Adaptive coding and modulation scheme for satellite-UMTS TDD systems based on a photogrammetric channel estimation method

2006 ◽  
Vol 24 (1) ◽  
pp. 23-34 ◽  
Author(s):  
Hsin-Piao Lin ◽  
Ming-Chien Tseng ◽  
Chin-Ching Teng
Keyword(s):  
Channel Estimation ◽  
Estimation Method ◽  
Modulation Scheme ◽  
Adaptive Coding

scholarly journals Enhanced NOMA System Using Adaptive Coding and Modulation Based on LSTM Neural Network Channel Estimation

2019 ◽  
Vol 9 (15) ◽  
pp. 3022 ◽  
Author(s):  
AbdelMoniem ◽  
Gasser ◽  
El-Mahallawy ◽  
Fakhr ◽  
Soliman
Keyword(s):  
Neural Network ◽  
Channel Estimation ◽  
Multiple Access ◽  
Short Term Memory ◽  
Power Coefficient ◽  
Modulation Scheme ◽  
Channel Fading ◽  
Adaptive Coding ◽  
Time Frequency ◽  
Shift Keying

Non-orthogonal multiple access (NOMA) is the technique proposed for multiple access in the fifth generation (5G) cellular network. In NOMA, different users are allocated different power levels and are served using the same time/frequency resource blocks (RBs). The main challenges in existing NOMA systems are the limited channel feedback and the difficulty of merging it with advanced adaptive coding and modulation schemes. Unlike formerly proposed solutions, in this paper, we propose an effective channel estimation (CE) algorithm based on the long-short term memory (LSTM) neural network. The LSTM has the advantage of adapting dynamically to the behavior of the fluctuating channel state. On average, the use of LSTM results in a 10% lower outage probability and a 37% increase in the user sum rate as well as a maximal reduction in the bit error rate (BER) of 50% in comparison to the conventional NOMA system. Furthermore, we propose a novel power coefficient allocation algorithm based on binomial distribution and Pascal’s triangle. This algorithm is used to divide power among N users according to each user’s channel condition. In addition, we introduce adaptive code rates and rotated constellations with cyclic Q-delay in the quadri-phase shift keying (QPSK) and quadrature amplitude modulation (QAM) modulators. This modified modulation scheme overcomes channel fading effects and helps to restore the transmitted sequences with fewer errors. In addition to the initial LSTM stage, the added adaptive coding and modulation stages result in a 73% improvement in the BER in comparison to the conventional NOMA system.

A Low-Complexity Sparse Channel Estimation Method for OFDM Systems

2010 ◽  
Vol E93-B (8) ◽  
pp. 2211-2214
Author(s):  
Bin SHENG ◽  
Pengcheng ZHU ◽  
Xiaohu YOU ◽  
Lan CHEN
Keyword(s):  
Channel Estimation ◽  
Estimation Method ◽  
Low Complexity ◽  
Ofdm Systems ◽  
Sparse Channel Estimation ◽  
Sparse Channel

Channel Estimation Method Using Arbitrary Amplitude and Phase Modulation Schemes for MIMO Sensor

2014 ◽  
Vol E97.B (10) ◽  
pp. 2102-2109
Author(s):  
Tsubasa TASHIRO ◽  
Kentaro NISHIMORI ◽  
Tsutomu MITSUI ◽  
Nobuyasu TAKEMURA
Keyword(s):  
Channel Estimation ◽  
Phase Modulation ◽  
Estimation Method ◽  
Arbitrary Amplitude ◽  
Modulation Schemes

scholarly journals Low-complexity beam-domain channel estimation and power allocation in hybrid architecture massive MIMO systems

2019 ◽  
Vol 2019 (1) ◽  
Author(s):  
Xiao Chen ◽  
Zaichen Zhang ◽  
Liang Wu ◽  
Jian Dang
Keyword(s):  
Channel Estimation ◽  
Power Allocation ◽  
Spectral Efficiency ◽  
Communication Systems ◽  
Mimo Systems ◽  
Beam Steering ◽  
Estimation Method ◽  
Low Complexity ◽  
Estimation Accuracy ◽  
Hybrid Architecture

Abstract In this journal, we investigate the beam-domain channel estimation and power allocation in hybrid architecture massive multiple-input and multiple-output (MIMO) communication systems. First, we propose a low-complexity channel estimation method, which utilizes the beam steering vectors achieved from the direction-of-arrival (DOA) estimation and beam gains estimated by low-overhead pilots. Based on the estimated beam information, a purely analog precoding strategy is also designed. Then, the optimal power allocation among multiple beams is derived to maximize spectral efficiency. Finally, simulation results show that the proposed schemes can achieve high channel estimation accuracy and spectral efficiency.

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