CN104539403B - Implementation method based on ARQ agreements in the SWIPT junction networks relayed more - Google Patents

Abstract

The invention discloses a kind of implementation method based on ARQ agreements in the SWIPT junction networks relayed more, the agreement includes：In transmitting terminal, source node waits the feedback information from destination node to destination node broadcast transmission packet.In receiving terminal, destination node is detected according to the information received, if being properly received the information, destination node then can broadcast acknowledgements signal ACK, source node then continues to transmit next new packet after receiving the signal, and otherwise destination node can then broadcast non-acknowledgement signal NACK.Now, the relaying being correctly decoded carries out the transmission again of packet according to two kinds of Merge Scenarioses of the present invention.

Description

Realization method of ARQ protocol in SWIPT relay network based on multi-relay

technical field

The invention relates to a relay cooperative transmission protocol in the technical field of mobile communication, in particular to a method for realizing the ARQ protocol in a multi-relay-based SWIPT (signal energy simultaneous interpretation) relay network.

Background technique

Relay cooperative communication is an effective strategy to exploit the available spatial diversity among distributed single-antenna terminals. Due to the natural distribution of relay nodes in wireless relay networks, the performance of wireless communication systems can be significantly improved in resource-constrained or large-scale relay networks. However, when the data sent by the source node to the destination node is successfully decoded, it is unnecessary to relay at this time. Considering that the relay stage will occupy a part of the bandwidth of the channel, the enhanced relay or cooperative ARQ protocol is proposed. It is expected to achieve better spectral efficiency.

In energy-constrained wireless relay networks, such as wireless sensor networks, nodes are usually equipped with fixed energy supply devices, such as batteries. In this way, in scenarios where it is inconvenient to charge or replace the battery, the life time of the relay network will be limited. Harvesting energy from the natural environment, such as solar energy and wind energy, provides a new energy supply method for the relay network. In addition to these commonly used energy sources, energy harvesting from radio frequency signals is attracting increasing attention because the harvested energy is more or less manageable. Based on the concept of letter-energy simultaneous interpretation communication, the simultaneous transmission of information and energy is proposed. Then, two practical receiver structures are designed, called Time Switching (TS) structure and Power Distribution (PS) structure respectively. Simultaneous Interpretation Communication with Signal Energy is naturally applied to the relay network. In the relay network, the relay node collects energy from the radio frequency signal of the source node and uses the collected energy to forward the information of the source node to the destination node. Then, selecting one or more suitable relay nodes is very important to improve the performance of the system. However, for energy-constrained relay networks, most of the research focuses on the energy harvesting of relay nodes. So far, there is no relay selection protocol specially designed for SWIPT wireless relay networks with feedback information.

Contents of the invention

The purpose of the present invention is to overcome the defects in the above-mentioned prior art, and provide an implementation method of the ARQ protocol in a multi-relay-based SWIPT relay network. Compared with traditional transmission methods, the method can effectively improve the performance of the system.

To achieve the above object, the present invention is achieved through the following technical solutions:

The realization method of ARQ agreement in the SWIPT relay network based on multi-relay, comprises the following steps:

1) At the sending end, the source node first broadcasts the data packet to be sent to the relay node and the destination node in the network, and waits for the feedback information from the destination node. The feedback information is the confirmation information ACK or the non-confirmation information NACK;

2) At the receiving end, the destination node performs information detection according to the received data packet. If the information detection is correct, the confirmation information ACK is broadcast to the source node and the relay node, and if not, the non-confirmation information is broadcast to the source node and the relay node NACK;

3) In a wireless relay network composed of M relays capable of energy harvesting, the relay adopts the decoding-forwarding method. If the relay receives the confirmation information ACK broadcast from the destination node, it will initialize, that is, erase All the received information and collected energy (the energy is restored to the initial value of zero); otherwise, select multiple relays from the correctly decoded relays to retransmit the data packet; among them, M>1;

If the information received by the source node and the relay node is NACK, proceed as follows:

31) Each relay node adopts the energy harvesting mode based on the power splitting architecture, and each relay node adopts the same power splitting ratio. In a network composed of M relay nodes, the relay nodes are determined in advance according to The information received by the power split ratio ρ is decoded, where 0≤ρ≤1;

32) After all relays are decoded, the relay network is divided into two parts, one part is composed of relays that cannot be decoded correctly, and the other part is a collection of relays that can be correctly decoded;

33) In the set of relays that can be decoded correctly, the relay uses the received energy as the energy required to send information this time. In the correctly decoded relay combination, all relay nodes participate in the retransmission process. The relay will send correctly decoded data packets to the destination node in turn, and each transmission will occupy a time slot. Here, the number of retransmissions is specified as 1, that is, each relay in the selected relay combination can only retransmit once. If the destination node still cannot receive it correctly, the data packet at this time is discarded, the source node starts the transmission of the next new data packet, and the destination node performs equal-gain combination or maximum-ratio combination.

The further improvement of the present invention is that in step 2), at the receiving end, the destination node checks whether the information is correct or not, and if the information detection is correct, the destination node broadcasts confirmation information ACK to the source node and the relay node, and the source node will Transmit the next new data packet; otherwise, broadcast the non-confirmation information NACK to the source node and the relay node, and enter the retransmission stage participated by the relay.

A further improvement of the present invention is that in step 3), if the relay network has no correctly decoded relays, there is no retransmission process involving relays.

Compared with the prior art, the present invention has the following technical effects:

The present invention is based on the implementation method of the ARQ protocol in the multi-relay SWIPT relay network. The method adopts a communication system with feedback information, that is, it is judged whether the relay participates in this information according to the feedback information of the destination node. In transmission, compared with traditional relay networks using equal-gain combination or maximum-ratio combination, spectral efficiency can be improved; in addition, under this system, the relay network with limited energy collects energy and uses the collected energy for transmission. The relay is self-contained, so there is no need to change batteries, especially in harsh environments (poisonous, canyons, etc.).

Description of drawings

Fig. 1 is the flowchart of the realization method of ARQ agreement in the SWIPT relay network based on multi-relay of the present invention;

Fig. 2 is the model block diagram of ARQ transmission system among the present invention;

Fig. 3 is the PS architecture diagram of CITIC simultaneous interpretation relay in the present invention;

Fig. 4 is a simulation performance diagram in the present invention.

detailed description

The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments.

Suppose the network includes a source node S, a destination node D, and M relay nodes R, h _k is the channel state information of the forward link of the kth relay node, and g _k is the kth relay node The channel state information of the forward link.

Referring to Fig. 1 to Fig. 3, the present invention is based on the realization method of ARQ agreement in the SWIPT relay network of multi-relay, comprises the following steps:

1) At the sending end, the source node first broadcasts the data packet to be sent to the relay node and the destination node in the network, and waits for the feedback information from the destination node. The feedback information is the confirmation information ACK or the non-confirmation information NACK;

2) At the receiving end, the destination node performs information detection according to the received data packet. If the information detection is correct, the confirmation information ACK is broadcast to the source node and the relay node, and if not, the non-confirmation information is broadcast to the source node and the relay node NACK;

3) In a wireless relay network composed of M relays capable of energy harvesting, the relay adopts the decoding-forwarding method. If the relay receives the confirmation information ACK broadcast from the destination node, it will initialize, that is, erase All received information and collected energy, the energy is restored to the initial value of zero; otherwise, one or more relays are selected from the correctly decoded relays to retransmit the data packet; among them, M>1.

Among them, in the above step 2), at the receiving end, the destination node checks whether the information is correct or not. If the information detection is correct, the destination node broadcasts the confirmation information ACK to the source node and the relay node. At this time, the source node will transmit the next new Otherwise, broadcast the non-confirmation information NACK to the source node and the relay node, and enter the retransmission stage participated by the relay.

Wherein, in the above step 3), if the information received by the source node and the relay node is non-acknowledgment information NACK, the ARQ protocol is activated. The specific implementation of this agreement is as follows:

Using a multi-relay-based ARQ protocol, the determination of the coordination node specifically includes the following steps:

31) Each relay node adopts the energy harvesting mode based on the power splitting architecture, and each relay node adopts the same power splitting ratio. In a network composed of M relay nodes, the relay nodes are determined in advance according to The information received by the power split ratio ρ is decoded, where, 0≤ρ≤1; the source node sends information with a fixed power P _s , and the transmitted signal is s, then the signal received by the kth relay node and the received energy They are:

E _k ＝ _ηρPS |h _k | ² T/2＝ _ρPS |h _k | ² T/2; (η＝1)

Among them, n _{a, r} is the antenna noise of the relay node, n _{c, r} is the noise generated by converting the radio frequency signal into the baseband signal at the relay node; η is the conversion efficiency of the energy harvesting circuit, which may be set to 1, as shown in Figure 2 Shown T is the length of a time slot;

32) After all relays are decoded, the relay network is divided into two parts, one part is composed of relays that cannot be decoded correctly, and the other part is a collection of relays that can be correctly decoded;

The transmit power of the kth relay among successfully decoded relays is

The instantaneous SNR of the successfully decoded relay to the destination node is

Among them, σ ² _a,d is the power of the antenna noise at the destination node, and σ ² _c,d is the power of the noise generated by converting the RF signal into the baseband signal at the destination node;

33) In the set of relays that can be decoded correctly, the relay uses the received energy as the energy required to send information this time. In the correctly decoded relay combination, all relay nodes participate in the retransmission process. The relay will send correctly decoded data packets to the destination node in turn, and each transmission will occupy a time slot. Here, the number of retransmissions is specified as 1, that is, each relay in the selected relay combination can only retransmit once. If the destination node still cannot receive it correctly, the current data packet is discarded, and the source node starts the transmission of the next new data packet. The correctly decoded relay sets transmit information sequentially and are orthogonal to each other, as shown in Figure 2. The destination node performs equal gain method (EGC) combination or maximum ratio method (MRC) combination, which is a kind of two combination schemes of the protocol . Considering an extreme case, if the relay network has no correctly decodable relays, then there is no retransmission process involving relays.

If EGC is adopted, the signal-to-noise ratio of the destination node is

If the MRC combination is adopted, the signal-to-noise ratio of the destination node is

m is the number of correctly decoded relays in one transmission;

Simulation experiment and effect analysis

The parameters of the simulation model are: the number of relays M = 4, the transmission rate of the source node R = 1bits/sec/Hz, the power of the noise introduced by the relay node and the destination node is 1/2, and the channel parameter λ _sd = λ _h = λ _k =1.

The analysis of the simulation results shows the optimal power split ratios under different transmit powers obtained through simulation, as shown in the following table:

Send power/dB 1 3 5 7 9 11 13 15 Optimal Power Split Ratio (Equal Gain) 0.51 0.55 0.57 0.59 0.59 0.63 0.63 0.63 Optimal power split ratio (maximum ratio) 0.49 0.53 0.55 0.55 0.59 0.59 0.59 0.61

According to the parameter simulation of the above table, the outage probability performance curve proposed by the present invention is simulated, and the outage probability performance curve of repeated transmission of no relay node and source node is respectively simulated, as can be seen from Fig. 4, the realization of the ARQ protocol proposed in the present invention The performance curve of the method is obviously better than the above two cases, and the performance has been improved, and the two combining schemes in the present invention have little difference, but the equal gain combining is easier to realize than the maximum ratio combining.

Claims (3)

1. the implementation method based on ARQ agreements in the SWIPT junction networks relayed more, it is characterised in that comprise the following steps：

1) in transmitting terminal, via node and the destination node broadcast packet to be sent of the source node first into network, and The feedback information from destination node is waited, feedback information is confirmation ACK or unacknowledged information NACK；

2) in receiving terminal, destination node carries out infomation detection according to the packet received, if infomation detection is correct, to source Node and relay node broadcasts confirmation ACK, if it is not, then to source node and relay node broadcasts unacknowledged information NACK；

3) in the wireless relay network that the via node that collection of energy can be carried out by M forms, via node use decoding- Pass-through mode, if via node receives the confirmation ACK from destination node broadcast, initialized, i.e. erasing connects All information received and the energy being collected into, energy return to initial value of zero；Otherwise selected in the via node being correctly decoded Multiple via nodes are taken to carry out again the operation of transmission packet；Wherein, M>1；

If the information that source node and via node receive is NACK, following steps are carried out：

31) each via node uses using the collection of energy pattern based on power dividing framework, each via node Identical power dividing ratio, in the network being made up of M via node, via node is according to the power having determined in advance Shunting ratio ρ decodes to the information received, wherein, 0≤ρ≤1；

32) after whole via nodes after decoding, junction network is divided into two parts, a part be by that can not be correctly decoded in Formed after node, the set that another part is made up of the via node that can be correctly decoded；

33) in the set for the via node composition that can be correctly decoded, via node is sent the energy of reception as this Energy needed for information, in the via node combination being correctly decoded, all via nodes are involved in transmitting procedure again, in The packet being correctly decoded will be sent to destination node successively after node, transmission every time will take a time slot, herein regulation weight New the number of transmissions is 1, that is, each via node chosen can only transmission primaries again, if hereafter destination node still can not correctly connect Receive, then abandon packet now, source node then starts the transmission of next new packet, and destination node then carries out waiting gain Mode merges or high specific mode merges.

2. the implementation method according to claim 1 based on ARQ agreements in the SWIPT junction networks relayed more, its feature It is, in step 2), in receiving terminal, destination node is according to infomation detection correctness, if infomation detection is correct, destination node is then To source node and relay node broadcasts confirmation ACK, now source node will transmit next new packet；Otherwise, then to Source node and relay node broadcasts unacknowledged information NACK, into the transmission stage again participated in by via node.

3. the implementation method according to claim 1 based on ARQ agreements in the SWIPT junction networks relayed more, its feature It is, in step 3), if the junction network is not participated in again without the via node that can be correctly decoded by via node Transmitting procedure.