Symbol repetition and power re-allocation scheme for orthogonal code hopping multiplexing systems

We propose a symbol repetition and power re-allocation scheme to reduce a collision effect in orthogonal code hopping multiplexing (OCHM) systems. Each mapped symbol is repeated N times and an OCHM scheme is applied for downlink transmission. Through repetitions, the perforation effect is decentralized among the repeated symbols and the full perforation probability is significantly reduced. The transmit power is re-allocated among the repeated symbols to protect the symbols regardless of the number of perforations in the repeated symbols. Simulation results show that the proposed scheme saves the required energy by 4 dB in the independent Rayleigh fading channels for a frame error rate (FER) value of 1% when the perforation probability is 0.25.