Epilepsy patients experience challenges in daily life due to precautions they have to take in order to cope with this condition. When a seizure occurs, it might cause injuries or endanger the life of the patients or others, especially when they are using heavy machinery, e.g., deriving cars. Studies of epilepsy often rely on electroencephalogram (EEG) signals in order to analyze the behavior of the brain during seizures. Locating the seizure period in EEG recordings manually is difficult and time consuming; one often needs to skim through tens or even hundreds of hours of EEG recordings. Therefore, automatic detection of such an activity is of great importance. Another potential usage of EEG signal analysis is in the prediction of epileptic activities before they occur, as this will enable the patients (and caregivers) to take appropriate precautions. In this paper, we first present an overview of seizure detection and prediction problem and provide insights on the challenges in this area. Second, we cover some of the state-of-the-art seizure detection and prediction algorithms and provide comparison between these algorithms. Finally, we conclude with future research directions and open problems in this topic.

Precoding has emerged as a prominent technique to mitigate interbeam interference (IBI) in the forward link of a multibeam high throughput satellite system. In this paper, we consider zero-forcing (ZF) precoding to mitigate IBI. To reduce the channel state information (CSI) feedback from the user terminals, which consequently reduces the latency and signaling overheads, we design a ZF precoder with matrix and vector normalizations using partial CSI and analyze its ergodic SR performance. We consider a practical scenario where the links between the satellite and user terminals are affected by rain fading attenuation and derive an analytical expression, upper and lower bounds, and asymptotic (in terms of transmit power) approximations for the ergodic SR achieved by this ZF precoder. Many important insights are obtained from these results. Also, the robustness of this ZF precoder to CSI estimation errors is numerically analyzed.

In this paper, we present unified performance analysis framework of distributed transmit beamforming (DTB) with residual phase errors which arise from various sources such as imperfect synchronization and channel feedback quantization. More specifically, we derive statistics of the receive signal-to-noise ratio of DTB in Rayleigh and Rician fading channels in the presence of residual phase errors. In the case of residual phase errors caused by channel feedback quantization, we show that the distribution of residual phase errors can be modeled by uniform distribution in Rayleigh fading channels and Gaussian distribution in Rician fading channels. Also, our results reveal that a small number of bits are sufficient for quantized feedback to achieve comparable performance to DTB with perfect channel feedback. Finally, capitalizing on the derived statistics, we present closed-form expressions for the outage probability and the ergodic capacity of DTB with quantized channel feedback.

Next-generation multibeam high throughput satellite (HTS) systems aim at achieving Terabits/s throughputs with thousands of spot beams. Conventional radio frequency (RF) Ku-/Ka- band feeder links, between gateways and satellites, are unable to achieve such throughputs due to limited spectrum availability in these bands. Free space optical (FSO) feeder links present a promising alternative to RF feeder links and have gained increased attention lately in the satellite community. This article presents performance analysis of multibeam HTS systems where the feeder link operates in the FSO band and the user link, between the satellite and the user terminal, is in the RF Ka-band. We consider that the FSO feeder link is impaired by the scintillation fading due to atmospheric turbulence and the RF Ka-band user link is attenuated by the rain fading. In multibeam HTS systems, frequency reuse in the user link creates interbeam interference (IBI) due to overlapping side lobes of the multibeam antenna radiation pattern. Considering a forward link with a fixed gain transparent satellite payload, we use the zero-forcing precoding technique to mitigate IBI in the user link. We derive exact and approximate statistics of the end-to-end signal-to-interference-and-noise ratio. Also, by capitalizing on these results, we analyze information-theoretic metrics including the outage probability and ergodic capacity. Our results provide various important insights, e.g., 1) outage performance and ergodic capacity is typically restricted by rain fading in the RF link, and 2) outage diversity of rain fading in the RF link is 0, hence outage performance only increases marginally with power at high signal-to-noise ratio.

In this paper, we present the performance analysis of a multibeam high throughput satellite (HTS) system with optical feeder link. We consider the forward link, or downlink, with a fixed gain transparent satellite payload, where the optical feeder link, i.e. the link between gateway and satellite, is impaired by turbulence fading and the RF user link, i.e. the link between satellite and user terminals, is degraded by rain fading. In multibeam HTS systems, frequency re-use in the user link creates interbeam interference which needs to be mitigated to avoid performance degradation. For this purpose, we consider our recently proposed novel zero-forcing (ZF) precoder that does not require channel state information at the gateway and compare its performance with the conventional ZF precoder. We derive statistics of the end-to-end signal-to-noise ratio to approximate performance measures including outage probability, average bit error rate and ergodic capacity. These approximations provide valuable insights into the system analysis. Monte Carlo simulations are used to validate the accuracy of our analysis.

Spectrum sharing between heterogeneous systems - such as cellular systems, radars, and satellites - is an emerging area of research as it promises to solve the looming spectrum congestion problem. Spectrum regulators and technical specification bodies are contemplating over the idea of allowing commercial wireless systems to be deployed in satellite bands on a sharing basis. In the United States, the Federal Communications Commission (FCC) has proposed to deploy small cells in the 3.5 GHz satellite band. In this paper, we consider deployment of small cells in satellite bands and address opportunities and challenges that are associated with such a deployment. We focus on the conventional and extended C-band fixed satellite service (FSS) receiving earth stations. We show that small cell operation can result in out-of-band emission and low noise amplifier (LNA) saturation issues for FSS systems. Exclusion zones are required to protect FSS systems. We show that exclusion zones are quite larger when small cells are deployed outdoors as compared to the case when small cells are deployed indoors. Therefore, we propose that small cells should be deployed indoors for the scenarios where FSS systems are geographically colocated. This results in maximum utilization of small cell technology and minimum exclusion zones required to protect FSS receiving earth stations.