Enhanced Spread Spectrum Aloha (E-SSA), an emerging satellite return link messaging scheme

Reichman, Arie

doi:10.1109/eeei.2014.7005842

Cited by 10 publications

(6 citation statements)

References 3 publications

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“…In this section, we simulate the pilot collision probability, decoding failure probability and AFP of LSP-GFMA scheme with LPS, ZCS, and mZCS. Then, we compare AFP and achievable throughput of LSP-GFMA scheme with the existing GFMA schemes, including the modified approximate message passing (M-AMP) [57] and the E-SSA schemes [58] with mZCS and ZCS, respectively. Both the M-AMP and E-SSA schemes adopt the RP structure.…”

Section: Simulation Results and Discussionmentioning

confidence: 99%

Low-Correlation Superimposed Pilot Grant-Free Massive Access for Satellite Internet of Things

Xu,

Jiao,

Wang

et al. 2023

IEEE Trans. Commun.

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Satellite Internet of Things (S-IoT) with low Earth orbit satellites has become an effective solution for providing global coverage for massive machine type communications (mMTC). Considering that the massive user equipments covered by the S-IoT are periodically activated and dominated by short packet communications, the pilot collision has become a challenging problem due to the limited length and number of pilot sequences. In this paper, we propose a low-correlation superimposed pilot grant-free massive access (LSP-GFMA) scheme, where a low-correlation-zone periodic sequence (LPS) is designed for the superimposed pilot (SP) structure. Our LPS can maintain low cross-correlation with random non-orthogonal shifts compared with the conventional Zadoff-Chu sequence (ZCS), which can alleviate pilot collision while ensuring high spectral efficiency.In addition, we propose an iterative channel estimation based on Kaczmarz algorithm to attain accurate channel state information for the SP structure with low complexity. Then, we derive the theoretical expressions of access failure probability (AFP) and achievable throughput for our LSP-GFMA scheme under the shadowed-Rician fading channel. Simulation results validate the accuracy of our theoretical derivations, and demonstrate that our LSP-GFMA scheme with LPS can achieve lower AFP and higher achievable throughput than that with ZCS, and also outperforms the state-of-the-art schemes.

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Section: Simulation Results and Discussionmentioning

confidence: 99%

Low-Correlation Superimposed Pilot Grant-Free Massive Access for Satellite Internet of Things

Xu,

Jiao,

Wang

et al. 2023

IEEE Trans. Commun.

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“…It changes the mechanism in CRDSA, where terminals send a fixed number of copies to select the number of copies based on probability distribution. In addition, some protocols adopt spread spectrum technology to improve the system throughput, such as spread spectrum ALOHA (SSA) and enhanced spread spectrum ALOHA (E-SSA) [ 15 , 16 ]. Since the spreading code has a time-delay capture characteristic, as long as the arrival times of two packets are not absolutely identical, these packets can be considered quasi-orthogonal.…”

Section: Introductionmentioning

confidence: 99%

An Asynchronous Collision-Tolerant ACRDA Scheme Based on Satellite-Selection Collaboration-Beamforming for LEO Satellite IoT Networks

Hong

Liu

et al. 2023

Sensors

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In this paper, an asynchronous collision-tolerant ACRDA scheme based on satellite-selection collaboration-beamforming (SC-ACRDA) is proposed to solve the avalanche effect caused by packet collision under random access (RA) high load in the low earth orbit (LEO) satellite Internet of Things (IoT) networks. A non-convex optimization problem is formulated to realize the satellite selection problem in multi-satellite collaboration-beamforming. To solve this problem, we employ the Charnes-Cooper transformation to transform a convex optimization problem. In addition, an iterative binary search algorithm is also designed to obtain the optimization parameter. Furthermore, we present a signal processing flow combined with ACRDA protocol and serial interference cancellation (SIC) to solve the packet collision problem effectively in the gateway station. Simulation results show that the proposed SC-ACRDA scheme can effectively solve the avalanche effect and improve the performance of the RA protocol in LEO satellite IoT networks compared with benchmark problems.

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“…However, this approach needs further synchronization processes between the satellite and end-devices, which would increase their energy consumption. It should also mention the potential use of enhanced spreadspectrum ALOHA [11] and Asynchronous contention resolution diversity ALOHA [12] for LEO satellite IoT, in order to reduce the probability of packet loss.…”

Section: Introductionmentioning

confidence: 99%

A New LoRa-like Transceiver Suited for LEO Satellite Communications

Temim

Ferré

Tajan

2022

Sensors

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LoRa is based on the chirp spread spectrum (CSS) modulation, which has been developed for low power and long-range wireless Internet of Things (IoT) communications. The structure of LoRa signals makes their decoding performance extremely sensitive to synchronization errors. To alleviate this constraint, we propose a modification of the LoRa physical layer, which we refer to as differential CSS (DCSS), associated with an original synchronization algorithm. Based on this modification, we are able to demodulate the received signals without performing a complete frequency synchronization and by tolerating some timing synchronization errors. Hence, our receiver can handle ultra narrow band LoRa-like signals since it has no limitation on the maximum carrier frequency offset, as is actually the case in the deployed LoRa receivers. In addition, in the presence of the Doppler shift varying along the packet duration, DCSS shows better performance than CSS, which makes our proposed receiver a good candidate for communication with a low-Earth orbit (LEO) satellite.

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Enhanced Spread Spectrum Aloha (E-SSA), an emerging satellite return link messaging scheme

Cited by 10 publications

References 3 publications

Low-Correlation Superimposed Pilot Grant-Free Massive Access for Satellite Internet of Things

Low-Correlation Superimposed Pilot Grant-Free Massive Access for Satellite Internet of Things

An Asynchronous Collision-Tolerant ACRDA Scheme Based on Satellite-Selection Collaboration-Beamforming for LEO Satellite IoT Networks

A New LoRa-like Transceiver Suited for LEO Satellite Communications

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