Frequency Offset Estimation Scheme in the Presence of Time-Varying DC Offset for OFDM Direct Conversion Receivers
نویسندگان
چکیده
This paper presents a frequency offset estimation scheme for Orthogonal Frequency Division Multiplex (OFDM) direct conversion receivers. The key idea is to use a differential filter for reduction of DC offset. Frequency offset is estimated in the presence of time-varying DC offset. In order to overcome the varying DC levels under automatic gain control (AGC) circuits, a threshold level is set for the output of the differential filter. The proposed compensation scheme offers superior frequency offset estimation when compared with a conventional scheme with a high pass filter. key words: direct conversion, OFDM, DC offset, frequency offset, training sequence
منابع مشابه
IQ Imbalance Estimation Scheme in the Presence of DC Offset and Frequency Offset in the Frequency Domain
Direct conversion receivers in orthogonal frequency division multiplexing (OFDM) systems suffer from direct current (DC) offset, frequency offset, and IQ imbalance. We have proposed an IQ imbalance estimation scheme in the presence of DC offset and frequency offset, which uses preamble signals in the time domain. In this scheme, the DC offset is eliminated by a differential filter. However, the...
متن کاملPreamble-Assisted Estimation for Frequency-Dependent I/Q Mismatch in Direct-Conversion OFDM Receivers
In direct-conversion orthogonal frequency division multiplexing (OFDM) receivers, the impact of frequency-dependent I/Q mismatch (IQ-M) with carrier frequency offset (CFO) must be considered. A preamble-assisted estimation is developed to circumvent the frequencydependent IQ-M with CFO. The results of a simulation and an experiment show that the proposed method could provide good estimation eff...
متن کاملBlind estimation of carrier frequency offset, I/Q imbalance and DC offset for OFDM systems
Sensitivity to carrier frequency offset (CFO) is one of the biggest drawbacks of orthogonal frequency division multiplexing (OFDM) system. A lot of CFO estimation algorithms had been studied for compensation of CFO in OFDM system. However, with the adoption of direct-conversion architecture (DCA), which introduces additional impairments such as dc offset (DCO) and in-phase/quadrature (I/Q) imba...
متن کاملEvaluation of LPF and PCLPF and Development of a Novel Method to Solve DC Offset Problem in Vector Control of Induction Motors
Stator flux oriented vector control of induction motor (IM) drives for speed sensorless control has several advantages. But the application of a pure integrator for the flux estimation is difficult due to the presence of measurement noise and dc offset. To overcome these problems, some have used a programmable cascaded low pass filter (PCLPF). In this paper, it is shown that some problems still...
متن کاملPerformance Analysis of Alamouti Space Time Coded OFDM under various Receiver Impairments
In this paper we present an analytical approach to evaluate the M-QAM symbol error rate (SER) of Alamouti space time coded OFDM direct conversion receivers subject to carrier frequency offset (CFO), channel estimation errors, outdated channel state information, limited ADC resolution and flat receiver I/Q imbalance in Rayleigh time and frequency selective fading channels. The SER is numerically...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید
ثبت ناماگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید
ورودعنوان ژورنال:
- IEICE Transactions
دوره 90-B شماره
صفحات -
تاریخ انتشار 2007