  Adaptive Radio Resource Allocation is essential for guaranteeing high
bandwidth and power utilization as well as satisfying heterogeneous
Quality-of-Service requests regarding next generation broadband multicarrier
wireless access networks like LTE and Mobile WiMAX. A downlink OFDMA
single-cell scenario is considered where heterogeneous Constant-Bit-Rate and
Best-Effort QoS profiles coexist and the power is uniformly spread over the
system bandwidth utilizing a Uniform Power Loading (UPL) scenario. We express
this particular QoS provision scenario in mathematical terms, as a variation of
the well-known generalized assignment problem answered in the combinatorial
optimization field. Based on this concept, we propose two heuristic search
algorithms for dynamically allocating subchannels to the competing QoS classes
and users which are executed under polynomially-bounded cost. We also propose
an Integer Linear Programming model for optimally solving and acquiring a
performance upper bound for the same problem at reasonable yet high execution
times. Through extensive simulation results we show that the proposed
algorithms exhibit high close-to-optimal performance, thus comprising
attractive candidates for implementation in modern OFDMA-based systems.
