WO2020056650A1

WO2020056650A1 - Network assisted feedback weight detection for nonlinear precoding

Info

Publication number: WO2020056650A1
Application number: PCT/CN2018/106573
Authority: WO
Inventors: Xuning SHAO; Eugene Visotsky; Frederick Vook; Tianyang QI
Original assignee: Nokia Shanghai Bell Co., Ltd.; Nokia Solutions And Networks Oy; Nokia Technologies Oy
Priority date: 2018-09-19
Filing date: 2018-09-19
Publication date: 2020-03-26
Also published as: CN112771786B; CN112771786A

Abstract

In accordance with example embodiments of the invention as described herein there is at least a method and apparatus to perform identifying, by a user equipment of a communication network, more than one data layer sequence associated with feedback weights in a transmission from a network node of the communication network, wherein the more than one data layer sequence is ordered for successive precancellation of interference; and performing, by the user equipment, interference rejection for communications using the more than one data layer sequence. In addition to perform sending, by a network node of a communication network, towards a user equipment more than one data layer sequence associated with feedback weights in a transmission from a network node of the communication network, wherein the more than one data layer sequence is ordered for successive precancellation of interference, wherein the more than one data layer sequence is for use by the user equipment to perform interference rejection for communications using the more than one data layer sequence.

Description

NETWORK ASSISTED FEEDBACK WEIGHT DETECTION FOR NONLINEAR PRECODING

TECHNICAL FIELD:

The teachings in accordance with the exemplary embodiments of this invention relate generally to an enhanced network assisted feedback weight detection scheme and, more specifically, relate to an enhanced network assisted feedback weight detection scheme supporting improved interference measurement at the receiver.

BACKGROUND:

This section is intended to provide a background or context to the invention that is recited in the claims. The description herein may include concepts that could be pursued, but are not necessarily ones that have been previously conceived or pursued. Therefore, unless otherwise indicated herein, what is described in this section is not prior art to the description and claims in this application and is not admitted to be prior art by inclusion in this section.

Certain abbreviations that may be found in the description and/or in the Figures are herewith defined as follows:

NR New Radio

NLP Non-linear precoding

MU Multi-User

MIMO Multiple Input Multiple Output

THP Tomlinson-Harashima Precoding

TX Transmit

RX Receive

UE User Equipment

DMRS Demodulation Reference Signal

MRC Maximal Ratio Combining

MMSE Minimum Mean Square Error

LLR Log-likelihood Ratio

CSI Channel State Information

DCI Downlink Control Information

LoS Line-of-sight

NLoS Non-line-of-sight

In multi-antenna techniques precoding is used to map the modulation symbols onto the different antennas. The type of precoding depends on the multi-antenna technique used as well as on the number of layers and the number of antenna ports. The aim with precoding is to achieve the best possible data reception at the receiver.

It is noted that a transmission or signaling will be influenced by interference and fading of various types, which can also be seen as some type of coding caused by the radio channel. To handle this, known reference signals may be communicated together with data, and used by the receiver for reducing or eliminating interference for signaling transmission and/or demodulation.

Example embodiments of the invention work to enhance such signalling for addressing such interference.

SUMMARY:

In an example aspect of the invention, there is a method comprising: identifying, by a user equipment of a communication network, more than one data layer sequence associated with feedback weights in a transmission from a network node of the communication network, wherein the more than one data layer sequence is ordered for successive precancellation of interference; and performing, by the user equipment, interference rejection for communications using the more than one data layer sequence.

A further example embodiment is a method comprising the method of the previous paragraph, wherein at least one antenna port is assigned to each of the more than one data layer sequence, wherein the at least one antenna port comprises at least one demodulation reference signal port, wherein the at least one demodulation reference signal port of a data layer identifies whether the data layer is associated with an upstream interference layer or a downstream interference layer, wherein the interference rejection is performed based on the feedback weights of the upstream interference layer and the downstream interference layer of the more than one data layer sequence, there is blindly detecting a feedback weight associated with an upstream interference layer sequence, wherein the detecting the feedback weight is based on a residual interference for the data layer sequence being zero, wherein an antenna port sequence of a target data layer sequence for the user equipment is received by the user equipment in downlink control information via one of a radio resource control configuration or a medium access control element, wherein the interference rejection comprises using the antenna port sequence to determine at least one interfering data layer sequence for use by the user equipment in upstream communication, wherein the at least one demodulation reference signal port is assigned according to a non-linear precoding layer order of the more than one data layer sequence, there is receiving from the network node via downlink signaling a one-bit indicator indicating that a data layer sequence port order corresponds to the non-linear precoding layer order, and wherein the one-bit indicator is indicating whether a demodulation reference signal port is corresponding to a precancellation order.

In an example aspect of the invention, there is an apparatus, such as a user side apparatus, comprising means for identifying, by a user equipment of a communication network, more than one data layer sequence associated with feedback weights in a transmission from a network node of the communication network, wherein the more than one data layer sequence is ordered for successive precancellation of interference; and means for performing, by the user equipment, interference rejection for communications using the more than one data layer sequence.

A further example embodiment is an apparatus comprising the apparatus of the previous paragraph, wherein at least one antenna port is assigned to each of the more than one data layer sequence, wherein the at least one antenna port comprises at least one demodulation reference signal port, wherein the at least one demodulation reference signal port of a data layer identifies whether the data layer is associated with an upstream interference layer or a downstream interference layer, wherein the interference rejection is performed based on the feedback weights of the upstream interference layer and the downstream interference layer of the more than one data layer sequence, there is means for blindly detecting a feedback weight associated with an upstream interference layer sequence, wherein the detecting the feedback weight is based on a residual interference for the data layer sequence being zero, wherein an antenna port sequence of a target data layer sequence for the user equipment is received by the user equipment in downlink control information via one of a radio resource control configuration or a medium access control element, wherein the interference rejection comprises using the antenna port sequence to determine at least one interfering data layer sequence for use by the user equipment in upstream communication, wherein the at least one demodulation reference signal port is assigned according to a non-linear precoding layer order of the more than one data layer sequence, there is means for receiving from the network node via downlink signaling a one-bit indicator indicating that a data layer sequence port order corresponds to the non-linear precoding layer order, and wherein the one-bit indicator is indicating whether a demodulation reference signal port is corresponding to a precancellation order.

In an example aspect of the invention, there is an apparatus, such as a user side apparatus, comprising: at least one processor; and at least one memory including computer program code, where the at least one memory and the computer program code are configured, with the at least one processor, to cause the apparatus to at least: identify, by a user equipment of a communication network, more than one data layer sequence associated with feedback weights in a transmission from a network node of the communication network, wherein the more than one data layer sequence is ordered for successive precancellation of interference; and perform, by the user equipment, interference rejection for communications using the more than one data layer sequence.

A further example embodiment is an apparatus comprising the apparatus of the previous paragraph, wherein at least one antenna port is assigned to each of the more than one data layer sequence, wherein the at least one antenna port comprises at least one demodulation reference signal port, wherein the at least one demodulation reference signal port of a data layer identifies whether the data layer is associated with an upstream interference layer or a downstream interference layer, wherein the interference rejection is performed based on the feedback weights of the upstream interference layer and the downstream interference layer of the more than one data layer sequence, wherein the at least one memory including the computer program code is configured with the at least one processor to cause the apparatus to: blindly detect a feedback weight associated with an upstream interference layer sequence, wherein the detecting the feedback weight is based on a residual interference for the data layer sequence being zero, wherein an antenna port sequence of a target data layer sequence for the user equipment is received by the user equipment in downlink control information via one of a radio resource control configuration or a medium access control element, wherein the interference rejection comprises using the antenna port sequence to determine at least one interfering data layer sequence for use by the user equipment in upstream communication, wherein the at least one demodulation reference signal port is assigned according to a non-linear precoding layer order of the more than one data layer sequence, wherein the at least one memory including the computer program code is configured with the at least one processor to cause the apparatus to: receive from the network node via downlink signaling a one-bit indicator indicating that a data layer sequence port order corresponds to the non-linear precoding layer order, and wherein the one-bit indicator is indicating whether a demodulation reference signal port is corresponding to a precancellation order.

In another example aspect of the invention, there is a method comprising: sending, by a network node of a communication network, towards a user equipment more than one data layer sequence associated with feedback weights in a transmission from a network node of the communication network, wherein the more than one data layer sequence is ordered for successive precancellation of interference, wherein the more than one data layer sequence is for use by the user equipment to perform interference rejection for communications using the more than one data layer sequence.

A further example embodiment is a method comprising the method of the previous paragraph, wherein at least one antenna port is assigned to each of the more than one data layer sequence, wherein the at least one antenna port comprises at least one demodulation reference signal port, wherein the at least one demodulation reference signal port of a data layer identifies whether the data layer is associated with an upstream interference layer or a downstream interference layer, wherein the interference rejection is performed based on the feedback weights of the upstream interference layer and the downstream interference layer of the more than one data layer sequence, wherein the interference rejection comprises blind detection of a feedback weight associated with an upstream interference layer sequence, wherein the detection of the feedback weight is based on a residual interference for the data layer sequence being zero, wherein an antenna port sequence of a target data layer sequence for the user equipment is sent to the user equipment in downlink control information via one of a radio resource control configuration or a medium access control element, wherein the interference rejection comprises using the antenna port sequence to determine at least one interfering data layer sequence for use by the user equipment, wherein the at least one demodulation reference signal port is assigned according to a non-linear precoding layer order of the more than one data layer sequence, and there is sending by the network node to the user equipment via downlink signaling a one-bit indicator indicating that a data layer sequence port order corresponds to the non-linear precoding layer order, wherein the one-bit indicator is indicating whether a demodulation reference signal port is corresponding to a precancellation order.

In another example aspect of the invention, there is an apparatus such as a network side apparatus comprising: means for sending, by a network node of a communication network, towards a user equipment more than one data layer sequence associated with feedback weights in a transmission from a network node of the communication network, wherein the more than one data layer sequence is ordered for successive precancellation of interference, wherein the more than one data layer sequence is for use by the user equipment to perform interference rejection for communications using the more than one data layer sequence.

A further example embodiment is an apparatus comprising the apparatus of the previous paragraph, wherein at least one antenna port is assigned to each of the more than one data layer sequence, wherein the at least one antenna port comprises at least one demodulation reference signal port, wherein the at least one demodulation reference signal port of a data layer identifies whether the data layer is associated with an upstream interference layer or a downstream interference layer, wherein the interference rejection is performed based on the feedback weights of the upstream interference layer and the downstream interference layer of the more than one data layer sequence, wherein the interference rejection comprises blind detection of a feedback weight associated with an upstream interference layer sequence, wherein the detection of the feedback weight is based on a residual interference for the data layer sequence being zero, wherein an antenna port sequence of a target data layer sequence for the user equipment is sent to the user equipment in downlink control information via one of a radio resource control configuration or a medium access control element, wherein the interference rejection comprises using the antenna port sequence to determine at least one interfering data layer sequence for use by the user equipment, wherein the at least one demodulation reference signal port is assigned according to a non-linear precoding layer order of the more than one data layer sequence, and there is means for sending by the network node to the user equipment via downlink signaling a one-bit indicator indicating that a data layer sequence port order corresponds to the non-linear precoding layer order, wherein the one-bit indicator is indicating whether a demodulation reference signal port is corresponding to a precancellation order.

In an example aspect of the invention, there is an apparatus, such as a network side apparatus, comprising: at least one processor; and at least one memory including computer program code, where the at least one memory and the computer program code are configured, with the at least one processor, to cause the apparatus to at least: send, by a network node of a communication network, towards a user equipment more than one data layer sequence associated with feedback weights in a transmission from a network node of the communication network, wherein the more than one data layer sequence is ordered for successive precancellation of interference, wherein the more than one data layer sequence is for use by the user equipment to perform interference rejection for communications using the more than one data layer sequence.

A further example embodiment is an apparatus comprising the apparatus of the previous paragraph, wherein at least one antenna port is assigned to each of the more than one data layer sequence, wherein the at least one antenna port comprises at least one demodulation reference signal port, wherein the at least one demodulation reference signal port of a data layer identifies whether the data layer is associated with an upstream interference layer or a downstream interference layer, wherein the interference rejection is performed based on the feedback weights of the upstream interference layer and the downstream interference layer of the more than one data layer sequence, wherein the interference rejection comprises blind detection of a feedback weight associated with an upstream interference layer sequence, wherein the detection of the feedback weight is based on a residual interference for the data layer sequence being zero, wherein an antenna port sequence of a target data layer sequence for the user equipment is sent to the user equipment in downlink control information via one of a radio resource control configuration or a medium access control element, wherein the interference rejection comprises using the antenna port sequence to determine at least one interfering data layer sequence for use by the user equipment, wherein the at least one demodulation reference signal port is assigned according to a non-linear precoding layer order of the more than one data layer sequence, and wherein the at least one memory including the computer program code is configured with the at least one processor to cause the apparatus to: send by the network node to the user equipment via downlink signaling a one-bit indicator indicating that a data layer sequence port order corresponds to the non-linear precoding layer order, wherein the one-bit indicator is indicating whether a demodulation reference signal port is corresponding to a precancellation order.

BRIEF DESCRIPTION OF THE DRAWINGS:

The foregoing and other aspects of embodiments of this invention are made more evident in the following Detailed Description, when read in conjunction with the attached Drawing Figures, wherein:

FIG. 1A shows a diagram of Tomlinson-Harashima Precoding (THP) ;

FIG. 1B shows an example formula for the case of two user equipment and two layers per user equipment in accordance with example embodiments of the invention;

FIG. 2 shows a block diagram of a system in accordance with example embodiments of the invention.

FIG. 3 shows two types of demodulation reference signals for THP;

FIG. 4 shows a signalling and processing diagram of an operation in accordance with example embodiments of the invention;

FIG. 5 shows a simulation setup Table 1;

FIG. 6 shows link level simulation results for line-of-sight (LoS) :

FIG. 7 shows link level simulation results for non-line-of-sight (NLoS) ; and

FIG. 8A and FIG. 8B each show a method in accordance with example embodiments of the invention which may be performed by an apparatus.

DETAILED DESCRIPTION:

In this invention, there is proposed an enhanced network assisted feedback weight detection scheme supporting improved interference measurement at the receiver.

NR standard (Release 15) for MIMO is based on linear precoding. To further boost the throughput of MU-MIMO transmission, Non-linear precoding (NLP) is now being considered as a candidate technique for the later releases of NR. Tomlinson-Harashima Precoding (THP) is the most promising NLP solution which significantly reduces the complexity at the cost of limited modulo loss and power loss.

The main challenge for THP is that its performance with realistic assumptions is still unclear. This invention report aims to enhance the performance of THP under non-ideal channel state information (CSI) . A THP system diagram is shown in FIG. 1A.

In THP, the data layers such as with raw symbols 101 as shown in FIG. 1A are first ordered one by one for successive interference precancellation. The ordering is usually done in a “worst layer first” manner to balance the performance of different layers. In this report it is assumed that the raw symbols layers x= [x ₁; x ₂; ... x _L] are already ordered, where L represents a number of layers.

The successive interference precancellation is done by a feedback filter 110 and modulo device such as the MOD for data 120 as discussed herein and shown in FIG. IA, generating the pre-distorted symbols s= [s ₁; s ₂; ... s _L] . The pre-distorted symbol of layer-i is based on a formula (hereafter referred to as formula F1) :

s _i=MOD (x _i - ∑ _j＜i b _i, j s _j) = x _i - ∑ _j＜i b _i, j s _j + p _i,

where b _i, j is the i-th row and j-th column element of the feedback matrix B, and p _i is the modulo shift. The term b _i, j s _j is expected to cancel the interference from an upstream layer j, j ＜ i at the receiver. To constrain the transmit power a modulo shift is added.

Such as shown in step 140 of FIG. 1A the pre-distorted symbols are precoded by the feedforward filter F= [f ₁, f ₂, ... f _L] to generate the symbols at TX antennas, where

is the feedforward precoding vector for layer-i. The TX symbols are transmitted through the physical channel H= [H ₁; H ₂; ... H _N] , and become the symbols at RX antennas, where

is the physical channel for UE-n, and N is the total number of UEs. M _R and M _T are the number of RX antennas per UE and the number of TX antennas at the base station, respectively.

The RX symbols at RX antennas are combined by the receive filterW, such as with the receive filter W as shown in FIG. 1A, to get the post-combining symbols 160 as shown in FIG IA, where y= [y ₁; y ₂; ... y _L] , where

is a block diagonal matrix including the combining weight vector

for each layer-i. The combining weight vectors in THP are usually designed by the base station, and signalled to the UEs explicitly or implicitly.

Ignoring the noise, such as with the Channel and Interference estimation module 150 as shown in FIG. 1A, the end-to-end transformation from the pre-distorted symbols to the post-combining symbols is y= W*HFs. By replacing s with formula F1 as above, there is the formula (hereafter referred to as formula F2) :

where u (i) is the target UE for layer-i.

The formula below and as in FIG. 1B gives an example for the case of two UEs and two layers per UE.

The first term in formula F2 as shown above is the received desired signal and the modulo shift. The modulo shift will be removed by the modulo device at the receiver. The second term in in formula F2 is the sum of the residual interference from each upstream layer j ＜ i. In the ideal CSI case, the channel H _u (i) is perfectly known at the TX side, and the base station can use a feedback weight

completely eliminate the interference. The third term in in formula F2 is the sum of the residual interference from each downstream layer k ＞ i. In the ideal CSI case, the base station can jointly design the feedforward filter F and the receive filter W to get a lower triangular effective channel H ^eff = WHF, where

So the interference from downstream layers is also eliminated. As a conclusion, the transmission of THP can be made interference free in the ideal CSI case, and the precancellation (feedback) is only needed for the upstream interference layers

A problem exists in that the CSI is mainly non-ideal in the real network due to the delay between CSI measurement and data transmission, the limited resolution of CSI report and the measurement error. It means that the channel known to the base station is different from the channel H for data transmission. So the feedback, feedforward and receive filters designed by the base station cannot fully eliminate the interference.

For linear precoding, the interference cancellation is not only done at the base station but also done at the receiver, since the UE can measure the interference from DMRS, and employ an interference rejection receiver such as the MMSE receiver.

Different from linear precoding, the RX side interference rejection becomes much more difficult with NLP. By decoding the DMRS, the UE is able to know the channel from each RX to each precoded layer. The receiver of layer-i can detect layer-j's DMRS, and get the measured channel

The overall channel measured from DMRS is

By substituting the measured channel to in formula F2, there is the formula, (herein referred to as formula F3) :

It can be seen from the second term of formula F3 as shown above that the channel information is incomplete for the interference from upstream layers, since the receiver only knows the measured channel

and

but not the feedback weight b _i, j. Moreover, the receiver doesn't even know if an interference layer is an upstream layer or a downstream layer, because it doesn't have any information about how the layers are ordered at the base station. Therefore, it is very difficult for the receiver to find a combining weight vector

which mitigates the interference.

Besides the calculation for the combining vectors, the Log-likelihood ratio calculation for demodulation also depends on the interference estimation, and the performance of demodulation may degrade if the estimated interference is inaccurate.

In prior submissions there is focus on designing the receive filter (combining vectors) at the base station. The base station selects the combining vector from a codebook, and explicitly sends the corresponding index to the UE. The receive filter may be designed to be the MRC filter, so the additional signalling is avoided. The UE is supposed to directly use the receive filter which is designed by the base station, so there is no way for the UE to further suppress the interference due to non-ideal CSI.

Other submissions propose another type of DMRS which not only applies the feedforward DMRS but also applies the feedback filter. To distinguish the two types of DMRS, there is defined the regular DMRS which only applies the feedforward DMRS as “feedforward DMRS” , and the DMRS as “full DMRS” . The difference between the feedforward DMRS and the full DMRS is shown in FIG. 3. As shown in FIG. 3 there is full DMRs 310 which is fed back though the Feedback Filter B-1 312 and a Feedforward DMRS 320 to output Feedforward filter F 315.

The channel measured from full DMRS is expected to implicitly include the impact from the feedback filter. However, the interference precancellation process for the full DMRS is still not the same as the data. For example, there is a modulo device for data but not for the DMRS. The modulo device has to be excluded from the DMRS, since the modulo shift is unknown to the UE, but the UE needs to fully know the transmitted symbols to do DMRS based channel estimation.

The full DMRS have two problems due to a lack of modulo shift. First, since there is no modulo device to restrict the power, the transmit power of the DMRS becomes higher than the data. It means that a power back-off has to be applied to the full DMRS in practice. Second, the modulo device used for data at RX only cancels the modulo shift of the target layer, but not the modulo shift of the interference. Such a modulo shift generally makes the interference for data different from the interference measured from the DMRS.

Before describing the example embodiments of the invention in further detail reference is made to FIG. 2. FIG. 2 shows a block diagram of one possible and non-limiting exemplary system in which the example embodiments of the invention may be practiced. In FIG. 2, a mobile station (MS) 110 is in wireless communication with a wireless network 100. The MS 110 or a UE is a wireless or wired, typically mobile device that can access a wireless network. The MS 110 includes one or more processors 120, one or more memories 125, and one or more transceivers 130 interconnected through one or more buses 127. Each of the one or more transceivers 130 includes a receiver Rx, 132 and a transmitter Tx 133. The one or more buses 127 may be address, data, or control buses, and may include any interconnection mechanism, such as a series of lines on a motherboard or integrated circuit, fiber optics or other optical communication equipment, and the like. The one or more transceivers 130 are connected to one or more antennas 128. The one or more memories 125 include computer program code 123. The MS 110 may include a precoding processing unit (PPu) module 140 e.g., a precoding processor unit (PPu) for UE, such as the MS 110, which is configured to perform at least the precoding related signal detection and processing of the example embodiments of the invention as described herein. It is noted that the use of the PPU is optional, and the example embodiments of the invention may be performed with or by another module or processor, such as the processor (s) 120. The PPu module 140 comprising one of or both parts 140-1 and/or 140-2, which may be implemented in a number of ways. The PPu module 140 may be implemented in hardware as PPu module 140-1, such as being implemented as part of the one or more processors 120. The PPu module 140-1 may be implemented also as an integrated circuit or through other hardware such as a programmable gate array. In another example, the PPu module 140 may be implemented as PPu module 140-2, which is implemented as computer program code 123 and is executed by the one or more processors 120. For instance, the one or more memories 125 and the computer program code 123 may be configured, with the one or more processors 120, to cause the user equipment 110 to perform one or more of the precoding related operations as described herein. The MS 110 communicates with gNB 170 via a wireless link 111. Further, it is noted that the labeling of the MS 110 as in FIG. 2 is non-limiting and operations of the MS 110 may similarly be performed by a device labeled as a user equipment or UE, or a user equipment or UE device or a network device, a mobile device (MS) , a, wireless device and/or IoT device.

The gNB 170 (NR/5G Node B or possibly an evolved NB) is a base station (e.g., for LTE, long term evolution, GSM, and other communications technologies including legacy communications technologies) that provides access by wireless devices such as the MS 110 to the wireless network 100. The gNB 170 includes one or more processors 152, one or more memories 155, one or more network interfaces (N/W I/F (s) ) 161, and one or more transceivers 160 interconnected through one or more buses 157. Each of the one or more transceivers 160 includes a receiver Rx 162 and a transmitter Tx 163. The one or more transceivers 160 are connected to one or more antennas 158. The one or more memories 155 include computer program code 153. The gNB 170 includes a precoding processor unit module for gNB (PPu module 150) which is configured to perform at least the precoding related signaling and processing in accordance with the example embodiments of the invention as described herein. It is again noted that a use of the PPU is optional, and the example embodiments of the invention may be performed with or by another module or processor, such as the processor (s) 120. The PPu module 150 comprising one of or both parts PPu module 150-1 and/or PPu module 150-2, which may be implemented in a number of ways. The PPu module 150 may be implemented in hardware as PPu module 150-1, such as being implemented as part of the one or more processors 152. The PPu module 150-1 may be implemented also as an integrated circuit or through other hardware such as a programmable gate array.

In another example, the PPu module 150 may be implemented as PPu module 150-2, which is implemented as computer program code 153 and is executed by the one or more processors 152. For instance, the one or more memories 155 and the computer program code 153 are configured to cause, with the one or more processors 152, the gNB 170 to perform one or more of at least the precoding related signaling and processing operations as described herein. The one or more network interfaces 161 communicate over a network such as via the

links

176 and 131. Two or more gNB 170 may communicate using, e.g., link 176. The link 176 may be wired or wireless or both and may implement, e.g., an X2 interface.

The one or more buses 157 may be address, data, or control buses, and may include any interconnection mechanism, such as a series of lines on a motherboard or integrated circuit, fiber optics or other optical communication equipment, wireless channels, and the like. For example, the one or more transceivers 160 may be implemented as a remote radio head (RRH) 195, with the other elements of the gNB 170 being physically in a different location from the RRH. The RRH can be part of a base transceiver station (BTS) communicating with devices including the gNB 170 as in FIG. 2. The RRH can have one or more buses 157 that could be implemented in part as fiber optic cable to connect the other elements of the gNB 170 to the remote radio head (RRH) 195.

It is noted that description herein indicates that “cells” perform functions, but it should be clear that the gNB that forms the cell can perform the functions. The cell makes up part of a gNB or eNB. That is, there can be multiple cells per gNB or eNB.

The wireless network 100 may include a base station controller (BSC) 190 that can include precoding control functionality, and which provides connectivity with a further network, such as a telephone network and/or a data communications network (e.g., the Internet) . The gNB 170 is coupled via a link 131 to the BSC 190. The link 131 may be implemented as, e.g., an S1 interface. The BSC 190 includes one or more processors 175, one or more memories 171, and one or more network interfaces (N/W I/F (s) ) 180, interconnected through one or more buses 185. The one or more memories 171 include computer program code 173. The one or more memories 171 and the computer program code 173 are configured to, with the one or more processors 175, cause the BSC 190 to perform one or more operations.

The wireless network 100 may implement network virtualization, which is the process of combining hardware and software network resources and network functionality into a single, software-based administrative entity, a virtual network. Network virtualization involves platform virtualization, often combined with resource virtualization. Network virtualization is categorized as either external, combining many networks, or parts of networks, into a virtual unit, or internal, providing network-like functionality to software containers on a single system. Note that the virtualized entities that result from the network virtualization are still implemented, at some level, using hardware such as

processors

152 or 175 and

memories

155 and 171, and also such virtualized entities create technical effects.

The computer

readable memories

125, 155, and 171 may be of any type suitable to the local technical enviromnent and may be implemented using any suitable data storage technology, such as semiconductor based memory devices, flash memory, magnetic memory devices and systems, optical memory devices and systems, fixed memory and removable memory. The computer

readable memories

125, 155, and 171 may be means for performing storage functions. The

processors

120, 152, and 175 may be of any type suitable to the local technical enviromnent, and may include one or more of general purpose computers, special purpose computers, microprocessors, digital signal processors (DSPs) and processors based on a multi-core processor architecture, as non-limiting examples. The

processors

120, 152, and 175 may be means for performing functions, such as controlling the MS 110, gNB 170, and other functions as described herein.

It is noted that any reference to terms used in this specification or labels in any figure (FIG. ) which may be associated with a particular communication technology are not limiting (e.g., gNB or an eNB or an access node) . The Example embodiments of the invention as described herein can be performed using devices operating in GSM/EDGE, LTE, and/or 5G, as well as any devices e.g., gNB, eNB, BTS, BSC, UE, and/or MS operating in any other communication technologies. Further, FIG. 2 can be used for operations in accordance with example embodiments of the invention, between such devices as for example MS-BTS-BSC for GSM; UE-gNB for 5G; and UE-eNB for LTE. It is noted that this example is non-limiting and the operations in accordance with the example embodiments of the invention may performed using different devices and/or different than the example.

In general, the various embodiments of the mobile station 110 can include, but are not limited to, cellular telephones such as smart phones, tablets, personal digital assistants (PDAs) having wireless communication capabilities, portable computers having wireless communication capabilities, image capture devices such as digital cameras having wireless communication capabilities, gaming devices having wireless communication capabilities, music storage and playback appliances having wireless communication capabilities, and/or Internet appliances permitting wireless Internet access and browsing with wireless communication capabilities, as well as portable units or terminals that incorporate combinations of such functions.

Embodiments herein may be implemented in software (executed by one or more processors) , hardware (e.g., an application specific integrated circuit) , or a combination of software and hardware. In an example of an embodiment, the software (e.g., application logic, an instruction set) is maintained on any one of various conventional computer-readable media. In the context of this document, a “computer-readable medium” may be any media or means that can contain, store, communicate, propagate or transport the instructions for use by or in connection with an instruction execution system, apparatus, or device, such as a computer, with one example of a computer described and depicted, e.g., in FIG. 2. A computer-readable medium may comprise a computer-readable storage medium or other device that may be any media or means that can contain or store the instructions for use by or in connection with an instruction execution system, apparatus, or device, such as a computer.

In accordance with example embodiments of this invention it can be assumed that the feedforward DMRS is used, and there is explicit signalling or implicit agreement about the base station designed receive filter. Different from the prior art, example embodiments of the invention enable the UE to further adjust the receive filter for improved interference rejection. The base station designed receive filter just gives the information about what receiver is assumed at the TX side, but it is not necessarily the final receive filter at the RX side as in accordance with embodiments of the invention.

Example embodiments of the invention provide that the base station shall assist the UE to distinguish an upstream interference layer from a downstream interference layer. This can be implicitly done by assigning the DMRS ports according to the layer order, e.g., DMRS port-i shall be assigned to the i-th layer. Since the DMRS port index for the target layer is signalled in the downlink control information (DCI) , the receiver of layer-iwill know that layers 1, 2, ... i -1 are its upstream layers.

For each upstream layer interference, the receiver shall blindly detect the feedback weight based on the assumption that the residual interference is 0 after applying the base station designed receive filter. The upstream interference is then modified according to the feedback weight. In contrast, the downstream interference is measured without the detection of the feedback weight.

The receiver shall combine the upstream and downstream interference as the final estimated interference, and derive the interference rejection receive filter. Though the residual upstream interference is supposed to be 0 with the base station designed receive filter, the UE may finally select a different receive filter which suppresses the downstream interference but leaves the residual upstream interference non-zero, and achieves a better trade-off.

More generally, the UE shall do blind detection only for the interference layers which are precancelled, and do explicit detection for the rest of the layers. Not all the upstream layers need to be precancelled in some cases. For example, the feedforward and receive filter as has been designed ensure that the intra-UE interference is already 0 before interference precancellation, so there is no precancellation for intra-UE interference, i.e., b _i, j = 0 when u (i) = u (j) . In this case, blind detection is not needed for an interference layer j when u (i) = u (j) , even if j is an upstream layer of the target layer i.

The proposed signalling and processing diagram can be found in FIG. 4. As shown in FIG. 4 there is the gNB 170 sending information 410 towards the UE 110. The information 410 including RX filter information and a Layer order correspondence indicator. Further, as shown in FIG. 4 the gNB 170 is sending towards the UE 110 information 420 which includes a Feedforward DMRS and Data. With this information the UE 110 can derive information 430 as shown in FIG. 4. Information 430 including Channel estimation for the target signal, a derived gNB designed RX filter, Channel estimation for the interference layers, Blind detection of feedback weights, Calculate the interference with the blindly detected feedback weights, and derive the interference rejection RX filter. Certain new components introduced in accordance with some example embodiments of the invention are marked in bold in the information 430 as shown in FIG. 4.

First, the gNB shall send the information about the base station designed RX filter

Filter

is used at the TX side to calculate the feedback weight

This signalling is not new, rather it is necessary for all feedforward DMRS based THP solutions. From this point it can be assumed that the base station designed RX filter is the MRC receiver, and this assumption is sent to the UE as the RX filter information. It can also be assumed that the precancellation is avoided for the intra-UE interference.

Second, the gNB shall send a one bit layer order correspondence indicator which indicates if the DMRS port is corresponding to the precancellation order of THP. The layer order correspondence indicator can be sent via any downlink signalling, e.g., RRC configuration, MAC CE or DCI. RRC configuration is assumed in the following discussion. As an alternative to the layer order correspondence indicator, the base station can also explicitly send the DMRS port indices of all precancelled layers to the target layer, but the overhead will be increased.

It can be assumed that in in accordance with embodiments as described herein the layer correspondence is enabled, and focus on the receiving process of one layer i in the following analysis.

For layer i, its target UE shall first estimate the channel of the desired signal

from DMRS port i. It shall also derive the base station designed RX filter

which is the MRC combiner.

FIG. 5 shows Table I. Simulation Setup. FIG. 5 shows Parameters and Configuration for a simulation setup using example embodiments of the invention.

For each non-intra-UE upstream layer j, j ＜ i and u (j) ≠ u (i) , the interference channel

shall be estimated from DMRS port j. The receiver knows that layer j has been precancelled by a feedback weight b _i, j at the TX side, but it doesn't know the value of b _i, j. According to formula F3 and the assumption that the residual interference is 0 when the base station designed receiver

is used, the blind detection of the feedback weight shall be done based on

i.e.,

where

is the estimation of the feedback weight b _i, j. After deriving the estimated feedback weight, the blindly detected interference channel after precancellation is calculated as

For each intra-UE interference layer or downstream layer k, u (k) = u (i) or k ＞ i, the interference channel

shall be estimated from DMRS port k. There is no precancellation for layer k, so blind detection is not needed.

Finally, the interference covariance matrix for the target layer i is calculated using a formula (herein referred to as F4) as:

, (4) , where

is the covariance matrix of inter-cell interference and noise (non-MU-MIMO interference and noise) , which can be estimated in the same way as the linear precoding case. The MMSE receiver for layer i is calculated as

is used as the final receive filter instead of the base station designed receive filter

In general, w _i will be close to

when the first term is dominant in formula F4, since the interference corresponding to the first term is assumed to be fully removed by using

as the receive filter. Otherwise w _i can be very different from

More specifically, the final receive weight is usually closer to the base station designed receiver when the target layer i is a bottom layer, and substantially differs from the base station designed receiver when i is a top layer.

For the 1 ^st layer (i = 1) , there is no precancelled interference and thus no blind detection. All the interference can be explicitly detected, and the interference rejection capability is the same as the linear precoding case. For the other layers, the interference rejection is still less effective than the linear case since the blindly detected feedback weight is not necessarily accurate. In any case, the interference rejection capability is at least partially enabled for those layers with explicitly detected interference.

As an alternative to the above process, it is also possible to skip the per-layer detection of the downstream layers. Instead, the UE can subtract the detected DMRS of the target layer, the intra-UE interference layer and the upstream layers from the received signa and treat the rest of the signal as the total interference from downstream layers, other cells and noise.

As shown in FIG. 6 and FIG. 7 there is compared four THP DMRS and receiver schemes in a link level simulation, including:

1) the baseline scheme of feedforward DMRS and MRC receiver;

2) full DMRS and MMSE receiver, with an ideal assumption that there is no power restriction for the DMRS;

3) feedforward DMRS and MMSE receiver with blind detection of the feedback weights, which is the proposed solution in this invention; and

4) the ideal case of feedforward DMRS and MMSE receiver with ideal knowledge of the feedback weights, which is unrealistic in practice.

The four schemes as compared use a same transmission method at the base station a previously deigned, including a same feedforward filter, feedback filter, and transmitted data.

FIG. 6 and FIG. 7 show simulation results in accordance with example embodiments of the invention for line-of-sight (LoS) and non-line-of-sight (NLoS) channel models.

As shown in FIG. 6 there is shown a graph identifying for line-of-sight (LoS) a signal to noise ratio (SNR) based on a Sum Spectrum Efficiency. As shown in FIG. 6 there is a FeedForwardDMRS_MRC 630, a FullDMRS_MMSE 640, a FeedForwardDMRS_blindFeedbackDetect_MMSE 620, and a FeedForwardDMRS_IdealFeedbackDetect_MMSE 610.

As shown in FIG. 7 there is shown a graph identifying for non-line-of-sight (NLoS) a signal to noise ratio (SNR) based on a Sum Spectrum Efficiency. As shown in FIG. 6 there is a FeedForwardDMRS_MRC 740, a FullDMRS_MMSE 730, a FeedForwardDMRS_blindFeedbackDetect_MMSE 720, and a FeedForwardDMRS_IdealFeedbackDetect_MMSE 710.

It can be seen from FIG. 6 and FIG. 7 that although the proposed scheme (feedforward DMRS with blind detection) may still not be as good as the ideal case, it is always better than the two existing solutions. The gain over the baseline scheme comes from the accurate explicit detection of the downstream and intra-UE interference, and the best-effort blind detection for the precancelled interference. The gain over the full DMRS scheme comes from the fact that the interference measured with full DMRS is inaccurate due to the lack of modulo in DMRS.

The performance difference among the four schemes is relatively small in FIG. 6. The LoS channel is stable, so the CSI is close to ideal, and the gain from interference rejection is limited. In contrast, the interference rejection gain is significant with the NLoS channel.

In conclusion, the proposed network assisted feedback weight detection scheme improves the throughput by supporting improved interference measurement at the receiver. The overhead is as low as one bit for the layer order correspondence indicator in the RRC configuration.

Figure 8A illustrates operations, such as a method, which may be performed by a network device such as, but not limited to a mobile station or user equipment, such as the MS 110 as in FIG. 2. As shown in step 810 of FIG. 8A there is identifying, by a user equipment of a communication network, more than one data layer sequence associated with feedback weights in a transmission from a network node of the communication network, wherein the more than one data layer sequence is ordered for successive precancellation of interference. Then as shown in step 820 of FIG. 8B there is performing, by the user equipment, interference rejection for communications using the more than one data layer sequence.

In accordance with the example aspects of the invention as stated in the paragraph above, wherein at least one antenna port is assigned to each of the more than one data layer sequence, wherein the at least one antenna port comprises at least one demodulation reference signal port.

In accordance with the example aspects of the invention as stated in the paragraphs above, wherein the at least one demodulation reference signal port of a data layer identifies whether the data layer is associated with an upstream interference layer or a downstream interference layer.

In accordance with the example aspects of the invention as stated in the paragraphs above, wherein the interference rejection is performed based on the feedback weights of the upstream interference layer and the downstream interference layer of the more than one data layer sequence.

In accordance with the example aspects of the invention as stated in the paragraphs above, there is: blindly detecting a feedback weight associated with an upstream interference layer sequence.

In accordance with the example aspects of the invention as stated in the paragraphs above, wherein the detecting the feedback weight is based on a residual interference for the data layer sequence being zero.

In accordance with the example aspects of the invention as stated in the paragraphs above, wherein an antenna port sequence of a target data layer sequence for the user equipment is received by the user equipment in downlink control information via one of a radio resource control configuration or a medium access control element.

In accordance with the example aspects of the invention as stated in the paragraphs above, the interference rejection comprises using the antenna port sequence to determine at least one interfering data layer sequence for use by the user equipment in upstream communication.

In accordance with the example aspects of the invention as stated in the paragraphs above, wherein the at least one demodulation reference signal port is assigned according to a non-linear precoding layer order of the more than one data layer sequence.

In accordance with the example aspects of the invention as stated in the paragraphs above, there is receiving from the network node via downlink signaling a one-bit indicator indicating that a data layer sequence port order corresponds to the non-linear precoding layer order.

In accordance with the example aspects of the invention as stated in the paragraphs above, wherein the one-bit indicator is indicating whether a demodulation reference signal port is corresponding to a precancellation order.

A non-transitory computer-readable medium (Memory (ies) 125 as in FIG. 2) storing program code (Computer Program Code 123 as in FIG. 2) , the program code executed by at least one processor (Processor (s) 120 and/or PPu Module 140-1, Computer Program Code 123, as in FIG. 2) to perform the operations as at least described in the paragraphs above.

In accordance with an example embodiment of the invention as described above there is an apparatus comprising: means for identifying (Memory (ies) 125, Computer Program Code 123, and/or PPU Module 140-2, Processor (s) 120 and/or PPu Module 140-1 as in FIG. 2) , by a user equipment (MS 110 as in FIG. 2) of a communication network (wireless network 100 as in FIG. 2) , more than one data layer sequence associated with feedback weights in a transmission from a network node (gNB 170 as in FIG. 2) of the communication network (wireless network 100 as in FIG. 2) , wherein the more than one data layer sequence is ordered for successive precancellation of interference. Then there are means for performing (Memory (ies) 125, Computer Program Code 123, and/or PPU Module 140-2, Processor (s) 120 and/or PPu Module 140-1 as in FIG. 2) , by the user equipment (MS 110 as in FIG. 2) , interference rejection for communications using the more than one data layer sequence.

In the example aspect of the invention according to the paragraph above, wherein at least the means for identifying and performing comprises a non-transitory computer readable medium [Memory (ies) 125 as in FIG. 2] encoded with a computer program [Computer Program Code 123 and/or PPU Module 140-2 as in FIG. 2] executable by at least one processor [Processor (s) 120 and/or PPu Module 140-1, Computer Program Code 123, as in FIG. 2] .

Figure 8B illustrates operations, such as a method, which may be performed by a network device such as, but not limited to a network node, such as the gNB 170 as in FIG. 2 or a base station. As shown in step 850 of FIG. 8b there is sending, by a network node of a communication network, towards a user equipment more than one data layer sequence associated with feedback weights in a transmission from a network node of the communication network. As shown in step 860 as in FIG 8B wherein the more than one data layer sequence is ordered for successive precancellation of interference. Then as shown in step 870 as in FIG. 8B wherein the more than one data layer sequence is for use by the user equipment to perform interference rejection for communications using the more than one data layer sequence.

In accordance with the example aspects of the invention as stated in the paragraphs above, wherein the interference rejection comprises blind detection of a feedback weight associated with an upstream interference layer sequence.

In accordance with the example aspects of the invention as stated in the paragraphs above, wherein the detection of the feedback weight is based on a residual interference for the data layer sequence being zero.

In accordance with the example aspects of the invention as stated in the paragraphs above, wherein an antenna port sequence of a target data layer sequence for the user equipment is sent to the user equipment in downlink control information via one of a radio resource control configuration or a medium access control element.

In accordance with the example aspects of the invention as stated in the paragraphs above, wherein the interference rejection comprises using the antenna port sequence to determine at least one interfering data layer sequence for use by the user equipment.

In accordance with the example aspects of the invention as stated in the paragraphs above, comprising: sending by the network node to the user equipment via downlink signaling a one-bit indicator indicating that a data layer sequence port order corresponds to the non-linear precoding layer order.

A non-transitory computer-readable medium (Memory (ies) 155 as in FIG. 2) storing program code (Computer Program Code 153 as in FIG. 2) , the program code executed by at least one processor (Processor (s) 152 and/or PPu Module 150-1, Computer Program Code 153 and/or PPU Module 150-2 as in FIG. 2) to perform the operations as at least described in the paragraphs above.

In accordance with an example embodiment of the invention as described above there is an apparatus comprising: means for sending (Memory (ies) 155, Computer Program Code 153, and/or PPU Module 150-2, Processor (s) 152 and/or PPu Module 150-1 as in FIG. 2) , by a network node of a communication network (wireless network 100 as in FIG. 2) , towards a user equipment (MS 110 as in FIG. 2) more than one data layer sequence associated with feedback weights in a transmission from a network node of the communication network. There is means for the more than one data layer sequence to be ordered (Memory (ies) 155, Computer Program Code 153, and/or PPU Module 150-2, Processor (s) 152 and/or PPu Module 150-1 as in FIG. 2) for successive precancellation of interference. There is means for the more than one data layer sequence is for use by the user equipment to perform (Memory (ies) 155, Computer Program Code 153, and/or PPU Module 150-2, Processor (s) 152 and/or PPu Module 150-1 as in FIG. 2) interference rejection for communications using the more than one data layer sequence.

In the example aspect of the invention according to the paragraph above, wherein at least the means for sending, ordering, and performing comprises a non-transitory computer readable medium [Memory (ies) 155 as in FIG. 2] encoded with a computer program [Computer Program Code 153 and/or PPU Module 150-2 as in FIG. 2] executable by at least one processor [Processor (s) 152 and/or PPu Module 150-1 as in FIG. 2] .

In general, the various embodiments may be implemented in hardware or special purpose circuits, software, logic or any combination thereof. For example, some aspects may be implemented in hardware, while other aspects may be implemented in firmware or software which may be executed by a controller, microprocessor or other computing device, although the invention is not limited thereto. While various aspects of the invention may be illustrated and described as block diagrams, flow charts, or using some other pictorial representation, it is well understood that these blocks, apparatus, systems, techniques or methods described herein may be implemented in, as non-limiting examples, hardware, software, firmware, special purpose circuits or logic, general purpose hardware or controller or other computing devices, or some combination thereof.

Embodiments of the inventions may be practiced in various components such as integrated circuit modules. The design of integrated circuits is by and large a highly automated process. Complex and powerful software tools are available for converting a logic level design into a semiconductor circuit design ready to be etched and formed on a semiconductor substrate.

The word "exemplary" is used herein to mean "serving as an example, instance, or illustration. " Any embodiment described herein as "exemplary" is not necessarily to be construed as preferred or advantageous over other embodiments. All of the embodiments described in this Detailed Description are exemplary embodiments provided to enable persons skilled in the art to make or use the invention and not to limit the scope of the invention which is defined by the claims.

The foregoing description has provided by way of exemplary and non-limiting examples a full and informative description of the best method and apparatus presently contemplated by the inventors for carrying out the invention. However, various modifications and adaptations may become apparent to those skilled in the relevant arts in view of the foregoing description, when read in conjunction with the accompanying drawings and the appended claims. However, all such and similar modifications of the teachings of this invention will still fall within the scope of this invention.

It should be noted that the terms "connected, " "coupled, " or any variant thereof, mean any connection or coupling, either direct or indirect, between two or more elements, and may encompass the presence of one or more intermediate elements between two elements that are "connected" or "coupled" together. The coupling or connection between the elements can be physical, logical, or a combination thereof. As employed herein two elements may be considered to be "connected" or "coupled" together by the use of one or more wires, cables and/or printed electrical connections, as well as by the use of electromagnetic energy, such as electromagnetic energy having wavelengths in the radio frequency region, the microwave region and the optical (both visible and invisible) region, as several non-limiting and non-exhaustive examples.

Furthermore, some of the features of the preferred embodiments of this invention could be used to advantage without the corresponding use of other features. As such, the foregoing description should be considered as merely illustrative of the principles of the invention, and not in limitation thereof.

Claims

A method, comprising:

identifying, by a user equipment of a communication network, more than one data layer sequence associated with feedback weights in a transmission from a network node of the communication network, wherein the more than one data layer sequence is ordered for successive precancellation of interference; and

performing, by the user equipment, interference rejection for communications using the more than one data layer sequence.
The method according to claim 1, wherein at least one antenna port is assigned to each of the more than one data layer sequence, wherein the at least one antenna port comprises at least one demodulation reference signal port.
The method according to claim 2, wherein the at least one demodulation reference signal port of a data layer identifies whether the data layer is associated with an upstream interference layer or a downstream interference layer.
The method according to claim 3, wherein the interference rejection is performed based on the feedback weights of the upstream interference layer and the downstream interference layer of the more than one data layer sequence.
The method according to claim 3, comprising:

blindly detecting a feedback weight associated with an upstream interference layer sequence.
The method according to claim 5, wherein the detecting the feedback weight is based on a residual interference for the data layer sequence being zero.
The method according to claim 3, wherein an antenna port sequence of a target data layer sequence for the user equipment is received by the user equipment in downlink control information via one of a radio resource control configuration or a medium access control element.
The method according to claim 7, the interference rejection comprises using the antenna port sequence to determine at least one interfering data layer sequence for use by the user equipment in upstream communication.
The method according to claim 2, wherein the at least one demodulation reference signal port is assigned according to a non-linear precoding layer order of the more than one data layer sequence.
The method according to claim 9, comprising: receiving from the network node via downlink signaling a one-bit indicator indicating that a data layer sequence port order corresponds to the non-linear precoding layer order.
The method of claim 10, wherein the one-bit indicator is indicating whether a demodulation reference signal port is corresponding to a precancellation order.
An apparatus, comprising:

means for identifying, by a user equipment of a communication network, more than one data layer sequence associated with feedback weights in a transmission from a network node of the communication network, wherein the more than one data layer sequence is ordered for successive precancellation of interference; and

means for performing, by the user equipment, interference rejection for communications using the more than one data layer sequence.
The apparatus according to claim 12, wherein at least one antenna port is assigned to each of the more than one data layer sequence, wherein the at least one antenna port comprises at least one demodulation reference signal port.
The apparatus according to claim 13, wherein the at least one demodulation reference signal port of a data layer identifies whether the data layer is associated with an upstream interference layer or a downstream interference layer.
The apparatus according to claim 14, wherein the interference rejection is performed based on the feedback weights of the upstream interference layer and the downstream interference layer of the more than one data layer sequence.
The apparatus according to claim 14, comprising:

blindly detecting a feedback weight associated with an upstream interference layer sequence.
The apparatus according to claim 16, wherein the detecting the feedback weight is based on a residual interference for the data layer sequence being zero.
The apparatus according to claim 14, wherein an antenna port sequence of a target data layer sequence for the user equipment is received by the user equipment in downlink control information via one of a radio resource control configuration or a medium access control element.
The apparatus according to claim 18, the interference rejection comprises using the antenna port sequence to determine at least one interfering data layer sequence for use by the user equipment in upstream communication.
The apparatus according to claim 13, wherein the at least one demodulation reference signal port is assigned according to a non-linear precoding layer order of the more than one data layer sequence.
The apparatus according to claim 19, comprising: receiving from the network node via downlink signaling a one-bit indicator indicating that a data layer sequence port order corresponds to the non-linear precoding layer order.
The apparatus of claim 21, wherein the one-bit indicator is indicating whether a demodulation reference signal port is corresponding to a precancellation order.
A method, comprising:

sending, by a network node of a communication network, towards a user equipment more than one data layer sequence associated with feedback weights in a transmission from a network node of the communication network, wherein the more than one data layer sequence is ordered for successive precancellation of interference, wherein the more than one data layer sequence is for use by the user equipment to perform interference rejection for communications using the more than one data layer sequence.
The method according to claim 23, wherein at least one antenna port is assigned to each of the more than one data layer sequence, wherein the at least one antenna port comprises at least one demodulation reference signal port.
The method according to claim 24, wherein the at least one demodulation reference signal port of a data layer identifies whether the data layer is associated with an upstream interference layer or a downstream interference layer.
The method according to claim 25, wherein the interference rejection is performed based on the feedback weights of the upstream interference layer and the downstream interference layer of the more than one data layer sequence.
The method according to claim 25, wherein the interference rejection comprises blind detection of a feedback weight associated with an upstream interference layer sequence.
The method according to claim 27, wherein the detection of the feedback weight is based on a residual interference for the data layer sequence being zero.
The method according to claim 25, wherein an antenna port sequence of a target data layer sequence for the user equipment is sent to the user equipment in downlink control information via one of a radio resource control configuration or a medium access control element.
The method according to claim 28, wherein the interference rejection comprises using the antenna port sequence to determine at least one interfering data layer sequence for use by the user equipment.
The method according to claim 24, wherein the at least one demodulation reference signal port is assigned according to a non-linear precoding layer order of the more than one data layer sequence.
The method according to claim 31, comprising: sending by the network node to the user equipment via downlink signaling a one-bit indicator indicating that a data layer sequence port order corresponds to the non-linear precoding layer order.
The method of claim 32, wherein the one-bit indicator is indicating whether a demodulation reference signal port is corresponding to a precancellation order.
An apparatus, comprising:

means for sending, by a network node of a communication network, towards a user equipment more than one data layer sequence associated with feedback weights in a transmission from a network node of the communication network, wherein the more than one data layer sequence is ordered for successive precancellation of interference, wherein the more than one data layer sequence is for use by the user equipment to perform interference rejection for communications using the more than one data layer sequence.
The apparatus according to claim 34, wherein at least one antenna port is assigned to each of the more than one data layer sequence, wherein the at least one antenna port comprises at least one demodulation reference signal port.
The apparatus according to claim 35, wherein the at least one demodulation reference signal port of a data layer identifies whether the data layer is associated with an upstream interference layer or a downstream interference layer.
The apparatus according to claim 36, wherein the interference rejection is performed based on the feedback weights of the upstream interference layer and the downstream interference layer of the more than one data layer sequence.
The apparatus according to claim 36, wherein the interference rejection comprises

blind detection of a feedback weight associated with an upstream interference layer sequence.
The apparatus according to claim 38, wherein the detection of the feedback weight is based on a residual interference for the data layer sequence being zero.
The apparatus according to claim 34, wherein an antenna port sequence of a target data layer sequence for the user equipment is sent to the user equipment in downlink control information via one of a radio resource control configuration or a medium access control element.
The apparatus according to claim 39, wherein the interference rejection comprises using the antenna port sequence to determine at least one interfering data layer sequence for use by the user equipment.
The apparatus according to claim 35, wherein the at least one demodulation reference signal port is assigned according to a non-linear precoding layer order of the more than one data layer sequence.
The apparatus according to claim 42, comprising: means for sending by the network node to the user equipment via downlink signaling a one-bit indicator indicating that a data layer sequence port order corresponds to the non-linear precoding layer order.
The apparatus according to claim 43, wherein the one-bit indicator is indicating whether a demodulation reference signal port is corresponding to a precancellation order.