The Austrian Amateur Radio Society (ÖVSV) establsihes a new digital transmission procedure allowing high speed data communication in Sub-GHz Frequency bands. Requirements are to use a wideband transmission mode to support state of the art bandwidth for each user, and to enable multiple users at the same time to connect to a base station providing access to HAMNET. The implementation is be based on the concept of a software defined radio using commercial available hardware and open source software. This addresses and motivates a larger community of developers and radio amateurs. Hardware and software are designed as kit, the RPX-100, which allows a modular use and supports all possible Sub-GHz frequency bands. The Institute of Telecommunications of TU-Wien has successfully requested permit to test operation of such a new digital communication system at 52-54MHz in the 6m band. Multi user access is achieved by using OFDMA as channel access methodology based on IEEE 802.22 (WRAN) standard.
A Wifi interface connects the RPX-100 with the LAN for remote operation, debugging and programming. The
software id written C++ using liquid-dsp libraries. The concpet of the WRAN software uses the IEEE
802.22 frame structure for prototyping to make use of super
frames and preambles for cognitive channel management, which allows a dynamic resource allocation between base
stations, but also between multiple users at one base station.
Orthogonal Frequency Division Multiple Access (OFDMA) is used in the upper layers, as Modulation techniques QPSK, 16-QAM and 64-QAM is supported.
The software will support a connection-oriented MAC layer with cognitive functionality for dynamic and adaptive scheduling and management of coexistence of base stations in the same time-frequency domain (superframes).
Goals of the WRAN project: