CN112771786B

CN112771786B - Network-assisted feedback weight detection for nonlinear precoding

Info

Publication number: CN112771786B
Application number: CN201880097793.XA
Authority: CN
Inventors: 邵叙宁; E·维索特斯基; F·福克; 齐天阳
Original assignee: Nokia Shanghai Bell Co Ltd; Nokia Solutions and Networks Oy
Current assignee: Nokia Shanghai Bell Co Ltd; Nokia Solutions and Networks Oy
Priority date: 2018-09-19
Filing date: 2018-09-19
Publication date: 2023-12-08
Anticipated expiration: 2038-09-19
Also published as: CN112771786A; WO2020056650A1

Abstract

According to example embodiments of the invention described herein, there is at least one 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 transmissions from a network node of the communication network, wherein the more than one data layer sequence is ordered for successive interference pre-cancellation; and performing interference suppression by the user equipment for communications using more than one data layer sequence. In addition, sending, by a network node of the communication network, more than one data layer sequence towards the user equipment, the more than one data layer sequence being associated with feedback weights in transmissions from the network node of the communication network, wherein the more than one data layer sequence is ordered for successive interference pre-cancellation, wherein the more than one data layer sequence is used by the user equipment to perform interference suppression for communications using the more than one data layer sequence.

Description

Network-assisted feedback weight detection for nonlinear precoding

Technical Field

The teachings according to the exemplary embodiments of this invention relate generally to enhanced network assisted feedback weight detection schemes and, more particularly, to enhanced network assisted feedback weight detection schemes that support improved interference measurement at a receiver.

Background

This section is intended to provide a background or context to the application 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 of the present application and is not admitted to be prior art by inclusion in this section.

Some abbreviations that may be found in the specification and/or drawings are defined as follows:

NR new radio

NLP nonlinear precoding

MU multi-user

MIMO multiple input multiple output

THP Tomlinson-Harashima precoding

TX transmission

RX reception

UE user equipment

DMRS demodulation reference signal

MRC maximum ratio combining

MMSE minimum mean square error

LLR log-likelihood ratio

CSI channel state information

DCI downlink control information

LoS visual distance

NLoS non-line-of-sight

In multi-antenna techniques, precoding is used to map modulation symbols onto different antennas. The type of precoding depends on the multi-antenna technique used and the number of layers and antenna ports. The purpose of utilizing precoding is to achieve optimal data reception at the receiver.

Note that the transmission or signaling will be affected by various types of interference and fading, which can also be seen as some type of coding caused by the radio channel. To address this problem, known reference signals may be transmitted with the data and used by the receiver to reduce or eliminate interference for signaling and/or demodulation.

Example embodiments of the present invention are directed towards enhancing such signaling for addressing such interference.

Disclosure of Invention

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 transmissions from a network node of the communication network, wherein the more than one data layer sequence is ordered for successive interference pre-cancellation; and performing interference suppression by the user equipment for communications using more than one data layer sequence.

Another example embodiment is a method comprising the above paragraph, wherein at least one antenna port is assigned to each of the more than one data layer sequences, 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 the data layer identifies whether the data layer is associated with an upstream or downstream interference layer, wherein interference suppression is performed based on feedback weights of the upstream and downstream interference layers of the more than one data layer sequences, there is blind detection of feedback weights associated with the upstream interference layer sequences, wherein the detection feedback weights are zero based on residual interference for the data layer sequences, wherein the antenna port sequence of the 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 medium access control element, wherein interference suppression comprises determining at least one interference data layer sequence for use by a user equipment in upstream communication using an antenna port sequence, wherein at least one demodulation reference signal port is assigned according to a non-linear precoding layer order of more than one data layer sequence, there is a one bit indicator received from a network node via downlink signaling indicating that the data layer sequence port order corresponds to the non-linear precoding layer order, and wherein the one bit indicator indicates whether the demodulation reference signal port corresponds to a pre-cancellation 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 transmissions from a network node of the communication network, wherein the more than one data layer sequence is ordered for successive interference pre-cancellation; and means for performing interference suppression by the user equipment for communications using more than one data layer sequence.

Another example embodiment is an apparatus comprising the apparatus of the preceding paragraph, wherein at least one antenna port is assigned to each of the more than one data layer sequences, 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 the data layer identifies whether the data layer is associated with an upstream or a downstream interference layer, wherein interference suppression is performed based on feedback weights of the upstream and downstream interference layers of the more than one data layer sequences, there is means for blindly detecting the feedback weights associated with the upstream interference layer sequences, wherein the detection feedback weights are zero based on residual interference for the data layer sequences, wherein the antenna port sequence for the target data layer sequence of the user equipment is received by the user equipment in downlink control information via one of: a radio resource control configuration or medium access control element, wherein interference suppression comprises determining at least one interference data layer sequence for use by a user equipment in upstream communication using an antenna port sequence, wherein at least one demodulation reference signal port is assigned according to a non-linear precoding layer order of more than one data layer sequence, there is means for receiving from a network node via downlink signaling a one bit indicator indicating that the data layer sequence port order corresponds to the non-linear precoding layer order, and wherein the one bit indicator indicates whether the demodulation reference signal port corresponds to a pre-cancellation 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, wherein the at least one memory and the computer program code are configured to, with the at least one processor, cause the apparatus at least to: identifying, by a user equipment of a communication network, more than one data layer sequence associated with feedback weights in transmissions from a network node of the communication network, wherein the more than one data layer sequence is ordered for successive interference pre-cancellation; and performing interference suppression by the user equipment for communications using more than one data layer sequence.

Another example embodiment is an apparatus comprising the above paragraph, wherein at least one antenna port is assigned to each of the more than one sequence of data layers, 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 or a downstream interference layer, wherein interference suppression is performed based on feedback weights of the upstream and downstream interference layers of the more than one sequence of data layers, wherein the at least one memory including computer program code is configured to, with the at least one processor, cause the apparatus to: blind detecting feedback weights associated with the upstream interference layer sequence, wherein the detecting feedback weights are zero based on residual interference for the data layer sequence, wherein the antenna port sequence for the 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 medium access control element, wherein interference suppression comprises using a sequence of antenna ports to determine at least one sequence of interference data layers for use by a user equipment in upstream communication, wherein at least one demodulation reference signal port is assigned according to a non-linear precoding layer order of more than one sequence of data layers, wherein at least one memory comprising computer program code is configured to, with at least one processor, cause the apparatus to: a one-bit indicator indicating that the data layer sequence port order corresponds to the nonlinear precoding layer order is received from the network node via downlink signaling, and wherein the one-bit indicator indicates whether the demodulation reference signal port corresponds to the pre-cancellation order.

In another example aspect of the invention, there is a method comprising: transmitting, by a network node of a communication network towards a user equipment, more than one data layer sequence associated with feedback weights in transmissions from the network node of the communication network, wherein the more than one data layer sequence is ordered for successive interference pre-cancellation, wherein the more than one data layer sequence is used by the user equipment to perform interference suppression for communications using the more than one data layer sequence.

Another example embodiment is a method comprising the above paragraph, wherein at least one antenna port is assigned to each of the more than one data layer sequences, 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 the data layer identifies whether the data layer is associated with an upstream or a downstream interference layer, wherein interference suppression is performed based on feedback weights of the upstream and downstream interference layers of the more than one data layer sequences, wherein interference suppression comprises blind detection of feedback weights associated with the upstream interference layer sequences, wherein detection of the feedback weights is based on residual interference for the data layer sequences being zero, wherein the antenna port sequence of the target data layer sequence for the user device is transmitted to the user device in downlink control information via one of: a radio resource control configuration or medium access control element, wherein interference suppression comprises determining at least one interference data layer sequence for use by a user equipment using an antenna port sequence, wherein at least one demodulation reference signal port is assigned according to a non-linear precoding layer order of more than one data layer sequence, and there is a one bit indicator indicating to the user equipment via downlink signaling that the data layer sequence port order corresponds to the non-linear precoding layer order, wherein the one bit indicator indicates whether the demodulation reference signal port corresponds to a pre-cancellation order.

In another example aspect of the invention there is an apparatus, such as a network side apparatus, comprising: means for transmitting, by a network node of a communication network, more than one data layer sequence towards a user equipment, the more than one data layer sequence being associated with feedback weights in transmissions from the network node of the communication network, wherein the more than one data layer sequence is ordered for successive interference pre-cancellation, wherein the more than one data layer sequence is used by the user equipment to perform interference suppression for communications using the more than one data layer sequence.

Another example embodiment is an apparatus comprising the above paragraph, wherein at least one antenna port is assigned to each of the more than one data layer sequences, 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 the data layer identifies whether the data layer is associated with an upstream or downstream interference layer, wherein interference suppression is performed based on feedback weights of the upstream and downstream interference layers of the more than one data layer sequences, wherein interference suppression comprises blind detection of feedback weights associated with the upstream interference layer sequences, wherein detection of the feedback weights is based on residual interference for the data layer sequences being zero, wherein the antenna port sequence of the target data layer sequence for the user device is transmitted to the user device in downlink control information via one of: a radio resource control configuration or medium access control element, wherein interference suppression comprises determining at least one interference data layer sequence for use by a user equipment using an antenna port sequence, wherein at least one demodulation reference signal port is assigned according to a non-linear precoding layer order of more than one data layer sequence, and there is means for transmitting, by a network node via downlink signaling, to the user equipment a one-bit indicator indicating that the data layer sequence port order corresponds to the non-linear precoding layer order, wherein the one-bit indicator indicates whether the demodulation reference signal port corresponds to a pre-cancellation 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, wherein the at least one memory and the computer program code are configured to, with the at least one processor, cause the apparatus at least to: transmitting, by a network node of a communication network towards a user equipment, more than one data layer sequence associated with feedback weights in transmissions from the network node of the communication network, wherein the more than one data layer sequence is ordered for successive interference pre-cancellation, wherein the more than one data layer sequence is used by the user equipment to perform interference suppression for communications using the more than one data layer sequence.

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

Drawings

The foregoing and other aspects of embodiments of the invention will become more apparent in the following detailed description when read in conjunction with the accompanying drawings, in which:

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

FIG. 1B shows an example formula for two user devices and two layers per user device case according to an example embodiment of the invention;

FIG. 2 shows a block diagram of a system according to an example embodiment of the invention;

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

FIG. 4 shows signaling and processing diagrams of operations according to an example embodiment 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 8B each illustrate a method according to an example embodiment of the invention that may be performed by an apparatus.

Detailed Description

In the present invention, an enhanced network assisted feedback weight detection scheme is presented that supports improved interference measurement at the receiver.

The NR standard for MIMO (release 15) is based on linear precoding. To further improve the throughput of MU-MIMO transmissions, nonlinear precoding (NLP) is now considered a candidate technique for higher versions of NR. Tomlinson-Harashima precoding (THP) is the most promising NLP solution, which greatly reduces complexity at the cost of reduced modulo loss and power loss.

The main challenge of THP is that its performance under realistic assumptions is still unclear. The present report is directed to enhancing THP performance under non-ideal Channel State Information (CSI). The THP system diagram is shown in fig. 1A.

In THP, first pair by pairThe data layers, such as with the original symbols 101, as shown in fig. 1A, are ordered for successive interference pre-cancellation. This ordering is typically done in a "worst-layer-first" manner to balance the performance of the different layers. In this report, it is assumed that the original symbol layer x= [ x ] ₁ ；x ₂ ；…x _L ]Has been ordered, where L represents the number of layers.

Successive interference pre-cancellation is performed by a feedback filter 110 and a modulo device (such as MOD 120 for data as discussed herein and shown in fig. 1A) to generate a pre-distorted symbol s= [ s ₁ ；s ₂ ；...s _L ]. The predistortion symbol of layer i is based on the formula (hereinafter 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 ，

wherein b _i，j Is the ith row and jth column element, p, of the feedback matrix B _i Is modulo shift (modulo shift). Item b _i， _j s _j Interference from the upstream layer j is expected to cancel at the receiver (j < i). To limit the transmit power, a modulo shift is added.

As shown in step 140 of fig. 1A, the predistorted symbol passes through a feedforward filter f= [ F ] ₁ ，f ₂ ，...f _L ]Is precoded to generate symbols at the TX antennas, where Is the feed forward precoding vector for layer i. TX symbol passes through physical channel h= [ H ] ₁ ；H ₂ ；...H _N ]Is transmitted and becomes a symbol at the RX antenna, wherein +.>Is the physical channel of UE N, N being the total number of UEs. M is M _R And M _T The number of RX antennas per UE and the number of TX antennas at the base station, respectively.

The RX symbols at the RX antenna are combined by a receive filter W, such as with the receive filter W shown in FIG. 1A, to obtain the signal as shown in FIG. 1AWhere y= [ y ] ₁ ；y ₂ ；...y _L ]WhereinIs a block diagonal matrix comprising a merge weight vector for each layer i +.>The combining weight vector in THP is typically designed by the base station and signaled to the UE either explicitly or implicitly.

The end-to-end transform from pre-distorted to post-combined symbols is y=w×hfs, such as with the channel and interference estimation module 150 shown in fig. 1A to ignore noise. By replacing s with formula F1 as described above, a formula (hereinafter referred to as formula F2) can be obtained:

where u (i) is the target UE of layer i.

The following and formulas as in fig. 1B give examples of cases for two UEs and two layers per UE.

The first term in equation F2, as shown above, is the received desired signal and modulo shift. The modulo shift will be removed by the modulo device at the receiver. The second term in equation F2 is the sum of the residual interference from each upstream layer j < i. In the ideal case of CSI, channel H _u(i) Is completely known at the TX end and the base station can use feedback weightsTo completely cancel the interference. The third term in equation F2 is the sum of the residual interference from each downstream layer k > i. In the ideal case of CSI, the base station can jointly design the feedforward filter F and the receiving filter W to obtain a lower triangular effective channel H ^eff =whf, where>Thus, interference from downstream layers is also eliminated. It is concluded that in the ideal CSI case, the THP transmission can be made undisturbed and pre-cancellation (feedback) is only required for the upstream interfering layer

There is a problem in that CSI is mainly undesirable in an actual network due to delay between CSI measurement and data transmission, limited resolution of CSI reporting, and measurement errors. This means that the channel known to the base station is different from the channel H used for data transmission. Thus, feedback, feedforward, and receive filters designed by the base station cannot completely cancel the interference.

For linear precoding, interference cancellation is performed not only at the base station but also at the receiver, as the UE can measure interference from the DMRS and reject the receiver with interference, such as an MMSE receiver.

Unlike linear precoding, with NLP, RX-side interference suppression becomes more difficult. By decoding the DMRS, the UE can know the channel from each RX to each precoding layer. The receiver of layer i may detect the DMRS of layer j' and acquire a measurement channel

The total channel measured from DMRS is

By substituting the measured channel into equation F2, an equation (referred to herein as equation F3) is derived:

from the second term of equation F3 shown above, it can be seen that the channel information for interference from the upstream layer is incomplete, since the receiver only knows the measured channelAnd->But does not know the feedback weight b _i，f . Furthermore, the receiver does not even know whether the interfering layer is an upstream layer or a downstream layer, since it does not have any information about how the layers are ordered at the base station. Therefore, it is difficult for the receiver to find the combining weight vector +.>

In addition to the computation of the combining vector, the log-likelihood ratio computation for demodulation also depends on the interference estimate, and if the estimated interference is inaccurate, the demodulation performance may be degraded.

In previous submissions, focus was on designing the receive filters (combining vectors) at the base station. The base station selects a combining vector from the codebook and explicitly transmits a corresponding index to the UE. The receive filter may be designed as an MRC filter, thus avoiding additional signaling. It is assumed that the UE directly uses a reception filter designed by the base station, and thus the UE cannot further suppress interference due to non-ideal CSI.

Other submissions propose another type of DMRS that applies not only a feed-forward DMRS, but also a feedback filter. To distinguish between these two types of DMRS, a conventional DMRS is defined that applies only a feedforward DMRS as a "feedforward DMRS" and a DMRS as a "complete DMRS". The difference between the feed-forward DMRS and the complete DMRS is shown in fig. 3. As shown in fig. 3, there is a complete DMR 310, and the complete DMR 310 is fed back through a feedback filter B-1 312 and a feedforward DMRs 320 to output a feedforward filter F315.

The channel measured from the complete DMRS is expected to implicitly include the effects from the feedback filter. However, the interference pre-cancellation procedure for the complete DMRS is still different from the data. For example, there are modulo devices for data but not for DMRS. The modulo device must be excluded from the DMRS because the modulo shift is unknown to the UE, but the UE needs to know the transmitted symbols completely for DMRS-based channel estimation.

Complete DMRS has two problems due to the lack of modulo shifting. First, since there is no modulo device to limit power, the transmission power of DMRS becomes higher than data. This means that in practice power backoff must be applied to the complete DMRS. Second, the modulo device for the data at RX only cancels the modulo shift of the target layer, and does not cancel the modulo shift of the interference. Such modulo shifting typically causes interference to the data differently than the interference measured from the DMRS.

Before describing an example embodiment of the invention in more detail, reference is made to fig. 2. FIG. 2 shows a block diagram of one possible and non-limiting exemplary system in which an exemplary embodiment of the invention may be practiced. In fig. 2, a Mobile Station (MS) 110 is in wireless communication with a wireless network 100. The MS110 or UE is wireless or wired, typically a mobile device that can access a wireless network. MS110 includes one or more processors 120, one or more memories 125, and one or more transceivers 130 interconnected by one or more buses 127. Each of the one or more transceivers 130 includes a receiver Rx 132 and a transmitter Tx 133. One or more of buses 127 may be an address, data, or control bus, and may include any interconnection mechanism, such as a series of lines on a motherboard or integrated circuit, optical fibers, or other optical communication device, etc. One or more transceivers 130 are connected to one or more antennas 128. The one or more memories 125 include computer program code 123.MS110 may include a precoding processing element (PPu) module 140, e.g., a precoding processor element (PPu) for a UE such as MS110, PPu module 140 configured to perform at least precoding-related signal detection and processing of example embodiments of the present invention as described herein. Note that the use of PPU is optional and that example embodiments of the invention may be performed with or by another module or processor, such as processor(s) 120. PPu module 140 includes one or both of portions 140-1 and/or 140-2, which may be implemented in a variety of ways. PPu module 140 may be implemented in hardware as PPu module 140-1, such as being implemented as part of one or more processors 120. PPu module 140-1 may also be implemented as an integrated circuit or by other hardware, such as a programmable gate array. In another example, PPu module 140 can be implemented as PPu module 140-2 and ppu module 140-2 is implemented as computer program code 123 and executed by one or more processors 120. For example, 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 described herein. MS110 communicates with gNB 170 via wireless link 111. Further, it should be noted that the labeling of MS110 as in fig. 2 is non-limiting, and that the operations of MS110 may similarly be performed by a device labeled as a user equipment or UE, or a user equipment or UE device or network device, a mobile device (MS), a wireless device, and/or an 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 communication technologies including conventional communication technologies) that provides access to the wireless network 100 by wireless devices such as the MS 110. The gNB 170 includes one or more processors 152, one or more memories 155, one or more network interfaces (N/W I/F) 161, and one or more transceivers 160 interconnected by one or more buses 157. Each of the one or more transceivers 160 includes a receiver Rx162 and a transmitter Tx 163. 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 (PPu module 150) for the gNB that is configured to perform at least precoding-related signaling and processing in accordance with the example embodiments of the invention described herein. Note again that the use of PPU is optional and that example embodiments of the invention may be performed with or by another module or processor, such as processor(s) 120. PPu module 150 includes one or both of portions PPu module 150-1 and/or PPu module 150-2, which may be implemented in a variety of ways. PPu module 150 can be implemented in hardware as PPu module 150-1, such as being implemented as part of one or more processors 152. PPu module 150-1 may also be implemented as an integrated circuit or by other hardware, such as a programmable gate array.

In another example, PPu module 150 can be implemented as PPu module 150-2 and ppu module 150-2 as computer program code 153 and executed by one or more processors 152. For example, the one or more memories 155 and the computer program code 153 are configured, with the one or more processors 152, to cause the gNB170 to perform one or more of the signaling and processing operations at least related to precoding as described herein. One or more network interfaces 161 communicate over the network, such as via links 176 and 131. Two or more gnbs 170 may communicate using, for example, links 176. The link 176 may be wired or wireless or both and may implement, for example, 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 optic or other optical communication devices, wireless channels, etc. For example, one or more transceivers 160 may be implemented as a Remote Radio Head (RRH) 195, while other elements of the gNB170 are physically located in different locations than the RRH. The RRH may be part of a Base Transceiver Station (BTS) that communicates with devices including the gNB170 as in fig. 2. The RRH can have one or more buses 157, which can be implemented in part as fiber optic cables, to connect other elements of the gNB170 to a Remote Radio Head (RRH) 195.

Note that the description herein indicates that "cell" performs a function, but it should be clear that the gcb forming the cell may perform a function. The cell forms part of a gNB or eNB. That is, there may be multiple cells per gNB or eNB.

The wireless network 100 may include a Base Station Controller (BSC) 190, which BSC 190 may include precoding control functionality and provide connectivity to another network, such as a telephone network and/or a data communication network (e.g., the internet). gNB 170 is coupled to BSC 190 via link 131. Link 131 may be implemented as, for example, 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) 180 interconnected by 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, with the one or more processors 175, to cause the BSC 190 to perform one or more operations.

Wireless network 100 may implement network virtualization, a process that combines hardware and software network resources and network functions into a single software-based management entity (i.e., a virtual network). Network virtualization involves platform virtualization, which is typically combined with resource virtualization. Network virtualization is categorized as either external (combining many networks or portions of networks into virtual units) or internal (providing network-like functionality to software containers on a single system). Note that the virtualized entity resulting from network virtualization is still implemented to some extent using hardware such as processors 152 or 175 and memories 155 and 171, and that such virtualized entity also produces technical effects.

Computer readable memories 125, 155, and 171 may be of any type suitable to the local technical environment 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 a memory function. Processors 120, 152, and 175 may be of any type suitable to the local technical environment, 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. Processors 120, 152, and 175 may be means for performing functions such as controlling MS110, gNB 170, and other functions described herein.

Note that any reference to terms used in this specification or tags in any drawing (which may be associated with a particular communication technology) is not limiting (e.g., a gNB or eNB or access node). The example embodiments of the invention described herein may be performed using devices present in GSM/EDGE, LTE, and/or 5G, as well as any devices operating in any other communication technology (e.g., gNB, eNB, BTS, BSC, UE and/or MS). Furthermore, FIG. 2 may be used for operation according to an example embodiment of the present invention between devices such as an MS-BTS-BSC for GSM, a UE-gNB for 5G, and a UE-eNB for LTE. Note that this example is non-limiting, and operations according to example embodiments of the invention may be performed using different devices and/or different examples than the examples.

In general, various embodiments of mobile station 110 may include, but are not limited to, cellular telephones (such as smartphones), 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 having 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., application specific integrated circuits), or a combination of software and hardware. In an example of an embodiment, software (e.g., application logic, instruction set) is maintained on any one of various conventional computer-readable media. In the context of this document, a "computer-readable medium" can be any medium or means that can contain, store, communicate, propagate, or transport the instructions for use by or in connection with the instruction execution system, apparatus, or device (such as a computer), an example of which is described and depicted, for example, in fig. 2. A computer-readable medium may include a computer-readable storage medium or other device that can be any medium 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.

According to an example embodiment of the invention, it may be assumed that a feed-forward DMRS is used and that there is an explicit signaling or implicit protocol with respect to the receive filters of the base station design. Unlike the prior art, the exemplary embodiments of the present invention enable the UE to further adjust the receive filter to improve interference suppression. The receive filter designed by the base station gives only information about what receiver is supposed on the TX side, but not necessarily the final receive filter on the RX side according to an embodiment of the invention.

Example embodiments of the invention assume that the base station should assist the UE in distinguishing between upstream and downstream interference layers. This may be done implicitly by assigning DMRS ports according to layer order, e.g. DMRS port i should be assigned to the i-th layer. Since the DMRS port index of the target layer is signaled in the Downlink Control Information (DCI), the receiver of layer i will know that layer 1, 2.

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

The receiver should combine the upstream and downstream interference into a final estimated interference and arrive at an interference rejection receive filter. Although the residual upstream interference is assumed to be 0 in the case of the base station designed receive filter, the UE may eventually select a different receive filter that suppresses the downlink interference, but keeps the residual upstream interference non-zero and obtains a better trade-off.

More generally, the UE should perform blind detection only for the pre-cancelled interference layer, while performing explicit detection for the remaining layers. In some cases, not all upstream layers need to be pre-eliminated. For example, the feedforward and receive filters have been designed to ensure that the intra-UE interference is already 0 before the interference pre-cancellation, so there is no pre-cancellation for the intra-UE interference, i.e., b when u (i) =u (j) _i，j =0. In this case, even if j is an upstream layer of the target layer i, blind detection is not required for the interference layer j when u (i) =u (j).

The proposed signaling and processing diagram can be found in fig. 4. As shown in fig. 4, the gNB 170 sends information 410 towards the UE 110. Information 410 includes RX filter information and layer order correspondence indicators. Further, as shown in fig. 4, the gNB 170 sends information 420 to the UE 110, the information 420 including the feedforward DMRS and the data. With this information, UE 110 may derive information 430 as shown in fig. 4. Information 430 includes channel estimates for the target signal, the resulting gNB designed RX filter, channel estimates for the interfering layer, blind detection of feedback weights, calculation of interference with feedback weights for blind detection, and derivation of an interference-suppressed RX filter. As shown in fig. 4, some new components introduced according to some example embodiments of the invention are marked in bold in information 430.

First, gNB should send RX filters with respect to base station designIs a piece of information of (a). Filter->Use on the TX side to calculate feedback weights +.>This signaling is not new, but is necessary for all THP solutions based on feed-forward DMRS. From this point on, it can be assumed that the RX filter designed by the base station is an MRC receiver, and this assumption is sent to the UE as RX filter information. It can also be assumed that pre-cancellation is avoided for intra-UE interference.

Second, the gNB should transmit a one-bit layer order correspondence indicator indicating whether the DMRS port corresponds to the pre-erasure order of THP. The layer order correspondence indicator may be sent via any downlink signaling, such as 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 may also explicitly transmit DMRS port indexes of all pre-cancellation layers to the target layer, but overhead may increase.

It may be assumed that layer correspondence is enabled and focus is placed on the one layer i reception process in the following analysis, according to embodiments described herein.

For the layer i to be a layer,the target UE should first estimate the channel of the desired signal from DMRS port i It should also derive the RX filter of the base station design +.>Which is an MRC combiner.

Fig. 5 shows table i. Fig. 5 shows parameters and configurations for simulation settings using an example embodiment of the invention.

For each non-UE inner upstream layer j (j < i and u (j) notequ (i)), the interfering channel should be estimated from DMRS port jThe receiver knows that layer j has been fed back on the TX side with weights b _i，j Pre-cancellation, but not knowing b _i，j Is a value of (2). Receiver designed according to formula F3 and assuming use of base station>The blind detection of the feedback weights should be based on a time-residual interference of 0To do so, i.e. to add->Wherein->Is the feedback weight b _i，j Is a function of the estimate of (2). After deriving the estimated feedback weights, the blind detected interference channel after pre-cancellation is calculated as +.>

For each intra-UE interference or downstream layer k (u (k) =u (i) or k > i), the channel is interferedShould be estimated from DMRS port k. There is no pre-cancellation for layer kThus, no blind detection is required.

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

wherein the method comprises the steps ofIs the covariance matrix of inter-cell interference and noise (non-MU-MIMO interference and noise) that can be estimated in the same manner as in the linear precoding case. The MMSE receiver of layer i is calculated as +. >w _i Used as final receive filter instead of receive filter designed for base station +.>

In general, w is when the first term in equation F4 dominates _i Will approachSince it is assumed that the interference corresponding to the first term is by using +.>Is completely eliminated as a receive filter. Otherwise, w _i Possibly with->Completely different. More specifically, when the target layer i is the bottom layer, the final reception weight is generally closer to the receiver of the base station design, and when i is the top layer, the final reception weight is substantially different from the receiver of the base station design.

For the first layer (i=1), there is no pre-cancelled interference and therefore no blind detection. All interference can be detected explicitly and the interference suppression capability is the same as in the linear precoding case. For other layers, the effectiveness of interference suppression is still less than in the linear case, since the feedback weights for blind detection are not necessarily accurate. In any case, for layers with explicitly detected interference, the interference suppression capability is at least partially enabled.

As an alternative to the above procedure, each layer detection of the downstream layer may also be skipped. Instead, the UE may subtract the detected DMRS of the target layer, intra-UE interference layer, and upstream layer from the received signal, and treat the remaining signals as total interference from the downstream layer, other cells, and noise.

As shown in fig. 6 and 7, comparing four THP DMRS and receiver schemes in a link layer simulation, includes:

1) Baseline schemes of feed forward DMRS and MRC receivers;

2) Complete DMRS and MMSE receiver, the ideal assumption is that DMRS has no power limitation;

3) A feed-forward DMRS and MMSE receiver with blind detection of feedback weights, which is the solution proposed in the present invention; and

4) The ideal case of feed-forward DMRS and MMSE receivers with ideal knowledge of feedback weights is not practical.

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

Fig. 6 and 7 show simulation results for line-of-sight (LoS) and non-line-of-sight (NLoS) channel models, according to an example embodiment of the present invention.

As shown in fig. 6, a graph identifying signal-to-noise ratio (SNR) for line of sight (LoS) based on total spectral efficiency is shown. As shown in fig. 6, there are feedforwardmrs_mrc 630, fulldmrs_mmse 640, feedforwardmrs_blindfeedback detect_mmse 620, and feedforwardmrs_idealfeedback detect_mmse 610.

As shown in fig. 7, a graph is shown that identifies the signal-to-noise ratio (SNR) for non-line-of-sight (NLoS) based on total spectral efficiency. As shown in fig. 6, there are feedforwardmrs_mrc 740, fulldmrs_mmse 730, feedforwardmrs_blindfeedback detect_mmse 720, and feedforwardmrs_idealfeedback detect_mmse 710.

As can be seen from fig. 6 and 7, while the proposed scheme (feedforward DMRS with blind detection) may not be as good as ideal, it is always better than two existing solutions. Gains over the baseline scheme result from accurate explicit detection of downstream and intra-UE interference, as well as best effort blind detection of pre-cancellation interference. The gain over the full DMRS scheme comes from the fact that: the interference measured with a complete DMRS is inaccurate due to the lack of modulo in the DMRS.

In fig. 6, the performance difference between the four schemes is relatively small. The LoS channel is stable, so the CSI is near ideal and the gain from interference suppression is limited. In contrast, for NLoS channels, the interference suppression gain is very significant.

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

Fig. 8A and 8B each illustrate a method that may be performed by an apparatus according to an example embodiment of the invention.

Fig. 8A illustrates operations such as a method that may be performed by a network device such as, but not limited to, a mobile station or user equipment (such as MS110 in fig. 2). As shown in step 810 of fig. 8A, more than one data layer sequence associated with feedback weights in transmissions from a network node of the communication network is identified by a user equipment of the communication network, wherein the more than one data layer sequences are ordered for successive interference pre-cancellation. Interference suppression is then performed by the user equipment for communications using more than one data layer sequence, as shown in step 820 of fig. 8B.

According to an example aspect of the invention described in the preceding paragraph, wherein at least one antenna port is assigned to each of the more than one data layer sequences, wherein the at least one antenna port comprises at least one demodulation reference signal port.

According to an example aspect of the invention described in the preceding paragraph, wherein the at least one demodulation reference signal port of the data layer identifies whether the data layer is associated with an upstream or a downstream interference layer.

According to an example aspect of the invention described in the preceding paragraph, wherein the interference suppression is performed based on feedback weights of upstream and downstream interference layers of more than one data layer sequence.

According to an example aspect of the invention described in the preceding paragraph, there is: the feedback weights associated with the upstream interference layer sequence are blindly detected.

According to an example aspect of the invention described in the preceding paragraph, wherein the detection feedback weight is zero based on a residual interference for the data layer sequence.

According to an example aspect of the invention as described in the preceding paragraph, wherein the antenna port sequence for the target data layer sequence of the user equipment is received by the user equipment in the downlink control information via one of: a radio resource control configuration or a medium access control element.

According to an example aspect of the invention described in the preceding paragraph, interference suppression comprises using the antenna port sequence to determine at least one interference data layer sequence for use by the user equipment in upstream communications.

According to an example aspect of the invention described in the preceding paragraph, 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.

According to an example aspect of the invention described in the preceding paragraph, there is receiving a one-bit indicator from the network node via downlink signaling indicating that the data layer sequence port order corresponds to the nonlinear precoding layer order.

According to an example aspect of the invention described in the preceding paragraph, wherein the one bit indicator indicates whether the demodulation reference signal ports correspond to a pre-cancellation order.

A non-transitory computer readable medium (e.g., memory(s) 125 as shown in fig. 2) stores program code (e.g., computer program code 123 as shown in fig. 2) that is executed by at least one processor (e.g., processor(s) 120 and/or PPu module 140-1, computer program code 123 as shown in fig. 2) to perform at least the operations described in the preceding paragraphs.

According to an example embodiment of the invention as described above, there is an apparatus comprising: means (such as memory(s) 125, computer program code 123, and/or PPU module 140-2, processor(s) 120, and/or PPu module 140-1 in fig. 2) for identifying, by a user equipment (such as MS110 in fig. 2) of a communication network (such as wireless network 100 in fig. 2), more than one data layer sequence associated with feedback weights in transmissions from a network node (such as gNB 170 in fig. 2) of the communication network (such as wireless network 100 in fig. 2), wherein the more than one data layer sequences are ordered for successive interference pre-cancellation. Then, there are means (e.g., memory(s) 125, computer program code 123, and/or PPU module 140-2, processor(s) 120, and/or PPu module 140-1 in fig. 2) for performing interference suppression by a user equipment (e.g., MS110 in fig. 2) for communications using more than one data layer sequence.

In an example aspect of the invention according to the preceding paragraph, wherein at least the means for identifying and executing comprises a non-transitory computer-readable medium [ e.g., memory(s) 125 in fig. 2] encoded with a computer program [ e.g., computer program code 123 and/or PPU module 140-2] executable by at least one processor [ e.g., processor(s) 120 and/or PPu module 140-1 in fig. 2 ].

Fig. 8B illustrates operations such as a method that may be performed by a network device such as, but not limited to, a network node (such as the gNB 170 or base station in fig. 2). As shown in step 850 of fig. 8B, more than one data layer sequence is sent towards the user equipment by the network node of the communication network, the more than one data layer sequence being associated with feedback weights in transmissions from the network node of the communication network. As shown in step 860 of fig. 8B, wherein more than one data layer sequence is ordered for successive interference pre-cancellation. Then, as shown in step 870 of fig. 8B, wherein more than one data layer sequence is used by the user equipment to perform interference suppression for communications using more than one data layer sequence.

According to an example aspect of the invention described in the preceding paragraph, wherein the interference suppression comprises blind detection of feedback weights associated with the upstream interference layer sequence.

According to an example aspect of the invention described in the preceding paragraph, wherein the detection of the feedback weights is based on the residual interference for the data layer sequence being zero.

According to an example aspect of the invention as described in the preceding paragraph, wherein the antenna port sequence for the target data layer sequence of the user equipment is transmitted to the user equipment in the downlink control information via one of: a radio resource control configuration or a medium access control element.

According to an example aspect of the invention as described in the preceding paragraph, wherein interference suppression comprises using the antenna port sequence to determine at least one interference data layer sequence for use by the user equipment.

According to an example aspect of the invention described in the preceding paragraph, comprising: a one-bit indicator indicating that the data layer sequence port order corresponds to the nonlinear precoding layer order is sent by the network node to the user equipment via downlink signaling.

A non-transitory computer readable medium (e.g., memory(s) 155 as shown in fig. 2) stores program code (e.g., computer program code 153 as shown in fig. 2) that is executed by at least one processor (e.g., processor(s) 152 and/or PPu module 150-1, computer program code 153, and/or PPU module 150-2 as shown in fig. 2) to perform at least the operations described in the preceding paragraphs.

According to an example embodiment of the invention as described above, there is an apparatus comprising: means (such as memory(s) 155, computer program code 153, and/or PPU module 150-2, processor(s) 152, and/or PPu module 150-1 in fig. 2) for transmitting, by a network node of a communication network (such as wireless network 100 in fig. 2), more than one sequence of data layers associated with feedback weights in transmissions from the network node of the communication network towards a user equipment (such as MS110 in fig. 2). There are means for more than one data layer sequence to be ordered for successive interference pre-cancellation (such as memory(s) 155, computer program code 153 and/or PPU module 150-2, processor(s) 152 and/or PPu module 150-1 in fig. 2). There are means for more than one data layer sequence to be used by the user equipment to perform interference suppression for communications using more than one data layer sequence (such as memory(s) 155, computer program code 153 and/or PPU module 150-2, processor(s) 152 and/or PPu module 150-1 in fig. 2).

In an example aspect of the invention according to the preceding paragraph, wherein the means for at least transmitting, ordering and executing comprises a non-transitory computer-readable medium [ e.g., memory(s) 155 in fig. 2] encoded with a computer program [ e.g., computer program code 153 and/or PPU module 150-2 in fig. 2] executable by at least one processor [ e.g., processor(s) 152 and/or PPu module 150-1 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 invention may be practiced in various components such as integrated circuit modules. The design of integrated circuits is generally 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 the 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 refer to any direct or indirect connection or coupling between two or more elements, and may encompass the presence of one or more intervening elements between two elements "connected" or "coupled" together. The coupling or connection between the elements may 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 (visible and invisible) regions, as a few 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 present invention, and not in limitation thereof.

Claims

1. A method of communication, comprising:

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

interference suppression is performed by the user equipment for communications using the more than one data layer sequence.

2. The method of claim 1, wherein at least one antenna port is assigned to each of the more than one data layer sequences, wherein the at least one antenna port comprises at least one demodulation reference signal port.

3. The method of 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 or a downstream interference layer.

4. The method of claim 3, wherein the interference suppression is performed based on the feedback weights of the upstream and downstream interference layers of the more than one data layer sequence.

5. A method according to claim 3, comprising:

the feedback weights associated with the upstream interference layer sequence are blindly detected.

6. The method of claim 5, wherein detecting the feedback weight is based on zero residual interference for the data layer sequence.

7. A method according to claim 3, wherein the antenna port sequence for the target data layer sequence of 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.

8. The method of claim 7, the interference suppression comprising determining at least one interference data layer sequence for use by the user equipment in upstream communications using the antenna port sequence.

9. The method according to any of claims 2 to 8, 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.

10. The method of claim 9, comprising: a one bit indicator is received from the network node via downlink signaling, the one bit indicator indicating that a data layer sequence port order corresponds to the nonlinear precoding layer order.

11. The method of claim 10, wherein the one bit indicator indicates whether a demodulation reference signal port corresponds to a pre-cancellation order.

12. An apparatus for communication, comprising:

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

means for performing interference suppression by the user equipment for communications using the more than one data layer sequence.

13. The apparatus of claim 12, wherein at least one antenna port is assigned to each of the more than one data layer sequences, wherein the at least one antenna port comprises at least one demodulation reference signal port.

14. The apparatus of 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 or a downstream interference layer.

15. The apparatus of claim 14, wherein the interference suppression is performed based on the feedback weights of the upstream and downstream interference layers of the more than one data layer sequence.

16. The apparatus of claim 14, comprising:

17. The apparatus of claim 16, wherein detecting the feedback weight is based on zero residual interference for the data layer sequence.

18. The apparatus of claim 14, wherein the antenna port sequence for the target data layer sequence of 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.

19. The apparatus of claim 18, the interference suppression comprising determining at least one interference data layer sequence for use by the user equipment in upstream communications using the antenna port sequence.

20. The apparatus according to any of claims 13 to 19, 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.

21. The apparatus of claim 20, comprising: a one bit indicator is received from the network node via downlink signaling, the one bit indicator indicating that a data layer sequence port order corresponds to the nonlinear precoding layer order.

22. The apparatus of claim 21, wherein the one bit indicator indicates whether a demodulation reference signal port corresponds to a pre-cancellation order.

23. A method of communication, comprising:

transmitting, by a network node of a communication network, more than one data layer sequence towards a user equipment, the more than one data layer sequence being associated with feedback weights in transmissions from the network node of the communication network, wherein the more than one data layer sequence is ordered for successive interference pre-cancellation, wherein the more than one data layer sequence is used by the user equipment to perform interference suppression for communications using the more than one data layer sequence.

24. The method of claim 23, wherein at least one antenna port is assigned to each of the more than one data layer sequences, wherein the at least one antenna port comprises at least one demodulation reference signal port.

25. The method of 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 or a downstream interference layer.

26. The method of claim 25, wherein the interference suppression is performed based on the feedback weights of the upstream and downstream interference layers of the more than one data layer sequence.

27. The method of claim 25, wherein the interference suppression comprises: blind detection of feedback weights associated with upstream interference layer sequences.

28. The method of claim 27, wherein the detection of the feedback weights is based on zero residual interference for the data layer sequence.

29. The method of claim 25, wherein the antenna port sequence for the target data layer sequence of the user equipment is transmitted to the user equipment in downlink control information via one of: a radio resource control configuration or a medium access control element.

30. The method of claim 29, wherein the interference suppression comprises using the antenna port sequence to determine at least one interference data layer sequence for use by the user equipment.

31. The method according to any of claims 24 to 30, 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.

32. The method of claim 31, comprising: a bit indicator is sent by the network node to the user equipment via downlink signaling, the bit indicator indicating that a data layer sequence port order corresponds to the nonlinear precoding layer order.

33. The method of claim 32, wherein the one bit indicator indicates whether a demodulation reference signal port corresponds to a pre-cancellation order.

34. An apparatus for communication, comprising:

means for transmitting, by a network node of a communication network, more than one data layer sequence towards a user equipment, the more than one data layer sequence being associated with feedback weights in transmissions from the network node of the communication network, wherein the more than one data layer sequence is ordered for successive interference pre-cancellation, wherein the more than one data layer sequence is used by the user equipment to perform interference suppression for communications using the more than one data layer sequence.

35. The apparatus of claim 34, wherein at least one antenna port is assigned to each of the more than one data layer sequences, wherein the at least one antenna port comprises at least one demodulation reference signal port.

36. The apparatus of 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 or a downstream interference layer.

37. The apparatus of claim 36, wherein the interference suppression is performed based on the feedback weights of the upstream and downstream interference layers of the more than one data layer sequence.

38. The apparatus of claim 36, wherein the interference suppression comprises: blind detection of feedback weights associated with upstream interference layer sequences.

39. The apparatus of claim 38, wherein the detection of the feedback weights is based on zero residual interference for the data layer sequence.

40. The apparatus of claim 36, wherein the antenna port sequence for the target data layer sequence of the user equipment is transmitted to the user equipment in downlink control information via one of: a radio resource control configuration or a medium access control element.

41. The apparatus of claim 40, wherein the interference suppression comprises using the antenna port sequence to determine at least one interference data layer sequence for use by the user equipment.

42. The apparatus according to any of claims 35 to 41, 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.

43. The apparatus of claim 42, comprising: means for transmitting, by the network node, a one bit indicator to the user equipment via downlink signaling, the one bit indicator indicating that a data layer sequence port order corresponds to the nonlinear precoding layer order.

44. The apparatus of claim 43, wherein the one bit indicator indicates whether a demodulation reference signal port corresponds to a pre-cancellation order.