A software defined radio testbed implementation

We report on the implementation of a software defined radio (SDR) based on state-of-the-art digital signal processors (DSPs), which are linked serially to PCs. While time critical operations are executed on specialised transmit and receive processors with a fixed block structure, the baseband processing is performed on highly flexible DSPs. The latter run several concurrent functionalities, such as the reception of data over a serial link, the assembly of symbols and frames for transmission, as well as receiver functions such as a fractionally spaced equaliser for synchronisation and mitigation of potentially dispersive channels under a DSP/BIOS system. The testbed system is capable of transmitting packets of data over the SDR link

Land deals in Africa: pioneers and speculators

Much African land currently has low productivity and has attracted investors leasing land as a speculative option on higher future prices or productivity. To be beneficial land deals need to induce productivity enhancing investments. Some of these will be publicly provided (infrastructure, agronomic knowledge), and some can only be provided by 'pioneer' investors who discover what works and create demonstration effects. Such pioneers can be rewarded for the positive externalities they create by being granted options on large areas of land. However, pioneers must be separated from speculators by screening and by requirements to work a fraction of the land