Adaptive code-rate and modulation for multi-user OFDM system in wireless communications

Author

Moon, Jaekyoung ; Hong, Sangjin

Author_Institution

Dept. of Electr. & Comput. Eng., State Univ. of New York, Stony Brook, NY, USA

Volume

4

fYear

2002

fDate

2002

Firstpage

1943

Abstract

An adaptive code-rate and modulation allocation algorithm is considered for a multi-user OFDM system depending on transmission power and the transfer function of a frequency selective channel. The purpose of the presented adaptive code-rate and modulation OFDM system, using punctured convolutional code and various constellation sizes, is to maximize total capacity and to adapt the proper service for each user according to channel conditions and the transmit power, while maintaining the transmission´s quality of service (QoS) at the receiver. Computer simulation results show that the capacity of the adaptive code-rate and modulation OFDM system can be adaptively changed for various services. The performance of the system in a multipath fading channel with different delay spread is also analyzed.

Keywords

OFDM modulation; adaptive codes; adaptive modulation; convolutional codes; delays; fading channels; modulation coding; multipath channels; quality of service; variable rate codes; QoS; adaptive code-rate; delay spread; frequency selective channel; modulation; multipath fading; multiuser OFDM system; punctured convolutional code; quality of service; transmit power; variable bit rate transmission; Computer simulation; Convolutional codes; Delay; Fading; Modulation coding; OFDM modulation; Quality of service; Radio spectrum management; Transfer functions; Wireless communication;

fLanguage

English

Publisher

ieee

Conference_Titel

Vehicular Technology Conference, 2002. Proceedings. VTC 2002-Fall. 2002 IEEE 56th

ISSN

1090-3038

Print_ISBN

0-7803-7467-3

Type

conf

DOI

10.1109/VETECF.2002.1040557

Filename

1040557