TDMA-based adaptive modulation with dynamic channel assignment for high-capacity communication systems

This paper proposes a time-division multiple-access (TDMA)-based adaptive m odulation scheme with dynamic channel assignment (AMDCA) to achieve high-ca pacity communication systems under dynamically changing propagation path an d traffic conditions. The proposed method measures the received carrier-to- noise plus interference power ratio (C/(N + I)) of each TDMA slot to search available slots as well as to find out the optimum modulation parameters f or each terminal, thereby effectively combining the effect of mitigating bo th spatially distributed electric field strength variation by the slow adap tive modulation and spatially and temporally distributed traffic variation by the dynamic channel assignment (DCA). Computer simulation confirms that the proposed AMDCA system can achieve app roximately three times higher system capacity than the conventional fixed c hannel assignment (FCA) using QPSK.