main-content

## Über dieses Buch

This book constitutes the refereed proceedings of the 13th EAI International Conference on Cognitive Radio Oriented Wireless Networks, CROWNCOM 2018, held in Ghent, Belgium, in September 2018. The 20 revised full papers were selected from 26 submissions. The papers are organized thematically in tracks: Experimental, Licensed Shared Access and Dynamic Spectrum Access, and PHX and Sensing.

## Inhaltsverzeichnis

### Experimental Analysis of 5 GHz WiFi and UHF-TVWS Hybrid Wireless Mesh Network Back-Haul Links

Abstract
This paper reports on the experimental analysis of hybrid back-haul links comprising WiFi operating in the 5 GHz and Ultra High Frequency Television White Space bands. Possible link permutations are highlighted. Performance results show that overall network optimisation requires a combination of frequency division and time division duplexing.
Richard Maliwatu, Natasha Zlobinsky, Magdeline Lamola, Augustine Takyi, David L. Johnson, Melissa Densmore

### High-Level and Compact Design of Cross-Channel LTE DownLink Channel Encoder

Abstract
Field Programmable Gate Arrays (FPGAs) provide great flexibility and speed in Software Defined Radio (SDR). However, as a mobile wireless protocol, the LTE system needs to maintain coding procedures for different channels, and the hardware’s implementation is more complex than other wireless local area network (WLAN) specifications. Thus a compact and resource reusable LTE channel coder is needed as hardware resources and speed are the main pain points in SDR implementation. Traditional FPGA design and synthesis only focus on low levels of resource reuse, and IPs are independently designed without considering the whole system, which causes resource waste. In this paper, we describe a LTE downlink channel encoder processing chain implemented in FPGA hardware. Reuse in the whole system is done at a channel level and above, and scarce resources like BRAM are shared between processing units to maximize reuse. The system can efficiently process data and control channel signals at the same time using the same hardware. For the data channel, we use cross-component optimization to reduce the usage of BRAMs up to 25% for high volume data buffering. A novel rate matching design reduces the latency which improves the performance. By applying high-level reuse, the cross-component design can reduce resource usage while maintaining a good processing speed.
Jieming Xu, Miriam Leeser

### Detection of Different Wireless Protocols on an FPGA with the Same Analog/RF Front End

Abstract
The surge in smart phones, tablets, and other wireless electronics has drastically increased data usage and wireless communication, creating massive traffic spectrum demand. Congestion is mainly due to inefficient use of spectrum, rather than spectrum scarcity. Spectrum coexistence schemes provide opportunities for efficient use of the spectrum. Furthermore, software-defined hardware reconfiguration after signal detection can be completed to reduce the power consumption of adaptive analog/RF front ends. In this paper, we propose a Wi-Fi and LTE protocol coexistence architecture, and present its implementation using a Xilinx evaluation board and ADI RF front end.
Suranga Handagala, Mohamed Mohamed, Jieming Xu, Marvin Onabajo, Miriam Leeser

### Demonstration of Shared Spectrum Access of Different User Groups

Abstract
Spectrum availability is challenged everyday as the consumer consumption of mobile data increases. At the same time, the public safety and military authorities have the need to secure spectrum access for their mandated tasks that may vary temporally and spatially. Current spectrum administration and management schemes do not facilitate such short-term changes in time and space. In this paper, we show that minor adjustments to the Licensed Shared Access (LSA) scheme, and introduction of a spectrum manager function may provide administrations the tools to adjust spectrum assignments in time and space, so that they provide Mobile Network Operators sufficient security of spectrum access to justify investments, and that they allow authorities to access spectrum when their legally mandated tasks so require.
Topi Tuukkanen, Heikki Kokkinen, Seppo Yrjölä, Jaakko Ojaniemi, Arto Kivinen, Tero Jokela

### A Low-Latency Wireless Network for Cloud-Based Robot Control

Abstract
We demonstrate a reliable network for robot remote control in which a cross-layer PHY-MAC architecture is exploited to establish a low-latency and time-critical data transmission. In our demo, three reverse pendulum robots share the spectrum to communicate their sensory data to a processing unit which can instantly generate and transmit appropriate commands to maintain the robots’ balance.
To this end, we upgrade CLAWS (Cross-Layer Adaptable Wireless System) with a two-layer MAC platform which accelerates and facilities interrupt handling. To grant the network operational reliability, we elaborately coupled the FPGA-based IEEE 802.15.4 PHY in the CLAWS architecture with a set of hardware blocks that play the role of the low-level MAC. CLAWS also offers a run-time programmable module in which we deploy the high-level functionalities of the MAC protocol. Jointly with the implemented bi-layer MAC structure, we demonstrate how the CLAWS’ flexibility allows either standard compliant or ad-hoc network prototyping to establish a reliable cloud-based robot remote control.
Seyed Ali Hassani, Sofie Pollin

### Comparison of Incumbent User Privacy Preserving Technologies in Database Driven Dynamic Spectrum Access Systems

Abstract
Database driven dynamic spectrum sharing is one of the most promising dynamic spectrum access (DSA) solution to address the spectrum scarcity issue. In such a database driven DSA system, the centralized spectrum management infrastructure, called spectrum access system (SAS), makes its spectrum allocation decisions to secondary users (SUs) according to sensitive operational data of incumbent users (IUs). Since both SAS and SUs are not necessarily fully trusted, privacy protection against untrusted SAS and SUs become critical for IUs that have high operational privacy requirements. To address this problem, many IU privacy preserving solutions emerge recently. However, there is a lack of understanding and comparison of capability in protecting IU operational privacy under these existing approaches. In this paper, thus, we fill in the void by providing a comparative study that investigates existing solutions and explores several existing metrics to evaluate the strength of privacy protection. Moreover, we propose two general metrics to evaluate privacy preserving level and evaluate existing works with them.
He Li, Yaling Yang, Yanzhi Dou, Chang Lu, Doug Zabransky, Jung-Min (Jerry) Park

### Spectrum Leasing for Micro-operators Using Blockchain Networks

Abstract
This paper introduces a spectrum sharing system for Micro Operators (MOs) using the blockchain network. In order to satisfy different network requirements for each service, the license for spectrum access should be dynamically allocated to the required spectrum bandwidth. We propose a spectrum lease contract for MOs to share spectrum with the Mobile Network Operator (MNO) is performed through the blockchain networks. Main reasons for applying the blockchain network to the spectrum sharing system are as follow. First, the blockchain networks share database with all participants. Second, networks have mutual trust among all participants. Third, it needs no central authority. Fourth, automated contract execution and transaction interactions are possible. The blockchain usage in the MO-based spectrum sharing system and the detailed process of spectrum lease contract are proposed. Then, the economic effects of spectrum sharing system for MOs is analyzed. The MO can be profitable by getting involved in the blockchain to take reward for a Proof of Work (PoW) and providing wireless service to its users.
Junho Kim, Han Cha, Seong-Lyun Kim

### SZ-SAS: A Framework for Preserving Incumbent User Privacy in SAS-Based DSA Systems

Abstract
Dynamic Spectrum Access (DSA) is a promising solution to alleviate spectrum crowding. However, geolocation database-driven spectrum access system (SAS) presents privacy risks, as sensitive Incumbent User (IU) operation parameters are required to be stored by SAS in order to perform spectrum assignments properly. These sensitive operation parameters may potentially be compromised if SAS is the target of a cyber attack or SU inference attack. In this paper, we propose a novel privacy-preserving SAS-based DSA framework, Suspicion Zone SAS (SZ-SAS). This is the first framework which protects against both the scenario of inference attacks in an area with sparsely distributed IUs and the scenario of untrusted or compromised SAS. Evaluation results show SZ-SAS is capable of utilizing compatible obfuscation schemes to prevent the SU inference attack, while operating using only homomorphically encrypted IU operation parameters.
Douglas Zabransky, He Li, Chang Lu, Yaling Yang

### Secrecy Outage Probability of Cognitive Small-Cell Network with Unreliable Backhaul Connections

Abstract
In this paper, we investigate the secrecy performance of underlay cognitive small-cell radio network with unreliable backhaul connections. The secondary cognitive small-cell transmitters are connected to macro base station by wireless backhaul links. The small-cell network is sharing the same spectrum with the primary network ensuring that a desired outage probability constraint in the primary network is always satisfied. We propose an optimal transmitter selection (OTS) scheme for small-cell network to transfer information to the destination. The closed-form expression of secrecy outage probability are derived. Our result shows that increasing the primary transmitter’s transmit power and the number of small-cell transmitter can improve the system performance. The backhaul reliability of secondary and the desired outage probability of the primary also have significant impact on the system.
Jinghua Zhang, Chinmoy Kundu, Emi Garcia-Palacios

### Polarization-Space Based Interference Alignment for Cognitive Heterogeneous Cellular Network

Abstract
In underlay cognitive heterogeneous cellular network (CHCN), small cells can transmit their signals as long as the interference to macro cell is below a threshold. Consider a two-layer CHCN with polarized MIMO small cells, a novel polarization-space based interference alignment scheme is proposed. The cross-tier interference between macro cell and small cells is addressed by two given algorithms with different purposes. Orthogonal projection based polarization-space interference alignment (OP-PSIA) for ensuring the minimum effect to macro cell and interference constrained polarization-space interference alignment (IC-PSIA) for maximizing the performances of small cells if permitted. The co-tier interference between small cells are reduced by a minimum total mean squared error (MMSE) algorithm. Then we give specific solutions for two algorithms both including orthogonal projection processing and analytically iterative calculations. Simulation results show the improvement of two algorithms in BER performance of small cells while ensuring the protection of macro cell and keeping maximum overall sum rate.
Xiaofang Gao, Caili Guo, Shuo Chen

### The Vision of 5G and the Need for Change in Mobile Spectrum Access

Abstract
This paper discusses the need for change in the regulatory environment to cater for the next generation of mobile technology (5 G). It gives particular attention to provisioning of spectrum access for business specific services and applications and to possibilities to improve shared use of spectrum. It is proposed to broaden the market for mobile communication from a mobile operator specific market to a broadened market which is comprised of mobile operators, niche operators and service providers targeting specific business segments and private networks.
Peter Anker

### Coexistence of LTE Networks Under LSA Paradigm in 2.6 GHz Band

Abstract
This paper proposes a sharing scenario based on License Shared Access (LSA) framework with coexistence management between licensed Mobile Network Operator (MNO) and vertical MNOs. This allows the primary LSA license holder to lease the spectrum to the vertical operators when it is not used by the primary operator. We demonstrate the system in a real network consisting of two LTE-A base stations and core network, LSA Repository and LSA Controller. Furthermore, we implement the communication of the relevant network configuration parameters between the LSA Controllers in order to enable coexistence with interference-free conditions.
Jaakko Ojaniemi, Heikki Kokkinen, Arto Kivinen, Georgios Agapiou, Stamatis Perdikouris, August Hoxha, Adrian Kliks

Abstract
The interest in private LTE and private 5G radio licenses is increasing along the IMT frequency bands, higher frequencies, new spectrum assignments, and demand for wireless industrial communication. This paper studies the private LTE and 5G license pricing using Finland as an example. The methods for pricing are the actual block license-based frequency fee pricing, Administrative Incentive Pricing (AIP), device based Private Mobile Radio pricing, and the device-based pricing of the Netherlands. The study shows that the selection of the pricing mechanism greatly impacts the license prices. Spectrum policy and regulation can be the trigger for novel private network ecosystem creation through creation of simple authorization processes to reduce the cost and minimize the complexity of use of spectrum for private LTE. In particular, provision of clear rules and guidance for spectrum valuation and pricing for the national regulator itself, as well as for the stakeholders wanting to supply and operate private LTE was found essential in reducing the cost and minimizing the complexity of private LTE spectrum use.
Heikki Kokkinen, Seppo Yrjölä, Jan Engelberg, Topias Kokkinen

### LSA System Development with Sensing for Rapidly Deployable LTE Network

Abstract
Public safety users require radio spectrum for their communication systems. In this study, sensors are proposed as a backup spectrum information source in a rapidly deployed public safety long term evolution (LTE) communication network with licensed shared access (LSA) system. While the LSA system has been well developed, the drawback measures have not been thoroughly investigated from the application point of view. Herein, a collaborative sensing method is suggested for detecting an incumbent spectrum user and for establishing a protection zone around it. Furthermore, methods are developed for combining information from sensors and from an LSA system in a rapidly deployable public safety LTE network. The information from the sensors can be used for verifying incumbent protection and also for finding available spectrum in critical scenarios. The proposed methods give wider spectrum knowledge than just by using repository information or local sensor information.
Kalle Lähetkangas, Harri Posti, Harri Saarnisaari, Ari Hulkkonen

### Maxmin Strategy for a Dual Radar and Communication OFDM Waveforms System Facing Uncertainty About the Background Noise

Abstract
The paper considers the problem of designing the maxmin strategy for a dual-purpose communication and radar system that employs multicarrier OFDM style waveforms, but faces an uncertain level of background noise. As the payoff for the system, we consider the weighted sum of the communication throughput and the radar’s SINR. The problem is formulated as a zero-sum game between the system and a rival, which may be thought of as the environment or nature. Since the payoff for such a system combines different type of metrics (SINR and throughput), this makes underlying problem associated with jamming such a systems different from the typical jamming problem arising in communication scenarios, where the payoff usually involves only one of these metrics. In this paper, the existence and uniqueness of the equilibrium strategies are proven as well as water-filling equations to design the equilibrium are derived. Finally, using Nash product the optimal value of weights are found to optimize tradeoff of radar and communication objectives.
Andrey Garnaev, Wade Trappe, Athina Petropulu

### Using Deep Learning and Radio Virtualisation for Efficient Spectrum Sharing Among Coexisting Networks

Abstract
This work leverages recent advances in machine learning for radio environment monitoring with context awareness, and uses the obtained information for creating radio slices that can optimally coexist with ongoing traffic in a given spectrum band. We instantiate radio slices as virtualised radios built on a software-defined radio platform. Then, we describe a proof-of-concept experiment that validates and demonstrates our proposed solution.
Wei Liu, Joao F. Santos, Xianjun Jiao, Francisco Paisana, Luiz A. DaSilva, Ingrid Moerman

### Evaluating Deep Neural Networks to Classify Modulated and Coded Radio Signals

Abstract
Cognitive Radio (CR) systems allow optimizing the use of the shared radio spectrum and enhancing the coexistence among different technologies by efficiently changing certain operating parameters of the radios such as transmit-power, carrier frequency, and modulation and coding scheme in real-time. Dynamic Spectrum Access (DSA), which allows radios to dynamically access and use the unused spectrum, is one of the tasks that are fundamental for a better use of the spectrum. In this paper, we extend the previous work on Automatic Modulation Classification (AMC) by using Deep Neural Network (DNNs) and evaluate the performance of these architectures on signals that are not only modulated but are also encoded. We call this the Automatic Modulation and Coding Scheme Classification problem, or $$AMC^2$$. In this problem, radio signals are classified according to the Modulation and Coding Scheme (MCS) used during their transmission. Evaluations on a data set of 802.11 radio signals, transmitted with different MCS and Signal to Noise Ratio (SNR), provide important results on the impact of some DNN hyperparameters, e.g. number of layers, batch size, etc., in the classification accuracy.
Phui San Cheong, Miguel Camelo, Steven Latré

### Improving Spectrum Efficiency in Heterogeneous Networks Using Granular Identification

Abstract
Given the ever-increasing demand for wireless services and the pending explosion of the Internet of Things (IoT), demand for radio spectrum will only become more acute. Setting aside (but not ignoring) the need for additional allocations of spectrum, the existing spectrum needs to be used more efficiently so that it can meet the demand. Other than providing more spectrum there are other factors (like, transmit power, antenna angles, QoS, bandwidth, and others) that can be adjusted to cater to the demand and at the same time increase the spectrum efficiency. With heterogeneity and densification these factors are so varied it becomes necessary that we have some tool to monitor these factors so as to optimize our outcome. Here we propose a PHY layer granular identification that monitors the physical and logical parameters associated with a device/antenna. Through a simple optimization problem, we show how the proposed identification mechanism can further the cause of spectrum efficiency and ease coordination among devices in a heterogeneous network (HetNet) to assign resources more optimally. Compared to received signal strength (RSS) way of assigning resources the proposed approach shows a $$138\%$$ to $$220\%$$ increase (depending on the requested QoS) in spectrum efficiency. Ultimately, this research is aimed at assisting the regulators in addressing future spectrum related efficiency and enforcement issues.
Rohit Singh, Douglas Sicker

### Interference Rejection Combining for Black-Space Cognitive Radio Communications

Abstract
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.
Sudharsan Srinivasan, Markku Renfors

### An Image Processing Approach to Wideband Spectrum Sensing of Heterogeneous Signals

Abstract
We introduce a simple yet efficient framework for the localization and tracking of fixed-frequency and frequency-hopping (FH) wireless signals that coexist in a wide radio-frequency band. In this spectrum sensing scheme, an energy detector is applied to each Short-time Fourier Transform of the wideband signal to produce a binary spectrogram. Bounding boxes for narrowband signals are then identified by using image processing techniques on a block of the spectrogram at a time. These boxes are also tracked along the time axis and fused with the newly detected boxes to provide an on-line system for spectrum sensing. Fast and highly accurate detection is achieved in simulations for various FF signals and FH signals with different hopping patterns and speeds. In particular, for the SNR of 4 dB over a bandwidth of 50 MHz, 97.98% of narrowband signals were detected with average deviations of about $$0.02\,\mathrm{ms}$$ in time and $$2.15\,\mathrm{KHz}$$ in frequency.
Ha Q. Nguyen, Ha P. K. Nguyen, Binh T. Nguyen

### Backmatter

Weitere Informationen