Dynamic Sub-Carriers Allocation for OFDMA Systems Based on Effective SINR Measurements
Multi-carrier transmission techniques, based on Orthogonal Frequency Division Multiplexing (OFDM) and Orthogonal Frequency Division Multiple Access (OFDMA), guarantee a flexible and efficient use of the available spectrum in modern broadband 4G wireless access systems. In OFDM/OFDMA systems, the input data stream is divided into several parallel sub-streams of reduced data rate. Each sub-stream is modulated using QPSK, 16QAM or 64QAM formats and it is transmitted on one sub-carrier. In OFDMA/OFDM schemes, radio resources are partitioned into basic allocation units indicated in the following as slots.