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1. Spectrum Measurement Markets for Tiered Spectrum Access

   https://doi.org/10.1109/ICC.2018.8422512  

   Ghosh, Arnob ; Berry, Randall ; Aggarwal, Vaneet ( May 2018 , 2018 IEEE International Conference on Communications (ICC))

   The recent framework for tiered spectrum sharing in the 3.5 GHz band establishes rules in which multiple firms called Environment Sensing Capability operators (ESCs) may measure spectrum occupancy and sell these measurements to other firms to help facilitate spectrum access. Motived by this we consider a scenario in which two spectrum access firms (SAs) seeks to access a shared band of spectrum and must in turn purchase spectrum measurements from one of two ESCs. Given the measurements they purchase, the SA firms then compete on price to serve customers in a shared band of spectrum. We study how differences in the quality and price of the spectrum measurements impact the resulting market equilibrium between the SAs and find that having different qualities of measurements available to different SAs can lead to better economic welfare. 

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2. Entry and Investment in CBRS Shared Spectrum

   Ghosh, A ; Berry, R ( July 2020 , 2020 18th International Symposium on Modeling and Optimization in Mobile, Ad Hoc, and Wireless Networks (WiOPT))

   null (Ed.)

   The Citizens Broadband Radio Service (CBRS) recently adopted in the U.S. enables commercial users to share spectrum with incumbent federal users. This sharing can be assisted by Environmental Sensing Capability operators (ESCs), that monitor the spectrum occupancy to determine when the use of the spectrum will not harm incumbents. An important aspect of the CBRS is that it enables two tiers of spectrum access by commercial users. The higher tier corresponds to a spectrum access (SA) firm that purchases a priority access license (PAL) in a competitive auction. The PAL holder obtains dedicated licensed access to a portion of the spectrum when the incumbent is not present. The lower tier, referred to as generalized Authorized Access (GAA), does not request a PAL and is similar to unlicensed access, in which multiple firms share a portion of the spectrum. Entry and investment in such a market introduces a number of new dimensions. Should an entrant bid for a PAL? How does the availability of a PAL impact their investment decisions? We develop a game-theoretic model to study these issues in which entrant SAs may bid in a PAL auction and decide on their investment levels and then compete downstream for customers. 

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3. Cross-Network Prioritized Sharing: An Added Value MVNO’s Perspective

   https://doi.org/10.1109/INFOCOM.2019.8737636  

   Zhu, Yining ; Yu, Haoran ; Berry, Randall A. ; Liu, Chang ( April 2019 , IEEE INFOCOM)

   We analyze the prioritized sharing between an added value Mobile Virtual Network Operator (MVNO) and multiple Mobile Network Operators (MNOs). An added value MVNO is one which earns added revenue from wireless users in addition to the revenue it directly collects for providing them wireless service. To offer service, an MVNO needs to contract with one or more MNOs to utilize their networks. Agreeing on such a contract requires the MNOs to consider the impact on their revenue from allowing the MVNO to enter the market as well as the possibility that other MNOs will cooperate. To further protect their customers, the MNOs may prioritize their direct customers over those of the MVNO. We establish a multi-stage game to analyze the equilibrium decisions of the MVNO, MNOs, and users in such a setting. In particular, we characterize the condition under which the MVNO can collaborate with the MNOs. The results show that the MVNO tends to cooperate with the MNOs when the band resources are limited and the added value is significant. When there is significant difference in band resources among the MNOs, the MVNO first considers cooperating with the MNO with a smaller band. We also consider the case when the users also have access to unlicensed spectrum. 

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4. Political Patronage and Economic Opportunity: Vertical Integration in Egyptian Textiles and Clothing

   https://doi.org/10.1057/s41287-023-00580-2  

   El-Haddad, Amirah ( May 2023 , The European Journal of Development Research)

   Utilizing an original data set, this paper demonstrates how protectionist industrial policy during the period of hybrid liberalization has shaped the organizational structure of clothing firms in Egypt. It investigates determinants of vertical integration of clothing firms into fabric production. High-end market segments are a critical determinant of integration. Limited access to finance restricts the possibilities for many firms to undertake the investment required to integrate, whilst volatile and uncertain market conditions make firms more likely to rely on the market for their inputs. But there are nuances related to market segment. Producers of higher quality garments rely on imported textiles, so these producers do not integrate even if search and switch costs are high. But the opposite is true of producers relying on domestic suppliers. Foreign institutions are better able to ensure contract enforcement with respect to quality and timely delivery so that suppliers’ opportunistic behaviour is deterred, reducing the necessity of clothing firms to integrate. This may not be the case with respect to domestic suppliers when domestic institutions do not guarantee the same level of enforcement. The adoption of the hybrid liberalization model meant that the transition to a market economy was not preceded by the creation of the necessary regulatory framework. This model resulted in inefficient upstream production and in an institutional setting conducive to agency problems. It also meant that business suffers excessive and inefficient bureaucracy. It is thus not possible for firms to achieve the first best outcome of arm’s length relations based on frictionless market transactions. Given these structural constraints firms opt for the second best solution of make rather than buy, i.e. vertical integration. But only some firms are able to use the arbitrary and discretionary decision making system to their favour, negotiating government obstacles to successful business. Those linked to power, prospered, whilst the businesses of others foundered against the wall of patronage, bureaucracy and red tape.

    

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5. TrustSAS: A Trustworthy Spectrum Access System for the 3.5 GHz CBRS Band

   https://doi.org/10.1109/INFOCOM.2019.8737533  

   Grissa, Mohamed ; Yavuz, Attila A. ; Hamdaoui, Bechir ( June 2019 , IEEE INFOCOM 2019 - IEEE Conference on Computer Communications)

   As part of its ongoing efforts to meet the increased spectrum demand, the Federal Communications Commission (FCC) has recently opened up 150 MHz in the 3.5 GHz band for shared wireless broadband use. Access and operations in this band, aka Citizens Broadband Radio Service (CBRS), will be managed by a dynamic spectrum access system (SAS) to enable seamless spectrum sharing between secondary users (SU s) and incumbent users. Despite its benefits, SAS’s design requirements, as set by FCC, present privacy risks to SU s, merely because SU s are required to share sensitive operational information (e.g., location, identity, spectrum usage) with SAS to be able to learn about spectrum availability in their vicinity. In this paper, we propose TrustSAS, a trustworthy framework for SAS that synergizes state-of-the-art cryptographic techniques with blockchain technology in an innovative way to address these privacy issues while complying with FCC’s regulatory design requirements. We analyze the security of our framework and evaluate its performance through analysis, simulation and experimentation. We show that TrustSAS can offer high security guarantees with reasonable overhead, making it an ideal solution for addressing SU s’ privacy issues in an operational SAS environment. 

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