6 research outputs found
Efficient Low-Complexity Turbo-Hadamard Code in UAV Anti-Jamming Communications
No full textUnmanned aerial vehicle (UAV) systems undergo a period of rapid development in both civil and military scenarios. A major challenge in the malicious jamming environment is to guarantee the reliability of UAV communications links. Frequency hopping (FH) is one of the most commonly used means of combatting the influence brought about by jamming. In this paper, we integrate low-rate codes into an anti-jamming FH communications system, and propose an efficient and low-complexity turbo-Hadamard code scheme. Tail-biting is applied to design the component convolutional-Hadamard codes, and a corresponding decode algorithm is used for implementation in the UAV hardware platform. Numerical simulation results demonstrate that the anti-jamming performance of this method is improved as compared with conventional concatenated codes. Finally, we compare the complexity and transmission efficiency of the proposed algorithm with the algorithms implemented on the field programmable gate array (FPGA) platform in detail
Secure Rate-Splitting Multiple Access Transmissions in LMS Systems
Get PDFThis letter investigates the secure delivery performance of the
rate-splitting multiple access scheme in land mobile satellite (LMS) systems,
considering that the private messages intended by a terminal can be
eavesdropped by any others from the broadcast signals. Specifically, the
considered system has an N-antenna satellite and numerous single-antenna land
users. Maximum ratio transmission (MRT) and matched-filtering (MF) precoding
techniques are adopted at the satellite separately for the common messages
(CMs) and for the private messages (PMs), which are both implemented based on
the estimated LMS channels suffering from the Shadowed-Rician fading. Then,
closed-form expressions are derived for the ergodic rates for decoding the CM,
and for decoding the PM at the intended user respectively, and more
importantly, we also derive the ergodic secrecy rate against eavesdropping.
Finally, numerical results are provided to validate the correctness of the
proposed analysis models, as well as to show some interesting comparisons.Comment: 5 pages, 3 figures, 1 tabl
