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Objective: The purpose of this study was to compare the originally applied frequency allocation of cochlear implant electrodes assigned by default at the time of activation with a more recent frequency allocation that is anatomy-based by a software called OTOPLAN®. Based on a computed tomography scan of the temporal bone, this software calculates the position of each electrode in the cochlea and its corresponding tonotopic frequency. We also evaluated whether patients with a significant mismatch between these two allocations present poorer speech intelligibility. Materials and Methods: Patients who underwent cochlear implantation from 2016 to 2021 at the University Hospital of Liege were included in this retrospective study. We used OTOPLAN® to calculate the tonotopic frequency allocation of each electrode according to its exact position in the cochlear duct. This anatomical frequency mapping was compared with the default frequency mapping at the time of cochlear implant activation. Finally, we compared the mismatch with the patients' auditory performance, represented by the Auditory Capacity Index (ACI). Results: Thirteen patients were included in the study. All patients had a mismatch between the two frequency maps, to a variable extent (200 Hz–1,100 Hz). Frequency shift was significantly inversely correlated with ACI and with the time needed to improve speech intelligibility. Conclusion: Our primary results show that patients with a larger mismatch between default frequency mapping and anatomically assigned frequency mapping experience poorer hearing performance and slower adaptation to a cochlear implant. [ABSTRACT FROM AUTHOR]

Smart cities rely on data, wireless technology, and connectivity; therefore, the radio spectrum is essential for their future development. This article provides an overview of the regulatory framework and relevant actors related to spectrum use, thereby promoting foreseeability and thus investment in the smart city ecosystem. The focus is the EU-level, but due to the importance of national and local levels, Finland functions as an example. The article highlights the important role of network slicing, infrastructure and spectrum sharing, other forms of cooperation for smart city development, and various operational models and alternatives. The article concludes that smart city operations are both possible and also supported by current regulation and allocation. Despite international and EU-level frameworks, national approaches remain relatively critical. Future real-life experiences will indicate the direction of spectrum regulation, but clearly smart cities require dynamic, local and flexible (use of) networks. [ABSTRACT FROM AUTHOR]

The increasing terrestrial and space-borne communications are causing major problems to the radio astronomy observations. Only a minor part of the frequencies is allocated to the passive services, such as Radio Astronomy Services (RAS). There are only a few, relatively narrow frequency bands below 20 GHz, which are still suitable for the radio astronomical observations. In addition, Out-of-Band (OoB) emissions will be a real threat to the observations on these bands. On behalf of all European radio astronomers, the Committee on Radio Astronomy Frequencies (CRAF) of the European Science Foundation (ESF) coordinates activities to keep the frequency bands used by radio astronomy and space sciences free of interference. Along with interference caused by active radio communication services, the local electronic device selection should be considered in the observatories. For instance, more common LED based lamps could cause harmful interference for the observations. Thus, it is very important to perform continuous radio frequency interference (RFI) monitoring locally, in each radio observatory. [ABSTRACT FROM AUTHOR]

Dynamic frequency allocation (DFA) with massive multiple-input multiple-output (MIMO) is a promising candidate for multicell communications where massive MIMO is adopted to maximize the per-cell capacity whereas the inter-cell interference (ICI) is tackled by DFA. Realizing this approach in a distributed fashion is however very difficult due to the lack of global channel state available at the base stations (BSs) in the cell level. We utilize a forward-looking game to automate reconciliation for DFA in a distributed manner between cells while zero-forcing (ZF) is used at each cell to maximize the multiplexing gain. To maximize the network capacity, multi-agent deep reinforcement learning (DRL) using offline centralized training is leveraged to train the BSs to master their game-theoretic reconciliation strategies. The result is a trained neural network for each BS, empowering it with rich experience of reconciliation with other BSs for converging to a network-efficient equilibrium. The online algorithm is distributed with the BSs competing as expert players to start the negotiation process using their trained actions. Simulation results show that the proposed synergized deep-learning game-theoretic algorithm outperforms significantly the DRL-only and game-theoretic only methods, and other benchmarks for multicell MIMO.

Mission-critical communications used worldwide for public safety have been based on narrow band solutions, framed in the different protocols included in Land Mobile Radio (LMR), such as APCO 25, used by the National Police. Although these technologies have been of great importance and have a fairly consolidated implementation maturity for reliable voice transmission, they have limitations for the transmission of data such as images and videos, making it necessary to take advantage of technology such as Long Term Evolution (LTE). In view of this need, it was carried out a technical scientific literature review, verifying the state of the art in several databases; likewise inclusion and exclusion criteria were determined for the study, thanks to which it was possible to identify that today there is no technological capacity to develope a LTE network for public safety; based on the above the need for a technological implementation that guarantees the coexistence of the two LMR and LTE neworks was identified, taking advantage of the benefits of each one of them in a sum that increases the technological capabilities in the police service. [ABSTRACT FROM AUTHOR]

Cellular networks are constantly evolving to ensure a better Quality of Service (QoS) and quality of coverage ever more important. The radio cellular systems are based on frequency allocation. In this context, frequency allocation principle consists in choosing an optimal frequency plan to meet traffic demand constraints and communication quality while minimizing the radio interferences. This paper proposes an optimal frequency allocation approach based on genetic algorithms to minimize co-channel and adjacent channel interference. The validation of this new approach is confirmed by the results of the work we have done in the GSM network. In fact, we used the file obtained by the OMC-R, which defines the adjacent cells of each cell and the frequencies allocated to the considered area. The results obtained clearly show the effectiveness and robustness of the approach used.

In this paper, we present the concept of the Radio Environment Map (REM) designed to ensure electromagnetic situational awareness of cognitive radio networks. The map construction techniques based on spatial statistics are presented. The results of field tests done for Ultra High Frequency (UHF) range with different numbers of sensors are shown. Exemplary maps with selected interpolation techniques are presented. Control points where the signal from licensed users is correctly estimated are identified. Finally, the map quality is assessed, and the most promising interpolation techniques are selected. [ABSTRACT FROM AUTHOR]

In this paper, a novel 3D cellular model consisting of aerial base stations (aBSs) and aerial user equipments (aUEs) is proposed, by integrating the coordinated multi-point (CoMP) transmission technique with the theory of stochastic geometry. For this new 3D architecture, a tractable model for aBSs’ deployment based on the binomial-Delaunay tetrahedralization is developed, which ensures seamless coverage for a given space. In addition, a versatile and practical frequency allocation scheme is designed to eliminate the inter-cell interference effectively. Based on this model, performance metrics including the achievable data rate and coverage probability are derived for two types of aUEs: i) the general aUE (i.e., an aUE having distinct distances from its serving aBSs) and ii) the worst-case aUE (i.e., an aUE having equal distances from its serving aBSs). Simulation and numerical results demonstrate that the proposed approach emphatically outperforms the conventional binomial-Voronoi tessellation without CoMP. Insightfully, it provides a similar performance to the binomial-Voronoi tessellation which utilizes the conventional CoMP scheme; yet, introducing a considerably reduced computational complexity and backhaul/ signaling overhead. [ABSTRACT FROM AUTHOR]

In the heterogeneous networks (HetNets), the downlink-uplink decoupled (DUDE) user association is a very promising technology that can employ different association strategies for uplink and downlink. The DUDE mode has great potential for improving system capacity and frequency efficiency. However, interference between the DUDE user equipment (DUDE UE), macro user equipment (MUE) and small user equipment (SUE) still needs to be considered and properly tackled. Therefore, this paper presents an optimization scheme of frequency allocation and power control to improve the communication quality of users. Firstly, the multiple region frequency allocation (MRFA) scheme is proposed for non-uniform user distribution to alleviate interference among users and allocate spectrum resources equally to dense users. This scheme is modelled as a sub-region partition problem with maximum sum rate, which can disperse densely distributed users to different sub-bands for transmission. Secondly, the convergent power control (CPC) algorithm is considered to improve the transmission performance of each user. It can converge the transmit power to the optimal transmit power for reducing interference among co-channel users when there is no disturbance in the network. The CPC algorithm can also make the signal-to-interference-plus-noise-ratio (SINR) of each active user always greater than the target threshold until the end of communication by dynamically adjusting the transmit power of users. Simulation results show that the joint scheme of MRFA and CPC achieves a higher system throughput and better user performance than existing frequency allocation schemes or power control schemes. [ABSTRACT FROM AUTHOR]

Cellular networks are constantly evolving to ensure a better Quality of Service (QoS) and quality of coverage ever more important. The radio cellular systems are based on frequency allocation. In this context, frequency allocation principle consists in choosing an optimal frequency plan to meet traffic demand constraints and communication quality while minimizing the radio interferences. This paper proposes an optimal frequency allocation approach based on genetic algorithms to minimize co-channel and adjacent channel interference. The validation of this new approach is confirmed by the results of the work we have done in the GSM network. In fact, we used the file obtained by the OMC-R, which defines the adjacent cells of each cell and the frequencies allocated to the considered area. The results obtained clearly show the effectiveness and robustness of the approach used. [ABSTRACT FROM AUTHOR]

In this paper we model a situation where several wireless body sensor networks (WBSN) compete for occupation of a number of frequency channels. Each channel can host at most one WBSN with satisfactory performance and WBSNs have the ability to change their operating channel, subject to the constraint that they can only monitor the performance or occupancy of their current channel but not of any other channel. We consider a number of randomized schemes for changing the frequency channels and present and evaluate Markov chain models for these, building on a "balls-in-bins" approach. [ABSTRACT FROM AUTHOR]

Frequency allocation problem is considered an NP problem which requires a large search space to find the optimal solution. This paper presents a hybrid algorithm between the Hopfield neural network and the tabu search techniques algorithm to allocate frequencies in the cells of cellular network. The cellular telephone system is composed of small regions called cells, it's depends on the principles of frequencies reuse due to the limited number of frequencies. As a result to this reuse the problem of frequency allocation is a raised. Simply it can be defined as the allocation of different frequencies to each cell and it’s neighbouring. In this hybridization the principles of short term memory and candidate list in tabu search are embedded in Hopfield neural network to control the operation of neuron selection.

Objective: The purpose of this study was to compare the originally applied frequency allocation of cochlear implant electrodes assigned by default at the time of activation with a more recent frequency allocation that is anatomy-based by a software called OTOPLAN®. Based on a computed tomography scan of the temporal bone, this software calculates the position of each electrode in the cochlea and its corresponding tonotopic frequency. We also evaluated whether patients with a significant mismatch between these two allocations present poorer speech intelligibility., Materials and Methods: Patients who underwent cochlear implantation from 2016 to 2021 at the University Hospital of Liege were included in this retrospective study. We used OTOPLAN® to calculate the tonotopic frequency allocation of each electrode according to its exact position in the cochlear duct. This anatomical frequency mapping was compared with the default frequency mapping at the time of cochlear implant activation. Finally, we compared the mismatch with the patients' auditory performance, represented by the Auditory Capacity Index (ACI)., Results: Thirteen patients were included in the study. All patients had a mismatch between the two frequency maps, to a variable extent (200 Hz-1,100 Hz). Frequency shift was significantly inversely correlated with ACI and with the time needed to improve speech intelligibility., Conclusion: Our primary results show that patients with a larger mismatch between default frequency mapping and anatomically assigned frequency mapping experience poorer hearing performance and slower adaptation to a cochlear implant., (© 2024 S. Karger AG, Basel.)

In this paper, we present the concept of the Radio Environment Map (REM) designed to ensure electromagnetic situational awareness of cognitive radio networks. The map construction techniques based on spatial statistics are presented. The results of field tests done for Ultra High Frequency (UHF) range with different numbers of sensors are shown. Exemplary maps with selected interpolation techniques are presented. Control points where the signal from licensed users is correctly estimated are identified. Finally, the map quality is assessed, and the most promising interpolation techniques are selected.

Recently, mobile communication providers have begun to rollout nationwide 5G services in Japan. In addition to these services, the MIC(Ministry of Internal Affairs and Communications) of Japan has reviewed and introduced the basic concepts of a local 5G service, frequency allocation, basic policy direction, and technical regulations for licensing, which can be flexibly constructed and used by various entities, according to the needs of local services and various industries. At present, the introduction of a local 5G system is under review in Korea, in response to industry demands. Therefore, in this paper, we propose a persuasive policy for planning the introduction of a 5G system in Korea by analyzing the local 5G policy directions in Japan and Germany. [ABSTRACT FROM AUTHOR]

Recent developments regarding media services transmitted through broadcasting and broadband technology have sparked new trends in digitalization and media convergence. Digitalization was supposed to safeguard the key social role of broadcasting in Europe, but it has mainly intensified its market dependence and orientation. Broadcasters no longer have priority in spectrum policy over online audio-visual services and broadband. Against this background, we analyse how much broadcasting is losing ground as a privileged cultural form as well as a widely used form of electronic mass communication technology in Austria. Through document analysis and stakeholder interviews, this article addresses how far, between 2007 and 2017, regulation, frequency allocations and the preferences of politicians and key stakeholders point at the substitution of broadcasting by broadband as the main means for the provision of media mass communication. The project draws on a new-institutionalist approach, which states that the output in a given policy process can be understood by researching technological change and the preferences of state and market actors together with the ideological cleavages and the formal and informal institutional rules affecting the process. The research objectives are: (1) to assess the evolution of media policy and communication legislation affecting broadcasting and electronic communication during the final stage of TV digitalization in Austria; (2) to assess the available supply and demand of the radio spectrum for free-to-air (FTA) broadcasting and the frequency share of broadcasters and (mobile) broadband operators; (3) to assess the understanding that political decision-makers and key stakeholders have regarding the role of broadcasting and broadband services both as social practice and as a technological solution for mass communication. The findings, which generally point to a shift from broadcast to broadband, are analysed against the background of the WRC 2015 outcome. [ABSTRACT FROM AUTHOR]

Co-channel interference (CCI) degrades performance of cellular networks. Therefore, this paper addresses CCI problem in relay-assisted (R-A) orthogonal frequency division multiple access cellular systems. Analytical treatments are conducted. The network performance improvements through reducing CCI effects are evaluated using different four interference mitigation models. These models represent R-A strict fractional frequency reuse (FFR) technique with frequency reuse factor (FRF) = 3, R-A strict FFR technique with FRF = 4, R-A sectored FFR technique and R-A soft frequency reuse (SFR) technique. Each model contains two different configurations for further network performance improvement. The first configuration assumes three relay stations (RSs) per cell (RPC) while the other one proposes 6 RPC. The best RSs locations in terms of SIR are proposed. Moreover, closed-form expressions for worst cases CEU's SIR, cell centre user's SIR and inner radius are implemented. These expressions are used to compare different models using various performance evaluation metrics. The results demonstrate that the two configurations in R-A sectored FFR and R-A strict FFR models provide equal CEU's SIR. The reason of this result can be attributed to applying equal power transmission strategy. Moreover, the two configurations of R-A SFR network attain different CEU's SIR values. This result can be accredited to the SFR power control factor. The work outcomes attain much higher CEU's SIR improvement. Therefore, the outage probability is decreased. Thus, more users can be covered by the network. Accordingly, the total network cost is reduced. So, this treatment improves the network performance while keeping lower network cost. [ABSTRACT FROM AUTHOR]

Wireless Communication technologies are growing rapidly to meet increasing demands of users. This creates overhead in existing wireless systems. This manifests in the continuous development of wireless systems to keep pace with the increasing capacity demand. Increase in the number of users increases congestion in cellular bands, hence Extremely High Frequency (EHF) bands such as mmWave are attracting growing attention for use in cellular networks. Millimeter Wave (mmWave) bands can support multi‐Gigabit rates for large bandwidth applications in Next generation networks. These bands have certain limitations like, these cannot travel long distances and cannot penetrate buildings and other objects. These limitations can be advantageously exploited to provide more secure communication and permit high‐frequency reuse. This will facilitate efficient spectrum utilization and support design of densely packed networks. This paper reviews the propagation characteristics of mmWaves and effect of external factors like atmospheric gases, rain, foliage, and diffraction. Our main focus will be to study the effect of these factors on the propagation of mmWave frequencies to be used for 5G cellular networks. We evaluate the losses due to atmospheric gases, rain and foliage at 28, 30 and 60 GHz frequencies which are supposed to be used in 5G cellular networks. [ABSTRACT FROM AUTHOR]

The rapid evolution of network services demands new paradigms for studying and designing networks. We propose a framework to investigate the underlying mechanisms of wireless network functions. This framework isolates and analyses a network function as a complex system. We propose functional topologies to visualize and systematically study the relationships between system entities. We also define a complexity metric CF (functional complexity), which quantifies the variety of structural patterns and roles of nodes in the topology. This complexity metric provides a wholly new approach to study the operation of telecommunication networks. We study the relationship between CF and graph structures by analysing graph theory metrics in order to recognize complex organizations. CF is equal to zero for both a full mesh topology and disconnected topology. We show that complexity is high for a structure with shorter average path length and higher average clustering coefficient. We make a connection between functional complexity, robustness and response to changes that may appear in the system configuration. We also make a connection between the implementation and the outcome of a network function, which correlates the characteristics of the outcome with the complex relationships that underpin the functional structure. [ABSTRACT FROM AUTHOR]