Papers by Tolga Numanoglu
Physical Communication, Dec 1, 2019
arXiv (Cornell University), Jul 31, 2017
Novel bitwise retransmission schemes are devised which retransmit only the bits received with sma... more Novel bitwise retransmission schemes are devised which retransmit only the bits received with small reliability. The retransmissions are used to accumulate the reliabilities of individual bits. Unlike the conventional automatic repeat request (ARQ) schemes, the proposed scheme does not require a checksum for the error detection. The bits to be retransmitted are reported as a combination number, or two synchronized random number generators (RNGs) at the transmitter and receiver are used to greatly compress the feedback message. The bitwise retransmission decisions and/or combining can be performed after the demodulation or after the channel decoding at the receiver. The bit-error rate (BER) expressions are derived for the case of one and two retransmissions, and verified by computer simulations. Assuming three specific retransmission strategies, the scheme parameters are optimized to minimize the overall BER. For the same number of retransmissions and packet length, the proposed schemes always outperform the frequently used stop-and-wait ARQ. The impact of feedback errors is also considered. Finally, practical designs of the bitwise retransmissions for data fusion from sensor nodes in Zigbee, Wifi and Bluetooth networks are presented.
arXiv (Cornell University), Jul 11, 2017
The metrics play increasingly fundamental role in the design, development, deployment and operati... more The metrics play increasingly fundamental role in the design, development, deployment and operation of telecommunication systems. Despite their importance, the studies of metrics are usually limited to a narrow area or a well-defined objective. Our study aims to more broadly survey the metrics that are commonly used for analyzing, developing and managing telecommunication networks in order to facilitate understanding of the current metrics landscape. The metrics are simple abstractions of systems, and they directly influence how the systems are perceived by different stakeholders. However, defining and using metrics for telecommunication systems with ever increasing complexity is a complicated matter which has not been so far systematically and comprehensively considered in the literature. The common metrics sources are identified, and how the metrics are used and selected is discussed. The most commonly used metrics for telecommunication systems are categorized and presented as energy and power metrics, quality-of-service metrics, quality-of-experience metrics, security metrics, and reliability and resilience metrics. Finally, the research directions and recommendations how the metrics can evolve, and be defined and used more effectively are outlined.
MILCOM 2017 - 2017 IEEE Military Communications Conference (MILCOM), 2017
2017 European Modelling Symposium (EMS), 2017
The metrics and measurements play a crucial role in the whole lifecycle of telecommunication netw... more The metrics and measurements play a crucial role in the whole lifecycle of telecommunication networks. The number of metrics being considered for modern telecommunication systems supporting digital or computing infrastructures has grown exponentially. It requires sophisticated systems for the metrics management which are under development by the industry consortia. For many research tasks, it would be sufficient to identify a relatively small number of recommended metrics to achieve more consistent evaluations of the system performance. There are still many unsolved problems in this area including defining the optimum modeling strategies and the metrics optimality. This paper explores a landscape of the most commonly used telecommunication and computing metrics to illuminate what metrics are available.
2018 International Conference on Communication information and Computing Technology (ICCICT), 2018
Mobile ad-hoc networks (MANETs) are deployed and operate in infrastructure-less environments. How... more Mobile ad-hoc networks (MANETs) are deployed and operate in infrastructure-less environments. However, when the nodes in such networks are aware of their locations, a shared grid of virtual cells can be defined. It is then possible to preassign these cells with communication channels and other radio resources to facilitate distributed radio resource management (RRM) and to limit the exchange of control messages. The channel allocations in virtual cells can assume similar channel reuse schemes as those used in the legacy cellular networks. Assuming that the node clusters coincide with the virtual cells, the average signal-to-interference-noise ratio (SINR) is numerically compared for a random waypoint mobility (RWM) model with a deterministic component, and two sample designs of the orthogonal frequency hopping patterns assigned to the clusters of 3 and 7 virtual cells, respectively.
ArXiv, 2017
Novel bitwise retransmission schemes are devised which retransmit only the bits received with sma... more Novel bitwise retransmission schemes are devised which retransmit only the bits received with small reliability. The retransmissions are used to accumulate the reliabilities of individual bits. Unlike the conventional automatic repeat request (ARQ) schemes, the proposed scheme does not require a checksum for the error detection. The bits to be retransmitted are reported as a combination number, or two synchronized random number generators (RNGs) at the transmitter and receiver are used to greatly compress the feedback message. The bitwise retransmission decisions and/or combining can be performed after the demodulation or after the channel decoding at the receiver. The bit-error rate (BER) expressions are derived for the case of one and two retransmissions, and verified by computer simulations. Assuming three specific retransmission strategies, the scheme parameters are optimized to minimize the overall BER. For the same number of retransmissions and packet length, the proposed sche...
ArXiv, 2017
The metrics play increasingly fundamental role in the design, development, deployment and operati... more The metrics play increasingly fundamental role in the design, development, deployment and operation of telecommunication systems. Despite their importance, the studies of metrics are usually limited to a narrow area or a well-defined objective. Our study aims to more broadly survey the metrics that are commonly used for analyzing, developing and managing telecommunication networks in order to facilitate understanding of the current metrics landscape. The metrics are simple abstractions of systems, and they directly influence how the systems are perceived by different stakeholders. However, defining and using metrics for telecommunication systems with ever increasing complexity is a complicated matter which has not been so far systematically and comprehensively considered in the literature. The common metrics sources are identified, and how the metrics are used and selected is discussed. The most commonly used metrics for telecommunication systems are categorized and presented as ene...
Broadband Communications Networks - Recent Advances and Lessons from Practice, 2018
In a transition to automated digital management of broadband networks, communication service prov... more In a transition to automated digital management of broadband networks, communication service providers must look for new metrics to monitor these networks. Complete metrics frameworks are already emerging whereas majority of the new metrics are being proposed in technical papers. Considering common metrics for broadband networks and related technologies, this chapter offers insights into what metrics are available, and also suggests active areas of research. The broadband networks being a key component of the digital ecosystems are also an enabler to many other digital technologies and services. Reviewing first the metrics for computing systems, websites and digital platforms, the chapter focus then shifts to the most important technical and business metrics which are used for broadband networks. The demand-side and supply-side metrics including the key metrics of broadband speed and broadband availability are touched on. After outlining the broadband metrics which have been standardized and the metrics for measuring Internet traffic, the most commonly used metrics for broadband networks are surveyed in five categories: energy and power metrics, quality of service, quality of experience, security metrics, and robustness and resilience metrics. The chapter concludes with a discussion on machine learning, big data and the associated metrics.
Aeu-international Journal of Electronics and Communications, Sep 1, 2016
In this paper, hierarchical modulation is used in conjunction with maximum-weight scheduling to a... more In this paper, hierarchical modulation is used in conjunction with maximum-weight scheduling to achieve lower transmission delays. Via hierarchical modulation, the scheduled user has the option to transmit to two users simultaneously. In order to reflect service differentiation schemes used in upper layers, a scenario in which each user generates packets with different priority levels is considered. It is assumed that as long as there are high priority packets waiting in the scheduled user's queue, lower priority packets cannot be transmitted. It is shown that, using hierarchical modulation in the presence of packet prioritization, average delay of low priority traffic can be reduced while achieving higher throughput. In the absence of packet prioritization, using hierarchical modulation lowers packet transmission delays without any loss in throughput. The effect of multiple access interference is also investigated. It is shown that both single and two-layer schemes have similar average spatial reuse factors.
AEU - International Journal of Electronics and Communications, 2016
In this paper, hierarchical modulation is used in conjunction with maximum-weight scheduling to a... more In this paper, hierarchical modulation is used in conjunction with maximum-weight scheduling to achieve lower transmission delays. Via hierarchical modulation, the scheduled user has the option to transmit to two users simultaneously. In order to reflect service differentiation schemes used in upper layers, a scenario in which each user generates packets with different priority levels is considered. It is assumed that as long as there are high priority packets waiting in the scheduled user's queue, lower priority packets cannot be transmitted. It is shown that, using hierarchical modulation in the presence of packet prioritization, average delay of low priority traffic can be reduced while achieving higher throughput. In the absence of packet prioritization, using hierarchical modulation lowers packet transmission delays without any loss in throughput. The effect of multiple access interference is also investigated. It is shown that both single and two-layer schemes have similar average spatial reuse factors.
Clustering and frequency allocation in frequency hopping tactical networks
MILCOM 2015 - 2015 IEEE Military Communications Conference, 2015
Next generation tactical networks has to provide high data rate and low delay, along with multipl... more Next generation tactical networks has to provide high data rate and low delay, along with multiple applications with strict QoS requirements. In this work we address the problems of clustering and frequency allocation in TDMA-based frequency-hopping tactical networks. We propose Mixed Integer Linear Programming based optimal clustering solution along with a distributively implementable load-balanced clustering algorithm. As for the frequency hop set allocation, we first propose a centralized algorithm based on full channel information. Then we propose a distributively implementable channel allocation algorithm. Simulation results reveal that the proposed algorithms perform very closely to the benchmark solutions in terms of throughput and delay.
Combined geometric and algebraic averaging for power spectral estimation
ABSTRACT
Enabling Real-Time Mobile Cloud Computing through Emerging Technologies, 2015
For military communication systems, it is important to achieve robust and energy efficient real-t... more For military communication systems, it is important to achieve robust and energy efficient real-time communication among a group of mobile users without the support of a pre-existing infrastructure. Furthermore, these communication systems must support multiple communication modes, such as unicast, multicast, and network-wide broadcast, to serve the varied needs in military communication systems. One use for these military communication systems is in support of real-time mobile cloud computing, where the response time is of utmost importance; therefore, satisfying real-time communication requirements is crucial. In this chapter, we present a brief overview of military tactical communications and networking (MTCAN). As an important example of MTCAN, we present the evolution of the TRACE family of protocols, describing the design of the TRACE protocols according to the tactical communications and networking requirements. We conclude the chapter by identifying how the TRACE protocols c...
Lecture Notes in Computer Science, 2007
Mobile ad-hoc networks (MANETs) utilize broadcast channels, where wireless transmissions occur fr... more Mobile ad-hoc networks (MANETs) utilize broadcast channels, where wireless transmissions occur from one user to many others. In a broadcast channel the same transmission can lead to different information rates to different users depending on the channel capacity between the transmitter and receiver pair. According to coding theory, there is a certain channel capacity that limits the rate of information that can be sent through the channel. Thus, different channel capacities result in different acceptable rates for the users. In this paper, we utilize a superposed coding scheme in a MANET scenario to provide different rates for users with different channel capacities using a single broadcast transmission. We have created techniques to extend this multi-rate concept to network-wide broadcasting scenarios, providing the ability for nodes to appropriately trade-off delay vs. quality. We describe our approach and provide simulation results showing the benefits and limitations of superposed coding in network-wide broadcasting.
2008 5th IEEE International Conference on Mobile Ad Hoc and Sensor Systems, 2008
Quality of Service (QoS) of a network-wide broadcast (NWB) protocol is one of the most important ... more Quality of Service (QoS) of a network-wide broadcast (NWB) protocol is one of the most important performance metrics, especially in mobile ad hoc networks, where channel conditions and network topology change frequently. We propose a mesh networking inspired approach to overcome the performance degradation caused by lossy channels. We show that our adaptive approach, whereby the amount of redundancy is adjusted to the current link conditions, can achieve good performance while simultaneously reducing unnecessary energy dissipation.
An embedded radio software emulation platform using OPNET and VxWorks to develop distributed algorithms for military ad-hoc networks
MILCOM 2012 - 2012 IEEE Military Communications Conference, 2012
ABSTRACT Military radios have been evolving from push to talk devices into multitasking, networki... more ABSTRACT Military radios have been evolving from push to talk devices into multitasking, networking capable, handheld mobile ad-hoc computers. Software defined radio technology has been fueling this evolution and as result, responsibilities and utilization of military radios along with the military network sizes have been increasing. As the complexity of ad-hoc networking radios continue to increase, the distributed protocols designed to manage the networking requirements, such as medium access control and routing, are becoming more complex and harder to analyze than they have ever been. In this paper, we present an embedded radio software emulation platform that we have developed to facilitate distributed algorithm design for military ad-hoc networks This platform enables the development and testing of distributed network protocols through emulation of the embedded software implementing these protocols. Distributed networking protocols used by the radios are emulated using the radio software's native operating system, Wind River VxWorks, which is virtualized by using Wind River Hypervisor to run on a personal computer. The remaining parts of the radio software, physical layer properties, air interface of the radio, and all networking scenario details (e.g., terrain, mobility, and user generated traffic) are implemented in OPNET, through co-simulation. Performing design, evaluation, and debugging of distributed network algorithms on this platform will significantly reduce the amount of time spent on field tests, which can require hundreds of radios and last for months for each enhanced or modified version of the algorithms.
2009 IEEE Wireless Communications and Networking Conference, 2009
Soft clustering of the nodes combined with time division multiple access (TDMA) channel access wi... more Soft clustering of the nodes combined with time division multiple access (TDMA) channel access within a cluster has been shown to provide an energy-efficient solution for Mobile Ad-Hoc Networks (MANET). Such channel access schemes use a parameter that is critical in determining network performance: the number of frames per superframe, which determines the amount of spatial reuse possible, similar to the frequency reuse factor in cellular networks. When a smaller number of frames per superframe is used, each frame will consist of a larger number of slots, enabling the frame (i.e., cluster) to support more nodes, but also limiting the choices of frames for clusterheads to select, causing higher co-channel interference and collisions. Conversely, when a larger number of frames per superframe is used, the clusterheads will only be able to grant channel access to a limited number of nodes, which in turn increases the number of dropped packets (i.e., blocked channel access). The optimum value of the number of frames is the one that minimizes the combined effect of both collisions and dropped packets. By analytically determining the effects of dropped packets and collisions, we can find the optimal value for any given scenario. This paper develops a model to determine the optimal TDMA structure under various settings, showing the advantages that can be obtained by adapting protocol parameters as network conditions change.
WiMob'2005), IEEE International Conference on Wireless And Mobile Computing, Networking And Communications, 2005., 2005
In this paper, we investigate the effects of channel noise on the performance of coordinated and ... more In this paper, we investigate the effects of channel noise on the performance of coordinated and non-coordinated MAC protocols. Comparative evaluations of these protocols under a perfect channel assumption have shown that coordinated MAC protocols, which regulate channel access locally, outperform noncoordinated channel access schemes in terms of energy efficiency and throughput. However, coordinated MAC protocols are more vulnerable than non-coordinated MAC protocols to channel noise due to their dependence on the robustness of the control traffic. In order to observe the degradation in performance of a coordinated MAC protocol (MH-TRACE), we investigate the impact of losing control packets. Furthermore, the performance in terms of throughput, delay, and energy efficiency of both coordinated (MH-TRACE) and non-coordinated (IEEE 802.11) MAC protocols is explored using a general error model that takes into account the length of the packets. Our results show that despite its higher level of vulnerability, the coordinated MAC protocol's performance is superior to the performance of the non-coordinated MAC protocol even when error rates are high.
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Papers by Tolga Numanoglu