Performance analysis of the window-based HARQ time bundling scheme

For LTE-A TDD systems supporting DL heavy asymmetry traffic, the number of downlink (DL) subframes are much higher than that of uplink (UL) subframes. The HARQ feedbacks of multiple DL tranport blocks may be transmitted in one UL subframe. Time-bundling is a technique proposed to reduce the HARQ signaling overhead by combining multiple ACK/NACKs into one using `AND' operation. In this paper, we propose a window-based HARQ time-bundling scheme to further enhance the legacy scheme. An analytical model is provided to analyze the performance of proposed scheme. We will show that the proposed scheme can reduce the signaling overhead and the analytical model can accurately estimate the performance of the proposed scheme.