Method and system for initiating bi-directional communication in a time-division duplex communication system

摘要

The present invention relates to a method and a system for initiating bi-directional communication in a time-division duplex (TDD) communication system between a customer premises equipment (CPE) modem, such as a DSL modem, and an operator modem, such as a DSLAM. The invention is characterized in that the transmission of the CPE modem is aligned with the time-division duplex timing structure present in received crosstalk noise when transmitting initiation signals, so-called handshake tones.

主权项

1. A method at a customer premises equipment (CPE) modem for initiating bi-directional communication in a time-division duplex (TDD) communication system between the CPE modem and an operator modem, the method comprising:
receiving by the CPE modem noise induced by crosstalk for consecutive discrete time slots in a transmission frequency band, identifying at the CPE modem a timing structure of time slots in the transmission frequency band using the noise induced by crosstalk for the consecutive discrete time slots, interpreting at the CPE modem a direction of transmission in the time slots based on the timing structure identified using the noise induced by crosstalk, aligning transmission of the CPE modem with the time-division duplex timing structure present in the received noise induced by crosstalk, by transmitting initiation signals from the CPE modem to the operator modem in time periods between downstream transmission slots, receiving by the CPE modem an initiation response signal transmitted from the operator modem in downstream transmission time slots, and after transmitting the initiation signals and after receiving the initiation response, proceeding at the CPE modem with a subsequent initiation procedure to establish bi-directional communication between the CPE modem and the operator modem; wherein the initiation signals comprise handshake tones, and wherein the initiation response signal comprises a handshake response signal.