Adaptive Power Allocation for Distortion Minimization in Generalized Polar Optical Wireless Communications

Guo, Shuaishuai; Park, Kihong; Alouini, Mohamed-Slim

Adaptive Power Allocation for Distortion Minimization in Generalized Polar Optical Wireless Communications

Type

Article

Authors

Guo, Shuaishuai

Park, Kihong

Alouini, Mohamed-Slim

KAUST Department

Communication Theory Lab
Computer, Electrical and Mathematical Sciences and Engineering (CEMSE) Division
Electrical Engineering Program

Online Publication Date

2019-09-03

Print Publication Date

2019-12

Date

2019-09-03

Abstract

In this paper, we investigate adaptive power allocation for generalized polar optical wireless communications (OWC), where a general complex bipolar signal is converted into magnitude and phase signals for intensity modulation. Mean square errors (MSE) between the input complex signals and the re-constructed complex signals are derived to characterize signal distortion. Optimal power scaling factors and power allocation are investigated to minimize the distortion. Under a sole average intensity constraint, closed-form optimal power scaling factors are derived and found to be input-dependent. Specifically, they are determined by the first and second moments of the magnitude signals, the first moment of the phase signals as well as the channel state. Under both average and peak intensity constraints, the expression of MSE regarding the power scaling factors is derived but it is too complicated to find the optimal power allocation. Thus, we propose to use a small-scale numerical search for practical power allocation. As an example, we adopt the proposed power allocation to polar optical orthogonal frequency division multiplexing (P-OFDM) systems and analyze its achievable bit error rate (BER). Numerical simulations are presented to validate the analysis. It is shown that the proposed power allocation greatly improves the performance in terms of MSE and BER and the proposed power allocation-enhanced P-OFDM (EP-OFDM) outperforms existing optical OFDM schemes over various channels in the high signal-to-noise ratio (SNR) regime, especially in the systems with a peak intensity constraint.

Citation

Guo, S., Park, K.-H., & Alouini, M.-S. (2019). Adaptive Power Allocation for Distortion Minimization in Generalized Polar Optical Wireless Communications. IEEE Transactions on Communications, 67(12), 8545–8556. doi:10.1109/tcomm.2019.2938749

Acknowledgements

The work of K.-H. Park and M.-S. Alouini was supported by the funding from KAUST.