Patent ID: 8218420
Filing Date: 2012-07-10
Classification: H04W

Abstract:
1. A method for allocating resources in an OFDMA system downlink channel having a selected bandwidth and an FFT size, comprising: within a network node in the OFDMA system: determining a number of usable subcarriers, excluding null guard tones, within the bandwidth of the OFDMA system for each symbol interval, the usable subcarriers spanning contiguous block of frequencies from a first null guard band to a second null guard band; determining a size for a sub physical resource allocation block (SPRB), each SPRB representing a predetermined number of consecutive subcarriers within the bandwidth in each symbol interval; based on the number of usable subcarriers, determining a number of SPRBs to be associated with an evolving virtual resource block (E-VRB), each E-VRB representing the resources available for a corresponding user; based on the number of SPRBs to be associated with each E-VRB, determining a number of E-VRBs to be used in the OFDMA system for a predetermined number of symbol intervals; dividing the predetermined number of symbol intervals into a plurality of stages ordered successively in time; allocating the SPRBs corresponding to the symbol intervals for a first one of the stages to the E-VRBs such that each E-VRB has contiguous SPRBs, wherein a first one of the E-VRBs is adjacent the first null guard band and a last one of the E-VRBs is adjacent the second null guard band, and wherein an intervening portion of the E-VRBs extend between the first E-VRB and the last E-VRB; for each stage subsequent to the first one of stages, allocating the SPRBs corresponding to the symbol intervals of the stage to the E-VRBs according to increasing frequency diversity as compared to an immediately-preceding one of the stages such that the first E-VRB spreads in frequency towards the second null guard band, the intervening portions of the E-VRBs spread in frequency towards both the first and second null guard bands, and the last E-VRB spreads in frequency towards the first null guard band; and transmitting over the downlink channel corresponding users according to their E-VRBs.