| 1. |
- Lioliou, Panagiota, 1982, et al.
(author)
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Self-Interference Suppression in Full-Duplex MIMO Relays
- 2010
-
In: 44th Asilomar Conference on Signals, Systems and Computers. - 1058-6393. - 9781424497218 ; , s. 658-662
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Conference paper (peer-reviewed)abstract
- Full-duplex relays can provide cost-effective cover-age extension and throughput enhancement. However, the main limiting factor is the resulting self-interference signal which deteriorates the relay performance. In this paper, we propose a novel technique for self-interference suppression in full-duplex Multiple-Input Multiple-Output (MIMO) relays. The relay employs transmit and receive weight filters for suppressing the self-interference signal. Unlike existing techniques that are based on zero forcing of self-interference, we aim at maximizing the ratio between the power of the useful signal to the self-interference power at the relay reception and transmission. Our simulation results show that the proposed algorithm outperforms the existing schemes since it can suppress interference substantially with less impact on the useful signal.
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| 2. |
- Seifi, Nima, 1981, et al.
(author)
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Coordinated Single-Cell vs Multi-Cell Transmission with Limited-Capacity Backhaul
- 2010
-
In: IEEE Asilomar Conf. on Signals, Systems, and Computers, Pacific Grove, CA, Nov. 2010. - 1058-6393. - 9781424497218 ; , s. 1217-1221
-
Conference paper (peer-reviewed)abstract
- Base station coordination is an efficient techniqueto transcend the limits on spectral efficiency imposed by intercellinterference. In this paper, we compare the performance ofdifferent coordination strategies with different amount of channelstate information (CSI) and data sharing among the coordinatingbase stations. We focus on the effect of limited backhaul capacityin a two-cell network. Contrary to the common belief, we showthat coordination strategies with no data and only limited CSIsharing is preferred to those with full data and CSI sharing whenthe backhaul capacity is relatively low and the edge SNR is high.
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| 3. |
- Aabel, Lise, 1992, et al.
(author)
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Distributed Massive MIMO via all-Digital Radio Over Fiber
- 2020
-
In: Conference Record - Asilomar Conference on Signals, Systems and Computers. - 1058-6393. ; 2020-November, s. 319-323
-
Conference paper (peer-reviewed)abstract
- A crucial challenge in the implementation of distributed massive multiple-input multiple-output (MIMO) architectures is to provide phase coherence while, at the same time, limit the complexity of the remote-radio heads (RRHs), which is important for cost-efficient scalability. To address this challenge, we present in this paper a phase-coherent distributed MIMO architecture, based on off-the-shelf, low-cost components. In the proposed architecture, up- and down-conversion are carried out at the central unit (CU). The RRHs are connected to the CU by means of optical fibers carrying oversampled radio-frequency (RF) 1-bit signals. In the downlink, the 1-bit signal is generated via sigma-delta modulation. At the RRH, the RF signal is recovered from the 1-bit signal through a bandpass filter and a power amplifier, and then fed to an antenna. In the uplink, the 1-bit signal is generated by a comparator whose inputs are the low-noise-amplified received RF signal and a suitably designed dither signal. The performance of the proposed architecture is evaluated with satisfactory results both via simulation and measurements from a testbed.
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| 4. |
- Arslan, Mehmet Ali, et al.
(author)
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Partitioning and Mapping Dynamic Dataflow Programs
- 2012
-
In: [Host publication title missing]. - 1058-6393. ; , s. 1452-1456
-
Conference paper (peer-reviewed)abstract
- Partitioning and mapping are important design decisions in exploiting the parallelism of programs that are to be run on systems with multiple processing elements. In this paper we introduce a fast, incremental approach for mapping dynamic dataflow programs to multiprocessor systems. We use causation traces and architecture descriptions as input for the mapping process that devises several heuristics for reaching a short makespan for the given trace. We evaluate our approach by comparing our results to two different lower bounds and another algorithm used often in solving mapping problems: simulated annealing.
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| 5. |
- Atzeni, Italo, et al.
(author)
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Low-Resolution Massive MIMO Under Hardware Power Consumption Constraints
- 2021
-
In: Conference Record - Asilomar Conference on Signals, Systems and Computers. - 1058-6393. - 9781665458283 ; 2021-October
-
Conference paper (peer-reviewed)abstract
- We consider a fully digital massive multipleinput multiple-output architecture with low-resolution analogto-digital/digital-to-analog converters (ADCs/DACs) at the base station (BS) and analyze the performance trade-off between the number of BS antennas, the resolution of the ADCs/DACs, and the bandwidth. Assuming a hardware power consumption constraint, we determine the relationship between these design parameters by using a realistic model for the power consumption of the ADCs/DACs and the radio frequency chains. Considering uplink pilot-aided channel estimation, we build on the Bussgang decomposition to derive tractable expressions for uplink and downlink ergodic achievable sum rates. Numerical results show that the ergodic performance is boosted when many BS antennas with very low resolution (i.e., 2 to 3 bits) are adopted in both the uplink and the downlink.
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| 6. |
- Bencheikh Lehocine, Chouaib, 1993, et al.
(author)
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Sensitivity analysis of beamforming techniques for periodic broadcast V2V communication
- 2021
-
In: Conference Record - Asilomar Conference on Signals, Systems and Computers. - 1058-6393. ; Volume 2021-October, s. 61-66
-
Conference paper (peer-reviewed)abstract
- In this work, we extend the results of two previously proposed transmit beamforming techniques for periodic, broadcast, vehicle-to-vehicle communication with a common fixed broadcast period, to the scenario where vehicular users (VUs) use different, and potentially varying broadcast periods. The two techniques, analog beamforming network (ABN) of phase shifters and antenna switching network (ASN), were previously developed in accordance with a multiple antenna receiver that employs an analog combining network (ACN) of phase shifters. To accommodate the use of multiple broadcast periods, we propose the design of phase shifter parameters of ABN-ACN and ASN-ACN systems using a design period Td. Then, we analytically derive sets of broadcast periods that sustain optimality, in the sense that the sum signal-to-noise ratio (SNR) of Kconsecutive packets for any receiving VU is maximized. Next, we provide guidelines on how to set Td to ensure a sufficient granularity of the sets of optimal broadcast periods. Finally, we investigate using numerical computations the effect of certain design choices on the sensitivity of ABN/ASN-ACN systems to small variations of the broadcast period.
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| 7. |
- Bernadó, Laura, et al.
(author)
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Complexity reduction for vehicular channel estimation using the filter-divergence measure
- 2011
-
In: 2010 Conference Record of the Forty Fourth Asilomar Conference on Signals, Systems and Computers. - 9781424497225 - 9781424497218
-
Conference paper (peer-reviewed)abstract
- In vehicular communications systems the channel estimation filter suppresses the additive noise in channel estimates obtained from pilot symbols. Vehicular channels show local stationarity for a finite region in time and frequency, only. Such a process can be divided into consecutive stationarity regions, allowing to calculate a Wiener filter. We analyze the increase of the mean square error (MSE) when using a mismatched Wiener filter calculated for a past stationarity region. The MSE increase of the filter is related to a new metric, the filter divergence directly observable at the receiver side. By accepting an increase of MSE, measured by the filter-divergence, the same filter coefficients can be used for several stationarity regions, allowing computational complexity reduction in a real system.
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| 8. |
- Callebaut, Gilles, et al.
(author)
-
Massive MIMO goes Sub-GHz : Implementation and Experimental Exploration for LPWANs
- 2020
-
In: Conference Record of the 54th Asilomar Conference on Signals, Systems and Computers, ACSSC 2020. - 1058-6393. - 9780738131269 ; 2020-November, s. 1101-1105
-
Conference paper (peer-reviewed)abstract
- Low-Power Wide-Area Networks operating in the unlicensed bands are being deployed to connect a rapidly growing number of Internet-of-Things devices. While the unlicensed sub-GHz band offers favorable propagation for long-range connections, measurements show that the energy consumption of the nodes is still mostly dominated by the wireless transmission affecting their autonomy. We investigate the potential benefits of deploying massive MIMO technology to increase system reliability and at the same time support low-energy devices with good coverage at sub-GHz frequencies. The impact of different antenna configurations and propagation conditions is analyzed. Both actual average experienced array gain and channel hardening are examined. The assessment demonstrates the effect of channel hardening as well as the potential benefits of the experienced array gain. These measurements serve as a first assessment of the channel conditions of massive MIMO at sub-GHz frequencies and are, to the best of our knowledge, the first of its kind.
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| 9. |
- Castaneda, Oscar, et al.
(author)
-
Finite-Alphabet Wiener Filter Precoding for mmWave Massive MU-MIMO Systems
- 2019
-
In: Conference Record - Asilomar Conference on Signals, Systems and Computers. - 1058-6393. ; 2019-November, s. 178-183
-
Conference paper (peer-reviewed)abstract
- Power consumption of multi-user (MU) precoding is a major concern in all-digital massive MU multiple-input multiple-output (MIMO) base-stations with hundreds of antenna elements operating at millimeter-wave (mmWave) frequencies. We propose to replace part of the linear Wiener filter (WF) precoding matrix by a finite-alphabet WF precoding (FAWP) matrix, which enables the use of low-precision hardware that consumes low power and area. To minimize the performance loss of our approach, we present methods that efficiently compute FAWP matrices that best mimic the WF precoder. Our results show that FAWP matrices approach infinite-precision error-rate and error-vector magnitude performance with only 3-bit precoding weights, even when operating in realistic mmWave channels. Hence, FAWP is a promising approach to substantially reduce power consumption and silicon area in all-digital mmWave massive MU-MIMO systems.
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| 10. |
- Castañeda, Oscar, et al.
(author)
-
Hardware-Friendly Two-Stage Spatial Equalization for All-Digital mmWave Massive MU-MIMO
- 2020
-
In: Conference Record - Asilomar Conference on Signals, Systems and Computers. - 1058-6393. ; 2020-November, s. 388-392
-
Conference paper (peer-reviewed)abstract
- Next generation wireless communication systems are expected to combine millimeter-wave communication with massive multi-user multiple-input multiple-output technology. All-digital base-station implementations for such systems need to process high-dimensional data at extremely high rates, which results in excessively high power consumption. In this paper, we propose two-stage spatial equalizers that first reduce the problem dimension by means of a hardware-friendly, low-resolution linear transform followed by spatial equalization on a lower-dimensional signal. We consider adaptive and non-adaptive dimensionality reduction strategies and demonstrate that the proposed two-stage spatial equalizers are able to approach the performance of conventional linear spatial equalizers that directly operate on high-dimensional data, while offering the potential to reduce the power consumption of spatial equalization.
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| 11. |
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| 12. |
- Cedersjö, Gustav, et al.
(author)
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Toward Efficient Execution of Dataflow Actors
- 2012
-
In: [Host publication title missing]. - 1058-6393. ; , s. 1465-1469
-
Conference paper (peer-reviewed)abstract
- Dataflow descriptions are a natural match to application areas such as signal processing, cryptography, networking, image processing, and media coding. This paper addresses the problem of efficiently executing the basic elements of a dataflow program, its actors, written in a language such as MPEG's RVC-CAL. Using actor machines as an execution model for dataflow actors, we devise a metric for measuring the quality of a translation in terms of program size and execution efficiency, and then build, evaluate and compare a number of translators with each other and prior art, using MPEG reference code as a benchmark.
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| 13. |
- Cheng, Sijia, et al.
(author)
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MmWave Massive MIMO Processing in Demanding Environments - An Aircraft Cabin Deployment Study
- 2023
-
In: Conference Record of the 57th Asilomar Conference on Signals, Systems and Computers, ACSSC 2023. - 1058-6393. - 9798350325744 ; , s. 1631-1635
-
Conference paper (peer-reviewed)abstract
- Massive multiple-input multiple-output (MIMO) technology will continue playing an important role in beyond 5G wireless systems. Fully digital beamforming at the millimeter wave (mmWave) spectrum enables applications that require high data rates and low latency. This paper investigates the development and deployment of mmWave massive MIMO systems in an in-flight cabin environment, from both system performance and hardware implementation aspects. Ray-tracing methods with realistic geometry coefficients captured from commercial airplane models are used to represent this in-door dense environment. A hardware-in-the-loop simulator running on the AMD/Xilinx PYNQ FPGA is leveraged to conduct fast design space exploration. The outcomes of our investigation provide insights and guidelines in strategies for implementing and deploying mmWave massive MIMO systems in-flight cabins, for instance, how to place and distribute access points to enhance coverage and serve quality and the appropriate quantization strategy balancing hardware cost and signal processing quality.
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| 14. |
- Choraria, Moulik, et al.
(author)
-
Optimal deception attack on networked vehicular cyber physical systems
- 2019
-
In: Conference Record - Asilomar Conference on Signals, Systems and Computers. - 1058-6393. ; 2019-November, s. 1131-1135
-
Conference paper (peer-reviewed)abstract
- Herein, design of false data injection attack on a distributed cyber-physical system is considered. A stochastic process with linear dynamics and Gaussian noise is measured by multiple agent nodes, each equipped with multiple sensors. The agent nodes form a multi-hop network among themselves. Each agent node computes an estimate of the process by using its sensor observations and messages obtained from neighbouring nodes, via Kalman-consensus filtering. An external attacker, capable of arbitrarily manipulating the sensor observations of some or all agent nodes, injects errors into those sensor observations. The goal of the attacker is to steer the estimates at the agent nodes as close as possible to a pre-specified value, while respecting a constraint on the attack detection probability. To this end, a constrained optimization problem is formulated to find the optimal parameter values of a certain class of linear attacks. The parameters of linear attack are learnt on-line via a combination of stochastic approximation and online stochastic gradient descent. Numerical results demonstrate the efficacy of the attack.
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| 15. |
- Chowdhury, Sohini Roy, et al.
(author)
-
Automated Augmentation with Reinforcement Learning and GANs for Robust Identification of Traffic Signs using Front Camera Images
- 2019
-
In: Conference Record - Asilomar Conference on Signals, Systems and Computers. - 1058-6393. - 9781728143002 ; 2019-November, s. 79-83
-
Conference paper (peer-reviewed)abstract
- Traffic sign identification using camera images from vehicles plays a critical role in autonomous driving and path planning. However, the front camera images can be distorted due to blurriness, lighting variations and vandalism which can lead to degradation of detection performances. As a solution, machine learning models must be trained with data from multiple domains, and collecting and labeling more data in each new domain is time consuming and expensive. In this work, we present an end-to-end framework to augment traffic sign training data using optimal reinforcement learning policies and a variety of Generative Adversarial Network (GAN) models, that can then be used to train traffic sign detector modules. Our automated augmenter enables learning from transformed nightime, poor lighting, and varying degrees of occlusions using the LISA Traffic Sign and BDD-Nexar dataset. The proposed method enables mapping training data from one domain to another, thereby improving traffic sign detection precision/recall from 0.70/0.66 to 0.83/0.71 for nighttime images.
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| 16. |
- Christopoulos, Dimitrios, et al.
(author)
-
Capacity Analysis of Multibeam Joint Decoding over Composite Satellite Channels
- 2011
-
In: Proc. of the 45th Asilomar Conference on Signals, Systems and Computer. - : IEEE Signal Processing Society. - 1058-6393. - 9781467303231
-
Conference paper (peer-reviewed)abstract
- The throughput of current multibeam satellite systemsis limited by self interference. Interference mitigationtechniques have the potential to significantly increase the spectralefficiency of these satellite communication systems. The presentcontribution investigates the ergodic capacity of the return linkof a multibeam satellite system, where full frequency reuse is employedand user signals are jointly processed at the gateway. Theproposed model incorporates correlated satellite antennas overRician channels which represent some inherent characteristics ofsatellite communications. Additionally, the effects of shadowingcaused by user mobility, are modeled via the lognormal distribution.Hence, a composite Rician/lognormal fading channel withfully correlated receive antennas is considered. For this channel, anew lower bound on the ergodic capacity is analytically deducedand verified through simulations.
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| 17. |
- Chung, Min Keun, et al.
(author)
-
Millimeter-Wave Massive MIMO Testbed with Hybrid Beamforming
- 2020
-
In: Conference Record of the 54th Asilomar Conference on Signals, Systems and Computers, ACSSC 2020. - 1058-6393. - 9780738131269 ; 2020-November, s. 309-313
-
Conference paper (peer-reviewed)abstract
- Massive multiple-input multiple-out (MIMO) technology is vital in millimeter-wave (mmWave) bands to obtain large array gains. However, there are practical challenges, such as high hardware cost and power consumption in such systems. A promising solution to these problems is to adopt a hybrid beamforming architecture. This architecture has a much lower number of transceiver (TRx) chains than the total antenna number, resulting in cost- and energy-efficient systems. In this paper, we present a real-time mmWave (28GHz) massive MIMO testbed with hybrid beamforming. This testbed has a 64-antenna/16-TRx unit for beam-selection, which can be expanded to larger array sizes in a modular way. For testing everything from baseband processing algorithms to scheduling and beam-selection in real propagation environments, we extend the capability of an existing 100-antenna/100-TRx massive MIMO testbed (below 6GHz), built upon software-defined radio technology, to a flexible mmWave massive MIMO system.
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| 18. |
- Destino, G., et al.
(author)
-
Performance Analysis of Hybrid 5G-GNSS Localization
- 2018
-
In: Conference Record - Asilomar Conference on Signals, Systems and Computers. - 1058-6393. ; 2018-October, s. 8-12
-
Conference paper (peer-reviewed)abstract
- We consider a novel positioning solution combining millimeter wave (mmW) 5G and Global Navigation Satellite System (GNSS) technologies. The study is carried out theoretically by deriving the Fisher Information Matrix (FIM) of a combined 5G-GNSS positioning system and, subsequently, the position, rotation and clock-bias error lower bounds. We pursue a two-step approach, namely, computing first the FIM for the channel parameters, and then transforming it into the FIM of the position, rotation and clock-bias. The analysis shows advantages of the hybrid positioning in terms of i) localization accuracy, ii) coverage, iii) precise rotation estimation and iv) clock-error estimation. In other words, we demonstrate that a tight coupling of the two technologies can provide mutual benefits.
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| 19. |
- Di Taranto, Rocco, 1977, et al.
(author)
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Simultaneous Routing and Power Allocation using Location Information
- 2013
-
In: Conference Record - Asilomar Conference on Signals, Systems and Computers. - 1058-6393. - 9781479923908 ; , s. 1700-1704
-
Conference paper (peer-reviewed)abstract
- To guarantee optimal performance of wireless networks,simultaneous optimization of routing and resource allocationis needed. Optimal routing of data depends on the linkcapacities which, in turn, are determined by the allocation of communication resources to the links. Simultaneous routing and resource allocation (SRRA) problems have been studied under the assumption that (global) channel state information (CSI) is collected at a central node. This is a drawback as SRRA depends on channels between all pairs of nodes in the network, thus leading to poor scalability of the CSI-based approach. In this paper, we first investigate to what extent it is possible to rely solely on location information (i.e., position of nodes) when solving the SRRA problem. We also propose a distributed heuristic based onwhich nodes can locally adjust their rate based on the local CSI. Our numerical results show that the proposed heuristic achieves near-optimal flow in the network under different shadowing conditions.
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| 20. |
- Ettefagh, Yasaman, 1989, et al.
(author)
-
All-Digital Massive MIMO Uplink and Downlink Rates under a Fronthaul Constraint
- 2019
-
In: Conference Record - Asilomar Conference on Signals, Systems and Computers. - 1058-6393. - 9781728143002 ; 2019-November, s. 416-420
-
Conference paper (peer-reviewed)abstract
- We characterize the rate achievable in a bidirectional quasi-static link where several user equipments communicate with a massive multiple-input multiple-output base station (BS). In the considered setup, the BS operates in full-digital mode, the physical size of the antenna array is limited, and there exists a rate constraint on the fronthaul interface connecting the (possibly remote) radio head to the digital baseband processing unit. Our analysis enables us to determine the optimal resolution of the analog-todigital and digital-to-analog converters as well as the optimal number of active antenna elements to be used in order to maximize the transmission rate on the bidirectional link, for a given constraint on the outage probability and on the fronthaul rate. We investigate both the case in which perfect channel-state information is available, and the case in which channel-state information is acquired through pilot transmission, and is, hence, imperfect. For the second case, we present a novel rate expression that relies on the generalized mutual-information framework.
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| 21. |
- Etzlinger, B., et al.
(author)
-
Cooperative Simultaneous Localization and Synchronization: A Distributed Hybrid Message Passing Algorithm
- 2013
-
In: Conference Record - Asilomar Conference on Signals, Systems and Computers. - 1058-6393. - 9781479923908 ; , s. 1978-1982
-
Conference paper (peer-reviewed)abstract
- Cooperative sensor self-localization (CSL) in wireless networks usually requires the nodes to be equipped with specific ranging hardware including ultra-wideband or ultrasonic distance sensors. Such designs are not suitable for application in low-cost, low-power sensor networks. Here, we demonstrate how low-cost, low-power, asynchronous sensor nodes can be used to perform CSL (and, simultaneously, distributed synchronization) by means of time-stamped communication without additional ranging hardware. Our method combines a belief propagation message passing algorithm for cooperative simultaneous localization and synchronization (CoSLAS) with a MAC-layer time stamping scheme.We validate the models underlying the CoSLAS algorithm by means of measurements, and we demonstrate that the localization accuracy achieved by our hardware implementation is far better than that corresponding to the time resolution and measurement errors of the hardware.
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| 22. |
- Fedorov, Aleksei, et al.
(author)
-
Implementation of spatially consistent channel models for real-time full stack C-ITS V2X simulations
- 2021
-
In: 55th Asilomar Conference on Signals, Systems and Computers, ACSSC 2021. - 1058-6393. - 9781665458283 ; 2021-October, s. 67-71
-
Conference paper (peer-reviewed)abstract
- Vehicle-to-everything (V2X) wireless communication is expected to play a key role in enabling complex Advanced Driving Assistance Applications, including the support of emerging autonomous vehicles. The development of V2X applications, especially safety-related, requires rigorous verification. Field trials, though, have to be supplemented with less expensive and more repeatable methods. Thorough V2X modeling could be an efficient approach to boost V2X development. However, to be helpful, V2X modeling has to be realistic and properly capture the signal propagation in a complex V2X environment. To this end, Geometry Based Stochastic Models (GSCM) have been derived to account for the influence of the environment as well as small yet critical details, where we typically lack information about their physical and geometrical properties. In this paper, we present an implementation of a GSCM in the Unity3D game engine. Due to extensive signal path search in a 3D environment with ray-tracing, the GSCM computation has to be further optimized to enable real-time V2X simulations. Thus, we also propose the approach for GSCM computation optimization and explain the practicalities of its implementation. The results show that optimization can accelerate the simulation framework up to a few thousand times without losing the precision in modeling channel characteristics.
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| 23. |
- Ferreira, Lucas, et al.
(author)
-
Energy-Efficient Application-Specific Instruction-Set Processor for Feature Extraction in Smart Vision Systems
- 2021
-
In: Conference Record - Asilomar Conference on Signals, Systems and Computers. - 1058-6393. - 9781665458283 ; 2021-October, s. 324-328
-
Conference paper (peer-reviewed)abstract
- Smart vision sensor systems enable many computer vision applications such as autonomous drones and wearable devices. These battery-powered gadgets have very stringent power consumption requirements. Close-to-sensor feature extraction compressing the full image into descriptive keypoints, is crucial as it allows for several design optimizations. First, the amount of necessary on-chip memory can be lessened. Second, the volume of data that needs to be exchanged between nodes in Internet of Things (IoT) applications can also be reduced. This work explores the usage of an Application Specific Instruction Set Processor (ASIP) tailored to perform energy-efficient feature extraction in real-time. The ASIP features a Very Long Instruction Word (VLIW) central core comprising one RV32I RISCV and three vector slots. The on-chip memory sub-system implements parallel multi-bank memories with near-memory data shuffling to enable single-cycle multi-pattern vector access. As a case study, Oriented FAST and Rotated BRIEF (ORB) is used to evaluate the proposed architecture. We show that the architecture supports VGA-resolution images at 140 Frames-Per-Second (FPS), for one scale, reducing the number of memory accesses by 2 orders of magnitude comparing to other embedded general-purpose architectures.
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| 24. |
- Gao, Xiang, et al.
(author)
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Massive MIMO channels - measurements and models
- 2013
-
In: 2013 Asilomar Conference on Signals, Systems and Computers. - 1058-6393. - 9781479923908 ; , s. 280-284
-
Conference paper (peer-reviewed)abstract
- Spatial multiplexing using Massive MIMO has been shown to have very promising properties, including large gains in spectral efficiency and several orders of magnitude lower transmit power, as compared to today's access schemes. The properties of massive MIMO have been studied mostly for theoretical channels with independent and identically distributed (i.i.d.) complex Gaussian coefficients. To efficiently evaluate massive MIMO in more realistic scenarios, we need channel models that capture important massive MIMO channel characteristics. We pursue this by analyzing measurement data from a measurement campaign in the 2.6 GHz frequency range, using a physically large array with 128 elements. Key propagation characteristics are identified from the measurements. We use the cluster-based COST 2100 MIMO channel model as a basis, and propose an extension to include those important propagation properties for massive MIMO. Statistical models of the total number of clusters, their visibility regions and visibility gains at the base station side are found based on the measurement data.
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| 25. |
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| 26. |
- Graell I Amat, Alexandre, 1976, et al.
(author)
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Coded Slotted Aloha with Stopping Set Resolution: A Group Testing Approach
- 2022
-
In: Conference Record - Asilomar Conference on Signals, Systems and Computers. - 1058-6393. ; 2022-October, s. 677-681
-
Conference paper (peer-reviewed)abstract
- In this work, we explore the use of group testing techniques to steer a collision resolution phase in the context of coded slotted Aloha protocols. The problem can be defined as the discovery of stopping sets based on the residual collision pattern after successive interference cancellation decoding. We show how the application of the simple combinatorial orthogonal matching pursuit algorithm is sufficient to resolve a large number of the collisions that hinder the success of the iterative interference cancellation process. We highlight the design choices that have to be addressed to benefit from the proposed approach. Finally, we outline a few interesting directions for future developments.
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| 27. |
- Gruian, Flavius
(author)
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Runtime Voltage/Frequency Scaling for Energy-Aware Streaming Applications
- 2012
-
In: Proceedings of the Forty Sixth Asilomar Conference on Signals, Systems and Computers (ASILOMAR). - 1058-6393. - 9781467350501 - 9781467350518 ; , s. 1439-1443
-
Conference paper (peer-reviewed)abstract
- Power and energy consumption, today essential in all types of systems, can be reduced by scaling the voltage/frequency at runtime and/or powering down idle components. Efficient management requires not only pertinent decisions, but also early access to workload information, as well as domain specific solutions. This paper focuses on runtime energy management for streaming applications running on multiprocessor platforms with dynamic voltage/frequency (speed) scaling capabilities. Our energy management occurs at processor level, and employs a number of orthogonal techniques based on hints gathered from load history, buffer pressure and future workload estimates. The manager operates both through speed adjustments and priorities. A preliminary evaluation based on a high-level simulation of an MPEG-4 SP decoder, shows that a combination of specific and generic techniques is the closest to an ideal energy lower bound.
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| 28. |
- Hammarberg, Peter, et al.
(author)
-
On the performance of iterative receivers for interfering MIMO-OFDM systems in measured channels
- 2008
-
In: 42nd Asilomar Conference on Signals, Systems and Computers. - 1058-6393. - 9781424429400 ; , s. 141-145
-
Conference paper (peer-reviewed)abstract
- This paper investigates the gains harvested through base station cooperation in the up-link for a multi-user (MU) Multiple-Input Multiple-Output Orthogonal Frequency Division Multiplexing (MIMO-OFDM) system, operating in a real indoor environment. The base stations perform joint detection using an iterative receiver that carries out multi-user detection and channel estimation via soft information from the single-user decoders. Performance evaluation is carried out using real channels from an indoor dynamic dual MIMO link measurement campaign. The measured scenario represent a real life situation where two users communicate with two base stations, each with two antennas, in an environment resembling a shopping mall or an airport terminal. System performance is evaluated in terms of both Bit-Error Rate (BER) vs. Signal-to-Interference Ratio (SIR) and Cumulative Distribution Functions (CDF) for the instantaneous BER. Also, the impact of using soft information in the channel estimation is analyzed.
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| 29. |
- Herzfeld, Jonas, et al.
(author)
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Collision Avoidance by Utilizing Dynamic Road Friction Information
- 2020
-
In: Conference Record - Asilomar Conference on Signals, Systems and Computers. - 1058-6393. ; 2020-November, s. 1425-1429
-
Conference paper (peer-reviewed)abstract
- Advanced driver assistance systems require an autonomous emergency braking (AEB) system that considers varying tire-to-road friction conditions to estimate minimum emergency braking distance for collision avoidance. Conventional AEB systems, either do not consider the friction at all or assume constant friction, even though the actual road friction profile is dynamic. Ignoring the dynamic friction conditions leads to inefficient operation under slippery road conditions. Therefore, in this work, we present a novel AEB system that exploits friction information ahead of the ego-vehicle that is predicted using on-board vehicle sensors as well with cloud services. The proposed algorithm utilizes the predicted dynamic friction profile and calculates the last braking point to prevent a collision. We implement a simplified vehicle model that enables fast online computations to evaluate the braking distance. Next, the braking sequence is initiated by an anti-lock braking system with slip control. The performance of the proposed algorithm and controller are simulated and evaluated in terms of the braking distance metric that evaluates the relative distance between the ego-vehicle and the threat vehicle at a standstill. The proposed system achieves an improvement of up to 95.8% for varying friction profiles when compared to braking error obtained by constant friction profiles. Furthermore, the proposed system is capable of preventing collisions in all experimental test, thus making it suitable for designing active safety functionalities.
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| 30. |
- Jacobsson, Sven, 1990, et al.
(author)
-
Massive MU-MIMO-OFDM Uplink with Hardware Impairments: Modeling and Analysis
- 2018
-
In: Conference Record - Asilomar Conference on Signals, Systems and Computers. - 1058-6393. ; 2018-October, s. 1829-1835
-
Conference paper (peer-reviewed)abstract
- © 2018 IEEE. We study the impact of hardware impairments at the base station (BS) of an orthogonal frequency-division multiplexing (OFDM)-based massive multiuser (MU) multiple-input multiple-output (MIMO) uplink system. We leverage Bussgang's theorem to develop accurate models for the distortions caused by nonlinear low-noise amplifiers, local oscillators with phase noise, and oversampling finite-resolution analog-to-digital converters. By combining the individual effects of these hardware models, we obtain a composite model for the BS-side distortion caused by nonideal hardware that takes into account its inherent correlation in time, frequency, and across antennas. We use this composite model to analyze the impact of BS-side hardware impairments on the performance of realistic massive MU-MIMO-OFDM uplink systems.
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| 31. |
- Jacobsson, Sven, 1990, et al.
(author)
-
Nonlinear 1-bit precoding for massive MU-MIMO with higher-order modulation
- 2017
-
In: Conference Record - Asilomar Conference on Signals, Systems and Computers. - 1058-6393. ; , s. 763-767
-
Conference paper (peer-reviewed)abstract
- Massive multi-user (MU) multiple-input multiple-output (MIMO) is widely believed to be a core technology for the upcoming fifth-generation (5G) wireless communication standards. The use of low-precision digital-to-analog converters (DACs) in MU-MIMO base stations is of interest because it reduces the power consumption, system costs, and raw baseband data rates. In this paper, we develop novel algorithms for downlink precoding in massive MU-MIMO systems with 1-bit DACs that support higher-order modulation schemes such as 8-PSK or 16-QAM. Specifically, we present low-complexity nonlinear precoding algorithms that achieve low error rates when combined with blind or training-based channel-estimation algorithms at the user equipment. These results are in stark contrast to linear-quantized precoding algorithms, which suffer from a high error floor if used with high-order modulation schemes and 1-bit DACs
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| 32. |
- Jacobsson, Sven, 1990, et al.
(author)
-
On Out-of-Band Emissions of Quantized Precoding in Massive MU-MIMO-OFDM
- 2017
-
In: Conference Record of the Asilomar Conference on Signals Systems and Computers. - 1058-6393. - 9781538618233 ; 2017-October, s. 21-26
-
Conference paper (peer-reviewed)abstract
- We analyze out-of-band (OOB) emissions in the massive multi-user (MU) multiple-input multiple-output (MIMO) downlink. We focus on systems in which the base station (BS) is equipped with low-resolution digital-to-analog converters (DACs) and orthogonal frequency-division multiplexing (OFDM) is used to communicate to the user equipments (UEs) over frequency- selective channels. We demonstrate that analog filtering in combination with simple frequency-domain digital predistortion (DPD) at the BS enables a significant reduction of OOB emissions, but degrades the signal-to-interference-noise-and-distortion ratio (SINDR) at the UEs and increases the peak-to-average power ratio (PAR) at the BS. We use Bussgang’s theorem to characterize the tradeoffs between OOB emissions, SINDR, and PAR, and to study the impact of analog filters and DPD on the error-rate perfor- mance of the massive MU-MIMO-OFDM downlink. Our results show that by carefully tuning the parameters of the analog filters, one can achieve a significant reduction in OOB emissions with only a moderate degradation of error-rate performance and PAR.
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| 33. |
- Janneck, Jörn
(author)
-
A machine model for dataflow actors and its applications
- 2011
-
In: Proceedings of the 45th Annual Asilomar Conference on Signals, Systems, and Computers. - 1058-6393. ; , s. 756-760
-
Conference paper (peer-reviewed)abstract
- In application areas that process stream-like data such as multimedia, networking and DSP, the pipelined concurrent processing is frequently represented as a dataflow network of communicating computational kernels connected by FIFO queues. However, while dataflow is a natural medium for conceptualizing and modeling stream-processing systems, its adoption as a programming methodology has been hindered by an unappealing choice between expres- siveness and efficient implementability—efficient implemen- tation techniques being primarily limited to restricted sub- classes of dataflow programs. The paper presents a simple machine model for a very general class of dataflow programs and shows how it can be used as a foundation for their efficient implementation.
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| 34. |
- Kim, Hyowon, 1987, et al.
(author)
-
5G mmWave Vehicular Tracking
- 2018
-
In: Conference Record - Asilomar Conference on Signals, Systems and Computers. - 1058-6393. ; 2018-October, s. 541-547
-
Conference paper (peer-reviewed)abstract
- Vehicle positioning based on GPS is limited due to multipath and blockage. 5G mmWave signals can provide an attractive complement, as it is possible to estimate the state of a vehicle (position and heading) from transmissions from a single base station. We propose a Bayesian 5G mmWave tracking filter, which explicitly relies on mapping the radio environment. The filter thus solves a novel type of simultaneous localization and mapping problem, which enables estimating not only the vehicle heading and position, but also its clock bias.
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| 35. |
- Kislal, Ahmet Oguz, 1993, et al.
(author)
-
Efficient evaluation of the error probability for pilot-assisted finite-blocklength transmission
- 2022
-
In: Conference Record - Asilomar Conference on Signals, Systems and Computers. - 1058-6393. ; 2022-October, s. 1038-1044
-
Conference paper (peer-reviewed)abstract
- We propose a numerically efficient method for evaluating the random-coding union bound with parameter s on the error probability achievable in the finite-blocklength regime by a pilot-assisted transmission scheme employing Gaussian code-books and operating over a memoryless block-fading channel. Our method relies on the saddlepoint approximation, which, differently from previous results reported for similar scenarios, is performed with respect to the number of fading blocks (a.k.a. diversity branches) spanned by each codeword, instead of the number of channel uses per block. This different approach avoids a costly numerical averaging of the error probability over the realizations of the fading process and of its pilot-based estimate at the receiver and yields a significant reduction of the number of channel realizations required to estimate the error probability via Monte-Carlo simulation. For example, in a single-input single-output scenario, when four or more diversity branches are available, an error probability of 10-4can be estimated accurately using our method by using less than 3000 samples. In contrast, the conventional saddlepoint approach requires around 106samples.
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| 36. |
- Lancho Serrano, Alejandro, 1991, et al.
(author)
-
Finite-Blocklength Approximations for Noncoherent Rayleigh Block-Fading Channels
- 2019
-
In: Conference Record - Asilomar Conference on Signals, Systems and Computers. - 1058-6393. ; 2019, s. 815-819
-
Conference paper (peer-reviewed)abstract
- Several emerging wireless communication services and applications have stringent latency requirements, necessitating the transmission of short packets. To obtain performance benchmarks for short-packet wireless communications, it is crucial to study the maximum coding rate as a function of the blocklength, commonly called finite-blocklength analysis. A finiteblocklength analysis can be performed via nonasymptotic bounds or via refined asymptotic approximations. This paper reviews finite-blocklength approximations for the noncoherent Rayleigh block-fading channel. These approximations have negligible computational cost compared to the nonasymptotic bounds and are shown to be accurate for error probabilities as small as 10^-8 and SNRs down to 0 dB.
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| 37. |
- Lioliou, Panagiota, 1982, et al.
(author)
-
Performance Analysis of Relay Channel Estimation
- 2009
-
In: 43rd Asilomar Conference on Signals, Systems and Computers; Pacific Grove, CA; United States; 1 November 2009 through 4 November 2009. - 1058-6393. - 9781424458271 ; , s. 1533-1537
-
Conference paper (peer-reviewed)abstract
- Amplify-and-Forward (AF) relays can be used to enhance the channel in Multiple-Input-Multiple-Output (MIMO) wireless communication systems. However, optimizing the channel requires Channel State Information (CSI). This paper is concerned with the performance of relay channel estimation. A Least Squares (LS) based algorithm for the estimation of all relevant channel parameters was recently proposed by the authors. It is based on creating different compound channels by varying the gain factors at the relays. From this, the individual links from source to relay and from relay to destination, are revealed using LS. To investigate the algorithm performance, the Cramér-Rao lower Bound (CRB) is computed and compared with the asymptotic covariance of the proposed estimator. Furthermore, we propose and analyze an improved algorithm that is efficient for high Signal-to-Noise Ratio (SNR). Computer simulations demonstrate the performance of the algorithm. The results indicate that the asymptotic expressions are in good agreement with the simulations.
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| 38. |
- Liva, Gianluigi, et al.
(author)
-
Coded Slotted Aloha over the On-Off Fading Channel: Performance Bounds
- 2019
-
In: Conference Record - Asilomar Conference on Signals, Systems and Computers. - 1058-6393. - 9781728143002 ; 2019-November, s. 31-35
-
Conference paper (peer-reviewed)abstract
- The on-off fading channel is used as a proxy to gain insights on the performance of coded slotted Aloha (CSA) access protocols on the block flat fading channel. Bounds on the performance of CSA are developed, which include both the on-off fading effect and multi-packet reception capabilities at the receiver. The bounds apply to the case where a non-vanishing packet loss probability can be tolerated. A comparison of simulation results for actual CSA schemes with the developed bounds is provided.
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| 39. |
- Marti, Gian, et al.
(author)
-
Hybrid Jammer Mitigation for All-Digital mmWave Massive MU-MIMO
- 2021
-
In: Conference Record - Asilomar Conference on Signals, Systems and Computers. - 1058-6393. - 9781665458283 ; 2021-October
-
Conference paper (peer-reviewed)abstract
- Low-resolution analog-to-digital converters (ADCs) simplify the design of millimeter-wave (mmWave) massive multi-user multiple-input multiple-output (MU-MIMO) base-stations, but increase vulnerability to jamming attacks. As a remedy, we propose HERMIT (short for Hybrid jammER MITigation), a method that combines a hardware-friendly adaptive analog transform with a corresponding digital equalizer: The analog transform removes most of the jammer’s energy prior to data conversion; the digital equalizer suppresses jammer residues while detecting the legitimate transmit data. We provide theoretical results that establish the optimal analog transform as a function of the user equipments' and the jammer’s channels. Using simulations with mmWave channel models, we demonstrate the superiority of HERMIT compared both to purely digital jammer mitigation as well as to a recent hybrid method that mitigates jammer interference with a nonadaptive analog transform.
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| 40. |
- Mirza, Usman Mazhar, et al.
(author)
-
High-Level Architecture Modeling and Exploration for Streaming Applications
- 2012
-
In: Proceedings of the Forty Sixth Asilomar Conference on Signals, Systems and Computers (ASILOMAR). - 1058-6393. - 9781467350501 - 9781467350518 ; , s. 1263-1266
-
Conference paper (peer-reviewed)abstract
- Multi and many core platforms are increasingly employed today to cope with the demands of modern multimedia, networking and other similar streaming applications. Selecting the best architecture for a set of such applications is complex, and without coding for each specific system, the choice is made based on designer experience. In this paper we use CAL, a dataflow language for specifying streaming applications, to model both the software and generic hardware platforms. The hardware model is combined with the mapped application in a high-level unified model, which is simulated to obtain performance estimates, intended to give feedback during design space exploration.
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| 41. |
- Mollén, Christopher, et al.
(author)
-
Analysis of nonlinear low-noise amplifiers in massive MIMO base stations
- 2017
-
In: 2017 51st Asilomar Conference on Signals, Systems, and Computers. - 1058-6393. - 9781538618233 - 9781538618240 ; , s. 285-289
-
Conference paper (peer-reviewed)abstract
- Because of the large number of antennas at the base station, the power consumption and cost of the low-noise amplifiers (LNAs) can be substantial. Therefore, we investigate the feasibility of inexpensive, power efficient LNAs, which inherently are less linear. To characterize the nonlinear distortion, we describe the LNAs using a polynomial model, which allows for the derivation of the second-order statistics of the received signal and the distortion. A massive MIMO system that serves one user in line-of-sight is studied. It is shown that the distortion from the LNAs combines coherently and that the SINR of the symbol estimates therefore is limited by the linearity of the LNAs. Furthermore, the impact of a strong transmitter in the adjacent frequency band is investigated. The second-order statistics show how the power from that transmission leaks into the main band and interferes with the symbol estimates.
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| 42. |
- Munari, Andrea, et al.
(author)
-
An Age of Information Characterization of Frameless ALOHA
- 2021
-
In: Conference Record - Asilomar Conference on Signals, Systems and Computers. - 1058-6393. ; 2021-October, s. 1488-1495
-
Conference paper (peer-reviewed)abstract
- We provide a characterization of the peak age of information (AoI) achievable in a random-access system operating according to the frameless ALOHA protocol. Differently from previous studies, our analysis accounts for the fact that the number of terminals contending the channel may vary over time, as a function of the duration of the previous contention period. The exact characterization of the AoI provided in this paper, which is based on a Markovian analysis, reveals the impact of some key protocol parameters such as the maximum length of the contention period, on the average peak AoI. Specifically, we show that setting this parameter so as to maximize the throughput may result in an AoI degradation.
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| 43. |
- Muneer, Sidra, et al.
(author)
-
Handling PA Nonlinearity in Massive MIMO : What are the Tradeoffs between System Capacity and Power Consumption
- 2020
-
In: Conference Record of the 54th Asilomar Conference on Signals, Systems and Computers, ACSSC 2020. - 1058-6393. - 9780738131269 ; 2020-November, s. 974-978
-
Conference paper (peer-reviewed)abstract
- Massive MIMO enables a very high spectral efficiency by spatial multiplexing and opens opportunities to reduce transmit power per antenna. On the other side, it also introduces new challenges in tackling the power amplifier nonlinearity due to the increased number of antennas. The behavior of Out-of-Band radiation from PAs in Massive MIMO is non-trivial depending upon the applied precoding scheme, propagation environment, and how the users are distributed spatially. In this paper, we analyze the in-band and Out-of-Band power distribution in space for a Massive MIMO base station with nonlinear power amplifiers. We also study the tradeoff between amplifier power consumption and system performance (in terms of error vector magnitude at intended receivers) for PAs with different backoff operating levels. The spatial analysis of Out-of-Band under more realistic channel conditions is more reflective of the situation, to determine system emission requirements. The tradeoff between performance and power consumption will provide a basis for future investigations into the design of efficient Massive MIMO systems, taking nonlinearities into account.
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| 44. |
- Muppirisetty, Srikar, 1984, et al.
(author)
-
Robust Link Scheduling with Channel Estimation and Location Information
- 2014
-
In: Conference Record - Asilomar Conference on Signals, Systems and Computers. - 1058-6393.
-
Conference paper (peer-reviewed)abstract
- We study the robust link scheduling problem (RLSP)based on a physical interference model with errors in channelstate information. The objective of RLSP is to find a robust minimum length schedule using spatial time division multiple access. We compare two approaches to RLSP, one using channel gain estimates and the other using location information. In both cases, we formulate the RLSP as a binary integer program and solve it by a classical column generation technique. Our comparison reveals that both approaches yield similar performances, but with different overhead.
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| 45. |
- Ngo, Khac-Hoang, 1992, et al.
(author)
-
Age of Information in Prioritized Random Access
- 2021
-
In: Conference Record - Asilomar Conference on Signals, Systems and Computers. - 1058-6393. - 9781665458283 ; 2021-October
-
Conference paper (peer-reviewed)abstract
- Age of information (AoI) is a performance metric that captures the freshness of status updates. While AoI has been studied thoroughly for point-to-point links, the impact of modern random-access protocols on this metric is still unclear. In this paper, we extend the recent results by Munari to prioritized random access where devices are divided into different classes according to different AoI requirements. We consider the irregular repetition slotted ALOHA protocol and analyze the AoI evolution by means of a Markovian analysis following similar lines as in Munari (2021). We aim to design the protocol to satisfy the AoI requirements for each class while minimizing the power consumption. To this end, we optimize the update probability and the degree distributions of each class, such that the probability that their AoI exceeds a given threshold lies below a given target and the average number of transmitted packets is minimized.
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| 46. |
- Ngo, Khac-Hoang, 1992, et al.
(author)
-
Unsourced Multiple Access for Heterogeneous Traffic Requirements
- 2022
-
In: Conference Record - Asilomar Conference on Signals, Systems and Computers. - 1058-6393. ; 2022-October, s. 687-691
-
Conference paper (peer-reviewed)abstract
- We investigate the coexistence of critical and massive Internet of Things (IoT) services in the context of the unsourced multiple access (UMA) framework, introduced by Polyanskiy (2017). We consider the standard UMA setup in which all users employ a common codebook and the receiver returns an unordered list of codewords. To model the critical IoT service, we assume that the users can also communicate a common alarm message. We further assume that the number of active users in each transmission attempt is random and unknown. We derive a random-coding bound for the Gaussian multiple access channel and demonstrate that orthogonal network slicing enables the two traffic types to coexist with high energy efficiency.
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| 47. |
- Panahi, Ashkan, 1986, et al.
(author)
-
A robust ℓ1 penalized DOA estimator
- 2012
-
In: Conference Record - Asilomar Conference on Signals, Systems and Computers. - 1058-6393. - 9781467350518 ; , s. 2013-2017
-
Conference paper (peer-reviewed)abstract
- The SPS-LASSO has recently been introduced as a solution to the problem of regularization parameter selection in the complex-valued LASSO problem. Still, the dependence on the grid size and the polynomial time of performing convex optimization technique in each iteration, in addition to the deficiencies in the low noise regime, confines its performance for Direction of Arrival (DOA) estimation. This work presents methods to apply LASSO without grid size limitation and with less complexity. As we show by simulations, the proposed methods loose a negligible performance compared to the Maximum Likelihood (ML) estimator, which needs a combinatorial search We also show by simulations that compared to practical implementations of ML, the proposed techniques are less sensitive to the source power difference.
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| 48. |
- Pereira, Andreia, et al.
(author)
-
The Impact of Terminal Mobility on the Performance of a Panel-Based Large Intelligent Surface
- 2020
-
In: Conference Record of the 54th Asilomar Conference on Signals, Systems and Computers, ACSSC 2020. - 1058-6393. - 9780738131269 ; 2020-November, s. 569-573
-
Conference paper (peer-reviewed)abstract
- A Large Intelligent Surface (LIS) is a recently pro-posed concept that relies on the integration of a vast number of antenna-elements over an entire surface able to transmit and/or receive information, especially suitable for high speed indoor communications and massive internet of things (IoT) applications. In this paper, we study the impact of terminal mobility on the performance of a panel-based LIS, considering different resource allocation approaches (including panel selection and/or panel-terminal association) and small panel areas. Such configuration represents a clear advantage in terms of flexibility, together with the fact that, from an economy of scale perspective, the production of this type of configuration choosing smaller areas seems more foreseeable.Our performance results show that there is no need to have a contagious distribution of panels, instead they can be physically separated according to a given distribution. It is also observed that, keeping a regularly fixed or predefined panel scheme, leading only to panel-terminal association, are able to fight against the unpredictability of terminal movements and overcome the computational complexity imposed by the optimum approach (that includes both panel selection and terminal-panel allocation stages), presenting maximum rate losses of 16-30%.
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| 49. |
- Piccoli, Francesco, et al.
(author)
-
FuSSI-Net: Fusion of Spatio-temporal Skeletons for Intention Prediction Network
- 2020
-
In: Conference Record - Asilomar Conference on Signals, Systems and Computers. - 1058-6393. ; 2020-November, s. 68-72
-
Conference paper (peer-reviewed)abstract
- Pedestrian intention recognition is very important to develop robust and safe autonomous driving (AD) and advanced driver assistance systems (ADAS) functionalities for urban driving. In this work, we develop an end-to-end pedestrian intention framework that performs well on day- and night- time scenarios. Our framework relies on objection detection bounding boxes combined with skeletal features of human pose. We study early, late, and combined (early and late) fusion mechanisms to exploit the skeletal features and reduce false positives as well to improve the intention prediction performance. The early fusion mechanism results in AP of 0.89 and precision/recall of 0.79/0.89 for pedestrian intention classification. Furthermore, we propose three new metrics to properly evaluate the pedestrian intention systems. Under these new evaluation metrics for the intention prediction, the proposed end-to-end network offers accurate pedestrian intention up to half a second ahead of the actual risky maneuver.
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| 50. |
- Rusek, Fredrik, et al.
(author)
-
An Information Theoretic Charachterization of Channel Shortening Receivers
- 2013
-
In: 2013 Asilomar Conference on Signals, Systems and Computers. - 1058-6393. ; , s. 2108-2112
-
Conference paper (peer-reviewed)abstract
- Optimal data detection of a linear channel can always be implemented through the Viterbi algorithm (VA). However, in many cases of interest the memory of the channel prohibits application of the VA. A popular and conceptually simple method in this case, studied since the early 70s, is to first filter the received signal in order to shorten the memory of the channel, and then to apply a VA that operates with the shorter memory. We shall refer to this as a channel shortening (CS) receiver. Although studied for almost four decades, an information theoretic understanding of what such simple receiver solution is actually doing is not available. In this paper we will show that an optimized CS receiver is implementing the chain rule of mutual information, but only up to the shortened memory that the receiver is operating with. Further, we will show that the tools for analyzing the ensuing achievable rates from an optimized CS receiver are precisely the same as the tools that are used for analyzing the achievable rates of an minimum mean square error (MMSE) receiver.
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