CN106374987B - Full-duplex relay combined target-relay-antenna selection method - Google Patents

Full-duplex relay combined target-relay-antenna selection method Download PDF

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CN106374987B
CN106374987B CN201610768069.8A CN201610768069A CN106374987B CN 106374987 B CN106374987 B CN 106374987B CN 201610768069 A CN201610768069 A CN 201610768069A CN 106374987 B CN106374987 B CN 106374987B
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CN106374987A (en
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高晖
吕铁军
汤亚南
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Beijing University of Posts and Telecommunications
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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B7/00—Radio transmission systems, i.e. using radiation field
    • H04B7/02—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas
    • H04B7/04—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas
    • H04B7/06—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the transmitting station
    • H04B7/0602—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the transmitting station using antenna switching
    • H04B7/0608—Antenna selection according to transmission parameters
    • H04B7/061—Antenna selection according to transmission parameters using feedback from receiving side
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B7/00—Radio transmission systems, i.e. using radiation field
    • H04B7/02—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas
    • H04B7/022—Site diversity; Macro-diversity
    • H04B7/026—Co-operative diversity, e.g. using fixed or mobile stations as relays
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B7/00—Radio transmission systems, i.e. using radiation field
    • H04B7/02—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas
    • H04B7/04—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas
    • H04B7/0413—MIMO systems
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B7/00—Radio transmission systems, i.e. using radiation field
    • H04B7/02—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas
    • H04B7/04—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas
    • H04B7/06—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the transmitting station
    • H04B7/0613—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the transmitting station using simultaneous transmission
    • H04B7/0615—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the transmitting station using simultaneous transmission of weighted versions of same signal
    • H04B7/0619—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the transmitting station using simultaneous transmission of weighted versions of same signal using feedback from receiving side
    • H04B7/0621—Feedback content
    • H04B7/0626—Channel coefficients, e.g. channel state information [CSI]

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Abstract

The invention relates to a combined target relay selection and antenna selection in a full-duplex relay network, wherein the operation steps of combining a target node, a relay node and a relay antenna selection in the relay network are as follows: (1) and the Source Node (SN) calculates the signal-to-noise ratio (SNR) of the direct transmission link from the SN to the Destination Node (DN), and selects the optimal DN according to the SNR. (2) And calculating the signal-to-interference-and-noise ratio (SINR) of the relay link when the two relay antennas work in a transmitting/receiving or receiving/transmitting mode, and selecting the transmitting/receiving mode of the relay antennas according to the SINR of the relay link. The invention utilizes partial CSI, and reduces the complexity of the system. And an optimal DN, an optimal RN and an antenna working mode are selected, so that the performance of the system is improved.

Description

Full-duplex relay combined target-relay-antenna selection method
Technical Field
The invention relates to a combined target node, relay and relay antenna selection strategy used in a full-duplex relay network. Specifically, an optimal destination node is selected from a destination node, then a working mode of a relay antenna is selected according to the optimal destination node, an optimal relay is selected, and finally a link is selected from an optimal direct transmission link and an optimal relay link for information transmission, and the method belongs to the technical field of wireless communication.
Background
Full-duplex relay transmission can improve the spectrum efficiency and the capacity of a relay network, and therefore the technology is adopted in future wireless communication networks. In a full-duplex relay network, relayed receive and transmit signals are simultaneously co-frequency, whereas in a half-duplex relay network, relayed receive and transmit signals are in orthogonal channels. The full-duplex relay network can improve the system capacity of the relay network and can also improve the performance of cell edge users. However, since in a full-duplex relay network, the receiving antenna of the relay can receive the signal transmitted by the relay transmitting antenna, there is strong self-interference at the relay node. Therefore, self-interference cancellation techniques need to be employed in full-duplex relay networks to cancel the effects of self-interference. Many techniques for interference cancellation have been proposed, such as antenna separation and time domain interference cancellation. However, due to the practically imperfect interference cancellation process, the self-interference cannot be completely cancelled, and some self-interference remains inevitably. The residual self-interference is typically modeled as a fading channel.
In an actual multi-destination node and multi-relay system, the selection of a relay and a part of a destination node for cooperative communication can improve the performance of the system by utilizing cooperative diversity and multi-user diversity of a relay network. At the same time, signal loading and operational complexity are reduced. In the conventional joint destination node relay selection scheme, the direct link between the source node and the destination node is not considered. But in some simple three-node models the direct link is considered as one transmission path to eliminate zero diversity in a full-duplex relay network. There are currently few articles that apply direct links in multi-destination node multi-relay networks. Also, almost all work in multi-purpose node multi-relay systems assumes that the transmit and receive antenna patterns of the relay do not change. However, when the link quality from the source node to the relay receiving antenna or from the transmitting antenna to the destination node is deteriorated, the performance of the system is affected. Therefore, it is worth considering that the transmission and reception modes of the antennas at the relay are adaptively adjusted according to the link status. In addition, in order to improve the performance of the relay system, the MIMO relay network is being intensively studied because the efficiency of transmission and the spectral efficiency can be improved.
Disclosure of Invention
In view of the above, the present invention provides a low complexity strategy for combining destination node, relay and relay antenna mode selection in a multi-destination node multi-relay network. In the multi-destination node and multi-relay network, firstly, the optimal destination node is selected to receive the message according to the direct transmission link between the source node and the destination node. Then based on the selected optimal destination node, the relay node obtains channel state information from the optimal destination node and the source node to the two antennas, the relay node calculates SINR of a relay link when the two antennas work in a sending/receiving or receiving/sending mode, and a sending transmission mode of each antenna is configured in a relay mode. And then selecting an optimal relay link according to the configured relay. And selecting one from the optimal direct transmission link and the optimal relay link for information transmission. The selection strategy of the combined destination node, the relay and the relay antenna can work in a distributed mode, so that the complexity of channel state information is reduced, and the performance of the system is improved.
In order to achieve the above object, the present invention provides a low complexity strategy for joint destination node, relay and relay antenna selection for a multi-destination node multi-relay network. This method is used in the following scenarios: the full-duplex relay network comprises M destination nodes, N relay nodes and an information source node. Wherein there are two antennas per relay node and operating in full duplex mode. The two antennas at the relay node may operate in a transmit/receive or receive/transmit mode. We assume that a direct link between the source node S and the destination node D can be used to pass messages. In particular, we assume that there are L antennas at the source node and that beamforming techniques are employed. But because of cost and complexity constraints, there is only one antenna at each destination node. Two antennas are provided at each relay, one for receiving signals and the other for transmitting signals. And the transmitting and receiving modes of the antennas are dynamically selected according to the state of the relay link. The Residual self-interference (RSI) between the two antennas at the relay does not change with the change of the antenna mode. And, all links satisfy the block rayleigh fading. The operation steps of combining the selection of the destination node, the relay and the relay antenna are as follows:
(1) and (3) selecting an optimal destination node: beamforming techniques are employed at the source node. Firstly, a source node sends a signal to a destination node through a direct transmission link by using MRT, and the destination node selects the optimal destination node according to a received SNR.
(2) Optimal relay and relay antenna pattern selection procedure: and the optimal destination node feeds back the channel state information from the two antennas at the relay to the optimal destination node to the corresponding relay, and the relay also obtains the channel state information from the information source to each antenna. And the relay calculates the SINR when the relay antenna works in a transmitting/receiving or receiving/transmitting mode according to the obtained channel state information, and selects the antenna mode with the maximum SINR as the working mode of the relay antenna. And simultaneously, selecting the relay with the maximum SINR as the optimal relay according to SINRs of different relays. And the source node selects one link from the optimal direct transmission link and the optimal relay link to transmit signals.
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FIG. 1 is a flow chart scheme of the present invention illustrating the workflow of the present invention.
Fig. 2 is an application scenario of the present invention: and a system model diagram based on multi-purpose nodes and joint purpose, relay and antenna selection of the multi-relay nodes.
Fig. 3 is a case of interruption probability under different relay numbers in the embodiment of the present invention.
Fig. 4 shows the interruption probability situation under different self-interference situations in the embodiment of the present invention.
Fig. 5 is a flowchart illustrating comparing outage probabilities of different relay destination node selection schemes according to an embodiment of the present invention.
Reference scheme 1 in fig. 5 is g.o.keye, w.a.krzynien, y.lacing, and j.melzer, "a novel-complex joint user-relay selection and association for multi-user multi-relay MIMO uplink," IEEE commnun.let., vol.4, No.3, pp.309-312, june.2015
Reference scheme 2 is C.Zhong, H.A.Suraweera, G.Zhong, I.Krikidis, and Z.Zhang, "Improving the throughput of wireless powered dual-hop systems with full duplex playback," Proc. IEEE int.Conf.Commin.2015, pp.4253-4258, June.2015
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is further described in detail with reference to the accompanying drawings.
Referring to fig. 1, an application scenario of the present invention is described first: in a relay network, there is oneAn information source node S, L antennas are configured for the source node S, and M destination nodes DmM1, 2, …, M, N FD relays RnN is 1,2, …, N. L antennas exist at the source S, and the MRT technology is used for transmitting signals. Relay RnThere are two antennas, one for receiving and the other for transmitting signals, and the transmit-receive mode of the antennas is dynamically selected according to the instantaneous SINR of the relay link, and the relay operates in full duplex mode. Destination node DmWhere only one antenna is present. Source S and destination DmThe direct link between exists and is capable of transferring signals.
(1) Selecting an optimal destination node: firstly, through direct transmission link, information source S utilizes MRT technique to transmit signal xsTo the destination node, then destination node DmThe received signal can be expressed as
Figure BDA0001100831300000041
The SNR received by the destination node may be expressed as
Figure BDA0001100831300000042
Wherein h ismRepresented as source S and destination DmThe channel between. PsRepresenting the transmission power of the source. N is a radical of0Representing the power of the noise.
(11) According to destination node DmSelects the optimal destination node D according to the received SNRm*. Optimal destination node Dm*Satisfy the requirement of
Figure BDA0001100831300000043
(2) Selecting the optimal relay and the working mode of the relay antenna: the antenna at the relay is denoted Tj/TkWherein T isjDenotes a receiving antenna, TkDenotes the transmitting antenna, j, k ∈ 1,2, and j ≠ kjReceiving the signal transmitted by the source S is represented as
Figure BDA0001100831300000044
And using an antenna TkTo be provided with
Figure BDA0001100831300000045
Is sent to the optimal destination node Dm*The antenna T at the relaykThe transmitted signal may be represented as
Figure BDA0001100831300000046
Wherein
Figure BDA0001100831300000047
At the optimal destination node D through the relay linkm*Where the received signal is represented as
Figure BDA0001100831300000048
The received SINR may be expressed as
Figure BDA0001100831300000051
Wherein
Figure BDA0001100831300000052
Represents a relay RnAt an antenna TkWith the optimal destination node
Figure BDA0001100831300000053
The channel between.
Figure BDA0001100831300000054
Representing source S and relay RnAt an antenna TjThe channel between.
Figure BDA0001100831300000055
Represents a relay RnTo a transmitting antenna TkAnd a receiving antenna TjThe remaining self-interference channel in between. PrIndicating the transmission power of the relay.
(21) First select relay RnThe transmission and reception mode of two antennas can be expressed as
Figure BDA0001100831300000056
Wherein
Figure BDA0001100831300000057
Represents a relay RnAntenna T1As transmitting antennas, T2As a receiving antenna.
Figure BDA00011008313000000512
Represents a Relay RnT of2The antenna being a transmitting antenna, T1As a receiving antenna.
(22) Selecting optimal relays from all relays
Figure BDA0001100831300000059
Optimal relay satisfaction
Figure BDA00011008313000000510
Selecting the optimal link from the direct transmission link and the relay link to transmit signals, the end-to-end SINR of the system can be expressed as
Figure BDA00011008313000000511
In order to demonstrate the utility of the present invention, the applicant conducted a number of simulation experiments. The network model in the experimental system is an application scenario shown in fig. 1. The results of the simulation experiments are shown in fig. 2, 3 and 4, and are simulated from the aspect of the interruption probability of the system.
The above description is only a preferred embodiment of the present invention, and should not be taken as limiting the invention, and any modifications, equivalents, improvements and the like made within the spirit and principle of the present invention should be included in the scope of the present invention.

Claims (1)

1. A full duplex relay combination destination-relay-antenna selection method in a relay network having a source node, a plurality of relay nodes, and a plurality of destination nodes, wherein two antennas are present at the relay nodes, one for receiving signals and the other for transmitting signals, the method comprising the steps of:
(1) and (3) selecting an optimal destination node: each destination node transmits channel state information of a direct transmission link from a source node to the destination node to the source node; the information source node calculates the SINR of the direct transmission link according to the received channel state information, and then selects a target node with the maximum SINR as an optimal target node for receiving information; the specific selection method comprises the following steps:
(11) the source node transmits signals to the destination node through a direct transmission link by utilizing a transmitting beam forming technology, and the signals received by the destination node are represented as
Figure RE-FDA0002309874770000012
Wherein h ismRepresenting a source S and a destination DmChannel between wsTransmit beamforming vector, P, for energy normalization at source SsRepresenting the transmission power of the source; the SNR received by the destination node over the direct link may be expressed as
Figure RE-FDA0002309874770000011
N0A power representing noise;
(12) selecting the optimal destination node according to the SNR of the direct transmission link received by the destination node
Figure RE-FDA0002309874770000014
Optimal destination node
Figure RE-FDA0002309874770000015
Satisfy the requirement of
Figure RE-FDA0002309874770000013
(2) Optimal relay and relay antenna mode selection: the optimal destination node feeds back channel state information from two antennas at the relay to the optimal destination node to the corresponding relay, the relay also obtains the channel state information from the information source to each antenna, the relay calculates the SINR of the relay antenna when the relay antenna works in a sending/receiving or receiving/sending mode according to the obtained channel state information, the antenna mode with the maximum SINR is selected as a working mode, and the relay with the maximum SINR is selected as the optimal relay according to the SINR of different relays; the information source node selects a link from the optimal direct transmission link and the optimal relay link for transmitting signals; the specific selection method comprises the following steps:
(21) suppose relay RnAt an antenna Tj/TkIs set as a receiving and transmitting antenna j, k ∈ {1, 2}, j ≠ k, and a relay receiving antenna TjThe received signal is represented as
Figure RE-FDA0002309874770000024
Wherein
Figure RE-FDA0002309874770000025
Representing source S and relay node RnReceiving antenna TjOf between, PrWhich indicates the transmission power of the relay and,
Figure RE-FDA0002309874770000026
represents a relay RnTo a transmitting antenna TkAnd a receiving antenna TjThe residual self-interference channel between, the signal sent by the relay is expressed as
Figure RE-FDA0002309874770000021
When selecting RnThe signal received by the optimal destination node is expressed as
Figure RE-FDA0002309874770000027
Then the relay link received by the optimal destination node is obtained from end to end
Figure RE-FDA0002309874770000022
N0A power representing noise;
(22) the mode of operation of the antenna at each relay is first selected, i.e. calculated
Figure RE-FDA0002309874770000028
Different values of j, k ∈ {1, 2}, j ≠ k are determined by expansion and comparison, and are expressed as
Figure RE-FDA0002309874770000029
Then the optimal relay is selected
Figure RE-FDA00023098747700000211
Optimal relay satisfaction
Figure RE-FDA00023098747700000210
Then system end-to-end SINRγCan be expressed as
Figure RE-FDA0002309874770000023
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