Improved Recursive Maximum Expansion Scheduling Algorithms for Uplink Single Carrier FDMA System

Single-carrier frequency division multiple access (SC-FDMA) has been selected as the uplink access scheme in the UTRA Long Term Evolution (LTE) due to its low peak-to-average power ratio properties. Nevertheless, in order to achieve such a benefit, it requires a localized allocation of the resource blocks (RBs), which naturally imposes a severe constraint on the scheduler design. In this paper, two improved recursive maximum expansion scheduling algorithms for SC-FDMA are proposed. Compared with conventional recursive maximum expansion (RME) scheme in which UE can only expand the resource allocation on neighboring RBs with the highest metrics, in proposed improved recursive maximum expansion (IRME) scheme, higher degree of freedom in RB expansion is achieved by allowing RB expansion within certain ranking threshold. Moreover, to further increase the flexibility in resource allocation, multiple surviving paths are introduced in proposed improved tree-based recursive maximum expansion (ITRME) scheme. The simulation results show that, compared with conventional RME scheme, the proposed IRME scheme can exhibit the gain about 15% in terms of spectral efficiency with a linear increase of computational complexity, and the performance can be further improved to 18% with proposed ITRME scheme if further higher complexity is permitted.