43 citations · 45 across the 14 of their papers we have counts for
16 papers
Unified Evaluation Methodology for AI-Native Integrated Sensing and Communication
Filip Lemic, Andra Blaga, Francesco Devoti +24
Integrated Sensing and Communication (ISAC) couples radio sensing, data transmission, and control actions within a single closed-loop system. When Artificial Intelligence (AI)-driv…
CRB-Optimal Arrays and Waveforms in Active Sensing: Role of Redundancy and Spatial Covariance of Array Geometry
Ids van der Werf, Robin Rajamäki, Geert Leus
This paper characterizes the performance limits of optimal array designs using orthogonal and coherent waveforms for both linear and planar arrays. For orthogonal waveforms, we sho…
Grassmannian-Coded Beamforming for mmWave Channel Sensing with Unknown Complex Path Gain
Parthasarathi Khirwadkar, Robin Rajamäki, Piya Pal
This paper introduces a subspace-coding perspective to millimeter-wave channel sensing with a single RF chain when the complex channel gain is unknown. We show that in this case, c…
Beyond-Diagonal RIS: Adversarial Channels and Optimality of Low-Complexity Architectures
Atso Iivanainen, Robin Rajamäki, Visa Koivunen
Beyond-diagonal reconfigurable intelligent surfaces (BD-RISs) have recently gained attention as an enhancement to conventional RISs. BD-RISs allow optimizing not only the phase, bu…
Generative Deep Synthesis of MIMO Sensing Waveforms with Desired Transmit Beampattern
Vesa Saarinen, Robin Rajamäki, Visa Koivunen
This paper develops a generative deep learning model for the synthesis of multiple-input multiple-output (MIMO) active sensing waveforms with desired properties, including constant…
Subspace Coding for Spatial Sensing
Hessam Mahdavifar, Robin Rajamäki, Piya Pal
A subspace code is defined as a collection of subspaces of an ambient vector space, where each information-encoding codeword is a subspace. This paper studies a class of spatial se…
Sparse Spatial Smoothing: Reduced Complexity and Improved Beamforming Gain via Sparse Sub-Arrays
Yinyan Bu, Robin Rajamäki, Anand Dabak +3
This paper addresses the problem of single snapshot Direction-of-Arrival (DOA) estimation, which is of great importance in a wide-range of applications including automotive radar.…
Importance of array redundancy pattern in active sensing
Robin Rajamäki, Piya Pal
This paper further investigates the role of the array geometry and redundancy in active sensing. We are interested in the fundamental question of how many point scatterers can be i…
On array geometry and self-interference in full-duplex massive MIMO communications
Robin Rajamäki, Risto Wichman
This paper studies the role of the joint transmit-receive antenna array geometry in shaping the self-interference (SI) channel in full-duplex communications. We consider a simple s…
Harnessing Holes for Spatial Smoothing with Applications in Automotive Radar
Yinyan Bu, Robin Rajamäki, Pulak Sarangi +1
This paper studies spatial smoothing using sparse arrays in single-snapshot Direction of Arrival (DOA) estimation. We consider the application of automotive MIMO radar, which tradi…
Effect of Beampattern on Matrix Completion with Sparse Arrays
Robin Rajamäki, Mehmet Can Hücümenoğlu, Pulak Sarangi +1
We study the problem of noisy sparse array interpolation, where a large virtual array is synthetically generated by interpolating missing sensors using matrix completion techniques…
On the Impossibility of Lossless Waveform Rank Reduction for Certain Redundant Arrays
Robin Rajamäki, Piya Pal
Efficient use of spatio-temporal resources, including sensor arrays and transmit waveforms, is a key challenge in modern MIMO active sensing systems. This paper studies the impact…
Super-resolution with Sparse Arrays: A Non-Asymptotic Analysis of Spatio-temporal Trade-offs
Pulak Sarangi, Mehmet Can Hucumenoglu, Robin Rajamaki +1
Sparse arrays have emerged as a popular alternative to the conventional uniform linear array (ULA) due to the enhanced degrees of freedom (DOF) and superior resolution offered by t…
Hybrid Beamforming for Active Sensing using Sparse Arrays
Robin Rajamäki, Sundeep Prabhakar Chepuri, Visa Koivunen
This paper studies hybrid beamforming for active sensing applications, such as millimeter-wave or ultrasound imaging. Hybrid beamforming can substantially lower the cost and power…
Analog Beamforming for Active Imaging using Sparse Arrays
Robin Rajamäki, Sundeep Prabhakar Chepuri, Visa Koivunen
This paper studies analog beamforming in active sensing applications, such as millimeter-wave radar or ultrasound imaging. Analog beamforming architectures employ a single RF-IF ch…
Planar additive bases for rectangles
Jukka Kohonen, Visa Koivunen, Robin Rajamäki
We study a generalization of additive bases into a planar setting. A planar additive basis is a set of non-negative integer pairs whose vector sumset covers a given rectangle. Such…