System and method for preamble detection in MIMO narrowband power line communications

摘要

A PLC network system and method operative with OFDM for generating MIMO frames with suitable preamble portions configured to provide backward compatibility with legacy PLC devices and facilitate different receiver tasks such as frame detection and symbol timing, channel estimation and automatic gain control (AGC), including robust preamble detection in the presence of impulsive noise and frequency-selective channels of the PLC network. A PLC device may include a delayed correlation detector and a cross-correlation detector operating in concert to facilitate preamble detection in one implementation.

主权项

1. A preamble detector for use with a power line communications (PLC) device operative to receive data in a PLC network using an Orthogonal Frequency Division Multiplexing (OFDM) modulation scheme, comprising:
a delayed correlation detector configured to determine an initial estimate of a preamble start in a received PLC signal stream; anda cross-correlation detector configured to, responsive to a search range around the initial estimate of the preamble start, determine a final estimate thereof based on cross-correlating against a known preamble sequence that is indicative of a start of a PLC frame in the received PLC signal stream;
wherein the received PLC signal stream includes a preamble portion operative according to a legacy PLC data transmission standard comprising IEEE 1901.2 standard and further wherein the preamble portion comprises 8 SYNCP symbols followed by a full SYNCM symbol and a half SYNCM symbol, each symbol including a plurality of OFDM samples; wherein the delayed correlation detector is operative to: select a sliding window that spans a known number of SYNCP and SYNCM symbols; move the sliding window over the received PLC signal stream one sample at a time and calculate, for each window placement, a set of delayed correlations based on a select correlation order; add absolute values of the delayed correlations together to obtain a total correlation value for each window placement over the received PLC signal stream; and apply a threshold against the total correlation values and select a sample index having maximum correlation as the initial estimate of the preamble start based on a maximization length parameter.