101 citations · 363 across the 33 of their papers we have counts for
21 papers · 1 filter
Channel Charting for Streaming CSI Data
Sueda Taner, Maxime Guillaud, Olav Tirkkonen +1
Channel charting (CC) applies dimensionality reduction to channel state information (CSI) data at the infrastructure basestation side with the goal of extracting pseudo-position in…
Wireless Channel Charting: Theory, Practice, and Applications
Paul Ferrand, Maxime Guillaud, Christoph Studer +1
Channel charting is a recently proposed framework that applies dimensionality reduction to channel state information (CSI) in wireless systems with the goal of associating a pseudo…
Optimal Bandwidth Allocation for Multicast-Cache-Aided on-Demand Streaming in Wireless Networks
Mohsen Amidzadeh, Giuseppe Caire, Olav Tirkkonen
We consider a hybrid delivery scheme for streaming content, combining cache-enabled Orthogonal Multipoint Multicast (OMPMC) and on-demand Single-Point Unicast (SPUC) transmissions…
Joint Channel Estimation and Data Detection in Cell-Free Massive MU-MIMO Systems
Haochuan Song, Tom Goldstein, Xiaohu You +3
We propose a joint channel estimation and data detection (JED) algorithm for densely-populated cell-free massive multiuser (MU) multiple-input multiple-output (MIMO) systems, which…
Fundamental Rate-Memory Tradeoff for Coded Caching in Presence of User Inactivity
Jialing Liao, Olav Tirkkonen
Coded caching utilizes proper file subpacketization and coded delivery to make full use of the multicast opportunities in content delivery, to alleviate file transfer load in massi…
Binary Subspace Chirps
Tefjol Pllaha, Olav Tirkkonen, Robert Calderbank
We describe in details the interplay between binary symplectic geometry and quantum computation, with the ultimate goal of constructing highly structured codebooks. The Binary Chir…
Reconfigurable Intelligent Surface Empowered Device-to-Device Communication Underlaying Cellular Networks
Gang Yang, Yating Liao, Ying-Chang Liang +1
Reconfigurable intelligent surface (RIS) is a new and revolutionary technology to achieve spectrum-, energy- and cost-efficient wireless networks. This paper studies the resource a…
Reconstruction of Multi-user Binary Subspace Chirps
Tefjol Pllaha, Olav Tirkkonen, Robert Calderbank
We consider codebooks of Complex Grassmannian Lines consisting of Binary Subspace Chirps (BSSCs) in dimensions. BSSCs are generalizations of Binary Chirps (BCs), their en…
Code Design Principles for Ultra-Reliable Random Access with Preassigned Patterns
Christopher Boyd, Roope Vehkalahti, Olav Tirkkonen +1
We study medium access control layer random access under the assumption that the receiver can perform successive interference cancellation, without feedback. During recent years, a…
Non-Orthogonal Contention-Based Access for URLLC Devices with Frequency Diversity
Christopher Boyd, Radosław Kotaba, Olav Tirkkonen +1
We study coded multichannel random access schemes for ultra-reliable low-latency uplink transmissions. We concentrate on non-orthogonal access in the frequency domain, where users…
Channel Charting: Locating Users within the Radio Environment using Channel State Information
Christoph Studer, Saïd Medjkouh, Emre Gönültaş +2
We propose channel charting (CC), a novel framework in which a multi-antenna network element learns a chart of the radio geometry in its surrounding area. The channel chart capture…
MmWave Channel Estimation via Atomic Norm Minimization for Multi-User Hybrid Precoding
Junquan Deng, Olav Tirkkonen, Christoph Studer
To perform multi-user multiple-input and multiple-output transmission in millimeter-wave(mmWave) cellular systems, the high-dimensional channels need to be estimated for designing…
Density of Spherically-Embedded Stiefel and Grassmann Codes
Renaud-Alexandre Pitaval, Lu Wei, Olav Tirkkonen +1
The density of a code is the fraction of the coding space covered by packing balls centered around the codewords. This paper investigates the density of codes in the complex Stiefe…
Volume of Metric Balls in High-Dimensional Complex Grassmann Manifolds
Renaud-Alexandre Pitaval, Lu Wei, Olav Tirkkonen +1
Volume of metric balls relates to rate-distortion theory and packing bounds on codes. In this paper, the volume of balls in complex Grassmann manifolds is evaluated for an arbitrar…
From Random Matrix Theory to Coding Theory: Volume of a Metric Ball in Unitary Group
Lu Wei, Renaud-Alexandre Pitaval, Jukka Corander +1
Volume estimates of metric balls in manifolds find diverse applications in information and coding theory. In this paper, some new results for the volume of a metric ball in unitary…
A Low-Complexity Message Recovery Method for Compute-and-Forward Relaying
Amaro Barreal, Joonas Pääkkönen, David Karpuk +2
The Compute-and-Forward relaying strategy achieves high computation rates by decoding linear combinations of transmitted messages at intermediate relays. However, if the involved r…
A Blind Time-Reversal Detector in the Presence of Channel Correlation
Zhong Zheng, Lu Wei, Jyri Hämäläinen +1
A blind target detector using the time reversal transmission is proposed in the presence of channel correlation. We calculate the exact moments of the test statistics involved. The…
Locally Best Invariant Test for Multiple Primary User Spectrum Sensing
Lu Wei, Prathapasinghe Dharmawansa, Olav Tirkkonen
We consider multi-antenna cooperative spectrum sensing in cognitive radio networks, when there may be multiple primary users. A noise-uncertainty-free detector that is optimal in t…
Approximation to Distribution of Product of Random Variables Using Orthogonal Polynomials for Lognormal Density
Zhong Zheng, Lu Wei, Jyri Hämäläinen +1
We derive a closed-form expression for the orthogonal polynomials associated with the general lognormal density. The result can be utilized to construct easily computable approxima…
On the Exact Distribution of the Scaled Largest Eigenvalue
Lu Wei, Olav Tirkkonen, Prathapasinghe Dharmawansa +1
In this paper we study the distribution of the scaled largest eigenvalue of complexWishart matrices, which has diverse applications both in statistics and wireless communications.…
Spectrum Sensing in the Presence of Multiple Primary Users
Lu Wei, Olav Tirkkonen
We consider multi-antenna cooperative spectrum sensing in cognitive radio networks, when there may be multiple primary users. A detector based on the spherical test is analyzed in…