scholarly journals On the variations in mutual information of MIMO communication systems due to perturbed channel state information at transmitter

2006 ◽  
Vol 54 (9) ◽  
pp. 1593-1603 ◽  
Author(s):  
M.R.B. Shankar ◽  
K.V.S. Hari
2019 ◽  
Vol 13 (10) ◽  
pp. 1458-1464 ◽  
Author(s):  
Mingxuan Zhang ◽  
Weiwei Miao ◽  
Yiting Shen ◽  
Jin Huang ◽  
Shaqian Zhang ◽  
...  

2020 ◽  
Author(s):  
Lei Xu ◽  
Jing Yi Yao ◽  
Jing Cai ◽  
Yu Hong Fang ◽  
Hui Xiao Li

Abstract In a real communication scenario, it is very difficult to obtain the real-time Channel State Information(CSI) accurately, so the communication systems with statistical CSI have been researched. In order to maximize the throughput of the downlink Non-Orthogonal Multiple Access (NOMA) system with statistical CSI, the formula of system throughput is derived at first. Then, according to the combinatorial characteristics of the original optimization problem, it is divided into two subproblems, that is user grouping and power allocation. At last, a joint optimization scheme is proposed. In which, Genetic algorithm is introduced to solve the subproblem of power allocation, and Hungarian algorithm is introduced to solve the subproblem of user grouping. By comparing the ergodic date rate of NOMA users with statistical CSI and perfect CSI, the effectiveness of the statistical CSI sorting is verified. Compared with the Orthogonal Multiple Access (OMA) scheme, the NOMA scheme with the fixed user grouping scheme and the random user grouping scheme, the proposed scheme can effectively improve the system throughput.


Author(s):  
Dr. V. Arthi

4G Wireless communication systems have the inherent capability to foster the multimedia services in terms of bandwidth and data rate. These systems have very high integrity compared to the conventional wireless communication systems. It can fully support extended multimedia services with High Definition quality, audio and video files. Wireless internet and other broad band services provided superior quality signal transmission and reception. The degree of freedom enjoyed by the technology in terms of scalability and reliability is highly commendable. Any basic wireless transmitter sends information by varying the phase of the signal. In the receiver end, the desired signal can be decoded by appropriate decoding algorithm. The degradation occurs at the conventional receivers due to lack of Channel State Information. The efficiency of 4G system purely relies on the performance of receiver and is purely dependent on the synchronization of estimated instantaneous channel. In any wireless terminal, channel state information provides the in and around status of the channel. It provides the following parameters of the propagating signal (ie) Scattering, Fading and Attenuation. The dynamic estimation of channel state information can be obtained through Enhanced Least Squares channel estimation algorithm. It is based on Multi Carrier Filter Bank Transmission system. This  kind of dynamic estimation can be done with a set of well-known sequence of  coded unique bits .For a transmitter the information propagation is initiated in the form of frame bursts. It enhances the throughput of the system to the required level.


Author(s):  
Sambhavi Tiwari ◽  
Abhishek Abhishek ◽  
Shkehar Verma ◽  
K Singh ◽  
M Syafrullah ◽  
...  

2013 ◽  
Vol 2013 ◽  
pp. 1-6
Author(s):  
Hossein Khaleghi Bizaki ◽  
Morteza Khaleghi Hojaghan ◽  
Seyyed Mohammad Razavizadeh

This paper concentrates on the designing of a robust Tomlinson-Harashima Precoder (THP) over multiple-input multiple-output (MIMO) channels in wireless communication systems with assumption of imperfect channel state information (CSI) at the transmitter side. With the assumption that the covariance matrix of channel estimation error is available at the transmitter side, we design a THP that presents robustness against channel uncertainties. In the proposed robust THP, the transmit power is further minimized by using the Tilted constellation concept. This power minimization reduces the interchannel Interference (ICI) between subchannels and, furthermore, recovers some part of the THP's power loss. The bit error rate (BER) of the proposed system is further improved by using a power loading technique. Finally, the simulation results compare the performance of our proposed robust THP with a conventional MIMO-THP.


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