Saankhya Labs Pvt. Ltd.

Tamiras Per Pte. Ltd., LLC

S Harish Krishnan

Parag Naik

Gururaj Padaki

Subrahmanya Kondageri Shankaraiah

Shrinivas Subramania Bhat

Saurabh Mishra

A system and method for reducing implementation complexity for estimation of a Carrier Frequency Offset (CFO) and a Symbol Timing Offset (STO) for an input signal for spectrally shaped multiple communication standards. The system is implemented by replacing multiplier with shifters. The system includes a CFO estimation block, a STO estimation block, and a band extraction block that extracts a lower band edge and an upper band edge of the input signal. The STO estimation block includes (i) a sample error generation block that computes a sampling timing error value, and (ii) a Phase Lock Loop block that estimates a frequency error and a phase error corresponding to the sampling timing error value. The CFO estimation block includes (i) a carrier offset error generation block that generates a carrier offset error value, and (ii) a leaky average block for performing a filter operation.

Method and system for reliable CFO and STO estimation in the presence of tuner induced impairment

A receiver and method of detecting a guard interval estimate accurately by performing an Nth order polynomial based non-linear quantization on a pre-estimated guard interval in a received Orthogonal Frequency Division Multiplexing (OFDM) signal in a receiver is provided. The pre-estimated guard interval is obtained by performing normalized auto-correlation on the received OFDM signal. The method includes (i) performing a rounding operation on (a) one or more mcoefficient of the polynomial and (b) the pre-estimated guard interval to obtain an indexing parameter 'k', and detecting the guard interval estimate based on (i) a value of k, and (ii) a guard interval from one or more guard intervals that are stored in a look up table. The guard interval estimate is detected in accordance with an equation: {tilde over (L)}=L[k&#x2212;4], where 'L' is the guard interval stored in the look up table that corresponds to the value of k.

Schemes for detecting guard intervals in OFDM system

At a receiver incoming coded OFDM Symbol Data are passed through a Coarse Symbol Timing Synchronization module to determine the approximate start of the symbol. In one embodiment this is accomplished through correlation. The symbol is then passed through an FFT (2K or 8K, depending on the mode desired by the receiver). Since the Coarse Symbol Timing Synchronization module only determines an approximate start point of the symbol, a process of fine synchronization is used to adjust this approximate start point and determine a more accurate start point of the symbol. In this manner, the receiver is enabled to process COFDM symbols in DVB-T transmissions (where the symbols include a cyclic prefix to overcome echoes). One output of an FFT operation is magnitude. Magnitude is used for Channel Estimation (or Channel Correction). Another output of an FFT operation is phase discontinuity or rotations. Phase discontinuities are used in a fine synchronization process to determine the number of phase discontinuities. Phase discontinuity data of the symbol is passed through an N-Point FFT.

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Bengaluru, India

S Harish Krishnan