A New Look at Dual-Hop Relaying: Performance Limits with Hardware Impairments
Journal article, 2013

Physical transceivers have hardware impairments that create distortions which degrade the performance of communication systems. The vast majority of technical contributions in the area of relaying neglect hardware impairments and, thus, assume ideal hardware. Such approximations make sense in low-rate systems, but can lead to very misleading results when analyzing future high-rate systems. This paper quantifies the impact of hardware impairments on dual-hop relaying, for both amplify-and-forward and decode-and-forward protocols. The outage probability (OP) in these practical scenarios is a function of the effective end-to-end signal-to-noise-and-distortion ratio (SNDR). This paper derives new closed-form expressions for the exact and asymptotic OPs, accounting for hardware impairments at the source, relay, and destination. A similar analysis for the ergodic capacity is also pursued, resulting in new upper bounds. We assume that both hops are subject to independent but non-identically distributed Nakagami-m fading. This paper validates that the performance loss is small at low rates, but otherwise can be very substantial. In particular, it is proved that for high signal-to-noise ratio (SNR), the end-to-end SNDR converges to a deterministic constant, coined the SNDR ceiling, which is inversely proportional to the level of impairments. This stands in contrast to the ideal hardware case in which the end-to-end SNDR grows without bound in the high-SNR regime. Finally, we provide fundamental design guidelines for selecting hardware that satisfies the requirements of a practical relaying system.

Amplify-and-forward

dual-hop relaying

BOUNDS

COOPERATIVE

Nakagami-m fading

TRANSCEIVER IMPAIRMENTS

DIVERSITY

transceiver hardware impairments

outage probability

RAYLEIGH FADING CHANNELS

ergodic capacity

ERGODIC CAPACITY

decode-and-forward

TRANSMISSIONS

ALLOCATION

SYSTEMS

Author

E. Bjornson

SUPELEC Campus de Gif

Royal Institute of Technology (KTH)

Michail Matthaiou

Chalmers, Signals and Systems, Signal Processing and Biomedical Engineering

M. Debbah

SUPELEC Campus de Gif

IEEE Transactions on Communications

0090-6778 (ISSN) 15580857 (eISSN)

Vol. 61 11 4512-4525 6630485

Subject Categories

Telecommunications

DOI

10.1109/tcomm.2013.100913.130282

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4/5/2022 6