Reliable Download Delivery in a Terrestrial DAB Network

Reliable file transfer is important in broadcast networks. In this paper, we have investigated if it is useful to extend the DAB standard with Fountain codes. To evaluate this, results from measurements in a live Single Frequency Network (SFN) were used. Our results show that the existing error correction algorithms provide already reliable file delivery, so there is no need to extend the DAB standard

Modulation-Index Estimation in a Combined CPM/OFDM Receiver

In this paper we develop a blind modulation-index estimator for\ud a combined CPM/OFDMReceiver. The performance of the estimator\ud in an AWGN channel is assessed by simulation and analysis\ud and its suitability for our receiver is established

A (Simplified) Bluetooth Maximum a Posteriori Probability (Map) Receiver

In our software-defined radio project, we aim at combining two standards luetooth and HIPERLAN/2. The HIPERLAN/2 receiver requires more computational power than Bluetooth. We choose to use this computational power also for Bluetooth and look for more advanced demodulation algorithms such as a maximum a posteriori probability (MAP) receiver. The paper discusses a simplified MAP receiver for Bluetooth GFSK signals. Laurent decomposition provides an orthogonal vector space for the MAP receiver. As the first Laurent waveform contains the most energy, we have used only this waveform for our (simplified) MAP receiver. This receiver requires a E/sub b//N/sub 0/ of about 11 dB for a BER of 10/sup -3/, required by the Bluetooth standard. This value is about 6 dB better than single bit demodulators. This performance is only met if the receiver has exact knowledge of the modulation index

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

The Front end of Software-Defined Radio: Possibilities and Challenges

The use of mobile telephony has shown a spectacular\ud growth in the last 10 years. A side effect of this rapid\ud growth is an excess of mobile system standards. Therefore,\ud the Software-Defined-Radio (SDR) concept is emerging as\ud a potential pragmatic solution: it aims to build flexible radio\ud systems, which are multi-service, multi-standard, multiband,\ud re-configurable and re-programmable, by software.\ud First, this paper presents a global overview of SDR.\ud Furthermore, it discusses several front-end architectures of\ud SDR. The goal of this project is to generate knowledge about\ud designing part of the functionality of SDR, implemented by\ud rapid prototyping strategies. The focus is on the front end\ud of SDR. The technological roadmap is taken into account to\ud evaluate several architectures

Undetected error probability for data services in a terrestrial DAB single frequency network

DAB (Digital Audio Broadcasting) is the European successor of FM radio. Besides audio services, other services such as traffic information can be provided.\ud An important parameter for data services is the probability of non-recognized or undetected errors in the system. To derive this probability, we propose a bound for the undetected error probability in CRC codes. In addition, results from measurements of a Single Frequency Network (SFN) in Amsterdam were used, where the University of Twente conducted a DAB field trial. The proposed error bound is compared with other error bounds from literature and the results are validated by simulations. Although the proposed bound is less tight than existing bounds, it requires no additional information about the CRC code such\ud as the weight distribution. Moreover, the DAB standard has been extended last year by an Enhanced Packet Mode (EPM) which provides extra protection for data services. An undetected error probability for this mode is also derived. In a realistic user scenario of 10 million users, a 8 kbit/s EPM sub channel can be considered as a system without any undetected errors (Pud = 6 · 10−40). On\ud the other hand, in a normal data sub channel, only 110 packets with undetected errors are received on average each year in the whole system (Pud = 5 · 10−13)

MIMO System Setup and Parameter Estimation

There is a rat race in wireless communication to achieve higher spectral efficiency. One technique to achieve this is the use of multiple antenna systems i.e. MIMO systems. In this paper we describe a wireless 4x4 Multiple Input Multiple Output (MIMO) testbed in the 2.2 GHz band including results from live experiments. MIMO systems have several advantages compared to SISO (Single Input Single Output) systems. The most important ones are higher reliability and/or higher throughput per Herz. In this testbed we used the 802.11a OFDM Wireless LAN standard as a basis for the MIMO system. The experiments have been conducted at 2.2 GHz carrier using 5 MHz bandwidth. These can be divided into several subjects: antenna spacing experiments, effects for increasing antennas, AD accuracy and performance for different antenna topologies. Moreover, the performance of the Zero Forcing (ZF), Minimum Mean Square Error (MMSE) and Vertical Bell labs LAyered Space Time (VBLAST) have been evaluated

A combined receiver front-end for Bluetooth and HiperLAN/2

A Software Defined Radio is a radio receiver that is reconfigurable by software. This reconfigurability leads to flexibility that can be used to offer more functionality to the user. Also, because common reconfigurable hardware can be used for very diverse radio interfaces, production and logistics can be faster and cheaper. In our Software Defined Radio project we aim at a receiver that is able to receive signals of any contemporary or future radio standard. However, because we need tangible specifications in order to design, we have chosen to implement a combination of two rather different standards: Bluetooth and HiperLAN/2. Both the analogue and the digital/software parts are included in the design. A CMOS integrated wideband analogue front-end containing a low noise amplifier, downconversion mixers and filters has been designed. This front-end\ud is connected to a PCB that contains two analogue-to-digital convertors and a sample rate convertor (SRC). The output of this board is connected to a standard PC through a digital I/O board with PCI bus. Software on this PC performs the demodulation.\ud We conclude that an analog wide-band front-end with a flexible SRC combined with appropriate software on an inherently flexible PC forms a promising architecture for Software Defined Radio

Timing Metrics of Joint Timing and Carrier-Frequency Offset Estimation Algorithms for TDD-based OFDM systems

In joint timing and carrier offset estimation algorithms for Time Division Duplexing (TDD) OFDM systems, different timing metrics are proposed to determine the beginning of a burst or symbol. In this contribution we investigated the different timing metrics in order to establish their impact on the joint time and carrier-frequency offset estimation