Adaptive modulation vs fixed modulation with deterministic interleaver

One of the prominent candidate of recent technology is OFDM-IDMA (Orthogonal Frequency Division Multiplexing Interleave Division Multiple Access). IDMA (Interleave Division Multiple Access) inherits most of the advantages of CDMA (Code Division Multiple Access). Adaptive Modulation improves the speediness of digital transmission over fading channels. The performance of system with adaptive modulation has shown a tremendous difference in the system without adaptive modulation. This paper deals with implementation of adaptive modulation with deterministic interleaver. The same performance is compared with the system having a fixed modulation scheme. Initially the fixed modulation schemes like PSK and QAM are implemented in OFDM IDMA system and their performance is studied. Later the performance of OFDM IDMA is enhanced with adaptive modulation. The obtained results show that a consequential amendments in terms of bit error rate (BER) and throughput can be achieved; demonstrating the preponderating of the adaptive modulation schemes compared to fine-tuned transmission schemes.