Differential Modulated Pilot Symbol Assisted Adaptive OFDM for Reducing the MLI with Predicted FBI

Chang-Jun AHN
Satoshi TAKAHASHI
Hiroshi HARADA

Publication
IEICE TRANSACTIONS on Communications   Vol.E88-B    No.2    pp.436-442
Publication Date: 2005/02/01
Online ISSN: 
DOI: 10.1093/ietcom/e88-b.2.436
Print ISSN: 0916-8516
Type of Manuscript: Special Section PAPER (Special Section on Multi-carrier Signal Processing Techniques for Next Generation Mobile Communications--Part2)
Category: 
Keyword: 
AMS/OFDM,  MLI,  FBI,  

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Summary: 
In an AMS/OFDM system, base station is in control of the modulation level of each subcarriers, and then, adaptive modulated packet is transmitted from the base station to the mobile station. In this case, the mobile station is required the modulation level information (MLI) to demodulate the received packet. The MLI is generally transmitted as a data symbol, therefore, the throughput is degraded. Moreover, it is necessary to have some transmission delay times and the processing time to make an adaptive modulation command (AMC) using feedback information (FBI). With the FBI delay and processing time, the system performance might be degraded. To reduce these problems, in this paper, we propose a differential modulated pilot symbol assisted adaptive OFDM for reducing the MLI with predicted FBI.