Beeshanga received BEng in Telecommunications Engineering (Hons I) and PhD in Electronic Engineering (Wireless Communications) degrees from Macquarie University, Sydney, Australia, in 2011 and 2015 respectively.
Following his PhD he held a Research Associate position in the Department of Engineering at Macquarie University. He is currently a Lecturer in the School of Computing and Communications, University of Technology Sydney.
He has close ongoing industry relationships with Intel Labs and CSIRO. He has over 4 years of experience working on 802.11 and cellular networks. His research interests are resource allocation in wireless networks, cognitive radio, compressed sensing and cross-layer techniques.
Additionally he has over 5 years of experience in teaching multiple Electronic and Telecommunications Engineering subjects at Macquarie University and Sydney Institute of Business and Technology.
Beeshanga is the recipient of Macquarie University Medal in Engineering and Vice-Chancellor’s Commendation for Academic Excellence.
- Resource allocation in wireless networks
- Cognitive radio networks
- Spectrum sensing
- Compressed sensing
- Cross-layer techniques
- Radio environment maps
Spectrum Access System (SAS) Spectrum Sharing With Fine-grained Protection/Exclusion Zone Differentiation.
Patent status: US provisional patent application filed (2018) - Reg. No. 71,803.
An Access Node Controller, an Apparatus for an Access Node, an Access Node for a Mobile Communication System, a Mobile Communication System, a Method and Computer Program for an Access Node.
Patent status: US patent application filed (2017) - US15/638,491.
Allocating Wireless Channels.
Patent status: US patent application filed (2017) - US15/474,606.
Methods and Devices for Shared Spectrum Allocation.
Patent status: International (PCT) patent application filed (2016) - P86319DE/P86319PCT.
Methods and Devices for User Detection in Spectrum Sharing.
Patent status: US patent application filed (2016) - P97272.
SAS PAL GAA Co-channel Interference Mitigation.
Patent status: US provisional patent application filed (2016) - P98713Z.
Uplink Interference Management in Shared Spectrum Networks.
Patent status: US patent application filed (2015) - P86405.
Methods for Performing Mobile Communications Mobile Terminal Devices, Base Stations, and Network Control Devices.
Patent status: International (PCT) patent application filed (2015) - P86127DE/P86127PCT.
Communication Device and Method for Communicating using a Frequency Range.
Patent status: US patent application filed (2015) - P83877.
- Signal Buffering for Licensed Shared Access, US9491634, Nov. 2016.
He, Y., Jayawickrama, B.A., Dutkiewicz, E., Srikanteswara, S. & Mueck, M.D. 2018, 'Priority Access and General Authorised Access Interference Mitigation in Spectrum Access System', IEEE Transactions on Vehicular Technology.View/Download from: Publisher's site
IEEE To meet the capacity needs of next generation wireless communications, U.S. Federal Communications Commission has recently introduced Spectrum Access System. Spectrum is shared between three tiers - Incumbents, Priority Access Licensees (PAL) and General Authorised 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 co-channel 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 aggregated interference using 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.
IEEE Future 5G networks aspire to enable new services with vastly different data rate, latency and scalability requirements. The consensus is that these new services will fall into three categories: eMBB, URLLC, and mMTC. Due to unique characteristics of these services and the limited availability of finite spectrum resources, 5G will need to carefully map appropriate bands and spectrum usage models for each service. The SAS is an emerging spectrum sharing model that is gaining momentum in the U.S. SAS presents an opportunity for operators to access the 3.5 GHz military radar band for commercial use. This article discusses the feasibility of the current SAS model in the context of mMTC. We propose a scalable SAS framework that can manage the mMTC uplink interference to the incumbent with less overhead. The simulation setup models the interference levels in New York City and its surrounding counties. The results show that mMTC uplink transmission can be enabled using our framework even on the coast of New York, where mMTC density is high, without causing a harmful level of interference to the incumbent.
Jayawickrama, B.A., Dutkiewicz, E., Mueck, M. & He, Y. 2016, 'On the Usage of Geolocation Aware Spectrum Measurements for Incumbent Location and Transmit Power Detection', IEEE Transactions on Vehicular Technology, vol. 65, no. 10, pp. 8177-8189.View/Download from: UTS OPUS or Publisher's site
Determining the geographical area that needs to be excluded due to incumbent activity is critical to realize high spectral utilization in spectrum sharing networks. This can be achieved by estimating the incumbent location and transmit power. However, keeping the hardware complexity of sensing nodes to a minimum and scalability are critical for spectrum sharing applications with commercial intent. We present a discrete-space l1-norm minimization solution based on geolocation-aware energy detection measurements. In practice, the accuracy of geolocation tagging is limited. We capture the impact as a basis mismatch and derive the necessary condition that needs to be satisfied for successful detection of multiple incumbents' location and transmit power. We find the upper bound for the probability of eliminating the impact of limited geolocation tagging accuracy in a lognormal shadow fading environment, which is applicable to all generic I1-norm minimization techniques. We propose an algorithm based on orthogonal matching pursuit that decreases the residual in each iteration by allowing a selected set of basis vectors to rotate in a controlled manner. Numerical evaluation of the proposed algorithm in a Licensed Shared Access (LSA) network shows a significant improvement in the probability of missed detection and false alarm.
Basnet, S., Jayawickrama, B.A., He, Y., Dutkiewicz, E. & Mueck, M.D. 2017, 'Opportunistic Access to PAL Channel for Multi-RAT GAA Transmission in Spectrum Access System', IEEE Vehicular Technology Conference.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.
Dutkiewicz, E., Jayawickrama, B.A. & He, Y. 2017, 'Radio spectrum maps for emerging IoT and 5G networks: Applications to smart buildings', ICECOS 2017 - Proceeding of 2017 International Conference on Electrical Engineering and Computer Science: Sustaining the Cultural Heritage Toward the Smart Environment for Better Future, pp. 7-9.View/Download from: Publisher's site
© 2017 IEEE. The high demand for wireless Internet including emerging Internet of Things (IoT) applications is putting extreme pressure on better utilisation of the available radio spectrum. The expected spectrum 'crunch' requires highly efficient radio resource management schemes with low complexity and high responsiveness to the changing network conditions. Spectrum sharing is regarded as an essential approach to regaining access to otherwise unused spectrum and it is considered an essential component in the development of IoT and 5G networks. Spectrum sharing can be conducted at different time scales. As the time scale of the operation of spectrum sharing decreases, the possibility for utilising more available spectrum holes increases. However, the shorter time scale brings with it challenges. Efficient decisions regarding the use of spectrum sharing require accurate knowledge of the spatial and temporal spectrum use in a geographical area of interest. This knowledge can be represented in Radio Spectrum Maps which need to be generated efficiently and accurately. In this paper we give an overview of the spectrum sharing concept for IoT and 5G networks. We also present our research on spectrum sharing to enable Smart Building IoT applications.
Wang, H., Dutkiewicz, E., Jayawickrama, B.A. & Mueck, M.D. 2017, 'Design of Contour Based Protection Zones for Sublicensing in Spectrum Access Systems', IEEE Vehicular Technology Conference.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.
Jayawickrama, B.A., Dutkiewicz, E. & Mueck, M. 2015, 'Incumbent User Active Area Detection for Licensed Shared Access', Proceedings of the 2015 IEEE 82nd Vehicular Technology Conference (VTC Fall), IEEE Vehicular Technology Conference, IEEE, Boston, USA, pp. 1-5.View/Download from: UTS OPUS or Publisher's site
Print Request Permissions Licensed Shared Access is a European standardisation effort which promotes repository based quasi-static hierarchical spectrum sharing. In this scheme the sharing time base is in the order of months if not years. For widespread use of Licensed Shared Access, shrinking the sharing time base is crucial. In this paper we propose a scheme to reduce the sharing time base to seconds or minutes scale. We present a new technique named lightweight Radio Environment Map based on a Kalman Filter derived from geo-location aware spectrum measurements, which can be run at the shared access licensee end. Our objective is to determine the active area of a static or slowly moving incumbent. We consider a challenging scenario where a large fraction of measurements is missing and the available measurements are highly distorted. Performance of our incumbent active area detection approach is evaluated by simulating a low power incumbent in an urban cellular environment. Simulation results show a substantial improvement of missed detection area in comparison to the counterpart that does not use our lightweight Radio Environment Map.
Jayawickrama, B.A., Dutkiewicz, E., Oppermann, I. & Mueck, M. 2014, 'Iteratively Reweighted Compressive Sensing Based Algorithm for Spectrum Cartography in Cognitive Radio Networks', 2014 IEEE Wireless Communications and Networking Conference (WCNC), IEEE Wireless Communications and Networking Conference, IEEE, Istanbul, Turkey.View/Download from: UTS OPUS or Publisher's site
Jayawickrama, B.A., Dutkiewicz, E., Oppermann, I., Mueck, M. & Fang, G. 2013, 'Downlink Power Allocation Algorithm for Licence-exempt LTE Systems Using Kriging and Compressive Sensing Based Spectrum Cartography', 2013 IEEE Global Communications Conference (GLOBECOM), IEEE Global Telecommunications Conference, IEEE, Atlanta, GA, USA.View/Download from: UTS OPUS or Publisher's site
Licence-exempt secondary Long Term Evolution systems have been proposed recently, in attempt to meet the needs of rapidly growing wireless mobile applications. However, where the secondary network is spread over a large geographical area, traditional detect-and-avoid algorithms are less effective in providing interference protection to Primary Users while maximising the secondary throughput. Spectrum cartography is an emerging technique that can be used to discover spectrum holes in space. We propose a downlink power allocation algorithm using Kriging Spatial Interpolation and Compressive Sensing based spectrum cartography in an environment where large scale shadow fading is prominent. We evaluate the performance of our approach by simulating a secondary Urban Microcell network operating in TV White Space. Simulation results show a significant improvement in interference and throughput, in comparison to traditional detect-and-avoid algorithms.
Jayawickrama, B.A., Dutkiewicz, E., Oppermann, I., Fang, G. & Ding, J. 2013, 'Improved performance of spectrum cartography based on compressive sensing in cognitive radio networks', 2013 IEEE International Conference on Communications (ICC), IEEE International Conference on Communications, IEEE, Budapest, Hungary.View/Download from: UTS OPUS or Publisher's site
Spectrum cartography is the process of constructing a map showing Radio Frequency signal strength over a finite geographical area. Multiple research groups have recently proposed to use spectrum cartography in the context of discovering spectrum holes in space that can be exploited locally in cognitive radio networks. In our novel approach, we exploit the sparsity of primary users in space to formulate the cartography process as a compressive sensing problem. Further, we present a novel algorithm for solving the cartography problem that builds on the well-known Orthogonal Matching Pursuit algorithm. We evaluate the performance of our approach by simulating a cognitive radio network where primary users are low power wireless microphones. Our simulation results show a significant improvement in reconstruction error, in comparison to two existing compressive sensing based methods.
Jayawickrama, B.A., Dutkiewicz, E. & Fang, G. 2012, 'Spectrum Sensing Error Optimisation in Cognitive Radio Networks', 2012 International Symposium on Communications and Information Technologies, ISCIT 2012, International Symposium on Communications and Information Technologies, IEEE, Gold Coast, Australia.View/Download from: UTS OPUS or Publisher's site
- Intel Labs - Portland
- Intel Mobile Communications - Munich