Hopfield multiuser detection of asynchronous MC-CDMA signals inmultipath fading channels

Multiuser reception using Hopfield neural network (HNN) for asynchronous multicarrier code-division multiple access (MC-CDMA) in a multipath fading channel is investigated. We have shown that by the appropriate choice of HNN parameters from the channel state information, the HNN can collectively resolve the multipath fading effects and the multiple-access interference in the system     

Multicarrier transmission using quadrature frequency/phasemodulation

Multicarrier (MC) systems using quadrature frequency and phase modulation (QFPM) schemes called MC-QFPM are described. In MC-QFPM systems, the power efficiency and resistance to delay spread can be increased for the price of reduced bandwidth efficiency. M-ary orthogonal frequency-shift-keying with M=1, 2 and 4 are considered along with MC modulation. The BER performance of MC-QFPM schemes in frequency selective delay spread environments is examined and compared     

Contents of Volume 18 (2003)

Neural Processing Letters -     

Successive interference cancelation for a CDMA system with diversity reception in non‐Gaussian noise

A large class of physical phenomenon observed in practical wireless systems exhibits non‐Gaussian behavior. The performance of many multiuser detectors can degrade substantially in the presence of such impulsive ambient noise. In this paper, multiuser detection of space coded MIMO and code division multiple access (CDMA) signals under impulsive noise with diversity reception are investigated. We analyze and derive the probability of bit error (P_b) performance of a successive interference cancelation (SIC) system under impulsive noise and maximal ratio combining. We use Middleton's class A model for the noise distribution. Furthermore, we employ post detection SIC as the robust multiuser detection technique for combating the impulsive noise at specific noise parameters in a CDMA setting. The performance of the system under power imbalance is also shown. Novel analytical derivations for both combining techniques are presented, and simulations were performed, which confirm the theoretical results. Copyright © 2011 John Wiley & Sons, Ltd.     

Multiuser Detection of Synchronous MC-CDMA in Multipath Fading Channels Using Hopfield Neural Networks

Sub-optimum multiuser reception using Hopfield Neural Network for synchronous Multicarrier Code-Division Multiple Access signals in a multipath fading channel is studied with respect to near-far ratio. We have shown that by the appropriate choice of Hopfield Neural Network parameters from the channel state information, the Hopfield network can collectively resolve the multipath fading effects and the multiple-access interference in the system. Moreover, the Hopfield Neural Network demonstrates multiple-access interference resilient performance regardless of the number of paths resolved at the receiver. We have also investigated the bit-error rate performance of the system with respect to channel estimation errors. Results show that performance of the proposed detection scheme is influenced by the correctness of the estimated channel state information.