APPLICATION LAYER FEC FRAMEWORK FOR WiGig

• US 20110219279A1
• Filed: 03/02/2011
• Published: 09/08/2011
• Est. Priority Date: 03/05/2010
• Status: Active Grant

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Khan, Farooq, Abu-Surra, Shadi, Pisek, Eran
• Granted Patent: US 8,839,078 B2
• Time in Patent Office: Days
• US Class Current: 714/746
• CPC Class Codes: H03M 13/098 using single parity bit
• CPC Class Codes: H03M 13/1102 Codes on graphs and decoding on graphs, e.g. low-density parity check [LDPC] codes
• CPC Class Codes: H03M 13/19 Single error correction without using particular properties of the cyclic codes, e.g. Hamming codes, extended or generalised Hamming codes
• CPC Class Codes: H03M 13/23 using convolutional codes, e.g. unit memory codes
• CPC Class Codes: H03M 13/2707 Simple row-column interleaver, i.e. pure block interleaving
• CPC Class Codes: H03M 13/2906 using block codes H03M13/2957 takes precedence
• CPC Class Codes: H03M 13/2966 Turbo codes concatenated with another code, e.g. an outer block code
• CPC Class Codes: H03M 13/373 with erasure correction and erasure determination, e.g. for packet loss recovery or setting of erasures for the decoding of Reed-Solomon codes
• CPC Class Codes: H03M 13/3761 using code combining, i.e. using combining of codeword portions which may have been transmitted separately, e.g. Digital Fountain codes, Raptor codes or Luby Transform [LT] codes
• CPC Class Codes: H04L 1/0041 Arrangements at the transmitter end
• CPC Class Codes: H04L 1/0057 Block codes H04L1/0061, H04L1/0064 take precedence

Abstract

A method and apparatus perform forward error correction in a wireless communication device in a wireless communication network. Application layer forward error correction (AL-FEC) capability information is transmitted during a capabilities exchange. A set of source packets are reshaped to k equal-sized source symbols. Systematic packets for the source symbols and at least one parity packet is encoded using a single parity check (SPC) AL-FEC code on the k source symbols. A header of each encoded packet includes a parity packet indicator. The encoded packets are processed in a media access control (MAC) layer and a physical (PHY) layer for transmission.

Claims

1. A method of performing forward error correction (FEC) in a wireless communication device in a wireless communication network, the method comprising:

transmitting application layer forward error correction (AL-FEC) capability information during a capabilities exchange;

reshaping a set of source packets to k equal-sized source symbols;

encoding systematic packets for the source symbols and at least one parity packet using a single parity check (SPC) AL-FEC code on the k source symbols, a header of each encoded packet comprising a parity packet indicator; and

processing the encoded packets in a media access control (MAC) layer and a physical (PHY) layer for transmission.

2. The method of claim 1, wherein the SPC AL-FEC code comprises one of a non-interleaved mode and an interleaved mode.

3. The method of claim 2, wherein when the SPC AL-FEC code comprises the non-interleaved mode, encoding the systematic packets and the at least one parity packet comprises:

generating a sequence number i for one parity packet;

generating sequence numbers i+1, i+2, . . . , i+k for the k source symbols; and

performing a bit-wise XOR on the k source symbols to compute a payload for the parity packet with the sequence number i,

wherein the sequence number for the parity packet is included in the header for the parity packet, and the sequence numbers for the k source symbols are included in the headers for the corresponding systematic packets.

4. The method of claim 2, wherein when the SPC AL-FEC code comprises the interleaved mode with x subsets of source symbols, encoding the systematic packets and the at least one parity packet comprises:

generating sequence numbers i, i+1, i+2, . . . , i+(x−

1) for x parity packets, each parity packet corresponding to one of x subsets of source symbols;

generating sequence numbers i+1, i+2, . . . , i+k for the k source symbols;

interleaving the k source symbols across the x subsets such that source symbols with consecutive sequence numbers correspond to different subsets; and

computing a payload for each parity packet by performing a bit-wise XOR on the corresponding subset of source symbols,

wherein the sequence numbers for the parity packets are included in the headers for the corresponding parity packets, and the sequence numbers for the k source symbols are included in the headers for the corresponding systematic packets.

5. The method of claim 1, wherein encoding systematic packets for the source symbols and at least one parity packet comprises performing a Hamming AL-FEC code in combination with the SPC AL-FEC code.

6. The method of claim 1, further comprising:

receiving a packet block comprising at least one of systematic packets and repair packets;

determining whether at least one packet is missing in the received packet block;

when at least packet is missing, determining whether the received packets are AL-FEC encoded by checking the parity packet indicator in each received packet;

when the AL-FEC code is detected, determining whether the at least one missing packet may be recovered; and

in response to determining that the at least one missing packets may be recovered, performing AL-FEC decoding by using the received systematic and repair packets.

7. The method of claim 6, wherein determining whether the received packets are AL-FEC encoded further comprises determining whether the received packets are interleaved based on a number of parity packets received.

8. An apparatus for performing forward error correction (FEC) in a wireless communication device in a wireless communication network, the apparatus comprising:

a transmitter configured to communicate with other communication devices; and

a controller coupled to the transmitter and configured to;

transmit application layer forward error correction (AL-FEC) capability information during a capabilities exchange;

reshape a set of source packets to k equal-sized source symbols;

encode systematic packets for the source symbols and at least one parity packet using a single parity check (SPC) AL-FEC code on the k source symbols, a header of each encoded packet comprising a parity packet indicator; and

process the encoded packets in a media access control (MAC) layer and a physical (PHY) layer for transmission.

9. The apparatus of claim 8, wherein the SPC AL-FEC code comprises one of a non-interleaved mode and an interleaved mode.

10. The apparatus of claim 9, wherein when the SPC AL-FEC code comprises the non-interleaved mode, the controller is further configured to:

generate a sequence number i for one parity packet;

generate sequence numbers i+1, i+2, . . . , i+k for the k source symbols; and

perform a bit-wise XOR on the k source symbols to compute a payload for the parity packet with the sequence number i,

wherein the sequence number for the parity packet is included in the header for the parity packet, and the sequence numbers for the k source symbols are included in the headers for the corresponding systematic packets.

11. The apparatus of claim 9, wherein when the SPC AL-FEC code comprises the interleaved mode with x subsets of source symbols, the controller is further configured to:

generate sequence numbers i, i+1, i+2, i+(x−

1) for x parity packets, each parity packet corresponding to one of x subsets of source symbols;

generate sequence numbers i+1, i+2, . . . , i+k for the k source symbols;

interleave the k source symbols across the x subsets such that source symbols with consecutive sequence numbers correspond to different subsets; and

compute a payload for each parity packet by performing a bit-wise XOR on the corresponding subset of source symbols,

wherein the sequence numbers for the parity packets are included in the headers for the corresponding parity packets, and the sequence numbers for the k source symbols are included in the headers for the corresponding systematic packets.

12. The apparatus of claim 8, wherein the controller is further configured to perform a Hamming AL-FEC code in combination with the SPC AL-FEC code when encoding the systematic packets for the source symbols and at least one parity packet by.

13. The apparatus of claim 8, wherein the controller is further configured to:

receive at least one of systematic packets and repair packets;

determine whether at least one packet is missing;

when any packet is missing, determine whether the received packets are AL-FEC encoded by checking the parity packet indicator in each received packet to;

when the AL-FEC code is detected, determine whether the missing packets may be recovered; and

in response to determining that the missing packets may be recovered, perform AL-FEC decoding by using the received systematic and repair packets.

14. The apparatus of claim 13, wherein the controller is further configured to determine whether the received packets are interleaved based on a number of parity packets received when determining whether the received packets are AL-FEC encoded.

15. A method of performing forward error correction (FEC) in a wireless communication device in a wireless communication network, the method comprising:

transmitting application layer forward error correction (AL-FEC) capability information during a capabilities exchange;

reshaping a set of source packets to form a set of equal-sized source symbols;

encoding systematic packets and at least one repair packet using an AL-FEC code on the source symbols, a header of each encoded packet comprising a parity packet indicator; and

processing the encoded packets in a media access control (MAC) layer and a physical (PHY) layer for transmission.

16. The method of claim 15, wherein the AL-FEC code comprises one of a single parity check (SPC) , a convolutional code, and a Hamming code.

17. The method of claim 15, wherein the SPC AL-FEC code interleaves the source symbols.

18. The method of claim 15, wherein the AL-FEC code comprises a Hamming code with a single parity check.

19. The method of claim 15, further comprising:

receiving a packet block comprising at least one of systematic packets and repair packets;

determining whether at least one packet is missing in the received packet block;

when at least one packet is missing, determining whether the received packets are AL-FEC encoded by checking the parity packet indicator in each received packet;

when the AL-FEC code is detected, determining whether the at least one missing packet may be recovered; and

in response to determining that the at least one missing packet may be recovered, performing AL-FEC decoding by using the received systematic and repair packets.

20. The method of claim 19, wherein determining whether the received packets are AL-FEC encoded further comprises determining whether the received packets are interleaved based on a number of parity packets received.