Methods and Apparatus for WLAN Transmission

• US 20110026623A1
• Filed: 07/29/2010
• Published: 02/03/2011
• Est. Priority Date: 07/29/2009
• Status: Active Grant

• Current Assignee: Marvell Asia Pte Limited (Marvell Technology Group Limited)
• Original Assignee: Marvell World Trade Limited (Marvell Technology Group Limited)
• Inventors: Zhang, Hongyuan, Nabar, Rohit U., Srinivasa, Sudhir
• Granted Patent: US 8,724,720 B2
• Time in Patent Office: Days
• US Class Current: 375/260
• CPC Class Codes: H04L 1/0005 applied to payload information
• CPC Class Codes: H04L 1/0016 involving special memory structures, e.g. look-up tables
• CPC Class Codes: H04L 27/2607 Cyclic extensions
• CPC Class Codes: H04L 27/34 Amplitude- and phase-modulated carrier systems, e.g. quadrature-amplitude modulated carrier systems
• CPC Class Codes: H04W 84/12 WLAN [Wireless Local Area Networks]

Abstract

In a method for generating a physical layer (PHY) data unit for transmission via a communication channel, a first set of modulation coding schemes (MCSs) and a second set of MCSs that correspond to a number of spatial streams and a number of encoders are provided. The first set of MCSs correspond to a first channel bandwidth and the second set of MCSs correspond to a second channel bandwidth, and the first set of MCSs is different than the second set of MCSs. An MCS is selected from the first set of MCSs when the PHY data unit is to be transmitted using a channel having the first channel bandwidth, and the MCS is selected from the second set of MCSs when the PHY data unit is to be transmitted using a channel having the second channel bandwidth. Information bits are encoded using the number of encoders and according to the selected MCS, and the encoded information bits are parsed into the number of spatial streams. The encoded information bits are modulated according to the MCS, and a plurality of OFDM symbols are formed based on the modulated encoded information bits.

Claims

1. A method for generating a physical layer (PHY) data unit for transmission via a communication channel, the method comprising:

providing a first set of modulation coding schemes (MCSs) and a second set of MCSs that correspond to a number of spatial streams and a number of encoders, wherein the first set of MCSs correspond to a first channel bandwidth and the second set of MCSs correspond to a second channel bandwidth, and wherein the first set of MCSs is different than the second set of MCSs;

selecting an MCS from the first set of MCSs when the PHY data unit is to be transmitted using a channel having the first channel bandwidth;

selecting the MCS from the second set of MCSs when the PHY data unit is to be transmitted using a channel having the second channel bandwidth;

encoding information bits using the number of encoders and according to the selected MCS;

parsing the encoded information bits into the number of spatial streams;

modulating the encoded information bits according to the MCS; and

forming a plurality of OFDM symbols based on the modulated encoded information bits.

2. A method according to claim 1, wherein:

providing the first set of MCSs comprises providing a first MCS table;

providing the second set of MCSs comprises providing a second MCS table; and

the first MCS table is different than the second MCS table.

3. A method according to claim 1, wherein providing the first set of MCSs and the second set of MCSs comprises providing an MCS table, wherein the MCS table is interpreted differently when the PHY data unit is to be transmitted using the first channel bandwidth as compared to when the PHY data unit is to be transmitted using the second channel bandwidth.

4. A method according to claim 1, wherein:

the first set of MCSs excludes MCSs that will result in a padding-related constraint not being met when the first channel bandwidth is to be used;

the second set of MCSs excludes MCSs that will result in a padding-related constraint not being met the second channel bandwidth is to be used; and

the method further comprises adding padding bits to the information bits.

5. A method according to claim 4, further comprising parsing the information bits to a plurality of encoders;

wherein adding padding bits to the information bits includes adding first padding bits prior parsing the information bits to the plurality of encoders.

6. A method according to claim 5, wherein adding padding bits to the information bits includes adding second padding bits after parsing the information bits to the plurality of encoders.

7. A physical layer (PHY) apparatus for generating a PHY data unit for transmission via a communication channel, the PHY apparatus comprising:

a memory to store indicators of a first set of modulation coding schemes (MCSs) and a second set of MCSs that correspond to a number of spatial streams and a number of encoders, wherein the first set of MCSs correspond to a first channel bandwidth and the second set of MCSs correspond to a second channel bandwidth, and wherein the first set of MCSs is different than the second set of MCSs;

wherein the PHY apparatus is configured to i) select an MCS from the first set of MCSs when the PHY data unit is to be transmitted using a channel having the first channel bandwidth, and ii) select the MCS from the second set of MCSs when the PHY data unit is to be transmitted using a channel having the second channel bandwidth;

wherein the PHY apparatus further comprises;

a plurality of encoders to encode information bits according to the number of encoders and according to the selected MCS;

a stream parser to parse the information bits into the number of spatial streams; and

a plurality of modulators to modulate the encoded information bits according to the MCS;

wherein the PHY apparatus is configured to form a plurality of OFDM symbols based on the modulated encoded information bits.

8. An apparatus according to claim 7, wherein the memory includes i) a first MCS table having the first set of MCSs, and ii) a second MCS table having the second set of MCSs;

wherein the first MCS table is different than the second MCS table.

9. An apparatus according to claim 7, wherein the memory includes an MCS table;

wherein the PHY apparatus is configured to interpret the MCS table differently when the PHY data unit is to be transmitted using the first channel bandwidth as compared to when the PHY data unit is to be transmitted using the second channel bandwidth.

10. An apparatus according to claim 7, wherein the first set of MCSs excludes MCSs that will result in a padding-related constraint not being met when the first channel bandwidth is to be used, and the second set of MCSs excludes MCSs that will result in a padding-related constraint not being met the second channel bandwidth is to be used;

wherein the apparatus further comprises a padding system to add padding bits to the information bits.

11. An apparatus according to claim 10, further comprising an encoder parser to parse the information bits to a plurality of encoders;

wherein the padding system includes a first padding unit to add first padding bits prior parsing the information bits to the plurality of encoders.

12. An apparatus according to claim 11, wherein the padding system includes a second padding unit to add second padding bits after parsing the information bits to the plurality of encoders.

13. A method for generating a physical layer (PHY) data unit for transmission via a communication channel, the method comprising:

selecting a modulation scheme from a plurality of modulation schemes;

encoding information bits to generate encoded data using one or more encoders;

selecting an interleaving parameter N_COL using the selected modulation scheme, wherein N_COL varies for different modulation schemes;

interleaving the encoded data, including entering the encoded data into N_ROW rows and reading the encoded data out in N_COL columns;

modulating the payload information of the PHY data unit according to the modulation scheme; and

forming a plurality of OFDM symbols based on the modulated payload information.

14. A method according to claim 13, further comprising selecting the parameter N_ROW using the selected modulation scheme, wherein N_ROW is the same for some modulation schemes.

15. A method according to claim 13, further comprising:

selecting a number of spatial streams; and

parsing the encoded data into the number of spatial streams.

16. A method according to claim 15, further comprising:

selecting an interleaving parameter N_ROT using the selected number of spatial streams, wherein N_ROT varies for different numbers of spatial streams;

wherein interleaving the encoded data comprises applying a frequency rotation according to N_ROT.

17. A physical layer (PHY) apparatus for generating a PHY data unit for transmission via a communication channel, the PHY apparatus comprising:

a memory to store indicators of a plurality of modulation schemes;

wherein the PHY apparatus is configured to i) select a modulation scheme from the plurality of modulation schemes, and ii) select an interleaving parameter N_COL using the selected modulation scheme, wherein N_COL varies for different modulation schemes;

wherein the PHY apparatus further comprises;

one or more encoders to encode information bits to generate encoded data;

an interleaver to interleave the encoded data, including entering the encoded data into N_ROW rows and reading the encoded data out in N_COL columns; and

one or more modulators to modulate the encoded information bits according to the selected modulation scheme;

wherein the PHY apparatus is configured to form a plurality of OFDM symbols based on the modulated encoded information bits.

18. An apparatus according to claim 17, wherein the PHY apparatus is configured to select the parameter N_ROW using the selected modulation scheme, wherein N_ROW is the same for some modulation schemes.

19. An apparatus according to claim 17, wherein the PHY apparatus is configured to select a number of spatial streams;

and

wherein the PHY apparatus comprises a stream parser to parse the encoded data into the number of spatial streams.

20. An apparatus according to claim 19, wherein the PHY apparatus is configured to select an interleaving parameter N_ROT using the selected number of spatial streams, wherein N_ROT varies for different numbers of spatial streams;

wherein the interleaver is configured to apply a frequency rotation according to N_ROT.