Effect of Channel Estimation Error on Coordinated Small-Cells with Block Diagonalization

2014 ◽  
Vol 556-562 ◽  
pp. 4501-4504
Author(s):  
Soo Young Shin ◽  
Toha Ardi Nugraha

This paper investigates the implementation of cooperative communication in small-cells network. Cooperative communication is some cells that in a network can work together, ex. joint transmit power and exchange resource allocation among them. Therefore, cooperative small-cells can be possible to add more multiple input multiple output (MIMO) antennas. But, channel state information (CSI) is required. In practice, perfect channel state information may not be perfect due to the real condition of the real environment such as delay, error, and etc. This paper illustrates cooperative small-cells under error model on the channel estimation. Our propose system is combined by implementing block diagonalization pre-coding and power allocation based on water-filling algorithm. As investigated by simulation results, our proposed coordinated small-cells showed good performances compare to previous algorithm either with perfect channel or with the error channel estimation.

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.


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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