ITC/USA 2012 Conference Proceedings / The Forty-Eighth Annual International Telemetering Conference and Technical Exhibition / October 22-25, 2012 / Town and Country Resort & Convention Center, San Diego, California / Growing pressures on today's testing resources are driving the need for a change in the way telemetry is currently being done. As systems advance and become more complex, testing these systems becomes more difficult due to budget, schedule and test resource constraints. These pressures create the need to support more concurrent testing with ever increasing numbers of participants and bandwidth requirements, all while available resources are diminishing. In order to continue to provide support to the war fighter through timely and efficient testing of new systems, the test infrastructure needs to be updated to become more agile and efficient. We will examine the application of innovative new technologies and concepts to increase the capabilities of the testing infrastructure in the presence of shrinking resources. By leveraging advances in wireless technologies, telemetry networks and other technologies, we will present alternatives to the current telemetry paradigm.

ITC/USA 2006 Conference Proceedings / The Forty-Second Annual International Telemetering Conference and Technical Exhibition / October 23-26, 2006 / Town and Country Resort & Convention Center, San Diego, California / Research at Morgan State University shows a means of enabling both a mobile ad-hoc network (MANET) and a cellular network to operate simultaneously in the same spectrum. This enhanced frequency efficiency would facilitate the creation of a hybrid or Mixed Cellular/MANET network (MCMN) in which each of the MCMN sub-networks would have access to the entire allotted spectrum. Interference rejection and excision have been identified as a means of distinguishing between and isolating the two different kinds of signals. This paper shows the promising performance of such techniques within the MCMN environment as a part of the integrated Network Enhanced Telemetry (iNET) project.

ITC/USA 2012 Conference Proceedings / The Forty-Eighth Annual International Telemetering Conference and Technical Exhibition / October 22-25, 2012 / Town and Country Resort & Convention Center, San Diego, California / Spectrum efficiency is the key challenge in modern telemetry systems. Network telemetry requires moving from a dedicated link structure to a network structure which is a very complex problem and requires spectrum management tools. A mixed network structure has been previously proposed for networked telemetry which employs a combination of cellular and Adhoc networks. Significant improvements in QoS and clustering of the complex aeronautical networks have been observed and published in several venues. However in the earlier work routing within the Ad-hoc clusters has not been addressed and the clustering has been done using an enhanced K-means clustering. In this paper, a well known clustering algorithm is adopted in the mixed network concept and clustering of the Ad-hoc nodes are optimized based on shortest route to the gateway and minimum hop count criteria. The proposed clustering technique in this paper leads to a jointly optimized cluster-topology and gateway-selection solution a complex aeronautical network. Simulation results towards the end of this paper illustrate that with the proposed method, cluster configuration is locally optimized and the best gateway for each cluster is successfully selected. With addition of traffic measures to the consideration in the routing, the proposed solution will leads to efficient spectrum allocation and improved QoS.

<p> There are two popular approaches in the communication between multiple receivers and a base station with multiple antennas: dirty paper coding and multiuser diversity. Dirty paper coding can be rather difficult to realize, which motivates people to find some practical schemes. When there are a lot of users, multiuser diversity requires a lot of feedback which decrease the uplink spectrum efficiency.</p> <p> In this paper, we aim to minimize the probability of error subject to the total transmit power constraint and decrease the amount of feedback required by the multiuser diversity instead of trying to achieve the dirty paper coding. There are two main results in this thesis: First, we formulate the minimization of the average probability of error of all the users as a convex optimization problem, subject to the peak or the average power constraints. The proposed transmitter represents a nonlinear one-to-one mapping between the transmitted data vector and the symbol vector. The transmitted data vector going through the base station antennas is obtained as a solution to the proposed convex error probability optimization problem that can be solved using computationally efficient interior point algorithms. Furthermore, we propose a random unitary beamforming technique to reduce the feedback by selecting a threshold for the users. To improve fairness, an equal ratio scheduling algorithm which could serve the users with different rate requirements is developed. We also give an upper and lower bound on the sum rate achievable in our approach. Monte Carlo simulation results is provided to verify the performance of the proposed algorithms.</p> / Thesis / Master of Applied Science (MASc)

Modern innovation is a driving force behind increased spectrum crowding. Several studies performed by the National Telecommunications and Information Administration (NTIA), Federal Communications Commission (FCC), and other groups have proposed Dynamic Spectrum Access (DSA) as a promising solution to alleviate spectrum crowding. The spectrum assignment decisions in DSA will be made by a centralized entity referred to as as spectrum access system (SAS); however, maintaining spectrum utilization information in SAS presents privacy risks, as sensitive Incumbent User (IU) operation parameters are required to be stored by SAS in order to perform spectrum assignments properly. These sensitive operation parameters may potentially be compromised if SAS is the target of a cyber attack or an inference attack executed by a secondary user (SU). In this thesis, we explore the operational security of IUs in SAS-based DSA systems and propose a novel privacy-preserving SAS-based DSA framework, Suspicion Zone SAS (SZ-SAS), the first such framework which protects against both the scenario of inference attacks in an area with sparsely distributed IUs and the scenario of untrusted or compromised SAS. We then define modifications to the SU inference attack algorithm, which demonstrate the necessity of applying obfuscation to SU query responses. Finally, we evaluate obfuscation schemes which are compatible with SZ-SAS, verifying the effectiveness of such schemes in preventing an SU inference attack. Our results show SZ-SAS is capable of utilizing compatible obfuscation schemes to prevent the SU inference attack, while operating using only homomorphically encrypted IU operation parameters. / Master of Science / Dynamic Spectrum Access (DSA) allows users to opportunistically access spectrum resources which were previously reserved for use by specified parties. This spectrum sharing protocol has been identified as a potential solution to the issue of spectrum crowding. This sharing will be accomplished through the use of a centralized server, known as a spectrum access system (SAS). However, current SAS-based DSA proposals require users to submit information such as location and transmission properties to SAS. The privacy of these users is of the utmost importance, as many existing users in these spectrum bands are military radars and other users for which operational security is pivotal. Storing the information for these users in a central database can be an major privacy issue, as this information could be leaked if SAS is compromised by a malicious party. Additionally, malicious secondary users (SUs) may perform an inference attack, which could also reveal the location of these military radars. In this thesis, we demonstrate a SAS-framework, SZ-SAS, which allows SAS to function without direct knowledge of user information. We also propose techniques for mitigating the inference attack which are compatible with SZ-SAS

Device-to-Device (D2D) communication is one of the technologies for next generation communication system. Unlike traditional cellular network, D2D allows proximity users to communicate directly with each other without routing the data through a base station. The main aim of this study is to improve the overall energy efficiency (EE) of D2D communications overlaying cellular system. To reduce the complexity of joint EE optimization, we decompose the main EE problem into two subproblems; resource efficiency (RE) optimization in the first stage and EE optimization for D2D pairs in the second stage. Firstly, we propose an alternative two-stage RE-EE scheme for a single cellular user equipment (CUE) and a D2D pair utilizing uplink spectrum. Later, we extend this work for multiple CUEs and D2D pairs by considering the downlink orthogonal frequency division multiple access (OFDMA). By exploiting a range of optimization tools including the Bisection method, interior point algorithm, fractional programming, Dinkelbach approach, Lagrange dual decomposition, difference of convex functions, and concave-convex procedure, the original non-convex problems are solved and we present iterative two-stage RE-EE solutions. Simulation results demonstrate that the proposed two-stage scheme for uplink scenario outperforms the cellular mode and dedicated mode of communications and the performance is close to the global optimal solution. The results also show that the proposed schemes for downlink resource sharing provide improved system EE performance with significant gain on EE for D2D users compared to a two-stage EE-EE solution, which is obtained numerically. Furthermore, the RE and EE optimization for non-orthogonal multiple access (NOMA) are considered to study the effect of users' access to the whole spectrum. The results indicate that the proposed RE scheme for NOMA with D2D communications achieves higher system EE compared to the OFDMA based schemes.

Propelled by the explosive increases in mobile data traffic volume, existing wireless technologies are stretched to their capacity limits. There is a tremendous need for an expansion in system capacity and an improvement on energy efficiency. In addition, wireless network will support more and more multimedia services and applications, in which user experience has been always an important factor in evaluating the overall network performance. In order to keep pace with this explosion of data traffic and to meet the emerging quality of experience needs, wireless heterogeneous networks have been introduced as a promising network architecture evolution of the traditional cellular network. In this dissertation, we explore video quality-aware spectrum efficiency and energy efficiency in wireless heterogeneous networks|the potentials and the associated technical challenges. In particular, aiming to significantly enhance spectrum efficiency, we need to tackle the interference issue, which is exacerbated in heterogeneous network due to ultra dense node deployment as well as heterogeneity nature of various nodes. Specifically, werst study an optimal intra-cell inter-tier cooperation to mitigate interference between high power nodes and low power nodes. Together with cooperation, optimal mobile association and resource allocation schemes are also intensively investigated in heterogeneous network to achieve system load balancing so that bandwidth at high power and low power nodes can be utilized in the optimal way. The proposed scheme can greatly alleviate inter-tier interference and significantly increase overall system spectrum efficiency in a heterogeneous network. We then further apply advanced algorithms such as precoding, and non-orthogonal multiple access into intra-cell inter-tier cooperation so that the overall system spectrum efficiency and user experience are even more improved. When supporting a video type application in such a heterogeneous network, considering only spectrum efficiency is far from enough as video application is bandwidth consuming, battery consuming, and quality demanding. We develop a video quality-aware spectrum and energy efficiency resource allocation scheme in a wireless heterogeneous network and propose novel performance metrics to establish fundamental relationships among spectrum efficiency, energy efficiency, and quality of experience. Extensive simulations are conducted to evaluate the trade-o performance among three performance metrics.

Emerging 4G standards, such as WiMAX and LTE have adopted the proven technique of Adaptive Modulation and Coding (AMC) to dynamically react to channel fluctuations while maintaining bit-error rate targets of the transmission. This scheme makes use of the estimated channel state indication (CSI) to efficiently utilize channel capacity for next transmission, but it brings with it the stale CSI problem due to the frequently channel fluctuations. As its objective, this thesis focuses on mitigating the vicious effect of stale CSI by proposing a novel framework that incorporate AMC with layered transmission through Superposition Coding (SPC) is introduced. A layered multi-step finite-state Markov chain model (FSMC) is developed under this framework, to effectively assist the system in selecting the optimal modulation and coding scheme as well as the power allocated for each layer in every multi-resolution unicast transmission. Extensive simulations are conducted to verify the proposed framework and compare its performance with other counterparts. The effects of changing key parameters, such as the complexity factor and step size, are also investigated to get close to real world performance. Results demonstrate that the proposed framework can achieve better spectrum efficiency than similar counterparts, due to its improved robustness to the stale CSI problem for each multi-resolution modulated transmission, also these show that the performance of two-layer scheme is good enough for layer allocation, without need of more layers.

ITC/USA 2014 Conference Proceedings / The Fiftieth Annual International Telemetering Conference and Technical Exhibition / October 20-23, 2014 / Town and Country Resort & Convention Center, San Diego, CA / The Enhanced Query Data Recorder (EQDR) has been developed under the Test Resource Management Center's (TRMC) Spectrum Efficient Technologies (SET) T&E S&T program. The EQDR is a network flight recorder built around the iNET standards and which is intended to meet the future needs of the networked telemetry environment. The EQDR is designed to support the "fetch" of recorded test data during a test without interruption to the ongoing recording of data from the test article vehicle network. The key benefits of the network data recorder as implemented in the EQDR are increased flexibility and efficiency of test in an environment with increasing demands on spectrum available for telemetered data. EQDR enables retrieval of individual recorded parameters on an as-needed basis. Having the flexibility to send data only when it is required rather than throughout the duration of the test significantly increases the efficiency with which limited spectrum resources are used. EQDR enables parametric-level data retrieval, based not only on time interval and data source, but also on the content of the recorded data messages. EQDR enables selective, efficient retrieval of individual parameters using indexes derived from the actual values of recorded data.

ITC/USA 2013 Conference Proceedings / The Forty-Ninth Annual International Telemetering Conference and Technical Exhibition / October 21-24, 2013 / Bally's Hotel & Convention Center, Las Vegas, NV / The focus of this work is the development of a complete network architecture to enhance telemetry performance using a mobile base station (MBS). The present study proposes a means of enabling both the mobile ad-hoc network (MANET) and a cellular network to operate simultaneously within the same spectrum. In this paper the application of a modified k-means clustering to organize several hundred TAs in a complex network environment is presented. A mobile base station is added to the network to locate the congested area and support the network but positioning itself in the mixed network environment. A scenario with two base stations (one mobile and one stationary) is simulated and results are presented. It is observed that use of an additional mobile base station could greatly increase the quality of communication by providing uniform distribution of node traffic and interference across the clusters in a complex telemetry environment with several hundred TAs.