Multiple Doppler frequency offsets compensation technique for high-mobility OFDM uplink

2013 ◽  
Author(s):  
Wei Guo ◽  
Pengcheng Mu ◽  
Qinye Yin ◽  
Hui-Ming Wang
Keyword(s):  
High Mobility ◽  
Doppler Frequency ◽  
Compensation Technique ◽  
Frequency Offsets

scholarly journals Method of Doppler Frequency Spread Estimation for High-Mobility OFDM Systems

2015 ◽  
Vol 2015 ◽  
pp. 1-6 ◽  
Author(s):  
Feng Zhao ◽  
Xihong Sun
Keyword(s):  
Autocorrelation Function ◽  
Orthogonal Frequency Division Multiplexing ◽  
Estimation Error ◽  
High Mobility ◽  
Doppler Frequency ◽  
Estimation Algorithm ◽  
Least Square ◽  
Ofdm Systems ◽  
Frequency Spread ◽  
Spread Estimation

A method of Doppler frequency spread (DFS) estimation algorithm is discussed which is suitable for high-mobility Orthogonal Frequency Division Multiplexing (OFDM) systems. DFS is a main factor which may mitigate the performance of system. The proposed method is based on autocorrelation function algorithm of received signal which utilizes cyclic prefix (CP) to estimate Doppler spread. The estimation algorithm uses least square (LS) method between the autocorrelation function of received signal and the zero-order Bessel function which is approximated by the expansion of power series. Then the estimation bias is analyzed and using polynomial fitting method can effectively correct estimation error at different DFS, respectively. Compared with the previously proposed method, the estimation performance of DFS in the proposed method has better performance. Simulation results show that when sufficient elements are used, the proposed scheme can effectively estimate DFS and can be applied into high-mobility OFDM systems.

scholarly journals Performance evaluation of high mobility OFDM channel estimation techniques

2020 ◽  
Vol 10 (3) ◽  
pp. 2562
Author(s):  
Maryam K. Abboud ◽  
Bayan M. Sabbar
Keyword(s):  
Orthogonal Frequency Division Multiplexing ◽  
Performance Test ◽  
High Mobility ◽  
Doppler Frequency ◽  
Multipath Fading ◽  
Least Square ◽  
Mobile Systems ◽  
Estimation Methods ◽  
Ofdm Systems ◽  
Ofdm Symbol

In wireless communication, Orthogonal Frequency Division Multiplexing (OFDM) has been adopted due to its robustness to multipath fading and high data rate transmissions. At the other hand, the performance of OFDM systems severely degraded due to multi-path fading and Doppler frequency shifts in mobile systems, which causes inter-carrier-interference (ICI). Thus, Estimation of channel parameters is required at the receiver using a pre designed estimator where pilot tones are inserted in each OFDM symbol. In this paper, a random pilot data are generated and inserted in each OFDM symbol at equally spaced locations. The performance test of Least Square (LS) and Linear Minimum Mean Square (LMMSE) estimation methods are proposed with Discrete Fourier Transform (DFT) based on both LS and LMMSE, where different ITU channel models are considered in order to compare their performance for data transmission in high mobile systems with different Doppler frequencies exceeds 200 Hz and minimal number of pilots.

scholarly journals Method for determining of the distance to the object in the hyperbolic navigation system via doppler frequency offsets

2022 ◽  
pp. 40-46
Author(s):  
V. V. Legkostup ◽  
V. E. Markevich
Keyword(s):  
Navigation System ◽  
Classical Method ◽  
Doppler Frequency ◽  
Frequency Offsets ◽  
Guidance Problem

In this paper, a method for estimating the distance to the object guided along a hyperbola to a target using a bistatic hyperbolic navigation system on a plane is given. At the same time, to solve the guidance problem, the number of required navigation positions is reduced by one in comparison with the classical method of hyperbolic navigation. However, in the guidance algorithms, it is still required to estimate the distance of the targeted object from the center of the base, the methods of obtaining which are considered in the work.

scholarly journals Multiple-Observation-Based Robust Channel and Doppler Estimation in High Mobility Applications

2013 ◽  
Vol 2013 ◽  
pp. 1-8
Author(s):  
Md. Jahidur Rahman ◽  
Jiaxin Yang
Keyword(s):  
Channel Estimation ◽  
Mobile Applications ◽  
Communication Systems ◽  
High Mobility ◽  
Doppler Frequency ◽  
Rapid Variation ◽  
Channel Parameters ◽  
A New Technique ◽  
Time Varying Channel ◽  
Estimation Of Time

Channel estimation is a challenging task, especially in high mobility applications due to the rapid variation of the propagation environment. This paper presents a new technique that exploits past channel impulse responses (CIRs) in order to trace and compensate Doppler frequency in mobile applications, enabling robust estimation of time-varying channel. Based on the fact that channel taps at different time instants can be fitted with a sinusoidal wave, a joint estimator is proposed to estimate the channel parameters. Therefore, the efficiency of the channel estimation can be improved and stringent delay requirements for the communication systems can also be satisfied. Simulation results show that system performance in terms of bit error rate (BER) is significantly improved with the proposed algorithm.

Cooperative Access Architecture for High Speed Railway

2011 ◽  
Vol 403-408 ◽  
pp. 2839-2842 ◽  
Author(s):  
Fang Dong ◽  
Jun Biao Liu ◽  
Xiao Hui Hu
Keyword(s):  
Frequency Shift ◽  
High Speed ◽  
High Mobility ◽  
Network Connectivity ◽  
Doppler Frequency ◽  
Doppler Frequency Shift ◽  
Broadband Communication ◽  
High Speed Railway ◽  
Fast Handoff ◽  
Definition Of

With the great demand for broadband communication in high speed railway, new access technologies should be adapted to high mobility which brings Doppler frequency shift and fast handoff. The definition of cooperative range is presented and its influence on network connectivity is studied. The result shows that cooperation can greatly extend a wireless user’s communication range. A novel scheme of cooperative access architecture is proposed to support high-speed users with broadband communication.

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