# US 2013/0159808 A1 · System for Communicating Data in xDSL Using Data Retransmission > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2013/0159808 A1 - Document ID: US20130159808A1 - Status: Published application - Kind: A1 - Application number: 13/766,887 - Filed: 2013-02-14 - Published: 2013-06-20 - Earliest claimed: 2006-09-13 - Assignees: Broadcom Corporation - Inventors: Benoit CHRISTIAENS; Miguel PEETERS; Raphael CASSIERS - Web page: https://patentgrep.com/patent/US20130159808A1 ## CPC - H04L 1/1867: Arrangements specially adapted for the transmitter end - H04L 1/0041: {Arrangements at the transmitter end} - H04L 1/0057: {Block codes (H04L1/0061, H04L1/0064 take precedence)} - H04L 1/0071: {Use of interleaving (interleaving per se H03M13/27)} - H04L 1/08: by repeating transmission, e.g. Verdan system {(H04L1/1858 and H04L1/189 take precedence)} - H04L 1/1614: {using bitmaps} - H04L 1/1642: {Formats specially adapted for sequence numbers} - H04L 1/1812: Hybrid protocols; Hybrid automatic repeat request [HARQ] - H04L 1/1874: {Buffer management} - H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M) ## Abstract Embodiments described herein provide an apparatus for transmitting data in an xDSL. In one example, the apparatus can include a transmitter configured to transmit data over the xDSL system in the form of data transmission units (DTUs), the transmitter having a physical media specific-transmission convergence (PMS-TC) communication sublayer and a retransmission unit that is implemented in the PMS-TC sublayer, the retransmission unit including a retransmission buffer configured to store transmitted DTUs and to index the transmitted DTUs using retransmit containers, each retransmit container being defined as a time slot corresponding to a respective sent DTU. A retransmit request specifies a DTU by a corresponding retransmit container and wherein the retransmission unit is configured to retransmit the specified DTU in response to the retransmit request. ## Claims ### Claim 1 An apparatus thr transmitting data in an xDSL system, comprising: a transmitter configured to transmit data over the xDSL system in the form of data transmission units (DTUs), the transmitter having a physical media specific-transmission convergence (PMS-TC) communication sublayer; and a retransmission unit that is implemented in the PMS-TC sublayer, the retransmission unit including a retransmission buffer configured to store transmitted DTUs and to index the transmitted DTUs using retransmit containers, each retransmit container being defined as a time slot corresponding to a respective sent DTU; wherein a retransmit request specifies a DTU by a corresponding retransmit container and wherein the retransmission unit is configured to retransmit the specified DTU in response to the retransmit request. ### Claim 2 (depends on 1) The apparatus of claim 1, wherein the retransmission unit is configured to further identify the specified DTU by a unique sequence identification number (SID) that is added to the specified DTU in the PMS-TC sublayer. ### Claim 3 (depends on 1) The apparatus of claim 1, further comprising: a forward error correction unit coupled to the retransmission buffer and configured to encode DTUs to be transmitted by the transmitter. ### Claim 4 (depends on 3) The apparatus of claim 3, wherein the forward error correction unit is configured to use Reed-Solomon encoding to encode the DTUs to be transmitted by the transmitter. ### Claim 5 (depends on 3) The apparatus of claim 3, wherein each of the DTUs to be transmitted by the transmitter is defined as a group of n consecutive code words. ### Claim 6 (depends on 1) The apparatus of claim 1, further comprising: a retransmission control channel implemented in the PMS-TC sublayer, wherein the retransmission control channel is configured to receive the retransmission request from a receiver and retransmit the specified DTU. ### Claim 7 (depends on 1) The apparatus of claim 1, wherein the retransmission buffer is configured to store the requested DTU for a period of time sufficient to determine whether the requested DTU was corrupted. ### Claim 8 (depends on 1) The apparatus of claim 1, wherein each of the DTUs to be transmitted by the transmitter is defined as one of a group of D Reed Solomon code words, a block of asynchronous transfer mode (ATM) cells, or a packet transfer mode (PTM) code word. ### Claim 9 (depends on 1) The apparatus of claim 1, wherein the retransmission unit is configured to determine that an acknowledgement for a DTU stored in retransmission buffer has not been received and to identify the stored DTU by its corresponding retransmit container for retransmission. ### Claim 10 (depends on 1) The apparatus of claim 1, wherein the transmitter is configured to transmit the data over the xDSL system to a receiver and wherein the receiver is configured to store retransmit containers corresponding to received DTUs independently of the transmitter. ### Claim 11 An apparatus for transmitting data in an xDSL system, comprising: a transmitter configured to transmit data over the xDSL system in the form of data transmission units (DTUs), the transmitter having a physical media specific-transmission convergence (PMS-TC) communication sublayer and a physical media dependent (PMD) communication sublayer; a retransmission sublayer implemented between the PMS-TC and PMD communication sublayers; and a retransmission unit implemented in the retransmission sublayer, the retransmission unit including a retransmission buffer configured to store transmitted DTUs and to index transmitted DTUs using retransmit containers, each retransmit container being defined as a time slot corresponding to a respective sent DTU; wherein a retransmit request specifies a DTU by a corresponding retransmit container and wherein the retransmission unit is configured to retransmit the specified DTU in response to the retransmit request. ### Claim 12 (depends on 11) The apparatus of claim 11, wherein the specified DTU is further identified by a unique sequence identification number (SID) that is added to the DTU in the retransmission sublayer. ### Claim 13 (depends on 11) The apparatus of claim 11, wherein each DTU is defined as a group of L bits mapped in a single DMT symbol. ### Claim 14 (depends on 11) The apparatus of claim 11, wherein the retransmission buffer is configured to store the specified DTU for a period of time sufficient to determine whether the requested DTU was corrupted. ### Claim 15 (depends on 11) The apparatus of claim 11, wherein the specified DTU is defined as one of a group of D Reed Solomon code words, a block of asynchronous transfer mode (ATM) cells, or a packet transfer mode (PTM) code word. ### Claim 16 (depends on 11) The apparatus of claim 11, wherein the retransmission unit is configured to determine that an acknowledgement for a DTU stored in the retransmission buffer has not been received and to identify the stored DTU by its corresponding retransmit container for retransmission. ### Claim 17 (depends on 11) The apparatus of claim 11, further comprising: a forward error correction unit coupled to the retransmission buffer and configured to encode DTUs to be transmitted by the transmitter. ### Claim 18 (depends on 11) The apparatus of claim 11, wherein each of the DTUs to be transmitted by the transmitter is defined as one of a group of D Reed Solomon code words, a block of asynchronous transfer mode (ATM) cells, or a packet transfer mode (PTM) code word. ### Claim 19 (depends on 11) The apparatus of claim 11, wherein the retransmission unit is configured to determine that an acknowledgement for a DTU stored in retransmission buffer has not been received and to identify the stored DTU by its corresponding retransmit container for retransmission. ### Claim 20 (depends on 11) The apparatus of claim 11, wherein the transmitter is configured to transmit the data over the xDSL system to a receiver and wherein the receiver is configured to store retransmit containers corresponding to received DTUs independently of the transmitter.