Error detection in a signal field of a WLAN frame header

• US 9,819,771 B1
• Filed: 07/18/2016
• Issued: 11/14/2017
• Est. Priority Date: 04/12/2010
• Status: Active Grant

• Current Assignee: NXP USA, Inc. (NXP Semiconductors NV)
• Original Assignee: Marvell International Limited (Marvell Technology Group Limited)
• Inventors: Zhang, Hongyuan, Srinivasa, Sudhir
• Primary Examiner(s): Sefcheck, Gregory
• Application Number:
  US15/212,587
• Time in Patent Office: 484 Days
• Field of Search: None
• CPC Class Codes: H04L 1/0041 Arrangements at the transmitter end
• CPC Class Codes: H04L 1/0061 Error detection codes
• CPC Class Codes: H04L 1/0072 Error control for data other than payload data, e.g. control data
• CPC Class Codes: H04L 43/0823 Errors, e.g. transmission errors
• CPC Class Codes: H04L 69/22 Parsing or analysis of headers
• CPC Class Codes: H04W 28/06 Optimizing the usage of the radio link, e.g. header compression, information sizing , discarding information system modifying transmission characteristic according to link quality by modifying frame length H04L1/0007; dynamic adaptation of the packet size for flow control or congestion control H04L47/365
• CPC Class Codes: H04W 84/12 WLAN [Wireless Local Area Networks]

Abstract

In a method for generating data units for transmission via a wireless network, a first signal field that includes formatting information for a data unit is generated, and a CRC field for the first signal field is generated according to a generator polynomial. Further, a second signal field that includes formatting information for the data unit is generated, and a CRC field for the second signal field is generated according to the generator polynomial. Further, the data unit is generated to include i) the CRC for the second signal field and ii) a preamble having a) the first signal field, b) the CRC for the first signal field, and c) the second signal field.

Claims

1. A method for generating data units for transmission in a wireless network, the method comprising:

generating, at a network interface of a wireless network device, the network interface implemented on one or more integrated circuits, a cyclic redundancy check (CRC) sequence based on information bits to be included in a signal field of a data unit, wherein the data unit is to be generated to conform to a first communication protocol, and wherein generating the CRC sequence includes generating the CRC sequence using a CRC polynomial defined by a second communication protocol different from the first communication protocol;

generating, at the network interface of the wireless network device, a CRC field to be included in the data unit, including generating the CRC field to include a portion of the CRC sequence;

generating, at the network interface of the wireless network device, the data unit to conform to the first communication protocol, including generating the data unit to include (i) the signal field and (ii) the CRC field that includes the portion of the CRC sequence such that the data unit does not include the entire CRC sequence; and

causing, with the network interface of the wireless network device, the data unit to be transmitted in the wireless network.

2. The method of claim 1, further comprising truncating, at the network interface of the wireless network device, the CRC sequence to generate the portion of the CRC sequence.

3. The method of claim 1, wherein generating the CRC sequence comprises generating an 8-bit CRC sequence, and wherein generating the CRC field comprises generating the CRC field to include only four bits of the 8-bit CRC sequence.

4. The method of claim 3, wherein generating the CRC field comprises generating the CRC field to include a last four bits of the 8-bit CRC sequence.

5. The method of claim 1, wherein the first communication protocol defines a first number of signal field CRC bits that is less than a second number of signal field CRC bits defined by the second communication protocol, and wherein generating the data unit includes generating the data unit to use one or more bits that are defined as signal field CRC bits by the second communication protocol, but not by the first communication protocol, to include signal field data other than CRC data.

6. The method of claim 1, wherein (i) the data unit is a first data unit, (ii) the signal field is a first signal field, (iii) the CRC sequence is a first CRC sequence, and (iv) the CRC field is a first CRC field, and wherein the method further comprises:

generating, at the network interface of the wireless network device using the generator polynomial, a second cyclic redundancy check (CRC) bit sequence based on information bits to be included in a second signal field, wherein the second signal field is to be included in a second data unit;

generating, at the network interface of the wireless network device, a second CRC field to be included in the second data unit, including generating the second CRC field to include the entire second CRC sequence;

generating, at the network interface of the wireless network device, the second data unit to include (i) the second signal field and (ii) the second CRC field, wherein the second data unit conforms to the second communication protocol.

7. The method of claim 1, wherein generating the data unit to include the signal field comprises generating the data unit to include the signal field in a preamble of the data unit.

8. An apparatus, comprising:

a wireless network interface having one or more integrated circuits, the wireless network interface including;

a medium access control (MAC) processing unit implemented on the one or more integrated circuits, and

a physical layer (PHY) processing unit coupled to the MAC processing unit, the PHY processing unit implemented on the one or more integrated circuits;

wherein the PHY processing unit is configured to

generate a cyclic redundancy check (CRC) sequence based on information bits to be included in a signal field of a data unit, wherein the data unit is to be generated to conform to a first communication protocol, and wherein the PHY processing unit is configured to generate the CRC sequence using a CRC polynomial defined by a second communication protocol different from the first communication protocol;

generate a CRC field to be included in the data unit, including generating the CRC field to include a portion of the CRC sequence;

generate the data unit to conform to the first communication protocol, including generating the data unit to include (i) the signal field and (ii) the CRC field that includes the portion of the CRC sequence such that the data unit does not include the entire CRC sequence.

9. The apparatus of claim 8, wherein the PHY processing unit is configured to truncate the CRC sequence to generate the portion of the CRC sequence.

10. The apparatus of claim 8, wherein the PHY processing unit is configured to

generate the CRC sequence at least by generating an 8-bit CRC sequence, and

generate the CRC field to include only four bits of the 8-bit CRC sequence.

11. The apparatus of claim 10, wherein PHY processing unit is configured to generate the CRC field to include only a last four bits of the 8-bit CRC sequence.

12. The apparatus of claim 8, wherein the first communication protocol defines a first number of signal field CRC bits that is less than a second number of signal field CRC bits defined by the second communication protocol, and wherein the PHY processing unit is configured to generate the data unit to use one or more bits that are defined as signal field CRC bits by the second communication protocol, but not by the first communication protocol, to include signal field data other than CRC data.

13. The apparatus of claim 8, wherein (i) the data unit is a first data unit, (ii) the signal field is a first signal field, (iii) the CRC sequence is a first CRC sequence and (iv) the CRC field is a first CRC field, and wherein the PHY processing unit is further configured to:

generate, using the generator polynomial, a second cyclic redundancy check (CRC) bit sequence based on information bits to be included in a second signal field, wherein the second signal field is to be included in a second data unit;

generate a second CRC field to be included in the second data unit, including generating the second CRC field to include the entire second CRC sequence;

generate the second data unit to include (i) the second signal field and (ii) the second CRC field, wherein the second data unit conforms to the second communication protocol.

14. The apparatus of claim 8, wherein PHY processing unit is configured to generate the data unit to include the signal field in a preamble of the data unit.

15. A method for detecting errors in data units, the method comprising:

receiving, at a network interface of a wireless network device, the network interface implemented on one or more integrated circuits, a data unit transmitted in a wireless network, wherein the data unit conforms to a first communication protocol;

generating, at the network interface of the wireless network device, a first CRC sequence based on information bits of a signal field included in the data unit, including generating the first CRC sequence using a CRC polynomial defined by a second communication protocol different from the first communication protocol;

generating, at the network interface of the wireless network device, a second CRC sequence based on the first CRC sequence, wherein the second CRC sequence (i) includes a portion of the first CRC sequence and (ii) does not include the entire first CRC sequence;

comparing, at the network interface of a communication device, the second CRC sequence with a CRC sequence included in the data unit; and

determining, at the network interface of a communication device, whether there are one or more errors in the signal field based on the comparison of the second CRC sequence with a CRC sequence included in the data unit.

16. The method of claim 15, wherein generating the second CRC sequence includes truncating the first CRC sequence to generate the portion of the first CRC sequence.

17. The method of claim 15, wherein generating the first CRC sequence comprises generating an 8-bit CRC sequence, and wherein generating the second CRC sequence comprises generating the second CRC sequence to consist of four bits of the 8-bit CRC sequence;

wherein the CRC sequence included in the data unit consists of four bits.

18. The method of claim 17, wherein generating the second CRC sequence comprises generating the second CRC sequence to include a last four bits of the 8-bit CRC sequence.

19. An apparatus, comprising:

a wireless network interface having one or more integrated circuits, the wireless network interface including;

a medium access control (MAC) processing unit implemented on the one or more integrated circuits, and

a physical layer (PHY) processing unit coupled to the MAC processing unit, the PHY processing unit implemented on the one or more integrated circuits;

wherein the PHY processing unit is configured to

generate a first CRC sequence based on information bits of a signal field included in a data unit received via a wireless network, wherein the data unit conforms to a first communication protocol, and wherein the PHY processing unit is configured to generate the first CRC sequence using a CRC polynomial defined by a second communication protocol different from the first communication protocol;

generate a second CRC sequence based on the first CRC sequence, wherein the second CRC sequence (i) includes a portion of the first CRC sequence and (ii) does not include the entire first CRC sequence;

compare the second CRC sequence with a CRC sequence included in the data unit; and

determine whether there are one or more errors in the signal field based on the comparison of the second CRC sequence with a CRC sequence included in the data unit.

20. The apparatus of claim 19, wherein the PHY processing unit is configured to truncate the first CRC sequence to generate the second CRC sequence.

21. The apparatus of claim 19, wherein the PHY processing unit is configured to

generate the first CRC sequence by generating an 8-bit CRC sequence, and

generate the second CRC sequence to consist of four bits of the 8-bit CRC sequence;

wherein the CRC sequence included in the signal field consists of four bits.

22. The apparatus of claim 20, wherein the PHY processing unit is configured generate the second CRC bit sequence to include a last four bits of the 8-bit CRC sequence.