Improving Rural Emergency Services with Cognitive Radio Networks in Sub-Saharan Africa

International audienceIn this paper, we propose a new approach based on Cognitive Radio technology to address the challenges for ensuring connectivity in remote areas of Africa. Indeed, the current network coverage is concentrated around the cities with high density of population. Through the deployment of Cognitive Radio, emergency services in rural areas will benefit from low cost access networks. Cognitive Radio will be used to manage the selection/switching across different frequency UHF/VHF bands or TV White Spaces

Using AUTOSAR high-level specifications for the synthesis of security components in automotive systems

The increasing complexity and autonomy of modern automotive systems, together with the safety-sensitive nature of many vehicle information flows require a careful analysis of the security requirements and adequate mechanisms for ensuring integrity and confidentiality of data. This is especially true for (semi-)autonomous vehicle systems, in which user intervention is limited or absent, and information must be trusted. This paper provides a proposal for the representation of high-level security properties in the specification of application components according to the AUTOSAR standard (AUTomotive Open System ARchitecture). An automatic generation of security components from security-annotated AUTOSAR specifications is also proposed. It provides for the automatic selection of the adequate security mechanisms based on a high-level specification, thus avoiding complex and errorprone manual encodings by the designer. These concepts and tools are applied to a paradigmatic example in order to show their simplicity and efficacy

Interference Rejection Combining for Black-space Cognitive Radio Communications

This paper focuses on multi-antenna interference rejection combing (IRC) based black-space cognitive radio (BS-CR) operation. The idea of BS-CR is to transmit secondary user (SU) signal in the same frequency band with the primary user (PU) such that SU’s power spectral density is clearly below that of the PU, and no significant interference is inflicted on the PU receivers. We develop a novel blind IRC technique which allows such operation mode for effective reuse of the PU spectrum for relatively short-distance CR communication. We assume that both the PU system and the BS-CR use orthogonal frequency division multiplexing (OFDM) waveforms with common frame structure. In this case the PU interference on the BS-CR signal is strictly flat-fading at subcarrier level. Sample covariance matrix based IRC adaptation is applied during silent gaps in CR operation. During CR transmission, the target signal detection and channel estimation utilize multiple outputs from the IRC process obtained with linearly independent steering vectors. The performance of the proposed IRC scheme is tested considering terrestrial digital TV broadcasting (DVB-T) as the primary service. The resulting interference suppression capability is evaluated with different PU interference power levels, silent gap durations, and CR device mobilities.acceptedVersionPeer reviewe

Interpolation-Based Interference Rejection Combining for Black-Space Cognitive Radio in Time-Varying Channels

In this paper, we investigate multi-antenna interference rejection combing (IRC) based black-space cognitive radio (BS-CR) operation in time-varying channels. The idea of BS-CR is to transmit secondary user (SU) signal in the same frequency band with the primary user (PU) such that SU’s power spectral density is clearly below that of the PU, and no significant interference is inflicted on the PU receivers. We explore the effects of interpolation and mobility on the novel blind IRC technique which allows such operation mode for effective reuse of the PU spectrum for relatively short-distance CR communication. We assume that both the PU system and the BS-CR use orthogonal frequency division multiplexing (OFDM) waveforms with common numerology. In this case the PU interference on the BS-CR signal is strictly flat-fading at subcarrier level. Sample covariance matrix-based IRC adaptation is applied during silent gaps in CR operation. We propose an interpolation-based scheme for tracking the spatial covariance in time-varying channels, demonstrating significantly improved robustness compared to the earlier scheme. The performance of the proposed IRC scheme is tested considering terrestrial digital TV broadcasting (DVB-T) as the primary service. The resulting interference suppression capability is evaluated with different PU interference power levels, silent gap durations, data block lengths, and CR device mobilities.acceptedVersionPeer reviewe

Enhanced interpolation-based interference rejection combining for black-space cognitive radio in time-varying channels

In this paper, we investigate multi-antenna interference rejection combing (IRC)-based black-space cognitive radio (BS-CR) operation in time-varying channels. The idea of BS-CR is to transmit secondary user (SU) signal in the same frequency band with the primary user (PU) such that SU’s power spectral density is clearly below that of the PU, and no significant interference is inflicted on the PU receivers. We explore the effects of interpolation and mobility on the novel blind IRC technique which allows such operation mode for effective reuse of the PU spectrum for relatively short-distance CR communication. We assume that both the PU system and the BS-CR use orthogonal frequency division multiplexing (OFDM) waveforms with common numerology. In this case, the PU interference on the BS-CR signal is strictly flat-fading at subcarrier level. Sample covariance matrix-based IRC adaptation is applied during silent gaps in CR operation. We evaluate the effect of the gap length on the link performance, using known PU channel-based interference covariance estimation as reference. We also propose an interpolation-based scheme for tracking the spatial covariance in time-varying channels, demonstrating significantly improved robustness compared to the earlier scheme. The performance of the proposed IRC scheme is tested considering terrestrial digital TV broadcasting (DVB-T) as the primary service. Also joint PU and co-channel CR interference cancellation is included in the study. The resulting interference suppression capability is evaluated with different PU interference power levels, silent gap durations, data block lengths, and CR device mobilities.publishedVersionPeer reviewe