Christian Hoene

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The design and simulation of coding schemes, Medium Access Control (MAC), and link-layer protocols for future industrial wireless local area networks can be supported by some understanding of the statistical properties of the bit error patterns delivered by a wireless link (which is an ensemble of transmitter, channel, receiver, modems). We present results(More)
This technical report explores the degree of accuracy to which the propagation delay of WLAN packets can be measured using today’s commercial, inexpensive equipment. The aim is to determine the distance between two wireless nodes for location sensing applications. We conducted experiments and measured the time difference between sending a data packet and(More)
This thesis presents algorithms to enhance the efficiency of packetized, interactive speech communication over wireless networks. The results achieved are the following: We present an improved approach to assess the quality of voice transmissions in IP-based communication networks. We combined the ITU E-Model, the ITU PESQ algorithm, and various codec and(More)
In this paper we present an algorithm that measures the round trip times of IEEE 802.11 MAC packets in order to trilaterate WLAN nodes. We show that if we use packet sequences (e.g., RTS, CTS, DATA and ACK) instead of packet pairs (e.g., DATA and ACK), the TOA measurements can be implemented more easily and a higher observation rate can be achieved. In(More)
Quality models predict the perceptual quality of services as they calculate subjective ratings from measured parameters. In this article, we present a new quality model that evaluates VoIP telephone calls. In addition to packet loss rate, coding mode and delay, it takes into account the impairments due to changes in the transmission configuration (e.g.(More)
The performance of unreliable voice transmission (Voice over IP) over wireless links is measured not by the throughput but by the perceptual speech quality. The speech quality is impaired by packet losses, which are common on wireless links, and by high transmission delays. In this paper, we describe the design and implementation of a novel Speech Property(More)