WLCp1-07: An Efficient Methodology for Optimal Discrete Bit-Loading with Spectral Mask Constraints

The recent adoption of ultra-wideband (UWB) technology for applications involving short-range very high data- rate wireless communication necessitates efficient allocation of system resources (bits, power etc.) because of the stringent spectral mask constraints. The multiband-OFDM(MB-OFDM) based UWB proposal permits usage of adaptive resource allocation over different sub-carriers so as to efficiently respond to the frequency-selective nature of the UWB channel.This paper proposes a new discrete bit-allocation methodology that results in minimizing power consumption for a fixed throughput and which appears to converge to the optimal solution faster than most known optimal discrete bit-loading methods. With peak- power-constraint and channel gain factor given for a sub-carrier, the sufficient condition for determining maximum permissible number of bits is also established. While earlier bit-loading algorithms have mostly targeted the ADSL-type systems, UWB application scenario is targeted in this paper to seek the total energy improvement factor with respect to a non-adaptive UWB system. However, the allocation methodology can be used for any multi-carrier based system.