Physical layer network coding system and method based on FQPSK modulation

Abstract

The invention provides a physical layer network coding system and method based on FQPSK (Feher patented Quadrature Phase Shift Keying) modulation. The method is characterized in that a transmitting terminal unit comprises the following steps: A, respectively emitting raw information xA and xB by two signal sources; B, respectively modulating the two pieces of raw information xA and xB after completion of respective modulation to a high-frequency carrier to be changed into emission signals zA and zB; and C, expressing the mixed signals received by a relay module as YR(t)={zA(t)+n(t)}+{zB(t)+n'(t)}, where YR(t) represents the received mixed waveform signals. The method has the benefits that the FQPSK modulation is adopted to perform constant envelope protection for the physical layer network encoded signals, which successfully solves the problem of detection and classification for stacked signals at the relay; and a waveform cluster classification criteria replaces a constellation classification criteria so as to avoid the defect that the FQPSK modulation constellation is ruleless.

Description

technical field [0001] The invention relates to a physical layer network coding technology under a nonlinear channel, in particular to a physical layer network coding system and method based on FQPSK modulation. Background technique [0002] Physical layer network coding: [0003] Network coding technology is considered to be a major breakthrough in the field of communication in this century. It has become an effective method to improve network throughput, robustness, load balancing and security. In a limited network environment, is it theoretical or practical? Important results have been achieved in application, and are favored by academic circles at home and abroad. However, in wireless cooperative communication networks, the interference between signals hinders the application of network coding in multi-hop wireless networks such as wireless Mesh networks, sensor networks and Ad Hoc networks. Until 2006, the concept of physical layer network coding was proposed, which e...

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Problems solved by technology

Second, the existing relay classification criteria are all based on phase. For modulations with ambiguous phase points, such as FQPSK modulation, the relay classification criteria are no longer applicable, and a new classification criteria needs to be found

The phases of FQPSK are irregularly distributed on a unit circle. After the two relay signals are superimposed, the entire superimposed constellation diagram is messy and disorderly, and it is impossible to use the existing constellation classification criteria to classify it.

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