Fractional carrier frequency offset estimator and method of estimating fractional carrier frequency offset between transmitter and receiver

Abstract

Fractional carrier frequency offset estimators and related methods are disclosed. The invention may be particularly applied in WiMAX systems. The disclosed method of estimating fractional carrier frequency offset between a transmitter and a receiver includes calculating a first delay correlation based on a first and a second preamble repetitions included in a received signal, processing the phaseof the first delay correlation to compensate for a phase rotation of the first delay correlation, and estimating the fractional carrier frequency offset by multiplying a processed phase value, generated after the step of processing the phase of the first delay correlation, by a predetermined value.

Description

technical field [0001] The present invention relates to a device and method for estimating fractional carrier frequency offset between transmitter and receiver. The present invention is generally applied to Orthogonal Frequency Division Multiplexing (OFDM) related systems, including Orthogonal Frequency Division Multiplexing Access (OFDMA), such as the Global Interoperability of Microwave Access Technology (Worldwide Interoperability for Microwave Access, WiMAX). Background technique [0002] figure 1 A wireless communication system 100 includes a transmitter 102 and a receiver 104 . The transmitter 102 sends a signal The signal s(t) to be transmitted is mixed, and the mixed signal is transmitted by an antenna 106 . The receiver 104 utilizes the antenna 108 to receive the signal transmitted by the transmitter 102, and converts it into a signal mixing. In this specification, the signal r(t) mixed by the receiver 104 is called a received signal, and its value is as fol...

AI Technical Summary

Problems solved by technology

However, due to coding issues, the preamble repetition codes of the WiMAX system are not identical to each other like the WLAN system.

The received signal r(t) of the WiMAX system has three preamble repetition codes, but the signal sampled at the receiving end with a 2-fold or 4-fold frequency do not have exactly the same three-segment repetition codes, which will result in a gap between the preamble repetition codes. Rotational phase exists for delay correlation

Taking the first sector as an example, in the received signal, the delay correlation z between the first and second preamble repetition codes 12 for Compared with Equation 1, the delay dependence z for this first sector 12 Also includes rotation phase Similarly, in the second and third sectors, the above-mentioned delay correlation z 12 The rotation phases that exist are and The formula 2 disclosed in patent case U.S. 5,732,113 cannot overcome the problem of rotational phase

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