Contents
What is Frequency Offset Estimation?
The performance of OFDM system is very sensitive to CFO, which introduces inter-carrier interference (ICI). In cyclic prefix (CP) based estimation, the CFO can be found from the phase angle of the product of CP and corresponding rear part of the OFDM symbol.
What is frequency offset in LTE?
The Carrier Frequency Offset (CFO) occurs in an LTE-OFDM system due to the mismatched frequencies on the received signal and the local oscillator at the receiver.
What is meant by frequency offset?
In radio engineering, a frequency offset is an intentional slight shift of broadcast radio frequency (RF), to reduce interference with other transmitters.
What is Symbol time offset?
Abstract—Symbol timing offset (STO) can result in intersymbol interference (ISI) and a rotated phase which value is proportional to the subcarrier index at the FFT output in an OFDM receiver.
How do I find carrier frequency?
The carrier frequency can then be calculated as 2X99/100×1/100 which approximates to 1 in 50. Thus a rough approximation of the carrier frequency can be obtained by doubling the square root of the disease incidence. For an X-linked disorder the frequency of affected males equals the frequency of the mutant allele, q.
What is symbol time offset?
How do you calculate carrier frequency offset?
Example. If the TX oscillator runs at a frequency that is 20 ppm above the nominal frequency and if the RX oscillator is running at 20 ppm below, then the received baseband signal will have a CFO of 40 ppm. With a carrier frequency of 5.2 GHz in this standard, the CFO is up to ±208 kHz.
What generates the final carrier frequency?
What generates the final carrier frequency? Explanation: An oscillator, in most applications a crystal oscillator, generates the final carrier frequency. A modulator simply adds the information signal and an antenna transmits the signal.
How do I know what frequency my carrier is?
When to use St for frequency offset estimation?
The ST is mainly used for frame synchronization, Automatic Gain Control (AGC), antenna selection (in case of selection diversity), and coarse frequency offset estimation. In this paper we assume that synchronization has been achieved and frequency offset estimation is performed using the last 5 parts,
Why is the sign change used in frequency offset estimation?
In [6] a new training sequence is proposed which consists of identical parts with a sign change. The sign change is to improve time synchronization. The frequency offset estimation scheme in [6] is that of [4] with modifications to accommodate the sign change in the identical parts.
How to increase the range of frequency estimation?
Frequency estimation schemes are proposed in [4], [5] that rely on dividing the symbol into several identical shorter parts to increase the estimation range. In [6] a new training sequence is proposed which consists of identical parts with a sign change. The sign change is to improve time synchronization.
How to estimate the effect of carrier and sampling frequency offset?
Abstract— This paper shows how to utilize the Short Training Sequence, Long Training Sequence and Pilot Subcarriers, of the IEEE 802.11a frame, to estimate and equalize the effect of both carrier and sampling frequency offset. To reduce cost the equalization process is performed digitally.