References of "Sharma, Shree Krishna 50003084"
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See detailSANSA - Hybrid Terrestrial-Satellite Backhaul Network: Scenarios, Use cases, KPIs, Architecture, Network and Physical Layer Techniques
Ziaragkas, Georgios; Poziopoulou, Georgia; Núñez-Martínez, Jose et al

in International Journal of Satellite Communications and Networking (2017)

SANSA (Shared Access terrestrial-satellite backhaul Network enabled by Smart Antennas) is a project funded by the EU under the H2020 program. The main aim of SANSA is to boost the performance of mobile ... [more ▼]

SANSA (Shared Access terrestrial-satellite backhaul Network enabled by Smart Antennas) is a project funded by the EU under the H2020 program. The main aim of SANSA is to boost the performance of mobile wireless backhaul networks in terms of capacity, energy efficiency and resilience against link failure or congestion while easing the deployment in both rural and urban areas and assuring at the same time an efficient use of the spectrum. This paper provides an overview and the first results of the project and, more specifically, it describes the regulatory environment, the State of The Art of mobile backhauling technologies regarding Ka band, the scenarios, the use cases, and the KPIs along with the SANSA architecture, network (NET), and physical (PHY) layer techniques used to enhance wireless backhauling capabilities. [less ▲]

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See detailAnalysis of Power Quality Signals Using An Adaptive Time-Frequency Distribution
Khan, Nabeel A.; Baig, F.; Nawaz, S.J. et al

in Energies (2016)

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See detailTerminal-side interference mitigation for spectral coexistence of satellite and terrestrial systems in non-exclusive Ka-band
Sharma, Shree Krishna UL; Chatzinotas, Symeon UL; Ottersten, Björn UL

in 34th AIAA International Communications Satellite Systems Conference (2016, October)

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See detailCompressed Sensing of Sparse Multipath MIMO Channels with Superimposed Training Sequence
Amin, B.; Mansoor, B.; Junaid Nawaz, S. et al

in Wireless Personal Communications (2016)

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See detailUniversal Intelligent Small Cell for Next Generation Cellular Networks
Patwary, M.; Sharma, Shree Krishna UL; Chatzinotas, Symeon UL et al

in Digital Communications and Networks (2016), 2(4), 167174

Exploring innovative cellular architectures to achieve enhanced system capacity and good coverage has become a critical issue towards realizing the next generation of wireless communications. In this ... [more ▼]

Exploring innovative cellular architectures to achieve enhanced system capacity and good coverage has become a critical issue towards realizing the next generation of wireless communications. In this context, this paper proposes a novel concept of Universal Intelligent Small Cell (UnISCell) for enabling the densification of the next generation of cellular networks. The proposed novel concept envisions an integrated platform of providing a strong linkage between different stakeholders such as street lighting networks, landline telephone networks and future wireless networks, and is universal in nature being independent of the operating frequency bands and traffic types. The main motivating factors for the proposed small cell concept are the need of public infrastructure re-engineering, and the recent advances in several enabling technologies. First, we highlight the main concepts of the proposed UnISCell platform. Subsequently, we present two deployment scenarios for the proposed UnISCell concept considering infrastructure sharing and service sharing as important aspects. We then describe the key future technologies for enabling the proposed UnISCell concept and present a use case example with the help of numerical results. Finally, we conclude this article by providing some interesting future recommendations. [less ▲]

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See detailCognitive Interference Management Techniques for the Spectral Co-existence of GSO and NGSO Satellites
Pourmoghaddaslangroudi, Ameneh UL; Sharma, Shree Krishna UL; Chatzinotas, Symeon UL et al

in International Conference on Wireless and Satellite Systems (WiSATS, formerly PSATS), Cardiff, UK, Sep 2016 (2016, September 19)

One of the main challenges in the co-existence of geostationary satellite orbit (GSO) and non-geostationary satellite orbit (NGSO) satellite networks is to mitigate the in-line interference caused by an ... [more ▼]

One of the main challenges in the co-existence of geostationary satellite orbit (GSO) and non-geostationary satellite orbit (NGSO) satellite networks is to mitigate the in-line interference caused by an NGSO satellite to the GSO earth terminal, while the NGSO satellite is crossing the GSO satellite's illumination zone. The method recommended in ITU-R S.1325-3 involves utilizing a range-based power control on the NGSO satellite for downlink communication to the NGSO earth terminals. In this paper, we investigate a cognitive range-based power control algorithm while taking into account the imposed interference level to the GSO fixed satellite service (FSS) system. Results show that the proposed cognitive power control algorithm can mitigate the harmful in-line interference on the GSO terminal receiver, while also providing the desired link quality for the NGSO system. More importantly, we formulate and solve an optimization problem with the objective of minimizing the inter-site distance (ISD) of the GSO-NGSO earth user-terminals. Finally, we develop an analytical method to calculate the ISD between GSO and NGSO earth terminals and validate this with the help of simulation results. [less ▲]

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See detailOn the Performance Analysis of Underlay Cognitive Radio Systems: A Deployment Perspective
Kaushik, A.; Sharma, Shree Krishna UL; Chatzinotas, Symeon UL et al

in IEEE Transactions on Cognitive Communications and Networking (2016), 2(3), 273-287

We study the performance of a cognitive underlay system (US) that employs a power control mechanism at the secondary transmitter (ST) from a deployment perspective. Existing baseline models considered for ... [more ▼]

We study the performance of a cognitive underlay system (US) that employs a power control mechanism at the secondary transmitter (ST) from a deployment perspective. Existing baseline models considered for performance analysis either assume the knowledge of involved channels at the ST or retrieve this information by means of a band manager or a feedback channel; however, such situations rarely exist in practice. Motivated by this fact, we propose a novel approach that incorporates estimation of the involved channels at the ST in order to characterize the performance of the US in terms of interference power received at the primary receiver and throughput at the secondary receiver (or secondary throughput). Moreover, we apply an outage constraint that captures the impact of imperfect channel knowledge, particularly on the uncertain interference. Besides this, we employ a transmit power constraint at the ST to classify the operation of the US in terms of an interference-limited regime and a power-limited regime. In addition, we characterize the expressions of the uncertain interference and the secondary throughput for the case where the involved channels encounter Nakagami-m fading. Finally, we investigate a fundamental tradeoff between the estimation time and the secondary throughput depicting an optimized performance of the US. [less ▲]

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See detailPerformance Analysis of Interweave Cognitive Radio Systems with Imperfect Channel Knowledge over Nakagami Fading Channels
Kaushik, A.; Sharma, Shree Krishna UL; Chatzinotas, Symeon UL et al

in 2016 IEEE 84th Vehicular Technology Conference: VTC2016-Fall (2016, September)

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See detailSquare-Law Selector and Square-Law Combiner for Cognitive Radio Systems: An Experimental Study
Rodes, L.; Kaushik, A.; Sharma, Shree Krishna UL et al

in IEEE 84th Vehicular Technology Conference: VTC2016-Fall (2016, September)

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See detailPhysical Layer Aspects of Wireless IoT
Sharma, Shree Krishna UL; Bogale, Tadilo E.; Chatzinotas, Symeon UL et al

in 13th International Symposium on Wireless Communication Systems (2016, September)

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See detailCompressive Sensing Based Energy Detector
Lagunas, Eva UL; Sharma, Shree Krishna UL; Chatzinotas, Symeon UL et al

in European Signal Processing Conference (EUSIPCO) (2016, August)

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See detailImpact of Transceiver Hardware Impairments on the Ergodic Channel Capacity for Rayleigh-Product MIMO Channels
Papazafeiropoulos, Anastasios; Sharma, Shree Krishna UL; Chatzinotas, Symeon UL et al

in Proceedings of IEEE SPAWC 2016 (2016, July)

This paper aims at a realistic evaluation of Rayleighproduct multiple-input multiple-output (MIMO) systems. Specifically, by considering the residual transceiver hardware impairments into account, we ... [more ▼]

This paper aims at a realistic evaluation of Rayleighproduct multiple-input multiple-output (MIMO) systems. Specifically, by considering the residual transceiver hardware impairments into account, we derive the ergodic channel capacity of a MIMO system with optimal receivers in the case of insufficient scattering. Actually, motivated by the increasing interest for massive MIMO systems, we investigate the impact of transceiver hardware imperfections in systems with both finite (conventional) and large number of antennas under rank deficient channel matrix conditions by varying the severity of hardware quality. Among the interesting outcomes, we emphasize that the residual hardware transceiver impairments result to a saturation of the ergodic channel capacity within the high signal-to-noise ratio (SNR) regime. Furthermore, we observe that the higher the “richness” of the scattering environment, the higher the ergodic channel capacity till it gets saturated. [less ▲]

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See detailPerformance analysis of hybrid cognitive radio systems with imperfect channel knowledge
Kaushik, A.; Sharma, Shree Krishna UL; Chatzinotas, Symeon UL et al

in Communications (ICC), 2016 IEEE International Conference on (2016, July)

In this paper, we study the performance of hybrid cognitive radio systems that combine the benefits of interweave and underlay systems by employing a spectrum sensing and a power control mechanism at the ... [more ▼]

In this paper, we study the performance of hybrid cognitive radio systems that combine the benefits of interweave and underlay systems by employing a spectrum sensing and a power control mechanism at the Secondary Transmitter (ST). Existing baseline models considered for performance analysis assume perfect knowledge of the involved channels at the ST, however, such situations hardly exist in practical deployments. Motivated by this fact, we propose a novel approach that incorporates channel estimation at the ST, and consequently characterizes the performance of Hybrid Systems (HSs) under realistic scenarios. To capture the impact of imperfect channel knowledge, we propose outage constraints on the detection probability at the ST and on the interference power received at the primary receiver. Our analysis reveals that the baseline model overestimates the performance of the HS in terms of achievable secondary user throughput. Finally, based on the proposed estimation-sensing-throughput tradeoff, we determine suitable estimation and sensing durations that effectively capture the effect of imperfect channel knowledge and subsequently enhance the achievable secondary user throughput. [less ▲]

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See detailMMSE Filtering Performance of DH-AF Massive MIMO Relay Systems with Residual Transceiver Impairments
Papazafeiropoulos, Anastasios; Sharma, Shree Krishna UL; Chatzinotas, Symeon UL

in Proceedings of IEEE ICC 2016 (2016, May)

The emerging requirements of the fifth generation (5G) wireless communications are high spectral efficiency, low latency, and ubiquitous coverage. In this direction, Dual-Hop (DH) Amplify-and-Forward (AF ... [more ▼]

The emerging requirements of the fifth generation (5G) wireless communications are high spectral efficiency, low latency, and ubiquitous coverage. In this direction, Dual-Hop (DH) Amplify-and-Forward (AF) relaying has been widely investigated due to its simplicity, low implementation complexity and low transmission delay. However, most existing works assume ideal transceiver hardware which is impractical. In practice, a cost-efficient wireless transceiver has to combat the effects of several inevitable impairments such as high power amplifier nonlinearities, In-phase/Quadrature-phase (I/Q)-imbalance, and oscillator phase noise, which can be only partially compensated using calibration algorithms. In this direction, this paper analyzes the Minimum Mean Square Error (MMSE) filtering performance of a DH-AF Multiple-Input-Multiple-Output (MIMO) wireless system considering the effects of the residual additive impairments at the transmitter and receiver of both hops. Using free probability principles, the MMSE filtering performance of the considered system is studied and a tight lower bound is proposed by taking the effects of residual additive transceiver impairments into account. Our numerical results show that the MMSE filtering performance of the DH-AF massive MIMO relay system significantly degrades and results to saturation in the presence of residual additive transceiver impairments. [less ▲]

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See detailExperimental Study of an Underlay Cognitive Radio System: Model Validation and Demonstration
Becker, Hanna; Kaushik, Ankit; Sharma, Shree Krishna UL et al

in Proceedings of CROWNCOM 2016 (2016, May)

Cognitive radio is one of the potential contenders that address the problem of spectrum scarcity by making e efficient use of the currently allocated spectrum below 6 GHz. A secondary access to the ... [more ▼]

Cognitive radio is one of the potential contenders that address the problem of spectrum scarcity by making e efficient use of the currently allocated spectrum below 6 GHz. A secondary access to the licensed spectrum is only possible, if the cognitive radio systems restrict the interference to the primary systems. However, the performance analysis of such a cognitive radio system is a challenging task. Currently, performance evaluation of underlay systems is limited to theoretical analysis. Most of the existing theoretical investigations make certain assumptions in order to sustain analytical tractability, which could be unrealistic from the deployment perspective. Motivated by this fact, in this work, we validate the performance of an underlay system by means of laboratory measurements, and consequently propose a hardware demonstrator of such a system. Moreover, we present a graphical user interface to provide insights to the working of the proposed demonstrator and highlight the main issues faced during this experimental study. [less ▲]

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See detailSuperimposed Training based Estimation of Sparse MIMO Channels for Emerging Wireless Networks
Mansoor, Babar; Nawaz, Syed Junaid; Amin, Bilal et al

in Proceedings of ICT 2016 (2016, May)

Multiple-input multiple-output (MIMO) systems constitute an important part of todays wireless communication standards and these systems are expected to take a fundamental role in both the access and ... [more ▼]

Multiple-input multiple-output (MIMO) systems constitute an important part of todays wireless communication standards and these systems are expected to take a fundamental role in both the access and backhaul sides of the emerging wireless cellular networks. Recently, reported measurement campaigns have established that various outdoor radio propagation environments exhibit sparsely structured channel impulse response (CIR). We propose a novel superimposed training (SiT) based up-link channels’ estimation technique for multipath sparse MIMO communication channels using a matching pursuit (MP) algorithm; the proposed technique is herein named as superimposed matching pursuit (SI-MP). Subsequently, we evaluate the performance of the proposed technique in terms of mean-square error (MSE) and bit-error-rate (BER), and provide its comparison with that of the notable first order statistics based superimposed least squares (SI-LS) estimation. It is established that the proposed SI-MP provides an improvement of about 2dB in the MSE at signal-to-noise ratio (SNR) of 12dB as compared to SI-LS, for channel sparsity level of 21.5%. For BER = 10^−2, the proposed SI-MP compared to SI-LS offers a gain of about 3dB in the SNR. Moreover, our results demonstrate that an increase in the channel sparsity further enhances the performance gain [less ▲]

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See detailEffect of Primary User Traffic on Largest Eigenvalue Based Spectrum Sensing Technique
Dhakal, Pawan; Sharma, Shree Krishna UL; Chatzinotas, Symeon UL et al

in Proceedings of International Conference on Cognitive Radio Oriented Wireless Networks (CROWNCOM) (2016, May)

In this paper, the effect of primary user (PU) traffic on the performance of largest eigenvalue based spectrum sensing technique (Roy’s Largest Root Test (RLRT)) is investigated. A simple and realistic ... [more ▼]

In this paper, the effect of primary user (PU) traffic on the performance of largest eigenvalue based spectrum sensing technique (Roy’s Largest Root Test (RLRT)) is investigated. A simple and realistic discrete time modeling of PU traffic is considered which is only based on the discrete time distribution of PU free and busy periods. Furthermore, in order to analyze the effect of PU traffic on the detection performance, analytical expressions for the probability density functions of the decision statistic are derived and validated by Monte-Carlo simulations. Numerical results demonstrate that the sensing performance of RLRT is no more monotonically increasing with the length of the sensing duration and also with SNR which contrasts with the common property of the spectrum sensing techniques under known PU traffic scenario. Furthermore, it is shown that the performance gain due to the multiple antennas in the sensing unit is significantly suppressed by the effect of the PU traffic when the frequency of the PU traffic transitions is higher. [less ▲]

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See detailOn the Error Performance Bound of Ordered Statistics Decoding of Linear Block Codes
Dhakal, Pawan; Garello, Roberto; Sharma, Shree Krishna UL et al

in Proceedings of International Conference on Communications (ICC) (2016, May)

In this paper, a novel simplified statistical approach to evaluate the error performance bound of Ordered Statistics Decoding (OSD) of Linear Block Codes (LBC) is investigated. First, we propose a novel ... [more ▼]

In this paper, a novel simplified statistical approach to evaluate the error performance bound of Ordered Statistics Decoding (OSD) of Linear Block Codes (LBC) is investigated. First, we propose a novel statistic which depicts the number of errors contained in the ordered received noisy codeword. Then, simplified expressions for the probability mass function and cumulative distribution function are derived exploiting the implicit statistical independence property of the samples of the received noisy codeword before reordering. Second, we incorporate the properties of this new statistic to derive the simplified error performance bound of the OSD algorithm for all order−I reprocessing. Finally, with the proposed approach, we obtain computationally simpler error performance bounds of the OSD than those proposed in literature for all length LBCs. [less ▲]

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See detailPerformance Analysis of Hybrid Cognitive Radio Systems with Imperfect Channel Knowledge
Kaushik, Ankit; Sharma, Shree Krishna UL; Chatzinotas, Symeon UL et al

in Proceedings of International Conference on Communications (ICC) (2016, May)

In this paper, we study the performance of hybrid cognitive radio systems that combine the benefits of interweave and underlay systems by employing a spectrum sensing and a power control mechanism at the ... [more ▼]

In this paper, we study the performance of hybrid cognitive radio systems that combine the benefits of interweave and underlay systems by employing a spectrum sensing and a power control mechanism at the Secondary Transmitter (ST). Existing baseline models considered for performance analysis assume perfect knowledge of the involved channels at the ST, however, such situations hardly exist in practical deployments. Motivated by this fact, we propose a novel approach that incorporates channel estimation at the ST, and consequently characterizes the performance of Hybrid Systems (HSs) under realistic scenarios. To capture the impact of imperfect channel knowledge, we propose outage constraints on the detection probability at the ST and on the interference power received at the primary receiver. Our analysis reveals that the baseline model overestimates the performance of the HS in terms of achievable secondary user throughput. Finally, based on the proposed estimation-sensing-throughput tradeoff, we determine suitable estimation and sensing durations that effectively capture the effect of imperfect channel knowledge and subsequently enhance the achievable secondary user throughput. [less ▲]

Detailed reference viewed: 119 (6 UL)