CN112771786A

CN112771786A - Network assisted feedback weight detection for non-linear precoding

Info

Publication number: CN112771786A
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 Networks Oy
Current assignee: Nokia Shanghai Bell Co Ltd; Nokia Oyj
Priority date: 2018-09-19
Filing date: 2018-09-19
Publication date: 2021-05-07
Anticipated expiration: 2038-09-19
Also published as: WO2020056650A1; CN112771786B

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. Additionally, sending, by a network node of the communication network towards the user equipment, more than one data layer sequence associated with feedback weights in transmissions from the network node of the communication network is also performed, 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 non-linear precoding

Technical Field

The teachings in accordance with the exemplary embodiments of this invention relate generally to enhanced network assisted feedback weight detection schemes and, more particularly, relate to enhanced network assisted feedback weight detection schemes that support improved interference measurements at a 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. Thus, 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 specification and/or in the drawings are defined as follows:

NR new radio

NLP nonlinear precoding

MU multiuser

MIMO multiple input multiple output

THP Tomlinson-Harashima precoding

TX transmission

RX-reception

UE user equipment

DMRS demodulation reference signals

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 the multiple antenna technique, precoding is used to map modulation symbols onto different antennas. The type of precoding depends on the multi-antenna technique used as well as the number of layers and the number of antenna ports. The purpose of using 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 issue, known reference signals may be transmitted with the data and used by the receiver to reduce or eliminate interference for signaling transmission and/or demodulation.

Example embodiments of the present invention are directed to 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 method of the above 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 the data layer identifies whether the data layer is associated with an upstream interference layer or a downstream interference layer, wherein interference suppression is performed based on feedback weights of an upstream interference layer and a downstream interference layer of the more than one data layer sequence, there is blind detection of feedback weights associated with the upstream interference layer sequence, wherein detecting the feedback weights is based on the residual interference being zero for the data layer sequence, wherein an antenna port sequence of a target data layer sequence for 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, wherein interference suppression comprises using an antenna port sequence to determine at least one interfering data layer sequence 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 data layer sequence, there is received 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: 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 sequences are 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 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 the data layer identifies whether the data layer is associated with an upstream interference layer or a downstream interference layer, wherein interference suppression is performed based on feedback weights of an upstream interference layer and a downstream interference layer of more than one data layer sequence, there being means for blindly detecting the feedback weights associated with the upstream interference layer sequence, wherein detecting the feedback weights is based on the residual interference being zero for the data layer sequence, wherein an antenna port sequence of a target data layer sequence for 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, wherein interference suppression comprises using an antenna port sequence to determine at least one interfering data layer sequence 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 data layer sequence, there being means for receiving a one-bit indicator 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: 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 apparatus of 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 a data layer identifies whether the data layer is associated with an upstream interference layer or a downstream interference layer, wherein interference suppression is performed based on feedback weights of the upstream interference layer and the downstream interference layer of the more than one data layer sequences, wherein the at least one memory including the computer program code is configured to, with the at least one processor, cause the apparatus to: blindly detecting feedback weights associated with an upstream interference layer sequence, wherein detecting the feedback weights is based on a residual interference for a data layer sequence being zero, wherein an antenna port sequence of a target data layer sequence for a 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 an antenna port sequence to determine at least one interfering data layer sequence 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 data layer sequence, wherein at least one memory including computer program code is configured, with the at least one processor, to cause the apparatus to: receiving a one-bit indicator from a network node via downlink signaling indicating that a data layer sequence port order corresponds to a non-linear pre-coding layer order, and wherein the one-bit indicator indicates whether a demodulation reference signal port corresponds to a 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 method of the above 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 the data layer identifies whether the data layer is associated with an upstream interference layer or a downstream interference layer, wherein interference suppression is performed based on feedback weights of an upstream interference layer and a downstream interference layer of more than one data layer sequence, wherein the interference suppression comprises blind detection of feedback weights associated with the upstream interference layer sequence, wherein the detection of the feedback weights is based on the residual interference for the data layer sequence being zero, wherein the antenna port sequence for the target data layer sequence of 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 interference suppression comprises using an antenna port sequence to determine at least one interfering data layer sequence 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 more than one data layer sequence, and there is a one-bit indicator sent by the network node to the user equipment via downlink signaling 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 another example aspect of the present invention, there is an apparatus, such as a network-side apparatus, comprising: means for 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 apparatus of the above 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 the data layer identifies whether the data layer is associated with an upstream interference layer or a downstream interference layer, wherein interference suppression is performed based on feedback weights of an upstream interference layer and a downstream interference layer of more than one data layer sequence, wherein the interference suppression comprises blind detection of feedback weights associated with the upstream interference layer sequence, wherein the detection of the feedback weights is based on the residual interference for the data layer sequence being zero, wherein the antenna port sequence for the target data layer sequence of 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 interference suppression comprises using an antenna port sequence to determine at least one interfering data layer sequence 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 more than one data layer sequence, and there is means for sending a one-bit indicator indicating that the data layer sequence port order corresponds to the non-linear precoding layer order to the user equipment via downlink signaling by the network node, 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 apparatus of the above 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 the data layer identifies whether the data layer is associated with an upstream interference layer or a downstream interference layer, wherein interference suppression is performed based on feedback weights of an upstream interference layer and a downstream interference layer of more than one data layer sequence, wherein the interference suppression comprises blind detection of feedback weights associated with the upstream interference layer sequence, wherein the detection of the feedback weights is based on the residual interference for the data layer sequence being zero, wherein the antenna port sequence for the target data layer sequence of the user equipment is sent to 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 an antenna port sequence to determine at least one interfering data layer sequence 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 more than one data layer sequence, and wherein at least one memory including computer program code is configured, with the at least one processor, to cause the apparatus to: transmitting, by the network node to the user equipment via downlink signaling, a one-bit indicator indicating that the data layer sequence port order corresponds to the non-linear pre-coding layer order, wherein the one-bit indicator indicates whether the demodulation reference signal port corresponds to the pre-cancellation order.

Drawings

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

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

FIG. 1B illustrates an example formula for the case of two user devices and two layers per user device, according to an example embodiment of the present 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 illustrates a signaling and processing diagram of operations according to an example embodiment of the present invention;

FIG. 5 shows simulation settings Table 1;

fig. 6 shows the results of link-level simulation 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 supporting improved interference measurements at the receiver is proposed.

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

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

In THP, data layers such as those with original symbols 101 as shown in fig. 1A are first ordered one after the other 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, assume that the original symbol layer x ═ x₁；x₂；...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 modulus device (such as the MOD 120 for data as discussed herein and shown in fig. 1A) to generate a pre-distorted symbol s ═ s₁；s₂；...s_L]. The sign of the predistortion for layer i is based on the formula (hereinafter referred to as formula F1):

s_i＝MOD(x_i-∑_j＜ib_i，js_j)＝x_i-∑_j＜ib_i，js_j+p_i，

wherein b is_i，jIs the ith row and jth column element, p, of the feedback matrix B_iIs a modulo shift. Item b_i， _js_jThe interference from the upstream layer j is expected to cancel at the receiver (j < i). To limit the transmit power, the modulo shift is increased.

As shown in step 140 of fig. 1A, the predistorted symbol is passed through a feedforward filter F ═ F₁，f₂，...f_L]Is precoded to generate symbols at the TX antennas, wherein

Is the feed forward precoding vector for layer i. TX symbol over physical channel H ═ H₁；H₂；...H_N]Is transmitted and becomes a symbol at the RX antenna, where

Is the physical channel of UE N, N being the total number of UEs. M_RAnd M_TRespectively the number of RX antennas per UE and the number of TX antennas at the base station.

The RX symbols at the RX antennas are combined by a receive filter W, such as with the receive filter W shown in fig. 1A, to obtain post-combined symbols 160 as shown in fig. 1A, where y ═ y₁；y₂；...y_L]Wherein

Is a block diagonal matrix comprising a combining weight vector for each layer i

The combining weight vector in THP is typically designed by the base station and is signaled to the UE explicitly or implicitly.

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

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

The following and equations as in fig. 1B give an example of the case for two UEs and two layers per UE.

The first term in equation F2, shown above, is the received desired signal and the modulo shift. The modulo shift will be removed by a modulo device at the receiver. The second term in the formula F2 is the sum of the residual disturbances from each upstream layer j < i. In the ideal CSI case, channel H_u(i)Is fully known at the TX end and the base station can use the feedback weights

To completely eliminate the interference. The third term in equation F2 is the sum of the residual interference from each downstream layer k > i. Under ideal CSI conditions, the base station can jointly design the feedforward filter F and the receiving filter W to obtain a lower triangular effective channel H^effWHF, wherein

Thus, interference from the downstream layers is also eliminated. The conclusion is that in the ideal CSI case, the transmission of THP can be left undisturbed and pre-cancellation (feedback) is only required for the upstream interference layer

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

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

With NLP, RX side interference suppression becomes more difficult, unlike linear precoding. By decoding the DMRS, the UE can know the channel from each RX to each precoding layer. Layer(s)The receiver of i can detect the DMRS of layer j' and acquire the measurement channel

The total channel measured from DMRS is

By substituting the measured channel into formula F2, the formula (referred to herein as formula F3) results:

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

And

but does not know the feedback weight b_i，j. 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 on how these layers are ordered at the base station. Therefore, it is difficult for the receiver to find a combining weight vector that mitigates interference

In addition to the calculation of the combining vector, the log-likelihood ratio calculation for demodulation depends on the interference estimate, and if the estimated interference is not accurate, the demodulation performance may be degraded.

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

Other submissions propose another type of DMRS, which applies not only feed-forward DMRS, but also feedback filters. In order to distinguish these two types of DMRSs, a conventional DMRS is defined, which applies only a feed-forward DMRS as a "feed-forward DMRS" and applies a DMRS as a "complete DMRS". The difference between the feed-forward DMRS and the full DMRS is shown in fig. 3. As shown in fig. 3, there is a full DMR 310, the full DMR 310 being fed back through feedback filters B-1312 and a feed-forward DMRs 320 to output a feed-forward filter F315.

The channel measured from the full DMRS is expected to implicitly include the impact 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 have full knowledge of the transmitted symbols for DMRS-based channel estimation.

The full DMRS has two problems due to the lack of modulo shift. First, since there is no modulo device to limit power, the transmission power of DMRS becomes higher than data. This means that power compensation must be actually applied to the full DMRS. Second, the modulo device for data at RX only cancels the modulo shift of the target layer, and not the interference. Such a modulo shift typically causes the interference on the data to be different from the interference measured from the DMRS.

Before describing an example embodiment of the present invention in more detail, reference is made to FIG. 2. FIG. 2 illustrates a block diagram of one possible and non-limiting exemplary system in which exemplary 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 UE is wireless or wired, and is typically a mobile device that may 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 by 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 wires on a motherboard or integrated circuit, an optical fiber, or other optical communication device, and so forth. 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 a UE, such as the MS 110, the PPu module 140 being configured to perform at least precoding-related signal detection and processing as described herein for the exemplary embodiments of the invention. Note that the use of a PPU is optional, and example embodiments of the present 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 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, the PPu module 140 may be implemented as PPu module 140-2, the PPu module 140-2 implemented as computer program code 123 and executed by the 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 operations described herein relating to precoding. MS 110 communicates with gNB 170 via wireless link 111. Further, it should be noted that the labeling of the MS 110 as in fig. 2 is non-limiting, and that the operations of the MS 110 may be similarly performed by devices labeled as user equipment or UE, or user equipment or UE devices or network devices, mobile devices (MSs), wireless devices, and/or IoT devices.

The gNB 170(NR/5G NodeB or possibly evolved NB) is a base station (e.g., for LTE Long term evolution, GSM, and other communication technologies including legacy communication technologies) that provides access to the wireless network 100 for 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 Rx 162 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 for the gNB (PPu module 150) 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 a PPU is optional, and example embodiments of the present invention may be performed with or by another module or processor, such as processor(s) 120. PPu module 150 includes one or both of portion PPu module 150-1 and/or PPu module 150-2, which may be implemented in a variety of ways. PPu module 150 may be implemented in hardware as PPu module 150-1, such 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, the PPu module 150 may be implemented as the PPu module 150-2, the PPu module 150-2 implemented as the computer program code 153 and executed by the 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 gNB 170 to perform one or more of at least pre-coding related signaling and processing operations as described herein. One or more network interfaces 161 communicate over a network, such as via

links

176 and 131. Two or more gnbs 170 may communicate using, for example, link 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 wires on a motherboard or integrated circuit, an optical fiber or other optical communication device, a wireless channel, or the like. For example, one or more transceivers 160 may be implemented as Remote Radio Heads (RRHs) 195, while other elements of the gNB 170 are physically located at different locations from the RRHs. The RRHs may be part of a Base Transceiver Station (BTS) that communicates with devices including, for example, the gNB 170 in fig. 2. The RRHs may have one or more buses 157, which may be partially implemented as fiber optic cables, to connect other elements of the gNB 170 to Remote Radio Heads (RRHs) 195.

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

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). The gNB 170 is coupled to the BSC 190 via a 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 to, with the one or more processors 175, cause the BSC 190 to perform one or more operations.

Wireless network 100 may implement network virtualization, which is 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 often combined with resource virtualization. Network virtualization is split either externally (combining many networks or parts of networks into virtual units) or internally (providing network-like functionality to software containers on a single system). Note that the virtualized entities resulting from network virtualization are still implemented to some extent using hardware such as

processors

152 or 175 and

memories

155 and 171, and that such virtualized entities also produce technical effects.

The 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 storage 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 MS 110, gNB 170, and other functions described herein.

Note that any reference to terms used in this specification or labels in any of the figures (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 equipment found in GSM/EDGE, LTE, and/or 5G, as well as any equipment operating in any other communication technology (e.g., a gNB, eNB, BTS, BSC, UE, and/or MS). Furthermore, fig. 2 may be used for operation according to example embodiments 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 present invention may be performed using different devices and/or different examples than those of the example.

In general, the various embodiments of mobile station 110 can include, but are not limited to, cellular telephones (such as smart phones), 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 allowing wireless internet access and browsing, 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, a set of instructions) is maintained on any of a variety of 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 an instruction execution system, apparatus, or device, such as a computer, with one example of a computer being described and depicted, for example, in FIG. 2. A computer-readable medium may include a computer-readable storage medium or other device that may 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 present invention, it may be assumed that a feed-forward DMRS is used, and there is explicit signaling or implicit protocol regarding a reception filter designed by a base station. Unlike the prior art, the exemplary embodiments of this invention enable the UE to further adjust the receive filter to improve interference suppression. The base station designed receive filter gives only information about what receiver is assumed 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 present invention assume that the base station should assist the UE to distinguish between the upstream interference layer and the downstream interference layer. This may be done implicitly by assigning DMRS ports according to the layer order, e.g., DMRS port i should be assigned to layer i. 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.. i-1 is its upstream layer.

For each upstream layer interference, the receiver should blindly detect the feedback weights based on the assumption that the residual interference is 0 after applying the reception filter designed by the base station. 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 the final estimated interference and derive 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 gets a better trade-off.

More generally, the UE should perform blind detection only for the pre-cancelled interference layer, and explicit detection for the remaining layers. In some cases, not all upstream layers need be pre-eliminated. For example, the feed forward and receive filters that have been designed ensure that the intra-UE interference is already 0 before the interference pre-cancellation and therefore not used for pre-cancellation of the intra-UE interference, i.e. when u (i) ═ u (j), b _i，j0. 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 at 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 a layer order correspondence indicator. Further, as shown in fig. 4, the gNB 170 transmits information 420 to the UE 110, the information 420 including the feed-forward DMRS and data. With this information, UE 110 may derive information 430 as shown in fig. 4. Information 430 includes the channel estimate of the target signal, the RX filter designed by the resulting gNB, the channel estimate of the interference layer, blind detection of the feedback weights, calculating interference with the feedback weights for blind detection, and deriving an interference rejection RX filter. As shown in fig. 4, certain new components introduced according to some example embodiments of the invention are marked in bold in information 430.

First, the gNB should transmit an RX filter designed for the base station

The information of (1). Filter with a filter element having a plurality of filter elements

Used at TX side to calculate feedback weights

This signaling is not new, but is necessary for all feed-forward DMRS based THP solutions. From this point on, it can be assumed that the RX filter designed by the base station is the MRC receiver, and this assumption is sent to the UE as RX filter information. It may 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-cancellation order of THP. The layer order correspondence indicator may be transmitted via any downlink signaling, such as RRC configuration, MAC CE, or DCI. The 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 according to embodiments described herein, and the reception process of one layer i is focused on in the following analysis.

For layer i, its target UE should first estimate the channel of the desired signal from DMRS port i

It should also derive the RX filter designed by the base station

Which is the MRC combiner.

Fig. 5 shows table i. FIG. 5 illustrates parameters and configurations for simulation setup using an example embodiment of the present invention.

For each non-UE intra-upstream layer j (j < i and u (j) ≠ u (i)), the interfering channel should be estimated from DMRS port j

The receiver knows that layer j has been fed back with weight b on the TX side_i，jPre-elimination, but not knowing b_i，jThe value of (c). Receiver designed according to formula F3 and assuming use of a base station

The time residual interference is 0, and the blind detection of the feedback weight should be based on

To perform, that is,

wherein

Is the feedback weight b_i，jIs estimated. After deriving the estimated feedback weights, blind detected interference channels after pre-cancellation are calculated as

For each intra-UE interference or downstream layer k (u (k) ═ u (i) or k > i), interfering channels

Should be estimated from DMRS port k. There is no pre-cancellation for layer k and therefore no blind detection is required.

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

wherein

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 in the linear precoding case. MMSE receiver for layer i is calculated as

w_iIs used as a final receiving filter for the signal to be received,rather than the receive filter designed by the base station

Generally, w is when the first term in the formula F4 predominates_iWill be close to

Since it is assumed that the interference corresponding to the first term is used by

Is completely eliminated as a receive filter. Otherwise, w_iMay be combined 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 for the linear precoding case. For the other layers, the effectiveness of interference suppression is still not as good as the linear case, since the feedback weights for blind detection are not necessarily accurate. In any case, for layers with explicitly detected interference, interference suppression capabilities are at least partially enabled.

As an alternative to the above procedure, it is also possible to skip every layer detection of the downstream layers. Instead, the UE may subtract the detected DMRSs of the target layer, the intra-UE interference layer, and the upstream layer from the received signal and treat the remaining signal as total interference from the downstream layer, other cells, and noise.

As shown in fig. 6 and 7, four THP DMRS and receiver schemes are compared in link layer simulations, including:

1) feed forward DMRS and a baseline scheme of the MRC receiver;

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

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

4) this is not practical in practice for the ideal case of feed-forward DMRS and MMSE receivers with ideal knowledge of the feedback weights.

The four schemes compared use the same transmission method at the previously designed base station, including the same feed forward 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 FeedForwardDMRS _ MRC 630, fullldmrs _ MMSE 640, FeedForwardDMRS _ bindfeedbackdetect _ MMSE 620, and FeedForwardDMRS _ IdealFeedbackDetect _ MMSE 610.

As shown in fig. 7, a graph identifying signal-to-noise ratio (SNR) for non-line-of-sight (NLoS) based on total spectral efficiency is shown. As shown in fig. 6, there are FeedForwardDMRS _ MRC 740, fullldmrs _ MMSE 730, FeedForwardDMRS _ bindfeedbackdetect _ MMSE 720, and FeedForwardDMRS _ IdealFeedbackDetect _ MMSE 710.

As can be seen from fig. 6 and 7, although the proposed scheme (feed forward DMRS with blind detection) may still be less good than the ideal case, it is always better than the two existing solutions. Gains beyond the baseline scheme come from accurate explicit detection of downstream and intra-UE interference, as well as best-effort blind detection of pre-cancelled interference. The gain over the full DMRS scheme comes from the fact that: due to the lack of modulo in DMRS, the interference measured with a complete DMRS is inaccurate.

In fig. 6, the performance difference between the four schemes is relatively small. The LoS channel is stable, so the CSI is close to 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 layer order correspondence indicators in RRC configurations, 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 MS 110 in fig. 2). As shown in step 810 of fig. 8A, more than one data layer sequence associated with feedback weights in a transmission from a network node of a communication network is identified by a user equipment of the communication network, wherein the more than one data layer sequence is 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 exemplary aspect of the invention as set forth 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.

According to an example aspect of the invention as set forth 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 interference layer or a downstream interference layer.

According to an exemplary aspect of the invention as set forth in the paragraph above, wherein the interference suppression is performed based on feedback weights of an upstream interference layer and a downstream interference layer of the more than one data layer sequence.

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

According to an exemplary aspect of the invention as set forth in the paragraph above, wherein the detection feedback weights are based on a residual interference for the sequence of data layers being zero.

According to an example aspect of the invention described in the preceding paragraph, wherein the sequence of antenna ports of the target data layer sequence for 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 as set forth in the preceding paragraph, the interference suppression comprises using the sequence of antenna ports to determine at least one sequence of interfering data layers for use by the user equipment in upstream communications.

According to an exemplary aspect of the invention as set forth in the paragraph 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.

According to an exemplary aspect of the invention as described in the paragraph above, there is received from the network node via downlink signaling a one-bit indicator indicating that the data layer sequence port order corresponds to the non-linear pre-coding layer order.

According to an exemplary aspect of the invention as set forth in the paragraph above, wherein the one-bit indicator indicates whether the demodulation reference signal port corresponds to a pre-cancellation order.

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

According to an example embodiment of the present invention as described above, there is an apparatus comprising: 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 identifying, by a user equipment (e.g., MS 110 in fig. 2) of a communication network (e.g., wireless network 100 in fig. 2), more than one data layer sequence associated with feedback weights in transmissions from a network node (e.g., gNB 170 in fig. 2) of the communication network (e.g., wireless network 100 in fig. 2), wherein the more than one data layer sequence is ordered for successive interference pre-cancellation. Then, there are means (such as the memory(s) 125, the computer program code 123, and/or the PPU module 140-2, the processor(s) 120, and/or the PPu module 140-1 in fig. 2) for performing interference suppression by a user equipment (such as the MS 110 in fig. 2) for communications using more than one data layer sequence.

In an example aspect of the invention according to the above 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 in fig. 2 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, computer program code 123 ].

Fig. 8B illustrates operations, such as methods, 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 associated with feedback weights in transmissions from a network node of the communication network is transmitted by the network node of the communication network towards the user equipment. As shown in step 860 of fig. 8B, where more than one data layer sequence is ordered for successive interference pre-cancellation. Then, as shown in step 870 of fig. 8B, where 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.

According to an exemplary aspect of the invention as set forth in the paragraph above, wherein the interference suppression comprises blind detection of feedback weights associated with the upstream interference layer sequence.

According to an exemplary aspect of the invention as set forth in the paragraph above, wherein the detection of the feedback weights is based on a residual interference for the sequence of data layers being zero.

According to an example aspect of the invention as set forth in the preceding paragraph, wherein the sequence of antenna ports of the target data layer sequence for the user equipment is sent 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 set forth in the preceding paragraph, wherein the interference suppression comprises using the sequence of antenna ports to determine the at least one sequence of interfering data layers 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 non-linear precoding layer order is sent by the network node to the user equipment via downlink signaling.

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

According to an example embodiment of the present 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 sending, by a network node of a communication network (such as wireless network 100 in fig. 2), towards a user equipment (such as MS 110 in fig. 2), more than one sequence of data layers associated with feedback weights in transmissions from the network node of the communication network. There are 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 more than one data layer sequence to be ordered for successive interference pre-cancellation. There are 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 more than one data layer sequence to be used by a user equipment to perform interference suppression for communications using more than one data layer sequence.

In an example aspect of the invention according to the above paragraphs, where at least the means for transmitting, ordering and executing comprises a non-transitory computer-readable medium [ such as memory(s) 155 in fig. 2] encoded with a computer program [ such as computer program code 153 in fig. 2 and/or PPU module 150-2] executable by at least one processor [ such as 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, 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 may be physical, logical, or a combination thereof. As used 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) region, 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, 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 sequences are ordered for successive interference pre-cancellation; and

performing, by the user equipment, interference suppression 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 interference layer 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 interference layer and the downstream interference layer of the more than one data layer sequence.

5. The method of claim 3, comprising:

feedback weights associated with upstream interference layer sequences are detected blindly.

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

7. The method of claim 3, wherein the sequence of antenna ports 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 using the antenna port sequence to determine at least one interfering data layer sequence for use by the user equipment in upstream communications.

9. The method of 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.

10. The method of claim 9, comprising: receiving a one-bit indicator from the network node via downlink signaling, the one-bit indicator indicating that a data layer sequence port order corresponds to the non-linear 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, 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 sequences are 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 interference layer 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 interference layer and the downstream interference layer 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 residual interference for the sequence of data layers being zero.

18. The apparatus of claim 14, wherein an antenna port sequence for 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.

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

20. The apparatus of 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.

21. The apparatus of claim 19, comprising: receiving a one-bit indicator from the network node via downlink signaling, the one-bit indicator indicating that a data layer sequence port order corresponds to the non-linear 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, 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.

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 interference layer 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 interference layer and the downstream interference layer 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 an upstream interference layer sequence.

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

29. The method of claim 25, wherein an antenna port sequence for 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.

30. The method of claim 28, wherein the interference suppression comprises using the antenna port sequence to determine at least one interfering data layer sequence for use by the user equipment.

31. The method of 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.

32. The method of claim 31, comprising: transmitting, 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.

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, comprising:

means for 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.

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 interference layer 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 interference layer and the downstream interference layer 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 an upstream interference layer sequence.

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

40. The apparatus of claim 34, wherein an antenna port sequence for 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.

41. The apparatus of claim 39, wherein the interference suppression comprises using the antenna port sequence to determine at least one interfering data layer sequence for use by the user equipment.

42. The apparatus of 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.

43. The apparatus of claim 42, comprising: means for transmitting, 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.

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