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Improved Iterative Detection and Achieved Throughputs of Multiband OFDM Systems Under Imperfect Channel Estimation
| Content Provider | Semantic Scholar |
|---|---|
| Author | Sadough, S. M. S. Duhamel, Pierre |
| Copyright Year | 2007 |
| Abstract | Assuming imperfect channel estimation, we propose an impro ved detector for ultra wideband (UWB) systems employing multiband orthogonal frequency-di vision multiplexing (MB-OFDM). By adopting a Bayesian approach involving the statistics of th e c annel estimation errors, we formulate an improved maximum-likelihood (ML) detection metric taki ng into account the characteristics of the channel estimates. As a first step, we propose a modified it erative detector based on maximum a posteriori which reduces the impact of channel uncertainty on the decod er performance, by an appropriate use of this metric. The results are compared to t hose obtained by using a detector based on a mismatched ML metric, which uses the channel estimate as if it was the perfect channel. In a second step, we calculate the information rates achieved by both th e improved and mismatched ML detectors, in terms of achievable outage rates. These outage rates are com pared to those provided by a theoretical (not practical) decoder defined as the best decoder in the presenc e of channel estimation errors. Numerical results over both uncorrelated Rayleigh fading channels an d realistic UWB channels show that the improved detector provides significant gains in terms of bit error rate and achievable outage rates, compared to the classically-used mismatched approach, wit out any increase in the receiver complexity. I. I NTRODUCTION Multiband orthogonal frequency-division multiplexing (M B-OFDM) is a spectrally efficient technique proposed for high data-rate, short-range ultra w ideband (UWB) applications operating in the range from 3.1 to 10.6 GHz [1]. In this scheme, the avail ble 7.5 GHz of UWB spectrum is divided into several subbands of at least 500 MHz bandwidt h, with a conventional OFDM modulation within each subband. The material in this paper was published in part at the 40-th Asilomar Conference on Signals, Systems, and Computers. August 25, 2007 DRAFT |
| File Format | PDF HTM / HTML |
| Alternate Webpage(s) | http://www.lss.supelec.fr/files/UGllcnJlIERVSEFNRUw=_OFDM_NewMet_110_V7.pdf |
| Language | English |
| Access Restriction | Open |
| Content Type | Text |
| Resource Type | Article |
