scholarly journals Concurrent Modified Constant Modulus Algorithm and Decision Directed Scheme With Barzilai-Borwein Method

2021 ◽  
Vol 15 ◽  
Author(s):  
Tongtong Xu ◽  
Zheng Xiang ◽  
Hua Yang ◽  
Yun Chen ◽  
Jun Luo ◽  
...  
Keyword(s):  
Wireless Communication ◽  
Optimization Problems ◽  
Blind Equalization ◽  
Wireless Channel ◽  
Constant Modulus ◽  
Constant Modulus Algorithm ◽  
Step Size ◽  
Pilot Signal ◽  
Unconstrained Optimization Problems ◽  
Wireless Communications Systems

At present, in robot technology, remote control of robot is realized by wireless communication technology, and data anti-interference in wireless channel becomes a very important part. Any wireless communication system has an inherent multi-path propagation problem, which leads to the expansion of generated symbols on a time scale, resulting in symbol overlap and Inter-symbol Interference (ISI). ISI in the signal must be removed and the signal restores to its original state at the time of transmission or becomes as close to it as possible. Blind equalization is a popular equalization method for recovering transmitted symbols of superimposed noise without any pilot signal. In this work, we propose a concurrent modified constant modulus algorithm (MCMA) and the decision-directed scheme (DDS) with the Barzilai-Borwein (BB) method for the purpose of blind equalization of wireless communications systems (WCS). The BB method, which is two-step gradient method, has been widely employed to solve multidimensional unconstrained optimization problems. Considering the similarity of equalization process and optimization process, the proposed algorithm combines existing blind equalization algorithm and Barzilai-Borwein method, and concurrently operates a MCMA equalizer and a DD equalizer. After that, it modifies the DD equalizer's step size (SS) by the BB method. Theoretical investigation was involved and it demonstrated rapid convergence and improved equalization performance of the proposed algorithm compared with the original one. Additionally, the simulation results were consistent with the proposed technique.

scholarly journals Concurrent Modified Constant Modulus Algorithm and Decision Directed Scheme with Barzilai-Borwein Method

2020 ◽  
Author(s):  
Tongtong Xu ◽  
Zheng Xiang
Keyword(s):  
Theoretical Analysis ◽  
Gradient Method ◽  
Optimization Problems ◽  
Constant Modulus ◽  
Constant Modulus Algorithm ◽  
Step Size ◽  
Unconstrained Optimization Problems ◽  
Communications Systems ◽  
Simulation Results ◽  
Wireless Communications Systems

Abstract In this work, concurrent modified constant modulus algorithm and decision-directed scheme with the Barzilai-Borwein method is proposed for blind equalization of wireless communications systems. The Barzilai-Borwein method, the two-step gradient method, is usually used to solve multidimensional unconstrained optimization problems. The proposed algorithm concurrently operates a modified constant modulus algorithm equalizer and a decision directed equalizer, it then adaptively adjusts the step size of the decision directed equalizer using Barzilai-Borwein method. Theoretical analysis is provided to illustrate that the proposed algorithm has a faster convergence speed, and better equalization performance than the original one. Simulation results support the new proposed technique.

New Hybrid Blind Equalization Algorithms

2012 ◽  
Vol 182-183 ◽  
pp. 1810-1815
Author(s):  
Shun Lan Liu ◽  
Lin Wang
Keyword(s):  
Blind Equalization ◽  
Convergence Speed ◽  
Variable Step Size ◽  
Constant Modulus ◽  
Computation Complexity ◽  
Constant Modulus Algorithm ◽  
Step Size ◽  
Variable Step ◽  
Simulation Results ◽  
The Cost

A novel decision-directed Modified Constant Modulus Algorithm (DD-MCMA) was proposed firstly. Then a constellation matched error (CME) function was added to the cost function of DD-MCMA and CME-DD-MCMA algorithm was presented. Furthermore, we improve the CME-DD-MCMA by replacing the fixed step with variable step size, that is VSS-CME-DD-MCMA algorithm. The simulation results show that the proposed new blind equalization algorithms can tremendously accelerate the convergence speed and achieve lower residual inter-symbol interference (ISI) than MCMA, and among the three proposed algorithms, VSS-CME-DD-MCMA has the fastest convergence speed and the lowest residual ISI, but it has the largest computation complexity.

Modified constant modulus algorithm based on bat algorithm

2021 ◽  
pp. 1-8
Author(s):  
Tongtong Xu ◽  
Zheng Xiang
Keyword(s):  
Communication Systems ◽  
Optimization Problems ◽  
Error Function ◽  
Bat Algorithm ◽  
Weight Vector ◽  
Wireless Channel ◽  
Constant Modulus ◽  
Constant Modulus Algorithm ◽  
Blind Channel Equalization ◽  
Almost All

In this work, modified constant modulus algorithm based on bat algorithm is proposed for wireless sensor communications systems. The bat algorithm is a swarm intelligence optimization algorithm, which mainly used to solve optimization problems. The proposed algorithm focused on modified constant modulus algorithm, which is also applicable to the constant modulus algorithm. The error function of blind equalization algorithm is used as the evaluation function of the bat algorithm, and then the initial value of the weight vector is calculated adaptively by the bat algorithm. Theoretical analysis is provided to illustrate that the proposed algorithm has a faster convergence speed than the original one and is suitable for almost all blind channel equalization algorithms. The simulation results support the newly proposed improved algorithm. The proposed algorithm could be applied to some more complex wireless channel environments to improve the reception performance of sensor communication systems.

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