Preprocessing of TTI Bundling for Adaptive Transmission in LTE Uplink

In order to improve the cell coverage performance, transmission time interval (TTI) bundling technique is employed in long term evolution (LTE) uplink for the voice over internet protocol (VoIP) service. Recently, a coverage-enhanced scheme makes user equipment (UE) transmitting up to five bundles under the same delay budget. However, the coverage-enhanced scheme lacks time for feedback processing, in which the UE transmitting power may be wasted for an unnecessary retransmission. Taking the issue into account, we propose a scheme based on preprocessing of TTI bundling for adaptive transmission in LTE uplink. Our scheme uses block error rate (BLER) versus signal-to-noise ratio (SNR) mapping mechanism to reduce unnecessary retransmission bundles and save UE power consumption, yielding higher throughput.