Reconfigurable Radio System (RSS. Reconfigurable radio is a state-of-the-art requirement for wireless links in general. In case of microwave, propagation conditions change, due to the weather. Moreover, radio links are supposed to create little interference and be energy-efficient. If the traffic is temporarily low, we can adapt power consumption and throughput, accordingly. Such adaptation may include the use of less complex modulation formats, waveforms better adapted to lower spectrum efficiency and adaptation of the spectrum utilization. Figure 26 shows the various elements of a RRS, which perform its reconfiguration management operations. The joint radio resource management element is responsible for coordinating the negotiations between reconfigurable network elements, and for ensuring that the optimal utilisation of radio resources by all network elements is achieved. The radio access technologies (RATs) in each network element possess their own individual resource management, mobility management, and other link control mechanisms, which are in turn defined within their RAT standards. The RRS's reconfiguration management system interfaces with these mechanisms, thereby enabling it to adjust the radio resource utilisation of each network element. A network operator is able to exercise control over reconfiguration operations through the use of policies, which provide network elements with a set of predefined reconfiguration objectives and restrictions. Policy-based management is also beneficial, as it enables the autonomous reconfiguration of network elements without requesting/obtaining permission from the network operator in the core network. Dynamic spectrum access/allocation (DSA) enables the dynamic allocation of spectrum to accommodate each reconfigurable network element, and in so doing ensures both efficient use of the available spectrum, adherence to national spectrum licensing regulations and best energy efficiency. DSA elements in separate RRSs can also conduct negotiations, thereby enabling spectrum leasing and sharing. The main challenge in this context is three-fold. We need a reconfigurable user plane, i.e. a functional pipeline doing all the signal processing from data bits to waveforms at high signal processing speed. To our knowledge, the highest symbol rate ever handled within an adaptive user plane is in the research prior to LTE, where 100 MSymbols/s processing was used to achieve 1 Gb/s [43]. This research direction was halted since the maximum symbol rate for ...
