MAC structure with packet-quasi-static blocks and ARQ
View Patent ↗A MAC layer protocol that converts packets into a data stream is presented. The protocol layer accepts packets (like Ethernet packets) and converts them into blocks. The packets may be segmented into multiple hocks and multiple packets or packet fragments may be contained in a block. The blocks contain information for reassembling the data. All blocks may be exactly the same size and format, with the same coding. This allows blocks to be precisely recovered even when some of the bits on the stream have errors on them. The blocks may be interleaved and coded. Each block may be decoded independently of other blocks. The blocks may be numbered, so an ARQ mechanism may request that any missing blocks be resent without asking for a whole packet to be resent. The data stream may be passed to a physical layer like an OFDM or WOFDM stream of data.
1. A method, implementable on a transmitter, for preparing data blocks for physical transmission over a physical channel on a noisy shared medium, the method comprising:
segmenting a sequence of concatenated, variable length data packets into one or more of said data blocks of a fixed size currently defined for said physical channel, wherein at least one of the data blocks contains more than one packet;
adding an indication to a data block of a start location within said block of a next packet at least to indicate to a receiver of said block where a next packet starts;
providing said data blocks at least for encoding and said physical transmission onto said noisy shared medium; and
managing said data blocks for possible retransmission.
2. The method according to claim 1 and wherein said segmenting comprises padding said sequence.
3. The method according to claim 1 , wherein said packets are formatted packets.
4. The method according to claim 1 , wherein said providing comprises adding CRC error detection coding to said data blocks.
5. The method of claim 4 , and also comprising Reed-Solomon encoding of each of said data blocks.
6. The method of claim 1 , wherein said packets comprise at least one of: application data and control messages.
7. The method of claim 6 , wherein said segmenting comprises:
segmenting said control messages;
segmenting said application data;
placing said segmented control messages into one or more of said data blocks; and
placing said segmented application data into a remainder of said data blocks.
8. The method of claim 6 , wherein said segmenting comprises:
segmenting said control messages;
segmenting said application data;
placing said segmented control messages into one or more of said data blocks; and
placing said segmented application data into one or more other data blocks.
9. The method of claim 1 , and wherein said managing comprises numbering each said data block for Automatic Repeat Request (ARQ) management and packet re-assembly.
10. The method according to claim 1 and wherein said noisy shared medium is a powerline.
11. A method implementable on a receiver, for receiving data blocks from a noisy shared medium, the method comprising:
receiving a sequence of said data blocks from said noisy shared medium, said data blocks being of a fixed size currently defined for a physical channel, wherein at least one of the data blocks contains more than one packet;
reading formatting of each of said data blocks to determine, if present, a start location of a new packet;
adding data before said start location to a previous packet currently in reassembly;
reassembling a new packet from said start location irrespective of the assembly status of the previous packet; and
if a data block was received with an error, waiting for its retransmission to finish assembly of the packet to which it belongs.
12. The method of claim 11 , and also comprising decoding each of said data blocks with its error correction and/or error detection code.
13. The method of claim 11 , wherein said decoding comprises Cyclic Redundancy Checksum decoding.