Receiver for a home phone-lines LAN system

Details Receiver for a home phone-lines LAN system Receiver for a home phone-lines LAN system

2000-04-18

2004-04-13

Chin, Stephen (Department: 2634)

Pulse or digital communications

Systems using alternating or pulsating current

Plural channels for transmission of a single pulse train

C375S343000, C375S368000

Reexamination Certificate

active

06721365

ABSTRACT:

BACKGROUND OF THE INVENTION
1. Field of Invention
The present invention relates to a receiver for a LAN system and, more particularly, to a receiver installed in a computer for receiving signals transmitted in a home phone-lines LAN system and distinguishing a valid signal and a collision backoff signal from noises in real time.
2. Related Art
Along with the prospering electronic IC industries and information technologies in recent years, network systems play an important role in daily life. In particular, because the phone-lines in home have already installed for general telephone network, it is convenience to use the same home phone-lines as the transmission medium in home local area network (hereinafter “HLAN”) systems. Each computer in the HLAN system can install a receiver to receive the signals transmitted via the phone lines.
As shown in
FIG. 1
, a conventional receiver in a home phone-lines LAN system compliant with the HomePNA 2.0 specification comprises a QAM (quadrature amplitude modulation) demodulator
101
for providing the “I” and “Q” signals from signal frames; an equalizer
102
for compensating the “I” and “Q” signals for the distortion caused by transmission; a deconstellation
103
for converting the compensated “I” and “Q” signals into data signal D; a detector
104
for distinguishing the “valid signal frame” and “collision backoff signal frame” from noises and other interference: and a data reading module
105
for reading in subsequent data signal when the signal frame is a valid signal frame.
However, in a conventional receiver described above, because the detector
104
is connected to the deconstellation
103
, it can distinguish the valid signal frame and the collision backoff signal frame from noises only after the demodulation by the QAM
101
, the distortion compensation by the equalizer
102
, and the conversion to a data signal D by the deconstellation
103
. Nevertheless, when the received signal RS contain too much interference, it will take longer time for the equalizer
102
to compensate for the distortion and thus the system might not be able to receive the valid signal in time.
SUMMARY OF THE INVENTION
In view of the foregoing, it is an object of the present invention to provide a receiver for a home phone-lines LAN system containing a signal match filter module which detects a received signal and determines whether received signal is a valid signal, collision backoff signal, or noise in real time.
In accordance with an aspect of the present invention, the receiver for a home phone-lines LAN system of the present invention comprises a QAM demodulator for demodulating the received signal into “I” and “Q” signals; an equalizer connected to the QAM for compensating the “I” and “Q” signals for the distortion; a deconstellation connected to the equalizer for converting the compensated “I” and “Q” signals into data signal; a signal match filter module connected to the QAM demodulator for performing match operation to generate a match value; a detector connected to the signal match filter module for detecting the match value and outputting a frame type; and a data reading module connected to both the deconstellation and the detector for reading the transmission data when the frame type is a valid signal frame.
According to the receiver for a home phone-lines LAN system of the present invention, the signal match filter module comprises an adder connected to the QAM demodulator for adding up the “I” and “Q” signals to generate a combined signal; and at least one set of cross-correlator for performing correlation operation on the combined signal and outputs a match value.
According to the receiver for a home phone-lines LAN system of the present invention, each cross-correlator comprises a plurality of shift buffers for shifting the combined signal; a plurality of multipliers having an input to receive the value stored in each shift buffer for multiplying the value and an identification value; and an adder for adding up the output values of the plurality of multipliers to generate the match value.
According to the receiver for a home phone-lines LAN system of the present invention, each cross-correlator comprises a RAM module for storing the data of combined signal circularly; a ROM module for storing the data of identification value; a multiplier for multiplying the data output from the RAM module and the data output from the ROM module; an accumulator for accumulating the value output from the multiplier; and a controller for controlling the action of the signal match filter module.


REFERENCES:
patent: 5251233 (1993-10-01), Labedz et al.
patent: 5970092 (1999-10-01), Currivan
patent: 6396953 (2002-05-01), Abbey

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