• Journal of the Korean Institute of Telematics and Electronics
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• v.15 no.6
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• pp.29-34
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• 1978

It has been investigated that the elect of an wideband FDM-FM signal upon an M-ary coherent PSK (MCPSK) signal in an intersystem radio interference environment between analog and digital systems, which had not been discussed before and had been obscure. It is assumed that PSK and FM signal are adjacently allocated in same radio frequency band. And the symbol error performance of MCPSK signal with co-channel and adjacent channel interference from an FDM-FM signal is evaluated with considering the receiver noise. The numerical results for the theoretical symbol error rates of MCPSK system in the presence of Gaussian noise and co-channel or adjacent channel interference are given in graphical forms as the function of carrier-to-noise ratio (CNR), carrier-to-interference ratio (CIR) and normalized carrier separation between the desired PSK and interfering FM signal. The objective of this research is to find some optimal conditions for coexistence of analog and digital systems in an intersystem interference environment. The results we obtained here stress a possible utilization of them for designing the frequency allocation, bandwidth and power of PSK channel in the intersystem interference from an FDM-FM signall.

• Journal of Communications and Networks
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• v.8 no.3
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• pp.290-296
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• 2006

In this paper, a generalized blind adaptive algorithm is introduced for multi-user detection of direct sequence code division multiple access (OS-COMA) wireless communication systems. The main property of the proposed algorithm is its ability to resolve the multipath fading channel resulting in inter symbol interference (ISI) as well as multiple access interference (MAI). Other remarkable properties are its low complexity and mitigation to the near-far problem as well as its insensitivity to asynchronous transmission. The proposed system is based on the minimization of the output energy and convergence to the minimum mean square error (MMSE) detector. It is blind in the sense that it needs no knowledge of the other users' signatures, only the intended user signature and timing are required. Furthermore, the convergence of the minimum output energy (MOE) detector to the MMSE detector is analytically proven in case of M-ary PSK. Depicted results show that the performance of the generalized system dominates those previously considered. Further improvements are obtained when multiple input multiple output (MIMO) technique is employed.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.9C
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• pp.831-839
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• 2006

In this paper, we present an exact and general expression involving two-dimensional Gaussian Q-functions for the bit error rate (BER) of hierarchical MPSK with I/Q phase and amplitude imbalances over an additive white Gaussian noise (AWGN) channel. First we derive a BER expression for the k-th bit of hierarchical 4, 8, 16-PSK signal constellations when Gray code bit mapping is employed. Then, from the derived k-th bit BER expression, we present the exact and general average BER expression for hierarchical MPSK with I/Q phase and amplitude imbalances. This result can readily be applied to numerical evaluation for various cases of practical interest in an I/Q unbalanced hierarchical MPSK system, because the one- and two-dimensional Gaussian Q-functions can be easily and directly computed usinB commonly available mathematical software tools.