if (!bNeedAck)
                return uDataTime;
 
-       if (byPktType == PK_TYPE_11B) /* llb,CCK mode */
-               uAckTime = bb_get_frame_time(pDevice->byPreambleType, byPktType, 14, (unsigned short)pDevice->byTopCCKBasicRate);
-       else /* 11g 2.4G OFDM mode & 11a 5G OFDM mode */
-               uAckTime = bb_get_frame_time(pDevice->byPreambleType, byPktType, 14, (unsigned short)pDevice->byTopOFDMBasicRate);
+       /*
+        * CCK mode  - 11b
+        * OFDM mode - 11g 2.4G & 11a 5G
+        */
+       uAckTime = bb_get_frame_time(pDevice->byPreambleType, byPktType, 14,
+                                    byPktType == PK_TYPE_11B ?
+                                    pDevice->byTopCCKBasicRate :
+                                    pDevice->byTopOFDMBasicRate);
 
        return uDataTime + pDevice->uSIFS + uAckTime;
 }