Efficient transmission for low data rate WLAN

• US 8,995,367 B2
• Filed: 06/08/2012
• Issued: 03/31/2015
• Est. Priority Date: 06/08/2011
• Status: Active Grant

• Current Assignee: Marvell Asia Pte Limited (Marvell Technology Group Limited)
• Original Assignee: Marvell World Trade Limited (Marvell Technology Group Limited)
• Inventors: Liu, Yong
• Primary Examiner(s): Pham, Chi H
• Assistant Examiner(s): HYUN, SOON D
• Application Number:
  US13/492,452
• Publication Number:
  US 20120314695A1
• Time in Patent Office: 1,026 Days
• Field of Search: None
• US Class Current: 370/329
• CPC Class Codes: H04W 16/14 Spectrum sharing arrangements between different networks
• CPC Class Codes: H04W 28/065 using assembly or disassembly of packets
• CPC Class Codes: H04W 28/18 Negotiating wireless communication parameters
• CPC Class Codes: H04W 84/12 WLAN [Wireless Local Area Networks]
• CPC Class Codes: Y02D 30/70 in wireless communication networks

Abstract

A network interface device utilizes a physical layer (PHY) protocol data unit (PPDU) maximum duration such that, (A) when operating in a first mode of operation, a data unit (i) defined by a protocol in a layer above a PHY protocol in a protocol stack and (ii) having a maximum length defined by the protocol above the PHY protocol will fit entirely within a single PPDU at a lowest possible data rate in the first mode of operation, and (B) when operating in a second mode of operation, the data unit (i) defined by the protocol in the layer above the PHY protocol and (ii) having the maximum length defined by the protocol above the PHY protocol will not fit entirely within a single PPDU at a lowest possible data rate in the second mode of operation.

Claims

1. A method, comprising:

utilizing, at a network interface device, a physical layer (PHY) protocol data unit (PPDU) maximum duration defined by a PHY protocol such that, (A) when operating in a first mode of operation, a data unit (i) defined by a protocol in a layer above the PHY protocol in a protocol stack and (ii) having a maximum length defined by the protocol above the PHY protocol will fit entirely within a single PPDU at a lowest possible data rate defined by the PHY protocol in the first mode of operation, and (B) when operating in a second mode of operation, the data unit (i) defined by the protocol in the layer above the PHY protocol and (ii) having the maximum length defined by the protocol above the PHY protocol will not fit entirely within a single PPDU at a lowest possible data rate in the second mode of operation;

receiving medium access control (MAC) service data units (MSDUs);

generating, at the network interface, MAC protocol data units (MPDUs) to include the MSDUs;

when operating in the second mode of operation,

generating MPDUs includes, for each received MSDU,

determining whether a length of the MSDU exceeds a fragmentation threshold,

fragmenting the MSDU into multiple MPDUs when it is determined that the length of the MSDU exceeds the fragmentation threshold, and

generating a single MPDU that includes the MSDU when it is determined that the length of the MSDU does not exceed the fragmentation threshold,

wherein the fragmentation threshold is determined based on a maximum MPDU size that will fit entirely within a single PPDU at the lowest possible data rate in the second mode of operation;

generating, at the network interface device, PHY protocol data units (PPDUs) to include the MPDUs, wherein each PPDU has a duration less than or equal to the PPDU maximum duration; and

causing the PPDUs to be transmitted.

2. A method according to claim 1, wherein

the fragmentation threshold is first fragmentation threshold, and

when operating in the second mode of operation,

generating MPDUs includes, for each received MSDU,

determining whether a length of the MSDU exceeds a second fragmentation threshold,

fragmenting the MSDU into multiple MPDUs when it is determined that the length of the MSDU exceeds the second fragmentation threshold, and

generating a single MPDU that includes the MSDU when it is determined that the length of the MSDU does not exceed the second fragmentation threshold.

3. A method according to claim 2, wherein the second fragmentation threshold is larger than the first fragmentation threshold.

4. An apparatus comprising:

a network interface configured to

utilize a physical layer (PHY) protocol data unit (PPDU) maximum duration defined by a PHY protocol such that, (A) when operating in a first mode of operation, a data unit (i) defined by a protocol in a layer above the PHY protocol in a protocol stack and (ii) having a maximum length defined by the protocol above the PHY protocol will fit entirely within a single PPDU at a lowest possible data rate defined by the PHY protocol in the first mode of operation, and (B) when operating in a second mode of operation, the data unit (i) defined by the protocol in the layer above the PHY protocol and (ii) having the maximum length defined by the protocol above the PHY protocol will not fit entirely within a single PPDU at a lowest possible data rate in the second mode of operation;

wherein the network interface includes a medium access control (MAC) processing unit configured to

generate MAC protocol data units (MPDUs) to include medium access control (MAC) service data units (MPDUs), wherein

when operating in the second mode of operation, the MAC processing unit is configured to, for each MSDU,

determine whether a length of the MSDU exceeds a fragmentation threshold, fragment the MSDU into multiple MPDUs when it is determined that the length of the MSDU exceeds the fragmentation threshold, and

generate a single MPDU that includes the MSDU when it is determined that the length of the MSDU does not exceed the fragmentation threshold,

wherein the fragmentation threshold is determined based on a maximum MPDU size that will fit entirely within a single PPDU at the lowest possible data rate in the second mode of operation; and

wherein the network interface further includes a PHY processing unit configured to

generate PHY protocol data units (PPDUs) to include the MPDUs, wherein each PPDU has a duration less than or equal to the PPDU maximum duration, and

cause the PPDUs to be transmitted.

5. An apparatus according to claim 4, wherein

the fragmentation threshold is first fragmentation threshold, and the MAC processing unit, when operating in the second mode of operation, is configured to, for each MSDU,

determine whether a length of the MSDU exceeds a second fragmentation threshold, fragment the MSDU into multiple MPDUs when it is determined that the length of the MSDU exceeds the second fragmentation threshold, and

generate a single MPDU that includes the MSDU when it is determined that the length of the MSDU does not exceed the second fragmentation threshold.

6. An apparatus according to claim 5, wherein the second fragmentation threshold is larger than the first fragmentation threshold.

7. A method, comprising:

receiving a medium access control (MAC) service data unit (MSDU);

determining whether (i) the MSDU is to be transmitted according to a first mode of operation, or (ii) the MSDU is to be transmitted in according to a second mode of operation, wherein the second mode of operation corresponds to longer range transmission than the first mode of operation;

when the MSDU is to be transmitted according to a first mode of operation,

determining whether a length of the MSDU exceeds a first fragmentation threshold corresponding to the first mode of operation,

fragmenting the MSDU into multiple MAC protocol data units (MPDUs) when it is determined that the length of the MSDU exceeds the first fragmentation threshold, and

generating an MPDU that includes the MSDU when it is determined that the length of the MSDU does not exceed the first fragmentation threshold; and

when the MSDU is to be transmitted according to a second mode of operation,

determining whether the length of the MSDU exceeds a second fragmentation threshold corresponding to the second mode of operation,

fragmenting the MSDU into multiple MPDUs when it is determined that the length of the MSDU exceeds the second fragmentation threshold, and

generating the MPDU that includes the MSDU when it is determined that the length of the MSDU does not exceed the second fragmentation threshold.

8. A method according to claim 7, wherein the first fragmentation threshold is determined based on a lowest possible data rate defined by a physical layer (PHY) protocol in the first mode of operation.

9. A method according to claim 8, wherein:

the second fragmentation threshold is determined based on a lowest possible data rate defined by the PHY protocol in the second mode of operation, and

the second fragmentation threshold is smaller than the first fragmentation threshold.

10. A method according to claim 7, wherein:

the first mode of operation includes a plurality of first possible data rates defined by a physical layer (PHY) protocol including a first lowest possible data rate in the first mode of operation,

the second mode of operation includes a plurality of second possible data rates defined by the PHY protocol including a second lowest possible data rate in the second mode of operation, and

the second lowest possible data rate is lower than the first lowest possible data rate.

11. A method according to claim 7, wherein the second mode of operation corresponds to generating physical layer (PHY) data units at a first clock rate that is lower than a second clock rate at which PHY data units are generated in the first mode of operation.

12. An apparatus comprising:

a network interface configured to

determine whether (i) a medium access control (MAC) service data unit (MSDU) is to be transmitted according to a first mode of operation, or (ii) the MSDU is to be transmitted in according to a second mode of operation, wherein the second mode of operation corresponds to longer range transmission than the first mode of operation;

wherein the network interface includes a MAC processing unit configured to

when the MSDU is to be transmitted according to a first mode of operation,

determine whether a length of the MSDU exceeds the a first fragmentation threshold corresponding to the first mode of operation,

fragment the MSDU into multiple MAC protocol data units (MPDUs) when it is determined that the length of the MSDU exceeds the first fragmentation threshold, and

generate an MPDU that includes the MSDU when it is determined that the length of the MSDU does not exceed the first fragmentation threshold, and

when the MSDU is to be transmitted according to a second mode of operation,

determine whether the length of the MSDU exceeds a second fragmentation threshold corresponding to the second mode of operation,

fragment the MSDU into multiple MPDUs when it is determined that the length of the MSDU exceeds the second fragmentation threshold, and

generate the MPDU that includes the MSDU when it is determined that the length of the MSDU does not exceed the second fragmentation threshold.

13. An apparatus according to claim 12, wherein the first fragmentation threshold is determined based on a lowest possible data rate defined by a physical layer (PHY) protocol in the first mode of operation.

14. An apparatus according to claim 13, wherein:

the second fragmentation threshold is determined based on a lowest possible data rate defined by the PHY protocol in the second mode of operation; and

the second fragmentation threshold is smaller than the first fragmentation threshold.

15. An apparatus according to claim 12, wherein:

the first mode of operation includes a plurality of first possible data rates defined by a physical layer (PHY) protocol including a first lowest possible data rate in the first mode of operation;

the second mode of operation includes a plurality of second possible data rates defined by the PHY protocol including a second lowest possible data rate in the second mode of operation; and

the second lowest possible data rate is lower than the first lowest possible data rate.

16. An apparatus according to claim 12, wherein the second mode of operation corresponds to generating physical layer (PHY) data units at a first clock rate that is lower than a second clock rate at which PHY data units are generated in the first mode of operation.

17. A method, comprising:

when operating in a first mode of operation, utilizing a first physical layer (PHY) protocol data unit (PPDU) maximum duration defined by a PHY protocol so that a data unit (i) defined by a protocol in a layer above the PHY protocol in a protocol stack and (ii) having a maximum length defined by the protocol above the PHY will fit entirely within a single PPDU at a lowest possible data rate defined by the PHY protocol in the first mode of operation; and

when operating in a second mode of operation, utilizing a second PPDU maximum duration defined by the PHY protocol so that a data unit (i) defined by the protocol in the layer above the PHY protocol and (ii) having the maximum length defined by the protocol above the PHY will not fit entirely within a single PPDU at a lowest possible data rate defined by the PHY protocol in the second mode of operation.

18. A method according to claim 17, wherein:

the first mode of operation includes a plurality of first possible data rates defined by the PHY protocol including the first lowest possible data rate in the first mode of operation;

the second mode of operation includes a plurality of second possible data rates defined by PHY protocol including the second lowest possible data rate in the second mode of operation; and

the second lowest possible data rate is lower than the first lowest possible data rate.

19. A method according to claim 17, wherein the second mode of operation corresponds to generating PPDUs at a first clock rate that is lower than a second clock rate at which PPDUs are generated in the first mode of operation.

20. An apparatus comprising:

a network interface configured to

when operating in a first mode of operation, utilize a first physical layer (PHY) protocol data unit (PPDU) maximum duration defined by a physical layer (PHY) protocol so that a data unit (i) defined by a protocol in a layer above a PHY protocol in a protocol stack and (ii) having a maximum length defined by the protocol above the PHY will fit entirely within a single PPDU at a lowest possible data rate defined by the PHY protocol in the first mode of operation, and

when operating in a second mode of operation, utilize a second PPDU maximum duration defined by the PHY protocol so that a data unit (i) defined by the protocol in the layer above the PHY protocol and (ii) having the maximum length defined by the protocol above the PHY will not fit entirely within a single PPDU at a lowest possible data rate defined by the PHY protocol in the second mode of operation,

wherein the network interface includes a PHY processing unit configured to

when operating in the first mode of operation, generate PPDUs that have respective durations that do not exceed the first PPDU maximum duration, and

when operating in the second mode of operation, generate PPDUs that have respective durations that do not exceed the second PPDU maximum duration.

21. An apparatus according to claim 20, wherein:

the first mode of operation includes a plurality of first possible data rates defined by the PHY protocol including the first lowest possible data rate in the first mode of operation;

the second mode of operation includes a plurality of second possible data rates defined by the PHY protocol including the second lowest possible data rate in the second mode of operation; and

the second lowest possible data rate is lower than the first lowest possible data rate.

22. An apparatus according to claim 20, wherein the second mode of operation corresponds to generating PPDUs at a first clock rate that is lower than a second clock rate at which PPDUs are generated in the first mode of operation.