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Quantum key distribution (QKD) enables provably secure communication between two parties over an optical fiber that arguably withstands any form of attack. Besides the need for a suitable physical signalling scheme and the corresponding devices, QKD also requires a secret key distillation protocol. This protocol and the involved signal processing handle the reliable key agreement process over the fragile quantum channel, as well as the necessary post-processing of key bits to avoid leakage of secret key information to an eavesdropper. In this paper we present in detail an implementation of a key distillation engine for a QKD system based on the coherent one-way (COW) protocol. The processing of key bits by the key distillation engine includes agreement on quantum bit detections (sifting), information reconciliation with forward error correction coding, parameter estimation, and privacy amplification over an authenticated channel. We detail the system architecture combining all these processing steps, and discuss the design trade-offs for each individual system module. We also assess the performance and efficiency of our key distillation implementation in terms of throughput, error correction capabilities, and resource utilization. On a single-FPGA (Xilinx Virtex-6 LX240T) platform, the system supports distilled key rates of up to 4 Mbps

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Abstract-A complete digital synchronization architecture for an IEEE 802.11ad compliant 60 GHz receiver is presented. The characteristics of mmWave systems require a holistic view on the problem of parameter estimation, such that not each parameter is dealt with on its own, but in the context of the complete receiver architecture. To this end the proposed synchronization unit covers packet detection, frequency offset compensation, signal-to-interference-plus-noise (SINR) maximization, frame synchronization, and channel estimation. The presented architecture is especially suitable for low-complexity time domain receivers, which are the most power efficient systems for mmWave, but have high demands in terms of synchronization. A novel two step synchronization procedure takes the specific requirements of the employed equalization and detection stages into account, to maximize the overall system performance. Performance is further improved by a heuristic sampling phase alignment mechanism which search the best sampling phase in order to increase the effective SINR in finite length receivers.

Abstract-The necessity of phase noise (PN) compensation in future 60 GHz communication systems is shown in this paper. Based on a reference hardware testbed we evaluate the impact of PN on the transmission performance. We show that long data transmissions can only be obtained with PN compensation even for low modulation orders. A low-complexity algorithm for phase noise estimation and compensation based on auto-correlation of pilot words is described. An efficient all-digital architecture for the proposed algorithm is presented.