ABSTRACT Lattice Reduction (LR) is a promising technique to improve the performance of linear MIM... more ABSTRACT Lattice Reduction (LR) is a promising technique to improve the performance of linear MIMO detectors. This paper proposes a Hybrid LR algorithm (HLR), which is a scalable LR algorithm. HLR is specifically designed and optimised to exploit ILP and DLP ...
We present the first implementation of a distributed beam-forming algorithm for interference miti... more We present the first implementation of a distributed beam-forming algorithm for interference mitigation on an SDR baseband processor. Co-channel interference (CCI) is becoming a major source of impairments in wireless communications and distributed beamforming is a promising technique to mitigate its negative impact. However, such schemes are challenging to implement in practical scenarios due to their complexity and synchronization requirements. In this paper, we report on implementation of a suboptimal, yet efficient, beamforming scheme for CCI mitigation and present the complexity modeling and algorithm transformations for achieving numerically stability. We also present the fixed-point quantization and the proper mapping on a parallel programmable baseband architecture aimed for software-defined radio (SDR). We optimize this algorithm for a coarse grained reconfigurable array (CGRA) processor and evaluate it in the context of the LTE standard.
... Institute for BroadBand Technology, Gent-Ledeberg B-9050, Belgium) (3Department of Electrical... more ... Institute for BroadBand Technology, Gent-Ledeberg B-9050, Belgium) (3Department of Electrical Engineering, KULeuven, ESAT/INSYS, Belgium) E-mail: Carolina.Blanch@imec ... This way, forForeman and target bit rates of 2 Mbps or 1 Mbps, no quality degradation is perceived ...
Abstract Thanks to recent advances in wireless technology, a broad range of standards are curren... more Abstract Thanks to recent advances in wireless technology, a broad range of standards are currently emerging. Interoperabil-ity and coexistence between these heterogeneous networks are becoming key issues, which require new adaptation strategies to avoid harmful ...
—Advances in low-power and low-cost sensor networks have led to solutions mature enough for use i... more —Advances in low-power and low-cost sensor networks have led to solutions mature enough for use in a broad range of applications varying from health monitoring to building surveillance. The development of those applications has been stimulated by the finalization of the IEEE 802.15.4 standard, which defines the medium access control (MAC) and physical layer for sensor networks. One of the MAC schemes proposed is slotted Carrier Sense Multiple Access with Collision Avoidance (CSMA/CA), and this paper analyzes whether this scheme meets the design constraints of those low-power and low-cost sensor networks. The paper provides a detailed analytical evaluation of its performance in a star topology network, for uplink and acknowledged uplink traffic. Both saturated and unsaturated periodic traffic scenarios are considered. The form of the analysis is similar to that of Bianchi for IEEE 802.11 DCF only in the use of a per user Markov model to capture the state of each user at each moment in time. The key assumptions to enable this important simplification and the coupling of the per user Markov models are however different, as a result of the very different designs of the 802.15.4 and 802.11 carrier sensing mechanisms. The performance predicted by the analytical model is very close to that obtained by simulation. Throughput and energy consumption analysis is then performed by using the model for a range of scenarios. Some design guidelines are derived to set the 802.15.4 parameters as function of the network requirements.
ABSTRACT We adopt a machine learning approach towards the problem of identifying wireless systems... more ABSTRACT We adopt a machine learning approach towards the problem of identifying wireless systems present in a dynamic radio environment with heterogeneous usage. To classify the wireless systems, we utilize two features that typify spectrum use-center frequency and the frequency spread-and cluster the measurement data in this space. Since the systems are unknown prior to clustering, we use an unsupervised clustering method that uses the Chinese restaurant process implemented using Gibbs sampling. The system identification is divided into two parts: training and online classification. In the training phase, we assign wireless systems present in the surrounding to the clusters while the online classification uses this trained data to perform classification. By means of an extensive measurement campaign, we show that the proposed machine learning process achieves up to 90% correctness in classifying the wireless systems considered here.
ABSTRACT Lattice Reduction (LR) is a promising technique to improve the performance of linear MIM... more ABSTRACT Lattice Reduction (LR) is a promising technique to improve the performance of linear MIMO detectors. This paper proposes a Hybrid LR algorithm (HLR), which is a scalable LR algorithm. HLR is specifically designed and optimised to exploit ILP and DLP ...
We present the first implementation of a distributed beam-forming algorithm for interference miti... more We present the first implementation of a distributed beam-forming algorithm for interference mitigation on an SDR baseband processor. Co-channel interference (CCI) is becoming a major source of impairments in wireless communications and distributed beamforming is a promising technique to mitigate its negative impact. However, such schemes are challenging to implement in practical scenarios due to their complexity and synchronization requirements. In this paper, we report on implementation of a suboptimal, yet efficient, beamforming scheme for CCI mitigation and present the complexity modeling and algorithm transformations for achieving numerically stability. We also present the fixed-point quantization and the proper mapping on a parallel programmable baseband architecture aimed for software-defined radio (SDR). We optimize this algorithm for a coarse grained reconfigurable array (CGRA) processor and evaluate it in the context of the LTE standard.
... Institute for BroadBand Technology, Gent-Ledeberg B-9050, Belgium) (3Department of Electrical... more ... Institute for BroadBand Technology, Gent-Ledeberg B-9050, Belgium) (3Department of Electrical Engineering, KULeuven, ESAT/INSYS, Belgium) E-mail: Carolina.Blanch@imec ... This way, forForeman and target bit rates of 2 Mbps or 1 Mbps, no quality degradation is perceived ...
Abstract Thanks to recent advances in wireless technology, a broad range of standards are curren... more Abstract Thanks to recent advances in wireless technology, a broad range of standards are currently emerging. Interoperabil-ity and coexistence between these heterogeneous networks are becoming key issues, which require new adaptation strategies to avoid harmful ...
—Advances in low-power and low-cost sensor networks have led to solutions mature enough for use i... more —Advances in low-power and low-cost sensor networks have led to solutions mature enough for use in a broad range of applications varying from health monitoring to building surveillance. The development of those applications has been stimulated by the finalization of the IEEE 802.15.4 standard, which defines the medium access control (MAC) and physical layer for sensor networks. One of the MAC schemes proposed is slotted Carrier Sense Multiple Access with Collision Avoidance (CSMA/CA), and this paper analyzes whether this scheme meets the design constraints of those low-power and low-cost sensor networks. The paper provides a detailed analytical evaluation of its performance in a star topology network, for uplink and acknowledged uplink traffic. Both saturated and unsaturated periodic traffic scenarios are considered. The form of the analysis is similar to that of Bianchi for IEEE 802.11 DCF only in the use of a per user Markov model to capture the state of each user at each moment in time. The key assumptions to enable this important simplification and the coupling of the per user Markov models are however different, as a result of the very different designs of the 802.15.4 and 802.11 carrier sensing mechanisms. The performance predicted by the analytical model is very close to that obtained by simulation. Throughput and energy consumption analysis is then performed by using the model for a range of scenarios. Some design guidelines are derived to set the 802.15.4 parameters as function of the network requirements.
ABSTRACT We adopt a machine learning approach towards the problem of identifying wireless systems... more ABSTRACT We adopt a machine learning approach towards the problem of identifying wireless systems present in a dynamic radio environment with heterogeneous usage. To classify the wireless systems, we utilize two features that typify spectrum use-center frequency and the frequency spread-and cluster the measurement data in this space. Since the systems are unknown prior to clustering, we use an unsupervised clustering method that uses the Chinese restaurant process implemented using Gibbs sampling. The system identification is divided into two parts: training and online classification. In the training phase, we assign wireless systems present in the surrounding to the clusters while the online classification uses this trained data to perform classification. By means of an extensive measurement campaign, we show that the proposed machine learning process achieves up to 90% correctness in classifying the wireless systems considered here.
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Papers by Sofie Pollin