocation used for this simulation may be similar to that presented in FIG. 13. Curve 1501 illustrates the effective SNR as a function of the SNR of the channel when an embodiment is used. Curve 1502 illustrates the effective SNR as a function of the SNR of the channel when the embodiment is not used.

FIG. 17 illustrates a schematic representation of simulation results for an EPA 300 model in eMBB, according to an embodiment. Resource element allocation used for this simulation may be similar to that presented in FIG. 13. Curve 1601 illustrates the effective SNR as a function of the SNR of the channel when an embodiment is used. Curve 1602 illustrates the effective SNR as a function of the SNR of the channel when the embodiment is not used.

The functionality described herein can be performed, at least in part, by one or more computer program product components such as software components. According to an embodiment, the network access device 200 and/or the client device 100 comprise the processor 101, 201 configured by the program code when executed to execute the embodiments of the operations and functionality described. Alternatively, or in addition, the functionality described herein can be performed, at least in part, by one or more hardware logic components. For example, and without limitation, illustrative types of hardware logic components that can be used include Field-programmable Gate Arrays (FPGAs), Program-specific Integrated Circuits (ASICs), Program-specific Standard Products (ASSPs), System-on-a-chip systems (SOCs), Complex Programmable Fogic Devices (CPFDs), Graphics Processing Units (GPUs).

Any range or device value given herein may be extended or altered without losing the effect sought. Also any embodiment may be combined with another embodiment unless explicitly disallowed.

Although the subject matter has been described in language specific to structural features and/or acts, it is to be understood that the subject matter defined in the appended claims is not necessarily limited to the specific features or acts described above. Rather, the specific features and acts described above are disclosed as embodiments of implementing the claims and other equivalent features and acts are intended to be within the scope of the claims.

It will be understood that the benefits and advantages described above may relate to one embodiment or may relate to several embodiments. The embodiments are not limited to those that solve any or all of the stated problems or those that have any or all of the stated benefits and advantages. It will further be understood that reference to 'an' item may refer to one or more of those items. The term‘and/or’ may be used to indicate that one or more of the cases it connects may occur. Both, or more, connected cases may occur, or only either one of the connected cases may occur.

The operations of the methods described herein may be carried out in any suitable order, or simultaneously where appropriate. Additionally, individual blocks may be deleted from any of the methods without departing from the spirit and scope of the subject matter described herein. Aspects of any of the embodiments described above may be combined with aspects of any of the other embodiments described to form further embodiments without losing the effect sought.

The term 'comprising' is used herein to mean including the method, blocks or elements identified, but that such blocks or elements do not comprise an exclusive list and a method or apparatus may contain additional blocks or elements.

It will be understood that the above description is given by way of example only and that various modifications may be made by those skilled in the art. The above specification, embodiments and data provide a complete description of the structure and use of exemplary embodiments. Although various embodiments have been described above with a certain degree of particularity, or with reference to one or more individual embodiments, those skilled in the art could make numerous alterations to the disclosed embodiments without departing from the spirit or scope of this specification.

Claims

1. A client device (100), configured to:

receive from a network access device (200) a physical downlink shared channel, PDSCH, reference signal, RS, (302) and at least one further signal being: physical downlink control channel, PDCCH, data (301), a PDCCH RS (303), or PDSCH data (304); and

perform joint channel estimation for the PDSCH data based on the PDSCH RS and the at least one further signal.

2. The client device of claim 1, further configured to:

receive the PDSCH data from the network access device; and

decode the PDSCH data using the performed joint channel estimation.

3. The client device of claim 1 or 2, further configured to:

receive a configuration signal (503) from the network access device, instructing the client device to enable the joint channel estimation; and

upon reception of the configuration signal, perform the joint channel estimation.

4. The client device of claim 1 or 2, further configured to:

detect based on the received PDSCH RS and at least one further signal if the joint channel estimation is possible; and

perform the joint channel estimation if it is detected to be possible.

5. The client device of claim 4, further configured to detect the joint channel estimation to be possible if all the following are fulfilled:

quasi co-location, QCL, between the PDSCH RS and the further signal;

same pre-coder for the PDSCH RS and the further signal;

same frequency physical resource blocks, PRBs, for the PDSCH RS and the further signal.

6. The client device of any preceding claim, further configured to:

construct virtual pilot signals based on the PDCCH data and/or the PDCCH RS; and perform the joint channel estimation based on a dedicated demodulation reference signal, DMRS, and virtual pilot signals.

7. The client device of any preceding claim, further configured to:

transmit a category report (501) to the network access device, wherein the category report indicates capability of the client device to jointly estimate a channel for the PDSCH data.

8. The client device of claim 7, wherein the category report further indicates the PDSCH RS and the at least one further signal.

9. The client device of any preceding claim, further configured to:

transmit a confirmation signal (504) to the network access device, wherein the confirmation signal indicates that the client device has enabled the joint channel estimation.

10. A network access device (200), configured to:

receive a category report (501) from a client device (100), wherein the category report indicates capability of the client device to perform joint channel estimation for physical downlink shared channel, PDSCH, data (304) based on a PDSCH reference signal, RS, (302) and at least one further signal being: physical downlink control channel, PDCCH, data (301), a PDCCH RS (303), or the PDSCH data; and

schedule the PDCCH and PDSCH to facilitate the joint channel estimation.

11. The network access device of claim 10, further configured to:

transmit a configuration signal (503) to the client device, instructing the client device to enable the joint channel estimation.

12. The network access device of claim 11, wherein the configuration signal comprises a radio resource control, RRC, signal and/or a downlink control information, DCI, signal.

13. The network access device of any of claims 10 - 12, wherein the configuration signal further configures the PDSCH RS and the at least one further signal.

14. The network access device of any of claims 10 - 13, further configured to:

indicate a dedicated demodulation reference signal, DMRS, pattern for the PDSCH by a fixed value indicating a fixed DMRS pattern or by a configurable value dynamically indicating a configurable DMRS pattern.

15. The network access device of any of claims 10 - 14, further configured to:

assign at least a part of the PDSCH in a same physical resource block, PRB, with the

PDCCH;

associate an antenna port of the PDCCH with the PDSCH; and

align a coefficient of a pre-coder for each antenna element between the PDCCH and the PDSCH.

16. A method, comprising:

receiving from a network access device a physical downlink shared channel, PDSCH, reference signal, RS, and at least one further signal being: physical downlink control channel, PDCCH, data, a PDCCH RS, or PDSCH data; and

performing joint channel estimation for PDSCH data based on the PDSCH RS and the at least one further signal.

17. A method, comprising:

receiving a category report from a client device, wherein the category report indicates capability of the client device to perform joint channel estimation for physical downlink shared channel, PDSCH, data based on a PDSCH reference signal, RS, and at least one further signal being: physical downlink control channel, PDCCH, data, a PDCCH RS, or the PDSCH data; and

scheduling the PDCCH and PDSCH to facilitate the joint channel estimation.

18. A computer program comprising program code configured to perform a method according to claim 16 or claim 17 when the computer program is executed on a computer.