Dynamic frame structure for synchronous time-division duplexing digital subscriber lines

An access node for digital subscriber line (DSL) communication comprising:

• a transceiver configured to couple a subscriber line;
• and
• a control entity coupled to the transceiver, wherein the control entity is configured to:
• receive a request to switch to a nominal asymmetry ratio between an upstream data rate and a downstream data rate after initialization of the subscriber line;
• determine a flexible time period value based on the nominal asymmetry ratio, wherein the flexible time period is used to define a time division duplexing (TDD) frame structure;
• and
• forward a message that comprises the flexible time period value to the transceiver, wherein the transceiver is configured to:
• transmit a downstream transmission using the TDD frame structure over the subscriber line;
• and
• receive an upstream transmission using the TDD frame structure over the subscriber line,
• wherein the subscriber line comprises a wired connection, wherein the TDD frame structure comprises a fixed downstream time period and a fixed upstream time period, wherein the fixed downstream time period indicates a minimum time period allocated for the downstream transmission, wherein the fixed upstream time period indicates a minimum time period allocated for the upstream transmission, and wherein the TDD frame structure comprises a flexible time period, and wherein a length of the flexible time period is set by the flexible time period value.

An access node for digital subscriber line (DSL) communication over a plurality of subscriber lines comprising:

• a control entity;
• a transceiver coupled to the control entity, wherein the transceiver is configured to:
• determine a number of active symbols to be transmitted within a time division duplexing (TDD) frame;
• and
• transmit a downstream transmission portion of the TDD frame via a first subscriber line using the number of active symbols to be transmitted,
• wherein the TDD frame comprises a plurality of symbols,
• wherein the number of active symbols to be transmitted is no more than a total number of symbols allocated for the downstream transmission portion of the TDD frame,
• wherein a downstream transmitter of the first subscriber line is powered off after the transmission of the active symbols during the downstream transmission portion of the TDD frame, and
• wherein the plurality of subscriber lines comprise wired connections, wherein the control entity is configured forward information to a second subscriber line that the downstream transmitter of the first subscriber line will power off after the transmission of the active symbols during the downstream transmission portion of the TDD frame, wherein the control entity is further configured to receive information from the second subscriber line that a transmitter of the second subscriber line will power off, and wherein the transceiver does not increase the number of active symbols transmitted during the downstream portion of the TDD frame when the transmitter of the second subscriber line powers off.

A method for digital subscriber line (DSL) communication at an access node, comprising:

• coupling, with a transceiver, a subscriber line;
• receiving, by a control entity coupled to the transceiver, a request to switch to a nominal asymmetry ratio between an upstream data rate and a downstream data rate after initialization of the subscriber line;
• determining, by the control entity, a flexible time period value based on the nominal asymmetry ratio, wherein the flexible time period is used to define a time division duplexing (TDD) frame structure;
• forwarding, by the control entity, a message comprising the flexible time period value to the transceiver;
• transmitting, by the transceiver, a downstream transmission using the TDD frame structure over the subscriber line;
• and
• receiving, by the transceiver, an upstream transmission using the TDD frame structure over the subscriber line, wherein the subscriber line comprises a wired connection, wherein the TDD frame structure comprises a fixed downstream time period and a fixed upstream time period, wherein the fixed downstream time period indicates a minimum time period allocated for the downstream transmission, wherein the fixed upstream time period indicates a minimum time period allocated for the upstream transmission, and wherein the TDD frame structure comprises a flexible time period, and wherein a length of the flexible time period is set by the flexible time period value.