Adaptive OFDM System Design For Cognitive Radio

Recently, Cognitive Radio has been proposed as a promising technology to improve spectrum utilization. A highly flexible OFDM system is considered to be a good candidate for the Cognitive Radio baseband processing where individual carriers can be switched off for frequencies occupied by a licensed user. In order to support such an adaptive OFDM system, we propose a Multiprocessor System-on-Chip (MPSoC) architecture which can be dynamically reconfigured. However, the complexity and flexibility of the baseband processing makes the MPSoC design a difficult task. This paper presents a design technology for mapping flexible OFDM baseband for Cognitive Radio on a multiprocessor System-on-Chip (MPSoC)

A Real-Time GPP Software-Defined Radio Testbed for the Physical Layer of Wireless Standards

We present our contribution to the general-purpose-processor-(GPP)-based radio. We describe a baseband software-defined radio testbed for the physical layer of wireless LAN standards. All physical layer functions have been successfully mapped on a Pentium 4 processor that performs these functions in real time. The testbed consists of a transmitter PC with a DAC board and a receiver PC with an ADC board. In our project, we have implemented two different types of standards on this testbed, a continuous-phase-modulation-based standard, Bluetooth, and an OFDM-based standard, HiperLAN/2. However, our testbed can easily be extended to other standards, because the only limitation in our testbed is the maximal channel bandwidth of 20 MHz and of course the processing capabilities of the used PC. The transmitter functions require at most 714 M cycles per second and the receiver functions need 1225 M cycles per second on a Pentium 4 processor. In addition, baseband experiments have been carried out successfully

Mapping Wireless Communication Algorithms onto a Reconfigurable Architecture

Future mobile communication systems have to be flexible while adapting to environmental conditions and user demands. These systems also have to be energy-efficient as they are used in battery-operated terminals. We expect that heterogeneous reconfigurable hardware can overcome the contradicting requirements in flexibility, energy-efficiency and performance. A coarse-grain reconfigurable processor, called MONTIUM, is presented. An overview of a wireless LAN communication system, HiperLAN/2, and a Bluetooth communication system will be given. Possible implementations of these systems in heterogeneous reconfigurable hardware are discussed. Performance figures of the implemented HiperLAN/2 baseband processing in the MONTIUM architecture are presented. The required performance can be obtained at low clock frequencies with small configuration overhead. The flexibility of the MONTIUM is shown, as the baseband processing of both HiperLAN/2 and Bluetooth is implemented on the same architecture