He, Y., Dutkiewicz, E., Fang, G. & Mueck, M.D. 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.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, M.D. 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, M.D. 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, M.D. 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.