Method for transmitting closely-spaced packets in WLAN devices and systems

Abstract

A wireless local area network (WLAN) device transmits multiple data packets within a data burst. In various embodiments, after the first packet is transmitted, subsequent packets are transmitted before expiration of an Interframe Space (IFS). The subsequent packets may have a full-length preamble, a partial preamble or no preamble at all.

1 . A method comprising:
 transmitting a first protocol data unit over an air interface, wherein the first protocol data unit includes
 a first preamble, which enables a receiver to synchronize, and which is transmitted at a first modulation rate; 
 a first header, following the first preamble, which is transmitted at the first modulation rate; and 
 a first service data unit, following the first header, which is transmitted at a second modulation rate; and 
   transmitting a second protocol data unit over the air interface before expiration of an interframe space.   
   
   
       2 . The method of  claim 1 , wherein transmitting the second protocol data unit begins approximately at a next symbol boundary after an end of transmitting the first protocol data unit. 
   
   
       3 . The method of  claim 1 , wherein the second protocol data unit includes:
 a second preamble, which is transmitted at the first modulation rate;   a second header, following the second preamble, which is transmitted at the first modulation rate; and   the second service data unit, following the second header, which is transmitted at a third modulation rate.   
   
   
       4 . The method of  claim 3 , wherein the first preamble includes a full-length preamble, and wherein the second preamble includes a partial preamble. 
   
   
       5 . The method of  claim 4 , wherein the first preamble consumes approximately two symbol widths, and wherein the second preamble consumes approximately one symbol width. 
   
   
       6 . The method of  claim 1 , wherein the second protocol data unit includes:
 a second header, which is transmitted at the first modulation rate; and   the second service data unit, following the second header, which is transmitted at a third modulation rate.   
   
   
       7 . The method of  claim 1 , wherein the interframe space is a time period from a group of time periods including a short interframe space, a priority interframe space, a distributed interframe space, and an extended interframe space, as defined in an IEEE 802.11 Standard. 
   
   
       8 . The method of  claim 1 , wherein the header includes a physical device header. 
   
   
       9 . The method of  claim 1 , wherein the first modulation rate is in a range of approximately 6 to 12 megabits per second. 
   
   
       10 . The method of  claim 1 , wherein the second modulation rate is in a range of approximately 6 to 240 megabits per second. 
   
   
       11 . A method comprising:
 receiving a first protocol data unit over an air interface, wherein the first protocol data unit includes
 a first preamble, which enables a receiver to synchronize, and which is received at a first modulation rate; 
 a first header, following the first preamble, which is received at the first modulation rate; and 
 the first service data unit, following the first header, which is received at a second modulation rate; and 
   receiving a second protocol data unit over the air interface before expiration of an interframe space.   
   
   
       12 . The method of  claim 11 , wherein the second protocol data unit includes:
 a second preamble, which is received at the first modulation rate;   a second header, following the second preamble, which is received at the first modulation rate; and   the second service data unit, following the second header, which is received at a third modulation rate.   
   
   
       13 . The method of  claim 12 , wherein the first preamble includes a full-length preamble, and wherein the second preamble includes a partial preamble. 
   
   
       14 . The method of  claim 13 , wherein the first preamble consumes approximately two symbol widths, and wherein the second preamble consumes approximately one symbol width. 
   
   
       15 . The method of  claim 11 , wherein the second protocol data unit includes:
 a second header, which is received at the first modulation rate; and   the second service data unit, following the second header, which is received at a third modulation rate.   
   
   
       16 . The method of  claim 15 , wherein the second header further includes a data integrity field, the method further comprising:
 determining whether the second header is valid using information in the data integrity field; and   if the second header is not valid, evaluating at least one header-sized data segment subsequently received to attempt to find another possible header.   
   
   
       17 . The method of  claim 11 , wherein the interframe space is a time period from a group of time periods including a short interframe space, a priority interframe space, a distributed interframe space, and an extended interframe space, as defined in an IEEE 802.11 Standard. 
   
   
       18 . The method of  claim 11 , wherein the header includes a physical device header. 
   
   
       19 . The method of  claim 11 , wherein the first modulation rate is in a range of approximately 6 to 12 megabits per second. 
   
   
       20 . The method of  claim 11 , wherein the second modulation rate is in a range of approximately 6 to 240 megabits per second. 
   
   
       21 . An apparatus comprising:
 a medium access control device, which is operable to provide multiple data units destined for a receiver to a physical device; and   the physical device, coupled to the medium access control device, which is operable to
 transmit a first protocol data unit over an air interface, wherein the first protocol data unit includes
 a first preamble, to enable a receiver to synchronize, and which the physical device is to transmit at a first modulation rate; 
 a first header, following the first preamble, which the physical device is to transmit at the first modulation rate; and 
 the first service data unit, following the first header, which the physical device is to transmit at a second modulation rate; and 
 
 transmit a second protocol data unit over the air interface before expiration of an interframe space. 
   
   
   
       22 . The apparatus of  claim 21 , wherein the physical device is further operable to transmit the second protocol data unit beginning approximately at a next symbol boundary after an end of transmitting the first protocol data unit. 
   
   
       23 . The apparatus of  claim 21 , wherein the second protocol data unit includes:
 a second preamble, which the physical device is to transmit at the first modulation rate;   a second header, following the second preamble, which the physical device is to transmit at the first modulation rate; and   the second service data unit, following the second header, which the physical device is to transmit at a third modulation rate.   
   
   
       24 . The apparatus of  claim 23 , wherein the first preamble includes a full-length preamble, and wherein the second preamble includes a partial preamble. 
   
   
       25 . The apparatus of  claim 24 , wherein the first preamble consumes approximately two symbol widths, and wherein the second preamble consumes approximately one symbol width. 
   
   
       26 . The apparatus of  claim 21 , wherein the second protocol data unit includes:
 a second header, which the physical device is to transmit at the first modulation rate; and   the second service data unit, following the second header, which the physical device is to transmit at a third modulation rate.   
   
   
       27 . The apparatus of  claim 21 , wherein the interframe space is a time period from a group of time periods including a short interframe space, a priority interframe space, a distributed interframe space, and an extended interframe space, as defined in an IEEE 802.11 Standard. 
   
   
       28 . The apparatus of  claim 21 , further comprising one or more antennae, coupled to the physical device, which are operable to provide an interface between the air interface and the physical device. 
   
   
       29 . The apparatus of  claim 21 , further comprising an optical transmission device, coupled to the physical device, which is operable to provide an interface between the air interface and the physical device. 
   
   
       30 . An apparatus comprising:
 a medium access control device, which is operable to receive multiple data units from a physical device; and   the physical device, coupled to the medium access control device, which is operable to
 receive a first protocol data unit over an air interface, wherein the first protocol data unit includes
 a first preamble, to enable a receiver to synchronize, and which the physical device is to receive at a first modulation rate; 
 a first header, following the first preamble, which the physical device is to receive at the first modulation rate; and 
 the first service data unit, following the first header, which the physical device is to receive at a second modulation rate; and 
 
 receive a second protocol data unit over the air interface before expiration of an interframe space. 
   
   
   
       31 . The apparatus of  claim 30 , wherein the second protocol data unit includes:
 a second preamble, which the physical device is to receive at the first modulation rate;   a second header, following the second preamble, which the physical device is to receive at the first modulation rate; and   the second service data unit, following the second header, which the physical device is to receive at a third modulation rate.   
   
   
       32 . The apparatus of  claim 31 , wherein the first preamble includes a full-length preamble, and wherein the second preamble includes a partial preamble. 
   
   
       33 . The apparatus of  claim 32 , wherein the first preamble consumes approximately two symbol widths, and wherein the second preamble consumes approximately one symbol width. 
   
   
       34 . The apparatus of  claim 30 , wherein the second protocol data unit includes:
 a second header, which the physical device is to receive at the first modulation rate; and   the second service data unit, following the second header, which the physical device is to receive at a third modulation rate.   
   
   
       35 . The apparatus of  claim 34 , wherein the second header further includes a data integrity field, and wherein the physical device is further operable to:
 determine whether the second header is valid using information in the data integrity field; and   if the second header is not valid, evaluate at least one header-sized data segment subsequently received to attempt to find another possible header.   
   
   
       36 . The apparatus of  claim 30 , wherein the interframe space is a time period from a group of time periods including a short interframe space, a priority interframe space, a distributed interframe space, and an extended interframe space, as defined in an IEEE 802.11 Standard. 
   
   
       37 . The apparatus of  claim 30 , wherein the header includes a physical device header. 
   
   
       38 . The apparatus of  claim 30 , further comprising one or more antennae, coupled to the physical device, which is operable to provide an interface between the air interface and the physical device. 
   
   
       39 . The apparatus of  claim 30 , further comprising an optical transmission device, coupled to the physical device, which is operable to provide an interface between the air interface and the physical device. 
   
   
       40 . A computer-readable medium having program instructions stored thereon to perform a method, which when executed within a wireless local area network device, result in:
 transmitting a first protocol data unit over an air interface, wherein the first protocol data unit includes
 a first preamble, which enables a receiver to synchronize, and which is transmitted at a first modulation rate; 
 a first header, following the first preamble, which is transmitted at the first modulation rate; and 
 the first service data unit, following the first header, which is transmitted at a second modulation rate; and 
   transmitting a second protocol data unit over the air interface before expiration of an interframe space.   
   
   
       41 . The computer-readable medium of  claim 40 , wherein transmitting the second protocol data unit begins approximately at a next symbol boundary after an end of transmitting the first protocol data unit. 
   
   
       42 . The computer-readable medium of  claim 40 , wherein the second protocol data unit includes:
 a second preamble, which is transmitted at the first modulation rate;   a second header, following the second preamble, which is transmitted at the first modulation rate; and   the second service data unit, following the second header, which is transmitted at a third modulation rate.   
   
   
       43 . The computer-readable medium of  claim 42 , wherein the first preamble includes a full-length preamble, and wherein the second preamble includes a partial preamble. 
   
   
       44 . The computer-readable medium of  claim 43 , wherein the first preamble consumes approximately two symbol widths, and wherein the second preamble consumes approximately one symbol width. 
   
   
       45 . The computer-readable medium of  claim 40 , wherein the second protocol data unit includes:
 a second header, which is transmitted at the first modulation rate; and   the second service data unit, following the second header, which is transmitted at a third modulation rate.   
   
   
       46 . A computer-readable medium having program instructions stored thereon to perform a method, which when executed within a wireless local area network device, result in:
 receiving a first protocol data unit over an air interface, wherein the first protocol data unit includes
 a first preamble, which enables a receiver to synchronize, and which is received at a first modulation rate; 
 a first header, following the first preamble, which is received at the first modulation rate; and 
 the first service data unit, following the first header, which is received at a second modulation rate; and 
   receiving a second protocol data unit over the air interface before expiration of an interframe space.   
   
   
       47 . The computer-readable medium of  claim 46 , wherein the second protocol data unit includes:
 a second preamble, which is received at the first modulation rate;   a second header, following the second preamble, which is received at the first modulation rate; and   the second service data unit, following the second header, which is received at a third modulation rate.   
   
   
       48 . The computer-readable medium of  claim 47 , wherein the first preamble includes a full-length preamble, and wherein the second preamble includes a partial preamble. 
   
   
       49 . The computer-readable medium of  claim 48 , wherein the first preamble consumes approximately two symbol widths, and wherein the second preamble consumes approximately one symbol width. 
   
   
       50 . The computer-readable medium of  claim 46 , wherein the second protocol data unit includes:
 a second header, which is received at the first modulation rate; and   the second service data unit, following the second header, which is received at a third modulation rate.   
   
   
       51 . The computer-readable medium of  claim 46 , wherein the second header further includes a data integrity field, and executing the program instructions further results in:
 determining whether the second header is valid using information in the data integrity field; and   if the second header is not valid, evaluating at least one header-sized data segment subsequently received to attempt to find another possible header.