Time to time-frequency mapping and demapping for ethernet passive optical network over coax (EPoC)
View Patent ↗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 (FCU). Embodiments further include systems and methods for re-generating a data burst from OFDMA resources for transmission from the FCU to an Optical Line Terminal (OLT).
1. An Ethernet Passive Optical Network over Coax (EPoC) physical layer (PHY) chip for use in a Coaxial Network Unit (CNU), comprising:
a PHY controller configured to receive a Medium Access Control (MAC) bit stream, determine a transmission time duration for the MAC bit stream, and translate the transmission time duration into a frame number and a subcarrier group, wherein the frame number identifies an upstream scheduled multi-subcarrier frame and the subcarrier group identifies a plurality of subcarriers of the multi-subcarrier frame.
2. The EPoC PHY chip of claim 1 , wherein the PHY controller is configured to receive the MAC bit stream from a MAC layer via a MAC-PHY interface.
3. The EPoC PHY chip of claim 2 , wherein the PHY controller is configured to determine the transmission time duration for the MAC bit stream based on a bit size of the MAC bit stream and an upstream bit loading profile.
4. The EPoC PHY chip of claim 3 , wherein the PHY controller is configured to determine the bit size of the MAC bit stream based on a start transmission time and an end transmission time of the MAC bit stream over the MAC-PHY interface.
5. The EPoC PITY chip of claim 4 , wherein the PHY controller is configured to translate the transmission time duration into the frame number and the subcarrier group based on the start transmission time of the MAC bit stream over the MAC-PHY interface.
6. The EPoC PHY chip of claim 1 , wherein the multi-subcarrier frame includes an Orthogonal Frequency Division Multiple Access (OFDMA) frame comprising a plurality of time consecutive OFDMA symbols.
7. The EPoC PHY chip of claim 1 , wherein the PHY controller is further configured to map the MAC bit stream to the subcarrier group based on an upstream bit loading profile.
8. The EPoC PHY chip of claim 7 , 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 the upstream bit loading profile, wherein the symbol bit loading indicates a number of bits that can be carried by the subcarrier in one symbol time;
determine, using the symbol bit loading, a total number of bits that can be carried by the subcarrier across the multiple time consecutive symbols of the multi-subcarrier frame; and
map bits from the MAC bit stream to the subcarrier in accordance with the total number of bits.
9. The EPOC PHY chip of claim 1 , wherein the PHY controller is further configured to:
transmit a signal on an upstream control channel according to a local frame start time;
receive a time offset on a downstream control channel; and
adjust the local frame start time using the time offset.
10. A method, comprising:
receiving a Medium Access Control (MAC) bit stream;
determining a transmission time duration for the MAC bit stream; and
translating the transmission time duration into a frame number and a subcarrier group, wherein the frame number identifies an upstream scheduled multi-subcarrier frame and the subcarrier group identifies a plurality of subcarriers of the multi-subcarrier frame.
11. The method of claim 10 , wherein determining the transmission time duration for the MAC bit stream comprises determining the transmission time duration for the MAC bit stream based on a bit size of the MAC bit stream and an upstream bit loading profile.
12. The method of claim 10 , wherein the multi-subcarrier frame includes an Orthogonal Frequency Division Multiple Access (OFDMA) frame comprising a plurality of time consecutive OFDMA symbols.
13. The method of claim 10 , wherein the multi-subcarrier frame comprises multiple time consecutive symbols, and wherein the method further comprises:
determining a symbol bit loading for a subcarrier of the subcarrier group, wherein the symbol bit loading indicates a number of bits that can be carried by the subcarrier in one symbol time;
determining, using the symbol bit loading, a total number of bits that can be carried by the subcarrier across the multiple time consecutive symbols of the multi-subcarrier frame; and
mapping bits from the MAC bit stream to the subcarrier in accordance with the total number of bits.
14. The method of claim 10 , further comprising:
transmitting a signal on an upstream control channel according to a local frame start time;
receiving a time offset on a downstream control channel; and
adjusting the local frame start time using the time offset.
15. An Ethernet Passive Optical Network over Coax (EPoC) physical layer (PHY) chip for use in a Coaxial Network Unit (CNU), comprising:
a Medium Access Control (MAC) layer configured to output a MAC bit stream over a MAC-PHY interface; and
a PHY controller configured to receive the MAC bit stream via the MAC-PHY interface, determine a transmission time duration for the MAC bit stream, and, based on a start transmission time of the MAC bit stream over the MAC-PHY interface, translate the transmission time duration into a frame number and a subcarrier group.
16. The EPoC PHY chip of claim 15 , wherein the MAC layer is synchronized with a serving optical line terminal (OLT) MAC layer.
17. The EPoC PHY chip of claim 15 , wherein the frame number identifies an upstream scheduled multi-subcarrier frame and the subcarrier group identifies a plurality of subcarriers of the upstream scheduled multi-subcarrier frame.
18. The EPoC PHY chip of claim 15 , wherein the PHY controller is configured to determine the transmission time duration for the MAC bit stream based on a bit size of the MAC bit stream and an upstream bit loading profile.
19. The EPoC PHY chip of claim 17 , wherein the upstream scheduled multi-subcarrier frame includes an Orthogonal Frequency Division Multiple Access (OFDMA) frame comprising a plurality of time consecutive OFDMA symbols.
20. The EPoC PHY chip of claim 15 , wherein the PHY controller is further configured to map the MAC bit stream to the subcarrier group based on an upstream bit loading profile.