Channel equalizing and carrier recovery system for home phoneline networking alliance receiver and method thereof

• US 7,194,027 B2
• Filed: 04/15/2003
• Issued: 03/20/2007
• Est. Priority Date: 06/15/2002
• Status: Expired due to Fees

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Kim, Jung-hoon, Hwang, Sung-hyun, Kim, Jae-woo, Park, Hyun-cheol, Kwon, Oh-sang, Yim, Chang-hyun
• Primary Examiner(s): PHU, PHUONG M
• Application Number:
  US10/413,663
• Publication Number:
  US 20030231708A1
• Time in Patent Office: 1,435 Days
• Field of Search: 375/231, 375/232, 375/233, 375/234, 375/295, 375/316, 375/350, 375/346, 375/299, 375/261, 708/322, 708/323, 370/509, 370/419, 329/306
• US Class Current: 375/233
• CPC Class Codes: H04L 2025/0342 QAM
• CPC Class Codes: H04L 2025/03764 only during predefined intervals
• CPC Class Codes: H04L 2027/0038 using an equaliser
• CPC Class Codes: H04L 2027/0055 single phase
• CPC Class Codes: H04L 2027/0067 Phase error detectors
• CPC Class Codes: H04L 25/03038 with a non-recursive structure H04L25/03031 takes precedence
• CPC Class Codes: H04L 27/0008 arrangements for allowing a transmitter or receiver to use more than one type of modulation negotiating modulation type for two-way transmission paths H04L5/1453

Abstract

A channel equalizing and carrier recovery system for home phoneline networking alliance (HomePNA) receiver and method thereof are provided. The channel equalizing system includes a frequency diverse quadrature amplitude modulation (FD-QAM) equalizer and a quadrature amplitude modulation (QAM) equalizer. The FD-QAM equalizer receives an FD-QAM signal, determines FD-QAM tap coefficients, and equalizes the FD-QAM signal using the FD-QAM tap coefficients. The QAM equalizer receives a QAM signal, determines QAM tap coefficients, and equalizes the QAM signal using the QAM tap coefficients. The QAM equalizer receives the FD-QAM signal and determines the QAM tap coefficients during a predetermined header period. The carrier recovery circuit includes a phase detector, a loop filter, and a numerically controlled oscillator (NCO). The phase detector uses a phase difference between a reception symbol and a decision signal of the reception symbol as an instantaneous phase difference when the reception symbol is a data symbol of an FD-QAM signal or a symbol of a QAM signal, uses “0” as the instantaneous phase difference when the reception symbol is a zero symbol of the FD-QAM signal, averages instantaneous phase differences during a predetermined period or time, and outputs the result of averaging. The loop filter filters the output signal of the phase detector. The NCO generates an oscillation signal having a variable phase in response to an output signal of the loop filter so that a phase error of a reception signal can be controlled.

Claims

1. An adaptive channel equalizing system for a home phoneline networking alliance (HomePNA) receiver, the channel equalizing system comprising:

a frequency diverse quadrature amplitude modulation (FD-QAM) equalizer for determining FD-QAM tap coefficients and equalizing an FD-QAM signal input into the adaptive channel equalizing system;

a quadrature amplitude modulation (QAM) equalizer for receiving the FD-QAM signal determines QAM tap coefficients during a predetermined header period, and continuously updating the QAM tap coefficients during a predetermined payload period to equalize the QAM signal upon receiving the QAM signal; and

a multiplexer electrically coupled to the FD-QAM equalizer and the QAM equalizer, the FD-QAM equalizer and the QAM equalizer being connected in parallel, the multiplexer for selecting one of an equalized FD-QAM signal and an equalized QAM signal for output as an equalizer output symbol.

2. The channel equalizing system of claim 1, wherein the FD-QAM equalizer and the QAM equalizer update the FD-QAM tap coefficients and the QAM tap coefficients, respectively, using a least mean square algorithm.

3. The channel equalizing system of claim 1, wherein the FD-QAM equalizer updates all of the FD-QAM tap coefficients at a predetermined symbol time and does not update the FD-QAM tap coefficients at a predetermined zero time.

4. The channel equalizing system of claim 1, wherein within the header period, the QAM equalizer updates even tap coefficients including a predetermined center tap coefficient among the QAM tap coefficients at a predetermined symbol time and the odd tap coefficients at a predetermined zero time when the center tap coefficient is an even tap coefficient, and updates odd tap coefficients including a predetermined center tap coefficient among the QAM tap coefficients at the symbol time and the even tap coefficients at the zero time when the center tap coefficient is an odd tap coefficient, and

during the payload period, the QAM equalizer updates all of the QAM tap coefficients for every symbol.

8. The channel equalizing system of claim 2, wherein the delta signal is generated according to a difference between a hard-decision signal of an output signal of the common equalizer and the output signal of the common equalizer.

5. An adaptive channel equalizing system for a home phoneline networking alliance (HomePNA) receiver, the channel equalizing system comprising:

a frequency diverse quadrature amplitude modulation (FD-QAM) equalizer for receiving an FD-QAM signal, determining FD-QAM tap coefficients, and equalizing the FD-QAM signal using the FD-QAM tap coefficients; and

a quadrature amplitude modulation (QAM) equalizer for receiving a QAM signal, determining QAM tap coefficients, and equalizes the QAM signal using the QAM tap coefficients, wherein the QAM equalizer receives the FD-QAM signal and determines the QAM tap coefficients during a predetermined header period,

wherein the FD-QAM equalizer and the QAM equalizer constitute a common equalizer, and the common equalizer operates at a speed two times faster than a predetermined symbol frequency so that the FD-QAM tap coefficients and the QAM tap coefficients are determined within a symbol period.

6. The channel equalizing system of claim 5, wherein the common equalizer determines the FD-QAM tap coefficients during ½

of each symbol period and determines the QAM tap coefficients during the remaining ½

of each symbol period.

7. The channel equalizing system of claim 5, wherein the common equalizer comprises:

at least two tap coefficient update blocks for adding previous FD-QAM tap coefficients to a predetermined update signal and adding previous QAM tap coefficients to another predetermined update signal to update the FD-QAM tap coefficients and the QAM tap coefficients and storing the updated FD-QAM and QAM tap coefficients; and

an update signal generator for selecting one among a signal 0 and a predetermined delta signal and outputting a selected signal as the update signal in response to a predetermined control signal.

9. The channel equalizing system of claim 5, wherein within the header period, the common equalizer updates even tap coefficients including a predetermined center tap coefficient among the FD-QAM tap coefficients and the QAM tap coefficients at a predetermined symbol time and the odd tap coefficients among the QAM tap coefficients without updating the FD-QAM tap coefficients at a predetermined zero time when the center tap coefficient is an even tap coefficient, and updates odd tap coefficients including a predetermined center tap coefficient among the FD-QAM tap coefficients and the QAM tap coefficients at the symbol time and the even tap coefficients among the QAM tap coefficients without updating the FD-QAM tap coefficients at the zero time when the center tap coefficient is an odd tap coefficient.

10. The channel equalizing system of claim 5, wherein within a predetermined payload period, the common equalizer updates the FD-QAM tap coefficients only at a predetermined symbol time when the FD-QAM signal is received and updates the QAM tap coefficients for every symbol when the QAM signal is received.

11. An adaptive channel equalizing method for a home phoneline networking alliance (HomCPNA) receiver, the channel equalizing method comprising:

(a) receiving a frequency diverse quadrature amplitude modulation (FD-QAM) signal during a predetermined header period, determining FD-QAM tap coefficients, and equalizing the FD-QAM signal using the FD-QAM tap coefficients;

(b) receiving the FD-QAM signal during the header period and determining quadrature amplitude modulation (QAM) tap coefficients;

(c) updating, continuously, the FD-QAM tap coefficients to equalize the FD-QAM signal upon receiving the FD-QAM signal during a predetermined payload period; and

(d) updating, continuously, the QAM tap coefficients to equalize the QAM signal upon receiving a QAM signal is received during the payload period.

12. The channel equalizing method of claim 11, wherein in steps (a) and (c), the FD-QAM tap coefficients are updated at a predetermined symbol time and are not updated at a predetermined zero time.

13. The channel equalizing method of claim 11, wherein step (b) comprises updating even tap coefficients including a predetermined center tap coefficient among the QAM tap coefficients at a predetermined symbol time and odd tap coefficients at a predetermined zero time when the center tap coefficient is an even tap coefficient and updating odd tap coefficients including a predetermined center tap coefficient among the QAM tap coefficients at the symbol time and the even tap coefficients at the zero time when the center tap coefficient is an odd tap coefficient.

14. The channel equalizing method of claim 11, wherein step (c) comprises updating all of the QAM tap coefficients for each symbol.

15. An adaptive channel equalizing system for a home phoneline networking alliance (HomePNA) receiver, the channel equalizing system comprising:

a frequency diverse quadrature amplitude modulation (FD-QAM) equalizer for determining FD-QAM tap coefficients and equalizing an FD-QAM signal input into the adaptive channel equalizing system;

a quadrature amplitude modulation (QAM) equalizer for receiving the FD-QAM signal determines QAM tap coefficients during a predetermined header period, and continuously updating the QAM tap coefficients during a predetermined payload period to equalize the QAM signal upon receiving the QAM signal,

wherein within the header period, the QAM equalizer updates even tap coefficients including a predetermined center tap coefficient among the QAM tap coefficients at a predetermined symbol time and the odd tap coefficients at a predetermined zero time when the center tap coefficient is an even tap coefficient, and updates odd tap coefficients including a predetermined center tap coefficient among the QAM tap coefficients at the symbol time and the even tap coefficients at the zero time when the center tap coefficient is an odd tap coefficient, and

during the payload period, the QAM equalizer updates all of the QAM tap coefficients for every symbol.