Certain aspects of the present disclosure relate to techniques and apparatus for efficient support of variable bit rate (VBR) voice traffic on LTE uplink. In an aspect, a base station may periodically schedule transmission resources for use by a user equipment (UE) for transmitting data on a logical channel, wherein the periodically scheduling grants the UE a fixed first transport block (TB) size of transmission resources at regular intervals, receive an indication from the UE of an amount of data for transmission on the logical channel, and adjust the fixed first TB size of the periodically scheduled transmission resources to a fixed second TB size based on the indicated amount of data. In another aspect, a base station may configure a UE to enable scheduling request masking (SR-masking) on a logical channel, and configure the UE with a threshold amount of data for the logical channel to dynamically disable SR-masking on the logical channel. In another aspect, a UE may receive a configuration to enable scheduling request (SR) masking (SR-masking) on a logical channel, receive a configuration of a threshold amount of data for the logical channel to dynamically disable SR-masking on the logical channel, and decide whether to transmit an SR based on the amount of data to transmit and the threshold amount.