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Modeling and Optimization of Interference Limited Wireless Communications
Author(s) -
Irmer Ralf,
Fischer Andreas
Publication year - 2004
Publication title -
pamm
Language(s) - English
Resource type - Journals
ISSN - 1617-7061
DOI - 10.1002/pamm.200410286
Subject(s) - computer science , optimization problem , transmitter , sequential quadratic programming , code division multiple access , wireless , nonlinear programming , transmitter power output , mathematical optimization , interference (communication) , channel (broadcasting) , transmission (telecommunications) , nonlinear system , quadratic programming , computer network , algorithm , telecommunications , mathematics , physics , quantum mechanics
Multiple access interference (MAI) limits the system capacity of wireless communications systems applying code division multiple access (CDMA). Provided that channel knowledge is available in the transmitter, the transmitted signal can be preprocessed by multiuser transmission (MUT) methods. As optimization criterion, the bit error probability/rate (BER) is chosen. On the transmit signal, a limited power constraint is imposed, which is a quadratic function of the transmit signal. The nonlinear optimization problem is modeled in this paper. Unfortunately, the problem is non‐convex. However, with iterative nonlinear optimization methods like SQP, local minima can be found with a performance outperforming other MUT methods. The main remaining challenge are low‐complexity optimization algorithms to allow for a real‐time implementation in highdata rate wireless communications. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)