Time to Time-Frequency Mapping and Demapping for Ethernet Passive Optical Network over Coax (EPoC)

Abstract

Embodiments include, but are not limited to, systems and methods for enabling Orthogonal Frequency Division Multiple Access (OFDMA) in the upstream in an Ethernet Passive Optical Network over Coax (EPoC) network. Embodiments include systems and methods for translating Ethernet Passive Optical Network (EPON) upstream time grants to OFDMA resources represented by individual subcarriers of an upstream OFDMA frame. In an embodiment, the translation of EPON upstream time grants to OFDMA resources ensures that Coaxial Network Units (CNUs) sharing an OFDMA frame do not use overlapping subcarriers within the frame. Embodiments further include systems and methods for timing upstream transmissions by the CNUs in order for the transmissions to be received within the same upstream OFDMA frame at a Fiber Coax Unit (ECU). Embodiments further include systems and methods for regenerating a data burst from OFDMA resources for transmission from the ECU to an Optical Line Terminal (OLT).

What is claimed is: 
     
         1 . An Ethernet Passive Optical Network over Coax (EPoC) physical layer (PHY) chip for use in a Fiber Coax Unit (FCU), comprising:
 a PHY controller configured to receive a multi-subcarrier frame containing first and second transmissions from a first Coaxial Network Unit (CNU) and a second CNU; identify a first subcarrier group of the multi-subcarrier frame carrying the first transmission from the first CNU; and generate a bit stream using the first subcarrier group.   
     
     
         2 . The EPoC PHY chip of  claim 1 , wherein the PHY controller is configured to identify the first subcarrier group using a start marker and an end marker inserted in the first subcarrier group by the first CNU. 
     
     
         3 . The EPoC PHY chip of  claim 2 , further comprising:
 a coaxial media converter (CMC) configured to adapt the bit stream for optical transmission to generate an adapted bit stream; and   an optical transceiver configured to generate an optical signal using the adapted bit stream and to transmit the optical signal to an Optical Line Terminal (OLT).   
     
     
         4 . The EPoC PHY chip of  claim 1 , where the multi-subcarrier frame comprises multiple time consecutive symbols, and wherein the PHY controller is further configured to:
 determine a symbol bit loading for a subcarrier of the subcarrier group from an upstream bit loading profile of the first CNU, wherein the symbol bit loading indicates a number of bits that can be carried by the subcarrier in one symbol time from the first CNU; and   demodulate the subcarrier, using the symbol bit loading, over the multiple time consecutive symbols to generate a bit sequence for the subcarrier.   
     
     
         5 . The EPoC PHY chip of  claim 4 , wherein the PHY controller is further configured to append bit sequences generated by demodulating subcarriers of the first subcarrier group to generate the bit stream. 
     
     
         6 . The EPoC PHY chip of  claim 1 , wherein the PHY controller is further configured to determine first and second upstream bit loading profiles for the first and second CNUs respectively and to adjust a subcarrier loading order used by the first CNU based on a comparison of the first and second upstream bit loading profiles. 
     
     
         7 . A method, comprising:
 receiving a multi-subcarrier frame containing first and second transmissions respectively from a first Coaxial'Network Unit (CNU) and a second CNU;   identifying a first subcarrier group of the multi-subcarrier frame using a start marker and an end marker inserted in the first subcarrier group by the first CNU; and   generating a bit stream using the first subcarrier group.   
     
     
         8 . The method of  claim 7 , further comprising:
 adapting the bit stream for optical transmission to generate an adapted bit stream.   
     
     
         9 . The method of  claim 8 , further comprising:
 generating an optical signal using the adapted bit stream; and   transmitting the optical signal to an Optical Line Terminal (OLT).   
     
     
         10 . The method of  claim 7 , wherein the multi-subcarrier frame comprises multiple time consecutive symbols. 
     
     
         11 . The method of  claim 10 , further comprising:
 determining a symbol bit loading for a subcarrier of the subcarrier group from an upstream bit loading profile of the first CNU, wherein the symbol bit loading indicates a number of bits that can be carried by the subcarrier in one symbol time from the first CNU; and   demodulating the subcarrier, using the symbol hit loading, over the multiple time consecutive symbols to generate a bit sequence for the subcarrier.   
     
     
         12 . The method of  claim 11 , further comprising:
 appending hit sequences generated by demodulating subcarriers of the first subcarrier group to generate the bit stream.   
     
     
         13 . The method of  claim 7 , further comprising:
 determining first and second upstream bit loading profiles for the first and second CNUs, respectively.   
     
     
         14 . The method of  claim 13 , further comprising:
 adjusting a subcarrier loading order used by the first CNU based on a comparison of the first and second upstream bit loading profiles.   
     
     
         15 . An Ethernet Passive Optical Network over Coax (EPoC) physical layer (PHY) chip. comprising:
 a PHY controller configured to receive a multi-subcarrier frame containing a transmission from a Coaxial Network Unit (CNU); identify a subcarrier group of the multi-subcarrier frame carrying the transmission from the CNU using a start marker and an end marker inserted in the subcarrier group by the CNU; and generate a bit stream using the subcarrier group.   
     
     
         16 . The EPoC PHY chip of  claim 15 , further comprising:
 a coaxial media converter (CMC) configured to adapt the bit stream for optical transmission to generate an adapted bit stream; and   an optical transceiver configured to generate an optical signal using the adapted bit stream and to transmit the optical signal to an Optical Line Terminal (OLT).   
     
     
         17 . The EPoC PHY chip of  claim 15 , wherein the multi-subcarrier frame comprises multiple time consecutive symbols, and wherein the PHY controller is further configured to:
 determine a symbol bit loading for a subcarrier of the subcarrier group from an upstream bit loading profile of the CNU, wherein the symbol bit loading indicates a number of bits that can be carried by the subcarrier in one symbol time from the CNU; and   demodulate the subcarrier, using the symbol bit loading, over the multiple time consecutive symbols to generate a bit sequence for the subcarrier.   
     
     
         18 . The EPoC PHY chip of  claim 17 , wherein the PHY controller is further configured to append bit sequences generated by demodulating subcarriers of the subcarrier group to generate the bit stream. 
     
     
         19 . The EPoC PHY chip of  claim 15 , wherein the PHY controller is further configured to determine first and second upstream bit loading profiles for the CNU and to adjust a subcarrier loading order used by the CNU based on a comparison of the upstream bit loading profiled to an upstream bit loading profile of another CNU. 
     
     
         20 . The EPoC PHY chip of  claim 15 , wherein the EPoC PHY chip is implemented in a Fiber Coax Unit (FCU).