Untrusted relay full duplex transmission method and system combined with sink zero-forcing scrambling

Abstract

The invention provides an untrusted relay full duplex transmission method and system combined with sink zero-forcing scrambling. An information source A sends a secret signal x to a full duplex relayR, and an information sink B sends an artificial noise interference signal v to the full duplex relay R at the same time; the full duplex relay R receives the yR and forwards the signal xR = beta yR to the information sink B by adopting an amplifying and forwarding protocol, and beta is an amplifying and forwarding factor; and the information sink B adopts a maximum ratio receiving strategy to design a receiving vector r = gB, wherein a received signal is yB = rH (gBxR + nB), nB is an NBr*1-dimensional additive white Gaussian noise vector of the information sink B, and NBr is the number of receiving antennas. According to the invention, the transmission efficiency is improved, and the receiving effect of an eavesdropping node on the secret signal is effectively reduced.

Description

technical field [0001] The invention relates to the field of communication systems, in particular to an untrusted relay full-duplex transmission method and system combined with zero-forcing and scrambling at a sink. Background technique [0002] In an untrusted relay communication system, the relay eavesdrops on the information while assisting the source to transmit information. In order to reduce the eavesdropping rate of the relay, the sink scrambling method is usually used, that is, when the source sends confidential information , the sink sends an interference signal, and then relays the received information in the second time slot using the amplification and forwarding protocol. After receiving the information, the sink cancels the interference signal sent by itself, so the interference signal will not reduce the received SINR. [0003] However, the existing solution adopts a half-duplex mode, and the transmission process needs to be completed within two time slots, whi...

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Problems solved by technology

[0003] However, the existing solution uses the half-duplex mode, which needs to complete the transmission process within two time slots, which affects the improvement of the system security rate.

In addition, there are other solutions that use multi-antenna technology to enhance transmission performance. Multi-antenna technology is also divided into two types: 1) beamforming technology, which designs the optimal beamforming vector or matrix with the goal of optimizing the system rate, but the signal of this solution The processing complexity is large, and it increases the difficulty of obtaining channel state information; 2) Antenna selection technology, through a certain antenna selection criterion, selects one or more antennas among the transmitting or receiving antennas to optimize system performance. Low implementation complexity, but insignificant performance improvement over unscrambled schemes

[0004] In addition, there are also solutions that use one or more external friendly scrambling nodes to reduce the eavesdropping effect of untrusted relays by sending friendly interference signals. The friendly interference signals are known to legitimate nodes in advance, so they can be eliminated from the received signal , but this scheme relies on the assistance of external nodes, requires a large amount of information exchanged between nodes, and lacks flexibility and autonomy

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