1 Analysis of a Mixed Strategy for Multiple Relay Networks (2009)
Peter Rost, Student Member, Gerhard Fettweis, Senior Member
Abstract — Infrastructure based wireless communications systems as well as ad hoc networks experience a growing importance in present-day telecommunications. An increased density and popularity of...
Protocols and Performance Limits for Half-Duplex Relay Networks (2009)
Rost, Peter, Fettweis, Gerhard
This paper concentrates on relaying as one possibility to improve data rates in next-generation mobile networks. More specifically, it introduces protocols and analyzes performance limits in the...
Capacity Analysis for OFDM Systems with Transceiver I/Q Imbalance (2009)
Stefan Krone, Gerhard Fettweis
Abstract—OFDM systems have gained utmost importance for wireless communications requiring ever higher data rates. The maximum data rate that can be achieved is, however, limited by the wireless...
Blind Turbo Channel Estimation of QAM Signals exploiting Code Constraints (2009)
Wolfgang Rave, Gerhard Fettweis
Abstract—We present a blind turbo equalizer for QAM signals that exploits the statistics that a channel code imposes on the transmitted signal. The receiver is an adaptation of previous work...
Achievable Rates in Gaussian Half-Duplex Multiple Relay Networks (2009)
Peter Rost, Student Member, Gerhard Fettweis, Senior Member
Abstract — In this paper we analyze several protocols for Gaussian half-duplex multiple relay networks where each node either transmits or receives on a particular resource. We present achievable...
Optimal LLR Clipping Levels for Mixed Hard/Soft Output Detection (2009)
Ernesto Zimmermann, David L. Milliner, John R. Barry, Gerhard Fettweis
Abstract—Consider a communications system where the detector generates a mix of hard and soft outputs, which are then fed into a soft-input channel decoder. In such a setting, it is of interest to...
Transmitter-based Minimization of Error Rates in the Downlink of Wireless Systems (2009)
Fred Richter, Andreas Fischer, René Habendorf, Gerhard Fettweis
Abstract—Using CDMA technology, one has to contend with interference in frequency-selective channels caused by multipath propagation and fading. Transmitter-based methods such as Zero Forcing Joint...
A Real-Time Programming Model for Heterogeneous MPSoCs (2009)
Torsten Limberg, Bastian Ristau, Gerhard Fettweis
Abstract. Modern multi-core processors suffer from the lack of a programming model which allows efficient utilization of the available hardware. Massive software overhead is required to handle task...
Patrick Marsch, Gerhard Fettweis, Vodafone Chair, Mobile Comunications Systems
It is well-known that the main capacity limitation in cellular communication systems is due to inter-cell interference. Multi-cell signal processing, for example joint transmission from multiple base...
A Mapping Framework for Guided Design Space Exploration of Heterogeneous MP-SoCs (2009)
Bastian Ristau, Torsten Limberg, Gerhard Fettweis
When designing heterogeneous MP-SoCs designers have to take into account various objectives such as power, die size, flexibility, performance or programmability. But to be able to evaluate a given...
Andreas Frotzscher, Gerhard Fettweis
Abstract — In frequency division duplex transceivers the transmit signal is leaking through the duplexer into the receive branch. For the case of Zero-IF receivers the nonlinearity of the I/Q down...
Channel State Information Based LLR Clipping in List MIMO Detection (2009)
David L. Milliner, Ernesto Zimmermann, John R. Barry, Gerhard Fettweis
Abstract—Suboptimal detection schemes, such as list MIMO detection, often face the challenge of having to “guess ” at the decision reliability for some of the detected bits. A simple yet...
David L. Milliner, Ernesto Zimmermann, John R. Barry, Gerhard Fettweis
This work establishes bounds on the computational complexity of list MIMO detectors. Specifically, upper and lower bounds are introduced, where computational complexity is measured in terms of the...
Patrick Marsch, Gerhard Fettweis
(The original publication is available at www.springerlink.com) Abstract Recent work has shown that multi-cell cooperative signal processing in cellular networks can significantly increase system...
Iterative blind receiver exploiting channel code constraints for 60 GHz UWB channels (2009)
Wolfgang Rave, Gerhard Fettweis
it likely that a worldwide Ultra Wideband (UWB) standard at the frequency range of 60 GHz will emerge. A main challenge for UWB transmission at bandwidth B> 500 MHz is to estimate the possibly...
On the Capacity of OFDM Systems with Receiver I/Q Imbalance (2009)
Stefan Krone, Gerhard Fettweis
Abstract—OFDM systems have gained outstanding popularity for high data rate wireless communications. In practice, however, the performance of OFDM systems is often limited due to hardware...
Gerhard Fettweis, Ernesto Zimmermann
Information and communications technology (ICT) systems are the core of today’s knowledge based society. Innovations in this area are adapted at tremendous speed and worldwide use of ICT has soared...
Pre-Equalization for TDD Systems with Imperfect Transceiver Calibration (2009)
René Habendorf, Gerhard Fettweis
Abstract—We investigate nonlinear pre-equalization techniques for the downlink of multi-user systems from a transmitter equipped with multiple antennas to non-cooperative single antenna mobile...
A Fully Programmable 40 GOPS SDR Single Chip Baseband for LTE/WiMAX Terminals (2009)
Torsten Limberg, Markus Winter, Marcel Bimberg, Reimund Klemm, Gerhard Fettweis, ...
Abstract — The increasing number of radio protocols along with the need for multimedia support in mobile communication devices call for heterogeneous, programmable multi-core processors. In this...
Algorithm for Detecting the Number of Transmit Antennas in MIMO-OFDM Systems (2009)
Eckhard Ohlmer, Ting-jung Liang, Gerhard Fettweis
Abstract—In wireless MIMO-OFDM systems, knowledge of the channel between all transmit-receive antenna pairs is essential to enable the decoupling of spatial streams and coherent data detection at a...
Analysis of a General Mixed Strategy for Gaussian Multiple Relay Channels (2009)
Peter Rost, Student Member, Gerhard Fettweis, Senior Member, Mark Paper Cover, ...
proposed different coding strategies for the relay channel with a single relay supporting a communication pair. These strategies are the decode-and-forward and compress-and-forward approach. They...
Multiuser Transmission in Cellular Systems With Different Sector Configurations (2009)
Ines Riedel, René Habendorf, Ernesto Zimmermann, Gerhard Fettweis
Abstract—This paper considers the downlink for multiuser systems with a multiple antenna base station site and noncooperative single antenna mobile stations. Traditionally, the goal of the base...
On the Performance of OFDM downlink FDD channels under Tx Leakage using zero-IF receivers (2009)
Andreas Frotzscher, Marco Krondorf, Gerhard Fettweis
Abstract — Transmitter Leakage has a significant impact on frequency division duplex transceivers in mobile devices using zero-IF receivers. In this contribution, the statistical properties of the...
Thomas Schuster, Bruno Bougard, David Novo Bruna, Emil Matus, Gerhard Fettweis
The wide range of future and existing standards in wireless communications calls for flexible solutions. A way to introduce flexibility to digital radio systems is to replace hardwired components by...
Adaptive Radio Resource Management for a Cellular System with Fixed Relay Nodes (2009)
Fredrik Boye, Peter Rost, Student Member, Gerhard Fettweis, Senior Member
Abstract — Future mobile communications systems demand for higher data rates and service quality compared to state-of-the-art systems. One way to achieve this ambitious goal is to use relaying...
Protocols For Half-Duplex Multiple Relay Networks (2009)
Peter Rost, Student Member, Gerhard Fettweis, Senior Member
Abstract — In this paper we present several strategies for multiple relay networks which are constrained by a half-duplex operation, i. e., each node either transmits or receives on a particular...
Blind Turbo Multipath Channel Estimation of PAM Signals Exploiting Multilevel Codes (2009)
Wolfgang Rave, Gerhard Fettweis
Abstract — We present a blind turbo equalizer for Pulse Amplitude Modulation (PAM) signals that exploits the statistics that a multilevel code imposes on the transmitted signal. The receiver here...
System Performance Analysis of Single-Path and Cooperative MIMO Relaying (2009)
Peter Rost, Student Member, Fredrik Boye, Gerhard Fettweis, Senior Member
Abstract — The demand for even higher data rates in future mobile communications systems calls for new techniques capable of improving the performance of cellular systems. One possibility are relay...
Abstract Integrated Code Generation by Using Fuzzy Control System (2009)
Xiaoyan Jia, Jie Guo, Gerhard Fettweis
High quality code generation for DSPs that consist of irregular architectures is a challenge in terms of problem complexity. Since such problems are divided into several separated subtasks in the...
A Framework for Fixed Complexity Breadth-First MIMO Detection (Invited Paper) (2009)
David L. Milliner, Ernesto Zimmermann, John R. Barry, Gerhard Fettweis
Abstract—In this work we present a unifying framework to characterize different types of breadth-first tree search detectors for multiple antenna systems. All considered algorithms operate at fixed...
A Mapping Framework Based on Packing for Design Space Exploration of Heterogeneous MPSoCs ∗ (2009)
Bastian Ristau, Torsten Limberg, Gerhard Fettweis
The computational demand of signal processing algorithms is rising continuously. Heterogeneous embedded multiprocessor systems-on-chips are one solution to satisfy this demand. But to be able to take...
Linear Programming in Embedded Systems (2009)
Bastian Ristau, Gerhard Fettweis, Vodafone Chair, Tu Dresden
In the past signal processing algorithms for mobile communications systems were implemented in hardware using a single chip solution, usually a Digital Signal Processor (DSP). But due to the
Eckhard Ohlmer, Ting-jung Liang, Gerhard Fettweis
Abstract—Knowledge of the channel between all transmitreceive antenna pairs is essential for enabling the decoupling of spatial streams and coherent data detection in wireless MIMO-OFDM systems....
On the Efficiency of the Sequential Detector for Solving Soft-Output Detection Problems (2009)
Ernesto Zimmermann, Gerhard Fettweis
Abstract—Combining tree search detection with iterative detection-decoding allows achieving near-capacity performance in multiple antenna systems. In this contribution we show that the list...
SIC based Multi-user Turbo Detector for Non Gray Mapping in Distributed Antenna Systems (2009)
Shahid Khattak, Wolfgang Rave, Gerhard Fettweis, Vodafone Stiftungslehrstuhl, Mobile Nachrichtensysteme
Abstract — This paper deals with the multi-user detection for non Gray mappings in an uplink-OFDM system. Joint multiuser detection is made possible through the use of distributed antenna systems....
ON THE INTERACTION BETWEEN DSP-ALGORITH MS AND VLSI-ARCH ITECTURE ABSTRACT (2009)
Gerhard Fettweis, Heinrich Meyr
The evolving field of ASIC design enables the customized implementation of DSP-algorithms on dedicated chips. It therefore on the one hand opens up a number of new pos-sibilities, on the other hand...
JointDeploymentofMacro-andMicrocells in UTRANFDDNetworks (2008)
Patrick Herhold, Wolfgang Rave, Gerhard Fettweis
ABSTRACT — In recent years, the WCDMA radio network performance has been studied with the focus on deployment of sectorized macrocells. The macrocellular layer will be enhanced by microcell base...
Improved Methods for Search Radius Estimation in Sphere Detection Based MIMO Receivers (2008)
Patrick Marsch, Ernesto Zimmermann, Gerhard Fettweis
Abstract — Recently, communication systems with multiple transmission and reception antennas (MIMO) have been introduced and proven to be suitable for achieving a high spectral efficiency. Assuming...
Nonlinear Optimization for the Multiuser Downlink (2008)
René Habendorf, Gerhard Fettweis
Abstract — We investigate nonlinear pre-equalization techniques for the downlink of multiuser systems from a transmitter equipped with multiple antennas to noncooperative single antenna mobile...
NONLINEAR PREDISTORTION FOR OFDM SDMA SYSTEMS (2008)
René Habendorf, Gerhard Fettweis
This paper investigates nonlinear predistortion techniques for the downlink of OFDM systems from a transmitter equipped with multiple antennas to non-cooperative single antenna mobile stations....
Torsten Limberg, Emil Matus, Hendrik Seidel, Gerhard Fettweis
In this paper we descibe a novel platform for design space exploration and design implementation. A hardware model and a complete software tool chain including a compiler is generated from a XML...
ADAPTIVE VS. HYBRID ITERATIVE MIMO RECEIVERS BASED ON MMSE LINEAR AND SOFT-SIC DETECTION (2008)
Ernesto Zimmermann, Gerhard Fettweis
In this paper, we propose the use of a combination of linear MMSE and soft successive interference cancellation based detectors for the application in (Turbo-)MIMO receivers. In an adaptive setup we...
MATLAB BASED CODESIGN FRAMEWORK FOR WIRELESS BROADBAND COMMUNICATION DSPS (2008)
Matthias Weiss, Michael Bolle, Gerhard Fettweis
We provide an overview of a novel MATLABT “ based Hardware-Software design flow that has been applied to the design of a platform based SoC for the HiperLAN/2 and IEEE 802.1 1 a wideband wireless...
Using LISATek for the Design of an ASIP Core including Floating Point Operations (2008)
Reimund Klemm, Javier Prieto Sabugo, Hendrik Ahlendorf, Gerhard Fettweis
Application specific instruction set processors (ASIPs) recently became more important to overcome compute bottlenecks in digital signal processing systems with tight power constraints. Within the...
Abstract PERFORMANCE IMPROVEMENT IN DS-SPREAD SPECTRUM CDMA (2008)
André Noll Barreto, Gerhard Fettweis
The Rake receiver is a well known technique in spread spectrum systems, which is used to obtain signal diversity in multipath environments. In TDD systems, a technique known as pre-Rake has been...
HANDOVER PARAMETER OPTIMIZATION IN WCDMA USING FUZZY CONTROLLING (2008)
Christina Werner, Jens Voigt, Shahid Khattak, Gerhard Fettweis
The increasing traffic and the demand for high data rate services in WCDMA networks prompt the need for an automatic network optimization. Current state–of–the–art optimization methods adapt...
On Preamble Length of OFDM-WLAN (2008)
Ting-jung Liang, Wolfgang Rave, Gerhard Fettweis
Abstract — A preamble technique for synchronization and channel estimation introduces transmission delay and wastes capacity unavoidably due to the time loss before data transmission. In this...
OFDM-based Medium Access with Rate Constraints (2008)
Thomas Deckert, Gerhard Fettweis
Abstract — For wireless local area networks based on OFDM we study the sum rate of time and frequency division multiple access (TDMA, OFDMA) as well as superimposed transmission (SUP). In the...
List Sequential MIMO Detection: Noise Bias Term and Partial Path Augmentation (2008)
Steffen Bittner, Ernesto Zimmermann, Wolfgang Rave, Gerhard Fettweis
Abstract — Near-capacity performance can be achieved in multiple-antenna systems by using a list sequential (LISS) detector for iterative equalization. Path augmentation is known to increase the...
DOI: 10.1007/s10776-006-0046-x Dirty RF: A New Paradigm (2008)
Gerhard Fettweis, Michael Löhning, Denis Petrovic, Marcus Windisch, Peter Zillmann, Wolfgang Rave
Wireless communications systems have seen a rapid development in recent years, with an approximate ten-fold increase in data rates every 5 years. Current research and standardization efforts indicate
A Low-Complexity Scheduling for Turbo Equalization with Turbo Decoding (2008)
Wolfgang Rave, Gerhard Fettweis
Abstract — A novel scheduling for turbo equalization with turbo decoding is proposed. The use of turbo codes associated to turbo equalizers has been frequently investigated in the literature. The...
PERFORMANCE COMPARISON OF OFDM TRANSMISSION AFFECTED BY PHASE NOISE WITH (2008)
Abstract. Oscillator phase noise present in OFDM systems limits the performance by producing a common phase error and additional intercarrier interference. While phase noise is most often modelled as...
René Habendorf, Ralf Irmer, Wolfgang Rave, Gerhard Fettweis
Spread spectrum CDMA systems suffer from interference in frequency-selective channels. By applying Multiuser Transmission (MUT) methods in the base station in conjunction with smart antennas, the...
Space-Time Trellis Coding Exploiting Superimposed Transmissions in Half-Duplex Relay Networks (2008)
Peter Rost, Student Member, Gerhard Fettweis, Senior Member
Abstract — This work presents and analyzes a cooperative relaying approach which offers large scale spatial diversity and an additional coding advantage in a virtual antenna array. It utilizes a...
system concept development for 1 Gbit/s air interface Abstract — The WIGWAM 1 research project (Wireless Gigabit with Advanced Multimedia) is aimed at designing a 1 Gbit/s system concept for the...
PERFORMANCE ANALYSIS OF ITERATIVE MIMO-OFDM RECEIVERS UNDER THE PRESENCE OF PHASE NOISE (2008)
Steffen Bittner, Ernesto Zimmermann, Wolfgang Rave, Gerhard Fettweis
The performance of multicarrier transmission in combination with multiple antennas (e.g. MIMO-OFDM) can be drastically degraded due to the existence of RF impairments, e.g. phase noise (PN). In this...
Interconnection Architecture For System-on-Chip Design Providing Little Overhead (2008)
Markus Winter, Gerhard Fettweis
Increasing levels of on chip system integration means that more functional units need to be interconnected. In this paper an interconnection scheme is proposed ensuring communication between several...
Michael Löhning, Gerhard Fettweis
Designing leading-edge systems (e.g., communications systems) requires knowledge about the technological limits. Jitter is the limiting effect in wideband ADCs with a digitization bandwidth between 1...
Ines Riedel, Marcus Windisch, Gerhard Fettweis
Abstract — The low-IF receiver is very attractive, because the need for an analog image rejection filter is avoided. Instead, the image rejection is realized by I/Q signal processing. However,...
Nonlinear Predistortion with Reduced Peak-to-Average Power Ratio (2008)
René Habendorf, Wolfgang Rave, Gerhard Fettweis
Abstract — This paper presents the extension of vector precoding, a generalization of the nonlinear Tomlinson-Harashima precoding, with a PAPR (peak-to-average power ratio) reduction technique for...
VECTOR PRECODING WITH BOUNDED COMPLEXITY (2008)
René Habendorf, Gerhard Fettweis
We investigate nonlinear pre-equalization techniques for the downlink of multiuser systems from a transmitter equipped with multiple antennas to non-cooperative single antenna mobile receivers. In...
Linear Multiuser Transmission for CDMA with Reduced Computational Complexity (2008)
Ralf Irmer, Jayesh Gaur, Gerhard Fettweis
Abstract — CDMA system capacity is interference limited. Whereas for the uplink Multiuser Detection can be applied, for the downlink Multiuser Transmission (MUT) is required. Using channel...
Marcus Windisch, Gerhard Fettweis
I/Q imbalance has been identified as one of the key challenges in the practical implementation of the direct-conversion receiver architecture. This holds in particular at the reception of...
Turbo Equalization for Clipped and Filtered COFDM Signals (2008)
Peter Zillmann, Wolfgang Rave, Gerhard Fettweis
Abstract — Clipping and filtering is an attractive method for the reduction of the PAPR of OFDM signals before transmission. However, the resulting in-band distortion noise impacts the error rate...
Tim Hentschel, Gerhard Fettweis
The main goal of the project is to break up the border between analog and digital signal processing in front-ends of mobile communication terminals as well as base-stations. The objective is to...
Coded Orthogonal Frequency Division Modulation (2008)
Branimir Stantchev, Joerg Kuehne, Marcus Bronzel, Gerhard Fettweis
Abstract: Future broadband picocellular networks demand powerful modulation and coding methods under the tight constraints of affordable modem complexity and low power consumption for the mobile...
ORTHOGONAL Frequency Division Multiplexing (2008)
Marco Krondorf, Fabian Diehm, Gerhard Fettweis
Abstract — In this paper we present an analytical approach to evaluate the M-QAM symbol error rate (SER) of Alamouti space time coded OFDM direct conversion receivers subject to carrier frequency...
SPIDER-NET: A Sensor Platform for Intelligent Ad-hoc Wireless Relaying Network (2008)
Katja Schwieger, Frank Schäfer, Konrad Seidel, Gerhard Fettweis
Abstract-As the name suggests SPIDERNET (Sensor Platform for Intelligent aD-hoc wireless Relaying NETwork) is a platform for a wireless sensor network developed at TU Dresden. Sensor networks can...
Limits of Phase Noise Suppression in OFDM (2008)
Denis Petrovic, Wolfgang Rave, Gerhard Fettweis
Abstract: We introduce two independent approaches for phase noise suppression. The dominant effects, responsible for the degradation of an OFDM system performance, if phase noise is present, are...
Adaptive I/Q Imbalance Compensation in Low-IF Transmitter Architectures (2008)
Marcus Windisch, Gerhard Fettweis
Abstract — Advanced transmitter architectures based on I/Q signal processing are highly attractive to applications demanding a reconfigurable setting of the transmission parameters, such as carrier...
GEC Plessy Semiconductors (2008)
Gerhard Fettweis, Razmik Karabed
Abstmct- The objective of this paper is to provide a gen-eral framework for optimizing the design of Viterbi detec-tors to achieve substantial reductions in hardware complex-ity as we11 as power...
On Ordering Optimization for MIMO Systems with Decentralized Receivers (2008)
René Habendorf, Gerhard Fettweis
Abstract — This paper addresses Tomlinson-Harashima Precoding (THP) for the downlink of multiuser systems, where the transmitter is equipped with multiple antennas and each decentralized receiver...
A Low Power Soft Core for Multi-Standard Video Applications (2008)
Hendrik Seidel, Pablo Robelly, Patrick Herhold, Gerhard Fettweis, Vodafone Chair
Abstract — Product life time and design reusability have become critical objectives for todays system on chip designs. To achieve long life cycles for high performance devices calls for increased...
MATLAB BASED CODESIGN FRAMEWORK FOR WIRELESS BROADBAND COMMUNICATION DSPS (2008)
Matthias Weiss, Michael Bolle, Gerhard Fettweis
We provide an overview of a novel MATLABT “ based Hardware-Software design flow that has been applied to the design of a platform based SoC for the HiperLAN/2 and IEEE 802.1 1 a wideband wireless...
The Digital Front-End – Bridge Between RFand Baseband-Processing (2008)
Tim Hentschel, Gerhard Fettweis
1.1 The front-end of a digital transceiver The first question that might arise is: What is the digital front-end? The notion of
Algorithms and Applications of Channel Impulse Response Length Estimation for MIMO-OFDM (2008)
Marco Krondorf, Ting-jung Liang, Martin Goblirsch, Gerhard Fettweis
Abstract — The performance of the widely applied timedomain channel estimation for SISO- and MIMO-OFDM systems strongly depends on the preciseness of information regarding maximum channel impulse...
SYSTEMS THROUGH JOINT SIGNAL PRECODING (2008)
André Noll Barreto, Gerhard Fettweis
Abstract- In this paper we propose two precoding schemes for the downlink of CDMA systems which help reduce the multiuser interference by jointly precoding the transmitted signal based on knowledge...
BLIND I/Q IMBALANCE PARAMETER ESTIMATION AND COMPENSATION IN LOW-IF RECEIVERS (2008)
Marcus Windisch, Gerhard Fettweis
The rejection of the image signal is a problem inherent to all receiver architectures. One of the benefits of the low-IF receiver is, that image rejection is realized by I/Q signal processing instead...
Denis Petrovic, Wolfgang Rave, Gerhard Fettweis, Senior Member
Abstract—In this paper, we propose an algorithm for suppressing intercarrier interference due to phase noise in coded orthogonal frequency division multiplexing (OFDM) systems. The algorithm...
On the Spectral Bitrate Loss of Superimposed Pilot and Preamble Synchronization (2008)
Ting-jung Liang, Ralf Irmer, Gerhard Fettweis
Abstract — In present packet-based wireless OFDM systems, such as IEEE802.11a/g, a preamble technique is used to accomplish the synchronization functions. Although this technique is well-developed,...
A distributed space-time trellis coding approach for multi-terminal relay networks (2008)
Peter Rost, Student Member, Gerhard Fettweis, Senior Member
Abstract — Cooperative relaying is a promising alternative for conventional mobile communications systems as it is able to increase coverage and throughput of these systems. Due to practical...
Iterative Joint Channel Estimation and Decoding Using Superimposed Pilots in OFDM-WLAN (2008)
Ting-jung Liang, Wolfgang Rave, Gerhard Fettweis
Abstract — A preamble technique is used in present OFDMbased WLAN systems to accomplish synchronization and channel estimation. The preamble introduces transmission delay and wastes capacity,...
Gerhard Fettweis, Ernesto Zimmermann, Tu Dresden
Abstract: As RF and baseband engineers strive to satisfy the demand for ever higher data rates in next generation wireless systems, they are faced with three challenging requirements: both spectral...
Channel-Matched Receiver for Throughput Enhancement in OFDM (2008)
Marco Krondorf, Gerhard Fettweis
Abstract: In this paper we present two throughput enhancing detection schemes for OFDM, all using the Frequency Domain Channel Length Indicator (FCLI) algorithm for improved channel estimation and...
BIT-FLIPPING POST-PROCESSING FOR FORCED CONVERGENCE DECODING OF LDPC CODES (2008)
Ernesto Zimmermann, Prakash Pattisapu, Gerhard Fettweis
The recently proposed forced convergence technique allows for reducing the decoding complexity of Low-Density Parity-Check Codes (LDPCC) at only slight deterioration in performance. The basic idea is...
Dirty RF: A New Paradigm InvitedP aper (2008)
Gerhard Fettweis, Michael Löhning, Denis Petrovic, Marcus Windisch, Peter Zillmann, Wolfgang Rave
Abstract — The implementation challenge for new low-cost low-power wireless modem transceivers has continuously been growing with increased modem performance, bandwidth, and carrier frequency. Up...
Achievable Rates Of Half-Duplex Relay Networks (2008)
Peter Rost, Student Member, Gerhard Fettweis, Senior Member
Abstract — This paper discusses two coding approaches for a network of half-duplex relay terminals and presents achievable rates for the discrete memoryless relay channel. Both proposals gain on an...
Iterative Phase Noise Mitigation in MIMO-OFDM Systems with Pilot Aided Channel Estimation (2008)
Steffen Bittner, Ernesto Zimmermann, Gerhard Fettweis
Abstract — The use of multiple transmit and receive antennas in combination with multicarrier modulation, e.g. MIMO-OFDM, is a very promising technique for future wireless communication systems. In...
On the Impact of User Positions on Multiuser (2008)
Shahid Khattak, Wolfgang Rave, Gerhard Fettweis
Abstract — This paper investigates the effect of user position on the performance of a near optimal SIC receiver in an uplink-OFDM system. Multi-user detection is made possible through cooperation...
Jürgen Deissner, Gerhard Fettweis, Jörg Fischer, Dietrich Hunold, Jens Voigt, Ralf Lehnert, ...
The rapidly increasing traffic demand from mobile users forces network operators and service providers to extend and optimize existing networks as well as to plan entirely new mobile radio networks....
Unbiased MMSE Tree Search Detection for Multiple Antenna Systems (2008)
Ernesto Zimmermann, Gerhard Fettweis
Abstract — Tree search based detection techniques allow to achieve near-capacity performance in iterative receivers for multiple antenna (MIMO) systems. In order to solve the detection problem not...
Distributed Iterative Multiuser Detection through Base Station Cooperation (2008)
Shahid Khattak, Wolfgang Rave, Gerhard Fettweis
This paper deals with multiuser detection through base station cooperation in an uplink, interference-limited, high frequency reuse scenario. Distributed iterative detection (DID) is an interference...
A parallel smart candidate adding algorithm for soft-output MIMO detection (2008)
Ernesto Zimmermann, Gerhard Fettweis, David L. Milliner, John R. Barry
Tree search schemes are an efficient means for solving the detection problem in multiple-input multiple-output systems. One option for implementing such a tree search is the smart candidate adding...
Blind Turbo Channel Estimation Exploiting Parity Check Equations (2008)
Wolfgang Rave, Gerhard Fettweis
This paper presents an iterative blind channel estimation algorithm that exploits the parity check equations of a channel code. While with conventional pilots prior data knowledge is used to estimate...
Baseband Analysis of Tx Leakage in WCDMA Zero-IF Receivers (2008)
Andreas Frotzscher, Gerhard Fettweis
Abstract — Frequency division duplex transceivers employing the Zero-IF principle suffers from Tx Leakage. In this contribution a baseband representation of the Tx Leakage impact in Zero-IF...
Statistics of a Blind Channel Estimator based on ’Logic Strings (2008)
Wolfgang Rave, Gerhard Fettweis
We derive the mean squared error (variance) of a blind channel estimator that exploits constraints imposed on valid combinations of code bits (also called ’logic strings’) and the respective...
OFDM Link Performance Analysis under Various Receiver Impairments (2008)
Marco Krondorf, Gerhard Fettweis
We present a methodology for OFDM link capacity and bit error rate calculation that jointly captures the aggregate effects of various real life receiver imperfections such as: carrier frequency...
Distributed Iterative Multiuser Detection through Base Station Cooperation (2008)
Shahid Khattak, Wolfgang Rave, Gerhard Fettweis
This paper deals with multiuser detection through base station cooperation in an uplink, interference-limited, high frequency reuse scenario. Distributed iterative detection (DID) is an interference...
A Development Platform for the Design and Optimization of Mobile Radio Networks (2007)
Jürgen Deissner, Gerhard Fettweis, Jörg Fischer, Dietrich Hunold, Jens Voigt, Ralf Lehnert, ...
The rapidly increasing traffic demand from mobile users forces network operators and service providers to extend and optimize existing networks as well as to plan entirely new mobile radio networks....
Breaking New Grounds Over 3000 MMAC/s: A Broadband Mobile Multimedia Modem DSP (2007)
Gerhard Fettweis, M. Weiss, W. Drescher, U. Walther, F. Engel, S. Kobayashi, ...
Future DSP architectures need to be developed for paving the way into a generation of high scale signal processing power, i.e. greater than 1000M MAC/s (multiply accumulate per second). This can only...
Using multiple antennas in the transmitter and/or in the receiver and exploiting all available knowledge about the channel in both the receiver and transmitter, the link capacity can be increased or...
0-7803-7442-8/02/$17.00 © 2002 IEEE MIMO Channel Estimation with Dimension Reduction (2007)
Matthias Stege, Peter Zillmann, Gerhard Fettweis
The number of channel estimates that have to be estimated in Multiple-Input Multiple-Output (MIMO) system is in general much larger, than in a single antenna communication scheme. This leads to lower...
New Recursive Algorithms for the Unified Forward and Inverse MDCT/MDST (2007)
Vladimir Nikolajevic, Gerhard Fettweis
Abstract. Forward and inverse MDCT are two of the most computationally intensive operations in the MPEG audio coding standard. In this paper we derive sinusoidal recursive formulas for transforming...
Reduced Complexity Space-Time Optimum Processing (2007)
Jens Jelitto, Marcus Bronzel, Gerhard Fettweis
New emerging space-time processing technologies promise a significant performance increase of wireless communication systems. The particular application and scenario strongly influences the amount of...
Joint Deployment of Macro- and Microcells in UTRAN FDD Networks (2007)
Patrick Herhold, Wolfgang Rave, Gerhard Fettweis
ABSTRACT — In recent years, the WCDMA radio network performance has been studied with the focus on deployment of sectorized macrocells. The macrocellular layer will be enhanced by microcell base...
Design methodology for digital signal processing (2007)
Improvements in semiconductor integration density and the resulting problem of having to manage designs of increasing complexity is an old one, but still current. The new challenge lies in a new...
A Space-Time Channel Model with Stochastic Fading Simulation (2007)
Matthias Stege, Jens Jelitto, Marcus Bronzel, Gerhard Fettweis
Abstract — The simulation of wireless communication systems with adaptive antennas requires a spatial channel model which reasonably characterizes the time-variant effects of the mobile radio...
1 Abstract On the Performance of Space-Time-Blockcodes (2007)
Matthias Stege, Marcus Bronzel, Gerhard Fettweis
Space-Time-Blockcodes (STBC), that have been introduced by Alamouti [1] and Tarokh et.al. [2], are now considered in the current 3GPP standard as one method to achieve spatial diversity. While the...
Wolfgang Rave, Thomas Köhler, Gerhard Fettweis, Jörg Huschke
ABSTRACT — The possibility of having two radio networks sharing a common set of frequencies is investigated for regular hexagonal cell layouts. While for a single network a hexagonal symmetry of...
II. SIGNAL MODEL Im folgenden soll ein flacher Schwundkanal mit nur einer (2007)
Matthias Stege, Tom Ruprich, Marcus Bronzel, Gerhard Fettweis, I. Einleitung
basierenden Übertragungssystems interferenzlimitiert. Damit ist auch die Anzahl der Nutzer pro Zelle, aber auch die maximale Datenrate begrenzt. Der Einsatz von mehreren Antennen ermöglicht eine...
142 SOFTWARE AND DSP IN RADIO Sample Rate Conversion for Software Radio (2007)
Tim Hentschel, Gerhard Fettweis
Software radio terminals must be able to process many various communications standards. These standards are generally based on different master clock rates and thus employ different bit/chip rates....
Sample Rate Conversion in Software Radio Terminals (2007)
Tim Hentschel, Matthias Henker, Gerhard Fettweis
Feasibility of Software Radio mainly depends on the availability of a suitable hardware platform. A basic feature of this hardware platform is the ability to process signals of different mobile...
A Design Methodology for High Performance ICs: Wireless Broadband Radio Baseband Case Study (2007)
Volker Aue, Johannes Kneip, Matthias Weiss, Michael Bolle, Gerhard Fettweis, Systemonic Ag
In this paper, we provide an overview of the Hardware-Software design flow that has been applied to the design of a platform based SoC for the HiperLAN/2 and IEEE 802.11a wideband wireless...
Jürgen Deissner, Gerhard Fettweis
Abstract- In today’s cellular networks it becomes harder to provide the resources exactly in the place and at the time where and when they are needed. Frequency planning for a hierarchical cellular...
Synchronizability of general periodic pattern signals (2007)
Branimir Stantchev, Gerhard Fettweis
Abstract — In this paper 1 an optimum and sub-optimum maximum likelihood (ML) rule for joint frame and carrier frequency offset estimation are derived, which rely on the transmission of a periodic...
Abstract Extended Algorithms for Sample Rate Conversion (2007)
Matthias Henker, Gerhard Fettweis
The idea of software radio (SWR) implies the capability of changing the air-interface just by down-loading the respective software. Since analog components (e.g., for prefiltering and digitization)...
Linear Precoding Approaches for the TDD DS-CDMA Downlink (2007)
Michael Joham, Ralf Irmer, Stefan Berger, Gerhard Fettweis, Wolfgang Utschick
We compare different approaches for linear precoding, i. e. processing applied prior to transmission. Our contribution is not only the comparison of the different transmit filters in the same...
Matthias Stege, Gerhard Fettweis
In rich scattering environments, wireless systems with multiple transmit and receive antennas (MIMO) offer large capacity gains. They are in general based on a parallel transmission of 1 ≤ M ≤ NT...
Relaying and Cooperation – A System Perspective (2007)
Patrick Herhold, Ernesto Zimmermann, Gerhard Fettweis
Abstract — The paper considers various relaying strategies for wireless networks. We comparatively discuss and analyse direct transmission, conventional “multihop ” relaying, and the novel...
Multi-Hop Transmission: Benefits and Deficits 1 Why (not) multi-hop? (2007)
Katja Schwieger, Gerhard Fettweis, Vodafone Stiftungslehrstuhl, Mobile Nachrichtensysteme
Sensor networks are supposed to operate with very little energy, are build of tens to thousands nodes and may be spread over large distances. In order to interconnect nodes in large areas while...
OFDM Link Performance Analysis under Various Receiver Impairments (2007)
Marco Krondorf, Gerhard Fettweis
We present a methodology for OFDM link capacity and bit error rate calculation that jointly captures the aggregate effects of various real life receiver imperfections such as: carrier frequency...
Marco Krondorf, Ting-jung Liang, Gerhard Fettweis
Abstract — In this paper we present an analytical approach to evaluate the symbol error rate (SER) of OFDM systems subject to carrier frequency offset (CFO) and channel estimation error in Rayleigh...
Soft Detection and Decoding of Clipped and Filtered COFDM Signals (2007)
Peter Zillmann, Wolfgang Rave, Gerhard Fettweis
Abstract — Clipping and filtering is an attractive method for the reduction of the PAPR of OFDM signals before transmission. However, the resulting distortion noise impacts the error rate...
On the Impact of I/Q Imbalance in Multi-Carrier Systems for Different Channel Scenarios (2007)
Marcus Windisch, Gerhard Fettweis
Abstract — I/Q imbalance has been identified as one of the most serious concerns in the practical implementation of the direct conversion receiver architecture. Facing the performance-degrading...
OFDM Link Performance Analysis under Various Receiver Impairments. Accepted for publication (2007)
Marco Krondorf, Gerhard Fettweis
Abstract — In this article, we present a methodology for OFDM link capacity and bit error rate calculation that jointly captures the aggregate effects of various real life receiver imperfections...
Marco Krondorf, Gerhard Fettweis
Abstract — In this paper we present an analytical approach to evaluate the bit error rate (BER) of OFDM systems subject to carrier frequency offset (CFO) and channel estimation error in Rayleigh...
A Generalized Mixed Strategy for Multiterminal Relay Networks (2007)
Peter Rost, Student Member, Gerhard Fettweis, Senior Member
Abstract — In their fundamental paper, Cover and El Gamal presented three basic coding strategies – decode-and-forward, compress-and-forward and a mixed strategy based on partial...
Generalized Smart Candidate Adding for Tree Search Based (2007)
Ernesto Zimmermann, Gerhard Fettweis
Abstract — Tree search schemes are an efficient means of solving the detection problem in MIMO systems. There exist two fundamentally different approaches when using such techniques for soft output...
Mapping and performance evaluation for heterogeneous MP-SoCs via packing (2007)
Bastian Ristau, Gerhard Fettweis
Abstract. The computational demand of signal processing algorithms is rising continuously. Heterogeneous embedded multiprocessor systems-on-chips are one solution to tackle this demand. But to be...
Reduced Complexity Vector Precoding for the Multiuser Downlink (2006)
René Habendorf, Ines Riedel, Gerhard Fettweis
Abstract — We investigate nonlinear precoding techniques for stations (MS), each equipped with a single receive antenna. the downlink of multi-user systems from a transmitter equipped with multiple...
Abstract — Future infrastructure based wireless systems are likely to use relaying due to energy savings, simpler roll-out of cellular networks, simpler increase of coverage and so forth. To...
Rate regions of asymmetrical multiple access with receive diversity (2006)
Thomas Deckert, Sebastian Kaiser, Gerhard Fettweis
Abstract — Based on the specification of a high-throughput wireless local area network system we consider the achievable rate regions of time, frequency and code division multiple accessing...
Linear MIMO Receivers vs. Tree Search Detection: A Performance Comparison Overview (2006)
Clemens Michalke, Ernesto Zimmermann, Gerhard Fettweis
Next generation wireless systems will use a combination of large system bandwidths and multiple antennas (MIMO) to deliver very high data rate services. The efficient demodulation of MIMO signals at...
Interconnection generation for system-on-chip design (2006)
Markus Winter, Gerhard Fettweis
Abstract – In recent years interconnection architectures for system-on-chip (SoC) design have been subject of intense research. The architectures range from clustered bus based systems to...
Complexity Reduction in Iterative MIMO Receivers Based on EXIT Chart Analysis (2006)
Ernesto Zimmermann, Steffen Bittner, Gerhard Fettweis
The application of the Turbo principle in MIMO receivers allows to achieve near-capacity performance with a number of different MIMO detection algorithms. However, this high performance is paid for...
Marcus Windisch, Gerhard Fettweis
Abstract — I/Q imbalance has been identified as one of the most serious concerns in the practical implementation of the direct conversion receiver architecture. In particular, at the reception of...
BER Performance Evaluation of a Continuous Transmission Cooperative Relaying Protocol (2006)
Peter Rost, Student Member, Gerhard Fettweis, Senior Member
Abstract — In this paper we derive an analytical solution for the end-to-end bit error rate of a novel interference cancellation based cooperative relaying protocol. It shows that our protocol...
Bastian Ristau, Gerhard Fettweis
Abstract. Applications for system on chips become more and more complex. Also the number of available components (DSPs, ASICs, Memories, etc.) rises continuously. These facts necessitate a structured...
Low Complexity Soft Interference Cancellation for MIMO Systems (2006)
Steffen Bittner, Ernesto Zimmermann, Gerhard Fettweis
Abstract — Iterative equalization has emerged as an efficient means of achieving near-capacity detection performance in multiple-antenna (MIMO) systems. However, many proposed detection strategies...
Marco Krondorf, Ting-jung Liang, Ralf Irmer, Gerhard Fettweis
Abstract: Using a priori knowledge of maximum channel impulse response (CIR) length, time domain OFDM channel estimation systems outperforms frequency domain channel estimation. Because CIR length is...
Improved length term calculation and MMSE extension for (2006)
Ernesto Zimmermann, Gerhard Fettweis
Abstract — List sequential (LISS) detection is an effective means of achieving near-capacity performance in iterative detection-decoding for MIMO systems. Using a length bias term calculated via an...
Optimized Receiver for Guard Interval free OFDM (2006)
Marco Krondorf, Gerhard Fettweis
Abstract — In this paper a novel detection scheme for guard interval free OFDM is presented, that uses the Frequency Domain Channel Length Indicator (FCLI) algorithm for improved channel estimation...
Error Probability Analysis of MultiCarrier Systems Impaired by Receiver I/Q Imbalance (2006)
Marcus Windisch, Gerhard Fettweis
Abstract — I/Q imbalance has been identified as one of the most serious concerns in the practical implementation of the direct conversion receiver architecture. In particular, at the reception of...
Power and Energy Consumption for Multi-Hop Protocols: A Sensor Network (2005)
Katja Schwieger, Gerhard Fettweis
Abstract — Information theoretic approaches often investigate power consumption of mobile nodes in wireless multi-hop networks. In high data rate systems high spectral efficiencies are required to...
Nonlinear Multiuser Precoding for Non-Connected Decision Regions (2005)
Rene Habendorf, Ralf Irmer, Wolfgang Rave, Gerhard Fettweis
Spread spectrum CDMA systems suffer from interference in frequency-selective channels. By applying Multiuser Transmission (MUT) methods in the base station in conjunction with smart antennas, the...
Paving the Way for Gigabit Networking (2005)
Jean-pierre Ebert, Eckhard Grass, Ralf Irmer, Rolf Kraemer, Gerhard Fettweis, Karl Strom, ...
Wired LANs soared to the gigabit level some years ago, and terabit networks are in place for wide area networking. However, in terms of data rate, wireless short-range networks tend to lag one...
MIMO Preamble Design With a Subset of Subcarriers in OFDM-based WLAN (2005)
Ting-jung Liang, Gerhard Fettweis
Abstract — This paper deals with how to design a MIMO preamble for OFDM-based WLAN with a subset of subcarriers, which decreases the performance of channel estimation in MIMO. A practical MIMO...
Development and Implementation of a 3.6 GFLOP/s SIMD-DSP using the Synopsys Toolchain (2005)
Hendrik Seidel, G. Cichon, E. Matúš, T. Limberg, P. Robelly, Gerhard Fettweis
Mobile communication systems, wireless and handheld terminals require low power, yet high performance DSPs. These DSPs are used in software defined radio applications and for computation of streaming...
On the performance of cooperative relaying protocols in wireless networks (2005)
Ernesto Zimmermann, Patrick Herhold, Gerhard Fettweis
Abstract — Cooperative relaying recently emerged as a viable option for future wireless networks. By simultaneously exploiting path loss savings known from relaying scenarios and the diversity...
Marcus Windisch, Gerhard Fettweis
The growing number of different mobile communications standards calls for inexpensive and highly flexible receiver architectures supporting these standards. The directconversion receiver is a very...
Marcus Windisch, Gerhard Fettweis
Abstract — The growing number of different mobile communications standards calls for inexpensive and highly flexible receiver architectures supporting these standards. The direct-conversion...
Synchronization in OFDM-Based WLAN with Transmit and Receive Diversities (2005)
Ting-jung Liang, Xin Li, Ralf Irmer, Gerhard Fettweis
Abstract — This paper 1 deals with the feasibility of improving synchronization (packet detection and frequency synchronization) of OFDM systems by exploiting transmit and receive diversities....
Ernesto Zimmermann, Wolfgang Rave, Gerhard Fettweis
Abstract: Recently, the concept of forced convergence decoding for Low-Density Parity-Check Codes has been introduced. Restricting the message passing in the iterative process to the nodes that still...
Properties of Intercarrier Interference due to Phase Noise (2005)
Denis Petrovic, Wolfgang Rave, Gerhard Fettweis
Abstract — We present a unified analysis of intercarrier interference (ICI) which is caused by phase noise in OFDM. The ”small ” phase noise approximation known from the literature is dropped...
Abstract Cooperative multi-hop transmission in wireless networks (2005)
Patrick Herhold, Ernesto Zimmermann, Gerhard Fettweis
We consider various relaying strategies for wireless networks by comparatively examining direct transmission, conventional relaying, and the novel concepts of cooperative relaying. The latter build...
On the impact of the physical layer on energy consumption in sensor networks (2005)
Katja Schwieger, Amrit Kumar, Gerhard Fettweis
Abstract — Collaborating networks built of hundreds or thousands of tiny, simple nodes, usually operating at low duty cycles, transmitting only few bytes of data are commonly referred to as sensor...
Iterative correction and decoding of OFDM signals affected by Clipping (2005)
Wolfgang Rave, Peter Zillmann, Gerhard Fettweis
Abstract We investigate iterative receive algorithms for orthogonal frequency division multiplexing (OFDM) transmission affected by clipping at the transmit power amplifier (PA). One algorithm aims...
A novel protocol for cooperative diversity in wireless networks (2004)
Ernesto Zimmermann, Patrick Herhold, Gerhard Fettweis
Abstract: Recently, cooperative diversity has emerged as a means of providing gains from spatial diversity to devices with single antennas. Yet, the performance of these protocols remains limited in...
R.Leupers, “Compiler based exploration of dsp energy savings by simd operations (2004)
Markus Lorenz, Peter Marwedel, Thorsten Dräger, Gerhard Fettweis
Abstract — The growing use of digital signal processors (DSPs) in embedded systems necessitates the use of optimizing compilers supporting their special architecture features. Beside the irregular...
The Impact of Cooperation on Diversity-Exploiting Protocols (2004)
Ernesto Zimmermann, Patrick Herhold, Gerhard Fettweis
Abstract — Cooperative relaying is a recently developed concept that allows for providing single-antenna devices with gains from spatial diversity. So far, the performance of those schemes has...
On the Performance of Cooperative Amplify-and-Forward Relay Networks (2004)
Patrick Herhold, Ernesto Zimmermann, Gerhard Fettweis
This paper provides a general analysis of cooperative amplify-and-forward relay networks and gives a unified and comparative view of various proposed systems. The studied cooperative relay networks...
Synchronous Transfer Architecture (STA) (2004)
Gordon Cichon, P. Robelly, H. Seidel, E. Matus, M. Bronzel, Gerhard Fettweis
This paper presents a novel micro-architecture for high-performance and low-power DSPs. The underlying Synchronous Transfer Architecture (STA) fills the gap between SIMD-DSPs and coarse-grain...
Gerhard Fettweis, Michael Löhning, Denis Petrovic, Marcus Windisch, Peter Zillmann, Ernesto Zimmermann
Future wireless communications systems are expected to provide ever higher data rates. Still, devices have to be produced at reasonable cost in order to be affordable to customers. The widely known...
Compiler Scheduling for STA-Processors (2004)
Gordon Cichon, P. Robelly, H. Seidel, M. Bronzel, Gerhard Fettweis
This paper presents an adaptation of the list scheduling algorithm to generate code for processors of the Synchronous Transfer Architecture (STA) by applying techniques known from RISC and TTA. The...
On the complexity of sphere decoding (2004)
Ernesto Zimmermann, Wolfgang Rave, Gerhard Fettweis
Abstract — Recently, sphere detection has emerged as a powerful means of finding the maximum likelihood solution to the detection problem for multiple-antenna (MIMO) systems. In this paper, we...
Common Phase Error due to Phase Noise in OFDM - Estimation and Suppression (2004)
Denis Petrovic, Wolfgang Rave, Gerhard Fettweis
Abstract- Orthogonal frequency division multiplexing (OFDM) has already become a very attractive modulation scheme for many applications. Unfortunately OFDM is very sensitive to synchronization...
SAMIRA: A SIMD-DSP architecture targeted to the Matlab source language (2004)
Gordon Cichon, Pablo Robelly, Hendrik Seidel, Torsten Limberg, Gerhard Fettweis, Vodafone Chair
This paper presents a novel processor architecture tailored to the efficient execution of digital signal processing algorithms efficiently that are developed using the Matlab TM programming language....
A Simple Cooperative Extension to Wireless Relaying (2004)
Patrick Herhold, Ernesto Zimmermann, Gerhard Fettweis
Abstract — We propose and analyze a simple protocol that simultaneously exploits two potentials offered by wireless relay systems: diversity gains and pathloss savings. An intermediate...
Standard-independent I/Q imbalance compensation in OFDM direct-conversion receivers (2004)
Marcus Windisch, Gerhard Fettweis
Abstract — The growing number of different mobile communications standards calls for inexpensive and highly flexible receiver architectures supporting all standards. The direct conversion receiver...
Reduced Complexity LDPC Decoding using Forced Convergence (2004)
Ernesto Zimmermann, Gerhard Fettweis
Abstract — Low-density parity-check (LDPC) codes have recently emerged as a viable option for forward error correction (FEC) in future wireless communications systems. One factor influencing the...
R.Leupers, “Compiler based exploration of dsp energy savings by simd operations (2004)
Markus Lorenz, Peter Marwedel, Thorsten Dräger, Gerhard Fettweis
Abstract — The growing use of digital signal processors (DSPs) in embedded systems necessitates the use of optimizing compilers supporting their special architecture features. Beside the irregular...
Intercarrier interference due to Phase Noise (2004)
Denis Petrovic, Wolfgang Rave, Gerhard Fettweis
Abstract — In this paper we provide an analysis of the intercarrier interference (ICI) due to phase noise in OFDM systems and present an algorithm for its suppression. We examine the general case...
Iterative Correction of Phase Noise in Multicarrier Modulation (2004)
Wolfgang Rave, Denis Petrovic, Gerhard Fettweis
Abstract — We investigate a phase noise suppression algorithm which estimates the Fourier components of the phase noise process to eliminate intercarrier interference in addition to standard common...
Performance Analysis for Blind I/Q Imbalance Compensation (2004)
Marcus Windisch, Gerhard Fettweis
A novel blind I/Q imbalance parameter estimation and compensation scheme for low-IF receivers, which was previously proposed by the authors, is analytically analyzed in this paper. As an outcome, we...
Overloaded TDD-CDMA cells with multiuser transmission (2004)
Ralf Irmer, René Habendorf, Wolfgang Rave, Gerhard Fettweis
Abstract — The number of supportable users in the TDD-CDMA downlink is usually limited by multiple-access interference and by the limited number of available orthogonal spreading codes. By using...
Analysis of Node Energy Consumption in Sensor Networks (2004)
Katja Schwieger, Heinrich Nuszkowski, Gerhard Fettweis
The energy consumption of network nodes in low data rate networks is analyzed using Markov chains and signal flow graphs. It allows for a comprehensive OSI-layer analysis, taking into account...
Nonlinear chip-level multiuser transmission for TDD-CDMA in frequency-selective MIMO channels (2004)
Ralf Irmer, René Habendorf, Wolfgang Rave, Gerhard Fettweis
Multiuser Transmission (MUT), the counterpart of Multiuser Detection (MUD) in the transmitter, can substantially enhance the performance of the CDMA downlink in frequency-selective channels. Besides...
Efficient tracking of eigenspaces and its application to mimo-systems (2003)
Frank Schäfer, Matthias Stege, Clemens Michalke, Gerhard Fettweis
To achieve high performance for MIMO wireless systems with multiple transmit and receive antennas a detailed understanding of the characteristics of the Eigenspace of the channel is essential. It...
Computation of forward and inverse MDCT using Clenshaw’s recurrence formula (2003)
Vladimir Nikolajevic, Student Member, Gerhard Fettweis, Senior Member
Abstract—The forward and inverse modified discrete cosine transform (MDCT) are two of the most computational intensive operations in the MPEG audio coding standard. In this paper, we used...
Joint signal precoding in the downlink of spread-spectrum systems (2003)
André Noll Barreto, Gerhard Fettweis, Senior Member
Abstract—The downlink capacity tends to be the limiting factor in future communications systems. In this paper, we propose two schemes for the downlink of code-division multiple-access systems that...
Performannce Degradation of Coded-OFDM due to Phase Noise (2003)
Denis Petrovic, Wolfgang Rave, Gerhard Fettweis
Abstract — In this paper we investigate the effect of phase noise on coded OFDM transmission with parameters typical for present OFDM based WLAN standards. Two different scenarios are compared,...
Relaying in CDMA Networks: Pathloss Reduction and Transmit Power Savings (2003)
Patrick Herhold, Wolfgang Rave, Gerhard Fettweis
Abstract — Relaying has recently emerged as a field of growing interest for wireless systems. The use of intermediate nodes for relaying information from a source to its destination promises...
The effects of aperture jitter and clock jitter in wideband ADCs (2003)
Michael Löhning, Gerhard Fettweis
Designing leading-edge systems (e.g., communications systems) requires knowledge about the technological limits. Jitter is the limiting effect in ADCs with a digitization bandwidth between 1 MHz and...
Multistratum-Permutation Codes for MIMO Communication (2003)
Matthias Stege, Student Member, Gerhard Fettweis, Senior Member
Multiple-input--multiple-output (MIMO) systems offer much capacity gain over single antenna approaches. The recently proposed multistratum space--time code (MSSTC) is such a MIMO-scheme among many...
MOUSE: A Shortcut From Matlab Source to SIMD DSP Assembly Code (2003)
Gordon Cichon, Gerhard Fettweis
This article presents a novel design flow called MOUSE for the effective development of digital signal processing systems in terms of development time, performance and power consumption. It uses a...
On the Performance of Cooperative Diversity Protocols in Practical Wireless Systems (2003)
Ernesto Zimmermann, Patrick Herhold, Gerhard Fettweis
The concepts of cooperative diversity promise to offer the benefits of spatial diversity gains to handheld wireless devices with single antennas. The information-theoretic bounds that have been...
Efficient Tracking of Eigenspaces and its Application to Eigenbeamforming (2003)
Clemens Michalke, Matthias Stege, Frank Schäfer, Gerhard Fettweis
To achieve high performance for MIMO wireless systems with multiple transmit and receive antennas a detailed understanding of the characteristics of the Eigenspace of the channel is essential. It...
MOUSE: A Shortcut From Matlab Source to SIMD DSP Assembly Code (2003)
Gordon Cichon, Gerhard Fettweis
This article presents a novel design flow called MOUSE for the effective development of digital signal processing systems in terms of development time, performance and power consumption. It uses a...
Phase Noise Suppression in OFDM Using a Kalman Filter (2003)
Denis Petrovic, Wolfgang Rave, Gerhard Fettweis
The performance of an OFDM system can be strongly degraded by the presence of random phase noise especially if a system design targets high data rates at high carrier frequencies. Phase noise causes...
Phase Noise Suppression in OFDM Including (2003)
Intercarrier Interference Denis, Denis Petrovic, Wolfgang Rave, Gerhard Fettweis
In order to suppress the influence of phase noise in OFDM communications systems, the correction of the common phase error (CPE) does not suffice always, especially when high data rates are required....
Minimum BER Transmission for TDD-CDMA in Freguency-Selective Channels (2003)
Ralf Irmer, Wolfgang Rave, Gerhard Fettweis
Abstract — A novel approach to Multiuser Transmission (MUT) for the CDMA downlink in frequency-selective channels is proposed. The key idea is to minimize the BER at the receivers directly by...
Nonlinear multiuser transmission using multiple antennas for TDD-CDMA (2003)
Ralf Irmer, René Habendorf, Wolfgang Rave, Gerhard Fettweis
Abstract — Multiuser Transmission (MUT), the counterpart of Multiuser Detection(MUD) in the transmitter, can substantially enhance the performance of the CDMA downlink in frequencyselective...
Recursive Filtering on SIMD Architectures (2003)
Rainer Schaffer, Michaell Hosemann, Michael Hosemann, Renate Merker, Gerhard Fettweis
Recursive filters are used frequently in digital signal processing. They can be implemented in dedicated hardware or in software on a digital signal processor (DSP). Software solutions often are...
Transmit Diversity for Frequency Selective Channels (2002)
Uwe Ringel, Ralf Irmer, Gerhard Fettweis
Abstract—Multipath propagation and fading are typical characteristics of wireless communication channels. Simultaneously, they are also the most limiting factors for high speed data rates. This...
Ferry P. Wathan, Ralf Irmer, Gerhard Fettweis
The capacity of CDMA-based systems, for instance UMTS, is interference limited. The downlink (DL) is expected to carry much more traffic than in the uplink (UL) for multimedia applications services....
Phase Noise Influence on Bit Error Rate, Cut-off Rate and Capacity (2002)
Denis Petrovic, Wolfgang Rave, Gerhard Fettweis
Abstract — The performance of a bit-interleaved coded OFDM system disturbed by phase noise is investigated. The sensitivity is calculated as a function of the 3 dB phase noise bandwidth for several...
Reduced and differential parallel interference cancellation for CDMA systems (2002)
Achim Nahler, Associate Member, Ralf Irmer, Student Member, Gerhard Fettweis, Senior Member
Abstract—Since code division multiple access systems in multipath environments suffer from multiple access interference (MAI), multiuser detection schemes should be used in the receivers. Parallel...
Energy Savings with Appropriate Interconnection Networks in Parallel DSP (2002)
Thorsten Dräger, Gerhard Fettweis
This paper presents an instruction level power model for a very long instructions word (VLIW) single instruction multiple data (SIMD) digital signal processor (DSP). We show that power consuming...
MISO Concepts for frequency-selective channels (2002)
In order to limit interference and increase system capacity in CDMA systems, transmitted power required to achieve a certain performance should be as low as possible. Usually, receivers are designed...
Matlab Based Codesign Framework for Wireless Broadband Communication DSPs (2001)
Volker Aue, Johannes Kneip, Matthias Weiss, Michael Bolle, Gerhard Fettweis
We provide an overview of a novel MATLAB TM based Hardware-Software design flow that has been applied to the design of a platform based SoC for the HiperLAN/2 and IEEE 802.11a wideband wireless...
New Recursive Algorithms for the Forward and Inverse MDCT (2001)
Vladimir Nikolajevic, Gerhard Fettweis
Abstract ⎯ Forward and inverse MDCT are two of the most computational intensive operations in the MPEG audio coding standard. In this paper we derive sinusoidal recursive formulas for transforming...
New Recursive Algorithms for the Forward and Inverse MDCT (2001)
Vladimir Nikolajevic, Gerhard Fettweis
Abstract ⎯ Forward and inverse MDCT are two of the most computational intensive operations in the MPEG audio coding standard. In this paper we derive sinusoidal recursive formulas for transforming...
Channel estimation using longterm spatial channel characteristics (2001)
Matthias Stege, Tom Ruprich, Marcus Bronzel, Gerhard Fettweis
Communications systems using CDMA-techniques are in general limited by interference. Therefore, the number of users within a cell as well as their data rates are limited. The use of multiple antenna...
Ralf Irmer, Achim Nahler, Gerhard Fettweis
Since CDMA systems in multipath environments suffer from multiple access interference (MAI) multiuser detection (MUD) schemes are used in the receivers. Parallel Interference Cancellation (PIC) is an...
Transmitter Precoding for Spread-Spectrum Signals in Frequency-Selective Fading Channels (2001)
Ralf Irmer, André N. Barreto, Gerhard Fettweis
Spread-spectrum systems are used to transmit over frequency selective fading channels. The RAKE receiver is a well-established technique to exploit the multipath diversity. However, if the channel...
Interference Reduction in Single Hop Relay Networks (2001)
Marcus Bronzel Wolfgang, Wolfgang Rave, Patrick Herhold, Gerhard Fettweis
The purpose of this paper is to determine the possible capacity increase in single hop relay networks, where mobile stations are enabled to serve as additional access points for other terminals. The...
Digital Down Conversion in Software Radio Terminals (2000)
Michael Löhning, Tim Hentschel, Gerhard Fettweis
The idea of software radio requires an expansion of digital signal processing towards the antenna. Hence, for converting the received signal to baseband, the need of efficient high speed digital down...
Matthias Stege, Jens Jelitto, Marcus Bronzel, Gerhard Fettweis
Space-time receivers for wireless communication systems offer the possibility to have both TX- and RX-antennas. For a realistic simulation of such systems, a multiple input multiple output (MIMO)...
Digital Down Conversion in Software Radio Terminals (2000)
Michael Löhning, Tim Hentschel, Gerhard Fettweis
The idea of software radio requires an expansion of digital signal processing towards the antenna. Hence, for converting the received signal to baseband, the need of efficient high speed digital down...
Time-Varying Recursive Filters For Decimation (2000)
And Interpolation Tim, Tim Hentschel, Gerhard Fettweis
Decimation and interpolation require filtering. In order to reduce the hardware effort, FIR filters with linear phase are implemented as polyphase filters often. Still, the number of coefficients...
A Vector Channel Model with Stochastic Fading Simulation (1999)
Jens Jelitto, Matthias Stege, Michael Löhning, Marcus Bronzel, Gerhard Fettweis
Abstract — The simulation of wireless communication systems with multiple antennas requires a spatial channel model which reasonably characterizes the space and time variant effects of the mobile...
The digital front-end of software radio terminals (1999)
Tim Hentschel, Matthias Henker, Gerhard Fettweis
When expanding digital signal processing of mobile communications terminals toward the antenna while making the terminal more wideband in order to be able to cope with different mobile communications...
Jörg Fischer, Jürgen Deissner, Gerhard Fettweis, Dietrich Hunold, Ralf Lehnert, Mathias Schweigel, ...
The process of developing and enhancing a mobile radio system is a very ambitious task due to the inherent complexity and the manifold dynamics of such networks. Essentially, the problem leads to an...
Object-Oriented Modeling Of A Generic Mobile Radio System For Dynamic System Simulation (1999)
Jörg Fischer, Jürgen Deissner, Gerhard Fettweis, Dietrich Hunold, Ralf Lehnert, Mathias Schweigel, ...
The process of developing and enhancing a mobile radio system is a very ambitious task due to the inherent complexity and the manifold dynamics of such networks. Essentially, the problem leads to an...
AD Conversion and Channelization for Multi-Mode Terminals (1998)
Tim Hentschel, Gerhard Fettweis
This paper presents an architecture for multi-mode terminals, strictly speaking multi-mode receivers, exploiting IF sampling with Sigma-Delta ADCs. It is shown that Sigma-Delta ADCs are not only an...
Interference analysis of a Total Frequency Hopping (1998)
Jürgen Deißner, André Noll Barreto, Ulrich Barth, Gerhard Fettweis
In this paper we present an interference analysis which reveals capacity reserves for a hierarchical GSM radio network. In the investigated concept a low-power Cordless Telephony System reuses the...
Breaking New Grounds Over 3000 M MAC/s: A Broadband Mobile Multimedia Modem DSP (1998)
Gerhard Fettweis, M. Weiss, W. Drescher, U. Walther, F. Engel, S. Kobayashi, ...
Future DSP architectures need to be developed for paving the way into a generation of high scale signal processing power, i.e. greater than 1000M MAC/s (multiply accumulate per second). This can only...
An Architectural Study of a Digital Signal Processor for Block Codes (1998)
Wolfram Drescher, Menno Mennenga, Gerhard Fettweis
This paper examines architectural issues for a domain specific digital signal processor (DS-DSP) which is capable of fast decoding of block codes. In real time systems it was not possible before to...
DSP cores for mobile communications: where are we going (1997)
Digital signal processors (DSPs) have become a key component for the design of communications ICs. Application customization leads to key market advantages but also to enormous problems of having too...
Mobile Software Telecommunications (1997)
Gerhard Fettweis, Raymond Steele
Abstract- Telecommunications is shifting from anytime, anywhere to anytime, anywhere, any way, any speed, whatever. This requires a revolution in flexibility by going from today’s pre-defined...
VLSI Architecture for Datapath Integration of Arithmetic over (1997)
Wolfram Drescher, Kay Bachmann, Gerhard Fettweis
This paper examines the implementation of Finite Field arithmetic, i.e. multiplication, division, and exponentiation, for any standard basis GF(2 m) with m≤8 on a DSP datapath. We introduce an...
VLSI Architecture For Non-Sequential Inversion Over GF(2 m ) Using The Euclidean Algorithm (1997)
Wolfram Drescher, Kay Bachmann, Gerhard Fettweis
ABSTRACT 2
Wolfram Drescher, Kay Bachmann, Gerhard Fettweis
This paper examines the implementation of Finite Field arithmetic, i.e. multiplication, division, and exponentiation, for any standard basis GF(2 m ) with m8 on a DSP datapath. We introduce an...
VLSI Architecture for Multiplication in GF(2m ) for Application Tailored Signal Processors (1996)
Wolfram Drescher, Gerhard Fettweis
Abstract- Finite Field Arithmetic plays an important role in coding theory, cryptography and their applications. Several hardware solutions using Finite Field Arithmetic have already been developed...
A CMOS IC for Gb/s viterbi decoding: system design and VLSI implementation (1996)
Herbert Dawid, Student Member, Gerhard Fettweis, Heinrich Meyr
used in communication systems for decoding and equalization. The achievable speed of conventional Viterbi decoders (VD’s) is limited by the inherent nonlinear add-compare-select (ACS) recursion....
Results on multi-carrier CDMA receiver design (1995)
Ahmad Shaikh Bahai, Gerhard Fettweis
Abstract: Spread spectrum techniques require accurate timing and &er synchronization and usually encounter performance losp under significant Doppler spread condition. Applying the malti-aurier...
Multi-Carrier CDMA In Indoor Wireless Radio Networks (1993)
Nathan Yee, Jean-paul Linnartz, Gerhard Fettweis
This paper examines a novel digital modulation/multiple access technique called Multi-Carrier Code Division Multiple Access (MC-CDMA) where each data symbol is transmitted at multiple narrowband...
Multi-Carrier CDMA in Indoor Wireless Radio Networks (1993)
Nathan Yee, Jean-paul Linnartz, Gerhard Fettweis
This paper examines a novel digital modulation/multiple access technique called Multi-Carrier Code Division Multiple Access (MC-CDMA) where each data symbol is transmitted at multiple narrowband...
Parallelisierung des Viterbi-Decoders :$bAlgorithmus und VLSI-Architektur / (1990)
Fettweis, Gerhard., Verein Deutscher Ingenieure.
Thesis--TH Aachen.
An Architectural Study Of A Digital Signal Processor For Block Codes
Wolfram Drescher, Menno Mennenga, Gerhard Fettweis
This paper examines architectural issues for a domain specific digital signal processor (DS-DSP) which is capable of fast decoding of block codes. In real time systems it was not possible before to...
SUBMITTED TO IEEE TRANS. INFORM. THEORY 1 Analysis of a Mixed Strategy for Multiple Relay Networks
Peter Rost, Student Member, Gerhard Fettweis, Senior Member
In their landmark paper Cover and El Gamal proposed different coding strategies for the relay channel with a single relay supporting a communication pair. These strategies are the decode-and-forward...