A Fast Adaptive Transmit Power and Bit Allocation in OFDM System

2013 ◽  
Vol 765-767 ◽  
pp. 444-447
Author(s):  
Juan Wen ◽  
Qi Ming Tian
Keyword(s):  
Theoretical Analysis ◽  
Bit Error Rate ◽  
Error Rate ◽  
Bit Allocation ◽  
Ofdm System ◽  
Transmit Power ◽  
Allocation Algorithm ◽  
Bisection Algorithm ◽  
Simulation Results ◽  
Adaptive Transmit Power

In this paper, we propose a fast and optimal adaptive transmit power and bit allocation algorithm, which is called Bisection Searching Level (BSL) for wireless OFDMA systems. The algorithm aims at maximization of data rate under the constraints of total transmit power and bit error rate (BER). BSL is based on water pouring approach, and adopt bisection algorithm to find the water pouring level under discrete bit restriction. Both theoretical analysis and simulation results demonstrate the optimality of our proposed algorithm.

Adaptive Bit Allocation Algorithm for OFDM System

2014 ◽  
Vol 989-994 ◽  
pp. 2161-2164
Author(s):  
Wei Wei ◽  
Wen Dong An
Keyword(s):  
Greedy Algorithm ◽  
Bit Error Rate ◽  
Data Transmission ◽  
Transmission Rate ◽  
Bit Allocation ◽  
Total Power ◽  
Ofdm System ◽  
Allocation Algorithm ◽  
The Greedy Algorithm ◽  
Number Of Iterations

For the greedy algorithm required a large number of iterations, this paper proposed one adaptive bit allocation algorithm based on Hughes-Hartogs algorithm which was improved greedy algorithm .Under the constraint of bit error rate and data transmission rate, the algorithm first used the Chow algorithm to allocate some of the bits, and then used the greedy algorithm to allocate the remaining bits. When minimize the total power by this algorithm, the iterations of this algorithm were significantly less than the greedy algorithm. By computer simulation, the results showed that performance of this algorithm was very close to the greedy algorithm, and the number of this algorithm’s iterations was 7.4%~34% of the greedy algorithm.

Simulation Implementation and Analysis of the OFDM Modulated by MPSK and M-QAM

2014 ◽  
Vol 543-547 ◽  
pp. 2221-2224
Author(s):  
Li Ming Yang ◽  
Jia Guo ◽  
Hong Wei Ding ◽  
Yong Wang ◽  
Yi Fan Zhao
Keyword(s):  
Bit Error Rate ◽  
Error Rate ◽  
Ofdm System ◽  
Channel Simulation ◽  
Rayleigh Channel ◽  
Simulation Results

Simulated for OFDM system modulated by 16PSK, 16QAM and 64QAM, and then we compared and analyzed their performance in the Rayleigh channel and 2 paths Rayleigh channel. Simulation results show that under the same conditions, Bit Error Rate (BER) of MQAM modulation system is lower than the same order MPSKs

A New SLNR-Based Precoding for Multiuser MIMO Downlinks

2014 ◽  
Vol 644-650 ◽  
pp. 4066-4071
Author(s):  
Xin Min Li
Keyword(s):  
Bit Error Rate ◽  
Error Rate ◽  
Base Station ◽  
Semidefinite Relaxation ◽  
Constraint Condition ◽  
Multiuser Mimo ◽  
Power Constraint ◽  
Transmit Power ◽  
Simulation Results

A new SLNR-based precoding is proposed for multiuser MIMO downlinks, which pursues the goal that minimizes total transmit power under each user’s SLNR constraint. The goal problems can be successfully solved by using semidefinite relaxation (SDR) techniques, and power constraint condition added in goal problems can efficiently reduce total transmit power of the base station. Simulation results show that our proposed scheme is almost feasible for users with one antenna, and it has better bit error rate (BER) and lower total transmit power than the maximal-SLNR based precoding method, when it satisfies large SLNR thretholds.

Energy-Efficient Joint Power Allocation and Relay Selection in Bit Error Rate Constrained Two-Way Relay Network

2015 ◽  
Vol 7 (4) ◽  
pp. 1-14
Author(s):  
Rashi Mehrotra ◽  
Ranjan Bose
Keyword(s):  
Power Consumption ◽  
Power Allocation ◽  
Bit Error Rate ◽  
Error Rate ◽  
Energy Efficient ◽  
Relay Selection ◽  
Relay Network ◽  
Transmit Power ◽  
Selection Scheme ◽  
Simulation Results

In this paper, the authors have proposed energy efficient power allocation and relay selection scheme in a two-way amplify-and-forward (AF) relay under bit error rate (BER) constrained network. They have derived an expression for the overall BER for Rayleigh fading channel. Based on minimum power consumption in the network, the authors have addressed the problem of power allocation by converting geometric programming to a convex optimization problem. A closed form solution of power allocation is found, which aims at minimizing total transmit power for the overall BER constrained network. The authors have evaluated minimum total transmit power for two-way AF relay network. Based on minimum total transmit power, a novel relay selection scheme has been proposed. Simulation results demonstrate that the proposed two-way power allocation and relay selection scheme can significantly minimize power consumption under BER constrained network as compared to the existing relay transmission. The proposed power allocation scheme gives 3 dBW gain than one-way relay transmission. The proposed relay selection method also outperforms the random relay selection by 24 dBW. The simulation results are corroborated with the analytical result

An SC-FDMA Channel Estimation Algorithm Research Based on Pilot Signals

2013 ◽  
Vol 347-350 ◽  
pp. 1682-1687
Author(s):  
Jian Bin Xue ◽  
Song Bai Li
Keyword(s):  
Theoretical Analysis ◽  
Channel Estimation ◽  
Bit Error Rate ◽  
Error Rate ◽  
Main Idea ◽  
Estimation Algorithm ◽  
Estimation Accuracy ◽  
Mean Square ◽  
Simulation Results ◽  
Lte Uplink

SC-FDMA as LTE uplink main technology has been widely studied,at the same time, channel estimation around such technology is becoming hot,In order to research and increase channel estimation accuracy of LTE uplink system,an algorithm based on pilot is proposed in this paper,this algorithms main idea is,by setting a certain bit error rate,choosing some proper data after channel estimation done under R-LS and M-MMSE, combining the chosen data and former block pilot and increasing pilot number to do channel estimation again, system bit error rate and mean square error results can be got by simulation;at last,the theoretical analysis and simulation results show that this algorithm really can make the channel estimation accuracy improved and bit error rate decreased.

Construction and Analysis on a New Concatenation Code for Optical Communications

2014 ◽  
Vol 543-547 ◽  
pp. 2266-2269
Author(s):  
Jian Guo Yuan ◽  
Yang Tian ◽  
Jie Zhang ◽  
Liang Bo Shu
Keyword(s):  
Theoretical Analysis ◽  
Error Correction ◽  
Bit Error Rate ◽  
Error Rate ◽  
Optical Communications ◽  
Coding Gain ◽  
The Third ◽  
Simulation Results

Based on the theoretical analysis of both the characteristics for the concatenation code and the two concatenation code-types in ITU-T G.975.1, a new RS(255,223) + BCH(2040,1930) concatenation code for optical communications is constructed and analyzed. The simulation results show that this new concatenation code, compared with the RS(255,239)+CSOC(k0/n0=6/7,J=8) code in ITU-T G.975.1, had a lower redundancy and the better error-correction performance. Furthermore, at the third iteration and at the bit error rate (BER) of 10-12, its net coding gain (NCG) was respectively 0.46 dB and 0.43 dB more than that of RS(255,239)+CSOC(k0/n0=6/7,J=8) code and BCH(3860,3824)+BCH(2040,1930) code in ITU-T G.975.1. Therefore, the constructed RS(255,223)+BCH(2040,1930) concatenation code can be better suitable for optical communications.

scholarly journals Bit error rate of DCO-OFDM system over an indoor diffuse link

2017 ◽  
Vol 1 (T4) ◽  
pp. 163-171
Author(s):  
Khoa Le Dang ◽  
Anh Quoc Huynh ◽  
Phuong Huu Nguyen ◽  
Linh Vu Nguyen ◽  
Hiroshi Ochi
Keyword(s):  
Bit Error Rate ◽  
Error Rate ◽  
Orthogonal Frequency Division Multiplexing ◽  
Optical Wireless Communication ◽  
Frequency Division ◽  
Optical Wireless ◽  
Ofdm System ◽  
Simulation Results ◽  
First Time ◽  
Good Agreement

The technique named DC biased orthogonal frequency division multiplexing (DCO-OFDM) is the most popular method in optical wireless communication system. In this article, we describe for the first time an exact numerical computation for the bit error rate (BER) of DCOOFDM over an indoor diffuse link. The simulation model is also provided, and simulation results showed a good agreement with theoretical analysis.

scholarly journals Performance Enhancement of Coherent Optical OFDM System Using LMS Algorithm

2020 ◽  
Vol 1 ◽  
pp. 1-5
Author(s):  
Manisha Bharti
Keyword(s):  
Phase Noise ◽  
Bit Error Rate ◽  
Error Rate ◽  
Orthogonal Frequency Division Multiplexing ◽  
Performance Enhancement ◽  
Lms Algorithm ◽  
Frame Structure ◽  
Least Mean Square ◽  
Ofdm Systems ◽  
Ofdm System

Instability of the local oscillator causes phase noise – a phenomenon that is a disadvantage and is considered to be a major obstacle in the functioning of coherent optical orthogonal frequency division multiplexing (CO-OFDM) systems. An attempt has been made in this paper to reduce the effects of common phase errors generated by phase noise. In this paper, a least mean square (LMS) based algorithm is proposed for estimation of phase noise. Using this proposed algorithm, the major problem of phase ambiguity caused by cycle slip is avoided and the bit error rate is greatly improved. Further, there is no requirement for modifying the frame structure of OFDM using this algorithm. A CO-OFDM system with the 8-PSK technique is used to implement the algorithm concerned. Furthermore, the algorithm, using the 8-PSK modulation technique, is analyzed and compared with the existing QPSK technique and with other algorithms. The investigations reveal that 8-PSK outperforms existing LMS algorithms using other techniques and significantly reduces the bit error rate.

scholarly journals PAPR Reduction of FBMC Signals Based on Uniform and Linear PDF Companding Schemes

2021 ◽  
Author(s):  
Srinivas Ramavath ◽  
Umesh Chandra Samal
Keyword(s):  
Theoretical Analysis ◽  
Bit Error Rate ◽  
Error Rate ◽  
Filter Bank ◽  
Phase Error ◽  
Average Power ◽  
Signal Amplitude ◽  
Papr Reduction ◽  
Basic Model ◽  
Filter Bank Multicarrier

Abstract In this paper, two new companders are designed to reduce the ratio of peak to average power (PAPR) experienced by filter bank multicarrier (FBMC) signals. Specifically, the compander basic model is generalized, which alter the distributed FBMC signal amplitude peak. The proposed companders design approach provides better performance in terms of reducing the PAPR, Bit Error Rate (BER) and phase error degradation over the previously existing compander schemes. Many PAPR reduction approaches, such as the µ-law companding technique, are also available. It results in the formation of spectrum side lobes, although the proposed techniques result in a spectrum with fewer side lobes. The theoretical analysis of linear compander and expander transform for a few specific parameters are derived and analyzed. The suggested linear companding technique is analytically analysed using simulations to show that it efficiently decreases the high peaks in the FBMC system.

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