Results 21 to 30 of about 4,863,781 (309)

Multi-group frequency hopping OFDMA based on statistical multiplexing [PDF]

, 2008
In this paper, the multi-group frequency hopping OFDMA (MG-FH OFDMA) based on the statistical multiplexing is proposed for the downlink cellular system. Compared with the existed random frequency hopping OFDMA (RFH-OFDMA) system utilizing the statistical
Su, Xinghui, Lv, Tiejun, Yang, Shaoshi, Yun, Xiang, Xiang Yun, Shaoshi Yang, Gong, Ping, Xinghui Su, Ping Gong, Tiejun Lv   +9 more
core   +1 more source

Noncoherent Multi-Way Relay Based on Fast Frequency-Hopping M-ary Frequency-Shift Keying [PDF]

, 2010
Information exchange among a group of users is implemented with the aid of fast frequency-hopping $M$-ary frequency-shift keying multi-way relay (FFH/MFSK MWR). The FFH/MFSK MWR scheme uses two time-slots per symbol for achieving the information exchange,
Cao, Jianfei, Yang, Lie-Liang, Zhong, Zhangdui   +2 more
core   +2 more sources

Area spectral efficiency of soft-decision space–time–frequency shift-keying-aided slow-frequency-hopping multiple access [PDF]

, 2012
Slow-frequency-hopping multiple access (SFHMA) can provide inherent frequency diversity and beneficially randomize the effects of cochannel interference.
Ngo, Hoang Anh, Hoang Anh Ngo, Hanzo, Lajos, Lajos Hanzo   +3 more
core   +1 more source

Millisecond Spin Relaxation Times of Distinct Electron and Hole Subensembles in MA_xFA_1-xPbI₃ Perovskite Crystals. [PDF]

Adv Sci (Weinh)
Mixed‐cation MAx${\rm MA}_x$ FA1−x${\rm FA}_{1-x}$ PbI3${\rm PbI}_3$ perovskite crystals reveal multiple discrete electron and hole spin subensembles associated with distinct localization environments. Optically detected magnetic resonance combined with resonant spin inertia uncovers carriers spin relaxation times reaching 2 ms and identifies nuclear ...
Hu R, Meliakov SR, Yakovlev DR, Turedi B, Kovalenko MV, Bayer M, Belykh VV.   +6 more
europepmc   +2 more sources

FH-BOC: generalized low-ambiguity anti-interference spread spectrum modulation based on frequency-hopping binary offset carrier

GPS Solutions, 2020
Objective The paper aims to present a generalized modulation scheme that can improve the anti-interference performance of global navigation satellite systems (GNSS) and mitigate the ambiguity problem in BOC modulation.
Jian-Gang Ma, Yi-Kang Yang, Hengnian Li, Ji-Sheng Li   +3 more
semanticscholar   +1 more source

Index modulation aided frequency hopping anti-jamming and encryption method based on rotation scrambling

Tongxin xuebao, 2021
In order to improve the anti-jamming ability and security of the wireless communication system， an index frequency-hopping anti-interference encryption method based on rotation scrambling was designed， which could be simply called encrypted index ...
Xinjin LU, Jing LEI, Yuxin SHI
doaj   +2 more sources

Low-False-Alarm-Rate Timing and Duration Estimation of Noisy Frequency Agile Signal by Image Homogeneous Detection and Morphological Signature Matching Schemes

Sensors, 2023
Frequency hopping spread spectrum (FHSS) applies widely to communication and radar systems to ensure communication information and channel signal quality by tuning frequency within a wide frequency range in a random sequence.
Yuan-Pin Cheng, Chia-Hsuan Chang, Jung-Chih Chen   +2 more
doaj   +1 more source

An Interference Sensing Algorithm Based on Duration Units of Frequency Points for Adaptive Frequency-Hopping System

IEEE Access, 2023
The adaptive Frequency-Hopping(FH) technique based on interference sensing can further enhance the anti-interference performance of hybrid Direct-Sequence/FH Spread Spectrum(DS/FH SS) system and FH Orthogonal Frequency Division Multiplexing(FH-OFDM ...
Duo Wang, Ju Wang, Yi Zhong
doaj   +1 more source

A Novel Spread Spectrum and Clustering Mixed Approach with Network Coding for Enhanced Narrowband IoT (NB-IoT) Scalability

Sensors, 2020
The Narrowband Internet of Things (NB-IoT) is a very promising licensed Internet of things (IoT) technology for accommodating massive device connections in 5G and beyond.
Emmanuel Migabo, Karim Djouani, Anish Kurien   +2 more
doaj   +1 more source

Bit error simulation of DQPSK for a slow frequency hopping CDMA system in mobile radio communications [PDF]

, 1995
Spread spectrum (SS) techniques seem to be an attractive alternative to conventional narrow-band modulation. In this paper a frequency hopping (FH) system model based on slow FH (SFH) is proposed.
Mortazavi, SH, Jones, JA, McGeehan, JP, Beach, MA   +3 more
core   +1 more source