Christoph Scholz

Bluetooth scatternets: an enhanced adaptive scheduling scheme

The vision of ad-hoc networking with Bluetooth includes the concept of devices participating in multiple piconets and thereby forming a scatternet. However, the details of scatternet support for Bluetooth are not specified yet. This paper presents a scheme for Bluetooth scatternet operation that adapts to varying traffic patterns. Being based on sniff mode, it does not require substantial modification of the current Bluetooth specification and may thus be incorporated into currently available Bluetooth products. We present simulation results that confirm the applicability of our approach to realistic scenarios.

Adaptive scatternet support for Bluetooth using sniff mode

Future applications of Bluetooth are likely to include ad-hoc networking. Therefore, it is desirable to interconnect multiple Bluetooth piconets to form a scatternet. Up to now, there is no extensive proposal for scatternet support available. We present and analyze an adaptive scheme for scatternet scheduling that is based on the sniff mode and thus does not require substantial modification of the current Bluetooth specification. The suitability of our approach is shown by first simulation results.

A worst-case model for co-channel interference in the Bluetooth wireless system

This paper presents a model for the expected throughput in a Bluetooth network in presence of a number of other Bluetooth networks that cause radio interference. The analysis considers unidirectional traffic and makes worst-case assumptions on the effect of radio interference. In order to verify the model, simulation results are presented. The results from this work may be very useful when designing ad-hoc networking functionality for future versions of Bluetooth.

Integration of 3G Protocols into the Linux Kernel to Enable the Use of Generic Bearers

The General Packet Radio Service (GPRS) is widely deployed in second and third generation mobile cellular networks. Special benefits of GPRS are mobility management as well as support of authentication, authorization, and accounting (AAA). However, the data rates of GPRS are low and the price is high, compared to wired networks or Wireless LAN. Furthermore, Wireless LAN hotspots are starting to sprout. While Wireless LAN in fact offers high data rates, it lacks a standard for billing and roaming. One solution is to combine both technologies, GPRS and Wireless LAN. The resulting system would offer Wireless LAN’s higher bandwidth, while keeping GPRS’ sophisticated billing and roaming support. Wireless inter-system roaming supporting seamless handovers could be a benefit beyond. In this paper we present the first step of combining Wireless LAN and GPRS, by integrating the GPRS protocol stack into the Linux kernel. In addition to the integration we present evaluation results and improvements, concerning the choice of GPRS parameters.