A mixed-cost blind adaptive receiver for DS-CDMA

A new mixed-cost receiver for direct-sequence code-division multiple access (DS-CDMA) systems is proposed. An adaptive mixing function is introduced to combine the constrained minimum output energy (CMOE) and constant modulus (CM) criteria together. Simulations confirm the near-far resistance of the proposed receiver over a wide range of near-far situation

A CMOE-CMA RAKE receiver structure for near-far frequency selective fading CDMA channels

A novel initialization scheme for a constant modulus algorithm RAKE (CMA-RAKE) receiver for frequency-selective fading asynchronous code-division multiple access (CDMA) channels is proposed. The solutions from the minimization of the constrained minimum output energy (CMOE) criterion are adopted as the initialization of the subsequent CMA receivers. The proposed receiver is proven to be near-far resistant at different levels of near-far problems. Simulations confirm the superiority of the receiver over the existing RAKE receivers in terms of signal-to-interference plus noise (SINR) ratio over a wide range of near-far situation

An adaptive step-size code-constrained minimum output energy receiver for nonstationary CDMA channels

The adaptive step-size (AS) code-constrained minimum output energy (CMOE) receiver for nonstationary code-division multiple access (CDMA) channels is proposed. The AS-CMOE algorithm adaptively varies the step-size in order to minimise the CMOE criterion. Admissibility of the proposed method is confirmed via the reformulation of the CMOE criterion as an unconstrained optimisation. The ability of the algorithm to track sudden changes of the channel structure in multipath fading channels is assessed. Sensitivity to the initial values of the step-size and the adaptation rate of the algorithm is also investigated

Convergence behaviours of an adaptive step-size constant modulus algorithm for DS-CDMA receivers

A convergence analysis of the blind adaptive step-size constant modulus algorithm (AS-CMA) for direct-sequence code division multiple access (DS-CDMA) receivers is presented. Analytical results show similar convergence behaviours of the AS-CMA receiver and the adaptive step-size stochastic approximation (ASSA) receiver. Simulations show that the blind AS-CMA algorithm performs comparably with the non-blind AS-SA in a Markovian type of nonstationary environment. The robustness of the proposed algorithm to different settings of the initial step-size is also shown