Sub-sampled OFDM based sub-band ultra-wideband system
Paper i proceeding, 2012
In sub-band ultra-wideband (SUWB) systems, the use of spreading codes in conjunction with sub-banding enables energy efficient reduced sampling rate receiver designs. In this work, the orthogonal frequency division multiplexing (OFDM) technique is proposed for SUWB systems as a means to mitigate the multipath fading effects of the channel. The OFDM demodulation performed at the sub-sampled rate with reduced number of discrete Fourier transform (DFT) points provides scope for low power receiver implementations. Moreover, OFDM improves the flexibility as bandwidth resources can be allocated with improved granularity at integral multiples of the OFDM sub-channel bandwidth. The requisite correlation properties of the spreading codes is relaxed in the proposed OFDM-SUWB system and more number of spreading codes can be used when compared to the existing SUWB system. Also, a simple channel estimation method exploiting the low complexity advantage of the inherent spreading code based receiver is proposed. Simulation results in terms of the bit error rate (BER) performance are presented over the IEEE 802.15.4a channel models and also comparisons with the multi-band OFDM (MB-OFDM) system are made demonstrating the usefulness of the proposed scheme.
Discrete Fourier transforms
IEEE 802.15.4a
Subbands
Channel model
Multiband OFDM
Receiver design
Bandwidth resource
Orthogonal frequency division multiplexing
Channel estimation method
OFDM demodulation
MB-OFDM
Sub-sampled OFDM
Sub-banding
Correlation properties
Energy efficiency
Multipath fading effects
Low power receiver
Energy efficient
Integral multiples
Wireless telecommunication systems
Ultra wide band systems
Broadband networks
Spreading codes
UWB
Bit error rate (BER) performance
Sampling rates