Optimal-Switching Adaptive Modulation for Multiuser Relay Networks with Feedback Delays

Adaptive Polarization Modulation in Depolarization Channel with Polarization Dependent Loss

“…In polarization modulation system, for a fixed target BER (BER tar ), SNR threshold γ j for constellation size M j are obtained from BER expressions. With regard to the BER expressions used to select the SNR thresholds, the existing adaptive MQAM schemes [7][8][9][10] employed the expressions for the BER of MQAM with Gray bit mapping in AWGN channel. Thus, in this paper, we also use the BER expressions of Morder polarization modulation in AWGN channel with Gray bit mapping, to determine SNR thresholds.…”

“…Thus, in this paper, we also use the BER expressions of Morder polarization modulation in AWGN channel with Gray bit mapping, to determine SNR thresholds. By comparing the estimated SNRγ with these thresholds γ j , the largest possible constellation size is selected [9]. So, in our adaptive system, the adaptive polarization modulation module at the transmitter adopts the optimal constellation size as follows…”

“…On the other hand, the application of adaptive modulation technique in OFDM systems, MIMO systems and relay networks has received a great deal of attention [7][8] [9]. [7] * This work is supported by Chinese National Nature Science Foundation (61271177), Fundamental Research Funds for the Central University under Grant No.…”

“…[8] presented variable-power adaptive modulation strategies with power control in time in MIMO systems, and it showed that the proposed method could obtain the same performance as other existing methods but with much lower computational complexity. [9] studied the performance of optimal switching adaptive modulation for multiuser amplifyand-forward relay networks and it indicated that adaptive modulation could be used as an effective remedy for practical transmission impairments such as feedback delays in these practical relay networks. For a brief overview of these papers, the adaptive QAM schemes are used and Rayleigh faded channel is considered.…”