Marcus Bronzel

A multiple input-multiple output channel model for simulation of Tx- and Rx-diversity wireless systems

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) spatial channel model is required which reasonably characterizes the space- and time-variant effects of the mobile radio channel. This paper describes a space-time vector channel model with realistic fading simulation for different scenarios. Mutual correlation between the fading coefficients is considered. This allows an estimation of the diversity gain, that can be achieved with space-time receivers in different scenarios.

Synchronous Transfer Architecture (STA)

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 reconfigurable hardware. STA processors are modeled using a common machine description suitable for both compiler and core generator. The core generator is able to generate models in Lisa, System-C, and VHDL. A special emphasis is placed on the good synthesis of the generated VHDL model.

A closed solution for an integrated broadband mobile system (IBMS)

Most current development strategies for future mobile systems are concerned with partial solutions only regarding the mobility-bit rate problem. In this paper the basic ideas of the integrated broadband mobile system (IBMS), supporting in a unified way a variety of communication classes ranging from high mobility with low data rates towards quasi-stationarity at high data rates, are presented. The key feature of this proposal is a closed system approach for both outdoor and indoor environment. Essential is the use of a single common, low bit-rate, generally available signalling channel for negotiation of the required service class or supporting the fallback to a lower service class if necessary. In the outdoor area, the use of smart antennas with strongly sectorized coverage will support high bit rates on behalf of reduced mobility speed, while simultaneously assuring efficient use of frequency spectrum. The same signalling channel will also be used to coordinate possible change of the mobile terminal to and forth between the outdoor provision and space limited indoor domains, operating on the picocell principle. Mobile terminals can be designed in a modular way to support all, or only some lower, bit rates. IBMS allows for an evolutionary extension starting from the infrastructure of todays digital cellular systems towards a multimedia and multiservice support of future universal personal communications using an ATM based communication backbone. IBMS is a joint research effort of Dresden University of Technology, Ilmenau University of Technology, Technical University of Berlin, and the Heinrich-Heaz-Institute Berlin sponsored by the German federal ministry of education, science, research and technology (BMBF) within the project line ATMmobil.

An integrated FSK-signaling scheme for OFDM-based advanced cellular radio

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 terminal (MT). In order to increase battery life and allow low-cost mobile equipment to be effectively integrated in such a broadband system we propose the use of a separate low-rate signaling channel (SSC) on the physical layer. This additional channel has the primary function of power saving. For this purpose it takes on connection and mobility control functions as well as further tasks on broadcasting and synchronization. A new concept of a broadband TDMA system is presented, incorporating OFDM for the physical high rate data channel (D-channel) and CPFSK modulation with non-coherent detection for the low-rate SSC, whereby both channels are separated in frequency. Modem and system design issues are discussed and evaluated by simulation.

Compiler Scheduling for STA-Processors

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 proposed scheduling approach is based on informed, deterministic algorithms that can be implemented run-time efficiently. Although the presented compiler prototype does not generate optimized code, it provides a proof-of-concept of the feasibility of the proposed compiler architecture.

From Smart Antennas to Reduced Dimension Space-Time Processing

The Integrated Broadband Mobile System (IBMS) is a concept for future wireless communications systems that has been developed in order to integrate heterogeneous services and applications into a common framework. Smart antennas are used as the enabling technology to support high and variable data rates. A hardware testbed was developed for the investigation of algorithms and real-time aspects of smart antennas, which uses separate stages for processing of spatial and temporal information. Research results indicate that the system performance can be enhanced using a space-time processor (STP) which carries out spatial and temporal information processing jointly. This paper reviews the IBMS physical layer and presents the results obtained with the smart antenna demonstrator. A new STP concept with reduced signal dimension by means of the KarhunenLoeve-Transformation (KLT) is introduced and analyzed. Übersicht Das Integrierte Breitbandbandige Mobilkommunikations-System (IBMS) ist ein Konzept für die zukünftige Mobilkommunikation, welches durch Einsatz verschiedener Schlüsseltechnologien die Integration verschiedenartiger Dienste in ein gemeinsames Gesamtsystem ermöglicht. Zur Bereitstellung hoher und variabler Datenraten werden in diesem System intelligente Antennen eingesetzt. Algorithmen zur adaptiven Strahlformung wurden im Hinblick auf ihre Leistungsfähigkeit unter Echtzeitbedingungen untersucht und auf einem Hardware-Testbed demonstriert, das räumliche und zeitliche Informationen getrennt verarbeitet. Darüber hinaus wurden kombinierte Raum-Zeit-Verarbeitungsansätze analysiert, welche der getrennten räumlichen und zeitlichen Verarbeitung in vielen Bereichen überlegen sind. In dieser Arbeit werden die wichtigsten Parameter der physikalischen Schicht des IBMS zusammengefaßt und der .IBMS Smart Antenna Demonstrator* vorgestellt. Darüber hinaus wird ein neuartiges Konzept zur dimensionsreduzierten Raum-Zeit-Verarbeitung vorgestellt und analysiert, welches auf der Karhunen-Loeve-Transformation (KLT) beruht. Für die Dokumentation Strahlformung / Raum-Zeit-Signalverarbeitung / Low-rank modeling / Karhunen-Loeve-Transformation / IBMS Frequenz 55(2001) 5-6

Implementing a receiver for terrestrial digital video broadcasting in software on an application-specific DSP

Terrestrial digital video broadcasting (DVB-T) is currently being introduced in many European countries and planned to supplement or replace current analogue broadcasting schemes in a large part of the world. It is also considered as an additional downlink medium for third generation UMTS mobile telephones, where a special variant, DVB-H, is under development. Current DVB-T receivers still are built upon dedicated application specific integrated circuits (ASIC). However, designing ASIC is a tedious and expensive task. We show that it is possible to implement a DVB-T receiver in software on an application-specific digital signal processor (AS-DSP). We analyze the computational requirements of a DVB-T receiver and investigate its potential for parallelization. Further, we present our AS-DSP, the M5-DSP, which is based on a novel architecture and design methodology, and report on implementing the core algorithms of a DVB-T receiver on it.

On the performance of space-time block codes

Space-time block codes (STBC), that have been introduced by S.M. Alamouti (IEEE Journal on Selected Areas in Communication, vol.16, no.8, p.1451-8, 1998) and V. (IEEE-info, vol.45, 1999), are now considered in the current 3GPP standard as one method to achieve spatial diversity. While the performance of space-time block codes has been subject of extensive research (see Parkvall, S. et al, 2000; Correia, A. et al., 1999; Tharokh et al., 1999), the impact of channel estimation errors and closed loop power control on the performance of STBC remain open for further research. The performance of STBC with imperfect channel estimates and closed loop power control is analyzed for flat fading channels as well as for multipath channels.

Generated DSP Cores for Implementation of an OFDM Communication System

Application tailored signal processors fill the gap between ASICs and general purpose DSPs. Single Instruction Multiple Data(SIMD) Signal Processors offer high computational power with low control overhead. This paper describes the development of a multi-processor OFDM-System x using automatically generated SIMD-DSP Cores. The focus of this case of study was the test of our integrated design flow which is based on our core generation tool. We show how with our design methodology we reduce the design cycle in comparsion with other HW/SW Co-design tools and traditional design flows.

Integrated broadband mobile system (IBMS) featuring smart antennas

IBMS is a concept for future mobile communication systems to provide a large range of data rates with different degrees of mobility. The integration of heterogeneous services and communication systems requires a common Network Access and Connectivity CHannel (NACCH) for basic signaling to provide permanent network access. Smart Antennas are utilized to adaptively enable a trade-off between mobility and data rate.