Securing the Inter-Spacecraft Links: Doppler Frequency Shift based Physical Layer Key Generation

We propose a novel physical layer secret key generation method for the inter-spacecraft communication links. By exploiting the Doppler frequency shifts of the reciprocal spacecraft links as a unique secrecy source, spacecrafts aim to obtain identical secret keys from their individual observations. We obtain theoretical expressions for the key disagreement rate (KDR). Using generalized Gauss-Laguerre quadrature, we derive closed form expressions for the KDR. Through numerical studies, the tightness of the provided approximations are shown. Both the theoretical and numerical results demonstrate the validity and the practicality of the presented physical layer key generation procedure considering the security of the communication links of spacecrafts

Physical Layer Authentication for LEO Satellite Constellations

Physical layer authentication (PLA) is the process of claiming identity of a node based on its physical layer characteristics such as channel fading or hardware imperfections. In this work, we propose a novel PLA method for the inter-satellite communication links (ISLs) of the LEO satellites. In the proposed PLA method, multiple receiving satellites validate the identity of the transmitter by comparing the Doppler frequency measurements with the reference mobility information of the legitimate transmitter and then fuse their decision considering the selected decision rule. Analytical expressions are obtained for the spoofing detection probability and false alarm probability of the fusion methods. Numerically obtained high authentication performance results pave the way to a novel and easily integrable authentication mechanism for the LEO satellite networks

Space-frequency grouping based key extraction for MIMO-OFDM systems

International Symposium on Wireless Communication Systems (ISWCS); AUG 28-31, 2017; Bologna, ItalyLatest developments in wireless communication networks push the limits of conventional security methods. Security can be improved with a secret key that is dynamically generated based on the surrounding physical environment. With this objective, physical layer security approaches can be implemented by means of simple signal processing methods. In this paper, we propose novel key extraction approaches based on spatial and frequency characteristics of the wireless environment. In a 2x2 MIMO-OFDM system, low key disagreement rates and key error rates are observed, proving the potential of physical layer key extraction techniques

Key error rates in physical layer key generation: Theoretical analysis and measurement-based verification

Channel gains are frequently used to obtain a secret key that can be used for encryption in physical layer security systems. However, the channel gains captured by the nodes may not always be the same due to channel estimation errors. This would result in a non-zero key error rate (KER). In this letter, we obtain theoretical expressions for KER in orthogonal frequency division multiplexing systems. Tight KER approximations are provided based on Gauss-Laguerre quadrature. A measurementbased study is conducted by using software defined radio nodes to demonstrate the validity and the practicality of the provided results.TUBITAK (114E626

Optimal Joint Access Point Placement and Resource Allocation for Indoor mmWave Communications

In this paper, we formulate and solve the optimization problem for joint access point placement and resource allocation for indoor mmWave communications with static users, with a particular focus on airplanes. The proposed scheme obtains the required number of access points (APs) and their locations, for a given data rate threshold and given radio resources such as bandwidth, antenna numbers, and AP co-operation. We first build an airplane cabin environment in a ray-tracing tool to realistically capture the propagation effects. Then, we cast optimal deployment problems considering the performance of different AP cooperation schemes, namely coordinated scheduling (CS), non-coherent joint transmission (NC-JT), and coherent joint transmission (C-JT). The results indicate that full cooperation among the APs with C-JT requires fewer APs, especially under high data rate requirements. Comparing the network deployments in the mmWave and sub-6GHz bands, we observe 9 times higher data rates in mmWave although more APs are required.Part of ISBN 978-1-5386-7462-8QC 20231030</p