Short-term spectrum sharing with economic awareness in 5G networks

University of Technology Sydney. Faculty of Engineering and Information Technology.The next Generation Mobile Networks 5G is expected to start rolling out by 2020, targeting at significantly faster mobile data speeds and increasingly massive machine communications. As we are entering into a whole new wireless time, where the blend of spectrum policy and technology becomes more important, the networking practices are tightly coupled with economic considerations. Therefore, a novel economic-driven spectrum policy should be designed to support all spectrum access methods with flexibility to take advantage of potentially new spectrum sharing paradigms. In this thesis, we present the feasibility of putting economic models in the existing dynamic spectrum sharing architectures, from three aspects: spectrum sublicensing at a small scale, spectrum auction design, and licensed and unlicensed band selection. We point out the challenges under each scenario and propose solutions to address these problems. First, for the spectrum sublicensing, we introduce the concept of the protection zone to enable multiple operators to spatially share the spectrum and ensure exclusive usage without any interference. Furthermore, the trade-off between the precision of boundary estimation and the cost of sensing networks is analysed. Second, for the spectrum auction, we study how an interference graph influences performance of the auction algorithm and guarantees fairness and truthfulness. Additionally, we further propose a negotiable auction for a more efficient spectrum allocation based on a mixed graph which offers a base station a second chance if the original request is rejected. Unlike the existing work, our proposed solution with a faster grouping scheme performs better in a dense situation, hence it accommodates more base stations. Third, for the licensed and unlicensed band selection from the perspective of operators, we build a finite game and present performance comparisons of different strategies. Moreover, the analysis of the Nash equilibrium is provided and so are the suggestions on how to achieve high benefits for different scales of operators. We apply our design and findings to the potential spectrum sharing architectures, i.e., Licensed Shared Access and Spectrum Sharing System. We strengthen the coupling of the sublicensing scheme with the spectrum sharing platforms by enabling each base station as an individual bidder and let them bid for a contour based sublicense, ensuring the exclusive right and interference protection. Additionally, we also analyse the unlicensed and licensed band selection from the perspective of operators and prove the equilibrium existence in the spectrum market. In conclusion, the short-term sublicensing in the secondary market has not been fully studied and put into practice yet. The thesis has given rise to an integration of spectrum technology and policy. It is believed that, in the future, the economic-aware spectrum policy design could be incorporated into communication technology to realize an innovative, efficient and flexible sharing model

Fostering Collaboration in Emerging Three-Tiered Spectrum Markets

Ensuring optimum spectral efficiency is a critical requirement for current wireless networks to cope with the ever-growing flow of wireless data traffic, using limited spectral resources. As such, spectrum sharing, which allows different grades of users, as well as multiple networking standards to co-exist and utilize in the same frequency band, has become a topic of great intrigue. Due to the inherent advantages of these schemes, the US government has opened up vast amounts of federal spectrum that supports spectrum sharing. The Citizens Broadband Radio Service (CBRS) proposed by the Federal Communications Commission (FCC) is one of them. A tiered spectrum sharing approach, CBRS allows end commercial users to share the radio spectrum with federal incumbent users in the 3,550-3,700 MHz range. Employing a light leasing approach, the FCC aims to encourage the licensed providers of CBRS called the Priority Access License (PAL), to lease/share their licensed spectrum with unlicensed users named the General Authorized Access (GAA) for limited duration, which is essential for the maximum utilization of the CBRS bandwidth, but the current approach proves ineffective for that purpose. In this thesis, we propose a novel clustered framework to facilitate this sharing, where GAA users are grouped into multiple distinct geographical clusters and request access to licensed spectrum through the clusters in a collaborative manner rather than individually. Each cluster will nominate a central entity denoted as the GAA leader to communicate their requests to the PAL operators, as well as establish temporary connections with PAL access points once granted permission for licensed CBRS access, to be used by GAAs outside the operators coverage range. The leaders will also receive information from the PAL operators regarding the number of requests they are willing to accept and transmit that to the GAAs within the cluster. This process reduces the amount of information flow between the licensed and unlicensed entities, thereby providing a convenient platform for CBRS spectrum sharing. In order to determine the leader, the role of which can be assumed by any of the GAA users within the cluster, we formulate a distributed leader selection algorithm algorithm called the LSA, which takes into account the signal strength of the PAL access points available the GAA users, as well as the network density of each GAA node, to assign a score called the leader evaluation score (LES) to each GAA user and nominate the user with the highest score as the leader. To encourage PAL operators to frequently share their licensed spectrum, we incorporate a government reward model, where operators are incentivized by gaining access to additional spectrum for limited periods based on their level of sharing

Game theoretic analysis of sublicensing for PAL and GAA bands in spectrum access system

© 2017 IEEE. Motivated by recent efforts in enabling economic models for spectrum sharing systems, in particular, for the Spectrum Access System in the US, we propose a game theoretic analysis of sublicensing between two types of access methods in such system - PAL and GAA. The aim of this paper is to illustrate how the operators' strategies affect their own payoffs and the overall utility in the Sublicenseing Game in a spectrum sharing system. We consider the problem of spectrum sharing among multiple operators who have to pay for a temporary PAL sublicense with the exclusive right to the PAL band or stay in the GAA band and share the spectrum for free with other GAA users. We first formulate this scenario as a non-cooperative game, and then study the existence of a Nash equilibrium. Finally, to reduce the overall utility loss we let the spectrum sharing platform to coordinate individual operators by forming pair coalitions for them. According to our findings, when an operator has a large number of subscribers GAA band is the best response and a high PAL sublicense price holds back operators to access the PAL band. Additionally, making equal coalitions among operators can avoid overall utility loss