Licensed Shared Access System Research Articles

Editorial for Wiley's IJSCN Special Issue “Satellite networks integration with 5G”

Editorial for Wiley's IJSCN Special Issue “Satellite networks integration with 5G”

Spectral Efficiency of Dynamic Licensed Shared Access

In licensed shared access (LSA) the radio spectrum is dynamically shared between an incumbent and one or more licensee systems. Protective measures are applied to the licensees’ communication activity to protect the normal operation of the incumbent system. Such measures are therefore crucial components of the LSA, and thus fundamentally affect the achievable spectrum efficiency. In this paper, we investigate a vertical LSA including an airport traffic control system, as the incumbent, and a mobile network as the licensee. While some previous works only consider the licensee uplink, we analytically obtain the interference received by the incumbent from the licensee's transmission both in the uplink and downlink. We then obtain optimal uplink and downlink power allocation in the licensee using an optimisation problem with the objective of maximizing licensee's spectral efficiency (SE) subject to the incumbent interference threshold. Furthermore, we investigate the effect of the number of users and cell size on the SE. Our results provide quantitative insights for practical system design and deployment of LSA system. We then examine the whole LSA spectrum utilization by characterising the availability of the LSA spectrum using a tandem queue setting. Using this model we obtain an expression for the spectral utilization as a function of the licensee's achievable spectral efficiency and the statistics of the LSA spectrum availability. Simulation results show more than a seven-fold improvement in the licensee SE using the optimal power allocation. It is also seen that a higher SE gain is achieved with the proposed optimal power allocation in cases where the number of user equipment in the eNodeB coverage area is very small. Furthermore, higher spectrum utilization efficiency is achieved as a result of shorter busy period and higher achievable SE for distant cells.

Licensed shared access field trial and a testbed for satellite‐terrestrial communication including research directions for 5G and beyond

SummaryThis paper describes a licensed shared access (LSA) testbed and field trials using a live network. The testbed includes real 4G base stations and up to 1000 virtual base stations, in the spectrum sharing scenario between satellite and cellular systems. The trials focus on 5G pioneer bands 3.4–3.8 GHz and 24.25–27.5 GHz where a satellite system is operating in the downlink direction and a cellular system is accessing the same band. The designed testbed supports both frequency bands. The performance evaluation concerns evacuation and frequency change times using different types of base stations in 3.6 GHz, that is, how fast the system relinquishes the shared band to the primary user and continues transmission using another band. We show that our LSA system is scalable and able to support large number of base stations. In addition, we investigate how satellite systems could reuse International Mobile Telecommunication (IMT) bands to offer enhanced satellite communication services for land, maritime, and aeronautical applications. Preliminary simulations and analysis confirm the possibility to reuse IMT spectrum for satellite systems without causing harmful interference to the terrestrial system.

Fair Dynamic Spectrum Management in Licensed Shared Access Systems

Licensed shared access (LSA) is a spectrum sharing mechanism where bandwidth is shared between a primary network, called incumbent, and a secondary mobile network. In this paper, we address dynamic spectrum management mechanisms for LSA systems. We propose a fair spectrum management algorithm for distributing incumbent's available spectrum among mobile networks. Then, we adapt the proposed algorithm to take mobile network operator's regulatory compliance aspect into account and penalize the misbehaving network operators in spectrum allocation. We extend our results to the scenario where more than one incumbent offer spectrum to the mobile operators in a service area and propose various protocols, which ensure long term fair spectrum allocation within the individual LSA networks. Finally, we numerically evaluate the performance of the proposed spectrum allocation algorithms and compare them using various performance metrics. For the single incumbent case, the numerical results show that the spectrum allocation is fair when the mobile operators follow the spectrum access regulations. We demonstrate the effect of our proposed penalty functions on spectrum allocation when the operators do not comply with the regulatory aspects. For the multi-incumbent scenario, the results show a tradeoff between efficient spectrum allocation and flexibility in spectrum access for our proposed algorithms.

A Practical Perspective on 5G-Ready Highly Dynamic Spectrum Management with LSA

A diversity of wireless technologies will collaborate to support the fifth-generation (5G) communication networks with their demanding applications and services. Despite decisive progress in many enabling solutions, next-generation cellular deployments may still suffer from a glaring lack of bandwidth due to inefficient utilization of radio spectrum, which calls for immediate action. To this end, several capable frameworks have recently emerged to all help the mobile network operators (MNOs) leverage the abundant frequency bands that are utilized lightly by other incumbents. Along these lines, the recent Licensed Shared Access (LSA) regulatory framework allows for controlled sharing of spectrum between an incumbent and a licensee, such as the MNO, which coexist geographically. This powerful concept has been subject to several early technology demonstrations that confirm its implementation feasibility. However, the full potential of LSA-based spectrum management can only become available if it is empowered to operate dynamically and at high space-time-frequency granularity. Complementing the prior efforts, we in this work outline the functionality that is required by the LSA system to achieve the much needed flexible operation as well as report on the results of our respective live trial that employs a full-fledged commercial-grade cellular network deployment. Our practical results become instrumental to facilitate more dynamic bandwidth sharing and thus promise to advance on the degrees of spectrum utilization in future 5G systems without compromising the service quality of their users.

Unlocking the Deployment of Spectrum Sharing With a Policy Enforcement Framework

Spectrum sharing has been proposed as a promising way to increase the efficiency of spectrum usage by allowing incumbent operators (IOs) to share their allocated radio resources with licensee operators (LOs), under a set of agreed rules. The goal is to maximize a common utility, such as the sum rate throughput, while maintaining the level of service required by the IOs. However, this is only guaranteed under the assumption that all “players” respect the agreed sharing rules. In this paper, we propose a comprehensive framework for licensed shared access (LSA) networks that discourages LO misbehavior. Our framework is built around three core functions: misbehavior detection via the employment of a dedicated sensing network; a penalization function; and, a behavior-driven resource allocation. To the best of our knowledge, this is the first time that these components are combined for the monitoring/policing of the spectrum under the LSA framework. Moreover, a novel simulator for LSA is provided as an open access tool, serving the purpose of testing and validating our proposed techniques via a set of extensive system-level simulations in the context of mobile network operators, where IOs and several competing LOs are considered. The results demonstrate that violation of the agreed sharing rules can lead to a great loss of resources for the misbehaving LOs, the amount of which is controlled by the system. Finally, we promote that including a policy enforcement function as part of the spectrum sharing system can be beneficial for the LSA system, since it can guarantee compliance with the spectrum sharing rules and limit the short-term benefits arising from misbehavior.

Regulatory Pilot on Licensed Shared Access in a Live LTE-TDD Network in IMT Band 40

This paper presents the Italian pilot on licensed shared access (LSA) in the IMT Band 40 to explore the potential and logistics of spectrum sharing from a regulatory perspective. Organized on a small cell/micro cell scale, it verified both the technical feasibility and regulatory compliance of LSA in a real, LTE-TDD network, constrained by the national spectrum use in Band 40. The LSA system was implemented in compliance with the European Conference of Postal and Telecommunications Administrations, ETSI, and 3GPP specifications. We present an innovative distributed architecture implemented across three countries, enabling certain features of 5G networks. We describe the sharing framework and sharing conditions in the Italian scenario for the use cases representing actual incumbents. These were verified through in-field measurements, key results of which are presented. Measurement results show that sharing based on LSA is feasible to provide additional capacity for mobile broadband services in the 2300–2400 MHz band without detriment to incumbent services. Use of commercial off-the-shelf equipment to create new mobile broadband service in an urban indoor/outdoor environment pilot enabled us to assess the spectrum sharing opportunities through LSA technology for general deployment today and toward future policy for 5G spectrum in Italy.

Field Trial of Licensed Shared Access with Enhanced Spectrum Controller Power Control Algorithms and LTE Enablers

This paper presents the results from a field trial of the Licensed Shared Access (LSA) concept using TD-LTE network in the 3rd Generation Partnership Project spectrum band 40 (2.3–2.4 GHz) in Finland. In the field trial, the LTE network shared the spectrum with a program making and special events Incumbent. New LSA concept elements, LSA Repository for Incumbent protection information and LSA Controller for controlling the mobile broadband network in the same spectrum band were implemented in the trial environment. The trial utilized commercially available network elements like multimode multiband terminals, LTE base stations, core network and network management system. Incumbent spectrum usage data was collected to the LSA repository, which further converts it to spectrum availability information for the LSA controller. The trial goes beyond previous LSA demonstrations by presenting LSA controller power control concept algorithm that formulate the optimization objective as a function of base station cell transmit powers. An advantage of this procedure is that considering aggregated interference from the LTE network to Incumbent and adjusting the transmit power levels do not result in abrupt changes in the received signal quality and results better overall throughput. The developed LSA controller was implemented as self-organizing network solution integrated into network management system. Numerical results are presented to quantify the duration of the LSA procedure flow. The performance results on the LSA system workflow indicated that in the program, making special event use case the LSA band can be managed timely manner and the Incumbents’ rights can be protected.

ETSI-Standard Reconfigurable Mobile Device for Supporting the Licensed Shared Access

In order for a Mobile Device (MD) to support the Licensed Shared Access (LSA), the MD should be reconfigurable, meaning that the configuration of a MD must be adaptively changed in accordance with the communication standard adopted in a given LSA system. Based on the standard architecture for reconfigurable MD defined in Working Group (WG) 2 of the Technical Committee (TC) Reconfigurable Radio System (RRS) of the European Telecommunications Standards Institute (ETSI), this paper presents a procedure to transfer control signals among the software entities of a reconfigurable MD required for implementing the LSA. This paper also presents an implementation of a reconfigurable MD prototype that realizes the proposed procedure. The modem and Radio Frequency (RF) part of the prototype MD are implemented with the NVIDIA GeForce GTX Titan Graphic Processing Unit (GPU) and the Universal Software Radio Peripheral (USRP) N210, respectively. With a preset scenario that consists of five time slots from different signal environments, we demonstrate superb performance of the reconfigurable MD in comparison to the conventional nonreconfigurable MD in terms of the data receiving rate available in the LSA band at 2.3–2.4 GHz.