We first review the fundamentals of directional modulation (DM) based on frequency diverse arrays (FDA), which is capable achieving angle-range dependent point-to-point physical layer secure communications where phase shifters FDA-based DM must be optimized continuously with time by complex algorithms like genetic algorithm (GA). Thereafter, in order to overcome time-variant drawbacks conventional DM, we propose a time-invariant time-modulated logarithmically increasing offset FDA...

Opportunistic channel access in cognitive radio networks (CRNs) under an unknown environment is gradually receiving a great deal of attention. This article studies the basic problem decentralized secondary users (SUs) performing multiple sensing and CRN, when not perfect. The availability information must be estimated learned through big-data samples from wireless channels by SUs. Both independent identical distribution (i.i.d.) model Markov are considered. In i.i.d. model, each modeled as...

Quasi cyclic LDPC (QC-LDPC) codes consisting of circulant permutation matrices (CPM-QC-LDPC) are one the most attractive types due to their many advantages. In this paper, we mainly do some research on CPM-QC-LDPC codes. We first propose a two-stage decoding scheme based parity check matrix transform (MT), which can efficiently improve bit error rate performance. To optimize tradeoff between hardware implementation complexity and performance, an improved method that combines our proposed MT...

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We investigate the problem of network selection for Internet Things (IoT) to maximize Quality Experience (QoE) in a heterogeneous wireless environment. Different from traditional access approaches with assumption that state information (NSI) is static and known priori, scenario where NSI networks unknown dynamic IoT devices considered. Due hardware limitations IoT, device has limited resource budget consumes resources, e.g., energy, during process access. To cumulative QoE before exhausts,...

A directional modulation (DM) aided secure spatial (SM) scheme is proposed, which amalgamates the security of DM and high efficiency SM, capable achieving physical layer (PLS) communications for SM.The principle proposed SM analyzed.Besides, optimal maximum likelihood (ML) detector a low-complexity near-ML (NML) are given receiver in desired direction, respectively.Simulation results demonstrate that 1) exhibits excellent BER performance at while worsens undesired receivers 2) NML reduces...

Considering the current rapid development of space equipment and increasingly urgent demand for using frequency orbit resources (SFOR), future global orbital layout, this paper proposes a comprehensive method evaluating effectiveness resources. To address issue, we build judgment matrix evaluation in absence expert advice, utilize entropy weights (EWM) to analytical hierarchy process (AHP) measure SFOR. The proposed methods is finally validated by numerical tests.

As one of the most potential types low-density parity-check (LDPC) codes, CPM-QC-LDPC code has considerable advantages but there still exist some limitations in practical application, for example, existing decoding algorithm a low convergence rate and high complexity.According to structural property this code, we propose new method based on CPM-RID that decodes block-by-block with weights, which are obtained by neural network training.From simulation results, can conclude our proposed not...

A polarization hopping wireless communication system is proposed, the matching relationship between sequence and states of antennas designed, a synchronization acquisition scheme put forward for proposed system.Then detection false alarm probabilities are analyzed simulated under different pseudo-random sequences using MATLAB.The results demonstrate that can achieve best performance with RS sequence, they also verify feasibility scheme.

This paper proposes a two-stage iterative decoding scheme named matrix transform belief propagation (MT-BP) based on conventional (BP) algorithm for lowdensity parity-check (LDPC) codes.By introducing information measurement, location vectors and parity check transform, the proposed method can establish additional equations take more bits of variable nodes into consideration compared with BP algorithm.The simulations are performed random regular LDPC codes algebraic quasi-cyclic (QC-LDPC),...

A low-complexity time-invariant angle-range dependent directional modulation (DM) based on time-modulated frequency diverse array (TM-FDA-DM) is proposed to achieve point-to-point physical layer security communications. The principle of TM-FDA elaborated and the vector synthesis method utilized realize proposal, TM-FDA-DM, where normalization orthogonal matrices are designed modulate useful baseband symbols inserted artificial noise, respectively. Since two fixed values, which avoid...