Quantization-Aided Secrecy: FD C-RAN Communications with Untrusted Radios

Authors

O. Taghizadeh, T. Yang, H. Iimori, G. Abreu, A. C. Cirik, R. Mathar,

Abstract

In this work, we study a full-duplex (FD) cloudradio access network (C-RAN) from the aspects of infrastructuresharing and information secrecy, where the central unit utilizesFD remote radio units (RU)s belonging to the same operator,i.e., the trusted RUs, as well as the RUs belonging to otheroperators or private owners, i.e., the untrusted RUs. Furthermore,the communication takes place in the presence of untrustedexternal receivers, i.e., eavesdropper nodes. The communicateduplink (UL) and downlink (DL) waveforms are quantized inorder to comply with the limited capacity of the fronthaullinks. In order to provide information secrecy, we propose anovel utilization of the quantization noise shaping in the DL,such that it is simultaneously used to comply with the limitedcapacity of the fronthaul links, as well as to degrade decodingcapability of the individual eavesdropper and the untrustedRUs for both the UL and DL communications. In this regard,expressions describing the achievable secrecy rates are obtained.An optimization problem for jointly designing the DL and ULquantization and precoding strategies are then formulated, withthe purpose of maximizing the overall system weighted sumsecrecy rate. Due to the intractability of the formulated problem,an iterative solution is proposed, following the successive innerapproximation and semi-definite relaxation frameworks, withconvergence to a stationary point. Numerical evaluations indicatea promising gain of the proposed approaches for providinginformation secrecy against the untrusted infrastructure nodesand/or external eavesdroppers in the context of FD C-RANcommunications.

Keywords

privacy, quantization, infrastructuresharing, full-duplex, MIMO, C-RAN, physical layer security

BibT_EX Reference Entry

@article{TaYaIiAbCiMa22,
	author = {Omid Taghizadeh and Tianyu Yang and Hiroki Iimori and Giuseppe Abreu and Ali Cagatay Cirik and Rudolf Mathar},
	title = "Quantization-Aided Secrecy: FD C-RAN Communications with Untrusted Radios",
	pages = "1--15",
	journal = "{IEEE} Transactions on Wireless Communications",
	doi = 10.48550/arXiv.2107.08495,
	month = Unk,
	year = 2022,
	}

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