Methods and media access controller for broadband wireless communications with variable data unit size and delayed data unit construction

Abstract

A media access controller (MAC) of a broadband wireless communication device may vary the size of data unit payloads based on a physical layer burst size. In automatic retransmission request (ARQ) enabled service flows, the MAC may delay construction of data units from the data unit payloads until after entering an ARQ retransmission request window. In some embodiments, the MAC comprises per-flow schedulers to schedule service data units (SDUs) for each of a plurality of service flows, and per-service flow retransmission request handlers to reconstruct and retransmit data units.

1 . A media access controller (MAC) for a wireless access network communication device, the MAC comprising:
 a data unit constructor to delay construction of data units for service flows having automatic retransmission requests (ARQs) enabled and to refrain from delaying construction of data units for service flows that do not have ARQs enabled; and   a per flow scheduler to vary a size of the data units for service flows having ARQs enabled based on a stability of a wireless channel.   
   
   
       2 . The MAC of  claim 1  wherein the data unit constructor delays construction of data units for service flows having ARQs enabled by constructing data units after data unit payloads enter a retransmission request window. 
   
   
       3 . The MAC of  claim 2  wherein the retransmission request window comprises a buffer to reference previously transmitted data units, the buffer to advance either after one of the transmitted data units is acknowledged as being received or after a predetermined period of time, and
 wherein the data unit payload enters the retransmission request window after the buffer advances.   
   
   
       4 . The MAC of  claim 1  wherein for service flows having ARQs enabled, a size of unsuccessfully transmitted data units is reduced when channel conditions degrade. 
   
   
       5 . The MAC of  claim 4  wherein the data unit constructor comprises a retransmission request handler to reconstruct data units from data unit payloads for subsequent retransmission within physical-layer bursts,
 wherein for service flows having ARQs enabled, the retransmission request handler reconstructs data units from portions of previously transmitted data units that are not acknowledged as being received, and   wherein a size of unsuccessfully transmitted data units is reduced when channel conditions degrade.   
   
   
       6 . The MAC of  claim 2  wherein the stability of the wireless channel is indicated by a rate at which a burst size is changed by a physical layer. 
   
   
       7 . The MAC of  claim 6  wherein the physical layer is configured to initially set a physical-layer burst size based on channel conditions and to change the physical-layer burst size in response to changing channel conditions. 
   
   
       8 . A wireless communication device for operation in a wireless access network, the wireless communication device comprising:
 a media access controller (MAC) to delay construction of data units for service flows having automatic retransmission requests (ARQs) enabled and to refrain from delaying construction of data units for service flows that do not have ARQs enabled; and   a physical layer to provide an indication of channel stability to the MAC, wherein the MAC is configured to vary a size of the data units for service flows having ARQs enabled based on the indication of channel stability.   
   
   
       9 . The wireless communication device of  claim 8  wherein the MAC is configured to delay construction of data units for service flows having ARQs enabled by constructing data units after data unit payloads enter a retransmission request window. 
   
   
       10 . The wireless communication device of  claim 9  wherein the retransmission request window comprises a buffer to reference previously transmitted data units, the buffer to advance either after one of the transmitted data units is acknowledged as being received or after a predetermined period of time, and
 wherein the data unit payload enters the retransmission request window after the buffer advances.   
   
   
       11 . The wireless communication device of  claim 8  wherein for service flows having ARQs enabled, a size of unsuccessfully transmitted data units is reduced when channel conditions degrade. 
   
   
       12 . The wireless communication device of  claim 11  wherein the MAC is further configured to reconstruct data units from data unit payloads for subsequent retransmission within physical-layer bursts,
 wherein for service flows having ARQs enabled, the MAC is configured to reconstruct data units from portions of previously transmitted data units that are not acknowledged as being received, and   wherein a size of unsuccessfully transmitted data units is reduced when channel conditions degrade.   
   
   
       13 . The wireless communication device of  claim 9  wherein the indication of channel stability is a rate at which a burst size is changed by the physical layer. 
   
   
       14 . The wireless communication device of  claim 13  wherein the physical layer is configured to initially set a physical-layer burst size based on channel conditions and to change the physical-layer burst size in response to changing channel conditions. 
   
   
       15 . A method for generating data units for transmission in physical-layer bursts, the method comprising:
 delaying construction of data units for service flows having automatic retransmission requests (ARQs) enabled;   refraining from delaying construction of data units for service flows that do not have ARQs enabled; and   varying a size of the data units for service flows having ARQs enabled based on a stability of a wireless channel.   
   
   
       16 . The method of  claim 15  wherein the construction of data units for service flows having ARQs enabled is delayed by constructing data units after data unit payloads enter a retransmission request window. 
   
   
       17 . The method of  claim 16  wherein the retransmission request window comprises a buffer to reference previously transmitted data units,
 wherein the method comprises advancing the buffer either after one of the transmitted data units is acknowledged as being received or after a predetermined period of time, and   wherein the data unit payload enters the retransmission request window after the buffer is advanced.   
   
   
       18 . The method of  claim 15  further comprising reducing a size of unsuccessfully transmitted data units for service flows having ARQs enabled when channel conditions degrade. 
   
   
       19 . The method of  claim 18  further comprising:
 reconstructing data units from data unit payloads for subsequent retransmission within physical-layer bursts;   reconstructing data units from portions of previously transmitted data units that are not acknowledged as being received for service flows having ARQs enabled; and   reducing a size of unsuccessfully transmitted data units when channel conditions degrade.   
   
   
       20 . The method of  claim 16  further comprising:
 indicating the stability of the wireless channel by a rate at which a burst size is changed;   initially setting a physical-layer burst size based on channel conditions; and   changing the physical-layer burst size in response to changing channel conditions.