He, Y, Jayawickrama, BA, Dutkiewicz, E, Srikanteswara, S & Mueck, M 2018, 'Priority Access and General Authorized Access Interference Mitigation in the Spectrum Access System', IEEE Transactions on Vehicular Technology, vol. 67, no. 6, pp. 4969-4983.View/Download from: UTS OPUS or Publisher's site
© 1967-2012 IEEE. To meet the capacity needs of next generation wireless communications, the U.S. Federal Communications Commission has recently introduced the spectrum access system. Spectrum is shared between three tiers - incumbents, priority access licensees (PAL), and general authorized access (GAA) licensees. When the incumbents are absent, PAL and GAA share the spectrum under the constraint that GAA ensure the interference to PAL is no more than $-$40 dBm with at least 99% confidence. We consider the scenario where locations are not shared between PAL and GAA. We propose a PAL-GAA cochannel interference mitigation technique that does not expose base station locations. Our approach relies on GAA sharing the distribution and maximum number of transmitters in a finite area. We show how PAL can derive the distribution of the aggregate interference using the probability density function and characteristic function, and notify GAA about the exclusion zones in space that will guarantee that the interference requirement is met. We also propose a numerical approximation using inverse fast Fourier and discrete Fourier transforms. Analytically calculated distribution aligns well with the numerical results. Additionally, we formulate an optimization problem for the optimal exclusion zone size. We analytically prove convexity of the problem. Our approach reduces the exclusion zone size by over 42%, which gives significantly more spectral opportunities to GAA in the spatial domain.
Jayawickrama, BA, He, Y, Dutkiewicz, E & Mueck, MD 2018, 'Scalable Spectrum Access System for Massive Machine Type Communication', IEEE NETWORK, vol. 32, no. 3, pp. 154-160.View/Download from: UTS OPUS or Publisher's site
Wang, H, Nguyen, D, Dutkiewicz, Fang & Mueck 2017, 'Negotiable Auction based on Mixed Graph: A Novel Spectrum Sharing Framework', IEEE Transactions on Cognitive Communications and Networking, vol. 3, no. 3, pp. 390-403.View/Download from: UTS OPUS or Publisher's site
Auction-based spectrum sharing is a promising solution to improve the spectrum utilization in 5G networks. Along with the spatial reuse, we observe that the ability to adjust the coverage of a spectrum bidder can provide room to itself for further negotiation while auctioning. In this paper, we propose a novel economic tool, size-negotiable auction mechanism (SNAM), which provides a hybrid solution between auction and negotiation for multi-buyers sharing spectrum chunks from a common database. Unlike existing auction-based spectrum sharing models, each bidder of the SNAM submits its bid for using the spectrum per unit space and a set of coverage ranges over which the bidder is willing to pay for the spectrum. The auctioneer then coordinates the interference areas (or coverage negotiation) to ensure no two winners interfere with each other while aiming to maximize the auction's total coverage area or revenue. In this scenario, the undirected graph used by existing auction mechanisms fails to model the interference among bidders. Instead, we construct a mixed interference graph and prove that SNAM's auctioning on the mixed graph is truthful and individually rational. Simulation results show that, compared with existing auction approaches, the proposed SNAM dramatically improves the spatial efficiency, hence leads to significantly higher seller revenue and buyer satisfaction under various setups. Thanks to its low complexity and low overhead, SNAM can target fine timescale trading (in minutes or hours) with a large number of bidders and requested coverages.
Cheng, Q, Nguyen, D, Dutkiewicz, E & Mueck, MD 2018, 'Protecting Operational Information of Incumbent and Secondary Users in FCC Spectrum Access System', International Conference on Communications, IEEE, Kansas City, MO, USA.View/Download from: UTS OPUS or Publisher's site
Both Federal Communications Commission (FCC) and European Telecommunications Standards Institute (ETSI) support dynamic spectrum access (DSA) as an enabling technology for spectrum sharing. To effectively realize DSA in practice, users (from both defense and civil sectors) are required to share their (radio) operational information. That risks exposing their security, privacy, and business plan to unintended agents. In this paper, taking FCC's spectrum access system (SAS) as a study case, we propose a privacy-preserving scheme for DSA by leveraging encryption and obfuscation methods (PSEO). To implement PSEO, we propose an interference calculation scheme that allows users to calculate interference budget without revealing their operation information (e.g., antenna height, transmit power, location...), referred to as blind interference calculation method (BICM). BICM also reduces the computing overhead of PSEO, compared with FCC's SAS by moving interference budgeting tasks to local users and calculating it in an offline manner. Extensive detailed analysis and simulations show that our proposed PSEO is able to better protect all users' operational privacy, guaranteeing efficient spectrum utilization with less online overhead, compared with state of the art approaches.
Basnet, S, Jayawickrama, BA, He, Y, Dutkiewicz, E & Mueck, MD 2017, 'Opportunistic Access to PAL Channel for Multi-RAT GAA Transmission in Spectrum Access System', IEEE Vehicular Technology Conference, IEEE Vehicular Technology Conference, IEEE, Sydney, NSW, Australia, pp. 1-5.View/Download from: UTS OPUS or Publisher's site
© 2017 IEEE. Spectrum Access System (SAS) is a three tier spectrum sharing framework proposed by the FCC. In this framework the aggregate interference of tier-3 General Authorised Access (GAA) users should be below a predetermined threshold anywhere within the tier-2 Priority Access Licensee (PAL) exclusion zone. GAA are expected to use a diverse range of Radio Access Technologies (RATs) with different levels of loading. We propose an optimal transmit power and probability of spectrum utilisation allocation scheme for GAA users that meets the average aggregate interference constraint within the GAA network. Most of the capacity maximisation studies consider the instantaneous aggregated interference from secondary users. In this paper we present an average aggregated interference method to optimise the capacity of GAA users in a single channel. Simulation results suggest that we can significantly increase the capacity of the channel by considering the probability spectrum utilisation of GAA users.
Cheng, Nguyen, D, Dutkiewicz & Mueck 2017, 'Preserving Operational Information in Spectrum Access System with Dishonest Users', 2017 17th International Symposium on Communications and Information Technologies (ISCIT), International Symposium on Communications and Information Technologies, IEEE, Cairns, QLD, Australia.View/Download from: UTS OPUS or Publisher's site
Privacy has been regarded as one of the most critical issues in light of promoting the development of centralized spectrum management, hence attracting wide attention. However, researchers in the current literature are usually protecting users' privacy based on the assumption that all users are honest, which is reasonable but not practical. In this paper, we investigate the privacy issue among different tiers of users in the centralized spectrum access system (SAS), mainly focusing on honest Priority Access Licenses (PALs) and dishonest General Authorized Accesses (GAAs). To that end, we propose an authentication scheme to prevent GAAs from using other users' information by the aid of a public key cryptosystem. Moreover, we propose a 'punishment and forgiveness' scheme, which draws support from GAAs' reputation stores (RSs) and reputation histories (RHs), to encourage GAAs to engage in positive and true activities. Besides, we propose a privacy preservation scheme cooperating with the 'punishment and forgiveness' scheme (PS-PFS) in order to effectively mitigate the impact of dishonest users while fully preserving all users' privacy as well as successfully realizing spectrum sharing.
Haider, N, Dutkiewicz, E, Nguyen, DN, Mueck, M & Srikanteswarae, S 2017, 'The Impact on Full Duplex D2D Communication of Different LTE Transmission Techniques', 2017 IEEE 85th Vehicular Technology Conference (VTC Spring), IEEE Vehicular Technology Conference, IEEE, Sydney, Australia, pp. 1-5.View/Download from: UTS OPUS or Publisher's site
To augment capacity of spectrum limited cellular systems, 3GPP proposed Licensed Assisted Access (LAA-LTE) while efforts are underway to standardize the standalone MulteFire (a small cell standalone version of LTE). LAA is expected to boost capacity of LTE via unlicensed spectrum (5GHz). On the other hand, recent advances in Self Interference Suppression (SIS) techniques allow radios to transmit and receive simultaneously on the same channel (i.e., in-band Full-Duplex, FD). As part of future wireless networks, Device-to-device (D2D) communications would find its great potential through this FD capability. However, due to high induced aggregate interference from FD and its impact on medium access probability, the rigorous and critical analysis is needed to find an optimum trade-off between performance efficiency and overheads. Using stochastic geometry and the random graph theory, in this article, we analyze the impact of different LTE network paradigms with HD/FD D2D devices. Moreover, the impact of state- of-the-art coexistence techniques (discontinuous transmission and listen-before-talk) recommended for LTE in unlicensed spectrum over HD/FD D2D network is also discussed. The analysis is supported with extensive simulation results that reveal insights of the coexistence mechanism efficiency employed by LTE, the impact of SIS and the cost of FD operation in D2D.
Wang, H, Dutkiewicz, E, Jayawickrama, BA & Mueck, MD 2017, 'Design of Contour Based Protection Zones for Sublicensing in Spectrum Access Systems', IEEE Vehicular Technology Conference, IEEE Vehicular Technology Conference, IEEE, Sydney, NSW, Australia, pp. 1-5.View/Download from: UTS OPUS or Publisher's site
© 2017 IEEE. Spectrum Access System (SAS) allows incumbent military systems to share spectrum in a hierarchical manner with tier-2 Priority Access License (PAL) users and tier-3 General Authorized Access (GAA) users. FCC has recently allowed PAL owners to sublicense their channels. Therefore, when GAA channels are congested they can request a sublicense to access the PAL channel on a coordinated basis, which provides interference protection from other GAA users. In this paper, we propose a grid map to measure and monitor the secondary spectrum market for the purpose of spectrum trading with QoS guarantee. This work provides the subsequent spectrum trading models with a reasonable and dedicated interference graph for further optimization of spectrum allocation. Compared with traditional longterm spectrum licensing policy, short-term licensing makes the spectrum allocated effectively. We find the optimal resolution of the discrete grid map that maximizes the profit from sublicensing. Simulation results are provided to demonstrate how fine to grid the region and let the PAL owner achieve monetary benefit, in a given number of sensors.
Wang, H, Dutkiewicz, E, Jayawickrama, BA & Mueck, MD 2017, 'Detection of contour boundary for sublicensing in spectrum access systems', 2017 17th International Symposium on Communications and Information Technologies, ISCIT 2017, International Symposium on Communications and Information Technologies, IEEE, Cairns, QLD, Australia, pp. 1-5.View/Download from: UTS OPUS or Publisher's site
© 2017 IEEE. Associated to database and a local centralized system, the short-term spectrum sublicensing is one of the potential approaches to improve the spectrum efficiency in the 5G networks. If the sublicences are assigned to the heterogeneous base stations that are from different operators, the interference issue becomes challenging to tackle. In this paper, we propose a solution of contour boundary detection for sublicensing to coordinate the interference among heterogeneous base stations in the space domain. As the direct access points to sever the end users, the base stations know and even could predict the traffic requirements over their coverage areas. Therefore, we enable individual base station as a sublicensee based on self-reported protection contour and optimize the best allocation for the system to guarantee the interference-free operations among those who spatially use the same sublicense simultaneously. Considering the selfish behaviours of base stations, we employ the sensor networks to monitor and measure their contours. Then we estimate the contour boundary by detecting the inner and outer contour boundary. Finally we compare the estimation accuracies of different sensor networks and demonstrate an interference-free allocation for the sublicensees.
Wang, H, Nguyen, D, Dutkiewicz & Mueck 2017, 'Game Theoretic Analysis of Sublicensing for PAL and GAA Bands in Spectrum Access System', 28th Annual IEEE International Symposium on Personal, Indoor and Mobile Radio Communications (IEEE PIMRC 2017), IEEE International Symposium on Personal, Indoor and Mobile Radio Communications, IEEE, Montreal, QC, Canada.View/Download from: UTS OPUS or Publisher's site
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 noncooperative 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.
He, Y, Dutkiewicz, E, Fang, G & Mueck, MD 2016, 'SNR threshold for distributed antenna systems in Cloud Radio Access Networks', 2015 IEEE 82nd Vehicular Technology Conference, VTC Fall 2015 - Proceedings, IEEE Vehicular Technology Conference, IEEE, Boston, MA.View/Download from: UTS OPUS or Publisher's site
© 2015 IEEE. A distributed antenna system (DAS) architecture is a key enabler for Cloud Radio Access Networks (CRAN) where geographically separated base stations are connected to a centralized processing and decision making unit. Many schemes have been proposed to leverage Fractional Frequency Reuse (FFR) and co-ordinated joint transmission between base stations to improve cell-edge performance for static network deployments. In this paper, we investigate dynamic decision making that whether co-ordinated joint transmission should be selected in the downlink of a FFR-aided DAS. We derive the transmitting Signal-to-Noise-Ratio (SNR) threshold that co-ordinated joint transmission can provide better performance if the transmitting SNR is below this threshold. We simulated a three-cell cluster layout with FFR and the numerical results agree with our analytical results. We show that the transmitting SNR threshold is critical in the FFR-aided DAS analysis and can be used as a guide in the CRAN network planning and the evaluation of DAS performance.
Wang, H, Dutkiewicz, E, Fang, G & Mueck, MD 2016, 'A Fair Spectrum Sharing Framework Based on Topological Sort and Max Weight for Femtocells', 2016 Australian Communications Theory Workshop, AusCTW 2016, Australian Communications Theory Workshop, IEEE, Monash University, Australia.View/Download from: Publisher's site
Femto base stations will be widely deployed in 5G times for compensating poor cellular coverage for use in residential or small business environments. In this paper, we propose a spectrum sharing framework, where a cluster of femtocells are under the control of a centralized local manager. The framework assumes that each femto base station has the sniffing ability that can detect its neighbor femtocells and the controller can then have complete knowledge of local interference constraints. Unlike distributed WiFi that runs on unlicensed band, the femtocell owned by a carrier runs on licensed band and the carrier prefers a centralized system to a distributed one. Therefore, a fair spectrum sharing policy on the licensed band is more important among carriers to break the monopoly and inefficient spectrum allocation. Considering the spectrum can be spatial reused, an interference graph is adopted to avoid the interference between femtocells of all the carriers. We test the framework not only by comparing the average number of channels per user can get but also the variance to guarantee the fairness. In this framework, the scheme combining topological sort and maximum traffic load of femtocell contributes to keep a better balance on the average number of channels and variance.
Wang, H, Dutkiewicz, E, Fang, G & Mueck, MD 2015, 'Spectrum sharing based on truthful auction in licensed shared access systems', 2015 IEEE 82nd Vehicular Technology Conference, VTC Fall 2015 - Proceedings, IEEE Vehicular Technology Conference, IEEE, USA.View/Download from: UTS OPUS or Publisher's site
© 2015 IEEE. The explosion of different types of wireless communications is leading to an impending spectrum famine. As a result, spectrum sharing has gained increasing interest from governments, industry and regulators, such as FCC in US and CEPT in Europe. Licensed Shared Access (LSA), developed by CEPT and ETSI, is a concept for an efficient use of current spectrum resources to enable keeping pace with increasing mobile data usage demands. In this paper, we present a truthful auction mechanism for spectrum sharing based on the LSA concept. This proposal is to allocate Incumbents' idle spectrum to Licensee Access Points from different operators for the purpose of commerce. We give insights into spectrum allocation methods based on auction mechanisms to obtain high revenue to attract Incumbents to join in the LSA architecture and operators to offload data from primary spectrum band. The proposed LSA Auction (LSAA) mechanism combines independent set selection by bidding and an elaborately designed group bid called Rank-bid, which further improves the revenue compared to related allocation methods. Our simulation results show that LSAA results in enhanced performance for Incumbent revenue and Licensee satisfaction.
Wang, H, Dutkiewicz, E, Fang, G & Mueck, MD 2015, 'An auction framework based on flexible transmit powers in the Licensed Shared Access Systems', 2015 15th International Symposium on Communications and Information Technologies (ISCIT), International Symposium on Communications and Information Technologies, IEEE, Japan.View/Download from: UTS OPUS or Publisher's site
Wang, H, Dutkiewicz, E, Fang, G & Mueck, MD 2015, 'Framework of joint auction and mixed graph for Licensed Shared Access systems', 2015 IEEE International Symposium on Dynamic Spectrum Access Networks, DySPAN 2015, IEEE International Dynamic Spectrum Access Networks Symposium, IEEE, Stockholm, Sweden, pp. 154-163.View/Download from: UTS OPUS or Publisher's site
© 2015 IEEE. Licensed Shared Access offers an opportunity to further increase data rates in 5G networks. Considering that different commercial operators have no knowledge of each other, their base stations should be coordinated by a management entity to enable them to access the licensed shared spectrum without interference. An auction mechanism is often used as an efficient tool for resource allocation where rivalry is high. In this paper, we propose an on-line auction framework using a mixed graph due to the spatial reusability of spectrum. This proposed scheme allows each base station to make a concession by asking for a second shrinking interference-free area if its initial area overlaps some other base stations. We use a mixed graph to model the interference between them, because a mixed graph can quantify the interference much closer to the practical cases than an undirected graph does. We also propose to take the bid comparison into account when grouping the independent nodes in the interference graph. These two feathers together make the spectrum spatial efficiency improved, which leads to a higher revenue and a better buyer satisfaction.