5G/NR - MAC CE                                                                                Home : www.sharetechnote.com

 

 

 

 

 

MAC CE - Buffer Status Report MAC CEs  

 

The functionality of BSR in NR is exactly sa the LTE BSR. For the BSR functionality, refer to LTE BSR page. The dfference is the structure of MAC CE and the length of Buffer Size Bit field. It is understandable that the length of the BSR bit field in NR would be longer than LTE BSR. Another difference is that NR BSR has explcit bit field for LCG as shown below whereas LTE BSR specifies LCG implcitely.

 

 

<  38.321-Figure 6.1.3.1-1: Short BSR and Short Truncated BSR MAC CE >

 

 

<  38.321-Figure 6.1.3.1-2: Long BSR and Long Truncated BSR MAC CE >

 

 

<  38.321-Table 6.1.3.1-1: Buffer size levels (in bytes) for 5-bit Buffer Size field >

 

 

<  38.321-Table 6.1.3.1-2: Buffer size levels (in bytes) for 8-bit Buffer Size field >

 

 

 

RRC Parameters for BSR

 

 

MAC-CellGroupConfig ::= SEQUENCE {

   drx-Config                   SetupRelease { DRX-Config } OPTIONAL, -- Need M

   schedulingRequestConfig      SchedulingRequestConfig OPTIONAL, -- Need M

   bsr-Config                   BSR-Config OPTIONAL, -- Need M

   tag-Config                   TAG-Config OPTIONAL, -- Need M

   phr-Config                   SetupRelease { PHR-Config } OPTIONAL, -- Need M

   skipUplinkTxDynamic          BOOLEAN,

   ...,

   [[

   csi-Mask-v1530               BOOLEAN OPTIONAL , -- Need M

   dataInactivityTimer-v1530    SetupRelease { DataInactivityTimer } OPTIONAL -- Need

   PCellOnly

   ]]

}

 

 

BSR-Config ::= SEQUENCE {

   periodicBSR-Timer              ENUMERATED { sf1, sf5, sf10, sf16, sf20, sf32, sf40, sf64,

                                               sf80, sf128, sf160, sf320, sf640, sf1280,

                                               sf2560, infinity },

   retxBSR-Timer                  ENUMERATED { sf10, sf20, sf40, sf80, sf160, sf320, sf640,

                                               sf1280, sf2560,sf5120, sf10240, spare5, spare4,

                                               spare3, spare2, spare1},

   logicalChannelSR-DelayTimer    ENUMERATED { sf20, sf40, sf64, sf128, sf512, sf1024,

                                               sf2560, spare1} OPTIONAL, -- Need R

...

}

 

 

 

Reference

 

[1]