Mapping of bit streams into MPEG frames
View Patent ↗An architecture for providing high-speed access over frequency-division multiplexed (FDM) channels allows transmission of ethernet frames and/or other data across a cable transmission network or other form of FDM transport. The architecture involves downstream and upstream FDM multiplexing techniques to allow contemporaneous, parallel communications across a plurality of frequency channels. Each downstream data flow is fragmented into individual octets that are multiplexed into MPEG packets. An MPEG packet may carry the octets for a plurality of individual data flows. Furthermore, the MPEG packets may be frequency-division multiplexed across and may be contemporaneously communicated over a plurality of frequency channels. Also, the octets from a data flow do not necessarily have to use consecutive octets in an MPEG packet. Instead, consecutive octets in an MPEG packet may carry information for two different data flows. Thus, in an MPEG packet there may be intervening octets that might be allocated to other data flows between the octets of an ethernet frame or other type of data from one data flow. In addition, the data flows carried in MPEG packets may support one or a plurality of client devices. Therefore, an MPEG packet may be used to time-division multiplex multiple data flows to one or a plurality of client devices.
1. A method of communicating a plurality of flows of frames carried in a packet, the method comprising:
placing a first octet from a first one of the flows in the packet;
placing a second octet from a second one of the flows into the packet; and
transmitting the packet on a frequency channel;
wherein the first flow of frames contains data that is segregated from the second flow of frames, and wherein one first client device forwards information from the first flow of frames and forwards information from the second flow of frames.
2. The method of claim 1 , wherein the packet is an MPEG packet.
3. A method of communicating a plurality of flows of frames carried in a packet, the method comprising:
placing a first octet from a first one of the flows in the packet;
placing a second octet from a second one of the flows into the packet; and
transmitting the packet on a frequency channel;
wherein the first flow of frames contains data that is segregated from the second flow of frames, and wherein one first client device forwards information from the first flow of frames and discards information from the second flow of frames that is destined for at least one second client device.
4. The method of claim 3 , wherein the packet is an MPEG packet.
5. A method of communicating a plurality of frames, each frame including a plurality of octet positions, using a series of packets, each packet including a plurality of octet positions, the method comprising the steps of:
reading data from one octet position in a first of the frames and placing the data to a specified octet position in a first of the packets in accordance with an allocation map that specifies the octet position in the first packet;
reading data from another octet position in the first frame and placing the data to a specified octet position in a second of the packets in accordance with the allocation map that specifies the octet position in the second packet;
transmitting the first packet on a first frequency channel; and
transmitting the second packet on a second frequency channel different than the first frequency channel.
6. The method of claim 5 , wherein the reading of data from one octet position in the first of the frames uses a counter which indexes into the allocation map.
7. The method of claim 5 , wherein the reading of data from data at one octet position in the first of the frames further comprises using a counter to determine which packet of the series of packets is the first packet in the series of packets.
8. The method of claim 5 , further comprising the steps of:
selecting, based on the allocation map, the first packet and the octet position in the first packet;
determining whether the octet position in the first packet and in the second packet are the same; and
responsive to the determination that the octet positions are the same, selecting the second packet to follow the first packet in the series of packets.
9. The method of claim 5 , wherein the reading of data from one octet position in the first frame step further comprises:
selecting the first packet from the series of packets according to a packet write-in direction whenever the allocation map specifies the same octet number as a last selected packet.
10. The method of claim 5 , further comprising the steps of:
selecting the first frame from a first data flow;
selecting a second frame from a second data flow different than the first data flow; and
placing data from an octet position in the second frame to an octet position in one of the packets different than the first packet.
11. The method of claim 10 , wherein the first data flow comprises a frame management sublayer data flow.
12. The method of claim 5 , wherein the another octet position in the first frame succeeds the one octet position in the first frame, and the reading of data from the another octet position is performed after the step of placing copying data at the one octet position.
13. The method of claim 5 , wherein the one octet position in the one of the frames and the another octet position in the one of the frames are consecutive.
14. The method of claim 5 , wherein the transmitting steps are performed contemporaneously.
15. The method of claim 5 , wherein the frames comprise Ethernet/802.3 frames and the packets comprise MPEG-2 packets.