EP4285649A1

EP4285649A1 - Transmit power control for multi-relay networks

Info

Publication number: EP4285649A1
Application number: EP21703323.2A
Authority: EP
Inventors: Sharareh KIANI; Shahram SHAHBAZPANAHI; Majid Bavand; Gary Boudreau; Min Dong
Original assignee: Telefonaktiebolaget LM Ericsson AB
Current assignee: Telefonaktiebolaget LM Ericsson AB
Priority date: 2021-01-29
Filing date: 2021-01-29
Publication date: 2023-12-06
Also published as: WO2022162425A1

Abstract

According to some embodiments, a control node for a multi-carrier based system is provided. The multi-carrier system includes a plurality of relay nodes for communicating with a plurality of TR nodes. The control node includes processing circuitry configured to determine a plurality of instances of information related to 5 channel state, determine a transmit power allocation for each of the plurality of TR nodes based at least on the plurality of instances of information, determine respective filter weights for filtering and retransmitting at each of the plurality of relay nodes based at least on the plurality of instances of information, transmit each of the respective filter weights for implementation by the plurality of relay nodes, and 10 transmit at least one transmit power allocation for implementation by at least one of the plurality of TR nodes.

Description

TRANSMIT POWER CONTROL FOR MULTI-RELAY NETWORKS

TECHNICAL FIELD

Wireless communication and in particular, transmit power control in multirelay and multi-carrier networks.

BACKGROUND

In wireless communications, two-way relaying (TWR), also known as bidirectional relaying, provides a higher spectral efficiency than one-way relaying. FIG. 1 is a diagram of a multiple-access broadcast (MABC) method. One protocol for two-way relaying in a MABC system involves all wireless device pairs simultaneously sending their signals to the relay nodes in the multiple access (MA) phase, and then in the broadcast (BC) phase, the relays broadcast a processed version of their received signals toward the wireless device pairs. In other words, information exchange between transceivers of wireless devices is carried out in two time slots. In the first time slot, both transceivers transmit their information symbols towards the relay nodes. In the second time slot, the relay nodes simultaneously broadcast the filtered version of their received signals to other transceivers.

Amplify-and-Forward (AF) and Decode-and-Forward (DF) protocols are known relaying techniques. In the AF method, the relay nodes resend an amplified and phase-shifted version of their received signal from the sender to the receiver, whereas in a DF method, the relays first decode their received signals for checking the errors and then re-encode the signal to retransmit it to the receiver. AF relaying networks have been addressed in the literature for frequency flat channels. However, it is well known that AF-based techniques remain particularly ineffective when it comes to dealing with the inter-symbol interference (ISI) caused at high data rates in frequency-selective channels. For single-carrier transmissions, a filter-and-forward (FF) strategy as an extension of AF strategy can be used to combat the impact of ISI. In FF relaying, each relay is equipped with an FIR or IIR filter and the output of the filter is retransmitted to the wireless device pairs. It is known that FF relaying can significantly surpass AF relaying in performance. Another approach to help cope with ISI is to employ multi-carrier transmission schemes such as OFDM at the wireless devices and/or relay nodes.

However, existing solutions for multi-carrier relay systems either have high computational complexity or poor performance.

SUMMARY

Some embodiments advantageously provide a method and system for transmitting power control in multi-relay and multi-carrier networks.

In one or more embodiments, a half-duplex filter-and-forward (FF) two-way relay system with OFDM transmission is described. Existing systems do not use FF relays* weight design with multi-carrier transmissions in cooperative relay networks. While the FF filter design for OFDM system in relaying networks with a single relay may have been investigated, such a design is not readily transferable to multi-carrier- multi-relay systems due to, for example, ISI and high complexity.

Further, one or more embodiments described herein are configured to minimize the total transmit power subject to quality of service (QoS) constraints, measured by the transceivers* (e.g., wireless devices’) rates. One or more methods (algorithms) described herein advantageously provides a low complexity and fast solution to the power allocation and FIR filtering weights design when compared to existing solutions. One or more embodiments described herein help provide “green”, i.e., energy efficient, communication since they minimize the transmitted electromagnetic power. Additionally, the solution provides a certain quality of service for the transmitters in terms of the transmission rate.

According to one aspect of the disclosure, a control node for a multi-carrier based system is provided. The multi-carrier system includes a plurality of relay nodes for communicating with a plurality of transmit-reception, TR, nodes. The control node includes processing circuitry configured to determine a plurality of instances of information related to channel state where each instance of information is associated with at least one relay node of the plurality of relay nodes and at least one TR node of the plurality of TR nodes, and determine a transmit power allocation for each of the plurality of TR nodes based at least on the plurality of instances of information. The processing circuitry is further configured to determine respective filter weights for filtering and retransmitting at each of the plurality of relay nodes based at least on the plurality of instances of information, transmit each of the respective filter weights for implementation by the plurality of relay nodes, and transmit at least one transmit power allocation for implementation by at least one of the plurality of TR nodes.

According to one or more embodiments, the plurality of TR nodes are a plurality of base stations. According to one or more embodiments, the at least one transmit power allocation includes a plurality of transmit power allocations, each transmit power allocation being communicated to a respective TR node via one of the plurality of relay nodes. According to one or more embodiments, the plurality of relay node are treated as a distributed antenna system.

According to one or more embodiments, the at least one TR node corresponds to a plurality of device-to-device, D2D, enabled wireless device, where the control node corresponds to a base station. According to one or more embodiments, the processing circuitry is further configured to communicate the at least one transmit power allocation to the plurality of D2D enabled wireless devices via a plurality of sidelinks, and communicate the respective filter weights to the plurality of relay nodes one of via the plurality of D2D enabled wireless devices where the node lacks a backhaul link to the plurality of relay nodes. According to one or more embodiments, the processing circuitry is further configured to communicate the at least one transmit power allocation to the plurality of D2D enabled wireless devices via a plurality of sidelinks, and communicate the respective filter weights to the plurality of relay nodes via at least one backhaul link between the control node and the plurality of relay nodes.

According to one or more embodiments, the at least one TR node corresponds to a plurality of device-to-device, D2D, enabled wireless device where the control node corresponds to one of the plurality of D2D enabled wireless devices. According to one or more embodiments, the processing circuitry is further configured to communicate the at least one transmit power allocation to the plurality of D2D enabled wireless devices via a plurality of sidelinks, and communicate the respective filter weights to the plurality of relay nodes via at least one backhaul link between the control node and the plurality of relay nodes. According to one or more embodiments, the plurality of relay nodes provide a D2D sidelink between at least two of the plurality of D2D enabled wireless devices.

According to one or more embodiments, the control node is one of the plurality of TR nodes. According to one or more embodiments, the processing circuitry is further configured to receive channel state information from each of the plurality of relay nodes where the determining of the plurality of instances of information related to channel state is based at least in part on channel state information from each of the plurality of relay nodes. According to one or more embodiments, the at least one TR node corresponds to a plurality of device-to-device (D2D) enabled wireless device where the control node corresponds to a baseband processing unit, BPU.

According to one or more embodiments, the determining of the plurality of instances of information related to channel state includes estimating the channel state of a downlink channel based on at least one uplink transmission. According to one or more embodiments, the determining of the transmit power allocation for each of the plurality of TR nodes and the determining of the respective filter weights is configured to minimize a total transmit power while meeting at least one quality of service constraint.

According to another aspect of the disclosure, a method implemented by a control node for a multi-carrier based system is provided. The multi-carrier system includes a plurality of relay nodes for communicating with a plurality of transmitreception, TR, nodes. A plurality of instances of information related to channel state, is determined where each instance of information is associated with at least one relay node of the plurality of relay nodes and at least one TR node of the plurality of TR nodes. A transmit power allocation for each of the plurality of TR nodes is determined based at least on the plurality of instances of information. Respective filter weights for filtering and retransmitting at each of the plurality of relay nodes is determined based at least on the plurality of instances of information. Each of the respective filter weights for implementation by the plurality of relay nodes is transmitted. At least one transmit power allocation for implementation by at least one of the plurality of TR nodes is transmitted. According to one or more embodiments, the plurality of TR nodes are a plurality of base stations. According to one or more embodiments, the at least one transmit power allocation includes a plurality of transmit power allocations where each transmit power allocation is communicated to a respective TR node via one of the plurality of relay nodes. According to one or more embodiments, the plurality of relay node are treated as a distributed antenna system. According to one or more embodiments, the at least one TR node corresponds to a plurality of device-to-device, D2D, enabled wireless device where the control node corresponds to a base station.

According to one or more embodiments, the at least one transmit power allocation to the plurality of D2D enabled wireless devices is communicated via a plurality of sidelinks. The respective filter weights to the plurality of relay nodes are communicated via the plurality of D2D enabled wireless devices where the control node lacks a backhaul link to the plurality of relay nodes. According to one or more embodiments, the at least one transmit power allocation to the plurality of D2D enabled wireless devices is communicated via a plurality of sidelinks. The respective filter weights to the plurality of relay nodes are communicated via at least one backhaul link between the control node and the plurality of relay nodes. According to one or more embodiments, the at least one TR node corresponds to a plurality of device-to-device, D2D, enabled wireless device, and the control node corresponds to one of the plurality of D2D enabled wireless devices.

According to one or more embodiments, the at least one transmit power allocation to the plurality of D2D enabled wireless devices is communicated via a plurality of sidelinks. The respective filter weights to the plurality of relay nodes are communicated via at least one backhaul link between the control node and the plurality of relay nodes. According to one or more embodiments, the plurality of relay nodes provide a D2D sidelink between at least two of the plurality of D2D enabled wireless devices. According to one or more embodiments, the control node is one of the plurality of TR nodes.

According to one or more embodiments, channel state information is received from each of the plurality of relay nodes where the determining of the plurality of instances of information related to channel state is based at least in part on channel state information from each of the plurality of relay nodes. According to one or more embodiments, the at least one TR node corresponds to a plurality of device-to-device (D2D) enabled wireless device where the control node corresponds to a baseband processing unit, BPU. According to one or more embodiments, the determining of the plurality of instances of information related to channel state includes estimating the channel state of a downlink channel based on at least one uplink transmission. According to one or more embodiments, the determining of the transmit power allocation for each of the plurality of TR nodes and the determining of the respective filter weights is configured to minimize a total transmit power while meeting at least one quality of service constraint.

BRIEF DESCRIPTION OF THE DRAWINGS

A more complete understanding of the present embodiments, and the attendant advantages and features thereof, will be more readily understood by reference to the following detailed description when considered in conjunction with the accompanying drawings wherein:

FIG. 1 is a diagram of a multiple-access broadcast (MABC) system;

FIG. 2 is a schematic diagram of an example network architecture according to the principles in the present disclosure;

FIG. 3 is a block diagram of FIG. 2 according to some embodiments of the present disclosure;

FIG. 4 is a flowchart of an example process in a TR node according to some embodiments of the present disclosure;

FIG. 5 is a flowchart of an example process in a relay node according to some embodiments of the present disclosure;

FIG. 6 is a flowchart of an example process in a control node according to some embodiments of the present disclosure;

FIG. 7 is diagram of a filter-and-forward relay based system;

FIG. 8 is a diagram of system example #1 according to some embodiments of the present disclosure;

FIG. 9 is a diagram of system example #2 according to some embodiments of the present disclosure; FIG. 10 is a diagram of system example #3 according to some embodiments of the present disclosure; and

FIG. 11 is a diagram of system example #4 according to some embodiments of the present disclosure.

DETAILED DESCRIPTION

Before describing in detail example embodiments, it is noted that the embodiments reside primarily in combinations of apparatus components and processing steps related to transmit power control in multi-relay and multi-carrier networks. Accordingly, components have been represented where appropriate by conventional symbols in the drawings, showing only those specific details that are pertinent to understanding the embodiments so as not to obscure the disclosure with details that will be readily apparent to those of ordinary skill in the art having the benefit of the description herein. Like numbers refer to like elements throughout the description.

As used herein, relational terms, such as “first” and “second,” “top” and “bottom,” and the like, may be used solely to distinguish one entity or element from another entity or element without necessarily requiring or implying any physical or logical relationship or order between such entities or elements. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the concepts described herein. As used herein, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises,” “comprising,” “includes” and/or “including” when used herein, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof.

In embodiments described herein, the joining term, “in communication with” and the like, may be used to indicate electrical or data communication, which may be accomplished by physical contact, induction, electromagnetic radiation, radio signaling, infrared signaling or optical signaling, for example. One having ordinary skill in the art will appreciate that multiple components may interoperate and modifications and variations are possible of achieving the electrical and data communication.

In some embodiments described herein, the term “coupled,” “connected,” and the like, may be used herein to indicate a connection, although not necessarily directly, and may include wired and/or wireless connections.

The term “network node” used herein can be any kind of network node comprised in a radio network which may further comprise any of base station (BS), radio base station, base transceiver station (BTS), base station controller (BSC), radio network controller (RNC), g Node B (gNB), evolved Node B (eNB or eNodeB), Node B, multi-standard radio (MSR) radio node such as MSR BS, multi-cell/multicast coordination entity (MCE), integrated access and backhaul (TAB) node, relay node, donor node controlling relay, radio access point (AP), transmission points, transmission nodes, Remote Radio Unit (RRU) Remote Radio Head (RRH), a core network node (e.g., mobile management entity (MME), self-organizing network (SON) node, a coordinating node, positioning node, MDT node, etc.), an external node (e.g., 3rd party node, a node external to the current network), nodes in distributed antenna system (DAS), a spectrum access system (SAS) node, an element management system (EMS), etc. The network node may also comprise test equipment. In some embodiments, “node” may corresponds to a network node or a wireless device, as described herein.

In some embodiments, the non-limiting terms wireless device (WD) or a user equipment (UE) are used interchangeably. The WD herein can be any type of wireless device capable of communicating with a network node or another WD over radio signals, such as wireless device (WD). The WD may also be a radio communication device, target device, device to device (D2D) WD, machine type WD or WD capable of machine to machine communication (M2M), low-cost and/or low-complexity WD, a sensor equipped with WD, Tablet, mobile terminals, smart phone, laptop embedded equipped (LEE), laptop mounted equipment (LME), USB dongles, Customer Premises Equipment (CPE), an Internet of Things (loT) device, or a Narrowband loT (NB-IOT) device, etc. In one or more embodiments, a transceiver (TR) may be a wireless device. Note that although terminology from one particular wireless system, such as, for example, 3GPP LTE and/or New Radio (NR), may be used in this disclosure, this should not be seen as limiting the scope of the disclosure to only the aforementioned system. Other wireless systems, including without limitation Wide Band Code Division Multiple Access (WCDMA), Worldwide Interoperability for Microwave Access (WiMax), Ultra Mobile Broadband (UMB) and Global System for Mobile Communications (GSM), may also benefit from exploiting the ideas covered within this disclosure.

Note further, that functions described herein as being performed by a TR node, control node, relay node, etc., may be distributed over a plurality of one or more of these nodes. In other words, it is contemplated that the functions of TR node, relay node and/or control node described herein are not limited to performance by a single physical device and, in fact, can be distributed among several physical devices.

Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs. It will be further understood that terms used herein should be interpreted as having a meaning that is consistent with their meaning in the context of this specification and the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

Some embodiments provide transmit power control in multi-relay and multicarrier networks.

Referring again to the drawing figures, in which like elements are referred to by like reference numerals, there is shown in FIG. 2 a block diagram of an example communication system 10, which may correspond to one or more of a 3GPP-type cellular network that may support standards such as LTE and/or NR (5G), a device-to- device (D2D) network, etc. System 10 includes a plurality of TR nodes 12a-12n+l (referred to collectively as TR nodes 12). In particular, some embodiments may incorporate two TR nodes 12 while others may incorporate more than two TR nodes 12. Each TR node 12 may communicate with one or more relay nodes 14a- 14n (referred to as relay node 14) via a wireless and/or wired connection, and, in some embodiments, may communicate with control node 16 via a wireless and/or wired connection. System 10 includes one or more relay nodes 14 that are configured to relay transmissions from one or more TR nodes 12. In one or more embodiments, relay node 14 is a filter-and forward (FF) relay node 14 configured to perform OFDM transmission for multi-carrier transmission. System 10, in one or more embodiments, may include control node 16 that is in direct and/or indirect communication with TR node 12 and/or relay node 14.

TR node 12 is configured to include power unit 18 which is configured to perform one or more TR node 12 functions such as with respect to transmit power control in multi-relay and multi-carrier networks, as described herein. Relay node 14 includes relay unit 20 that is configured to perform one or more relay function such as with respect to transmit power control in multi-relay and multi-carrier networks, as described herein. Control node 16 is configured to include configuration unit 22 which is configured to perform one or more control node 16 functions as described herein such as with respect to transmit power control in multi-relay and multi-carrier networks, as described herein.

Example implementations, in accordance with an embodiment, of the TR node 12, relay node 14 and control node 16 discussed in the preceding paragraphs will now be described with reference to FIG. 3. In a communication system 10, a TR node 12 comprises hardware (HW) 24 including a communication interface 26 configured to set up and maintain a wired or wireless connection with an interface of a different communication node of the communication system 10. HW 24 may include radio interface 28 for setting up and maintaining at least a wireless connection with one or more nodes in system 10. The radio interface 28 may be formed as or may include, for example, one or more RF transmitters, one or more RF receivers, and/or one or more RF transceivers.

The TR node 12 further comprises processing circuitry 30, which may have storage and/or processing capabilities. The processing circuitry 30 may include a processor 32 and memory 34. In particular, in addition to or instead of a processor, such as a central processing unit, and memory, the processing circuitry 30 may comprise integrated circuitry for processing and/or control, e.g., one or more processors and/or processor cores and/or FPGAs (Field Programmable Gate Array) and/or ASICs (Application Specific Integrated Circuitry) adapted to execute instructions. The processor 32 may be configured to access (e.g., write to and/or read from) memory 34 which may comprise any kind of volatile and/or nonvolatile memory, e.g., cache and/or buffer memory and/or RAM (Random Access Memory) and/or ROM (Read-Only Memory) and/or optical memory and/or EPROM (Erasable Programmable Read-Only Memory).

Processing circuitry 30 may be configured to control any of the methods and/or processes described herein and/or to cause such methods, and/or processes to be performed, e.g., by TR node 12. Processor 32 corresponds to one or more processors 32 for performing TR node 12 functions described herein. The TR node 12 includes memory 34 that is configured to store data, programmatic software code and/or other information described herein. In some embodiments, the software 36 may include instructions that, when executed by the processor 32 and/or processing circuitry 30, causes the processor 32 and/or processing circuitry 30 to perform the processes described herein with respect to TR node 12. The processing circuitry 30 of the TR node 12 may include a power unit 18 that is configured to perform one or more TR node 12 functions as described herein such as with respect to transmit power control in multi-relay and multi-carrier networks, as described herein.

The system 10 further includes a relay node 14 where relay node 14 includes hardware 38 enabling it to communicate with TR node 12 and/or control node 16. The hardware 38 may include a communication interface 40 for setting up and maintaining a wired or wireless connection with an interface of a different communication node of the communication system 10, as well as a radio interface 42 for setting up and using at least a wireless connection with one or more nodes such as with TR node 12 and/or control node 16. The radio interface 42 may be formed as or may include, for example, one or more RF transmitters, one or more RF receivers, and/or one or more RF transceivers.

In the embodiment shown, the hardware 38 of the relay node 14 further includes processing circuitry 44. The processing circuitry 44 may include a processor 46 and a memory 48. In particular, in addition to or instead of a processor, such as a central processing unit, and memory, the processing circuitry 44 may comprise integrated circuitry for processing and/or control, e.g., one or more processors and/or processor cores and/or FPGAs (Field Programmable Gate Array) and/or ASICs (Application Specific Integrated Circuitry) adapted to execute instructions. The processor 46 may be configured to access (e.g., write to and/or read from) the memory 48, which may comprise any kind of volatile and/or nonvolatile memory, e.g., cache and/or buffer memory and/or RAM (Random Access Memory) and/or ROM (Read-Only Memory) and/or optical memory and/or EPROM (Erasable Programmable Read-Only Memory).

Thus, the relay node 14 further has software 50 stored internally in, for example, memory 48, or stored in external memory (e.g., database, storage array, network storage device, etc.) accessible by the relay node 14 via an external connection. The software 50 may be executable by the processing circuitry 44. The processing circuitry 44 may be configured to control any of the methods and/or processes described herein and/or to cause such methods, and/or processes to be performed, e.g., by relay node 14. Processor 46 corresponds to one or more processors 46 for performing relay node 14 functions described herein. The memory 48 is configured to store data, programmatic software code and/or other information described herein. In some embodiments, the software 50 may include instructions that, when executed by the processor 46 and/or processing circuitry 44, causes the processor 46 and/or processing circuitry 44 to perform the processes described herein with respect to relay node 14. For example, processing circuitry 44 of the relay node 14 may include relay unit 20 configured to perform one or more relay node 14 functions as described herein such as with respect to transmit power control in multirelay and multi-carrier networks, as described herein.

The communication system 10 further includes the control node 16 already referred to. The control node 16 may have hardware 52 that may include a communication interface 54 for setting up and maintaining a wired or wireless connection with an interface of a different communication node of the communication system 10, as well as a radio interface 56 for setting up and using at least a wireless connection with one or more nodes such as with TR node 12 and/or relay node 14. The radio interface 56 may be formed as or may include, for example, one or more RE transmitters, one or more RF receivers, and/or one or more RF transceivers.

The hardware 52 of the control node 16 further includes processing circuitry 58. The processing circuitry 58 may include a processor 60 and memory 62. In particular, in addition to or instead of a processor, such as a central processing unit, and memory, the processing circuitry 58 may comprise integrated circuitry for processing and/or control, e.g., one or more processors and/or processor cores and/or FPGAs (Field Programmable Gate Array) and/or ASICs (Application Specific Integrated Circuitry) adapted to execute instructions. The processor 60 may be configured to access (e.g., write to and/or read from) memory 62, which may comprise any kind of volatile and/or nonvolatile memory, e.g., cache and/or buffer memory and/or RAM (Random Access Memory) and/or ROM (Read-Only Memory) and/or optical memory and/or EPROM (Erasable Programmable Read-Only Memory).

Thus, the control node 16 may further comprise software 64, which is stored in, for example, memory 62 at control node 16, or stored in external memory (e.g., database, storage array, network storage device, etc.) accessible by control node 16. The software 64 may be executable by the processing circuitry 58. The processing circuitry 58 may be configured to control any of the methods and/or processes described herein and/or to cause such methods, and/or processes to be performed, e.g., by control node 16. The processor 60 corresponds to one or more processors 60 for performing control node 16 functions described herein. The control node 16 includes memory 62 that is configured to store data, programmatic software code and/or other information described herein. In some embodiments, the software 64 may include instructions that, when executed by the processor 60 and/or processing circuitry 58, causes the processor 60 and/or processing circuitry 58 to perform the processes described herein with respect to control node 16. For example, the processing circuitry 58 of the control node 16 may include a configuration unit 22 configured to perform one or more control node 16 function as described herein such as with respect to transmit power control in multi-relay and multi-carrier networks, as described herein.

In some embodiments, the inner workings of the TR node 12, relay node 14 and control node 16 may be as shown in FIG. 3 and independently, the surrounding network topology may be that of FIG. 2.

Although FIGS. 2 and 3 show various “units” such as power unit 18, relay unit 20 and configuration unit 22 as being within a respective processor, it is contemplated that these units may be implemented such that a portion of the unit is stored in a corresponding memory within the processing circuitry. In other words, the units may be implemented in hardware or in a combination of hardware and software within the processing circuitry.

FIG. 4 is a flowchart of an example process in TR node 12 according to some embodiments of the present disclosure. One or more Blocks and/or functions performed by TR node 12 may be performed by one or more elements of TR node 12 such as by power unit 18 in processing circuitry 30, processor 32, radio interface 28, etc. In one or more embodiments, TR node 12 such as via one or more of processing circuitry 30, processor 32, power unit 18, communication interface 26 and radio interface 28 is configured to receive (Block S 100) a transmission power allocation that is based at least in part on a plurality of instances of information related to channel state, as described herein. In one or more embodiments, TR node 12 such as via one or more of processing circuitry 30, processor 32, power unit 18, communication interface 26 and radio interface 28 is configured to implement (Block S102) the transmission power allocation for communication, as described herein.

FIG. 5 is a flowchart of an example process in relay node 14 according to some embodiments of the present disclosure. One or more Blocks and/or functions performed by relay node 14 may be performed by one or more elements of relay node 14 such as by relay unit 20 in processing circuitry 44, processor 46, radio interface 42, etc. In one or more embodiments, relay node 14 such as via one or more of processing circuitry 44, processor 46, relay unit 20, communication interface 40 and radio interface 42 is configured to receive (Block S104) a filter weights for transmission where the filter weights are based at least in part on a plurality of instances of information related to channel state, as described herein. In one or more embodiments, relay node 14 such as via one or more of processing circuitry 44, processor 46, relay unit 20, communication interface 40 and radio interface 42 is configured to implement (Block S 106) the filter weights for communication, as described herein.

FIG. 6 is a flowchart of an example process in a control node 16 according to one or more embodiments of the disclosure. One or more Blocks and/or functions performed by control node 16 may be performed by one or more elements of control node 16 such as by configuration unit 22 in processing circuitry 58, processor 60, radio interface 56, etc. In one or more embodiments, control node 16 such as via one or more of processing circuitry 58, processor 60, configuration unit 22, communication interface 54 and radio interface 56 is configured to determine (Block S108) a plurality of instances of information related to channel state where each instance of information is associated with at least one relay node 14 of the plurality of relay nodes 14 and at least one TR node 12 of the plurality of TR nodes 12, as described herein. In one or more embodiments, control node 16 such as via one or more of processing circuitry 58, processor 60, configuration unit 22, communication interface 54 and radio interface 56 is configured to determine (Block S 110) a transmit power allocation for each of the plurality of TR nodes 12 based at least on the plurality of instances of information, as described herein.

In one or more embodiments, control node 16 such as via one or more of processing circuitry 58, processor 60, configuration unit 22, communication interface 54 and radio interface 56 is configured to determine (Block S 112) respective filter weights for filtering and retransmitting at each of the plurality of relay nodes 14 based at least on the plurality of instances of information, as described herein. In one or more embodiments, control node 16 such as via one or more of processing circuitry 58, processor 60, configuration unit 22, communication interface 54 and radio interface 56 is configured to transmit (Block S 114) each of the respective filter weights for implementation by the plurality of relay nodes 14, as described herein. In one or more embodiments, control node 16 such as via one or more of processing circuitry 58, processor 60, configuration unit 22, communication interface 54 and radio interface 56 is configured to transmit (Block SI 16) at least one transmit power allocation for implementation by at least one of the plurality of TR nodes 12, as described herein.

According to one or more embodiments, the plurality of TR nodes 12 are a plurality of base stations. According to one or more embodiments, the at least one transmit power allocation includes a plurality of transmit power allocations, each transmit power allocation being communicated to a respective TR node 12 via one of the plurality of relay nodes 14. According to one or more embodiments, the plurality of relay node 14 are treated as a distributed antenna system (DAS). According to one or more embodiments, the at least one TR node 12 corresponds to a plurality of device-to-device, D2D, enabled wireless device, where the control node 16 correspond to a base station. According to one or more embodiments, the processing circuitry 58 is further configured to: communicate the at least one transmit power allocation to the plurality of D2D enabled wireless devices via a plurality of sidelinks, and communicate the respective filter weights to the plurality of relay nodes 14 one of via the plurality of D2D enabled wireless devices. The control node 16 lacks a backhaul link to the plurality of relay nodes 14. According to one or more embodiments, the processing circuitry 58 is further configured to communicate the at least one transmit power allocation to the plurality of D2D enabled wireless devices via a plurality of sidelinks, and communicate the respective filter weights to the plurality of relay nodes 14 via at least one backhaul link between the node and the plurality of relay nodes 14.

According to one or more embodiments, the at least one TR node 12 corresponds to a plurality of device-to-device, D2D, enabled wireless device, and the control node 16 corresponds to one of the plurality of D2D enabled wireless devices. According to one or more embodiments, the processing circuitry 58 is further configured to communicate the at least one transmit power allocation to the plurality of D2D enabled wireless devices via a plurality of sidelinks, and communicate the respective filter weights to the plurality of relay nodes 14 via at least one backhaul link between the control node 16 and the plurality of relay nodes 14. According to one or more embodiments, the plurality of relay nodes 14 provide a D2D sidelink between at least two of the plurality of D2D enabled wireless devices.

According to one or more embodiments, the control node 16 is one of the plurality of TR nodes 12. According to one or more embodiments, the processing circuitry 58 is further configured to receive channel state information from each of the plurality of relay nodes 14 where the determining of the plurality of instances of information related to channel state is based at least in part on channel state information from each of the plurality of relay nodes 14. According to one or more embodiments, the at least one TR node 12 corresponds to a plurality of device-to- device (D2D) enabled wireless device where the node corresponds to a baseband processing unit, BPU. According to one or more embodiments, the determining of the plurality of instances of information related to channel state includes estimating the channel state of a downlink channel based on at least one uplink transmission. According to one or more embodiments, the determining of the transmit power allocation for each of the plurality of TR nodes 12 and the determining of the respective filter weights is configured to minimize a total transmit power while meeting at least one quality of service constraint.

Having generally described arrangements for transmission power control in multi-relay and multi-carrier networks, details for these arrangements, functions and processes are provided as follows, and which may be implemented by the control node 16, relay node 14 and/or TR node 12. One or more functions described below as being performed by TR node 12 may be performed via one or more of processing circuitry 30, processor 32, radio interface 28, power unit 18, etc., which are elements of TR node 12 that are defined above. One or more functions described below as being performed by relay node 14 may be performed via one or more of processing circuitry 44, processor 46, radio interface 42, relay unit 20, etc., which are elements of relay node 14 that are defined above. One or more functions described below as being performed by control node 16 may be performed via one or more of processing circuitry 58, processor 60, radio interface 56, configuration unit 22, etc., which are elements of control node 16 that are defined above. One example of a two-way FF relaying system is illustrated in FIG. 7. The system includes one or more of the following characteristics:

• No direct link between transceivers

• Frequency selective channel model with L taps

• OFDM transceivers with N subcarriers

• FIR filters (equalizers) with L_w taps

• CSI knowledge

• Channel reciprocity

One or more embodiments described herein are directed to minimizing the total transmit power subject to quality of service (QoS) constraints on transceivers' (i.e., TR nodes) rates in a two-way asynchronous network including two OFDM- based transceivers and multiple FF relays. The total transmit power may be defined as the average transmit power over all the OFDM subcarriers at both transceivers plus the total average transmit power at the relays.

System Example #1: network node and relays

FIG. 8 is a block diagram of an example system according to one or more embodiments of the disclosure. In FIG. 8, TR node 12a and TR node 12b may be considered as two network nodes with no direct line of sight (LOS) communication link between each other and relay nodes 14 can be assumed as auxiliary relay nodes of the network. If it is required for these two TR nodes 12 (e.g., base stations) to have an interface (X2 interface in LTE, Xn interface in NR), it can be implemented by a wired connection such as a cable or other equivalent technology. However, if a wired connection is not available, the NR nodes 12 may communicate with each other via a two-way-relaying network. Channel state information between a relay and each TR node 12 can be transmitted from the relay node 14 to a centralized processing unit (CPU), i.e., control node 16, possibly through a backhaul link. Control node 16 evaluates the power allocation of the transceivers (TR nodes 12) and the filter weights at each relay node 14 and conveys this information to the relay nodes 14 via backhaul link. Additionally, relay nodes 14 are configured to inform the TR nodes 12 on their power allocation. In other words, in one or more embodiments, relay nodes 14 append the power allocation information to the original information. Note that TR nodes 12 and relay nodes 14 are not moving and hence the channel between them will experience slow fading. As an alternate instantiation of this embodiment, control node 16 could also communicate directly with the TR node 12a and TR node 12b to inform them of their power and antenna weight allocations.

System embodiment # 2: Device-to-Device (D2D) TR nodes 12 with Relay nodes 14

FIG. 9 is a block diagram of another example system according to one or more embodiments of the disclosure. The configuration for system example #2 includes D2D communications of TR nodes 12 with relay nodes 14 where the TR nodes 12 are D2D enabled wireless devices. In this embodiment, the relay network acts as a D2D sidelink between two D2D enabled wireless devices (i.e., TR nodes 12), with the control of the sidelink relay network being supported by control node 16 which may be a controlling or serving network node such as an eNB. Configuration of the relay nodes 14 and calculation of the optimal power settings in the relay nodes 14, and TR nodes 12s (i.e., D2D devices in this example) can be implemented in either control node 16 or one or more TR nodes 12, as detailed below: a) Control node 16 supported optimization: Channel state information between a relay node 14 and each TR node 12 (i.e., D2D transceiver) is transmitted from the relay node 14 to a centralized processing unit (CPU) (i.e., processing circuitry 58) in the control node 16 (i.e., controlling eNB), through either i. a backhaul to the relay nodes 14 and a sidelink to the TR nodes 12 (i.e., D2D devices). In this configuration the control node 16 evaluates the power allocation of the TR nodes 12 and the filter weights for each relay node 14 (i.e., D2D node/wireless device) and conveys this information to the corresponding relay node 14 through the backhaul link, and to the TR nodes 12 (i.e., D2D nodes) through the sidelink; or ii. Both the relay node 14 signaling and TR node 12 signaling is transmitted to the control node 16 (i.e., serving eNB) through the D2D sidelink. In this configuration, the relay nodes 14 only communicate to the TR nodes 12 (i.e., D2D devices) and do not have a backhaul link to the control node 16 (i.e., serving eNB). Control node 16 evaluates the power allocation of the TR nodes 12 and the filter weights for each relay node 14 and conveys/transmits this information to the respective relay node 14 via the D2D sidelink and the corresponding TR node 12 to relay signaling channel. In addition, control node 16 may calculate the TR node 12 power configuration and convey/transmit this information to the TR node 12. b) TR node 12 (i.e., D2D node/wireless device) supported optimization: Channel state information between a relay node 14 and each TR node 12 is transmitted from the relay node 14 such as via communication interface 40 and/or radio interface 42 to a centralized processing unit (CPU) in a controlling TR node 12 (i.e., controlling D2D node). The controlling TR node 12 evaluates the power allocation of the TR nodes 12 (including, for example, itself) and the filter weights at each relay node 14 and conveys this information to the corresponding relay node 14, through the TR node 12-to-relay node 14 channel. In this configuration, the power and antenna weight optimizations for the noncontrolling TR nodes 12 (i.e., non-controlling D2D node(s) or other TR nodes 12 can be communicated to them either through the control node 16 (acting as a serving eNB) via the sidelink channels, or through a message from the controlling TR node 12 to the non-controlling TR nodes 12 via the relay channels.

System embodiment # 3: D2D configured as DAS

In another example, TR nodes 12 are D2D nodes and relay nodes 14 are considered as a distributed antenna systems (DAS) as illustrated in FIG. 10. TR node 12a and TR node 12b can be considered two wireless devices that communicate with each other within the network; furthermore, each relay node 14 can be represented as an equivalent antenna element of a DAS system. Transmission between TR node 12a and TR node 12b can be assumed to be over a full-duplex connection that is realized via half-duplex communication between devices (TR nodes 12) and DAS (relay nodes 14) together with half-duplex communication between DAS and devices.

Furthermore, it is assumed that the DAS (i.e., relay nodes 14) is connected via fronthaul to a baseband processing unit (BPU) provided by control node 16. When it is known to control node 16 that TR node 12a and TR node 12b have requested to communicate with each other, control node 16 (i.e., BPU in this example) can coschedule their UL transmissions. Similarly, DL transmission of TR node 12a and TR node 12b can also be co-scheduled at the same time and frequency resources. This is to some extent similar to transmission of multiple wireless devices in MU-MIMO communication.

Assuming transmission reciprocity, the channel state of DL can be estimated, at control node 16, from the UL transmission. For each relay node 14, control node 16 then calculates the filtering weights of the next DL transmission without decoding each TR node 12’s data (except for decoding the pilots (i.e., pilot signals) of each TR node 12 for channel estimation). Control node 16 (i.e., BPU in this example) also calculates the UL power of each TR node 12 for the next UL transmission and signals this information to each TR node 12 in a DL control information message.

Additionally, to improve the general power consumption of DAS elements, an adaptive antenna selection algorithm may be used for both DL and UL transmission in two-way relaying. For example, for DL transmissions, a set of DAS elements that minimize the pathlosses from both TR nodes 12 may be pre-selected by control node 16. It is noted that any antenna preselection scheme may further reduce optimality of the algorithms described herein for total transmit power minimization, as the antenna preselection scheme would reduce total power consumption of DAS and computation cost/energy in control node 16. As another example, assume that there are N DAS elements where each DAS element may be, for example a relay node 14. Out of N DAS elements, a pool of N1 elements may be selected where the received powers from both TR node 12a and TR node 12b are greater than a threshold. In the allocated slots, control node 16 selects a smaller pool of N2 DAS elements (N2<N1<N) for both DL and UL transmissions, either by i) randomly selecting N2 elements or ii) selecting N2 elements with the largest sum of received power from both TR node 12a and TR 12b pilots over all subcarriers (less path loss and larger channel gains). Other criteria for selection of the N2 DAS elements can be employed including the DAS elements with the largest SINR, and/or largest SLNR, for example.

System Example # 4: multi TR node 12 transmission

The system configuration for system example #4 includes multi-TR node 12 transmission as illustrated in FIG. 11. In this example, there can be up to “n” transmitting TR nodes 12 (i.e., TR nodes 12a- 12n) in the network and one receiving TR node 12 (i.e., TR node n+1), with the “n” transmitting TR nodes 12 communicating with the one receiving TR node 12n+l via the relay network (i.e., via one or more relay nodes 14). The transmissions from the ‘n* transmitting TR nodes 12 are assumed to support a CoMP (coordinated multi-point) transmission of the same data. Power and beamforming optimization of the relay nodes 14 can be supported by a controlling TR node 12 which may act as or corresponds to control node 16, which may be, for example, TR node 12a without loss of generality. For example, TR node 12a may include configuration unit 22 for performing one or more control node 16 functions.

In a first configuration, the controlling TR node 12a such as via one or more of processing circuitry 30, processor 32, radio interface 28, configuration unit 22 (implemented in TR node 12a), etc., may calculate the power and beamforming weights for transmissions between all transmitting TR nodes 12 (i.e., TR nodes 12a- 12n) and all relay nodes 14, as well as the transmissions between the relay nodes 14 and the receiving TR node 12 (i.e., TR node 12n+l). In this configuration, channel state information between a relay node 14 and the controlling TR node 12 (i.e., acting as control node 16) is transmitted from the relay node 14 to a centralized processing unit (CPU) in the controlling TR node 12, possibly through a backhaul link. The controlling TR node 12 (which as acting as well as control node 16) such as via one or more of processing circuitry 30, processor 32, radio interface 28, configuration unit 22 (implemented in TR node 12), etc., evaluates the power allocation of the TR nodes 12 and the filter weights at each relay node 14 and conveys this information to the corresponding relay node 14, possibly through a backhaul link. Furthermore, since the controlling TR node 12 is also calculating the power and beamforming weights of all of the other transmitting TR nodes 12, the controlling TR node 12 may receive channel state information from the other transmitting TR nodes 12, possibly through an X2 or equivalent link TR node 12-to-TR node 12 link, and transmit the optimized power and beamforming weights to the other TR nodes 12 possibly through an X2 or equivalent TR node 12-to-TR node 12 link.

In a second configuration, the controlling TR node 12 such as via one or more of processing circuitry 30, processor 32, radio interface 28, configuration unit 22 (implemented in TR node 12), etc., calculates the power and beamforming weights for the transmissions between itself and the relay node 14 to receiving TR node 12 transmissions. The calculation of the power and beamforming weights for the transmissions between the other transmitting TR nodes 12 and the relay nodes 14 may be calculated in a distributed manner at each of the transmitting TR node 12 and communicated to the respective relay nodes 14. Note that since the processing is distributed, this configuration may not produce a global optimization of the minimization of the transmit powers, however it provides a lower complexity solution to the problem.

Two methods are defined to solve the joint optimization of the power allocation and FF relay weight design in TWR network with transceivers (i.e., TR nodes 12) and multiple FF relay nodes 14 as defined in equation (1) below. These methods may be implemented in the OFDM transceivers, i.e., at the TR nodes 12, which may include a network node such as an eNB or gNB for 3GPP implementations or wireless transceiver nodes (i.e., TR nodes 12) employing other technologies.

(Equation 1)

One solution to this optimization problem may be found through exhaustive search with impractically high computational complexity. However, the present disclosure describes two reduced complexity sub-opthnal methods that solve the problem. These methods can be implemented in any one of the system examples described above.

Method #1: Waterfilling Method

This method solves the original problem and can be proven to converge to a local minimizer of the problem as explained below:

Equation 35, i.e., (35), is defined as follows: where γ₂ is the corresponding Lagrange multiplier.

Method #2: Frequency Flat Estimation Approach

In this method, the problem is simplified by making an additional assumption that end-to-end channel can be approximated as a flat amplitude channel. Adding this new constraint to the original optimization problem, it can be solved as described in the following algorithm:

Equation 7 is defined as follows: (7)

Equation 21 is defined as follows:

(21)

5 where e_R,r is the r-th column of the identify matrix I_r, K_j represents (RL_w)x (L+L_w -1) matrix defined as and the RL_wxRL_w permutation matrix II as

(22) where the following is defined: where denotes a Kronecker product operati on, and is the l-th columns of the identity matrix

Equation 66 is defined as follow:

(66)

Equation 68 is defined as follows:

(68)

Regarding Equation 89: to obtain matrix C_n, the L_nz-1 independent columns of matrix corresponding to wl may need to be captured. Given the block Teoplitz structure of matrix , there exists a permutation matrix such that

(89) where is a full rank matrix (rank(C_1,n) = L_nz - 1) which captures the first L_nz-1 columns of the matrix holds the rest of the columns in is obtained such that those L_nz-1 columns of the matrix B-_n which result in a full rank low condition number square matrix will be reordered as the first L_nz-1 columns of the matrix

Note, regarding Algorithms 1 and 2, other equations such as equations (2), (31), (81), etc., have been omitted for clarity purposes.

As will be appreciated by one of skill in the art, the concepts described herein may be embodied as a method, data processing system, computer program product and/or computer storage media storing an executable computer program. Accordingly, the concepts described herein may take the form of an entirely hardware embodiment, an entirely software embodiment or an embodiment combining software and hardware aspects all generally referred to herein as a “circuit” or “module.” Any process, step, action and/or functionality described herein may be performed by, and/or associated to, a corresponding module, which may be implemented in software and/or firmware and/or hardware. Furthermore, the disclosure may take the form of a computer program product on a tangible computer usable storage medium having computer program code embodied in the medium that can be executed by a computer. Any suitable tangible computer readable medium may be utilized including hard disks, CD-ROMs, electronic storage devices, optical storage devices, or magnetic storage devices.

Some embodiments are described herein with reference to flowchart illustrations and/or block diagrams of methods, systems and computer program products. It will be understood that each block of the flowchart illustrations and/or block diagrams, and combinations of blocks in the flowchart illustrations and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer (to thereby create a special purpose computer), special purpose computer, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions/acts specified in the flowchart and/or block diagram block or blocks.

These computer program instructions may also be stored in a computer readable memory or storage medium that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer readable memory produce an article of manufacture including instruction means which implement the function/act specified in the flowchart and/or block diagram block or blocks.

The computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions/acts specified in the flowchart and/or block diagram block or blocks.

It is to be understood that the functions/acts noted in the blocks may occur out of the order noted in the operational illustrations. For example, two blocks shown in succession may in fact be executed substantially concurrently or the blocks may sometimes be executed in the reverse order, depending upon the fiinctionality/acts involved. Although some of the diagrams include arrows on communication paths to show a primary direction of communication, it is to be understood that communication may occur in the opposite direction to the depicted arrows.

Computer program code for carrying out operations of the concepts described herein may be written in an object oriented programming language such as Java® or C++. However, the computer program code for carrying out operations of the disclosure may also be written in conventional procedural programming languages, such as the "C" programming language. The program code may execute entirely on the user's computer, partly on the user's computer, as a stand-alone software package, partly on the user's computer and partly on a remote computer or entirely on the remote computer. In the latter scenario, the remote computer may be connected to the user's computer through a local area network (LAN) or a wide area network (WAN), or the connection may be made to an external computer (for example, through the Internet using an Internet Service Provider).

Many different embodiments have been disclosed herein, in connection with the above description and the drawings. It will be understood that it would be unduly repetitious and obfuscating to literally describe and illustrate every combination and subcombination of these embodiments. Accordingly, all embodiments can be combined in any way and/or combination, and the present specification, including the drawings, shall be construed to constitute a complete written description of all combinations and subcombinations of the embodiments described herein, and of the manner and process of making and using them, and shall support claims to any such combination or subcombination.

Abbreviations that may be used in the preceding description include:

Abbreviation Explanation

AAS Active Antenna System

BBU Baseband Unit

CSI-RS Channel State Information Reference Signal

DPT Discrete Fourier Transform

DMRS Demodulation Reference Signal FD-MIMO Full Dimension MIMO

FF Filter and forward

GoB Grid-of-beams

MABC Multiple Access Broadcast

PMI Precoding Matrix Indicator

RRH Remote Radio Head

TWR Two way relaying

It will be appreciated by persons skilled in the art that the embodiments described herein are not limited to what has been particularly shown and described herein above. In addition, unless mention was made above to the contrary, it should be noted that all of the accompanying drawings are not to scale. A variety of modifications and variations are possible in light of the above teachings without departing from the scope of the following claims.

Claims

What is claimed is:

1. A control node (16) for a multi-carrier system, the multi-carrier system including a plurality of relay nodes (14) for communicating with a plurality of transmit-reception, TR, nodes (12), the control node (16) comprising: processing circuitry (58) configured to: determine a plurality of instances of information related to channel state, each instance of information being associated with at least one relay node (14) of the plurality of relay nodes (14) and at least one TR node (12) of the plurality of TR nodes (12); determine a transmit power allocation for each of the plurality of TR nodes (12) based at least on the plurality of instances of information; determine respective filter weights for filtering and retransmitting at each of the plurality of relay nodes (14) based at least on the plurality of instances of information; transmit each of the respective filter weights for implementation by the plurality of relay nodes (14); and transmit at least one transmit power allocation for implementation by at least one of the plurality of TR nodes (12).

2. The control node (16) of Claim 1, wherein the plurality of TR nodes (12) are a plurality of base stations.

3. The control node (16) of any one of Claims 1-2, wherein the at least one transmit power allocation includes a plurality of transmit power allocations, each transmit power allocation being communicated to a respective TR node (12) via one of the plurality of relay nodes (14).

4. The control node (16) of any one of Claims 1-3, wherein the plurality of relay nodes (14) are treated as a distributed antenna system.

5. The control node (16) of Claim 1, wherein the at least one TR node

(12) corresponds to a plurality of device-to-device, D2D, enabled wireless device; and the control node (16) corresponds to a base station.

6. The control node (16) of Claims 5, wherein the processing circuitry

(58) is further configured to: communicate the at least one transmit power allocation to the plurality of D2D enabled wireless devices via a plurality of sidelinks; and communicate the respective filter weights to the plurality of relay nodes (14) via the plurality of D2D enabled wireless devices, the node lacking a backhaul link to the plurality of relay nodes (14).

7. The control node (16) of Claims 5, wherein the processing circuitry

(58) is further configured to: communicate the at least one transmit power allocation to the plurality of D2D enabled wireless devices via a plurality of sidelinks; and communicate the respective filter weights to the plurality of relay nodes (14) via at least one backhaul link between the control node (16) and the plurality of relay nodes (14).

8. The control node (16) of Claim 1, wherein the at least one TR node

(12) corresponds to a plurality of device-to-device, D2D, enabled wireless device; and the control node (16) corresponds to one of the plurality of D2D enabled wireless devices.

9. The control node (16) of Claim 8, wherein the processing circuitry (58) is further configured to: communicate the at least one transmit power allocation to the plurality of D2D enabled wireless devices via a plurality of sidelinks; and communicate the respective filter weights to the plurality of relay nodes (14) via at least one backhaul link between the control node (16) and the plurality of relay nodes (14).

10. The control node (16) of any one of Claims 5-9, wherein the plurality of relay nodes (14) provide a D2D sidelink between at least two of the plurality of D2D enabled wireless devices.

11. The control node (16) of Claim 1, wherein the control node (16) is one of the plurality of TR nodes (12).

12. The control node (16) of any one of Claims 1-11, wherein the processing circuitry (58) is further configured to receive channel state information from each of the plurality of relay nodes (14), the determining of the plurality of instances of information related to channel state being based at least in part on channel state information from each of the plurality of relay nodes (14).

13. The control node (16) of Claim 11, wherein the determining of the plurality of instances of information related to channel state includes estimating the channel state of a downlink channel based on at least one uplink transmission.

14. The control node (16) of Claim 1, wherein the at least one TR node (12) corresponds to a plurality of device-to-device (D2D) enabled wireless device; and the control node (16) corresponds to a baseband processing unit, BPU.

15. The control node (16) of any one of Claims 1-14, wherein the determining of the transmit power allocation for each of the plurality of TR nodes (12) and the determining of the respective filter weights is configured to minimize a total transmit power while meeting at least one quality of service constraint.

16. A method implemented by a control node (16) for a multi-carrier based system, the multi-carrier system including a plurality of relay nodes (14) for communicating with a plurality of transmit-reception, TR, nodes (16), the method comprising: determining (S108) a plurality of instances of information related to channel state, each instance of information being associated with at least one relay node (14) of the plurality of relay nodes (14) and at least one TR node (12) of the plurality of TR nodes (12); determining (S 110) a transmit power allocation for each of the plurality of TR nodes (12) based at least on the plurality of instances of information; determining (S 112) respective filter weights for filtering and retransmitting at each of the plurality of relay nodes (14) based at least on the plurality of instances of information; transmitting (S 114) each of the respective filter weights for implementation by the plurality of relay nodes (14); and transmitting (S 116) at least one transmit power allocation for implementation by at least one of the plurality of TR nodes (12).

17. The method of Claim 16, wherein the plurality of TR nodes (12) are a plurality of base stations.

18. The method of any one of Claims 16-17, wherein the at least one transmit power allocation includes a plurality of transmit power allocations, each transmit power allocation being communicated to a respective TR node (12) via one of the plurality of relay nodes (14).

19. The method of any one of Claims 16-18, wherein the plurality of relay node (14) are treated as a distributed antenna system.

20. The method of Claim 16, wherein the at least one TR node (12) corresponds to a plurality of device-to-device, D2D, enabled wireless device; and the control node (16) corresponds to a base station.

21. The method of Claim 20, further comprising: communicating the at least one transmit power allocation to the plurality of D2D enabled wireless devices via a plurality of sidelinks; and communicating the respective filter weights to the plurality of relay nodes (14) one of via the plurality of D2D enabled wireless devices, the control node (16) lacking a backhaul link to the plurality of relay nodes (14).

22. The method of Claim 20, further comprising: communicating the at least one transmit power allocation to the plurality of D2D enabled wireless devices via a plurality of sidelinks; and communicating the respective filter weights to the plurality of relay nodes (14) via at least one backhaul link between the control node (16) and the plurality of relay nodes (14).

23. The method of Claim 16, wherein the at least one TR node (12) corresponds to a plurality of device-to-device, D2D, enabled wireless device; and the control node (16) corresponds to one of the plurality of D2D enabled wireless devices.

24. The method of Claim 23, further comprising: communicating the at least one transmit power allocation to the plurality of D2D enabled wireless devices via a plurality of sidelinks; and communicating the respective filter weights to the plurality of relay nodes (14) via at least one backhaul link between the control node (16) and the plurality of relay nodes (14).

25. The method of any one of Claims 20-24, wherein the plurality of relay nodes (14) provide a D2D sidelink between at least two of the plurality of D2D enabled wireless devices.

26. The method of Claim 16, wherein the control node is one of the plurality of TR nodes (12).

27. The method of any one of Claims 16-26, further comprising receiving channel state information from each of the plurality of relay nodes (14), the determining of the plurality of instances of information related to channel state being based at least in part on channel state information from each of the plurality of relay nodes (14).

28. The method of Claim 26, wherein the determining of the plurality of instances of information related to channel state includes estimating the channel state of a downlink channel based on at least one uplink transmission.

29. The method of Claim 16, wherein the at least one TR node (12) corresponds to a plurality of device-to-device (D2D) enabled wireless device; and the control node corresponds to a baseband processing unit, BPU.

30. The method of any one of Claims 16-29, wherein the determining of the transmit power allocation for each of the plurality of TR nodes (12) and the determining of the respective filter weights is configured to minimize a total transmit power while meeting at least one quality of service constraint.