TKN Technical Reports Series

ii Message from the editors Wireless sensor networks are certainly one of the most quickly paced, fastest growing areas in networking research of the recent time. They encompass a wide range of different topics, and are by their very nature quite interdisciplinary: protocol research depends much more strongly on hardware properties than it does in conventional networks, application design is related to how spatial and temporal coding can be designed, and distributed algorithms are influenced by characteristics of the wireless channel. To enable a quick information exchange and to encourage a lively discussion about ongoing, promising work in this field, we decided early on in the organization phase of the 1st European Workshop of Wireless Sensor Networks (EWSN 2004) to include a work-inprogress session. This session was run as a poster session, which we believe is perhaps the best possible form to engage the audience in in-detail discussions about technical contents – which is particularly important for research work that is still in a relatively early phase and where feedback from peer researchers is most fruitful

TKN Technical Reports Series

As the IEEE 802.11 based internet access is becoming ubiquitos available it is excepted that WLAN will be applied for telephony. In this paper we follow the objective to access whether WLAN allows calls at toll quality. Toll quality is the minimal quality of PSTN-based telephons calls. With simulations we evaluate the MAC protocol modes distribution coordination function (DCF), enhanced DCF (EDCF) and contention free bursting (CFB). We have verifed our simulation model by cross-checking it with the results of other researchers. We present quantitative results of the perceptual quality and enhance the precision of performance evaluation on Voice over Wifi systems